National Institute of Technology, Patna

www.nitp.ac.in
Patna, India

The National Institute of Technology Patna , formerly Bihar School of Engineering and Bihar College of Engineering, is a public engineering institution located in Patna in the Indian state of Bihar. It was renamed to NIT Patna, by the Government of India on January 28, 2004. It is an autonomous institute functions directly under Ministry of Human Resource Development, Government of India. Wikipedia.

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Bhattacharya S.,National Institute of Technology, Patna
1st IEEE International Conference on Power Electronics, Intelligent Control and Energy Systems, ICPEICES 2016 | Year: 2016

Power Systems are inherently non-linear systems that are frequently subjected to various disturbances causing oscillations at low frequencies that may lead to instability. Generators are usually provided with power system stabilizers minimize the effect of these oscillations. The objective of this paper is find the optimal parameters for a conventional 'lead-lag compensator based Power System Stabilizer (PSS)' for a system comprising of a 'generator connected to an infinite bus' and containing a ST1A type excitation system. The tuning of the parameters of the 'Power System Stabilizer' is accomplished using the 'Particle Swarm Optimization (PSO)' algorithm. In this paper, a Fuzzy Power System Stabilizer (FPSS) where the optimal values of the parameters of the FPSS are decided using the PSO algorithm is also designed. The Particle Swarm Optimization based conventional PSS and the 'Particle Swarm Optimization based Fuzzy PSS' are also incorporated in a system containing multiple machines to check the system responses under different loading conditions and faults of different types. The simulation results clearly prove the efficiency of the PSO based conventional and fuzzy power system stabilizers in damping the low frequency speed and power oscillations occurring in the power system due to various disturbances. © 2016 IEEE.


Sharma B.K.,National Institute of Technology, Patna
Midwest Symposium on Circuits and Systems | Year: 2017

Sustained scaling for TerraHertz SiGe HBT has led to transit frequency = 315GHz at 300K but it has simultaneously degraded BVCEO to 1.63V.This has placed a high premium on UHF analog circuit design A theoretical formalism of the variable latching phenomena of CE BJT under various drive conditions, discovered by the Author in 1989, is one of the central problems in the design of high speed circuits. None of the industrial standards namely VBIC, HICUM and MEXTERM have been able to capture this feature.This paper takes a circuit plus device approach to develop a single analytic relation to model the variable latching phenomena of CE BJT current sources. This analytic relationship has been verified by experimental results using 2N3055 CE current sources with 90 percent confidence level. Proposed analytic relationship embedded in the compact model of HSPICE will enable exceptional model-To-hardware correlation in simulations of the variable latching phenomena and thereby lead to considerable improvement in concept-Todesign-To-industrial production. This in turn will vastly change the scale of economy of IC chips production. This study has also established tentatively that Universal Hybrid-pi model is the correct small signal model of CE BJT which has been reported in JSSC-July-16-0310. © 2016 IEEE.


Sinha A.K.,National Institute of Technology, Patna | Singh S.,National Institute of Technology, Patna
International Journal of Civil Engineering and Technology | Year: 2017

Frequent earthquakes round the globe and large no of structures vulnerable to it have necessitated the need for structural response control to gain pace in application around the globe. This paper discusses the use and effectiveness of one such device, fluid viscous dampers, for response control of structures and to reduce damping demand on structural system. In this paper a non-linear time history analysis has been carried out on a 3D model of a 12 story RCC MRF building using 3-directional synthetic accelerogram. Two different cases of building models with and without supplemental damping have been analyzed using ETABS. The story responses in terms of absolute maximum displacement and story drift have been compared. Time history response plots for the two models have also been compared for various responses viz. roof displacement and acceleration, base shear and story shear forces, along with the various energy components and damping behavior. The results of the time history analysis are in close conformation with previous investigations and represent the effectiveness of dampers in improving the structural response as well as damping demand on structural systems. © IAEME Publication.


