Results of numerical modeling of collisionless diffusion induced by electrostatic fluctuations

Collisionless particle transport is considered on the base of interaction of plasma particles with wave packets arising as a result of the overlap of many wave modes. Results of calculation of diffusion coefficients are presented for different plasma parameters and parameters of magnetic configuration (plasma temperature, magnetic field value, wave amplitudes, etc.). Low frequency and lower hybrid drift waves are considered. Diffusion coefficients coefficients are obtained as results of averaging over sets of particle trajectories and particle energies.Беззіштовхувальна дифузія розглядається з позиції взаємодії частинок плазми й хвильових пакетів , що виникають внаслідок перекриття багатьох хвильових мод. Для різних значень параметрів плазми й магнітної конфігурації (температури плазми, значення магнітного поля, амплітуди хвиль тощо) представлені результати розрахунків коефіцієнтів дифузії. Коефіцієнти дифузії були отримані в результаті усереднення по траєкторіям та енергіям частинок.Бесстолкновительная диффузия рассматривается на основе взаимодействия частиц плазмы и волновых пакетов, возникающих в результате перекрытия многих волновых мод. Для различных значений параметров плазмы и магнитной конфигурации (температура плазмы, величина магнитного поля, амплитуды волн и т.д.) представлены результаты расчетов коэффициентов диффузии. Коэффициенты диффузии были получены в результате усреднения по траекториям и энергиям частиц

Particle transport: model of non-stationary fluctuations

Particle dynamics in non-uniform magnetic field for a slab and a cylinder is presented. The presence of electric field with low frequency drift (LFD) and lower hybrid drift (LHD) waves is considered. Drift waves as the possible cause of an anomalous transport in plasma are used in calculations. Non-stationary fluctuations of the electrostatic field of the plasma waves are modeled. The stochastization of the particles is studied numerically

Increasing the corrosion resistance of welded joints of heat-resistant nickel alloy with steel

For parts and assemblies of a turbopump unit (TPU) and a liquid rocket engine, welded joints of steel and heat-resistant alloys are used. Considering that the search for replacements by several materials at once, the study of their mutual compatibility in a product takes considerable time and money. Therefore, it would be better to replace it with one alloy, and the unification of the material used allowed the structure to work as a whole. After exploring various options, the substitutes for research were selected inconel 718.Для виготовлення деталей і вузлів турбонасосного агрегату (ТНА) і рідинного ракетного двигуна застосовуються зварні з'єднання з корозійно-стійкими сталями і жароміцними сплавами, які вимагають різних режимів термічної обробки для досягнення рівня механічних властивостей, зазначених у конструкторськой документації. З огляду на те, що пошук заміни відразу декількох матеріалів, їх відпрацювання у виробництві і дослідження взаємної сполучності при температурно-силових впливах у виробі, може зайняти значний час і кошти, найкращою була б заміна на один сплав, а уніфікація застосовуваного матеріалу дозволила конструкції працювати як єдине ціле, що підвищило б технологічність виробів. Після вивчення різних варіантів заміни, для дослідження було обрано inconel 718.Для изготовления деталей и узлов турбонасосного агрегата (ТНА) и жидкостного ракетного двигателя применяются сварные соединения с коррозионно-стойкими сталями и жаропрочными сплавами, требующие разные режимы термической обработки для получения уровня механических свойств, обозначенных в конструкторской документации. Учитывая, что поиск замены сразу нескольких материалов, их отработка в производстве, исследование взаимной сочетаемости при температурно-силовых воздействиях в изделии может занять значительные время и средства, то наилучшей была бы замена на один сплав, а унификация применяемого материала позволила конструкции работать как единое целое и повысила бы технологичность изделий. Изучив разные варианты замены, для исследований был выбран inconel 718

Experimental study of injector based on the spark source with titanium cathode saturated with hydrogen

The results of experimental study of short-pulse proton injector for various variants of construction of pulse spark ion source are considered. The experimental results of study of regimes of both ignition and discharge support within the source with stabilized pulse feeding (~10 μs, 5 Hz). Of special concern the increasing of the cathode electrode lifetime. The results ofmeasurements ofboth absolute and partial (in spices) density ofion beam are presented.Представлені результати іспитів короткоімпульсного інжектора протонів для різних варіантів виконання конструкції імпульсного іскрового джерела. Приводяться експериментальні результати відпрацьовування оптимальних режимів порушення і підтримки розряду в джерелі зі стабілізованим імпульсним живлення (~ 10 мкс, 5 Гц).Представлены результаты испытаний короткоимпульсного инжектора протонов для различных вариантов выполне- ния конструкции импульсного искрового источника. Приводятся экспериментальные результаты отработки оптимальных режимов возбуждения и поддержания разряда в источнике со стабилизированным импульсным питанием (~ 10 мкс, 5 Гц)

