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Optimization of mechanical and Wear Properties of Functionally Graded Al6061/SiC Nanocomposites Produced by Friction Stir Processing(FSP)

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Acta metallurgica Sinica(English Letters) 2015年第5期28卷 584-590页

作者： m.Saadatmand j.Aghazadeh mohandesi Department of mining and metallurgical Engineering Amir Kabir University of Technology

The objective of present work is to apply the friction stir processing （FSP） to fabricate functionally graded SiC particulate reinforced Al6061 composite and investigate the effect of SiC particle mass fraction distribution on the mechanical properties and wear behavior ofAl6061/SiC composite. Regarding the obtained results in this work, with increasing SiC mass fraction, elongation decreased, but hardness enhanced. However, the optimized functionally graded composite with the highest tensile strength and wear resistance was achieved for composite with 10 wt% surface SiC. Also, the results showed that wear resistance and tensile strength decreased for composite with 13 wt% surface SiC, due to reinforcement particle clustering depending on high SiC mass fraction.

关键词： Functionally graded composite Wear mechanical properties Friction stir processing (FSP)

microstructures in a carburized steel after isothermal pearlitic treatment

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journal of materials Science & Technology 2023年第29期160卷 66-75页

作者： j.Abraham mathews H.Farahani j.Sietsma R.H.Petrov m.G.mecozzi m.j.Santofimia Department of materials Science and Engineering Delft University of TechnologyMekelweg 22628 CDDelftThe Netherlands Tata Steel Research&Development IJmuidenThe Netherlands Department of Electromechanical Systems and Metal EngineeringGhent UniversityTech Lane Ghent Science park-Campus A ZwijnaardeTechnologiepark 46Belgium

The influence of carbon concentration variations on pearlite formation(20 h at 600℃)in a case-carburized steel is *** resultant microstructure shows three distinct regions:carburized case,a transition region,and the original *** microstructural transition from the case to the core regions is observed to be relatively *** investigated region of the carburized case(0.9 wt.%C)con-tains two types of pearlite:ferrite+cementite and ferrite+m_(23)C_(6),where the pearlitic aggregate with m_(23)C_(6)shows faster formation *** kinetics of pearlite formation in the transition region(0.3 wt.%C)is very slow and is observed with only m_(23)C_(6)*** around 40%austenite decomposes into pearlite in the transition region,which,in comparison to the carburized case region of 0.9 wt.%C is a fraction that is lower by a factor of *** is absent in the investigated core region(0.16 wt.%C).The microstructure in this region is predominantly martensite and pro-eutectoid ferrite,with a fraction of ferrite well below the equilibrium *** formation in this region is limited by the redistribution of mainly Ni,mn,and Cr,and their resulting solute drag effect on the austenite/ferrite interface.A ther-modynamic and kinetic argumentation of these observations is provided with the help of thermodynamic data,precipitation simulations,and a general mixed-mode Gibbs energy balance model.

关键词： Pearlite formation Carburized steel m 2_(3)C_(6)carbide Kinetics Solute drag

mg-Al Alloys manufactured by Casting and Hot Working Process

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journal of materials Science & Technology 2008年第1期24卷 96-98页

作者： j.m.Kim j.H.jun W.j.jung Department of Applied materials Eng. Hanbat National University Daejeon 305-719 Korea Light materials Team Korea Institute of Industrial Technology Incheon 406-800 Korea

mechanical properties of mg-Al based alloys at different fabrication state,namely as-cast,hot rolled,and annealed,were investigated to develop the alloys that are suitable for the casting/hot working ***- imental results indicated that the castability such as hot cracking resistance tends to improve with increasing the aluminum ***,the elongation at elevated temperatures was observed to decrease as the AI content increases,implying difficulties in hot forming.A small amount of Zr additions could significantly enhance the room temperature mechanical properties of hot-rolled mg-6%Al-1%Zn *** tendency of remarkable grain coarsening at high temperatures was effectively reduced by the Zr *** analyses suggested that very fine Al-3Zr precipitates formed in the Zr-added alloy are responsible for the obtained results.

