[en] The evaporation of 90 octane gasoline in simulated spills on a sea surface or beach sand with different textures was studied. The effects of solar radiation, temperature, air velocity, and sand textures were measured and the variation in the evaporated fraction as a function of time, its diffusivity, and its density in discharge were determined. The diffusion of volatile components in the remaining mixture as a function of time during the evaporation process was calculated using the equation of unsteady-state molecular transport. An equation was found which correlated the fraction of evaporated mass to elapsed time. A parameter that measured the level of evaporation resistance was found to increase in value with decreasing sand-particle size. The presence of sand was found to slow down the evaporation process. 4 refs., 9 figs., 6 tabs

[en] The oil tanker Aegean Sea spilled oil when it grounded during severe storm conditions near La Coruna, Spain. Much of the oil burned after an explosion was caused by the hull breaking apart. Oil which contaminated several beaches was affected by both combustion and weathering. Experiments were conducted on oil sampled from the beaches to investigate dispersion of the oil using Beep Enersperse 1990 at different shaking speeds. Biodegradation experiments were also conducted in the presence of Beep Enersperse 1990 but with seawater absent. Although emulsification of the burnt and weathered oil was very difficult, good dispersion and biodegradation were obtained. After 42 d in a stirred reactor, biodegradation of the oil reached at least 80%. 3 refs., 3 figs., 4 tabs

[en] The work shows the energy and exergy evaluation of the combined cycle Energas Boca de Jaruco, which consists of five gas turbines 30 MWh five heat recovery steam OTSGs type and a steam turbine of 150 MW. This evaluation is performed without additional burning and for different percentages of utilization of these burners. The results allow to have a criterion of the efficiency of the system with and without supplementary burned, which can define strategies most appropriate system operation. (full text)

No abstract available

[en] The hypoattenuation of the basal ganglia is an uncommon radiological finding that suggests a metabolic or hypoxic disorder. We report a case of propionic acidemia in a five-year-old boy, presenting as a symmetric hypoattenuation of the basal neclei. We discuss this and other causes of this radiological finding, as well as the possible mechanism and underlying pathology. (Author) 17 refs

[en] Published in summary form only

[en] TlBa₂CaCu₂O₇ (Tl-1212) superconducting films 5000--6000 A thick have been grown on LaAlO₃ (100) substrates using oxide precursors in a closed two-zone thallination furnace. Tl-1212 films can be grown with transition temperatures ∼100 K, and critical current densities measured by magnetization of J_cm(5 K)>10⁷ A/cm² and J_cm(77 K)>10⁵ A/cm². Processing conditions, substrate temperatures and Tl-oxide source temperatures are found which result in smooth, nearly phase-pure Tl-1212 films. Variations in the respective temperature ramps of the Tl-oxide zone and the substrate zone can greatly influence resulting film properties such as microstructure, morphology, superconducting transition temperature, and critical current density. copyright 1995 American Institute of Physics

[en] The superconducting properties of TlBa₂CaCu₂O_7+δ(Tl-1212) films are greatly enhanced by annealing in unreactive ambients such as nitrogen at temperatures ranging from T_a=250--600 degree C. The transition temperature, T_c, of these Tl-1212 films as-grown in oxygen is 70 K. Annealing for 1 h at 250 degree C elevates T_c above 90 K. T_c further increases and sharpens for T_a=600 degree C. In addition, subtle changes occur in the microstructure correlating with improved critical current density. These results indicate that Tl-1212 films may be of greater relevance for electronics applications than previously believed. copyright 1995 American Institute of Physics

[en] We develop a shell model (SM) for magnesium hydride with interatomic potentials and anisotropic core-shell interactions. The model is fitted to measured Raman modes and ab initio results that we obtain for the phonons at the Γ point. We achieve a very good agreement for the Raman and silent phonons, while the infrared-active modes are less accurately described. Using the developed SM, we have computed the phonon dispersion throughout the Brillouin zone (BZ), which turns out to be in very good agreement with previous first-principles results. The SM partial phonon density of states due to hydrogen shows very good agreement with the experimental one. The temperature dependence of the specific heat is also calculated and shows good accordance with measurements

[en] The most common cardiac injuries in the United States are blunt trauma from motor vehicle accidents or low-velocity trauma from stabbings. During military conflict, high-velocity injuries, including gunshot wounds (GSW) and fragment injury from improvised explosive devices (IED), are relatively more common. This is a retrospective review of cases with high-velocity penetrating injury and suspected myocardial involvement during a 6-month period in Baghdad, Iraq, at a United States Army hospital during Operation Iraqi Freedom. Eleven cases survived to admission (GSW in 5, IED in 6). The mean age of the all-male cohort was 27 years (range, 3-54 years). Eight of the 11 patients (73%) were victims of polytrauma. The entrance involved the right ventricle (n=3), right atrium (n=2), left ventricle (n=1), or mediastinum and pericardial reflections (n=5). Echocardiography was performed in all 11 patients. In 7 patients, no foreign body was identifiable, and in 2 patients the foreign body was identified within the pericardial fat pad. Three patients were identified as having a suspected ventricular septal defect, ranging in size from 2 to 8 mm. The most common electrocardiographic abnormality was atrioventricular block and right bundle branch block. In 4 patients, the management of the chest injury was nonsurgical, and in 1 patient the treatment was a chest tube only. Four of the patients underwent median sternotomy, 1 underwent emergent lateral thoracotomy, and 1 underwent an infradiaphragmatic approach. This case series is too small to draw definitive conclusions; however, a multidisciplinary approach to high-velocity injuries with potential for cardiac involvement augments preoperative assessment for myocardial injury and may allow selective nonoperative management. (author)