检索结果-南通市图书馆

Landau–Stanyukovich Rule and the Similarity parameter of Converging Shock Waves in Magnetogasdynamics

在线全文

学校读者我要写书评

暂无评论

Chinese physics Letters 2011年第9期28卷 170-173页

作者： Mithilesh singh L.p.singh Akmal Husain Department of Mathematics Dehradun Institute of TechnologyDehradunIndia Department of Applied Mathematics Institute of TechnologyBanaras Hindu UniversityIndia

Second-kind self-similar solutions to a problem of converging cylindrical shock waves in magnetogasdynamics are *** trial functions suggested by Chisnell and the shooting method of Landau–Stanyukovich are used to determine the similarity exponent for different values of specific heat ratioγand the parameter k,where kın(0,1].Detailed analyses of flow patterns for different values of adiabatic heat exponent and magnetic field strength are carried *** is observed that the general behavior of the velocity and density profiles is not affected in a magnetogasdynamics regime whereas there is an increase in the absolute value of the flow parameters with an increase in the magnetic field ***,the pressure profiles are greatly affected by the magnetic field interaction.

关键词： interaction Landau dynamics

Evolution of the paleogene succession of the western Himalayan foreland basin

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2013年第2期4卷 199-212页

作者： B.p.singh CAS in Geology.Banaras Hindu University

The paleogene succession of the Himalayan foreland basin is immensely important as it preserves evidence of India-Asia collision and related records of the Himalayan *** this paper,the depositional regime of the paleogene succession of the Himalayan foreland basin and variations in composition of the hinterland at different stages of the basin developments are *** paleogene succession of the western Himalayan foreland basin developed in two stages,*** stage and post-collisional *** the onset,chert breccia containing fragments derived from the hanging walls of faults and reworked bauxite developed as a result of erosion of the forebulge. The overlying early Eocene succession possibly deposited in a coastal system,where carbonates represent barriers and shales represent ***-section,the middle Eocene marl beds likely deposited on a tidal *** late Eocene/Oligocene basal Murree beds,containing tidal bundles,indicate that a mixed or semi-diurnal tidal system deposited the sediments and the sedimentation took place in a tidedominated *** the higher-up,the succession likely deposited in a river-dominated estuary or in meandering *** the beginning of the basin evolution,the sediments were derived from the precambrian basement or from the metasediments/volcanic rocks possessing terrains of the *** early and middle Eocene（54.7-41.3 Ma） succession of the embryonic foreland possibly developed from the sediments derived from the Trans-Himalayan schists and phyllites and Indus ophiolite of the north during syn-collisional *** detrital minerals especially the lithic fragments and the heavy minerals suggest the provenance for the late Eocene/Oligocene sequences to be from the recycled orogenic belt of the Higher Himalaya,Tethyan Himalaya and the Indus-suture zone from the north during post-collisional *** is also supported by the paleocurrent measurements those suggest main flows directed towards sou

关键词： Facies architecture provenance Basin evolution paleogene Himalayan foreland Tectonics

primary sclerosing cholangitis and the risk of colon neoplasia in patients with Crohn’s colitis

在线全文

学校读者我要写书评

暂无评论

Gastroenterology Report 2016年第3期4卷 226-231,I0002页

作者： Udayakumar Navaneethan tarun Rai preethi GK Venkatesh Ravi p Kiran Department of Gastroenterology Digestive disease InstituteThe Cleveland ClinicClevelandOHUSA Department of Colorectal Surgery Digestive disease InstituteThe Cleveland ClinicClevelandOHUSA

Background and aim:Crohn’s colitis(CC)is associated with primary sclerosing cholangitis(pSC).However the risk of colon cancer or dysplasia in CC and pSC is *** aim was to study the risk of colon neoplasia in CC in patients with and without ***:This is a nested,case-control cohort study of all patients diagnosed with concurrent CC and pSC,seen at the Cleveland Clinic between 1985 and ***-three patients with both CC and pSC were compared with a random sample of 159 CC controls without pSC during the same ***:Seven(16.3%)of 43 CC patients with pSC developed colon cancer or dysplasia,compared with 22(13.8%)of 159 controls(p=0.98).Of seven colon neoplasia cases in the pSC group,100%occurred proximal to the splenic flexure,compared with 50%(11/22)cases of colon neoplasia in controls occurring in the proximal colon(p=0.001).Based on Cox regression analysis,male gender independently increased the risk of neoplasia[hazard ratio(HR)=2.68;95%confidence interval(CI)1.30-5.54;p=0.008],as did age at CC diagnosis(HR=1.29;95%CI 1.14-1.47;pprine/6-mercaptopurine was protective(HR=0.30;95%CI 0.13-0.70;p=0.005).The presence of pSC did not increase the risk for colon neoplasia(HR=0.45;95%CI 0.18-1.13;p=0.09).Conclusions:CC patients with pSC appear not to be at increased risk of developing colon *** patients in our cohort with colon neoplasia and concurrent pSC,the neoplasia occurred in the proximal colon in all cases.

