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microstructure and tensile properties of friction stir welded dissimilar AA6061-AA5086 aluminium alloy joints

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Transactions of Nonferrous metals Society of China 2015年第4期25卷 1080-1090页

作者： m.ILANGOVAN S.RAJENDRA BOOPATHY V.BALASUBRAmANIAN Department of mechanical Engineering College of Engineering Guindy Anna UniversityChennai India Center for materials Joining & Research Department of Manufacturing Engineering Annamalai UniversityAnnamalai Nagar Chidambaram 608002 Tamilnadu India

The fusion welding of dissimilar heat treatable and non-heat treatable aluminium alloy faced many problems related to solidification. The difficulties can be overcome to achieve the combined beneficial properties of both aluminium alloys using friction stir welding(FSW). The microstructural features and tensile properties of friction stir welded(FSW) similar and dissimilar joints made of AA6061 and AA5086 aluminium alloys were investigated. The microstructures of various regions were observed and analyzed by means of optical and scanning electron microscopy. microhardness was measured at various zones of the welded joints. The tensile properties of the joints were evaluated and correlated with the microstructural features and microhardness values. The dissimilar joint exhibits a maximum hardness of HV 115 and a joint efficiency of 56%. This was attributed to the defect free stir zone formation and grain size strengthening.

关键词： friction stir welding dissimilar joint aluminium alloy microstructure tensile strength

Entropy generation applications in flow of viscoelastic nanofluid past a lubricated disk in presence of nonlinear thermal radiation and Joule heating

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Communications in Theoretical Physics 2021年第9期73卷 37-50页

作者： Aamar Abbasi Waseh Farooq m Ijaz Khan Sami Ullah Khan Yu-ming Chu Zahid Hussain m Y malik Department of mathematics University of Azad Jammu and Kashmir Muzaffarabad13100 Pakistan Department of mathematics and Statistics Riphah International University I-14Islamabad 44000Pakistan Department of mathematics COMSATS University IslamabadSahiwal 57000Pakistan Department of mathematics Huzhou UniversityHuzhou 313000China Department of mathematics College of SciencesKing Khalid UniversityAbha 61413Saudi Arabia

Entropy generation is the loss of energy in thermodynamical systems due to resistive forces,diffusion processes,radiation effects and chemical *** main aim of this research is to address entropy generation due to magnetic field,nonlinear thermal radiation,viscous dissipation,thermal diffusion and nonlinear chemical reaction in the transport of viscoelastic fluid in the vicinity of a stagnation point over a lubricated *** conservation laws of mass and momentum along with the first law of thermodynamics and Fick’s law are used to discuss the flow,heat and mass transfer,while the second law of thermodynamics is used to analyze the entropy and *** numbers of independent variables in the modeled set of nonlinear partial differential equations are reduced using similarity variables and the resulting system is numerically approximated using the Keller box *** effects of thermophoresis,Brownian motion and the magnetic parameter on temperature are presented for lubricated and rough *** local Nusselt and Sherwood numbers are documented for both linear and nonlinear thermal radiation and lubricated and rough *** representations of the entropy generation number and Bejan number for various parameters are also shown for lubricated and rough *** concentration of nanoparticles at the lubricated surface reduces with the magnetic parameter and Brownian *** entropy generation declines for thermophoresis diffusion and Brownian motion when lubrication effects are *** is concluded that both entropy generation and the magnitude of the Bejan number increase in the presence of *** current results present many applications in the lubrication phenomenon,heating processes,cooling of devices,thermal engineering,energy production,extrusion processes etc.

关键词： entropy generation viscoelastic fluid lubricated surface nonlinear thermal radiation Joule heating Keller box method

Potential use of durian fruit(Durio zibenthinus Linn) as an adjunct to treat infertility in polycystic ovarian syndrome

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Journal of Integrative medicine 2016年第1期14卷 22-28页

作者： Reshma m. Ansari Department of Basic medical Sciences Cyberjaya University College of Medical Sciences Cyberjaya 63000 Selangor Malaysia

