663 research outputs found
Proyecto de diseño e instalación de riego en una parcela del T.M. de Becerril de Campos (Palencia)
No disponibleGrado en Ingeniería Agrícola y del Medio Rura
The localization of phonons in ion traps with controlled quantum disorder
We show that the vibrations of a chain of trapped ions offer an interesting route to explore the physics of disordered quantum systems. By preparing the internal state of the ions in a quantum superposition, we show how the local vibrational energy becomes a stochastic variable, its statistical properties inherited from the underlying quantum parallelism of the internal state. We describe a minimally perturbing measurement of the resonance fluorescence, which allows us to study effects such as Anderson localization without the need for ground-state cooling or individual addressing and thus paves the way for high-temperature ion experiments
Estudio del efecto del óxido en el comportamiento en rotura de la vaina de barra combustible
La capa exterior de óxido en la vaina de combustible nuclear es un factor clave en el estudio de su comportamiento en rotura. En esta ponencia se utiliza el ensayo de compresión diametral (RCT) para estudiar el comportamiento en rotura de vainas oxidadas. Para ello se prepararon muestras con una capa exterior de óxido de circonio de 85 µm de espesor y se sometieron a RCT a 20 y 135 ºC. El ensayo de compresión diametral ha demostrado ser muy sensible a la presencia de óxido en el exterior de la vaina para ambas temperatura
Esterification of Free Fatty Acids with Glycerol within the Biodiesel Production Framework
Companies in the field of the collection and treatment of waste cooking oils (WCO) for subsequent biodiesel production usually have to cope with high acidity oils, which cannot be directly transformed into fatty acid methyl esters due to soap production. Since glycerine is the main byproduct of biodiesel production, these high acidity oils could be esterified with the glycerine surplus to transform the free fatty acids (FFA) into triglycerides before performing the transesterification. In this work, commercial glycerol was esterified with commercial fatty acids and commercial fatty acid/lampante olive oil mixtures over tin (II) chloride. In the first set of experiments, the esterification of linoleic acid with glycerol excess from 20 to 80% molar over the stoichiometric was performed. From 20% glycerol excess, there was no improvement in FFA reduction. Using 20% glycerol excess, the performance of a biochar obtained from heavy metal-contaminated plant roots was compared to that of SnCl2. Then, the effect of the initial FFA content was assessed using different oleic acid/lampante olive oil mixtures. The results illustrated that glycerolysis was impeded at initial FFA contents lower than 10%. Finally, the glycerolysis of a WCO with 9.94% FFA was assayed, without success
Realineamiento por campo magnético en estructuras cilíndricas de cristal líquido nemático
En este artículo se presenta un análisis del realineamiento inducido por campos magnéticos aplicados sobre estructuras cilíndricas de cristal líquido nemático. Se analizan
las dos posibles configuraciones moleculares, homeotrópica y homogénea,con campos longitudinales y transversales aplicados a ellas. Los resultados más significativos
son la aparición de un campo umbral, para configuraciones homogéneas y campos transversales, y de un plano de moléculas que no sufren reorientación, para configuraciones homeotrópicas y campos transversales
Lambda = 3 mm line survey of nearby active galaxies
We used the IRAM 30m telescope to observe the frequency range [86-116]GHz
towards the central regions of the starburst galaxies M83, M82, and NGC253, the
AGNs M51, NGC1068, and NGC7469, and the ULIRGs Arp220 and Mrk231. Assuming LTE
conditions, we calculated the column densities of 27 molecules and 10
isotopologues. Among others, we report the first tentative detections of
CH3CHO, HNCO, and NS in M82 and, for the first time in the extragalactic
medium, HC5N in NGC253. Halpha recombination lines were only found in M82 and
NGC253. Vibrationally excited lines of HC3N were only detected in Arp220.
CH3CCH emission is only seen in the starburst-dominated galaxies. By comparison
of the fractional abundances among the galaxies, we looked for the molecules
that are best suited to characterise the chemistry of starbursts, AGNs and
ULIRGs, as well as the differences among galaxies within the same group.Comment: 24 pages, 6 figures, 12 tables. Accepted for publication in Astronomy
and Astrophysic
Nuevas técnicas metodologías para el fomento de habilidades transversales y transferencia del conocimiento en universitarios
Knowledge transference and its business potential are very much related to founders’ skills, and especially to the development of their transversal skills. Unfortunately, the time needid to achieve these skills spontaneously penalizes their possibilities. The implementation of pilot experiences in application of agile innovation methodologies such as "Lean Startup" and "Scrum" to real business projects during their incubation and acceleration process at the University of Seville has thrown interesting data about the best work dynamics during the process, with measurements of productivity, the "momentum" of the project, its "focus abilities" or qualitative assessments of those involved in the study. The results reveal a series of advantages and disadvantages derived from the application of these methodologies, which exert influence both on the individual performance and on the group of founders, that in general have turned out to be positive, since they allow to accelerate the maturation process to achieve the skills needed to increase survival ratios, or to conclude that it is not a viable project by making use of significantly less time and resources.La transferencia del conocimiento y su potencial empresarial están muy relacionadas con la capacidad del equipo promotor, y especialmente con el desarrollo de habilidades transversales. Por desgracia, el tiempo necesario para lograr estas habilidades de forma espontánea penaliza sus posibilidades. La puesta en marcha de experiencias piloto de aplicación de metodologías ágiles de innovación como “Lean Startup” y “Scrum” a proyectos empresariales reales durante su proceso de incubación y aceleración en la Universidad de Sevilla ha permitido obtener datos interesantes acerca de la dinámica de trabajo individual y grupal registrada durante el proceso, con mediciones de la productividad, el “nivel de inercia” del proyecto, su “capacidad de foco” o valoraciones cualitativas de los implicados en el estudio. Los resultados descubren una serie de ventajas e inconvenientes derivados de la aplicación de estas metodologías, que ejercen influencia tanto en el desempeño individual como del conjunto de fundadores del proyecto, y en líneas generales han resultado ser positivos, ya que permiten acelerar el proceso de maduración personal hacia la consecución de las habilidades necesarias para incrementar la supervivencia del proyecto, o bien para concluir que no es viable haciendo uso de una cantidad significativamente inferior de tiempo y recursos
- …