Remote testing of high-voltage insulators

An integrated two-channel method has been suggested for remote testing of operating condition of high-voltage insulators. The method is based on concurrent registration and computer processing of partial-discharge signals that are detected by electromagnetic and acoustic sensors. Using the device that was created based on this method, diagnostic signs have been established that make it possible to distinguish between functional and faulty insulators under real service conditions.     

Mechanochemical synthesis of a hydroxycarbonate form of layered magnesium aluminum hydroxides

Mechanical activation of a mixture of magnesium hydroxide, aluminum hydroxide, and sodium bicarbonate in an AGO-2 planetary mill, followed by water washing leads to the formation of a layered magnesium aluminum hydroxide. The double hydroxide obtained at a magnesium hydroxide to aluminum hydroxide ratio of 3:1 is essentially phase-pure and contains both carbonate and bicarbonate ions in its interlayer spaces. The synthesized double hydroxide was characterized by x-ray diffraction, IR spectroscopy, thermogravimetry, differential thermal analysis, and chemical analysis.     

Addition of CCl<Subscript>4</Subscript> to olefins catalyzed by chromium and ruthenium complexes: The influence of water as a nucleophilic additive

The feasibility of the addition of CCl₄ to linear and cyclic olefins and dienes in the presence of chromium and ruthenium complexes was established. The influence of water as a nucleophilic additive and the influence of the olefin nature, the catalyst central atom, and its ligand environment on the reaction selectivity and product yields were investigated. It was shown that the addition of water to chromium and ruthenium catalysts leads to the hydrolysis of the chloromethyl group in the resulting 1,1,1,3-tetrachloro derivatives, yielding the corresponding hydroxy derivatives and increasing the selectivity for the formation of (1 + 1) adducts, which is caused by the formation of hypochlorous acid playing the role of a coactivator of the addition of CCl₄ to alkenes.     

Construction of an Optimal Relational Schema for Storing XML Documents in an RDBMS without Using DTD/XML Schema

The goal of this work is to construct an optimal relational schema for storing XML documents in a relational database (RDBMS) with the possibility of subsequently processing their elements without using information about the structure of these documents (such as DTD, XML Schema, and so on). A survey of the currently available methods for solving this problem is given, and the most promising among them from the standpoint of processing large arrays of documents are selected. Then, the methods selected are refined and modified, and, on the basis of these methods, a system for storing XML documents in an RDBMS is constructed. Finally, the performance of this system for each method considered is tested, and, by the results of these tests, an optimal relational schema is selected.     

Study and Development of the DTD Generation System for XML Documents

Principles of constructing systems for generating DTDs for a collection of XML documents are discussed. Methods and algorithms for creating DTDs are developed. A DTD generation system for a collection of XML documents is developed. This system can efficiently be used both for solving applied problems and for theoretical studies.__________Translated from Programmirovanie, Vol. 31, No. 4, 2005.Original Russian Text Copyright © 2005 by Leonov, Khusnutdinov.     

A Study of the Absorption of Nitrogen Oxides from the Boiler Flue Gases

In the past decade, the number of unsolved ecological problems has been steadily increasing. Among the numerous causes of this situation, the exposure of the environment to industrial waste should be mentioned. For example, enterprises of the fuel and energy industry emit a significant amount of hazardous substances into the atmosphere. Flue gases formed in boiler-houses and at thermal power stations get through flue gas stacks into the upper atmosphere and pollute it. In this work, a method is proposed for adsorption treatment of the flue gases from boilers fired with associated petroleum gas. The chemical composition of the associated petroleum gas of Romashkino oil field, the Republic of Tatarstan, is presented and the practicality of its use is demonstrated. Nitrogen oxides contained in the boiler flue gases result from oxidation of molecular air nitrogen during combustion of the fuel. In order to reduce the adverse effect of hazardous substances on the environment, the flue gases are to be compulsorily cleansed of nitrogen oxides. The use of the sludge resulting from coagulation and liming of natural water during the chemical water treatment at Kazan CHPP-1 as a sorption material is proposed. The chemical composition and technical characteristics of the sludge are presented. The properties of the sludge were studied using a laboratory fixed-sorbent-bed setup. The sorption capacity and water-absorption of the sludge were determined and curves of the kinetic and isothermal dependences of the nitrogen oxide adsorption by the sludge were constructed. The change in the nitrogen- oxide sorption capacity of the sludge depending on the sludge particle size was established. The optimal characteristics of a batch-type fixed-bed absorber were calculated. The results of calculating the economic and ecological effects of introducing the adsorption treatment of flue gases to remove nitrogen oxides for the boiler-house of AO Karpov Chemical Plant are provided.     

Synthesis of 2-thiophenecarboxylic and 2,5-thiophenedicarboxylic acid esters via the reaction of thiophenes with the CCl<Subscript>4</Subscript>-ROH reagent in the presence of vanadium,iron, and molybdenum catalysts

2-Thiophenecarboxylic and 2,5-thiohenedicarboxylic acid esters were synthesized via the reaction of thiophene with the CCl₄-ROH-catalyst system, with a total yield of 44–85%. A possible reaction scheme includes the successive steps of alkylation of thiophene with carbon tetrachloride, leading to 2-trichloromethylthiophene, and alcoholysis of the product giving the corresponding 2-thiophenecarboxylate. The best catalysts for this reaction are VO(acac)₂, Fe(acac)₃, and Mo(CO)₆.     

Solvent Dehydration and Separation of Native Asphalt

A combined process for dehydration, deasphalting, and acetone fractionation of Ashal'chinsk native asphalt was developed and investigated. Technology was proposed for combined solvent preparation and separation of natural asphalt and the basic characteristics of the process were determined. The technical and economic indexes of the proposed and traditional technologies were compared.     

Preparation of ZnO heterolayers on zinc chalcogenide substrates

A process is described for the preparation of ZnO heterolayers on single-crystal zinc chalcogenide (ZnTe, ZnSe, and ZnS) substrates via isovalent substitution.