检索结果-南通市图书馆

Anthropometrics and electromyography as predictors for maximal voluntary isometric arm strength

Journal of Sport and Health Science 2012年第2期1卷 107-113页

作者： Lara A.Green David A.gabriel Department of Kinesiology Brock UniversitySt.CatharinesON L2S 3A1Canada

Background:Muscular strength can be conceptually determined by two components:muscle activation and *** activation by the central nervous system can be measured by surface electromyography(sEMG).Muscular size reflects the amount of contractile protein within a skeletal muscle and can be estimated by anthropometric *** purpose of this study was to determine the relative contributions of size parameters and muscle activation to the prediction of maximal voluntary isometric elbow flexion strength. Methods:A series of anthropometric measurements were taken from 96 *** and root-mean-square(RMS) of the sEMG from the biceps brachii were averaged across three maximal voluntary isometric contractions.A multiple linear regression analysis was performed based on a Pearson's correlation matrix. Results:Body weight(BW) accounted for 39.1% and 27.3% in males and females,respectively,and was the strongest predictor of strength for *** length(L3) was the strongest predictor of strength in females(partial R^2 = 0.391).Elbow circumference(ELB) accounted for a significant(p < 0.05) amount of variance in males but not *** addition of sEMG RMS as a third variable accounted for an average of 10.1% of the variance excluding the equation of BW and L3 in *** strongest prediction equation included BW,L3,and ELB accounting for 55.6% and 58.5% of the variance in males and females,respectively. Conclusion:Anthropometrics provide a strong prediction equation for the estimation of isometric elbow flexion *** activation,as measured by sEMG activity,accounted for a significant(p < 0.05) amount of variance in most prediction equations,however,its contribution was comparable to an additional anthropometric variable.

关键词： Biceps brachii Biomechanics Gender differences Multiple linear regression Muscle force

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A POSTERIORI ERROR ANALYSIS OF A FULLY-MIXED FINITE ELEMENT METHOD FOR A TWO-DIMENSIONAL FLUID-SOLID INTERACTION PROBLEM

引用

Journal of Computational Mathematics 2015年第6期33卷 606-641页

作者： Carolina Dominguez gabriel N. Gatica salim meddahi Instituto de Ciencias Fisicas y Matemdticas facultad de ciencias universidad austral de chile Avenida Eduardo Morales Miranda - Campus isla teja valdivia chile CI2 MA and Departamento de Ingenieria Matematica Universidad de concapcion casilla 160 concepcion chile Departamento de Matemdticas Facultad de ciencias universidad de oiede calvo satela s/n oviedo espana

In this paper we develop an a posteriori error analysis of a fully-mixed finite element method for a fluid-solid interaction problem in 2D. The media are governed by the elas-todynamic and acoustic equations in time-harmonic regime, respectively, the transmission conditions are given by the equilibrium of forces and the equality of the corresponding normal displacements, and the fluid is supposed to occupy an annular region surrounding the solid, so that a Robin boundary condition imitating the behavior of the sommerfeld condition is imposed on its exterior boundary. Dual-mixed approaches are applied in both domains, and the governing equations are employed to eliminate the displacenent a of the solid and the pressure p of the fluid. In addition, since both transmission conditions become essential, they are enforced weakly by means of two suitable lahrange multipliers The unknowns of the solid and the fluid are then approximated by a conforming galerkin scheme defined in terms of PEERS elements in the solid, Raviart-Thomas of lowest order in the fluid, and continuous piecewise linear functions on the boundary, As the main con-tribution of this work, we derive a reliable and efficient residual-based a posteriori error estimator for the aforedescribed coupled problem. Some numerical results confirming the properties of the estimator are also reported.

关键词： Mixed finite elements Helmholtz equation Elastodynamic equation A poste- riori error analysis

来源：

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

A Transmission and Transformation Fault Detection Algorithm Based on Improved YOLOv5

引用

Computers, Materials & Continua 2023年第9期76卷 2997-3011页

作者： Xinliang Tang Xiaotong Ru Jingfang Su gabriel Adonis School of Information Science and Engineering Hebei University of Science and TechnologyShijiazhuang050000China Department of Computer Science and Information Systems Birkbeck Institute for Data AnalyticsLondonB100ABWC1E 7HXUK

On the transmission line,the invasion of foreign objects such as kites,plastic bags,and balloons and the damage to electronic components are common transmission line *** these faults is of great significance for the safe operation of power ***,a YOLOv5 target detection method based on a deep convolution neural network is *** this paper,Mobilenetv2 is used to replace Cross Stage Partial(CSP)-Darknet53 as the *** structure uses depth-wise separable convolution to reduce the amount of calculation and parameters;improve the detection *** the same time,to compensate for the detection accuracy,the Squeeze-and-Excitation Networks(SENet)attention model is fused into the algorithm framework and a new detection scale suitable for small targets is added to improve the significance of the fault target area in the *** pictures of foreign matters such as kites,plastic bags,balloons,and insulator defects of transmission lines,and sort theminto a data *** experimental results on datasets show that themean Accuracy Precision(mAP)and recall rate of the algorithm can reach 92.1%and 92.4%,*** the same time,by comparison,the detection accuracy of the proposed algorithm is higher than that of other methods.

