Investigation of characteristics and modernization of the design exhaust tract gas turbine and gas compressors units.

The project considers the main elements of design of exhaust tract gas turbine and gas compressors units and their influence on the flow of exhaust gases. The methods for reducing the hydraulic losses in exhaust units are mentioned.В работе рассматриваются основные элементы конструкции выхлопного тракта газотурбинного и газоперекачивающего агрегата и влияние их на характер течения уходящих газов. Приводятся методы снижения гидравлических потерь в выхлопных патрубках агрегатов

Digitalization of the agro-industrial complex in the Russian Federation: Current status and development prospects

The article is concerned with the current state of digitalisation of the agro-industrial complex (AIC) in the Russian Federation. It lists a number of legal instruments that have been approved by the legislative authorities and establish the digitalisation trends of the agro-industrial complex at the federal and regional level

Sequence Stratigraphy and Onlap History of the Donets Basin, Ukraine: Insight into Carboniferous Icehouse Dynamics

The degree to which Permo-Carboniferous cyclothemic successions archive evidence for long-term variations in ice volume during the Late Paleozoic Ice Age is insufficiently resolved. Here we develop the sequence stratigraphy and onlap-offlap history for a 33-my interval of the Carboniferous using the U-Pb calibrated succession of the Donets Basin, Ukraine, in order to assess the relationship between sea-level, high-latitude changes in glacial extent, and climate. Integrated subsurface and outcrop data permit meter-scale correlation of 242 biostratigraphically constrained limestones and coals, and in turn individual cyclothems, across ~250 km of the Donets Basin. Rapid uniform subsidence and basinwide continuity of marker beds indicate Pennsylvanian deposition under relatively stable tectonic conditions. Three scales of sequences (avg. durations of ~140 ky, ~480 ky and 1.6 my) are recognized on the basis of stratigraphic stacking patterns and basinwide architecture of marine to terrestrial facies assemblages. The hierarchy of sequences and the geographic and stratigraphic positions of shifts in base-level sensitive facies across the Donets ramp permit the construction of an onlap-offlap history at a sub-400 ky scale. Major sea-level lowstands occur across the mid-Carboniferous boundary and during the early Moscovian. These lowstands coincide with glacial maxima inferred from high-latitude glacigenic deposits. The middle to late Pennsylvanian is characterized by a stepwise onlap, culminating in an earliest Gzhelian highstand, suggesting contraction of Carboniferous ice sheets prior to the initiation of Early Permian glaciation. The stratigraphic position of climate sensitive facies within individual Donets cyclothems indicates a turnover from seasonal sub-humid or semi-arid climate to everwet conditions during the late lowstand and maximum ice sheet accumulation. Comparison of the stratigraphic and aerial distribution of coals and evaporites in the Donets Basin with the onlap-offlap history further indicates everwet conditions during lowstands and inferred glacial maxima and drier climate during onlap and inferred ice sheet contraction at the intermediate (~0.8 to 1.6 my) and long (106 yr) time-scales. Taken together, the relationship between inferred climate and glacioeustasy suggests a likely teleconnection between high-latitude ice sheet behavior and low-latitude atmospheric dynamics

Energy and Technological Aspects of the Combustion of Ionized Gas-Dispersed Systems

