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EVOLUTION AND INTERACTION OF δ-WAVES IN THE ZERO-PRESSURE GAS DYNAMICS SYSTEM

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Acta Mathematica Scientia 2024年第5期44卷 1801-1836页

作者： abhishek DAS K.T.JOSEPH Centre for Data Science Institute of Technical Education and Research(ITER)Siksha‘O’Anusandhan(Deemed to be University)BhubaneswarOdisha751030India Centre for Applicable Mathematics Tata Institute of Fundamental ResearchSharada NagarBangalore560065KarnatakaIndia

Evolution and interaction of plane waves of the multidimensional zero-pressure gas dynamics system leads to the study of the corresponding one dimensional *** this paper,we study the initial value problem for one dimensional zero-pressure gas dynamics *** the first equation is the Burgers equation and the second one is the continuity *** consider the solution with initial data in the space of bounded Borel *** we prove a general existence result in the algebra of generalized functions of *** we study in detail special solutions withδ-measures as initial *** study interaction of waves originating from initial data concentrated on two point sources and interaction with classical shock/rarefaction *** gives an understanding of plane-wave interactions in the multidimensional *** use the vanishing viscosity method in our analysis as this gives the physical solution.

关键词： zero-pressure gas dynamics delta-waves interaction of waves

Implications of REE incorporation and host sediment influence on the origin and growth processes of ferromanganese nodules from Central Indian Ocean Basin

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Geoscience Frontiers 2021年第3期12卷 609-623页

作者： Simontini Sensarma abhishek Saha Arghya Hazra CSIR-National Institute of Oceanography Dona PaulaGoa 403004India Indian Institute of Science BangaloreKarnataka 560012India School of Earth Ocean and Atmospheric SciencesGoa UniversityGoa 403206India

This study presents new major,trace and REE data for thirty-five ferromanganese nodules recovered from areas representing three different sediment types(siliceous,red clay and their transition zone)in the Central Indian Ocean Basin(CIOB)to address their genetic aspects,classification,growth rate,nature of host sediments and influence of REE in the processes of nodule *** nodules from CIOB are mostly either hydrogenetic(metals coming from oxygenated bottom water)and diagenetic(metals coming from suboxic sediment pore water)or a combination of both,depending on the source of supply of ***,a number of biogeochemical processes mediate this supply of metals which again changes from time to time,making the nodule growth process highly *** study suggests that at the initial stage of nodule growth,host sediments do not play much role in controlling the growth processes for which REEs can enter both Mn and Fe oxyhydroxide phases ***,the bottom water signature is imprinted in these early formed nodules irrespective of their host sediment substrate but with gradual growth and burial in the sediment,the main mode of metal enrichment becomes diagenetic through sediment pore *** tends to increase the concentration of Mn,Ni and Cu over other elements which are retained in the sediment *** the REEs,Ce concentration of the nodules shows significant positive anomaly due to variation in redox potential and hence its magnitude can be used to get an idea about the metal enrichment procedure and the genetic type of the ***,based on host sediment only,not much difference is found in the magnitude of Ce anomaly in these *** the other hand,discrimination diagram,based on HFSE and REY chemistry,indicates that most of these nodules are of diagenetic origin under oxic condition with a trend towards hydrogenetic ***,the genetic type of the ferromanganese nodules from the CIOB are more effectively differentiated

关键词： Central Indian Ocean Basin Ferromanganese nodules Deep-sea sediments Rare earth elements Geochemical discrimination

Three-phase AC-DC Converter for Direct-drive PMSG-based Wind Energy Conversion System

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Journal of Modern Power Systems and Clean Energy 2023年第2期11卷 589-598页

作者： Kumar abhishek Singh Ayushi Chaudhary Kalpana Chaudhary Department of Electrical Engineering Indian Institute TechnologyVaranasiIndia Department of Electrical Engineering Indian Institute TechnologyKanpurIndia

In this paper,a wind energy conversion system(WECS)is presented for the electrification of rural areas with wind energy availability.A three-phase AC-DC converter based on a bridgeless Cuk converter is used for power extraction from the permanent magnet synchronous generator(PMSG).The bridgeless topology enables the elimination of the front-end diode bridge rectifier(DBR).Moreover,the converter has fewer components,simple control,and high efficiency,making it suitable for a small-scale WECS.A squirrel cage induction motor(SCIM)is used to emulate a MOD-2 wind turbine to implement the PMSG-based WECS.A direct-drive eight-pole PMSG is used in this study;thus,a low-input-voltage system is *** converter is designed to operate in the discontinuous inductor current mode(DICM)for inherent power factor correction(PFC)and the maximum power point tracking(MPPT)is achieved through the tip-speed ratio(TSR)*** performance of the developed system is analyzed through simulation,and a 500 W hardware prototype is developed and tested in different wind speed conditions.

