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Lattice thermal conduction in cadmium arsenide

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Chinese Physics B 2022年第11期31卷 424-430页

作者： R F Chinnappagoudra m D Kamatagi n R Patil n S Sankeshwar Department of Physics S.S.Government First Grade CollegeNargund-582207KarnatakaIndia Research Resource Centre Visvesvaraya Technological UniversityBelagavi-590018KarnatakIndia Department of Physics B V B College of Engineering and TechnologyHubliKarnataka 80031India Department of Physics&Electronics CHRIST(Deemed to be University)Bangalore-560029KarnatakaIndia

Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway *** acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon *** calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering *** systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for Tnd suggests a value of 0.2 for the Gruneisen *** is,however,found that for T>100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreement with the TC data over the wide temperature *** detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal management devices.

关键词： dirac semimetals Cd_(3)As_(2) thermal conductivity phonon scattering

A FLEXIBLE OBJECTIVE-COnSTRAInT APPROACH AnD A nEW ALGORITHm FOR COnSTRUCTInG THE PARETO FROnT OF mULTIOBJECTIVE OPTImIZATIOn PROBLEmS

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Acta mathematica Scientia 2024年第2期44卷 702-720页

作者： n.HOSEInPOOR m.GHAZnAVI Faculty of mathematical Sciences Shahrood University of TechnologyShahroodIran

In this article, a novel scalarization technique, called the improved objective-constraint approach, is introduced to find efficient solutions of a given multiobjective programming problem. The presented scalarized problem extends the objective-constraint problem. It is demonstrated that how adding variables to the scalarized problem, can lead to find conditions for (weakly, properly) Pareto optimal solutions. Applying the obtained necessary and sufficient conditions, two algorithms for generating the Pareto front approximation of bi-objective and three-objective programming problems are designed. These algorithms are easy to implement and can achieve an even approximation of (weakly, properly) Pareto optimal solutions. These algorithms can be generalized for optimization problems with more than three criterion functions, too. The effectiveness and capability of the algorithms are demonstrated in test problems.

关键词： multiobjective optimization Pareto front scalarization objective-constraint approach proper efficient solution

Weathering reflected by the chemical composition of alluvial soils from the Zeya and Selemdzha river valleys

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Science China Earth Sciences 2018年第5期61卷 604-613页

作者： O.A.SOROKInA m.n.GYSEV Institute of Geology and nature management Far East Branch Russian Academy of Sciences

The paper examines the chemical composition of alluvial soils from the Zeya and Selemdzha River valleys, one of the branch rivers in the Amur River basin. It has been established that the compositions of these soils are characterized by a relative shortage of practically all analyzed macro-and microelements as compared with UCC(upper continental crust) and PAAS(postArhean Australian average shale) compositions. The chemical composition of alluvial soils approximates that of the soils in nE China and Korea due to similar climatic and geographic conditions. On the basis of relationships between major and trace elements and peculiarities of trace elements concentration it is shown that the alluvial soils in the middle reaches of the Zeya River were formed by the sources largely transformed by chemical weathering processes. By comparison, the soils in the Selemdzha River and lower reaches of the Zeya River(below the Selemdzha River mouth) are dominated by material to a large degree reworked by the physical processes rather than chemical ones. This inference conforms with specific geological settings of the water-collector.

关键词： Alluvial soils Weathering indices Amur Zeya

Ameliorating the re/dehydrogenation behaviour of mgH2 by zinc titanate addition

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Journal of magnesium and Alloys 2023年第6期11卷 2205-2215页

