检索结果-南通市图书馆

SETTLING TESTS FOr TrACEr PArTICLES IN STATIC WATEr

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 1990年第4期5卷 477-490页

作者： Li, Zhangsu Cao, Gengxin Kiff, P.r. Waters, C.B. Nanjing Hydraulic research Inst Nanjing China

The production of fine sediments coated with radioisotopes to act as a tracer in studying the movement of dredging spoil involves some physical and chemical treatment of the sediment. The treatment can affect the electrochemical properties of the sediment and hence its behaviour in fresh and saline water. The effect of these changes on the degree of flocculation of the sediment has been studied by measuring the fall velocity distribution in a 4.4m settling column. The results of these tests show that the coating of inactive gold or silver on to natural sediment without any other pretreatment results in a tracer sediment having fall velocities similar to those of natural sediment. Other pretreatments result in variations in the fall velocity distributions owing to different degrees of flocculation induced by the chemical treatments. An artificial sediment consisting of finely ground scandium glass was also tested for comparison.

关键词： Soils Sediments

Modelling of Magnetorheological Fluids with Combined Lattice Boltzmann and Discrete Element Approach

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2010年第5期7卷 1095-1117页

作者： K.Han Y.T.Feng D.r.J.Owen Civil and Computational Engineering Centre School of EngineeringSwansea UniversitySA28PPUK

A combined lattice Boltzmann and discrete element approach is proposedfor numerical modelling of magnetorheological fluids. In its formulation, the particledynamics is simulated by the discrete element method, while the fluid field is resolvedwith the lattice Boltzmann method. The coupling between the fluid and the particlesare realized through the hydrodynamic interactions. Procedures for computing magnetic, contact and hydrodynamic forces are discussed in detail. The applicability ofthe proposed solution procedure is illustrated via a two-stage simulation of a Mr fluidproblem with four different particle volume fractions. At the first stage, simulationsare performed for the particle chain formation upon application of an external magnetic field;and at the second stage, the rheological properties of the Mr fluid underdifferent shear loading conditions are investigated with the particle chains establishedat the first stage as the initial configuration.

关键词： Magnetorheological fluids particle dynamics rheological properties magnetic interaction models lattice Boltzmann method discrete element method

An Explicit Integer Programming Model of the Minimal Spanning Tree Problem for Digraphs with Asymmetric Weights

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 Systems Engineering and Electronics 1998年第2期9卷 70-81页

作者： Feng Junwen(Naming University of Science and Technology, 210094, P. r. China) Nanjing University of Science and Technology 210094 P. R. China

As far as the minimal spanning tree problem for the digraph with asymmetric weightsis concerned, an explicit integer programming model is proposed, which could be solved successfullyusing the integer programming packages such as LINDO, and furthermore this model is extendedinto the stochastic version, that is, the minimal spanning tree problem for the digraph with theweights is not constant but random variables. Several algorithms are also developed to solve themodels. Finally, a numerical demonstration is given.

关键词： Minimal spanning tree Digraph Integer programming Asymmetric weight Stochastic spanning tree

Evaluation of alfalfa inter-seeding effect on bahiagrass baleage fermentation and lactating Holstein performance

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2014年第4期5卷 421-429页

作者： Michael E McCormick Kun Jun Han Vinicius r Moreira David C Blouin Southeast region LSU Agricultural Center 21549 Old Covington HwyHammondLA 70403USA Louisiana State University School of Plant Soil and Environmental SciencesBaton Rouge 70803USA Louisiana State University Agricultural Center Southeast Research StationP.O.Drawer 569Franklinton 70438USA Department of Experimental Statistics Louisiana State UniversityBaton Rouge 70803USA

Background：Previous research indicates that bahiagrass may be successfully conserved as baleage,but nutritive value is typically low for lactating dairy *** purpose of this study was to determine the effect of adding modest amounts of alfalfa forage（22%）,achieved by inter-seeding alfalfa into an existing bahiagrass pasture,on baleage nutritive value and lactation performance of Holstein *** treatments employed were monoculture bahiagrass baleage（MBB;negative control）,bahiagrass-alfalfa mixture baleage（BAB） and conventional corn silage（CCS;positive control）.Thirty six mid lactation Holstein cows[34.8 ±5.8 kg 3.5%fat-corrected milk and 112 ± 19 d in milk（DIM）]were stratified according to milk yield and DIM and assigned randomly to 1 of 3 forage *** were trained to Calan feeding gates and were offered a common CCS-based TMr in a 10-d covariance period followed by a 42-d treatment feeding ***：The BAB contained more protein and less NDF than MBB（12.6 vs 10.3%CP and 71.8 vs 76.6%NDF）.Diet DMI was similar for MBB and BAB（19.5 vs 21.6 kg/hd/d）,but cows consumed more of the CCS diet（25.5 kg/hd/d）than either baleage-based *** offered BAB tended to produce more milk than cows offered MBB based TMr（28.4 vs 26.1 kg/hd/d）,but both baleage diets generated less milk than CCS-based diets（33.1 kg/hd/d）.Milk cumpusition was similar across diets except for milk protein concentrations which were higher tor CCS than either MBB or BAB diets;however,milk urea nitrogen（MUN） was lowest for cows fed CCS *** BW gain was higher for BAB than MBB implying that a portion of the higher energy contributed by the alfalfa was being used to replenish weight on these mid lactation ***：Data from this study indicate that alfalfa inter-seeded in bahiagrass sod that produces BAB with as little as 22%alfalfa may improve nutritive value compared to monoculture bahiagrass baleage and marginally improve lactation performance of Holstein ***,t

