Optimization of the Cremator Settings for the Disposal of Poultry Waste By Incineration in a Beet-emitting Boiler

The purpose of this work is to substantiate the parameters of the boiler unit, which ensures the cremation of manure using microwave radiation. The substantiation of the amount of heat released during the burning of chicken manure at the industrial keeping of poultry in the conditions of sharply continental climate on the basis of minimization of product utilization values - ash content of wastes and pollution of smoke emissions is presented. Using the obtained regression models of magnetron emission power, moisture content of the burnt manure mass, mass air consumption for the specified product utilization parameters, the analysis of the relationship between the obtained parameters is made. Correlation analysis has shown a high correlation between the amount of heat released during the combustion of manure and the concentration of carbon monoxide in the smoke emissions. Rationally, the value of carbon monoxide content in the flue gases is 3.9%, corresponding to the amount of heat released 2.1 MJ/kg at the combustion of a kilogram of manure at the ash content of the residue of 18.4% and the initial moisture content of the manure of 38.4%. It provides power of radiation of magnetron 400 W on 1 kg of a waste and the mass flow rate of air of 13.8 kg/h

a descriptive study of "Samsung Man" phenomenon

Thesis(Master) --KDI School:Master of Business Administration,2006masterpublishedby Sergey Konovalov

Essentials of starting an online retail business in the North-West region of Russia

Research has covered the entrepreneurship activity in area of online retail sales, with attempt to identify key success factors and join them into a recommended system of key performance indicators (KPIs). There are a few studies in the areas of entrepreneurship, online commerce, business development in Russia, however, there is still no research done to identify the critical factors for success of new online shops, the possible pitfalls, and algorithms to ensure that businesses take off. The purpose of this study is to increase academic understanding of the online retail concept with the help of theoretical findings and practical data from case companies. The present research intends to give answers to several questions. What is the current state of knowledge about small and medium size online commerce in Russia? Are there any theoretical models and recommendations that can be used for this type of activity? What are the practical recommendations that can be made based on the experience of companies in this industry on KPIs and control points? To identify the current state of theoretical knowledge, the research of literature and other works have been done for the following areas: small and medium entrepreneurship, online commerce, business in Russia. Practical part was done in form of questionnaire-based interviews with managers and owners of selected real companies from North-West region of Russia, and analysing available quantitative information provided about business performance. The results of this work demonstrate that certain areas of focus of control exist to ensure development of new online retail stores which were grouped into the three main recommendations and a set of five key performance indicators

The contrasting oceanography of the Rhodes Gyre and the Central Black Sea

The Rhodes Gyre, a prominent feature of the oceanography of the eastern Mediterranean, is modelled as a vertical, continuous flow, cylindrical reactor illuminated during the day at its upper end. If the Gyre is supposed to be in a steady state whilst the concentrations, C, of a chemical are being measured, the nett rate of formation or consumption of the chemical is given by -w d C/d z + u d C/d r, where w is the upward velocity of the water in the vertical, z , direction and u is the velocity of the water in the radial, r, direction. The behaviour of w and u is analysed to show that the Gyre may be used as a field laboratory in which rates of chemical change may be derived from depth profiles together with values of the surface velocities of the Gyre waters. In contrast, the central Black Sea is modelled as an ideal, strongly stratified sea in which the nett rates of formation or consumption of chemicals under steady state conditions are given by Ds d2C/ds 2, where s is the water density and Ds is an eddy diffusion coefficient. Computations reveal that, given better knowledge of its eddy diffusion coefficients, the Black Sea can also be treated as a field laboratory where rates of reaction mediated by bacteria may be derived from depth profiles

Effect of the Stress State on the Adhesive Strength of an Epoxy-Bonded Assembly

The paper studies the adhesive strength of aluminum alloy specimens bonded with the use of an epoxy adhesive, under the tensile-shear stress state, depending on the testing temperature. Tension of modified Arcan specimens with load angles of 0, 22.5, 45, 67.5, and 90° with respect to the plane of adhesion is chosen as the experimental method. Experiments were performed at temperatures of −50, +23, and +50 °С. The analysis of the obtained results yields a linear fracture criterion and a fracture locus for the adhesive failure strain energy density, which takes into account the ratio of the elastic properties of the adhesive to those of the substrate. The region bounded by the fracture loci of adhesive strength and ultimate strain energy density determines the conditions for the safe loading of the bonded assembly in terms of the energy and force criteria of adhesive failure. The proposed fracture loci can be used, preferably simultaneously, to estimate the in-service strength and reliability of adhesively bonded assemblies

Comparative analysis of film boiling correlations for steam explosion problem

The article considers the existing models and correlations for describing heat transfer during film boiling. Film boiling is an important thermophysical process that determines the course of interaction of the melt of reactor core materials with the coolant, which can potentially occur during a severe accident at a nuclear power plant with a pressurized water-cooled reactor (VVER/PWR). The values of the Nusselt number predicted by these models are compared. A fairly significant dispersion of calculated parameters has been established, making it difficult to unambiguously choose one or another correlation. However, in the range of parameters typical for the interaction of a high-temperature melt of reactor core materials with a coolant, several correlations give quite close values, which allows them to be recommended for use in calculation codes for modeling thermal-hydraulic processes during a severe accident at a nuclear power plant with VVER/PWR type