Infertility due to polycystic ovarian syndrome （PCOS） is a worldwide problem that is increasing at alarming rates. Insulin resistance, the prime factor of PCOS, induces comorbid metabolic syndrome as well. Durian （Durio zibenthinus Linn）, a fruit of Southeast Asia, is used as a natural supplement in healthy diets. This paper is a short literature review that examines the fruit＇s effects against various components of metabolic syndrome and its fertility-enhancing properties in PCOS. Various published literature was reviewed to learn of the anti-inflammatory, anti-oxidant, anti-obesity, anticholesterol, and antihypoglycaemic nature of the fruit. The literature search was done using Pubmed, Google Scholar and library databases. The keywords used were polycystic ovarian syndrome, infertility, metabolic syndrome and Durian zibenthinus Linn. Reviewed studies showed that the fruit is effective against various components of metabolic syndrome, but the mechanisms of action against anovulation and menstrual disturbances in PCOS have yet to be studied. The traditional use of durian as a fertility-enhancing agent needs to be validated scientifically by isolating its various components and ascertaining its fertility enhancing properties.

关键词： Durian zibenthius Linn polycystic ovarian syndrome infertility metabolic syndrome

Experimental Analysis of Atypically Long Finned Oscillating Heat Pipe for Ventilation Waste Heat Recovery Application

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Journal of Thermal Science 2020年第3期29卷 667-675页

作者： mAHAJAN Govinda CHO Heejin SmITH Aaron THOmPSON Scott m. Rheem manufacturing MontgomeryAL 36109USA Department of mechanical Engineering Mississippi State UniversityMsissippi StateMS 39762USA Department of mechanical Engineering Auburn UniversityAubumnAL 36849USA

Oscillating heat pipes(OHP)which are constructed from a serpentine-arranged capillary tube possess a desirable aerodynamic form factor and provide for relatively high heat transfer rates via cyclic evaporation and condensation of an encapsulated working fluid with no internal wicking structure *** last two decades,OHP has been extensively investigated for its potential application in thermal management of various *** study presents an experimental investigation on the heat transfer performance of an atypically long finned *** heat transfer performance of the proposed OHP was analyzed and compared with a bare tube OHP with similar overall *** show that a unit row of finned OHP filled with n-pentane with fill ratio of 70%can recover up to(400±40)W of heat from a typical waste exhaust air *** additional pressure drop due to fins was estimated to be(6.8±2)Pa resulting in an increase of 1–2 W of fan power *** average heat recovery rate via finned OHP was found to be almost 80%more than bare tube OHP filled with same working fluid with same fill ratio.

关键词： oscillating heat pipe waste heat recovery ventilation

Strengthening of aluminium alloy 7005 through imposition of severe plastic deformation supplemented by different ageing treatments

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Transactions of Nonferrous metals Society of China 2021年第10期31卷 2909-2921页

作者： R.BAKHSHI m.H.FARSHIDI S.A.SAJJADI Department of materials Science and metallurgical Engineering Ferdowsi University of MashhadAzadi SquareMashhadIran

Strengthening of aluminium alloys 7xxx through the imposition of severe plastic deformation supplemented by ageing treatments is a challenge due to the limited workability of these alloys in cold deformation *** study aims to comprehensively investigate the strengthening of aluminium alloy 7005 through the imposition of severe plastic deformation supplemented by two different ageing treatments:pre-deformation artificial ageing or postdeformation natural *** this purpose,microstructure evolutions of the alloy processed through mentioned procedures were studied using X-ray diffraction and scanning electron microscopy while the alloy strengthening was evaluated using Vickers hardness *** show that a superlative strengthening is obtained through the imposition of severe plastic deformation supplemented by post-deformation natural *** instance,the yield strength of the alloy increases to more than 400 mPa,about one-third greater than the counterpart amount after the usual T6 *** superlative strength mainly occurs due to refinement of grains,an increase of dislocation density and an increase of volume fraction of the precipitates that appeared during natural *** the applied models,it is inferred that the increase of volume fraction of precipitates that appeared during natural ageing has a determinative role in the strengthening of the alloy.

