Copper(II) removal from aqueous solutions by fly ash

The removal of Cu(II) by adsorption on fly ash has been found to be concentration, pH and temperature dependent. The kinetics of adsorption indicates the process to be diffusion controlled. The Langmuir constants have been calculated at different temperatures, and the adsorption has been found to be endothermic (ΔH = 15.652 kcal mol^?1). The maximum removal is observed at pH 8.0, and variation in adsorption with pH has been explained on the basis of surface ionisation and complexation.     

正压冲固基础海洋平台冰激振动动力响应

正压冲固基础海洋平台是一种新型平台桩基结构形式。采用三维有限元的数值分析方法,建立了正压冲固平台的三维有限元模型。基于冰激强迫振动理论提出动冰载荷的计算方法,根据海冰破碎长度和冰速确定冰载周期,冰强度限制的水平冰力作为冰力峰值,得到的动冰载荷用于正压冲固平台的动力响应分析,并依照规范计算了6倍桩径处刚性固定时的动力响应。三维有限元方法计算得到的动力响应大于6倍桩径刚性固定时的计算结果,结构安全性评估偏于安全。     

Simulation by Slepian method of plastic displacements of Gaussian process excited multistory shear frame

The object of study is a stationary Gaussian white noise excited multi-degree-of-freedom (MDOF) linear elastic, ideal plastic, linearly damped, statically determinate oscillator with several potential elements of ideal plastic yielding. Specifically the study is exemplified for a plane multistory shear frame with rigid traverses where all the connecting columns except the columns in one or more of the bottom floors have finite symmetrical yield limits. The white noise excitation acts on the mass of the first floor making the movement of the elastic bottom floors simulate a ground motion that interacts with the structure above the bottom floors. The method of study is so-called Slepian model simulation and is in principle the same for other statically determinate MDOF elasto-plastic oscillators of the considered type. The method is fast as compared to direct simulation and provides results that give good insight in the behavior of the plastic displacement response process.     

甲基丙烯酸三氟乙酰氧乙酯的聚合

对甲基丙烯酸三氟乙酰氧乙酯(TFAOEMA)的阴离子聚合及原予转移自由基聚合进行了研究。常用的阴离于引发剂如丁基锂、1，1-二苯基已基锂等很难引发TFAOEMA的阴离子聚合，而碱性较弱的引发剂如三乙基铝却容易引发，且产率较高。以氯化亚铜、五甲基二乙基三胺、溴代丙酸乙酯为引发体系的TFAOEMA的本体原子转移自由基聚合符合活性聚合特征。但在四氢呋喃为溶剂的原子转移自由基聚合中却存在活性中心失活现象。以末端含卤素的聚甲基丙烯酸甲酯为大分子引发剂，引发TFAOEMA的原子转移自由基聚合，得到了含氟双嵌段聚合物。     

Influence of the Transport Properties of the Crystal/Heat Transfer Surface Interfacial on Fouling Behavior

One method to reduce fouling is to extend the induction time by a defined modification of the interfacial interactions between the heat transfer surface and the crystalline deposit. Since these interactions are a result of both molecular and mechanical forces, two approaches for fouling mitigation have been developed: (a) Modification of the energy related properties of the heat transfer surface and (b) Modification of the geometry related properties of the heat transfer surface.     

Dynamic stiffness vibration analysis using a high‐order beam model

This work presents the derivation of the exact dynamic stiffness matrix for a high‐order beam element. The terms are found directly from the solutions of the differential equations that describe the deformations of the cross‐section according to the high‐order theory, which include cubic variation of the axial displacements over the cross‐section of the beam. The model has six degrees of freedom at the two ends, one transverse displacement and two rotations, and the end forces are a shear force and two end moments. Using the dynamic stiffness matrix exact vibration frequencies for beams with various combinations of boundary conditions are tabulated and compared with results from the Bernoulli–Euler and Timoshenko beam models. Copyright © 2003 John Wiley & Sons, Ltd.     

Significance of fluid regime in biological filtration

A dispersed flow model previously developed to study substrate utilization in unsaturated media was experimentally verified and its practical application was considered. For this purpose, measurements were made using tap water and a synthetic feed solution. The importance of the change in fluid regime as regards to the simultaneous transport and reaction within biological filters were demonstrated. The effect of drop formation and the breakage of liquid jets inside the filters on substrate utilization was also shown.     

Temperature Oscillation Calorimetry: Robustness analysis of different algorithms for the evaluation of the heat transfer coefficient

Applicability of different temperature oscillation calorimetry algorithms, previously proposed in the literature, for the evaluation of the heat transfer coefficient during the course of the reaction, is analysed by referring to the experimental data from a methyl methacrylate polymerisation reactor.Results are coincident in the nominal case (no errors on data), while differences appear in the elaboration of real data. The effect of uncertainty in the experimental data has been simulated in terms of error on the amplitude and on the phase of reactor and jacket temperature profiles.This approach allows to indicate algorithms having the best robustness properties and to give an explanation of phase errors in terms of a lumped parameter which accounts for different phenomena, not included in the basic hypotheses of the method. Based on this observation, a procedure to eliminate this source of errors from experimental data is proposed for the more general algorithm presented to handle oscillating temperature profiles generated by different techniques.     

Transient operation of a catalytic liquid-liquid plug flow reactor for kinetics measurements

A centrifugal partition chromatograph (CPC) was used as a liquid-liquid catalytic reactor for the isomerisation of hexen-3-ol into ethylpropylketone with a water soluble rhodium catalyst. Global mass transfer coefficients were measured and shown to depend on both the nature of the solute and the flow rate. Liquid-liquid partition isotherms were also determined with the CPC using elution chromatography. Finally, a reactor model was derived to account for the experimental results obtained both under stationary and transient (pulse) conditions. A parameter sensitivity evaluation is also presented.