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Corrosion behavior of ultrafine-grained AA2024 aluminum alloy produced by cryorolling

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International Journal of Minerals,Metallurgy and Materials 2017年第11期24卷 1293-1305页

作者： P. Laxman Mani kanta v.C. Srivastava k. venkateswarlu sharma Paswan B. Mahato Goutam Das k. Sivaprasad k. Gopala krishna Department of Metallurgical & Materials Engineering National Institute of Technology Thiruchirappalli 620015 India National Metallurgical Laboratory Council of Scientific & Industrial Research Jamshedpur 831007 India National Aerospace Laboratories Council of Scientific & Industrial Research Bangalore 560017 India

The objectives of this study were to produce ultrafine-grained(UFG) AA2024 aluminum alloy by cryorolling followed by aging and to evaluate its corrosion behavior. Solutionized samples were cryorolled to ~85% reduction in thickness. Subsequent aging resulted in a UFG structure with finer precipitates of Al_2CuMg in the cryorolled alloy. The(1) solutionized and(2) solutionized and cryorolled samples were uniformly aged at 160°C/24 h and were designated as CGPA and CRPA, respectively; these samples were subsequently subjected to corrosion studies. Potentiodynamic polarization studies in 3.5 wt% NaCl solution indicated an increase in corrosion potential and a decrease in corrosion current density for CRPA compared to CGPA. In the case of CRPA, electrochemical impedance spectroscopic studies indicated the presence of two complex passive oxide layers with a higher charge transfer resistance and lower mass loss during intergranular corrosion tests. The improved corrosion resistance of CRPA was mainly attributed to its UFG structure, uniform distribution of fine precipitates, and absence of coarse grain-boundary precipitation and associated precipitate-free zones as compared with the CGPA alloy.

关键词： AA2024 alloy cryorolling ultrafine grains precipitation corrosion behavior

Axial variations in anatomical properties and basic density of Eucalypt urograndis hybrid(Eucalyptus grandis × E. urophylla)clones

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Journal of Forestry Research 2015年第3期26卷 739-744页

作者： S. k. sharma S. R. Shukla S. Shashikala v. Sri Poornima Wood Properties and Engineered Wood Division Institute of Wood Science and Technology P.O. MalleswaramBangalore 560 003 India

We studied two clones of Eucalypt urograndis hybrid （Eucalyptus grandis × E. urophylla）, GR283 and GR330, grown in Tumkur district of kamataka （India）, and felled 5-6 years old three trees of each clone. We recorded axial variations in heartwood content, bark properties, wood density and anatomical characteristics of wood in- cluding fibre length, fibre diameter, fibre wall thickness, lumen diameter, vessel frequency, vessel diameter and vessel element length. Clone GR283 had about 10 % heartwood, significantly lower than for clone GR330 （37 %）. Basic wood density along the tree height varied significantly within and between the clones. We observed significant variations in fibre length, fibre diameter and wall thickness within and between the two clones. vessel frequency and vessel element length did not vary but vessel diameter differed significantly between the clones. With a greater proportion of sapwood, clone GR283 can be uti- lized for paper and pulp applications. Clone GR330 had a higher proportion of heartwood and lower wood density and, hence, is more suitable for light-weight material applications.

关键词： Eucalypt urograndis hybrid (Eucalyptusgrandis × E. urophylla) Fibre characteristics - vesselcharacteristics - Wood density Bark density

Recent Advances in Dissecting Stress-Regulatory Crosstalk in Rice

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Molecular Plant 2013年第2期6卷 250-260页

作者： Rita sharma David De vleesschauwer Manoj k. sharma Pamela C. Ronald Department of Plant Pathology and Genome Center University of California Davis CA 95616 USA Joint BioEnergy Institute Emeryville CA 94710 USA Laboratory of Phytopathology Faculty of Bioscience Engineering Ghent University B-9000 Ghent Belgium Department of Plant Molecular Systems Biotechnology and Crop Biotech Institute Kyung Hee University Yongin 446-701 Korea

Biotic and abiotic stresses impose a serious limitation on crop productivity worldwide. Prior or simultaneous exposure to one type of stress often affects the plant response to other stresses, indicating extensive overlap and cross-talk between stress-response signaling pathways. Systems biology approaches that integrate large genomic and prot-eomic data sets have facilitated identification of candidate genes that govern this stress-regulatory crosstalk. Recently, we constructed a yeast two-hybrid map around three rice proteins that control the response to biotic and abiotic stresses, namely the immune receptor XA21, which confers resistance to the Gram-negative bacterium, Xanthomonas oryzae pv. oryzae; NH1, the rice ortholog of NPR1, a key regulator of systemic acquired resistance; and the ethylene-responsive transcription factor, SUBIA, which confers tolerance to submergence stress. These studies coupled with transcriptional profiling and co-expression analyses identified a suite of proteins that are positioned at the interface of biotic and abiotic stress responses, including mitogen-activated protein kinase 5 （OsMPk5）, wall-associated kinase 25 （WAk25）, sucrose non-fermenting-l-related protein kinase-1 （SnRk1）, SUBIA binding protein 23 （SAB23）, and several WRkY family tran- scription factors. Emerging evidence suggests that these genes orchestrate crosstalk between biotic and abiotic stresses through a variety of mechanisms, including regulation of cellular energy homeostasis and modification of synergistic and/or antagonistic interactions between the stress hormones salicylic acid, ethylene, jasmonic acid, and abscisic acid.

