A review of “ MODERN COATING AND DRYING TECHNOLOGY” Edward Cohen and Edgar Gutoff VCH Publishers,Inc New York NY 1992, 310 p

ABSTRACT

Recently some workers in the field of electrostatics have proposed a “new” method of electroosmotic dewatering (EOD) in which a third electrode (called the “gate” electrode) is placed between the anode and the cathode to enhance the EOD. These authors present a conceptual analysis in terms of the notions of a field-effect transistor (FET). We show here that the proposed method is simply a variation of the multistage EOD already practiced by the workers in this field. It is further demonstrated that an analysis based on the FET model is not applicable to the phenomena involved in the proposed EOD method.     

ELECTROOSMOTIC DEWATERING (EOD) OF CLAYS AND SUSPENSIONS: COMPONENTS OF VOLTAGE IN AN ELECTROOSMOTIC CELL

ABSTRACT

In the electroosmotic dewatering (EOD) of clays, suspensions and fines, a continuous or interrupted DC voltage, V, is applied between the anode and the cathode. In the previous literature on this subject the components of V have not been completely clarified.

Following a brief outline of the EOD that emphasizes the central role of the electrochemical double layer, we provide an analysis of the components of V, Three case are distinguished

(1)Threshold voltage V-n, for initiating the EOD and its connection to the so-called open-circuit voltage;

(2)EOD at very low voltages viz. around IV;

(3)EOD at very high rates for prolonged times where electrodes such as A𝓁 can form barrier oxides and some “caking” is also observed near the a node, This attempt to define the components of V under different conditions of EOD is aimed to identify parameters and processes that arc involved in the effect of V on EOD; RT for example, it is generally not recognized that —pH can form a significant part of V F under some conditions of EOD     

SOME OBSERVATIONS ON ELECTROOSMOTIC DEWATERING (EOD) UNDER A.C. ELECTRIC FIELD CONDITIONS

ABSTRACT

The electroosmotic dewatering (EOD) reported by Yoshida et al. (3) under low-frequency A.C. conditions is shown to be equivalent to EOD carried out under D.C. conditions with periodic polarity reversal. The interpretation of their results is carried out here in terms of electrochemical considerations (e.g., pH gradients, zeta potentials) with lesser role assigned to factors considered paramount by Yoshida, e.g., heating effect in the dry region near the anode.

More importantly, it is pointed out that the practical advantages of EOD under A.C. conditions claimed by Yoshida et al. are based on an invalid comparison of their results with EOD under continuous D.C. conditions; a comparison under equivalent conditions would be between low-frequency A.C. conditions and those under D.C. field but with periodic polarity reversal — the enhanced dewatering claimed under “A.C. conditions” by Yoshida would disappear when EOD under D.C. conditions with periodic interruption and/or polarity reversal is considered.     

THE RELATION OF DEFECTS IN ENAMEL COATINGS TO HYDROGEN IN STEEL*

The effects of hydrogen as functions of time, temperature, and impurities in steel are described and experimentally demonstrated. Experimental evidence is presented to show that the blistering and boiling action over carbide areas in steel are due principally to hydrogen that associates with the carbon. Steel enameling stock contains quantities of hydrogen which may effuse during firing to cause or aggravate such phenomena as “boiling,”“primary boiling,”“rebelling,”“blistering,” and “bubbling.” Low-temperature effusion of hydrogen contributes to other defects, including “fishscaling,”“delayed fishscaling,” and possibly “pop-offs,”“jumping,”“shiners,” and some cases of “chipping” and, perhaps, “bursting” of enamel on cooking utensils. These defects have seldom been identified with hydrogen evolution. An indirect effect of hydrogen on “copperheads” and “black specks” is also identified. An exhaustive review of both English and German literature on enameling defects is included. Many observations recorded in the literature are shown to agree with the hydrogen theory. Certain types of inclusions in steel are shown to react with occluded hydrogen to form compounds that will not dissociate appreciably at some enamel-firing temperatures, and critical quantities of the hydrogen are therefore prevented from reaching the enamel coating during firing to cause blistering and related defects.     