关键词： Crohn’s colitis primary sclerosing cholangitis colon neoplasia

Strength and deformation characteristics of steel fibrous concrete beams

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied physics & Engineering) 2007年第2期8卷 257-263页

作者： singh Bhupinder singh S.p. KAUSHIK S.K Department of Civil Engineering Indian Institute of Technology Roorkee 247 667 India Department of Civil Engineering National Institute of Technology Jalandhar 144 011 India

The results of an analytical investigation of the flexural behaviour of Steel Fibre Reinforced Concrete （SFRC） beams are presented. The complete response of the SFRC beams under displacement controlled static loading was obtained using nonlinear Finite Element （FE） techniques implemented with the help of ATENA 2D soRware. Issues relating to the behaviour of SFRC which have a direct bearing on the FE modelling are discussed with relevance to the software employed for the nonlinear analysis. Constitutive models amenable to numerical analysis for steel fibrous concrete are presented. The structural response throughout the loading regime was captured in terms of the load-deflection behaviour, which in addition to the post-peak response characterized the failure mode of the test beams. The crack patterns at crack initiation and at the end of the tests were also recorded. Experimental results from the specimens of two other investigators were used as control values for this investigation. The response of the specimens of this investigation was evaluated in terms of initial tangent stiffness, peak loads and toughness. Good match was obtained between the results from this investigation and corresponding experimentally obtained values, wherever available. The influence of the fibre content is reflected in the observed trends in peak loads, deflection at peak loads and toughness, which are in broad agreement with known behavioral patterns of SFRC.

关键词： Analysis Deformation Strength Steel Fibre Reinforced Concrete (SFRC) Toughness

Viscous cosmology in holographic dark energy with Granda–Oliveros cut-off

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2023年第2期75卷 144-156页

作者： Simran Kaur C p singh Department of Applied Mathematics Delhi Technological UniversityBawana RoadDelhi-110042India

We study the effect of bulk viscosity on holographic dark energy(HDE)with Granda–Oliveros infra-red *** focus on a generalized form of the bulk viscous coefficient which successfully describes the present-day evolution of the *** observe that the model with bulk viscosity provides an elegant description of the early and late-time evolution of the *** constrain the model through the combined observational data of the Strong Lensing System(SLS),measurements of Hubble parameter,Type Ia supernova data of pantheon sample and local H_(0)measured by *** best-fit values obtained from two different combinations of data,we estimate the present value of Hubble’s constant H_(0)=71.567-0.848+1.448and H_(0)=69.197-1.924+1.563,the deceleration parameter q_(0)=-0.535-0.016+0.016and q_(0)=-0.536-0.016+0.016,and the equation of state w_(0)=-0.690-0.010+0.010and w_(0)=-0.691-0.011+0.011,*** HDE model with bulk viscosity exhibits the phase transition from decelerated epoch to accelerated epoch.A comparison of the model with the standardΛCDM model is discussed with the statefinder and cosmographic parameters.

关键词： viscosity holographic dark energy cosmology

Motion through spherical droplet with non-homogenous porous layer in spherical container

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2020年第7期41卷 1069-1082页

作者： p.K.YADAV A.TIWARI p.singh Department of Mathematics Motilal Nehru National Institute of Technology AllahabadPrayagraj 211004India Department of Mathematics Birla Institute of Technology SciencePilani 333031Rajasthan Department of Mathematics National Institute of Technology PatnaPatna 800005India

The problem of the creeping flow through a spherical droplet with a non-homogenous porous layer in a spherical container has been studied ***’s model for the flow inside the porous annular region and the Stokes equation for the flow inside the spherical cavity and container are used to analyze the *** drag force is exerted on the porous spherical particles enclosing a cavity,and the hydrodynamic permeability of the spherical droplet with a non-homogeneous porous layer is *** is placed on the spatially varying permeability of a porous medium,which is not covered in all the previous works related to spherical *** variation of hydrodynamic permeability and the wall effect with respect to various flow parameters are presented and discussed *** streamlines are presented to discuss the kinematics of the *** previous results for hydrodynamic permeability and drag forces have been verified as special limiting cases.

