A Small Platform for Astrophysical Research Based on the UPM-Sat 1 Satellite of the Universidad Politécnica de Madrid

UPM-Sat 1 is a small scientific, in-orbit demonstration, educational satellite which has been designed, built, tested, integrated, launched and operated by a team of professors, students, and auxiliary personnel belonging to the Universidad Politécnica de Madrid (UPM). After completion of UPM-Sat 1 Mission a new small satellite, UPM-Sat 2, oriented to low-Earth-orbit scientific mission has been designed. In this paper the different subsystems of UPM-Sat 1 are described and the main characteristics of the second small satellite UPM-Sat 2 are outlined

On the galloping instability of two-dimensional bodies having elliptical cross sections.

Galloping, also known as Den Hartog instability, is the large amplitude, low frequency oscillation of a structure in the direction transverse to the mean wind direction. It normally appears in the case of bodies with small stiffness and structural damping, when they are placed in a flow provided the incident velocity is high enough. Galloping depends on the slope of the lift coefficient versus angle of attack curve, which must be negative. Generally speaking this implies that the body is stalled after boundary layer separation, which, as it is known in non-wedged bodies, is a Reynolds number dependent phenomenon. Wind tunnel experiments have been conducted aiming at establishing the characteristics of the galloping motion of elliptical cross-section bodies when subjected to a uniform flow, the angles of attack ranging from 0° to 90°. The results have been summarized in stability maps, both in the angle of attack versus relative thickness and in the angle of attack versus Reynolds number planes, where galloping instability regions are identified

Geothermometrical modelling applied to the CO2-rich thermal waters of the Lanjarón hydrothermal system (Granada, Spain)

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Microsatellite variation in Spanish Alano dogs

We have studied a sample of 35 spanish alano dogs in order to estimate the level of genetic variability that can be detected by using microsatellites and the efficiency of these genetic markers as tools for parentage testing in this canine population. We have used 4 microsatellites previously described in the literature. All of them were polymorphic, with an average number of 5 alleles/ locus and an average gene diversity (H) of 0,70 ± 0,06, similar to the figures reported in others breeds. Two of the microsatellites showed disa-greement with Hardy-Weinberg proportions, due to a deficit of heterozygotes. We have found in one of the microsatellites alleles that could be breed specific, as they have not been detected in other spanish breeds. The combined exclusion probability detected is higher than 90 percent, suggesting the possibility of using efficiently microsatellites in parentage testing in the spanish alano population.En una muestra de 35 alanos españoles se investigó la utilidad de los microsatélites para detectar variabilidad genética y para el control de paternidad. Los 4 microsatélites utilizados, descritos ya en la bibliografía, resultaron polimórficos, con un número medio de 5 alelos/ locus y una heterocigosis media (H), de 0,70 ± 0,06, similar a la de otras razas caninas. Se ha detectado una desviación del equilibrio Hardy-Weinberg para dos microsatélites debida a un déficit de heterocigotos. En un microsatélite se han detectado alelos inexistentes en otras razas españolas, por lo que podrían ser específicos de raza. La probabilidad acumulada de exclusión de paternidad es superior al 90 p.100, por lo que podrían ser eficaces para estas pruebas en alanos

Metodología de investigación de los yacimientos de pizarras para cubiertas

[Resumen] Se exponen .las bases metodológicas autores aplican a la investigación y de yacimientos de pizarras para cubiertas, tanto de su propia experiencia como de bibliografía disponible sobre el tema. Los factores que controlan la calidad de los yacimientos de dicha materia prima son de tres tipos: Litoestratigráficos, estructurales y metamórficos. Ellos se reflejan en una serie de parámetros que son los que habitua1ment e s e evalúan en e1 campo. La investigación utiliza técnicas geológicas básicas, adaptadas a las peculiaridades de la pizarra. Aquélla se lleva a cabo en tres fases. De cada una de las fases se presentan ejemplos. Se apuntan también algunas nuevas técnicas de investigación tomadas de la bibliografía, que podrían ser de aplicación en este campo.[Résumé] Il s'exposent les bases méthodologiques que 1es auteur s app1i quen t á 1I investigation et évaluation de gisements des ardoises pour couvertures, prisses autant de sa propre expérience que de la maigre bibliographie disponible sur le sujeto Les facteurs que controlent la qualité des gisements de la materie prime sont trois types: Litoestratiphiques, estructurales et metamórphiques. lIs se réfléchent sur une serp€ de parámetres que sont ceux que normalement s'evaluent sur le champ. L' investigation utilise les téc niques básiques, adaptées aux peculiarités de Celle-lá se mene á bien en trois phases. une des phases on presenten des exemples. On remarque aussi quelques nouvelles técniques 'investigation cherchées sur la bibliographie, qu'il pouvaient etre d'aplication sur ce champ

