КОНВЕКЦИЯ ВОЗДУХА В СНЕЖНОМ ПОКРОВЕ МОРСКОГО ЛЬДА (AIR CONVECTION IN SNOW COVER OF SEA ICE)

For the first time, data on stability of stationary convective filtration within infinite horizontal layer of snow covering the flat surface of floating ice is presented in this article. An analytical solution of the linearized problem was obtained with the use of the Galerkin method, and the parametric analysis of the problem was performed. It was found that the stability criteria (Rayleigh filtration numbers) obtained with consideration for the heat exchange of snow cover with the atmosphere did not exceed the known value of 4π2 for a horizontal porous layer with impermeable isothermal boundaries. As expected, the interaction with the atmosphere has the most significant impact on the critical Rayleigh numbers, while influence of variations in snow density and ice thickness and the thickness of the underlying layer of ice are small. Based on data of ice and meteorological observations made in the winter of 2015/16 in the Western part of the Laptev Sea together with calculations of the fast ice evolution, the values and temporal variability of temperature gradients and the Rayleigh numbers in the snow cover were obtained using a thermodynamic model. It was found that both, the model and observed magnitudes, exceeded their critical values determined by solving the stability problem. The conclusion is made that the convective regime of the heat transfer does really exist in the snow cover, and thus its contribution to the thermal and mass balance of sea ice during winter period should be taken into account

Contradictions in the Development of the Welfare Non-Profit Sector in Russia

Received 28 April 2023. Accepted 8 August 2023. Published online 6 October 2023.The article focuses on the core contradictions within the development of the social non-profit sector in Russia. The empirical basis of the study comprises statistical data, legal documents regulating the social services’ sphere, research data from previous studies conducted in Russia, as well as qualitative data collected for this study. The introduction provides background information on the stages of reforming the social service system in Russia. The first part is devoted to the contradictions between international trends and Russian patterns. In line with a neoliberal approach, non-profit NGOs play a significant role as key actors in social work providing social services for different client groups. At the same time, they are not independent and Russian civil society is not yet strong enough to realize social rights of citizens. In the next section, some of the key issues of interaction between the government and NGOs are discussed. An analysis of the current situation demonstrates that while a social partnership between the state and NGOs is affirmed by authorities on official level, in practice, the state still dominates the social sector. The article then focuses on how Russian NGOs have reoriented their efforts toward financial sustainability through government support.This work was supported by the Russian Science Foundation (RSF) under the project No. 19–18–00246-P, titled “Challenges of the transformation of welfare state in Russia: institutional changes, social investment, digitalization of social services”, implemented at St. Petersburg State University

Особенности текстуры многолетнего пресного льда в заливе Транскрипция (Восточная Антарктида) в период летнего таяния

The paper presents new data on the texture and density of a unique natural object – perennial fresh landfast ice in the Gulf of Transcription (East Antarctica), obtained in January 2020. The main purpose of the work was a planned (scheduled) inspection of the landing site selected for the 63rd season of the Russian Antarctic Expedition (RAE), investigation of the ice core sampling and analysis of its texture, including measuring the ice density. The thickness of the ice cover at the core sampling site was 3.02 m. In the long-standing (perennial) fast ice, the new ice is formed mainly from below as a natural growing of the congelation ice. From above a new ice is formed in smaller volumes, and it is either the infiltration ice in spring or freezing of melt water on the surface in autumn. Infiltration ice does not contribute much to the old fast ice, remaining a seasonal phenomenon. The reasons for that are insufficient snow accumulation in winter and the lack of salt water in the subglacial layer. In the upper layer of ice, its density is minimal and amounts to 680–720 kg/m3, increasing with depth and approaching its maximum at the lower edge – 917 kg/m3. The average density of ice is 875 kg/m3. The effect of primary air inclusions (bubbles) on the density of ice which contains large crystals of tens of centimeters in size is approximately the same for the whole ice thickness. Significant changes in the density of ice are caused by secondary inclusions which are formed during the freezing of melt water in the runoff and riverbed flows. It is shown how a crack in the ice, probably thermal, is further transformed under the influence of temperature and melt water runoff into a sinusoidal channel. This is rather common phenomenon associated with the thermal physics of the ice cover, the melting–freezing processes, and surface tension. The period of the sinusoid increases linearly with depth (the coefficient of determination R2 = 0.99). Thus, the new data obtained allows expanding the present-day scientific notions on the role of physical processes in formation and evolution of long-standing (perennial) ice.В январе 2020 г. на многолетнем пресном льду толщиной 3,02 м в заливе Транскрипция (Восточная Антарктида) – в районе полевой базы Оазис Бангера – был отобран керн, выполнен его текстурный анализ и измерена плотность льда. Исследование текстуры льда показало, что в многолетнем припае залива лёд формируется главным образом снизу с образованием конжеляционного льда естественного нарастания. Из-за недостаточного снегонакопления в зимний период и отсутствия солёной воды в подлёдном слое инфильтрационный лёд не вносит вклад в многолетний лёд, оставаясь сезонным явлением

