ОПТИМИЗАЦИЯ ФОРМЫ ФЮЗЕЛЯЖА, НАПРАВЛЕННАЯ НА УМЕНЬШЕНИЕ АЭРОДИНАМИЧЕСКОГО СОПРОТИВЛЕНИЯ КОМПОНОВКИ «КРЫЛО - ФЮЗЕЛЯЖ» ПРИ СВЕРХЗВУКОВЫХ СКОРОСТЯХ

The problem of fuselage shape optimization of the wing-body configuration is considered in the following three formulations. In the first one, the angle of attack is fixed and equal to zero, the wing has a symmetric airfoil, and the fuselage is based on circular cross sections. In the second one, the fuselage cross sections are elliptical. In the third one, the angle of attack is varied, the lifting force coefficient is fixed, the wing is preliminary optimized, the fuselage is designed by the cross sections that consist of upper and lower half-ellipses with a possibility of a shift along vertical axis. The configuration volume, fuselage length, shape and position of the wing are fixed. The drag coefficient is the objective function. The optimization is carried out by the Indirect Optimization based on Self-Organization (IOSO) technology. Aerodynamic coef- ficients are obtained from the solution of the RANS equations with SST turbulence model by the ANSYS CFX software on the structured multiblock meshes. The results obtained by the optimization are compared with the configuration that is designed by traditional means. The fuselage of this configuration has a cylindrical part in the area of the wing-fuselage connection and nose part of the von Karman’s ogive shape. The solution of the optimization problem in the first formulation reduces drag coefficient at zero angle of attack by approximately 3 %. The use of the fuselage with elliptical cross sections makes it possible to reduce drag coefficient at zero angle of attack by 9 %. The solution of the optimization problem in first two formulations reduces drag coefficient at the wide range of angles of attack. When the lifting coefficient is selected for the third problem formulation as constraint the drag reduction is about 7 %. Additional drag reduction of about 2,5 % is obtained by the use of the fuselage asymmetric relative to the horizontal plane. The optimal fuselage design has a specific grotto in the lower part of the fuselage - the constriction from the sides with continuing height growth. The nose part of the optimal fuselage is widened, has a triangular shape in the top view and is deflected down.В работе рассмотрена оптимизация формы фюзеляжа в конфигурации «крыло - фюзеляж». Рассмотрено три постановки задачи. В первой угол атаки зафиксирован и равен нулю, крыло имеет симметричный профиль, а фюзеляж задается круговыми сечениями. Во второй фюзеляж задается эллиптическими сечениями. В третьей угол атаки варьируется, коэффициент подъемной силы зафиксирован, крыло предварительно оптимизировано, а фюзеляж задается сечениями, состоящими из верхнего и нижнего полуэллипсов с возможностью смещения сечения вдоль вертикальной оси. Во всех постановках задачи объем компоновки, длина фюзеляжа, форма и положение крыла, форма первого и последнего сечений фюзеляжа зафиксированы. В роли целевой функции выступает коэффициент сопротивления. Оптимизация проведена с помощью непрямого метода оптимизации, основанного на самоорганизации. Аэродинамические коэффициенты получались в результате решения уравнений Рейнольдса с замыканием по модели турбулентности SST в коммерческом программном пакете Ansys CFX на структурированных многоблочных расчетных сетках. Результаты оптимизации сравниваются с конфигурацией, спроектированной традиционным образом. Фюзеляж этой конфигурации имеет цилиндрический участок в области стыка с крылом и носовую часть в виде оживала Кармана. Решение задачи оптимизации в первой постановке снижает коэффициент сопротивления компоновки «крыло - фюзеляж» при нулевом угле атаки примерно на 3 %. Использование фюзеляжей эллиптического сечения позволяет снизить коэффициент сопротивления на нулевом угле атаки на 9 %. Решение задач оптимизации в первых двух постановках позволяет снизить сопротивление в широком диапазоне углов атаки. При коэффициенте подъемной силы, выбранном для третьей постановки задачи в качестве ограничения, величина уменьшения сопротивления составляет порядка 7 %. Дальнейшее снижение сопротивления за счет использования вариации формы фюзеляжа, несимметричной относительно горизонтальной плоскости, составляет порядка 2,5 %. При этом фюзеляж оптимальной конфигурации имеет характерный подфюзеляжный «грот» - поджатие с боков при продолжающемся нарастании высоты. Носовая часть оптимального фюзеляжа расширена, имеет треугольную форму в плане и отклонена вниз

Very high quality factor measured in annealed fused silica

We present the results of quality factor measurements for rod samples made of fused silica. To decrease the dissipation we annealed our samples. The highest quality factor that we observed was $Q=(2.03\pm0.01)\times10^8$ for a mode at 384 Hz. This is the highest published value of $Q$ in fused silica measured to date.Comment: 8 pages, 2 figure

Effect of thickness on the piezoelectric properties of LiNbO3 films

The results were obtained using the equipment of Research and Education Center and the Center of collective use “Nanotechnology” of Southern Federal University

The influence of Losartanum and Amlodipinum fixed combination use on cardiovascular complications risk factors seasonal variability in patients with arterial hypertension