关键词： magnesium Casting Forming Tensile properties

New opportunities and challenges in surveying underground cavities using photogrammetric methods

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International journal of mining Science and Technology 2021年第1期31卷 9-13页

作者： malte j.m.Gurgel Axel Preusse Institute for mine Surveying Mining Subsidence Engineering and Geophysics in MiningRWTH Aachen UniversityAachen 52062Germany

The exploitation of the underground is currently undergoing a major transformation *** mining,alternative ways of utilization are playing an increasingly important *** alternative utilizations include the storage of gases,the disposal of radioactive wastes,and the implementation of geothermal storage *** addition,more and more mining operations are being shut down,like the German hard coal mining industry in *** the integrity of closed mines must be ensured in the post-mining *** order to capture such large and complex structures efficiently and reliably,new surveying techniques are required.A promising approach is the use of photogrammetric methods to generate three-dimensional models of the *** is currently known mainly from aerial *** is conceivable to use such methods for underground *** recent years,significant progress has been made in the algorithm-based orientation of unstructured image *** powerful computer systems and the growing range of unmanned aerial vehicles could enable partially automated ***,a number of problems have to be solved for underground imaging *** exposure conditions complicate image ***,the models must be integrated into existing surveying systems with a sufficiently high degree of *** order to consider the numerous technical aspects,the development of an integrated capture and evaluation approach is *** could make an important contribution to the monitoring of critical cavities of different *** an approach would also fit into the current digitization trend in the mining industry and provide new opportunities for ground control in particular.

关键词： Photogrammetry Surveying Subsurface spatial planning

Conforming Hierarchical Basis Functions

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Communications in Computational Physics 2012年第9期12卷 1215-1256页

作者： m.j.Bluck Department of mechanical Engineering Imperial CollegeLondonSW72AZUK

A unified process for the construction of hierarchical conforming bases on a range of element types is proposed based on an ab initio preservation of the underlying *** process supports not only the most common simplicial element types,as are now well known,but is generalized to squares,hexahedra,prisms and importantly *** these latter cases have received(to varying degrees)attention in the literature,their foundation is less well developed than for the simplicial *** generalization discussed in this paper is effected by recourse to basic ideas from algebraic topology(differential forms,homology,cohomology,etc)and as such extends the fundamental theoretical framework established by the work of Hiptmair[16-18]and Arnold et al.[4]for *** process of forming hierarchical bases involves a recursive orthogonalization and it is shown that the resulting finite element mass,quasi-stiffness and composite matrices exhibit exponential or better growth in condition number.

关键词： Finite elements vector basis functions differential forms

Exact solution of Schrdinger equation with q-deformed quantum potentials using Nikiforov–Uvarov method

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Chinese Physics B 2013年第11期22卷 166-173页

作者： Falaye B.j. Oyewumi K.j. Abbas m. Theoretical Physics Section Department of Physics University of Ilorin Physics Department Kebbi State University of Science and Technology

In this paper, we present the exact solution of the one-dimensional Schrrdinger equation for the q-deformed quantum potentials via the Nikiforov-Uvarov method. The eigenvalues and eigenfunctions of these potentials are obtained via this method. The energy equations and the corresponding wave functions for some special cases of these potentials are briefly discussed. The PT-symmetry and Hermiticity for these potentials are also discussed.

关键词： Schrōdinger equation q-deformed quantum potential Woods-Saxon potential Nikiforov-Uvarovmethod

Increase in the Hydrophilicity and Lewis Acid-Base Properties of Solid Surfaces Achieved by Electric Gliding Discharge in Humid Air: Effects on Bacterial Adherence

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Plasma Science and Technology 2009年第2期11卷 187-193页

作者： j.O.KAmGANG m.NAITALI j.-m.HERRY m.-N.BELLON-FONTAINE j.-L.BRISSET R.BRIANDET Laboratory of Interfacial Electrochemistry and Analytical Chemistry University of Rouen INRA(National Institute for Agricultural Research) UMR 763 Bio-adhesion and Hygiene of Materials AgroParisTech UMR 763 Bio-adhesion and Hygiene of Materials AgroParisTech UMR763 Bio-adhesion and Hygiene of Materials

