Modeling of the Thermophysical Processes in Sintering Glassware

A complex approach to the modeling of the thermophysical processes in glassware obtained by the sintering technique is proposed. A onedimensional model of radiativeconductive heat exchange in a layer of a transparent scattering material formed from glass particles and a model of twodimensional heat conductivity in a multilayer molding rig with an article are considered. The results of mathematical modeling are presented.     

Proton Irradiation Effects on Thermophysical Properties of High-Thermal-Conductivity Graphite Sheet for Spacecraft Application

This paper describes an evaluation of the proton irradiation effects on the thermal characteristics of a pyrolytic graphite sheet (PGS), which has characteristics of high thermal conductivity, light weight, and flexibility, in order to apply this material to an advanced spacecraft thermal control device, the reversible thermal panel (RTP). The results show slight changes in the in-plane thermal diffusivity and total hemispherical emittance of the PGS for 2.0 MeV proton irradiation. An RTP prototype model based on the PGS was designed and fabricated, and its thermal performance was evaluated. The effects of changes in thermal characteristics of the PGS on the thermal performance of the RTP were also discussed.Paper presented at the Seventh Asian Thermophysical Properties Conference, August 23–26, 2004, Hefei and Huangshan, Anhui, P. R. China.     

Modeling of Heat Outflows to a Probe in Thermophysical Testing

The nondestructive method developed by the author with the use of a linear pulsed heat source makes it possible to determine the thermophysical characteristics of solid materials on the basis of the portions of thermograms that correspond to the regularization of the thermal regime in the region of the heater and temperature detectors. Consideration has been given to the influence of the outflows of heat to a probe on the error in determining the thermophysical characteristics of materials in the case where two semiinfinite bodies are in ideal contact. A mathematical expression upon the fulfillment of which one may disregard the heat loss to the material of the probe substrate has been obtained. In the work, consideration has also been given to the problem of heat loss to the probe material in the case where it occurs only in the region of the heater. It has been shown that the temperatures of the first and second bodies in the contact area will become closer with time. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 4, pp. 108–116, July–August, 2005.     

Modeling the Processes Involved in the Leakage of Gas from a Spacecraft Module

Analytical expressions are obtained to describe the change in the pressure and flow of a gas over time through openings of different shapes in the hull of a spacecraft. Results are presented from experimental studies.     

Mathematical Modeling of the Heat Exchange of the Payload Module of Nonhermetic Geostationary Spacecraft

Dynamic thermal mathematical models in lumped and distributedlumped parameters, computational algorithms, software, and results of comparative numerical calculations of the processes of radiativeconductive heat exchange of the payload module of prospective nonhermetic blockmodular geostationary spacecraft with a long service life under the conditions of orbital operation have been presented.     

Special Features of Propagation of Peat Fire

The laws governing propagation of peat fire under varying outer conditions and different moisture contents are studied. Critical values of moisture content and the conditions of heat and mass exchange of a peat bed and the surrounding medium under which combustion can stop are determined based on numerical calculations. It is found that under certain conditions the combustion wave propagates along the peat bed even in the absence of air influx from the outer medium. The assumption that in small losses of heat to the outer medium the combustion wave will propagate along the bed surface and in intense heat transfer it will move into the depth of the bed is confirmed. It is shown that in combustion of a thick bed of peat layerbylayer combustion may take place.     

Thermophysical properties of elastomers

The following account describes investigations of dimensional and stiffness characteristics of representative polyacrylic and silicone rubbers over the approximate temperature range 20 °C–175 °C. The results have led to a quantitative understanding of distinctive features in the behaviour of these elastomers, encountered during the course of their repeated use as tool materials in composite component manufacture, conforming with an explanation in terms of thermally induced cross-linking. It is concluded that silicone rubber offers more promise than polyacrylic rubber in applications where behavioural stability and a reasonable degree of control are required.     

Thermophysical properties of rhenium

Experimental investigations of the thermophysical properties of rhenium at high temperatures (above 2000 K) are scarce and quite recent. Using an isobaric expansion technique, we performed new measurements up to 7000 K under 0.12GPa argon pressure and report here enthalpy, density, temperature, and electrical resistivity data for both solid and liquid states. Agreement is good with other pulse heating results obtained on this refractory metal (T _m =3453 K), except in the volume increase at melting.Paper presented at the Third Workshop on Subsecond Thermophysics, September 17–18, 1992, Graz, Austria.     

