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Microstructure and dry sliding wear behavior of Cu-Sn alloy reinforced with multiwalled carbon nanotubes

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transactions of Nonferrous Metals Society of China 2016年第7期26卷 1755-1764页

作者： H.M.MALLIkARJUNA k.t.kashyap P.G.kOPPAD C.S.RAMESH R.kESHAVAMURtHY Advanced Composites Research Centre (ACRC) P E S Institute of Technology Department of Mechanical Engineering GEC Department of Mechanical Engineering Atria Institute of Technology Research and Development Rapsri Engineering Products Company Ltd. Department of Mechanical Engineering Alliance College of Engineering and Design Alliance University Department of Mechanical Engineering Dayananda Sagar College of Engineering

Multiwalled carbon nanotubes （MWCNts） reinforced Cu-Sn alloy based nanocomposite was developed by powder metallurgy route. the mass fraction of CNts was varied from 0 to 2% in a step of 0.5%. the developed nanocomposites were subjected to density, hardness, electrical conductivity, and friction and wear tests. the results reveal that the density of nanocomposite decreases with the increase of the mass fraction of CNts. A significant improvement in the hardness is noticed in the nanocomposite with the addition of CNts. the developed nanocomposites show low coefficient of friction and improved wear resistance when compared with unreinforced alloy. At an applied load of 5 N, the coefficient of friction and wear loss of 2%CNts reinforced Cu-Sn alloy nanocomposite decrease by 72% and 68%, respectively, compared with those of Cu-Sn alloy. the wear mechanisms of worn surfaces of the composites are reported. In addition, the electrical conductivity reduces with the increase of the content of CNts.

关键词： Cu-Sn alloy carbon nanotube nanocomposites powder metallurgy microstructure sliding wear

Effect of carbon nanotube and silicon carbide on microstructure and dry sliding wear behavior of copper hybrid nanocomposites

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transactions of Nonferrous Metals Society of China 2016年第12期26卷 3170-3182页

作者： H.M.MALLIkARJUNA C.S.RAMESH P.G.kOPPAD R.kESHAVAMURtHY k.t.kashyap Advanced Composites Research Centre P E S Institute of Technology Department of Mechanical Engineering Government Engineering College Department of Mechanical Engineering Alliance College of Engineering & DesignAlliance University Department of Mechanical Engineering CMR Institute of Technology Department of Mechanical Engineering Dayananda Sagar College of Engineering Department of Mechanical Engineering School of Engineering and TechnologyJain University

Microstructure and tribological properties of copper-based hybrid nanocomposites reinforced with copper coatedmultiwalled carbon nanotubes (MWCNts) and silicon carbide (SiC) were studied. Carbon nanotube was varied from 1% to 4% withsilicon carbide content being fixed at 4%. the synthesis of copper hybrid nanocomposites involves ball milling, cold pressing andsintering followed by hot pressing. the developed hybrid nanocomposites were subjected to density, grain size, and hardness *** tribological performances of the nanocomposites were assessed by carrying out dry sliding wear tests using pin-on-steel disctribometer at different loads. A significant decrease in grain size was observed for the developed hybrid composites when comparedwith pure copper. An improvement of 80% in the micro-hardness of the hybrid nanocomposite has been recorded for 4% carbonnanotubes reinforced hybrid composites when compared with pure copper. An increase in content of CNts in the hybridnanocomposites results in lowering of the friction coefficient and wear rates of hybrid nanocomposites.

关键词： copper carbon nanotubes (CNts) SiC microhardness wear mechanisms nanocomposite

Al-7Si-Mg合金的铸造和热处理参数综述

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有色金属加工 1995年第4期24卷 26-44页

作者： k.t.kashyap 赵宏宇

本文阐述了到目前为止所进行的与 Al-7Si-Mg(重量%)合金的组织和机械性能有关的铸造和热处理参数的研究工作。虽然标准技术推荐有较宽的镁含量范围和相当高的铁含量,但是,为了获得最佳和均匀的机械性能,镁的含量应控制在由要求的性能所... 详细信息

本文阐述了到目前为止所进行的与 Al-7Si-Mg(重量%)合金的组织和机械性能有关的铸造和热处理参数的研究工作。虽然标准技术推荐有较宽的镁含量范围和相当高的铁含量,但是,为了获得最佳和均匀的机械性能,镁的含量应控制在由要求的性能所决定的上限或者下限附近的一个窄范围之内,而且铁的含量也应较低。一些研究揭示出共晶硅的变质作用略微增加合金的延性和断裂韧性,也有认为在低的铁含量情况下,变质作用效果明显。一般地说,较高的凝固速率可得到较好的机械性能。延迟时效(在沉淀硬化情况下,淬火和人工时效之间停留的时间)严重影响合金的强度。延迟时效机制可用 Pashlcy 的动力学模型解释。已有报道认为,某些微量添加剂(镉、铟、锡等)能抑制延迟时效的不利作用。尤其应注意的是,在任何技术标准中都未提及过延迟时效问题。关于微量添加剂对抑制延迟时效的作用机理提出过各种假说。而杂质——空位交互作用显然得到最广泛的认可。

关键词：铝合金铸造热处理参数硅镁含量

Modeling the hot working behavior of near-α titanium alloy IMI 834

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Progress in Natural Science:Materials International 2013年第6期23卷 598-607页

