Method for the Optimal Design of Vacuum-Evaporative Heat Pumps

A method is developed for optimally designing vacuum-evaporative heat pumps that use water (R718) as a refrigerant. This method is based on the autonomous method of the thermoeconomic optimization of thermodynamic systems, and makes it possible, when optimizing the design and choosing economical modes of system operation, to simultaneously take into account both thermodynamic and economic parameters.На базі автономного методу термоекономічної оптимізації термодинамічних систем розроблена методика оптимального проектування вакуумно-випарних теплових насосів, що використовують воду (R718) як холодоагент. Ця методика дозволяє під час оптимізації конструкції і вибору економічних режимів роботи системи одночасно враховувати як термодинамічні, так і економічні параметри.На базе автономного метода термоэкономической оптимизации термодинамических систем разработана методика оптимального проектирования вакуумно-испарительных тепловых насосов, использующих в качестве хладагента воду (R718). Эта методика позволяет при оптимизации конструкции и выборе экономичных режимов работы системы одновременно учитывать как термодинамические, так и экономические параметры

Processing Behavior of Electrodes Made with Addition of Nanopowder

The study analyzes the processing behavior of welding electrodes made with addition of nanopowder, and compares them to standard welding electrodes (without addition of nanopowder). The effect of nanopowder of complex composition on the electrode metal transfer process is analyzed as well

ЭФФЕКТЫ РЕАЛЬНОЙ И МОДЕЛИРУЕМОЙ МИКРОГРАВИТАЦИИ НА НЕКОТОРЫЕ СТРУКТУРНО-МЕТАБОЛИЧЕСКИЕ ПАРАМЕТРЫ СКЕЛЕТНЫХ МЫШЦ

The aim of present publication is summarization of experimental results on real and modeled effects of zero gravity on the impellent device of a man and other mammals. In particular, its effects on high-speed and power characteristics of skeletal muscles depending on their metabolic activity are analyzed. В настоящей работе обобщены результаты экспериментов с реальными и моделируемыми эффектами невесомости на двигательный аппарат человека и других млекопитающих. В частности, проанализировано ее влияние на скоростно-силовые характеристики скелетных мышц в зависимости от их метаболической активности.

Effect of physical exercises and perceived stress interaction on students’ satisfaction with life

Purpose : to find out the effect of regular physical exercises and perceived stress interaction on students’ satisfaction with life. Material and methods : The study involved university students (n = 355; М age = 19,97; SD = 2,12). The moderator analysis was conducted according to the cross-sectional questionnaire. Results : It is determined that the difference in students' satisfaction with life at the average and high perceived stress is due to physical exercises. The influence of the interaction of variables (physical activity x perceived stress) on satisfaction with life was statistically significant. Conclusions : It is revealed the peculiarities of interaction between the physical exercises and perceived stress. The reduce of satisfaction with life under the influence of perceived stress is more typical for those students who do not regularly practice physical exercises. Physical exercises act as a buffer against stress

Electron-optical system of 200 kV gun for the VEPP-5 preinjector

The electron gun with a new electron-optical system to match project parameters of the VEPP-5 preinjector is described. The gun produces the current with 10 A amplitude, pulse duration 2...3 ns at half-height and electron energy 200 keV. The gun has a dispenser cathode 20 mm in diameter and 100 mm spherical radius. The current control is performed by means of molybdenum equipotential grid with the cell size 0.4·0.4 mm and optical transparency of about 0.68. The experimental results obtained are in good agreement with project parameters.Описано електронну гармату з новою електронно-оптичною системою, що відповідає проектним параметрам передінжектора VEPP-5. Гармата дає струм 10 А с тривалістю імпульсу 2...3 нс на напіввисоті і з енергією електронів 200 кеВ. Гармата має диспергуємий катод діаметром 20 мм і радіусом сфери 100 мм. Керування здійснюється за допомогою молібденової еквіпотенційної сітки з коміркою розміром 0.4·0.4 мм і оптичною прозорістю близько 0.68. Експериментально отримані результати знаходяться у відповідності з проектними параметрами.Описана электронная пушка с новой электронно-оптической системой, соответствующая проектным параметрам предынжектора VEPP-5. Пушка дает ток 10 А с длительностью импульса 2…3 нс на полувысоте и с энергией электронов 200 кэВ. Пушка имеет диспергируемый катод диаметром 20 мм и сферическим радиусом сферы 100 мм. Управление осуществляется посредством молибденовой эквипотенциальной сетки с ячейкой размером 0.4·0.4 мм и оптической прозрачности около 0.68. Экспериментальные полученные результаты находятся в хорошем соответствии с проектными параметрами

Diagnostics of evolution of risk collapse complications at student group with anomalous cardiovascular reaction

The description of investigation of predisposition to potential danger of collapse complications at 429 first-year students during physical training is presented using the analysis of pulse wave form. With the help of developed device the group of students with predisposition to risk of collapse complications during physical activity has been revealed. The results of clinical examination have confirmed the predisposition of the given group to risk of collapse complication

Discrete skew selfadjoint canonical systems and the isotropic Heisenberg magnet model

A discrete analog of a skew selfadjoint canonical (Zakharov-Shabat or AKNS) system with a pseudo-exponential potential is introduced. For the corresponding Weyl function the direct and inverse problem are solved explicitly in terms of three parameter matrices. As an application explicit solutions are obtained for the discrete integrable nonlinear equation corresponding to the isotropic Heisenberg magnet model. State space techniques from mathematical system theory play an important role in the proofs

Transverse instability and its long-term development for solitary waves of the (2+1)-Boussinesq equation

The stability properties of line solitary wave solutions of the (2+1)-dimensional Boussinesq equation with respect to transverse perturbations and their consequences are considered. A geometric condition arising from a multi-symplectic formulation of this equation gives an explicit relation between the parameters for transverse instability when the transverse wavenumber is small. The Evans function is then computed explicitly, giving the eigenvalues for transverse instability for all transverse wavenumbers. To determine the nonlinear and long time implications of transverse instability, numerical simulations are performed using pseudospectral discretization. The numerics confirm the analytic results, and in all cases studied, transverse instability leads to collapse.Comment: 16 pages, 8 figures; submitted to Phys. Rev.