关键词： abiotic biotic crosstalk defense response hormone systems biology stress.

Spectroscopic investigations and luminescence spectra of Sm3+ doped soda lime silicate glasses

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Journal of Rare Earths 2009年第5期27卷 773-780页

作者： Y.k. sharma S.S.L. Surana R.k. Singh Department of Physics Govt. Post Graduate College Rudrapur 263153 (U S Nagar) India Department of Physics J. N. V. University Jodhpur-342001 India Department of Physics Govt. Post Graduate College Rudrapur 263153 (U S Nagar) India

Sm3+ doped soda lime silicate glasses co-doped with As2O3 were prepared and characterised by measuring their absorption spectra in Uv-vIS/NIR regions and luminescence spectra in the visible region. Judd-Ofelt intensity parameters, Ωλ, were evaluated from the measured intensities of the various absorption bands. Ωλ parameters of these glasses were compared with the Ωλ parameters of other reported Sm3+ glasses to study the bonding environment surrounding the Sm3+ in the present glasses. Presence of [AsO4]3– tetrahedra in the second coordination sphere around the central Sm3+ ion made these glasses less covalent as compared to other oxide glasses but the ratio Ω4/Ω6 of the 1.83 indicated them to be fairly stable. With the help of Ωλ parameters and luminescence data for various emission lines, radiative properties for different emission lines were calculated. The values of radiative properties indicated that 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions responsible for orange luminescence might be used in the development of materials for LED's and other optical devices in the visible region.

关键词： rare earth glasses Judd-Ofelt theory absorption spectroscopy luminescence

Event-driven flood management:design and computational modules

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Geo-Spatial Information Science 2016年第1期19卷 39-55页

作者： vinod kumar sharma G.Srinivasa Rao E.Amminedu P.v.Nagamani Abhinav Shukla k.Ram Mohan Rao v.Bhanumurthy National Remote Sensing Centre ISRO HyderabadHyderabadTelanganaIndia Department of Geo-Engineering Andhra UniversityVisakhapatnamAndhra PradeshIndia

Flood management is a set of activities that have to be carried out in collaboration with multiple *** flood information with early warning generated using remote sensing satellite technologies can help the agencies to effectively manage the situation on *** environmental parameters and forecasts provided by different agencies can be analyzed and compared with historical flood events for generating probable flood event *** information(environmental parameters)provided by the agencies are heterogeneous and noncompliant to standards and distributed in *** of data from distributed resources and automation of data analysis process for flood management is a primary prerequisite for faster and efficient *** 2.0-based web services enable data creation,sharing,communication,and collaboration on *** data sharing on web 2.0 for making quality of service using open-source software for efficient flood management is a *** software architectures proposed for risk and environmental crisis management are too generic in nature and needs lot of modification for flood *** event-driven model coupled with data standardization procedures using service-oriented architecture provides an effective framework for flood *** this paper,a framework capable of collecting heterogeneous distributed flood-related information for analyzing and alerting probable flood events is *** framework has been implemented to generate automatic flood extent maps,by analyzing the distributed satellite data(as service).The automation of flood delineation process reduces the overall flood product generation ***-source web tools have been utilized in development of spatial information system to visualize and analyze the actual situation on ground facilitating overall decision-making process.

关键词： Flood management software architectures service oriented architecture(SOA) event-based methods automation heterogeneous data

Comparative Analysis of the 100 kb Region Containing the Pi-k^h Locus Between indica and japonica Rice Lines

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Genomics, Proteomics & Bioinformatics 2007年第1期5卷 35-44页

作者： S.P. kumar v. Dalal N.k. Singh T.R. sharma National Research Center on Plant Biotechnology Indian Agriculture Research Institute New Delhi 110112India

We have recently cloned a pathogen inducible blast resistance gene Pi-k^h from the indica rice line Tetep using a positional cloning approach. In this study, we carried out structural organization analysis of the Pi-k^h locus in both indica and japonica rice lines. A 100 kb region containing 50 kb upstream and 50 kb downstream sequences flanking to the Pi-k^h locus was selected for the investigation. A total of 16 genes in indica and 15 genes in japonica were predicted and annotated in this region. The average GC content of indica and japonica genes in this region was 53.15% and 49.3%, respectiveIy. Both indica and japonica sequences were polymorphic for simple sequence repeats having mono-, di-, tri-, tetra-, and pentanucleotides. Sequence analysis of the specific blast resistant Pi-k^h allele of Tetep and the susceptible Pi-k^h allele of the japonica rice line Nipponbare showed differences in the number and distribution of motifs involved in phosphorylation, resulting in the resistance phenotype in Tetep.

