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The Indian Institutes of Technology is a prestigious group of autonomous public engineering and management institutes of India. The IITs are governed by the Institutes of Technology Act, 1961 which has declared them as "institutions of national importance", and lays down their powers, duties, framework for governance etc. The Institutes of Technology Act, 1961 lists sixteen institutes located at Bhubaneswar, Chennai, Delhi, Gandhinagar, Guwahati, Hyderabad, Indore, Jodhpur, Kanpur, Kharagpur, Mandi, Mumbai, Patna, Ropar, Roorkee and Varanasi. Each IIT is an autonomous institution, linked to the others through a common IIT Council, which oversees their administration. The IITs award degrees ranging from B.Tech to PhD.The IITs have a common admission process for undergraduate admissions. It was called IIT-JEE, which was replaced by Joint Entrance Examination in 2013. The post-graduate level program that awards M.Tech degree in engineering is administered by the older IITs . M.Tech admission is done on the basis of Graduate Aptitude Test in Engineering . In addition to B.Tech and M.Tech programs IITs also award other graduate degrees such as M.Sc in Engineering, Maths, Physics and Chemistry, MBA, PhD etc. Admission to these programs of IITs is done through Common Admission Test, Joint Admission Test for Masters and Common Entrance Examination for Design . Wikipedia.

Maity R.,Indian Institute of Technology Kharagpur
Hydrological Processes | Year: 2012

In this paper, Split Markov Process (SMP) is developed to assess one-step-ahead variation of daily rainfall at a rain gauge station. SMP is an advancement of general Markov Process and specially developed for probabilistic assessment of change in daily rainfall magnitude. The approach is based on a first-order Markov chain to simulate daily rainfall variation at a point through state/sub-state transitional probability matrix (TPM). The state/sub-state TPM is based on the historical transitions from a particular state to a particular sub-state, which is the basic difference between SMP and general Markov Process. The cumulative state/sub-state TPM is represented in a contour plot at different probability levels. The developed cumulative state/sub-state TPM is used to assess the possible range of rainfall in next time step, in a probabilistic sense. Application of SMP is investigated for daily rainfall at four rain gauge stations - Khandwa, Jabalpur, Sambalpur, and Puri, located at various parts in India. There are 99years of record available out of which approximately 80% of data are used for calibration, and 20% of data are used to assess the performance. Thus, 80years of daily monsoon rainfall is used to develop the state/sub-state TPM, and 19years data are used to investigate its performance. Model performance is assessed in terms of hit rate (HR), false alarm rate (FAR), and percentage captured. It is found that percentage captured is maximum for Khandwa (70%) and minimum for Sambalpur (44%) whereas hit rate is maximum for Sambalpur and minimum for Khandwa (73%). FAR is around 30% or below for Jabalpur, Sambalpur, and Puri. FAR is maximum for Khandwa (37%). Overall, the assessed range, particularly the upper limit, provides a quantification possible extreme value in the next time step, which is a very useful information to tackle the extreme events, such as flooding, water logging and so on. © 2011 John Wiley & Sons, Ltd.

Singh A.,Indian Institute of Technology Kharagpur
Water Resources Management | Year: 2012

Direct measurement of groundwater recharge is nearly impossible. So there are various direct and indirect methods and sophisticated models have been used for its estimation. However, the use of multiple approaches has been recommended to estimate the groundwater recharge since each individual approach is associated with some limitations. In many cases, different approaches complement each other and help refine the conceptual model of recharge processes. In this study, a simple watertable model, which is a combination of the groundwater budget and watertable fluctuation, was developed. The model is unique, simple, cost effective, and easy to apply. The model requires input parameters that are readily available or obtainable and which can be accurately measured. The model was applied to estimate the seasonal long-term (30 years, e. g., from 1981 to 2011) groundwater recharge of a canal command located in Jhajjar district of Haryana State (India), where watertable is rising. The results were analysed to provide an overview of the process dynamics that led to watertable rise in the command area. The calculated watertable depths reasonably matched with the observed ones for all the seasons which were confirmed by the high R-squared value of 0. 963. The mean error and root mean squared error were low at -0. 0068 and 0. 2548 m, respectively, while the model efficiency was 0. 83. Different water management alternatives were studied to examine the effect of variation in model parameters on its output. Among the alternatives studied, increased tubewell draft had a higher impact on the overall water balance followed by reduced rice area and canal lining, respectively. © 2012 Springer Science+Business Media Dordrecht.

Kashid S.S.,Walchand Institute of Technology | Maity R.,Indian Institute of Technology Kharagpur
Journal of Hydrology | Year: 2012

Prediction of Indian Summer Monsoon Rainfall (ISMR) is of vital importance for Indian economy, and it has been remained a great challenge for hydro-meteorologists due to inherent complexities in the climatic systems. The Large-scale atmospheric circulation patterns from tropical Pacific Ocean (ENSO) and those from tropical Indian Ocean (EQUINOO) are established to influence the Indian Summer Monsoon Rainfall. The information of these two large scale atmospheric circulation patterns in terms of their indices is used to model the complex relationship between Indian Summer Monsoon Rainfall and the ENSO as well as EQUINOO indices. However, extracting the signal from such large-scale indices for modeling such complex systems is significantly difficult. Rainfall predictions have been done for 'All India' as one unit, as well as for five 'homogeneous monsoon regions of India', defined by Indian Institute of Tropical Meteorology. Recent 'Artificial Intelligence' tool 'Genetic Programming' (GP) has been employed for modeling such problem. The Genetic Programming approach is found to capture the complex relationship between the monthly Indian Summer Monsoon Rainfall and large scale atmospheric circulation pattern indices - ENSO and EQUINOO. Research findings of this study indicate that GP-derived monthly rainfall forecasting models, that use large-scale atmospheric circulation information are successful in prediction of All India Summer Monsoon Rainfall with correlation coefficient as good as 0.866, which may appears attractive for such a complex system. A separate analysis is carried out for All India Summer Monsoon rainfall for India as one unit, and five homogeneous monsoon regions, based on ENSO and EQUINOO indices of months of March, April and May only, performed at end of month of May. In this case, All India Summer Monsoon Rainfall could be predicted with 0.70 as correlation coefficient with somewhat lesser Correlation Coefficient (C.C.) values for different 'homogeneous monsoon regions'. © 2012 Elsevier B.V.

Saha P.,Indian Institute of Technology Kharagpur | Mishra P.K.,College of Engineering, Pune
International Journal of Advanced Manufacturing Technology | Year: 2010

Electro-discharge machining (EDM) is a widely accepted nontraditional machining process used mostly for machining materials difficult to machine by conventional shearing process. Surface modification by powder metallurgy sintered tools is an uncommon aspect of EDM. Of late, it is being explored by many researchers. In the present paper, attempts have been made to model the surface modification phenomenon by EDM with artificial neural networks. Two output measures, material transfer rate and average layer thickness, have been correlated with different process parameters and presented in the form of plots. The predicted results are matching well with the experimental results. © 2010 Springer-Verlag London Limited.

Singh A.,Indian Institute of Technology Kharagpur
Journal of Irrigation and Drainage Engineering | Year: 2012

Good quality soil and water resources are often limited in arid and semi-arid regions; however, poor quality groundwater can be used conjunctively with good quality canal water to fulfill crop water demand in these areas. In the present study, a linear programming model was developed for the optimal land and water resources allocation to maximize net annual returns from a command area located in Jhajjar district of Haryana, India. The water production functions were developed and incorporated in the model to estimate the crop yield under different qualities of irrigation water. A groundwater balance constraint was imposed on the model, which mitigated the waterlogging problems while making optimal use of land and water resources. The model results show a reduction in rice and mustard areas against an increase in cotton, sugarcane, and wheat under optimal conditions. Under the optimal land and water allocation the groundwater use increases, which in turn mitigates the waterlogging and salinity problems of the command area. The net annual return from the command area increased by more than 20% under optimal allocations. The sensitivity analysis of the model parameters show that better price of crops is the most sensitive parameter followed by the crop area and cost of cultivation. State agencies and farmers involved in the actual agricultural production process are advised to practice conjunctive use of canal water and groundwater to maximize their farm income. This strategy could also mitigate further rise in the water table in the command area without installing expensive drainage systems, which is also not feasible because the groundwater quality is poor and the drainage water may pose a serious disposal problem. © 2012 American Society of Civil Engineers.

Majumdar J.D.,Indian Institute of Technology Kharagpur
Surface and Coatings Technology | Year: 2010

In the present study, an attempt has been made to develop in-situ iron silicide dispersed surface on mild steel substrate by laser surface alloying with silicon using a high-power continuous wave CO 2 laser. The effect of laser surface remelting of the alloyed surface using argon and nitrogen (with and without graphite coating) as shrouding environment has also been studied. The microstructure of laser surface alloyed mild steel with silicon consists of uniformly dispersed iron silicide in grain refined α-iron matrix with an improved microhardness to 575 VHN as compared to 150 VHN of as-received mild steel substrate. Surface remelting in Ar atmosphere coarsened the microstructure and reduced the area fraction of silicide and hence, reduction in the microhardness to 450 VHN. Surface remelting in nitrogen increased the microhardness to 740 VHN due to the formation of iron nitrides in addition to the presence of silicides. Graphite coating prior to remelting improved the microhardness to 800 VHN due to the presence of martensites along with nitrides and silicides. A maximum enhancement in wear resistance was achieved when remelting was done in nitrogen environment with carbon deposition. The mechanism of wear was found to be predominantly abrasive in nature as compared to adhesive and oxidative in as-received mild steel. © 2010.

Ganguly S.,Indian Institute of Technology Kharagpur
Chemical Engineering Research and Design | Year: 2011

Water is injected into oil-bearing porous rock for displacement of oil. Water tends to flow through high permeablity streaks, leaving significant amount of oil in place, unless the streaks are plugged by structure-forming fluids such as, polymer-gels. Cr(III)-polyacrylamide gel finds an use even in production well, as this gel structure offers easy flow of oil, apart from restricting water flow. The resistances that water and oil encounter, while flowing through the gel structure are characterized in this paper. The permeability of Cr(III)-polyacrylamide gel, held in tubes was evaluated as function of oil and water flow rates. This was observed that immediately after the rupture, a new pore space was created by the injected fluid. Same pathways were used by the other phase, i.e., water or oil, injected subsequently. The volume of the pathway within the gel structure was also monitored during the flow experiments. After complete recovery of the new pore space, the permeability was found to increase at higher flow rates. The change in permeability was completely reversible, and a cycle of step-wise ascent and descent in flow rates did not show any significant hysteresis. A theoretical model is developed that accounts for the rupture in the gel, and the deformation of the fracture inside the gel due to imposed pressure gradient. The model explains the power-law relationship between permeability and flow rate, as observed in experiments. The model identifies a ratio of interfacial to elastic deformation, in terms of a dimensionless parameter, σ/(GL). This ratio controls the relative reduction in water permeability with respect to the reduction in oil permeability. Experiments were conducted in Berea sandstone rock, and similar trends, as described above were observed. © 2011 The Institution of Chemical Engineers.

Banerjee N.,Indian Institute of Technology Kharagpur | Sharma P.,Indian Institute of Science
Monthly Notices of the Royal Astronomical Society | Year: 2014

We study the interplay between turbulent heating, mixing, and radiative cooling in an idealized model of cool cluster cores. Active galactic nuclei (AGN) jets are expected to drive turbulence and heat cluster cores. Cooling of the intracluster medium (ICM) and stirring by AGN jets are tightly coupled in a feedback loop. We impose the feedback loop by balancing radiative cooling with turbulent heating. In addition to heating the plasma, turbulence also mixes it, suppressing the formation of cold gas at small scales. In this regard, the effect of turbulence is analogous to thermal conduction. For uniform plasma in thermal balance (turbulent heating balancing radiative cooling), cold gas condenses only if the cooling time is shorter than the mixing time. This condition requires the turbulent kinetic energy to be ≳ the plasma internal energy; such high velocities in cool cores are ruled out by observations. The results with realistic magnetic fields and thermal conduction are qualitatively similar to the hydrodynamic simulations. Simulations where the runaway cooling of the cool core is prevented due to mixing with the hot ICM show cold gas even with subsonic turbulence, consistent with observations. Thus, turbulent mixing is the likely mechanism via which AGN jets heat cluster cores. The thermal instability growth rates observed in simulations with turbulence are consistent with the local thermal instability interpretation of cold gas in cluster cores. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Sinha S.,Tata Consultancy Services Ltd. | Sarmah S.P.,Indian Institute of Technology Kharagpur
Computers and Industrial Engineering | Year: 2010

This paper analyzes the coordination and competition issues in a two-stage supply-chain distribution system where two vendors compete to sell differentiated products through a common retailer in the same market. The demand of a product not only depends on its own price, but also on the price of the other. Mathematical models have been developed to analyze the coordination issues under three different contexts: (i) price competition without channel coordination; (ii) price competition with channel coordination; and (iii) global coordination. It has been shown that under certain conditions, price competition through the dynamic process of price adjustment reaches the Nash-Bertrand equilibrium. Conditions have been derived for the Nash-Bertrand equilibrium to be dynamically stable. Further, it has been shown that duopoly competition can make consumers better-off or worse-off depending on the degree of product differentiation and the type of the product; while coordination enhances overall supply-chain profitability. The model is illustrated with suitable numerical examples. © 2010 Elsevier Ltd. All rights reserved.

Biradha K.,Indian Institute of Technology Kharagpur | Su C.-Y.,Sun Yat Sen University | Vittal J.J.,National University of Singapore | Vittal J.J.,Gyeongsang National University
Crystal Growth and Design | Year: 2011

In recent years, Asian countries, especially China and India, are making significant progress in the field of crystal engineering. The recent surge of publications in this area from these countries in high impact journals is a tangible measure of this activity. An important milestone in this direction was the China-India-Singapore Symposium on Crystal Engineering recently held at the National University of Singapore. This symposium brought researchers working in this field to meet, discuss, present, and exchange their research work and has generated momentum to further accelerate the growth of this field. This perspective highlights the recent advances discussed by the researchers at this symposium in the fast growing field of crystal engineering.(Figure Presented) © 2011 American Chemical Society.

Mukherjee R.,Indian Institute of Technology Kharagpur | Sharma A.,Indian Institute of Technology Kanpur
ACS Applied Materials and Interfaces | Year: 2012

The surface of a thin elastic bilayer becomes spontaneously unstable when it is brought in proximity to another rigid contactor. The instability patterns, which are random and isotropic, exhibit a dominant lateral length scale of instability λ, which linearly scales with the bilayer thickness (h) as: λ = R Fh. It is known that for an elastic bilayer, R F exhibits a nonlinear dependence on the ratios of individual film thicknesses (H) and shear moduli (M) of the two constituent layers, and can have values as low as 0.5 under specific conditions. This is in contrast to a near constant value of R F ≈ 3 for a single layer elastic film.(1) These isotropic contact instability patterns in a bilayer can be ordered, aligned and modulated using a topographically patterned stamp. The precise morphology of the aligned structures depends on commensuration between λ and the stamp periodicity (λ P), and on the intersurface separation distance. A variety of patterns, like an array of circular holes, double periodic channels, etc., in addition to a positive and a negative replica of the stamp pattern, can be engineered with a simple stamp having 1D grating structure. A lower value of R F in a bilayer allows generating patterns with sub 500 nm lateral resolution, which is impossible to create by elastic contact lithography (ECL) of a single layer film due to strong surface tension effects in ultrathin films. Thus, control of elastic instability in a bilayer with a patterned stamp represents a flexible soft lithography tool allowing modulation of length scales, morphology, and order. © 2011 American Chemical Society.

Chatterjee P.N.,Indian Institute of Technology Kharagpur | Roy S.,Indian Institute of Technology Bhubaneswar
Tetrahedron | Year: 2012

A nucleophilic substitution of allylic alcohols with carbon (arene, heteroarene, allyltrimethylsilane, and 1,3-dicarbonyl compound), sulfur (thiol), oxygen (alcohol), and nitrogen (sulfonamide) nucleophiles has been demonstrated using an in house developed [Ir(COD)(SnCl 3)l(μ-Cl)] 2 heterobimetallic catalyst in 1,2-dichloroethane to afford the corresponding allylic products in moderate to excellent yields. In 4-hydroxycoumarin, allylation occurs at the 3-position. The diaryl-substituted allylic alcohols undergo disproportionation in presence of the heterobimetallic catalyst to provide the corresponding alkenes and chalcones. An electrophilic mechanism is proposed from Hammett correlation study. © 2012 Elsevier Ltd. All rights reserved.

Ram M.,Indian Institute of Technology Kharagpur
Journal of Alloys and Compounds | Year: 2010

Solution-based chemical method has been used to synthesize the LiFe2/5Ni3/10Co3/10VO4 ceramics. Frequency dependence of dielectric constant (εr) at different temperatures shows a dispersive behavior at low frequencies. Temperature dependence of εr at different frequencies exhibits the dielectric anomalies in εr. Variation of tangent loss (tan δ) with frequency at different temperatures demonstrates dielectric relaxation in the material. The variation of log (τd) with temperature obeys the Vogel-Fulcher law. © 2009 Elsevier B.V. All rights reserved.

Das A.N.,Steel Authority of India Ltd | Sarmah S.P.,Indian Institute of Technology Kharagpur
European Journal of Industrial Engineering | Year: 2010

This paper presents a concise review of the optimisation models for the preventive repair/replacement/inspection of components/assemblies/subsystems with the aim of critically examining their prospects as well as limitations in implementation in heavy process industries. The survey covers models under two major categories: models for single-unit systems and for multi-unit systems. Single-unit models are presented under three subcategories of two-state models, three-state models and multistate models; multi-unit models encompass models for the grouping of component replacements under three types of replacements: corrective, opportunistic and preventive. Each of the models and their variations are followed by a discussion on implementation problems and prospects particularly in process industries. Copyright © 2010 Inderscience Enterprises Ltd.

Jana A.K.,Indian Institute of Technology Kharagpur
Applied Energy | Year: 2010

Increasing energy demand, consequently high crude oil prices and growing concern for pollution motivated the researchers to explore more energy-efficient and environment-friendly process technologies. Although the heat integrated distillation has been researched for a number of decades, unfortunately it has not yet been commercialized mainly due to high investment cost, complex equipment design, control problem in consequence of severe interaction and nonlinearity, and lack of experimental data at sufficiently large scale to verify the theoretical predictions. It is true that some progress has been made in theory but for practical applications many questions still remain. Among the broader research needs the following areas are identified for heat integrated distillation column: rigorous dynamic modeling, optimal design, multiple steady state analysis, system identification, synthesis and implementation of high-quality nonlinear control, and importantly experimental evaluation. It is also suggested to investigate the feasibility of heat integration in the reactive distillation schemes and in the two distillation columns having no direct connections. © 2009 Elsevier Ltd. All rights reserved.

Roy S.S.,National Institute of Technology Durgapur | Pratihar D.K.,Indian Institute of Technology Kharagpur
Robotics and Computer-Integrated Manufacturing | Year: 2013

This paper deals with a detailed analysis on kinematics, dynamics, stability and energy consumption of a realistic six-legged robot. The aim of this study is to extend a previous work of Roy et al. [1], in order to estimate optimal feet forces and joint torques of the six-legged robot generating wave-gaits with four different duty factors and deal with its stability issues. Two different approaches are developed to determine optimal feet forces. In the first approach, minimization of the norm of feet forces is carried out using a least square method, whereas minimization of the norm of joint torques is performed in the second approach. The second approach is found to be more energy efficient compared to the first one. The maximum values of feet forces and joint torques are seen to decrease with the increase of duty factor. The effects of walking parameters, namely velocity, stroke and duty factors have been studied on energy consumption and stability of the robot. The variations of average power consumption and specific energy consumption with the velocity and stroke are compared for four different duty factors. Wave gait with a low duty factor is found to be more energy-efficient compared to that with a high duty factor at the highest possible velocity. © 2012 Elsevier Ltd. All rights reserved.

Majumder A.K.,Indian Institute of Technology Kharagpur | Barnwal J.P.,Advanced Materials and Processes
Fuel | Year: 2011

It is reported in the literature that a water-only cyclone (WOC), a centrifugal gravity concentrator, is an alternative to froth flotation to treat coal fines (below 0.5 mm). This unit overcomes the inherent limitations of froth flotation and the dense-medium cyclone techniques as it requires no chemicals or artificial medium. The literature dealing with WOC performance to treat coal fines is also limited and as a result it is not well established how the design variables affect the performance of a WOC while treating coal fines. Therefore, an attempt has been made to develop regression models based on factorial design of experiments to quantify the effects of major design variables of a WOC on the beneficiation characteristics of a typical coal fine sample. Further attempts have been made to provide possible explanations on the observed trends of the data based on simple hydrodynamic analyses. © 2010 Elsevier Ltd. All rights reserved.

Sadhukhan A.K.,National Institute of Technology Durgapur | Gupta P.,National Institute of Technology Durgapur | Saha R.K.,Indian Institute of Technology Kharagpur
Fuel | Year: 2011

Single particle devolatilization followed by combustion of the residual coal char particle has been analyzed in a batch-fluidized bed. The kinetic scheme with distributed activation energy is used for coal devolatilization while multiple chemical reactions with volume reaction mechanism are considered for residual char combustion. Both the models couple kinetics with heat transfer. Finite Volume Method (FVM) is employed to solve fully transient partial differential equations coupled with reaction kinetics. The devolatilization model is used to predict the devolatilization time along with residual mass and particle temperature, while the combined devolatilization and char combustion model is used to predict the overall mass loss and temperature profile of coal. The computed results are compared with the experimental results of the present authors for combustion of Indian sub-bituminous coal (15% ash) in a fluidized bed combustor as well as with published experimental results for coal with low ash high volatile matter. The effects of various operating parameters like bed temperature, oxygen mole fraction in bulk phase on devolatilization time and burn-out time of coal particle in bubbling fluidized bed have been examined through simulation. © 2011 Elsevier Ltd. All rights reserved.

Gupta B.,Indian Institute of Technology Kharagpur | Ilg P.,ETH Zurich
Polymers | Year: 2013

The Landau-de Gennes theory provides a successful macroscopic description of nematics. Cornerstone of this theory is a phenomenological expression for the effective free energy as a function of the orientational order parameter. Here, we show how such a macroscopic Landau-de Gennes free energy can systematically be constructed for a microscopic model of liquid crystals formed by interacting mesogens. For the specific example of the Gay-Berne model, we obtain an enhanced free energy that reduces to the familiar Landau-de Gennes expression in the limit of weak ordering. By carefully separating energetic and entropic contributions to the free energy, our approach reconciles the two traditional views on the isotropic-nematic transition of Maier-Saupe and Onsager, attributing the driving mechanism to attractive interactions and entropic effects, respectively. © 2013 by the authors.

Hazra J.,IBM | Sinha A.K.,Indian Institute of Technology Kharagpur
European Transactions on Electrical Power | Year: 2011

This paper presents a multi-objective optimal power flow technique using particle swarm optimization. Two conflicting objectives, generation cost, and environmental pollution are minimized simultaneously. A multi-objective particle swarm optimization method is used to solve this highly nonlinear and non-convex optimization problem. A diversity preserving technique is incorporated to generate evenly distributed Pareto optimal solutions. A fuzzy membership function is proposed to choose a compromise solution from the set of Pareto optimal solutions. The algorithm is tested on IEEE 30 and 118 bus systems and its effectiveness is illustrated. © 2010 John Wiley & Sons, Ltd.

Jana M.,National Institute of Technology Rourkela | Bandyopadhyay S.,Indian Institute of Technology Kharagpur
Journal of Physical Chemistry B | Year: 2013

Atomistic molecular dynamics (MD) simulations of host-guest inclusion complexes of β-cyclodextrin (BCD) and zwitterionic phenylalanine (zPHE) following two possible orientations of zPHE in aqueous solutions have been carried out. The guest induced structural changes of BCD and the microscopic properties of surrounding water have been explored. The results obtained for the complex molecules were compared with those obtained for free BCD and free zPHE molecules. It is found that irrespective of the orientation, the complexation of BCD and zPHE (1:1) is associated with loss of configurational entropy. Besides, the net configurational entropy is found to differ depending upon its orientation inside the BCD cavity. Interestingly, within the simulation length scale it is found that the relatively hydrophobic aromatic moiety of zPHE prefers to stay within the hydrophobic cavity of BCD, irrespective of its orientation. Further, nonuniform distribution and altered tetrahedral ordering of hydration water molecules around the complex molecules as compared to that around the free forms are correlated well with their conformational flexibilities. © 2013 American Chemical Society.

Palaniyappan A.,University of Alberta | Alphonse R.,Indian Institute of Technology Kharagpur
Experimental Gerontology | Year: 2011

Senescence is the result of an imbalance between free radical production and antioxidant defenses, with concomitant oxidative stress and age-dependent functional decline. This process is especially evident in the immune cells, which use free radicals in their functions and suffer a senescent deterioration probably linked to oxygen stress. We hypothesize that oxidative damage and antioxidant imbalance may play a critical role in the immune dysfunction in aging. In the present study, we investigated this hypothesis in aged rats by treatment with alpha-lipoic acid (α-LA). We studied the effect of α-LA on immune function by examining immunomodulating factors in the plasma. Then we examined oxidative damage and antioxidant defense systems in the plasma. We found out that immune dysfunction in aged animals is associated with increased oxidative damage and decreased antioxidant status and treatment with α-LA effectively elevated immune function, decreased oxidative insult and enhanced antioxidant status. These results suggest that α-LA may be effective in improving immune function in aging through decreasing oxidative damage and revitalizing antioxidants in blood. © 2011.

Mahata G.C.,P.A. College | Goswami A.,Indian Institute of Technology Kharagpur
Computers and Industrial Engineering | Year: 2013

This paper considers inventory models for items with imperfect quality and shortage backordering in fuzzy environments by employing two types of fuzzy numbers, which are trapezoidal and triangular. Two fuzzy models are developed. In the first model the input parameters are fuzzified, while the decision variables are treated as crisp variables. In the second model, not only the input parameters but also the decision variables are fuzzified. For each fuzzy model, a method of defuzzification, namely the graded mean integration method, is employed to find the estimate of the profit function in the fuzzy sense, and then the optimal policy for the each model is determined. The optimal policy for the second model is determined by using the Kuhn-Tucker conditions after the defuzzification of the profit function. Numerical examples are provided in order to ascertain the sensitiveness in the decision variables with respect to fuzziness in the components. © 2012 Elsevier Ltd. All rights reserved.

Das A.K.,International Institute of Information Technology, Hyderabad | Goswami A.,Indian Institute of Technology Kharagpur
Journal of Medical Systems | Year: 2013

Connected health care has several applications including telecare medicine information system, personally controlled health records system, and patient monitoring. In such applications, user authentication can ensure the legality of patients. In user authentication for such applications, only the legal user/patient himself/herself is allowed to access the remote server, and no one can trace him/her according to transmitted data. Chang et al. proposed a uniqueness-and-anonymity-preserving remote user authentication scheme for connected health care (Chang et al., J Med Syst 37:9902, 2013). Their scheme uses the user's personal biometrics along with his/her password with the help of the smart card. The user's biometrics is verified using BioHashing. Their scheme is efficient due to usage of one-way hash function and exclusive-or (XOR) operations. In this paper, we show that though their scheme is very efficient, their scheme has several security weaknesses such as (1) it has design flaws in login and authentication phases, (2) it has design flaws in password change phase, (3) it fails to protect privileged insider attack, (4) it fails to protect the man-in-the middle attack, and (5) it fails to provide proper authentication. In order to remedy these security weaknesses in Chang et al.'s scheme, we propose an improvement of their scheme while retaining the original merit of their scheme. We show that our scheme is efficient as compared to Chang et al.'s scheme. Through the security analysis, we show that our scheme is secure against possible attacks. Further, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to ensure that our scheme is secure against passive and active attacks. In addition, after successful authentication between the user and the server, they establish a secret session key shared between them for future secure communication. © 2013 Springer Science+Business Media New York.

Chatterjee S.,National Institute of Technology Rourkela | Bhattacherjee A.,Indian Institute of Technology Kharagpur
Engineering Applications of Artificial Intelligence | Year: 2011

Measuring the quality parameters of materials at mines is difficult and a costly job. In this paper, an image analysis-based method is proposed efficiently and cost effectively that determines the quality parameters of material. The image features are extracted from the samples collected from a mine and modeled using neural networks against the actual grade values of the samples generated by chemical analysis. The dimensions of the image features are reduced by applying the genetic algorithm. The results showed that only 39 features out of 189 features are sufficient to model the quality parameter. The model was tested with the testing data set and the result revealed that the estimated grade values are in good agreement with the real grade values (R 2=0.77). The developed method was then applied to a case study mine of iron ore. The case study results show that proposed image-based algorithm can be a good alternative for estimating quality parameters of materials at a mine site. The effectiveness of the proposed method was verified by applying it on a limestone deposit and the results revealed that the method performed equally well for the limestone deposit. © 2010 Elsevier Ltd. All rights reserved.

Rajeshwari P.,Indian Institute of Technology Kharagpur
Materials Today: Proceedings | Year: 2015

Carbon Nano-Tubes (CNTs) have stimulated extreme research into a broad range of applications in electronics, structural materials and chemical processing due to their remarkable structural, mechanical and thermal properties. In the present article, attempts have been made to investigate the effect of incorporation of multiwall carbon nanotubes (MWNTs) on microstructure and mechanical properties of High density polyethylene (HDPE) / MWNTs composites using High resolution transmission electron microscopy (HR-TEM), Atomic force microscopy (AFM) and nano-indentation methods. A standard Berkovich indenter has been used for indentation at normal load (200. μN). The MWNTs at various concentrations specifically 0.20, 0.40, 0.60 and 0.80. wt. % were dispersed in the HDPE polymer matrix using melt mixing process. The HR-TEM and AFM microstructure images reveal the homogeneous dispersion of MWNTs in the HDPE polymer matrix. The mechanical property (viz., Hardness and Elastic modulus) of MWNTs / HDPE composites was enhanced appreciably with the increase in concentration of multi wall carbon nanotubes. © 2015 Elsevier Ltd.

The increasing threats of multidrug resistant fungal pathogens, several studies have been focused to identify novel antifungal plant peptides with unique characteristics. Plants have been defending themselves against fungal infection by generating effective antifungal molecules. Here, a novel antifungal peptide with molecular mass of 4.0 kDa was purified from the pericarp of D. stramonium using reversed phase chromatography system after acetic acid extraction. Presence of sugar moieties (-GlcNAc-) in the peptide have been confirmed using thin layer chromatographic (TLC), CD polarimeter, and MALDI MS analysis. Complete amino acid sequences of this peptide by PSD MALDI MS analysis revealed to contain hydroxyproline in the centre of two cysteine residues. After sequencing "TFPKCAPTRhyPhy PGPKhyPCDINNFKSKFWHIWRA-(GlcNAc-)Asn" peptide named as "datucin." Antifungal sensitivity of datucin have been performed for both planktonic cells and biofilm phenotype ofa multidrug resistant clinical isolates, C. albicans and showed a MIC and MBEC values of 1 microM and 2 microM, respectively. Hence, D. stramonium offers a potential source of novel antifungal peptide datucin with possible utility in antifungal chemotherapy.

