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Microstructures and Mechanical Properties of Vacuum brazed Ti3Al/TiAl joints Using Two Ti-based Filler Metals

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journal of Materials science & Technology 2016年第4期32卷 372-380页

作者： H.s.Ren H.P.Xiong b.Chen s.j.Pang b.Q.Chen L.Ye Department of Material science and Engineering Beihang University Beijing 100191 China Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials Beijing 100095 China

Vacuum brazing of Ti3Al-based alloy to TiAI was firstly carried out by Ti-15Cu-15Ni （wt%） filler metal. A continuous Ti3Al band, Ti2Ni and Ti2Cu/Cu3Ti phases formed and the joint showed a shear strength of 53.8-112.4 MPa at room temperature. For the improvement of the joint strength, a new Ti--Zr--Cu--Ni--Fe filler alloy was designed, and its wettability on Ti3AI and TiA1 substrate was studied with the sessile drop method. After holding for 20 rain at 1010 ℃ the Ti--Zr--Cu--Ni--Fe filler showed a low contact angle of 20° and 21° on Ti3Al and TiAI substrate, respectively. The joint brazed with this novel filler mainly con- sisted of Ti-rich area, Ti3Al reaction layer and residual filler metal. With the increase of the brazing temperature, the amount of residual filler metal decreased and the TisAl reaction layer thickened. The Ti3Al/TiA1 joint brazed with Ti--Zr--Cu--Ni--Fe filler exhibited a lower hardness than that brazed with Ti--Cu--Ni filler. The corresponding joints brazed at 950 ℃ for 5 min presented the shear strength of 257.6± 33.6 MPa at room temperature and 304.8 ± 9.9 MPa at 600 ℃.

关键词： brazingTitanium aluminidesMicrostructureshear strength

soaking Induced Changes in Chemical Composition, Glycemic Index and starch Characteristics of basmati Rice

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Rice science 2015年第5期22卷 227-236页

作者： s.j.KALE s.K.jHA G.K.jHA j.P.sINHA s.b.LAL Division of Food science and Post Harvest Technology Indian Agricultural Research Institute Division of Agricultural Economics Indian Agricultural Research Institute Division of Agricultural Engineering Indian Agricultural Research Institute Division of Computer Applications Indian Agricultural Research Institute

An attempt was made to determine the qualitative changes in basmati rice （Pusa basmati 1121, Pbl121） during soaking at 40 ℃ to 80 ℃. soaking temperature had significant effect （a = 0.01） on chemical composition, glycemic index and starch characteristics of rice. starch content, apparent amylose content, crude protein content and crude fat content in un-soaked rice were found to be 73.24%, 27.26%, 8.79% and 2.56%, respectively, but differences in these traits were observed after soaking. Amylose to amylopectin ratio （Am/Ap） decreased from 0.59 to 0.52 （soaked at 80 ℃）. Crude fibre and crude ash contents increased after soaking. The mineral composition （K, P, s, Ca, Mg, Mn, Fe, Cu and Zn） in soaked rice was found to be 16.46% higher than un-soaked rice at the same degree of polishing. Glycemic index of un-soaked rice was found to be 58.41, but decreased to 54.31 after soaking at 80 ℃. Pasting properties, scanning electron microscope images, and X-ray diffractograms suggested partial gelatinization of starch in the temperature range of 60 ℃ to 80 ℃. based on qualitative changes in rice （apparent amylose content, Am/Ap ratio and crystallinity rate）, it was concluded that intermediate soakincl temperatures （60 ℃ to 70 ℃） would be useful for soaking of Pb1121.

关键词： basmati rice soaking glycemic index starch characteristic temperature chemicalcomposition crystallinity

Nonlinear three-dimensional stretched flow of an Oldroyd-b fluid with convective condition, thermal radiation, and mixed convection

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Applied Mathematics and Mechanics(English Edition) 2017年第7期38卷 969-980页

作者： b. MAHANTHEsH b. j. GIREEsHA s.A. sHEHZAD F.M. AbbAsI R. s. R. GORLA Department of Mathematics Christ University Bangalore 560029 Karnataka India Department of studies and Research in Mathematics Kuvempu University Shankarghatta 577451 Karnataka India Department of Mathematics COMSATS Institute of Information Technology Sahiwal 57000 Pakistan Department of Mathematics COMSATS Institute of Information Technology Islamabad 44000 Pakistan Department of Mechanical and Civil Engineering Purdue University Northwest Indiana 46391 U. S. A

