New Approach to Study the Ignition Processes of Organic Coal-Water Fuels in an Oxidizer Flow

To converge the conditions of organic water-coal fuel composition combustion in the typical power equipment we developed a new approach and installed an experimental setup, eliminating the traditional fixing the fuel droplets on the thermocouples or rods. Specialized cone-shaped chamber was used to implement the process of lingering of organic water-coal fuel droplets. Necessary and sufficient conditions for the lingering of organic water-coal fuel droplets were established. We determined the parameters of the system (droplet size of 0.4-0.6 mm, temperatures 823-903 K and the velocity of the oxidizer flow 1.5-6 m/s) at which the droplets were consistently ignited in the process of lingering. Minimum temperatures and ignition delay times of organic water-coal fuel droplets based on brown coal, used motor, turbine, transformer oils, kerosene, gasoline and water were defined

Low-temperature phase separation of a binary liquid mixture in porous materials studied by cryoporometry and pulsed-field-gradient NMR

The low-temperature liquid-liquid phase separation of the partially miscible hexane-nitrobenzene mixture imbibed in porous glasses of different pore sizes from 7 to 130 nm has been studied using 1H NMR (nuclear magnetic resonance) cryoporometry and pulse field gradient NMR methods. The mixture was quenched below both its upper critical solution temperature (T cr) and the freezing point of nitrobenzene. The size distribution of frozen nitrobenzene domains was derived through their melting point suppression according to the Gibbs-Thompson relation. The obtained data reveal small initial droplets of nitrobenzene surrounded by hexane, which are created as the temperature is decreased below Tcr and which thereafter coalesce by a droplet-diffusion mechanism. The inter-relation between the pore size and the found size distribution and shapes of nitrobenzene domains is discussed, as well as several aspects of molecular self-diffusion. © 2002 The American Physical Society

Short-time diffusion behavior of Brownian particles in porous solids

© Kazan Federal University (KFU). The process of self-diffusion of particles confined to porous solids is studied for time intervals corresponding to particle displacements shorter than the characteristic pore size. The solid matrix is modeled as a (random) potential field with an infinitely large potential within the solid which decays to zero at distances of the order of a few particle sizes from the pore walls. Diffusion of particles in the thus created potential field is described by the Smoluchowski diffusion equation. It is shown that, for short diffusion times, the resulting equation for the time-depended diffusivity reproduces that earlier obtained in the literature [Mitra et al., Phys. Rev. Lett. 68, 3555 (1992)], but with the numerical constant differing by factor 2. The conditions under which this discrepancy arises are highlighted and discussed

Guia de museus como meio de envolvimento de crianças em idade escolar primária no patrimônio histórico e cultural

The purpose of the work was to study the cognitive interest of primary school-aged children in the historical and cultural heritage, in order to create children's guide-book to the Museum-reserve “Kazan Kremlin”, located in the Republic of Tatarstan, Kazan, Russia.Theoretical and empirical research methods were used to solve the assigned tasks. The analysis of pedagogical and museological literature was performed. Questionnaire survey and interviewing were carried out, followed by mathematical analysis of the sample.The experience of museum pedagogy was used as a theoretical method. In the course of its studying it was revealed, that younger schoolchildren were attracted by external effects and practical orientation of excursions. And the most effective way was the creation of game situation, in which the child was stimulated to make individual discovery.The study was based on a specially developed questionnaire for children of primary school age, for their parents and museum workers of the complex “Kazan Kremlin”.Based on the results of collected data, the guide-book was developed. It includes learning games, which contain historical, art and religious information, adapted to the group of children 7-10 years old.El propósito del trabajo fue estudiar el interés cognitivo de los niños en edad escolar primaria en el patrimonio histórico y cultural, con el fin de crear una guía para niños de la reserva del museo "Kazan Kremlin", ubicado en la República de Tatarstán, Kazán, RusiaSe usaron métodos de investigación teóricos y empíricos para resolver las tareas asignadas. Se realizó el análisis de la literatura pedagógica y museológica. Se llevaron a cabo cuestionarios y entrevistas, seguidos de un análisis matemático de la muestra.La experiencia de la pedagogía museística se utilizó como método teórico. En el curso de su estudio se reveló que los escolares más pequeños se sentían atraídos por los efectos externos y la orientación práctica de las excursiones. Y la forma más efectiva fue la creación de la situación del juego, en la que el niño fue estimulado para hacer un descubrimiento individual.El estudio se basó en un cuestionario especialmente desarrollado para niños de edad escolar primaria, para sus padres y trabajadores de museos del complejo "Kazan Kremlin".Con base en los resultados de los datos recopilados, se desarrolló la guía. Incluye juegos de aprendizaje, que contienen información histórica, artística y religiosa, adaptada al grupo de niños de 7-10 añosO objetivo deste trabalho foi estudar o interesse cognitivo das crianças em idade escolar primária do património histórico e cultural, a fim de criar um guia para reserva crianças museu "Kazan Kremlin", localizada na República de Tatarstan, Kazan . RússiaMétodos de pesquisa teórica e empírica foram utilizados para resolver as tarefas atribuídas. A análise da literatura pedagógica e museológica foi realizada. Questionários e entrevistas foram realizados, seguidos de uma análise matemática da amostra.A experiência da pedagogia do museu foi usada como método teórico. No curso de seu estudo, revelou-se que as crianças mais jovens eram atraídas pelos efeitos externos e pela orientação prática das excursões. E a maneira mais eficaz foi a criação da situação do jogo, em que a criança foi estimulada a fazer uma descoberta individual.O estudo foi baseado em um questionário especialmente desenvolvido para crianças em idade escolar primária, para seus pais e trabalhadores de museus do complexo "Kazan Kremlin".Com base nos resultados dos dados coletados, o guia foi desenvolvido. Inclui jogos de aprendizagem, que contêm informações históricas, artísticas e religiosas, adaptadas ao grupo de crianças de 7 a 10 anos

