APPLICATION OF RESPONSE SURFACE METHODOLOGY FOR THE MAXIMIZATION OF CONCORA CRUSH RESISTANCE OF PAPERBOARD

Response surface methodology is often used by researchers in different fields to determine the optimum values for controlled variables to maximize or minimize the response variables. Either maximization or minimization might be necessary depending on the response property. For example, if the response variable represents the yield of a process, maximization could be necessary; on the other hand, if the response variable is the biological oxygen demand (BOD) of an effluent the aim would definitely be minimization

Response surface methodology can be used two ways. It can be applied to the full-scale production or it can be scaled to a laboratory or the pilot plant. When applied to the full-scale production, the method is known as evolutionary operation (EVOP). EVOP is the continuous optimization of a process. The optimum conditions in a production plant can change depending on many factors such as raw material, ambient temperature, and equipment wear. Therefore, controlled variables should be optimized continuously to keep the response variable as close as possible to the maximum or minimum value. Hence, controlled variables are systematically changed around a center point to depict any shift of the response variable from the extreme. A thorough discussion of EVOP is given by Box, Evolutionary Operation: A Method for Increasing Industrial Productivity, Appl. Statist., 6, 81-101 (1957).     

淀粉－丙烯腈接枝共聚物水解产物的非晶态X衍射表征函数

用不同方法制备了淀粉－丙烯腈接枝共聚物水解产物，测定了其Ｘ衍射曲线。用５种非晶态表征函数进行了理论计算，由Ｈｉｎｄｅｌｅｈ多项式得到最好结果。确定了Ｈｉｎｄｅｌｅｈ多项式的结构参数，并用此多项式进行了曲线拟合。     

Response Surface Modeling and Optimization in Multiresponse Experiments Using Seemingly Unrelated Regressions

Response surface methodology (RSM) is widely used for optimizing manufacturing processes and product designs. Most applications of RSM involve several response variables. In a typical RSM study, the experimenter will build an empirical model such as the second-order model to each response and use these models to determine settings on the design variables that produce optimal or at least acceptable values for the responses. In most multiple-response RSM problems, the experimenter fits a model to each response using ordinary least squares (OLS). This article illustrates another estimation technique useful in multiple-response RSM problems, seemingly unrelated regressions (SUR). This technique can be very useful when response variables in a multiple-response RSM problem are correlated. Essentially, SUR produces more precise estimates of the model parameters than OLS when responses are correlated. This improved precision of estimation can lead to a more precise estimate of the optimum operating conditions on the process.     

测量复合材料残余应力场的新方法

本文建立了一维表面光栅衍射光强分布与表面应变之间的理论关系,再利用弹性理论,即可求出材料中的残余应力,从而开拓了残余应力的测试方法;在测试技术方面本方法是在试样表面制作一维表面光栅,在激光束的照射下,形成一列清晰的衍射光斑,当试样背面剥层释放残余应力而发生形变时,引起表面光栅栅距d的变化,反映为放大了一列衍射光斑间距的变化,用电荷耦合器件将光信息快速地转换为电信号,以及A/D转换和微机控制的光信息处理系统,可高精度(m)、快速(s)地测试表面应变和残余应力的定量结果,这是一种测试分析表面应变和残余应力及其之间关系的新方法.      

A REVIEW OF THE MATHEMATICAL APPROACHES TO NONLINEAR GRINDING AND A SUGGESTED GENERAL TREATMENT FOR ENVIRONMENTAL NONLINEARITIES BASED ON THE USE OF INFLUENCE FUNCTIONS

Grinding processes such as rod milling and fine dry ball milling sometimes exhibit nonlinear breakage characteristics. These nonlinearities may be due to either sample heterogeneity which gives an apparent nonlinearity or environmental effects which are truly nonlinear. Previous treatments of both of these types of nonlinearities are reviewed and discussed and a new general treatment is proposed for the latter based on the use of influence functions. This treatment allows for both “shielding” and “cushioning” effects and provides a general framework for treating environmental grinding nonlinearities. Simulated results are given for both types of environmental nonlinearities with the influence function approach and methods of applying the approach are discussed.     

Effects of roller burnishing process parameters on surface roughness of A356/5%SiC composite using response surface methodology

In this study,a simple roller burnishing tool was made to operate burnishing processes on A356/5%SiC metal matrix composite fabricated by electromagnetic stir casting under different parameters.The effects of burnishing speed,burnishing force and number of burnishing passes on the surface roughness and tribological properties were measured.Scanning electron microscopy(SEM) graphs of the machined surface with PCD(insert-10) tool and roller burnished surface with tungsten carbide(WC) roller were taken into consideration to observe the surface finish of metal matrix composites.The mechanical properties(tensile strength,hardness,ductility) of A356/5%SiC metal matrix composites were studied for both unburnished samples and burnished samples.The results revealed that the roller burnished samples of A356/5%SiC led to the improvement in tensile strength,hardness and ductility.In order to find out the effects of roller burnishing process parameters on the surface roughness of A35675%SiC metal matrix composite,response surface methodology(RSM)(Box-Behnken design) was used and a prediction model was developed relevant to average surface roughness using experimental data.In the range of process parameters,the result shows that roller burnishing speed increases,and surface roughness decreases,but on the other hand roller burnishing force and number of passes increase,and surface roughness increases.Optimum values of burnishing speed(1.5 m/s),burnishing force(50 N) and number of passes(2)during roller burnishing of A356/5%SiC metal matrix composite to minimize the surface roughness(predicted1.232 urn) have been found out.There was only 5.03%error in the experimental and modeled results of surface roughness.     

新型分层模型求解非均匀土层轴对称问题

该文通过应用一种新的分层模型求解了剪切模量任意变化的非均匀土层受轴对称荷载时的表面位移沉降。根据任意曲线都可以用一系列连续的直线段来逼近,非均匀土层被分为若干个子层,在每个子层中,假设剪切模量沿厚度方向按线性变化,在子层的界面上剪切模量连续并且等于实际值。应用Hankel积分变换和传递矩阵方法,求解了剪切模量按照不同函数形式变化的表面沉降。     

NEW NUMERICAL INTEGRATION SCHEMES FOR APPLICATIONS OF GALERKIN BEM TO 2-D PROBLEMS

We consider hypersingular integral formulation of some elasticity and potential boundary value problems on 2-D domains. In particular, we consider all integrals whose evaluation is required when the equations are solved by a Galerkin BEM based on piecewise polynomial approximants of arbitrary local degrees. In order to compute these integrals, we use very efficient formulas recently proposed, which require the user to define a mesh, not necessarily uniform, on the boundary and specify the local degrees of the approximant. These rules are quite suitable for the construction of h–p version of the BEM. Implementation of h−, p− and h–p methods are applied to some classical problems and several numerical results are presented. © 1997 by John Wiley & Sons, Ltd.     

复杂机构开环控制逆动力学方程的一种新解法

本文讨论了复杂机构开环控制逆动力学分析的一种新方法。它通过直接设计机构的开环输入，使机构完成给定的运动或跟踪给定的优化轨迹，同时抑制或消除不希望的干扰运动。本文提出了求解所得逆动力学方程的一种较为普遍的解法—模型递推算法，并给出了仿真示例。