关键词： Alfalfa Bahiagrass Baleage Corn silage Lactating dairy cows

Benchmark assessment of performance indices of a selection of hybrid nanofluids in a hybrid photovoltaic/thermal system

在线全文

学校读者我要写书评

暂无评论

Clean Energy 2022年第2期6卷 247-270页

作者： O.M.Amoo r.O.Fagbenle M.O.Oyewola Department of Mechanical Engineering University of IbadanIbadanOyo StateNigeria School of Mechanical Engineering Fiji National UniversityFiji

This research is a study assessing the performance of hybrid nanofluids in hybrid photovoltaic(PV)-thermal *** study addresses 10 hybrid nanofluids applied to hybrid PV-thermal *** transition to carbon-free energy can mitigate the worst effects of climate change,ensuring that global sustainability is *** energy is now responsible for one-third of the global capacity,of which 20%is attributed to solar *** continue to be economically viable,with declining costs driving *** study aims to compare the yearly performances of a model hybrid PV-thermal system using 10 different hybrid *** nanofluids constitute two or more dissimilar materials stably suspended in a base fluid(***).MATLAB and COMSOL Multiphysics®computational fluid dynamics software are employed together for the benchmarking assessment with good agreement *** fluid inlet temperatures(Tin∈[300,360]K),nanofluid volume concentrations(φ∈[0,4]%)and storage-tank volumes(V∈[50,300]L)were *** meteorological data applied were those for Lagos,Nigeria(6°27’55.5192”N,3°24’23.2128”E).The assessment based on analytical-numerical solutions reveals that the thermal enhancement by hybrid nanofluids ranges from 6.7%(graphene oxide[GO]-multiwalled carbon nanotube[MWCNT]/water)to 7%(ZnO-Mn-ZnFe2O4/water)forφ=2%and V=300 *** yearly exergy efficiency ranges from 2.8%(ZnO-Mn-ZnFe2O4/water)to 2.9%(GO-MWCNT/water),also forφ=2%and V=300 *** findings have implications for a vast range of industrial processes,expanding the knowledge that is critical to a sustainable future.

关键词： energy transformation hybrid photovoltaic-thermal(PV/T)system hybrid nanofluids COMSOL Multiphysics® MATLAB enhancements

Phage-mediated horizontal gene transfer and its implications for the human gut microbiome

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Gastroenterology report 2022年第1期10卷 78-89页

作者： Tatiana Borodovich Andrey N.Shkoporov r.Paul ross Colin Hill APC Microbiome Ireland University College CorkCorkIreland School of Microbiology University College CorkCorkIreland

Horizontal gene transfer(HGT)in the microbiome has profound consequences for human health and *** spread of antibiotic resistance genes,virulence,and pathogenicity determinants predominantly occurs by way of *** exists of extensive horizontal transfer in the human gut *** transduction is a type of HGT event in which a bacteriophage transfers non-viral DNA from one bacterial host cell to *** abundance of tailed bacteriophages in the human gut suggests that transduction could act as a significant mode of HGT in the gut *** we review in detail the known mechanisms of phage-mediated HGT,namely specialized and generalized transduction,lateral transduction,gene-transfer agents,and molecular piracy,as well as methods used to detect phage-mediated HGT,and discuss its potential implications for the human gut microbiome.

关键词： gut phageome horizontal gene transfer gene transduction phage-mediated gene transfer

Simulation of Plasma Flow Injectionwith Multi-Hierarchy Model Aiming Magnetic reconnection Studies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2012年第3期11卷 1006-1021页

作者： S.Usami H.Ohtani r.Horiuchi M.Den Department of Helical Plasma research National Institute for Fusion ScienceToki509-5292Japan The Graduate University for Advanced Studies(Soken-dai) Toki509-5292Japan National Institute of Information and Communications Technology Koganei 184-8795Japan

A multi-hierarchy simulation model aiming magnetic reconnection studies is developed and improved in which macroscopic and microscopic physics are computed consistently and *** physics is solved by magnetohydrodynamics(MHD)algorithm,while microscopic dynamics is expressed by particle-in-cell(PIC)*** multi-hierarchy model relies on the domain decomposition method,and macro-and micro-hierarchies are interlocked smoothly by hand-shake *** examination,plasma flow injection is simulated in the multihierarchy *** is observed that plasmas flow from a macro-hierarchy to a microhierarchy across the magnetic field smoothly and continuously.

关键词： Multi-hierarchy simulation magnetic reconnection MHD PIC

IMEX Evolution of Scalar Fields on Curved Backgrounds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2009年第10期6卷 1063-1094页

作者： S.r.Lau H.P.Pfeiffer J.S.Hesthaven Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Theoretical Astrophysics and relativity Group 130-33 California Institute of TechnologyPasadenaCA 91125USA Also at the Department of Mathematics and Statistics University of New MexicoAlbuquerqueNM 87131USA.

Inspiral of binary black holes occurs over a time-scale of many orbits,far longer than the dynamical time-scale of the individual black *** evolutions of a binary system therefore require excessively many time-steps to capture interesting *** present a strategy to overcome the Courant-Friedrichs-Lewy condition in such evolutions,one relying on modern implicit-explicit ODE solvers and multidomain spectral methods for elliptic *** analysis considers the model problem of a forced scalar field propagating on a generic curved ***,we encounter and address a number of issues pertinent to the binary black hole problem in full general *** to the Schwarzschild geometry in KerrSchild coordinates,we document the results of several numerical experiments testing our strategy.

关键词： Implicit-explicit schemes spectral methods numerical relativity black holes

Manual of neonatal surgical intensive care /

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论