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Generalized Bleustein-Gulyaev type waves in layered porous piezoceramic structure

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Applied Mathematics and Mechanics(English Edition) 2015年第9期36卷 1223-1242页

作者： A.K.vASHISHTH A.DAHIYA v.gupta Department of Mathematics Kurukshetra University

The propagation of a Bleustein-Gulyaev （B-G） type wave in a structure consisting of multiple layers and a half-space of porous piezoelectric materials is theoreti- cally studied. The solutions of the problem in terms of the mechanical displacements and electric potential functions are obtained for each layer and the half-space. The dispersion equation is obtained for electrically open and shorted boundary conditions by use of the transfer matrix method. A peculiar kind of B-G waves is investigated, which can propagate only in the layer over the half-space. The relationship between the piezoelectric constants and the dielectric constants is found for the existence of a peculiar kind of propagation modes. The numerical results in terms of the phase velocity and the electromechanical coupling factor with different thicknesses of the layer stack are presented.

关键词： Bleustein-Gulyaev (B-G) type wave electro-mechanical coupling porouspiezoceramic transfer matrix

Ensembles vs. information theory: supporting science underuncertainty

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Frontiers of Earth Science 2018年第4期12卷 653-660页

作者： Grey S.NEARING Hoshin v.gupta University of Alabama Department of Geological SciencesTuscaloosaAL 35294-1152USA University of Arizona Department of Hydrology and Atmospheric SciencesTucsonAZ 85721-0158USA

Multi-model ensembles are one of the most common ways to deal with epistemic uncertainty in hydrology. This is a problem because there is no known way to sample models such that the resulting ensemble admits a measure that has any systematic (i.e., asymptotic, bounded, or consistent) relationship with uncertainty. Multi-model ensembles are effectively sensitivity analyses and cannot – even partially – quantify uncertainty. One consequence of this is that multi-model approaches cannot support a consistent scientific method – in particular, multi-model approaches yield unbounded errors in inference. In contrast, information theory supports a coherent hypothesis test that is robust to (i.e., bounded under) arbitrary epistemic uncertainty. This paper may be understood as advocating a procedure for hypothesis testing that does not require quantifying uncertainty, but is coherent and reliable (i.e., bounded) in the presence of arbitrary (unknown and unknowable) uncertainty. We conclude by offering some suggestions about how this proposed philosophy of science suggests new ways to conceptualize and construct simulation models of complex, dynamical systems.

关键词： information theory multi-model ensembles Bayesian methods uncertainty quantification hypothesis testing

Lithium bromide catalyzed solvent free method for synthesis of 2-substituted benzimidazoles and imidazopyridines

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Chinese Chemical Letters 2010年第5期21卷 519-523页

作者： Deepak v.Dekhane Shivaji S.Pawar Sunil v.gupta Murlidhar S.Shingare Shivaji N.Thore Department of Chemistry Vinyakrao Patil Mahavidyala VaijapurAurangabad 423701MSIndia Department of Chemistry Dr.Babasaheb Ambedkar Marathwada UniversityAurangabad 431004MSIndia

The first successful lithium bromide mediated solvent free condensation of arylenediamine and esters to obtain 2-substituted benzimidazole and imidazopyridine in good to excellent yields is described.

关键词： Benzimidazoles Arylenediamine Aliphatic esters Lithium bromide Imidazopyridines

Ranking environmental and edaphic attributes driving soil microbial community structure and activity with special attention to spatial and temporal scales

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mLife 2024年第1期3卷 21-41页

作者： vadakattu v.S.R.gupta James M.Tiedje CSIRO Agriculture&Food UrrbraeSouth AustraliaAustralia Centre for Microbial Ecology Michigan State UniversityEast LansingMichiganUSA

The incredibly complex soil microbial communities at small scales make their analysis and identification of reasons for the observed structures *** community structure is mainly a result of the inoculum(dispersal),the selective advantages of those organisms under the habitat-based environmental attributes,and the ability of those colonizers to sustain themselves over *** soil is protective,and its microbial inhabitants have long adapted to varied soil conditions,significant portions of the soil microbial community structure are likely ***,a substantial portion of the community will not correlate to often measured soil *** suggest that the drivers be ranked on the basis of their importance to the fundamental needs of the microbes:(i)those that supply energy,i.e.,organic carbon and electron acceptors;(i)environmental effectors or stressors,i.e.,pH,salt,drought,and toxic chemicals;(ii)macro-organism associations,i.e.,plants and their seasonality,animals and their fecal matter,and soil fauna;and(iv)nutrients,in order,N,P,and probably of lesser importance,other micronutrients,and *** relevance of drivers also varies with spatial and time scales,for example,aggregate to field to regional,and persistent to dynamic populations to transcripts,and with the extent of phylogenetic difference,hence phenotypic differences in organismal *** present a summary matrix to provide guidance on which drivers are important for particular studies,with special emphasis on a wide range of spatial and temporal scales,and illustrate this with genomic and population(rRNA gene)data from selected studies.

