检索结果-南通市图书馆

Effects of SiC Nanoparticle Content on the microstructure and Tensile mechanical Properties of Ultrafine Grained AA6063-SiC_(np) Nanocomposites Fabricated by Powder metallurgy

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2017年第9期33卷 1023-1030页

作者： X.Yao z.zhang Y.F.zheng C.Kong m.z.Quadir J.m.liang Y.H.Chen P.munroe D.L.zhang State Key Laboratory of metal matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong University Electron microscope Unit University of New South Wales School of materials Science and Engineering University of New South Wales

Ultrafine grained AA6063-SiCnpnanocomposites with 1, 5 and 10 vol.% SiCnphave been fabricated by a novel powder metallurgy process. This process combines high energy ball milling of a mixture of 6063 alloy granules made from machining chips and Si C nanoparticles and thermomechanical powder consolidation by spark plasma sintering and hot extrusion. The microstructure and tensile mechanical properties of the samples were investigated in detail. Increasing the Si C nanoparticle content from 1 to 10 vol.%,the yield strength and ultimate tensile strength increased from 296 and 343 mPa to 545 and 603 mPa respectively, and the elongation to fracture decreased from 10.0%, to 2.3%. As expected, a higher Si C nanoparticle content generates a stronger inhibiting effect to grain growth during the thermomechanical powder consolidation process. Analysis of the contributions of various strengthening mechanisms shows that a higher Si C nanoparticle content leads to a higher contribution from nanoparticle strengthening, but grain boundary strengthening still makes the largest contribution to the strength of the *** the Si C nanoparticle content increased to 10 vol.%, the failure of the nanocomposite was initiated at weakly-bonded interparticle boundaries(IPBs), indicating that with a high flow stress during tensile deformation, the failure of the material is more sensitive to the presence of weakly-bonded IPBs.

关键词： metal matrix nanocomposite Ultrafine grained material Powder metallurgy Tensile mechanical properties

The Effect of Non-Contact Conditions in a Splinted Fixed Partial Denture on the Load Sharing mechanism： A Finite Element Study

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2012年第3期9卷 336-342页

作者： m. z. Bendjaballah Biomedical Technology Department College of Applied Medical Sciences King Saud University Riyadh Saudi Arabia

A computer-aided design model for a fixed partial denture was constructed and used in a finite element analysis to study the overall load sharing mechanism between the fixed partial denture and oral structures while the denture base rested on the al- veolar ridge. To investigate the consequences of non-contact conditions, three additional models were generated incorporating a uniform clearance of 0.125 mm, 0.25 mm, and 0.5 mm, respectively. A 100 N static load located at the free end of the prosthesis was applied while the distal portion of the jaw was set fixed. The results show that whilst releasing the ridge almost entirely, the presence of the clearance drastically increased the load on the splinting teeth. A pull-out force on the canine tooth of about 44 N was computed, accompanied by a mesio-distal moment of about 500 ***. The combination of which was similar to the tooth extraction maneuver performed by the dentist. In contrast, the second premolar was found to bear a push-in force of almost 115 N. The first molar, though barely solicited in the contact condition, became substantially loaded in non-contact conditions, which validates the choice of sacrificing three teeth to support the denture.

关键词： finite element analysis splinted fixed partial denture hygienic space load transfer mechanism contact problem

In vitro Ruminal Gas Production Kinetics of Four Fodder Trees Ensiled With or Without molasses and Urea

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2013年第7期12卷 1234-1242页

作者： Abdelfattah z m Salem zHOU Chuan-she TAN zhi-liang miguel mellado moises Cipriano Salazar mona m m Y Elghandopur Nicholas E Odongo Faculty of Veterinary and Livestock Autonomous University of the State of Mexico Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Department of Animal Nutrition Autonomous Agrarian University Antonio Narro Faculty of Veterinary and Livestock Autonomous University of Guerrero