Mukherjee K.,Indian Institute of Technology Kharagpur
Nanotechnology | Year: 2010

Solution based synthesis routes are attractive for making tailor-made nanostructures for electroceramics in a simple and cost-effective way. The gas sensing characteristics of semiconducting oxide gas sensors strongly depend on the adsorption and desorption of gases over the sensing surface. The morphology of the sensing element is known to influence the adsorption and desorption of gases and thereby the sensing performance of the material. In the present work a Pechini based solution synthesis route is adopted in order to synthesize magnesium zinc ferrite gas sensors in nanoparticle, nanotube and thin film forms. The hydrogen gas sensing characteristics of these sensing elements are compared as a function of test gas concentration and operating temperature. The influences of the morphology of the magnesium zinc ferrite sensing elements on the hydrogen sensing characteristics are discussed.

Sharma S.P.,Indian Institute of Technology Kharagpur | Verma S.K.,National Geophysical Research Institute
Geophysical Prospecting | Year: 2011

The problem of equivalence in direct current (DC) resistivity and electromagnetic methods for a thin resistive and conducting layer is well-known. Attempts have been made in the past to resolve this problem through joint inversion. However, equivalence still remains an unresolved problem. In the present study, an effort is made to reduce non-uniqueness due to equivalence using global optimization and joint inversion by successive refinement of the model space. A number of solutions derived for DC resistivity data using very fast simulated annealing global inversion that fits the observations equally well, follow the equivalence principle and show a definite trend. For a thin conductive layer, the quotient between resistivity and thickness is constant, while for a resistive one, the product between these magnitudes is constant. Three approaches to obtain very fast simulated annealing solutions are tested. In the first one, layer resistivities and thicknesses are optimized in a linear domain. In the second, layer resistivities are optimized in the logarithmic domain and thicknesses in the linear domain. Lastly, both layer resistivities and thicknesses are optimized in the logarithmic domain. Only model data from the mean models, corresponding to very fast simulated annealing solutions obtained for approach three, always fit the observations. The mean model defined by multiple very fast simulated annealing solutions shows extremely large uncertainty (almost 100%) in the final solution after inversion of individual DC resistivity or electromagnetic (EM) data sets. Uncertainty associated with the intermediate resistive and conducting layers after global optimization and joint inversion is still large. In order to reduce the large uncertainty associated with the intermediate layer, global optimization is performed over several iterations by reducing and redefining the search limits of model parameters according to the uncertainty in the solution. The new minimum and maximum limits are obtained from the uncertainty in the previous iteration. Though the misfit error reduces in the solution after successive refinement of the model space in individual inversion, it is observed that the mean model drifts away from the actual model. However, successive refinement of the model space using global optimization and joint inversion reduces uncertainty to a very low level in 4-5 iterations. This approach works very well in resolving the problem of equivalence for resistive as well as for conducting layers. The efficacy of the approach has been demonstrated using DC resistivity and EM data, however, it can be applied to any geophysical data to solve the inherent ambiguities in the interpretations. © 2011 European Association of Geoscientists & Engineers.

Sarkar S.K.,Indian Institute of Technology Kharagpur
PloS one | Year: 2012

The combination of antibiotics is one of the strategies to combat drug-resistant bacteria, though only a handful of such combinations are in use, such as the β-lactam combinations. In the present study, the efficacy of a specific sub-inhibitory concentration of cefsulodin with other β-lactams was evaluated against a range of Gram-negative clinical isolates. This approach increased the sensitivity of the isolates, regardless of the β-lactamase production. The preferred target and mechanism of action of cefsulodin were identified in laboratory strains of Escherichia coli, by examining the effects of deleting the penicillin-binding protein (PBP) 1a and 1b encoding genes individually. Deletion of PBP1b was involved in sensitizing the bacteria to β-lactam agents, irrespective of its O-antigen status. Moreover, the use of a sub-inhibitory concentration of cefsulodin in combination with a β-lactam exerted an effect similar to that one obtained for PBP1b gene deletion. We conclude that the identified β-lactam/cefsulodin combination works by inhibiting PBP1b (at least partially) despite the involvement of β-lactamases, and therefore could be extended to a broad range of Gram-negative pathogens.

Dutta Majumdar J.,Indian Institute of Technology Kharagpur
Physics Procedia | Year: 2010

In the present study, a high power continuous wave CO2 laser has been used for development of titanium boride/diboride dispersed aluminium matrix composite on aluminium, a graded SiC dispersed α-Fe matrix composite on mild steel and TiN dispersed α-Ti matrix composite on Ti6Al4V. A detailed study of the microstructures and phases developed in the composite layer has been investigated and correlated with process parameters. A significant improvement in microhardness and wear resistance properties was recorded. The mechanism of properties improvement is discussed in detail.

Rao K.S.,Indian Institute of Technology Kharagpur
Computer Speech and Language | Year: 2010

The basic goal of the voice conversion system is to modify the speaker-specific characteristics, keeping the message and the environmental information contained in the speech signal intact. Speaker characteristics reflect in speech at different levels, such as, the shape of the glottal pulse (excitation source characteristics), the shape of the vocal tract (vocal tract system characteristics) and the long-term features (suprasegmental or prosodic characteristics). In this paper, we are proposing neural network models for developing mapping functions at each level. The features used for developing the mapping functions are extracted using pitch synchronous analysis. Pitch synchronous analysis provides the estimation of accurate vocal tract parameters, by analyzing the speech signal independently in each pitch period without influenced by the adjacent pitch cycles. In this work, the instants of significant excitation are used as pitch markers to perform the pitch synchronous analysis. The instants of significant excitation correspond to the instants of glottal closure (epochs) in the case of voiced speech, and to some random excitations like onset of burst in the case of nonvoiced speech. Instants of significant excitation are computed from the linear prediction (LP) residual of speech signals by using the property of average group-delay of minimum phase signals. In this paper, line spectral frequencies (LSFs) are used for representing the vocal tract characteristics, and for developing its associated mapping function. LP residual of the speech signal is viewed as excitation source, and the residual samples around the instant of glottal closure are used for mapping. Prosodic parameters at syllable and phrase levels are used for deriving the mapping function. Source and system level mapping functions are derived pitch synchronously, and the incorporation of target prosodic parameters is performed pitch synchronously using instants of significant excitation. The performance of the voice conversion system is evaluated using listening tests. The prediction accuracy of the mapping functions (neural network models) used at different levels in the proposed voice conversion system is further evaluated using objective measures such as deviation (D i), root mean square error (μ RMSE) and correlation coefficient (γ X, Y). The proposed approach (i.e., mapping and modification of parameters using pitch synchronous approach) used for voice conversion is shown to be performed better compared to the earlier method (mapping the vocal tract parameters using block processing) proposed by the author. © 2009 Elsevier Ltd. All rights reserved.

Deb K.,Indian Institute of Technology Kharagpur | Samadhiya N.K.,Indian Institute of Technology Roorkee | Namdeo J.B.,Indian Institute of Technology Roorkee
Geotextiles and Geomembranes | Year: 2011

Results from a series of laboratory model tests on unreinforced and geogrid-reinforced sand bed resting on stone column-improved soft clay have been presented. The diameter of stone column and footing has been taken as 50 mm and 100 mm, respectively for all the model tests carried out. Load was applied to the soil bed through the footing until the total settlement reached at least 20% of footing diameter. As compared to unimproved soft clay, the increase in load-carrying capacity under different improved ground conditions has been observed. Influences of the thickness of unreinforced as well as geogrid-reinforced sand bed and the size of geogrid reinforcement on the performance of stone column-improved soft clay bed have also been investigated. Significant improvement in load-carrying capacity of soft soil is observed due to the placement of sand bed over stone column-improved soft clay. The inclusion of geogrid layer within sand bed further increases the load-carrying capacity and decreases the settlement of the soil. Due to the placement of sand bed, the bulge diameter of stone column reduces while the depth of bulge increases. Further reduction in the bulge diameter and increase in bulge depth are observed due to application of geogrid layer. The optimum thickness of unreinforced sand bed is twice the optimum thickness of geogrid-reinforced sand bed. Under specific material properties and test conditions, it is further observed that the optimum diameter of geogrid layer is thrice the diameter of footing. © 2010 Elsevier Ltd.

Singh A.,Indian Institute of Technology Kharagpur
Journal of Hydrology | Year: 2014

The continuous increase in global population and simultaneous decrease in good quality water resources emphasizes the need of using surface water and groundwater resources conjunctively for irrigation. The conjunctive use allows the utilization of poor quality water, which cannot be used as such for the crop production due to its harmful effect on soil and crop health. This paper presents an overview on issues and methods of the conjunctive use of surface water and groundwater resources for sustainable irrigated agriculture. The background of the conjunctive water use and its applications for the management of poor quality water and management of rising watertable are presented. The management of conjunctive water use through the computer-based models is also covered in this review. The advantages and disadvantages of the approach have been described. Conclusions are provided based on this review which could be useful for all the stakeholders. © 2014 Elsevier B.V.

Singh A.,Indian Institute of Technology Kharagpur
Journal of Hydrology | Year: 2014

The coastal aquifers of the world are facing environmental problem of seawater intrusion. This problem is the results of indiscriminate and unplanned groundwater exploitation for fulfilling the growing need of freshwater for the burgeoning global population. There is a need to develop appropriate management models for assessing the maximum feasible pumping rates which protects seawater intrusion in coastal aquifers. The comprehensive reviews on the use of various programming techniques for the solution of seawater intrusion management problem of coastal aquifers have been provided in this paper. The literature review revealed that the management models used in the past mainly considered the objectives of maximization of pumping rate, minimization of drawdown, minimization of pumped water, minimization of seawater volume into the aquifer, and/or minimization of pumping cost. The past reviews are grouped into five sections based on the programming techniques adopted. The sections include: linear programming, nonlinear programming, genetic algorithms, artificial neural networks, and multiobjective optimization models. Conclusions are drawn where gaps exist and more research needs to be focused. This review provides the basis for the selection of appropriate methodology for the management of seawater intrusion problems of coastal aquifers. © 2013 Elsevier B.V.

Basak N.,National Institute of Technology Jalandhar | Jana A.K.,National Institute of Technology Jalandhar | Das D.,Indian Institute of Technology Kharagpur | Saikia D.,National Institute of Technology Jalandhar
International Journal of Hydrogen Energy | Year: 2014

Hydrogen is green fuel for the future, mainly due to its recyclability. Biohydrogen production processes are less energy intensive and environmental friendly in compared to chemical processes. Fermentative biohydrogen production can be broadly classified as: dark and photo fermentation. Two enzymes, nitrogenase and hydrogenase play important role in biohydrogen production. Purple Non-Sulfur bacteria (PNS) are mainly used in photofermentative hydrogen production through which the overall yield can be improved manifolds. The scope and objective of this review paper is to investigate the performance of various light driven photofermentative hydrogen production by PNS bacteria along with several developmental works related to batch, repeated batch, feed batch and continuous operation. However the study of Photobiological process by microalgae or cyanobacteria is outside the scope of this review. Optimization of suitable process parameters such as carbon and nitrogen ratio, illumination intensity, bioreactor configuration, immobilization of active cells in specific continuous mode and inoculum age may lead to higher yield of hydrogen generation. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Wagenmakers E.-J.,University of Amsterdam | Lodewyckx T.,Catholic University of Leuven | Kuriyal H.,Indian Institute of Technology Kharagpur | Grasman R.,University of Amsterdam
Cognitive Psychology | Year: 2010

In the field of cognitive psychology, the p-value hypothesis test has established a stranglehold on statistical reporting. This is unfortunate, as the p-value provides at best a rough estimate of the evidence that the data provide for the presence of an experimental effect. An alternative and arguably more appropriate measure of evidence is conveyed by a Bayesian hypothesis test, which prefers the model with the highest average likelihood. One of the main problems with this Bayesian hypothesis test, however, is that it often requires relatively sophisticated numerical methods for its computation. Here we draw attention to the Savage-Dickey density ratio method, a method that can be used to compute the result of a Bayesian hypothesis test for nested models and under certain plausible restrictions on the parameter priors. Practical examples demonstrate the method's validity, generality, and flexibility. © 2009 Elsevier Inc. All rights reserved.

Chakraborty S.,Indian Institute of Technology Kharagpur
IEEE Transactions on Wireless Communications | Year: 2016

The IEEE 802.11s wireless mesh networking standard supports power save mode where a mesh station can switch from the awake state to the doze state when there is no data to transmit. In the standard, the doze state is peer specific and has two different modes of operations - light sleep mode and deep sleep mode. This paper analytically evaluates the performance of a mesh basic service set under the operation of different power save modes, with the help of a queuing petri net modeling. The analytical model gives several insights of the power save mode operations, which are further validated using simulation results as well as results from a practical mesh networking testbed. Our analysis reveals that there exists interesting performance tradeoffs among light sleep mode and deep sleep mode, that can be explored to design an efficient power profile for mesh networks. © 2002-2012 IEEE.

Jana A.K.,Indian Institute of Technology Kharagpur
AIChE Journal | Year: 2015

Exploring an internal heat source through bottom flashing route, this work introduces a dynamic batch column configuration within the framework of mechanical heat pump system. This batch rectifier with bottom flashing (BRBF) scheme attempts to use the reboiler liquid as a heat exchanging medium in the overhead condenser, thereby avoiding the use of any external coolant stream and reducing the consumption of hot utility in the reboiler. Aiming to operate the proposed transient process unit at an optimal state of energy use, we formulate an online open-loop control policy that estimates the multiple control actions simultaneously. Furthermore, in order to achieve constant product purity, a gain-scheduled closed-loop control system is synthesized with keeping the stability margin constant. Simulating a multicomponent reactive system, the novel BRBF arrangement is evaluated in the aspects of energy savings and cost under both the open-loop and closed-loop control modes. © 2015 American Institute of Chemical Engineers.

Jana A.K.,Indian Institute of Technology Kharagpur
Applied Thermal Engineering | Year: 2015

Growing energy demand, depletion of fossil fuel resources and environmental concerns have stimulated intensive research in improving the energetic potential of well-established process units through process intensification route. In this contribution, a novel internal heat integration scheme is introduced for batch stripping. Aiming to improve the thermodynamic efficiency of this transient distillation column, the tower is proposed to primarily divide into two diabatic sections. The upper section (top stripper) is operated at elevated pressures (heat source) keeping the lower part (bottom stripper) at normal state (heat sink) so that there exists a thermal driving force between them. With this goal, the proposed heat integrated batch stripper (HIBS) additionally requires a couple of internal heat exchangers, a compressor and a pressure reducing throttling valve. To quantify the benefits achieved by this novel scheme over a conventional standalone column, we use three performance indexes, namely energy savings, total annualized cost and CO2 emissions. Finally, the proposed HIBS configuration is demonstrated by simulating a binary system of cyclohexane and toluene. © 2015 Elsevier Ltd. All rights reserved.

Ram M.,Indian Institute of Technology Kharagpur
Physica B: Condensed Matter | Year: 2010

Electrical properties of LiCo3/5Mn2/5VO4 are investigated using ac technique of complex impedance spectroscopy (CIS). Microstructure study of the sintered pellet reveals grains of unequal sizes (∼0.2-2 μm). Grain interior, grain boundary and electrode-material interface contributions to electrical response are identified by the analysis of complex plane diagrams. Variation of d.c. conductivity (σdc) with temperature indicates that the electrical conduction in the material is a thermally activated process. The value of activation energy computed from the Arrhenius plot of σdc and σgb with 103/T are ∼ (0.409±0.015) eV (27-275 °C) and ∼ (0.429±0.029) eV (27-275 °C), respectively. The scaling behavior of imaginary electric modulus shows the non-Debye type (polydispersive) conductivity relaxation in the material. © 2009 Elsevier B.V. All rights reserved.

Rout R.R.,National Institute of Technology Warangal | Ghosh S.K.,Indian Institute of Technology Kharagpur
Computer Communications | Year: 2014

In an energy-constraint wireless sensor network (WSN), the sensor nodes near the Sink deplete their energy quickly due to heavy traffic and create a bottleneck zone. In a large monitoring area, the sensor nodes in a cluster may communicate with the cluster head using multi-hop mode. A bottleneck effect can also be created near the cluster heads in a cluster based WSN with several clusters. The clustering technique (along with data aggregation) exploits the data correlation among the sensors' data and provides opportunities for reduction of energy consumption in WSN. Integrating an energy efficient scheme, namely, network coding, with clustering and duty cycling may facilitate the design of a new cluster based data collection scheme. This work proposes an energy efficient adaptive data aggregation strategy using network coding (ADANC) which improves the energy efficiency in a cluster based duty-cycled WSN. A set of nodes (one-hop away from the cluster head) act as network coder nodes and rest of the nodes act as simple relay nodes in a cluster. The network coder nodes also act as aggregation points, opportunistically, based on the level of data correlation. The proposed ADANC strategy provides reduction of traffic inside a cluster and thus improves the energy efficiency of the bottleneck zone. It has been shown that the packet delivery ratio improves with the proposed scheme in a cluster. The improvement in energy efficiency with ADANC scheme has been analyzed and the upper bound of network lifetime has been estimated. A detailed theoretical analysis has been performed for a cluster based duty cycled WSN. © 2013 Elsevier B.V. All rights reserved.

Dalai T.K.,Indian Institute of Technology Kharagpur | Ravizza G.,University of Hawaii at Manoa
Geochimica et Cosmochimica Acta | Year: 2010

Osmium isotope composition (187Os/188Os) and concentrations of Os, Ir and Pt are reported for an early Pleistocene section from the ODP Site 849 in the eastern equatorial Pacific. Using the data obtained in this study, the contributions from detrital and extraterrestrial particulate matter to Os concentration and 187Os/188Os of sediment are estimated. Our calculations show that detrital contributions to sedimentary Os are too small (<2%) to significantly shift measured bulk sediment 187Os/188Os away from seawater values. A moderate but significant negative correlation between 187Os/188Os and 3He/188Os indicate that the average particulate extraterrestrial Os flux to this site is 1.21±0.47pgcm2kyr1, which constitutes 3% of total Os burial flux. The estimates of detrital and extraterrestrial Os are used to calculate the seawater 187Os/188Os in the early Pleistocene. The most notable features of this early Pleistocene 187Os/188Os record are: (1) glacial-interglacial 187Os/188Os differences are insignificant within errors of estimates, (2) glacial 187Os/188Os values are higher compared to those reported for the late Pleistocene glacials. Comparison of 187Os/188Os values at Site 849 to the late Pleistocene records suggests that average seawater 187Os/188Os change has been modest (∼5%) since the early Pleistocene. Assuming that 187Os/188Os difference between the glacial periods of the late and the early Pleistocene results solely from temperature dependence of weathering rates, it has been calculated that average surface temperature during the late Pleistocene glacials was 0.8±0.2°C lower than glacials in the early Pleistocene. This inference is consistent with temperature estimates based on a recent study of pCO2 reconstruction in the Pleistocene. This observation based on limited studies of marine 187Os/188Os records seems to suggest that temperature played an important role in influencing chemical weathering during the Pleistocene glacials. However, more studies are needed to confirm if this temperature-weathering feedback was operational throughout the Pleistocene. A significant down core Ir-3He co-variation coupled with similar burial fluxes of Ir at Site 849 and at LL44 GPC-3 in the north Pacific point to the utility of Ir concentration as a point paleoflux tracer. However, a twofold difference in Ir burial fluxes between the eastern and the western equatorial Pacific suggests that calibration in space and time is required to use Ir concentration as a robust indicator of paleoflux through time. Significant co-variation of concentrations of Os and total alkenone during the glacials coupled with lighter δ13C of benthic foraminifera indicates that productivity and carbon burial played a dominant control on scavenging of Os at Site 849. In a broader context, this data set encourages future investigation of response of PGE behavior to paleoceanographic processes. © 2010 Elsevier Ltd.

Ram M.,Indian Institute of Technology Kharagpur
Physica B: Condensed Matter | Year: 2010

The LiNiVO4 has been prepared using solution-based chemical method. Dielectric and a.c. conductivity properties are studied using complex impedance spectroscopy (CIS) technique. Frequency dependence of dielectric constant (εr) and tangent loss (tan δ) at room temperature indicates a dispersive behavior at low frequencies. The variation of a.c. conductivity (σac) with frequency at different temperatures obeys the Jonscher's universal power law. © 2009 Elsevier B.V. All rights reserved.

Ram M.,Indian Institute of Technology Kharagpur
Journal of Alloys and Compounds | Year: 2011

The compound [Li(Ni7/10Fe3/10)VO4] was produced by a solution-based chemical route whose electrical properties were investigated using complex impedance spectroscopy technique. X-ray diffraction study reveals an orthorhombic unit cell structure of the compound. Complex electrical impedance analysis exhibits: (i) grain interior, grain boundary and electrode-material interface contributions to electrical response and (ii) the presence of temperature dependent electrical relaxation phenomena in the material. Electrical conductivity study indicates that electrical conduction in the material is a thermally activated process. © 2010 Elsevier B.V. All rights reserved.

Majumdar J.D.,Indian Institute of Technology Kharagpur
Physics Procedia | Year: 2011

The present study concerns in-depth analysis of the alloyed zone formed by laser gas alloying of Ti-6Al-4V by melting the surface using a continuous wave Diode laser using nitrogen shroud. A detailed structure-property-process parameters correlation has been undertaken to optimize the process parameters. The microstructure of the alloyed zone consists of dispersion of titanium nitrides in α-Ti matrix. The morphology and mass fraction of titanium nitride was found to vary with laser parameters (applied power and gas flow rate). Residual stress on the surface nitrided zone was found to vary with laser parameters, application of high power and low gas flow rate was found to be essential in reducing residual tensile stress. The microhardness and corrosion property of the alloyed zone were improved significantly as compared to as-received Ti-6Al-4V substrate. © 2011 Published by Elsevier Ltd.

Mukherjee J.,Indian Institute of Technology Kharagpur
Pattern Recognition Letters | Year: 2011

In this paper we discuss about some interesting properties of local rank transform and also about some possible applications of this transform such as in edge extraction and image enhancement. An interesting convergence property on the iterative application of this transform on a signal has also been proved in this work. © 2010 Elsevier B.V. All rights reserved.

Rao K.S.,Indian Institute of Technology Kharagpur
International Journal of Speech Technology | Year: 2011

In this paper we demonstrate the use of prosody models for developing speech systems in Indian languages. Duration and intonation models developed using feedforward neural networks are considered as prosody models. Labelled broadcast news data in the languages Hindi, Telugu, Tamil and Kannada is used for developing the neural network models for predicting the duration and intonation. The features representing the positional, contextual and phonological constraints are used for developing the prosody models. In this paper, the use of prosody models is illustrated using speech recognition, speech synthesis, speaker recognition and language identification applications. Autoassociative neural networks and support vector machines are used as classification models for developing the speech systems. The performance of the speech systems has shown to be improved by combining the prosodic features along with one popular spectral feature set consisting of Weighted Linear Prediction Cepstral Coefficients (WLPCCs). © 2010 Springer Science+Business Media, LLC.

Bag S.,Indian Institute of Technology Kharagpur | Harit G.,Indian Institute of Technology Jodhpur
Pattern Recognition Letters | Year: 2011

Digital skeleton of character images, generated by thinning method, has a wide range of applications for shape analysis and classification. But thinning of character images is a big challenge. Removal of spurious strokes or deformities in thinning is a difficult problem. In this paper, we propose a contour-based thinning method used for performing skeletonization of printed noisy isolated character images. In this method, we use shape characteristics of text to get skeleton of nearly same as the true character shape. This approach helps to preserve the local features and true shapes of the character images. As a by-product of our thinning approach, the skeleton also gets segmented into strokes in vector form. Hence further stroke segmentation is not required. Experiment is done on printed English, Bengali, Hindi, and Tamil characters and we obtain much better results comparing with other thinning methods without any post-processing. © 2011 Elsevier B.V. All rights reserved.

Mishra D.P.,Indian School of Mines | Das S.K.,Indian Institute of Technology Kharagpur
Materials Characterization | Year: 2010

This study examines the suitability of Talcher coal fly ash for stowing in the nearby underground coal mines based on their physico-chemical and mineralogical analysis. The physical properties such as bulk density, specific gravity, particle size distribution, porosity, permeability and water holding capacity etc. have been determined. From the chemical characterization it is found that the ash samples are enriched predominantly in silica (SiO 2), alumina (Al 2O 3) and iron oxides (Fe 2O 3), along with a little amount of CaO, and fall under the Class F fly ash category. In addition, the mineral phases identified in the ash samples are quartz, mullite, magnetite, and hematite. The particle morphological analysis revealed that the ash particles are almost spherical in shape and the bulk ash porous in nature. From the particle size and permeability point of view, pond ash may be considered a better stowing material than fly ash. © 2010 Elsevier Inc.

Bandopadhyay A.,Advanced Technology Development Center | Chakraborty S.,Advanced Technology Development Center | Chakraborty S.,Indian Institute of Technology Kharagpur
Electrophoresis | Year: 2013

Electrokinetics in salt-free media (in which counterions are only present) is central to the performance of many systems of modern technological relevance, ranging from ion-selective nanopores to electronic papers. Here, we introduce an analytical theory to describe the size dependence of electroosmosis in such typical scenarios, exhibiting an interesting confluence of the implications of interdependence of the electroosmotic transport mechanisms, ionic sizes, and confinement dimensions along with the counterion concentration. Our results do reveal that the concerned mobility parameter, describing the strength of electroosmotic transport, increases simultaneously with increments in the surface charge density as well as an ionic size factor (also known as the steric factor), bearing far-ranging consequences in microfluidic and nanofluidic technology. © 2013 WILEY-VCH Verlag GmbH & Co.

DuttaMajumdar J.,Indian Institute of Technology Kharagpur | Li L.,University of Manchester
Materials Letters | Year: 2010

The present study aims at development of TiB dispersed α-Ti matrix composite by laser melting of Ti-2 wt.% B alloy powder (of particle size ranging from 50-100 μm) using a high power diode laser with argon shroud and depositing the molten alloy on a Ti-6Al-4 V substrate in a layer by layer fashion (up to a maximum of 5 layers were built). Followed by direct laser cladding, the characteristics and mechanical properties of the clad layer were investigated in details. Laser cladding led to formation of TiB dispersed α-Ti matrix composite with an average microhardness of 290 VHN to 500 VHN for different conditions of lasing. The average Young's modulus was considerably improved to 155-165 GPa. © 2009 Elsevier B.V. All rights reserved.

Roy J.N.,Indian Institute of Technology Kharagpur
Solar Energy | Year: 2015

Dry and wet insulation characteristics of a Solar Photovoltaic (SPV) module have been studied through theoretical modelling supported by experimental results. A new equivalent circuit model approach has been used to understand the effect of resistances of the individual material used in the SPV module and the overall impact on the insulation characteristics. The electrical resistances of all the individual material have also been measured separately prior to lamination. It has been seen that, post lamination, the characteristics change significantly. EVA (Ethyl Vinyl Acetate) and Back-sheet (Tedlar) looses their separate identity and exhibit properties of a different new combined material. The resistance of this material has been determined using the equivalent circuit modelling approach. It has been shown that the insulation behaviour is primarily governed by this material. The temperature characteristics of the insulation leakage currents follow Arrhenius behaviour with well defined activation energies. It has been determined from the activation energies that the primary leakage path is from cell to EVA-Tedlar to frame of the module. © 2015 Elsevier Ltd.

Ram M.,Indian Institute of Technology Kharagpur
Physica B: Condensed Matter | Year: 2010

The LiFe1/2Mn1/2VO4 compound was prepared by a standard solid-state reaction technique. The dielectric and electrical conductivity behavior of the compound over a wide frequency range (100 Hz-1 MHz) at temperatures (25-475 °C) was studied by complex impedance spectroscopy (CIS) technique. Studies of frequency and temperature dependence of dielectric constant and tangent loss of LiFe1/2Mn1/2VO4 exhibit a dispersive behavior at low frequencies. The variation of a.c. conductivity as a function of frequency at some selected temperatures obeys Jonscher's universal power law governed by the relation [σ (ω) = σd . c . + A ωn]. © 2010 Elsevier B.V. All rights reserved.

Sinha S.,Tata Consultancy Services Ltd. | Sarmah S.P.,Indian Institute of Technology Kharagpur
Computers and Industrial Engineering | Year: 2010

In this paper, a single-vendor multi-buyer discount pricing model has been developed under stochastic demand information. The vendor offers multiple pricing schedules to encourage the buyers to adopt the global optimal policy instead of their individual optimal ordering policy. The global optimal solution ensures that each buyer is assigned to the best schedule with maximum benefit. The results show that coordination benefit increases with increase in the number of pricing schedules. However, the system performance deteriorates with increasing demand variability and service level. Hence, if the system contains high degree of uncertainty or each buyer sets her service level too high, coordination through discount policy may not be an efficient mechanism to enhance channel profitability. © 2010 Elsevier Ltd. All rights reserved.

Ram M.,Indian Institute of Technology Kharagpur
Journal of Alloys and Compounds | Year: 2011

In the present work, an evaluation of the structural and electrical properties of a compound (LiZnVO4) has been undertaken. This compound was prepared by solution-based chemical route. The electrical properties were measured using a.c. impedance spectroscopy method in the frequency range of 103-106 Hz at various temperatures from 28 to 300 °C. X-ray diffraction study indicates a rhombohedral unit cell structure with lattice parameters a = 14.1934, b = 14.1934, c = 9.4926, V = 1656.12 () 3, α = 90° β = 90° and γ = 120°. A field emission scanning electron micrograph reveals a polycrystalline texture of the compound with grains of unequal sizes ∼0.2-2.0 μm. The electrical conduction in the material is a thermally activated process due to the bulk effect. Frequency dependence of a.c. conductivity obeys Jonscher's universal law (σac = σdc + Aωn). © 2011 Elsevier B.V. All rights reserved.