Noise-induced broadening of a quantum-dash laser optical frequency comb

Single-section quantum dash semiconductor lasers have attracted much attention as an integrated and simple platform for the generation of THz-wide and flat optical frequency combs in the telecom C-band. In this work, we present an experimental method allowing to increase the spectral width of the laser comb by the injection of a broadband optical noise from an external semiconductor optical amplifier that is spectrally overlapped with the quantum dash laser comb. The noise injection induces an amplification of the side modes of the laser comb which acquire a fixed phase relationship with the central modes of the comb. We demonstrate a broadening of the laser comb by a factor of two via this technique.Comment: 4 pages, 4 figure

Erhöhung der Zuverlässigkeit der Bestimmung der Neutronenbelastung von WWER-Reaktorkomponenten zwecks Ableitung von Vorschlägen für eine sicherere Betriebsführung von WWER-Reaktoren

The results of a project sponsored by the German Bundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie are presented. The Project aimed to improve the safety against embrittlement of VVER-1000 type reactors by a more reliable and accurate determination of the neutron load of reactor pressure vessels. Therefore, six scientist from three Russian research institutions were sponsored to support with their work another BMBF project of the FZR aimed at the same goal. By providing reliable data for the evaluation of ex-vessel neutron activation experiments at two VVER-1000 and formulating the corresponding reactor models a basis has been established for further investigations as well in the FZR as well as in several Russian and Western research institutions. The leading Russian nuclear data library ABBN/MULTIC has been improved and tested. The uncertainties affecting the calculations of the fluence spectrum at the outer boundary of the pressure vessel have been analysed and a spectrum covariance matrix has been derived. The methodologies for the experimental determination of activation rates and for calculations of fluence spectra and activation rates have been further developed and tested by interlaboratoy comparisons. Measurements of different laboratories were compared with each other, as well as the corresponding calculations. Moreover, measurements and calculations were compared against each other, partly with participation of further Russian, Czech and Western institutes. The results of the Intercomparisons have been evaluated by the "International Workshop on the Balakovo-3 Interlaboratory Dosimetry Experiment" in September 1997 in Rossendorf. As a result of these works a better evaluation of the reached accuracies was possible and proposals for an improvement of the used methods could be derived

Методика перестроения маршрута полета воздушного судна в процессе его выполнения

   A significant number of aviation incidents is related to loss of control in flight and controlled flight into terrain (LOC-I, CFIT, LALT categories). Investigation of these aviation incidents has revealed that these incidents often occur due to the need for rapid changes in flight routes as a result of detecting obstacles, such as thunderstorms, along the aircraft's path. During the determination of alternative routes to circumvent the encountered obstacle, as well as during the implementation process of the chosen rerouted route, the flight crew makes errors due to increased psycho-physiological workload and time constraints. This article presents an approach to the automatic rerouting of the aircraft's flight route to avoid obstacles detected during flight. The algorithm proposed by the authors allows for evaluating the safety of the original route, calculating alternative route options to bypass the obstacles encountered during flight, verifying their feasibility considering the aircraft's flight technical characteristics and control parameter limitations, and selecting the optimal rerouted route based on specific criteria, such as minimizing the increase in the flight route length, reducing additional fuel consumption, time required for implementing the new flight route, etc. Examples of rerouting the flight route of a hypothetical aircraft with detected obstacles along the flight path are provided in the article to demonstrate the algorithm's functionality. It is shown, in particular, that in the considered example, the shortest route for obstacle avoidance is not optimal in terms of time. It is also demonstrated that the safety of flying along the identified alternative rerouted routes depends, among other factors, on the selected flight speed. Therefore, for each calculated rerouted route, the algorithm determines a range of speeds within which the implementation of the obtained rerouted route is possible. This highlights the complexity and non-triviality of the pilot's task of autonomously finding a safe obstacle avoidance route on board the aircraft.   Большое количество авиационных происшествий связано с потерей управления в полете, а также со столкновением с землей в управляемом полете (категории LOC-I, CFIT, LALT). В результате расследования данных авиационных происшествий выявлено, что часто указанные авиационные происшествия обусловлены необходимостью быстрого изменения маршрута полета вследствие выявления на пути следования воздушного судна препятствий, например, грозового фронта. При определении альтернативных маршрутов облета возникшего препятствия, а также впроцессе реализации выбранного маршрута облета экипаж совершает ошибки ввиду повышенной психофизиологической нагрузки и дефицита времени. В данной статье представлен подход к автоматическому перестроению маршрута полета воздушного судна для облета обнаруженных в процессе полета препятствий. Предлагаемый авторами алгоритм позволяет оценить безопасность исходного маршрута, рассчитать варианты альтернативных маршрутов облета обнаруженных впроцессе полета препятствий, проверить их на реализуемость с учетом летно-технических характеристик воздушного судна, ограничений на управляющие параметры, а также выбрать среди найденных маршрутов облета оптимальный с точки зрения какого-либо критерия, например, исходя из минимизации увеличения протяженности маршрута полета, сокращения дополнительных затрат топлива, времени, необходимого на реализацию нового маршрута полета, и т. д. Для демонстрации работоспособности алгоритма в статье представлены примеры перестроения маршрута полета гипотетического воздушного судна с выявленными на пути следования препятствиями. Показано, в частности, что в рассмотренном примере самый короткий маршрут облета препятствий не является оптимальным с точки зрения временных затрат. Также демонстрируется, что безопасность пролета по найденным альтернативным маршрутам облета препятствий зависит в том числе от выбранной скорости полета. Поэтому для каждого рассчитанного маршрута облета препятствий алгоритм определяет диапазон скоростей, в котором возможна реализация полученного маршрута облетапрепятствий. Последнее указывает на сложность и нетривиальность самостоятельного решения задачи поиска безопасного маршрута облета препятствий пилотом на борту воздушного судна

