Sustainment of High-Beta Mirror Plasma by Neutral Beams

The report presents two experiments carried out in Budker Institute for obtaining the maximum plasma beta (ratio of the plasma pressure to magnetic field pressure) in axially symmetric magnetic field. The experiments are based on injection of powerful focused neutral beams with high neutral power density in the plasma. The produced fast ion population significantly increases the plasma pressure. It the axially symmetric GDT experiment (Gas Dynamic Trap) the plasma beta exceeded 0.6 at the fast ion turning points. The CAT experiment (Compact Axisymmetric Toroid) is being prepared for obtaining a plasmoid with extremely high diamagnetism in axially symmetric magnetic field. Reversal of magnetic field in the plasmoid is possible in this experiment

Analytical Solution for the Current Distribution in Multistrand Superconducting Cables

Current distribution in multistrand superconducting cables can be a major concern for stability in superconducting magnets and for field quality in particle accelerator magnets. In this paper we describe multistrand superconducting cables by means of a distributed parameters circuit model. We derive a system of partial differential equations governing current distribution in the cable and we give the analytical solution of the general system. We then specialize the general solution to the particular case of uniform cable properties. In the particular case of a two-strand cable, we show that the analytical solution presented here is identical to the one already available in the literature. For a cable made of N equal strands we give a closed form solution that to our knowledge was never presented before. We finally validate the analytical solution by comparison to numerical results in the case of a step-like spatial distribution of the magnetic field over a short Rutherford cable, both in transient and steady state conditions

Acenaphthenoannulation Induced by the Dual Lewis Acidity of Alumina

We have discovered a dual (i. e., soft and hard) Lewis acidity of alumina that enables rapid one-pot π-extension through the activation of terminal alkynes followed by C−F activation. The tandem reaction introduces an acenaphthene fragment – an essential moiety of geodesic polyarenes. This reaction provides quick access to elusive non-alternant polyarenes such as π-extended buckybowls and helicenes through three-point annulation of the 1-(2-ethynyl-6-fluorophenyl)naphthalene moiety. The versatility of the developed method was demonstrated by the synthesis of unprecedented structural fragments of elusive geodesic graphene nanoribbons

TA INSTRUMENTS EQUIPMENT FOR FATIGUE TESTING OF STENTS AND IMPLANTS FOR CARDIOVASCULAR SYSTEM

В данной статье рассмотрены устройство и применение испытательных машин ElectroForce компании TA Instruments (США), для проведения широкого диапазона статических и многоцикловых испытаний и изучения физико-механических свойств материалов и готовых изделий. Особое внимание уделено применению систем ElectroForce для усталостных испытаний трансплантатов органов сердечно-сосудистой системы.Construction and application of ElectroForce test systems (TA Instruments, USA) for wide range of static and cycling tests and physical mechanical properties study of materials and complete products are described in this review. The focus attention is given to application of ElectroForce systems for long cycling testing of cardiovascular implants

