Heat-resistant properties of cement stone with finely milled refractory additives

The behavior of the structure of cement stone is investigated as a function of the heating temperature. The physicochemical processes occurring in cement stone under the effect of high temperatures are described. The variety of binding compositions makes it possible to control the requisite properties within a wide range and take into account the requirements imposed on heat-resistant concrete regarding the rate of hardening, strength, heat resistance, and other properties. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 5, pp. 10–11, May, 1996.     

Crystallization mechanism and characteristics of silicomanganese slag melts used to make glass ceramics (Review)

Translated from Steklo i Keramica, No. 3, pp. 2–5, March, 1993.     

Pneumothorax. A complication of fine needle aspiration of breast tumors

Of 1,666 patients who underwent fine needle aspiration for breast lumps, 4 developed pneumothorax as a complication. The incidence of this complication in our patients is 1:417. The clinical manifestations were immediate chest pain, shoulder pain and, occasionally, dyspnea that developed later. Observation is sufficient treatment in most patients, and rarely is drainage of the pneumothorax required.     

Contour path FDTD method for analysis of pyramidal horns withcomposite inner E-plane walls

The contour path finite-difference time-domain (FDTD) method is used for modeling pyramidal horn antennas with or without composite E-plane inner walls. To model the pyramidal horn surface, a locally distorted grid is used. Modified equations are obtained based on the locally distorted grid and the assumptions of the contour path method. The developed algorithm is validated by comparing computed antenna gain patterns, with and without the presence of composite material, with available measurements     

Early detection of ageing in solder joints through laser probe thermal analysis of the peltier effect

We have recently developed an optical contactless method for testing the quality of solder joints during accelerated thermal cycling ageing processes.¹ The method was based upon the measurement of the dynamic thermal behaviour of the joint to short bursts of Joule heating. It has proved to be efficient in revealing the formation of cracks at the lead-solder interface. We present a method to evaluate ageing at a much earlier stage in the cycling process. We have observed in earlier work,¹ that before cracks appear, structural changes occur in the solder at the lead-solder interface. The thermal response of the solder joint is recorded over time to a Peltier heat perturbation produced by flowing a current pulse through the interface where structural changes occur. The key point in this method is to discriminate the Peltier effect from the Joule thermal response because both effects generate heat. The variation of the early Peltier response in the thermal cycling ageing tests is seen as a quantitative signature of the structural changes in the lead-solder interface.