538 research outputs found

    Electron cyclotron resonance near the axis of the gas-dynamic trap

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    Propagation of an extraordinary electromagnetic wave in the vicinity of electron cyclotron resonance surface in an open linear trap is studied analytically, taking into account inhomogeneity of the magnetic field in paraxial approximation. Ray trajectories are derived from a reduced dispersion equation that makes it possible to avoid the difficulty associated with a transition from large propagation angles to the case of strictly longitudinal propagation. Our approach is based on the theory, originally developed by the Zvonkov and Timofeev [1], who used the paraxial approximation for the magnetic field strength, but did not consider the slope of the magnetic field lines, which led to considerable error, as has been recently noted by Gospodchikov and Smolyakova [2]. We have found ray trajectories in analytic form and demonstrated that the inhomogeneity of both the magnetic field strength and the field direction can qualitatively change the picture of wave propagation and significantly affect the efficiency of electron cyclotron heating of a plasma in a linear magnetic trap. Analysis of the ray trajectories has revealed a criterion for the resonance point on the axis of the trap to be an attractor for the ray trajectories. It is also shown that a family of ray trajectories can still reach the resonance point on the axis if the latter generally repels the ray trajectories. As an example, results of general theory are applied to the electron cyclotron resonance heating experiment which is under preparation on the Gas Dynamic Trap in the Budker Institute of Nuclear Physics [3]

    Synthesis and Hydrothermal Study of (Na,K)M2(PO4)3 (M = Ti, Zr, Hf) Solid Solutions

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    (Na,K)M2(PO4)3 (M = Ti, Zr, Hf) continuous solid solutions were synthesized by sol-gel and solidstate methods. Cation-exchange reactions in the NaM2(PO4)3–KM2(PO4)3–NaCl–KCl–H2O systems were studied at T = 723 – 973 K and p = 100–200 MPa. The concentration dependences of unit cell parameters of the studied phosphates were found. The sodium/potassium distribution coefficients in the phosphate-fluid systems were functions of the solid solution compositions, that is, the systems behave nonideally. The excess volumes and excess Gibbs functions of solid solutions mixing were fitted to thirdorder polynomials and described in terms of the Margules model. From the comparison of the results obtained Ti-, Zr-, and Hf-systems, we made the conclusion that the titanium phosphates show greater nonideality than zirconium and hafnium phosphates and lower thermodynamic stability to decomposition to double phosphates at high pressures and temperatures

    ВПЛИВ РІЗНИХ СИСТЕМ ОСНОВНОГО ОБРОБІТКУ ҐРУНТУ ТА УДОБРЕННЯ НА ВРОЖАЙНІСТЬ ЗЕРНА КУКУРУДЗИ В ЗРОШУВАНИХ УМОВАХ ПІВДНЯ УКРАЇНИ