关键词： Transmission line YOLOv5 multi-scale integration SENet

来源：

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

Tensor Tomography: Progress and Challenges

引用

Chinese Annals of Mathematics,Series B 2014年第3期35卷 399-428页

作者： gabriel P. PATERNAIN Mikko SALO Gunther UHLMANN Department of Pure Mathematics and Mathematical Statistics University of Cambridge Department of Mathematics and Statistics University of Jyvskyl Department of Mathematics University of Washington and University of HelsinkiBox 354350 Seattle Washington 98195-4350 USA

The authors survey recent progress in the problem of recovering a tensor field from its integrals along geodesics. Several open problems are also proposed.

关键词： Inverse problem Integral geometry Tensor tomography

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling particle sedimentation in viscous fluids with a coupled immersed boundary method and discrete element method

引用

Particuology 2017年第2期15卷 191-199页

作者： Sayed M. Derakhshani Dingena L. Schott gabriel Lodewijks Faculty of Mechanical Maritime and Materials Engineering Delft University of Technology Delft Netherlands Department of Mechanical Engineering Faculty of Engineering University of Isfahan Isfahan Iran

Numerical techniques have increasingly been used to model fluid–particle two-phase flows. Coupling the immersed boundary method （IBM） and discrete element method （DEM） is one promising approach for modeling particulate flows. In this study, IBM was coupled with DEM to improve the reliability and accuracy of IBM for determining the positions of particles during the sedimentation process within viscous fluids. The required ratio of the particle diameter to the grid size （D/dx） was determined by comparing the simulation results with the analytical solution and experimental data. A dynamic mesh refinement model was utilised in the IBM model to refine the computational fluid dynamics grid near the particles. In addition, an optimum coupling interval between the IBM and DEM models was determined based on the experimental results of a single particle sedimentation within silicon oil at a Reynolds number of 1.5. The experimental results and the analytical solution were then utilised to validate the IBM–DEM model at Reynolds numbers of 4.1, 11.6, and 31.9. Finally, the validated model was utilised to investigate the sedimentation process for more than one particle by modeling the drafting-kissing-tumbling process and the Boycott phenomenon. Benchmark tests showed that the IBM–DEM technique preserves the advantages of DEM for tracking a group of particles, while the IBM provides a reliable and accurate approach for modeling the particle–fluid interaction.

关键词： Immersed boundary method Discrete element method Particle sedimentation Boycott phenomenon

来源：

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

OPTIMAL ERROR ESTIMATES FOR NEDELEC EDGE ELEMENTS FOR TIME-HARMONIC MAXWELL'S EQUATIONS

引用

Journal of Computational Mathematics 2009年第5期27卷 563-572页

作者： Liuqiang Zhong Shi Shu gabriel Wittum Jinchao Xu School of Mathematical and Computational Sciences Xiangtan University Xiangtan 411105 China Simulation and Modelling Goethe- Center for Scientic Computing Goethe-University Kettenhofweg 139 60325 Frankfurt am Main Germany Department of Mathematics Pennsylvania State University University Park PA 16802 USA

In this paper, we obtain optimal error estimates in both L^2-norm and H（curl）-norm for the Nedelec edge finite element approximation of the time-harmonic Maxwell＇s equations on a general Lipschitz domain discretized on quasi-uniform meshes. One key to our proof is to transform the L^2 error estimates into the L^2 estimate of a discrete divergence-free function which belongs to the edge finite element spaces, and then use the approximation of the discrete divergence-free function by the continuous divergence-free function and a duality argument for the continuous divergence-free function. For Nedelec＇s second type elements, we present an optimal convergence estimate which improves the best results available in the literature.

关键词： Edge finite element Time-harmonic Maxwell's equations.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Laboratory study and predictive modeling for thaw subsidence in deep permafrost

引用

Research in Cold and Arid Regions 2021年第2期13卷 95-106页

作者： ZhaoHui Joey Yang gabriel TPierce University of Alaska Anchorage AnchorageAlaskaUSA

Oil wells on the North Slope of Alaska pass through deep deposits of permafrost. The heat transferred during their operation causes localized thawing, resulting in ground subsidence adjacent to the well casings. This subsidence has a damaging effect, causing the casings to compress, deform, and potentially fail. This paper presents the results of a laboratory study of the thaw consolidation strain of deep permafrost and its predictive modeling. Tests were performed to determine strains due to thaw and post-thaw loading, as well as soil index properties. Results, together with data from an earlier testing program, were used to produce empirical models for predicting strains and ground subsidence. Four distinct strain cases were analyzed with three models by multiple regression analyses, and the best-fitting model was selected for each case. Models were further compared in a ground subsidence prediction using a shared subsurface profile. Laboratory results indicate that strains due to thaw and post-thaw testing in deep core permafrost are insensitive to depth and are more strongly influenced by stress redistributions and the presence of ice lenses and inclusions. Modeling results show that the most statistically valid and useful models were those constructed using moisture content, porosity, and degree of saturation. The applicability of these models was validated by comparison with results from Finite Element modeling.

