检索结果-南通市图书馆

settling behavior of non-spherical particles in power-law fluids:Experimental study and model development

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

Particuology 2019年第5期17卷 30-39页

作者： Zhengming Xu Xianzhi Song Gensheng Li Zhaoyu Pang Zhaopeng Zhu State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum Beijing 102249 China

Solid-particle settling occurs in many natural and industrial processes, such as in the transportation of drilling cuttings and fracturing proppant. Knowledge of the drag coefficient and settling velocity of cuttings and proppant is of significance to hydraulics design, wellbore cleanout, and fracture optimization. We conducted 553 tests to investigate the settling characteristics of spherical and non-spherical particles in power-law fluids. Three major particle shapes (spherical, cubic, and cylindrical) and eight different particle sphericities were used to simulate cuttings and proppant, and power-law fluids were applied to simulate drilling and fracturing fluids. Based on the data analysis, a new drag coefficient-particle Reynolds number correlation was developed to determine the drag coefficient in a power-law fluid for spherical and non-spherical particles. The drag coefficient increases as the sphericity decreases for the same particle Reynolds number. For a specific particle shape, the drag coefficient decreases as the particle Reynolds number increases, but the decreasing trend is reduced at high particle Reynolds number conditions. An explicit settling-velocity equation was proposed to calculate the settling velocity of spherical and non-spherical particles in power-law fluids by considering the effect of sphericity. A suitable range for the proposed model is 0.0001 settling velocity in power-law fluids with given particle and fluid properties.

关键词： settling velocity Drag coefficient Non-spherical particle Spherical particle Power-law fluids

settling,consolidation and shear strength behaviour of coal tailings slurry

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

International Journal of Mining Science and Technology 2020年第6期30卷 849-857页

作者： Shriful Islam David J.Williams Marcelo Llano-Serna Chenming Zhang School of Civil Engineering The University of QueenslandQueensland 4072Australia Department of Civil and Environmental Engineering Shahjalal University of Science and TechnologySylhet 3114Bangladesh Geotechnical Engineer Klohn Crippen Berger Ltd.Queensland 4101Australia

The volume change and shear strength behaviour of tailings slurry with the changes in gravimetric moisture content is important to effectively utilise the storage volume and analysis of dam failure *** testing of tailings from a slurry-like to soil-like state is a critical task,and conventional consolidation apparatus does not have the capability of doing such testing,as the tailings slurries contain high water *** tests conducted on slurries having a 25%solids concentration showed very low efficiency;final sediment was still *** intrinsic point was identified based on pore water pressure dissipation during consolidation tests in a slurry consolidometer that can define two states of the tailings ***-like and *** the slurry-like state,the volume change was greater for Slurry 2 than Slurry 1,while the inverse was observed in the soil-like *** evolution of peak vane shear strength with the changes in moisture content was almost similar for both samples and obeyed the power *** models have been developed and validated to predict the shear strength of materials at any gravimetric moisture content or void ratio.

关键词： settling Consolidation Vane shear strength Coal tailings slurry Slurry consolidometer

Coagulation enhanced electrokinetic settling of mature fine oil sands tailings

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2019年第2期29卷 199-208页

作者： Shriful Islam Julie Q.Shang Department of Civil and Environmental Engineering The University of Western Ontario Department of Civil and Environmental Engineering Shahjalal University of Science and Technology

The mature fine oil sand tailings(MFT) remain as slurry in the tailings pond for long time. The dewatering and consolidation of MFT for sustainable management is an important task for the mining industry. The objective of this study is to accelerate electrokinetic settling of MFT solids in suspensions in presence of optimal coagulant. In the first phase, optimal coagulant and coagulant dosage for settling of suspension are identified, i.e., ferric chloride at 350 mg/L. It is found that the chemical treatment is not much effective; the final solid content of the sediment is only 6.48% from an initial of 5%. In the second phase,combined coagulation and electrokinetic treatment is carried out to enhance the settling effect. The direct electric current is applied in continuous and intermittent modes on MFT suspensions placed in electrokinetic cell. The results show the final solid content reaches 23.74% under the combined application of350 mg/L ferric chloride and 218.75 V/m applied voltage gradient in the continuous mode. The intermittent current mode with 40% save in power consumption produces a settled sediment having 20.84% final solid content.

