Analytical Expressions for Radiative Opacities of Low Z Plasmas

In this work we obtain analytical expressions for the radiative opacity of several low Z plasmas (He, Li, Be, and B) in a wide range of temperatures and densities. These formulas are obtained by fitting the proposed expression to mean opacities data calculated by using the code ABAKO/ RAPCAL. This code computes the radiative properties of plasmas, both in LTE and NLTE conditions, under the detailed-level-accounting approach. It has been successfully validated in the range of interest in previous works

the demand of mineral resources

info:eu-repo/semantics/draf

the demand of mineral resources

info:eu-repo/semantics/draf

Contribución al conocimiento florístico de las Sierras de Algeciras (Cádiz, España)

Se relaciona un total de 745 taxones para 1as sierras cercanas a la población de Algeciras (Cádiz), de las que se indica su distribución en la zona, abundancia y época de floración.A number of 745 taxa are indicated from mountains near Algeciras (Cádiz), with distribution in this area, abundance and flowering date

El departamento de orientación en la universidad. el caso de la universitat Jaume I

La importancia del Servicio de Orientación Universitario en nuestro país viene actualmente avalado por su implicación para dar respuesta a lo planteado en el estatuto del Estudiante (Real Decreto 1791/2010 de 30 de diciembre), ya que en el capítulo XV “Atención al universitario”, en su artículo 65 “Servicio de atención al estudiante”, se hace mención explícita a dicho Servicio. A nivel Europeo, se considera que los Servicios de Orientación son muy importantes como apoyo a los estudiantes, especialmente para el buen desarrollo del EEES, con el fin de prestar apoyo en los aspectos académicos, toma de decisiones, itinerarios y salidas profesionales. Los presupuestos teóricos que deberían sustentar la actuación de todo Departamento de Orientación Universitario podrían concretarse –entre otros- en: a) Basarse en la línea de Life Span descrita por Super; b) Establecer una coordinación con los asesores de otros niveles educativos; c) Dinamizar la transición de Secundaria a la Universidad y de ésta al mundo laboral. Prestando atención a la diversidad; d) Estar regido por especialistas. En cuanto al Departamento de Orientación de la Universitat JAUME I (USE-UJI), se organiza en las siguientes áreas: Información, Profesorado, Orientación, Atención a la Diversidad. En cuanto a la evaluación hemos seguido el modelo de Viera y el de la Agencia americana Nortwest. El resultado ha sido muy positivo. En definitiva, y teniendo en cuenta diversos informes de la Unión Europea, destacamos que el Servicio de Orientación en la universidad contemple una serie de directrices, tales como: 1) Exigir a los profesionales que tengan las competencias necesarias para desempeñar las tareas de orientación; 2) Considerar qué normas se podrían utilizar para acreditar a los servicios de orientación; 3) Mejorar la calidad de los servicios al exigir niveles más altos en la formación inicial y permanente del personal de los servicios de orientación

Bio-Lubricants production from fish oil residue by transesterification with trimethylolpropane

The fatty acid ethyl esters mixture, a fish oil residue obtained after the extraction of omega-3 polyunsaturated fatty esters, has been converted into mixtures of mono-, di-, and triesters of trimethylolpropane by transesterification at 100-140¿°C under vacuum with sodium ethoxide as catalyst. This method has shown to be more efficient than the enzymatic transesterification using commercially available lipases. The crude reaction mixture (84% conversion of ethyl esters), enriched in trimethylolpropane triesters (96% selectivity) was characterized and its properties compared with those of the starting ethyl esters mixture and the trimethylolpropane esters obtained from vegetal sources

Soft Tissue Behavior During Limb Lengthening: An Experimental Study in Lambs

The effect of femoral elongation on skeletal muscle, nerves, and vessels was studied. Three groups of five lambs were used. After the intervention, the animals were killed at 2, 3, and 4 months. A left femoral elongation of 6 cm was practiced on all of them by means of callotasis, with a distraction rate of 0.5 mm every 12 hours. The femoral elongation process was evaluated by monthly x-ray films. The nucleic acid and protein levels in the muscular tissue were quantified at the level of the elongation focus and in the control extremity. The motor conduction velocity of the sciatic nerve was measured in both posterior limbs before the intervention and immediately before the lambs were killed. The arterial blood flow of both subsequent extremities was measured at the moment of death. A histological study of quadriceps muscle, sciatic nerves, artery, and subsequent femoral vein were examined histologically at the level of the elongation focus of both extremities. After elongation, no significant differences were observed in the muscle protein and nucleic acid levels with respect to the control extremity. No significant changes of the nerve conduction velocity were observed in any animal among the different groups. The arterial blood flow of the elongated extremity showed a progressive increase, reaching its maximum value 1 month after the distraction had terminated, with subsequent normalization. This increase of the blood flow was also observed in the control extremity, suggesting a possible systemic effect. The histological study revealed a comparative thickening of the endomysium and perimysium in the elongated muscle tissue, present at the end of the distraction and which was later normalized. No histological changes of the nerve stems undergoing distraction were observed either. During elongation, the arteries showed minimal histological changes. On the other hand, the veins showed areas of endothelial damage accompanied by thrombosis phenomena, especially at the end of the distraction period. The vascular morphology presented progressive normalization after the distraction phase