Geerlings P.,Vrije Universiteit Brussel | Ayers P.W.,McMaster University | Toro-Labbe A.,University of Santiago de Chile | Chattaraj P.K.,Indian Institute of Technology Kharagpur | De Proft F.,Vrije Universiteit Brussel
Accounts of Chemical Research | Year: 2012

In an attempt to master the overwhelming amount of data on the properties of substances and their reactions, chemists scrutinize them for underlying common patterns. In modern times quantum mechanics (QM) has played a leading role in the understanding of chemical reactivity. In the late 1960s, Woodward and Hoffmann (WH) proposed one of the most successful and elegant approaches to interpret the outcome of an important type of reaction: they could predict the allowed or forbidden character of pericyclic reactions through inspection of the phase and symmetry of the orbitals of the reactants obtained by simple extended Hückel theory. Today much more powerful computational techniques, such as density functional theory (DFT), are available that yield highly accurate results even for large systems. By focusing on the electron density, Ï(r), a fundamental carrier of information compared with the much more complicated wave function in conventional QM, DFT became the computational workhorse for systems of ever increasing complexity. However, the need for the interpretation of computational (and obviously experimental) results remains, and conceptual DFT has provided the answer to this challenge within the context of DFT. This branch of DFT has given precision to chemical concepts such as electronegativity, hardness, and softness and has embedded them in a perturbational approach to chemical reactivity. Previously, researchers have successfully applied conceptual DFT to generalized acid-base and, more recently, to radical and redox reactions. In this Account, we present a conceptual DFT ansatz for pericyclic reactions, a stringent test for this density-only approach, because the density has trivial symmetry and no phase.A density response function is the key quantity in a first approach: the dual descriptor f (2)(r), the second derivative of the electron density with respect to the number of electrons. Overlapping regions of the dual descriptor of the reactant(s) with different or the same sign yield pictorial representations similar to the orbital phase and symmetry-based pictures in the WH formulation. In a second approach, a key quantity is the evolution of the chemical hardness at the onset of the reaction. This quantity makes contact with Zimmerman's alternative approach to the WH rules based on the aromaticity of the transition state. Using the dual descriptor and the initial hardness response, we reinterpret the WH results for the four types of pericyclic reactions (cycloadditions, electrocyclizations, and sigmatropic and chelotropic reactions), both thermodynamically and photochemically. We demonstrate that these two approaches, which require only simple quantum chemical procedures (overlapping densities and HOMO-LUMO gap type calculations along a few points of a model reaction coordinate), are intimately related through a relation that converts the local (i.e., position-dependent) dual descriptor into the global (i.e., position-independent) (initial) hardness response. Our results show that with a density-only based approach the WH rules can be reinterpreted, pointing to the fundamental importance of the electron density as carrier of information as highlighted in the basic theorems of DFT. © 2012 American Chemical Society.

Chakraborty M.,Indian Institute of Technology Kharagpur
IEEE Transactions on Instrumentation and Measurement | Year: 2010

In this paper, we propose a new adaptive filter for estimating and tracking the delay and the relative amplitude of a sinusoid vis-a-vis a reference sinusoid of the same frequency. By careful choice of the sampling period, a two-tap finite-impulse response (FIR) filter model is constructed for the delayed signal. The delay and the amplitude are estimated by identifying the FIR filter for which a delay variable and an amplitude variable are updated in an LMS-like manner, deploying, however, separate step sizes. Convergence analysis proving convergence (in mean) of the delay and the amplitude updates to their respective true values is provided, and necessary convergence conditions are established. Stability regions in the step-size plane are also identified that guarantee bounded steady-state error variance for the delay and the amplitude estimates. The proposed method is computationally simple as the primary computation is a rotation of a vector that can efficiently be implemented using CORDIC processors. MATLAB-based simulation studies confirm satisfactory estimation performance of the proposed algorithm. © 2010 IEEE.

Jana A.K.,Indian Institute of Technology Kharagpur
IEEE Transactions on Industrial Informatics | Year: 2010

A nonlinear feedback linearizing control (FLC) strategy is proposed within the differential geometric framework for temperature control of a refinery debutanizer column. The distillation model is verified by real data. The FLC control algorithm usually consists of a transformer, a state estimator and an external linear controller. Here, two state estimators, namely extended Kalman filter (EKF) and short-cut model-based open-loop estimator (SMBOLE), have been developed to device the hybrid FLC-EKF and FLC-SMBOLE control systems, respectively. In order to avoid estimator design complexity as well as computational burden, an ideal binary distillation model [light key (LK)/heavy key (HK)] has been used as an EKF predictor and open-loop estimator (OLE). In this article, a comparative study has been conducted between the FLC-EKF, FLC-SMBOLE and a classical dual-loop proportional integral derivative (PID) control structure. Simulation results show that despite the significant process/model mismatch, the proposed FLC controllers perform better than the PID control scheme. © 2009 IEEE.

Mukherjee R.,Indian Institute of Technology Kharagpur | Sharma A.,Indian Institute of Technology Kanpur
Soft Matter | Year: 2015

The free surface of a thin soft polymer film is often found to become unstable and self-organizes into various meso-scale structures. In this article we classify the instability of a thin polymer film into three broad categories, which are: category 1: instability of an ultra-thin (<100 nm) viscous film engendered by amplification of thermally excited surface capillary waves due to interfacial dispersive van der Waals forces; category 2: instability arising from the attractive inter-surface interactions between the free surface of a soft film exhibiting room temperature elasticity and another rigid surface in its contact proximity; and category 3: instability caused by an externally applied field such as an electric field or a thermal gradient, observed in both viscous and elastic films. We review the salient features of each instability class and highlight how characteristic length scales, feature morphologies, evolution pathways, etc. depend on initial properties such as film thickness, visco-elasticity (rheology), residual stress, and film preparation conditions. We emphasize various possible strategies for aligning and ordering of the otherwise isotropic structures by combining the essential concepts of bottom-up and top-down approaches. A perspective, including a possible future direction of research, novelty and limitations of the methods, particularly in comparison to the existing patterning techniques, is also presented for each setting. © The Royal Society of Chemistry.

Singh A.,Indian Institute of Technology Kharagpur
Agricultural Water Management | Year: 2014

Good quality surface water and groundwater resources are limited furthermore they are shrinking because of the urbanization, contamination, and climate change impacts. In this backdrop, the proper allocation and management of these resources is a critical challenge for satisfying the rising water demands of agricultural sector. Because irrigated agriculture is the largest user of all the developed water resources and consumes over 70% of the abstracted freshwater globally. The computer-based models are useful tools for achieving the optimal allocation of limited water resources for the conjunctive use planning and management in irrigated agriculture. Various simulation and optimization modeling approaches have been used to solve the water allocation problems. Optimization models have been shown to be of great importance when used with simulation models and the combined use of these two approaches gives the best results. The reviews on the combined applications of simulation and optimization modeling for the conjunctive use planning and management of surface water and groundwater resources for sustainable irrigated agriculture are done and presented in this paper. Conclusions are provided based on this review which could be useful for all the stakeholders. © 2014 Elsevier B.V.

Ray S.,Indian Institute of Technology Kharagpur
Journal of Vertebrate Paleontology | Year: 2015

A large traversodontid cynodont Ruberodon roychowdhurii, gen et. sp. nov., is described from the Late Triassic Tiki Formation of the Rewa Gondwana Basin, India, based on an ontogenetic series of five partial lower jaws. Ruberodon is characterized by a robust and deep dentary symphysis, lower dental formula of i3-c1-pc9, procumbent and hypertrophied first lower incisor, a large canine, long diastema between the lower canine and first postcanine, and a high coronoid process at 60°to the horizontal tooth row. With growth, the symphyseal region became relatively more slender with lengthening of the diastema. Phylogenetic analysis based on 19 taxa and 35 craniodental characters places Ruberodon within the clade containing Gomphodontosuchus, Menadon, Protuberum, Scalenodontoides, and the multispecific Exaeretodon. The new genus forms a sister taxon to E. statisticae and is more advanced than E. riograndensis and E. argentinus based on the presence of a strong coronoid ridge anterior to the masseteric fossa. Based on its tetrapod assemblage, the Tiki Formation may be globally correlated with other formations such as the lower part of the Maleri Formation of India, the Isalo II Beds of Madagascar, and the upper part of the Santa Maria Formation of Brazil. An early Carnian age is proposed for the Tiki Formation. © 2015 by the Society of Vertebrate Paleontology.

Singh A.,Indian Institute of Technology Kharagpur
Journal of Hydrologic Engineering | Year: 2014

This study presents the formulation and application of a linear programming model for the maximization of net annual farm income from an area located in the Rohtak district of Haryana, India. A groundwater balance constraint was imposed on the model, which mitigates the waterlogging problem of the area, while making an optimal allocation of land and water resources. The model results showed a reduction in rice, gram, barley, and mustard areas against an increase in wheat, cotton, and sugarcane under optimal conditions. Under the optimal land and water allocation, groundwater use is increased while canal allocation is decreased. The net annual farm income from the command area has increased by about 26% under optimal allocations. The sensitivity analysis of the model parameters showed that a better price of crops is the most sensitive parameter, followed by the crop area and cost of cultivation. State agencies and farmers involved in the actual agricultural production process are advised to practice conjunctive use of canal water and groundwater for maximizing their farm income. This strategy would also mitigate hydrological imbalances in the groundwater system without installing expensive drainage systems, which is not feasible because the groundwater quality is poor and drainage water may pose a serious disposal problem. © 2014 American Society of Civil Engineers.

Berry M.V.,H H Wills Physics Laboratory | Shukla P.,Indian Institute of Technology Kharagpur
Journal of Physics A: Mathematical and Theoretical | Year: 2010

Weak values, resulting from the action of an operator on a preselected state when measured after postselection by a different state, can lie outside the spectrum of eigenvalues of the operator: they can be 'superweak'. This phenomenon can be quantified by averaging over an ensemble of the two states, and calculating the probability distribution of the weak values. If there are many eigenvalues, distributed within a finite range, this distribution takes a simple universal generalized lorentzian form, and the 'superweak probablility', of weak values outside the spectrum, can be as large as 1-1/√2 = 0.293.... By contrast, the familiar expectation values always lie within the spectral range, and their distribution, although approximately gaussian for many eigenvalues, is not universal. © 2010 IOP Publishing Ltd.

Marchang N.,North Eastern Regional Institute of Science and Technology | Datta R.,Indian Institute of Technology Kharagpur
IET Information Security | Year: 2012

Mobile ad hoc networks (MANETs) were originally designed for a cooperative environment. To use them in hostile environments, trust-based routing can be used, where instead of establishing the shortest routes as done in traditional routing protocols, most trusted routes are established. In this study, the authors present a light-weight trust-based routing protocol. It is light-weight in the sense that the intrusion detection system (IDS) used for estimating the trust that one node has for another, consumes limited computational resource. Moreover, it uses only local information thereby ensuring scalability. Our light-weight IDS takes care of two kinds of attacks, namely, the blackhole attack and the grey hole attack. Whereas our proposed approach can be incorporated in any routing protocol, the authors have used AODV as the base routing protocol to evaluate our proposed approach and give a performance analysis. © 2012 The Institution of Engineering and Technology.

Roy P.,Birla Institute of Technology | Srivastava S.K.,Indian Institute of Technology Kharagpur
CrystEngComm | Year: 2015

Among different metal chalcogenides, copper sulfides have been extensively studied in the past few years due to their semiconducting and non-toxic nature, making them useful in a wide range of applications from the energy to the biomedical fields. A series of stoichiometric compositions of copper sulfides from Cu-rich, Cu2S to Cu-deficient, CuS2 exist with different crystal structures as well as phases, resulting in different unique properties. The suitable band gap values in the range of 1.2-1.5 eV and unique optoelectronic properties indicate that the material is photocatalytically active and exhibits excellent plasmonic behavior. The material is also known for promising thermoelectric properties, converting waste heat into electricity through the Seebeck effect. The nanodimensional form of copper sulfides promotes their use to a more advanced level, tuning their properties with the size of the materials. In view of this, the present review article is focused on the compositions, phases and crystal structures, and different synthetic methodologies involved in the fabrication of 0D, 1D and 2D nanostructured copper sulfides. Moreover, recent advancements on their use in various applications will also be briefly discussed. © 2015 The Royal Society of Chemistry.

Martis R.J.,Indian Institute of Technology Kharagpur
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011

Electrocardiogram (ECG) is the P-QRS-T wave which indicates the electrical activity of the heart. The subtle changes in the amplitude and duration of the ECG signal depict the cardiac abnormality. It is very difficult to decipher these minute changes by the naked eye. Hence, a computer-aided diagnosis system will help the physicians to monitor the cardiac health. The ECG is a nonlinear and non-stationary signal. Hence, the hidden information in the ECG signal can be extracted using nonlinear method. In this paper, we have automatically classified normal and abnormal beats using higher order spectra (HOS) cumulants of wavelet packet decomposition (WPD). The abnormal beats are ventricular premature contractions (VPC) and Atrial premature contractions (APC). These HOS cumulant features of the WPD are subjected to principal component analysis (PCA) to reduce the number of features to five. Finally these features were fed to the support vector machine (SVM) with kernel functions for automatic classification. In our work, we have obtained the highest accuracy of 98.4% sensitivity and specificity of 98.9% and 98.0% respectively with radial basis function (RBF) kernel function and Meyer's wavelet (dmey) function. Our system is ready clinically to run on large amount of data sets.

Bharti R.,Indian Institute of Technology Kharagpur
Oncogene | Year: 2015

Interleukin-6 (IL-6) signaling network has been implicated in oncogenic transformations making it attractive target for the discovery of novel cancer therapeutics. In this study, potent antiproliferative and apoptotic effect of diacerein were observed against breast cancer. In vitro apoptosis was induced by this drug in breast cancer cells as verified by increased sub-G1 population, LIVE/DEAD assay, cell cytotoxicity and presence of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, as well as downregulation of antiapoptotic proteins Bcl-2 and Bcl-xL and upregulation of apoptotic protein Bax. In addition, apoptosis induction was found to be caspase dependent. Further molecular investigations indicated that diacerein instigated apoptosis was associated with inhibition of IL-6/IL-6R autocrine signaling axis. Suppression of STAT3, MAPK and Akt pathways were also observed as a consequence of diacerein-mediated upstream inhibition of IL-6/IL-6R. Fluorescence study and western blot analysis revealed cytosolic accumulation of STAT3 in diacerein-treated cells. The docking study showed diacerein/IL-6R interaction that was further validated by competitive binding assay and isothermal titration calorimetry. Most interestingly, it was found that diacerein considerably suppressed tumor growth in MDA-MB-231 xenograft model. The in vivo antitumor effect was correlated with decreased proliferation (Ki-67), increased apoptosis (TUNEL) and inhibition of IL-6/IL-6R-mediated STAT3, MAPK and Akt pathway in tumor remnants. Taken together, diacerein offered a novel blueprint for cancer therapy by hampering IL-6/IL-6R/STAT3/MAPK/Akt network.Oncogene advance online publication, 30 November 2015; doi:10.1038/onc.2015.466. © 2015 Macmillan Publishers Limited

Biligiri K.P.,Indian Institute of Technology Kharagpur
Transportation Research Part D: Transport and Environment | Year: 2016

Several studies have successfully developed laboratory and field measurement techniques to estimate tyre/road noise damping characteristics. However, laboratory-field noise correlations of pavement types in the form of nomographs is essential to cognize the pavements' acoustical properties from a practical perspective. A toolkit that readily provides field tyre/road noise intensity of different pavement materials is needed. Thus, the main objective of this study was to develop nomographs with relationships for tyre/road noise versus pavement materials' viscoelastic-vibroacoustical properties. Isothermal and isochronal nomographs of phase angle-tyre/road noise as toolkits were developed based upon well-established phase angle and noise intensities typical of mixtures, making the nomograph correlations very authentic, realistic, and novel along with benefit to predict tyre/road noise at any desired temperature and traffic speed (or frequency) combination. This study is envisaged to benefit in the discernment of road materials' damping capabilities from vibroacoustical and field noise-viscoelastic relation aspects. © 2015 Elsevier Ltd.

Rahut D.B.,Wheat Improvement Center | Behera B.,Indian Institute of Technology Kharagpur | Ali A.,Agricultural Economist
Renewable and Sustainable Energy Reviews | Year: 2016

This paper uses data from three Bhutan Living Standard surveys (BLSS 2003, BLSS 2007, and BLSS 2012) to examine the trends and patterns of household energy consumption, and identify and analyze the factors that influence household energy choices, consumption intensity and the per capita household expenditure on energy sources in Bhutan. During the last decade significant numbers of Bhutanese households have switched to cleaner energy sources. Empirical results show that a household's choice of cleaner energy sources is driven by income level and household wealth, the age, gender and education of the household heads, access to electricity, and location. Education and income have a differential role on the choice of clean or dirty fuel; wealthier and more educated households use and rely more on clean sources of energy like electricity and liquid petroleum gas while poorer households use and rely on dirty fuel such as fuelwood and kerosene. The study shows that female-headed households are more likely to choose cleaner fuels and, above all, the availability of a clean and cost-effective source of energy within proximity to the household is an important factor in the adoption of clean energy. Several models using a variety of alternative independent variables, such as proxies for education and wealth, were estimated and confirmed the robustness of the results. © 2015 Elsevier Ltd. All rights reserved.

Dhar A.,Indian Institute of Technology Kharagpur
ISH Journal of Hydraulic Engineering | Year: 2013

A methodology is developed based on the optimisation model and the geostatistical kriging model for the optimal design of groundwater head and quality monitoring plan. The multi-objective optimisation model considers minimisation of hydraulic head and concentration estimation error under budgetary limitation. The methodology incorporates Kriging as the external model for spatial estimation of hydraulic head and concentration values. Performances of the proposed model are evaluated for a regional groundwater aquifer in the Kanpur area. Multi-objective solution sets show directional preference along the hydraulic gradient. Performance evaluation results demonstrate the potential applicability of the methodology for optimal groundwater head and concentration monitoring plan design. © 2013 Indian Society for Hydraulics.

Ahmed R.,University of Bristol | Patra S.K.,University of Bristol | Patra S.K.,Indian Institute of Technology Kharagpur | Hamley I.W.,University of Reading | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

The use of ionic self-assembly, a facile non-covalent approach, to access non-conventional block copolymer morphologies, including tetragonal and helical structures, from a combination of polyferrocenylsilane diblock copolymer polyelectrolytes and AOT-based surfactants, is described. © 2013 American Chemical Society.

Bhargava V.,Indian Institute of Technology Kharagpur | Fateen S.E.K.,Cairo University | Bonilla-Petriciolet A.,Aguascalientes Institute of Technology
Fluid Phase Equilibria | Year: 2013

In this study, Cuckoo Search is introduced for performing phase equilibrium and stability calculations for the first time. Cuckoo Search is a population-based method that mimics the reproduction strategy of cuckoos. This meta-heuristics have been successfully used for solving some engineering design and optimization problems with promising results. However, this emerging optimization method has not been applied in chemical engineering problems including thermodynamic calculations. This study reports the application of Cuckoo Search and its modified version for phase equilibrium and stability calculations in both reactive and non-reactive systems. Performance of this nature-inspired optimization method has been analyzed using several phase stability, phase equilibrium and reactive phase equilibrium problems. Results show that Cuckoo Search offers a reliable performance for solving these thermodynamic calculations and is better than other meta-heuristics previously applied in phase equilibrium modeling. © 2012 Elsevier B.V.

Gupta A.,Indian Institute of Technology Kharagpur | O'Malley M.K.,Rice University
Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME | Year: 2011

In this paper, we propose the use of a nonlinear disturbance-observer for estimation of contact forces during haptic interactions. Most commonly used impedance-type haptic interfaces employ open-loop force control under the assumption of pseudostatic interactions. Advanced force control in such interfaces can increase simulation fidelity through improvement of the transparency of the device. However, closed-loop force feedback is limited both due to the bandwidth limitations of force sensing and the associated cost of force sensors required for its implementation. Using a disturbance-observer, we estimate contact forces at the tool tip, then use these estimates for closed-loop control of the haptic interface. Simulation and experimental results, utilizing a custom single degree-of-freedom haptic interface, are presented to demonstrate the efficacy of the proposed disturbance-observer (DO)-based control approach. This approach circumvents the traditional drawbacks of force sensing while exhibiting the advantages of closed-loop force control in haptic devices. Results show that the proposed disturbance-observer can reliably estimate contact forces at the human-robot interface. The DO-based control approach is experimentally shown to improve haptic interface fidelity over a purely open-loop display while maintaining stable and vibration-free interactions between the human user and virtual environment. Copyright © 2011 by ASME.

Singh A.,Indian Institute of Technology Kharagpur
Journal of Hydrology | Year: 2013

Rise in groundwater level followed by waterlogging and secondary salinisation has become a serious problem in canal irrigated areas located in arid and semi-arid regions of the world. To solve the problem, the groundwater model SGMP was applied in a waterlogged area of Haryana State of India in which about 500,000. ha has already waterlogged resulting in reduced crop yield and abandonment of agricultural lands. After successful calibration and validation, several scenario building exercises have been conducted. Error and sensitivity analyses of the model parameters were done. The impact of potential policy changes on the groundwater levels has been analysed through the model. The alternative scenarios revealed that small increase in the net recharge would cause the waterlogging problem to aggravate. On the other hand, if net recharge decreases, the situation would turn favorable. The study also revealed that by reducing the recharge in the range of 5-20% from the average values, the watertable could be stabilized at a safe depth. To prevent the area from further salinisation some recommendations can be given such as; increase in groundwater abstraction, water distribution as per water requirements of crops, and the lining of surface irrigation systems. Thus it is apparent that the SGMP model seems to be an effective tool for groundwater simulation. It has the potential of assessing the watertable behaviour due to various interventions. The results of simulation studies of existing and proposed water management policy, therefore, may form the basis for the identification of appropriate water management plans for the future. © 2013 Elsevier B.V.

Raul S.K.,Anand Agricultural University | Panda S.N.,Indian Institute of Technology Kharagpur
Water Resources Management | Year: 2013

The canal water supply, which is the only source of irrigation, in the rice-dominated cropping system of the Hirakud canal command (eastern India) is able to meet only 54 % of the irrigation demand at 90 % probability of exceedance. Hence, considering groundwater as the supplemental source of irrigation, conjunctive use management study by combined simulation-optimization modelling was undertaken in order to predict the maximum permissible groundwater pumpage from the command area. Further, optimal land and water resources allocation model was developed to determine the optimal cropping pattern for maximizing net annual return. The modelling results suggested that 2. 0 and 2. 3 million m3 of groundwater can be pumped from the bottom aquifer during monsoon and non-monsoon seasons, respectively, at 90 % probability of exceedance of rainfall and canal water availability (PERC). Optimal cropping patterns and pumping strategies can lead to about 51. 3-12. 5 % increase in net annual return from the area at 10-90 % PERC. The sensitivity analysis of the model indicates that the variation in the market price of crops has very high influence on the optimal solution followed by the cost of cultivation and cultivable area. Finally, different future scenarios of land and water use were formulated for the command area. The adoption of optimal cropping patterns and optimal pumping strategies is strongly recommended for sustainable management of available land and water resources of the canal command under hydrological uncertainties. © 2013 Springer Science+Business Media Dordrecht.

Sahoo B.,Indian Institute of Technology Kharagpur
Water Resources Management | Year: 2013

To implicitly model the nonlinear dynamics of flood wave propagation in rivers with floodplains, a multilinear discharge-hydrograph routing method based on time distribution scheme is proposed. The framework of this method is based on the variable parameter Muskingum-type routing method, which is used as the linear sub-model. The applicability limit and suitability of this flood routing method is verified using numerical experiments and field data, respectively. © 2012 Springer Science+Business Media Dordrecht.

Singh A.,Indian Institute of Technology Kharagpur
Land Use Policy | Year: 2016

Rise in groundwater level followed by waterlogging and secondary salinisation has become a serious problem in canal irrigated areas of arid and semiarid regions of the world. A wide range of solutions could be considered to address the problems. But the effectiveness of all the solutions and their combinations cannot be verified with on-farm experiments. Simulation models by way of their predictive capability are often the only viable means of providing input to policy decisions. To combat the problem, the computer based simulation model, SaltMod was applied in a waterlogged area of northwest India in which over 500,000 ha has already waterlogged resulting in reduced crop yield and abandonment of agricultural lands. After successful calibration and validation, several alternative management policies were studied for their long-term impacts on groundwater levels and salinities. The alternative policies revealed that the groundwater levels in the study area would continue to rise in the long-run under the existing conditions. Thus, suitable water management strategies such as changes in cropping patterns with reduced rice area, reduced canal water use, increased groundwater use, and canal lining are suggested to bring the groundwater level down to a safe depth and to prevent further rising of the groundwater level. © 2016 Elsevier Ltd.

Panigrahi K.L.,Indian Institute of Technology Kharagpur | Roy S.,Saha Institute of Nuclear Physics
Journal of High Energy Physics | Year: 2010

We apply the standard technique of Null Melvin Twist to the non-extremal (D1, D3) bound state configuration of type IIB string theory. Under a particular decoupling limit, such configuration represents the gravity dual of the non-relativistic, noncommutativeYang-Mills theory at a finite temperature. We then use the AdS/CFT and the string probe approach to compute the drag force on an external quark moving through such a hot non-relativistic, non-commutative YM plasma. We discuss various limiting cases to show the interplay between the non-relativistic as well as the non-commutative effect of the general drag force expression. © SISSA 2010.

Mejia C.A.,University of Southern California | Dutt A.,Indian Institute of Technology Kharagpur | Povinelli M.L.,University of Southern California
Optics Express | Year: 2011

We explore a technique which we term light-assisted templated self-assembly. We calculate the optical forces on colloidal particles over a photonic crystal slab. We show that exciting a guided resonance mode of the slab yields a resonantly-enhanced, attractive optical force. We calculate the lateral optical forces above the slab and predict that stably trapped periodic patterns of particles are dependent on wavelength and polarization. Tuning the wavelength or polarization of the light source may thus allow the formation and reconfiguration of patterns. We expect that this technique may be used to design all-optically reconfigurable photonic devices. ©2011 Optical Society of America.

INTRODUCTION: In addition to reducing Haemophilus influenzae type b (Hib) disease in vaccinated individuals, the Hib conjugate vaccine (HibCV) has indirect effects; it reduces Hib disease in unvaccinated individuals by decreasing carriage. HIV infected children are at increased risk for Hib disease and live in families where multiple members may have HIV. OBJECTIVE: To look at the impact of 2 doses of the HibCV on nasopharyngeal carriage of Hib in HIV infected Indian children (2-15 years) and the indirect impact on carriage in their parents. METHODS: This prospective cohort study was conducted in HIV infected and uninfected families. Nasopharyngeal swabs were collected from children and parents before and after vaccination. HIV infected children ages 2-15 years got two doses of HibCV and were followed up for 20 months. Uninfected children age 2-5 years got 1 dose of HibCV as catch-up. RESULTS: 123 HIV infected and 44 HIV uninfected children participated. Baseline colonization in HIV infected children was13.8% and dropped to 1.8% (p=0.002) at 20 months. Baseline carriage in HIV uninfected children was 4.5%, and dropped to 2.3% after vaccination (p=0.3). HIV infected parents had 12.3 times increased risk of Hib carriage if their child was colonized (p=0.04) and 9.3 times increased risk if their child had persistent colonization post vaccine (p=0.05). No parent of HIV uninfected children had Hib colonization at any point. Pneumococcal colonization was associated with increased Hib colonization. CONCLUSION: Making the HibCV available to HIV infected children could interrupt Hib carriage in high risk families. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Barekar N.S.,Brunel University | Dhindaw B.K.,Indian Institute of Technology Kharagpur
Materials and Manufacturing Processes | Year: 2014

Since its invention by Sir Henry Bessemer in 1865, twin-roll casting (TRC) has been the subject of extensive research, not only to develop the technology but also to achieve an understanding of microstructural evolution. The present review confines itself to the literature on process aspect, modeling, and quality issues. Initially, the principles of the process are outlined. Modeling of fluid flow, heat transfer, and microstructural evolution, surface and internal defects in TRC of aluminum alloys are next discussed. The role of process parameters on solidification during casting is reviewed. The controls of grain structure by melt treatment are also discussed in brief. Copyright © 2014 Taylor & Francis Group, LLC.

Singh A.,Indian Institute of Technology Kharagpur
Agricultural Water Management | Year: 2012

Irrigated agriculture faces serious threats of waterlogging and soil salinisation in the arid and semi-arid regions of the world. To evaluate different options to solve the problem, the computer based simulation model, SaltMod was applied in a waterlogged area of Haryana State in India. After successful calibration (10 years) and validation (10 years), several alternative water management scenarios were studied for their long-term (15 years) impacts on groundwater levels and salinities. The alternative scenarios revealed that the groundwater levels would continue to rise in the long-run under the existing cropping patterns. Thus, suitable water management strategies such as reduction in rice area by 5-9%, reduction in canal water use by 7-10%, and increase in groundwater use by 6-8%, are suggested to bring the groundwater level down to a safe depth and to prevent further rising of the groundwater level. © 2012 Elsevier B.V.

Padmanabhan V.,Indian Institute of Technology Kharagpur
Journal of Chemical Physics | Year: 2013

Polymer nanocomposites have shown to exhibit improved mechanical properties compared to their pure host polymers. These property changes have been primarily attributed to the nature of polymer/nanoparticle interactions. Molecular dynamics simulations of model polymer nanocomposites have provided new insights into the molecular origin of property-changes in these nanocomposites. It was observed that addition of nanoparticles, induced adsorption of monomer segments onto the surface of nanoparticles creating high-density regions of polymer segments in the interfacial zones. A closer look into the morphology of these regions surrounding the nanoparticles revealed that mechanical reinforcement and changes in flow properties may be attributed to the formation of a percolated network of these high-density regions. © 2013 AIP Publishing LLC.

Singh A.,Indian Institute of Technology Kharagpur
Water Resources Management | Year: 2016

The formulation and application of two optimization models is presented in this study. The models were used to maximize the net farm revenue of an irrigated area located in northwest India by optimally allocating the available water and land resources. In order to moderate the rising water table issues, a ground water component was introduced in the model, while still ensuring optimal resources allocation. Results of the model indicates a reduction in barley, gram, mustard, and rice production area while at the same time an increase in sugarcane, millets, wheat, and cotton cultivation areas under optimal conditions. The ground water exploitation has increased in the model allocation, which consecutively moderated the rising water table problems. The model allocations has resulted in more than 31 % increase in net farm revenue. The proposed models can be employed as a dependable tool for making the decisions at local and regional levels and are capable of solving the rising water table issues of irrigated areas. The formulations proposed in this study are simple and can be employed anywhere for capitalizing on the farm revenue by moderating the water resources problems. The model constraints, though, be different considering the quality and quantity aspects of different water sources. © 2016 Springer Science+Business Media Dordrecht

Shaw A.,Indian Institute of Technology Kharagpur
Mechanics of Materials | Year: 2012

Penetration of rigid object into semi-infinite compressible solid is investigated in the present study. First a detailed numerical analysis of the penetration process is performed via smooth particle hydrodynamics. Based on the numerical results, estimate for the resistive force that the target exerts on the penetrating object is obtained. It is shown that in the computation of the resistive force the quasi-static coefficient can accurately be obtained through the spherical cavity expansion theory. However for a given target material the coefficient associated with the hydro-dynamic term significantly depends on the impact velocity unlike commonly assumed constant values. Penetration equations for rigid object with arbitrary nose geometries are derived. Developed analytical model is then verified through some experimental and analytical results reported in the literature. © 2012 Elsevier Ltd. All rights reserved.

Kumar S.,Indian Institute of Technology Kharagpur
Archives of Civil and Mechanical Engineering | Year: 2016

An ultrasonic vibration setup has been designed and fabricated to make a comparative study between conventional frictions stir processing and ultrasonic assisted friction stir processing. Effects of ultrasonic vibrations on rotational speeds as well as processing speeds are studied. A series of experiments are performed to determine effect of ultrasonic vibrations. From the experimental results, it is seen that ultrasonic vibrations help in generating high heat in the stirred zone of friction stir processing which causes intense plastic deformation and improves material flow. By using the ultrasonic vibrations, higher hardness and tensile strength of friction stir processed joints are evident. Further axial force and transverse force reduction is also visible in case of ultrasonic assisted friction stir processing. © 2016 Politechnika Wrocławska.

