GRAPHICAL SOLUTION OF MULTISTAGE FLUIDIZED BED HEAT EXCHANGER

The design of multistage fluidized beds for heat exchange necessitates the solution of the mass and energy balance equations combined with the equilibrium relations for each stage. This paper presents a novel way of applying well known methodology to a different technology, one where it has not been widely applied.

In the present work a McCabe-Thiele type of graphical approach is presented for both counter-current and cross-current contacting multiple fluidized beds. The necessary equations for a multistage calciner are developed and the application of the proposed method is demonstrated. Generalized fluidized bed efficiency for counter-current and cross-current multiple fluidized bed is presented.     

Inner functions and a pseudo-singular-value decomposition in super-optimal H∞ control

The inner functions and pseudo-singular-value decomposition (PSVD) which arise in super optimal H^∞ control are studied. New properties of non-square inner matrices are derived and a structural inner matrix is defined as an inner matrix with no transmission zeros. The uniqueness properties of the PSVD are derived and structural inner functions are used to characterize particular PSVDs     

一种基于环境变化的树木动态生长仿真模型

研究虚拟植物生长的仿真应用较广.针对数字娱乐领域中用于虚拟场景的植物形态-功能仿真的有限需求,为了提高真实性,提出了一种通用的基于环境变化的虚拟树木动态生长的仿真模型,来仿真各种树木的生长过程.采用L系统描述树木的拓扑结构,结合植物学相关知识,引入了环境因素对树木生长的影响,将树木的生物学特性进行抽象与加权处理,建立了树木生长与光照信息交换的简洁算法.仿真实验结果表明,该模型能较好地反映了环境因素变化对植物生长的影响,较真实地仿真再现了树木的动态生长过程.     

Aspergillus Parasiticus Growth and Aflatoxin Production on Dehydrated Taro

A study was made of Aspergillus parasiticus growth and aflatoxin production on four taro media. The critical equilibrium relative humidity (ERH) for natural mold growth on unsterilized dehydrated taro was 88% at 20°C. However, nontoxigenic A. parasiticus NRRL 1957 did not grow at this ERH on dehydrated raw taro incubated at 20°, 30°, or 40°C. Instead, the growth of A. parasiticus NRRL 1957 on dehydrated taro was optimum at 30°C and an ERH of 96%. Aflatoxin production by toxigenic A. parasiticus NRRL 2999 was investigated on four taro media under optimal growth conditions. Only moderate quantities of aflatoxins were produced by A. parasiticus NRRL 2999 on uncooked dehydrated taro, but cooking or supplementation with peptone stimualted mycelial growth and aflatoxin production slightly. Nevertheless, growth and aflatoxin production on cooked or peptone-supplemented taro media was low.     

Extraction of Mutagens from Chlorinated Poultry Chiller Water

Poultry chiller water (PCW) was used as a model to study the formation of mutagens that can result from chlorinating waters of high organic content. The Ames Salmonella mutagenicity test was used to evaluate solvent extracts of PCW. Pentane gave satisfactory extraction of mutagens without the emulsion problem encountered with dichloromethane, permitting the use of pentane in continuous extractors. Use of thiosulfate to remove residual chlorine in samples resulted in low mutagenicity. Mutagens were formed within minutes of chlorination and continued to change in amount during the next 1-2 hr. Mutagen formation was affected by pH and was proportional to chlorine dosage.     

多楼层钢板剪力墙之耐震设计研究

现有钢板剪力墙耐震设计规范对于多楼层钢板剪力墙边界梁柱的容量设计并无清楚交代,本研究的目的在于研发方便且有效的多楼层钢板剪力墙的耐震分析与容量设计方法。探讨不同原理的钢板剪力墙底层边界柱容量设计法,研究如何避免底层柱顶塑性铰的产生,并以ABAQUS有限元模型证实所提设计方法可以有效地避免柱顶塑性铰的发生,而避免侧向变形集中在底层时的软弱层现象。本研究采用美国洛杉矶市反应谱分别设计了6层以及20层的钢板剪力墙建筑结构,并用结构非线性分析软件PISA3D建立双向板条模型进行非线性时程分析,依SAC计划中20组475年回归期的地震分析统计结果讨论钢板剪力墙结构在强烈地震下的反应。由构架动力分析反应和所估计的最大静态需求比较,可观察到钢板对边界柱的最大累积拉力的静态估计值会随着楼层位置越低时有越高估的趋向。此外,边界梁端的最大剪力在上下层钢板厚度相同处,静态估计值有严重低估的情形发生,因此会造成边界梁端的最大累积剪力静态估计值随着楼层位置越低时有越低估不保守的趋向。最后依时程分析结果给出不同楼层数的钢板剪力墙边界柱轴力需求的估算方式建议,依此建议可设计出安全且经济的边界柱。     

A PROCEDURE FOR EVALUATION OF COMMERCIAL FCC CATALYSTS

Based on the correlations between laboratory units and commercial plants, a procedure has been developed to guide commercial FCC (Fluid Catalytic Cracking) catalysts selection. Examining the operability of catalyst mixtures during catalyst transition period is emphasized. The testing procedure is simple and reliable. A commercially available catalyst and the catalyst currently in use have been compared to demonstrate the applicability of this procedure. The commercial testing has confirmed the reliability of laboratory results. The use of the catalyst evaluated led to a 30% saving in catalyst cost.