关键词： deep permafrost thaw consolidation strain predictive models multiple regression analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fluidization of binary mixtures of sisal residue and sand:A new model for deriving the final fluidization velocity

引用

Particuology 2018年第5期16卷 10-22页

作者： David Vasconcelos gabriele Batalha Luis gabriel Pereira Carlos Augusto Pires Chemical Reaction Engineering Laboratory Federal University of Bahia40.210-910SalvadorBABrazil

The influence of different factors on the fiuidization of a binary mixture of sisal residue and sand was *** particle sizes of the sand and sisal residue were varied from 0.2to 0.8mm and the biomass mass fractions from 2% to 9%.Some segregation was noted,and a significant relationship was found among the final fluidization velocity (Uff),the biomass and sand sizes,and the biomass mass fraction.A novel model was developed for predicting Uff,leading to an average discrepancy of 12.69% between the measured and predicted Uff compared with the best match of 15.32% when using a model from a previous *** new model was applied to data from studies using other biomass and a broad range of particle *** average divergences from measured values when using the new model were 7.9% for corn cob and walnut shell,and 20.5% for sweet sorghum bagasse,tobacco residue, and soy *** were superior to the values derived using other *** results confirm the accuracy of the model developed in this work and show that it represents a viable alternative way to calculate Uff for a binary mixture of sand and biomass.

关键词： Fluidization Binary mixture Sisal residue Final fluidization velocity model

来源：

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

Experimental and numerical study of pseudo-2D circulating fluidized beds

引用

Particuology 2016年第6期14卷 48-59页

作者： Adam Klimanek Wojciech Adamczyk Sirpa Kallio Pawet Kozolub gabriel Wecel Institute of Thermal Technology Silesian University of TechnologyKonarskiego 22 44-100 Gliwice Poland Technical Research Centre of Finland Ltd P.O. Box 1000 FI-02044 VTT Finland Amec Foster Wheeler Staszica 31 41-200 Sosnowiec Poland

We present experimental investigations and numerical simulations of a pseudo-2D riser. Experiments were performed for various airflow rates, particle types/diameters, and particle size distributions. Pres- sure distributions along the wall of the riser were measured, Additional measurements from a smaller pseudo-2D riser （Kallio et al., 2009; Shah et al., 2012） were used to analyze horizontal solids volume fraction profiles. The experimental data were compared with simulation results carried out using an Euler-Euler approach, A mesh sensitivity study was conducted for numerical simulations and effects associated with simplifying real 3D geometry to a 2D model were examined. In addition, the effect of using an algebraic equation to represent the granular temperature versus a full partial differential equation also was examined for numerical simulations. Results showed small but significant near-wall sensitivity of the flow variables to mesh size. Substantial differences in mean pressure, solids distribution, and solid velocities were obtained, when 2D and 3D simulation results were compared. Finally, applying the simplified granular temperature equation for turbulent fluidization and for dilute-phase transport can lead to incorrect predictions in models,

关键词： Circulating fluidized bed Euler-Euler approachGas-solid flow Kinetic theory of granular flow Particle size distribution 2D vs 3D

来源：

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

Fuzzy logic controller implementation on a microbial electrolysis cell for biohydrogen production and storage

引用

Chinese Journal of Chemical Engineering 2021年第12期34卷 149-159页

作者： gabriel Khew Mun Hong Mohd Azlan Hussain Ahmad Khairi Abdul Wahab Department of Chemical Engineering Faculty of EngineeringUniversiti Malaya50603 Kuala LumpurMalaysia Department of Biomedical Engineering Faculty of EngineeringUniversiti Malaya50603 Kuala LumpurMalaysia Centre for Separation Science and Technology(CSST) Faculty of EngineeringUniversiti Malaya50603 Kuala LumpurMalaysia

This work presents the implementation of fuzzy logic control(FLC) on a microbial electrolysis cell(MEC).Hydrogen has been touted as a potential alternative source of energy to the depleting fossil fuels. MEC is one of the most extensively studied method of hydrogen production. The utilization of biowaste as its substrate by MEC promotes the waste to energy initiative. The hydrogen production within the MEC system, which involves microbial interaction contributes to the system's nonlinearity. Taking into account of the high complexity of MEC system, a precise process control system is required to ensure a wellcontrolled biohydrogen production flow rate and storage application inside a tank. Proportionalderivative-integral(PID) controller has been one of the pioneer control loop mechanism. However, it lacks the capability to adapt properly in the presence of disturbance. An advanced process control mechanism such as the FLC has proven to be a better solution to be implemented on a nonlinear system due to its similarity in human-natured thinking. The performance of the FLC has been evaluated based on its implementation on the MEC system through various control schemes progressively. Similar evaluations include the performance of Proportional-Integral(PI) and PID controller for comparison purposes. The tracking capability of FLC is also accessed against another advanced controller that is the model predictive controller(MPC). One of the key findings in this work is that the FLC resulted in a desirable hydrogen output via MEC over the PI and PID controller in terms of shorter settling time and lesser overshoot.

关键词： Fuzzy logic control Process control Nonlinear Microbial electrolysis cell Renewable energy Hydrogen

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：