General dissipation coefficient in low-temperature warm inflation

In generic particle physics models, the inflaton field is coupled to other bosonic and fermionic fields that acquire large masses during inflation and may decay into light degrees of freedom. This leads to dissipative effects that modify the inflationary dynamics and may generate a nearly-thermal radiation bath, such that inflation occurs in a warm rather than supercooled environment. In this work, we perform a numerical computation and obtain expressions for the associated dissipation coefficient in supersymmetric models, focusing on the regime where the radiation temperature is below the heavy mass threshold. The dissipation coefficient receives contributions from the decay of both on-shell and off-shell degrees of freedom, which are dominant for small and large couplings, respectively, taking into account the light field multiplicities. In particular, we find that the contribution from on-shell decays, although Boltzmann-suppressed, can be much larger than that of virtual modes, which is bounded by the validity of a perturbative analysis. This result opens up new possibilities for realizations of warm inflation in supersymmetric field theories.Comment: 25 pages, 13 figures; revised version with new results added; published in JCA

Optimisation of post-drawing treatments by means of neutron diffraction

The mechanical properties and the durability of cold-drawn eutectoid wires (especially in aggressive environments) are influenced by the residual stresses generated during the drawing process. Steelmakers have devised procedures (thermomechanical treatments after drawing) attempting to relieve them in order to improve wire performance. In thiswork neutron diffraction measurements have been used to ascertain the role of temperature and applied force – during post-drawing treatments – on the residual stresses of five rod batches with different treatments. The results show that conventional thermomechanical treatments are successful in relieving the residual stresses created by cold-drawing, although these procedures can be improved by changing the temperature or the stretching force. Knowledge of the residual stress profiles after these changes is a useful tool to improve the thermomechanical treatments instead of the empirical procedures used currently

Optimization of a new Ni-free Ti alloy for applications in the implant field

Three new Ni-free Ti alloys, Ti-16.2Hf-24.8Nb-1Zr, Ti-5.2Hf-31.2Nb-0.4Zr and Ti-16Hf-36.2Nb-1Zr (wt%), were designed and produced in order to obtain shape memory and/or low elastic modulus materials in order to avoid stress shielding and to enhance bone regeneration in the load transfer implant field. The alloys were microstructurally and mechanically characterized, cytotoxicity was evaluated using MG63 osteoblast-like cells. The elastic modulus of the new alloys (between 67-90 GPa) are smaller than those of the commercial alloys employed for implantation. The lowest elastic modulus alloy, Ti-16.2Hf-24.8Nb-1Zr (wt %), with 67.5 GPa, was optimized by cold work in order to determine the key factor that promotes the desired shape memory properties and/or low elastic modulus. A higher proportion of martensite was observed by optical and electron transmission microscopy in the low cold work samples compared to the quenched alloy. The elastic modulus for each cold work condition was evaluated by nanoindentation tests using a spherical tip. The elastic modulus decreases when increasing the cold work level. The lowest value corresponds to the 99% cold work condition, with 44 GPa, closer to that of cortical bone and smaller than the quenched alloy (67.5 GPa).Tres nuevas aleaciones de Ti libres de Ni, Ti-16.2Hf-24.8Nb-1Zr, Ti-5.2Hf-31.2Nb-0.4Zr y Ti-16Hf-36.2Nb-1Zr, porcentajes en peso, fueron diseñadas y fabricadas con el fin de obtener memoria de forma y/o bajo módulo elástico con el objetivo de evitar el apantallamiento de cargas y mejorar la regeneración ósea en el campo de la implantología de transferencia de carga. Las aleaciones fueron caracterizadas microestructural y mecánicamente y la citotoxicidad fue evaluada utilizando osteoblastos MG63. El módulo elástico de las nuevas aleaciones (entre 67-90 GPa) es menor que el de las aleaciones comerciales utilizadas en implantología. El menor módulo elástico corresponde a la aleación Ti-16.2Hf-24.8Nb-1Zr, con 67.5 GPa y fue optimizado mediante trabajo en frío con el objetivo de determinar el factor responsable de la obtención de las propiedades deseadas de bajo módulo elástico y/o memoria de forma. Una mayor proporción de martensita fue observada por microscopía óptica y microscopía electrónica de transmisión en las muestras con bajo porcentaje de trabajo en frío en comparación con la muestra templada. El módulo elástico correspondiente a cada condición de trabajo en frío fue evaluado mediante nanoindentación con punta esférica. El módulo elástico disminuye al aumentar el porcentaje de trabajo en frío. El menor valor corresponde a la condición de 95% de trabajo en frío, con 44 GPa, valor cercano al del hueso cortical y menor que el del material templado (67.5 GPa).Peer Reviewe