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Tarafdar A.,IIT ISM | Sinha A.,IIT ISM
Environmental Science and Pollution Research | Year: 2017

The role of preferential biodegradation in the reduction of cancer risk caused by polycyclic aromatic hydrocarbons (PAHs) has been studied. A consortium of microorganisms isolated from aged oil refinery exposed soil was used to degrade 13 PAHs content extracted from an urban traffic site soil. The biodegradation arranged in a batch process with a mineral salt broth, where PAHs were the sole carbon source. 70.46% biodegradation of the total PAHs occurred in an incubation period of 25 days. Sequential or preferential biodegradation took place as the lower molecular weight (LMW) PAHs were more prone to biodegradation than that of the higher molecular weight (HMW) PAHs. Microorganisms from the isolated consortia preferred the simpler carbon sources first. The relatively higher carcinogenicity of the HMW PAHs than that of the LMW PAHs leads to only 40.26% decrement in cancer risk. Initial cancer risk for children was 1.60E−05, which was decreased to 9.47E−06, whereas, for the adults, the risk decreased to 1.01E−05 from an initial value of 1.71E−05. The relative skin adherence factor for soil (AF) turned out to be the most influential parameter with 54.2% contributions to variance in total cancer risk followed by the exposure duration (ED) for children. For the adults, most contributions to the variance in total cancer risk were 58.5% by ED and followed by AF. © 2017 Springer-Verlag Berlin Heidelberg

Ranjan R.,IIT ISM
Advances in Intelligent Systems and Computing | Year: 2017

Secure routing (SR) is one of the most important issues in Mobile Ad hoc Networks (MANETs). Recently, in 2013, Zhao et al. proposed an efficient routing integrated framework for MANETs. They claimed that their proposed scheme distributes the system parameter only to the authenticate nodes before network set up phase. However, based on cryptanalysis, we have found that an unauthenticated nodes are also be able to get that original system parameter and behave like a malicious node in the network. Thus, their scheme fails to provide an authenticate distribution mechanism in real life application. As a counter measurement, this paper aims to present an efficient authenticated distribution mechanism that can be incorporated very efficiently in their scheme. Our proposed technique is found to be secure under the hardness of Computational Diffie-Hellman (CDH) assumption. © Springer Nature Singapore Pte Ltd. 2017.

The present paper is concerned with the study of propagation of torsional surface waves in a non-homogeneous crustal layer under initial stress overlying a viscoelastic half-space. In the layer directional rigidities and density are considered to vary quadratically with depth. The dispersion equation is derived in closed form by means of separation of variables. As a special case when the layer is homogeneous, the dispersion relation coincides with the classical torsional wave equation. To show the nature of torsional waves, dispersion curves have been plotted by taking variation in initial stress, inhomogeneity and viscoelastic parameters. The substantial influence of initial stress, heterogeneity and viscoelastic parameter on the phase velocity are elucidated by means of graphs. This problem may find its applications in the field of earthquake engineering and geophysical prospects. © 2017 The Authors.

Upreti K.K.,IIT ISM | Bag S.,IIT ISM
Proceedings of International Conference on Frontiers in Handwriting Recognition, ICFHR | Year: 2017

Segmentation of unconstrained handwritten words into characters in an optically scanned document image data is an essential task and presents challenges to researchers with a wide variety of handwritings, large varieties of pen-types, poor image quality, and a lack of ordering information of strokes. This paper contributes methods for accurate full segmentation of Hindi word images into constituent characters and modifiers. It follows the polygonal approximation approach for the segmentation, and makes use of structural properties along with directional measures to determine segmentation points in Hindi word images. The main methodological contribution of this paper is the use of polygonal approximation technique for word segmentation which is based on certain structural properties of Hindi language. Second focus of this work lies on the fact that segmentation is done without removal of shirorekha which eliminates the complexities present in earlier works. Experiments on real-world data show that our novel method is always competitive and results in more top performances than any of the other measures. © 2016 IEEE.

Coalbed methane (CBM) reservoirs contain gas molecules in adsorbed state into the solid matrix of coal. The pressure depletion in CBM reservoir causes the matrix gas to desorb into the cleat system which leads to matrix shrinkage. The pore volume of the cleat network changes as coal matrix shrinks. Consequently, cleat porosity and permeability of reservoir change as reservoir pressure depletes. The change in cleat porosity and permeability due to shrinkage of coal matrix with depletion of reservoir pressure invalidates the underlying assumptions made in the derivation of diffusivity equation. Under the conditions of changing porosity and permeability, the utility of the standard method of inflow performance relationship (IPR), paired with (Formula presented.) method suggested by King (in: SPE Annual Technical Conference and Exhibition, New Orleans, 1990), for performance prediction diminishes. In this paper, an effort has been made to predict reservoir performance of such CBM reservoirs with an alternative approach. The method suggested by Upadhyay and Laik (Transp Porous Media, 2017. doi:10.1007/s11242-016-0816-6) has been leveraged to describe pseudo-steady-state flow in the form of a new equation that relates stress-dependent pseudo-pressure function with time. The analytical equation derived in this paper is useful in predicting reservoir pressure and flowing bottom hole pressure of a CBM well under the situation when coal matrix shrinks below desorption pressure. The paper aims to predict production performance of CBM reservoirs producing under the influence of matrix shrinkage effect with an approach alternative to conventional IPR approach paired with (Formula presented.) method. The results of this analytical solution have been validated with the help of numerical simulator CMG–GEM as well as in-field production data. The equations and workflow suggested in this paper can be easily implemented in spreadsheet applications like Microsoft Excel tools. © 2017 Springer Science+Business Media B.V.

