The present work examines numerically the effect of thermal radiation from the solid phase on the fluid and solid temperature fields inside a porous medium by studying forced convection heat transfer process within a pipe filled with a porous material. The Darcy–Brinkman–Forchheimer model is utilized to represent the fluid transport within the porous medium. A local thermal non-equilibrium (LTNE), two-equation model is used to represent the energy transport for the solid and fluid phases. The radiative transfer equation is solved by discrete ordinate method (DOM) to compute the radiative heat flux in the porous medium. Two primary approaches (models A and B) are used to represent the boundary conditions for constant wall heat flux. Firstly for a fixed model, the effects of radiative heat transfer from the solid phase on the temperature profiles of the two phases are analyzed for different parameters such as porosity, Darcy number, solid-to-fluid thermal conductivity ratio and inertia parameter. Secondly, the effects of radiative heat transfer on the temperature distributions and Nusselt numbers for the two phases are examined by comparing the result obtained by application of models A and B. The results demonstrate that ignoring the effect of thermal radiation from the solid phase leads to a substantial error in prediction of the solid and fluid temperature fields and validity of the local thermal equilibrium (LTE) between the two phases. The solid and fluid temperature fields obtained for the radiative case are substantially lower than those obtained for the non-radiative case. Further, it is seen that the thermal radiation from the solid phase leads the temperature fields to the LTE condition. Depending on the pertinent parameters and compared to the non-radiative case, for the radiative case up to 50% decrease in the non-dimensional temperature differential is computed between the two phases. The Nusselt number obtained by application of model A for the radiative case is higher than those predicted for the non-radiative case. While, for model B the fluid Nusselt numbers obtained for the radiative and non-radiative cases are similar.

On the basis of the thermodynamics of irreversible processes, a solution has been obtained for the problem of mass transfer between nonfreezing interlayers in a slit model of a pore filled with ice, and also between the thawed and frozen zones of a porous solid. The disjoining pressure plays a role in determining the equilibrium thickneses of the interlayers and in the phenomena of frost damage and heaving of soils. The theory that is developed in this work is supported by experimental findings, and guidelines are formulated for future research in the field of the theory of moisture movement in porous solids during the freezing process.

Refinement of the theory of diffusiophoresis in regard to ion dispersion from latices (with corresponding experimental support for the theoretical results) and experimental studies conducted under conditions similar to actual production conditions have shown that the first period in the formation of the gel film is the result of coagulation of the latex when it comes into contact with the highly concentrated electrolyte (this occurs despite the fact that particle diffusiophoresis is directed away from the electrolyte-latex interface). Electrolyte concentration at the gel-latex boundary decreases after a sufficient number of particles have accumulated in the gel. This marks the beginning of the second period in the formation of the film, governed by diffusiophoresis of particles toward the electrolyte-latex interface. Thus, the film of latex gel consists of two layers with different structures and, of course, different properties. Future development studies and commercial trials of such films will make it possible to optimize the conditions for the production of films with prescribed properties while eliminating certain types of defects.

Nonlinear current-voltage and coulomb-voltage characteristics with a hysteresis loop, which is peculiar to ferroelectrics, were observed in the boundary layers of individual saturated organic acids and oleic acid which have a domain structure and also an anomalously high conductivity which corresponds, in its order of magnitude, to the lower conductivity limit for metals. These effects are related with the formation of a volume space charge and by the cording of the current (formation of conductivity channels). The electrical properties of the boundary layers change in relation to the thickness: for subcritical thicknesses Ohm's Law is obeyed but for larger thicknesses strong field effects are observed. The thickness at which the system changes into the nonconducting stage has meaning as a physical characteristic of the system.

Resonance measurements at 7.5 × 105 Hz reveal a measurable bulk shear elasticity for various liquids (water, acetone, benzene, alcohols, acetic acid, CCl4, oil). The shear modulus of a nonpolar liquid is independent of the layer thickness. A polar liquid shows a sharp increase in the shear elasticity at distances less than 10-5 cm from the surface of the quartz.

The relative expansion of water in pores about 50 Å in size has been investigated within the temperature range of 0 to 90°C. It has been established that at a temperature higher than 70°C, the runs of curves in pores and the bulk phase coincide. This demonstrates that the structural peculiarities of water disappear at these temperatures. Comparison between the plotted curves enables one to evaluate the density of water in pores, which at room temperature differs from the bulk density by about 2%.

As demonstrated previously, with high concentrations of electrolyte, particles move toward a decrease in the concentration of electrolyte. Two stages were thus found in ion deposition from latexes: the process is initially due to coagulation of the latex, then diffusion of the electrolyte through the latex film continues, causing a decrease in the concentration of the electrolyte, and diffusiophoresis consequently becomes directed toward the model.