Dynamics of Flexible Multibody Systems Using Virtual Work and Linear Graph Theory

By combining linear graph theory with the principle of virtualwork, a dynamic formulation is obtained that extends graph-theoreticmodelling methods to the analysis of flexible multibody systems. Thesystem is represented by a linear graph, in which nodes representreference frames on rigid and flexible bodies, and edges representcomponents that connect these frames. By selecting a spanning tree forthe graph, the analyst can choose the set of coordinates appearing inthe final system of equations. This set can include absolute, joint, orelastic coordinates, or some combination thereof. If desired, allnon-working constraint forces and torques can be automaticallyeliminated from the dynamic equations by exploiting the properties ofvirtual work. The formulation has been implemented in a computerprogram, DynaFlex, that generates the equations of motion in symbolicform. Three examples are presented to demonstrate the application of theformulation, and to validate the symbolic computer implementation.     

Kinematic analysis of 3SPS+1PS bionic parallel test platform for hip joint simulator based on unit quaternion

As a novel parallel hip joint simulator, the 3SPS+1PS bionic parallel test platform with 4 degrees of freedom including three rotations and one translation is proposed. SPS denotes the spherical-prismatic-spherical leg and PS denotes the prismatic-spherical leg where only the prismatic joint is actuated and hence underlined. By means of the unit quaternion method, the formulae for solving the inverse/forward displacement, the inverse/forward velocity and the inverse/forward acceleration kinematics are derived. Using the unit quaternion to represent the position and orientation of a moving platform, singularities caused by Euler angles can be avoided. Combining the topological structure characteristics of the 3SPS+1PS bionic parallel test platform and letting the three-dimensional (3-D) motion of a human hip joint as its output movement, the displacement trajectories of three active legs are constructed based on the inverse displacement kinematics. The forward kinematic tests whose data are recorded by a 3-D orientation capture system are carried out on the developed parallel hip joint simulator. Moreover, the results of the forward kinematic tests prove that the 3SPS+1PS bionic parallel test platform can approximately represent human hip joint motion and provide more reliable experimental data for hip joint prostheses in clinical application.     

Physiological responses to simulated firefighter exercise protocols in varying environments

For decades, research to quantify the effects of firefighting activities and personal protective equipment on physiology and biomechanics has been conducted in a variety of testing environments. It is unknown if these different environments provide similar information and comparable responses. A novel Firefighting Activities Station, which simulates four common fireground tasks, is presented for use with an environmental chamber in a controlled laboratory setting. Nineteen firefighters completed three different exercise protocols following common research practices. Simulated firefighting activities conducted in an environmental chamber or live-fire structures elicited similar physiological responses (max heart rate: 190.1 vs 188.0 bpm, core temperature response: 0.047°C/min vs 0.043°C/min) and accelerometry counts. However, the response to a treadmill protocol commonly used in laboratory settings resulted in significantly lower heart rate (178.4 vs 188.0 bpm), core temperature response (0.037°C/min vs 0.043°C/min) and physical activity counts compared with firefighting activities in the burn building.

Practitioner Summary: We introduce a new approach for simulating realistic firefighting activities in a controlled laboratory environment for ergonomics assessment of fire service equipment and personnel. Physiological responses to this proposed protocol more closely replicate those from live-fire activities than a traditional treadmill protocol and are simple to replicate and standardise.     

模拟抗原（Ac-NK16-Ahx-3）免疫反应抗体ELISA检测方法研究

为满足实验室单克隆抗体的制备研究,本实验特对实验室常用的制备单抗的模拟抗原（Ac-NK16-Ahx-3）进行ELISA间接法检测,进而建立一种高效的检测方法。通过对不同稀释度待测抗体的免疫吸附测定,检测出它的最终灵敏度为0.078mg/mL,最佳二抗稀释倍数为300倍,其最佳拟合曲线为y=-0.0732x＋0.6875,R2=0.8619。并且,通过统计学方法进行统计分析,确定出各实验组的相关性及变异系数,从而排除实验中的操作误差,最终可确定最佳的实验条件,并保证实验的准确性。     

Model test of helical angle effect on coal loading performance of shear drum

The work presented in this paper focuses on improving coal loading performance of shear drum.Employing the similarity theory,we carried out a dimensional analysis of the correlation parameters which in...     

广东省电网建设与经济发展关系实证研究

以广东省1993--2011年相关时间序列数据为基础,建立了反映电网建设水平与社会经济发展关系的向量自回归（VAR）模型,在VAR模型的基础上,分析了广东省电网建设指标与社会经济发展指标的格兰杰因果关系,运用脉冲响应函数和方差分解方法分析了电网建设与社会经济发展之间的动态影响。研究结果表明,电网建设是经济增长的基础条件之一,在电网建设与经济增长的相互作用中,电网建设对经济增长的促进作用更为显著。     

基于虚拟实训基地（车间）的工学结合人才培养模式研究

为了寻求适合自身的人才培养模式,分析了当前国内高等职业教育人才培养模式的现状,提出了基于虚拟实训基地（车间）的工学结合人才培养模式;从校内实训基地建设、课程体系与学习领域开发、教学模式和＂双师型＂教师培养等四个方面阐述了该人才培养模式的具体内容和切实可行性。     

Round-Robin Test on methods for determining chloride transport parameters in concrete

This paper presents the results of a Round-Robin Test on methods for determining chloride transport parameters in concrete, carried out by the Technical Committee TC 178-TMC: “Testing and Modelling Chloride Penetration in Concrete” in which 27 different laboratories around the world have participated, using 13 different methods, in triplicate specimens, for 4 different mixes of concrete cast with different binders. Four different groups of methods have been tested: Natural diffusion methods (D), Migration methods (M), Resistivity methods (R) and Colourimetric methods (C). The statistical treatment of the data has been carried out according to the International Standard ISO 5725-2:1994 for the determination of the accuracy (trueness and precision) of measurement methods and results. Part 2: Basic method for the determination of the repeatability and reproducibility of a standard measurement method. In order to make an evaluation of these methods, four indicators have been identified and within each of them, several sub-indicators have been assigned. According to this system of classification, the methods have been classified following each indicator (trueness, precision, relevance and convenience), and also globally, by assigning different factors of importance, F.I., to the different indicators.     

Leakage tests for Am solid sources used for liquid xenon detector monitoring

Experimental tests are described to check solid ²⁴¹Am radioactive sources used to monitor operation of liquid xenon detectors. In particular, radioactive leakage was tested in extreme temperature conditions following immersion in liquid nitrogen for different time periods. No radioactivity loss was detected from the sources considered. The paper describes the source characteristics, test methods and results obtained.