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Transition States for Shock Induced Chemical Reactions in Binary Energetic Materials

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Journal of Materials Science and Chemical Engineering 2020年第7期8卷 27-35页

作者： Vindhya narayanan Sathya Hanagud Georgia Institute of Technology Atlanta GA USA

In this paper, numerical simulation of shock induced chemical reactions of a thermite mixture of binary energetic material, aluminum and iron oxide, are discussed. To initiate the chemical reactions, the impact or the shockwave should supply the energy to take the reactants, aluminum and iron oxide, to the transition state. Thus, for any numerical simulation of the shock or impact induced chemical reaction in a continuum or mesoscale, it is necessary to identify the transition state. The transition state for the thermite mixture, of aluminum and iron oxide, is identified in this paper and a result from a numerical simulation of the shock induced chemical reaction, in a continuum scale is presented.

关键词： Numerical Simulation Chemical Reaction

Simulated Annealing Algorithm to Minimize Makespanin Single Machine Scheduling Problem withUniform Parallel Machines

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Intelligent Information Management 2011年第1期3卷 22-31页

作者： Panneerselvam Senthilkumar Sockalingam narayanan 不详

This paper presents a simulated annealing algorithm to minimize makespan of single machine scheduling problem with uniform parallel machines. The single machine scheduling problem with uniform parallel machines consists of n jobs, each with single operation, which are to be scheduled on m parallel machines with different speeds. Since, this scheduling problem is a combinatorial problem;usage of a heuristic is inevitable to obtain the solution in polynomial time. In this paper, simulated annealing algorithm is presented. In the first phase, a seed generation algorithm is given. Then, it is followed by three variations of the simulated annealing algorithms and their comparison using ANOVA in terms of their solutions on makespan.

关键词： Uniform Parallel Machines Measure of Performance Heuristic Simulated Annealing Algorithm ANOVA

Ce-SAD Phasing of Glucose Isomerase and Thermolysin Using Cu <i>Kα</i>Radiation

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Crystal Structure Theory and Applications 2013年第3期2卷 93-99页

作者： Sibi narayanan Devadasan Velmurugan Centre of Advanced Study in Crystallography and Biophysics University of Madras Maraimalai (Guindy) Campus Chennai India

Current structural genomics projects aim to solve a large number of selected protein structures as fast as possible. High degree of automation and standardization is required at every step of the whole process to speed up protein structure determination. Phase problem is a bottleneck in macromolecular structure determination and also in model building which is a time-consuming task. The simplest approach to phasing macromolecular crystal structures is the use of a SAD signal. SAD data can be collected using the in-house copper (1.54 A) wavelength source. Data collected using copper wavelength with the incorporation of anomalously scattering heavy metal atoms may serve as a powerful tool for structural biologists to solve novel protein structures as well where synchrotron beam line is not available. A short soak of protein crystals in heavy metal solution or by incorporating heavy atoms into the protein drop while crystallizing the protein (co-crystallization) leads to incorporation of these heavy metal ions into the ordered solvent shell around the protein surface. The present work aims to determine whether cerium ion can be successfully incorporated into the protein crystal through quick-soaking method while maintaining the isomorphism. The study also aims in understanding whether this metal ion can be used for phasing purpose. The intensity data are collected and analyzed for anomalous signal, substructure solution and the binding sites.

关键词： Anomalous Scattering SAD phasing Ce Glucose Isomerase Thermolysin

Lab Source Anomalous Scattering Using Cr Kα Radiation

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Crystal Structure Theory and Applications 2013年第2期2卷 57-64页

作者： Sibi narayanan Devadasan Velmurugan Centre of Advanced Study in Crystallography and Biophysics University of Madras Maraimalai (Guindy) Campus Chennai India

High-throughput crystallography requires a method by which the structures of proteins can be determined quickly and easily. Experimental phasing is an essential technique in determining the three-dimensional protein structures using single-crystal X-ray diffraction. In macromolecular crystallography, the phases are derived either by Molecular Replacement (MR) method using the atomic coordinates of a structurally similar protein or by locating the positions of heavy atoms that are intrinsic to the protein or that have been added (MIR, MIRAS, SIR, SIRAS, MAD and SAD). Availability of in-house lab data collection sources (Cu Kα and Cr Kα radiation), cryo-crystallography and improved software for heavy atom location and density modification have increased the ability to solve protein structures using SAD. SAD phasing using intrinsic anomalous scatterers like sulfur, chlorine, calcium, manganese and zinc, which are already present in the protein becomes increasingly attractive owing to the advanced phasing methods. An analysis of successful SAD phasing on three proteins, lysozyme, glucose isomerase and thermolysin based on the signal of weak anomalous scatterers such as sulfur atom and chloride ion have been carried out. This analysis also proves that even the anomalous signal provided or present naturally in a macromolecule is good enough to solve crystal structures successfully using lab source chromium-generated X-ray radiation.

