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Comparative study of travelling-wave and numerical solutions for the coupled short pulse (CSP) equation

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Chinese Physics B 2013年第5期22卷 60-66页

作者： Vik.s kumar R. k. Gupta Ram Jiwari School of Mathematics and Computer Applications Thapar University

The Lie symmetry analysis is performed for the coupled short plus （CSP） equation. We derive the infinitesimals that admit the classical symmetry group. Five types arise depending on the nature of the Lie symmetry generator. In all types, we find reductions in terms of system of ordinary differential equations, and exact solutions of the CSP equation are derived, which are compared with numerical solutions using the classical fourth-order Runge-k.tta scheme.

关键词： coupled short pulse (CSP) equation Lie symmetric analysis Runge-k.tta scheme exact solutions

Microstructure,mechanical and corrosion behavior of high strength AA7075aluminium alloy friction stir welds-Effect of post weld heat treatment

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Defence Technology（防务技术） 2015年第4期11卷 362-369页

作者： P.vijaya kumar G.Madhusudhan Reddy k.Srinivasa Rao Department of Mechanical Engineering R.I.T. Defence Metallurgical Research Laboratory Department of Metallurgical Engineering Andhra University

High strength aluminium alloy AA7075(Al-Zn-Mg-Cu) is a precipitate hardenable alloy widely used in the aerospace,defense,marine and automobile *** of the heat treatable aluminium alloys in all these sectors is ever-increasing owing to their excellent strength-toweight ratio and reasonably good corrosion *** shortage in corrosion resistance,however,usually poses negative concern about their reliability and lifetime when they service in the variable marine *** alloys also exhibit low weldability due to poor solidification microstructure,porosity in fusion zone and lose their mechanical properties when they are welded by fusion welding *** stir welding(FSW) is a reliable technique to retain the properties of the alloy as the joining tak.s place in the solid *** welds are susceptible to corrosion due to the microstructural changes in the weld nugget during *** this work.the effect of post weld treatments,viz.,peak.aging(T6) and retrogression & reaging(RRA),on the microstructure,mechanical properties and pitting corrosion has been *** stir welding of 8 mm-thick.AA7075 alloy was carried *** microstructural changes of base metal and nugget zone of friction stir welds were studied using optical microscopy,scanning electron microscopy and transmission electron *** and hardness test of base metal and welds has been carried *** corrosion resistance was determined through dynamic polarization *** was observed that the hardness and strength of weld were observed to be comparatively high in peak.aged(T6) condition but the welds showed poor corrosion *** resistance to pitting corrosion was improved and the mechanical properties were maintained by RRA *** resistance to pitting corrosion was improved in RRA condition with the minimum loss of weld strength.

关键词： 7075铝合金高强度铝合金搅拌摩擦焊耐腐蚀性热处理效果微观结构焊缝机械性能

Microstructure and pitting corrosion of armor grade AA7075 aluminum alloy friction stir weld nugget zone-Effect of post weld heat treatment and addition of boron carbide

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Defence Technology（防务技术） 2015年第2期11卷 166-173页

作者： P.vijaya kumar G.MADHUSUDHAN REDDY k.SRINIVASA RAO Department of Mechanical Engineering R.I.T. Defence Metallurgical Research Laboratory Department of Metallurgical Engineering Andhra University

Friction stir welding(FSW) of high strength aluminum alloys has been emerged as an alternative joining technique to avoid the problems during fusion *** recent times FSW is being used for armor grade AA7075 aluminum alloy in defense,aerospace and marine applications where it has to serve in non uniform loading and corrosive *** though friction stir welds of AA7075 alloy possess better mechanical properties but suffer from poor corrosion *** present work.involves use of retrogression and reaging(RRA) post weld heat treatment to improve the corrosion resistance of welded joints of aluminum *** attempt also has been made to change the chemical composition of the weld nugget by adding B4C nano particles with the aid of the FSW on a specially prepared base metal plate in butt *** effects of peak.aged condition(T6),RRA and addition of B4C nano particles on microstructure,hardness and pitting corrosion of nugget zone of the friction stir welds of AA7075 alloy have been *** though RRA improved the pitting corrosion resistance,its hardness was slightly *** improvement in pitting corrosion resistance was achieved with addition of boron carbide powder and post weld heat treatment of RRA.