Sahay A.,National Institute of Technology, Patna
Physical Review D | Year: 2017

Thermodynamic fluctuation metrics in Ruppeiner's formalism are worked out for Kerr-AdS black holes in the extended state space. The implications of constraints upon the state space geometry and their correspondence with thermodynamical ensembles are explicitly worked out in the most general setting. The state space scalar curvature for a given ensemble is found to be sensitive to the instabilities or phase transitions therein. In particular, it is found that the appropriate Ruppeiner scalar curvature does encode critical phenomena in the Kerr-AdS black holes. A detailed study is undertaken of the curvature contour of the state space of the 4D Kerr-AdS black hole, and suitable inferences are drawn. In particular, thermodynamic geometry suggests an instability in the Schwarzschild-AdS limit for all the ensembles except the pressure ensemble, which is equivalent to the unextended state space of the Kerr-AdS black holes. The extrinsic geometry of the ensemble hypersurfaces is introduced, and its relevance to constrained thermodynamic fluctuations is discussed. A new interpretation for the thermodynamic curvature of black hole systems is suggested. © 2017 American Physical Society.


Sinha A.K.,National Institute of Technology, Patna
International Journal of Civil Engineering and Technology | Year: 2017

The structure's ability to survive an earthquake can be adjudged in terms of the expected damage of the structure after the earthquake. Damage is a qualitative term and lots of subjectivity is thus involved in the quantification of damage to a structure. Damage can be quantified using a damage index. Several damage indices have been defined and established through series of correlation and evaluation works by many researchers. Damage indices are defined as functions, which are finally related to a particular structural damage. A number of response based damage indices are available to be used for seismic vulnerability assessment for given structural system. Damage indices best suited for the nonlinear structural analysis are the right candidate for the seismic vulnerability assessment of existing building because such building which are supposedly deficient or at least doubtful for its seismic capabilities are expected to cross elastic limit and will make excursions in inelastic range. The empirical damage indices are mainly based on observed seismic damages to similar type of construction during past earthquakes. These indices as based on damage surveys may be subjective and individual bias, but they provide enough and useful information on the overall seismic performance of structural systems. However, empirical evaluations do not lead to rationally predict the reserve strength and response characteristics of the structure with a specified degree of damage. The idea of describing the expected degree of damage to existing building under anticipated future earthquake by a number on a predefined damage scale in the form of damage index related to structural response calculated on a rational and simple base is attractive for such studies. Adaptive Static Pushover analyses and Reserve Strength Index (RSI) have been used to study seismic vulnerability of building cases representing symmetric as well as asymmetric structures considering 6-and 12 storey RCMRF buildings. © IAEME Publication.


Sinha A.K.,National Institute of Technology, Patna
International Journal of Civil Engineering and Technology | Year: 2017

Seismic vulnerability assessment and retrofitting of existing buildings is a key area in disaster resilient communities. Nature finds weaknesses left behind by mankind in structure and presents unambiguously in form of damage to such structures. Thus, Seismic damage concentrated at weak zones of structure speaks of as a report by a perfectionist 'The Nature'. The fact is beyond any doubt that the widespread damage to structures and immense losses are not due to just natural act but due to either our negligence or our ignorance. Earthquake Engineers can contribute in the noble cause of seismic disaster mitigation by assessing seismic vulnerability of existing buildings and providing the structure safe capacities against the anticipated demands during expected ground motion. There are scores of reasons for seismic vulnerability of existing infilled RCMRF buildings. Response of having infill and its impact over the seismic performance of Reinforced Concrete Moment Resisting Frame (RCMRF) have been studied in the paper using adaptive static pushover analyses considering 2-storey, 4-storey, 6-storey, 8-storey and 12- storey buildings. The earthquake resistant philosophy being practiced all over the world accepts structure going well into inelastic zone during strong motion. A nonlinear method centered on Pushover analysis has been proposed to quantify structural response in inelastic zone in view to assess seismic vulnerability. RC MRF with masonry infill presents very different situation. Study of uniform and non-uniform distribution of masonry infill using the Pushover based method provides enough guidelines to refine and supplement our knowledge in dealing with such structures as a rational seismic vulnerability presents roadmap for appropriate retrofit strategy for the existing buildings. © IAEME Publication.


