检索结果-南通市图书馆

Effect of particle stress tensor in simulations of dense gas-particle flows in fluidized beds

在线全文

学校读者我要写书评

暂无评论

Particuology 2018年第3期16卷 31-43页

作者： Mohammad Reza Haghgoo donald j. Bergstrom Raymond j. Spiteri Department of Mechanical Engineering University of Saskatchewan Saskatoon SK SFN 5A9 Canada Department of Computer Science University of Saskatchewan Saskatoon. SK S7N 5C9 Canada

A two-fluid model based on the kinetic theory of granular flow for the rapid-flow regime and the Coulomb friction law for the quasi-static regime is applied to predict the hydrodynamics of dense gas-particle flow in a three-dimensional fluidized bed. Two different models for the particle stress tensor that use different constitutive equations in the elastic-inertial regime are examined to assess their ability to predict bed dynamics. To understand how particle stress models affect structural features of the flow, a quantitative analysis is performed on some important aspects of the mechanics of bubbling beds that have received relatively little attention in the literature. Accordingly, different flow regimes are identified in the context of fluidized beds through the dimensionless inertial number, and the main characteristics of each regime are discussed. In addition, how the particle stress tensor manifests itself in the bubble characteristics, natural frequency of the bed, and particle Reynolds stress are investigated, all of which help to better understand the complex dynamics of the fluidized bed. The numerical results are validated against pub- lished experimental data and demonstrate the significant role of the stress tensor in the elastic-inertial regime.

关键词： Two-fluid model Inertial number Fluidized bed Flow regime Particle Reynolds stress MFIX

Bioacoustic variation of swimbladder disturbance sounds in Neotropical doradoid catfishes （Siluriformes： Doradidae, Auchenipteridae）： Potential morphological correlates

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

Current Zoology 2012年第1期58卷 171-188页

作者： Kaatz, Ingrid M. Stewart, donald j. Department of Environmental and Forest Biology SUNY College of Environmental Science and Forestry Syracuse NY 13210 USA

Swimbladder disturbance sounds of doradoid catfishes （Doradidae and Aucheniptefidae） demonstrated striking waveform and spectrographic variation. We surveyed sounds of 25 doradoid species in 20 genera comparing these to sounds of four vocal outgroup catfish families. Sounds were either continuous waveforms （lacking interpulses） or pulsed （groups of pulses repeated at fixed temporal intervals）. This is the first evidence for swimbladder calls with fixed interpulse patterns in catfishes. Vocal mechanism components that were similar between doradids and auchenipterids included： swimbladder shape, swimbladder dimensions and sonic muscle-somatic index. Morphological traits that showed variation among taxa and were evaluated for po- tential correlates of call diversity are： 1） diverticula （marginal outpocketings of the swimbladder with no connection to inner ear） and 2） elastic spring apparatus Mtillerian rami （ESA-Mr）. Within the doradid subfamilies and within the Auchenipteridae most species differed significantly in dominant frequency with frequency ranges overlapping to some extent for most. Doradid swim- bladder diverticula did not explain dominant frequency variation within the doradoid superfamily. Some doradids with conical ESA-Mr had the highest dominant frequency sounds. Auchenipterids included both relatively lower and higher dominant fre- quency sound producers but lacked diverticula and had discoidal ESA-Mr. Comparing a phylogeny of doradoid genera with out- group taxa, we infer that complex diverticula and conical ESA-Mr are derived characters within the Doradidae. Species repre- senting outgroup families produced either continuous lower dominant frequency sounds （aspredinids, mochokids and pseudopimelodids） or pulsed higher dominant frequency sounds （pimelodids） [Current Zoology 58 （1）： 171-188, 2012].

关键词： Catfishes Communication Signal evolution Vocal mechanisms

Characterization of Kiwifruit Xyloglucan

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

j.urnal of Integrative Plant Biology 2009年第10期51卷 933-941页

作者： Xingj.n Li Naoki Sakurai donald j. Nevins Academy of the State Administration of Grains Beijing 100037 China Graduate School of Biosphere Science Hiroshima University Kagamiyama 1-7-1 Higashi-hiroshima 739-8521 Japan Department of Plant Sciences University of California Davis CA 95616 USA