关键词： severe plastic deformation strength precipitation ageing treatment aluminum alloy 7005

Dry sliding wear characterization of Al 6061/rock dust composite

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Transactions of Nonferrous metals Society of China 2015年第12期25卷 3893-3903页

作者： K.SOORYA PRAKASH A.KANAGARAJ P.m.GOPAL Department of mechanical Engineering Anna University Regional Campus Department of mechanical Engineering Akshaya College of Engineering and Technology

The influence of rock dust size（10-30 μm） and mass fraction（5%-15%） on density, hardness and dry sliding wear behavior of Al 6061/rock dust composite processed through stir casting was investigated. Wear behavior of the developed composite was characterized at different loads, sliding velocities and distances using pin-on-disc setup. The experiments were conducted based on Taguchi＇s L27 orthogonal array and the influence of process parameters on wear rate was studied using ANOVA. The experimental results reveal that the applied load and reinforcement size are the major parameters influencing the specific wear rate for all samples, followed by mass fraction of reinforcement, sliding velocity and sliding distance at the level of 47.61%, 28.57%, 19.04%, 9.52% and 4.76%, respectively. The developed regression equation was tested for its accuracy and made evident that it can be used for predicting the wear rate with minimal error. With the help of SEm images, the worn surfaces of the novel composite were studied and the analysis proves that the wear resistance of aluminium alloys can be well improved with the addition of rock dust as reinforcement.

关键词： aluminium metal matrix composite rock dust stir casting wear ANOVA

Effect of substrate temperature on the physical properties of SnS_2:Cu thin films deposited by spray pyrolysis

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Journal of Semiconductors 2018年第12期39卷 46-51页

作者： m.R.Fadavieslam School of Physics Damghan University

The main impetus of the present study is to investigate thin films of tin disulfide that have been doped with copper impurities and prepared on glass substrates by using the spray pyrolysis technique. Also, the influence of the substrate temperature on the structural, optical, and electrical properties of these films are *** thin films have been characterized by X-ray diffraction(XRD), scanning electron microscopy(SEm), and optical absorption(UV-vis) analyses. The XRD patterns clarify that the thin films possess polycrystalline structures,having a peak associated with the(001) plane of the SnS2 phase. The average crystalline grain sizes were estimated to be within the range 5.7-7.1 nm. The SEm images indicate that the grain size increases from 53 to 114 nm with an increment in the substrate temperature, resulting in an increasing-decreasing trend in the band gap of the thin films. However, the films’ resistance decreases from 92.5 to 0.174 Ω·cm as the substrate temperature increases from 400 to 450 ℃. Also, their optical energy band gap depicts an increasing-decreasing trend with the estimated values of 2.81,3.21, and 3.06 eV at 400, 425, and 450℃, respectively. The thin films exhibit n-type conductivity.

关键词： spray pyrolysis thin film polycrystalline

Hysteresis Loops and Phase Diagrams of the Spin-1 Ising model in a Transverse Crystal Field

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Chinese Physics Letters 2012年第1期29卷 194-197页

作者： S.Bouhou I.Essaoudi A.Ainane m.Saber J.J.de miguel m.Kerouad Laboratoire de Physique des materiaux et modelisations des Systemes Unite Associee au CNRST-URAC 08Department of PhysicsFaculty of SciencesUniversity of Moulay IsmailB.P.11201MeknesMorocco max-Planck-Institut fur Physik Complexer Systeme Nohnitzer Str.38D-01187 DresdenGermany Dpto.Fisica de la materia Condensada C-3 and Institut of Materials Sciences“Nicolas Cabrera”Univ.AutonomaCantoblanco E-28049-MadridSpain

Within the framework of the effective-field theory with a probability distribution technique,which accounts for the self-spin correlation functions,the ferromagnetic spin-1 Ising model with a transverse crystal field on honeycomb,square and simple cubic lattices is *** have investigated the effect of the transverse crystal field on the phase diagrams,magnetization,hysteresis loops and χ_(z,h) of the system.A number of interesting phenomena of the system are discussed.

关键词： transverse Ising crystal

The ASD that Wouldn’t Go Away:An Unusual Case of ASD Device Failure in a Patient with marfan Syndrome

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Congenital Heart Disease 2021年第2期16卷 183-187页

作者： Christopher m.Day Neda mulla Timothy martens Brent m.Gordon Department of Pediatrics Loma Linda University Medical CenterLoma LindaCA 92354USA Division of Pediatric Cardiology Loma Linda University Medical CenterLoma LindaCA 92354USA Division of Cardiothoracic Surgery Loma Linda University Medical CenterLoma LindaCA 92354USA

marfan syndrome patients have connective tissue abnormalities that predispose them to intracardiac defects and postoperative *** present a case of late onset ASD device failure secondary to device movement within the atrial septum in a girl with marfan *** case study suggests that further studies are necessary to determine the optimal device and approach for ASD repair in this patient cohort.

关键词： Congenital heart disease atrial septal defect device closure connective tissue disease marfan syndrome transcatheter intervention