This study addressed the effects of treatment with gliding discharge plasma on the surface properties of solid materials, as well as the consequences concerning adherence of a model bacterium. As evaluated by contact angles with selected liquids, plasma treatment caused an increase in surface hydrophilicity and in the Lewis acid-base components of the surface energy of all materials tested. These modifications were more marked for low density polyethylene and stainless steel than for polytetrafiuoroethylene. After treatment, the hydrophilicity of the materials remained relatively stable for at least 20 days. moreover, analysis of the topography of the materials by atomic force microscopy revealed that the roughness of both polymers was reduced by glidarc plasma treatment. As a result of all these modifications, solid substrates were activated towards micro-organisms and the adherence of S. epidermidis, a negatively charged Lewis-base and mildly hydrophilic strain selected as the model, was increased in almost all the cases tested.

关键词： gliding arc plasma surface energy properties polymers stainless steel surface hydrophilicity atomic force microscopy

Why has canine rabies remained endemic in the Kilosa district of Tanzania? Lessons learnt and the way forward

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Infectious Diseases of Poverty 2015年第1期4卷 88-94页

作者： m.j.Kipanyula Department of Veterinary Anatomy Faculty of Veterinary MedicineSokoine University of AgricultureP.O.Box 3016Chuo KikuuMorogoroTanzania

Background:Domestic dogs are the main targets for rabies control as they are the principal reservoir for transmission of the rabies virus to humans and other domestic *** purpose of this study was to identify the factors that contribute to the rabies virus infecting the human population in a rural community of Eastern ***:Using a cross-sectional study design,field visits were conducted to gather information on villagers’knowledge on and practices associated with canine rabies control and dog vaccination ***:A total of 248 individuals were interviewed in the Kilosa district,*** two-thirds(61.3%)had a primary school *** majority(91.1%)of the respondents were aware that rabies is acquired through dog bites and 66.9%knew about the clinical signs of rabies in an *** few(17.7%),however,were aware of the clinical signs of rabies in *** 20.4%of the respondents knew how rabies is controlled in dogs and 71%were not aware of dog vaccination *** average number of dogs kept per household was 4±3.3;70.0%of the respondents had one to five dogs,28.3%had six to dog dogs,and 1.6%had 16–20 *** dogs were primarily used to guard livestock and property,and to *** 59.7%of the respondents indicated that rabies was a public health *** vaccination coverage was observed in the study area,with previous mass vaccination campaigns covering only 24.4%of the dog *** appeared to have limited value in the studied ***,there were no proper waste disposal facilities and oftentimes wild canids and felids visited the villages to scavenge on kitchen ***:Although communities in the Kilosa district had knowledge on rabies in dogs,they were not aware of the public health implication of the disease,which thus led a poor response during mass dog vaccination *** of a well-coordinated rabies control program,strategic public health awareness camp

关键词： Rabies Zoonotic disease Dog bite Vaccination Kilosa Tanzania

3D kinematicmandiblemodel to designmandibular advancement devices for the treatment of obstructive sleep apnea

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Bio-Design and manufacturing 2021年第1期4卷 22-32页

作者： m.García j.A.Cabrera A.Bataller S.Postigo j.j.Castillo Department of mechanical Engineering University of MálagaC/Doctor Ortiz Ramos s/nAmpliación Campus Teatinos29071 MálagaSpain

mandibular advancement devices(mADs)are one of the treatments used for Obstructive sleep apnea(OSA).mADs try to maintain the mandible in an advanced position to keep the upper airways open when *** achieve this goal,most current mADs limit the mouth opening to a few *** study of the kinematic behaviour of the patient’s jaw is essential in order to design devices that allow greater aperture *** this purpose,a 3D multibody model that reproduces jaw movement has been developed in this *** this end,the movement of the lower incisor has been determined by means of a vision system and reflective *** addition,the kinematics of the temporomandibular joint has been ***,the device is designed and printed using a cam-follower *** way,the cam profiles and the followers are optimally designed and positioned for each patient depending on the physiognomy of the jaw and the opening and advancing movement prescribed by the specialist.

关键词： mandibular advancement device 3D mandible kinematics Cam-follower mechanism 3D printed devices