The effect of non-linear convection in a laminar three-dimensional Oldroyd-b fluid flow is addressed. The heat transfer phenomenon is explored by considering the non-linear thermal radiation and heat generation/absorption. The boundary layer as- sumptions are taken into account to govern the mathematical model of the flow analy- sis. some suitable similarity variables are introduced to transform the partial differen- tial equations into ordinary differential systems. fifth-order techniques with the shooting method The Runge-Kutta-Fehlberg fourth- and are used to obtain the solutions of the dimensionless velocities and temperature. The effects of various physical parameters on the fluid velocities and temperature are plotted and examined. A comparison with the exact and homotopy perturbation solutions is made for the viscous fluid case, and an excellent match is noted. The numerical values of the wall shear stresses and the heat transfer rate at the wall are tabulated and investigated. The enhancement in the values of the Deborah number shows a reverse behavior on the liquid velocities. The results show that the temperature and the thermal boundary layer are reduced when the non- linear convection parameter increases. The values of the Nusselt number are higher in the non-linear radiation situation than those in the linear radiation situation.

关键词： nonlinear thermal convection nonlinear thermal radiation Oldroyd-b fluid,convective boundary condition heat source/sink

A comprehensive approach to an equation of state for hard spheres and Lennard jones fluids

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Chinese Physics b 2011年第8期20卷 271-278页

作者： s.b.Khasare 90 New Jagruti Colony Katol Road NagpurIndia

We present a simple method of obtaining various equations of state for hard sphere fluid in a simple unifying way. We will guess equations of state by using suitable axiomatic functional forms （n = 1, 2, 3, 4, 5） for surface tension sn （r）, r≥ d/2 with intermolecular separation r as a variable, where m is an arbitrary real number （pole）. Among the equations of state obtained in this way are Percus-Yevick, scaled particle theory and Carnahan-starling equations of state. In addition, we have found a simple equation of state for the hard sphere fluid in the region that represents the simulation data accurately. It is found that for both hard sphere fluids as well as Lennard-jones fluids, with m = 3/4 the derived equation of state （EOs） gives results which are in good agreement with computer simulation results. Furthermore, this equation of state gives the Percus-Yevick （pressure） EOs for the m = 0, the Carnahan-starling EOs for rn = 4/5, while for the value of m = 1 it corresponds to a scaled particle theory EOs.

关键词： equation of state Lennard-jones potential hard-sphere potential computer algebra,computer simulation

Thermodynamic study of fluid in terms of equation of state containing physical parameters

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Chinese Physics b 2015年第1期24卷 382-387页

作者： s.b.Khasare Department of Physics science College Congress Nagar Nagpur Maharashtra State India

We introduce a simple condition for one mole fluid by considering the thermodynamics of molecules pointing towards the effective potential for the cluster. Efforts are made to estimate new physical parameter f in liquid state using the equation of state containing only two physical parameters such as the hard sphere diameter and binding energy. The temperature dependence of the structural properties and the thermodynamic behavior of the clusters are studied. Computations based on f predict the variation of numbers of particles at the contact point of the molecular cavity（radial distribution function）.From the thermodynamic profile of the fluid, the model results are discussed in terms of the cavity due to the closed surface along with suitable energy. The present calculation is based upon the sample thermodynamic data for n-hexanol, such as the ultrasonic wave, density, volume expansion coefficient, and ratio of specific heat in the liquid state, and it is consistent with the thermodynamic relations containing physical parameters such as size and energy. since the data is restricted to n-hexanol, we avoid giving the physical meaning of f, which is the key parameter studied in the present work.