作者： n.A.Ali n.A.Sazelee m.F.md Din m.m.nasef A.A.Jalil Haizen Liu m.Ismail Energy Storage Research Group Faculty of Ocean Engineering Technology and InformaticsUniversiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Department of Electrical and Electronic Engineering Faculty of EngineeringNational Defence University of MalaysiaKem Sungai BesiKuala LumpurMalaysia Center of Hydrogen Energy Institute of Future EnergyUniversiti Teknologi Malaysia81310 UTM Johor BahruJohorMalaysia Department of Chemical and Environmental Engineering Malaysia Japan International Institute of TechnologyUniversiti Teknologi MalaysiaJalan Sultan Yahya PetraKuala Lumpur 54100Malaysia Faculty of Chemical and Energy Engineering Universiti Teknologi Malaysia81310 UTM Johor BahruJohorMalaysia Guangxi novel Battery materials Research Center of Engineering Technology State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite StructuresSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured metal materials and Life-cycle Safety for Composite Structures Nanning 530004China

magnesium hydride(mgH_(2))is the most feasible and effective solid-state hydrogen storage material,which has excellent reversibility but initiates decomposing at high temperatures and has slow kinetics ***,zinc titanate(Zn_(2)TiO_(4))synthesised by the solid-state method was used as an additive to lower the initial temperature for dehydrogenation and enhance the re/dehydrogenation behaviour of mgH_(2).With the presence of Zn_(2)TiO_(4),the starting temperature for the dehydrogenation of mgH_(2)was remarkably lowered to around 290℃–305℃.In addition,within 300 s,the mgH_(2)–Zn_(2)TiO_(4)sample absorbed 5.0 wt.%of H_(2)and 2.2–3.6 wt.%H_(2)was liberated from the composite sample in 30 min,which is faster by 22–36 times than as-milled mgH_(2).The activation energy of the mgH_(2)for the dehydrogenation process was also downshifted to 105.5 k J/mol with the addition of Zn_(2)TiO_(4)indicating a decrease of 22%than as-milled mgH_(2).The superior behaviour of mgH_(2)was due to the formation of mg Zn_(2),mgO and mgTiO_(3),which are responsible for ameliorating the re/dehydrogenation behaviour of mgH_(2).These findings provide a new understanding of the hydrogen storage behaviour of the catalysed-mgH_(2)system.

关键词： Hydrogen storage Solid-state storage mgH_(2) Additive Zn_(2)TiO_(4)

Three-dimensional free vibration analysis of multi-directional functionally graded piezoelectric annular plates on elastic foundations via state space based differential quadrature method

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Applied mathematics and mechanics(English Edition) 2015年第4期36卷 439-464页

作者： m.H.YAS n.mOLOUDI Department of mechanical Engineering Razi University

The three-dimensional free vibration analysis of a multi-directional func- tionally graded piezoelectric （FGP） annular plate resting on two parameter （Pasternak） elastic foundations is investigated under different boundary conditions. The material properties are assumed to vary continuously along the radial and thickness directions and have exponent-law distribution. A semi-analytical approach named the state space based differential quadrature method （SSDQm） is used to provide an analytical solution along the thickness using the state space method （SSm） and an approximate solution along the radial direction using the one-dimensional differential quadrature method （DQm）. The influence of the Winkler and shear stiffness of the foundation~ the material property graded variations, and the circumferential wave number on the nomdimensional natural frequency of multi-directional FGP annular plates is studied.

关键词： multi-directional functionally graded piezoelectric annular plate freevibration

Shear band formation in shaped rheocast aluminium component at various plunger velocities

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Transactions of nonferrous metals Society of China 2010年第9期20卷 1749-1755页

作者： m.BLADH m.WESSn A.K.DAHLE Swerea SWECAST AB materials and manufacturing-Casting School of EngineeringJnkping University materials Engineering The University of Qu eensland

Significant progress has been made in recent years in understanding and modelling the rheology of semi-solid *** models show the effects of the microstructure in terms of size and morphology of globules on the material *** recently it has been shown that semi-solid metals can behave as compacted granular materials such as sand.A particular signature of such deformation is that the deformation becomes concentrated into shear bands which are 10-20 grains *** bands have also been observed in a range of cast ***, it has been clearly shown that shear bands in high pressure die cast (HPDC) products are also the results of Reynolds *** bands are also known to be a common feature in semi-solid metal *** segregation banding in semi-solid metal (SSm) material and its dependence of plunger velocity were *** castings were made with the RHEOmETALTm process with a range of different plunger *** microstructural characteristics were investigated, with a particular emphasis on shear *** is shown that ingate velocities influence the location and characteristics of the shear bands.

