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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 Tsuggests 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

Influence of the wakes of rotating spokes on the performance of a turbine exhaust diffuser

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journal of Thermal science 2010年第3期19卷 206-210页

作者： m.Kuschel j.r.seume Institute of Turbomachinery and Fluid Dynamics Leibniz University HannoverD-30167 HannoverGermany

The design of turbine exhaust diffusers is still commonly based upon conservative design charts which do not consider the influence of the components installed upstream such as the last turbine *** on investigations with different spoke wheels which approximate the blade wakes of the last turbine stage,the influence of a rotating bladed disc on the flow in a exhaust diffuser is *** pressure recovery for an annual diffuser with 15° half cone angle and the 5 mm spoke wheel used in the model test is very high and nearly independent on the rotational speed and the corresponding strouhal *** a 20° annual diffuser,the pressure recovery increases with strouhal number

关键词： turbine exhaust diffuser rotating wakes separation

magnesium-based nanocomposites:A review from mechanical,creep and fatigue properties

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journal of magnesium and Alloys 2023年第8期11卷 2655-2687页

作者： s.Abazari A.shamsipur H.r.Bakhsheshi-rad j.W.Drelich j.Goldman s.sharif A.F.Ismail m.razzaghi Department of materials and metallurgical Engineering Amirkabir University of TechnologyTehranIran Advanced materials research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran Department of materials science and Engineering Michigan Technological UniversityHoughtonMI 49931USA Department of Biomedical Engineering Michigan Technological UniversityHoughtonMI 49931USA Advanced manufacturing research Group Faculty of Mechanical EngineeringUniversiti Teknologi MalaysiaJohor Bahru 81310JohorMalaysia Advanced membrane Technology research Center(AmTEC) Universiti Teknologi MalaysiaJohor Bahru 81310JohorMalaysia

The addition of nanoscale additions to magnesium(mg)based alloys can boost mechanical characteristics without noticeably decreasing *** mg is the lightest structural material,the mg-based nanocomposites(NCs)with improved mechanical properties are appealing materials for lightweight structural *** contrast to conventional mg-based composites,the incorporation of nano-sized reinforcing particles noticeably boosts the strength of mg-based nanocomposites without significantly reducing the *** present article reviews mg-based metal matrix nanocomposites(mmNCs)with metallic and ceramic additions,fabricated via both solid-based(sintering and powder metallurgy)and liquid-based(disintegrated melt deposition)*** also reviews strengthening models and mechanisms that have been proposed to explain the improved mechanical characteristics of mg-based alloys and ***,synergistic strengthening mecha-nisms in mg matrix nanocomposites and the dominant equations for quantitatively predicting mechanical properties are ***,this study offers an overview of the creep and fatigue behavior of mg-based alloys and nanocomposites using both traditional(uniaxial)and depth-sensing indentation *** potential applications of magnesium-based alloys and nanocomposites are also surveyed.

关键词： magnesium-based nanocomposites Nanoreinforcement strengthening mechanisms Creep properties Fatigue properties

mHD flow of a visco-elastic fluid through a porous medium between infinite parallel plates with time dependent suction

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journal of Hydrodynamics 2015年第5期27卷 738-747页

作者： BAAG s. ACHArYA m.r. DAsH G.C. mIsHrA s.r. Department of Physics College of Basic Science and HumanitiesOUAT Department of mathematics ITER SOA University

This work provides a comprehensive theoretical analysis of mHD unsteady free convection viscoelastic fluid flow through a porous medium. The medium is treated as incompressible and optically transparent. The flow of the fluid is initiated by shearing action of the moving wall with time dependent suction. radiative heat flow is considered in temperature equation. The coupled nonlinear problem has been solved asymptotically. Approximate solutions have been obtained for the mean velocity, mean temperature using multi parameter perturbation technique. The originality of the present study is to investigate the effect of viscoelastic property of the fluid（Walters B？ model） on the flow and heat transfer phenomena when the flow is permeated through a porous medium with uniform porous matrix subject to transverse magnetic field and time dependent fluctuative suction at the boundary surface. The case of viscous flow has been discussed as a particular case on comparison with the result reported earlier and it is in good agreement. Flow reversal is indicated incase of viscoelastic fluid with high heat capacity in the presence of magnetic field. The higher cooling of the plate in case of viscoelastic flow also causes a flow reversal.

关键词： viscoelastic liquid porosity radiation parameter time dependent suction

Analysis of the sBP-sAT stabilization for Finite Element methods Part Ⅱ:Entropy stability

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Communications on Applied mathematics and Computation 2023年第2期5卷 573-595页

作者： r.Abgrall j.Nordström P.Öffner s.Tokareva Institute of mathematics University of ZurichWinterthurerstrasse 1908057 ZurichSwitzerland Department of mathematics Computational MathematicsLinköping University58183 LinköpingSweden Department of mathematics and Applied mathematics University of JohannesburgAuckland ParkP.O.Box 524Johannesburg 2006South Africa Theoretical Division Applied Mathematics and Plasma Physics Group(T-5)Los Alamos National LaboratoryLos AlamosNM 87545USA

In the hyperbolic research community,there exists the strong belief that a continuous Galerkin scheme is notoriously unstable and additional stabilization terms have to be added to guarantee *** the first part of the series[6],the application of simultaneous approximation terms for linear problems is investigated where the boundary conditions are imposed *** applying this technique,the authors demonstrate that a pure continu-ous Galerkin scheme is indeed linearly stable if the boundary conditions are imposed in the correct *** this work,we extend this investigation to the nonlinear case and focus on entropy *** switching to entropy variables,we provide an estimation of the boundary operators also for nonlinear problems,that guarantee *** numerical simulations,we verify our theoretical analysis.