Carbon stocks and CO2 emissions of urban and natural soils in Central Chernozemic region of Russia

C-sequestration, as a function of soils, is known to help mitigate climate change. However, the potential of urban soils to be C-sinks or sources, is widely unknown. This study aims to understand the role and significance of urban soils in the C-balance of the region. It reveals several important findings about the C-balance capacities of urban soils and the multiple factors affecting this balance. This two-year study focused on soil organic carbon (SOC) stocks and CO2 emissions of urban soils in the city of Kursk, located in the Central Chernozemic region of Russia, an area known to have some of the most fertile soils in the world. SOС stocks and emissions were studied in residential, recreational, and industrial functional zones and in comparison to corresponding natural reference soils to analyze the influence of urbanization on C turnover Urban soils were found to store 20 to 50 kg С m− 2 in 1.5 m layer; 10–30% less than in corresponding natural Luvic Chernozems and Chernic Phaeozems, but greater than what has been reported for many other cities. The urban soils with developed cultural layers stored more C in subsoil compared to the natural soils. Emissions of CO2 in urban soils, however, were higher than from Chernic Phaeozems but comparable to those from Luvic Chernozems. The CO2/SOC stocks ratio in urban soils was two–three times higher than in natural soils. These outcomes point to the intensive C turnover and low sustainability of SOC stocks in urban soils. This study found evidence that the recent urbanization of the Chernozemic region has adversely affected the C balance. Natural soils in the region are important C sinks, however they can convert to C sources in result of urbanization

Carbon stocks and CO2 emissions of urban and natural soils in Central Chernozemic region of Russia

C-sequestration, as a function of soils, is known to help mitigate climate change. However, the potential of urban soils to be C-sinks or sources, is widely unknown. This study aims to understand the role and significance of urban soils in the C-balance of the region. It reveals several important findings about the C-balance capacities of urban soils and the multiple factors affecting this balance. This two-year study focused on soil organic carbon (SOC) stocks and CO2 emissions of urban soils in the city of Kursk, located in the Central Chernozemic region of Russia, an area known to have some of the most fertile soils in the world. SOС stocks and emissions were studied in residential, recreational, and industrial functional zones and in comparison to corresponding natural reference soils to analyze the influence of urbanization on C turnover Urban soils were found to store 20 to 50 kg С m− 2 in 1.5 m layer; 10–30% less than in corresponding natural Luvic Chernozems and Chernic Phaeozems, but greater than what has been reported for many other cities. The urban soils with developed cultural layers stored more C in subsoil compared to the natural soils. Emissions of CO2 in urban soils, however, were higher than from Chernic Phaeozems but comparable to those from Luvic Chernozems. The CO2/SOC stocks ratio in urban soils was two–three times higher than in natural soils. These outcomes point to the intensive C turnover and low sustainability of SOC stocks in urban soils. This study found evidence that the recent urbanization of the Chernozemic region has adversely affected the C balance. Natural soils in the region are important C sinks, however they can convert to C sources in result of urbanization. © 201

Carbon stocks and CO2 emissions of urban and natural soils in Central Chernozemic region of Russia

C-sequestration, as a function of soils, is known to help mitigate climate change. However, the potential of urban soils to be C-sinks or sources, is widely unknown. This study aims to understand the role and significance of urban soils in the C-balance of the region. It reveals several important findings about the C-balance capacities of urban soils and the multiple factors affecting this balance. This two-year study focused on soil organic carbon (SOC) stocks and CO2 emissions of urban soils in the city of Kursk, located in the Central Chernozemic region of Russia, an area known to have some of the most fertile soils in the world. SOС stocks and emissions were studied in residential, recreational, and industrial functional zones and in comparison to corresponding natural reference soils to analyze the influence of urbanization on C turnover Urban soils were found to store 20 to 50 kg С m− 2 in 1.5 m layer; 10–30% less than in corresponding natural Luvic Chernozems and Chernic Phaeozems, but greater than what has been reported for many other cities. The urban soils with developed cultural layers stored more C in subsoil compared to the natural soils. Emissions of CO2 in urban soils, however, were higher than from Chernic Phaeozems but comparable to those from Luvic Chernozems. The CO2/SOC stocks ratio in urban soils was two–three times higher than in natural soils. These outcomes point to the intensive C turnover and low sustainability of SOC stocks in urban soils. This study found evidence that the recent urbanization of the Chernozemic region has adversely affected the C balance. Natural soils in the region are important C sinks, however they can convert to C sources in result of urbanization. © 201