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Luminescence Dating and Bra.k.ting Time of the Youngest Toba Tuff Deposits in the Quaternary Sediments of Purna Alluvial Basin,Central India

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Journal of Earth Science 2022年第4期33卷 1007-1016页

作者： Singh Ajab k.srivastava Ashok Chauhan Naveen Department of Geology Faculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Department of Geology SGB Amravati UniversityAmravati 444602India Physical Research Laboratory Ahmedabad 380009India

Light gray to yellowish brown youngest Toba tuff(YTT)ash,preserved in the Quaternary sediments of India,have been used as a tool to know depositional and bra.k.ting time period of the same in the sediments through applications of luminescence dating to interpret age connotation of various geological ***-and post-tephra sediments of YTT ash beds from Hudki and Sukali areas of Purna alluvial basin,Central India have been optically dated to interpret the depositional age and bra.k.ting time of the tephra within sedimentary *** sediments are yellowish brown,thinly bedded,laminated,silty clay and host laterally extend discontinued beds of 0.15–0.20 m *** ash is light gray,fine grained and powdery in nature,massive to structureless and la.k. any sign of retransportation and redeposition,hence,considered as primary in *** four sediment samples,one each from pre-and post-tephra lithounits of both the localities have been dated through optically stimulated luminescence technique(OSL)equipped with single aliquot regenerative(SAR)procedure on the feldspar *** shows pre-and post-tephra ages of 57±5 and 70±4 ka respectively for Hudki and 66±5 and 67±4 ka for Sukali *** depositional ages suggest that the ash was bra.k.ted within sediments thousands years after YTT *** is correlatable with the previously reported depositional and absolute ages for the YTT ash from the localities of Ghoghara and khuntheli,Son Valley;Tejpur,Madhumati River Basin and Jwalapuram,Jurreru *** ages also provide an idea about the period of existence of biological communities represented by the remains of faunal and vegetational activities before and during settlement of the YTT ash in the basin area.

关键词： youngest Toba tuff Tephra optically stimulated luminescence Quaternary sediments depositional age

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THEORY OF INTERPOLATION ON INFINITE INTERVAL—Ⅰ(UNIFORM CONVERGENCE OF STABLE INTERPOLATION PROCESSES)

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Acta Mathematica Scientia 1986年第4期6卷 373-378页

作者： k.B.srivastava Department of Mathematics Indian Institute of Technology kanpur-208016 India

§1. Preliminaries and Results Let us begin by defining a triangular matrix L whose n-th row consists of n distinct points xvn, v=1, n; n=1, 2, … such that 01n2n<…nn<∞. （1.1） Denote by H_n.（f, x, L）≡H_n（f, L... 详细信息

关键词： THEORY OF INTERPOLATION ON INFINITE INTERVAL UNIFORM CONVERGENCE OF STABLE INTERPOLATION PROCESSES

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Microstructure transformations and improving wear resistance of austenitic stainless steel additively fabricated by arc-based DED process

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Defence Technology（防务技术） 2024年第8期38卷 194-204页

作者： Ashish Yadav Manu srivastava Prashant k.Jain Sandeep Rathee Hybrid Additive Manufacturing Laboratory Mechanical Engineering DepartmentPDPM Indian Institute of Information TechnologyDesign&ManufacturingJabalpur482005Madhya PradeshIndia FFF Laboratory Mechanical Engineering DepartmentPDPM Indian Institute of Information TechnologyDesign&ManufacturingJabalpur482005Madhya PradeshIndia Department of Mechanical Engineering National Institute of TechnologySrinagarIndia

In this study, austenitic stainless steel(ASS) was additively fabricated by an arc-based direct energy deposition(DED) technique. Macrostructure, microstructure, mechanical characteristics at different spatial orientations(0°, 90°, and 45°), and wear characteristics were evaluated at the deposited structure top, middle, and bottom regions. Results show that austenite(γ) and delta-ferrite(δ) phases make up most of the microstructure of additively fabricated SS316LSi steel. Within γ matrix, δ phase is dispersed both(within and along) grain boundaries, exhibiting a fine vermicular morphology. The bottom, middle,and top regions of WAAM deposited ASS exhibit similar values to those of wrought SS316L in the tensile and impact test findings. Notably, a drop in hardness values is observed as build height increases. During SEM examinations of fractured surfaces from tensile specimen, closed dimples were observed, indicating good ductility of as-built structure. Wear test findings show signs of mild oxidation and usual adhesive wear. By depositing a mechanically mixed composite layer, an increase in the oxidation percentage was discovered to facilitate healing of worn surfaces. The findings of this study will help in design, production and renovation of products/components that are prone to wear. WAAM-deposited ASS has rema.k.ble strength and ability to withstand impacts;it can be used in the production of armour plates for defence applications, mainly military vehicles and aircraft.

