Prosyn—an MINLP process synthesizer

This paper reports the development of the program PROSYN, an automated implementation of the modelling/decomposition (M/D) strategy by Kocis and Grossmann (Computers chem. Engng 13, 797–819, 1989) for the MINLP optimization of process flowsheets. A systematic procedure is first presented for the decomposition of general superstructures of process flowsheets that avoids the optimization of units with zero flow. A model for simultaneous optimization and heat integration is also proposed that can account for area and energy considerations. Finally, a computer implementation is described that is suitable for the complex logic involved in the M/D strategy for the synthesis and heat integration of process flowsheets. Examples are presented to illustrate each of these points, as well as the performance of PROSYN.     

Cavity temperature—an important parameter in the injection molding process

The paper stresses the importance of cavity temperature in the injection molding process of thermoplastics. From the study of the temperature field in the mold, it follows that there is no such thing as a uniform mold temperature. The heat balance equation for the injection mold is discussed in detail. It shows that the sum of the heat exchanges during the cycle equals zero. There is an extensive explanation of the heat transfer from the melt to the mold, the heat exchange with the environment, and between the heat exchange medium and the mold. New criteria are given for the cavity material selections. The cavity temperature is a complex function of static and dynamic parameters and should be kept constant in the equal parts of the cycle. This demands a new way of regulating the temperature.     

Recent resist developments in Japan—a review

Several kinds of resist materials for microlithography have been developed in Japan. Poly(4-vinyl phenol) sensitized with 3,3′-diazidodiphenyl sulfone has been proved to be a high resolution negative deep UV resist with high sensitivity and good resistance to dry etching. The use of this resist enables a 1:1 projection printer to replicate fine patterns with 1 micrometer (μm) minimum feature size at the rate of 90 wafers per hour. Poly(methyl isopropenyl ketone) (PMIPK) has been investigated as a positive deep UV resist. Several resists composed of PMIPK with or without sensitizers are commercially available. Dry-developable photo- and deep UV resists comprising PMIPK and aromatic bisazides have been developed. Poly(glycidyl methacrylate) having the sensitivity of 0.4 micro Coulomb (μC)/per square centimeter (cm²) is now being routinely used as a negative electron beam resist in the fabrication of chromium masks. Recently, aromatic polymers such as chloromethylated polystyrene, iodinated polystyrene, chloromethylated poly(α-methylstyrene), poly(vinylnaphthalene) and its copolymers have been investigated as dry-etching resistant electron beam resists.     

Burning characteristics of beds and bedding—situation and developments

The term ‘bed’ has a variety of meanings in different countries. In central Europe, ‘bed’ is used for a bedstead with a mattress, a duvet and a pillow, Following clear definitions of the components of a ‘bed’ the author considers methods for testing the burning characteristics of beds and reports on experiences with model beds in fire tests.     

Electrochemical photovoltaic cells—review of recent developments

Photoelectrochemistry is attracting extensive attention from scientists worldwide for its use in converting light energy into electricity in electrochemical photovoltaic cells, the most common form of which, dye sensitized solar cells (DSSCs), can offer both flexibility and transparency. Their efficiencies are now comparable with amorphous silicon solar cells but at a much lower cost. This review covers not only the fundamentals of electrochemical photovoltaic cell operation but also recent advances in research and development for industrial applications. The most recent research topics relating to DSSCs, for example, applications of nanostructured n‐type semiconducting electrodes, ionic liquid electrolytes and graphene and carbon nanotube electrodes are all included. In addition, the storage of electrochemical energy by electrochemical photovoltaic cells has also been reviewed. Copyright © 2010 Society of Chemical Industry     

Development of an instrumented and automated flash sintering setup for enhanced process monitoring and parameter control

Heterogeneous grain size distributions due to cathodic reduction of samples sintered by flash sintering (FS) are a recurring problem. Herein, we present an experimental setup for FS with refined control of the process parameters, especially the electric current density, to control the power peak that could reduce the grain size heterogeneity of sintered materials. The real-time control of the equipment enabled the development of a Multi-Step Flash Sintering (MSFS) process. This technique involves varying the maximum current density at the onset of the abrupt shrinkage of the sample during the flash phenomenon, smoothing the shrinkage and power density curves, avoiding power peak and allowing its control in real time. Tetragonal stabilised zirconia (3YSZ) was sintered in this equipment by both FS and MSFS. Preliminary results of this study were promising in terms of density control and improvement of grain size homogeneity.     

Advances and selected recent developments in state and parameter estimation

This paper deals with two topics from state and parameter estimation. The first contribution of this work provides an overview of techniques used for determining which parameters of a model should be estimated. This is a question that commonly arises when fundamental models are used as these models often contain more parameters than can be reliably estimated from data. The decision of which parameters to estimate is independent of the observer/estimator design, however, it is directly affected by the structure of the model as well as the available data. The second contribution is an overview of recent developments regarding the design of nonlinear Luenberger observers, with special emphasis on exact error linearization techniques, but also discussing more general issues, including observer discretization, sampled data observers and the use of delayed measurements.     

Polymer melt elongation—methods,results, and recent developments

For film blowing of polyethylene it has been shown previously that melt elongation is very powerful for polymer characterization. With two types of rheometers, simple (also called “uniaxial”) elongational tests as well as creep tests can be performed homogeneously. In simple elongation, the melts of branched polyethylene show a remarkable strain hardening. With respect to their advantages and disadvantages, these rheometers complement each other. For multiaxial elongations the various modes of deformation can be performed by means of the rotary clamp technique. With the strain rate components ordered such that \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}₁₁ ? \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}₂₂ ≥ \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}₃₃, the ratio m = \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}₂₂/\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \varepsilon $\end{document}₁₁ characterizes the test mode. The Stephenson definition of the elongational viscosities makes use of the linear viscoelastic material equation and proves to be very efficient because the linear shear viscosity (t) (“stressing” viscosity) can act as the reference for the nonlinear behavior in elongation. Results are given for polyisobutylene measured not only in simple, equibiaxial, and planar elongations, but also in new test modes with a change of m during the deformation. This allows one to investigate the consequences of a deformation-induced anisotropy of the rheological behavior.     

