Original Russian Text © M.A. Gotovskiy, M.I. Grinman, V.I. Fomin, V.K. Aref'ev, A.A. Grigor'ev, 2012, published in Teploenergetika. 236 Problems of achieving better energy efficiency and more efficient use of waste heat from energy intense production processes are nowadays very pressing ones. Considerable experience with construction of waste heat recovery systems has been gained at Ormat, Sie mens, Turboden, and other companies; however, real efficiencies of cycles that are implemented are limited to around 18%.The problem of rationally using energy resources has attracted great attention of specialists since the middle of the past century, the time when rapid growth of industrial production generated the need to make it more energy efficient. In many industries generating by products and fuel (e.g., black leach and wood in the pulp and paper industry, synthesis gas in the petroleum refining indus try, light gas mixtures obtained as a result of processing chemical substances, blasting gases in steel industries, etc.) it is possible to avoid losses of energy by utilizing it in one form or another. The problems of losses in systems using renewable sources of energy (solar, geo thermal, and wind energy) for generating electricity are usually considered separately.Losses exist also in energy conversion systems (e.g., in heat exchangers, industrial heaters, pumps, and motors), the efficiency of which is limited by thermal or mechanical factors.Of course, heat losses-i.e., the produced heat that could not be usefully utilized by the consumer and was rejected into the environment-occupy the main place in the wide spectrum of energy losses. It should be noted that more than 75% of industrial heat wastes have temperature below 800 K, due to which applica tion of usual technologies, e.g., the Rankine steamwater cycle, for producing electricity is inefficient. THE ORGANIC RANKINE CYCLEThere are a few basic technologies using which low temperature waste heat can be utilized. For exam ple, for the last 20 years energy has been generated on the basis of the organic Rankine cycle (ORC) at power stations with capacities ranging from 300 kW to 130 MW operating on different sources of heat [1, 2]. Other alternative versions are either technically impossible or economically inefficient. Leading pro ducers of ORC based installations have gained great experience from using low boiling organic substances for producing electricity and have demonstrated that this cycle is well suited for low temperature sources of heat. The ORC technology is applicable for recovering heat of medium size gas turbines (GTs), cement plants, and geothermal sources, and yields consider able advantages as compared with the use of low tem perature steam turbines. The majority of existing sys tems operating at higher temperatures are fitted with a recovery unit (Fig. 1) between the heat source itself and organic working fluid (e.g., high temperature oil). The efficiency of electricity generaton using recovered heat of industrial wastes in ORC based systems...
Temperate tularemia bacteriophage was for the first time isolated from the organs of guinea-pig infected with live tularemia vaccine strain N 15 of RIEH line. Negative colonies of bacteriophage were up to 0.2 mm in diameter with incomplete lysis zone at the periphery. In view of the results of electronic microscopy bacteriophage represented filamentous carpuscules. Bacteriophage lyzed bacteria of three subtypes of tularemia etiological agent and bacteria of the main species of legionellosis etiological agents. The simple use of bacteriophage allows to recommend new tularemia bacteriophage GAL for practical application.
The article describes a hardware and software complex designed for defectoscopy and study of material properties. Sections of high-strength steel 08G2B pipes were scanned in the course of the research. The purpose of this study is to determine dependency of eddy current sensor signal and mechanical and operational properties of the base metal (K65 steel grade) and demonstrate the ability of developed eddy current probe to detect continuity defects and corrosion in this type of metal. The steel is ultra-low-carbon, which makes it possible to study their properties using the eddy current method. The eddy current method is a non-contact one being used both for cracks identification and determination of their characteristics. A special superminiature eddy current probe was developed, which includes three coils - stabilizing, measuring and exciting. The coils were placed on a pyramid-shaped core made of alloy 81NMA. The eddy-current transducer runs under the control of the developed hardware-software complex with a system for suppression of noise and amplification of signal received from the eddycurrent transducer. Signal processing makes it possible to separate the effects of closely spaced cracks on the eddy-current transducer signal and evaluate the contribution of each crack separately. As a parameter containing information about the presence of defects in the object of control, the voltage arrived at the measuring coil of the eddy current probe signal was used. The work studied sections of pipes with model continuity defects – cracks and holes. A research that allows to simulate the presence of corrosion in the metal was also conducted. The extreme values of the eddy current probe signal over defects of different types are obtained at various velocity, that allows to identify the type of defect, while changing the frequency of the signal on the probe allows to determine the depth of the defect.
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