Mathematical Modeling of the Concentrated Energy Flow Effect on Metallic Materials

Numerous processes take place in materials under the action of concentrated energy flows. The most important ones include heating together with the temperature misdistribution throughout the depth, probable vaporization on the surface layer, melting to a definite depth, and hydrodynamic flotation; generation of thermo-elastic waves; dissolution of heterogeneous matrix particles; and formation of nanolayers. The heat-based model is presented in an enthalpy statement involving changes in the boundary conditions, which makes it possible to consider melting and vaporization on the material surface. As a result, a linear dependence of penetration depth vs. energy density has been derived. The model of thermo-elastic wave generation is based on the system of equations on the uncoupled one-dimensional problem of dynamic thermo-elasticity for a layer with the finite thickness. This problem was solved analytically by the symbolic method. It has been revealed for the first time that the generated stress pulse comprises tension and compression zones, which are caused by increases and decreases in temperature on the boundary. The dissolution of alloying elements is modeled on the example of a titanium-carbon system in the process of electron beam action. The mathematical model is proposed to describe it, and a procedure is suggested to solve the problem of carbon distribution in titanium carbide and liquid titanium-carbide solution in terms of the state diagram and temperature changes caused by phase transitions. Carbon concentration vs. spatial values were calculated for various points of time at diverse initial temperatures of the cell. The dependence of carbon particle dissolution on initial temperature and radius of the particle were derived. A hydrodynamic model based on the evolution of Kelvin-Helmholtz instability in shear viscous flows has been proposed to specify the formation of nanostructures in materials subjected to the action of concentrated energy flows. It has been pointed out for the first time that, for certain parameters of the problem, that there are two micro-and nanoscale peaks in the relation of the decrement to the wavelength of the interface disturbance

Collapse and dynamics of a bubble near a rigid boundary enveloped by a vapor film

One of the possible consequences of a severe accident at a nuclear power plant with a pressurized water reactor is a steam explosion that occurs as a result of the interaction of a high-temperature melt of core materials with water and can lead to the failure of the containment. The paper considers the initial stage of the steam explosion (premixing of the melt with water) under the stratified geometry. The key phenomenon leading to premixing is the dynamic effect of a collapsing vapor bubble in a liquid on the melt surface. The influence of a vapor film located near a melt surface on the dynamics of a vapor bubble is considered. The Kelvin impulse is used as the main criterion characterizing the dynamic effect of a collapsing bubble on the liquid-vapor interface and on the melt surface. The influence of all the main parameters on the Kelvin impulse was numerically studied. Based on the calculations carried out on the plane of the parameters “film thickness - vapor density”, the region of the dynamic impact of the collapsing bubble on the surface is determined. The greatest impacts are observed for thin films of vapor having a high density

Modeling hydrodynamic flows in plasma fluxes when depositing metal layer on the surface of catalyst converters

Air pollution with harmful substances resulting from combustion of liquid hydrocarbons and emitted into atmosphere became one of the global environmental problems in the late 20th century. The systems of neutralization capable to reduce toxicity of exhaust gases several times are very important for making environmentally safer combustion products discharged into the atmosphere. As revealed in the literature review, one of the most promising purification procedures is neutralization of burnt gases by catalyst converter systems. The principal working element in the converter is a catalytic layer of metals deposited on ceramics, with thickness 20-60 micron and a well-developed micro-relief. The paper presents a thoroughly substantiated new procedure of deposing a nano-scale surface layer of metal-catalyst particles, furthering the utilization of catalysts on a new level. The paper provides description of mathematical models and computational researches into plasma fluxes under high-frequency impulse input delivered to electrode material, explorations of developing Kelvin-Helmholtz, Marangoni and magnetic hydrodynamic instabilities on the surface of liquid electrode metal droplet in the nano-scale range of wavelengths to obtain a flow of nano-meter particles of cathode material. The authors have outlined a physical and mathematical model of magnetic and hydrodynamic instability for the case of melt flowing on the boundary with the molten metal with the purpose to predict the interphase shape and mutual effect of formed plasma jet and liquid metal droplet on the electrode in the nano-scale range of wavelengths at high-frequency impact on the boundary "electrode-liquid layer"

Shock-induced structures in copper

Shock loading of M3 copper within strain rate range of 5·10 6-5,7·10 6 s -1 reveals a nucleation of structural objects of 5-30 µm in diameter, which present the three dimensional frameworks composed from shear bands of 50-200 nm spacing. The structures are shown to be nucleated by means of interference of longitudinal and periphery release waves. Transition of the material into structure unstable state responsible for the shear banding happens when rate of change of the velocity variance at the mesoscale becomes higher than the rate of change of the mean particle velocity. The sites of nucleation of 3D-structures are speculated to be the staking faults generated under action of chaotic velocity pulsations relevant to dynamic deformation. The physical model for formation of 3D-structures takes into account the intersection of the partial dislocations and Lomer - Cottrell barriers