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Combined heat and mass transfer by mixed convection MHD flow along a porous plate with chemical reaction in presence of heat source

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Applied Mathematics and Mechanics(English Edition) 2010年第10期31卷 1217-1230页

作者： j.ZUECO s.AHMED ETs Ingeniería Industrial Departamento de Ingeniería Térmicay FluidosUniversidad Politécnica de Cartagena Fluid Dynamics Research Department of MathematicsGoalpara College

An exact and a numerical solutions to the problem of a steady mixed convective MHD flow of an incompressible viscous electrically conducting fluid past an infinite vertical porous plate with combined heat and mass transfer are presented.A uniform magnetic field is assumed to be applied transversely to the direction of the flow with the consideration of the induced magnetic field with viscous and magnetic dissipations of *** porous plate is subjected to a constant suction velocity as well as a uniform mixed stream *** governing equations are solved by the perturbation technique and a numerical *** analytical expressions for the velocity field,the temperature field,the induced magnetic field,the skin-friction,and the rate of heat transfer at the plate are *** numerical results are demonstrated graphically for various values of the parameters involved in the *** effects of the Hartmann number,the chemical reaction parameter,the magnetic Prandtl number,and the other parameters involved in the velocity field,the temperature field,the concentration field,and the induced magnetic field from the plate to the fluid are *** increase in the heat source/sink or the Eckert number is found to strongly enhance the fluid velocity *** induced magnetic field along the x-direction increases with the increase in the Hartmann number,the magnetic Prandtl number,the heat source/sink,and the viscous *** is found that the flow velocity,the fluid temperature,and the induced magnetic field decrease with the increase in the destructive chemical *** of the study arise in the thermal plasma reactor modelling,the electromagnetic induction,the magnetohydrodynamic transport phenomena in chromatographic systems,and the magnetic field control of materials processing.

关键词： MHD perturbation technique network simulation method Eckert number mixed convection induced magnetic field viscous dissipation heat source/sink

Evaluation of the virulence of entomopathogenic fungus, Isaria fumosorosea isolates against subterranean termites Coptotermes spp.(Isoptera:Rhinotermitidae)

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journal of Forestry Research 2019年第1期30卷 213-218页

作者： j.j.jessica T.L.Peng A.s.sajap s.H.Lee s.A.syazwan Department of Forest Management Faculty of ForestryUniversiti Putra Malaysia (UPM) Faculty of Veterinary Medicine University Malaysia Kelantan Institute of Tropical Forestry and Forest Products Universiti Putra Malaysia (UPM) Mycology and Pathology Laboratory Forest Biodiversity Division Forest Research Institute Malaysia

The entomopathogenic fungus Isaria fumosorosea Wize, formerly known as Paecilomyces fumosoroseus is reported as a promising biocontrol agent for controlling subterranean termites, particularly those belonging to the family Rhinotermitidae. In Malaysia, the family Rhinotermitidae includes two species of subterranean termites with extremely high economic importance; namely Coptotermes curvignathus Holmgren, and the Asian sLubterranean Termite (Coptotermes gestroi Wasmann). To comprehend the potential control of this soil-dwelling fungus against these subterranean termites in Malaysia, an investigation was carried out by testing the pathogenecity of 11 isolates against these termite species. All isolates showed pathogenic potential against the termite (Mortality rate of C. curvignathus:84.4%; C. gestroi:67.3%). IsolatePF49 was the most effective against both species of termites and was further tested for its virulence and *** LC_(50) values of PF49 against C. curvignathus and *** were 7.55×103 and 1.09×102 conidia/ml,respectively. The average number of days required to complete the mycosis process in C. curvignathus and *** were 4.7 and 8 days, respectively. These fungi are believed useful for protecting living trees, plants, wood,wood structures, and other cellulosic materials susceptible to termite infestation and damage.

关键词： Biological control Entomopathogenic fungus subterranean termites Lethal concentration

Effects of welding parameters and post-heat treatment on mechanical properties of friction stir welded AA2195-T8 Al-Li alloy

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journal of Materials science & Technology 2018年第1期34卷 219-227页

作者： j. Zhang X.s. Feng j.s. Gao H. Huang Z.Q. Ma L.j. Guo Technical Center Shanghai Aerospace Equipments Manufacturer Shanghai 200245. China