关键词： Electrokinetics Electrophoresis Coagulation settling Voltage gradient MFT

Swimming strategy of settling elongated micro-swimmers by reinforcement learning

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2020年第8期63卷 86-94页

作者： JingRan Qiu WeiXi Huang ChunXiao Xu LiHao Zhao Applied Mechanics Laboratory(AML) Department of Engineering MechanicsTsinghua University100084 BeijingChina

Particular types of plankton in aquatic ecosystems can coordinate their motion depending on the local flow environment to reach regions conducive to their growth or *** their swimming strategies with regard to the local environment is important to obtain in-depth understanding of their behavior in the aquatic *** the present research,to examine an impact of the shape and gravity on a swimming strategy,plankton is considered as settling swimming particles of ellipsoidal *** Q-learning approach is adopted to obtain swimming strategies for smart particles with a goal of efficiently moving upwards in a two-dimensional steady *** obtained from reinforcement learning are compared to those of naive gyrotactic particles that are modeled considering the behavior of realistic *** is found that the elongation of particles improves the performance of upward swimming by facilitating particles’resistance to the perturbation of *** the case when the settling velocity is included,the strategy obtained by reinforcement learning has similar performance to that of the naive gyrotactic one,and they both align swimmers in upward *** similarity between the strategy obtained from machine learning and the biological gyrotactic strategy indicates the relationship between the aspherical shape and settling effect of realistic plankton and their gyrotactic feature.

关键词： swimming particles ellipsoid settling reinforcement learning

High molecular weight guar gum assisted settling of fine solids in diluted bitumen:Effect of solvents

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2021年第6期18卷 1877-1886页

作者： Camila Santander Jing Liu Xiao-Li Tan Qi Liu Hong-Bo Zeng Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 1H9Canada

As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns,developing non-aqueous extraction(NAE)technique is of both fundamental and practical ***,the relatively high concentration of fine solids trapped in the extracted bitumen presents an obstacle for pipeline transport as well as upgrading and refining *** research attempts to provide a solution to fine solids removal without using synthetic additives or affecting bitumen recovery from NAE ***,naturally hydrophilic additives(i.e.,water and high molecular weight guar gum(HGG)produced from Cyamopsiste tragonolobuosr ***.)were introduced to promote the settling of fine solids suspended in bitumen-solvent solution,and the effects of solvents(i.e.,toluene,cyclohexane and their mixtures)were systematically *** size distribution analyzed by the focused beam reflectance measurements confirmed that the addition of water and HGG could promote the agglomeration and settling of fine solids in all solvents ***,the size range and quantity of the agglomerates vary significantly with the solvent's aromatic *** mixtures demonstrate a superior performance on removing fine solids from bitumen over single ***,in a 3:2 toluene/cyclohexane mixture,the solid content was lowered from 0.66 wt%to 0.09 wt%.

关键词： Non-aquoues extraction Fine solids Guar gum Agglomeration settling

A computational study of the role of particle size standard deviation on the collision frequency in differential settling

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2013年第1期28卷 34-45页

作者： C.HEILIGER N.B.KAYE F.Y.TESTIK Civil Engineering Clemson UniversityClemsonSC29634USA

The results of a simple computational model for differential settling are presented illustrating the significant role that particle size distribution plays in collision frequency and sedimentation rate of particles in a quiescent environment. The model tracks a large number of particles（order 10;） with log-normally distributed diameters,as they settle at their Stokes settling *** collisions are detected and result in larger particles that fall more rapidly.A number of simplifying assumptions are made in the model in order to avoid empirical correlations for phenomena such as collision efficiency and particle *** simplifying assumptions were needed to isolate and quantify the role of the particle size *** concentration profiles indicate that,even in the absence of collisions, the standard deviation（σ;） of the particle size strongly influences the bulk mass settling rate as,for largerσ;, more mass is concentrated in larger,faster falling *** collision frequency is also a strong function ofσ;. For a given mass concentration the collision frequency first increases linearly with increasingσ;as greater variation in particle size leads to greater variation in particle velocity,and shorter times for particles to catch each *** largerσ;more mass is concentrated in larger particles,so,for a given mass concentration,there are fewer particles per unit volume,increasing the mean distance between the particles and reducing the collision *** implications of these results for sedimentation measurement using optical attenuation techniques are discussed.

关键词： settling Sediment size distribution Sediment collision frequency Coefficient of variation

A new mechanism hammered out for settling the intellectual property rights dispute on motorcycle between Japan and China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

中国汽车（英文版） 2004年第4期 4-4页

Yundang Lake Gets Epic Facelift

在线全文

学校读者我要写书评

暂无评论

China Today 2024年第1期73卷 56-58页

作者： XIA YUANYUAN 不详

The transformation of Yundang Lake from a stinky lake to an urban reception hall has made it a showcase of ecologival restoration in *** settling down in the City of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the *** they saw Yundang Lake in west Xiamen,the couple knew they had hit the jackpot.“The picture of the beautiful lake circled by lush vegetation caught our *** knew this was the place we were looking for,”said ***,after setting foot in Xiamen,he told himself he had definitely made the right life decision.

关键词： Xiamen settling looking

Yundang Lake Gets Epic Facelift

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

China Report ASEAN 2024年第4期9卷 48-49页

作者： Xia Yuanyuan 不详

Before settling down in the city of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the *** they saw Yundang Lake in west Xiamen,the couple knew they had hit the jackpot.“The picture of the beautiful lake circled by lush vegetation caught our *** knew this was the place we were looking for,”said ***,after setting foot in Xiamen,he told himself he had definitely made the right life decision.

关键词： Xiamen settling looking