The Influence of the Silicone Carbide Content and Type on the Microstructure and the Flaw Level of Silica Ceramics

Comprehensive studies of the flaw level and some structural characteristics of a composite ceramic material based on Karakeche clay (Kyrgyzstan) are carried out for a range of thermoactivation regimes and impurity contents of silicone carbides of various types.     

Statistical model of an undermoded reverberation chamber

Weibull distribution is adopted to model the electric field component of a Reverberation Chamber (RC). Its first property is to include the asymptotic laws, such as Rayleigh and exponential, and its main advantage lies in the fact that the Weibull shape parameter enables a model of the departure from overmoded to undermoded RC regime. Applications are given, such as an RC modal finite element modeling and a Monte Carlo simulation: they prove that the Weibull two-parameter distribution correctly models the quality factor influence. Moreover, the relevance of the use of this extreme value distribution is illustrated.     

Temperature Dependence of the Magnetic Properties of Amorphous Fe-Me-Si-B Alloys

Alloying of amorphous Fe-Me-Si-B metallic compositions with nickel and molybdenum results in a decrease in the values of saturation magnetization in fields with a magnetic intensity of 0.72 MA/m. The same alloying additions decrease the temperature of formation of new magnetic Fe₃B-type phases, which are stable up to 873 ± 5 K.     

Survey of nitrate and nitrite contents of vegetables grown in Korea.

A scientific basis for the evaluation of the risk to public health arising from excessive dietary intake of nitrate in Korea is provided. The nitrate () and nitrite () contents of various vegetables (Chinese cabbage, radish, lettuce, spinach, soybean sprouts, onion, pumpkin, green onion, cucumber, potato, carrot, garlic, green pepper, cabbage and Allium tuberosum Roth known as Crown daisy) are reported. Six hundred samples of 15 vegetables cultivated during different seasons were analysed for nitrate and nitrite by ion chromatography and ultraviolet spectrophotometry, respectively. No significant variance in nitrate levels was found for most vegetables cultivated during the summer and winter harvests. The mean nitrates level was higher in A. tuberosum Roth (5150 mg kg(-1)) and spinach (4259 mg kg(-1)), intermediate in radish (1878 mg kg(-1)) and Chinese cabbage (1740 mg kg(-1)), and lower in onion (23 mg kg(-1)), soybean sprouts (56 mg kg(-1)) and green pepper (76 mg kg(-1)) compared with those in other vegetables. The average nitrite contents in various vegetables were about 0.6 mg kg(-1), and the values were not significantly different among most vegetables. It was observed that nitrate contents in vegetables varied depending on the type of vegetables and were similar to those in vegetables grown in other countries. From the results of our studies and other information from foreign sources, it can be concluded that it is not necessary to establish limits of nitrates contents of vegetables cultivated in Korea due to the co-presence of beneficial elements such as ascorbic acid and alpha-tocopherol which are known to inhibit the formation of nitrosamine.     

Stress-Corrosion Fracture of 12Kh18AG18Sh Steel in Chloride-Containing Media with Copper Cations

We studied the corrosion and corrosion-mechanical resistance of new austenitic high-nitrogen 12Kh18AG18Sh steel for the retaining rings of turbogenerators in aqueous solutions containing chlorides and copper (II) cations. A significant decrease in the corrosion resistance of this steel (P constitutes 0.52–14.50 mm/year) and in its resistance to corrosion cracking and corrosion-fatigue fracture in CuCl₂ solutions was established. We also calculated the coefficients of linear parts of the kinetic diagrams of fatigue fracture of the steel under study in air with a humidity of 40% and in 22% NaCl and CuCl₂ solutions.     

Eye tracking — A new interface for visual exploration

Eye-tracking technology offers a natural and immediate way of communicating human intentions to a computer. Eye movements reflect interests and may be analysed to drive computer functionality in games, image and video search, and other visual tasks. This paper examines current eye tracking technologies and their applications. Experiments are described that show that target images can be identified more rapidly by eye tracking than using a mouse interface. Further results show that an eye-tracking technology provides an efficient interface for locating images in a large database. Finally the paper speculates about how the technology may enter the mass market as costs decrease.     

Interaction between monitorability indicators and operational characteristics of communications equipment

This article considers the influence of changes in monitorability indicators on the operational characteristics of communications equipment. For indicators of monitorability we take the depth of defect search, failure localizability, overhead, and others. Among the operational characteristics, those considered include time to repair, probability of undetected failure, probability of failure-free operation, etc. The results obtained make it possible to estimate, during the design phase, the influence of changes in monitorability factors on the operational characteristics of equipment and to make selections that meet given requirements. Translated from Izmeritel'naya Tekhnika, No. 6, pp. 23–26, June, 1996.