基于故障树方法的机动车燃油大气环境风险评价：以杭州市为例

由于城市化、工业化和机动车数量的快速增长,灰霾天气已成为中国许多大城市亟待解决的严重环境污染问题。大量石油燃料消耗产生的机动车尾气排放可能是引起城市灰霾污染的一个关键因素。以长江三角洲的代表性城市杭州市为具体案例,探索将安全工程领域的故障树方法应用在机动车燃油尾气排放大气环境风险评价和与灰霾天气的致因机理分析上。通过辨识导致城市机动车尾气过量排放的关键风险因子,构建了杭州市“灰霾天气–机动车尾气过量排放”的故障树。另外采用结构、概率以及临界重要度分析,对关键风险因子对顶上事件“灰霾天气–机动车尾气过量排放”的贡献和影响程度进行了定性和定量分析。分析结果表明,过量机动车使用,严重的交通堵塞、高污染机动车的不当使用以及监管不严是对杭州市机动车尾气过量排放影响较大的关键风险因子。可为城市机动车燃油环境风险因子评价以及管理提供一种简洁有效的方法和思路。     

Expertensysteme – ein Hilfsmittel der Prozeß-Synthese

Expert systems for process syntheses . Commercial programs used in computer-aided development of chemical processes need a process flowsheet as starting point. Preparation of flowsheets is based largely on human experience, an uncertain kind of knowledge expressed by heuristic rules. These rules are recognized as true and advantageous in most cases without having the validity of a law. Logic programming languages derived from research on artificial intelligence are proven tools for handling heuristics with so-called “expert systems”. The flowsheets proposed by the expert system reduce all theoretically possible results to a few structures. The example of structuring distillation sequences illustrates what can be expected using an “expert system” in the area of “problem solving” by comparing its proposed sequences with optimized problems.     

Hybrid knowledge-based tool for mixing equipment selection – the fuzzy neural network

The hybrid knowledge-based system proposed in this paper consists of a “stiff” segment, viz. the expert system based on the object-oriented approach, and a flexible part, viz. the neural network. Some of the input parameters of the problem and output parameters of the “stiff” system are presented as the fuzzy numbers. Detailed information is also presented about the development of the neural network. The most evident advantages of the proposed introduction of a hybrid architecture of the knowledge-based system are a faster evaluation and generation of design alternatives and support of systematic searches and storage of experience. In addition, the resulting ability to extrapolate results would be unattainable with separately acting stiff and flexible systems. A system for the estimation of the parameters of a mixing system for wastewater treatment is presented as an example to illustrate the principles of the hybrid system.     

The new database Seed Oil Fatty Acids (SOFA)

After more than three years the internet‐based database “Seed Oil Fatty Acids” (SOFA) is available again (http://sofa.mri.bund.de) free of charge after registration. This database is a unique collection of information about the fatty acid composition of wild plant seeds. The data were collected from the appropriate pharmaceutical, botanical and chemical literature over a period of more than 40 years. With financial assistance from the German Federal Ministry of Food, Agriculture and Consumer Protection via the lead partner Agency for Renewable Resources (FNR) the new database system based on mySQL and PHP as source language was created. Currently more than 18.000 different tables with about 130.000 individual data sets are searchable from the database. Additionally the database contains about 600 different fatty acids with more than 2.500 synonyms. The search for a defined (e. g. unusual or technically interesting) fatty acid or plant (family, genus, species) which contains this fatty acid is possible online. This search can be done by use of synonyms for the fatty acid (trivial name, systematic name) but also by using substructures of the fatty acid defined by an alpha‐numeric delta‐notation. It is possible to combine the search for different fatty acids by Boolean operators such as “AND” and “OR”. This paper gives an overview about the application of the different search forms and provides search examples.     

Umweltschutz,eine Aufgabe der Verfahrenstechnik

Environmental protection, a task of chemical engineering . The environmental burden in air and water in Germany is surveyed. The terms “eco-unobjectionable technology” and “disposal technology” are then considered with the aid of examples. These are fundamental chemical engineering approaches for reducing or eliminating environmental burdens due to industrial production processes. “Ecounobjectionable processes” are those in which undesired pollutants are not even formed, i. e. when possible emissions are eliminated at source. If this is only partly possible, or impossible, then disposal measures are adopted. This means removal of unavoidable pollutants from waste gases and waste water, and the disposal of other wastes.     