This paper discusses the flame ionization effect on the combustion processes in gaseous suspensions of the dispersed fuels. It is shown that the two-phase flame ionization affects almost all the processes of the fuel conversion – kinetics of the dispersed fuel combustion, processes of the interphase heat and mass transfer, processes of the nucleation and coagulation in the flame, formation of nanoscale products of the metal particles combustion. It is shown that the electrostatic interaction between the charged nanoparticles and ions or polar molecules in the gaseous phase leads to the appearance of molecular “pumps” that can signifi cantly change the kinetics of the heterogeneous chemical reactions and the heat exchange between particles and gas. The influence of the thermal ionization of the flame on the nucleation mechanism and rate in gas-dispersed systems is discussed. The possibility of a barrier-free homogenous and heterogeneous nucleation in the dusty flame of metallic particles is shown. The effect of electrostatic and polarizing interactions of ions and molecules on the kinetics of the ternary gas-phase reactions is considered. The influence of the monodisperse aerosol ionization degree on the kinetics of its coagulation is analyzed. It is concluded that electrostatic interaction between the particles strongly affects the inhibition of the coagulation process in gas-phase combustion products and the possibility of very fast (explosive) charged particle coagulation of monodisperse aerosols. The possibility of the targeted size of metal oxides nanoparticles control, controlled ionizing of dusty flames and the role of ion particle entrainment, the dependency of their size of the flame ionization degree are discussed. Some effects arising in complex plasma of condensed combustion products under its own electric fi elds in flames, also when the burning dust is entrained into a constant electric field and their practical applications for diagnosis are considered

Investigation of characteristics and modernization of the design of exhaust tract gas turbine and gas compressors units

The project considers the main elements of design of exhaust tract at gas turbine and gas compressors units and their influence on the flow of exhaust gases. The methods for reducing the hydraulic losses in exhaust units are mentioned.В работе рассматриваются основные элементы конструкции выхлопного тракта газотурбинного и газоперекачивающего агрегата и влияние их на характер течения уходящих газов. Приводятся методы снижения гидравлических потерь в выхлопных патрубках агрегатов

Иерархическая кластеризация как метод снижения размерности в задаче оптимизации инвестиционного портфеля Марковица

Optimal portfolio selection is a common and important application of an optimization problem. Practical applications of an existing optimal portfolio selection methods is often difficult due to high data dimensionality (as a consequence of the large number of securities available for investment). In this paper, a method of dimension reduction based on hierarchical clustering is proposed. Clustering is widely used in computer science, a lot of algorithms and computational methods have been developed for it. As a measure of securities proximity for hierarchical clustering Pearson pair correlation coefficient is used. Further, the proposed method’s influence on the quality of the optimal solution is investigated on several examples of optimal portfolio selection according to the Markowitz Model. The influence of hierarchical clustering parameters (intercluster distance metrics and clustering threshold) on the quality of the obtained optimal solution is also investigated. The dependence between the target return of the portfolio and the possibility of reducing the dimension using the proposed method is investigated too. For each considered example in the paper graphs and tables with the main results of the proposed method - application which are the decrease of the dimension and the drop of the yield (the decrease of the quality of the optimal solution) - for a portfolio constructed using the proposed method compared to a portfolio constructed without the proposed method are given. For the experiments the Python programming language and its libraries: scipy for clustering and cvxpy for solving the optimization problem (building an optimal portfolio) are used.Составление оптимального портфеля ценных бумаг является важным и частым случаем решения задачи оптимизации. Практическое применение существующих методов составления оптимального портфеля часто затруднено из-за большого числа доступных для инвестирования ценных бумаг (и, как следствие, большой размерности исходных данных). В данной работе предлагается метод снижения размерности исходных данных, основанный на иерархической кластеризации доступных для инвестирования ценных бумаг. Для кластеризации, широко используемой в компьютерных науках, уже разработано множество алгоритмов и методов. В качестве меры близости ценных бумаг для иерархической кластеризации используется коэффициент парной корреляции Пирсона. Далее исследуется влияние предложенного метода на качество получаемого оптимального решения на нескольких примерах составления оптимального портфеля ценных бумаг по модели Марковица. Также исследуется влияние параметров иерархической кластеризации (метрики межкластерного расстояния и порогового значения кластеризации) на изменение качества получаемого оптимального решения. Исследуется зависимость между целевой доходностью портфеля и возможностью снижения размерности с помощью предложенного метода. Для каждого рассмотренного примера приводятся графики и таблицы с основными полученными результатами применения метода — понижением размерности и падением доходности (снижением качества оптимального решения) у портфеля, построенного с применением предложенного метода по сравнению с портфелем, построенным без применения предложенного метода. Для проведения экспериментов используется язык программирования Python и его библиотеки: scipy для проведения кластеризации и cvxpy для решения задачи оптимизации (построения оптимального портфеля)

