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Numerical Simulation of Bubble Formation at a Single Orifice in Gas-fluidized Beds with Smoothed Particle Hydrodynamics and Finite Volume Coupled Method

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Computer Modeling in Engineering & Sciences 2015年第1期104卷 41-68页

作者： F.Z.Chen H.F.Qiang W.r.Gao 601 Staff room Xi’an Hi–Tech InstituteXi’anShanxiPRCPC 710025

A coupled method describing gas–solid two-phase flow has been proposed to numerically study the bubble formation at a single orifice in gas-fluidized *** particles are traced with smoothed particle hydrodynamics,whereas gas phase is discretized by finite volume *** force,gas pressure gradient,and volume fraction are used to couple the two *** effect of injection velocities,particle sizes,and particle densities on bubble growth is analyzed using the coupled *** simulation results,obtained for two-dimensional geometries,include the shape and diameter size of a bubble as a function of time;such results are compared with experimental data,previous numerical results,and other approximate model predictions reported in the ***,the flow profiles of gas and particle phases and the temperature distribution by the heat transfer model around the forming bubble are also *** results show that the coupled method efficiently describes of the bubble formation in fluidized *** proposed method is applicable for solving gas–solid two-phase flow in fluidization.

关键词： coupled method smoothed particle hydrodynamics finite volumemethod bubble formation heat transfer fluidization

Intra-and inter-clonal tree growth variations of Hevea brasiliensis

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Journal of Forestry research 2012年第3期23卷 429-434页

作者： H.r.Naji M.H.Sahri Department of Forest Production Faculty of ForestryUniversiti Putra MalaysiaSelangor43400Malaysia Department of Forestry Faculty of AgricultureIlam UniversityIlam69315-516Iran

We evaluated the effects of planting densities （500, 1,000, 1,500 and 2,000 ***-1） on tree growth performance （diameter at base, diameter at breast height, and clear bole height） of two clones （rrIM 2020 and PrIM 2025） of nine years old plantations of rubber tree （Hevea brasiliensis Muell. Arg） in Malaysia. For the four planting densities of the two clones, basal area and diameter at breast height declined with increasing planting density. Clear bole heights were greatest at 1,500 *** lowest at 500 ***-1 for the clone rrIM 2020, and at 2,000 ***-1and 500 *** clone rrIM 2025. We conclude that the ideal planting density is 2,000 ***＂l for obtaining high volume of wood production and 500 trees-ha-1 for high wood quality.

关键词： clone planting density tree growth Hevea brasiliensis

Solitary Potential in a Space Plasma Containing Dynamical Heavy Ions and Bi-Kappa Distributed Electrons of Two Distinct Temperatures

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Communications in Theoretical Physics 2018年第1期69卷 107-114页

作者： M.Sarker B.Hosen M.r.Hossen A.A.Mamun Department of Physics Jahangirnagar University Department of General Educational Development Daffodil International University

The heavy ion-acoustic solitary waves(HIASWs) in a magnetized, collisionless, space plasma system(containing dynamical heavy ions and bi-kappa distributed electrons of two distinct temperatures) have been theoretically investigated. The Korteweg-de Vries(K-dV), modified K-dV(MK-dV), and higher-order MK-dV(HMK-dV) equations are derived by employing the reductive perturbation method. The basic features of HIASWs(viz. speed, polarity,amplitude, width, etc.) are found to be significantly modified by the effects of number density and temperature of different plasma species, and external magnetic field(obliqueness). The K-dV and HM-Kd V equations give rise to both compressive and rarefactive solitary structures, whereas the MK-dV equation supports only the compressive solitary structures. The implication of our results in some space and laboratory plasma situations are briefly discussed.

关键词：重离子独居温度血浆空间 Korteweg-de 电子分布式

The ruminal microbiome associated with methane emissions from ruminant livestock

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Journal of Animal Science and Biotechnology 2017年第2期8卷 289-299页

作者： Ilma Tapio Timothy J.Snelling Francesco Strozzi r.John Wallace Green Technology Natural Resources Institute FinlandJokioinenFinland rowett Institute of Nutrition and Health University of AberdeenForesterhillAberdeen AB16 5BDUK. PTP Via Einstein-Loc.Cascina Codazza26900 Lodiltaly

