Technology for processing natural energy resources based on the concept of optimal chemical engineering system organization

The problem of coordinating the target processes within a virtual system followed by the addition of corresponding heat exchanger and utility elements to the above processes has been considered. The problem has been solved using a sequential synthesis algorithm that involves selecting the target processes of the system, their optimal coordination within the system that combines the target processes, the selection of the heat exchanger elements and optimal load distribution, and the selection of optimal system topology. The functioning of the algorithm has been demonstrated based on an example of a unified system comprised of lignite gasification and the water-gas shift reaction of the synthesis gas in order to achieve the key component ratio H₂: CO = 2: 1 for the production of methanol and higher alcohols. A specific feature of the algorithm proposed for the example under consideration is that it does not have feedback, since optimal solutions are chosen at every step of the process of increasing the system complexity element-by-element according to the corresponding organization criteria, which take this process into account.     

New approaches to the integrated synthesis of flexible automated chemical engineering systems

The problems of optimizing the design and operational (control) variables during the integrated design of flexible automated complexes of chemical engineering process (CEP)—automated control systems (ACS) under conditions of the uncertainty of physicochemical, engineering, and economic initial data have been formalized. The selection of the best available version of a flexible automated complex is performed by means of the pairwise comparison of alternative versions of automated complexes using criteria that take into account both the quality of the manufactured products and the characteristics of energy and resource saving, on one hand, and the quality of transient processes in the ACS, on the other hand. A two-stage problem of stoichastic optimization of flexible automated complexes with hard and soft constraints has been stated, and a new approach to its solution has been proposed. An example of the integrated design of a flexible continuous process of azo pigments synthesis and a system of the optimum stabilization of its conditions in the presence of an interval uncertainty of the kinetic coefficients of the chemical reaction and individual engineering variables has been shown.     

化学实验教学资源开发的重要性分析

近年来,随着社会的不断发展以及教育事业的不断变革,化学实验在化学教育中所占的比重越来越大。业界人士不再仅仅关注对学生理论知识的教育,他们更大程度上关注在教学中的实践问题,及在化学教学中引入了大量的化学实验,采取实验教学的方法,激发学生学习化学的兴趣、学习的主动性、创新能力和实践能力等。为寻求完善化学实验教学方法,促进化学教学质量不断提高。国家越来越重视化学实验教学资源的开发与利用,旨在让教师和学生对化学实验更加重视,促进化学教育的有效进行,提高课堂效率。     

UV-visible technique for studying powder coatings and their dissolution

UV-Visible (UVV) technique used to monitor powder coating and its dissolution processes from hard latex particles. Three sets of latex coatings were prepared from poly(methyl methacrylate) (PMMA) particles. The first set of coatings was annealed at elevated temperatures in various time intervals during which reflected photon intensity, I_rf, was measured. The second set of coatings was annealed at various temperatures in 10 min time intervals during which transmitted intensity, I_tr, was measured. I_rf first decreased and then increased as the annealing temperature was increased. Decrease in I_rf was explained with the void closure mechanism due to viscous flow. Increase in I_tr and I_rf against time and temperature were attributed to an increase in crossing density at the junction surface. The activation energy of viscous flow, ΔH, was measured and found to be around 8 kcal/mol and the back and forth activation energies (ΔE_rf and ΔE_tr) were measured and found to be around 49 and 53 kcal/mol for a reptating polymer chain across the junction surface. Diffusion of solvent molecules (chloroform) into the annealed latex coatings was followed by desorption of PMMA chains for the third set of films. Desorption of pyrene, P, labeled PMMA chains was monitored in real-time by the absorbance change of pyrene in the polymer-solvent mixture. A diffusion model with a moving boundary was employed to quantify real-time UVV data. Diffusion coefficients of desorbed PMMA chains were measured and found to be between 2 and 0.6 × 10⁻¹¹ cm² s⁻¹ in the 100 and 275°C temperature range. Presented at the 2000 Spring Meeting of the PMSE Div. of the American Chemical Society, March 26–30, 2000, San Francisco, CA. Dept. of Physics, Maslak 80626 Istanbul, Turkey. Dept. of Physics, 22030 Edirne, Turkey.     

Method and equipment for studying acoustic emission in failure of chemical fibres

St. Petersburg Institute of Textile and Light Industry. Translated from Khimicheskie Volokna, No. 6, pp. 60–61, November–December, 1992.     