关键词： rheocasting shear bands segregation Al-alloys RHEOmETAL^Tm

On examining the predictive capabilities of two variants of the PInn in validating localized wave solutions in the generalized nonlinear Schr?dinger equation

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Communications in Theoretical Physics 2024年第11期76卷 161-174页

作者： K Thulasidharan n Sinthuja n Vishnu Priya m Senthilvelan Department of Physics Vellore Institute of TechnologyVellore-632014TamilnaduIndia Department of Physics Anna UniversityChennai-600025TamilnaduIndia Department of mathematics Indian Institute of ScienceBangalore 560012KarnatakaIndia Department of nonlinear Dynamics Bharathidasan UniversityTiruchirappalli-620024TamilnaduIndia

We introduce a novel neural network structure called strongly constrained theory-guided neural network(SCTgnn),to investigate the behaviour of the localized solutions of the generalized nonlinear Schr?dinger(nLS)*** equation comprises four physically significant nonlinear evolution equations,namely,the nLS,Hirota,Lakshmanan-Porsezian-Daniel and fifth-order nLS *** generalized nLS equation demonstrates nonlinear effects up to quintic order,indicating rich and complex dynamics in various fields of *** combining concepts from the physics-informed neural network and theory-guided neural network(Tgnn)models,the SCTgnn aims to enhance our understanding of complex phenomena,particularly within nonlinear systems that defy conventional *** begin,we employ the Tgnn method to predict the behaviour of localized waves,including solitons,rogue waves and breathers,within the generalized nLS *** then use the SCTgnn to predict the aforementioned localized solutions and calculate the mean square errors in both the SCTgnn and Tgnn in predicting these three localized *** findings reveal that both models excel in understanding complex behaviour and provide predictions across a wide variety of situations.

关键词： generalized nonlinear Schr?dinger equation soliton rogue waves breathers SCTgnn Tgnn

A parallel complex divider architecture based on DCD iterations for computing complex division in mVDR beamformer

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1124-1135页

作者： KIDAV Jayaraj U SIVA mangai n m PERUmAL m Pillai Karunya Institute of Technology and Sciences Coimbatore 641114India national Institute of Electronics and Information Technology Calicut 673601India

This paper presents a hardware architecture using mixed pipeline and parallel processing for complex division based on dichotomous coordinate descent(DCD) iterations. The objective of the proposed work is to achieve low-latency and resource optimized complex divider architecture in adaptive weight computation stage of minimum variance distortionless response(mVDR)algorithm. In this work, computation of complex division is modeled as a 2×2 linear equation solution problem and the DCD algorithm allows linear systems of equations to be solved with high degree of computational efficiency. The operations in the existing DCD algorithm are suitably parallel pipelined and the performance is optimized to 2 clock cycles per iteration. To improve the degree of parallelism, a parallel column vector read architecture is *** proposed work is implemented on the field programmable gate array(FPGA) platform and the results are compared with state-of-art literature. It concludes that the proposed architecture is suitable for complex division in adaptive weight computation stage of mVDR beamformer. We demonstrate the performance of the proposed architecture for mVDR beamformer employed in medical ultrasound imaging applications.

关键词： minimum variance distortionless response(mVDR) beamformer adaptive weight dichotomous coordinate descent(DCD) algorithm medical ultrasound imaging

Shear modulus and damping ratio of sand-granulated rubber mixtures

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Journal of Central South University 2015年第8期22卷 3159-3167页

作者： m.Ehsani n.Shariatmadari S.m.mirhosseini School of Civil Engineering Iran University of Science and Technology Department of Civil Engineering Amirkabir University of Technology

Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experiments were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids(D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specimens were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.

关键词： sand-rubber mixture shear modulus damping ratio low to high shear strain amplitude cyclic triaxial test torsionalresonant column test granular rubber