关键词： abundance community structure diversity functional microbiome microorganisms

Optimizing calcination of coal by-products for maximizing REE leaching recovery and minimizing Al,Ca,and Fe contamination

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Journal of Rare Earths 2024年第7期42卷 1354-1365,I0006页

作者： Tushar gupta Ahmad Nawab Rick Honaker MP Materials Mountain Pass Mine 67750 Bailey RoadMountain PassCA92366USA Department of Mining Engineering University of KentuckyLexingtonKY40506USA

High-temperature calcination is effective in improving the leaching characteristics of rare earth elements(REEs)from conventional REE-bearing minerals by transforming them into more leachable ***,the recovery of contaminants such as Al,Fe,and Ca also increases *** objective of the study was to maximize the REE extraction while minimizing the concentration of contaminant ions(Al,Ca,and Fe)in the leach *** density fractions of the coarse refuse from the Baker and Fire Clay seam coal refuse were pulverized to a top size of 180μm and used as a feedstock for the *** the samples generated from thermal treatment were leached at 1%(w/v)using 1.2 mol/L sulfuric acid at 75℃ for 2 *** results from a parametric program based on a Box-Behnken design were used for modeling and optimization of three operating parameters associated with the lab-scale calcination *** parameters included temperature(400-800℃),ramp rate(2-10℃/min)and holding time(0-120 min).It was determined that the calcination temperature was the most significant parameter influencing REE *** majority of the heavy rare earth elements(HREEs)were found to be present in an insoluble form in the calcination products and were marginally affected by thermal treatment.A strong correlation between light rare earth elements recovery(LREEs)and Al suggested a possible association with *** optimum operating conditions for high REE recovery with comparatively lower contaminant concentration for 1.6 specific gravity float and 2.2 sink fractions of Baker and Fire Clay seam material were determined to be at 776,800℃ and 407,800℃,calcining temperatures,respectively.A higher optimum temperature of 1.6 float fraction of Baker seam relative to Fire Clay seam material was due to elevated pyrite concentration in Baker seam *** treatment at 400℃ converted pyrite into a soluble intermedium iron oxide,resulting in a high Fe content in the ***

关键词： Calcination Optimization Rare earth elements Coal refuse

Microstructural image based convolutional neural networks for efficient prediction of full-field stress maps in short fiber polymer composites

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Defence Technology（防务技术） 2023年第6期24卷 58-82页

作者： S.gupta T.Mukhopadhyay v.Kushvaha Department of Civil Engineering Indian Institute of Technology JammuJ&KIndia Department of Aerospace Engineering Indian Institute of Technology KanpurUPIndia

The increased demand for superior materials has highlighted the need of investigating the mechanical properties of composites to achieve enhanced constitutive ***-reinforced polymer composites have emerged as an integral part of materials development with tailored mechanical ***,the complexity and heterogeneity of such composites make it considerably more challenging to have precise quantification of properties and attain an optimal design of structures through experimental and computational *** order to avoid the complex,cumbersome,and labor-intensive experimental and numerical modeling approaches,a machine learning(ML)model is proposed here such that it takes the microstructural image as input with a different range of Young’s modulus of carbon fibers and neat epoxy,and obtains output as visualization of the stress component S11(principal stress in the x-direction).For obtaining the training data of the ML model,a short carbon fiberfilled specimen under quasi-static tension is modeled based on 2D Representative Area Element(RAE)using finite element *** composite is inclusive of short carbon fibers with an aspect ratio of 7.5that are infilled in the epoxy systems at various random orientations and positions generated using the Simple Sequential Inhibition(SSI)*** study reveals that the pix2pix deep learning Convolutional Neural Network(CNN)model is robust enough to predict the stress fields in the composite for a given arrangement of short fibers filled in epoxy over the specified range of Young’s modulus with high *** CNN model achieves a correlation score of about 0.999 and L2 norm of less than 0.005 for a majority of the samples in the design spectrum,indicating excellent prediction *** this paper,we have focused on the stage-wise chronological development of the CNN model with optimized performance for predicting the full-field stress maps of the fiber-reinforced composite ***

关键词： Micromechanics of fiber-reinforced composites Machine learning assisted stress prediction Microstructural image-based machine learning CNN based stress analysis