Dielectric behavior of the constituents of the natural resin shellac

The dielectric relaxation data of the constituents of natural resin shellac have been analyzed by the Cole–Cole method at temperatures between 10° and 90°C in the frequency range of 50 Hz to 500 kHz. The functional groups present in hard and soft lac appeared to be responsible for the dielectric properties exhibited by shellac below and above its glass transition and melting temperature, respectively. A combination of 70% hard lac and 30% soft lac was found to exhibit the dielectric properties of shellac satisfactorily.     

桑黄化学成分及药理作用的研究进展

桑黄是一种大型野生真菌,作为传统中药已有两千多年的历史记载,因其富含的多种化学成分在抗氧化、降血糖、抗肿瘤、抑菌等方面均表现出药理作用,被称为森林黄金.本文对桑黄的多种化学成分和药理作用进行阐述及总结,为桑黄在今后的食品药品产业的开发与利用方面提供科学的依据与重要的理论参考.     

Future manufacturing approaches in the chemical and pharmaceutical industry

In order to develop future manufacturing strategies the chemical and pharmaceutical industry works on the implementation of process intensification and new modularization methods. In this paper current challenges, process intensification approaches and future manufacturing initiatives are summarized and discussed.     

几种天然防晒成分的提取及稳定性研究

分别从槐米、黄芩、芦荟中提取天然防晒成分芸香甙（芦丁）、黄芩甙、芦荟甙，考察它们的紫外吸收特性，并对提取条件及稳定性进行了研究。     

Use of secondary resources for increasing the chemical stability of glass enamels

The chemical stability of glass enamels obtained with available synthetic and close to synthetic raw materials is investigated. The charge and chemical compositions of two enamels based on available raw materials are presented. The developed enamels are recommended for the chemical and metallurgical industries as acid-resistant coatings.Translated from Steklo i Keramika, No. 10, pp. 30 – 32, October, 1995.     

Online monitoring techniques for studying evolution of physical,rheological and chemical effects along the extruder

Abstract

During extrusion and/or compounding, polymeric systems may be subjected to a complex thermo-mechanical-chemical environment, therefore monitoring the evolution of physical, rheological and chemical effects along the extruder is an important tool assisting process understanding and optimisation. Online monitoring concepts that allow sample collection, rheology measurements and RTD characterisation at specific locations along the screw axis of an extruder are presented. Each practical set-up is presented, its operation is described and the results obtained are validated experimentally. Finally, examples of the use of the tools developed for the study of specific polymer systems are presented and discussed.     

Astonishing diversity of natural surfactants: 4. Fatty acid amide glycosides,their analogs and derivatives

FA amide glycosides are of great interest, especially for the medicinal and pharmaceutical industries. These biologically active natural surfactants are good prospects for future chemical preparation of compounds useful as antibiotics, anticancer agents, or for industry. More than 200 unusual and interesting natural surfactants, including their chemical structures and biological activities, are described in this review article. For previous article in this series see Reference 1.     

Dialog intelligent systems for natural and chemical fibre spinning technology

An important direction in the use of computers for technological purposes is the creation of intelligent technological systems that simulate the intellectual activity of the researcher and make it accessible to the practitioner. The use of a morphological approach to synthesis of intelligent process systems of different structure was suggested. The characteristics of automated intelligent technological systems were demonstrated on the example of development of a dialog-graphic system for studying the change in the fibre length in spinning and a dialog experimental-statistical system of adjusting process equipment in spinning. Moscow State Textile Academy. Translated fromKhimicheskie Volokna, No. 4, pp. 41–44, July–August, 1999.     

Selected chemical constituents and deer browsing preference of Douglas fir

Douglas fir foliage from eight full-sib F₁ families was analyzed for chlorogenic acid and essential oils and ranked according to browsing preference of penned black-tailed deer. Foliage was obtained during the dormant season, and tissues for both the preference test and chemical analyses were collected from the same trees. Deer ranked the different families, and chlorogenic acid content was correlated with preference order. Families varied significantly in yield and composition of essential oils, but differences were not related to preference. Results may have application in selections for Douglas fir resistant to browsing.     

New natural 2-acetoxy fatty acids using chemical ionization and electron impact mass spectrometry

The phospholipids of the spongePolymastia gleneni contain saturated long chain (C_22–30)-acetoxy fatty acids. Their structures were assigned based on chromatographic and spectrometric data as well as comparison with a synthetic sample. The use of capillary gas chromatography combined with chemical ionization and electron impact mass spectrometry was instrumental in the eludication of structures, since only a very small amount of crude lipids was available. Part 10 of “Phospholipids in Marine Organisms.” For Part 9 in this series, see reference 12.