Time dependent self-diffusion coefficient of molecules in porous media

Using Monte Carlo simulation, the time dependence of the self-diffusion coefficient D(t) in porous media was investigated. It was found to be a decaying function with a cut-off to zero at time t. The exact form of decay depended on the details of the geometry of porous space. The details of the geometry were described by the surface orientation autocorrelation function. The short-term behavior of D(t) was governed by the surface population of the molecules

Lévy walks of strong adsorbates on surfaces: Computer simulation and spin-lattice relaxation

Using a Monte Carlo method, the time dependence of the mean-squared displacements along planar and spherical liquid-solid interfaces and the displacement distribution were simulated for a random walker. In the strong-adsorption-short-displacement limit, the Cauchy propagator typical for Lévy walks was verified. It is shown that the displacements effectively taking place along surfaces follow a superdiffusive time dependence of the mean square. Surface diffusion is the crucial process of the "reorientations mediated by translational displacements" mechanism of spin-lattice relaxation. This is demonstrated by considering a strongly adsorbed molecule population on spherical surfaces or on planar surface patches representing a certain finite orientation correlation length. The conclusion is that Lévy walks on curved surfaces account for the experimental findings obtained with field-cycling NMR relaxometry, whereas strongly adsorbed molecules escaping to the bulk liquid play a minor role

Spectral variations of AeBe Herbig stars in the Mon R1 association

We present the change in the Halpha emission-line profile of the spectra of some AeBe Herbig stars. In the spectrum of VY Mon, Halpha may have one of three profile types: P Cyg, P Cyg III or single line in accordance with the brightness variations of the star. HD259431 now shows a double Halpha profile with the red component stronger than the blue component, while in the earlier observations the blue peak was higher than the red peak. Finally, the last Halpha profile of LkHalpha215 is very similar to that obtained by Finkenzeller et al.Comment: 4pages, 3figure

Diffusion in nanopores recorded by microscopic measuring techniques

The poster presents two measuring techniques which, by their very nature, can be focused on, exclusively, microscopic dimensions, including the interior of the individual particles (crystallites) of the material under study. Correspondingly, they are referred to as “microscopic measuring techniques”. The examples presented refer, in particular, to the potentials of these techniques for investigating mass transfer in complex systems

Self-diffusion of water and oil in peanuts investigated by PFG NMR

Pulsed field gradient (PFG) nuclear magnetic resonance (NMR) has been used to study self-diffusion characteristics of water and oil in natural peanuts and in peanuts saturated with water. From the dependence on diffusion time of the echo decay due to diffusion, regions of completely restricted diffusion for the oil molecules were identified. The mean size and size distribution function of these regions were obtained. Combined analysis of diffusion data for peanuts with natural moisture content and for water saturated peanuts shows the cellular nature of these regions. The cell structure, consisting of a cell cavity surrounded by a double membrane was identified

Estimation of energy efficiency of street lighting systems

The paper considers the issue of quantitative estimation of energy efficiency of street lighting systems. A formula is proposed for calculating energy efficiency and comparing various street lighting options by the criterion of energy efficiency.В работе рассмотрен вопрос количественной оценки энергоэффективности систем уличного освещения. Предложена формула для расчета энергоэффективности и сравнения различных вариантов уличного освещения по критерию энергоэффективности