Small-signal modeling of phase-shifted full-bridge converter considering the delay associated to the leakage inductance

This paper demonstrates that in the Phase-Shifted Full-Bridge (PSFB) buck-derived converter, there is a random delay associated with the blanking time produced by the leakage inductance. This random delay predicts the additional phase drop that is present in the frequency response of the open-loop audio-susceptibility transfer function when the converter shows a significant blanking time. The existing models of the PSFB converter do not contemplate the delay and gain differences associated to voltage drop produced in the leakage inductor of the transformer. The small-signal model proposed in this paper is based on the combination of two types of analysis: the first analysis consists of obtaining a small-signal model using the average modeling technique and the second analysis consists of studying the natural response of the power converter. The dynamic modeling of the Phase-Shifted Full-Bridge converter, including the random delay, has been validated by simulations and experimental test.This research was funded by the European Regional Development Fund, the Ministry of Science, Innovation and Universities and the State Research Agency, grant number DPI2017-84572-C2-2-R

Self-sufficient asymmetric reduction of β-ketoesters catalysed by a novel and robust thermophilic alcohol dehydrogenase co-immobilised with NADH

β-Hydroxyesters are essential building blocks utilised by the pharmaceutical and food industries in the synthesis of functional products. Beyond the conventional production methods based on chemical catalysis or whole-cell synthesis, the asymmetric reduction of β-ketoesters with cell-free enzymes is gaining relevance. To this end, a novel thermophilic (S)-3-hydroxybutyryl-CoA dehydrogenase from Thermus thermophilus HB27 (Tt27-HBDH) has been expressed, purified and biochemically characterised, determining its substrate specificity towards β-ketoesters and its dependence on NADH as a cofactor. The immobilization of Tt27-HBDH on agarose macroporous beads and its subsequent coating with polyethyleneimine has been found the best strategy to increase the stability and workability of the heterogeneous biocatalyst. Furthermore, we have embedded NADH in the cationic layer attached to the porous surface of the carrier. Since Tt27-HBDH catalyses cofactor recycling through 2-propanol oxidation, we achieve a self-sufficient heterogeneous biocatalyst where NADH is available for the immobilised enzymes but its lixiviation to the reaction bulk is avoided. Taking advantage of the autofluorescence of NADH, we demonstrate the activity of the enzyme towards the immobilised cofactor through single-particle analysis. Finally, we tested the operational stability in the asymmetric reduction of β-ketoesters in batch, succeeding in the reuse of both the enzyme and the co-immobilised cofactor up to 10 reaction cycles

Nonlinear analysis of a simple model of temperature evolution in a satellite

We analyse a simple model of the heat transfer to and from a small satellite orbiting round a solar system planet. Our approach considers the satellite isothermal, with external heat input from the environment and from internal energy dissipation, and output to the environment as black-body radiation. The resulting nonlinear ordinary differential equation for the satellite's temperature is analysed by qualitative, perturbation and numerical methods, which show that the temperature approaches a periodic pattern (attracting limit cycle). This approach can occur in two ways, according to the values of the parameters: (i) a slow decay towards the limit cycle over a time longer than the period, or (ii) a fast decay towards the limit cycle over a time shorter than the period. In the first case, an exactly soluble average equation is valid. We discuss the consequences of our model for the thermal stability of satellites.Comment: 13 pages, 4 figures (5 EPS files

Anhydrite/aerogel composites for thermal insulation

High performance thermal insulating composite materials can be produced with mineral binders and hydrophobic aerogel particles through a hydrophilization process for the latter with surfactants. The present study is focused on the development of aerogel/calcium sulfate composites by the hydrophilization of hydrophobic silica aerogel particles through a polymer-based surfactant. Its effects on the microstructure and hydration degree are examined as well as their relation to the resulting mechanical and physical properties. Results show that composites with an around 60 % of aerogel by volume can achieve a thermal conductivity 35 %. Towards material optimization, a model for the calculation of thermal conductivity of composites and an equation for the compressive strength are proposed