Der Einfluß von Sorte und Standort sowie einzelner definierter Klimafaktoren auf den Tokopherolgehalt im Rapsöl

Influence of Variety, Location and Individually Defined Climatic Factors on the Tocopherol Content of Rapeseed Oil The total tocopherol content was determined in the material from different breeding lines, from field experiments (7 varieties from 3 German and 3 foreign locations) as well as from a phytotrone experiment in which the climatic conditions, such as temperature and day length, were varied. Genetic variations were detected predominantly in the breeding material which showed distinct differences between the breeding lines “low-erucic”, “low-glucosinolate” and “high-linoleic”. In the material obtained from field experiments, distinct differences were observed due to location, however, very little difference between the varieties was detected. Studies on the effect of climatic factors, such as temperature and day length, carried out in phytotrone experiments revealed that both of these factors affect the tocopherol content; higher temperatures and shorter periods of light (short day) increase the tocopherol content.     

An overview of solvents in resin–dentin bonding

Resin bonding to dentin is less durable than bonding to enamel. Bonding to dentin had been a great challenge till date. Though the current dental adhesive systems have tremendously improved the complex dentin bonding, there are still challenges that need to be addressed. Improper handling of the dental adhesive systems is one of the several reasons for the decrease in durability of resin–dentin bonds over time. Improper handling includes inappropriate storage and inaccurate method(s) of application. Solvents incorporated in the dental adhesive systems are known to dissolve methacrylate monomer/co-monomer blends and the initiator/co-initiator systems. These solvents are volatile and they play several important roles in achieving successful and durable bond to dentin. Lack of knowledge about the role of solvents used in dental adhesives could be one of the reasons for improper handling of the dental adhesive systems. This overview discusses the solvent aspects of current dental adhesive systems and their applications in bonding. The overview consists of published literature retrieved from “Pubmed”, by using specific key words “solvents”, “resin adhesives”, “dentin”, “bonding”. The relevant literature was retrieved after screening the titles and the abstracts. Further relevant articles that were included for the overview were retrieved from the reference lists of the initially retrieved articles. The literature seems to indicate that solvent type, solvent content and other factors, like storage of the adhesives and methods of application play a major role in dentin bonding. The knowledge acquired on the solvents and their roles in dentin bonding would enable the users of the dental adhesives to handle them appropriately and consequently achieve strong and durable resin–dentin bonds.     

ELECTROOSMOTIC DEWATERING (EOD) OF CLAYS AND SUSPENSIONS: COMPONENTS OF VOLTAGE IN AN ELECTROOSMOTIC CELL

In the electroosmotic dewatering (EOD) of clays, suspensions and fines, a continuous or interrupted DC voltage, V, is applied between the anode and the cathode. In the previous literature on this subject the components of V have not been completely clarified.

Following a brief outline of the EOD that emphasizes the central role of the electrochemical double layer, we provide an analysis of the components of V, Three case are distinguished

(1)Threshold voltage V-n, for initiating the EOD and its connection to the so-called open-circuit voltage;

(2)EOD at very low voltages viz. around IV;

(3)EOD at very high rates for prolonged times where electrodes such as Al can form barrier oxides and some “caking” is also observed near the a node, This attempt to define the components of V under different conditions of EOD is aimed to identify parameters and processes that arc involved in the effect of V on EOD; RT for example, it is generally not recognized that —pH can form a significant part of V F under some conditions of EOD     

CuCN and Trimethylsilyl Chloride-Catalyzed Regiospecific Grignard Reactions to CF3-Containing Allylic Derivatives

CF₃-containing allylic alcohol derivatives were treated with an appropriate Grignard reagent in the presence of catalytic amounts of CuCN and trimethylsilyl chloride (TMSCl) to furnish products via the clean anti-S_N2′ mechanism. Experimental results as well as ab initio computational analyses unambiguously demonstrated the important roles of TMSCl as a Lewis basic additive for smooth promotion of reductive elimination and inhibition of the “Cu···F” elimination leading to undesired byproduct formation.     

Catalytic oxidation of carbon monoxide under periodic operation

A growing literature demonstrates resonance of the rate of CO oxidation with frequency of composition switching and that a global increase in rate under composition modulation is possible. Differences are found for the various metal catalysts used: CO oxidation is stimulated at frequencies between 0.1 and 1.0 Hz over noble metals, whereas stimulation occurs at frequencies below 0.05 Hz with oxide catalysts. Multiple resonances with an apparent harmonic relationship, “wrong-way” response, or very slow relaxation to reproducible cycles have been observed. These differences suggest mechanisms through which rate improvements arise are not the same for all catalysts.     

