АНАЛІЗ ПАРАМЕТРІВ ГЕНЕРАТОРА НА ОСНОВІ ЕЛЕКТРОДИНАМІЧНОЇ ХВИЛЕВОДНОЇ СИСТЕМИ

The analysis of the oscillating system with the waveguide expansion in the H-plane is given and its parameters are determined for a six-diode generator with parallel inclusion of diodes in the general electrodynamic system. The spectrum of oscillations of the natural frequencies in the symmetric expansion of the open waveguide type resonator and the conditions for reaching the maximum output power with the addition of several pulsed LPD in the resonator are determined. Their energy and frequency characteristics are investigated. The symmetric expansion of a rectangular waveguide in the - plane is considered as an open resonator of the waveguide type. Rectangular waveguides with hopping in the H-plane are the simplest open resonators and can find practical applications as power adders of active elements in the centimeter and millimeter wavelengths. The scheme of parallel inclusion of semiconductor pulse diodes in such electrodynamic systems is proposed, which allows to increase significantly the packing density of diodes and to improve heat dissipation. The analysis of the spatial distribution of the electric field of the "working" oscillation allowed to obtain valuable information on the location of the field hollows in the locations of semiconductor sources, as well as on the phase portrait of the oscillation field, which determines the way of inclusion of these sources. On the basis of theoretical studies, equations were obtained to calculate the basic parameters of a waveguide power generator of a pulse generator.Приведен анализ колебательной системы со скачкообразным расширением волновода в Н-плоскости и определены её параметры для шестидиодного генератора с параллельным включением диодов в общей электродинамической системе. Определен  спектр  колебаний собственных частот в симметричном  Н расширении открытого резонатора волноводного типа и условий достижения максимальной выходной мощности при сложении нескольких импульсных ЛПД в резонаторе.  Исследованы их энергетические и частотные характеристики. В качестве открытого резонатора волноводного типа рассмотрено симметричное расширение прямоугольного волновода в Н - плоскости. Показано, что прямоугольные волноводы со скачкообразным расширением в Н-плоскости являются наиболее простыми открытыми резонаторами и могут найти практическое применение в качестве сумматоров мощностей активных элементов в сантиметровом и миллиметровом диапазоне длин волн. Предложена схема параллельного включения полупроводниковых импульсных диодов в подобные электродинамические системы, что позволяет существенно увеличить плотность упаковки диодов и улучшить отвод тепла. Анализ пространственного распределения электрического поля «рабочего» колебания позволил получать ценную информацию о расположении пучностей поля, в местах которых помещаются полупроводниковые источники, а также о фазовом портрете поля Н колебания, определяющим способ включения этих источников. На основе теоретических исследований   получены уравнения для расчёта основных параметров волноводного сумматора мощности импульсного генератора.Наведено аналіз  системи, що коливається, з стрибкоподібним  розширенням хвилеводу в Н-плоскості та визначено  параметри для шостидіодного генератора з паралельним включенням діодів у загальнодоступних електродинамічних системах. Визначено спектр колективних власних частот у симетричних розширеннях відкритого резонатора хвилеводного типу та умов  досягнення максимальної вихідної потужності при стилізації декількох імпульсних ЛПД в резонаторі. Досліджено  їх енергетичні та частотні характеристики. У якості відкритого резонатора волноводного типу розглянуто  симетричне розширення прямокутного  хвилеводу в Н- плоскості. Показано, що прямокутні   хвилеводи зі стрибкоподібним  розширенням в Н-плоскості   сумматорів є найбільш простішими відкритими резонаторами та можуть знайти практичне застосування  у якості сумматорів потужностей  активних елементів в сантиметровому і мілліметровому діапазоні   довжин  хвиль. Запропонована схема паралельного включення напівпровідникових імпульсних діодів у подібних електродинамічних системах, що дозволяє значно збільшити плотність упаковки діодів і покращити  відвід тепла. Наведено отриману інформацію про розташування пучків поля, в яких розміщені напівпровідникові джерела, а також про фазові портрети поля колеса, що визначають можливість включення цих джерел На основі теоретичних досліджень отримані порівняння для розрахунку  основних параметрів хвилеводного сумматора потужності імпульсного генератора

The Complete Flux Scheme : error analysis and application to plasma simulation

The Complete Flux scheme (CFS) (J.H.M. ten Thije Boonkkamp et al., J. Sci. Comput. 46 (2011) 47–70) is an extension of the widely used exponential di¿erence scheme for advection-di¿usion-reaction equations. In the present paper we provide a rigorous proof that the convergence order of this scheme is 2 for all grid Péclet numbers, whereas that of the exponential scheme reduces to 1 for high grid Péclet numbers in the presence of source terms. The performance of both schemes is compared in two case studies: a model system and a real-world model of a parallel-plate glow discharge. The results indicate that the usage of CFS allows a considerable reduction of the number of grid points that is required to obtain the same accuracy. The MATLAB/Octave source code that has been used in these studies has been made available

Raman elastic geobarometry for anisotropic mineral inclusions

Elastic geobarometry for host-inclusion systems can provide new constraints to assess the pressure and temperature conditions attained during metamorphism. Current experimental approaches and theory are developed only for crystals immersed in a hydrostatic stress field, whereas inclusions experience deviatoric stress. We have developed a method to determine the strains in quartz inclusions from Raman spectroscopy using the concept of the phonon-mode Grüneisen tensor. We used ab initio Hartree-Fock/Density Functional Theory to calculate the wavenumbers of the Raman-active modes as a function of different strain conditions. Least-squares fits of the phonon-wavenumber shifts against strains have been used to obtain the components of the mode Grüneisen tensor of quartz (γm1 and γm3) that can be used to calculate the strains in inclusions directly from the measured Raman shifts. The concept is demonstrated with the example of a natural quartz inclusion in eclogitic garnet from Mir kimberlite and has been validated against direct X-ray diffraction measurement of the strains in the same inclusion