关键词： Permanent magnet synchronous generator(PMSG) three-phase AC-DC converter wind energy conversion system(WECS) wind turbine emulator

Challenges,opportunities,and advances related to COVID-19 classification based on deep learning

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Data Science and Management 2023年第2期6卷 98-109页

作者： abhishek Agnihotri Narendra Kohli Department of Computer Science and Engineering Harcourt Butler Technical UniversityKanpur208002India

The novel coronavirus disease,or COVID-19,is a hazardous *** is endangering the lives of many people living in more than two hundred *** directly affects the *** general,two main imaging modalities,i.e.,computed tomography(CT)and chest x-ray(CXR)are used to achieve a speedy and reliable medical *** the coronavirus in medical images is exceedingly difficult for diagnosis,assessment,and *** is demanding,time-consuming,and subject to human *** biological disciplines,excellent performance can be achieved by employing artificial intelligence(AI)*** a subfield of AI,deep learning(DL)networks have drawn considerable attention than standard machine learning(ML)*** models automatically carry out all the steps of feature extraction,feature selection,and *** study has performed comprehensive analysis of coronavirus classification using CXR and CT imaging modalities using DL ***,we have discussed how transfer learning is helpful in this ***,the problem of designing and implementing a system using computer-aided diagnostic(CAD)to find COVID-19 using DL approaches highlighted a future research possibility.

关键词： Classification COVID-19 Coronavirus Deep learning CAD system

Vasectomy reversal： a clinical update

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Asian Journal of Andrology 2016年第3期18卷 365-371,I0007页

作者： abhishek P Patel Ryan P Smith Department of Urology University of Virginia Charlottesville VA 22908-0422 USA.

Vasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and places a larger financial strain on the patient since it is usually not covered by insurance. Interest in this procedure has increased since the operating microscope became available in the 1970s, which consequently led to improved patency and pregnancy rates following the procedure. In this clinical update, we discuss patient evaluation, variables that may influence reversal success rates, factors to consider in choosing to perform vasovasostomy versus vasoepididymostomy, and the usefulness of vasectomy reversal to alleviate postvasectomy pain syndrome. We also review the use of robotics for vasectomy reversal and other novel techniques and instrumentation that have emerged in recent years to aid in the success of this surgery.

关键词： epididymovasostomy microsurgery postvasectomy orchialgia postvasectomy pain syndrome vas deferens vasectomy vasectomy reversal vasoepididymostomy vasovasostomy

Advances in endobariatrics:past,present,and future

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Gastroenterology Report 2023年第1期11卷 140-150页

作者： abhishek Shenoy Allison R.Schulman Division of Gastroenterology and Hepatology University of MichiganMichigan MedicineAnn ArborMIUSA Department of Surgery University of MichiganMichigan MedicineAnn ArborMIUSA

The obesity epidemic in the USA and worldwide is well documented and continues to *** metabolic and bariatric therapies may offer a less invasive approach than surgical *** article will review advances in endobariatrics over the last several decades,addressing the past and current state of bariatric and metabolic *** and Drug Administration-cleared devices and interventions currently under investigation are described including gastric devices,gastric remodeling procedures,small-bowel devices,duodenal ablation,as well as procedures to address weight regain after bariatric *** studies evaluating gastric and duodenal combination therapy,adjunctive pharmacotherapy,as well as individualized precision-health algorithms are underway.