In this study, the effects of main welding parameters （rotation speed （ω） and welding speed （υ）） on the microstructure, micro-hardness distribution and tensile properties of friction stir welded （FsW） 2195-T8 Al-Li alloy were investigated. The effects of T6 post-treatments at different solution and aging conditions on the mechanical properties and microstructure characteristics of the FsW joints were also investigated. The results show that with increasing to and v, both strength and elongation of the joints increase first, and then decrease with further increase of ω and υ. All the joints under varied welding parameters show significant strength loss, and the strength reaches only 65% of the base metal, The effect of T6 post-heat treatment on the mechanical properties of the joints depends on the solution and aging conditions. Two heat treatment processes （480 ℃×0.5 h quenching＋ 180 ℃× 12 h, 520 ℃× 0.5 h quenching＋ 180 ℃×12h aging） are found to increase the joint strength. Furthermore, low temperature quenching （480℃） is more beneficial to the joint strength. The joint strength can reach 85% of the base metal. Whereas both low temperature aging （140 ℃× 56h） and stepped aging （ 100 ℃× 12 h ＋ 180 ℃× 3 h） processes decrease the joint strength. After heat treatment all the joints show decreased ductility due to the obvious grain coarsening in the nugget zone （NZ） and thermo-mechanically affected zone （TMAZ）.

关键词： 2195-T8 Al-Li alloy Friction stir welding Welding parameters Post-heat treatment

A nanostructured copper telluride thin film grown at room temperature by an electrodeposition method

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journal of semiconductors 2012年第9期33卷 22-27页

作者： s.s.Dhasade s.H.Han V.j.Fulari Holography and Material Research Laboratatory Department of PhysicsShivaji UniversityKolhapur 416004India Department of Chemistry Hanyang UniversitySouth Korea

Copper telluride onion flower like microstructures, constructed by quantum dots with various diameters, were obtained by a potentiostatic electrodeposition method at room temperature. The structural, optical, surface morphology, compositional analysis and Raman spectra properties of the deposited films have been studied using X-ray diffraction, optical absorption with scanning electron microscopy, EDAX, and Raman spectroscopy, The electrolyte concentration and deposition time can be used to control the diameter of the electrodeposited quantum dots to within a range of 50-55 nm. The films are found to be stoichiometric in composition. The optical constants such as the optical band gap energy and the optical absorption spectra show significant variation in their values with a change in deposition time. Upon deposition time the band gap energy increased from a value of 2.74 to 2.89 eV.

关键词： electrodeposition copper telluride quantum dots chemical composition optical properties

Deformation behavior of laser bending of circular sheet metal

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Chinese Optics Letters 2011年第5期9卷 47-51页

作者： Q.Nadeem s.j.Na Department of Mechanical Engineering KAIST

The application of a thermal source in non-contact forming of sheet metal has long been used. However, the replacement of this thermal source with a laser beam promises much greater controllability of the process. This yields a process with strong potential for application in aerospace, shipbuilding, automobile, and manufacturing industries, as well as the rapid manufacturing of prototypes and adjustment of misaligned components. Forming is made possible through laser-induced non-uniform thermal stresses. In this letter, we use the geometrical transition from rectangular to circle-shaped specimen and ring-shaped specimen to observe the effect of geometry on deformation in laser forming. We conduct a series of experiments on a wide range of specimen geometries. The reasons for this behavior are also analyzed. Experimental results are compared with simulated values using the software ABAQUs. The utilization of line energy is found to be higher in the case of laser forming along linear irradiation than along curved ones. We also analyze the effect of strain hindrance. The findings of the study may be useful for the inverse problem, which involves acquiring the process parameters for a known target shape of a wide range of complex shape geometries.

关键词： Deformation behavior of laser bending of circular sheet metal

REAL CODED GENETIC ALGORITHM FOR sTOCHAsTIC HYDROTHERMAL GENERATION sCHEDULING

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journal of systems science and systems Engineering 2011年第1期20卷 87-109页

作者： jarnail s.DHILLON j.s.DHILLON D.P.KOTHARI G.Z.s.College of Engineering and Technology sant Longowal Institute of Engineering and Technology Vindhya Institute of Technology and science

The intent of this paper is to schedule short-term hydrothermal system probabilistically considering stochastic operating cost curves for thermal power generation units and uncertainties in load demand and reservoir water inflows. Therefore, the stochastic multi-objective hydrothermal generation scheduling problem is formulated with explicit recognition of uncertainties in the system production cost coefficients and system load, which are treated as random variable. Fuzzy methodology has been exploited for solving a decision making problem involving multiplicity of objectives and selection criterion for best compromised solution. A real-coded genetic algorithm with arithmetic-average-bound-blend crossover and wavelet mutation operator is applied to solve short-term variable-head hydrothermal scheduling problem. Initial feasible solution has been obtained by implementing the random heuristic search. The search is performed within the operating generation limits. Equality constraints that satisfy the demand during each time interval are considered by introducing a slack thermal generating unit for each time interval. Whereas the equality constraint which satisfies the consumption of available water to its full extent for the whole scheduling period is considered by introducing slack hydro generating unit for a particular time interval. Operating limit violation by slack hydro and slack thermal generating unit is taken care using exterior penalty method. The effectiveness of the proposed method is demonstrated on two sample systems.