关键词： Anomalous Scattering SAD Phasing Lysozyme Glucose Isomerase Thermolysin

Enhancing Lab Source Anomalous Scattering Using Cr Kα Radiation for Its Potential Application in Determining Macromolecular Structures

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Crystal Structure Theory and Applications 2012年第3期1卷 84-91页

作者： Sibi narayanan Devadasan Velmurugan Centre of Advanced Study in Crystallography and Biophysics University of Madras Maraimalai (Guindy) Campus Chennai India

Obtaining phase information for the solution of macromolecular structures is a bottleneck in X-ray crystallography. Anomalous dispersion was recognized as a powerful tool for phasing macromolecular structures. It was used mainly to supplement the isomorphous replacement or to locate the anomalous scatterer itself. The first step in solving macromolecular structures by SAD (single-wavelength anomalous diffraction) is the location of the anomalous scatterers. The SAD method for experimental phasing has evolved substantially in the recent years. A phasing tool, 5-amino-2,4,6- triiodoisophthalic acid (I3C—magic triangle), was incorporated into three proteins, lysozyme, glucose isomerase and thermolysin using quick-soaking and co-crystallization method in order to understand the binding of metal ion with proteins. The high quality of the diffraction data, the use of chromium anode X-ray radiation and the required amount of anomalous signal enabled way for successful structure determination and automated model building. An analysis and/or comparison of the sulfur and iodine anomalous signals at the Cr Kα wavelength are discussed.

关键词： Anomalous Scattering SAD Phasing I3C Lysozyme Glucose Isomerase Thermolysin

On the Growth Mechanism of Nickel and Cobalt Nanowires and Comparison of Their Magnetic Properties

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Nano Research 2008年第6期1卷 465-473页

作者： T.N.narayanan M.M.Shaijumon Lijie Ci P.M.Ajayan M.R.Anantharaman Department of Physics Cochin University of Science&TechnologyCochin-22KeralaIndia Department of Mechanical Engineering&Materials Science Rice UniversityHoustonTX 77005USA

Magnetic nanowires(NWs)are ideal materials for the fabrication of various multifunctional nanostructures which can be manipulated by an external magnetic fi *** crystalline and textured nanowires of nickel(Ni NWs)and cobalt(Co NWs)with high aspect ratio(~330)and high coercivity have been synthesized by electrodeposition using nickel sulphate hexahydrate(NiSO_(4)·6H_(2)O)and cobalt sulphate heptahydrate(CoSO_(4)·7H_(2)O)respectively on nanoporous alumina *** exhibit a preferential growth along〈110〉.A general mobility assisted growth mechanism for the formation of Ni and Co NWs is *** role of the hydration layer on the resulting one-dimensional geometry in the case of potentiostatic electrodeposition is verified.A very high interwire interaction resulting from magnetostatic dipolar interactions between the nanowires is *** unusual low-temperature magnetisation switching for fi eld parallel to the wire axis is evident from the peculiar high fi eld M(T)curve.

关键词： Magnetic nanowires mobility assisted growth magnetostatic interaction electrodeposition magnetisation switching

Effect of surface mechanical attrition treatment of titanium using alumina balls： surface roughness, contact angle and apatite forming ability

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Frontiers of Materials Science 2013年第3期7卷 285-294页

作者： M. JAMESH T. S. N. SANKARA narayanan Paul K. CHU II Song PARK Min Ho LEE National Metallurgical Laboratory Madras Centre CSIR Madras Complex Taramani Chennai 600 113 India Department of Physics and Material Science City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong China School of Physics University of Sydney NSW 2006 Australia Department of Dental Biomaterials School of Dentistry Chonbuk National University Jeonju 561-756 South Korea

