Calculation of the effective ionic radii of Al1+ and Al2+, the standard enthalpies of formation of the crystalline oxides Al2O, AlO, and Al3O4, and the enthalpies of their crystal lattices

The sizes of particles (ions and their associations) that participate in processes related to heat and mass transfer and electrotransport in condensed matter, as well as the interaction of the particles, are of importance. The effective radii of the Al¹⁺ and Al²⁺ ions are calculated in accordance with models proposed earlier. The standard enthalpies of formation of the Al₂O, AlO, and Al₃O₄ oxides and their crystal lattices are determined using these effective ionic radii. The coincidence of the parameters that have been calculated using independent models and initial data for different oxides indicates that these models are reliable and can be used for predictions. The calculated data bring the crystal structure parameters and the thermochemical constants of the oxides into agreement. Original Russian Text ? A.G. Ryabukhin, V.E. Roshin, A.V. Roshin, 2007, published in Metally, 2007, No. 2, pp. 11–18.     

Superconductivity in hcp Li at high pressure

Recent experimental observations show that metallic lithium becomes a superconductor at high pressure. Here the theoretically calculated band structure as well as the superconducting transition temperature for this metal at 247 kbar pressure are reported. The band structure was obtained using the APW method. The superconducting transition temperature determined using the band structure results agrees fairly well with that measured experimentally.     

Probability method of controlling the consumption of safe life of agte parts by the limiting temperature criterion

A method is proposed for predicting the residual safe life of aircraft engine parts. It facilitates limiting temperature-based control of the depletion, during operation, of durability reserves set when designing these parts. The method is based on probability comparison of in-flight temperature maxima of the parts with limiting temperatures of their materials. The method of least squares is recommended for evaluating the parameters of distributions of in-flight temperature maxima and limiting temperatures that are described by extreme type laws. A series of integral relationships necessitating the use of numerical methods are obtained for the residual gamma-percent safe life of the parts.Translated from Problemy Prochnosti, No. 10, pp. 54–58, October, 1991.     

Microstructure of Selected Binary Food Powder Mixtures

Binary mixtures of sugar, citric acid, malic acid, soy protein and starch, after exposure to various relative humidities, were analyzed by Scanning Electron Microscopy (SEM). It is shown that depending on interparticle surfaceaffinity, concentration and relative humidity, the mixtures could be random, partially random, ordered or partially ordered. The type of bridging, between the aggregated particles depended on their chemical species and the availability of surface moisture.     

Effects of Vacuum Hydration on the Incidence of Splits in Canned Kidney Beans (Phaseolus vulgaris)

Dry red kidney beans were canned using two different pretreatments: soaking for 12 hr at 20°C, and vacuum hydration for 5 min followed by soaking for 2 hr at temperatures from 45-59.1°C. Samples were then packed, processed to commercial sterility, and tested for percentage of split beans after processing. Vacuum hydration pretreatments greatly decreased the incidence and severity of splitting in the canned product and accelerated water uptake while retaining the same moisture content after soaking as the conventional soak treatment. Vacuum-hydrated beans gained less moisture during retorting than conventionally treated samples.     

The actual nutrition of the rural population of the Georgian SSR

A study was made of the factual nutrition of the rural population living in 7 regions of the Georgian SSR with different climatogeographic conditions and different working and living routines. The data obtained point to the improvement of the nutrition of the population as compared with preceding years. The caloricity of the average annual daily diet of the rural population covers energy expenditures. However, it is marked by the predominance of carbohydrates. In spite of the fact that the quota of proteins in the diet has increased, the consumption of animal proteins remains at a low level as is the use of vegetable fats. The diet of the population of all the regions under study was discovered to contain excess phosphorus and magnesium, but little ascorbic acid. Meanwhile the use of thiamine and riboflavin was established to be within normal physiological requirements.     

Oxygen consumption by portal-drained viscera of cattle: comparison of analytical methods and relationship to whole body oxygen consumption

Two experiments were conducted to compare methods of determining oxygen consumption by portal-drained viscera and to relate this consumption to total oxygen consumption by lactating dairy cows. Oxygen consumption was the product of portal blood flow (determined by dilution of dye infused into a mesenteric vein) and portal-arterial concentration differences of oxygen. In Experiment 1, portal-arterial concentrations of oxygen were determined in samples from three cows using equations based on blood pH, hemoglobin, partial pressure of carbon dioxide, and partial pressure of oxygen (method 1) or by direct oxygen determination with an oximeter (method 2). Overall, there were no differences in oxygen concentrations or oxygen consumption by portal-drained viscera between methods. In Experiment 2, oxygen consumption by portal-drained viscera (method 2) and total oxygen consumption were measured in two lactating cows. Oxygen consumption by portal-drained viscera accounted for 18% of total oxygen consumption.     

The effects of stress and crack morphology on time-of-flight diffraction signals

A model based on the theory of infinite contacting surfaces is used to analyse the transmission and reflection of ultrasound at tight fatigue cracks under compressive stress. The model developed is valid for both compression and shear (SV) waves incident at arbitrary angles on a fatigue crack and includes mode conversion effects. In discussing diffraction of ultrasound by the tips of finite length fatigue cracks, we associate the amplitude of the diffracted signal with the strength of the signal reflected from cracks of infinite extent. Thus we allow all the energy transmitted by the tight crack to play no part in the diffraction process. Comparison is made with experiments carried out at Harwell and we conclude that, for these particular experiments, the cracks are fully open when subjected to about 88 MPa of tension, and that the experimental results are consistent with a root mean square deviation from flatness of the crack faces of about 1·5 μm. This is in broad agreement with the actual crack profile when a sampling length of about 30 μm is used. Using these values the theory and experiment show excellent agreement to within 2 dB over the whole applied stress range. The results show, for example, a diffraction signal decreased by a maximum of about 13 dB when the applied compressive load corresponds to 70% of the maximum load used during crack growth. Similar conclusions are also drawn for conventional pulse-echo inspection, whereas Tandem suffers a greater reduction in signal strength due to the usually lower frequency.     

Automated fluorimetry in quality control of pasteurized and ultra-high temperature-treated starch soup

Automated monitoring of the microbiological quality of heat-processed foods by the resazurin reduction test was applied to microtitration plate incubator-fluorimeter technology. The appearance and disappearance of the fluorescing peak of resorufin was monitored on microtitration trays. Pasteurized or ultra-high temperature-treated starch-based soup was used as the model food system. Bacillus subtilis spores (ultra-high temperature treatment) and vegetative cells of Enterococcus faecalis (pasteurization) were inoculated into the soup before the heat treatment at levels which resulted in some survival. The timing of appearance of maximum fluorescence correlated with the number of bacteria in pre-incubated samples. Automated resazurin-reduction fluorimetry was compared with conventional plating, turbidometry and microcolony count by the direct epifluorescent filter technique. The results of the resazurin test correlated well with those of all the other methods tested. Fluorimetry had the advantage that the results could be read within 1–5h and the reproducibility was superior to the other methods.