The magnetic connectivity of coronal shocks from behind-the-limb flares to the visible solar surface during γ\gamma-ray events

Context. The observation of >100 MeV {\gamma}-rays in the minutes to hours following solar flares suggests that high-energy particles interacting in the solar atmosphere can be stored and/or accelerated for long time periods. The occasions when {\gamma}-rays are detected even when the solar eruptions occurred beyond the solar limb as viewed from Earth provide favorable viewing conditions for studying the role of coronal shocks driven by coronal mass ejections (CMEs) in the acceleration of these particles. Aims: In this paper, we investigate the spatial and temporal evolution of the coronal shocks inferred from stereoscopic observations of behind-the-limb flares to determine if they could be the source of the particles producing the {\gamma}-rays. Methods: We analyzed the CMEs and early formation of coronal shocks associated with {\gamma}-ray events measured by the Fermi-Large Area Telescope (LAT) from three eruptions behind the solar limb as viewed from Earth on 2013 Oct. 11, 2014 Jan. 06 and Sep. 01. We used a 3D triangulation technique, based on remote-sensing observations to model the expansion of the CME shocks from above the solar surface to the upper corona. Coupling the expansion model to various models of the coronal magnetic field allowed us to derive the time-dependent distribution of shock Mach numbers and the magnetic connection of particles produced by the shock to the solar surface visible from Earth. Results: The reconstructed shock fronts for the three events became magnetically connected to the visible solar surface after the start of the flare and just before the onset of the >100 MeV {\gamma}-ray emission. The shock surface at these connections also exhibited supercritical Mach numbers required for significant particle energization. [...] (Abridged)Comment: 20 pages, 15 figures, version published in A&

Continuous Dependence of Solutions of Quasidifferential Equations with Non-Fixed Time of Impulses

In this article on quasidifferential equation with non-fixed time of impulses we consider the continuous dependence of the solutions on the initial conditions as well as the mappings defined by these equations. We prove general theorems for quasidifferential equations from which follows corresponding results for differential equations, differential inclusion and equations with Hukuhara derivative

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

On shape optimization for compressible isothermal Navier-Stokes equations

The steady state system of isothermal Navier-Stokes equations is considered in two dimensional domain including an obstacle. The shape optimisation problem of drag minimisation with respect to the admissible shape of the obstacle is defined. The generalized solutions for the Navier-Stokes equations are introduced. The existence of an optimal shape is proved in the class of admissible domains. In general the solution to the problem under consideration is not unique

Urology

УЧЕБНО-МЕТОДИЧЕСКИЕ ПОСОБИЯУРОЛОГИЯУРОЛОГИЧЕСКИЕ БОЛЕЗН

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

Enhancement of construction of water chambers of network water heaters of steam turbine for combined heat and energy production

The report explores the possibility of using partitions of network heater chambers as anchor ties and examples of their design are presented. The results of calculations of such chambers are presented. Based on the results of these calculations, it is concluded that using the anchor partitions makes it possible to significantly reduce bending stresses in the bottom and tube plate, reduce the load on the flange connection, use a flat bottom instead of the elliptical one, significantly reduce the longitudinal stresses in the tubes, which increases the life of the most damageable heater element.В докладе рассматривается возможность использования перегородок водяных камер сетевых подогревателей в качестве анкерных связей и примеры их конструктивного исполнения. Приводятся результаты расчетов таких камер. По результатам этих расчетов сделаны выводы, что использование анкерных перегородок позволяет существенно уменьшить изгибные напряжения в днище и трубной доске, уменьшить нагрузку на фланцевое соединение, вместо эллиптического днища использовать плоское, существенно уменьшить продольные напряжения в трубках, что повышает ресурс самого повреждаемого элемента подогревателя

Ansys multiphysics simulation applying for work blade near steam extraction

В статье ставится задача применения междисциплинарного анализа при расчете околоотборных ступеней паровых турбин. На основе опубликованных работ описываются проблемы, которые необходимо решать при расчете и проектировании лопаточного аппарата. Описывается необходимость разработки унифицированной методики прочностного расчета рабочих лопаток околоотборных ступеней.The purpose of this work is ansys multiphysics simulation applying for work blade near steam extraction. The problems that must be addressed in calculation and design of blading describes on the basis of published works. The development applicability of standardized methods of work blade strength calculation is describe