Stability of the boundary layer of liquid under a nonuniform temperature distribution of the surface

We study the effect of a longitudinal gradient of the surface temperature on the stability of the boundary layer of an incompressible liquid. A comparison shows a good agreement of the results with experimental data.     

Ivan Nikitich Frantsevich and His Scientific School

In 2000 there are two dates associated with Ivan Nikitich Frantsevich: his 95th birthday and the 15th anniversary of his death. In that connection, the Frantsevich Institute for Problems of Materials Science has set up a series of lectures in his memory. The materials of those lectures are published in this issue in accordance with the decision of the editorial board.     

Modified track membranes with antibacterial properties

Microbiological contamination of polymeric membranes in the process of their exploitation is an essential problem of membrane technology. It results in the increase of manufacturing costs, destruction of membranes, operating life reduction and secondary contamination of water by the metabolism products of microorganisms. For the purpose of reduction of membrane biofouling and biodegradation investigation of adsorption of the guanidine containing oligomers on the surface of PET track membranes was conducted and their influence on the selectivity and antibacterial properties of the membranes was investigated. It was established that modified membranes have substantially higher resistance to biofouling.     

Two Phase Flows in Porous Media Under Microgravity Conditions

The paper presents the results of investigating the instability of the displacement of viscous fluid by a less viscous one in two-dimensional and three-dimensional porous specimens. The effects of the three-dimensional phenomena on development of instability are revealed, in particular, the faster growth of 3D disturbances as compared with 2D ones, while 2D displacement integral parameters (such as the outflow of the displacing fluid) have much higher deviations than those parameters obtained in 3D modelling. This can be explained by much higher number of fingers in 3D cases of displacement reaching the outflow surface, and by the subsequent compensation of disturbances in the overall outflow.     

Sonochemical Preparation and Properties of Pt–3Y-TZP Nano-Composites

A uniformly aggregated 3 mol% yttria-stabilized tetragonal zirconia nano-powder (3Y-TZP) was prepared using thermal hydrolysis and the ultrasonic deagglomeration technique. The possibility of nano-engineering of Pt–3Y-TZP composite aggregates was studied. The as-synthesized Pt nano-particles (∼2 nm) were impregnated into zirconia nano-aggregates (20–45 nm). The morphology manipulation technique allowed production of the composite zirconia-based aggregates in which a significant fraction of the Pt particles was embedded into the densified zirconia aggregates. Using the colloidal technique and low-temperature (1150°C) sintering, we prepared the Pt-zirconia (0.5–1.5 wt% of platinum) nano-composites with average 3Y-TZP grain sizes of 120 nm, and with the platinum grains size in the range of 20–60 nm. The catalytic properties of composite Pt–3Y-TZP nano-composites were studied and described.     

Substantiation of the predicted fatigue curve for structural elements of aluminum alloy

The paper provides a more specific definition of the method for calculating fatigue life of aluminum alloy structural elements by a local stress-strain state in pulsating regular loading. The calculated results are compared to the test data for specimens with a free and filled holes and for lugs. Recommendations on the method application for calculating fatigue life by nominal stresses are given.     

Mathematical modelling of thermal conductivity process in salt-contaminated wall materials

The results of computational investigations dealing with the influence of moisture and salt on the effective thermal conductivity of the masonry wall were presented. The investigation was carried out on the basis of mathematical modelling of heat transfer in capillary-porous materials. The dependencies between the thermal conductivity of the wall and the content of moisture and salt, as well as the physical state of salt were described. The assessment of the degree of salt influence on the thermal conductivity of masonry wall for the admissible exploitive moisture content was performed. Practical formulae were obtained and presented for realistic estimation of the effective thermal conductivity of ceramic brick and masonry wall.     

Removing of light hydrocarbons from gas mixtures using polymeric composite membranes based on poly(1-trimethylsilylpropyne)

Usually the methodologies used to analyse the feasibility of water reuse projects are focused on the internal costs. The aim of this paper is to show a methodology to assess the feasibility of a water reuse project taking into account not just the internal impact, but also the external impact (environmental and social, for example) and the opportunity cost derived from the project. Internal benefit is obtained from the difference between internal income and internal costs. Internal income is obtained by multiplying the selling price of reclaimed water and the volume obtained. Internal costs are made up of the sum of investment costs, operating costs, financial costs and taxes. While some of these factors identified can be calculated directly in terms of money, biophysical and social aspects demand the definition of units of measurement. In order to homogenize results, an annual reference is proposed. A monetary value can be obtained from the calculation of each impact. However, there are a series of externalities for which no explicit market exists. In these cases economic valuation methods are used, based on hypothetical scenarios or patterns observed in related markets.     

Constructing an earth dam with a metal diaphragm in Zapolyar

Conclusion Experience with the construction of the dam with the metal diaphragm, which serves the Serebryanka No. 2 hydroelectric power station, has shown that for regions of the Extreme North, these dams are considerably more economical than dams with earth antiseepage elements, and the procedure employed for their installation is quite simple. Translated from Gidrotekhnicheskoe Stroite'stvo, No. 12, pp. 6–11, December, 1975.