Spray-drying of alumina powder for APS: effect of slurry properties and drying conditions upon particle size and morphology of feedstock

In this paper, effects of variables concerning slurry properties and drying conditions on the particle size and morphology of feedstock were discussed. The results indicated that, the increase of powder loading increased D ₅₀ and volume content but reduced recovery rate slightly. Other variables, such as inlet temperature, showed a maximum on the desired property. The particle size of resulting feedstock increased with the rise of feeding rate of slurry, however, decreased with the increase of atomization pressure based on the premise that atomization pressure was enough to force slurry to form the liquid membrane. For preparation of spherical feedstock, optimized variables were as follows: 60 wt.% powder in slurry, 2 wt.% PVA in slurry, inlet temperature of 60°C, atomization pressure of 13 × 10³ KPa and feeding rate of 12 ml min^?1. The volume content of feedstocks with 10–45 μm was above 65% and for D ₅₀ it was 15·42 μm. In addition, according to the heat and mass transfer equation, the drying mechanism was established, which was well in agreement with the experimental results.     

On the interdependency of primary and initial secondary equilibrium paths in sensitivity analysis of elastic structures

The scientific motivation for this paper is lack of clarity about the interdependency of primary and initial secondary equilibrium paths in the frame of sensitivity analysis of elastic structures. The investigation of this interdependency comprises of the following four cases: (1) nonlinear primary path, nonlinear stability problem, (2) linear primary path, nonlinear stability problem, (3) nonlinear primary path, linear stability problem, and (4) linear primary path, linear stability problem. The consistently linearized eigenproblem is used for differentiation of two classes of nonlinear stability problems with markedly different characteristics of both the prebuckling and the postbuckling behavior. For one of them, e.g. zero-stiffness postbuckling is impossible. For the other one, which is restricted to a prebuckling regime with axial deformations only, sensitivity analysis of the initial postbuckling behavior either exhibits its continuous improvement or its continuous deterioration, depending on whether the bifurcation point diverges from or converges to the snap-through point. In other words, a monotonic variation of the design parameter cannot result in a non-monotonic change of the initial postbuckling behavior. The practical motivation for this work is to explore the mechanical reasons for qualitatively different modes of transition from imperfection sensitivity to insensitivity in the course of sensitivity analysis for the purpose of improving the postbuckling behavior of structures by means of minor design changes. Results from a numerical investigation corroborate the theoretical findings.     

短纤维链板式松弛热定型机流场的研究

分析了链板式松弛热定型机的结构及运行特点;通过对链板式松弛热定型机的冷态测试实验,获得了热定型机内部流场气流的速度分布数据,以探讨热定型机内部流场的特点。结果表明:在纤维层上部存在着明显的气流不均匀现象,匀风板上部具有高速气流区;指出热定型风板开孔不合理,导致纤维层上部气流分布不均匀,气流短路使得散热器下部流场分布不均匀;提出改善热定型机匀风板的开孔率,可实现均匀布风的初步方案。     

挤出机双流道筒体的设计及换热能力的计算与分析

介绍了设计双流道筒体的必要性,通过建立物理、数学模型详细论述了双流道筒体的设计原理及换热计算过程,并通过试验对比分析验证了模型的可靠性,同时对单、双流道筒体的换热能力进行对比分析,得出了可靠的结论.     

PLC过程控制故障分析与排除

在分析PLC过程控制的故障特点的基础上,通过实例,介绍了4种故障分析与排除的方法。     

托辊轴承系列产品塑料保持架的改进

托辊轴承应用于煤矿带式输送机和农业带式输送机中,其轴承工作环境恶劣,灰尘大,在煤泥水和其他有害的气体环境中运转。因此,托辊轴承对旋转阻力、防卡寿命具有一定的要求。为满足托辊轴承性能要求,首先在保持架的材料选取及保持架结构设计上进行了改进。保持架的材质采用了性能优良的工程塑料,并在保持架的结构上进行了改进-增加了叶片。因此,提高了轴承的寿命及动态性能。     

山水交融,生态校园——湖南潇湘技师学院新校区方案设计

该文通过对湖南潇湘技师学院新校区规划设计方案的分析介绍,阐述了校园建筑应以人为本,与生态环境相融合。同时为现代新校园的设计提出创造性的理念。     

Seeker optimization algorithm for global optimization: A case study on optimal modelling of proton exchange membrane fuel cell (PEMFC)

In order to optimize the proton exchange membrane fuel cell (PEMFC) model parameters, a novel approach based on seeker optimization algorithm (SOA) is proposed. The SOA is based on the concept of simulating human searching behaviors, where the choice of search direction is based on the empirical gradient by evaluating the response to the position changes and the decision of step length is based on uncertainty reasoning by using a simple Fuzzy rule. In this study, after evaluated on benchmark function optimization, the SOA is applied to optimal modelling of the PEMFC by using a fuel cell test system in Fuel Cell Application Centre (FAC) at the Temasek Polytechnic, and compared with several state-of-the-art versions of differential evolution (DE) and particle swarm optimization (PSO) algorithms. The simulation results show that the proposed approach is superior to other compared algorithms, and the PEMFC model with optimized parameters by SOA fitted experimental data well. Hence, SOA is an effective and reliable technique for optimizing the parameters of PEMFC model, and can be helpful for system analysis, optimization design and real-time control of the PEMFCs.     

智能用电小区中通信平台建设研究

通信技术是实现智能用电小区信息双向互动的重要基础支撑。分析了智能用电小区的通信需求,以上海世博园智能电网综合示范工程中的智能用电试点小区建设情况为例,介绍了试点小区的构架及实现方式,研究了目前智能用电小区通信平台存在的问题并进行展望。     

基于自适应加权融合的标准铜柱鉴选研究

介绍了标准铜柱在塑性测压校准系统的重要作用及其鉴选方法。为提高测压铜柱受压后变形量测量准确性,提出了用自适应加权融合算法应用于变形量的融合计算,利用所提供的数据融合出标准偏差最小的数据融合值,以3.5×8.75、4×6.5、8×13测压铜柱实测数据为例,比较分析了各型号铜柱采用自适应加权融合算法与平均估算法、贝赛尔公式计算法的有效性和融合精度的差异,从理论和实践两个方面验证了该方法的有效性,提高了融合精度。