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    The article presents the results of the research on soil bulk density and permeability as well as weediness of maize crops at the beginning and end of growing season on average for 2016-2019, applying different basic tillage and fertilizer systems. The goal of the research was to determine the effect of different methods and depth of basic tillage and fertilizers on agrophysical properties of soil and crop productivity in grain-row crop rotation when irrigating in the south of Ukraine. The objective of the research was to determine the effects of different methods and depths of basic tillage as well as fertilization on the agrophysical properties of dark chestnut soil and the productivity of corn in short crop rotation. During the experiment, field, quantitative-weight, visual, laboratory, calculation-comparative, mathematical-statistical methods and generally accepted in Ukraine methods and methodical recommendations were used. The research was conducted in the research fields of the Askanian SARS IIA NAAS of Ukraine. Based on the research results it was established that, both at the beginning and at the end of grooving season when applying the tillage up to 28-30 cm within the system of differentiated tillage bulk density was the smallest as 1,14 g/cm3 when using green manure and 1,19 g/cm3 without its use. When applying subsurface different depth tillage, bulk density increased up to 1,18 g/cm3 when using green manure and up to 1,26 g/cm3 without its use. Maximum bulk density of 1,28 g/cm3 was observed when no tillage applied without using green manure and 1,31 g/cm3 when using it that is by 12,3 and 10.1% higher compared to the reference area, respectively. The highest corn productivity was observed when applying subsurface different depth tillage, where the average values by the factor A were about 10,93 t/ha that is higher than those obtained in the reference area by 0,52 t/ha, or 5,0%. The use of zero tillage caused the obtaining of the lowest yield in the experiment as 8,71 t/ha that is less compared to the reference area by 1,7 t/ha, or 19,5%.У статті відображено результати досліджень щільності складення, водопроникності та забур’яненості посівів кукурудзи в середньому за 2016-2019 рр. за різних систем основного обробітку ґрунту та удобрення. Метою досліджень було визначення впливу різних способів та глибини основного обробітку ґрунту в сівозміні та удобрення на агрофізичні властивості ґрунту та продуктивність кукурудзи в зерно-просапній сівозміни на зрошенні півдня України. Завдання дослідження полягало у визначенні впливу різних способів і глибини основного обробітку та удобрення на агрофізичні властивості темно-каштанового ґрунту та продуктивність кукурудзи в короткоротаційній сівозміні. Під час експерименту використовували польовий, кількісно-ваговий, візуальний, лабораторний, розрахунково-порівняльний, математично-статистичний методи та загальновизнані в Україні методики і методичні рекомендації. Дослідження проводили на дослідних полях Асканійської ДСДС ІЗЗ НААН України. В результаті досліджень встановлено, що, як на початку, так і в кінці вегетації за оранки на 28-30 см, у системі диференційованого обробітку показники щільності складення були найменшими та становили 1,14 г/см3 на фоні сидерації та 1,19 г/см3 без її використання, за системи безполицевого різноглибинного розпушування показники щільності складення зросли до 1,18 г/см3 на фоні сидерату та 1,26 г/см3 без його використання. Максимальні ж показники щільності складення 1,28 г/см3 спостерігались за нульового обробітку ґрунту в сівозміні   без сидератів та 1,31 г/см3 з його використанням, що відповідно на 12,3 та на 10,1% вище порівняно з контролем. Найвищий  рівень продуктивності кукурудзи відзначився за безполицевого різноглибинного обробітку, де показники в середньому по фактору А складали 10,93 т/га, що більше контролю на 0,52 т/га, або 5,0%, а застосування нульового обробітку призвело до найменших показників в досліді 8,71 т/га, що менше порівняно з контролем на 1,7 т/га, або 19,5%

    A Quench Detection and Monitoring System for Superconducting Magnets at Fermilab

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    A quench detection system was developed for protecting and monitoring the superconducting solenoids for the Muon-to-Electron Conversion Experiment (Mu2e) at Fermilab. The quench system was designed for a high level of dependability and long-term continuous operation. It is based on three tiers: Tier-I, FPGA-based Digital Quench Detection (DQD); Tier-II, Analog Quench Detection (AQD); and Tier-3, the quench controls and data management system. The Tier-I and Tier-II are completely independent and fully redundant systems. The Tier-3 system is based on National Instruments (NI) C-RIO and provides the user interface for quench controls and data management. It is independent from Tiers I & II. The DQD provides both quench detection and quench characterization (monitoring) capability. Both DQD and AQD have built-in high voltage isolation and user programmable gains and attenuations. The DQD and AQD also includes user configured current dependent thresholding and validation times. A 1st article of the three-tier system was fully implemented on the new Fermilab magnet test stand for the HL-LHC Accelerator Up-grade Project (AUP). It successfully provided quench protection and monitoring (QPM) for a cold superconducting bus test in November 2020. The Mu2e quench detection design has since been implemented for production testing of the AUP magnets. A detailed description of the system along with results from the AUP superconducting bus test will be presented

    Гемодинамический статус пациентов с различными вариантами коморбидности ишемической болезни сердца до и после коронарного шунтирования

