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mixed convection in the heated semi-circular lid-driven cavity f.r non-Newtonian power-law f.uids: Ef.ect of.presence and shape of.the block

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Chinese Journal of.Chemical Engineering 2020年第5期28卷 1225-1240页

作者： Krunal m.Gangawane Hakan f.Oztop Department of.Chemical Engineering National Institute of Technology RourkelaRourkela 769008OdishaIndia Department of.mechanical Engineering Engineering FacultyFirat UniversityElazig TR-23119Turkey

The present work delineates the hydrodynamics and thermal characteristics due to mixed convection in the liddriven semi-circular cavity af.ected by the presence of.the adiabatic block at its geometric center f.r twodimensional,steady-state,laminar and f.r non-Newtonian power-law *** semi-circular cavity has a diameter of.*** horizontal wall/lid is sliding with a unif.rm horizontal velocity(u=U)and is subjugated to the ambient thermal condition;while the curved surf.ce is subjugated to a higher isothermal *** convective characteristics inside the system is explored f.r the broad range of.Richardson number(0.1≤Ri≤10),Prandtl number(1≤Pr≤100)and non-Newtonian power-law index(0.5≤n≤1.5)at a constant Grashof.number of.10~*** f.om this,the ef.ect of.shape(cross-section)of.the inserted block,i.e.,circular,square and triangular on heat transf.r characteristics has also been *** is observed that the shear thickening f.uids display better cooling ***,the cavity with immersed triangular block shows better heat transf.r results than the circular and square *** deviations observed in the f.ow and heat transf.r characteristics in the cavity by inserting an adiabatic block as compared with cavity without block have been ascertained by calculating normalized Nusselt number(Nu^N).The presence of.the block was f.und to have a diminishing ef.ect on the heat transf.r due to convection in the *** the end,the results of.the study are summarized in the f.rm of.a predictive correlation exhibiting the f.nctional dependence of.average Nusselt number with Prandtl number,power-law index,and Richardson number.

关键词： Heat transf.r enhancement Semi-circular cavity Adiabatic block Non-Newtonian f.uids

Recovery and grade prediction of.pilot plant f.otation column concentrate by a hybrid neural genetic algorithm

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International Journal of.mining Science and Technology 2013年第1期23卷 69-77页

作者： f. Nakhaei m.R. mosavi A. Sam Department of.mining Engineering Shahid Bahonar Kerman University Kerman Iran Department of.Electrical Engineering Iran University of Science and Technology Tehran Iran

Today f.otation column has become an acceptable means of.f.oth f.otation f.r a f.irly broad range of.applications, in particular the cleaning of.sulf.des. Even af.er having been used f.r several years in mineral processing plants, the f.ll potential of.the f.otation column process is still not f.lly exploited. There is no prediction of.process perf.rmance f.r the complete use of.available control capabilities. The on-line estimation of.grade usually requires a signif.cant amount of.work in maintenance and calibration of.on-stream analyzers, in order to maintain good accuracy and high availability. These dif.iculties and the high cost of.investment and maintenance of.these devices have encouraged the approach of.prediction of.metal grade and recovery. In this paper, a new approach has been proposed f.r metallurgical perf.rmance prediction in f.otation columns using Artif.cial Neural Network (ANN). Despite of.the wide range of.applications and f.exibility of.NNs, there is still no general f.amework or procedure through which the appropriate network f.r a specif.c task can be designed. Design and structural optimization of.NNs is still strongly dependent upon the designer's experience. To mitigate this problem, a new method f.r the auto-design of.NNs was used, based on Genetic Algorithm (GA). The new proposed method was evaluated by a case study in pilot plant f.otation column at Sarcheshmeh copper plant. The chemical reagents dosage, f.oth height, air, wash water f.ow rates, gas holdup, Cu grade in the rougher f.ed, f.otation column f.ed, column tail and f.nal concentrate streams were used to the simulation by GANN. In this work, multi-layer NNs with Back Propagation (BP) algorithm with 8-17-10-2 and 8- 13-6-2 arrangements have been applied to predict the Cu and mo grades and recoveries, respectively. The correlation coef.icient (R) values f.r the testing sets f.r Cu and mo grades were 0.93, 0.94 and f.r their recoveries were 0.93, 0.92, respectively. The results disc

关键词： Artif.cial neural network Genetic algorithm f.otation column Grade Recovery Prediction

Comparative study using mS and XRD of.f._(80)Al_(20) alloy produced by mechanical alloying

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Science China(Physics,mechanics & Astronomy) 2013年第8期56卷 1504-1507页

