Propagation of rotational waves in a block geomedium

On the base of assumption that the rotational movements of the chain of the crust blocks and the corresponding rotational waves characterizing the redistribution of tectonic stresses are described by the sine-Gordon equation with dissipation, the dispersion properties of this equation are analyzed. It is shown that the dispersion is manifested in the low-frequency range at high values of the dissipation factor. The presence of anomalous dispersion has been revealed for all values of the dissipation factor. Influence of this factor on dispersion is investigated. Some features of propagation of a stationary shock wave in a geomedium are studied. It has been found that the shock wave front width is directly proportional to the nonlinear wave velocity and to the dissipation factor of the medium, but it is inversely proportional to the nonlinearity coefficient

Global gyrokinetic simulations of intrinsic rotation in ASDEX Upgrade Ohmic L-mode plasmas

Non-linear, radially global, turbulence simulations of ASDEX Upgrade (AUG) plasmas are performed and the nonlinear generated intrinsic flow shows agreement with the intrinsic flow gradients measured in the core of Ohmic L-mode plasmas at nominal parameters. Simulations utilising the kinetic electron model show hollow intrinsic flow profiles as seen in a predominant number of experiments performed at similar plasma parameters. In addition, significantly larger flow gradients are seen than in a previous flux-tube analysis (Hornsby et al {\it Nucl. Fusion} (2017)). Adiabatic electron model simulations can show a flow profile with opposing sign in the gradient with respect to a kinetic electron simulation, implying a reversal in the sign of the residual stress due to kinetic electrons. The shaping of the intrinsic flow is strongly determined by the density gradient profile. The sensitivity of the residual stress to variations in density profile curvature is calculated and seen to be significantly stronger than to neoclassical flows (Hornsby et al {\it Nucl. Fusion} (2017)). This variation is strong enough on its own to explain the large variations in the intrinsic flow gradients seen in some AUG experiments. Analysis of the symmetry breaking properties of the turbulence shows that profile shearing is the dominant mechanism in producing a finite parallel wave-number, with turbulence gradient effects contributing a smaller portion of the parallel wave-vector

Low resistance Cu[3]Ge compounds formation by the lowtemperature treatment of Cu/Ge system in atomic hydrogen

The research deals with the regularities for Cu[3]Ge compound formation under the low temperature treatment of a double-layer Cu/Ge system deposited on i-GaAs substrate in atomic hydrogen flow. The treatment of a Cu/Ge/i-GaAs system with layer thicknesses, respectively, of 122 and 78 nm, in atomic hydrogen with a flow rate of 10{15} at.·сm{-2} s{-1} for a duration of 2.5{-10} min at room temperature, leads to an interdiffusion of Cu and Ge and formation of a polycrystalline film containing stoichiometric phase Cu[3]Ge. The film consists of vertically oriented grains of dimensions 100-150 nm and has a minimum specific resistance of 4.5 [mu omega] сm. Variation in the treatment duration of Cu/Ge/i-GaAs samples in atomic hydrogen affects Cu and Ge distribution profiles, the phase composition of films formed, and the specific resistance of the latter. As observed, Cu3Ge compound synthesis at room temperature demonstrates the stimulative effects characteristic of atomic hydrogen treatment for both Cu and Ge diffusion and for the chemical reaction of Cu[3]Ge compound generation. Activation of these processes can be conditioned by the energy released during recombination of hydrogen atoms adsorbed on the surface of a Cu/Ge/i-GaAs sample

Non-sinusoidal magnetoelastic waves in structural members

The paper discuses propagation of longitudinal waves in a homogeneous nonlinear superconducting rod placed in strong magnetic field. By using the nonlinear Bishop model the equations of magnetoelasticity for the rod performing longitudinal oscillations has been derived. The evolution of nonlinear magnetoelastic waves is studied. As a result the conditions of formation of intense periodic magnetoelastic waves and magnetoelastic solitons are established

Double-sided arc welding with multiple electrodes of vertical joints of steel tanks

The increase of the welding productivity is still of immediate interest, which in turn requires the development and implementation of more high-performance welding methods that ensure a consistently high quality of welded joints. One of the ways to further increase the productivity of arc welding processes in the construction of tanks is the industrial use of automatic double-sided arc welding with multiple electrodes in separate weld pools. To establish the relationship between the parameters of the welding mode, energy characteristics, as well as the distance between the torches and their angle of inclination relative to the groove, a physical and mathematical model of the production of the welding joint when four arcs participate in pairs from both sides of the joint has been developed. Thus, computer modeling showed that during weld formation with the movement of the electrode down (vertical down), the possibility of supplying each pair of arcs with pulsed current should be taken into account. During groove filling with the movement of the electrodes up (vertical up), their lateral oscillations and delays at the edges should be carried out according to an aperiodic law in order to minimize the effects of 'magnetic blow'. © Published under licence by IOP Publishing Ltd

