检索结果-南通市图书馆

Numerical modelling of post-failure behaviors of coal specimens

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 514-531页

作者： Ajeet Yadav Bhaskara Behera Gauri Shankar Prasad Singh Sanjay Kumar Sharma Department of Mining Engineering Indian Institute of Technology(Banaras Hindu University)VaranasiUttar Pradesh221005India

A modelling approach consisting of best-fit relations to estimate the post-yield strength parameters is presented for simulating post-peak behavior beyond the point of residual strength of coal pillars having different w/h *** model was developed based on back-analysis of the complete stress-strain behavior of specimens belonging to six different Indian coal seams with different w/h ratios of 0.5 *** was found that the simultaneous degradation of the cohesion and friction angle of the Mohr-Coulomb rock material characterizes the post-peak strength behavior of the *** resulting expressions are simplistic as they require parameters that can be easily determined using uniaxial and triaxial compression ***,the developed model was validated by simulating the triaxial tests of coal specimens with different sizes under varying confining stresses and comparing its findings with the published test *** study showed that its implementation in the numerical model could reproduce laboratory-observed mechanical response,deformation behavior,and failure mechanism very closely.

关键词： Strain softening Dilatancy Interface shape effect Residual strength

Behaviour of layered sandstone under Brazilian test conditions:Layer orientation and shape effects

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 Rock Mechanics and Geotechnical Engineering 2013年第5期5卷 366-377页

作者： Abbass Tavallali André Vervoort Department of Civil Engineering University of Leuven

The experimental study in this paper focuses on the effects of the layer orientation and sample shape on failure strength and fracture pattern of samples tested under Brazilian test conditions(*** loading of cylindrical discs)for one particular layered sandstone which is from Modave in the south of *** variations of the strength in combination with the failure patterns are examined as a function of the inclination angle between the layer plane and the loading *** experimental,results clearly show that the induced fracture patterns are a combination of tensile and/or shear *** shape effect experiments the layer thickness and the number of layer boundaries are *** blocks of Modave sandstone are used to prepare *** layer thickness is different among the various blocks,but the layer thickness in each studied rock block can be considered to be constant;hence,the number of layer boundaries changes according to the sample diameter for samples of the same *** experimental study shows that the layer thickness plays a more important role than the number of layer boundaries per sample.

关键词： Layered sandstone Brazilian test Fracture pattern Layer activation shape effect

Magnetohydrodynamics hemodynamics hybrid nanofluid flow through inclined stenotic artery

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 459-476页

作者： B.K.SHARMA R.GANDHI T.ABBAS M.M.BHATTI Department of Mathematics Birla Institute of Technology and SciencePilani 333031India Department of Mathematics Division of Science and TechnologyUniversity of EducationLahore 54770Pakistan College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina

The present study aims to perform computational simulations of twodimensional(2D)hemodynamics of unsteady blood flow via an inclined overlapping stenosed artery employing the Casson fluid model to discuss the hemorheological properties in the arterial region.A uniform magnetic field is applied to the blood flow in the radial direction as the magneto-hemodynamics effect is *** entropy generation is discussed using the second law of *** influence of different shape parameters is explored,which are assumed to have varied shapes(spherical,brick,cylindrical,platelet,and blade).The Crank-Nicolson scheme solves the equations and boundary conditions governing the *** a given critical height of the stenosis,the key hemodynamic variables such as velocity,wall shear stress(WSS),temperature,flow rate,and heat transfer coefficient are computed.

关键词： overlapping stenosis hematocrit-dependent viscosity Au-Cu/blood hybrid nanofluid entropy generation shape effect

Growing actin networks regulated by obstacle size and shape

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2017年第2期33卷 222-233页

作者： Bo Gong Ji Lin Jin Qian Department of Engineering Mechanics Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou 310027 China

Growing actin networks provide the driving force for the motility of cells and intracellular pathogens. Based on the molecular-level processes of actin polymerization, branching, capping, and depolymerization, we have developed a modeling framework to simulate the stochastic and cooperative behaviors of growing actin networks in propelling obstacles, with an emphasis on the size and shape effects on work capacity and filament orientation in the growing process. Our results show that the characteristic size of obstacles changes the protrusion power per unit length, without influencing the orientation distribution of actin filaments in growing networks. In contrast, the geometry of obstacles has a profound effect on filament patterning, which influences the orientation of filaments differently when the drag coefficient of environment is small, intermediate, or large. We also discuss the role of various parameters, such as the aspect ratio of obstacles, branching rate, and capping rate, in affecting the protrusion power of network growth.

关键词： Actin network Growth dynamics Monte Carlo simulation Size effect shape effect

Rod-like mesoporous silica nanoparticles facilitate oral drug delivery via enhanced permeation and retention effect in mucus

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第10期15卷 9243-9252页

作者： Wenjuan Liu Luyu Zhang Zirong Dong Kaiheng Liu Haisheng He Yi Lu Wei Wu Jianping Qi School of Pharmacy Key Laboratory of Smart Drug Delivery of MOEFudan UniversityShanghai 201203China

The physiochemical characteristics of nanoparticles affect their in vitro and in vivo performance significantly,such as diameter,surface chemistry,and *** paper disclosed the effect of enhanced permeation and retention(EPR)in mucus caused by nanoparticle shape on improving oral *** spherical and rod-like mesoporous silica nanoparticles(MSNs)were used to evaluate shape effect of EPR in *** was loaded in MSNs as model *** in vitro release of fenofibrate from MSNs was dependent on nanoparticle shapes,but faster than that of raw *** drug release slowed down with the increase of aspect ratio due to longer channels in rod-like MSNs with higher aspect ***,in vivo study showed that the oral bioavailability of fenofibrate was the highest after loading in rod-like MSNs with aspect ratio of *** in vitro study of mechanisms revealed that superior mucus diffusion ability of rod-like MSNs with aspect ratio of 5 was conductive to higher ***,more rod-like MSNs with higher aspect ratio were able to diffuse into mucus and reside there compared to spherical and short counterparts,which demonstrated higher aspect ratio was beneficial to EPR effect of nanoparticles in *** study provides significant implication in rational oral drug carrier design.

