Study of the reduction of UO2 by magnesium or calcium dissolved in molten chlorides

The reduction of solid UO₂ to uranium by magnesium or calcium dissolved in their molten chlorides has been studied. The rate of reduction per unit area of UO₂ surface, at constant temperature and concentration of reductant in the molten chloride, was found to increase with time to a constant value. The rate of reduction per unit area was observed to be proportional to the concentration of reductant in the molten salt. The small increase observed in the reaction rate over the temperature range 750° to 850°C, suggests that the reduction is controlled by transport of the reductant to the reaction site. Solidified salt, containing UO₂ pellets which had been partially reduced, was sectioned, polished, and examined microscopically. The products of the reduction reaction form concentric layers around the UO₂ pellets. Layers of metallic uranium and oxide containing small amounts of dispersed salt alternated with layers of salt containing small amounts of metallic uranium and oxide. The layers ruptured, presumably because the volume of the products, uranium and oxide, is greater than the volume of the UO₂. Therefore, an impervious layer did not form on the oxide surface to inhibit the reduction reaction.     

Nutritional and antioxidant status of an institutionalized elderly group in Murcia (Spain)

The aging of the population is giving rise to a large number of studies aimed at improving the quality of life, considering diet as a major contributing factor in this life stage. The objectives of the present study were to evaluate the nutritional status of a group of institutionalized elderly in Murcia, Spain, and to relate the diet to anthropometric and biochemical indices, paying special attention to total antioxidant status. The dietary evaluation showed excessive intakes of proteins and lipids, and deficiencies in those of carbohydrates, dietary fiber, zinc, iodine and vitamins A, E and D. The high proportion of overweight observed were not significantly correlated to the energy intakes. Although total plasma antioxidant status was low (0.62 mM eq Trolox and 0.98 mM eq Fe(II)) compared with reference values, estimated oxidative risk in this group of elderly was low according to plasma levels of vitamins C, A & E.     

Adaptability of sweet corn ears to a frozen process

The effects of frozen condition on the quality of three sweet corn ears (2038, 2010, 2004) and the pattern (Bonanza), were evaluated. Biometrics characteristics like ear size, ear diameter, row and kernel deep were measured as well as chemical and physical measurement in fresh and frozen states. The corn ears were frozen at -95 degrees C by 7 minutes. The yield and stability of the frozen ears were evaluated at 45 and 90 days of frozen storage (-18 degrees C). The average commercial yield as frozen corn ear for all the hybrids was 54.2%. The industry has a similar value range of 48% to 54%. The ear size average was 21.57 cm, row number was 15, ear diameter 45.54 mm and the kernel corn deep was 8.57 mm. All these measurements were found not different from commercial values found for the industry. All corn samples evaluated showed good stability despites the frozen processing and storage. Hybrid 2038 ranked higher in quality.     

Using <Superscript>1</Superscript>H and <Superscript>13</Superscript>C NMR techniques and artificial neural networks to detect the adulteration of olive oil with hazelnut oil

The lack of any official analytical method to detect the adulteration of olive oil with a low percentage of hazelnut oil is explained by the similarities in the chemical compositions of both kinds of oils. To counter this problem, an artificial neural network based on ¹H-NMR and ¹³C-NMR data has been developed to detect olive oil adulteration, and the results from this ANN are presented here. A training set consisting of hazelnut oils, pure olive oils, and olive oils blended with 2–20% hazelnut oils was used to design and train a multilayer perceptron with 100% correct classifications. This mathematical model was also validated using an external validation set of blend samples (3–15%) and genuine samples. The detection limit of the model was around 8%.     

W-CDMA Uplink Capacity and Interference Statistics of a Long Tunnel Cigar-shaped Microcells Using the Hybrid Model of Propagation with Imperfect Power Control

The uplink capacity and the interference statistics (mean and variance) of the sectors of the cigar-shaped W-CDMA microcell are studied. A model with eighteen sectors is used to analyze the uplink. The microcells are assumed to exist in a long tunnel with at least nine base stations. The hybrid model of propagation is used in the calculations. The capacity and the interference statistics of the sectors are studied in terms of the most important parameters: sector radius, specific attenuation factor, antenna sidelobe levels, bend losses and the power control standard deviation error.     

Cognitive abilities in driving: differences between normal and hazardous situations

This study investigated the relationship between cognitive abilities and driving behaviour in situations of normal driving and hazardous driving. For driving behaviour, driving component skills were measured from two different types of driving situations such as normal driving situations and hazardous driving situations. Normal driving skills were evaluated through an on-street driving test, where search, speed control, and direction control were considered as driving component skills. Hazardous driving component skills were evaluated using a standardized video driving paradigm. Component skills that were evaluated in this paradigm were search, identify, predict, decide, and execute. A battery of predictive tests was administered to the participants. Forty-two students from high schools participated in this study. Analysis of multiple regression implied that the measure of dynamic visual signal perception introduced to this study could be used as a predictor of driving performance for both situations. Driving component skills showed different effects between normal situations and hazardous situations.     

Surface-enhanced vibrational microspectroscopy of fulvic acid micelles

Micro-Raman spectroscopy, infrared absorption microspectroscopy, and AFM images of nano- or microsized micelles formed by fulvic acid (FA) solutions, prepared at different pHs, and cast on glass slides or gold island films, are reported. FA films cast on gold islands are characterized by surface-enhanced infrared absorption (SEIRA), surface-enhanced infrared reflection absorption, and surface-enhanced Raman scattering (SERS). Based on spectral evidence, it is expected that the chemisorption of FA on gold island films takes place through thiol groups, which become more active as pH increases. The SEIRA spectra of these films show increased peak intensity, as well as improved band resolution. Microspectroscopy SERS studies show that, at pH 5, FA form small aggregates on gold surfaces. At pH 8, FA tends to expand due to electrostatic repulsion, giving rise to a fractal surface composed of different domains. SERS studies of these domains reveal that the most polar molecules are located on the external faces. At pH 11, fractal conformations are even more pronounced and give rise to radial patterned structures. At this pH, the position of fulvic acid molecules in the fractal micelles is the same as observed at pH 8. In this way, SERS can be viewed as a powerful tool for the analysis of the composition, apparent contribution of the surface functional groups of FA films, and the FA building blocks (i.e., catechol, gallic, salicylic, or ftalic acids) in the structures of these materials.     

On the graphical analysis of the electronic structure of ferromagnetic clusters of medium size

In a previous work, a theoretical approach, suitable to describe systems having a large number of fermions, was proposed, and results for ferromagnetic surface clusters of medium size (100-1000 atoms) were presented. The aim of the present contribution is to complete this previous work. Several significant theoretical and technical details, omitted previously, are provided here. The obtained spin orbitals are analyzed, by studying their symmetry, energy, and d contribution properties.     

Analog Adaptive Median Filters

The implementation of analog adaptive median filters for image processing is discussed. The adaptive median filter is based on transconductance comparators, whose saturation current is adapted to act as a local weight operator. Transistor level simulations have shown excellent results in removing incidence noise. A 249 × 209 pixel image, corrupted with 35% salt and pepper noise, is used to test the adaptive median filter. All the simulations were made using BSIM3's level 49 model and 1.2 m MOSIS technology parameters.