Simulation of the Betatron Magnetic Field at the Electron Beam Displacement in Comsol Multiphysics

This article describes the betatron magnetic field simulation in Comsol Multiphysics software package. The model makes it possible to evaluate the betatron focusing properties at the moment of electron displacement onto the target. The simulation results coincide with the experiment described earlier. The study shows the vertical size of the target affects the focal spot size. However, a target size decrease leads to low output dose, since not all electrons reach it. Therefore, the vertical size of the target should be greater than or equal to the vertical dimension of the accelerated beam

Investigation of non-oxidative methane conversion over granulated Mo/ZSM-5 catalysts

The relevance of the investigation is caused by the need for rational use of natural hydrocarbon gases, containing methane as the main component. Currently, plenty of these gases are burned in flares at oil production sites, that does great damage to the environment in the oil-producing regions of our country. The most promising process that allows obtaining valuable chemical products is the non-oxidative methane conversion into aromatic hydrocarbons over zeolite catalysts modified with transition metal ions. The Mo/ZSM-5 catalysts have high activity in this process. These catalysts are obtained both by impregnation and solid-phase synthesis. Development of the method of preparation of Mo/ZSM-5 catalysts using binder is of great importance for the industrial technology of processing gaseous hydrocarbons. The aim of the work is to study the effect of concentration and method of introducing a binder on physicochemical and catalytic properties of the Mo/ZSM-5 catalyst in non-oxidative methane conversion. Methods of investigation: IR spectroscopy, low-temperature adsorption of nitrogen, temperature-programmed desorption of ammonia (TPD-NH3), gas chromatography. Results. The Mo-containing catalyst based on ZSM-5 zeolite and nanosized molybdenum powder was prepared via solid-phase synthesis. The authors have studied the effect of a binder on physicochemical properties and activity of the Mo/ZSM-5 catalyst in non-oxidative conversion of methane into aromatic hydrocarbons. It was ascertained that the addition of a binder to the Mo/ZSM-5 catalyst results in a change in its texture and acid characteristics. It is shown that the activity of the Mo-containing zeolite during the non-oxidative conversion of methane into aromatic hydrocarbons is determined by the concentration of the binder in the catalyst and does not depend on the method of its introduction

Investigation of non-oxidative methane conversion over granulated Mo/ZSM-5 catalysts

Актуальность работы обусловлена необходимостью рационального использования природных углеводородных газов, основным компонентом которых является метан и которые в настоящее время в большом количестве сжигаются в факельных установках нефтепромыслов. Наиболее перспективным процессом, позволяющим получать из них ценные химические продукты, является неокислительная конверсия метана в ароматические углеводороды на цеолитных катализаторах, модифицированных ионами переходных металлов. Наибольшую активность в этом процессе проявляют Mo/ZSM-5 катализаторы, которые получают как методом пропитки, так и твердофазным синтезом. Разработка научных основ приготовления Мо/ZSM-5 катализаторов с использованием связующего вещества различной природы имеет большое значение для промышленного внедрения технологии переработки газообразных углеводородов. Цель работы: исследование влияния концентрации и способа введения связующего вещества на физико-химические и каталитические свойства Mo/ZSM-5 катализатора в процессе неокислительной конверсии метана. Методы исследования: ИК-спектроскопия, низкотемпературная адсорбция азота, температурно-программированная десорбция аммиака (ТПД-NH3), газовая хроматография. Результаты. Методом твердофазного синтеза получен Mo-содержащий катализатор на основе цеолита структурного типа ZSM-5 и наноразмерного порошка молибдена. Проведено исследование влияния связующего вещества на физико-химические свойства и активность Mo/ZSM-5 катализатора в процессе неокислительной конверсии метана в ароматические углеводороды. Установлено, что добавка связующего вещества к катализатору Mo/ZSM-5 приводит к изменению его текстурных и кислотных характеристик. Показано, что активность Mo-содержащего цеолита в процессе неокислительной конверсии метана в ароматические углеводороды определяется концентрацией связующего вещества в катализаторе и не зависит от способа его введения.The relevance of the investigation is caused by the need for rational use of natural hydrocarbon gases, containing methane as the main component. Currently, plenty of these gases are burned in flares at oil production sites, that does great damage to the environment in the oil-producing regions of our country. The most promising process that allows obtaining valuable chemical products is the non-oxidative methane conversion into aromatic hydrocarbons over zeolite catalysts modified with transition metal ions. The Mo/ZSM-5 catalysts have high activity in this process. These catalysts are obtained both by impregnation and solid-phase synthesis. Development of the method of preparation of Mo/ZSM-5 catalysts using binder is of great importance for the industrial technology of processing gaseous hydrocarbons. The aim of the work is to study the effect of concentration and method of introducing a binder on physicochemical and catalytic properties of the Mo/ZSM-5 catalyst in non-oxidative methane conversion. Methods of investigation: IR spectroscopy, low-temperature adsorption of nitrogen, temperature-programmed desorption of ammonia (TPD-NH3), gas chromatography. Results. The Mo-containing catalyst based on ZSM-5 zeolite and nanosized molybdenum powder was prepared via solid-phase synthesis. The authors have studied the effect of a binder on physicochemical properties and activity of the Mo/ZSM-5 catalyst in non-oxidative conversion of methane into aromatic hydrocarbons. It was ascertained that the addition of a binder to the Mo/ZSM-5 catalyst results in a change in its texture and acid characteristics. It is shown that the activity of the Mo-containing zeolite during the non-oxidative conversion of methane into aromatic hydrocarbons is determined by the concentration of the binder in the catalyst and does not depend on the method of its introduction

An accelerator facility for WDM, HEDP, and HIF investigations in Nazarbayev University

Nazarbayev University (NU) in Astana, Kazakhstan, is planning to build a new multi-MV, ~10 to several hundred GW/cm2 ion accelerator facility which will be used in studies of material properties at extreme conditions relevant to ion-beam-driven inertial fusion energy, and other applications. Two design options have been considered. The first option is a 1.2 MV induction linac similar to the NDCX-II at LBNL, but with modifications, capable of heating a 1 mm spot size thin targets to a few eV temperature. The second option is a 2 - 3 MV, ~200 kA, single-gap-diode proton accelerator powered by an inductive voltage adder. The high current proton beam can be focused to ~1 cm spot size to obtain power densities of several hundred GW/cm2, capable of heating thick targets to temperatures of tens of eV. In both cases, a common requirement to achieving high beam intensity on target and pulse length compression is to utilize beam neutralization at the final stage of beam focusing. Initial experiments on pulsed ion beam neutralization have been carried out on a 0.3 MV, 1.5 GW single-gap ion accelerator at Tomsk Polytechnic University with the goal of creating a plasma region in front of a target at densities exceeding ~1012 cm-3