Sharma S.P.,Indian Institute of Technology Kharagpur
Computers and Geosciences | Year: 2012

Employing the very fast simulated annealing (VFSA) global optimization technique, a FORTRAN program is developed for the interpretation of one-dimensional direct current resistivity sounding data from various electrode arrays. The VFSA optimization depicts various good fitting solutions (models) after analyzing a large number of models within a predefined model space. Various models that yield reasonably well fitting responses with the observed response lie along a narrow elongated region of the model space. Therefore, instead of selecting the global model on the basis of the lowest misfit error, it is better to analyze histograms and probability density functions (PDFs) of such models for depicting the global model. In a multidimensional model space, the most appropriate region to select suitable models to compute the mean model is the one in which the PDF is larger in comparison to the other regions of the model space. Initially, accepted models with misfit errors less than the predefined threshold value are selected and lognormal PDFs for each model parameter are computed. Subsequently, mean model and uncertainties are computed using the models in which each model parameter has a PDF more than the defined threshold value (>68.2%). The mean model computed from such models is very close to the actual subsurface structure (global model). It is observed that the mean model computed using models with a PDF more than 95% for each model parameters yields the actual model. Moreover uncertainty computed using models with such a high PDF and lying in a small model space will be small and it will not be considered as the actual global uncertainty. Resistivity sounding (synthetic and field) data over different subsurface structures are optimized using the VFSA program developed in the present study. Optimization results reveal that the actual model always locates within the estimated uncertainty in the mean model. Since the approach requires much less computing time (a few minutes) using an ordinary PC, results with smaller uncertainty can be obtained using repeated computations with a smaller search range in comparison to the results obtained in a large search range. The efficacy of the program is demonstrated by interpreting data from various layered earth structures. Field examples associated with groundwater and mineral exploration are also presented. Interpreted model parameters show excellent correlation with drilling results. The optimization program can be used for various case studies like those associated with groundwater, mineral exploration, subsurface pollution studies, and saline water incursion in coastal areas. © 2011 Elsevier Ltd.

Jana A.K.,Indian Institute of Technology Kharagpur
Applied Energy | Year: 2016

This work introduces a new heat integrated distillation column (HIDiC) for batch processing. Under this scheme, the entire cylindrical shell is proposed to divide vertically by a metal wall into two closed semi-cylinders. Aiming to generate an internal heat source, a heat pump system is employed over the left hand division to elevate the pressure of the right hand part with the application of HIDiC concept. This new divided-wall HIDiC column utilizes its own energy source by transferring heat from the high pressure (HP) to low pressure (LP) side, thereby reducing the utility consumption in both the still and condenser. To make this thermal integration technology more effective, a typical tray configuration is proposed in both sides of the divided-wall. Unlike the continuous flow distillation, the batch column shows unsteady state process characteristics that make its operation more challenging. With this, an open-loop variable manipulation policy is formulated so that the dynamics of the heat integrated column remain close, if not same, with its conventional counterpart. This is a necessary condition required for a fair comparison between them. Finally, the proposed configuration is illustrated by a binary column, showing an improvement in energy savings, entropy generation and cost over its conventional analogous. This thermally integrated configuration is relatively simple than the traditional HIDiC in terms of design and operation. © 2016 Elsevier Ltd.

Mandal S.K.,Indian National Institute of Foundry and Forge Technology | Chan F.T.S.,Hong Kong Polytechnic University | Tiwari M.K.,Indian Institute of Technology Kharagpur
Expert Systems with Applications | Year: 2012

The generation of leak along the pipeline carrying crude oils and liquid fuels results enormous financial loss to the industry and also affects the public health. Hence, the leak detection and localization problem has always been a major concern for the companies. In spite of the various techniques developed, accuracy and time involved in the prediction is still a matter of concern. In this paper, a novel leak detection scheme based on rough set theory and support vector machine (SVM) is proposed to overcome the problem of false leak detection. In this approach, 'rough set theory' is explored to reduce the length of experimental data as well as generate rules. It is embedded to enhance the decision making process. Further, SVM classifier is employed to inspect the cases that could not be detected by applied rules. For the computational training of SVM, this paper uses swarm intelligence technique: artificial bee colony (ABC) algorithm, which imitates intelligent food searching behavior of honey bees. The results of proposed leak detection scheme with ABC are compared with those obtained by using particle swarm optimization (PSO) and one of its variants, so-called enhanced particle swarm optimization (EPSO). The experimental results advocate the use of propounded method for detecting leaks with maximum accuracy. © 2011 Elsevier Ltd. All rights reserved.

Roy S.S.,National Institute of Technology Durgapur | Pratihar D.K.,Indian Institute of Technology Kharagpur
Expert Systems with Applications | Year: 2012

Turning gaits are the most general and very important ones for omni-directional walking of a six-legged robot. Soft computing-based expert systems have been developed in the present work to predict specific energy consumption and stability margin of turning gait of a six-legged robot. Besides back-propagation neural network, three approaches based on adaptive neuro-fuzzy inference system have been developed and their performances are compared with each other. Genetic algorithm-tuned multiple adaptive neuro-fuzzy inference systems are found to perform better than other approaches. This could be due to a more exhaustive search conducted by the genetic algorithm in place of back-propagation algorithm and the use of two separate adaptive neuro-fuzzy inference systems for two different outputs. © 2011 Elsevier Ltd. All rights reserved.

Ramlugun G.S.,Manipal University India | Nagarajan V.K.,Manipal University India | Chakraborty C.,Indian Institute of Technology Kharagpur
Expert Systems with Applications | Year: 2012

This paper introduces a systematic approach for segmentation of retinal blood vessels towards the diagnosis of proliferative diabetic retinopathy (PDR) from digital fundus images. Here, 2D-Match (Gabor) filters are used on digital fundus images in which the vessels are enhanced by contrast-limited adaptive histogram equalization (CLAHE). A double sided thresholding scheme is then used to segment the vessels. Hysteresis thresholding is performed with the large and small vessels clipped at different intensity levels in order to reconstruct the vessels in the image. This vessel extraction technique leads to high accuracy (93.1%) in comparison with the ground truth images provided in the DRIVE database. © 2011 Elsevier Ltd. All rights reserved.

Dey K.,Indian Institute of Technology Kharagpur | Murthy V.M.S.R.,Indian School of Mines
Tunnelling and Underground Space Technology | Year: 2012

Drilling and blasting is the predominant rock excavation technique in driving horizontal tunnels. This often results in large overbreak. One of the prime reasons for overbreak is the unacceptable levels of ground vibration generated in blasting. From the literature survey and practical experience, it was found that threshold levels of PPV for overbreak depends on rock properties, namely, rock strengths, P-wave velocity, specific gravity, Poisson's ratio and rockmass parameters. Determination of threshold level of peak particle velocity (PPV) is crucial for controlling blast-induced overbreak and can be approximated by extrapolating the vibration predictor established from near-field vibration monitoring. This paper reports the experiments carried out in five horizontal tunnels for monitoring near-field ground vibration using accelerometer-based-seismograph planted in roof/sidewalls to establish ground vibration predictors. Blast-induced overbreak for each blast has been measured using a telescopic profiler. The threshold levels of PPV for overbreak have been estimated from the extrapolated vibration predictors to the overbreak zone and also using near field approximation technique. The estimated threshold levels of PPV for overbreak ranged between 590 and 1050. mm/s in extrapolation model and 410-890. mm/s in near-field HP model. Apart from these, a relationship between the percentage overbreak and rock/rockmass, charge and blast design parameters has been established through multivariate regression analysis of the data pertaining to five investigating sites. The result has been validated for four blasts within reasonable accuracy. © 2011 Elsevier Ltd.

The Eastern Ghats Province underwent major orogenic events in the Neoproterozoic-Cambrian period: 980-930, 900-650 and 550-500Ma. At each time interval, deformation occurred synchronous with high-grade metamorphism. The first event was characterized by distributed strain throughout the entire province, while strain and thermal anomalies during the later orogenies were confined to the province boundaries. In the first case, pre-orogenic rifting caused ultrahigh-temperature metamorphism at the base of the crust, and was closely followed by crustal shortening related to the collision of the granulite belt with the Indian craton. The thermal anomaly persisting from the rifting event, followed by the thermal relaxation associated with crustal shortening led to prolific melt production and transfer of heat producing elements (HPE) into the middle and upper parts of the thick post-collisional crust. Heating and associated melting caused rheological weakening of the crustal section, and explains why strain was distributed across the entire thermally perturbed zone. Erosion removed a substantial portion of the HPE-rich upper crust, and deposited the detritus in cratonic sedimentary basins to the west. Subsequently, the rheologically stronger Eastern Ghats Province crust could effectively transmit stresses and concentrate them along pre-existing zones of weakness near the province boundaries. Progressive thrusting in these domains led to consistent loading of the footwall, even as it underwent thermal relaxation. Since both strain and heating were associated with the footwall of pre-existing discontinuities, the 'hot orogen' so formed was also spatially restricted. © 2011 John Wiley & Sons, Ltd..

Singh A.,Indian Institute of Technology Kharagpur
Journal of Hydrology | Year: 2010

The long-term success of irrigated agriculture for sustainable crop production in India depends largely on the careful management of land and water resources. Currently, some serious environmental problems of waterlogging and soil salinization are burgeoning in parts of Haryana State of India; half a million hectare area of the State is already waterlogged. Poor irrigation and drainage management and inadequate exploitation of saline ground water are the main factors responsible for this phenomenon. In order to prevent further degradation and to maintain the food production for the growing population, judicious use of natural resources is a must. A wide range of solutions could be considered to address the problems. But the effectiveness of all the solutions and their combinations cannot be verified with on-farm experiments. Simulation models by way of their predictive capability are often the only viable means of providing input to management decisions. These models can help to forecast the likely impacts of a particular alternative management strategy. In the present study a physical based one-dimensional simulation model SWASALT was employed to evaluate on-farm irrigation water management options. After successful calibration and validation with field experimentation data, several scenario building exercises have been conducted under different crop, soil and rainfall conditions. The water and salt balance component obtained for each simulation run were used to derive water management response indicators. The simulation study revealed that in most conditions, saline water of up to 7.5. dS/m can be used safely on long term basis for crop production. The simulation study further revealed that alternative use of canal and saline water had an edge over mix use. Several alternatives have been suggested for sustainable agricultural production in the region. The strategies suggested, if followed, would lend sustainability to the agricultural production besides substantial increase in production and water resources conservation, by impeding the environmental hazard of waterlogging and soil salinization. © 2010 Elsevier B.V.

Nagesh D.S.,Delhi Technological University | Datta G.L.,Indian Institute of Technology Kharagpur
Applied Soft Computing Journal | Year: 2010

This paper explains an integrated method with a new approach using experimental design matrix of experimental designs technique on the experimental data available from conventional experimentation, application of neural network for predicting the weld bead geometric descriptors and use of genetic algorithm for optimization of process parameters. The properties of the welded joints are affected by a large number of welding parameters. Modeling of weld bead shape is important for predicting the quality of welds. In an attempt to model the welding process for predicting the bead shape parameters (also known as bead geometry parameters) of welded joints, modeling and optimization of bead shape parameters in tungsten inert gas (TIG) welding process has been tried in the present work. Multiple linear regression technique has been used to develop mathematical models for weld bead shape parameters of TIG welding process, considering the effects of main variables as well as two factor interactions. Also by using the same experimental data, an attempt has been made to predict the bead shape parameters using back-propagation neural network. To optimize the process parameters for the desired front height to front width ratio and back height to back width ratio, genetic algorithmic approach has been applied. © 2009 Elsevier B.V. All rights reserved.

Misra R.,Indian Institute of Technology Patna | Mandal C.,Indian Institute of Technology Kharagpur
IEEE Transactions on Parallel and Distributed Systems | Year: 2010

A minimum connected dominating set (MCDS) is used as virtual backbone for efficient routing and broadcasting in ad hoc sensor networks. The minimum CDS problem is NP-complete even in unit disk graphs. Many heuristics-based distributed approximation algorithms for MCDS problems are reported and the best known performance ratio has (4.8+ln 5). We propose a new heuristic called collaborative cover using two principles: 1) domatic number of a connected graph is at least two and 2) optimal substructure defined as subset of independent dominator preferably with a common connector. We obtain a partial Steiner tree during the construction of the independent set (dominators). A final postprocessing step identifies the Steiner nodes in the formation of Steiner tree for the independent set of G. We show that our collaborative cover heuristics are better than degree-based heuristics in identifying independent set and Steiner tree. While our distributed approximation CDS algorithm achieves the performance ratio of (4.8+ln 5)opt + 1.2, where opt is the size of any optimal CDS, we also show that the collaborative cover heuristic is able to give a marginally better bound when the distribution of sensor nodes is uniform permitting identification of the optimal substructures. We show that the message complexity of our algorithm is O(nΔ2), Δ being the maximum degree of a node in graph and the time complexity is O(n). © 2010 IEEE.

Chattopadhyay S.,Heritage Institute of Technology | Sen R.,Indian Institute of Technology Kharagpur
Bioresource Technology | Year: 2013

A novel integrated immobilized enzyme-reactor system involving a continuous stirred tank reactor with two packed bed reactors in series was developed for the continuous production of biodiesel. The problem of methanol solubility into oil was solved by introducing a stirred tank reactor to dissolve methanol into partially converted oil. This step made the process perfectly continuous without requiring any organic solvent and intermittent methanol addition in the process. The substrate feeding rate of 0.74. mL/min and enzyme loading of 0.75. g per reactor were determined to be optimum for maximum biodiesel yield. The integrated continuous process was stable up to 45 cycles with biodiesel productivity of 137.2. g/L/h, which was approximately 5 times higher than solvent free batch process. In comparison with the processes reported in literature using expensive Novozyme 435 and hazardous organic solvent, the present process is completely green and perfectly continuous with economic and environmental advantages. © 2013 Elsevier Ltd.

Maity R.,Indian Institute of Technology Kharagpur | Ramadas M.,Purdue University | Govindaraju R.S.,Purdue University
Water Resources Research | Year: 2013

Drought triggers are patterns in hydroclimatic variables that herald upcoming droughts and form the basis for mitigation plans. This study develops a new method for identification of triggers for hydrologic droughts by examining the association between the various hydroclimatic variables and streamflows. Since numerous variables influence streamflows to varying degrees, principal component analysis (PCA) is utilized for dimensionality reduction in predictor hydroclimatic variables. The joint dependence between the first two principal components, that explain over 98% of the variability in the predictor set, and streamflows is computed by a scale-free measure of association using asymmetric Archimedean copulas over two study watersheds in Indiana, USA, with unregulated streamflows. The M6 copula model is found to be suitable for the data and is utilized to find expected values and ranges of predictor hydroclimatic variables for different streamflow quantiles. This information is utilized to develop drought triggers for 1 month lead time over the study areas. For the two study watersheds, soil moisture, precipitation, and runoff are found to provide the fidelity to resolve amongst different drought classes. Combining the strengths of PCA for dimensionality reduction and copulas for building joint dependence allows the development of hydrologic drought triggers in an efficient manner. ©2013. American Geophysical Union. All Rights Reserved.

Das T.,Max Planck Institute for Intelligent Systems (Stuttgart) | Chakraborty S.,Indian Institute of Technology Kharagpur
Biomicrofluidics | Year: 2013

According to the World Health Organization, cancer is one of the leading causes of death worldwide. Cancer research, in its all facets, is truly interdisciplinary in nature, cutting across the fields of fundamental and applied sciences, as well as biomedical engineering. In recent years, microfluidics has been applied successfully in cancer research. There remain, however, many elusive features of this disease, where microfluidic systems could throw new lights. In addition, some inherent features of microfluidic systems remain unexploited in cancer research. In this article, we first briefly review the advancement of microfluidics in cancer biology. We then describe the biophysical aspects of cancer and outline how microfluidic system could be useful in developing a deeper understanding on the underlying mechanisms. We next illustrate the effects of the confined environment of microchannel on cellular dynamics and argue that the tissue microconfinement could be a crucial facet in tumor development. Lastly, we attempt to highlight some of the most important problems in cancer biology, to inspire next level of microfluidic applications in cancer research. © 2013 American Institute of Physics.

Irrigation is essential for achieving food security to the burgeoning global population but unplanned and injudicious expansion of irrigated areas causes waterlogging and salinization problems. Under this backdrop, groundwater resources management is a critical issue for fulfilling the increasing water demand for agricultural, industrial, and domestic uses. Various simulation and optimization approaches were used to solve the groundwater management problems. This paper presents a review of the individual and combined applications of simulation and optimization modeling for the management of groundwater-resource problems associated with irrigated agriculture. The study revealed that the combined use of simulation-optimization modeling is very suitable for achieving an optimal solution for groundwater-resource problems, even with a large number of variables. Independent model tools were used to solve the problems of uncertainty analysis and parameter estimation in groundwater modelling studies. Artificial neural networks were used to minimize the problem of computational complexity. The incorporation of socioeconomic aspects into the groundwater management modeling would be an important development in future studies. © 2015, Springer-Verlag Berlin Heidelberg.

Bassani J.L.,University of Pennsylvania | Racherla V.,Indian Institute of Technology Kharagpur
Progress in Materials Science | Year: 2011

In non-close-packed crystalline lattices, e.g. of bcc metals and intermetallic compounds, the stress-state dependence of the Peierls barrier for the motion of a screw dislocation violates Schmid's law and leads to non-associated plastic flow at the continuum level. Plasticity models based upon distinct yield and flow functions are developed for both single crystals and polycrystalline aggregates that build upon atomic-level simulations of single dislocations. For a random polycrystal, isotropic forms for those functions are proposed and used to study mechanisms of macroscopic deformation. Non-associated flow is shown to have a significant effect on strain localization. Intermittent strain bursts are predicted to arise as a consequence of non-associated flow, particularly for deformations close to the plane strain state and for nearly rate-insensitive response. © 2011 Elsevier Ltd. All rights reserved.

Maity A.K.,Indian Institute of Technology Kharagpur | Roy S.,Indian Institute of Technology Bhubaneswar
Journal of Organic Chemistry | Year: 2012

A multimetallic piano-stool complex [Cp*Ir(SnCl 3) 2{SnCl 2(H 2O) 2}] (1) having Ir-Sn 3 motif has been synthesized from [Cp*IrCl 2] 2 and SnCl 2. The multimetallic complex catalytically promotes the nucleophilic substitution reaction (here after α-amidoalkylation reaction) of γ-hydroxylactams generated from phthalimidals to obtain decorated isoindolinones in excellent yields. Succinamidals, however, lead to the substituted pyrrolidinones (thermodynamic control product) via S N1-type path as well as eliminated pyrrolinones (kinetic control product) via an E1-type path, depending on the reaction parameters. A straightforward application of this methodology is to synthesize benzo-fused indolizidine alkaloid mimics. © 2012 American Chemical Society.

Accurate estimation of the groundwater recharge is essential for efficient and sustainable groundwater management in arid and semi-arid regions, as water resources are critical to economic development in these areas. Various techniques are available to quantify recharge. The hydrological budget model proposed herein is unique, simple, and easy to apply. It uses data on groundwater level, groundwater extraction, and distributed specific yield information for estimating groundwater recharge. The Model is employed to estimate the seasonal long-term (35. years, e.g., from 1974 to 2009) groundwater recharge of an irrigated semi-arid area located in Haryana State of India, where groundwater levels are rising, continuously. The results are analysed to provide an overview of the process dynamics that led to imbalance of the system. Groundwater recharge analysis during the study period reveals that percolation from irrigated fields is the main recharge component with 49% contribution to the total recharge. An annual groundwater table rise of 0.14. m has been estimated for the study area. Various potential solution alternatives are evaluated to mitigate the problems of waterlogging and salinisation, considering the socio-economic issues which have wider policy significance on sustainability. Several suitable water management strategies such as reduction in rice area, increase in pumping volume and using the groundwater conjunctively with higher quality canal water, and lining of canal networks are suggested to bring the watertable down to a safe limit and to prevent further rising of the watertable. Among the potential solution alternatives studied, the one which considers 10% reduction in rice area along with 2% increase in pumping volume and 20% canal lining, yields best result for mitigating the waterlogging problems. © 2011 Elsevier B.V.

Mehta C.R.,Central Institute of Agricultural Engineering | Tewari V.K.,Indian Institute of Technology Kharagpur
International Journal of Industrial Ergonomics | Year: 2015

A biomechanical model is important for prediction of loads likely to arise in specific body parts under various conditions. The biomechanical model was developed to predict compressive and shear loads at L4/L5 (lumbar vertebra) of a tractor operator seating on seats with selected seat pan and backrest cushion materials. A computer program was written to solve the model for various inputs viz. stature and weight of the tractor operators, choice of operating conditions, and reaction forces from seat pan and backrest cushions. It was observed that maximum compressive and shear forces ranged 943-1367N and 422-991N, respectively at L4/L5 of tractor operators steering the tractor with leg and hand control actions and occasionally viewing the implement at back. The compressive forces were maximum (1202-1367N) with coir based composite seat backrest cushion materials (thickness of 80mm, density of 47.19kg/m3) and were minimum (943-1108N) with high density polyurethane foam (thickness of 44mm, density of 19.09kg/m3) for the seats. Relevance to industry: The biomechanical model of a tractor operator is important for theoretical understanding the problem of sitting and is also valuable in prediction of compressive and shear loads at L4/L5 of operator under various operating conditions. It will help in design of tractor seat for operator's comfort. © 2015 Elsevier B.V.

Sinha S.K.,Indian Institute of Technology Kharagpur
Sensors and Actuators, B: Chemical | Year: 2015

Randomly oriented Sn-doped ZnO (Zn1-xSnxO) nanofibers have been synthesized by a facile evaporation and re-condensation technique using metallic Sn and Zn as precursors in Ar-2% O2 atmosphere at 850°C on Si substrates. The dimension of the Zn1-xSnxO nanofibers ranges from 100 nm to 200 nm in diameters and lengths up to few mm. The XRD patterns reveal a set of distinct diffraction peaks indexed as the wurtzite hexagonal ZnO phase. The growth mechanism is dominated by a catalyst-free vapor solid process and the preferred growth direction of Sn-doped ZnO nanofibers is along the [0 0 0 1] direction. The NH3 sensing properties of the as-deposited nanostructures are investigated for different vapor concentrations (10, 25, 50, 100 and 200 ppm) and working temperatures (200, 250, 300, 350°C). Zn1-xSnxO nanofibers are found to possess better sensitivity toward the ammonia vapor as compared to pristine or undoped ZnO nanowires at identical experimental conditions. The gas sensing mechanism of the nanostructures has been discussed in detail. The high sensitivity and dynamic reproducibility of these sensor materials reveal that this composition and morphology can be applied to fabricate sensing devices for detecting ammonia vapor at low to medium concentration range. © 2015 Elsevier B.V. All rights reserved.

Maiti J.,Indian Institute of Technology Kharagpur
Safety Science | Year: 2010

This study proposes a new way of analyzing and evaluating worksystem safety based on probability models, control charts, loss functions and safety capability index. The step-by-step procedures for development of worksystem safety capability index (WSCI) are presented. The development starts with the adoption of process approach to model safety. The key feature of this development is the effective assimilation of quality engineering concepts into safety study. A case study was done in an underground coal mining situation to operationalize the development. Time between occurrences (TBO) of injuries and number of injuries (NOI) per month are considered as safety performance variables. The application shows encouraging results for safety improvement through adoption of control charts, expected loss and WSCI. The development opportunity, application potential and future scope of research are discussed. © 2010 Elsevier Ltd.

Chinnasamy S.S.,University of KwaZulu - Natal | Mishra B.,Indian Institute of Technology Kharagpur
Economic Geology | Year: 2013

Gold mineralization at Jonnagiri is hosted in laminated quartz veins within sheared granodiorite in a typical Archean greenstone-granitoid ensemble. The greenstones and the intrusive granodiorite have been affected by two folding and shearing events, respectively. THERMOCALC-aided P-T calculations suggested that lower amphibolite-grade metamorphism affected the greenstones, involving peak conditions at ~5 kbar and 500°C. Gold mineralization is characterized by a chlorite + biotite-rich proximal alteration zone and a muscovitedominant inner zone among laminated auriferous quartz veins. Whereas the proximal zone had significant gain in S, C, K, Si, and Rb and depletion of Ca, Mg, and Fe, the inner alteration zone is typified by major addition of Si, K, S, C, and Au. General depletion of rare earth elements in the altered granodiorites is ascribed to high ambient fluid/rock during hydrothermal alteration. Results of the computed (aMg 2+/aH +2) vs. (aK +/aH +) and (aNa +/aH +) vs. (aK +/a H +) diagrams, along with an increase in carbonation and alkali enrichment indices in the altered rocks, explain the observed hydrothermal alteration-induced mineralogical changes and constrain the possible fluid composition. Gold occurs as fracture fillings in the quartz matrix and pyrite grains, together with other sulfides, and associated with the f S2-buffering assemblage pyrite + pyrrhotite. Arsenopyrite compositions in the pyrite-arsenopyrite assemblage yielded temperature and log fS2 ranges of 305° to 335°C and -10.9 to -8.6, respectively. These temperature estimates compare well with the published results of chlorite thermometry (263°-323°C). Mineral-fluid equilibrium computations place narrow constraints on the ore fluid fO2 (and aH2S). Gold precipitation was a consequence of postpeak metamorphic fluid phase separation involving immiscibility of gaseous spies, fluid-rock interaction, and decrease in fO2 of the fluid. Published δ34S values in pyrite fall in a narrow range of 1.4 to 7.1‰, and the calculated δ34S H2S varies from 0.2 to 5.8‰, at log f O2 = -32.6 and pH = 5.15 to 5.95; these imply that Au(HS)2 - was the dominant gold complex. The narrow range of δ34SPy values is indicative of magmatic (± mantle) source, or involvement of fluid with an average crustal sulfur composition. The geologic events responsible for Jonnagiri started with accretion of the greenstone package at the subduction boundary between the eastern and western blocks of the Dharwar craton, followed by their deformation, shearing, and metamorphism, with subsequent emplacement of the Pagadarayi granodiorite and continued shearing, culminating with fluid flow focused along the shear fractures, which resulted in postpeak metamorphic hydrothermal alteration and precipitation of gold-bearing quartz lodes. From the observed craton-scale uniformity in the chemical and sulfur isotope compositions of the ore fluids, we propose a model involving contamination of an auriferous metamorphic fluid with crustal sulfur during its upward transport. ©2013 Society of Economic Geologists, Inc.

Chemical U-Th-total Pb dating method is a low-cost and reliable technique to estimate the age of monazites of detrital and diagenetic origin or those found in low to high-T metamorphic or magmatic rocks using electron microprobe (EMP) analyses. The method has been commonly applied for age estimation in Phanerozoic and Proterozoic rocks and less commonly in Neoarchean rocks. Monazite dates from the Paleoarchean era are rare and the associated error % of spot age (=. [2σ error/absolute age]. ×. 100) is high, i.e., between 2 and 26%. The errors associated with chemical dating of monazite are significantly larger compared to isotope methods, which impede precise age estimation and age resolution in polygenetic monazites of Neoarchean and older rocks.In this study, simultaneous element analyses in multiple spectrometers and the sub-counting method of analyses are employed to obtain precise estimates of U, Th and Pb concentrations in monazite. Using vanadinite [Pb5(VO4)3Cl] as the Pb standard (instead of PbS), the method yields an age of 3118+/-28Ma with Mount Narryer Mesoarchean monazite (Thermal Ionization Mass Spectrometry [TIMS] age: 3132+/-1Ma) and 516+/-12Ma with Moacyr monazite (TIMS age: 509+/-1Ma; EMP monazite age: 497+/-10Ma) as the reference samples. The modifications led to ~40% reduction in spot age errors in the Mount Narryer sample relative to those obtained by conventional monazite dating method. The reduced errors in spot ages helped in resolving statistically un-mixed age populations (3152+/-16Ma, 3322+/-15Ma and 3420+/-140Ma) in polygenetic monazites within muscovite-quartz schists from the Singhbhum Craton, Eastern India. The significance of these dates is briefly discussed. © 2013 Elsevier B.V.

Deck O.,University of Lorraine | Singh A.,Indian Institute of Technology Kharagpur
International Journal for Numerical and Analytical Methods in Geomechanics | Year: 2012

The objective of this study is to develop an analytical model that can predict the building-relevant deflections induced by tunnelling or mining subsidence. The model takes into account soil-structure interactions due to differences in stiffness between the ground and the building. The ground is modelled by the Winkler model with an initial ground curvature equivalent to the free-field ground movements. The building is modelled by a horizontal beam with uniform loading. The static and cinematic equilibrium of both the ground and the building are then calculated to assess the final building and ground shape, and the building deflection is derived. The resulting analytical model is used to investigate the influence of the ground and the building's mechanical properties, the building load and the initial value of the free-field ground curvature (hogging or sagging). The model appears to be more comprehensive than those reported elsewhere that address the problem with numerical models. In particular, the analytical model makes it possible to distinguish two different final situations-with continuous or discontinuous contact between the ground and the building. The model is compared with numerical results and used to analyse a case study. © 2010 John Wiley & Sons, Ltd.

Dash S.K.,Indian Institute of Technology Kharagpur | Bora M.C.,Indian Institute of Technology Guwahati
Geotextiles and Geomembranes | Year: 2013

A series of experiments have been carried out to develop an understanding of the performance improvement of soft clay foundation beds using stone column-geocell sand mattress as reinforcement. It is found that with the provision of stone columns, of adequate length and spacing, about three fold increases in bearing capacity can be achieved. While with geocell-sand mattress it is about seven times that of the unreinforced clay. But if combined together, the stone column-geocell mattress composite reinforcement, can improve the bearing capacity of soft clay bed as high as by ten fold. The optimum length and spacing of stone columns giving maximum performance improvement are, respectively, 5 times and 2.5 times of their diameter. The critical height of geocell mattress can be taken equal to the diameter of the footing, beyond which, further increase in bearing capacity of the composite foundation bed is marginal. © 2013 Elsevier Ltd.

Pala P.,Motilal Nehru National Institute of Technology | Bhattacharyya S.K.,Indian Institute of Technology Kharagpur
Journal of Fluids and Structures | Year: 2013

This paper deals with the studies of sloshing of liquid in partially filled rectangular composite containers subjected to external excitation. The governing equation for inviscid fluid is written as pressure variable form. At each time step, the pressure is evaluated using the meshless local Petrov-Galerkin (MLPG) approach. A local symmetric weak form (LSWF) for linearized sloshing is developed, and a truly meshless method, based on LSWF and moving least squares (MLS) approximation, is presented for the solution of Laplace equation with the requisite boundary conditions. The effectiveness of the developed algorithm is demonstrated through few numerical examples. The comparison of results in terms of natural slosh frequencies, sloshing amplitudes and hydrodynamic pressures obtained in the present investigation are made with those available in the reported literature. To observe the change in the total liquid response due fluid-structure interaction effects, parametric studies are carried out for different cases by varying the fibre orientations and wall thicknesses in the laminated container wall. The present meshless method based on LSWF is found to be simple and attractive with a great potential in engineering applications. © 2013 Elsevier Ltd.