Structural characteristics of xyloglucan are constant in the pericarp cell walls of kiwifruit （Actinidia deliciosa） throughout fruit enlargement and maturation. Most of the xyioglucan （XG） persists in the cell walls of ripe kiwifruit. XG from the pericarp tissues of 36-h ethylene-treated kiwifruit was extracted as hemicellulose Ⅱ （HC-Ⅱ） with 4.28 M KOH containing 0.02% NaBH4, and purified using iodine precipitation and subsequent anion-exchange chromatography. This purifying protocol increased XG purity from 50 mol% in HC-Ⅱ fraction to 62 mol% in the purified XG powder. The molar ratio of glucose： xylose： galactose： fucose in the purified XG was 10： 6.9： 2.1： 0.3. Gel permeation chromatography indicated that purified XG had an average molecular-mass of 161 KDa, a value that exceeds the 95 KDa Mr determined for total polymeric sugars. Sugar linkage analysis confirmed the lack of fucose in the kiwifruit XG, but a small amount of arabinoxylan and low Mr glucomannan remained associated with this fraction.

关键词： Actinidia deliciosa cell walls glucomannan hemicellulose sugar linkage analysis xyloglucan

A SURVEY OF THE HOLARCTIC LINYPHIIDAE (ARANEAE),A REVIEW OF THE ERIGONINE GENUS ZORNELLA j.CKSON, 1932

在线全文

学校读者我要写书评

暂无评论

动物分类学报 2007年第1期32卷 21-34页

作者： Yuri M. Marusik donald j. Buckle Seppo Koponen Institute for Biological Problems of the North Portovaya Str. 18 Magadan 685000 Russia 620 Albert Avenue Saskatoon Saskatchewan S7N 1G7 Canada Zoological Museum University of Turku FI-20014 Turku Finland

The Holarctic erigonid genus Zornella has been surveyed. Four species are recognized in this genus, two Palaearctic: ***(***,11879) & *** ***., and two Nearctic: ***(Banks, 1906) & *** Chamberlin,*** is demonstrated that neither nearctic species is conspecific with *** as was thought by Holm and other authors. *** ***. is described from northeastern Siberia. All of the species are illustrated and their distributions mapped.

关键词： Spiders Araneae Erigoninae Holarctic Zornella new species redescription

Time Scale of Partial Melting of KLB-1 Peridotite: Constrained from Experimental Observation and Thermodynamic Models

在线全文

学校读者我要写书评

暂无评论

j.urnal of Earth Science 2018年第2期29卷 245-254页

作者： Wei Du Li Li donald j.Weidner State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Mineral Physics Institute Department of Geosciences University of New York at Stony Brook

Partial melting experiments were carried on KLB-1 peridotite, a xenolith sample from the Earth＇s upper mantle, at 1.5 GPa and temperatures from 1 300 to 1 600 ℃, with heating time varies from 1 to 30 min. We quantify the axial temperature gradient in the deformation-DIA appa- ratus （D-DIA） and constrain the time scale of partial melting by comparing experimental observa- tions with calculated result from pMELTS program. The compositions of the liquid phase and the coexisting solid phases （clinopyroxene, orthopyroxene, and olivine） agree well with those calculated from pMELTS program, suggesting that local chemical equilibrium achieves during partial melting, although longer heating time is required to homogenize the bulk sample. The Mg# （=Mg/（Mg＋Fe） moi.%） of olivines from the 1-minute heating experiment changed continuously along the axial of the graphite capsule. A thermal gradient of 50 ℃/mm was calculated by comparing the Mg# of oli- vine grains with the output of pMELTS program. Olivine grains at the hot end of the graphite cap- sule from the three experiments heated at 1 400 ℃ but with different annealing time show consis- tence on Mg#, indicating that partitioning of Fe2＋ between the olivine grains and the silicate melt happened fast, and partial melting occurs in seconds.

关键词： peridotite partial melting temperature gradient pMELTS program.

State of the art of friction modelling at interfaces subj.cted to elastohydrodynamic lubrication(EHL)

在线全文

学校读者我要写书评

暂无评论

Friction 2021年第2期9卷 207-227页

作者： Zhuming BI donald W.MUELLER Chris W.j.ZHANG Civil and Mechanical Engineering Purdue University Fort WayneIN 46805USA Department of Mechanical Engineering University of SaskatchewanSaskatoon SK S7N 5A9Canada

Elastohydrodynamic lubrication(EHL)is a type of fluid-film lubrication where hydrodynamic behaviors at contact surfaces are affected by both elastic deformation of surfaces and lubricant *** of contact interfaces under EHL is challenging due to high nonlinearity,complexity,and the multi-disciplinary *** paper aims to understand the state of the art of computational modelling of EHL by(1)examining the literature on modeling of contact surfaces under boundary and mixed lubricated conditions,(2)emphasizing the methods on the friction prediction occurring to contact surfaces,and(3)exploring the feasibility of using commercially available software tools(especially,Simulia/Abaqus)to predict the friction and wear at contact surfaces of obj.cts with relative reciprocating motions.

