The solution of elements in the molten system AlCl3-NaCl

The solubility of Hg, P, Mn, W, Mo, Cu, Si and S in molten 1:1 AlCl3 - NaCl was measured to 150-370 deg. Except with S, there is no chemical reaction between the solutes and the solvent

The shock-acoustic waves generated by earthquakes

We investigate the form and dynamics of shock-acoustic waves generated by earthquakes. We use the method for detecting and locating the sources of ionospheric impulsive disturbances, based on using data from a global network of receivers of the GPS navigation system and requiring no a priori information about the place and time of associated effects. The practical implementation of the method is illustrated by a case study of earthquake effects in Turkey (August 17, and November 12, 1999), in Southern Sumatera (June 4, 2000), and off the coast of Central America (January 13, 2001). It was found that in all instances the time period of the ionospheric response is 180-390 s, and the amplitude exceeds by a factor of two as a minimum the standard deviation of background fluctuations in total electron content in this range of periods under quiet and moderate geomagnetic conditions. The elevation of the wave vector varies through a range of 20-44 degree, and the phase velocity (1100-1300 m/s) approaches the sound velocity at the heights of the ionospheric F-region maximum. The calculated (by neglecting refraction corrections) location of the source roughly corresponds to the earthquake epicenter. Our data are consistent with the present views that shock-acoustic waves are caused by a piston-like movement of the Earth surface in the zone of an earthquake epicenter.Comment: EmTeX-386, 30 pages, 4 figures, 3 tabl

Overview of V.A. Plotnikov’s research on averaging of differential inclusions

In this review, we will first look in detail at Plotnikov’s results on the substantiation of full and partial schemes of averaging of differential inclusions of the standard form on finite and infinite intervals. Then we will consider the algorithms where it is not possible to find the average, but there is a possibility to find its estimation from below and from above. Such an approach is also used when the average can be found only approximately. This situation is common for differential inclusions with fast and slow variables. In the end, we will present the results on the substantiation of the full and partial averaging methods for impulsive differential inclusions on finite and infinite intervals

Method of Averaging for Impulsive Differential Inclusions

AMS subject classification: Primary 49N25, Secondary 49J24, 49J25.The paper deals with impulsive differential inclusions in the euclidean space. The main purpose is to justify the method of averaging in the case of bounded and asymptotically small impulses. The obtained results, which are based on the condition of an integral continuity, generalize the first Bogoljubov’s theorem for the method of averaging.This work is partially supported by Grant No MM 807/98 of the Bulgarian Ministry of Education and Science

Analysis Of Characteristics Of A 5 Kw Power Plant Based On Solid Oxide Fuel Cells In Four Modes

The paper presents the results of testing a 5 kW power plant based on solid oxide fuel cells (SOFC) with natural gas serving as fuel, equipped with a steam reformer combined with a burner. It includes a diagram of the power plant and a result analysis procedure based on heat and mass balances elaborated for the reformer, SOFC stack, catalytic burner and heat exchanger. The experimental findings were used to calculate the actual ratios of fuel utilization, oxygen consumption from cathode air in the electrochemical generator using two methods (heat and energy balances and Faraday’s law). A comparison of the results of the two methods revealed a small error, which was observed mainly in the second mode (60%). Parameters of the power plant by ‘UIC’ LLC were reviewed at four steady running modes: 40% of SOFC’s power utilization (2 kW), 60% (3 kW), 90% (4.5 kW) and at the peak mode of 110% (5.4 kW), where the consumption exceeds the rated power by 10%. Calculation of the equilibrium composition of conversion products, at temperatures (t3) registered at the reformer’s outlet, allowed the formula for the natural gas reforming reaction to be obtained. A simplified method of calculating the composition of the natural gas steam reforming products is described; the results are compared with calculations made in the program Gaseq, using the software package Mathcad for the solution of nonlinear equations. Analysis of the results showed the effectiveness of a simplified method at temperatures above 800°C; in that temperature range, this method has an error of less than 0.5%, which is sufficient for using in practice

Numercial simulation of flow in a exhaust hood of steam turbine Т-6376-8,8

The paper considers the main stages of modeling process of working fluid in the exhaust hood of a steam turbine T-63/76-8.8. The analysis of calculation results is carried out, the coefficient of total losses is determined, the zones of non-optimal flow are identified.В работе рассматриваются основные этапы моделирования процесса течения рабочего тела в выхлопном патрубке паровой турбины Т-63/76-8,8. Выполняется анализ результатов расчёта, определяется коэффициент полных потерь, выявляются зоны неоптимального течения рабочего тела

Complex analysis and statistics of emergency shutdowns of gas turbines at compressor stations

The problems of monitoring the state of the gas compressor station, the main causes of emergency shutdowns, the urgency of measures to extend the life of parts and assemblies, the creation of repair bases near compressor stations are considered. The authors proposes the creation of a program for monitoring the residual resources of parts and assemblies, planning repair, analyzing the parameters of the gas turbine before and after repair, as well as evaluating the effectiveness of its operation.Рассматриваются проблемы мониторинга состояния ГПА, основные причины аварийных остановов, актуальность проведения мероприятий по продлению ресурса деталей и узлов, создание ремонтных баз вблизи компрессорных станций. Авторы предлагают создание программы для мониторинга остаточных ресурсов деталей и узлов, планирования ТОиР, анализа параметров работы ГПА до и после ремонта, а так же оценки эффективности её работы

Economic efficiency estimation of using the supercapacitors in the gearless syhchronous electric drive of the passenger elevator

Рассматривается использование суперконденсаторов в безредукторном электроприводе на основе низкоскоростного синхронного двигателя с возбуждением от постоянных магнитов. Представлены результаты математического моделирования, а также экономический анализ целесообразности использования емкостных накопителей в механизме пассажирского лифта.Using of ultracapacitors in the gearless electric drive based on the low-speed synchronous motor with permanent magnets excitation is considered. Results of mathematical simulation, the economic practicability analysis of ultracapacitors applying in the passenger elevator mechanism are provided

Operational development of piston engines by mathematical modeling of working process

В статье представлены результаты математического моделирования рабочего процесса поршневого двигателя внутреннего сгорания размерности 8,2/7,1. Математическое моделирование выполнялось в программном комплексе Дизель-РК, разработанном в МГТУ имени Н.Э. Баумана. Показано влияние показателей качества газообмена на технико-экономические показатели поршневого двигателя. Установлено, что доводка впускной и выпускной систем оказывает значительное влияние на основные показатели двигателя. За счет изменения конфигурации газовозудушных трактов двигателя можно увеличить его мощность вплоть до 11 % при увеличении удельного расхода топлива лишь на 0,5-1,5 %.The results of mathematical modeling of working process of the internal combustion engine (dimension 8,2/7,1) are presented in the paper. Mathematical modeling was performed in the software Diesel-RK developed in MSTU named after N. Uh. Bauman. The influence of quality indicators of gas exchange on technical and economic indicators of the engine are presented in the article. Operational development of the intake and exhaust systems has a significant impact on the basic performance of the engine. Changes to the configuration of the air-gas path of the engine increases power up to 11 % at simultaneous increase of specific fuel consumption of only 0.5 to 1.5 %.Работа выполнена при поддержке РФФИ (грант мол_а, договор № 16-38-00004\16)