Jana A.K.,Indian Institute of Technology Kharagpur
IEEE Transactions on Industrial Informatics | Year: 2013

In this contribution, an extended generic model control (EGMC) law is proposed based on differential geometry theory. This multivariable nonlinear control system requires the knowledge of the internal state of the process. To cope with this, an adaptive control scheme is formulated here. This adaptive nonlinear control law combines the EGMC with the Luenberger-type nonlinear state estimator (LNSE). Deriving the control law and the state estimator, the stability properties of the EGMC, LNSE and the combined EGMC-LNSE structure are developed. The application and performance of the proposed adaptive EGMC-LNSE control law are finally illustrated by a simulated industrial refinery process (i.e., debutanizer). The representative column has 169 state variables, and it was operated in the province of Alberta, Canada. It is surprising to note that the LNSE scheme aims to estimate a few states that are solely required for the controller based on only two component balance equations. As a consequence, there exists a significant structural discrepancy and despite it, the proposed nonlinear controller shows its superiority over the multivariable dynamic matrix controller. © 2005-2012 IEEE.

Ghosh S.,Defence Research and Development Organisation | Mukhopadhyay S.,Indian Institute of Technology Kharagpur
IEEE Transactions on Aerospace and Electronic Systems | Year: 2011

In this paper an acceleration model and a jerk model are proposed for estimation of the kinematic state of reentry ballistic targets (RBTs) using extended Kalman filters (EKF). The models proposed here use the equations of target kinematics only and do not assume any model parameterization for variation of the ballistic coefficient and air density a priori, as found in the literature. The novelty lies in estimation of the ratio (γ) of air density and ballistic coefficient and its time derivatives using a separate Kalman filter (KF) (γ-filter) which utilizes pseudo measurements of γ computed from the velocity and acceleration estimated by the EKF at each time step. The parameter γ and its derivatives estimated by the γ-filter are, in turn, used for the estimation of position, velocity, acceleration, and jerk in the EKF. The use of the pseudo measurements of γ makes the algorithms inherently adaptive to variations of the ballistic coefficient and air density during reentry. A comparative assessment of several dynamic models for reentry of ballistic targets reported in the literature and those proposed here demonstrates that the estimation errors in velocity and acceleration are significantly less for the proposed models compared with the existing ones. © 2011 IEEE.

Anis A.,Indian Institute of Technology Kharagpur | Lvovsky A.I.,University of Calgary | Lvovsky A.I.,Russian Quantum Center
New Journal of Physics | Year: 2012

Coherent-state quantum process tomography (csQPT) is a method for completely characterizing a quantum-optical 'black box' by probing it with coherent states and carrying out homodyne measurements on the output (Lobino et al 2008 Science 322 563). We present a technique for csQPT that is fully based on statistical inference, in particular, quantum expectation-maximization. The method relies on the Jamiolkowski isomorphism and iteratively reconstructs the process tensor in the Fock basis directly from the experimental data. This approach permits incorporation of a priori constraints into the reconstruction procedure, thereby guaranteeing that the resulting process tensor is physically consistent. Furthermore, our method is easier to implement and requires a narrower range of coherent states than its predecessors. We test its feasibility using simulations on several experimentally relevant processes. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Ghosh Ray S.,Advanced Technology Development Center | Ghangrekar M.M.,Indian Institute of Technology Kharagpur
Bioresource Technology | Year: 2015

For enhancing organic matter removal from cereal-based distillery stillage two-stage treatment consisting of fermentation by Aspergillus awamori followed by microbial fuel cell (MFC) is proposed. Considerable reduction in total and soluble chemical oxygen demand (COD) up to 70% and 40%, respectively, along with 98% reduction of suspended solids (SS) has been achieved during fungal pretreatment. The process generated chitosan, a useful fermentation byproduct from fungal mycelia, as 0.6-0.7g/l of settled sludge with mycelium (3.8% solids). Prior treatment of wastewater with fungal strain enhanced the power generation in MFC by 2.9 times at an organic loading rate of 1.5kgCOD/m3day, demonstrating soluble COD reduction of 92% in MFC. While treating distillery wastewater, this two-stage integrated biological process demonstrated overall 99% COD removal and almost complete removal of SS, delivering ample scope for scale-up and industrial application to offer effective solution for distillery wastewater treatment. © 2014 Elsevier Ltd.

Berry M.V.,H H Wills Physics Laboratory | Shukla P.,Indian Institute of Technology Kharagpur
Journal of Physics A: Mathematical and Theoretical | Year: 2012

The association between large shifts of a pointer in a weak measurement and fast oscillations in an associated function involving the pre- and post-selected states has been clarified in a recent paper (Aharonov et al 2011 J. Phys. A: Math. Theor. http://dx.doi.org/10.1088/1751-8113/44/36/365304). Here we explore the association further for the case of an observable with N discrete eigenvalues, by calculating and illustrating how the supershift emerges, even for N = 2, as the uncertainty in the pointer position increases. This happens if the initial pointer wavefunction is Gaussian or Lorentzian but not if it is exponential.

Sarkar J.,Indian Institute of Technology BHU Varanasi | Bhattacharyya S.,Indian Institute of Technology Kharagpur
Energy | Year: 2015

India has great potential to employ the ORC (organic Rankine cycle) technology for conversion of low temperature waste heat and renewable energy. In this study, available waste heat and relevant renewable heat sources in India are reviewed and suitable working fluids for ORC have been selected based on operational, environmental and safety criteria. A feasibility study and comparison of selected fluids for ORC is also presented for Indian climates along with discussions on component, operation and cost related aspects. A comprehensive review on available heat sources and sinks shows that India has plenty of waste heat and renewable energy sources for electricity generation by means of ORC; however, condenser operation may be challenging due to wide ambient temperature variation. Appropriate performance comparison among selected working fluids shows that ammonia is the best fluid in terms of net power generation and compactness of turbo-machineries, whereas n-Pentane is the best fluid in terms of thermal efficiency and heat exchanger compactness. Both are recommended as working fluids for ORC installations in India. The study reveals that there is a great opportunity to employ this technology in India provided we have to overcome some challenges related to component selection, finance and maintenance. © 2015 Elsevier Ltd.

Sen R.,Indian Institute of Technology Kharagpur
Advances in Experimental Medicine and Biology | Year: 2010

Even after forty years of its discovery by Arima et al7, surfactin, a potent lipopeptide biosurfactant, still attracts attention and fancy of the applied microbiologists and biotechnologists worldwide, mainly due to its versatile bioactive properties and potential industrial implications. Starting from its first invented characteristic as an inhibitor of fibrin clot formation coupled with its significant ability to reduce surface tension of water, it has been credited with antifungal, antiviral, antitumor, insecticidal and antimycoplasma activities. These properties of therapeutic and commercial importance and its recent use as an enhanced oil recovery and a bioremediation agent make it a truly versatile biomolecule, the commercial potential of which could not be fully realized, particularly as a therapeutic agent, mainly because of its hemolytic property. This chapter thus addresses the issues related to the versatile nature of the most studied microbial surfactant, surfactin and its potential commercial and health-care applications. © 2010 Landes Bioscience and Springer Science+Business Media.

Paul B.,Indian Institute of Technology Kharagpur
Measurement: Journal of the International Measurement Confederation | Year: 2012

A simple apparatus for the simultaneous measurement of Seebeck coefficient (α) and electrical resistivity (ρ) in the temperature range 100-600 K, Hall coefficient (R H) and transverse Nernst-Ettingshausen coefficient (N) in the temperature range 300-600 K of the bar shaped samples has been fabricated. The instrument has been designed so simply that the sample can be easily mounted for the fast measurements of different thermoelectric parameters. The sample holder assembly of the apparatus has been designed so cleverly that any part of that section can be replaced in case of any damage; and so it can be regarded as a modular based system. The apparatus is relatively cheaper in cost and also portable. © 2011 Elsevier Ltd. All rights reserved.

Das A.,Nvidia | Hazra A.,STMicroelectronics | Banerjee S.,Indian Institute of Technology Kharagpur
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2010

This paper presents an architecture of the lifting-based running 3-D discrete wavelet transform (DWT), which is a powerful image and video compression algorithm. The proposed design is one of the first lifting based complete 3-D-DWT architectures without group of pictures restriction. The new computing technique based on analysis of lifting signal flow graph minimizes the storage requirement. This architecture enjoys reduced memory referencing and related low power consumption, low latency, and high throughput compared to those of earlier reported works. The proposed architecture has been successfully implemented on Xilinx Virtex-IV series field-programmable gate array, offering a speed of 321 MHz, making it suitable for real-time compression even with large frame dimensions. Moreover, the architecture is fully scalable beyond the present coherent Daubechies filterbank (9, 7). © 2006 IEEE.

Ghosh S.,Indian Institute of Technology Kharagpur
IEEE Antennas and Wireless Propagation Letters | Year: 2011

This letter proposes a planar crossed monopole antenna for ultrawideband application. The numerical simulations using Computer Simulation Technology (CST) transient solver and WIPL-D demonstrate that the impedance bandwidth of a rectangular monopole dramatically increases by including the cross plate. Parametric study on the crossed plate parameters is conducted to achieve the return loss of 10 dB over the desired frequency range (3.1-10.6 GHz). The stability of radiation pattern is also presented. The measured result for the return loss of a prototype antenna shows the same bandwidth as the simulated result. © 2011 IEEE.

Sarkar J.,Institute of Technology | Bhattacharyya S.,Indian Institute of Technology Kharagpur
International Journal of Refrigeration | Year: 2010

Thermodynamic analyses as well as optimization studies based on maximum cooling COP of a transcritical N2O cycle and both energetic and exergetic comparisons with CO2 cycle are presented in this article. Effects of superheating, internal heat exchanger and expansion turbine are studied as well. An expression for optimum discharge pressure has been developed. Variation trends of optimal parameters for the N2O system are similar to that of a CO2 system. The N2O cycle exhibits higher cooling COP, lower compressor pressure ratio and lower discharge pressure and temperature, and higher second law efficiency when compared to CO2 based systems; however, it is inferior in term of volumetric cooling capacity at the optimum condition. Effect of superheating in evaporator is negligible and effect of introducing an internal heat exchanger is moderate whereas effect of employing a work recovery turbine is significant on COP improvement and discharge pressure reduction at the optimal condition for both working fluids. © 2009 Elsevier Ltd and IIR.

Maiti S.,Indian Institute of Technology Kharagpur | Misra J.C.,Siksha O' Anusandhan University
International Journal of Engineering Science | Year: 2011

The paper deals with a theoretical study of the transport of a fluid in a channel, which takes place by the phenomenon of peristalsis. A mathematical analysis of the said problem has been presented. The analysis involves the application of a suitable perturbation technique. The velocity profile and the critical pressure for the occurrence of reflux are investigated with particular emphasis by using appropriate numerical methods. The effects of various parameters, such as Reynolds number, pressure gradient, porosity parameter, Darcy number, slip parameter, amplitude ratio and wave number on velocity and critical pressure for reflux are investigated in detail. The computed results are compared with a previous analytical work and an experimental investigation reported earlier in existing scientific literatures. The results of the present study are in conformity to both of them. The study has got some relevance to the physiological flow of bile in the common bile duct in a pathological state. It reveals that in the presence of gallstones, bile velocity increases as the value of the porosity parameter increases, while the critical pressure for reflux decreases as porosity increases. © 2011 Elsevier Ltd. All rights reserved.

Panda S.K.,National Institute of Technology Rourkela | Singh B.N.,Indian Institute of Technology Kharagpur
Aerospace Science and Technology | Year: 2013

Numerical investigation of nonlinear free vibration of thermally post-buckled laminated composite spherical shell panel embedded with shape memory alloy (SMA) fibre is presented. The mathematical model is proposed for the first time by taking the geometric nonlinearity in Green-Lagrange sense and the panel kinematics based on higher order shear deformation theory. In addition to the above the material nonlinearity in SMA fibres due to the temperature field is also considered in the present analysis. The system governing differential equation of the shell panel is obtained using Hamilton's principle. A direct iterative method in conjunction with nonlinear finite element is used to discretise and solve the system of equations. Effects of various parameters such as curvature ratios, thickness ratios, amplitude ratios, aspect ratios, support conditions, lamination schemes, SMA prestrains and SMA volume fractions on the nonlinear free vibration behaviour on post-buckled laminated panels are examined in detail and discussed. The results obtained are compared with those available in the literature. © 2013 Elsevier Masson SAS. All rights reserved.

Bhar A.,Motilal Nehru National Institute of Technology | Satsangi S.K.,Indian Institute of Technology Kharagpur
European Journal of Mechanics, A/Solids | Year: 2011

An efficient method for accurate evaluation of through-the-thickness distribution of transverse stresses in thick composite and sandwich laminates, using a displacement-based C0 higher-order shear deformation theory (HSDT), is presented. The technique involves a least square of error (LSE) method applied to the 3D equilibrium equations at the post-processing phase, after a primary finite element analysis is performed using the HSDT. This is distinctly different from the conventional method of integrating the 3D equilibrium equations, for transverse stress recovery in composite laminates during post-processing. Competence of the technique is demonstrated in the numerical examples through comparison with results from first-order shear deformation theory (FSDT), another HSDT and those from analytical and 3D elasticity solutions available in literature. © 2010 Elsevier Masson SAS. All rights reserved.

Goswami P.,Indian Institute of Technology Kharagpur
Microfluidics and Nanofluidics | Year: 2011

In this article, we investigate the implications of electroosmosis with interfacial slip on electrohydrodynamic transport in microchannels having complex (yet symmetric) cross-sectional shapes, by employing a generic semi-analytical approach. We also devise an approximate technique of flow rate prediction under these conditions, using a combined consideration of electroosmotic slip (under thin electrical double layer limits) and Navier slip conditions (originating out of confinement-induced hydrophobic interactions) at the fluid-solid interface. We further assess the effectiveness of the approximate solutions in perspective of the exact solutions, as a parametric function of the relative thickness of the electrical double layer with respect to the channel hydraulic diameter. We illustrate the underlying consequences through examples of elliptic, polygonal, point star-shaped, and annular microchannel cross sections. © Springer-Verlag 2011.

Racherla V.,Indian Institute of Technology Kharagpur
Sensors and Actuators, A: Physical | Year: 2011

An energy minimization approach is used to determine the electromechanical response of unimorphs composed of active and passive layers of "plain" dielectric polymers which exhibit electric field induced strains only due to Maxwell stresses. The deformed shape of the unimorph, its coupling efficiency, stall force and sensitivity of capacitance of the active layer to the tip force are determined as a direct function of the applied voltage difference, external forces, elastic moduli of the layers, dielectric constant of the active layer, and geometric characteristics of the unimorph. Expressions for tip displacement and stall force derived here are shown to describe, reasonably accurately, some of the experimental results published in literature. For the unimorphs considered here, it is shown that the sensing and actuating performance characteristics are directly proportional to the dielectric constant and the elastic compliance of the layers. While the sensing characteristic (sensitivity of capacitance of active layer to the tip force) is independent of the applied voltage, the actuating characteristics (tip displacement, coupling efficiency and stall force) are quadratically proportional to the applied voltage. The electromechanical coupling in dielectric polymers, occurring from Coulomb interaction between charges on the electrodes, is fundamentally different from that in piezoelectric, ionic, and electrostrictive polymers. Therefore, the models reported in literature, characterizing the deformation behavior of beam bending actuators based on these other electroactive polymers, are not applicable for the class of unimorphs considered in this work. © 2011 Elsevier B.V. All rights reserved.

Das J.,Indian Institute of Technology Kharagpur
Materials Science and Engineering A | Year: 2011

The microstructure of α-brass has been investigated at 98% and 200% of cryorolling (CR). Severe cryorolling introduces microscopic shear bands, forms primary and secondary twins, and the twin density increases with increase of plastic strain. Even though the average hardness values in CR200 (197 Hv) does not increase significantly than that of CR98 (189 Hv), but the hardness distribution become narrow in CR200 due to the narrow size distribution and refinement of twin lamellar spacing. The microscopic mechanism on the evolution of homogeneous nanostructure in α-brass has been reported. © 2011 Elsevier B.V.

Mandal S.M.,Indian Institute of Technology Kharagpur | Barbosa A.E.A.D.,Catholic University of Brasilia | Franco O.L.,Catholic University of Brasilia
Biotechnology Advances | Year: 2013

Lipopeptides are compounds that are formed by cyclic or short linear peptides linked with a lipid tail or other lipophilic molecules. Recently, several lipopeptides were characterized, showing surfactant, antimicrobial and cytotoxic activities. The properties of lipopeptides may lead to applications in diverse industrial fields including the pharmaceutical industry as conventional antibiotics; the cosmetic industry for dermatological product development due to surfactant and anti-wrinkle properties; in food production acting as emulsifiers in various foodstuffs; and also in the field of biotechnology as biosurfactants. Some lipopeptides have reached a commercial antibiotic status, such as daptomycin, caspofungin, micafungin, and anidulafungin. This will be the focus of this review. Moreover, the review presented here will focus on the biotechnological utilization of lipopeptides in different fields as well as the functional-structure relation, connecting recent aspects of synthesis and structure diversity. © 2013 Elsevier Inc.

Mondal S.,Jadavpur University | De S.,Indian Institute of Technology Kharagpur
Separation and Purification Technology | Year: 2010

A generalized theory has been proposed for a crossflow membrane filtration process, comprising of intermediate pore blocking followed by cake formation, in sequence. A phase space plot has been generated to identify the three filtration domains namely, pore blocking dominant, comparable resistances and cake dominating process. It is found that the crossflow velocity (in terms of steady state flux) has significant effect on the onset of the cake formation. It is observed that the intermediate pore blocking has very narrow region of dominance, so most experimental data are likely to lie in the cake controlling region. The operator can effectively control the characteristics of filtration by changing the crossflow velocity and transmembrane pressure. © 2010 Elsevier B.V. All rights reserved.

Bar S.,Indian Institute of Technology Kharagpur
Canadian Journal of Chemistry | Year: 2010

An efficient regio- and stereo-selective (>99:1) trans-bromohydrination (bromohydroxylation and bromomethoxylation) of alkenes including α,β-unsaturated carbonyl compounds with N-bromosuccinimide (NBS) has been achieved by using 1.0 mol% of N,N'-diarylthiourea catalyst.

Kumar G.V.P.,North Eastern Regional Institute of Science and Technology | Raheman H.,Indian Institute of Technology Kharagpur
Biosystems Engineering | Year: 2011

A 9.75 kW walk-behind type hand tractor powered 2-row fully automatic vegetable transplanter for individual paper pot seedlings was developed by considering the power availability, paper pot dimensions and space availability in the hand tractor after the complete removal of rotavator tillage assembly. It consisted of two sets of feeding conveyor, metering conveyor, seedling drop tube, furrow opener, soil covering device, an automatic feeding mechanism, a depth adjustment wheel and hitching arrangement. Horizontal slat-type chain conveyor was used as feeding conveyor and horizontal pusher type chain conveyor was used as metering conveyor. The automatic feeding mechanism, with a timing shaft, cam and clutch, was used to coordinate the working of feeding and metering conveyors. The vegetable transplanter carried 108 seedlings on two feeding conveyors in upright orientation, fed them to the metering conveyors and planted them in upright orientation in furrows. The performance of the vegetable transplanter was evaluated for transplanting tomato at 45 × 45 cm spacing in the field at a forward speed of 0.9 km h-1. Field capacity of the transplanter was found to be 0.026 ha h-1. It resulted in the saving of 68% labour and 80% time over the conventional method of manual transplanting. The planting rate of the transplanter was found to be 32 pot seedlings min-1 with 4% missed planting and 5% tilted planting. The soil covering efficiency of the developed vegetable transplanter was about 81% and the quality of transplanting was satisfactory. © 2011 IAgrE.

Singh A.,Indian Institute of Technology Kharagpur
Agricultural Water Management | Year: 2016

The intensification of irrigated agriculture is a prerequisite for fulfilling the rising food requirements of the burgeoning global population. But the expansion of irrigated agriculture causes the water resources problems in irrigated areas. The twin menace, i.e., waterlogging and soil salinization of irrigated agriculture can be managed by either adopting preventive measures which decrease the inflow or by employing remedial measures which increase the outflow of water and salt. Remote sensing and geographic information systems (GIS) are very useful tool and offer a good option to traditional techniques in monitoring and evaluation of waterlogged and saline areas. This paper presents an overview of the applications of remote sensing and GIS techniques for the management of water resources problems of irrigated agriculture. The indication and background of the water resources problems are provided. The integrated use of remote sensing and GIS techniques in the management of water resources problems are also discussed. Finally, the case studies of applications of integrated remote sensing and GIS approach and some conclusions are presented. © 2016 Elsevier B.V.

Jensen E.C.,University of California at Berkeley | Bhat B.P.,Indian Institute of Technology Kharagpur | Mathies R.A.,University of California at Berkeley
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2010

A digital microfluidic platform for the automation of quantitative, multi-step biomolecular assays is developed and optimized. The platform consists of a 2-dimensional array of microvalves that can be programmed to perform reagent routing, mixing, rinsing, serial dilution, and many other operations using nanolitre scale volumes of sample. Discrete transfer of fluid between microvalves is characterized using gravimetric flow analysis and optimized to achieve maximum efficiency. Protocols for on-chip reagent mixing and serial dilution are optimized to achieve linearity over a 1000-fold dilution range. These optimized programs are used to develop a rapid, quantitative assay for hydrogen peroxide, a biomarker of oxidative stress. A sub-micromolar limit of detection is demonstrated with an 8.5 min program runtime, thus establishing this platform as an effective tool for the automation of multi-step bioassays. The programmability of this system enables rapid development of diverse assay protocols on a common chip format. © The Royal Society of Chemistry 2010.

Shaikh R.,Indian Institute of Technology Kharagpur
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We show that it is possible to construct a wide class of Lorentzian wormholes in Eddington-inspired Born-Infeld gravity with a stress energy which does not violate the weak or null energy condition. The wormholes exist in a certain region of the parameter space. In fact, it is shown that there is a critical value of a parameter defined in our work, below which we have wormholes. Above the critical value, we have a regular black hole spacetime. We put a restriction on the equation of state parameter α (pθ=αρ) to have wormholes. We also put a lower limit on both the theory parameter |κ| and the throat radius, to restrict the tidal acceleration (at the throat) below one Earth gravity. As a special case of our general solution, we retrieve the wormhole supported by an electric field for a charge-to-mass ratio greater than the critical value (QM)c≈1.144. © 2015 American Physical Society.

Singh A.,Indian Institute of Technology Kharagpur
Land Use Policy | Year: 2015

Agriculture is the largest water user and consumes over 70% of the abstracted freshwater globally. The continuous increase in global population and simultaneous decrease in good quality water resources emphasize the need of using poor quality irrigation water for agricultural production. However, the injudicious use of poor quality irrigation water for crop production can be detrimental to the environment. Irrigation water quality has been considered as a serious environmental factor for the assessment of sustainable development during the last few decades. This paper highlights the need and advantages and disadvantages of long-term application of poor quality water on the soil and plant health. The overall environmental concerns of the approach are discussed in the paper which could be useful for all the stakeholders. © 2014 Elsevier Ltd.

Jana A.K.,Indian Institute of Technology Kharagpur
Energy Conversion and Management | Year: 2014

Progressive depletion of conventional fossil fuels with increasing energy demand and federal laws on environmental emissions have stimulated intensive research in improving energy efficiency of the existing fractionation units. In this light, the heat pump assisted distillation (HPAD) scheme has emerged as an attractive separation technology with great potential for energy saving. This paper aims at providing a state-of-the-art assessment of the research work carried out so far on heat pumping systems and identifies future challenges in this respect. At first, the HPAD technology is introduced with its past progresses that have centered upon column configuration, modeling, design and optimization, economic feasibility and experimental verification for steady state operation. Then the focus is turned to review the progress of a few emerging heat integration approaches that leads to motivate the researchers for further advancement of the HPAD scheme. Presenting the recently developed hybrid HPAD based heat integrated distillation configurations, the feasibility of heat pumping in batch processing is discussed. Finally the work highlights the opportunities and future challenges of the potential methodology. © 2013 Elsevier Ltd. All rights reserved.

Bandopadhyay A.,Advanced Technology Development Center | Chakraborty S.,Advanced Technology Development Center | Chakraborty S.,Indian Institute of Technology Kharagpur
Langmuir | Year: 2012

In this work, we investigate the effects of local permittivity variations, induced by a preferential orientation and exclusion of water dipoles close to channel walls, and the effects of finite-sized ions on the induced streaming potential in nanochannels. We make a detailed analysis of the underlying physicochemical interactions by considering combinations of cases where ions are considered to be point sized/finite sized and permittivity variation effects to be present/absent. By accounting for the dielectric friction (which in turn is a function of the local permittivity) in addition to the classical Stokes friction, we show that for high interfacial potentials and narrow confinements, the induced streaming potential field for the cases in which the polarization effects are considered for finite-sized ions is remarkably higher than for the cases in which the polarization effects are neglected. Thus, by coupling the nonlinear effects of finite-sized ions and water dipole polarization along with the dielectric friction, we open a new paradigm of streaming potential predictions for narrow fluidic confinements, bearing far-ranging scientific and technological consequences in nanoscale science and technology. © 2012 American Chemical Society.

Singh A.,Indian Institute of Technology Kharagpur
Land Use Policy | Year: 2015

The global population is continuously increasing and good quality land and water resources are simultaneously declining. This condition emphasizes the need of optimal allocation of these resources to fulfill the rising food requirements. This study presents the development and application of two management models for the seasonal optimal allocation of resources to maximize the net annual return of a canal command area of India. The models results show a reduction in rice and mustard crop areas against an increase in wheat, millet, cotton, and sugarcane crops. Under the optimal land and water allocation, the groundwater utilization increased, which in turn mitigated the waterlogging problems of the command area. The net annual return from the command area has increased by about 22%. The different optimal resource allocation strategies show an increase in net annual return with the increase in ranges of deviation from the existing conditions. The developed models can be used as a reliable decision aid for taking the farm and regional level decisions of optimal resources allocation and are able to solve the waterlogging problems of irrigated agriculture. The management models presented here are simple and can be used in any part of the world for maximizing the net agricultural return by mitigating the waterlogging problems in irrigated agriculture. However, under different hydro-geologic conditions, the constraints of the model may differ depending on the groundwater quality/quantity conditions and surface water/groundwater availability. © 2014 Elsevier Ltd.

Pradhan R.K.,Indian Institute of Technology Kharagpur
Journal of Health Management | Year: 2012

The present article examines the mediating role of psychological resilience in the relationship of positive affect with physical health and psychological well-being. The sample consists of 146 engineering, management and research students with an age range of 17-32 years (M = 22.93, SD = 3.67). Survey method was opted for data collection. Standard psychometric tools were used for collecting data on positive affect, psychological resilience, physical health, and psychological well-being. Positive affect was measured on the 'Positive Negative Affectivity Scale' (PANAS) constructed by Watson, Clark and Tellegen (1988). The 'Ego Resiliency Scale' by Block and Kremen (1996) was used to measure psychological resilience. Physical health and psychological well-being was assessed on the multi-dimensional health questionnaire proposed by Snell and Johnson (1997) and the psychological well-being scale by Ryff and Keyes (1995), respectively. The results revealed that psychological resilience significantly mediates between positive affect, and physical health and psychological well-being. The theoretical and practical implications of the study are discussed in the light of empirical findings. © 2012 Indian Institute of Health Management Research.

Singh A.,Indian Institute of Technology Kharagpur
Journal of Irrigation and Drainage Engineering | Year: 2014

The management of groundwater resources is a critical issue against the backdrop of the increasing water demand for agricultural, industrial, and domestic uses and dwindling water resources. Various simulation and optimization approaches have been used to solve the groundwater management problems. This paper presents an overview of the simulation and optimization modeling approaches used in groundwater resources conservation and management. The main objective of this review is to analyze simulation and optimization modeling approaches and to provide an assessment of their applications reported in literature. Conclusions are provided based on this evaluation, which could be useful for system managers and planners for selecting the suitable modeling approach for their specific uses. © 2013 American Society of Civil Engineers.

Sagaresan N.,Indian Institute of Technology Kharagpur
KSCE Journal of Civil Engineering | Year: 2012

Fracture in quasi-brittle materials such as concrete is accompanied by excessive cracking. Numerical analysis of concrete fracture is either based on smeared crack method or discrete crack method. Smeared crack methods are computationally less challenging than the discrete crack method. However, this simplicity brings loss of accuracy. We propose a novel simplified and highly efficient meshless method for discrete cracks and study fracture of concrete. The method exploits the advantages of smeared crack method and maintains the accuracy of discrete crack method. The discrete crack is modeled by set of discrete crack segments placed through the entire domain of influence of a node. We use Neo-Hooke material in the bulk material and a cohesive zone model once discrete cracks occur. We demonstrate the accuracy of the proposed meshless discrete crack method for complex problems involving mode-I and mixed mode failure. © 2012 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg.

Kapat S.,Indian Institute of Technology Kharagpur | Krein P.T.,University of Illinois at Urbana - Champaign
IEEE Transactions on Power Electronics | Year: 2012

Time optimal control (TOC) is a technique to provide fast transient recovery in dc-dc converters. Prior published approaches are incomplete in the formulation of TOC because they ignore voltage-deviation effects on inductor-current and load-current dynamics during a large-signal recovery. An accurate TOC algorithm based on capacitor current is presented. This method achieves minimum transient recovery time for load transients and tracking in a buck converter. The minimum recovery time is preserved even with a transient-detection delay. This control configuration ensures large-signal stability in a sense similar to that of sliding-mode control. The results are demonstrated in an experimental buck converter that uses a digital control algorithm. © 2011 IEEE.

Kapat S.,Indian Institute of Technology Kharagpur | Krein P.T.,University of Illinois at Urbana - Champaign
IEEE Transactions on Power Electronics | Year: 2012

The output voltage derivative term associated with a PID controller injects significant noise in a dc-dc converter. This is mainly due to the parasitic resistance and inductance of the output capacitor. Particularly, during a large-signal transient, noise injection significantly degrades phase margin. Although noise characteristics can be improved by reducing the cutoff frequency of the low-pass filter associated with the voltage derivative, this degrades the closed-loop bandwidth. A formulation of a PID controller is introduced to replace the output voltage derivative with information about the capacitor current, thus reducing noise injection. It is shown that this formulation preserves the fundamental principle of a PID controller and incorporates a load current feedforward, as well as inductor current dynamics. This can be helpful to further improve bandwidth and phase margin. The proposed method is shown to be equivalent to a voltage-mode-controlled buck converter and a current-mode-controlled boost converter with a PID controller in the voltage feedback loop. A buck converter prototype is tested, and the proposed algorithm is implemented using a field-programmable gate array. © 2011 IEEE.