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    Aim. To assess the hemodynamic status by transpulmonary thermodilution (TPTD) in patients with ischemic heart disease (IHD) with different comorbidities before and after coronary artery bypass grafting (CABG).Materials and methods. 66 patients with IHD (40 men and 26 women) aged 53 to 77 years who were admitted for planned CABG were examined. The patients were divided into three groups according to the comorbidity: cardiovascular, respiratory, and metabolic. The first comorbidity was represented by a combination of IHD and multifocal atherosclerosis, the second – by IHD and chronic obstructive pulmonary disease (COPD), and the third – by IHD and metabolic syndrome (MS). All patients underwent CABG with the use of cardiopulmonary bypass. Hemodynamic parameters were recorded by the TPTD method using the Pulsion Picco Plus module (Germany) at 3 stages: after the start of mechanical ventilation (stage I), after the completion of cardiopulmonary bypass (stage II), and 24 hours after CABG (stage III).Results. The patients with IHD with different comorbidities differed in characteristic signs of hemodynamic changes. In IHD with comorbid COPD, after withdrawal from the cardiopulmonary bypass and 24 hours after CABG, the highest index of systemic vascular resistance, the minimum values of the global ejection fraction, and a decrease in the global end-diastolic volume and pulmonary blood volume less noticeable compared with other groups of patients were noted. With comorbid respiratory and metabolic disorders, the maximum values for the indices of extravascular lung water and pulmonary vascular permeability were recorded. In the patients with a comorbid cardiovascular disease, hemodynamic and volume status violations in the dynamic follow-up were less pronounced.Conclusion. The use of the TPTD method in patients with IHD before and after CABG makes it possible to specify the functional state of the circulatory system in different comorbidities, which increases the effectiveness of risk stratification and the accuracy of predicting possible complications.Цель – оценить гемодинамический статус методом транспульмональной термодилюции (ТПТД) у больных ишемической болезнью сердца (ИБС) с различными вариантами коморбидности до и после коронарного шунтирования (КШ).Материалы и методы. Обследованы 66 больных ИБС (40 мужчин и 26 женщин) в возрасте 53–77 лет, поступивших на плановое КШ, которые были разделены на три группы коморбидности: кардиоваскулярную, респираторную и метаболическую. Первая из них представлена сочетанием ИБС и мультифокального атеросклероза, вторая – ИБС и хронической обструктивной болезни легких (ХОБЛ), третья – ИБС и метаболического синдрома (МС). Всем больным проведено КШ в условиях искусственного кровообращения (ИК). Показатели гемодинамики регистрировали методом ТПТД с использованием модуля Pulsion Picco Plus (Германия) на трех этапах: после начала искусственной вентиляции легких (I этап), после завершения ИК (II этап) и через 24 ч после КШ (III этап).Результаты. Больные ИБС с различными вариантами коморбидности отличались характерными признаками гемодинамических изменений. При сочетании ХОБЛ и ИБС после отхода от ИК и через 24 ч после КШ отмечен наиболее высокий индекс системного сосудистого сопротивления, минимальные значения глобальной фракции изгнания, менее заметное по отношению к другим группам больных снижение глобального конечного диастолического объема и легочного объема крови. При респираторной и метаболической коморбидности фиксировались максимальные значения индексов внесосудистой жидкости в легких и проницаемости легочных сосудов. У больных с кардиоваскулярной коморбидностью нарушения гемодинамического и волемического статуса в динамике наблюдения были менее выраженными.Заключение. Использование метода ТПТД у больных ИБС до и после КШ позволяет детализировать функциональный статус системы кровообращения при различных вариантах коморбидности, что повышает эффективность риск-стратификации и точность прогнозирования возможных осложнений

    The H1 Forward Proton Spectrometer at HERA

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    The forward proton spectrometer is part of the H1 detector at the HERA collider. Protons with energies above 500 GeV and polar angles below 1 mrad can be detected by this spectrometer. The main detector components are scintillating fiber detectors read out by position-sensitive photo-multipliers. These detectors are housed in so-called Roman Pots which allow them to be moved close to the circulating proton beam. Four Roman Pot stations are located at distances between 60 m and 90 m from the interaction point.Comment: 20 pages, 10 figures, submitted to Nucl.Instr.and Method
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