Dialectics and Implications of Natural Neurotropic Autoantibodies in Neurological Disease and Rehabilitation

The role of natural idiotypic (Id-Abs) and anti-idiotypic (AId-Abs) autoantibodies against neuro-antigens observed in different neurological disorders is not fully understood. In particular, limited experimental evidence has been provided concerning the qualitative and quantitative serological response after acute injuries of the central nervous system or during chronic mental diseases. In this study, we analyzed the specific Id-Abs and AId-Abs serological reactivities against 4 neuro-antigens in a large population of patients with ischemic stroke, schizophrenia, as well as healthy individuals. Patients with ischemic stroke were tested at different time points following the acute stroke episode and a correlation was attempted between autoantibodies response and different patterns of functional recovery. Results showed variable and detectable Id-Abs and AId-Abs in different proportions of all three populations of subjects. Among patients with different functional recovery after ischemic stroke, a difference in time-related trends of Id-Abs and AId-Abs was encountered. Our observations suggest that changes in the production of natural neurotropic Abs may engender a positive homeostatic, beside a possible pathogenic effect, in specific neurological disorders

ФОРМУВАННЯ ГАЗОМЕТАЛЕВОГО ПОТОКУ В УМОВАХ «ХІМІЧНОГО» ВАКУУМУ У СТАЛЕВИПУСКНОМУ КАНАЛІ

The results of laboratory research to determine the hydro-gas-dynamic patterns the formation of gas-metal flow at an tapping from an oxygen converter to steel ladle are given due to the injection of subsonic argon jets into the melt flow through nozzles located in the steel-tapping channel.Using the method of low-temperature simulation, determined the influence of design parameters of the proposed design of a two-chamber steel-tapping channel (length of the reaction zone, the number and location of gas nozzles) and gas consumption on the degree of organization and protection of the gas-liquid flow (GLF) when the gas blowing into the working space of the steel-tapping channel.Was obtained mathematical relation characterizing the mutual influence on the opening angle of the GLF between of the relative length of the "reaction zone" (x) and the gas flow rate through the nozzle. It is shown that when the length of the "reaction zone" decreases, an extremum occurs at lower gas consumption, and the value of "subcritical" gas consumption has a greater range. So, when the length of the "reaction zone" decreases, an extremum occurs at lower gas consumption, and the value of "subcritical" gas consumption has a greater range.The possibility of retaining the angle of disclosure of the gas-liquid flow (α) in the range of up to 5° with a relative length of the reaction zone of 0,75 has been proved. It is shown that with an increase of α from 1...3° to 10°, the efficiency of the protective action of argon (k) decreases from 0,99 to 0,72. At x = 0,75, the coefficient k is in the range of 0,89...0,99. It is established that when the critical gas flow is exceeded and x = 0,25, the value of α rises to an inadmissible 10...15°.The classification of the purges of the melt flow in the steel-tapping channel is proposed, depending on the angle of inclination of the gas jets relative to the axis of the last (γ) in accordance with which are allocated: the mode of "interruption" (γ > 78°), at which the gas jets unclosed, the formation of the gas-liquid flow does not occur; the mode of "closing" (0  78°), при якому газові струмені розімкнуті, формування газорідинного потоку не відбувається; режим «змикання» (0 < γ < 78°), при якому газові потоки об’єднані, формується газорідинний потік з розвиненою міжфазною поверхнею і високим ступенем організації, та режим «пробою» (γ = 0°), при якому подальше збільшення витрати газу, що перевищує критичну, призводить до пробою і руху газорідинного потоку у дисперсно-кільцевому режимі із зменшенням ступеня організації потоку