The effect of surface mechanical attrition treatment （SMAT） of commercially pure titanium （CP-Ti） using 8 mm O alumina balls was studied. SMAT induced plastic deformation, increased the surface roughness, reduced the grain size and decreased the contact angle （from 64° to 43°） with a corresponding increase in surface energy （from 32 to 53 mJ/m2）. Untreated CP-Ti and those treateded using alumina bails for 900 s reveals no apatite growth until the 28th day of immersion whereas those treated for 1800 and 2700 s exhibit apatite growth In selective areas and the extent of growth is increased with increase in immersion time an SBF; The study reveals that SMAT using alumina balls is beneficial in imparting the desired surface Cheracteristics, provided the surface contamination is limited, which would otherwise decrease the apatite forming ability.

关键词： KEYWORDS: nanostructured material surface modification sca.ning electron micro-scopy (SEM) surface mechanical attrition treatment(SMAT)

Analytical Solutions of Nonlinear Differential Equations in the Mathematical Model for Inactivation of Nitric Oxide by Rat Cerebellar Slices

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American Journal of Analytical Chemistry 2014年第14期5卷 908-919页

作者： narayanan Mehala Lakshmanan Rajendran Department of Mathematics K.L.N. College of Engineering Sivagangai India Department of Mathematics The Madura College Madurai India

A mathematical model for the inactivation of nitric oxide by rat cerebellar slices under non-steady state condition has been analyzed. This diffusion-inactivation model was used to estimate the kinetics of NO consumption by the rat cerebellar slices. He’s Homotopy perturbation method is used to solve the first order nonlinear differential equations which describe the concentrations given by net of diffusion and inactivation by the slices. Analytical expressions for the concentration of nitric oxide have been derived for all values of parameters. The obtained analytical results are compared with the simulation results (Matlab/Scilab program) and are found to be in good agreement.

关键词： Cyclic Guanosine Monophosphate (CGMP) Inactivation Mathematical Modeling Nitric Oxide Rat Cerebellar Slices

Phoenix phylogeny, and analysis of genetic variation in a diverse collection of date palm(Phoenix dactylifera) and related species

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Plant Diversity 2019年第5期41卷 330-339页

作者： Srinivasa R.Chaluvadi Porter Young Kentrez Thompson Bochra Amina Bahri Bhavesh Gajera Subhash narayanan Robert Krueger Jeffrey L.Bennetzen Department of Genetics University of GeorgiaAthensGAUSA Institute of Plant Breeding Genetics and Genomics(Department of Crop and Soil Sciences)and Department of Plant BiologyUniversity of GeorgiaAthensGA 30602USA Laboratory of Bioaggressors and Integrated Protection in Agriculture The National Agronomic Institute of TunisiaUniversity of Carthage43 Avenue Charles-NicolleTunis 1082Tunisia Anand Agricultural University AnandIndia USDA-ARS National Clonal Germplasm Repository for Citrus and Dates RiversideCAUSA

Date palm(Phoenix dactylifera),one of the most ancient crops,is grown commercially in>30 *** whole plastome assemblies,phylogenetic analyses revealed that cultivated date palm accessions share the same clade with Phoenix sylvestris,Phoenix pusilla and Phoenix acaulis,which are native to the Indian subcontinent,and Phoenix caespitosa that is native to the Arabian Peninsula and the deserts of *** of genetic diversity and genetic relationships among date palm accessions from 13 producing countries involved 195 date palm accessions that were genotyped at 19 microsatellite *** genetic diversity was observed,with many accessions heterozygous for most markers in this clonally propagated *** average number of alleles per locus(42.1),expected heterozygosity(0.8),observed heterozygosity(0.47)and fixation indices(FST=0.42)demonstrated substantial genetic diversity and population *** accessions were found to have the richest allelic diversity,and the most private *** model-based Bayesian method indicated that these accessions could be broadly divided into two structure groups,one group with predominantly African accessions and another predominantly *** germplasm,especially from Tunisia and Iraq,deviated from this *** accessions in the STRUCTURE-derived groups were found to be genetic admixtures,with gene flow between Asian and African *** and Pakistani date palms were found to be most closely related to North African germplasm.

关键词： Date palm improvement Germplasm dissemination Plastome Simple sequence repeats