Effect of hydrophobization of powdered fillers on properties of polymer-based composites

Possibility of filler hydrophobization by treatment with organosilicon compounds as well as influence of the treatment on the composite properties has been studied. Diatomite and tripoli were used as fillers, epoxy resin as binders, and polyorganohydridesiloxane (polyethylenehydrosiloxane) liquid GKZh-94 as a hydrophobic additive. The latter was found to markedly increase the filler specific surface area by 12.9 to 31.6% for the same time of treatment in a ball mill. It was shown that the optimum amount of organosilicon additive is 0.16%. It was found that after addition of GKZh-94 moisture absorption by the test fillers decreased roughly by 2.5 times and that polyorganohydridesiloxane liquid facilitates increase in ultimate bending strength of composites by 33.3–38.9%.     

Membership problem for differential ideals generated by a composition of polynomials

The question of whether a polynomial belongs to a finitely generated differential ideal remains open. This problem is solved only in some particular cases. In the paper, we propose a method, which reduces the test of membership for fractional ideals generated by a composition of differential polynomials to another, simpler, membership problem.     

Effective lake basin management institutions: lessons from African lakes.

Weak or non-existent institutions are often cited as a major constraint facing management of many lake basins in Africa. By their nature lake basins cut across many sectoral and jurisdictional interests and therefore it is always the case that management of the basins is affected by actions within the various sectors and jurisdictions. Because of the complex nature of issues within lake basins, authority over management of lake basins is dispersed among several institutions, with no single institution having overall authority. Under these circumstances, a major challenge in lake basin management is how to ensure effective coordination among the various players. This paper reviews the situation of lake basin management at eight African lake basins and draws important lessons about lake basin management institutions. It is noted that fragmented approaches, lack of coordination across sectors, and lack of monitoring and enforcement are major institutional weaknesses. Also, it is observed that political will and commitment are essential for the management of African lake basins.     

Prospects for successful introduction of pisciculture to reservoirs intended for water-power generation

Successful introduction of pisciculture to reservoirs by the method of migratory fish-farm pasturing is described. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 9, September 2007, pp. 36–40.     

Equilibrium distribution of water in the two-phase system supercritical carbon dioxide–textile

When natural fibres are dyed in supercritical carbon dioxide, the addition of a small amount of water increases coloration. For a process design it is important to know how much water has to be added to obtain a desired humidity of both textile and carbon dioxide. In this work a thermodynamic model is proposed to calculate the distribution of water over the textile phase and the supercritical phase as a function of pressure and temperature. The phase equilibrium is described with Raoult's law for non-ideal fluids. The absorbed water in the textile is a condensed phase and is modelled here as a non-ideal liquid, using the NRTL-equation. The non-ideality of the supercritical phase is described by a solubility enhancement factor, a new equation derived from statistical thermodynamics. Although the model is applied to cotton, viscose, silk and wool, it can be used for all water absorbing textiles.     

Adapting a mathematical model of the end of the blow of a converter heat to existing conditions in the oxygen-converter shop at the Magnitogorsk Metallurgical Combine

The authors have constructed a deterministic dynamic model that makes it possible to predict the carbon content and temperature of steel at the end of the blow in oxygen converter steelmaking. Instrument measurements of different parameters of the heat are used to calculate the deviations of the parameters’ prescribed values from their actual values. Calculations are performed to determine the corrective additions that need to be made to a heat to synchronize the decarbonization and heating of the bath.