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Application of shortened heat treatment cycles on A356 automotive brake calipers with respective globular and dendritic microstructures

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Transactions of Nonferrous Metals Society of China 2010年第9期20卷 1780-1785页

作者： H.MLLER G.GOVEN DER W.E.STUMPF Materials Science and Manufacturing Council for Scientific and Industrial Research (CSIR) Department of Materials Science and Metallurgic al Engineering University of Pretoria

Since the automotive industry has many possible applications for semi-solid metal (SSM)-high-pressure die casting (HPDC) parts, the newly developed heat treatment cycles, as well as the traditional heat treatment cycles, were applied to A356 brake calipers cast using a LK DCC630 HPDC *** hardness measurements at a cross section of the brake calipers were performed, indicating that similar values can be obtained when using the significantly shorter heat treatment ***, the typical tensile properties that can be obtained for SSM-HPDC A356 brake calipers are compared with those manufactured by gravity die *** indicate that the differences in microstructures (globular or dendritic) do not have a noteworthy effect on the heat treatment *** implies that the short heat treatment cycles originally developed for globular SSM-HPDC A356 castings can be successfully applied to dendritic liquid A356 castings too.

关键词： semi-solid metal (SSM) forming heat treatment A356 brake caliper gravity die casting automotive

Low Pressure DC Glow Discharge Air Plasma Surface Treatment of Polyethylene (PE) Film for Improvement of Adhesive Properties

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Plasma Science and Technology 2013年第1期15卷 56-63页

作者： Krishnasamy NAVANEETHA PANDIYARAJ Vengatasamy SELVARAJAN Rajendrasing R. DESHMUKH Coimbatore. Paramasivam YOGANAND Suresh BALASUBRAMANIAN Sundaram MARUTHAMUTHU Department of Physics Sri Shakthi Institute of Engineering and Technology Plasma Physics Laboratory Department of Physics Bharathiar University Department of Physics Institute of Chemical Technology Microbial-Corrosion Laboratory Central Electrochemical Research Institute

The present work deals with the change in surface properties of polyethylene （PE） film using DC low pressure glow discharge air plasma and makes it useful for technical applications. The change in hydrophilicity of the modified PE film surface was investigated by measuring contact angle and surface energy as a function of exposure time. Changes in the morphological and chemical composition of PE films were analyzed by atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. The improvement in adhesion was studied by measuring T-peel and lap-shear strength. The results show that the wettability and surface energy of the PE film has been improved due to the introduction of oxygen-containing polar groups and an increase in surface roughness. The XPS result clearly shows the increase in concentration of oxygen content and the formation of polar groups on the polymer surface. The AFM observation on PE film shows that the roughness of the surface increased due to plasma treatment. The above morphological and chemical changes enhanced the adhesive properties of the PE＇film surfaces, which was confirmed by T-peel and lap-shear tests.

关键词： glow discharge plasma PE hydrophilicity XPS and adhesion

Enhancement of figure of merit（ZT） by doping Bi in Mg2Si for energy harvesting applications

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Progress in Natural Science:Materials International 2016年第6期26卷 533-539页

作者： Kulwinder Kaur Ranjan Kumar Department of Physics Panjab University

Magnesium Silicide is one of the interesting thermoelectric materials known for relative abundance of its constituents, thermal stability, non-toxicity and environmental friendly nature. In this paper we have theoretically studied Bi doped Mg2Si. The electronic structure calculations predict non-existence of the energy gap for Mg2Si1-xBixwith（0.125≤ x≤0.5）. It has been found that the system with x=0.125 exhibits highest Seebeck coefficient and electrical conductivity. Due to low thermal conductivity at x=0.125, Mg2Si0.875Bi0.125attained maximum value of dimensionless figure of merit 0.67 at 1200 K. With increase in concentration of Bi,the value of figure of merit decreases.

关键词： Electrical transport properties Thermoelectric properties Carrier concentration Density functional theory Lattice thermal conductivity Electronic structure

Solvent-free aerobic oxidation of ethylbenzene over supported Ni catalysts using molecular oxygen at atmospheric pressure

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Journal of Natural Gas Chemistry 2008年第3期17卷 293-297页

作者： G.Raju P.Shiva Reddy J.Ashok B.Mahipal Reddy A.Venugopal Catalysis & Physical Chemistry Division Indian Institute of Chemical Technology

We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation of ethylbenzene activities was measured in a round bottom flask immersed in oil bath at known reaction temperature. The physicochemical characteristics of the catalysts were examined by BET surface area, XRD, FT-IR and the oxidation activities were correlated with the acidities of the catalysts obtained by TPD of NH3. It was observed that both hydroxyapatite and USY （13% Na2O） supported Ni catalysts displayed higher ethylbenzene conversion and 80% selectivity towards acetophenone.

