Modelling and optimisation of a transketolase-mediated carbon-carbon bond formation reaction

In this paper, we have integrated process characterisation and reaction kinetic data for a transketolase catalysed carbon-carbon bond formation to build a comprehensive reaction model. Based on the synthesis of erythrulose from β-hydroxypyruvate and glycolaldehyde, the model includes component degradation as a function of time and concentration as well as glycolaldehyde toxicity towards the enzyme. Using the ratio of initial substrate concentration as a process variable, simulations and analysis based on this model allowed process options to be evaluated. The model links bioconversion to upstream fermentation for enzyme production and downstream product purification and this could provide guidelines for process development.     

轻型输送带的发展现状

简要介绍了轻型带的发展现状，重点说明了轻型带的结构特点、分类、标志方法以及轻型带的生产工艺路线、输送形式，并介绍了该产品在现代工业物料输送中具有广泛的使用前景。     

富马酸生产工艺进展

笔者通过对国内外富马酸生产工艺的比较，讨论分析了影响富马酸生产经济效益和产品质量的因素，提出根据建厂厂址自然条件和投资情况，合理选择工艺路线、设备、工艺参数的依据。     

利用α-甲基苯乙烯合成佳乐麝香的研究

介绍一种新的佳乐麝香合成方法，并就反应的参数对反应过程的影响进行了探讨。     

Preparation of nano-sized silicon carbide powder using thermal plasma

Nano-sized silicon carbide (SiC) powder was prepared by thermal plasma process using silicon tetrachloride (SiCl₄) and methane (CH₄). The synthesized powder was characterized by X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy, FT-IR spectroscopy and particle size analyzer. The powder was dominated by β-SiC including some of α-SiC and free carbon species. The quality of the powder was varied with process conditions such as the molar ratio of H/Si and C/Si, and collecting positions. It was known that the conversion to SiC was mainly affected by the addition of hydrogen gas because it promoted the decomposition and reduction of SiCL. CH₄ was easily decomposed to carbon species for the formation of SiC as well as removal of impure oxygen, but excessive carbon suppressed the formation of crystalline SiC and resulted in the solid carbon contamination. The optimum ratio of H/Si was approx. 26 and that of C/Si was 1.1. For collecting positions, the powder collected at the vessel and filter was preferable to that at the reaction tube. The average size of the powder synthesized was estimated to be below 100 nm and uniform in distribution.     

“工作室”制的图形图像制作专业人才培养模式的思考

近些年来,伴随着素质教育在各个高校以及职业学校普及的大趋势。以及社会上的各个集团公司和部门对公司工作人员综合素质的需求的目益增加,如何培养除具备高素质的人才已经成为了摆在各个职业学校面前的大难题。截至目前为止。为了响应国家职业教育高速发展的大趋势也是为了提升自己学生的综合职业素养能力,各个高等职业学校纷纷推行了一种新型的人才培养模式——工作室培养人才的新型人才培养机制。“工作宣”教育制度的培育模式是在教育教学的过程之中大力提倡实践教育,不是以前的传统的只注重考试成绩的教育,通过这样的注重过程与培养学生们的动手能力的教学,让学生们可以极大地加强自己的专业技术能力。通过这种方式,各个职业学校也可以圆满的完成自己为国家培育优秀职业技能人才的重要任务。     

Modeling and control of Wiener-type processes

We develop a simple relay feedback method to identify Wiener-type nonlinear processes. It separates the identification problem of the nonlinear static function from that of the linear dynamic subsystem to simplify the identification procedure significantly. Owing to the separation, the unmeasurable output of the linear dynamic subsystem can be obtained in a straightforward manner. Then, determining the model structure of the nonlinear static function becomes very simple and the estimates are robust to additive output noises. We can identify the whole activated region of the nonlinear static function as well as the ultimate information of the linear dynamic subsystem from only one relay feedback test. More information on the linear dynamic subsystem can be estimated by well-established linear system identification methods from additional tests. We use a nonlinear control strategy to compensate the nonlinear dynamics of the Wiener process so that the design parameters can be determined by usual tuning rules developed for linear processes and a high control performance can be achievable as in linear processes.     

The Chemistry of Water Treatment Processes Involving Ozone,Hydrogen Peroxide and Ultraviolet Radiation

Advanced oxidation processes are defined as those which involve the generation of hydroxyl radicals in sufficient quantity to affect water purification. The theoretical and (practical yield of OH from O₃ at high pH, 0₃/H₂0₂, O₃/UV and H₂O₂/UV systems is reviewed. New data is presented which illustrates the importance of direct photolysis in the O₃/UV process, the effect of the H₂0₂:0₃ ratio in the O₃/H₂O₂ process, and the impact of the low extinction coefficient of H₂O₂ in the H₂0₂/UV process.     

The voidage function and effective drag force for fluidized beds

Here, an experimental investigation on the effective drag force in a conventional fluidized bed is presented. Two beds of different particle size distribution belonging to group B and group B/D powders were fluidized in air in a diameter column. The drag force on a particle has been calculated based on the measurement of particle velocity and concentration during pulse gas tests, using twin-plane electrical capacitance tomography. The validity of the voidage function “correction function”, (1−ε_s)ⁿ, for the reliable estimation of the effective drag force has been investigated. The parameter n shows substantial dependence on the relative particle Reynolds number , and the spatial variation of the effective static and hydrodynamic forces. It is also illustrated that, a simple correlation for the effective drag coefficient as function of the particle Reynolds number (Re_p), expressed implicitly in terms of the interstitial gas velocity, can serve in estimating the effective drag force in a real fluidization process. Analysis shows that, the calculated drag force is comparable to the particle weight, which enables a better understanding of the particle dynamics, and the degree of spatial segregation in a multi-sized particle bed mixture. The analogy presented in this paper could be extended to obtain a generalized correlation for the effective drag coefficient in a fluidized bed in terms of Re_p and the particle physical properties.     

PROCESS CONTROL PERSPECTIVE FOR PROCESS ANALYTICAL TECHNOLOGY: INTEGRATION OF CHEMICAL ENGINEERING PRACTICE INTO SEMICONDUCTOR AND PHARMACEUTICAL INDUSTRIES

FDA's Process Analytical Technology (PAT) initiative provides an unprecedented opportunity for chemical engineers to play significant roles in the pharmaceutical industry. In this article, the authors provide their perspectives on (1) the need for chemical engineering principles in pharmaceutical development for a thorough process understanding; (2) applications of chemical engineering principles to meet the challenges from the semiconductor and pharmaceutical industries; and (3) the integration of chemical engineering practice into the semiconductor and pharmaceutical industries to achieve process understanding and the desired state of quality-by-design. A real-world case study from the semiconductor industry is presented to demonstrate how a classic chemical engineering concept, mixing homogeneity, can be implemented by inducing forced flow to ensure an excellent copper electrochemical plating process performance and to improve product quality substantially. Further, a case study of brake system design is discussed with the concept of Dr. Taguchi's robust engineering design to illustrate how quality-by-design can be achieved through appropriate experimental design, in conjunction with the discussion on the concept of quality-by-design in pharmaceuticals. Third, a case study of freeze-dried sodium ethacrynate is presented to demonstrate the vital importance of controlling the processing factors to achieve the desired product stability. Finally, the problems of the current pharmaceutical manufacturing mode, the opportunities and engineering challenges during implementation of PAT in the pharmaceutical industry, and the role of chemical engineering in implementation of PAT is discussed in detail.