Phase In Such Systems Research Articles

New Gallides and Germanides of Transition Metals

The analysis of the average atomic volumes (AAV) of the intermediate phases from the concentration was done in many two-component systems. It was shown that in some systems (namely transition metal with non-transition element from the IIIrd or IVth group of the periodic table) the AAV of the intermediate phases are much more less than the sum of the volumes of the pure components. It means that the formation of the intermediate phases in such systems is accompanied by a rather large decreasing of the volume in comparison with the mixture of elements. For this reason the high pressure conditions are favourable for the formation of the intermediate phases in such systems from the thermodynamical point of view. On the ground of these data the systems W-Ga, W-Ge, Re-Ga, Os-Ga, Sc-Ga, Ta-Ga, were investigated at high pressures and temperatures. It was found that many new phases are crystallised in these systems. All of them are metastable at room pressure. The composition and crystal structures of these phases were investigated at ordinary conditions.

Phase Behavior of CO2 and Crude Oil in Low-Temperature Reservoirs

Abstract Phase behavior of CO2/crude-oil mixtures which exhibit liquid/liquid (L/L) and liquid/liquid/vapor (L/L/V) equilibria is examined. Results of single-contact phase behavior experiments for CO2/separator-oil mixtures are reported. Experimental results are interpreted using pseudoternary phase diagrams based on a review of phase behavior data for binary and ternary mixtures of CO2 with alkanes. Implications for the displacement process of L/L/V phase behavior are examined using a one-dimensional finite difference simulator. Results of the analysis suggest that L/L and L/L/V equilibria will occur for CO2/crude-oil mixtures at temperatures below about 120° F (49 °C) and that development of miscibility occurs by extraction of hydrocarbons from the oil into a CO2-rich liquid phase in such systems.

Aerodynamic aspects of transfer processes in heterogeneous fluidized systems

A hypothesis is proposed concerning the occurrence of a critical state in fluidized systems, associated with the transition from a small-scale to a large-scale mixing of the solid phase, when the excess fluid velocity U e reaches the particles' free-falling velocity U t. It has been shown that some transfer processes concerning the motion of the solid phase in such systems take place at the critical state with a maximum intensity. A method is proposed for determining with satisfactory accuracy the velocity coordinate corresponding to the maximum values of the transfer characteristics.

Electron Microscopy of Lyotropic Mesomorphic Phases

Abstract Electron, microscopy can provide direct visual confirmation of mesomorphic phase structure in surface-active agent + water systems. Several different specimen preparative techniques have been used to examine the structures of the two most commonly occurring mesomorphic phases in such systems, neat phase and middle phase. Surface replicas of both anhydrous and quench-frozen specimens have clearly illustrated the domain structures which give rise to the characteristic optical textures of these two mesomorphic phases. In several systems osmium tetroxide fixation followed by thin sectioning has permitted the examination of neat and middle phase structures in cross-section. Polymerisation of a suitable compound in the mesomorphic state has provided non-labile structures for examination in the electron microscope as thin sections, using either pre-or post-staining with heavy metal reagents.