Обоснование количества форсунок универсального вентиляторного опрыскивателя

The authors noted the disadvantages of fan sprayers such as OVH-600 and VP-1, associated with uneven application of pesticides due to the oscillatory motion of the working parts, especially in the junction of adjacent passages. (Research purpose) To increase the uniformity of the pesticide solution application over the entire width of the fan sprayer. (Materials and methods) The JV «Agriхim» developed a universal fan sprayer designed for the treatment of field crops, orchards and vineyards controlled by air-droplet flow. It was shown that the number of nozzles depends on the technological scheme of operation and the width of the sprayer. (Results and discussion) The authors determined the optimal number of injectors – 25 pieces. Depending on the flow rate of the working solution, three groups of tips were distinguished. (Conclusions) The authors revealed that the new design eliminates oscillatory movements of the working parts of the sprayer, a significant width (24 meters vs. 16 meters in production models) allows to increase dramatically the productivity of work, and the number of changeovers is minimized. They simplified and cheapened the design of the sprayer due to the rejection of a number of kinematic pairs and drives. They increased reliability of the unit, eliminating rubbing and moving parts and components. They presented the layout of 25 nozzles for high-quality pesticide treatment: 5 rear central nozzles were installed on the air ducts at an angle relative to the soil surface, and on the opposite direction of the air ducts placed 3 and 7 nozzles in each side of the axis of symmetry of the sprayer. It was calculated that the rate of flow of the working fluid in the range of 100-500 liters per hectare can be adjusted by changing the pressure in the system from 2 to 8 bar and the working speed from 3 to 7 kilometers per hour.Отметили недостатки вентиляторных опрыскивателей типа ОВХ-600 и ВП-1, связанные с неравномерностью внесения жидких средств химизации из-за колебательного движения рабочих органов. (Цель исследования) Повысить равномерность внесения раствора жидких средств химизации по всей ширине захвата вентиляторного опрыскивателя. (Материалы и методы) В СП «Agriхim» разработали универсальный вентиляторный опрыскиватель, предназначенный для обработки полевых культур, садов и виноградников управляемым воздушно-капельным потоком. Показали, что количество форсунок зависит от технологической схемы работы и ширины захвата опрыскивателя. (Результаты и обсуждение) Основными рабочими элементами универсального вентиляторного опрыскивателя, дозирующими норму внесения пестицидов, служат распыливающие наконечники, количество которых во многом зависит от технологической схемы работы и ширины захвата опрыскивателя. Определили оптимальное число форсунок – 25 штук. В зависимости от расхода рабочего раствора выделили три группы наконечников. (Выводы) Выявили, что в новой конструкции исключены колебательные движения рабочих органов опрыскивателя, значительная ширина захвата (24 метра против 16 метров в серийных моделях) позволяет резко повысить производительность работ, а число переналадок сведено к минимуму. Упростили и удешевили конструкцию опрыскивателя вследствие отказа от ряда кинематических пар и приводов. Повысили надежность агрегата, исключив трущиеся и движущиеся детали и узлы. Представили схему расположения 25 форсунок для качественной обработки пестицидами: 5 задних центральных установили на воздуховодах под углом относительно поверхности почвы, а на противоположно направленных воздуховодах разместили по 3 и 7 штук в каждой стороне от оси симметрии опрыскивателя. Рассчитали, что норму расхода рабочей жидкости в пределах 100-500 литров на гектар можно регулировать путем изменения давления в системе от 2 до 8 бар и рабочей скорости от 3 до 7 километров в час

Extracorporeal ultrasound exposure by the low-frequency acoustic amplitude-modulated signal on a ureteral stent for preventing its incrustation: experimental determination of optimal application points

Introduction. Incrustation and biofilms formation on the surface of ureteral stents are still the most significant complications of internal drainage of the upper urinary tract. There are much researchers conducted to combat these complications. The lack of a solution to this problem affects the ultimate results of treatment and economic losses. The issue of impact by physical methods on the ureteral stent, particularly the use of extracorporeal ultrasound acoustic exposure remains, promising and poorly covered.Purpose of the study. To determine the optimal application points of extracorporeal acoustic exposure by the low-frequency ultrasonic amplitude-modulated signal on a ureteral stent in an experiment.Materials and methods. The original device was designed. The main principle of its operation is the generation of an amplitude-modulated ultrasonic signal in two modes: pulsed and permanent. A sexually mature mongrel dog was an experimental animal. The ureteral stent was placed by laparotomy and cystotomy. Intraoperatively, the emitter of the developed device was applied to the skin of the animal, according to the previously indicated topographic and anatomical landmarks. At the same time, an ultrasonic wave noise analyzer was applied through the laparotomy wound to the appropriate level of the ureter. Measurements of ultrasound intensity indicators were performed three times in two operating modes of the device.Results. Pulsed mode: for the ureteral upper third, the highest ultrasonic intensity (123.67 dB) was achieved along the posterior axillary line. For the ureteral middle third, the best ultrasound intensity (115 dB) was obtained by the posterior axillary line. For the ureteral lower third, the highest ultrasound intensity (113.67 dB) was noted along the middle axillary line.Permanent mode: the best ultrasonic intensity in the projection of the ureteral upper, middle, and lower thirds was achieved along the posterior axillary line and was 118.67 dB, 117 dB and 116.67 dB, accordingly. However, there was an excessive heat effect, manifested by hyperemia and hyperthermia of the animal's skin, fascicular muscle contractions during the instrument functioned in the permanent mode, which can potentially lead to thermal burns and intolerance to the procedure.Conclusion. The pulsed mode of the device function is most safe. The optimal application points of the instrument emitter for the ureteral upper and middle thirds is the posterior axillary line, and for the ureteral lower third is the middle axillary line

Внедрение газокомпрессорной станции в систему утилизации попутного нефтяного газа

