Simulation and design of a three-stage metal hydride hydrogen compressor based on experimental thermodynamic data

Los investigadores de la UAM pertenecen al MIRE-GroupA semi-empirical method was developed to design a three stage Metal Hydride Hydrogen Compressor (MHHC) through the determination of thermodynamic properties of several hydrides. As a first step, three AB2-type alloys that satisfy operation conditions were selected from published thermodynamic data entailing over 200 single plateau hydrides. These alloys were synthetized by arc melting and characterized by X-Ray Powder Diffraction (XRPD), Scanning Electron Microscopy (SEM) and Energy Dispersion X-ray spectroscopy (EDX). Absorption and desorption Pressure-composition-Isotherms (P-c-I) were determined between 23 and 80 C to characterize their thermodynamic properties. Subsequently, an algorithm that uses these experimental data and a real equation of state for gaseous H2 was implemented to simulate the volume, alloy mass, pressure and temperature of operation for each compressor stage, while optimizing the compression ratio and total number of compressed H2 moles. Optimal desorption temperatures for the three stages were identified within the range of 110e132 C. A system compression ratio (CR) of 92 was achieved. The number of H2 moles compressed, the alloy mass and volume of each stage depend linearly on the volume of the external tank in which the hydrogen is delivere

Variability of taurine concentrations in Mytilus galloprovincialis as a function of body size and specific tissue

7 páginas, 5 figurasVariability of taurine (2-aminoethane sulfonic acid) was studied as afunction of size in the mussel Mytilus galloprovincialis and tissue specificity. Isometric and/or allometric relationships were established with regard to total soft mass of the mussels between 20 and 60 mm shell length. Relative amounts of taurine dropped significantly with increasing mass of whole soft tissues with an allometric coefficient value of − 0.15. The inverse relationship between taurine and increasing size of mussels was confirmed for gill epithelium and labial palp (allometric coefficient values of − 0.16 and − 0.10, respectively), tissues that, in turn, represented isometric functions with regard to total soft mass. Although relative amounts of taurine were significantly different in digestive gland, mantle and foot, relationships with increasing size of mussels remained unchanged in these tissues. Gill area of mussels was related to soft mass with an allometric coefficient of 0.70 by 2D Image Analysis, but increased to 0.85 when introducing a third dimension, i.e. gill thickness. Results are discussed according to gill structure analysis and taurine functionality.This study was supported by the contract-project PROINSA, Code CSIC 2004448, Galicia PGDIT03RMA13E. JMFB acknowledges funding by the Program Ramón y Cajal 2003 from Ministry of Education and Science (Spain).Peer reviewe

Una propuesta neoinstitucional en la transacción a la democracia: El parlamentarismo como perspectiva integradora.

México enfrenta actualmente un proceso en la consolidación de su democracia, aun después de la transición democrática, han surgido nuevos problemas en la definición del sistema político que tiene que ver en la manera en que se ejerce el poder, en cómo se distribuye y sobre todo como se regula mediante la ley. En los últimos años se ha experimentado un cambio radical en la política del país, pasando de un régimen autoritario con una sociedad poco participativa y sumisa a la autoridad presidencial a un régimen democrático, competitivo y plural en el cual la sociedad hace entrever cada vez más sus necesidades y para ello se muestra más participativa y critica ante la política nacional. Esto ha traído consigo nuevas dificultades para el gobierno y en la inclusión de las diferentes demandas sociales e individuales, algunos de estos problemas tienen origen en el sistema presidencial mexicano, aún vigente desde 1917 pero que ahora funciona bajo un contexto democrático que supone la existencia de frenos, contrapesos y la generación de acuerdos para hacer funcional al gobierno y al sistema mismo

Transient Propagation and Scattering of Quasi-Rayleigh Waves in Plates: Quantitative comparison between Pulsed TV-Holography Measurements and FC(Gram) elastodynamic simulations