Rationale: The influence of drugs on adaptation to high temperatures and seasonal variability of cardiovascular disease factors is one of the most important issues of treatment raised during re-cent heat waves. The safety of calcium channel blockers (CCBs) and angiotensin II receptor blockers (ARBs) use during heat waves is quite controversial. Aim: To assess the seasonal variability of hemodynamic parameters, vessel wall stiffness, lipid, carbohydrate and electrolyte metabolism in patients with arterial hypertension (AH) and to as-sess safety and effectiveness of fixed combination of Losartanum and Amlodipinum (Lortenza® KRKA) use according to one-year follow-up results. Materials and methods. The study included 26 patients with stage 1 and 2 AH aged from 42 to 81 years. Office blood pressure measurement, electrocardiography, volumetric sphygmography (pulse-wave velocity, cardio-ankle vascular index), serum chemistry, blood osmolarity tests were performed. Visual Analog Scale (VAS), Heat Questionnaries and self-control diaries were also assessed. The baseline visit took place in spring of 2016, the first visit - in May-June 2016, the second - during the heat wave, the third - in September-October 2016, the fourth - in January-February 2017, and the fifth - in April-May 2017. Results. The treatment resulted in systolic and diastolic blood pressure decrease (р=0.000) to target value which persisted during the follow-up period. According to the self-control diaries 81% of patients did really control BP. During the heat wave only 58% of patients succeeded in BP control, in autumn - 63%, in winter and spring - 81% and 86%, respectively. By the third visit the heart rate decreased on -6.0 (-11.1; -2.8) beats per minute, p=0.007. The decrease in pulse-wave velocity from 15.2±3.4 m/s to 13.6±2.7 m/s, p=0.01 and CAVI on -2.1 (-2.9; -0.65), p=0.01 was observed on the third visit. Decrease in uric acid level (

INCREASING THE ENERGY, ENVIRONMENTAL AND ECONOMIC EFFICIENCY OF NUCLEAR POWER PLANT

The paper presents a method for reducing energy consumption for auxiliary needs of a nuclear power plant by creating models of equipment for auxiliary systems, analyzing and improving its operation modes. Neural network modeling technologies and their analogues are considered as the main tool for solving the set tasks. The application of the work results during the modernization of existing units and during the design of new equipment will increase the efficiency of electric power generation at the power unit of the power plant.В работе представлен способ снижения затрат энергии на собственные нужды атомной электрической станции путем создания моделей оборудования систем собственных нужд, анализа и совершенствования режимов его эксплуатации. В качестве основного инструмента решения поставленных задач рассмотрены технологии нейросетевого моделирования и их аналоги. Применение результатов работы при модернизации существующих агрегатов и в ходе проектирования нового оборудования позволит повысить эффективность выработки электрической энергии на энергоблоке станции

Role of portocaval shunts in development of complications after liver transplantation

Rationale. Portal blood flow is a key component in the viability of the liver transplant. Portocaval shunts formed on the background of the liver cirrhosis before transplantation can cause portal vein steal syndrome, with subsequent development of ischemic necrosis of the graft. To date, the tactics of treating patients with portal vein steal syndrome during liver transplantation has not been sufficiently developed. This paper presents a literature review and our own experience on this important, but little-studied issue. Purpose. The purpose of this research is to study the role of portocaval shunts in the development of complications after liver transplantation, based on a retrospective analysis of clinical cases. Conclusions. In liver transplantation, portocaval shunts can cause the development of portal vein steal syndrome with subsequent development of liver failure. For the diagnosis of portal vein steal syndrome, it is important to use the data obtained at all stages of liver transplantation. Surgical correction of portal vein steal syndrome can be performed during liver transplantation and in the early postoperative period. © 2022 by the authors

Increasing the Efficiency of the NPP Turbine Feed Pump by Improving Hydraulic Characteristics

В работе представлен начальный этап проекта, направленного на повышение эффективности действующего оборудования АЭС путём точного определения проблемных зон и устранения их недостатков. Повышение эффективности осуществляется на основе вывода рекомендаций нейросетевой модели, работающей в реальном времени.The paper presents the initial stage of the project aimed at improving the efficiency of existing NPP equipment by accurately identifying problem areas and eliminating their shortcomings. Efficiency improvement is carried out based on the output of recommendations of a neural network model operating in real time.Работа подготовлена в рамках выполнения НИОКР по до говору № 9/326176-Д от 29.10.2021 с АО «Концерн Россэнергоатом».The work was written in the framework of R&D under contract No. 9/326176-D dated October 29, 2021with JSC «Concern Rossenergoatom»

Generic representations of abelian groups and extreme amenability

If $G$ is a Polish group and $\Gamma$ is a countable group, denote by \Hom(\Gamma, G) the space of all homomorphisms $\Gamma \to G$. We study properties of the group \cl{\pi(\Gamma)} for the generic \pi \in \Hom(\Gamma, G), when $\Gamma$ is abelian and $G$ is one of the following three groups: the unitary group of an infinite-dimensional Hilbert space, the automorphism group of a standard probability space, and the isometry group of the Urysohn metric space. Under mild assumptions on $\Gamma$, we prove that in the first case, there is (up to isomorphism of topological groups) a unique generic \cl{\pi(\Gamma)}; in the other two, we show that the generic \cl{\pi(\Gamma)} is extremely amenable. We also show that if $\Gamma$ is torsion-free, the centralizer of the generic $\pi$ is as small as possible, extending a result of King from ergodic theory.Comment: Version