This study investigated if the addition of urea （U）, molasses （m） or their 1：1 （v/v） mixture during ensiling increases the nutritional value of forage from four fodder trees （Prunus persica, Leucaena esculenta, Acacia farnesiana, and Prunus domestica）. Forage samples of fodder trees were collected in triplicate （three individual samples of each species） and subjected to an in vitro gas production （GP） procedure. Fermentation at 24 h （GP 24）, short-chain volatile fatty acids （SCFA）, and microbial crude protein production （mCP）, in vitro organic matter digestibility （OmD）, metabolizable energy （mE） and dry matter degradability （DmD） were estimated. Forage samples were incubated for 72 h in an incubator at 39oC and the volume of GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48, and 72 h of incubation using the reading pressure technique. The rumen fermentation profiles were highest for P. persica, which showed the highest （P〈0.0001） DmD, mE, OmD, SCFA, GP 24 and mCP. On the other hand L. esculenta had the lowest （P〈0.0001） DmD, SCFA, mCP; P. domestica had the lowest （P〈0.0001） OmD. The addition of m to silage increased （P〈0.0001） mE and OmD, as well as GP. However, the addition of U and the mixture of U and m reduced （P〈0.0001） DmD, mE, OmD, SCFA, GY 24 and mCP. These results show that P. persica has the highest nutritive value and L. esculenta the lowest for ruminants. Additionally, the addition of m to forage from fodder trees increases rumen GP and fermentation, which may improve nutrient utilization in ruminants.

关键词： fodder trees urea molasses gas production

Fire hazard in transportation infrastructure:Review,assessment,and mitigation strategies

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2021年第1期15卷 46-60页

作者： Venkatesh KODUR m.z.NASER Department of Civil and Environmental Engineering Michigan State UniversityEast LansingMI 48824-1226USA Glenn Department of Civil Engineering Clemson UniversityClemsonSC 29634USA

This paper reviews the fire problem in critical transportation infrastructures such as bridges and *** magnitude of the fire problem is illustrated,and the recent increase in fire problems in bridges and tunnels is *** research undertaken to address fire problems in transportation structures is reviewed,as well as critical factors governing the performance of those ***,key strategies recommended for mitigating fire hazards in bridges and tunnels are presented,and their applicability to practical situations is demonstrated through a practical case ***,research needs and emerging trends for enhancing the“state-of-the-art”in this area are discussed.

关键词： fire hazard bridges tunnels fire resistance mitigation strategies transportation infrastructure

Production of porous silica by the combustion of rice husk ash for tundish lining

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2008年第3期15卷 307-313页

作者： Y.m.z.Ahmed E.m.Ewais z.I.zaki Central metallurgical Research and Development Institute(CmRDI)

In order to study the production of porous silica compacts by the combustion of rice husk ash （RHA） for tundish lining, the experimental design technique was used to evaluate the effect of firing temperature, soaking time and compaction pressure on controlling both the porosity degree and compressive strength of rice husk ash compacts. The results revealed that while the porosity degree of the compacts decreased with the increase in the entire studied parameters, the compressive strength exhibited another trend especially at a lower soaking time. At a lower soaking time, the increase in firing temperature led to a slight decrease in compressive strength and then increasing thereafter. The porous silica compacts having 30% porosity and 〉 2.5 mPa compressive strength suitable for tundish lining could be obtained from the combustion of rice husk ash compacts.