关键词： metabolic devices endoscopic sleeve gastroplasty obesity endobariatrics bariatric therapy

Numerical Analysis of Phase Change and Container Materials for Thermal Energy Storage in the Storage Tank of Solar Water Heating System

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Journal of Thermal Science 2024年第2期33卷 408-421页

作者： SINGH Shailendra ANAND abhishek SHUKLA Amritanshu SHARMA Atul Non-Conventional Energy Laboratory Rajiv Gandhi Institute of Petroleum TechnologyJais Amethi229304India

This study evaluates the effectiveness of phase change materials(PCMs) inside a storage tank of warm water for solar water heating(SWH) system through the theoretical simulation based on the experimental model of *** et *** model is explained by five fundamental equations for the calculation of various parameters like the effectiveness of PCMs,the mass of hot water,total heat content,and duration of *** study simulated eleven PCMs to analyze their effectiveness like Sodium hydrogen phosphate dodecahydrate(SHPD),OM 37,N-Eicosane(NE),Lauric acid(LA),Paraffin wax(PW),OM 48,Paraffin wax C_(20-33)(PW-C20-33),Sodium acetate trihydrate(SAT),Palmitic acid(PA),Myristic acid(MA),and Stearic acid(SA).Among all PCMs,the SHPD has found the highest value of effectiveness factor of ***,it is the most recommended PCM for the storage tank of the SWH *** study also includes the melt fraction analysis of all enumerated PCMs corresponding to container materials of stainless steel,glass,aluminum mixed,tin,aluminum,and *** melt fraction analysis is performed by making a coding program in the FORTRAN programming *** the analysis,copper container material is found to have high melting rate for all PCMs so it is superior to other container materials.

关键词： theoretical model solar water heating system phase change material effectiveness factor melt fraction

Preparation,crystallization,microstructure and dielectric properties of lead bismuth titanate borosilicate glass ceramics

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Journal of Advanced Ceramics 2014年第3期3卷 194-206页

作者： Chandkiram RGAUTAM abhishek MADHESHIYA Ranabrata MAZUMDER Advanced Glass and Glass Ceramic Research Laboratory Department of PhysicsUniversity of LucknowLucknow 226007India Department of Ceramic Engineering National Institute of TechnologyRouerkela 769008India

Various bulk and transparent glasses were prepared by rapid melt quenching technique in the glass system 55[(Pb_(x)Bi_(1-x))TiO_(3)]-44[2Si_(O)2B_(2)O_(3)]-La2O3(x=0-0.7).The X-ray diffraction(XRD)studies of the glass samples confirmed the amorphous *** differential thermal analyses(DTA)were carried out from room temperature to 900℃with a heating rate of 10℃/*** DTA patterns of the samples showed one or more exothermic sharp peaks shifting towards lower temperature side with increasing concentration of bismuth oxide(BiO).On the basis of DTA results,the solid solution of bismuth titanum oxide(Bi_(2)Ti_(2)O_(7))/lead bismuth titanium oxide(Pb3Bi4Ti6O21)was precipitated in borosilicate glassy matrix as a major *** glasses were subjected to 4 h and 8 h heat treatment schedules to convert into glass *** analysis of these glass ceramic samples showed that the major crystalline phase of the entire glass ceramic samples with 0≤x≤0.5 is found to have cubic crystal structure,while it is tetragonal for glass ceramic sample with x=*** scanning electron microscopy(SEM)micrographs indicated the uniform distribution of Bi_(2)Ti_(2)O_(7)and Pb3Bi4Ti6O21 crystallites in the glassy matrix.

关键词： lead bismuth titanate differential thermal analysis(DTA) crystallization scanning electron microscopy(SEM) dielectric behavior

Effects of defects on the electronic properties of WTe_2 armchair nanoribbons

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Journal of Semiconductors 2014年第11期35卷 10-15页

作者： Bahniman Ghosh abhishek Gupta Bhupesh Bishnoi Microelectronics Research Center 10100Burnet RoadBldg.160University of Texas at AustinAustinTX78758USA Department of Electrical Engineering Indian Institute of Technology Kanpur

We have investigated the electronic properties of WTe2 armchair nanoribbons with defects. WTe2 nanoribbons can be categorized depending on the edge structure in two types： armchair and zigzag. WTe2 in its bulk form has an indirect band gap but nanoribbons and nanosheets of WTe2 have direct band gaps. Interestingly, the zigzag nanoribbon is metallic while the armchair nanoribbons are semiconducting. Thus they can find applications in device fabrication. Therefore, it is very important to study the effect of defects on the electronic properties of the armchair nanoribbons as these defects can impair the device properties and characteristics. We have considered defects such as： vacancy, rough edge, wrap, ripple and twist in this work. We report the band gap variation with these defects. We have also studied the change in band gap and total energy with varying degrees of wrap, ripple and twist.

关键词： electronic property WTe2 armchair nanoribbons defects