Methane emissions from ruminant livestock contribute significantly to the large environmental footprint of *** rumen is the principal source of methane, and certain features of the microbiome are associated with low/high methane phenotypes. Despite their primary role in methanogenesis, the abundance of archaea has only a weak correlation with methane emissions from individual animals. The composition of the archaeal community appears to have a stronger effect, with animals harbouring the Methanobrevibacter gottschalki clade tending to be associated with greater methane emissions. Ciliate protozoa produce abundant H_2, the main substrate for methanogenesis in the rumen,and their removal（defaunation） results in an average 11% lower methane emissions in vivo, but the results are not consistent. Different protozoal genera seem to result in greater methane emissions, though community types（A, AB, B and O） did not differ. Within the bacteria, three different ‘ruminotypes＇ have been identified, two of which predispose animals to have lower methane emissions. The two low-methane ruminotypes are generally characterized by less abundant H_2-producing bacteria. A lower abundance of Proteobacteria and differences in certain Bacteroidetes and anaerobic fungi seem to be associated with high methane emissions. rumen anaerobic fungi produce abundant H_2 and formate, and their abundance generally corresponds to the level of methane emissions. Thus, microbiome analysis is consistent with known pathways for H_2 production and methanogenesis, but not yet in a predictive manner. The production and utilisation of formate by the ruminal microbiota is poorly understood and may be a source of variability between animals.

关键词： Archaea Methane Microbiome rumen

Modeling and simulation of enhancement mode p-GaN Gate AlGaN/GaN HEMT for rF circuit switch applications

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Journal of Semiconductors 2017年第6期38卷 52-57页

作者： D.K.Panda T.r.Lenka Microelectronics and VLSI Design Group Department of Electronics and Communication Engineering National Institute of Technology Silchar Assam 788010 India

An enhancement mode p-GaN gate AlGaN/GaN HEMT is proposed and a physics based virtual source charge model with Landauer approach for electron transport has been developed using Verilog-A and simulated using Cadence Spectre,in order to predict device characteristics such as threshold voltage,drain current and gate *** drain current model incorporates important physical effects such as velocity saturation,short channel effects like DIBL（drain induced barrier lowering）,channel length modulation（CLM）,and mobility degradation due to *** predicted Id–V（ds）,Id–V（gs）,and C–V characteristics show an excellent agreement with the experimental data for both drain current and capacitance which validate the *** developed model was then utilized to design and simulate a single-pole single-throw（SPST）rF switch.

关键词： CLM DIBL GaN HEMT SPST Verilog-A

Shrinkage of magnetosphere observed by TC-1 satellite during the high-speed solar wind stream

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Science China(Technological Sciences) 2008年第10期51卷 1695-1703页

作者： H. rME I. DANDOUrAS C. M. CArr Centre d'Etude Spatiale des rayonnements BP 4346 31028 Toulouse cedex 4 France The Blackett Laboratory Imperial College London SW7 2BZ UK

During the interval 06:14―07:30 UT on August 24, 2005, since the Earth’s magneto- pause was suddenly compressed by the persistent high-speed solar wind stream with the southward component of the interplanetary magnetic field (IMF), the magnetopause moved inward for about 3.1 rE. Meanwhile, TC-1 satellite shifted from northern plasma sheet to the northern lobe/mantle region, although it kept inward flying during the interval 06:00―07:30UT. The shift of TC-1 from the plasma sheet to the lobe/mantle is caused by the simultaneous inward displacements of the plasma sheet and near-Earth lobe/mantle region, and their inward movement velocity is larger than the inward motion velocity of TC-1. The joint inward dis-placements of the magnetopause, the lobe/mantle region and the plasma sheet indicate that the whole magnetosphere shrinks inward due to the magnetospheric compression by the high-speed solar wind stream, and the magnetospheric ions are attached to the magnetic field lines (i.e. ‘frozen’ in magnetic field) and move inward in the shrinking process of magnetosphere. The large shrinkage of magne-tosphere indicates that the near-Earth magnetotail compression caused by the strong solar wind dynamic pressure is much larger than its thickening caused by the southward component of the IMF, and the locations of magnetospheric regions with different plasmas vary remarkably with the variation of the solar wind dynamic pressure.

关键词： solar wind dynamic pressure shrinkage of magnetosphere storm sudden commencement substorm

A Bayesian framework for adsorption energy prediction on bimetallic alloy catalysts

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npj Computational Materials 2020年第1期6卷 195-205页

作者： Osman Mamun Kirsten T.Winther Jacob r.Boes Thomas Bligaard SUNCAT Center for Interface Science and Catalysis Department of Chemical EngineeringStanford UniversityStanfordCA 94305USA SUNCAT Center for Interface Science and Catalysis SLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA 94025USA DTU Energy Department of Energy Conversion and StorageAnker Engelunds VejBuilding 3012800 Kgs.LyngbyDenmark

