New Adsorption Cycle for Upgrading the Ambient Heat

Adsorption (chemical) heat transformation (AHT) is a new energy conservation and environmentally friendly technology that allows efficient use of heat sources with low temperature potential. Recently, a new cycle, called “Heat from Cold” (or HeCol) has been proposed to upgrade the temperature potential of the ambient heat. In the HeCol cycle, a natural reservoir of water with a temperature above 0°C is used as a heat source, and ambient air at T = (–20)–(–50)°C as a heat sink. The cycle is designed to produce heat at a temperature of 30–50°C, which can be used for heating of dwellings. The aim of this work is to select the adsorbent for the HeCol cycle and to test the laboratory prototype with the selected adsorbent. The work consists of three parts: (a) formulation of requirements to adsorbent, specialized for the HeCol cycles under various conditions; (b) analysis of data on adsorption equilibrium of commercial activated carbons and selection among them the materials suitable for the new cycle; and c) study of the laboratory prototype HeCol with the chosen adsorbent to analyze the feasibility of the new cycle. The main findings of this study are (i) the experimental demonstration of the HeCol cycle feasibility and (ii) the achievement of the specific heat generation power 8 kW/kg, which is of practical interest.     

Optical Diagnosis of the Geometry of an Axisymmetric Controlled Nozzle of a Gas-Turbine Engine

Modern aviation industry solves the problem of developing multifunction engines capable of flying both at subsonic and supersonic speeds. An important part in such engines is a variable area nozzle, which allows varying the geometry of the engine exhaust unit and, accordingly, its technical characteristics. This study touches upon an computer vision based optical noncontact method for reconstructing a nozzle shape. The reconstruction requires data recorded by two optical three-dimensional recorders directed toward the inner part of the nozzle when the engine is subjected to ground tests. The diagnosis is complicated by the presence of a hot jet being in the way of the sensor vision, the regime-dependent variation of the nozzle glow brightness, and intense mechanical vibrations. The performed bench tests confirm the efficiency of the proposed method. According to their results, in a low-gas regime, the standard deviation of the diagnosed diameters of the exhaust unit and critical sections for each frame does not exceed 0.3% of the corresponding sizes. The data obtained as a result of this diagnosis can be taken into account when upgrading the exhaust unit of the engine and the thrust control system of a gas turbine engine.

     

Change in molecular weight characteristics of an aromatic copolyamide during the polycondensation process

Conclusions The change in molecular weight characteristics and in viscosimetric data during the synthesis process of an aromatic copolyamide has been analyzed. It has been found that, with rise in the degree of completion of the reaction, at definite molecular weight values the dynamic viscosity rises sharply, which indicates the presence of a significant structural component of this system.The effect of polymer molecular weight on fibre physicomechanical properties has been shown. An increase in fibre strength has been noted on increase in molecular weight from 5400 to 7300. The impairment in physicomechanical properties on further increase in polymer molecular weight is connected with difficulties in processing the strongly structured spinning solutions. Processing polymer with a high molecular weight, and, as a consequence, with an elevated dynamic viscosity requires new approaches both to spinning conditions and, possibly, also to synthesis conditions.Translated from Khimicheskie Volokna, No. 2, pp. 29–30, March–April, 1989.     

Optimizing prior prediction accuracy for disturbances in guaranteed control problems

We consider and formalize the problem of finding optimal accuracy for prior prediction of disturbances in guaranteed planning problems under the assumption that there exist ready algorithms for processing observations able to increase prediction quality at some significant added costs. We analyze the general qualitative scheme of this problem and find analytic dependencies of optimal prediction quality for an illustrative problem of delivery planning. With the example of this problem, we show how useful it is to establish connections between different components in the disturbance vector. We propose a scheme of step-by-step increase in prediction accuracy that does not require prior knowledge of the prediction costs function.     

The pseudoeffect of the hydrogen chloride contained in the aramid fibres SVM, armos, and Rusar on their properties during prolonged storage and use

Data were obtained that indicate the elevated stability of the properties of SVM fibres during storage. The presence of even an important amount of HCl in the finished SVM fibres does not affect the subsequent performance characteristics. Rusor fibres, which have a lower HCI content, should have even more stable physicomechanical indexes during storage and use. __________ Translated from Khimicheskie Volokna, No. 6, pp. 7–9, November–December, 2006.