Misra S.,Indian Institute of Technology Kharagpur | Singh S.,National Institute of Technology Durgapur
ACM Transactions on Sensor Networks | Year: 2012

Wireless Sensor Networks (WSN)-based surveillance applications necessitate tracking a target's trajectory with a high degree of precision. Further, target tracking schemes should consider energy consumption in these resource-constrained networks. In this work, we propose an energy-efficient target tracking algorithm, which minimizes the number of nodes in the network that should be activated for tracking the movement of the target. We model the movement of a target based on the Gauss Markov Mobility Model [Camp et al. 2002]. On detecting a target, the cluster head which detects it activates an optimal number of nodes within its cluster, so that these nodes start sensing the target. A Markov Decision Process (MDP)-based framework is designed to adaptively determine the optimal policy for selecting the nodes localized with each cluster. As the distance between the node and the target decreases, the Received Signal Strength (RSS) increases, thereby increasing the precision of the readings of sensing the target at each node. Simulations show that our proposed algorithm is energy-efficient. Also, the accuracy of the tracked trajectory varies between 50% to 1% over time. © 2012 ACM.

Sinha K.,Honeywell | Sinha B.P.,Indian Statistical Institute | Datta D.,Indian Institute of Technology Kharagpur
IEEE Transactions on Wireless Communications | Year: 2011

We propose a redundant radix based number (RBN) representation for encoding and transmitting data for applications which typically utilize low cost devices and demand low power operations with simple modulation techniques like ASK, OOK and FSK. Coupled with silent periods for communicating the digit zero, this encoded communication scheme, called as RBNSiZeComm, provides a highly energy-efficient technique for data transmission. Considering an n-bit data representation and assuming that each of the 2n binary strings is equally likely to occur, theoretically obtainable fraction of energy savings by using our proposed RBNSiZeComm transmission protocol is, on an average, 1 - n+2/4n. A hybrid modulation scheme using FSK and ASK with non-coherent detection based receiver for the RBNSiZeComm protocol has been presented. Assuming equal likelihood of all possible binary strings of a given length, there is nearly 53% savings in energy on an average at the transmitter relative to binary FSK, over additive white gaussian noise (AWGN) channels. Simulation results demonstrate that compared to binary FSK, our proposed implementation can extend the battery life of devices from about 33% to 62% on an average in applications like remote healthcare and wireless sensor networks for agriculture. © 2011 IEEE.

Roy R.,Indian Institute of Technology Kharagpur
Advanced Studies in Theoretical Physics | Year: 2014

An attempt to eliminate runaway solutions in classical electrodynamics is made. It is shown that a particle undergoing acceleration under the action of a constant external force is affected by radiation reaction. Three dimensional forms of the equation of motion and its relativistic generalization are attempted in ways to preserve not only the covariance of the theory but also the Newtonian concept of force in the low velocity limit. © 2014 Rajat Roy.

Roy P.,Birla Institute of Technology | Srivastava S.K.,Indian Institute of Technology Kharagpur
Journal of Materials Chemistry A | Year: 2015

High-energy consumption in our day-to-day life can be balanced not only by harvesting pollution-free renewable energy sources, but also requires proper storage and distribution of energy. In this regard, lithium ion batteries are currently considered as effective energy storage devices and involve the most active research. There exist several review articles dealing with various sections of LIBs, such as the anode, the cathode, electrolytes, electrode-electrolyte interface etc. However, the anode is considered to be a crucial component affecting the performance of LIBs as evident from the tremendous amount of current research work carried out in this area. In the last few years, advancements have been focused more on the fabrication of the nanostructured anode owing to its special properties, such as high surface area, short Li+ ion diffusion path length, high electron transportation rate etc. As the work in this area is growing very fast, the present review paper deliberates the recent developments of anode materials on the nanoscale. Different types of anode materials, such as carbon-based materials, alloys, Si-based materials, transition metal oxides, and transition metal chalcogenides, with their unique physical and electrochemical properties, are discussed. Various approaches to designing materials in the form of 0, 1 and 2D nanostructures and their effect of size and morphology on their performance as anode materials in LIBs are reviewed. Moreover, the article emphasizes smart approaches for making core-shell particles, nanoheterostructures, nanocomposites or nanohybrids with the combination of electrochemically active materials and conductive carbonaceous or electrochemically inactive materials to achieve LIBs with high capacity, high rate capability, and excellent cycling stability. We believe the review paper will provide an update for the reader regarding recent progress on nanostructured anode materials for LIBs. © The Royal Society of Chemistry 2015.

Ray M.C.,Indian Institute of Technology Kharagpur
Smart Materials and Structures | Year: 2010

A new hybrid piezoelectric composite (HPZC) reinforced with zigzag single-walled carbon nanotubes (CNTs) and piezoelectric fibers is proposed. The novel constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of piezoelectric fibers. A micromechanics model is derived to estimate the effective piezoelectric and elastic properties. It is found that the effective piezoelectric coefficient e 31 of the proposed HPZC, which accounts for the in-plane actuation, is significantly higher than that of the existing 1-3 piezoelectric composite without reinforcement with carbon nanotubes and the previously reported hybrid piezoelectric composite (Ray and Batra 2009 ASME J. Appl. Mech.76034503). © 2010 IOP Publishing Ltd.

Mukherjee S.,Emerson Network Power India Private Ltd | Poddar G.,Indian Institute of Technology Kharagpur
IEEE Transactions on Industry Applications | Year: 2010

The application of pulsewidth-modulated (PWM) voltages using two-level high-voltage inverters to a squirrel-cage induction motor (SQIM) can cause heating of rotor shaft, voltage spike across the motor terminals, etc. The increase in the number of steps of the motor voltage and hence decreasing the dv/dt applied to the machine terminals can be a solution to this problem. The existing topologies that generate this multistep voltage include cascading of a number of single-phase inverters or use of higher order multilevel inverters. In this paper, a topology with series connection of three-phase three-level inverters is proposed, which addresses the problems of medium-voltage drives. The design of the inverter topology and its various PWM techniques are presented in this paper. This inverter topology and its control are verified on a 7.5-hp SQIM drive. Experimental results validate the steady-state and dynamic performances of the drive. © 2010 IEEE.

Mittal R.,Indian Institute of Technology Kharagpur | Kansal A.,Microsoft | Chandra R.,Microsoft
Proceedings of the Annual International Conference on Mobile Computing and Networking, MOBICOM | Year: 2012

Battery life is a critical performance and user experience metric on mobile devices. However, it is difficult for app developers to measure the energy used by their apps, and to explore how energy use might change with conditions that vary outside of the developer's control such as network congestion, choice of mobile operator, and user settings for screen brightness. We present an energy emulation tool that allows developers to estimate the energy use for their mobile apps on their development workstation itself. The proposed techniques scale the emulated resources including the processing speed and network characteristics to match the app behavior to that on a real mobile device. We also enable exploring multiple operating conditions that the developers cannot easily reproduce in their lab. The estimation of energy relies on power models for various components, and we also add new power models for components not modeled in prior works such as AMOLED displays. We also present a prototype implementation of this tool and evaluate it through comparisons with real device energy measurements. Copyright © 2012 ACM.

Existing standard International methods to estimate fracture toughness of structural materials as documented in ASTM standard E-1820 are neither appropriate for material development due to the requirement of considerable volume nor suitable for process optimizations like deciding suitable heat treatment or for quality control of tonnage materials at the stage of production due to techno-economic reasons owing to their time-consuming nature. This report overviews several investigations often in their feasibility stage and aims to suggest a common solution to all these problems considering measurement of fracture toughness (KIVM) using chevron notched bend bar specimens with either rectangular cross-section (RC) or circular cross-section (CC). At the outset the theoretical background for obtaining KIVMRC and KIVMCC and the corresponding normalized stress intensity factors are discussed in order to illustrate the relatively simpler principle of estimation of fracture toughness. The usefulness of this technique is next illustrated using a number of examples related to: (a) design of small specimens for fracture toughness determination using this principle (b) optimization of the volume fraction of the constituent phases in dual phase steels, (c) design of heat treatment for cast rolls, (d) optimization of cryotreatment for tool steels and (e) study of the effect of inclusions on toughness characteristics of microalloyed steels. The examples related to (a) is for demonstrating the capability of this technique for material development, that related to (b), (c) and (d) are to illustrate its potential for process optimization and the one related to (e) is to illustrate its potential for quality control of tonnage materials. © (2013) Trans Tech Publications, Switzerland.

Kapat S.,Indian Institute of Technology Kharagpur | Shenoy P.S.,University of Illinois at Urbana - Champaign | Krein P.T.,University of Illinois at Urbana - Champaign
IEEE Transactions on Power Electronics | Year: 2012

The maximum closed-loop bandwidth of a dc-dc converter is restricted to a fraction of its switching frequency when governed by a conventional average-based pulsewidth modulation (PWM) controller. Even an advanced geometric control is limited by internal slew rates. The bandwidth can reach or exceed the switching frequency through converter augmentation; however, this requires a nonlinear control algorithm and circuit arrangements. This paper considers methods of augmentation and control for a fast buck converter. Conditions for time-optimal transient recovery are obtained for both instantaneous and delayed transient disturbance detection. Design tradeoffs and control issues related to augmentation are considered here. The main switch is controlled using a fixed frequency PWM current-mode control with load current feedforward, and augmented switches are controlled using frequency-limited bang-bang control based on a geometric approach. A small-signal model is obtained and extended control bandwidth is demonstrated. Fast transient recovery is achieved for both single- and two-resistance augmentation. A prototype augmented buck converter is tested. Output voltage and inductor current overshoot and undershoot can be lowered more than with previous methods. It is possible to achieve near-null response in the sense of ripple band to a large-signal transient. © 1986-2012 IEEE.

Chakraborti N.,Indian Institute of Technology Kharagpur
Materials Science and Technology (United Kingdom) | Year: 2014

The current state of the art of materials research using multi-objective genetic and evolutionary algorithms is briefly presented with critical analyses. The basic concepts of multi-objective optimisation and Pareto optimality are explained in simple terms and the advantages of an evolutionary approach are emphasised. Current materials related research in this area is summarised, focusing on the achievements to date and the specific needs for further improvement. © 2014 Institute of Materials, Minerals and Mining.

Singh A.K.,Indian Institute of Technology Kharagpur
Journal of Irrigation and Drainage Engineering | Year: 2014

The world population is increasing continuously and is expected to reach the 9.5 billion mark in 2050 from the current 7.1 billion. The importance of the groundwater resources is also increasing with the increase in population, because the quality and quantity of water resources are continuously declining because of urbanization, contamination, and climate change impact. Thus, under the current environment, the conservation and management of groundwater resources is a critical challenge for fulfilling the rising water demand for agricultural, industrial, and domestic uses. Various simulation and optimization approaches have been used to solve the groundwater management problems. Optimization methods have proved to be of great importance when used with simulation models, and the combined use of these two approaches gives the best results. The main objective of this review is to analyze combined uses of simulation and optimization modeling approaches and to provide an impression of their applications reported in literature. In addition to traditional optimization techniques, this paper highlights the application of computational intelligence techniques, such as artificial neural networks, response matrix approach, and multiobjective approach. Conclusions are drawn based on this review, which could be useful for system managers and planners for selecting the best suitable technique for their specific uses. © 2013 American Society of Civil Engineers.

Kim W.J.,Yeungnam University | Pradhan D.,Indian Institute of Technology Kharagpur | Sohn Y.,Yeungnam University
Journal of Materials Chemistry A | Year: 2013

Various indium oxide nanostructures of 1D-wires, 2D-hexagonal plates, 3D-cubes and donuts were synthesized, and their fundamental characteristics and CO oxidation activities were studied in detail. X-ray diffraction and Raman analysis revealed that the as-synthesized wires and cubes are orthorhombic InOOH and cubic In(OH)3, respectively. Upon annealing at 700°C in air, all the as-prepared samples were recrystallized to cubic In2O 3. The direct band gap of various as-synthesized nanostructures was estimated to be ∼2.7 eV from the UV-Vis absorption. Two broad photoluminescence peaks were found at 360 and 450 nm, which are attributed to the oxygen vacancies. The CO oxidation activities were in the order of hexagonal plates ≤ donuts < cubes < wires, tested by temperature-programmed reaction mass spectrometry. The difference in activity is explained on the basis of the surface area and oxygen vacancies of different nanostructures. In particular, the wires showed the CO oxidation onset at around 320°C, which is 280°C lower than that of hexagonal plates. The detailed morphology dependent properties and CO oxidation activities of various In2O 3 nanostructures presented in this study provide new insights into sensor, energy, and environmental applications. © 2013 The Royal Society of Chemistry.

Misra D.,Indian Institute of Technology Kharagpur
Phase Transitions | Year: 2014

The ground states of rare-earth nickelates (RNiO3) are antiferromagnetic insulators except LaNiO3, which is a strongly correlated metal. Rare-earth nickelates (R ≠ La) undergo a sharp transition from a high-temperature paramagnetic metal to a low-temperature antiferromagnetic insulator at finite temperature TMI that increases with the increase in atomic number of the rare-earth ions. The magnetic and resistive transitions are coupled for NdNiO3 and PrNiO3, but independent for the other members of the series. Whether the antiferromagnetic and insulating ground states of nickelates are due to charge ordering, or orbital ordering, it is a matter of current dispute. The present paper intends to explain the difference in the observed ground states of RNiO3 compounds, by calculating their band structure and density of states. The experimentally observed ground states of nickelates have been explained on the basis of mean-field calculation and the correlation effect is incorporated in the dynamical mean-field theory thereof. © 2014 Taylor & Francis.

Singh A.,Indian Institute of Technology Kharagpur
Science of the Total Environment | Year: 2014

The global population is increasing rapidly and expected to touch the 9.5 billion mark by 2050 from the current 7.2 billion. The management of the groundwater resources is a challenging task worldwide against the backdrop of the growing water demand for industrial, agricultural, and domestic uses and shrinking resources. Moreover, this task has been hampered significantly due to declining/rising groundwater levels and associated contamination. A broad range of solutions could be considered to address the aforementioned problems of groundwater management, but the effectiveness of all the solutions and their combinations cannot be verified with field experiments. Given their predictive capability, simulation models are often the only viable means of providing input to management decisions, as they can forecast the likely impacts of a particular water management strategy. This paper presents a comprehensive review on the simulation modeling applications for the management of groundwater resources. The past papers on the overview of groundwater simulation models, use of remote sensing and GIS in groundwater modeling, and application of simulation models in arid and semiarid regions are described in detail. Conclusions are drawn where gaps exist and more research needs to be focused. © 2014 Elsevier B.V.

Upadhyay S.,Indian Institute of Technology Kharagpur
International Journal of Theoretical Physics | Year: 2016

In this paper we study the third quantized super-group field cosmology, a model in multiverse scenario, in Batalin-Vilkovisky (BV) formulation. Further, we propose the superfield/super-antifield dependent BRST symmetry transformations. Within this formulation we establish connection between the two different solutions of the quantum master equation within the BV formulation. © 2016 Springer Science+Business Media New York

Kameswaran P.K.,University of KwaZulu - Natal | Narayana M.,University of KwaZulu - Natal | Sibanda P.,University of KwaZulu - Natal | Murthy P.V.S.N.,Indian Institute of Technology Kharagpur
International Journal of Heat and Mass Transfer | Year: 2012

We investigate the convective heat and mass transfer in nanofluid flow over a stretching sheet subject to hydromagnetic, viscous dissipation, chemical reaction and Soret effects. Two types of nanofluids, namely Cu-water and Ag-water were studied. A similarity transformation was used to obtain a system of non-linear ordinary differential equations, which was then solved numerically using the Matlab "bvp4c" function. Numerical results were obtained for the skin friction coefficient, Nusselt number, Sherwood number as well as for the velocity, temperature and concentration profiles for selected values of the governing parameters, such as the nanoparticle volume fraction φ, the magnetic parameter M. For a fixed Prandtl number Pr=6.2 (corresponding to water) and different values of the magnetic field parameter and the nanoparticle volume fraction, we have shown that a good agreement exists between the present results and those in the literature. It was shown that the Cu-water nanofluid exhibits higher wall heat and mass transfer rates as compared to a Ag-water nanofluid. The influence of a magnetic field is to reduce both wall heat and mass transfer rates. © 2012 Elsevier Ltd. All rights reserved.

Machiwal D.,Indian Central Arid Zone Research Institute | Jha M.K.,Indian Institute of Technology Kharagpur
Hydrological Processes | Year: 2014

The aim of this study was to investigate rainfall-groundwater dynamics over space and annual time scales in a hard-rock aquifer system of India by employing time series, geographic information system and geostatistical modelling techniques. Trends in 43-year (1965-2007) annual rainfall time series of ten rainfall stations and 16-year (1991-2006) pre-monsoon and post-monsoon groundwater levels of 140 sites were identified by using Mann-Kendall, Spearman rank order correlation and Kendall rank correlation tests. Trends were quantified by Kendall slope method. Furthermore, the study involves novelty of examining homogeneity of pre-monsoon and post-monsoon groundwater levels, for the first time, by applying seven tests. Regression analysis between rainfall and post-monsoon groundwater levels was performed. The pre-monsoon and post-monsoon groundwater levels for four periods - 1991-1994, 1995-1998, 1999-2002 and 2003-2006 - were subjected to geographic information system-based geostatistical modelling. The rainfall showed considerable spatiotemporal variations, with a declining trend at the Mavli rainfall station (p-value<0.05). The Levene's tests revealed spatial homogeneity of rainfall at α=0.05. Regression analyses indicated significant relationships (r2>0.5) between groundwater level and rainfall for eight rainfall stations. Non-homogeneity and declining trends in the groundwater level, attributed to anthropogenic and hydrologic factors, were found at 5-61 more sites in pre-monsoon compared with post-monsoon season. The groundwater declining rates in phyllite-schist, gneiss, schist and granite formations were found to be 0.18, 0.26, 0.21 and 0.14myear-1 and 0.13, 0.19, 0.16 and 0.02myear-1 during the pre-monsoon and post-monsoon seasons, respectively. The geostatistical analyses for four time periods revealed linkages between the rainfall and groundwater levels. © 2013 John Wiley & Sons, Ltd.

Nagal V.,Indian Institute of Technology Kharagpur
Refrigeration Science and Technology | Year: 2014

The cryogenic storage tanks T-83 and T-80 of argon and oxygen respectively at the 1290 TPD plant at Jamshedpur Tonnage, the ASU under the flagship of Linde India Ltd., were considered for the analysis. The primary losses in the tanks arise due to large thermal gradients across the cryogenic storage vessel, while the flash losses occurring during the transport of pure cryogenic gases from the Linde columns to their respective storage were also considered to be significant. A comparative evaluation of the recondensation system was performed for both the tanks in terms of thermodynamic and economic feasibility and the losses calculated were juxtaposed against the real-time values while the plant was in operational condition. Conclusively, alternate yet secondary sources of losses were identified to account for the deviations in theoretical calculations from the actual losses occurring, and associated engineering solutions were suggested to minimize them. Copyright © 2014 IIR/IIF.

Das D.,Bengal Engineering and Science University | Ray K.K.,Indian Institute of Technology Kharagpur
Philosophical Magazine Letters | Year: 2012

This study elucidates the underlying mechanism associated with microstructural modifications responsible for significant enhancement of wear resistance of tool steels by deep cryogenic treatment (DCT). It is demonstrated that DCT not only reduces the amount of retained austenite, but also conditions the martensite that, in turn, leads to the precipitation of higher amount of ultrafine secondary carbides. These favorable microstructural alterations by DCT enhance the resistance of tool steels against dynamic changes during wear resulting in improved wear resistance. © 2012 Copyright Taylor and Francis Group, LLC.

Das S.,University of Alberta | Chakraborty S.,Indian Institute of Technology Kharagpur | Mitra S.K.,University of Alberta
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

In this paper we delineate the consequences of field-dependent solvent polarization in the electric double layer (EDL) electrostatic potential distribution, and the effective EDL thickness in narrow nanofluidic confinements with thick (or overlapping) EDLs. The EDL, formed at the interface between a charged substrate and an electrolyte solution, induces a large electric field spanning across few nanometer distances from the interface. As a result, a polar solvent like water gets polarized, making its relative permittivity a function of the EDL electric field. This affects the overall EDL electrostatic potential distribution and most importantly, leads to a significant reduction of the effective EDL thickness, with the extent of the reduction being dictated by the value of field independent EDL thickness, strength of the solvent polarization, and the substrate-liquid interfacial electrostatic potential. Such a finding will necessitate redefining the classical EDL thickness, which will be of overwhelming significance in nanofluidic transport. © 2012 American Physical Society.

Biswal M.,Veer Surendra Sai University of Technology | Pati B.B.,Veer Surendra Sai University of Technology | Pradhan A.K.,Indian Institute of Technology Kharagpur
International Journal of Electrical Power and Energy Systems | Year: 2013

Distance relay protecting series compensated line has limitations with metal oxide varistor (MOV) operation, prefault system condition, high resistance fault and shunt capacitance. This paper proposes an adaptive first-zone distance protection scheme for line with fixed series compensation connected at one end using local measurements. Impedance offered by series capacitor and MOV combination is estimated using relay end fault current. The method has ability to compensate the error due to high resistance fault. The technique is tested for different system operating condition, level of compensation and fault resistance of a 400 kV series compensated line and simulated through EMTDC/PSCAD. Simulation results demonstrate the effectiveness of the proposed method. © 2013 Elsevier Ltd. All rights reserved.

Ghosh R.N.,Indian Institute of Technology Kharagpur
Procedia Engineering | Year: 2013

The paper critically examines the advantages and limitations of empirical and constitutive equation based approaches for creep strain prediction. While both may give similar predictions, the latter provides physical insight into the underlying mechanisms and suggests ways and means of improving creep resistance of high temperature materials. None of the methods as of now can estimate the reliability of material parameters required because of limited availability of creep strain time data. This is where more attention needs to be given otherwise practicing engineers would continue to depend on more readily available stress rupture data for life prediction of high temperature components. © 2013 The Authors.

Gontia N.K.,Junagadh Agricultural University | Tiwari K.N.,Indian Institute of Technology Kharagpur
Water Resources Management | Year: 2010

Remote sensing and Geographical Information System (GIS) techniques were used to estimate actual crop evapotranspiration of wheat crop grown in Tarafeni South Main Canal (TSMC) irrigation command of West Bengal State in India. The area under wheat crop was clipped from landuse/land cover map generated from Indian Remote Sensing Satellite P6 (IRS P6) image of January, 2004 for winter season 2003-04. The IRS P6 image and four wide field sensor (WiFS) images for different months of winter season were used to determine the Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) for area under wheat crop. The relationship between vegetation indices and crop coefficients (Kc) of wheat for corresponding months were developed. Based on these developed regression equations crop coefficient maps were generated for each month of wheat crop season. Monthly reference crop evapotranspiration (ETo) was estimated based on FAO-56, Penman-Monteith method. ETo was combined with spatially distributed Kc maps of different months of wheat crop season to generate crop evapotranspiration (ETc) maps of each month. The crop water demand of wheat estimated using spatially distributed ETc maps for months of December 2003, January 2004, February 2004, March 2004 (1st Fortnight) and March 2004 (2nd Fortnight) were found to be 3.98, 8.14, 4.66, 2.49, and 1.21 million cubic meter (MCM) respectively. Based on crop evapotranspiration the total crop water demand of wheat crop in irrigation command of TSMC was estimated as 20.48 MCM. © 2009 Springer Science+Business Media B.V.

Samanta B.,Indian Institute of Technology Kharagpur
Natural Resources Research | Year: 2010

This paper highlights the performance of a radial basis function (RBF) network for ore grade estimation in an offshore placer gold deposit. Several pertinent issues including RBF model construction, data division for model training, calibration and validation, and efficacy of the RBF network over the kriging and the multilayer perceptron models have been addressed in this study. For the construction of the RBF model, an orthogonal least-square algorithm (OLS) was used. The efficacy of this algorithm was testified against the random selection algorithm. It was found that OLS algorithm performed substantially better than the random selection algorithm. The model was trained using training data set, calibrated using calibration data set, and finally validated on the validation data set. However, for accurate performance measurement of the model, these three data sets should have similar statistical properties. To achieve the statistical similarity properties, an approach utilizing data segmentation and genetic algorithm was applied. A comparative evaluation of the RBF model against the kriging and the multilayer perceptron was then performed. It was seen that the RBF model produced estimates with the R 2 (coefficient of determination) value of 0.39 as against of 0.19 for the kriging and of 0.18 for the multilayer perceptron. © 2010 International Association for Mathematical Geology.

Cell to module (CTM) conversion loss, during Solar Photovoltaic (SPV) module manufacturing, in terms of wattage losses, at critical process steps Tabbing and Stringing (T&S) and Lamination have been analyzed and a comprehensive electrical and optical model presented. The relation between efficiency of the starting cells and CTM loss has been established. The optimization criteria of the T&S process, in terms of ribbon dimensions and the cell parameters, has also been described. CTM conversion loss/gain for lamination process has been modeled using refractive index and thicknesses of various thin film layers on cell with and without lamination. A guideline for selecting these parameters for obtaining optimized efficiency for laminated cells has been presented. The effect of added electrical resistance due to junction box and change of optical property due to anti reflection coating (ARC) on cover glass have also been presented in brief for completeness. Indoor as well as outdoor test data have been used for modules with ARC on cover glass. During outdoor test, measurements have been carried out with varying intensity and angle of incident of the light. T&S and lamination models have been validated by experiments conducted on single cell coupons. The power loss due to junction box and power gain due to ARC on cover glass has been done on full 60 cell modules. The models described here have been successfully used by the author for minimizing CTM conversion loss for two types of cells with known cell process parameters. © 2016 Elsevier Ltd.

Biligiri K.P.,Indian Institute of Technology Kharagpur | Way G.B.,Consulpav
Road Materials and Pavement Design | Year: 2014

The purpose of this research investigation was to conduct field and laboratory noise evaluation of 36 laboratory-blended and 49 field pavement cores encompassing 11 pavement types collected from Arizona and California in the USA and Sweden in Europe mainly to characterise their acoustical properties. Furthermore, a new and unique parameter referred to as damping acoustical measurement parameter (DAMP) was conceptualised and developed as part of this study to characterise noise-damping properties of the different road materials. Laboratory acoustical evaluation was performed on the samples covering nine conventional and modified asphalt and two non-asphaltic mixtures using the ultrasonic pulse velocity technique and Impedance (Z) was estimated. DAMP was established for the mixes which were inversely related to Z. Theoretically, lower Z and higher DAMP exemplified higher noise-damping capacity of the pavement. Amongst the asphaltic mixes, asphalt rubber friction course had the highest DAMP (∼20%) compared to the other mixes indicative of being the quietest pavement material, also confirmative of the field noise measurement findings. Within the non-asphaltic mixtures, poroelastic road surface showed the highest DAMP (37%), while Portland cement concrete exhibited the lowest DAMP (12%). © 2014, © 2014 Taylor & Francis.

Shekhar S.,Indian Defence Research And Development Laboratory | Sarkar R.,Indian Defence Research And Development Laboratory | Kar S.K.,Indian Institute of Technology Kharagpur | Bhattacharjee A.,Indian Defence Research And Development Laboratory
Materials and Design | Year: 2015

Ti-5Al-5V-5Mo-3Cr is one of the latest high strength β titanium alloys to be used for larger size components in aircraft structures replacing Ti-10V-2Fe-3Al. In the present study, a double VAR melted ingot was thermo-mechanically processed and it's microstructure and tensile properties determined as a function of β as well as α + β solution treatment and aging. The β solution treatment and aging resulted in higher strength and α + β solution treatment and aging resulted in an optimum combination of strength and ductility. Its aging behavior was studied as a function of time and temperature and corresponding microstructure as well as fractographs of tensile tested specimens were recorded. This systematic study should help in further modeling its mechanical behavior. © 2014 Elsevier Ltd.

Patra P.K.,Advanced Technology Development Center | Bhattacharya B.,Indian Institute of Technology Kharagpur
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

The widely used Nose-Hoover chain (NHC) thermostat in molecular dynamics simulations is generally believed to impart the canonical distribution as well as quasi- (i.e., space-filling) ergodicity on the thermostatted physical system (PS). Working with the standard single harmonic oscillator, we prove analytically that the two-chain Nose-Hoover thermostat with unequal thermostat masses approaches the standard Nose-Hoover dynamics, and hence the PS loses its canonical and quasiergodic nature. We also show through numerical simulations over substantially long times that for certain Poincaré sections, for both the equal and unequal thermostat mass cases, the bivariate distribution function of position and momentum (x,p) and of reservoir degrees of freedom (ξ,η) lose their Gaussian nature. Further, the four-dimensional x-p-ξ-η extended phase space exhibits two holes of nonzero measure. The NHC thermostat therefore does not generate the canonical distribution or preserve quasiergodicity for the PS. © 2014 American Physical Society.

Chowdhury K.,Indian Institute of Technology Kharagpur
Journal of Clinical Anesthesia | Year: 2014

There is an increase in the incidence of intraoperative fire in Indian hospitals. It is hypothesized that oxygen (O2) enrichment of air, is primarily responsible for most of the fires, particularly in intensive care units. As the amount of ignition energy needed to initiate fire reduces in the presence of higher O2 concentration, any heat or spark, may be the source of ignition when the air is O2-rich. The split air conditioner is the source of many such fires in the ICU, neonatal intensive care unit (NICU), and operating room (OR), though several other types of equipment used in hospitals have similar vulnerability. Indian hospitals need to make several changes in the arrangement of equipment and practice of handling O2 gas, as well as create awareness among hospital staff, doctors, and administrators. Recommendations for changes in system practice, which are in conformity with the National Fire Protection Association USA, are likely to be applicable in preventing fires at hospitals in all developing countries of the world with warm climates. © 2014 Elsevier Inc. All rights reserved.

Krithivasan S.,Jawaharlal Nehru Centre for Advanced Scientific Research | Wahal S.,Indian Institute of Technology Kharagpur | Ansumali S.,Jawaharlal Nehru Centre for Advanced Scientific Research
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2014

A solid-fluid boundary condition for the lattice Boltzmann (LB) method, which retains the simplicity of the bounce-back method and leads to positive definite populations similar to the diffusive boundary condition, is presented. As a refill algorithm, it is proposed that quasi-equilibrium distributions be used to model distributions at fluid nodes uncovered due to solid movement. The method is tested for flow past an impulsively started cylinder and demonstrates considerable enhancement in the accuracy of the unsteady force calculation at moderate and high Reynolds numbers. Furthermore, via simulations, we show that momentum exchange procedure used in LB to compute forces is not Galilean invariant. A modified momentum exchange procedure is proposed to reduce the errors due to violation of Galilean invariance. © 2014 American Physical Society.

Jha R.K.,Indian Institute of Information Technology, Design and Manufacturing | Chouhan R.,Indian Institute of Technology Kharagpur
Signal, Image and Video Processing | Year: 2014

In this paper, a dynamic stochastic resonance (DSR)-based technique in singular value domain for contrast enhancement of dark images has been presented. The internal noise due to the lack of illumination is utilized using a DSR iterative process to obtain enhancement in contrast, colorfulness as well as perceptual quality. DSR is a phenomenon that has been strategically induced and exploited and has been found to give remarkable response when applied on the singular values of a dark low-contrast image. When an image is represented as a summation of image layers comprising of eigen vectors and values, the singular values denote luminance information of each such image layer. By application of DSR on the singular values using the analogy of a bistable double-well potential model, each of the singular values is scaled to produce an image with enhanced contrast as well as visual quality. When compared with performance of some existing spatial domain enhancement techniques, the proposed DSR-SVD technique is found to give noteworthy better performance in terms of contrast enhancement factor, color enhancement factor and perceptual quality measure. © 2012 Springer-Verlag London Limited.