For high-throughput screening of materials for heterogeneous catalysis,scaling relations provides an efficient scheme to estimate the chemisorption energies of hydrogenated ***,conditioning on a single descriptor ignores the model uncertainty and leads to suboptimal prediction of the chemisorption *** this article,we extend the single descriptor linear scaling relation to a multi-descriptor linear regression models to leverage the correlation between adsorption energy of any two pair of *** a large dataset,we use Bayesian Information Criteria(BIC)as the model evidence to select the best linear regression ***,Gaussian Process regression(GPr)based on the meaningful convolution of physical properties of the metal-adsorbate complex can be used to predict the baseline residual of the selected *** integrated Bayesian model selection and Gaussian process regression,dubbed as residual learning,can achieve performance comparable to standard DFT error(0.1 eV)for most adsorbate *** sparse and small datasets,we propose an ad hoc Bayesian Model Averaging(BMA)approach to make a robust *** this Bayesian framework,we significantly reduce the model uncertainty and improve the prediction *** possibilities of the framework for high-throughput catalytic materials exploration in a realistic setting is illustrated using large and small sets of both dense and sparse simulated dataset generated from a public database of bimetallic alloys available in ***.

关键词： adsorption scaling bimetallic

High-temperature granulites and supercontinents

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Geoscience Frontiers 2016年第1期7卷 101-113页

作者： J.L.r.Touret M.Santosh J.M.Huizenga Institut de Mineralogie Physique des MateriauxCosmochimie(IMPMC)Sorbonne Universites et UPMC Univ Paris 06UMR CNRS 7590Museum National d'Histoire NaturelleIRD UMR 2064 Place JussieuF-FS005 ParisFrance School of the Earth Sciences and resources China University of Geosciences(Beijing)29 Xueyuan RoadBeijing 100083China Economic Geology research Institute(EGrU) College of ScienceTechnology and EngineeringJames Cook UniversityTownsvilleQueensland4811Australia Unit for Environmental Sciences and Management North-West UniversityPrivate Bag X60012520South Africa

The formation of continents involves a combination of magmatic and metamorphic processes. These processes become indistinguishable at the crust-mantle interface, where the pressure-temperature（P-T）conditions of（ultra） high-temperature granulites and magmatic rocks are similar. Continents grow laterally, by magmatic activity above oceanic subduction zones（high-pressure metamorphic setting）, and vertically by accumulation of mantle-derived magmas at the base of the crust（high-temperature metamorphic setting）. Both events are separated from each other in time; the vertical accretion postdating lateral growth by several tens of millions of years. Fluid inclusion data indicate that during the high-temperature metamorphic episode the granulite lower crust is invaded by large amounts of low H2O-activity fluids including high-density CO2 and concentrated saline solutions（brines）. These fluids are expelled from the lower crust to higher crustal levels at the end of the high-grade metamorphic event. The final amalgamation of supercontinents corresponds to episodes of ultra-high temperature metamorphism involving large-scale accumulation of these low-water activity fluids in the lower *** accumulation causes tectonic instability, which together with the heat input from the subcontinental lithospheric mantle, leads to the disruption of supercontinents. Thus, the fragmentation of a supercontinent is already programmed at the time of its amalgamation.

关键词： Continents Supercontinents Magmatism and metamorphism Fluids Tectonics

Toward the Optimization of the region-Based P300 Speller

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Computers, Materials & Continua 2021年第4期67卷 1169-1189页

作者： A.Benabid Najjar N.AlSahly r.AlShamass M.Hosny Department of Software Engineering King Saud UniversityRiyadh11451Saudi Arabia Department of Computer Science King Saud UniversityRiyadh11451Saudi Arabia

Technology has tremendously contributed to improving communication and facilitating daily ***-Computer Interface(BCI)study particularly emerged from the need to serve people with disabilities such as Amyotrophic Lateral Sclerosis(ALS).However,with the advancements in cost-effective electronics and computer interface equipment,the BCI study is flourishing,and the exploration of BCI applications for people without disabilities,to enhance normal functioning,is ***,the P300-based spellers are among the most promising applications of the BCI *** this context,the region-based paradigm for P300 BCI spellers was introduced in an effort to reduce the crowding effect and adjacency problem that might affect the detection of P300 *** study extends this line of research by investigating the effect,in terms of accuracy and usability,of the letters’distribution among the speller’s *** this purpose,a clustering algorithm is proposed,and two region-based layouts were generated by redistributing the letters based on their dissimilarity or their similarity.A pilot usability evaluation was also conducted in order to assess the usability of the different layouts in terms of effectiveness,efficiency,and *** results indicate that the distribution of the letters has an effect on the classification accuracy as well as the user ***,when considering short-term accuracy and cognitive effort,the original region-based layout outperforms other layouts.

关键词： Optimization clustering usability evaluation BCI region-based P300 speller