关键词： 7075铝合金搅拌摩擦焊焊后热处理碳化硼颗粒抗点蚀微观结构装甲 7075合金

Control of BLDC motor using MRPID controller with modified landsman converter

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International Journal of Intelligent Computing and Cybernetics 2021年第4期14卷 664-685页

作者： Murali Dasari A.Srinivasula Reddy M.vijaya kumar Electrical Engineering Jawaharlal Nehru Technological University AnantapuramuAnanthapurIndia CMR Engineering College SecunderabadIndiaand Electrical and Electronics Engineering Jawaharlal Nehru Technological University AnantapuramuAnanthapurIndia

Purpose-The principal intention behind the activity is to regulate the speed,current and commutation of the brushless DC(BLDC)***,the authors can control the ***/methodology/approach-In order to regulate the current and speed of the motor,the Multiresolution PID(MRPID)controller is *** altered Landsman converter is utilized in this proposed suppression circuit,and the obligation cycle is acclimated to acquire the ideal DC-bus voltage dependent on the speed of the BLDC *** adaptive neuro-fuzzy inference system-elephant herding optimization(ANFISEHO)calculation mirrors the conduct of the procreant framework.in ***-Brushless DC motor’s dynamic properties are created,noticed and examined by MATLAB/Simulink.*** performance will be compared with existing genetic ***/value-The presented approach and performance will be compared with existing genetic algorithms and optimization of different structure of BLDC motor.

关键词： Brushless DC(BLDC)motors Elephant herding optimization(EHO) Adaptive neuro-fuzzy inference system(ANFIS) Landsman converter

Mechanical Properties and Microstructural Evolution of Bulk.UFG Al 2014 Alloy Processed Through Cryorolling and Warm Rolling

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Acta Metallurgica Sinica(English Letters) 2019年第7期32卷 845-856页

作者： Manoj kumar Pathak.Amit Joshi k. k. S. Mer R. Jayaganthan Department of Mechanical Engineering G. B. Pant Institute of Engineering and Technology Pauri-Garhwal 246194 India Department of Engineering Design. Indian Institute of Technology Madras Chennai 600036 India

Tensile properties, microstructural evolution and fracture toughness of Al 2014 alloy subjected to cryorolling followed by warm rolling (CR + WR) have been investigated in the present study. The solution-treated (ST) Al 2014 alloy is cryorolled followed by warm rolling process at different temperatures (110, 170 and 210 ℃). The mechanical properties and microstructural features of deformed and undeformed Al 2014 alloys were characterised by optical microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The CR + WR samples at 170 ℃ showed an improved hardness (179 HV), tensile (UTS 499 MPa, YS 457 MPa) and fracture toughness (k. = 37.49 MPa y/m, k.e = 37.39 MPa √m and J integral = 33.25 k./mm^2) with respect to ST alloy as measured from the tensile and fracture toughness test. The improved mechanical properties of CR + WR alloy are attributed to grain boundary strengthening, combined recovery and recrystallisation, precipitation hardening and dynamic ageing effect during the deformation. The precipitation of metastable spherical phase Al2Cu was responsible for the improved tensile and fracture properties of finegrained Al 2014 alloy observed in the present work.

关键词： Al alloys Ultrafine grains Fracture toughness

Design of a robust PID-PSS for an uncertain power system with simplified stability conditions

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Protection and Control of Modern Power Systems 2020年第1期5卷 222-237页

作者： vijaya Lak.hmi A.S.V Ramalinga Raju Manyala Siva kumar Mangipudi Department of EEE G.V.P College of Engineering for WomenVisakhapatnamIndia Department of EEE JNTU KakinadaKakinadaIndia Department of EEE Gudlavalleru Engineering CollegeGudlavalleruAndhra PradeshIndia

In a deregulated power system uncertainty exists and lack.of sufficient damping can lead to Low FrequencyOscillations (LFO). The problem can be addressed using robust Power System Stabilizers (PSS). In this paper, anoptimal procedure to design a robust PID-PSS using interval arithmetic for the Single Machine Infinite Bus (SMIB)power system is proposed. The interval modelling captures the wide variations of operating conditions in boundsof system coefficients. In the proposed design procedure, simple and new closed loop stability conditions for anSMIB interval system are developed and are used to design an optimum PID-PSS for improving the performance ofan SMIB system. The optimum PID-PSS is attained by tuning the parameters using the FMINCON tool provided inMATLAB. The robustness of the proposed PID-PSS design is validated and compared to other notable methods inthe literature when the system is subjected to different uncertainties. The simulation results and performance errorvalues show the effectiveness of the proposed robust PID-PSS controller.

关键词： Low frequency oscillations Uncertainty Power system stabilizer Robust controller Interval systems

A MULTIGRID-ACCELERATED THREE-DIMENSIONAL TRANSIENT-FLOW CODE AND ITS APPLICATION TO A NEW TEST PROBLEM

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Journal of Hydrodynamics 2010年第6期22卷 838-846页

作者： kumar D.Santhosh DASS Anoop k. DEWAN Anupam School of Mechanical and Building Science Vellore Institute of TechnologyVellore-632014India Department of Mechanical Engineering Indian Institute of Technology GuwahatiGuwahati-781039India Department of Applied Mechanics Indian Institute of Technology Delhi Hauz KhasNew Delhi-110016India

A multigrid-assisted solver tbr the three-dimensional time-dependent incompressible Navier-Stok.s equations on graded Cartesian meshes is developed. The spatial accuracy is third-order for the convective terms and fourth-order for the viscous terms, and a fractional-step strategy ensures second-order time accuracy. To achieve good time-wise efficiency a multigrid technique is used to solve the highly time-consuming pressure-Poisson equation that requires to be solved at every time step. The speed-up achieved by multigrid is shown in tabular form. The performance and accuracy of the code are first ascertained by computing the flow in a single-sided lid-driven cubic cavity with good grid-economy and comparing the results available in the literature. The code, thus validated, is then applied to a new test problem we propose and various transient and asymptotically obtained steady-state results are presented. Given the care tak.n to establish the credibility of the code and the good spatio-temporal accuracy of the discretization, these results are accurate and may be used for ascertaining the performance of any computational algorithm applied to this test problem.