关键词： equations of state Lenard–jones potential hard-sphere potential

Property enhancement of cast iron used for nuclear casks

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International journal of Minerals,Metallurgy and Materials 2016年第1期23卷 40-48页

作者： R.K. behera b.P. Mahto j.s. Dubey s.C. Mishra s. sen Department of Metallurgical and Materials Engineering National Institute of Technology Rourkela Odisha 769008 India bhaba Atomic Research Centre (Post Irradiation Examination Division) Mumbai 400085 India

Ductile iron （DI） is a preferred material for use in various structural, automotive, and engineering fields because of its excellent combination of strength, toughness, and ductility. In the current investigation, we elucidate the relationship between the morphological and mechanical properties of DI intended for use in safety applications in the nuclear industry. DI specimens with various alloying elements were subjected to annealing and austempering heat treatment processes. A faster cooling rate appeared to increase the nodule count in austempered specimens, compensating for their nodularity value and subsequently decreasing their ductility and impact strength. The ductility and impact energy values of annealed specimens increased with increasing ferrite area fraction and nodularity, whereas an increase in the amounts of Ni and Cr resulted in an increase of hardness via solid solution strengthening. Austempered specimens were observed to be stronger than an- nealed specimens and failed in a somewhat brittle manner characterized by a river pattern, whereas the ductile failure mode was character- ized by the presence of dimples.

关键词： ductile iron nodularity mechanical properties failure modes nuclear industry

Conformable fractional heat equation with fractional translation symmetry in both time and space

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Chinese Physics b 2023年第4期32卷 125-129页

作者： W s Chung A Gungor j Krız b C Lutfuoglu H Hassanabadi Department of Physics and Research Institute of Natural science College of Natural ScienceGyeongsang National UniversityJinju 660-701Korea Mechanical Engineering Akdeniz UniversityAntalyaTurkey Department of Physics University of Hradec KraloveRokitanskeho 6250003 Hradec KraloveCzech Republic Department of Physics Akdeniz UniversityAntalyaTurkey Faculty of Physics Shahrood University of TechnologyShahroodIran

We investigate the fractional heat equation with fractional translation in both time and position with different fractional *** examples,we consider a rod and anα-disk with an initial constant temperature and discuss... 详细信息

关键词： fractional derivative heat equation conformable symmetry

Acoustic stop bands in almost-periodic and weakly randomized stratified media:perturbation analysis

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Acta Mechanica sinica 2008年第5期24卷 549-556页

作者： s.Guenneau A.b.Movchan N.V.Movchan j.Trebicki Department of Mathematical sciences University of LiverpoolPeach StreetLiverpool L69 3BXUK Polish Academy of sciences Institute of Fundamental Technology ResearchSwietokrzyska 21Warsaw 00049Poland

In this paper, we analyze the effect of both deter- ministic and random perturbations of a regular multi-layered elastic structure on its stop band properties. The tool of choice is the transfer matrix method, which is both versatile and easy to implement. In both cases, we find that the stop-bands widen. We observe the appearance of very narrow pass-bands within the stop-bands, which can be observed in other instances in optics.

关键词： Transmission problem small random perturbations stop bands

Voltage regulation in LV grids by coordinated volt-var control strategies

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journal of Modern Power systems and Clean Energy 2014年第4期2卷 319-328页

作者： Miguel jUAMPEREZ Guangya YANG søren bækhøj KjÆR Center for Electric Power and Energy Department of Electrical EngineeringTechnical University of DenmarkElektrovej Building 3252800 Kgs.LyngbyDenmark Danfoss solar Inverters A/s Ulsnæs 16300 Gra°stenDenmark

The increasing penetration level of photovoltaic(PV)power generation in low voltage(LV)networks results in voltage rise issues,particularly at the end of the *** order to mitigate this problem,several strategies,such as grid reinforcement,transformer tap change,demand-side management,active power curtailment,and reactive power optimization methods,show their contribution to voltage support,yet still *** paper proposes a coordinated volt-var control architecture between the LV distribution transformer and solar inverters to optimize the PV power penetration level in a representative LV network in bornholm Island using a multi-objective genetic *** approach is to increase the reactive power contribution of the inverters closest to the transformer during overvoltage *** standard reactive power control concepts,cosu(P)and Q(U),are simulated and compared in terms of network power losses and voltage level along the *** a practical implementation,a reconfigurable hardware is used for developing a testing platform based on real-time measurements to regulate the reactive power *** proposed testing platform has been developed within *** project,which targets to study the approaches for large PV power integration into the network,without the need of reinforcement.

关键词： Voltage regulation Reactive power optimization Genetic algorithm