Classification of properties of elastomers using the “optimum property concept.” I. Introduction

An attempt is made to distinguish properties of elastomers by types. “Basic properties of materials” or “network properties” in elastomers are properties which either increase or decrease from the liquid to the solid state of materials or over the range of the “elastomeric plateau” of elastomers. From these are distinguished properties that exhibit characteristic maxima and are therefore “maximum properties” or bivalued properties. Mechanical failure properties show the characteristics of “maximum properties.” The maxima in “maximum properties” generally do not coincide. This noncoincidence of the maxima with a change in a “basic property of a material” has major theoretical and practical implications, for example, it is the cause of the crossovers in the relative performance rating of materials under different test conditions. The implications of this noncoincidence of the failure property maxima on the relevance of correlations between these properties are discussed. A change in the testing conditions is reflected in a shift of the optimum value in a “basic property of a material” with respect to a specific “maximum property.” Data and certain conclusions in the literature are interpreted on the basis of this concept. Examples of the limitations of the validity of mathematical relationships are presented. Also, a definition of the term “state of cure” is proposed and a suggestion for the rating of severities of test equipment and applications of elastomeric materials recommended. The effect of increased degrees of crosslinking for a series of polymers and crosslinking agents is assessed. It is suggested that the “mechanisms” of failure properties will remain elusive if their rationalization is attempted on the basis of other failure properties, e.g., the mechanism of abrasion on that of tear strength or cut growth. The main purpose of this proposal is to provide support for a drastic reduction in laboratory testing by identifying those properties which can lead to different relative ratings in routine evaluations and actual applications. A more empirical approach to materials evaluations is recommended based on the calibration of laboratory instrumentation with respect to specific applications. A de-emphasis of routine evaluations of materials on the basis of their “maximum properties” seems to be justified.     

Structural Chemistry,Fuzzy Logic,and the Law

Chemistry is generally considered to be one of the exact sciences, which implies that much of the thinking and reasoning can be governed by “always” and “never” laws and rules. However, in practice, much of chemistry involves concepts that invoke general rules with the exceptions to those rules arousing curiosity and generating new experiments and theories that facilitate the progress of chemical science. The lack of precision, in fact, requires a mode of thinking and operating that has been called “fuzzy logic”, not necessarily in a pejorative sense, but rather recognizing the fundamental nature of this experimental science and how it plays out in practice. We provide herein some examples of fuzzy logic in the practice of chemistry and demonstrate how these are manifested in the role and behavior of expert witnesses, particularly in pharmaceutical patent litigations that deal with the solid forms of active pharmaceutical ingredients.     

Combined mass and heat exchange network synthesis based on stage-wise superstructure model☆

Integrating multiple systems into one has become an important trend in Process Systems Engineering research field since there is strong demand from the modern industries. In this study, a stage-wise superstructure-based method is proposed to synthesize a combined mass and heat exchange network (CM&HEN) which has two parts as the mass exchange network (MEN) and heat exchange network (HEN) involved. To express the pos-sible heat exchange requirements resulted from mass exchange operations, a so cal ed“indistinct HEN super-structure (IHS)”, which can contain the all potential matches between streams, is constructed at first. Then, a non-linear programming (NLP) mathematical model is established for the simultaneous synthesis and optimiza-tion of networks. Therein, the interaction between mass exchange and heat exchange is modeling formulated. The NLP model has later been examined using an example from literature, and the effectiveness of the proposed method has been demonstrated with the results.     

Modelling of A Fluidized Bed Drier Using Artificial Neural Network

ABSTRACT

Proper modelling of a fluidized bed drier (FBD) is important to design model based control strategies. A FBD is a non-linear multivariable system with non-minimum phase characteristics. Due to the complexities in FBD conventional modelling techniques are cumbersome. Artificial neural network (ANN) with its inherent ability to “learn” and “absorb” non-linearities, presents itself as a convenient tool for modelling such systems.

In this work, an ANN model for continuous drying FBD is presented. A three layer fully connected feedfordward network with three inputs and two outputs is used. Backpropagation learning algorithm is employed to train the network. The training data is obtained from computer simulation of a FBD model from published literature. The trained network is evaluated using randomly generated data as input and observed to predict the behaviour of FBD adequately.     

Shape memory gels made by the modulated gel technology

Shape memory gels based on interpenetrating only part of one gel network with another gel network have been synthesized. These gels consist of two parts: a control element, which is responsive to a designated environmental stimulus, and a nonresponsive substrate element. By designing the pattern in the gelation process, a variety of shapes are obtained including “spiral,” “square,” “fish,” “numbers,” “alphabets,” and “tube.” The change between two different shapes can be controlled by external stimuli such as temperature and is reversible. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1173–1178, 1997