Sinha A.K.,National Institute of Technology, Patna
International Journal of Civil Engineering and Technology | Year: 2017

Lots of research effort has been directed in recent times towards seismic vulnerability assessment. This is a part of seismic disaster mitigation. Earthquake Engineers can contribute in the noble cause by understanding and predicting structural behaviour under seismic action as close as the actual one and providing the structure safe capacities against all the possible demands during strong motion. Seismic vulnerability assessment exercise poses several difficulties as demand and capacity calculations depend not only on earthquake parameters but also on the structures. The present study is in the direction discussed above. Structures acquire asymmetry due to several reasons. Asymmetry in structures makes analysis of the seismic behaviour complicated. Seismic demand in peripheral elements is enhanced. Uniformity in load distribution gets disturbed. The paper first concentrates in understanding the complex behaviour of structure under asymmetric form. Then a simplified nonlinear pushover analysis has been used to find structural descriptors required in seismic vulnerability assessment. Deformation demand for different story for low-medium rise framed building has been found. Seismic load has been distributed in stories using triangular form. Then, force on frame has been distributed as per the distance from the center of rigidity and stiffness of the frame. Results have been produced in form of structural descriptors and eccentricity. The relationship with the damage is then established with eccentricity. The results are indicative of seismic vulnerability of asymmetric structure. The method proposed is an approximate method and the findings should be subjected to detailed evaluation and validation. The paper provides a simplified conceptual base to deal with the, otherwise, complicated analysis. © IAEME Publication.


Sinha A.K.,National Institute of Technology, Patna | Singh S.,National Institute of Technology, Patna
International Journal of Civil Engineering and Technology | Year: 2017

The increasing infrastructural growth incurs large investments and large section of society being served by them, it is necessary to make them safer against earthquakes and let people feel confident in their structures. The need for structural response control has gained pace in application around the globe. This paper discusses the use and effectiveness of one such device, friction dampers, for response control of structures. In this paper a non-linear time history analysis has been carried out on a 3D model of a 12 story RCC MRF building using 3-directional synthetic accelerogram. Two different cases of building models with and without friction dampers have been analyzed using ETABS. The response of the structure to seismic excitation in terms of absolute maximum displacement and story drift has been compared. Time history response plots have also been compared for various responses viz. roof displacement and acceleration, base shear and story shear forces, along with the various energy components and damping behavior. The results of the time history analysis are in close conformation with previous investigations and represent the effectiveness of dampers in improving the structural response as well as damping demand on structural systems. © IAEME Publication.


Sharma A.,National Institute of Technology, Patna
Disaster Advances | Year: 2017

This study explores architectural considerations necessary for restoration of heritage buildings damaged by earthquakes in the wake of damage to Kathmandu's Dharhara tower in the 2015 Nepal earthquake, through case studies of six selected historical buildings in Patna that were damaged by earthquake(s) and were subsequently repaired and/or restored. Based on the case studies, it was found that (1) the very features imparting monumental status to buildings are the ones most vulnerable during earthquakes; (2) every heritage building has a soul which should not be muzzled - restoration must ensure preservation of the soul of the building to protect its architectural and heritage value; (3) tourism potential and ensuing commercial value can finance the health and well-being of such monuments; (4) ensuring structural integrity during restoration is important for an "integral box action" of such buildings in future events and (5) even those buildings that are important historic public buildings and landmarks within a city or a town deserve the similar care in restoration as those that are under the ambit of UNESCO, ASI and other such organizations. The details of damages, restorations and reuse of some of these buildings, particularly the Sher Shahi mosque and Gol Ghar, are being reported for the first time ever. This study has enlisted several architectural considerations found necessary for restoration of buildings damaged by earthquake and has also suggested the preferred course of action for the severely damaged Dharhara Tower.


Mahato D.K.,National Institute of Technology, Patna | Sinha T.P.,Bose Institute of India
Journal of Materials Science: Materials in Electronics | Year: 2013

The polycrystalline praseodymium zinc zirconate Pr2ZnZrO 6 (PZZO) is synthesized at 1,150 C by means of solid state reaction technique. X-ray structural analysis confirmed the formation of a single phase monoclinic structure at room temperature. The nonzero intercept in the Nyquist plot indicates the presence of an arc for frequency higher than the maximum frequency measured (1 MHz). Comparative study of the impedance and modulus plot confirm the contribution from grain and grain-boundary and grain-boundary contribution dominates in the material. The activation energy of the compound calculated from imaginary part of impedance plot is found to be 0.442 eV which suggests that the polaron hopping is responsible for conduction mechanism in PZZO. Semiconducting behavior of the material is observed. Summerfield scaling shows a quite satisfying overlap of the data at different temperatures on a single master curve. © 2013 Springer Science+Business Media New York.

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