关键词： elastohydrodynamic lubrication(EHL) lubricant rheology finite element analysis(FEA) friction prediction Simulia/Abaqus surface roughness coefficient of friction(CoF)

Dendritic Cells as a Pharmacological Target of Traditional Chinese Medicine

在线全文

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2006年第6期3卷 401-410页

作者： Xin Chen Lu Yang O. M. zack Howard j.ost j. Oppenheim Basic Research Program SAIC-Frededck Inc. NCI-Frederick ImQuest BioSciences Inc. 7340 Executive Way Frederick MD 21704 Laboratory of Molecular Immunoregulation Center for Cancer Research NCI-Frederick Frederick Maryland 21702-120

Dendritic cells （DCs） represent a heterogeneous population of professional antigen-presenting cells （APCs） that play a central role in the initiation and regulation of immune responses. There is considerable evidence that DCs can be used as therapeutic targets for pharmacological modulation of immune responses. Traditional Chinese medicine （TCM） has a long-standing history of using herbal medicine in the treatment of variety of human diseases. Many of the clinical effects of TCM have reportedly been attributed to the up- or down-regulation of immune responses. Accumulating evidence indicates that TCM and its components can interfere with immune responses at the earliest stage by targeting key functions of DCs. Here, we review those published studies of TCM with respect to their effects on immunobiological functions of DCs. Investigations based on both chemical entities derived from TCM as well as TCM herbal mixtures are presented. These studies suggest that various TCM herbal medicines have the capacity to inhibit or promote maj.r functions of DCs, such as differentiation, maturation, cytokine production, survival, antigen uptake and presentation as well as trafficking. These studies have revealed novel biological effects of TCM and documented the utility of this approach to discover novel biological modifier of DC functions derived from natural sources.

关键词： dendritic cell traditional Chinese medicine

A Model of the Universe that Can Explain Dark Matter, Dark Energy, and the Fourth Space Dimension

在线全文

学校读者我要写书评

暂无评论

j.urnal of Modern Physics 2016年第10期7卷 1247-1276页

作者： donald j. Koterwas Retired Monument CO USA Department of Earth Space and Graphic Sciences United States Military Academy West Point NY USA Department of Civil Engineering and Engineering Mechanics and Department of Optics University of Arizona Tucson AZ USA

This paper explains how a model of the universe can be constructed by incorporating time and space into geometry in a unique way to produce a 4-space dimension/1-time dimension model. The model can then show how dark matter can be the gravity that is produced by real matter that exists throughout our entire universe. The model can also show how dark energy is not an increase in energy that is causing the accelerated expansion of the universe, but is an accelerating decrease in matter throughout the universe as the stars and galaxies in the universe continue to convert matter into energy during their life cycles. And then the model can show how a fourth space dimension must exist in our universe to locate a point in space.

关键词： Universe Dark Matter Dark Energy Gravity Fourth Space Dimension

Adult neural stem cell plasticity

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

Neural Regeneration Research 2019年第2期14卷 256-257页

作者： Elizabeth j.Sandquist donald S.Sakaguchi Department of Zoology Weber State University Department of Genetics Development and Cell Biology Iowa State University Neuroscience Program Iowa State University Nanovaccine Institute Iowa State University

Stem cells derived from adult tissues have long been consideredmultipotent, able to differentiate into a limited number of cell typesfound in their tissue of origin. Embryonic stem cells, in contrast,are pluripotent, which may differentiate into almost all cell *** the ability to create induced pluripotent stem cells from somaticcells now available, the properties of multipotent stem cellsare being re-evaluated. If adult cells may be reverted to pluripotentstem cells, can multipotent stem cells also be manipulated towardspluripotency? Advancements in biotechnology now allow for bettermethods to investigate stem cell plasticity, such as the relativeinfluence of external versus intrinsic factors on cell fate. Recentstudies indicate that adult neural stem cells (NSCs) demonstrategreater plasticity under certain conditions, resulting in the derivationof a variety of cell types including muscle, hematopoietic, andepithelial cells. This suggests that NSCs may provide a potentialsource of rare cell types for clinical application as an alternative toembryonic stem cells. Producing rare cell types from NSCs ratherthan embryonic stem cells avoids the ethical issues surrounding theuse of this cell type. Further, NSCs may be an advantageous sourcecompared to induced pluripotent stem cells, which are difficult tocreate, expensive, and time-consuming to

关键词： cells stem cell NSCs types