Припайный лёд в прибрежной части пролива Шокальского

Field investigations of coastal fast ice near the research station Ice Base on the «Cape Baranova», carried out in 2013–2014, made possible to reveal a number of characteristics of the sea ice cover formation. It has been shown that during winter and early spring the sea ice thickness, being formed due to intensive snow drift and caused by that flooding of the ice cover just near the coast of the Bolshevik Island, substantially grows at its upper boundary, that is typical for the Antarctic seas. At the same time, similar process of the ice growth at a relatively short distance from the coast shows all features characteristic for the ice cover in the Arctic seas, and that is well reproduced by the conceptual numerical sea ice model. Thus, the region of the Ice Base «Cape Baranova» represents a natural laboratory for studying the processes of the sea ice formation in both, the Arctic and Antarctic seas under condition of the same atmospheric forcing. Transformation of the fast ice structure during the summer time is described. Results of the investigations has demonstrated that despite the radical changes in the structure thicknesses of the fast ice remained almost unchanged due to the ice growth on the bottom boundary of the ice cover until a destruction of it in August.Приведены результаты исследований припайных льдов пролива Шокальского в районе научно‑исследовательского стационара «Ледовая база «Мыс Баранова». Установлена роль снежного покрова в процессах формирования ледяного покрова в зимний период, характерных как для арктических, так и антарктических морей. Описана трансформация структуры льда в летний период. Показано, что, несмотря на радикальное изменение структуры, толщина припайных льдов практически не изменяется вплоть до взлома припая в августе в результате нарастания льда на нижней границе ледяного покрова

Surgical methods of treatment of extrasphincter and transsphincteric fistulas of the rectum (literature review)

The aim of review. To present literature data on surgical treatment of extrasphincteric and transsphincteric fistulas of rectum.Key points. Treatment of fistulas of rectum remains a challenge because of risk of frequent relapses varying from 4,7 to 60%. Radical treatment methods are overly traumatic and result in severe fibrotic changes in the anal canal structures that are accompanied by high risk of anal sphincter incompetence - up to 83%. Now highly effective methods with application of various implants to eliminate tissue defect and improve regeneration are presented in the literature more and more commonly. Application of collagenic implants allows to decrease traumatization of sphincter fibres and thus to reduce to minimum risk of anal sphincter incompetence.Conclusion. Elimination of postoperative anal incontinence is a priority task in treatment of extrasphincter fistulas of rectum

Chayandinskoye field is the project of new technologies implementation in East Siberia

Modern level of study of structure of Chayandinskoye oil and gas condensate field is characterized by implementation of 3D seismic survey, carried out using a rich azimuth seismic survey system with a fold of 240. Complex seismic and geological conditions within this part of Eastern Siberia dictate high requirements to quality of field 3D seismic operations. A geological section of an area of operations is characterized by Lower Proterozoic formations of crystalline basement and Vendian, Cambrian, Jurassic, Quaternary deposits of the sedimentary cover. The main role in structure of the sedimentary cover is played by clastic and carbonate deposits of Vendian and halogen-carbonate formations of Cambrian Period. Productive part of a section refers to Botuobinsk, Khamakin and Talakh suits and is characterized by a very complex structure of natural reservoirs. Study of productive section structure is caused by need to prepare a field for production drilling and its subsequent development. In order to reveal features of structure of productive part of a section in a region with complex seismic and geological conditions, migration is used up to the summation in the deep region. Wide-azimuth observation system is aimed to study the most important challenges of medium structure such as direction and nature of change in fracture, study of azimuthal anisotropy of velocity characteristics of section and identification of characteristics of elastic properties change. Base technologies to study anisotropy of geological section properties are adapted and introduced into seismic exploration technique. They are as follows: 1) a method based on study of geometric attributes; 2) azimuthal analysis of velocities; 3) azimuth AVO-analysis (AVAZ); 4) anisotropic inversion. Based on results of processing and complex interpretation of seismic data of MOGT-3D works at the Chayandinskoye oil and gas condensate field the most important information about geological structure of sedimentary cover deposits and productive section was obtained. That allowed to significantly clarifying concept of structure of productive formations and geological development of this area. It also allowed determining distribution of reservoirs and evaluating reserves with considered new built structural and tectonic model