关键词： non-homogenous porous medium Stokes equation Darcy’s law perme-ability parameter wall effect

Soil Carbon and Nitrogen in Response to perennial Bioenergy Grass, Cover Crop and Nitrogen Fertilization

在线全文

学校读者我要写书评

暂无评论

pedosphere 2017年第2期27卷 223-235页

作者： Upendra M. SAINJU Hari p. singh Bharat p. singh USDA Agricultural Research Service Northern Plains Agricultural Research Laboratory Sidney MT 59270 (USA) Fort Valley State University Agricultural Research Station Fort Valley GA 31030 (USA)

Cover crop and nitrogen （N） fertilization may maintain soil organic matter under bioenergy perennial grass where removal of aboveground biomass for feedstock to produce cellulosic ethanol can reduce soil quality. We evaluated the effects of cover crops and N fertilization rates on soil organic carbon （C）（SOC）, total N （STN）, ammonium N （NH4-N）, and nitrate N （NO3-N） contents at the 0-5, 5-15, and 15-30 cm depths under perennial bioenergy grass from 2010 to 2014 in the southeastern USA. Treatments included unbalanced combinations of perennial bioenergy grass, energy cane （Saccharum spontaneum L.） or elephant grass （pennisetum pur- pureum Schumazh.）, cover crop, crimson clover （Trifolium incarnatum L.）, and N fertilization rates （0, 100, and 200 kg N ha-l）. Cover crop biomass and C and N contents were greater in the treatment of energy cane with cover crop and 100 kg N ha-1 than in the treatment of energy cane and elephant grass. The SOC and STN contents at 0-5 and 5-15 cm were 9%-20% greater in the treatments of elephant grass with cover crop and with or without 100 kg N ha-1 than in most of the other treatments. The soil NO3-N content at 0--5 cm was 31%-45% greater in the treatment of energy cane with cover crop and 100 kg N ha-1 than in most of the other treatments. The SOC sequestration increased from 0.1 to 1.0 Mg C ha-1 year-1 and the STN sequestration from 0.03 to 0.11 Mg N ha-1 year-1 from 2010 to 2014 for various treatments and depths. In contrast, the soil NH4-N and NO3-N contents varied among treatments, depths, and years. Soil C and N storages can be enriched and residual NO3-N content can be reduced by using elephant grass with cover crop and with or without N fertilization at a moderate rate.

关键词： C and N storages C sequestration feedstock management practices N cycling nitrate soil organic matter

Rib stability: A way forward for safe coal extraction in India

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2017年第6期27卷 1087-1091页

作者： singh Satyendra K. Agrawal Harshit singh Awanindra p. Mining Methods and Design Simulation Research Group CSIR-Central Institute of Mining and Fuel Research (CSIR-CIMFR) Dhanbad 826015 India

Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&p) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safety(FOS), a ratio of the strength of rib to stress on it. Earlier formulations for rib stability when applied to case studies gave very low FOS value suggesting significant ground control problems, which were contrary to the field observations. This has necessitated the need to revisit the concept of rib stability. The stress coming on the rib is estimated with the use of numerical modeling technique using the FLAC^(3D) software. The methodology of assessing rib-stability with the help of suggested rib-strength formulation has been validated at eight Indian coal mines. The outcome of this study finds relevance and importance in ensuring underground coal liquidation with improved safety and conservation.

关键词： Rib stress estimation Rib-strength Rib-stability Numerical modeling Bord & pillar method Underground coal extraction

Constraining the variable generalized Chaplygin gas model in matter creation cosmology

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2024年第10期76卷 119-134页

作者： Yogesh Bhardwaj C p singh Department of Applied Mathematics Delhi Technological UniversityBawana RoadDelhi-110042India

We explore the variable generalized Chaplygin gas(VGCG)model in the theory of matter creation cosmology within the framework of a spatially homogeneous and isotropic flat Friedmann—Lemai tre—Robertson—Walker *** creation cosmology is based on reinterpretation of the energy–momentum tensor in Einstein's field *** creation corresponds to an irreversible energy flow from the gravitational field to the created matter *** variable Chaplygin gas(VCG)is also studied as a particular *** use the Markov chain Monte Carlo method to constrain the free parameters of three models,namely,Lambda-Cold-Dark matter(ΛCDM),VGCG and VCG models with and without matter creation from the latest observational data from baryon acoustic oscillations,cosmic chronometer,type Ia supernovae(pantheon)including gamma-ray bursts,quasars and the local measurement of H_(0) from R21 *** different combinations of dataset provide a fairly tight constraint on the parameters of theΛCDM,VGCG and VCG *** present values of various cosmological parameters are obtained,which are very close to theΛCDM ***,we perform stability analysis,Bayesian evidence analysis and information criteria analysis for these models through studying the sound speed,Bayes factor,and Akaike information criteria(AIC)and Bayesian information criteria(BIC)selection *** values of sound speed for VGCG and VCG models shows that both the models are *** to AIC,it is observed that VGCG and VCG models with matter creation are supported considerably less by current observations,while BIC shows that these models are not favoured by observational data.

关键词： cosmological model matter creation Chaplygin gas model dark energy