关键词： stochastic multi-objective optimization real-coded genetic algorithm fuzzy set economicload dispatch

Analysis of antisym metric cross-ply laminates using high-order shear deformation theories:a meshless approach

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Acta Mechanica sinica 2020年第5期36卷 1078-1098,I0003页

作者： D.E.s.Rodrigues j.Belinha L.M.j.s.Dinis R.M.Natal jorge Institute of science and Innovation in Mechanical and Industrial Engineering 4200-465 PortoPortugal Department of Mechanical Engineering School of EngineeringPolytechnic of Porto(ISEP)4200-072 PortoPortugal Department of Mechanical Engineering Faculty of EngineeringUniversity of Porto(FEUP)4200-465 PortoPortugal

For many years finite element method(FEM)was the chosen numerical method for the analysis of composite ***,in the last 20 years,the scientific community has witnessed the birth and development of several meshless methods,which are more flexible and equally accurate numerical *** meshless method used in this work is the natural neighbour radial point interpolation method(NNRPIM).In order to discretize the problem domain,the NNRPIM only requires an unstructured nodal ***,using the Voronoi mathematical concept,it enforces the nodal connectivity and constructs the background integration *** NNRPIM shape functions are constructed using the radial point interpolation *** this work,the displacement field of composite laminated plates is defined by high-order shear deformation *** the end,several antisymmetric cross-ply laminates were analysed and the NNRPIM solutions were compared with the *** obtained results show the efficiency and accuracy of the NNRPIM formulation.

关键词： Antisymmetric cross-ply laminates High-order shear deformation theories Meshless methods Naturalneighbour radial point interpolation method(NNRPIM)

Use of silica nanopowder to accelerate CO_2 sorption by Ca(OH)_2

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Particuology 2013年第4期11卷 448-453页

作者： M.A.s.Quintanilla j.M.Valverde Faculty of Physics University of SevilleAvenida Reina Mercedes s/n

Promising technologies have recently emerged to capture CO2 from postcombustion flue gas and to enhance the production of hydrogen from natural gas by steam-methane reforming, on the basis of sorp- tion of CO2 by Ca-based powders. The rate of CO2 sorption on Ca-based powders is limited by both carbonation kinetics and transport of CO2 to unreacted sorption sites. Ca-based powders may exhibit cohesive aggregation, thus hindering gas-solids contact efficiency. In our work, we tested the sorption rate of powder samples prepared by dry mixing of a cohesive Ca（OH）2 powder with a silica nanopowder used as additive. The silica nanopowder serves to improve the dispersibility of Ca（OH）2. Consequently, when a CO2 enriched gas and the modified sorbent are brought into contact, the rate of CO2 sorption is enhanced in the initial fast phase of interest for practical applications.

关键词： FluidizationFine powdersCO2 sorptionNanoparticles

Effect of wood dust type on mechanical properties, wear behavior, biodegradability, and resistance to natural weathering of wood-plastic composites

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Frontiers of structural and Civil Engineering 2019年第6期13卷 1446-1462页

作者： sawan KUMAR Ajitanshu VEDRTNAM s.j.PAWAR Department of Applied Mechanics Motilal Nehru National Institute of Technology AllahabadAllahabadUP 211004India Department of Mechanical Engineering Invertis UniversityBareillyUP 243001India Vinoba Bhave Research Institute AllahabadUP 211004India Translational Research Centre Institute of Advanced MaterialsVBRIL inkoping 58330Sweden

The present work reports the inclusion of different proportions of Mango/sheesham/Mahogany/Babool dust to polypropylene for improving mechanical,wear behavior and biodegradability of wood-plastic composite(WPC).The wood dust(10%,15%,20%by weight)was mixed with polypropylene granules and WPCs were prepared using an injection molding *** mechanical,wear,and morphological characterizations of fabricated WPCs were carried out using standard AsTM methods,pin on disk apparatus,and scanning electron microscopy(sEM),***,the biodegradability and resistance to natural weathering of WPCs were evaluated following AsTM D5338-11 and AsTM D1435-99,*** WPCs consisting ofBabool and sheesham dust were having superior mechanical properties whereas the WPCs consisting of Mango and Mahogany were more wear *** was found that increasing wood powder proportion results in higher Young's modulus,lesser wear rate,and decreased stress at *** WPCs made of sheesham dust were least *** was noticed that the biodegradability corresponds with resistance to natural weathering;more biodegradable WPCs were having the lesser resistance to natural weathering.

关键词： wood-plastic composites mechanical testing wear biodegradability injection molding weathering