Высокоэффективная комбинированная теплопередающая система испарительно-конденсационного типа

Запропоновано конструкцію комбінованої теплопередающей системи випарно-конденсаційного типу, що складається з традиційної теплової труби і приєднаної до її зоні конденсації пластини, суміщеної з пульсаційної тепловою трубою, що дозволяє знизити загальний термічний опір системи і збільшити відводиться тепловий потік у порівнянні з теплопередающей системою, що складається з традиційної теплової труби і радіаторної пластиниThe design of combined heat-transfer system of evaporation-condensation type is proposed, consisting of traditional heat pipe and the plate united with pulsating heat pipe attached to its condensation zone. This design allows reducing the total thermal resistance and increasing the heat transfer rate of the system in comparison with the heat transfer system, consisting of traditional heat pipe and radiator plate.Предложена конструкция комбинированной теплопередающей системы испарительно-конденсационного типа, состоящая из традиционной тепловой трубы и присоединенной к ее зоне конденсации пластины, совмещенной с пульсационной тепловой трубой, позволяющая снизить общее термическое сопротивление системы и увеличить отводимый тепловой поток по сравнению с теплопередающей системой, состоящей из традиционной тепловой трубы и радиаторной пластины

Cryopumping of atomic hydrogen

The pumping speed for the cryopumping of an atomic hydrogen beam was measured. Measurements were made for cryocondensation, cryosorption, and differential pumping. The pumping speed for atomic hydrogen was observed to be much smaller than the pumping speed for molecular hydrogen. It is believed that this is due to the energy released during the recombination of the atomic hydrogen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69754/2/RSINAK-62-11-2738-1.pd

A Method for Magma Viscosity Assessment by Lava Dome Morphology

Lava domes form when a highly viscous magma erupts on the surface. Several types of lava dome morphology can be distinguished depending on the flow rate and the rheology of magma: obelisks, lava lobes, and endogenic structures. The viscosity of magma nonlinearly depends on the volume fraction of crystals and temperature. Here we present an approach to magma viscosity estimation based on a comparison of observed and simulated morphological forms of lava domes. We consider a two-dimensional axisymmetric model of magma extrusion on the surface and lava dome evolution, and assume that the lava viscosity depends only on the volume fraction of crystals. The crystallization is associated with a growth of the liquidus temperature due to the volatile loss from the magma, and it is determined by the characteristic time of crystal content growth (CCGT) and the discharge rate. Lava domes are modeled using a finite-volume method implemented in Ansys Fluent software for various CCGTs and volcanic vent sizes. For a selected eruption duration a set of morphological shapes of domes (shapes of the interface between lava dome and air) is obtained. Lava dome shapes modeled this way are compared with the observed shape of the lava dome (synthesized in the study by a random modification of one of the calculated shapes). To estimate magma viscosity, the deviation between the observed dome shape and the simulated dome shapes is assessed by three functionals: the symmetric difference, the peak signal-to-noise ratio, and the structural similarity index measure. These functionals are often used in the computer vision and in image processing. Although each functional allows to determine the best fit between the modeled and observed shapes of lava dome, the functional based on the structural similarity index measure performs it better. The viscosity of the observed dome can be then approximated by the viscosity of the modeled dome, which shape fits best the shape of the observed dome. This approach can be extended to three-dimensional case studies to restore the conditions of natural lava dome growth

Precision determination of band offsets in strained InGaAs/GaAs quantum wells by C-V-profiling and Schroedinger-Poisson self-consistent simulation

The results of measurements and numerical simulation of charge carrier distribution and energy states in strained quantum wells In_xGa_{1-x}As/GaAs (0.06 < x < 0.29) by C-V-profiling are presented. Precise values of conduction band offsets for these pseudomorphic QWs have been obtained by means of self-consistent solution of Schroedinger and Poisson equations and following fitting to experimental data. For the conduction band offsets in strained In_xGa_{1-x}As/GaAs - QWs the expression DE_C(x) = 0.814x - 0.21x^2 has been obtained.Comment: 9 pages, 12 figures, RevTeX

Spin-orbit interaction in three-dimensionally bounded semiconductor nanostructures

The structural inversion asymmetry-induced spin-orbit interaction of conduction band electrons in zinc-blende and wurtzite semiconductor structures is analysed allowing for a three-dimensional (3D) character of the external electric field and variation of the chemical composition. The interaction, taking into account all remote bands perturbatively, is presented with two contributions: a heterointerface term and a term caused by the external electric field. They have generally comparable strength and can be written in a unified manner only for 2D systems, where they can partially cancel each other. For quantum wires and dots composed of wurtzite semiconductors new terms appear, absent in zinc-blende structures, which acquire the standard Rashba form in 2D systems.Comment: 18 pages, 1 figur

Plan de actividades recreativas utilizando como medio el juego de balonmano adaptado, para los adolescentes entre 12 y 16 años del sexo masculino, de la circunscripción 117 El Batey de Sánchez, del Consejo Popular Las Ovas del municipio Pinar del Río

Este trabajo fue realizado en la circunscripción 117 “El Batey de Sánchez”, del Consejo Popular Las Ovas municipio Pinar del Río, el mismo surge debido a la carencia de actividades-físico recreativas destinadas a los adolescentes con edades comprendidas entre 12 y 16 años. Para su realización nos trazamos como problema científico el siguiente: ¿Cómo mejorar la recreación física en los adolescentes entre 12 y 16 años de edad del sexo masculino de la circunscripción 117 “El Batey de Sánchez”, del consejo popular las Ovas? el mismo surge por la problemática que presentan los adolescentes de esta circunscripción, dentro de los cuales podemos mencionar las peleas de gallos, perros, tomeguines, lo cual se pudo comprobar con la aplicación de los diferentes métodos utilizados en nuestro trabajo. Debido a la importancia del mismo nos propusimos el siguiente Objetivo: Aplicar un plan de actividades recreativas utilizando como medio el juego de balonmano adaptado para los adolescentes entre 12 y 16 años de edad del sexo masculino de la circunscripción 117 “El Batey de Sánchez”, del consejo popular Las Ovas municipio Pinar del Rió. Al final del mismo se presentan conclusiones y recomendaciones, las cuales dan respuestas a las interrogantes planteadas al comienz