Microstructure and magnetic properties of magnetic fluids consisting of shifted dipole particles under the influence of an external magnetic field

We investigate the structure of a recently proposed magnetic fluid consisting of shifted dipolar (SD) particles in an externally applied magnetic field via computer simulations. For standard dipolar fluids the applied magnetic field usually enhances the dipole-dipole correlations and facilitates chain formation whereas in the present system the effect of an external field can result in a break-up of clusters. We thoroughly investigate the origin of this phenomenon through analyzing first the ground states of the SD-particle systems as a function of an applied field. In a second step we quantify the microstructure of these systems as functions of the shift parameter, the effective interaction parameter, and the applied magnetic field strength. We conclude the paper by showing that with the proper choice of parameters, it is possible to create a system of SD-particles with highly interacting magnetic particles, whose initial susceptibility is below the Langevin susceptibility, and which remains spatially isotropic even in a very strong external magnetic field. © 2013 AIP Publishing LLC

Possibilities for the Widespread Development of Hydrogen in Fuel Systems

Представлен краткий обзор комплексного подхода к освоению водородного топлива в различных топливных системах. Раскрыто понятие оптимальности топливной системы. Показана необходимость формирования общей наземной инфраструктуры по обеспечению водородным топливом наземного и воздушного транспорта с применением композитных баллонов одного типа и уровня давления (до 70 МПа). Аргументирована необходимость охлаждения газообразного водорода, заправляемого в баллон высокого давления. Проведен расчет азотно-водородного теплообменного аппарата по традиционной методике в стационарной постановке. Приведена нестационарная математическая модель теплового состояния теплообменного аппарата. Приведены расчетно-экспериментальные результаты испытаний теплообменного аппарата для охлаждения газообразного водорода жидким азотом. Представлена оценка полученных результатов.This article presents a brief review of the integrated approach to the development of hydrogen fuel in various fuel systems. The authors disclose the notion of optimality of the fuel system and explain the necessity of forming a common ground infrastructure for hydrogen fuel supply of ground and air transport with the use of composite cylinders of the same type and pressure level (up to 70 MPa). Necessity to cool hydrogen gas, which is being pumped into a high-pressure balloon, is shown. Calculation of the nitrogen-hydrogen heat exchanger according to the traditional method in a stationary setting is carried out. A non-stationary mathematical model of the heat state of a heat exchanger is given. Calculation and experimental results of tests of a heat exchanger for cooling hydrogen gas with liquid nitrogen are presented. The estimation of the received results is presented