Effects of porosity and related interstitial phase morphology difference on the grindability of clinkers

The effects of regional clinker porosity and interstitial phase morphology differences on grindability of clinkers have been investigated within the scope of this study. Porosity and phase characteristics of two clinkers from different furnaces which are using the same raw materials were determined by the application of image processing techniques on SEM images of polished surfaces. Comparison of interstitial phase compositions of two clinkers showed that, clinkers with similar phase compositions may have different grindability due to the porosity and phase morphology differences. Porous clinkers usually exhibit a dendritic interstitial phase morphology with an improved grindability. Increasing porosity also leads to greater incidence of the dendritic morphology in porous regions and lower incidence of alkali in the aluminate in dendritic regions.     

Pyroelectroluminescence of barium beta borate single crystals

Investigations were made of the pyroluminescence properties of barium beta borate single crystals. The measurements were made at air pressures of 1–10 Pa and temperatures of 80–400 K. Luminescence was observed as isolated flashes over the entire range of experimental conditions. It was observed that the light flashes coincided with the pyrocurrent oscillations. Pis’ma Zh. Tekh. Fiz. 24, 62–65 (February 26, 1998)     

Cold-cavity vectorial eigenmodes of VCSELs

An analytical approximate solution of Maxwell's equations for the cold-cavity eigenmodes of cylindrical etched air-post vertical-cavity surface-emitting lasers (VCSELs) is presented. In radial and azimuthal directions, the modes correspond to the hybrid modes of cylindrical optical waveguides. A vectorial transform matrix approach is derived which takes into account coupling of bound eigenmodes in VCSEL structures. The method is illustrated for the case of noncoupled modes and the corresponding simplified transform matrix approach is used to calculate the field profiles in longitudinal direction and predict the resonance wavelengths for the VCSEL eigenmodes. Although approximate, the resulting eigenmodes may be viewed as a useful alternative to full numerical solutions, especially with regard to future more comprehensive modeling of VCSELs     

A brief survey and economical analysis of air cooling for electronic equipments

The techniques used in the cooling of electronic equipments vary widely depending on the particular application. Cooling with liquids and impinging air jets become important where classical cooling techniques may be insufficient, while a single or array jet is employed where highly localised cooling is desired. This paper provides a comparative survey of advanced methods of cooling for electronic systems and an economical analysis of cooling electronic equipments using slot and circular jets.     

Simulation and investigation of mechanical and concentration fields in near-contact regions of two-component piecewise uniform systems

We suggest a system of equations that describes correlated mechanical, thermal, and diffusion processes in binary solid solutions with account for surface effects within the framework of a three-dimensional approach. Using this system, we investigate near-contact singularities of mechanical and concentration fields in layered systems with flat boundaries. The results obtained can be used in choosing coatings with optimum strength and reliability.Pidstrygach Institute of Applied Problems in Mechanics and Mathematics, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 1, pp. 78–88, January–February, 1994.