ПРОЕКТИРОВАНИЕ CИCТЕМЫ НАДДУВА ДЛЯ ИCПЫТАНИЙ МАЛОРАЗМЕРНОГО ГАЗОТУРБИННОГО ДВИГАТЕЛЯ C ПУЛЬCИРУЮЩИМ ДЕТОНАЦИОННЫМ МОДУЛЕМ

One of the promising ways to boost the gas turbine engine is to install a pulse detonation module in the exhaust case. Research on the effectiveness of the developed module in the expenditure thermal vacuum chamber, providing a complete simulation of these terms and conditions, requires unique equipment, as well as the significant financial and oper- ating costs. Accordingly ,it is more efficient to conduct performance and effectiveness assessment of the pulse detonation module using the existing test rigs, modified to partially simulate flight conditions comprising: a platform with the studied gas turbine engine (GTE), a power plant on a movable platform, pressurization system pipeline from an auxiliary power unit (APU) to the test engine, fuel and electrical systems of the test rig. The article presents small-size GTE pressurization system design results. The pipeline design is based on the conditions of mutual arrangement of the studied GTE and APU test cell. The choice of design solutions for production and assembly of components of the pressurization system, and the results are presented algorithm and calculating geometrical parameters ejector providing the required pressure and air flow temperature at the inlet to the studied engine. As a result, the research reasonably determined the structural diagram of the boost system test rig, providing a partial simulation of flight conditions at the inlet to the small-sized turbine engine. There were defined the necessary geometry and gas-dynamic properties of the gas ejector, the use of which as part of test rig pres- surization system will start the series of studies, according to the pulse detonation performance of the module.Одним из перспективных способов форсирования газотурбинного двигателя является установка в его затурбинное пространство пульсирующего детонационного модуля. Проведение исследований по оценке эффективности разрабатываемого модуля в расходной термобарокамере, обеспечивающей полную имитацию данных условий, требует наличия уникального оборудования, а также значительных финансовых и производственных затрат. Представляется более рациональным в связи с этим проведение первоочередных исследований по оценке работоспособности и эффективности пульсирующего детонационного модуля осуществлять в условиях сущеcтвующих испытательных стендов, доработанных для частичной имитации полетных условий и включающих: платформу с исследуемым газотурбинным двигателем (ГТД), энергоустановку на подвижной платформе, трубопровод системы наддува, обеспечивающий подачу воздуха от вспомогательной силовой установки (ВСУ) к исследуемому двигателю, топливную и электрическую системы стенда. В статье представлены результаты работ по проектированию системы наддува для малоразмерного ГТД. Трубопровод спроектирован исходя из условий взаимного расположения, исследуемого ГТД и ВСУ в испытательном боксе. Обоснован выбор конструктивных решений для изготовления и монтажа составных частей системы наддува, представлены алгоритм и результаты расчета газодинамических и геометрических параметров эжектора, обеспечивающего необходимые давление и температуру воздушного потока на входе в исследуемый двигатель. В результате проведенных исследований обоснованно определена конструктивная схема системы наддува испытательного стенда, обеспечивающего частичную имитацию полетных условий на входе в малоразмерный ГТД. Определены необходимые геометрические и газодинамические параметры газового эжектора, применение которого в составе системы наддува испытательного стенда позволит начать комплекс исследований по оценке работоспособности пульсирующего детонационного модуля

Building Heat-insulating Materials Based on the Products of the Transesterification of Polyethylene Terephthalate and Dibutyltin Dilaurate

In this paper, we offered a technological basis for production of heat-insulating polyurethane materials based on the aromatic polyester - the product of transesterification of polyethylene terephthalate and corrective additive - dibutyltin dilaurate. Also, we presented the formulation and properties of the developed polyurethanes

Crystal field and exchange interactions in the SmFe3(BO 3)4 multiferroic

The optical spectra of oriented SmFe3(BO3) 4 single crystals are studied in the region of the f-f transitions in the Sm3+ ion by Fourier spectroscopy. The energies, the symmetry properties, and the exchange splittings of the Stark sublevels of the ground and 17 excited multiplets of the Sm3+ ion in a crystal field of symmetry D 3 are determined from the measured temperature dependences of polarized-radiation absorption spectra. The parameters of the crystal field acting on samarium ions and the parameters of the exchange interaction between Sm3+ and Fe3+ ions are found. The anisotropy of the effective exchange interaction is shown to be substantially stronger than the magnetic anisotropy, due to a strong crystal-field-induced mixing of the ground and excited multiplets. © 2014 Pleiades Publishing, Inc