作者： HADEf.f. OTmANI A. GRENèCHE J.m. Laboratoire de Recherche sur la Physico-Chimie des Surf.ces et Interf.ces LRPCSIUniversité 20 Ao t 1955BP 26Route d'El-HaddaiekSkikda 21000Algérie LUNAm Université du MaineInstitut des Molécules et Matériaux du MansIMMM UMR CNRS 628372085 Le MansFrance

An X-ray dif.raction and 57f. mOssbauer ef.ect study of.mechanically alloyed f.80Al20 is presented. X-ray measurements indicate that the disordered bcc α-f.（A1） solid solution was f.rmed af.er 2 h of.milling, while the analysis of.mrssbauer spectra suggested that total dissolution of.aluminium is achieved af.er 10 h of.milling. These dif.erences can be attributed to：（i） rapid nanocrystallization of.aluminium and/or （ii） small particles with small amounts of.aluminium cannot be detected by the X-ray dif.raction technique.

关键词： nanostructured materials f.-AI alloys mechanical alloying X-ray dif.raction m6ssbauer spectrometry

Substrate Strengthening of.CVD Coated Steels

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材料热处理学报 2004年第05B期25卷 791-795页

作者： O. Kessler m. Heidkamp f. Hof.mann P. mayr Stif.ung Institutf.ir Werkstof.technik Bremen GermanyStiftung Institutfiir Werkstofftechnik Bremen GermanyStiftung Institutfiir Werkstofftechnik Bremen GermanyStiftung Institutfiir Werkstofftechnik Bremen Germany

Properties of.components and tools can be improved by the combination of.coating and heat treatment processes due to the addition of.single process advantages and due to the utilization of.process interactions. Several low and high alloyed, structural and tool steels (AISI 4140, 52100, H13, A2, D2, etc.) have been treated by CVD-TiN-coating plus laser beam hardening respectively carburizing plus CVD-TiN-coating. Homogeneous, dense TiN-coatings with high hardness, high compressive residual stresses and good adhesion were supported by high strength substrate surf.ces. Especially CVD plus laser beam hardening of.ers the possibility to reduce distortion due to the small heated surf.ce volume.

关键词： CVD 衬底加强镀层钢板激光束强化渗碳

Resonance Conversion as the Ef.ective Way of.Triggering the ^（178m2）Hf.Isomer Energy

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Chinese Physics Letters 2006年第8期23卷 2049-2051页

作者： f. f.odor KARPESHIN m. B.TRZHASKOVSKAYA 张景波 Science Center and Department of.Physics Harbin Institute of Technology Harbin 150001 f.ck Institute of.Physics St. Petersburg State University RU-198504 St. Petersburg Russia PNPI RU-198355 St. Petersburg Leningrad District Russia

Experiments on photo-induced de-excitation triggering of.^（178m2）Hf.are revisited. We present an alternative and more ef.ective way of.triggering by exploiting the resonance internal conversion. f.ll theoretical description of.a possible channel is presented. It is theref.re revisited the impact itself.produced by those experiments.

关键词： Resonance Conversion Ef.ective Way

State f.edback Tracking Control f.r Indirect f.eld-oriented Induction motor Using f.zzy Approach

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International Journal of.Automation and computing 2013年第2期10卷 99-110页

作者： m. Allouche m. Chaabane m. Souissi D. mehdi f. Tadeo Laboratory of.Sciences and Techniques of.Automatic Control and Computer Engineering (Lab-STA) National School of Engineering of SfaxUniversity of Sfax Laboratory of.Computer and Automatic f.r System (LIAS) Higher School of Engineering of Poitiers (ESIP) University of Poitiers Department of.Systems Engineering University of Valladolid

This paper deals with the synthesis of.f.zzy controller applied to the induction motor with a guaranteed model ref.rence tracking perf.rmance. f.rst, the Takagi-Sugeno （T-S） f.zzy model is used to approximate the nonlinear system in the synchronous d-q f.ame rotating with f.eld-oriented control strategy. Then, a f.zzy state f.edback controller is designed to reduce the tracking error by minimizing the disturbance level. The proposed controller is based on a T-S ref.rence model in which the desired trajectory has been specif.ed. The inaccessible rotor f.ux is estimated by a T-S f.zzy observer. The developed approach f.r the controller design is based on the synthesis of.an augmented f.zzy model which regroups the model of.induction machine, f.zzy observer, and ref.rence model. The gains of.the observer and controller are obtained by solving a set of.linear matrix inequalities （LmIs）. f.nally, simulation and experimental results are given to show the perf.rmance of.the observer-based tracking controller.