关键词： Continuous Galerkin Entropy stability simultaneous approximation terms Initial-boundary value problem Hyperbolic conservation laws

Particle size Distribution and Characterization of High siliceous and microporous materials

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journal of materials science & Technology 2005年第4期21卷 563-570页

作者： s.KDurrani j.Akhtar m.Ahmad m.j.moughal Nuclear materials Division Pakistan Institute of Nuclear Science and Technology P.O. Nilore Islamabad PakistanNuclear Materials Division Pakistan Institute of Nuclear Science and Technology P.O. Nilore Islamabad PakistanNuclear Physics Divisions Pakistan Institute of Nuclear Science and Technology P.O. Nilore Islamaad PakistanNuclear Materials Division Pakistan Institute of Nuclear Science and Technology P.O. Nilore. Islamabad. Pakistan

Particle size, textural and surface characteristics influence some major technological properties of high siliceous aluminosilicate zeolite and sillicoaluminophosphate （sAPO） microporous materials. A comparative study was furnished for measuring surface characteristics, particle size and particle size distribution using particle size analyzer （PsA） and scanning electron microscope （sEm）. The PsA is capable of measuring particle diameter in micron range. The results of these techniques for estimation of particle size were compared and correlated statistically. student t-test and variance ratio test （F-test） methods were performed for the significance of results by the analysis of variance （ANONA） and multiple-range tests. Textural and surface characteristics were evaluated by Brunauer, Emmett ＆ Teller （BET） volumetric technique and v-αs plotting method. The textural results shows that the external surface area and micropore volume of microporous materials were higher than those of the high siliceous zeolites and its zeotype materials.

关键词： synthesis High siliceous zeolites microporous materials Particle size distribution micropore volume sEm

A New Process for Titanium Aluminides Production from TiO_2

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journal of materials science & Technology 2007年第3期23卷 367-372页

作者： A.r.Kamali H.razavizadeh s.m.m.Hadavi Department of materials and metallurgy Engineering IUsT University Department of Chemical and materials Engineering maleke Ashtar University

This paper describes a new process for producing titanium aluminides, in particular TiAl, from TiO2 raw material. On the basis of obtained results, the non-completed reaction of TiO2 with Al and Ca in a special reaction vessel results in the production of granulates of titanium aluminides especially Ti3Al and other Ti- Al phases as the metallic product and Ca12Al14O33 as the non-metallic product. By adding KClO4 in the mixture, a nearly completed reaction can be carried out. The products of this reaction are titanium aluminide particularly TiAl as the metallic part and CaAl4O7 （grossite） as the non-metallic slag part. Both product and slag are produced in a separated form. This process, called KrH-method is described in this article. The scanning electron microscopic microstructure of metallic part of the product shows different phases： the matrix phase is TiAI, where the needle form precipitation is TiAl2 and the plate form precipitation includes TiAI and Ti3Al phases. The microstructure of the remelted metallic part indicates dendritic phase with a lamellar structure comprising of TiAl and Ti3Al phases. The interdendritic phase of TiAI is also seen.

关键词： Titanium aluminide Titanium dioxide Grossite KrH process

Investigation on the dissolution of η phase in a cast Ni-based superalloy

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International journal of minerals,metallurgy and materials 2013年第1期20卷 42-48页

作者： m.r. jahangiri H. Arabi s.m.A. Boutorabi school of metallurgy and materials Engineering Iran University of Science and Technology metallurgy Department Niroo Research Institute Center of Excellence for Advanced materials & Processing Iran University of Science and Technology

The dissolution behavior of rI phase has been investigated in a cast Ni-based superalloy. The results showed that the platelets and blocks of η phase were formed within the interdendritic regions of the microstructure. Applying standard solution annealing at 1150-1160℃ for a period of 4 h did not result in the complete dissolution of η phase. For the complete dissolution of η phase without residual incipient melting, a 2-step solution annealing has been recommended. After dissolution at high tem- peratures, the TI phase transforms to two mC-type carbides： one is enriched in Ti, Nb, and Ta, and the other is of （Zr,Ti）C type.

关键词： superalloys nickel alloys phase transitions dissolution heat treatment carbides

multi-scale magnetic resonance measurements and validation of Discrete Element model simulations

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Particuology 2011年第4期9卷 330-341页

作者： Christoph r. müller Daniel j. Holland james r. Third Andrew j. sederman john s. Dennis Lynn F. Gladden Institute of Energy Technology Department of Mechanical and Process Engineering Department of Chemical Engineering and Biotechnology University of Cambridge

This short review describes the capabilities of magnetic resonance （mr） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization regimes. The unique capability of mr to not only image the solids＇ distribution （voidage） but also the velocity of the particulate phase is clearly shown. It is demonstrated that mr can provide measurements over different length and time scales. With the mr equipment used for the studies summarized here, temporal and spatial scales range from sub-millisecond to hours and from a few hundred micrometres to a few centimetres, respectively. Besides providing crucial data required for an improved understanding of the underlying physics of granular flows, multi-scale mr measurements were also used to validate numerical simulations of granular systems. It is shown that predictions of time-averaged properties, such as voidage and velocity of the particulate phase, made using the Discrete Element model agree very well with mr measurements.

关键词： Discrete Element modelling magnetic resonance imaging multiscaleGas-fluidized beds rotating cylinders