关键词： mesoporous silica nanoparticles shape effect fenofibrate mucus layer enhanced permeation and retention effect

CALCULATION OF THE VACANCY VOLUME OF METALS BY MODIFIED BROOKS' MODEL

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

Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 888-893页

作者： W.H.Qi M.P.Wang W.Y.Hu B.W.Zhang SchoolofMaterialsScienceandEngineering JiangsuUniversityZhenjiang212013China／／SchoolofMaterialsScienceandEngineeringCentralSouthUniversityChangsha410083China SchoolofMaterialsScienceandEngineering CentralSouthUniversityChangsha410083China DepartmentofAppliedPhysics HunanUniversityChangsha410082China

To modify the shape difference between the spherical vacancy and the realistic vacancy, a shape factor is introduced into Brooks' vacancy model. It is shown that the modified model is more efficient in predicting the vacancy volume of metals than the original one, and the calculated vacancy volumes of 17 metals by the modified model agree with the values reported in literatures. Furthermore, the present results show that the vacancy shape may contribute 2%-9% to the whole vacancy volume.

关键词： vacancy volume shape effect metals

Evaluation of rockburst proneness considering specimen shape by storable elastic strain energy

在线全文

学校读者我要写书评

暂无评论

Deep Underground Science and Engineering 2022年第2期1卷 116-130页

作者： Song Luo Fengqiang Gong School of Resources and Safety Engineering Central South UniversityChangshaChina School of Civil Engineering Southeast UniversityNanjingChina

To systematically assess the rockburst proneness considering specimen shape,multiple groups of laboratory tests were performed on 5 rock materials in cylindrical and cuboid *** linear energy storage(LES)law of both cylindrical and cuboid rock specimens under uniaxial compressive load was confirmed,and the energy storage coefficient was found to be unrelated to specimen *** the basis of LES law,two rockburst proneness indexes,namely the strain energy storage index(W_(et))and the potential energy of elastic strain(PES),were ***,the W_(et),PES,peak-strength strain energy storage index(W_(et))p,and peak-strength potential energy of elastic strain(PESp)were used to assess the rockburst proneness of the cylindrical and cuboid *** addition,the fragment ejection course of specimens under test was recorded by a high-speed ***,the rockburst proneness judgments obtained from the 4 indexes were compared with the qualitative data during rock *** results show that,under similar stress conditions,specimen shape has an ignorable effect on the rockburst proneness as a *** judgment accuracy of the two modified indexes,especially that of the PESp,is favorably improved to evaluate the rockburst proneness of both cylindrical and cuboid ***,misjudgment ofW_(et)^(p)and PESp may still occur in the assessment of rockburst proneness as these two indexes only consider the energy state before rock peak strength and the W_(et)^(p)is formulated in a ratio form.

关键词： cuboid specimen elastic strain energy energy storage rockburst proneness shape effect uniaxial compression

Behaviour of layered sandstone under Brazilian test conditions:Layer orientation and shape effects

在线全文

学校读者我要写书评

暂无评论

Behaviour of layered sandstone under Brazilian test conditio...

Experimental study on dimension-form effect for compressive strength of coal

第13届全国岩石动力学学术会议

作者： Abbass Tavallali André Vervoort Department of Civil Engineering University of LeuvenKasteelpark Arenberg 403001 LeuvenBelgium

The experimental study in this paper focuses on the effects of the layer orientation and sample shape on failure strength and fracture pattern of samples tested under Brazilian test conditions(*** loading of cylindrical discs) for one particular layered sandstone which is from Modave in the south of *** variations of the strength in combination with the failure patterns are examined as a function of the inclination angle between the layer plane and the loading *** experimental,results clearly show that the induced fracture patterns are a combination of tensile and/or shear *** shape effect experiments the layer thickness and the number of layer boundaries are *** blocks of Modave sandstone are used to prepare *** layer thickness is different among the various blocks,but the layer thickness in each studied rock block can be considered to be constant;hence,the number of layer boundaries changes according to the sample diameter for samples of the same *** experimental study shows that the layer thickness plays a more important role than the number of layer boundaries per sample.

关键词： Layered sandstone Brazilian test Fracture pattern Layer activation shape effect

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Coal Science & Engineering(China) 2007年第3期13卷 348-351页

作者：陈绍杰郭惟嘉杨永杰 Key Laboratory of Mine Disaster Prevention and Control Shandong University of Science and Technology Qingdao 266510 China

The uniaxial compression tests of cylinder standard specimens and different dimension cube specimens of No.13 coal seam of Jianxin Colliery were carried out using MTS, and the basic mechanics parameters of Jianxin Colliery 13 coal were studied. The dimension-form effect of uniaxial compression strength was analyzed. The exponent formula σc=6.928＋130.269 8 exp（-0.105 95D）of dimension effect was fitted. While the side length of specimen reaches 80 mm, its unaxial strength tends to a stable value which is called to be the strength of coal mass. Studies indicates that since the cube specimen suffered more shake than the cylinder one during machining and processing and the stress is centralized at four corners of cube during compressive experiment, the coal strength of standard cylinder specimen is higher than that of cube one.

关键词： uniaxial compression test compressive strength shape effect size effect