Simulating the particle size distribution of rockfill materials based on its statistical regularity

1. Introduction Rockfill has excellent engineering characteristics, such as good compactness, better seepage ability, high density, low sedimentation, high shear strength and so on. So it is widely used in dams, bed of railway and deep foundations[1-2]. Two types of rockfill are commonly used in constructions, that is inartificial rockfill such as gravel and scree, and blasted rockfill, e.g. fragmental stone, macadam and moraine soil. Both types are hetero-geneous mixture composed of numerous …     

Numerical prediction of temperature distribution in thermoset composites during laser curing process

The temperature distribution in the advanced thermoset composite during the laser curing process was predicted with the use of the two-dimensional thermo-chemical model presented in this paper which also gives the governing equations based on the thermal history of the curing process. The finite-difference method was used to get the temperature distribution. This paper also deals with the effect of some factors (such as the winding velocity, the tape thickness and the laser heat source) on the temperature distribution.     

基于Copula函数对二维正态分布中常见认识误区的分析

针对二维正态分布讨论联合分布与边缘分布的关系问题。在对二维正态分布中常见的认识误区进行举例辨析的基础上,借助不同的Copula函数对两个一维正态分布的联合分布进行了多种构造,并对两个正态分布的联合分布为二维正态分布的条件进行了说明。     

测量脱硫活化器内颗粒尺寸分布和颗粒数的PIV技术

颗粒尺寸分布及颗粒数是研究活化器脱硫效率的2个重要参数，本介绍了一种应用颗粒速度图像仪(PIV技术)测量脱硫活化器内颗粒尺寸分布和颗粒数的测量方法．为了提高测量的速度，采用Watersheld算法计算图像中每个颗粒的灰度域值，应用边缘增强滤波算于搜索每个颗粒图像的边缘，并用Freeman位的格式保存搜索结果．基于各个颗粒的Freeman位数据，可以计算出流场中颗粒的尺寸分布及颗粒数．最后给出了实际的测量数据及误差分析．研究结果表明PIV技术将是研究脱硫效率的一种重要的测试手段．     

Evaluation of the effective thermal conductivity of composite polymers by considering the filler size distribution law

We present an empirical model for the effective thermal conductivity （ETC） of a polymer composite that includes dependency on the filler size distribution-chosen as the Rosin-Rammler distribution. The ETC is determined based on certain hypotheses that connect the behavior of a real composite material A, to that of a model composite material B, filled with mono-dimensional filler. The application of these hypotheses to the Maxwell model for ETC is presented. The validation of the new model and its characteristic equation was carried out using experimental data from the reference. The comparison showed that by using the size distribution law a very good fit between the equation of the new model （the size distribution model for the ETC） and the reference experimental results is obtained, even for high volume fractions, up to about 50%.