Mishra D.,Indian Institute of Technology Kharagpur
Journal of Medical Systems | Year: 2015

Smart card based authentication and key agreement schemes for telecare medicine information systems (TMIS) enable doctors, nurses, patients and health visitors to use smart cards for secure login to medical information systems. In recent years, several authentication and key agreement schemes have been proposed to present secure and efficient solution for TMIS. Most of the existing authentication schemes for TMIS have either higher computation overhead or are vulnerable to attacks. To reduce the computational overhead and enhance the security, Lee recently proposed an authentication and key agreement scheme using chaotic maps for TMIS. Xu et al. also proposed a password based authentication and key agreement scheme for TMIS using elliptic curve cryptography. Both the schemes provide better efficiency from the conventional public key cryptography based schemes. These schemes are important as they present an efficient solution for TMIS. We analyze the security of both Lee’s scheme and Xu et al.’s schemes. Unfortunately, we identify that both the schemes are vulnerable to denial of service attack. To understand the security failures of these cryptographic schemes which are the key of patching existing schemes and designing future schemes, we demonstrate the security loopholes of Lee’s scheme and Xu et al.’s scheme in this paper. © 2015, Springer Science+Business Media New York.

Tripathy P.P.,Indian Institute of Technology Kharagpur
Journal of Food Science and Technology | Year: 2015

Drying experiments have been performed with potato cylinders and slices using a laboratory scale designed natural convection mixed-mode solar dryer. The drying data were fitted to eight different mathematical models to predict the drying kinetics, and the validity of these models were evaluated statistically through coefficient of determination (R2), root mean square error (RMSE) and reduced chi-square (χ2). The present investigation showed that amongst all the mathematical models studied, the Modified Page model was in good agreement with the experimental drying data for both potato cylinders and slices. A mathematical framework has been proposed to estimate the performance of the food dryer in terms of net CO2 emissions mitigation potential along with unit cost of CO2 mitigation arising because of replacement of different fossil fuels by renewable solar energy. For each fossil fuel replaced, the gross annual amount of CO2 as well as net amount of annual CO2 emissions mitigation potential considering CO2 emissions embodied in the manufacture of mixed-mode solar dryer has been estimated. The CO2 mitigation potential and amount of fossil fuels saved while drying potato samples were found to be the maximum for coal followed by light diesel oil and natural gas. It was inferred from the present study that by the year 2020, 23 % of CO2 emissions can be mitigated by the use of mixed-mode solar dryer for drying of agricultural products. © 2013, Association of Food Scientists & Technologists (India).

Sehgal V.,Birla Institute of Technology | Sahay R.R.,Birla Institute of Technology | Chatterjee C.,Indian Institute of Technology Kharagpur
Water Resources Management | Year: 2014

Wavelet based flood forecasting models are known to perform better than conventional models, yet the effect of the way wavelet components are combined to develop a model on the forecasting performance, is inadequately investigated. To demonstrate this, two types of wavelet- adaptive neuro-fuzzy inference system (WANFIS), i.e. WANFIS-split data model (WANFIS-SD) and WANFIS-modified time series model (WANFIS-MS) are developed to forecast river water levels with 1-day lead time. To develop these models, first the original level time series (OLTS) is decomposed into discrete wavelet components (DWCs) by discrete wavelet transform (DWT) upto three resolution levels. In WANFIS-SD, all wavelet components are used as inputs while WANFIS-MS ignores the noise wavelet components and utilizes only the effective wavelet components. The effectiveness of the developed models are evaluated through application to two Indian rivers, Kamla and Kosi, which vary significantly in their catchment area and flow patterns. The proposed models are found to forecast river water levels accurately. On comparison, the WANFIS-SD is found to perform better than WANFIS-MS for high flood levels. © 2014 Springer Science+Business Media Dordrecht.

Datta N.,Indian Institute of Technology Kharagpur
Ocean Engineering | Year: 2015

This paper studies a continuous, elastic model of an ocean tower, partially submerged in water, undergoing free transverse vibration in a plane. The tower is modeled as a non-uniform Timoshenko beam which is supported by an eccentric tip mass on one end and a non-classical damped foundation on the other. The foundation is modeled as a combination of translational and rotational springs and dampers. The effect of shear deformation and rotary inertia is included in the analysis. The free vibration equation is derived using Hamilton's variational principle based on two approaches, Rayleigh Ritz Method (RRM) and Finite Element Method (FEM), which show a good agreement in results. The computational efficiency of RRM over FEM is shown using a convergence study. Finally, a parametric study is done to demonstrate the dependence of natural frequency on different configurations of the tower. © 2015 Elsevier Ltd.

Prasad M.V.D.,Advanced Technology Development Center | Bhattacharya B.,Indian Institute of Technology Kharagpur
Nano Letters | Year: 2016

Using phonon wave packet molecular dynamics simulations, we find that anomalous longitudinal acoustic (LA) mode phonon scattering in low to moderate energy ranges is responsible for initiating thermophoretic motion in carbon nanotube oscillators. The repeated scattering of a single mode LA phonon wave packet near the ends of the inner nanotube provides a net unbalanced force that, if large enough, initiates thermophoresis. By applying a coherent phonon pulse on the outer tube, which generalizes the single mode phonon wave packet, we are able to achieve thermophoresis in a carbon nanotube oscillator. We also find the nature of the unbalanced force on end-atoms to be qualitatively similar to that under an imposed thermal gradient. The thermodiffusion coefficient obtained for a range of thermal gradients and core lengths suggest that LA phonon scattering is the dominant mechanism for thermophoresis in longer cores, whereas for shorter cores, it is the highly diffusive mechanism that provides the effective force. © 2016 American Chemical Society.

Singh A.,Indian Institute of Technology Kharagpur
Ecological Indicators | Year: 2014

The seawater intrusion is a widespread environmental problem of coastal aquifers where more than two third of the world's population lives. The indiscriminate and unplanned groundwater withdrawal for fulfilling the growing freshwater needs of coastal regions causes this problem. Computer-based models are useful tools for achieving the optimal solution of seawater intrusion management problems. Various simulation and optimization modeling approaches have been used to solve the problems. Optimization approaches have been shown to be of great importance when combined with simulation models. A review on the combined applications of simulation and optimization modeling for the seawater intrusion management of the coastal aquifers are done and is presented in this paper. The reviews revealed that the simulation-optimization modeling approach is very suitable for achieving an optimal solution of seawater intrusion management problems even with a large number of variables. It is recommended that the future research should be directed toward improving the long-term hydraulic assessment by collecting and analyzing widespread spatial data, which can be done by increasing the observation and monitoring networks. The coupling of socioeconomic aspects in the seawater intrusion modeling would be another aspect which could be included in the future studies. © 2014 Elsevier Ltd. All rights reserved.

Lal A.,Sardar Vallabhbhai National Institute of Technology, Surat | Singh B.N.,Indian Institute of Technology Kharagpur | Patel D.,Sardar Vallabhbhai National Institute of Technology, Surat
Composite Structures | Year: 2012

This paper present the second ordered statistics of first-ply failure response of laminated composite plate with random material properties under random loading. The basic formulation is based on higher order shear deformation plate theory (HSDT) with the geometrically nonlinearity in the von-Karman. The direct iterative based C 0 nonlinear finite element method combined with mean centered first order perturbation technique developed by the authors are extended and successfully applied nonlinearity for failure problem with a reasonable accuracy to predict the second order statistics (standard deviation) of first-ply failure response using Tsai-Wu and Hoffman failure criterion with macroscopic analysis. Typical numerical results for various combinations of boundary conditions, plate thickness ratios, aspect ratios, laminates scheme and layers, elastic modulus ratios have been presented to illustrate the application of developed procedure. Some new results are presented and examined which clearly demonstrated the importance of the randomness in the system parameters in the failure response of the structures subjected to transverse loadings. © 2011 Elsevier Ltd.

Mitra S.,Indian Institute of Technology Kharagpur | Washington S.,Queensland University of Technology
Accident Analysis and Prevention | Year: 2012

Advances in safety research - trying to improve the collective understanding of motor vehicle crash causes and contributing factors - rest upon the pursuit of numerous lines of research inquiry. The research community has focused considerable attention on analytical methods development (negative binomial models, simultaneous equations, etc.), on better experimental designs (before-after studies, comparison sites, etc.), on improving exposure measures, and on model specification improvements (additive terms, non-linear relations, etc.). One might logically seek to know which lines of inquiry might provide the most significant improvements in understanding crash causation and/or prediction. It is the contention of this paper that the exclusion of important variables (causal or surrogate measures of causal variables) cause omitted variable bias in model estimation and is an important and neglected line of inquiry in safety research. In particular, spatially related variables are often difficult to collect and omitted from crash models - but offer significant opportunities to better understand contributing factors and/or causes of crashes. This study examines the role of important variables (other than Average Annual Daily Traffic (AADT)) that are generally omitted from intersection crash prediction models. In addition to the geometric and traffic regulatory information of intersection, the proposed model includes many spatial factors such as local influences of weather, sun glare, proximity to drinking establishments, and proximity to schools - representing a mix of potential environmental and human factors that are theoretically important, but rarely used. Results suggest that these variables in addition to AADT have significant explanatory power, and their exclusion leads to omitted variable bias. Provided is evidence that variable exclusion overstates the effect of minor road AADT by as much as 40% and major road AADT by 14%. © 2012 Elsevier Ltd.

Neogi A.,Advanced Technology Development Center | Mitra N.,Indian Institute of Technology Kharagpur
Physics of Fluids | Year: 2016

Molecular dynamics simulations were carried out using numerous force potentials to investigate the shock induced phenomenon of pure bulk liquid water. Partial phase transition was observed at single shock velocity of 4.0 km/s without requirement of any external nucleators. Change in thermodynamic variables along with radial distribution function plots and spectral analysis revealed for the first time in the literature, within the context of molecular dynamic simulations, the thermodynamic pathway leading to formation of ice VII from liquid water on shock loading. The study also revealed information for the first time in the literature about the statistical time-frame after passage of shock in which ice VII formation can be observed and variations in degree of crystallinity of the sample over the entire simulation time of 100 ns. © 2016 AIP Publishing LLC.

Mitra N.,Indian Institute of Technology Kharagpur
Composite Structures | Year: 2010

Researchers have developed several measures to improve shear resistance capacity of sandwich structures composed of thin composite face sheets of Eglass/epoxy and low density PVC foam core, but these methodologies are either costly or result in damage to the sandwich composites before being placed for production. A novel, innovative cost-effective methodology of introducing fiberglass shear keys attached to face skins to improve the stiffness and strength of the sandwich composite panel is being proposed in this manuscript. Manufacturing of the sandwich composite panels along with experimental and numerical investigations have been performed in this manuscript to demonstrate the potential of the proposed simple methodology which can be utilized for shear-sensitive design and analysis of sandwich composite structures and/or components. A parametric study has also been carried out to determine the effect of change in shape, size, spacing and material of the shear keys on the sandwich composite panel global response. © 2009 Elsevier Ltd. All rights reserved.

Chakraborty D.,Indian Institute of Technology Kharagpur | Choudhury D.,Indian Institute of Technology Bombay
Applied Ocean Research | Year: 2014

The stability analysis has been performed for a generalized non-vertical waterfront retaining wall supporting an inclined backfill and subjected to the seismic forces. The limit equilibrium method has been used to obtain the factor of safety against sliding mode of failure. The advanced pseudo-dynamic approach has been implemented for the determination of the seismic active earth pressure and the wall inertia force. In the stability analysis, along with the hydrostatic pressures the hydrodynamic pressures have also been taken into consideration. The results clearly indicate about the adverse effect of earthquake on the sliding stability of waterfront retaining wall. It has been found that the parameters like seismic accelerations in both horizontal and vertical directions, soil and wall friction angles, time period, pore pressure ratio, wall batter and ground inclination have considerable effect on the stability of the non-vertical waterfront retaining wall when it is subjected to an earthquake. Comparison of results with the available results in literature for an ideal case of perfectly vertical waterfront retaining wall supporting horizontal backfill has shown nice agreement. It is expected that the proposed design charts and tables presented in this paper would be helpful for the engineers to design the waterfront retaining wall in an earthquake prone area. © 2014 Elsevier Ltd.

Mukherjee D.,Indian Institute of Technology Kharagpur | Ray S.,Indian Statistical Institute
Palaeontology | Year: 2014

A new species of the rhynchosaur genus Hyperodapedon, namely H. tikiensis, is described from well-preserved skeletal elements that were collected from the Upper Triassic Tiki Formation of India. Hyperodapedon tikiensis is diagnosed on the basis of several cranial and postcranial features including longer than wide basipterygoid process, crest-shaped maxillary cross section lateral to the main longitudinal groove, deeply excavated neural arches of mid-dorsal vertebrae, long scapular blade, a pronounced deltopectoral crest, proximal humeral end much broader than distal end, iliac length greater than iliac height, equal pre- and postacetabular iliac lengths and circular femoral cross section. Two distinct morphotypes of the maxillary tooth plates can be discerned, which are attributed to ontogenetic variations. A maximum-parsimony analysis was carried out to show that the order Rhynchosauria is characterized by nine cranial and one postcranial character states. The analysis reveals that Otischalkia elderae is invalid and the basal forms, Howesia and Mesosuchus, are closely related. The Mid-Triassic genus Ammorhynchus is more derived and forms a sister group to the Late Triassic subfamily Hyperodapedontinae. Isalorhynchus and Teyumbaita are basal to the pandemic genus Hyperodapedon. Twenty-four characters that are not homoplasious document major patterns of skeletal evolution in rhynchosaurs. From laterally oriented scapula and slender propodials, the postcranial skeleton evolved into a more robust form as is evident from nearly vertical scapula and increase in the robustness of the propodials. Shortening of the femur is noted in the derived Late Triassic forms as exemplified in Hyperodapedon gordoni, Hyperodapedon huxleyi and H. tikiensis. © The Palaeontological Association.

Prabhu K.,Indian Institute of Technology Kharagpur | Dadhich N.,Inter-University Center for Astronomy and Astrophysics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

We investigate the properties of the event horizon and static limit for a charged rotating black hole solution of minimal supergravity theory in (1+4) dimension. Unlike the four-dimensional case, there are in general two rotations, and they couple to both mass and charge. This gives rise to much richer structure to ergosphere leading to energy extraction even for axial fall. Another interesting feature is that the metric in this case is sensitive to the sign of the Maxwell charge. © 2010 The American Physical Society.

Sen P.K.,Indian Institute of Technology Kharagpur
International Materials Reviews | Year: 2010

The global data on manganese reserves apparently indicate that there is no resource crunch. However, a large part of the terrestrial deposits (80%) do not meet the grade requirement for efficient production of high quality ferroalloys required for steel making. The marine mineral deposits, which have attracted the greatest interest as alternative exploitable source for this element, are the deep-sea manganese nodules. If efficient schemes for manganese recovery values are put in place, the marine deposits would rather be classified as manganese ores which would have remarkable advantages over terrestrial low grade deposits because of by product recovery of copper, nickel and cobalt. Specific processing schemes for production of manganese alloys and compounds are critically discussed in this overview. The production of high purity Cu, Ni and Co using solvent extraction has also been reviewed. Optimisation approaches for sea nodules processing schemes have been analysed. Various other potential applications of sea nodules have been brought out. The possibility of integration of the processing schemes with land based production processes are likely to render sea nodules as useful alternative sources for metals and other value added materials of the future. © 2010 Institute of Materials, Minerals and Mining and ASM International Published by Maney for the Institute and ASM International.

Tyagi B.,University of Stockholm | Satyanarayana A.N.V.,Indian Institute of Technology Kharagpur
International Journal of Climatology | Year: 2014

An attempt has been made to differentiate percentage contribution of coherent structures (CS) in the turbulent fluxes of heat and momentum during thunderstorm days (TD) and non-thunderstorm days (NTD) at two tropical sites. Pre-monsoon months (Marcha to May) fast response data (10Hz) of wind and temperature at Kharagpur (22°30′N, 87°20′E) for years 2007, 2009, and 2010, and at Ranchi (23°25′N, 85°26′E) for years 2008-2010 have been used. The contributions were calculated after decomposing the time series using wavelet technique by two methods: (1) the method of quadrant analysis for each scale, and (2) the method of zero-crossing. Contributions of CS in momentum flux are higher in TD than NTD, whereas for heat flux CS contribution is higher for NTD to that of TD at both sites; however, values are different at both sites and by each method as well. Significant percentages of contributions of CS to the total flux are noticed at both the sites. © 2013 Royal Meteorological Society.

Odelu V.,Rajiv Gandhi University | Das A.K.,International Institute of Information Technology, Hyderabad | Goswami A.,Indian Institute of Technology Kharagpur
Information Sciences | Year: 2014

Lo et al. (2011) proposed an efficient key assignment scheme for access control in a large leaf class hierarchy where the alternations in leaf classes are more frequent than in non-leaf classes in the hierarchy. Their scheme is based on the public-key cryptosystem and hash function where operations like modular exponentiations are very much costly compared to symmetric-key encryptions and decryptions, and hash computations. Their scheme performs better than the previously proposed schemes. However, in this paper, we show that Lo et al.'s scheme fails to preserve the forward security property where a security class Cx can also derive the secret keys of its successor classes Cj's even after deleting the security class Cx from the hierarchy. We aim to propose a new key management scheme for dynamic access control in a large leaf class hierarchy, which makes use of symmetric-key cryptosystem and one-way hash function. We show that our scheme requires significantly less storage and computational overheads as compared to Lo et al.'s scheme and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against all possible attacks including the forward security. In addition, our scheme supports efficiently dynamic access control problems compared to Lo et al.'s scheme and other related schemes. Thus, higher security along with low storage and computational costs make our scheme more suitable for practical applications compared to other schemes. © 2013 Elsevier Inc. All rights reserved.

Thakur A.K.,Indian Institute of Technology Kharagpur | Hashmi S.A.,University of Delhi
Solid State Ionics | Year: 2010

Fourier transform infra-red (FTIR) spectroscopic studies have been carried out to probe, at the microscopic level, the effect of filler concentration on poly ethylene oxide (PEO) based composite polymer electrolytes complexed with sodium salts (NaClO4 and NaI) dispersed with inorganic fillers, Na2SiO3 and SnO2. The FTIR results correlate very well with macroscopic changes such as glass transition temperature (T g), electrical conductivity and mechanical properties in the composite polymeric systems due to the dispersion of filler particles. The striking observation of the two maxima feature in electrical conductivity (σ) variation versus filler concentration is satisfactorily explained in terms of variation of Tg and degree of crystallinity of the polymer composites. Although, few such observations have been reported by other earlier workers in some composite systems no explanation is available at the microscopic level. A mechanism at microscopic level from FTIR results involving ion-polymer, ion-ion, ion-filler and polymer-filler interactions has been proposed by us to explain the variations of σ and Tg as a function of filler concentration. The initial increase in free anions due to the interaction of fillers with ether oxygen of PEO and/or ClO4- anions followed by ion-pair formation results in the first maxima in the variations of σ vs. filler concentration. The second maxima results from the additional generation of free anions due to weakening of filler-anion interactions followed by the cluster formation on addition of fillers. The improvements in mechanical properties of the composite polymer electrolytes have also been explained on the basis of the proposed mechanism. © 2010 Elsevier B.V. All rights reserved.

Mamtani M.A.,Indian Institute of Technology Kharagpur
Tectonophysics | Year: 2014

A concept is presented to quantify vorticity using magnetic fabric data determined from anisotropy of magnetic susceptibility (AMS) analysis in syntectonic granites, whose emplacement is synchronous with tectonics of adjacent shear zones. The latter is considered to define the direction of extensional flow apophysis (Ae). It is suggested that the magnetic foliation traces the direction of maximum instantaneous stretching axis during the final stage of ductile deformation. Hence, the angle between mean orientation of magnetic foliation and Ae gives the kinematic vorticity number (Wn). This concept is tested in two granites from India - Godhra Granite (western India) and Chakradharpur Granitoid (eastern India). The analysis explains the kinematics of fabric development within the granites and also the evolution of structural elements in the surrounding rocks. It is also suggested that in cases where granite margins get mylonitized synchronously with tectonic activity along adjacent shear zones, the angle between mean magnetic foliation of the granite margin samples and the shear zone can help calculate Wn. The example of Malanjkhand Granite (central India) is discussed to highlight this. Using magnetic fabric, a value of Wn=0.98 is recorded for granite margin samples implying their deformation by dominantly simple shear. Oblique quartz foliation recorded on the microscale in the granite margin samples yields Wn=0.94, which is similar to the value obtained using AMS. It is thus concluded that magnetic fabric provides a possibility to quantify vorticity in syntectonic granites in 2-dimension. © 2014 Elsevier B.V.

Pratihar D.K.,Indian Institute of Technology Kharagpur
International Journal of Advanced Manufacturing Technology | Year: 2015

This paper presents a review on soft computing-based expert systems developed to establish input-output relationships of various manufacturing processes. To determine these relationships, both fuzzy logic- and neural network-based approaches were tried. Reasonably good results were obtained using the developed approaches. However, there is a chance of further improvement of the results. The scopes for future study have also been discussed. © 2015 Springer-Verlag London

Mishra D.,Indian Institute of Technology Kharagpur
Journal of Medical Systems | Year: 2015

Telecare medical information systems (TMIS) enable healthcare delivery services. However, access of these services via public channel raises security and privacy issues. In recent years, several smart card based authentication schemes have been introduced to ensure secure and authorized communication between remote entities over the public channel for the (TMIS). We analyze the security of some of the recently proposed authentication schemes of Lin, Xie et al., Cao and Zhai, and Wu and Xu’s for TMIS. Unfortunately, we identify that these schemes failed to satisfy desirable security attributes. In this article we briefly discuss four dynamic ID-based authentication schemes and demonstrate their failure to satisfy desirable security attributes. The study is aimed to demonstrate how inefficient password change phase can lead to denial of server scenario for an authorized user, and how an inefficient login phase causes the communication and computational overhead and decrease the performance of the system. Moreover, we show the vulnerability of Cao and Zhai’s scheme to known session specific temporary information attack, vulnerability of Wu and Xu’s scheme to off-line password guessing attack, and vulnerability of Xie et al.’s scheme to untraceable on-line password guessing attack. © 2014, Springer Science+Business Media New York.

Kim W.J.,Yeungnam University | Pradhan D.,Indian Institute of Technology Kharagpur | Min B.-K.,Yeungnam University | Sohn Y.,Yeungnam University
Applied Catalysis B: Environmental | Year: 2014

BiOCl and BiOClxI1-x were synthesized in two different solvents of ethylene glycol (EG) and water, and their natures were examined by scanning electron microscopy (SEM), electron transmission microscopy (TEM), X-ray diffraction, UV-vis absorption and Raman, Fourier-transform infrared, and photoluminescence spectroscopy. The Ag and Au-doping effects on the fundamental nature and photocatalytic activity of BiOCl and BiOClxI1-x were investigated in detail. SEM revealed that 3D flower-like and 2D plate-like microstructures were formed with EG and water solvents, respectively. The as-synthesized samples were tested for the adsorption and photocatalytic degradation of methyl orange and Rhodamine B, with the flower-like 3D-structure showing superior adsorption performance relative to the stacked 2D plate-like structures. Upon introducing iodine into BiOCl, we observed a dramatic increase in the adsorption ability and Brunauer-Emmett-Teller surface area, with an order of 2D BiOCl<3D BiOCl≪BiOClxI1-x (x=0.8, 0.6 and 0.4). The dye degradation performance was further markedly enhanced under irradiation by visible light. However, a small amount of Ag and Au-doping drastically negated the adsorption and photocatalytic performance. The photocatalytic mechanism was elucidated by an indirect chemical probe method using active species scavengers, and photoluminescence spectroscopy. On the basis of the results obtained, we propose a dye-sensitized photodegradation mechanism, and the active species play roles in the order of OH≪O2 -≈h+ under visible light irradiation. © 2013 Elsevier B.V.

Kakade A.B.,Rajarambapu Institute of Technology | Ghosh B.,Indian Institute of Technology Kharagpur
IEEE Transactions on Antennas and Propagation | Year: 2011

In this paper, a coax-probe excited multilayer dielectric resonator antenna (DRA) structure is rigorously analyzed from the modal perspective. The full-wave Green's function approach is presented for the analysis of such multilayer structures with an arbitrary number of layers with greatly reduced computational overhead. Additional reduction in computation time is demonstrated for a centered probe. Also, the modes of the multilayer DRA can be identified from the analysis, which can be used to explain the broadband nature of the coupling. The layer permittivities are optimized for broadband operation of the coax-fed DRA. The bandwidth enhancement for a centered and offset probe is seen to be due to a combination of several DRA modes and the probe resonance. Frequency tuning of the antenna structure is also demonstrated by exciting the antenna at a higher order mode, maintaining the broadband characteristics. The radiation characteristics of the antenna are also investigated. © 2011 IEEE.

Pradhan P.M.,Indian Institute of Technology Kharagpur
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We study oscillating string solutions in the Klebanov-Witten and its non-Abelian T-dual background dualized along an SU(2) isometry. We find the string energy as the function of the oscillation number and angular momentum. We show that for a particular set of T-dual coordinates both the backgrounds have equal string states. We also study the string states where the strings are expanding and contracting in the T-dual coordinate direction. We expect the presence of the superconformal field theory dual operators whose anomalous dimensions depend on the T-dual coordinate. © 2014 American Physical Society.

Jana S.,Indian Institute of Technology Kharagpur
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

A perfect fluid, spatially flat cosmology in a f(T) model, derived from a recently proposed general Born-Infeld-type theory of gravity is studied. Four-dimensional cosmological solutions are obtained assuming the equation of state p=ωρ. For a positive value of λ (a parameter in the theory) the solution is singular (of the big bang type) but may have accelerated expansion at an early stage. For λ<0 there exists a nonzero minimum scale factor and a finite maximum value of the energy density, but the curvature scalar diverges. Interestingly, for λ<0, the Universe may undergo an eternal accelerated expansion with a de Sitter expansion phase at late times. We find these features without considering any extra matter field or even negative pressure. Fitting our model with supernova data we find that the simplest dust model (p=0), with λ>0, is able to generate acceleration and fits well, although the resulting properties of the Universe differ much from the known, present day, accepted values. The best fit model requires (with λ>0) an additional component of the physical matter density, with a negative value of the equation of state parameter, along with dust. The λ<0 solutions do not fit well with observations. Though these models do not explain the dark energy problem with consistency, their analysis does shed light on the plausibility of an alternative geometrical explanation. © 2014 American Physical Society.

Shukla P.,Indian Institute of Technology Kharagpur
International Journal of Modern Physics B | Year: 2012

The ubiquitous presence of complexity in nature makes it necessary to seek new mathematical tools which can probe physical systems beyond linear or perturbative approximations. The random matrix theory is one such tool in which the statistical behavior of a system is modeled by an ensemble of its replicas. This paper is an attempt to review the basic aspects of the theory in a simplified language, aimed at students from diverse areas of physics. © 2012 World Scientific Publishing Company.

Ray M.C.,Indian Institute of Technology Kharagpur
Journal of Applied Mechanics, Transactions ASME | Year: 2014

This paper is concerned with the derivation of the exact solutions for the static responses of the simply supported flexoelectric nanobeams subjected to the applied mechanical load and applied voltage difference across the thickness of the beams. Considering both the direct and the converse flexoelectric effects, the governing equations and the associated boundary conditions of the beams are derived to obtain the exact solutions for the displacements and the electric potential in the beams. Due to the converse flexoelectric effect, the active beams significantly counteract the applied mechanical load. The normal and the transverse shear deformations in the beams are affected by the converse flexoelectric effect in the beams resulting in the coupling of bending and stretching deformations in the beams. For the particular values of the length of the beam and the applied voltage, the deflection of the nanobeam due to the converse flexoelectric effect significantly increases with the decrease in the thickness of the beam. But the deflection of the beam remains invariant with the change in length of the beam for the particular values of the thickness of the beam and the applied voltage. Also, for the particular values of the thickness of the beam and the applied mechanical load, the induced transverse electric polarization on the surface of the beam is independent of the variation of the length of the beam and the value of the polarization increases with the decrease in the thickness of the beam. The benchmark results presented here may be useful for verifying further research and the present study suggests that the flexoelectric nanobeams may be effectively exploited for advanced applications as smart sensors and actuators at nanoscale. © 2014 by ASME.

Chandra A.,Indian Institute of Technology Kharagpur
Proceedings of the National Academy of Sciences India Section A - Physical Sciences | Year: 2012

Supercapacitors and batteries are two most important technologies which are being viewed as possible solutions for storing the energy generated using alternative sources of energy. These technologies will form an integral part of any future energy landscape and help in solving an intrinsic problem of energy sources arising due to oftenly occurring "intermittent" nature of its supply. These technologies can also address the problem of short time to long time storage needs and in protection ion of power grids from sudden spikes due to unexpected changes in supply and demand. This review deals with one of the above mentioned technologies viz., "supercapacitors". The history, development and current state of supercapacitors is also presented. Various applications ranging from automobiles to household appliances are also outlined in the review. The future of this technology is briefly discussed in the final part of the review. © The National Academy of Sciences, India 2012.

Banerjee B.,Indian Institute of Technology Kharagpur
Journal of Engineering Mechanics | Year: 2016

This article describes an inverse method for the identification of heterogeneous anisotropic elastic parameters of plate structure from an incomplete modal response. Many efforts in this area have shown that derivatives of the displacement mode shapes or curvature mode shapes are much more sensitive to the heterogeneous parameter distribution of the structure when compared with the mode shapes themselves. Thus, the curvature mode shapes are used widely to quantify the material profile. Following this observation, a strategy based on the error in constitutive equation (ECE) function, which naturally incorporates this fact seamlessly into the identification procedure, is proposed. The identification problem is posed as an optimization problem in that the cost function measures the discrepancy in the constitutive equation, which connects kinematically admissible curvature/strains and dynamically admissible couples/stresses. The resulting system becomes an extended system with primary and Lagrangian variables as the unknown with penalized measurement as the forcing function. The material update then follows by way of constitutive discrepancy, and an explicit update formula is derived. Although the regularization resulting from ill-posedness is achieved through the penalization parameter associated with the modified ECE function, this also helped to incorporate the partial and corrupted data map in the reconstruction strategy. Finally, a few numerical examples are considered to show the applicability of the proposed scheme. © 2015 American Society of Civil Engineers.

Kapat S.,Indian Institute of Technology Kharagpur
IEEE Transactions on Power Electronics | Year: 2016

Efficiency in a light load dc-dc converter is improved by reducing the switching frequency with the load current. Further, a bifrequency operation (BFO) using pulse train (PT) control can achieve spread spectrum. Using discrete-time models, this paper shows that a stable periodic BFO is generally not achievable in existing PT control methods. Thereafter, a unified multimode digital control technique is proposed, in which a voltage-mode digital pulse-width-modulator (DPWM) is used to control a predefined periodic BFO. Beside the fixed-frequency DPWM, an extra multiplexer is considered for real-time configuration to: 1) bifrequency pulse frequency modulation; 2) PT control; or 3) pulse regulation control; or 4) pulse skipping control with smooth transition. Analysis and design methods are discussed to ensure periodic BFO and to customize the power spectrum with predictable ripple parameters. A buck converter prototype is made, and the proposed control is implemented using an FPGA device. © 2015 IEEE.