Squeeze casting for metal alloys and composites:An overview of influence of process parameters on mechanical properties and microstructure

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China Foundry 2023年第2期20卷 148-158页

作者： Osarue Osaruene Edosa Francis Kunzi Tekweme Kapil gupta Department of Mechanical and Industrial Engineering Technology University of JohannesburgJohannesburgRepublic of South Africa Department of Mechanical Engineering College of Engineering and TechnologyWilliam V.S.Tubman UniversityHarperMaryland CountyRepublic of Liberia

Squeeze casting is a well-established and reliable process for fabricating high-integrity metallic alloys,bimetals,and *** quality and high performance of squeeze cast components are dependent on optimum casting *** selection of parameter values may adversely affect the quality of the *** squeeze cast components are generally subjected to secondary processing such as heat treatment,extrusion,and other bulk deformation processes to improve the microstructural features and mechanical *** treatment further refines the grains and reduces porosity,consequently improving tensile strength,and hardness;however,ductility *** paper provides a comprehensive review on studies concerning the influence of processing parameters on porosity,density,percentage elongation,strength,hardness,wear,and fracture of squeeze casting alloys,aiming to provide sufficient information on the squeeze casting process and the effects of processing parameters on product quality.

关键词： composites microstructure optimization porosity solidification squeeze casting

Unidirectionally aligned bright quantum rods films,using T-shape ligands,for LCD application

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Nano Research 2022年第6期15卷 5392-5401页

作者： Maksym F.Prodanov Chengbin Kang Swadesh K.gupta valerii v.vashchenko Yuhao Li Minchao Qin Xinhui Lu Abhishek K.Srivastava State Key Laboratory of Advanced Displays and Optoelectronics Technologies and Centre for Display Research Department of Electronics and Computer EngineeringThe Hong Kong University of Science and TechnologyClear Water BayHong Kong 999077Hong KongChina Department of Physics The Chinese University of Hong KongShatinHong Kong 999077Hong KongChina

Unidirectionally aligned nanorods(NRs)are of great importance for different applications,including displays,lighting,and ***,many alignment techniques were studied to align quantum rods(QRs).However,the brightness of these films,due to the limited concentration of aligned quantum rods in the film,is not enough for their implementation as brightness enhancement films(BEFs)in *** can be ascribed to the poor miscibility of quantum rods in polymer and strong concentration dependence of the polarized *** ligands of NR are very important for the alignment and *** this article,we proposed a ligand combination comprising T-shape promesogenic phosphonic acid,which on being photoaligned provides mutually parallel alignment of the quantum *** T-shape ligands enable the fabrication of hybrid films with a QRs concentration as high as 10 wt.%–20 wt.%retaining high brightness and luminescence polarization ***,we used these films in the in-plane switching(IPS)display backlight that shows the color gamut up to 121%of national television system committee(NTSC)(CIE1931),liquid-crystal display(LCD)efficiency up to 7.9%,power efficacy 103±2 nits/W,and the high brightness of~550±10 ***,the proposed ligands can be used for the alignment of a variety of nanorods.

关键词： quantum rods(QRs) ligands alignment display luminous efficiency

Designing an On-board Charger to Efficiently Charge Multiple Electric vehicles

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中国电气工程学报(英文) 2023年第2期9卷 38-56页

作者： Jyoti gupta Rakesh Maurya Sabha Raj Arya Department of Electrical Engineering Sardar Vallabhbhai National Institute of TechnologySurat 395007India

An on-board charger for efficiently charging multiple battery-operated electric vehicles(Evs)is *** has evolved as a single-input dual-output(SIDO)integrated boost-single ended primary inductor converter(SEPIC)fly-back converter,offering cost-effectiveness,reliability,and higher efficiency compared to conventional chargers with equivalent *** proposed system includes an additional regulated output terminal,in addition to an existing terminal for charging the Ev battery of a 4-wheeler,which can be used to charge another Ev battery,preferably a *** the aid of control techniques,unity power factor operations are obtained during constant-voltage(Cv)/constant-current(CC)charging for the grid-to-vehicle(G2v)operating *** mathematical modelling analysis,the proposed system is developed in a Matlab/Simulink environment,and the results are validated in a real-time simulator using *** proposed system is employed for charging the batteries of two Evs with capacities of 400 v,40 A·h and 48 v,52 A·h for the 4-wheeler and 2-wheeler,*** performance is investigated under different operating modes and over a wide range of supply voltage variations to ensure safe and reliable operation of the charger.

关键词： Continuous conduction mode(CCM) Cv/CC electric vehicles(Evs) power factor correction(PFC) single input dual output(SIDO) state of charge(SOC)