Existing and prospective blast-furnace conditions

Blast-furnace conditions are investigated by means of a multizone model. The expected performance of prospective technologies is assessed, as well as the trends in blast-furnace processes. The model permits the identification of means of overcoming practical difficulties.     

On modeling of the biophysical field of a human joint in tribological experiments in vitro

Analysis of the development of ideas concerning the bioelectrical fields of living organisms shows that approaches to the modeling of the electromagnetic field of synovial joints in experiments in vitro have not yet been developed. The current work considers the biophysical and biochemical processes of the formation and circulation of synovia in joints, which are controlled by their natural electromagnetic field. The basic conditions are determined of the adequacy of the effect on friction and lubrication of a natural biofield in a synovial joint and of an external electromagnetic field in a friction pair that imitates a joint. Examples of the modeling of the electromagnetic field of the joint in experiments in vitro are given, demonstrating the pronounced effect of the external field on the lubricity of synovia.     

Detection of X rays from a high-current discharge in a dense gaseous medium

An experimental complex for detecting X-ray self-radiation of a high-current discharge in a dense gas is described. Methods for protecting the radiation detector from the effects of high pressure, temperature, and shock waves are considered. The factors affecting the accuracy of measurements are analyzed. Experimental results and an analysis of them are presented.     

Tunable microstrip resonators with ferroelectric capacitors

The question of increasing the tuning band of microstrip resonators that use ferroelectric capacitors for tuning in the region of increased electric lengths is considered which allows using them in the upper part of the centimeter band (Ku-band, K-band). Band properties of regular and step-irregular resonators operating at the lowest resonant frequency are analyzed.     

An experimental stand for studying a high-current discharge in a dense gas

Experimental studies performed at the Institute for Electrophysics and Electric Power, Russian Academy of Sciences, that aimed at both the study of physics of a high-current pulsed discharge in a superdense gas and the improvement of various prototypes of pulsed facilities allowed a number of physical phenomena characteristic of these processes to be revealed. The most interesting phenomena are the arc contraction and a considerable increase in the electric-field strength in the arc channel with an increase in the initial particle density over 10²² cm^?3. A substantial increase in the sum of the near-electrode voltage drops is observed with a rise of the discharge-current amplitude. A setup is described and the measurement results at an initial particle concentration of up to 10²² cm^?3 and a discharge-current amplitude of up to 2 MA are presented.     

Modification of poly(ethylene terephthalate) fibres with bactericides with the craze formation mechanism

The possibility of immobilizing bactericides on PET fibres by the craze formation mechanism was demonstrated. Of the bactericides investigated, Al (althosan) was a more active modifier of the fibres than Ct (catamine). The resistance of the bactericidal fibres to “wet” treatments simulating laundering conditions was demonstrated, and this allows using fabric articles made from them for a long time. __________ Translated from Khimicheskie Volokna, No. 5, pp. 34–38, September–October, 2006.     

Microstrip resonators with extended range of capacitive tuning

The analysis of different step-impedance microstrip resonators with extended range of the capacitive frequency tuning has been performed. The specified resonators are capable of operating in a wide wave range, including the meter and centimeter radio waves. The resonance equations were obtained and the problem of separating the oscillation modes was considered, and distinctive features of these resonators were established. Recommendations are made regarding the use of the specified resonators at different frequencies (VHF-band, K-band). It is shown that the use of step-impedance resonators and ferroelectric capacitors having the relative variation of capacitance C _max/C _min = 2.2 in the frequency range of 20GHzand higher makes it possible to achieve the tuning bandwidth as large as 28%.     

Evidence of the illegitimacy of the additive approach to the determination of the thermophysical properties of coal-water fuel with glycerol

For the fuel ignition, the thermal conductivity and heat capacity are the key properties that determine the pre-ignition behavior of the drop of the fuel. The classic monophase fuels, such as natural gas, liquid propellants, or solid one-component fuels, have been investigated for a long time; and their thermophysical properties are well known in most of the cases. Composite fuels, which have recently attracted the attention of the researchers, have complex contents. In many cases, composite fuel is a mixture of solid and liquid components in the form of a slurry. Coal-water fuel and its derivatives with different additives are examples of such type fuels. For those fuels, the thermophysical properties are usually unknown. Nowadays, researchers use simple additivity theory for the calculation of the thermophysical properties of complex fuels for the first approach. Authors of this research believe that the simple additivity approach is not correct and can lead to the wrong results in the case of the numerical research of the ignition and burning processes of such a fuel. In the present research, the thermophysical properties of coal-water fuel with glycerol additives were experimentally obtained. It was found that the coefficient of thermal conductivity increases with temperature and varies in the range of 0.45 to 0.53 W/(m·K). The heat capacity of the fuel also increases with the temperature and varies from 4.7 to 5.5 kJ/kg·K. The higher the glycerol content, the lower the thermal conductivity and heat capacity of the composite fuel in the investigated temperature range. The results confirm the failure of the approach of the additivity law usage. Neither, thermal conductivity coefficient or heat capacity of the coal-water fuel with the addition of up to 20% glycerol complies with the additivity law. Differences between real values of the thermophysical properties and calculated ones are more than 30% to 50%. Empirical expressions for calculation of the thermophysical properties of coal-water fuel with the addition of up to 20% glycerol are presented.