关键词： nickel SBA-15 zeolites hydroxyapatite ethylbenzene oxidation TPD of NH3

Property mapping of polycrystalline diamond coatings over large area

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Journal of Advanced Ceramics 2014年第1期3卷 56-70页

作者： Awadesh Kumar MALLIK Sandip BYSAKH Monjoy SREEMANY Sudakshina ROY Jiten GHOSH Soumyendu ROY Joana Catarina MENDES Jose GRACIO Someswar DATTA CSIR-Central Glass&Ceramic research Institute Kolkata 700032West BengalIndia Department of Physics Indian Institute of Technology BombayPowaiMumbai 400076MaharashtraIndia Instituto de Telecomunicações Campus Universitário de Santiago3810-193Portugal Nanotechnology research Division Centre for Mechanical Technology and AutomationUniversity of Aveiro3810-193Portugal

Large-area polycrystalline diamond(PCD)coatings are important for fields such as thermal management,optical windows,tribological moving mechanical assemblies,harsh chemical environments,biological sensors,*** plasma chemical vapor deposition(MPCVD)is a standard technique to grow high-quality PCD films over large area due to the absence of contact between the reactive species and the filament or the chamber ***,the existence of temperature gradients during growth may compromise the desired uniformity of the final diamond *** the present work,a thick PCD coating was deposited on a 100-mm silicon substrate inside a 915-MHz reactor;the temperature gradient resulted in a non-uniform diamond *** attempt was made to relate the local temperature variation during deposition and the different properties of the final *** was found that there was large instability inside the system,in terms of substrate temperature(as high asΔT=212℃),that resulted in a large dispersion of the diamond coating’s final properties:residual stress(-15.8 GPa to+6.2 GPa),surface morphology(octahedral pyramids with(111)planes to cubo-octahedrals with(100)flat top surfaces),thickness(190μm to 245μm),columnar growth of diamond(with appearance of variety of nanostructures),nucleation side hardness(17 GPa to 48 GPa),quality(Raman peak FWHM varying from 5.1 cm^(-1) to 12.4 cm^(-1) with occasional splitting).This random variation in properties over large-area PCD coating may hamper reproducible diamond growth for any meaningful technological application.

关键词： plasma-enhanced chemical vapor deposition(CVD) diamond film mechanical properties nanostructures

Nanomaterials Synthesis and Effect of Granular Disorders on Electrical Behavior of Lanthanum Manganites

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Journal of Materials Science & Technology 2011年第8期27卷 691-695页

作者： Avneesh Anshul S.S. Amritphale Sarabjeet Kaur Renu Hada Advanced Materials & Processes research Institute (CSIR) Hoshangabad Road

Comprehensive investigation on the synthesis and electrical transport behaviors of polycrystalline samples of lanthanum manganite due to static disorder was reported. The process parameters were optimized for different batches to yield variable grain sizes. Different sintering conditions and technique like thermal cycling were employed to obtain better grain packing density. The liquid nitrogen and air quenching of the samples were carried out to restrict the grain growth with well defused grain boundary. Variable grain habits and sizes were synthesized by standard solid-state reaction and modified sol-gel synthesis routes. Large variation of grain size, connectivity and packing was observed by varying sintering temperature and synthesis technique. The process dependent grain sizes were observed in the wide range from 20 nm to 1.5 μm by transmission and scanning electron microscopy, The variations in residual resistivity as well as metal-insulator transitions are observed. The observed data were analyzed on the basis of contributions from various dynamic interactions and static disorders.

关键词： Order-disorder effect Sintering Manganites

Integrated transcriptome interactome study of oncogenes and tumor suppressor genes in breast cancer

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Genes & Diseases 2019年第1期6卷 78-87页

作者： G.Pranavathiyani Raja Rajeswary Thanmalagan Naorem Leimarembi Devi Amouda Venkatesan Centre for Bioinformatics School of Life SciencesPondicherry UniversityPondicherry 605014India

Breast cancer is the leading cause for mortality among women *** of oncogenes and tumor suppressor genes is the major reason for the cause of *** these genes will provide clues and insights about their regulatory mechanism and their interplay in *** the present study,an attempt is made to compare the functional characteristics and interactions of oncogenes and tumor suppressor genes to understand their biological role.431 breast cancer samples from seven publicly available microarray datasets were collected and analysed using GEO2R *** identified 416 differentially expressed genes were classified into five gene sets as oncogenes(OG),tumor suppressor genes(TSG),druggable genes,essential genes and other *** gene sets were subjected to various analysis such as enrichment analysis(viz.,GO,Pathways,Diseases and Drugs),network analysis,calculation of mutation frequencies and Guanine-Cytosine(GC)*** the results,it was observed that the OG were having high GC content as well as high interactions than ***,the OG are found to have frequent mutations than *** enrichment analysis results suggest that the oncogenes are involved in positive regulation of cellular protein metabolic process,macromolecule biosynthetic process and majorly in cell cycle and focal adhesion pathway in *** was also found that these oncogenes are involved in other diseases such as skin diseases and viral ***,paclitaxel and docetaxel are some of the drugs found to be enriched for oncogenes.