Mukherjee S.,Mentor Graphics | Dasgupta P.,Indian Institute of Technology Kharagpur
International Journal of Approximate Reasoning | Year: 2013

High-level descriptions of real-time systems often use fuzzy notions of time that are left open to domain specific interpretations. In order to verify that a given implementation conforms to such loosely defined specifications, the typical approach is to verify the implementation to be correct within well defined limits of time tolerance. This approach determines whether the real-time requirements are met, but does not reflect how well it is met. Our goal in this paper is to prescribe the development of timed specifications using fuzzy notions of time, and to present a methodology for computing the quality of satisfaction of the specification on a given implementation using domain specific fuzzy membership functions. With this objective, we combine the notions of real-time interval temporal logic (like Metric Interval Temporal Logic) and fuzzy logic to derive FRTL, a fuzzy real-time temporal logic. The novelty of the proposed logic is in introducing the notion of fuzzy time intervals into the core fabric of conventional metric temporal logic. We present a method for evaluating the fuzzy truth of FRTL properties on finite traces. We discuss the motivation of computing the fuzzy truth towards evaluating the quality of control in time critical embedded control system applications. We also show that two important related problems from the domain of mixed-signal design verification, are subsumed by the proposed framework of analysis. © 2013 Elsevier Inc. All rights reserved.

Ray M.C.,Indian Institute of Technology Kharagpur
International Journal of Mechanics and Materials in Design | Year: 2010

A novel hybrid piezoelectric composite in which the microscopic piezoelectric fiber reinforcements are coated with radially aligned carbon nanotubes (CNTs) is analyzed in this study. A shear-lag model is developed to analyze the load transferred to such coated fibers from the aligned-CNT reinforced matrix in a hybrid composite application in the absence and the presence of the electric field along the length of the fiber. It is found that if the aligned CNTs are radially grown on the surface of the piezoelectric fiber then the axial load transferred to the fiber is reduced in the absence of the electric field while the axial stress in the fiber increases in the presence of the electric filed only. The radial stress in the active piezoelectric fiber significantly increases due to the radial growth of aligned CNTs on the surface of the fibers. This indicates a probable critical window for engineering the surface of the piezoelectric fiber for improving the effective piezoelectric properties. Effects of the variation of the aspect ratio of the piezoelectric fiber and the CNT volume fraction on the load transferred to such CNT-coated piezoelectric fibers are also investigated. © 2010 Springer Science+Business Media, B.V.

Ganguly S.,National Institute of Technology Rourkela | Sahoo N.C.,Petronas University of Technology | Das D.,Indian Institute of Technology Kharagpur
Fuzzy Sets and Systems | Year: 2013

This paper presents a multi-objective planning approach for electrical distribution systems under uncertainty in load demand incorporating distributed generation (DG). Both radial and meshed systems are considered. The overall influence of load demand uncertainty on planned networks is investigated in detail. Uncertainty in load demand is possibilistically modeled using a fuzzy triangular number. The two objectives in system planning are: (i) minimization of total installation and operational costs, and (ii) minimization of the risk factor. The risk factor is a function of the contingency load-loss index (CLLI), which measures load loss under contingencies, and the degree of network constraints violations. CLLI minimization improves network reliability. The network variables optimized are: (i) the network structure type (radial or meshed), (ii) the number of feeders and their routes, and (iii) the number and location of sectionalizing switches. The optimization tool is a multi-objective particle swarm optimization (MOPSO) variant that uses heuristic selection and assignment of leaders or guides for efficient identification of non-dominated solutions. The optimal number, location, and size of the DG units are determined in another planning stage. Performance comparisons between the planning approaches with possibilistic and deterministic load models highlight the relative merits and demerits. The advantages of networks obtained using the proposed planning approach in the context of DG integration are described. The proposed planning approach is validated using three typical distribution systems. © 2012 Elsevier B.V.

Sen R.,Indian Institute of Technology Kharagpur
Advances in Experimental Medicine and Biology | Year: 2010

Marine environment occupies the vast majority of the earth's surface and is a rich source of highly potent and active compounds. In recent years, microbial surfactants and emulsifiers have been reported from marine microflora. Surfactant and emulsifier molecules having diverse chemical nature such as exopolysaccharides, carbohydrate-lipid-protein complexes or glycolipopeptide, glycolipids, lipopeptides, phospholipids and ornithine lipids have been reported from various marine bacteria. These surface-active agents have been found to possess good emulsification and stabilization potentials for various lipophilic compounds such as aliphatic, aromatic and polyaromatic hydrocarbons and their uptake and degradation by the microorganisms. Few biosurfactant types such as glycolipids and lipopeptides have also been found to possess valuable biological activities. Surface-active agents from marine environments thus have tremendous potential to be used in industrial processes, for environmental remediation and as drugs. © 2010 Landes Bioscience and Springer Science+Business Media.

Das S.,University of Twente | Chakraborty S.,Indian Institute of Technology Kharagpur
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

In this paper, we demonstrate that nontrivial interactions between steric effect and electrical-double-layer (EDL) overlap phenomena may augment the effective extent of EDL overlap in narrow fluidic confinements to a significant extent by virtue of rendering the channel centerline potential tending to the ζ potential in a limiting sense as the steric effect progressively intensifies. Such a behavior may result in a virtually uniform (undiminished) magnitude of the EDL potential across the entire channel height and may cause lowering of the total charge within the EDL. © 2011 American Physical Society.

Rao K.S.,Indian Institute of Technology Kharagpur
Circuits, Systems, and Signal Processing | Year: 2012

This paper proposes a flexible method for pitch contour modification using the instants of significant excitation of the vocal tract system during the production of speech. The instants of significant excitation correspond to the instants of glottal closure (epochs) in the case of voiced speech, and to some random excitations like onset of burst in the case of nonvoiced speech. Instants of significant excitation are computed from the Linear Prediction (LP) residual of speech signals by using the property of average group-delay of minimum phase signals. The modification of pitch contour is achieved by manipulating the LP residual with the help of the knowledge of the instants of significant excitation. The modified residual is used to excite the time-varying filter, whose parameters are derived from the original speech signal. Perceptual quality of the synthesized speech is good, and is without any significant distortion. The proposed method is evaluated using waveforms, spectrograms and listening tests. Listening tests are performed on voice conversion application, where the source speaker's pitch contour is modified by the proposed method according to the target speaker's pitch contour. The performance of the proposed method is compared with Linear Prediction Pitch Synchronous Overlap and Add (LP-PSOLA) method using listening tests, for the voice conversion application. © Springer Science+Business Media, LLC 2012.

Upadhyay S.,Indian Institute of Technology Kharagpur
International Journal of Modern Physics A | Year: 2016

The structures and the associated gauge algebra of ABJM theory in = 1 superspace are reviewed. We derive the Ward identities of the theory in the class of Lorentz-type gauges at quantum level to justify the renormalizability of the model. We compute the Nielsen identities for the two-point functions of the theory with the help of enlarged BRST transformation. The identities are derived in ABJM theory to ensure the gauge independence of the physical poles of the Green's functions. © 2016 World Scientific Publishing Company.

Bhattacharya P.,Indian Institute of Technology Kharagpur
Computers and Geotechnics | Year: 2016

The pullout capacity of strip anchor plates embedded in clayey sloping ground under undrained condition has been studied by using lower bound limit analysis with finite elements. The analysis has been performed for different values of (i) slope angle (β) varying from 0° to 40° with an interval of 5°, (ii) embedment ratio (H/B) of the anchor plate varying from 3 to 7 where H is the embedment depth and B is the width of anchor plate and (iii) c/γH ranging from 0.25 to 8 in addition to the case with γ = 0. Three different orientations (θ) of the anchor plate, say horizontal (i.e. θ = 0°), parallel to the ground surface (i.e. θ = β) and vertical (i.e. θ = 90°), have been considered in the present study. For γ = 0, the pullout capacity of both vertical and horizontal plate decreases with an increase in slope angle whereas the pullout capacity of anchor plate lying parallel to the sloping ground remains unchanged for all values of β. It has been observed that the pullout capacity of the anchor plate decreases with an increase in slope angle of the ground surface for γ ≠ 0. The results are compared well with available results on pullout capacity of strip anchor plates with θ = 0° and θ = 90°. © 2016 Elsevier Ltd.

Rao K.S.,Indian Institute of Technology Kharagpur | Vuppala A.K.,LTRC
Speech Communication | Year: 2013

In this paper, a non-uniform time scale modification (TSM) method is proposed for increasing or decreasing speech rate. The proposed method modifies the durations of vowel and pause segments by different modification factors. Vowel segments are modified by factors based on their identities, and pause segments by uniform factors based on the desired speaking rate. Consonant and transition (consonant-to-vowel) segments are not modified in the proposed TSM. These modification factors are derived from the analysis of slow and fast speech collected from professional radio artists. In the proposed TSM method, vowel onset points (VOPs) are used to mark the consonant, transition and vowel regions, and instants of significant excitation (ISE) are used to perform TSM as required. The VOPs indicate the instants at which the onsets of vowels take place. The ISE, also known as epochs, indicate the instants of glottal closure during voiced speech, and some random excitations such as burst onset during non-voiced speech. In this work, VOPs are determined using multiple sources of evidence from excitation source, spectral peaks, modulation spectrum and uniformity in epoch intervals. The ISEs are determined using a zero-frequency filter method. The performance of the proposed non-uniform TSM scheme is compared with uniform and existing non-uniform TSM schemes using epoch and time domain pitch synchronous overlap and add (TD-PSOLA) methods. © 2013 Elsevier B.V. All rights reserved.

Manna B.,National Institute of Technology Rourkela | Baidya D.K.,Indian Institute of Technology Kharagpur
Soil Dynamics and Earthquake Engineering | Year: 2010

The influence of nonlinearity on the dynamic response of cast-in-situ reinforced concrete piles subjected to strong vertical excitation was studied. Forced vibration test of single piles (L/d=10, 15, 20) and 2×2 pile groups (s/d=2, 3, 4 for each L/d) were conducted in the field for two different embedded conditions of pile cap. From the measured nonlinear response curves, the effective pile-soil system mass, stiffness and damping were determined and the nonlinear response curves were back-calculated using the theory of nonlinear vibration. The test results were compared with the continuum approach of Novak with dynamic interaction factor approach using both linear and linear-equivalent numerical methods. Reasonable match between the measured and predicted response was found for linear-equivalent methods by introducing a weak boundary-zone around the pile to approximately account for the nonlinear behaviour of pile-soil system. The test data were used to establish the empirical relationship in order to estimate the extent of soil separation around the pile with soil under vertical vibration. © 2010 Elsevier Ltd. All rights reserved.

Bhowmik S.K.,Indian Institute of Technology Kharagpur | Bernhardt H.-J.,Ruhr University Bochum | Dasgupta S.,Indian Institute of Science
Precambrian Research | Year: 2010

In this study, we deduce the age of the collisional orogeny in the Aravalli-Delhi Mobile Belt, using electron microprobe (EMP) dating of monazites of two suites of metapelitic to metapsammitic rocks from the Banded Gneissic Complex of Central Rajasthan. These metasediments of the Sandmata and the Mangalwar Complexes record a high-pressure, upper amphibolite (P ∼ 10.3 ± 0.8 kbar, T ∼ 675 ± 60 °C) to granulite facies (P ∼ 12-14 kbar, T ∼ 815 °C) peak metamorphism (M2P stage) and a post-peak decompression to ∼5 kbar, 575-660 °C (M2R stage), following a clockwise P-T path (M2 event). The metapelites of the Sandmata Complex, however, record an older, medium-pressure, sillimanite-facies granulite metamorphism (M1 event). Electron microprobe dating of monazites, occurring in the different textural settings of three metapelite granulite samples of the Sandmata Complex yields three mean spot age populations at ∼1700 ± 3 to ∼1733 ± 15 Ma, ∼1597 ± 6 to ∼1629 ± 23 Ma and ∼882 ± 15 Ma. While Late Palaeoproterozoic age populations are correlated with the timing of the M1 metamorphism, the Early Neoproterozoic ages from garnet-breakdown textural domain constrain the timing of the overprinting M2R event. Interpretation of the Late Mesoproterozoic age component is problematic. It may reflect either a mixed age due to partial Pb loss of the Palaeoproterozoic monazites by a younger high-grade event or may define the timing of a high-grade tectonothermal event, the imprints of which have been registered in the Proterozoic mobile belts of central, eastern, north-eastern and south-eastern India. Monazites from the metapelites of the Mangalwar Complex yield characteristic Late Mesoproterozoic to Neoproterozoic ages with clusters at 946 ± 6, 909 ± 9 and 865 ± 10 Ma. The metagranites intrusive into the M1 granulites additionally register an emplacement age of ∼978 ± 18 Ma. The age span of ∼0.98-0.95 to ∼0.88-087 Ga is taken as the age of the M2 event. Based on these geochronologic and metamorphic findings, we assign a Grenvillian age for the collisional orogeny in the Aravalli-Delhi Mobile Belt. The extent of propagation of the Grenvillian orogenic front in the Aravalli-Delhi orogen and its implication in Rodinia reconstruction are also discussed. © 2010 Elsevier B.V. All rights reserved.

Mamtani M.A.,Indian Institute of Technology Kharagpur
Journal of the Geological Society of India | Year: 2010

The area-perimeter fractal dimension (D) of quartz grains has earlier been proposed as a strain-rate gauge based on experimental deformation of quartz aggregates. To test the application in naturally deformed, rocks, D is calculated in (a) three quartzitos belonging to the Lunavada Group of rocks (Aravalli Mountain Belt, NW India) that developed textures between 420-600°C and (b) one quartz reef sample from the Malanjkhand Granite (Central India), which underwent dynamic recrystallization between 250-400°C Using the above T ranges and calculated D values, strain-rates are calculated for the two sets of samples. A 10-12,7 s-1 strain rate at 250°C is calculated for the quartz reef sample. However, at higher temperatures the calculated strain-rate is >10-10 s-1 for the quartz reef and the quartzite samples. The quartzites show evidence of dynamic recrystallization by grain boundary migration (GBM) and subgrain rotation (SGR), while the quartz reef is replete with evidence of bulging (BLG) recrystallization. T and calculated strainrates are plotted on available recrystallization map of quartz. It is demonstrated that whilst the T/strain-rate of the quartzites does not fall in the region of GBM and SGR, the T/strain-rate of the quartz reef falls in the BLG region. The problems with strain-rate calculations using area perimeter fractal dimension are discussed. It is concluded that the method of strain-rate calculation can be used only for lower T. © GEOL. SOC. INDIA.

Maity R.,Indian Institute of Technology Kharagpur | Kashid S.S.,Indian Institute of Technology Bombay
Journal of Hydrometeorology | Year: 2010

This paper investigates the use of large-scale circulation patterns (El Niño-Southern Oscillation and the equatorial Indian Ocean Oscillation), local outgoing longwave radiation (OLR), and previous streamflow information for short-term (weekly) basin-scale streamflow forecasting. To model the complex relationship between these inputs and basin-scale streamflow, an artificial intelligence approach-genetic programming (GP)-has been employed. Research findings of this study indicate that the use of large-scale atmospheric circulation information and streamflow at previous time steps, along with OLR as a local meteorological input, potentially improves the performance of weekly basin-scale streamflow prediction. The genetic programming approach is found to capture the complex relationship between the weekly streamflow and various inputs. Different input variable combinations were explored to come up with the best one. The observed and predicted streamflows were found to correspond well with each other with a coefficient of determination of 0.653 (correlation coefficient r = 0.808), which may appear attractive for such a complex system. © 2010 American Meteorological Society.

Majumder A.K.,Indian Institute of Technology Kharagpur
International Journal of Mineral Processing | Year: 2010

In an effort to test the extent to which fundamental fluid mechanics can provide a prediction of particle separation in a flowing film concentrator, a study on a simple parallel-sided channel has been carried out using glass beads at various particle concentrations and flow rates. The actual particle separation taking place was compared to predictions made by first describing the slurry flow based on the Prandtl's mixing length approach. Particle concentration distributions were described using Hunt's sediment transport model. Settling velocities of particles in water were calculated using either the Richardson and Zaki or Brauer and Thiele models. The latter takes into account particle size and density distributions and solids volumetric concentration. The resulting predictions of particle separation are remarkably good. © 2010 Elsevier B.V. All rights reserved.

Mukherjee J.,Indian Institute of Technology Kharagpur
Pattern Recognition Letters | Year: 2013

In the past, different distance functions and their combinations had been proposed as good approximators of Euclidean metrics. In particular in recent years, a few distance functions with their general forms in n-dimensional real and integer spaces were identified for their improved performances in approximating corresponding Euclidean metrics. In this paper, we have identified a linear combination of two such distance functions from the families of weighted distances (WD) and weighted t-cost distances (WtD), which provides significant improvement over the past results in the quality of approximation. Further, we discuss a special case of linear combination, convex combination of distances, and provide optimal combinations by minimizing mean square error (MSE). In this case also the proposed pair of norms perform superior to other reported combinations. In our study, we also present new results related to characterization of overestimated and underestimated norms of Euclidean norm by their hyperspheres. The analysis leads to new results on theoretical bounds of maximum relative error (MRE) of some of the existing distance functions, including their linear combinations. © 2013 Elsevier B.V. All rights reserved.

Samanta P.K.,Ghatal Rabindra Satabarsiki Mahavidyalaya | Chaudhuri P.R.,Indian Institute of Technology Kharagpur
Materials Letters | Year: 2012

A wet chemical method has been used to grow rarely observed ZnO octahedrons at room temperature without using any surfactant. The X-ray diffraction data confirmed the formation of hexagonal phase of ZnO. The size variation of the octahedrons indicates that the growth unit is not arbitrary but octahedron one. Formation of the octahedral nanostructures depends on the precursor concentrations, growth kinetics, growth temperature and duration of the chemical growth process. This type of octahedral structure occurs due to the electrostatic interaction between different basal polar planes of ZnO. The absorption spectrum studies revealed the band gap enhancement due to quantum size effect. The fabricated ZnO octahedron shows strong violet emission due to recombination of electron at Zn-interstitial and hole in the valence band. © 2011 Elsevier B.V. All rights reserved.

Nayak J.,Indian Institute of Technology Kharagpur
Materials Chemistry and Physics | Year: 2012

Cadmium sulfide-zinc oxide composite nanorods having at least 100 nm diameters were synthesized by a two-step chemical deposition technique. Polycrystalline nanorods of ZnO were grown on indium tin oxide coated quartz substrate by aqueous chemical growth technique. Cadmium sulfide was deposited on the surface of the ZnO nanorod thin film by chemical bath deposition. The X-ray diffraction results revealed the co-existence of polycrystalline CdS and ZnO, both having hexagonal structures. Neither any phase mixing nor any surface diffusion induced alloying was observed. Micro-Raman study detected a pair of optical phonons at 301 cm -1 and 438 cm -1 corresponding to hexagonal CdS and ZnO, respectively. An enhanced light to electricity conversion efficiency of 2.52% was recorded from CdS-ZnO photoanode based electrochemical solar cell under 0.5 sun illumination condition (50 mW cm -2). We observed a significant enhancement of short circuit current of the electrochemical solar cells due to addition of ionic salt solution to the electrolyte. © 2012 Elsevier B.V.

Jha J.K.,Indian Institute of Technology Kharagpur | Shanker K.,Indian Institute of Technology Kanpur
International Journal of Production Research | Year: 2013

This study considers a two-echelon system in which a vendor produces a product at a finite production rate and supplies it to several buyers facing independent normally-distributed demands. The product is delivered to the buyers using a set of different speed vehicles with identical capacity and different operating costs. The issues of lead time reduction and the service level constraint on the buyers have been incorporated in the model. A model is formulated to determine the optimal production-inventory policy, vehicle routes and vehicle type for each route by minimising the related production, inventory, lead time crashing and transportation costs of the system while satisfying the service level constraint on each buyer. A coordinated two-phase iterative approach is proposed to solve the model. Finally, a numerical example is included to describe the solution approach and illustrate the results. © 2013 Taylor & Francis.

Sahoo M.P.K.,Indian Institute of Technology Kharagpur | Choudhary R.N.P.,Institute of Physics, Bhubaneswar
Materials Letters | Year: 2012

A solid-solution of PbMg1/3Nb2/3O3- BiFeO3 (60:40) was prepared by a high-temperature solid-state reaction technique. Rietveld structural analysis using high-resolution X-ray diffraction data/pattern of the above system unfolds a rhombohedral crystal structure with R3m space group. Detailed studies of dielectric properties of the material in wide temperature range (30-420 °C) exhibit a dielectric anomaly at 300 °C which may be related to the magnetic transition. Increase in relative permittivity above this transition temperature is supported by thermally activated transport of oxygen vacancies and hopping of electrons. The temperature response of ac conductivity in this material is found to be governed by the motion of ionized oxygen vacancies, polarons and lead (Pb) vacancies. © 2011 Elsevier B.V. All rights reserved.

Sengupta A.,Indian Institute of Technology Kharagpur
Geotechnical and Geological Engineering | Year: 2012

The case history of a failure of a RE wall has been presented. The wall failed immediately upon completion due to the overestimation of the strengths of the foundation clay layers and due to the underestimation of the self weight of the fill materials. A typical cross-section of the wall along with the stabilizing embankment and the foundation are modeled numerically by the limit equilibrium method and by a finite element method. The strengths of the foundation soils are determined by field tests done after the failure of the wall. Both the analyses predicted failure of the wall. The deformations predicted by the finite element method are found to be comparable to the observed field data. The numerical analyses further indicate that by consolidating a foundation clay layer to a minimum undrained strength of 45 kPa, the required factor of safety for the wall along with the road embankment can be achieved theoretically. Accordingly, prefabricated vertical drains are used to expedite the drainage and consolidation of the foundation clay layers. After the field tests confirm that the required minimum undrained strength is achieved, the RE wall and the embankment have been rebuilt successfully and now in full operation. © 2012 Springer Science+Business Media B.V.

Padmanabhan V.,Indian Institute of Technology Kharagpur
Journal of Chemical Physics | Year: 2012

Nanoparticles in polymer films have shown the tendency to migrate to the substrate due to an entropic-based attractive depletion interaction between the particles and the substrate. It is also known that polymer-grafted nanoparticles show better dispersion in a polymer matrix. Here, molecular dynamics simulations are employed to study the effect of grafting on the nanoparticle segregation to the substrate. The nanoparticles were modeled as spheres and the polymers as bead-spring chains. The polymers of the grafts and the matrix are identical in nature. For a purely repulsive system, the nanoparticle density near the surface was found to decrease as the length of grafted chains and the number of grafts increased and in the bulk, the nanoparticles are well-dispersed. Whereas, in case of attractive systems with interparticle interactions on the order of thermal energy, the nanoparticles segregated to the substrate even more strongly, essentially forming clusters on the wall and in the bulk. However, due to the presence of grafted chains on the nanoparticles, the clusters formed in the bulk are structurally anisotropic. The effect of grafts on nanoparticle segregation to the surface was found to be qualitatively similar to the purely repulsive case. © 2012 American Institute of Physics.

Mukherjee R.,Indian Institute of Technology Kharagpur
BioMed Research International | Year: 2014

Deficient trophoblast invasion and anomalies in placental development generally lead to preeclampsia (PE) but the inter-relationship between placental function and morphology in PE still remains unknown. The aim of this study was to evaluate the morphometric features of placental villi and capillaries in preeclamptic and normal placentae. The study included light microscopic images of placental tissue sections of 40 preeclamptic and 35 normotensive pregnant women. Preprocessing and segmentation of these images were performed to characterize the villi and capillaries. Fisher's linear discriminant analysis (FLDA), hierarchical cluster analysis (HCA), and principal component analysis (PCA) were applied to identify the most significant placental (morphometric) features from microscopic images. A total of 10 morphometric features were extracted, of which the villous parameters were significantly altered in PE. FLDA identified 5 highly significant morphometric features (>90% overall discrimination accuracy). Two large subclusters were clearly visible in HCA based dendrogram. PCA returned three most significant principal components cumulatively explaining 98.4% of the total variance based on these 5 significant features. Hence, quantitative microscopic evaluation revealed that placental morphometry plays an important role in characterizing PE, where the villous is the major component that is affected. © 2014 Rashmi Mukherjee.

Maiti J.,Indian Institute of Technology Kharagpur
Quality and Reliability Engineering International | Year: 2013

Although various multivariate process monitoring techniques have been developed, they do not diagnose the process for finding the root causes of irregularities during production. There have been recent studies on a new method that involves process-oriented basis representation, which links the process variation to its causes, and thus helps in monitoring and diagnosing a process. However, all the studies done so far focused on its application. In this paper, a method is proposed to build the process-oriented basis for a process irrespective of the number of variables characterizing it. Along with various other statistical techniques, factor analysis and cluster analysis, with customized distance function, are used in developing the method. The built in process-oriented basis is further used for multivariate statistical process control and process capability analysis. Multivariate solder-paste problem from electronics industry is used for illustration. Copyright © 2012 John Wiley & Sons, Ltd.

Khan M.M.,Yeungnam University | Ansari S.A.,Yeungnam University | Pradhan D.,Indian Institute of Technology Kharagpur | Ansari M.O.,Yeungnam University | And 3 more authors.
Journal of Materials Chemistry A | Year: 2014

Visible light-active TiO2 (m-TiO2) nanoparticles were obtained by an electron beam treatment of commercial TiO2 (p-TiO2) nanoparticles. The m-TiO2 nanoparticles exhibited a distinct red-shift in the UV-visible absorption spectrum and a much narrower band gap (2.85 eV) due to defects as confirmed by diffuse reflectance spectroscopy (DRS), photoluminescence (PL), X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and linear scan voltammetry (LSV). The XPS revealed changes in the surface states, composition, Ti4+ to Ti3+ ratio, and oxygen deficiencies in the m-TiO2. The valence band XPS, DRS and PL results were carefully examined to understand the band gap reduction of m-TiO 2. The visible light-responsive enhanced photocatalytic activity of m-TiO2 was demonstrated by degrading methylene blue and brilliant blue G. The EIS and LSV in the dark and under visible light irradiation further support the visible light-induced photocatalytic activities of the m-TiO 2 due to a decrease in electron transfer resistance and an increase in photocurrent. This study confirms that m-TiO2 can be used effectively as a photocatalyst and photoelectrode material owing to its enhanced visible light-induced photocatalytic activity. © 2014 The Royal Society of Chemistry.

Sengupta J.,Manipal University India | Sahoo R.K.,Indian Institute of Technology Kharagpur | Mukherjee C.D.,Saha Institute of Nuclear Physics
Materials Letters | Year: 2012

A comparative study of the physical properties of undoped Zinc Oxide (ZnO) and Al doped Zinc Oxide (AZO) thin films were performed as a function of annealing temperature. The structural properties were analyzed using X-ray diffraction and the recorded patterns indicated that the crystallinity of the films always enhanced with increasing annealing temperature while it degrades with Al doping. The topographical modification of the films due to heat treatment was examined by atomic force microscopy which revealed that annealing roughened the surface of all the films; however the AZO films always exhibited smoother morphology than ZnO. Study of the optical properties by UV-Visible spectrophotometer demonstrated that the transmittance was gradually diminished with the rise in annealing temperature. In addition, a notable increase in the optical band gap was also observed for the AZO films. © 2012 Elsevier B.V. All rights reserved.

Chakraborti N.,Indian Institute of Technology Kharagpur
Surface Engineering | Year: 2014

Two algorithms, evolutionary neural net (EvoNN) and biobjective genetic programming (BioGP), were developed and tested on a problem aimed at designing a strong and durable zinc coating over iron. The novel idea was to develop a coating that would fail with the minimum amount of strain, after a maximum amount of energy absorption. In a molecular dynamics (MD) environment, where empirical interatomic potentials were considered and the trajectory of an ensemble of atoms was computed through numerical integration of Newton's equation of motion, the known phases in the zinc coated iron were generated and equilibrated. The cumulative energy absorption was recorded from the initiation of the shear force until the failure, and the strain at the failure point was calculated. To circumvent this problem, the option is to conduct a limited number of methodically designed simulations and to construct meta models for both strain and energy from that data using EvoNN or BioGP software. It was found that majority of the best ranked optimum solutions were obtained for the interface, rendering the top layer of the coating strongest among all.

Kumar M.,Napier University | Antony J.,University of Strathclyde | Tiwari M.K.,Indian Institute of Technology Kharagpur
International Journal of Production Research | Year: 2011

Although Six Sigma has been in business lexicon for more than 20 years, research has shown the need of practical implementation framework for successful deployment of Six Sigma, especially in the context of small and medium-sized enterprises (SMEs). This article proposes a Six Sigma implementation framework customised to the needs of SMEs by performing a critique of quality management frameworks/models for SMEs and drawing conclusion from the empirical research conducted over 3 years. If Six Sigma is poorly launched, it will be very difficult to reorganise and regain momentum. Though the framework was tested in three SMEs and revised, still its robustness needs to be checked and refined based on suggestions and comments from industry, practitioners and academics. © 2011 Taylor & Francis.

Routray W.,McGill University | Mishra H.N.,Indian Institute of Technology Kharagpur
Comprehensive Reviews in Food Science and Food Safety | Year: 2011

Yogurt is a basic dairy product that has been consumed for centuries as a part of the diet, even when its beneficial effects were neither fully known nor scientifically proven. With time, yogurt has been continuously modified to obtain a product with better appeal and nutritional effects. The flavor components of yogurt are affected because of these modifications. The present review article is focused on the influence of the different parameters and modifications on aroma and taste components of yogurt. Extensive work has been done to explore the effect of chemical components as well as the microbial, processing, and storage aspects. The popularity of yogurt as a food component depends mainly on its sensory characteristics, of which aroma and taste are most important. This review also outlines the effects of the different modifications attempted in the composition of yogurt. © 2011 Institute of Food Technologists®.

Meher S.K.,Satyam Computers Ltd. | Pradhan A.K.,Indian Institute of Technology Kharagpur
Electric Power Systems Research | Year: 2010

The present paper proposes the design of a tool to quantify power quality (PQ) parameters using wavelets and fuzzy sets theory. The tool merges the best characteristics of these two theories in establishing a method to analyze PQ events. The proposed method addresses two issues, such as selection of discriminative features and classifies event classes with minimum error. Wavelet features (WF) of PQ events are extracted using wavelet transform (WT) and fuzzy classifiers classify events using these features. Often the captured signals are corrupted by noise. Also the non-linear and non-stationary behavior of PQ events make the detection and classification tasks more cumbersome. WT has been proven an effective tool for detecting and classifying these. We exploited WT for noise removal to make the task of detection and/or localization of events simpler. In the proposed approach of event classification, fuzzy product aggregation reasoning rule based method has been used. Varieties of PQ events including voltage sag, swell, momentary interruption, notch, oscillatory transient and spikes are considered for performance analysis. Comparative simulation studies revealed the superiority of proposed method compared to WF based fuzzy explicit, fuzzy k-nearest neighbor and fuzzy maxim