作者： I.Balasundar t.Raghu B.P.kashyap Near Net Shape Group Aeronautical Materials DivisionDefence Metallurgical Research Laboratory Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Bombay

the hot working behavior of near-a titanium alloy IMI 834 with a duplex starting microstructure was studied using the technique of processing *** processing map was interpreted in terms of the microstrucmral processes occurring during deformation,based on the values of dimensionless parameter η which represents the energy dissipation through microstructural *** instability criterion(ξto demarcate the flow instability regions in the processing *** the parameters(η and ξ) were computed using the experimental data generated by carrying out hot compression tests over a range of temperatures(850-1060℃) and strain rates(3×10-1/s).the deterministic domains observed under the investigated temperature and strain rate conditions were attributed to continuous dynamic recrystallization or globularisation of a lamellae,dynamic recrystallization and growth of β grains through microstructural *** unified strain compensated constitutive equation was established to describe the hot working behavior of the material in the selected temperature-strain rate *** established constitutive equation was validated using standard statistical parameters such as correlation coefficient and average absolute relative error.

关键词： titanium alloys IMI 834 Hot working Processing maps Constitutive modeling

Solar Energy Generation Potential Estimation in India and Gujarat, Andhra, telangana States

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Smart Grid and Renewable Energy 2014年第11期5卷 275-289页

作者： t. Harinarayana k. Jaya kashyap Gujarat Energy Research & Management Institute (GERMI) Gandhinagar India Malla Reddy Engineering College Hyderabad India

It is well known that the rampant increase for the demand of electricity and rapid depletion of the fossil fuels has called for immediate response in the direction of energy sufficiency. to accomplish this, one of the important tasks is to identify the locations of high potential for renewable energy generation. It is a well-established fact that solar energy proved to be the most sought after source for energy generation. Although, solar energy potential maps of India have been prepared based on solar irradiation maps in the earlier studies, the present research study has been carried out with a focused attention directly on solar energy generation considering various parameters. In this work it is shown that solar energy generation does not depend on solar radiation alone at a location. Instead, there are various other factors that influence the energy generation. Some of them are ambient temperature, wind velocity and other parameters like weather and topographic conditions. In this study the locations with high and low solar energy generation potential in India have been identified through systematic analysis by computing the solar energy parameters at every grid point (1°× 1°). the work has been extended with more detailed study for Gujarat, Andhra Pradesh and the newly formed telangana states. the data points considered for the states are 0.25°× 0.25°having resulted in adding more number of locations. Our results indicate that the total annual energy generation in India varies from 510,000 kWH to 800,000 kWH per acre of land. the least energy generation location pertains to the eastern parts of Arunachal Pradesh and eastern part of Assam and the highest annual solar energy generation has been identified in the eastern parts of Jammu & kashmir and eastern part of Uttarakhand.

关键词： Solar Energy Estimation Financial Benefits Gujarat Andhra Pradesh telangana India

Optical Spectroscopy of Classical Be Stars in Old Open Clusters

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Research in Astronomy and Astrophysics 2023年第3期23卷 16-24页

作者： Madhu kashyap Jagadeesh Blesson Mathew k.t.Paul Gourav Banerjee Suman Bhattacharyya R.Anusha Pramod kumar S. Department of Physics and Electronics CHRIST(Deemed to be University)Hosur Main RoadBengaluruIndia Department of Physics and Astronomy University of Western OntarioON N6A 3K7Canada Indian Institute of Astrophysics KoramangalaBengaluruIndia

We performed the optical spectroscopy of 16 classical Be stars in 11 open clusters older than 100 *** is the first spectroscopic study of classical Be stars in open clusters older than 100 *** found that the Hαemission strength of most of the stars is less than 40?,in agreement with previous *** analysis further suggests that one of the stars,[kW97]35–12,might be a weak Hαemitter in nature,showing Hαequivalent width of-0.5?.Interestingly,we also found that the newly detected classical Be star LSⅢ+4737b might be a component of the possible visual binary system LSⅢ+4737,where the other companion is also a classical Be ***,the present study indicates the possible detection of a binary Be ***,it is observed that all 16 stars exhibit a lesser number of emission lines compared to classical Be stars younger than 100 ***,the spectral type distribution analysis of B-type and classical Be stars for the selected clusters points out that the existence of CBe stars can depend on the spectral type distribution of B-type stars present in these clusters.

关键词： clusters showing spectroscopic

Photonics bridges between turbulence and spin glass phenomena in the 2021 Nobel Prize in Physics

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Light(Science & Applications) 2022年第5期11卷 743-745页

作者： A.S.L.Gomes C.B.de Araújo A.M.S.Macêdo I.R.R.González L.de S.Menezes P.I.R.Pincheira R.kashyap G.L.Vasconcelos E.P.Raposo Departamento de Física Universidade Federal de PernambucoRecifePE 50670-901Brazil Unidade Acadêmica de Belo Jardim Universidade Federal Rural de PernambucoBelo JardimPEBrazil Chair in Hybrid Nanosystems Nanoinstitut MünchenFakultät für PhysikLudwig-Maximilians-Universität München80539 MünchenGermany Departamento de Ciencias Físicas Universidad de La FronteraTemucoChile Fabulas Laboratory Department of Engineering PhysicsDepartment of Electrical EngineeringPolytechnique MontrealMontreal H3C 3A7 QCCanada Departamento de Física Universidade Federal do ParanáCuritibaPR 81531-990Brazil

A photonic connection between turbulence and spin glasses has been recently established both theoretically and experimentally using a random fiber laser as a photonic *** unveiling this interplay,it links the works of... 详细信息

关键词： fiber turbulence Nobel