В процессе работы был рассмотрен максимально эффективный метод утилизации попутного нефтяного газа для данного месторождения, который позволяет утилизировать 95% попутного нефтяного газа.In the course of the work, the most efficient method of utilization of associated petroleum gas for this field was considered, which allows utilizing 95% of associated petroleum gas

Optical second harmonic generation in Yttrium Aluminum Borate single crystals (theoretical simulation and experiment)

Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principles calculation of the linear and nonlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potential linear augmented plane wave (FP-LAPW) method. Our calculations show a large anisotropy of the linear and nonlinear optical susceptibilities. The observed dependences of the second order susceptibilities for the static frequency limit and for the frequency may be a consequence of different contribution of electron-phonon interactions. The imaginary parts of the second order SHG susceptibility chi_{123}^{(2)}(omega), chi_{112}^{(2)}(omega), chi_{222}^{(2)}(omega), and chi_{213}^{(2)}(omega) are evaluated. We find that the 2(omega) inter-band and intra-band contributions to the real and imaginary parts of chi_{ijk}^{(2)}\l(omega) show opposite signs. The calculated second order susceptibilities are in reasonably good agreement with the experimental measurements.Comment: 16 pages, 11 figure

Оценка соответствия колеи трактора с междурядьем посевов сельскохозяйственных культур

Various factors can exert detrimental effects on crop growth and development, among which the influence of the machinery's running gear within the machine-tractor unit stands out, particularly within the soil vicinity encompassing the plant's root system. As a result, the area of soil compaction arising from tractor wheel pressure increasingly covers the plant's protective zone. This poses challenges for both root system growth and development, as well as the optimal uptake of soil nutrients, often leads to plant damage or even trampling. Presently, there is no universally accepted metric for assessing the compatibility between tractor track width and the specific inter-row spacing under cultivation. (Research purpose) Development of an indicator to assess the compatibility of the tractor track width with the cultivated inter-row spacing.  (Materials and methods) The analysis demonstrates that the level of compatibility of the tractor track to the crop inter-row spacing is determined based on the dimensions of the crop spacing, the tractor track width, the protective zone outlined by agrotechnical standards, the deviation of the wheel trajectory from the axis of row symmetry, and tire size. (Results and discussion) An analytical correlation has been derived to determine the level of compatibility between tractor track width and crop inter-row spacing, using the context of cotton cultivation as an illustrative example. It has been revealed that among the serial tractors utilized within cotton farms across the region, full-fledged operational performance is exclusively achieved when row spacings measure 60 and 90 centimeters.  In contrast, the utilization of this machinery on row spacings of 70 and 76 centimeters leads to detrimental outcomes such as row trampling and plant damage. (Conclusions) The viability of the developed indicator has been determined and validated. The improvement of the tractor propulsion system should be aimed at devising a technical solution that facilitates seamless adjustment of track width over a broad spectrum, thus allowing for adaptability to diverse row spacing requirements.К факторам, отрицательно влияющим на рост и развитие сельскохозяйственных культур, относится воздействие ходовой части машинно-тракторного агрегата на почву в зоне расположения корневой системы растения. В результате область уплотнения почвы колесами трактора все больше охватывает защитную зону растения. Это затрудняет рост и развитие корневой системы, освоение питательных элементов почвы, приводит к повреждению или вытаптыванию растений. В настоящее время отсутствует единый показатель соответствия колеи трактора и обрабатываемого междурядья. (Цель исследования) Разработка показателя для оценки соответствия колеи трактора с обрабатываемым междурядьем. (Материалы и методы) Показали, что степень соответствия колеи трактора с междурядьем посевов определяется на основе размеров междурядья посевов, колеи трактора, защитной зоны, предусмотренной агротехническими требованиями, отклонением траектории движения колес от оси симметрии междурядья и типоразмеров шин. (Результаты и обсуждение) Выведена аналитическая зависимость, определяющая степень соответствия колеи трактора с междурядьем посевов сельскохозяйственных культур на примере возделывания хлопка. Установили, что имеющиеся в хлопкосеющих хозяйствах республики серийные тракторы обеспечивают полноценную работу только на междурядьях 60 и 90 сантиметров. Применение этих технических средств на междурядьях 70 и 76 сантиметров приводит к вытаптыванию и повреждению рядков растений. (Выводы) Определили и подтвердили приемлемость разработанного показателя. Совершенствование ходовой системы трактора должно быть направлено на поиск технического решения, обеспечивающего изменение колеи трактора бесступенчатым регулированием в широком диапазоне, тем самым адаптирующего ее к любым междурядьям