关键词： Metal additive deposition Defence applications Arc-based DED Characterization Wear behaviour Fractography

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Controlling Diffusion by Varying Width of Layers in Nano Channel

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Nano-Micro Letters 2012年第3期4卷 154-157页

作者： Ishu Goyal Sunita srivastava k.Ta.k.shwar Department of Physics Panjab University Computer Centre Panjab University

Diffusive dynamics of fluid forming layers of high and low density regions in a nanochannel has been *** coefficient in direction parallel and perpendicular to the confining wall has been found to show behaviour which is not observed in micro channel or bulk *** behaviour of diffusion is found to be controlled by the width of layers formed in nanochannel due to wall and particle *** is an important result as width of layers and hence flow of fluid inside nano pores/tube can be controlled by an external source.

关键词： Nanochannel Layer Diffusion

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Compositionally Graded Microstructure for Ag-Fe Nanoparticles

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Nano-Micro Letters 2012年第3期4卷 172-175页

作者： Chandan srivastava k.V.L.Sushma Department of Materials Engineering Indian Institute of Science

Ag-Fe nanoparticles with a highly Ag rich average composition were synthesized by the sonochemical ***-iron system exhibits a wide miscibility gap in the bulk ***,a graded compositional profile along the nanoparticle radius was *** at and near the surface of the nanoparticle contained both Ag and Fe *** composition got relatively deficient Fe towards the center of the particle with particle core made up of pure *** of Ag and Fe is confirmed by the absence of diffraction signal corresponding to pure Fe phase and presence of a paramagnetic phase in nanoparticles containing a diamagnetic(Ag)and ferromagnetic(Fe)elements.

关键词： Nanoparticles Electron Microscopy Ag-Fe Miscibility gap Solid solution Microstructure

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Review of near-shore satellite derived bathymetry: Classification and account of five decades of coastal bathymetry research

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Journal of Ocean Engineering and Science 2021年第4期6卷 340-359页

作者： Mohammad Ashphaq Pa.k.j k srivastava D Mitra National Hydrographic Office DehradunIndia University of Petroleum&Energy Studies(UPES) DehradunIndia Indian Institute of Remote Sensing DehradunIndia

The number of civilian,commercial and military applications are dependant on accurate knowledge of bathymetry of coastal ***,hydrographic surveying methods are used for bathymetric surveys carried by ship-based acoustic systems,but needs highcost *** technology has provided a cost-effective alternate means for charting near shore and inaccessible *** optical satellite data have capabilities to offer alternate solution in near-shore region,which has been researched for past 50 years,using evolving algorithms to estimate Satellite Derived Bathymetry(SDB).However,there is no agreement on use of terms like approach,model,method and techniques,which have been used varyingly and interchangeably as per context of SDB *** paper suggests a classification scheme for SDB algorithms which is also applicable to other Marine Remote Sensing *** this paper,based on literature available on SDB for the past five decades,an insight on SDB classification has been offered grounded in research *** SDB approaches,models,methods and techniques have been elaborated with chronological development,along with SDB studies based on them,their accuracy and errors in SDB *** have suggested a matrix of prerequisite satellite data,in-situ data resolution,methods and algorithms of SDB based on level of accuracy needs to be achieved,which will guide future researchers to select one as per their context of research.

关键词： Satellite derived bathymetry Hydrography Bio-optical model Physio-optical model

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Advances in the Structural Composition of Biomass:Fundamental and Bioenergy Applications

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Journal of Renewable Materials 2021年第4期9卷 615-636页

作者： Neha srivastava Akshay Shrivastav Rajeev Singh Mohammed Abohashrh k.R.srivastava Safia Irfan Manish srivastava P.k.Mishra Vijai kumar Gupta Vijay kumar Thakur Department of Chemical Engineering and Technology Indian Institute of Technology(BHU)Varanasi221005India Department of Chemical Engineering Madan Mohan Malaviya University of TechnologyGorakhpur273010India Department of Environmental Studies Satyawati CollegeUniversity of DelhiDelhi110052India Department of Basic Medical Sciences College of Applied Medical SciencesKing Khalid UniversityAbhaSaudi Arabia Departentof Biotechnology Faculty of BiosciencesIntegral UniversityLucknow226026India Biorefining and Advanced Materials Research Center Scotland’s Rural College(SRUC)EdinburghEH93JGUK

Increased environmental pollution due to the organic wastes over the world is one of the most burning *** organic wastes lie under the category of biodegradable waste and can be effectively degraded from their complex compound into simple one by the action of microbes or other living ***,lignocellulosic biomass is a major part of the biodegradable waste and belongs to the group of renewable energy source,which can be very effective for bioenergy *** are made up of different compounds such as cellulose,hemicelluloses,lignin and *** from these components,based on the structural analysis biomass also consist of bioactive substances such as carotenoids,flavonoids,lignin and *** review explores a complete overview of the classification,component and the structure of the ***,it discusses how biomasses can play the key role of substrate in many sectors such as industrial bioenergy production including gaseous and liquid biofuels.