利用全光谱特种照相取证仪去除指印的背景干扰

目的：研究去除现场指印背景干扰的技术方法。方法：采用全光谱特种照相取证仪的主光源,以10—30度的入射角照射具有背景干扰的现场指印．并结合该设备的滤光系统进行分色照相。结果：显现出亮纹线暗背景的指印图像,指印背景无干扰。结论：采用全光谱特种照相取证仪可以消除指印的背景干扰,为指印显现提供了一种新的设备。     

Modeling of Microaccelerations Caused by Running of Attitude-Control Engines of Spacecraft with Elastic Structural Elements

The article deals with the task to estimate microaccelerations caused by natural oscillations of big elastic elements after impulse firing of an orientation system engine. Offered estimation is useful for development of space-system engineering intended for realization of gravity-sensitive processes. It can be applied for taking a decision about appropriateness of one or another process on the board of spacecraft.     

Modeling of Customer Preferences on Product Features and Comparing the Competitors' Performances

Understanding of consumers' perception about various product features helps companies to identify their own strengths and weaknesses. This article aims at finding the relative brand position of a company along with the nature of preference as perceived by the customers towards its major competitors. Information obtained through a feedback survey was subjected to analysis using multivariate statistical techniques. Feature-based preferences by the customers to evaluating companies' performances in the retail footwear market are reported here.     

Thermophysical properties of oil shales

Recent developments in the characterization of the thermophysical properties of various types of oil shales are reviewed. Changes in the thermal, mechanical and electrical properties of these technologically important materials are discussed, with temperature and organic content as the experimental variables. Structural models are presented to aid in predicting the variation of thermophysical parameters with organic content in the shale. Comparison of calculated results with experimental data are shown with thermal diffusivity as a representative parameter. Areas where further research of a fundamental nature would be of particular relevance are also highlighted in the review.     

Thermophysical properties of liquid iron

Wire-shaped iron samples are resistively volume heated as part of a fast capacitor discharge apparatus. Measurements of current through the specimen, voltage across the specimen, radiance temperature, and thermal expansion of the specimen as functions of time allow the determination of specific heat and various dependencies among enthalpy, electrical resistivity, temperature, and density for liquid iron up to 5000 K. High pressures. up to 3800 bar, are used to obtain the liquid state far above the normal boiling point. An estimate of critical-point data for iron is given by using experimental data of the vapor pressure of liquid iron.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Thermophysical Properties of Swine Myocardium

This paper presents the experimental technique and results for the thermal conductivity, thermal diffusivity, and density of swine myocardial tissue. These properties were measured for freshly excised tissue. Thermal properties were measured using a self-heated thermistor probe, while the density was measured using a water displacement method. Thermistor probes were inserted into the tissue of interest and were used to supply heat within the tissue as well as to monitor the temperature rise in the tissue. An empirical calibration procedure was used to measure the properties of the tissue at different temperatures. The measurement instrument was first calibrated against agar-gelled water and glycerol at each temperature. The measurements were made at temperatures of 25, 37, 50, 62, and 76°C. The uncertainty in the measurement ranges from 2% at lower temperatures to about 5% at higher temperatures (T > 50°C). The properties of the tissue depend significantly on the water content. At temperatures higher than 50°C, there is significant water loss from the tissue during the procedure. The water loss is found to vary exponentially with the increase in temperature relative to ambient. Consequently, there is a decrease in the thermal conductivity values with increasing temperature. This decrease, however, is not as much as one would expect from the water loss data. A hypothesis to explain the relationships among water loss, cell damage, and thermal properties is proposed.     

Thermophysical properties of dispersion-hardened nickel

The thermophysical properties of dispersion-hardened nickel were measured over the following temperature ranges: thermal conductivity and electrical resistivity from 20 to 1300°C, integral hemispherical emissivity and spectral emissivity (λ=0.65 μ) from 1000 to 1300°C.     

Thermophysical properties of asbestos-reinforced rubbers

Factors influencing the sealing characteristics of gaskets made from asbestos-reinforced rubbers include mechanical properties, thermal properties and moisture absorption characteristics. Existing knowledge of the temperature dependence of the mechanical behaviour has been augmented by investigations of the specific heat capacity, thermal expansion and thermal conductivity at temperatures up to 250° C, as well as moisture absorption characteristics at ambient temperature of as-prepared and thermally cycled material. The measurements have provided an insight into thermally induced structural changes within the matrix, which are relevant to component operation.     

Thermophysical properties of scandium-titanium alloys

We present the results of measurements of the specific heat capacity of scandium-titanium alloys in the 4.2–12°K range and their electrical resistivity in the 4.2–300°K range.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 4, pp. 587–592, April, 1980.