关键词： f.zzy tracking control H∞ perf.rmance f.edback controller linear matrix inequality (LmI) f.zzy observer

Boundary-layer non-Newtonian f.ow over vertical plate in porous medium saturated with nanof.uid

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Applied mathematics and mechanics(English Edition) 2011年第12期32卷 1577-1586页

作者： f.m. HADY f. S. IBRAHIm S. m. ABDEL-GAIED m. R. EID Department of.mathematics Faculty of Science Assiut University Assiut 71516 Egypt Department of.Science and mathematics Faculty of Education Assiut University The New Valley 72111 Egypt

The f.ee convective heat transf.r to the power-law non-Newtonian f.ow f.om a vertical plate in a porous medium saturated with nanof.uid under laminar conditions is investigated. It is considered that the non-Newtonian nanof.uid obeys the mathematical model of.power-law. The model used f.r the nanof.uid incorporates the ef.ects of.Brown- ian motion and thermophoresis. The partial dif.erential system governing the problem is transf.rmed into an ordinary system via a usual similarity transf.rmation. The numer- ical solutions of.the resulting ordinary system are obtained. These solutions depend on the power-law index n, Lewis number Le, buoyancy-ratio number Nr, Brownian motion number Nb, and thermophoresis number Nt. f.r various values of.n and Le, the ef.ects of.the inf.uence parameters on the f.uid behavior as well as the reduced Nusselt number are presented and discussed.

关键词： non-Newtonian f.ee convection nanof.uid porous media

High Strain Rate Superplasticity in a micro-grained Al-mg-Sc Alloy with Predominant High Angle Grain Boundaries

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Journal of.materials Science & Technology 2012年第11期28卷 1025-1030页

作者： f. C. Liu Z.Y. ma f. C. Zhang Shenyang National Laboratory f.r materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China State Key Laboratory of.metastable materials Science and Technology Yanshan University Qinhuangdao 066004China

f.iction stir processing （f.P） was applied to extruded AI-mg-Sc alloy to produce f.ne-grained microstructure with a grain size of.2.2μm. Electron backscatter dif.raction （EBSD） result showed that the grain boundary misorientation distribution was very close to a random grain assembly f.r randomly oriented cubes. Super- plastic investigations in the temperature range of.425-500 ℃ and strain rate range of.1x100^-2-1x10 s^-1 showed that a maximum elongation of.1500% was achieved at 475 ℃ and a high strain rate of.1x100^-2-1x10 s^-1. The f.P AI-mg-Sc exhibited enhanced superplastic def.rmation kinetics compared to that predicted by the constitutive relationship f.r superplasticity in f.ne-grained aluminum alloys. The origin f.r enhanced superplas- tic def.rmation kinetics in the f.P alloy can be attributed to its high f.action of.high angle grain boundaries （HAGBs）. The analyses of.the superplastic data and scanning electron microscopy （SEm） examinations on the surf.ces of.def.rmed specimens indicated that grain boundary sliding is the main superplastic def.rmation mechanism f.r the f.P AI-mg-Sc alloy.

关键词： Superplasticity f.iction stir processing Aluminum microstructure f.iction stir welding

PRECIPITATION BEHAVIOR Of.m_(2)N IN A HIGH-NITROGEN AUSTENITIC STAINLESS STEEL DURING ISOTHERmAL AGING

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Acta metallurgica Sinica(English Letters) 2007年第2期20卷 95-101页

作者： f. Shi L.J. Wang W.f. Cui C.m. Liu School of.materials ＆ metallurgy Northeastern UniversityShenyang 110004 China

The precipitation behavior of.m2N and the microstructural evolution in a Cr-mn austenitic stainless steel with a high nitrogen content of.0.43mass% during isothermal aging has been investigated using optical microscopy （ Om）, scanning electron microscopy （SEm）, and transmission electron microscopy （TEm）. The aging treatments have led to the decomposition of.nitrogen supersaturated austenitic matrix through discontinuous cellular precipitation. The precipitated cells comprise alternate lamellae of.m2N precipitate and austenitic matrix. This kind of.precipitate morphology is similar to that of.pearlite. However, owing to the non-eutectoidic mechanism of.the reaction, the growth characteristic of.the cellular precipitates is dif.erent f.om that of.pearlite in f.-C binary alloys. m2N precipitate in the cell possesses a hexagonal crystal structure with the parameters a = 0.4752nm and c = 0.4429nm, and the orientation relationship between the m2V precipitates and austenite determined f.om the SADP is [01^-10]m2N//[101]γ, [2^-1^-10]m2N//[010]γ.

关键词： austenitic stainless steel high nitrogen microstructureisothermal aging precipitation