The frequency-pulse method for determining the thermophysical characteristics of solid materials

On the basis of a linear instantaneous heat source, we consider the frequency-pulse method of determining the thermophysical characteristics of solid materials without destruction of their integrity. We present the results for the investigation of the procedural error in the determination of thermophysical coefficients by the method of numerical simulation, as well as the results of experimental investigations. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 2, pp. 336–341, March–April, 1998.     

Nondestructive techniques for determining the thermophysical characteristics of materials by the instantaneous-heat-source method

Using the method of a linear instantaneous heal source, we consider nondestructive techniques for determining the thermophysical characteristics of materials. A procedure for estimating errors in the techniques suggested is given. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 6, pp. 888–894, November–December, 1997.     

A method for determining thermophysical characteristics based on the laplace transform

A method for processing the results of measurements after application of the Laplace transform is proposed for determining thermophysical characteristics by the method of a source of constant power, with the heat capacity of the heater taken into account.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 52, No. 2, pp. 287–293, February, 1987.     

A quasi-steady method of determining the thermophysical characteristics of solids

We consider a comparative quasi-steady method of determining thermophysical characteristics. Computational formulas are derived for the symmetric and nonsymmetric heating of plates. We present theoreticala- and -data for mycalex, derived on the basis of this method.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 15, No. 6, pp. 1106–1113, December, 1968.     

Extension of the quasilinear method of determining thermophysical characteristics to the case of anisotropic materials

The article reports on the initial part of the stage of regular thermal regime of a plate heated by a constant heat flux, and a method is suggested for determining thermal conductivity and thermal diffusivity.Notation T temperature of the plate - T₀ binitial temperature of the plate and ambient temperature - g volume density of the heat sources - q heat flux density - _x thickness of the plate - _x thermal conductivity along the x axis - a _x thermal diffusivity along the x axis - heat transfer coefficient - Fo Fourier number - B Biot number - density of the material of the plate - c heat capacity - t time Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 55, No. 4, pp. 611–616, October, 1988.     

A two-mode microwave cavity method of determining the volume fraction of water in a liquid fuel lubricant

A two-mode microwave cavity method is proposed for determining the volume fraction of water in liquid fuel lubricant materials. The volume fraction of water is determined from the difference between the resonant frequencies for the H₀₁₁ and E₁₁₁ modes. Experimental results are given. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 58–61, March, 2008.     

A differential method of determining the thermal properties of materials

A method for determining the thermal properties of materials is described, which enables one to distinguish small differences in the thermal properties of two specimens. Only two galvanometer readings need to be taken. The method belongs to the category of electrical measurements of nonelectrical quantities.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 2, pp. 268–273, February, 1971.     

A method for determining the residual stresses in fibrous composite materials

A method for determing the original residual stresses in a composite material is suggested, in which the stress/strain curves for the matrix and composite are compared. The changing residual stresses in the components of a model composite, which are dependent upon the amount of prestraining, were analysed; the model composite consisted of elastic fibres and an elastic-plastic matrix, having linear work hardening. Formulae are presented for determining the amount of prestraining needed to give rise to compressive residual stresses in the matrix equal to the compressive yield stress, and for determining the volume fraction of fibres in the composite when, after prestraining, the compressive residual stress equals the compressive yield stress. An experimental examination of the theoretical conclusions has been conducted using an aluminium alloy/steel wire composite.     

Flat-probe method for determination of the thermophysical properties of massive materials

A method of nondestructive measurement of the thermophysical properties of massive materials is proposed in which the heat leakage of the heater to the surrounding medium is accounted for and the distorting influence of its heat capacity on the temperature field of the sample is eliminated.Institute of Permafrost Science, Siberian Division, Russian Academy of Sciences, Yakutsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 64, No. 2, pp. 221–227, February, 1993.     

A novel method to measure the porosity of porous materials

ABSTRACT

Porosity is the single most important feature of porous materials. On the basis of the research work, a new method to measure the porosity of porous materials is proposed in this paper. This method is a system of equations composed of six formulas, so it is called model equation method. It is not only applicable to space holder technique but also applicable to metal prepared by pure powder metallurgy. Compared with mass volume method and immersion medium method, our new method is more simple and efficient. More importantly, it can be used as a standard measure. This study provides a fundamental basis for the measurement of porosity in porous materials.     

Nonlinear water diffusion in unsaturated porous solid materials

Water diffusion in unsaturated porous solid materials is investigated in the present study. The hydraulic diffusivity of water diffusion is seen to be adequately represented only by a highly nonlinear water content-dependent function. The nonlinear physical model can be efficiently tackled by the orthogonal collocation method. Numerical simulations of the water diffusion model in various porous solid materials are shown to agree well with the experimental observations. The physical model with nonlinear water content-dependent hydraulic diffusivity can be employed to predict the behavior of water movement in the unsaturated porous materials.