We study the scattering of transient, high-frequency, narrow-band quasi-Rayleigh elastic waves by through-thickness holes in aluminum plates, in the framework of ultrasonic nondestructive testing (NDT) based on full-field optical detection. Sequences of the instantaneous two-dimensional (2-D) out-of-plane displacement scattering maps are measured with a self-developed PTVH system. The corresponding simulated sequences are obtained by means of an FC(Gram) elastodynamic solver introduced recently, which implements a full three-dimensional (3D) vector formulation of the direct linear-elasticity scattering problem. A detailed quantitative comparison between these experimental and numerical sequences, which is presented here for the first time, shows very good agreement both in the amplitude and the phase of the acoustic field in the forward, lateral and backscattering areas. It is thus suggested that the combination of the PTVH system and the FC(Gram) elastodynamic solver provides an effective ultrasonic inspection tool for plate-like structures, with a significant potential for ultrasonic NDT applications.Comment: 46 pages, 16 figures, corresponding author Jos\'e Carlos L\'opez-V\'azquez, [email protected]. Changes: 1st, 4th, 5th paragraphs (intro), 3rd, 4th paragraphs (sec. 4); [59-60] cited only in appendixes; old ref. [52] removed; misprints corrected in the uncertainty of c_L (subsec. 3.1), citation to fig. 10 (sec. 4), size of images (caption fig.15); reference to Lam\'e constants removed in subsec. 3.

Conformationally-Locked C-Glycosides: Tuning Aglycone Interactions for Optimal Cheperone Behaviour in Gaucher Fibroblasts

A series of conformationally locked C-glycosides based on the 3-aminopyrano[3,2-b]pyrrol-2(1H)-one (APP) scaffold has been synthesized. The key step involved a totally stereocontrolled C-Michael addition of a serine-equivalent C-nucleophile to tri-O-benzyl-2-nitro-D-galactal, previously published by the authors. Stereoselective transformations of the Michael adduct allowed us the synthesis of compounds with mono- or diantennated aglycone moieties and different topologies. In vitro screening showed highly selective inhibition of bovine liver β-glucosidase/β-galactosidase and specific inhibition of human β-glucocerebrosidase among lysosomal glycosidases for compounds bearing palmitoyl chains in the aglycone, with a marked dependence of the inhibition potency upon their number and location. Molecular dynamics simulations highlighted the paramount importance of an optimal orientation of the hydrophobic substituent to warrant efficient non-glycone interactions, which are critical for the binding affinity. The results provide a rationale for the strong decrease of the inhibition potency of APP compounds on going from neutral to acidic pH. The best candidate was found to behave as pharmacological chaperone in Gaucher fibroblasts with homozygous N370S and F213I mutations, with enzyme activity enhancements similar to those encountered for the reference compound AmbroxolMinisterio de Economía y Competitividad CTQ2012-36365, SAF2013-44021-RJunta de Andalucía FQM-1467European Union Seventh Framework Programme FP7-People-2012-CI

Red-Emitting Tetracoordinate Organoboron Chelates: Synthesis, Photophysical Properties, and Fluorescence Microscopy

Seven tetracoordinate organoboron fluorophores with heterobiaryl N,O- or N,N-chelate ligands were prepared and photophysically characterized (in toluene). The electronic variation of the heteroaromatic moiety provided a means for the fine-tuning of the UV/vis absorption and emission spectra. In the most interesting cases, the spectra were red-shifted to maximum absorbance at wavelengths longer than 500 nm and emission maxima between 620 and 660 nm. The pronounced intramolecular charge-transfer character of the dyes yielded large Stokes shifts (3500-5100 cm), while maintaining appreciable fluorescence quantum yields of up to 0.2 for emission maxima longer than 600 nm. The lipophilic character of the dyes enabled their application as stains of vesicle substructures in confocal fluorescence microscopy imaging.Ministerio de Economía y Competitividad CTQ2014-54729 - C2 - 1 - P for U.P., CTQ2013 - 48164 - C2 - 1 - P , CTQ2013 - 48164 - C2 - 2 - P for A.R., CTQ2013 - 41339 - P, CTQ2015 - 71896 - REDT for E.P.I., Ramón y Cajal contract RYC - 2013 - 12585 for A.R.FEDER FundJunta de Andalucía 2012/FQM - 2140 for U.P., 2009/FQM - 4537 and 2012/FQM - 1078 for A.R

El hidrógeno como vector energético: Mucho hecho pero casi todo por hacer

Los autores desarrollan, muy brevemente, los aspectos esenciales de lo que globalmente se denomina “Sistema Energético Solar-Hidrógeno” o a veces “Economía del hidrógeno”. El hidrógeno, obtenido por descomposición del agua mediante energías primarias renovables (solar, eólica…) se convierte en transportador de energía (vector energético) y en combustible limpio. Se discute la conveniencia del uso del hidrógeno en el contexto energético actual, así como los tres pilares fundamentales del uso del hidrógeno como vector energético: su producción usando fuentes renovables, su acumulación mediante diferentes métodos y, finalmente, su combustió