关键词： Biomass classification composition bioactive substance biofuels

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Environmental Exposure to Lead as a Risk for Prostate Cancer

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Biomedical and Environmental Sciences 2002年第4期15卷 298-305页

作者： M．k．J．SIDDIQUI S．srivastava 等 IndustialToxicologyReserachCentre PostBoxNo.80.M.G.Marg.Lucknow226－001India Dr RMLAvadhUniversityFaizabad－224001India

Objective To evaluate the possible role of environmental exposure to lead as a risk factor for prostate pathology in patients suffering from prostate cancer (PCA) and benign prostate hyperplasia (BPH). Methods Blood lead (BPb) level was determined in PCA and BPH cases using a graphite furnace Atomic Absorption Spectrophotometer and compared with those in a control group living in the similar socioeconomic environment. Results BPb was significantly higher in PCA and BPH cases than in normals (Pk factor for prostate cancer and/or benign prostate hyperplasia possibly through generation of reactive oxygen species and/or reducing the level of zinc which acts as a cellular growth protector.

关键词： Benign prostate hyperplasia Prostate cancer Blood lead Atomic Absorption Spectrophotometer

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Optical properties of amorphous thin film of Se-Te-Ag system prepared by using thermal evaporation technique

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Progress in Natural Science:Materials International 2011年第1期21卷 36-39页

作者： Madhu MISHRA Rashmi CHAUHAN Anju kATIYAR k.k.srivastava Department of Physics Dayanand Braiendra Swarup D.B.S.(P.G.) CollegeKanpur(U.P.)India Department of Physics D.A-V.(P.G.) CollegeKanpur(U.P.)India Department of Physics Dayanand Brajendra Swarup D.B.S.(P.G.) CollegeKanpur(U.P.)India

Optical reflection and transmission spectra of Se80-xTe20Agx(where x=0,5,10 and 15,molar percent) chalcogenide thin films have been obtained in the range 300-1 200 nm at room *** samples are prepared by melt quenching technique and thin films are obtained by using vacuum evaporation technique on glass transition at room *** present paper reports the effect of Ag contents on various optical parameters such as optical band gap,refractive index,extinction coefficient,absorption *** spectra are used for calculating these optical *** band gap Egis determined from the plot of (ahv)1/2versus *** and imaginary parts of the dielectric constant changes slightly with the variation of Ag contents in different *** film exhibits indirect band gap which increases with increasing Ag *** observed behavior is explained on the basis of Davis and Mott model for the density of *** absorption coefficient of thin films exhibits linear dependence on photon *** optical parameters are calculated by using theory of *** the optical parameters change with the variation of the film *** spectrophotometer JASCO-UV/VIS/NIR is used to determine optical constants.

关键词： chalcogenide thin film band gap optical constant

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Delayed information induces oscillations in a dynamical model for infectious disease

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International Journal of Biomathematics 2019年第2期12卷 163-196页

作者： Anuj kumar Prashant k srivastava Anuradha Yadav School of Mathematics Thapar Institute of Engineering and Technology Patiala 147004 India Department of Mathematics Indian Institute of Technology Patna Patna 801103India

During disease outbreak,it has been observed that information about the disease prevalence induces the individuafs behavioral *** information is usually assumed to be generated by the density of infective individuals and active mass *** delay in reporting of these infective individuals may have its impact on generated ***,to study the impact of delay on information generation,and therefore on the disease dynamics,a delay differential equation model is proposed and *** dynamics of information with delay effect is also modeled by a separate rate *** analysis is performed and a unique infected equilibrium is obtained when the basic reproduction number(R0)is greater than one,whereas the disease free equilibrium always *** R0<1,the disease free equilibrium is found to be locally stable independent of delay *** unique infected equilibrium is found to be locally stable till delay reaches a threshold *** global stability of the unique infected equilibrium is also established under some parametric conditions by constructing a suitable Lyapunov *** occurrence of Hopf bifurcation is observed when the delay in information crosses the threshold ***,the direction and stability of bifurcating periodic solutions is ***,we observed the occurrence of Hopf-Hopf bifurcation at two different *** first delay threshold,the endemic equilibrium loses its st ability and produces periodic oscillations via Hopf *** further regains its stability at second delay threshold via another Hopf ***,the delay effect on information shows possibility of stability *** experiments are carried out to support the obtained analytical *** study infers that the disease will show persistent oscillations if there is a significant time lag in reporting of infective after the disease ***,the delay in dissemination of information shows rich and

关键词： Information behavioral response delay Hopf bifurcation Hopf-Hopf bifurcation

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