This paper presents an outcome of the broader effect to assess the importance of magnetoelasticity, compressive and tensile initial stress in soil dynamics. Haskell’s matrix technique is employed to investigate the SH-wave propagation in a multilayered magnetoelastic orthotropic (MMO) medium. The dispersion relation for the total ((Formula presented.)) layers lying over a half-space is obtained in a closed form. Special cases are derived for both the single and double layers, and the obtained relations are found to be in good agreement with the Classical Love wave equation. Based on the finite difference technique, a stability analysis is performed to reduce the escalation of errors to make it stable and convergent. The expression for the phase and group velocities is attained by this technique when the SH-wave propagates across the MMO medium. Numerical computations and graphical exhibition have been carried out to show the effects of different values of the magnetoelastic coupling parameter, compressive and tensile initial stresses and courant number on the phase and group velocities. © 2017 Springer-Verlag Wien

Parida S.K.,National Institute of Technology Agartala | Sahu S.,IIT ISM
Chemical Physics Letters | Year: 2017

We present our calculations based on density functional theory (DFT) to investigate the chemical reactivity of CO on second-row dicarbides, C2X with X = Na-Cl. Condensed Fukui function analyses infer the carbon atom of C2X to be the most active site for CO interaction and the fact is also supported by Mulliken charge analysis and comparatively lesser average local ionization energy for the active carbon atom. The nature of interaction has been studied using Bader's topological analysis, and large electron density at the bond critical point (BCP) (ρ > 0.30 a.u. with negative ∇2ρ) between C of C2X and C of CO indicates the C–C bonding to be shared-kind. © 2017 Elsevier B.V.

An experimental investigation has been carried out to study flow and heat transfer in solar air heater for inline holes inserted between absorber and back plate. The analysis has been carried out for cross flow conditions. The effect of flow and geometrical parameters, especially jet diameter and hydraulic diameter has been studied. Mass flow rate for the study is varied corresponding to the Reynolds number range of 4600–12,000. The jet diameter, streamwise pitch, and spanwise pitch, each normalized by hydraulic diameter, i.e. Dj/Dh, X/Dh, and Y/Dh, are in the range: 0.053–0.084, 0.53–0.63, and 0.53–0.63 respectively. Performance is studied in terms of Temperature Rise Parameter (TRP), collector efficiency, and Nusselt number. Hourly variations of solar intensity have also been shown. Collector efficiency increases and Temperature Rise Parameter decreases with increase in mass flow rate for all geometrical configurations. All the above-listed performance parameters are found to be maximum at jet diameter to hydraulic diameter ratio of 0.07. A correlation for Nusselt number in terms of Reynolds number, jet diameter, and hydraulic diameter has also been developed. © 2017 Elsevier Ltd

Mathan Kumar N.,IIT ISM | Senthil Kumaran S.,RVS Educational Trusts Group of Institutions | Kumaraswamidhas L.A.,IIT ISM
Journal of Alloys and Compounds | Year: 2016

In this study, the Al 2618 aluminium alloy is reinforced with Si3N4 (Silicon Nitride), AlN (Aluminium Nitride) & ZrB2 (Zirconium Boride) in wt. % of (0,2,4,6,8) by stir casting process. The tribological and mechanical properties of these composites particles were investigated under dry sliding conditions. The mechanical properties of the composites is studied by conducting various test like hardness test, tensile test and compression test to understand the relationship between the wt. % of reinforcement and the matrix metal. This is followed by the micro structural study to examine the bond formation and effect of grain size reduction due to the addition of reinforcement. The Taguchi L25 orthogonal array is used to optimize the process parameters to obtain minimum wear rate and the analysis of variance (ANOVA) was used to investigate the influence of parameter affecting the wear rate. The Scanning Electron Microscope (SEM) analysis is carried out to understand the wear mechanism of worn out surfaces and the wear debris. The manipulate of the wt. % of reinforcements and applied load on the wear rate, wear resistance, specific wear rate, coefficient of wear rate and the mass loss were premeditated using the pin-on-disk method. © 2016 Elsevier B.V.

The objective of the present study is to estimate hydraulic load, induced stress and factor of safety of the Savonius hydrokinetic turbine when operating under free stream velocity of 0.3 m/s to 4 m/s at rotor angle 0° to 360°. Hydraulic load evaluated from CFD analysis, whereas the induced stress computed from FEM analysis based on the computed hydraulic load through CFD in ANSYS 14. The effects of deflector and duct augmentation technique on the hydraulic load and induced stress have also been investigated. The maximum hydraulic load and von-Mises stress on rotor are found as 0.57 Mpa and 153.41 Mpa respectively in case of duct with single deflector augmentation techniques at rotor angle 0°, 180° and 360° at 4 m/s free stream velocity. In Savonius rotor with augmentation techniques, at higher free stream velocity the factor of safety reached very low, somewhat equal or less than minimum specified limit of failure. Computation results show that front area of shaft rotor from inlet side experiences zone of high von-Mises stress and has minimum factor of safety that leads to chances of fatigue crack, when applied for a free stream velocity greater than 2 m/s. © 2016 Elsevier Ltd

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