关键词： Breast cancer Differential gene expression Network analysis Oncogenes Tumor suppressor genes

Propagation of Rayleigh waves on free surface of transversely isotropic generalized thermoelastic diffusion

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Applied Mathematics and Mechanics(English Edition) 2008年第11期29卷 1451-1462页

作者： Rajneesh Kumar Tarun Kansal Department of Mathematics Kurukshetra UniversityKurukshetra-136 119India

The present paper is devoted to the study of Rayleigh wave propagation in a homogeneous, transversely isotropic, thermoelastic diffusive half-space, subject to stress free, thermally insulated/isothermal, and chemical potential boundary conditions in the context of the generalized thermoelastic diffusion theory. The Green-Lindsay（GL） theory is used in the study. In this theory, thermodiffusion and thermodiffusion mechanical relaxations are governed by four different time constants. Secular equations for surface wave propagation in the considered media are derived. Anisotropy and diffusion effects on the phase velocity, attenuation coefficient are graphically presented in order to present the analytical results and make comparison. Some special cases of frequency equations are derived from the present investigation.

关键词： wave propagation transversely isotropic generalized thermoelastic diffusion phase velocity attenuation coefficient

Physico-chemical and elemental investigation of aqueous leaching of high sulfur coal and mine overburden from Ledo coalfield of Northeast India

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International Journal of Coal Science & Technology 2018年第3期5卷 265-281页

作者： Madhulika Dutta Puja Khare Sanchita Chakravarty Durlov Saikia Binoy K. Saikia Polymer Petroleum and Coal Chemistry Group Materials Sciences and Technology Division CSIR-North East Institute of Science and Technology Jorhat 785006 India School of Applied Sciences Department of Chemistry University of Science and TechnologyRibhoi 793101 Meghalaya India Department of Chemistry CNB College Bokakhat 785612India Agrotechnology Division CSIR- Central Institute of Medicinal and Aromatic Plants Lucknow 226015 India Analytical Chemistry Division CSIR- National Metallurgical Laboratory Jamshedpur 831007 India

Acid mine drainage （AMD） is one of the major problems in high sulfur coal mining areas generating acidic water. The acidic mine water generated contain hazardous elements in varying concentrations. The Northeastern Indian coalfield produces considerable amounts of AMD. The AMD and metal leaching from coal and mine over burden （OB） are the two important naturally occurring processes. In order to know the AMD potential, the aqueous leaching experiment of a few coal and OB samples from the Ledo colliery of the Northeastern coalfield, Mergherita （India）, at different time periods （1, 3, 5, and 8 h） and at different temperatures （25, 45, 65, and 90℃） were performed in the laboratory. The physico- chemical analysis of the aqueous leachates shows the pH, electrical conductivity （EC）, and total dissolved solid （TDS） in the range of 1.62-3.52, 106-2006 μs/cm, and 106-1003 ppm for the raw coal samples respectively. The OB samples produced pH, EC, and TDS in the range of 3.68-6.92, 48.6-480 μs/cm, and 69.5-240 ppm respectively. From the study, it was revealed that the concentrations of major （Si, A1, K, Na, Fe, Ca, Mg）, minor （Mn） and trace/hazardous elements （As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Zn） considerably change with leaching time as well as with leaching temperature. Out of these elements As, Cd, Hg, Pb, Cr, and Se are of greater environmental importance. Alteration of the physico-chemical structure of the coal and OB samples resulting from leaching was also studied by field emission scanning electron microscope- energy-dispersive X-ray spectroscopy method. The release of the potentially hazardous elements from the raw coal and OB during leaching time periods to the leachates was detected by inductively coupled plasma-atomic emission spectroscopy and ion-chromatographic analyses. The major minerals found in coal and OB are quartz （SiO2）, pyrite （FeS2）, hematite, marcasite, and kaolinite. The association of different functional groups in minerals and their mode of a

关键词： AMD High sulfur coal Coal mine overburden Aqueous leaching Elements in coal and OB Coal qualityassessment