关键词： comparative genomics blast resistance gene genome analysis microcolinearity

Effect of Semecarpus anacardium fruits on reproductive function of male albino rats

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Asian Journal of Andrology 2003年第2期5卷 121-124页

作者： Arti sharma Pramod kumar verma v.P.Dixit Department of Zoology Raj Rishi Colloge A/war (Raj) 301001 IndiaReproductive Physiology Section Department of Zoology University of Rajasthan Jaipur-302 004 IndiaReproductive Physiology Section Department of Zoology University of Rajasthan Jaipur-302 004 India

Aim: To evaluate the effect of an ethanolic extract of Semecarpus anacardium fruits on spermatogenesis in albino rats. Methods: Male albino rats were fed with a 50 % ethanolic extract of Semecarpus anacardium fruit at 100 mg·***-1, 200 mg·kg-1·day-1 and 300 mg·kg-1·day-1 for 60 days. Fertility test was performed after 60 days of treatment. Sperm motility and density were observed in the cauda epididymis. Biochemical and histological analyses of the blood and reproductive organs were done. Recovery of fertility was followed to evaluate the reversibility of drug action. Results: S. anacardium fruit extract administration resulted in spermatogenic arrest in albino rats. The sperm motility and density was reduced significantly. The RBC and WBC counts, haemoglobin, haematocrit, blood sugar and urea were found to be within the normal range in the whole blood. The protein, cholesterol and glycogen in the testes and the fructose in the seminal vesicle were significantly decreased after the treatment. The fruit extract feeding caused marked reduction in the number of primary spermatocytes, secondary spermatocytes and spermatids. The number of mature Leydig cells was also decreased and degenerating cells increased proportionately. Conclusion: 5. anacardium fruit extract causes spermatogenic arrest in albino rats.

关键词： Semecarpus anacardium spermatogenesis androgen spermatocytes Leydig cells

NiCo2O4 decorated PANI–CNTs composites as supercapacitive electrode materials

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Journal of Energy Chemistry 2017年第1期26卷 175-181页

作者： Gunjana Chaudhary Ashok k.sharma Preetam Bhardwaj kamal kant Indu kaushal Ajay k.Mishra Thin Film Laboratory Department of Materials Science and NanotechnologyDeenbandhu Chhotu Ram University of Science and TechnologyMurthal 131039India Nanotechnology and Water Sustainability Research Unit College of ScienceUniversity of South AfricaUnisa Science CampusJohannesburgSouth Africa

Hierarchical Ni CoO/PANI/CNTs hybrid composites were designed and fabricated having a layer of Ni CoOon the surface of PANI encapsulated CNTs with different morphologies. Physicochemical attributes of the synthesized composites were examined by FTIR, Uv–visible and X-ray diffraction（XRD）techniques. Morphological aspects were evaluated by field-emission scanning microscopy（FESEM）,electron diffraction spectroscopy（EDS）, high resolution transmission electron microscopy（HRTEM） and selected area electron diffraction（SAED） studies. Electrochemical measurements revealed an improved specific capacitance of 2250 F/g at a scan rate of 5 m v/s and 2000 F/g at a current density of 1 A/g with good rate capability using a three-electrode system. These enhanced features are achieved from the well designed nanostructure and the synergistic contributions of individual components in the electrode material.

关键词： Polyaniline Carbon nanotubes Nickel cobaltite Supercapacitor

Design of high-strength refractory complex solid-solution alloys

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npj Computational Materials 2018年第1期3卷 519-526页

作者： Prashant Singh Aayush sharma A.v.Smirnov Mouhamad S.Diallo Pratik k.Ray Ganesh Balasubramanian Duane D.Johnson Ames Laboratory U.S.Department of EnergyIowa State UniversityAmesIA 50011USA Mechanical Engineering Iowa State UniversityAmesIA 50011USA Materials Science&Engineering Iowa State UniversityAmesIA 50011USA Mechanical Engineering&Mechanics Lehigh UniversityBethlehemPA 18015USA

Nickel-based superalloys and near-equiatomic high-entropy alloys containing molybdenum are known for higher temperature strength and corrosion ***,complex solid-solution alloys offer a huge design space to tune for optimal properties at slightly reduced *** refractory Mo-W-Ta-Ti-Zr,we showcase kkR electronic structure methods via the coherent-potential approximation to identify alloys over five-dimensional design space with improved mechanical properties and necessary global(formation enthalpy)and local(short-range order)*** is modeled with classical molecular dynamic simulations,validated from our first-principle *** predict complex solid-solution alloys of improved stability with greatly enhanced modulus of elasticity(3×at 300 k)over near-equiatomic cases,as validated experimentally,and with higher moduli above 500 k over commercial alloys(2.3×at 2000 k).We also show that optimal complex solid-solution alloys are not described well by classical potentials due to critical electronic effects.

关键词： alloys strength corrosion