关键词： porous silica rice husk ash tundish lining compressive strength porosity

Large Eddy Simulation of Flow over a Cylinder Using High-Order Spectral Difference method

在线全文

学校读者我要写书评

暂无评论

Advances in Applied mathematics and mechanics 2010年第4期2卷 451-466页

作者： Abrar H.mohammad z.J.Wang Chunlei liang Department of Aerospace Engineering Iowa State UniversityAmesIA 50011U.S.A Department of Aeronautics and Astronautics Stanford UniversityStanfordCA 94305U.S.A

Large eddy simulation of the flow over a circular cylinder at Reynolds number ReD=2580 has been studied with a high-order unstructured spectral difference *** and polynomial refinement studies were carried out to assess numerical *** mean and fluctuating velocity fields in the wake of a circular cylinder were compared with PIV experimental *** numerical results are in excellent agreement with the experimental data for both the mean velocity and Reynolds stresses using the high-order SD *** wake characteristics such as the recirculation bubble length,vortex formation length and maximum intensity of the velocity fluctuations have also been predicted *** numerical simulations demonstrated the potential of the high-order SD method in accurate large eddy simulation of physically complex problems.

关键词： LES spectral difference circular cylinder coherent structures vortex shedding

A theoretical study on different cluster configurations of the ~9Be nucleus by using a simple cluster model

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2017年第6期28卷 179-189页

作者： m.Aygun z.Aygun Department of Physics Bitlis Eren University Vocational School of Technical Sciences Bitlis Eren University

In this study,a comprehensive investigation on different cluster configurations of the ~9Be nucleus is performed with a simple cluster *** this goal,the elastic scattering angular distributions of ~9Be by ^(27)A1,^(28)Si,^(64)zn,^(144)Sm,^(208)Pb,and ^(209)Bi target nuclei are reanalyzed for α + α + n,d + ~7Li,~3H + ~6Li,~3He + ~6He and n + ~8Be cluster configurations of the ~9Be projectile within the framework of the optical *** theoretical results are compared with each other as well as the experimental *** results provide an opportunity for a test of different cluster configurations in explaining the elastic scattering of^9Be nucleus.

关键词： Cluster structure Optical model Double folding model Elastic scattering

Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2024年第2期45卷 373-388页

作者： m.RAHmAN m.TURKYILmAzOGLU z.mUSHTAQ Department of mathematics Mirpur University of Science and TechnologyMirpur 10250Pakistan Department of mathematics Hacettepe UniversityBeytepeAnkara 06532Turkiye

In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating *** steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is *** shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are *** shape exists in the same volume of a *** leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity *** system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4c mATLAB *** outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower *** the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom *** ranges of various parameters taken into account are Pr=6.2,Re=2,m=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.

关键词： transformer oil Brinkman number skin friction coefficient double rotating disk Nusselt number Sherwood number

Flow of Eyring-Powell liquid due to oscillatory stretchable curved sheet with modified Fourier and Fick’s model

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2021年第10期42卷 1461-1478页

作者： m.ImRAN z.ABBAS m.NAVEED Department of mathematics The Islamia University of BahawalpurBahawalpur 63100Pakistan Department of mathematics Khwaja Fareed University of Engineering&Information TechnologyRahim Yar Khan 64200Pakistan

This study deals with the features of the mass and heat transport mechanism by adopting a modified version of Fourier and Fick’s model known as the CattaneoChristov double diffusive *** time-dependent magnetohydrodynamic(mHD)flow of the Eyring-Powell liquid across an oscillatory stretchable curved sheet in the presence of Fourier and Fick’s model is *** acquired set of flow equations is transformed into the form of nonlinear partial differential equations(PDEs)by applying appropriate similarity variables.A convergent series solution to the developed nonlinear equations is accomplished with the help of an analytical approach,i.e.,the homotopy analysis method(HAm).The consequences of diverse parameters,including the dimensionless EyringPowell liquid parameter,the radius of curvature,the Schmidt/Prandtl numbers,the ratio of the oscillatory frequency of the sheet to its stretchable rate constant,the mass and thermal relaxation variables involved in the flow,and the heat and mass properties,are displayed through graphs and *** is noted from this study that the amplitude of the pressure distribution rises for the high parametric values of the Eyring-Powell parameter.

关键词： oscillatory stretchable curved surface magnetohydrodynamic(mHD) Eyring-Powell liquid Cattaneo-Christov double diffusion analytical technique