Laminar mixing in a SMX static mixer evaluated by positron emission particle tracking (PEPT) and magnetic resonance imaging (MRI)

AbstractStatic mixers are implemented across many industries and are used for mixing, heating and reacting processes. This paper reports the combined use of positron emission particle tracking (PEPT) and magnetic resonance imaging (MRI) to assess mixing in the industrially important SMX static mixer geometry. The focus of this study was distributive mixing for a Newtonian fluid, glycerol, flowing in the laminar regime in the standard SMX static mixer. By implementing PEPT and MRI techniques, the work elucidated mixing indices that incorporate both local velocities and concentration fields within the structure of the mixer element at 0.5mm intervals over a length of nine 1.0L/D SMX elements. The experimental results are placed in context with previously published computational studies for this geometry

Raman elastic geobarometry for anisotropic mineral inclusions

Elastic geobarometry for host-inclusion systems can provide new constraints to assess the pressure and temperature conditions attained during metamorphism. Current experimental approaches and theory are developed only for crystals immersed in a hydrostatic stress field, whereas inclusions experience deviatoric stress. We have developed a method to determine the strains in quartz inclusions from Raman spectroscopy using the concept of the phonon-mode Gr\ufcneisen tensor. We used ab initio Hartree-Fock/Density Functional Theory to calculate the wavenumbers of the Raman-active modes as a function of different strain conditions. Least-squares fits of the phonon-wavenumber shifts against strains have been used to obtain the components of the mode Gr\ufcneisen tensor of quartz (\u2060\u3b3m1 and \u3b3m3\u2060) that can be used to calculate the strains in inclusions directly from the measured Raman shifts. The concept is demonstrated with the example of a natural quartz inclusion in eclogitic garnet from Mir kimberlite and has been validated against direct X-ray diffraction measurement of the strains in the same inclusio

Silver zeolite-loaded silicone elastomers: a multidisciplinary approach to synthesis and antimicrobial assessment

A multidisciplinary approach has been applied to the preparation of antibacterial Ag zeolite/silicone elastomer composites aimed at products that satisfy a range of requirements, namely good mechanical properties after zeolite incorporation and strongly antibacterial. Zeolite X was synthesised and used as antibacterial agent after ion-exchange with silver. The high level of silver (14 wt%) within the zeolite enabled the preparation of antibacterial composites containing a relatively low level of zeolite (2 wt%). The composites showed strong efficacy against Escherichia coli and Staphylococcus epidermidis. Organic functionalization of the zeolite with organo-silanes prior blending with the matrix usefully improved composite mechanical properties and reduced color development in Ag zeolite containing silicone elastomers. Organo-silane modification did not substantially affect the antibacterial performance of the materials; the number of viable cells of both Gram-positive and Gram-negative bacteria was reduced to beyond detection limits within 24 hours of incubation. Efficacy of the Ag zeolite containing composites against the yeast Candida albicans was found to be substantially less than observed with the two bacteria. This study demonstrates that evaluation of polymer composites needs to be performed via a multidisciplinary approach in order to avoid compromising a particular aspect of the materials' design, characteristics or performance, including the use of reliable testing methods to determine the latter

Novel merwinite/akermanite ceramics: in vitro bioactivity

The ceramics in the system CaO – MgO – SiO2 has recently received a great deal of attention because they exhibit good in vitro bioactivity and have potential use as bone implants. Biphasic calcium-magnesium-silicate ceramics was prepared by a sol-gel method. The dried gel with chemical composition 3CaO.MgO.2SiO2 was thermally treated at 1300°C for 2 h. The structural behavior of the synthesized ceramics was examined by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Merwinite, as the main crystalline phase, and akermanite, as the minor phase, were identified. The in vitro bioactivity of the synthesized ceramic samples was recorded in Simulated Body Fluid (SBF) for different times of soaking. The apatite formation on the surface of the immersed samples was detected by FTIR, SEM and Energy Dispersive Spectroscopy (EDS) techniques. The ion concentrations in the SBF solutions after the in vitro test were evaluated by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). On the basis of the results obtained, the ability of the biphasic ceramics to deposit apatite layer was found. The peculiarities of the formation of apatite layer depending on the phase composition were analyzed and discussed

CALCULATION METHODS OF OPTIMIZATION OF RADIATION PROTECTION CONTAINERS FOR STORAGE SOLID RADIOACTIVE WASTE

The report contains an analysis of the effectiveness of the protection from gamma-radiation steel canisters and protected by lead and placed in a container of NZK-I. the course work has been applied to the calculation of Monte Carlo. The results of calculations made recommendations aimed at enhancing the protection and reducing its material consumption.В докладе содержится анализ эффективности защиты от гамма-излучения стальных пеналов с РАО, окруженных свинцовой защитой и помещенных в контейнер НЗК-I. В ходе работы был применен расчет по методу Монте-Карло. По результатам расчетов вынесены рекомендации, направленные на повышение эффективности защиты и уменьшение ее материалоемкости