Translation of variables and implementation of efficient logic‐based techniques in the MINLP process synthesizer MIPSYN

This article describes alternative GDP formulation and convex hull representations for process synthesis problems and their implementation in a unique MINLP process synthesizer MIPSYN. A special translation of variables in mixed‐integer, relaxed, and logic‐based variations has been proposed, which enables modeling and solving process alternatives in a narrowed lifted space of variables, defined by nonzero lower and upper bounds. Based on these translation variations, alternative formulations have been developed for convex hulls, multiple‐term generalized disjunctive programming problems, and logic‐based outer‐approximation algorithm, all of them being specialized for the synthesis of process flowsheets. Several studies were performed and three different large‐scale synthesis problems were solved to test the performance and efficiency of different formulations. This initial research indicates that the proposed alternative convex hull representation usually outperforms the conventional one when solving both MILP and NLP steps in highly combinatorial MINLP process networks problems. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

New developments in phospholipase A<Subscript>2</Subscript>

Some of the most recent data concerning various phospholipases A₂, with special emphasis on secretory, cytosolic, and calcium-independent phospholipases A₂ are summarized. Besides their contribution to the production of proinflammatory lipid mediators, the involvement of these enzymes in key cell responses such as apoptosis or tumor cell metastatic potential is also discussed, taking advantage of transgenic models based on gene invalidation by homologous recombination. The possible role of secretory and cytosolic platelet-activating factor acetyl hydrolases is also briefly mentioned. Finally, the ectopic expression in epididymis of an intestinal phospholipase B opens some novel issues as to the possible function of phospholipases in reproduction.     

分子筛上甲醇转化过程的热力学和拓扑结构

现代新型煤化工是我国当今基础有机化学工业发展的新亮点,也是世界化工界的又一次革命。煤制化学品路线经历气化、变换、甲醇合成、甲醇制烃类等过程,其中,最为重要的是分子筛上甲醇转化的过程。本文综述了分子筛上甲醇转化的相关研究,一方面从ZSM-5上甲醇转化的生成烃池及烯烃的热力学机制和产物分布出发,介绍了多甲基苯生成烯烃热力学平衡模型和其中的芳烃池生成烯烃热力学机制,另一方面,介绍了基于Ising模型的分子筛离散拓扑结构模型。利用分子筛孔道堵塞与围棋中“气”的有无的类似性,能够很好地再现SAPO-34上的相变失活现象和不均匀的积炭分布现象。以模型为指导,介绍了一些分子筛多级结构构筑的工作,这些工作很好地提升了催化剂选择性和寿命。这些概念对于准确理解甲醇在分子筛上的反应与失活机制、产品分布及提高选择性有指导意义。     

Improving prediction capabilities of complex dynamic models via parameter selection and estimation

Many mathematical models describing complex (bio-)chemical reaction networks with a high level of detail are available in the literature. While such detailed models are desirable for investigating the dynamics of a particular component, it is often questionable if it is possible to verify these models due to the limited amount of quantitative data that can be generated. Even if it is not possible to estimate all parameters of these models then one would still be interested in determining which parameters should be estimated.This paper addresses this point and introduces a technique for determining the parameters of a model that should be estimated from experimental data. The focus of this work is on ensuring that the model has good prediction capability as over-fitting the model to noisy experimental data is avoided. Towards this goal, a forward selection approach for selecting a subset of parameters for estimation while taking uncertainty into account is developed to minimize the mean squared prediction error of the model. It is shown that the developed technique is closely related to the often-used orthogonalization method. The technique is applied to a model of the NF-κB signal transduction pathway. The presented method is able to generate a smaller mean squared error than estimation of all parameters and also outperforms the orthogonalization method.     

New process for producing an extrusion laminated film without any chemical primer—non anchor coating extrusion laminating process

A new process, the Non Anchor Coating Extrusion Laminating Process for producing an extrusion laminated film without any chemical primer, was investigated. Good adhesive properties were obtained by combining an ozone treatment of a molten polyethylene (LDPE) web and an activation treatment of the polyamide (ONy) substrate film. The adhesion mechanism induced by the new process was studied by FT-IR, ESCA and extraction of unreacted polyamide from the laminated samples. The peel strength between the ONy and LDPE laminated films produced with this process was greater than that for laminated film made with a conventional lamination process using anchor coating agents. A model of the adhesive mechanism is proposed. Hydrogen and covalent bonds through oxygenated functional groups are responsible for the enhanced adhesion.     

Precise parameter estimation in reaction modelling — sensitivity in choosing experimental conditions

A sequential experimental design developed by Box and coworkers was reviewed and the sensitivity of experimental conditions in increasing the preciseness of parameter estimates was examined. Continuous kinetic data were utilized for the examination. It is found that experimental conditions are in some cases rather sinsitive and slightly deviated experimental conditions from those specified by the criterion may induce some difficulty in reducing the size of confidence region of parameter estimates.     

关于橡胶补强的新进展

分别阐述了溶胶-凝胶工艺原位生成的填料和碳纳米管等材料对强性体的补强作用,并与粘土填料的补强效果进行了对比。