关键词： incompressible flows three-dimensional cavity flow fractional-step method multigrid method Taylor-Gorier-Lik. (TGL) vortices grid transformation

Deep Learning Enabled Object Detection and Track.ng Model for Big Data Environment

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Computers, Materials & Continua 2022年第11期73卷 2541-2554页

作者： k.vijaya kumar E.Laxmi Lydia Ashit kumar Dutta Velmurugan Subbiah Parvathy Gobi Ramasamy Irina V.Pustok.ina Denis A.Pustok.in Department of Computer Science and Engineering Vignan’s Institute of Engineering for WomenVisakhapatnam530049India Department of Computer Science and Engineering Vignan’s Institute of Information TechnologyVisakhapatnam530049India Department of Computer Science and Information System College of Applied SciencesAlMaarefa UniversityRiyadh11597Kingdom of Saudi Arabia Department of Electronics and Communication Engineering Kalasalingam Academy of Research and EducationKrishnankoil626126TamilnaduIndia Department of Computer Science Christ UniversityBangalore560029India Department of Entrepreneurship and Logistics Plekhanov Russian University of Economics117997MoscowRussia Department of Logistics State University of ManagementMoscow109542Russia

Recently,big data becomes evitable due to massive increase in the generation of data in real time ***,object detection and track.ng applications becomes popular among research communities and finds useful in different applications namely vehicle navigation,augmented reality,surveillance,*** paper introduces an effective deep learning based object track.r using Automated Image Annotation with Inception v2 based Faster RCNN(AIA-IFRCNN)model in big data *** AIA-IFRCNN model annotates the images by Discriminative Correlation Filter(DCF)with Channel and Spatial Reliability track.r(CSR),named DCF-CSRT *** AIA-IFRCNN technique employs Faster RCNN for object detection and track.ng,which comprises region proposal network.RPN)and Fast *** addition,inception v2 model is applied as a shared convolution neural network.CNN)to generate the feature ***,softmax layer is applied to perform classification *** effectiveness of the AIA-IFRCNN method undergoes experimentation against a benchmark.dataset and the results are assessed under diverse aspects with maximum detection accuracy of 97.77%.

关键词： Object detection track.ng convolutional neural network inception v2 image annotation

Adaptations of phytoplank.on in the Indian Ocean sector of the Southern Ocean during austral summer of 1998-2014

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Frontiers of Earth Science 2015年第4期9卷 742-752页

作者： R. k. MISHRA R. k. NAIk.N. ANIL kumar ESSO-National Centre for Antarctic and Ocean Research Ministry of Earth Sciences (MoES) Vasco-da-Gama Goa India

This study investigates the effects of light and temperature on the surface water diatoms and chloro- phytes, phytoplank.on in the Indian Ocean sector of the Southern Ocean （SO） during the austral summer of 1998- 2014. Significant longitudinal variations in hydrographic and biological parameters were observed at the Sub tropical front （STF）, Sub Antarctic front （SAF） and Polar front （PF） along 56°E-58°E. The concentrations of total surface chlorophyll a （Chl a）, diatoms, and chlorophytes measured by the National Aeronautics Space Agency （NASA） estimated by the Sea-Viewing Wide Field-of- View Sensors （SeaWiFS）, the Moderate Resolution Imaging Spectro Radiometer （MODIS）, and the NASA Ocean Biological Model （NOBM） were used in the study. Variations in the concentration of total Chl a was remark.ble amongst the fronts during the study period. The contribution of diatoms to the total concentration of surface Chl a increased towards south from the STF to the PF while it decreased in the case of chlorophytes. The maximum photosynthetically active radiation （PAR） was observed at the STF and it progressively decreased to the PF through the SAF. At the PF region the contribution of diatoms to the total Chl a biomass was ≥80%. On the other hand, the chlorophytes showed a contrary distribution pattern with ≥ 70% of the total Chl a biomass recorded at the STF which gradually decreased towards the PF, mainly attributed to the temperate adaptation. This clearly reveals that the trend of diatoms increased at the STF and decreased at the SAF and the PF. Further, the trend of chlorophytes was increased at the STF, SAF and PF with a shift in the community in the frontal system of the Indian Ocean sector of the SO.

关键词： chlorophyll a diatoms chlorophytes SST,PAR Southern Ocean