1,913 research outputs found
Model of the polarized foreground diffuse Galactic emissions from 33 to 353 GHz
We present 3D models of the Galactic magnetic field including regular and
turbulent components, and of the distribution of matter in the Galaxy including
relativistic electrons and dust grains. By integrating along the line of sight,
we construct maps of the polarized Galactic synchrotron and thermal dust
emissions for each of these models. We perform a likelihood analysis to compare
the maps of the Ka, Q, V and W bands of the Wilkinson Microwave Anisotropy
Probe (Wmap) and the 353 GHz Archeops data to the models obtained by varying
the pitch angle of the regular magnetic field, the relative amplitude of the
turbulent magnetic field and the extrapolation spectral indices of the
synchrotron and thermal dust emissions. The best-fit parameters obtained for
the different frequency bands are very similar and globally the data seem to
favor a negligible isotropic turbulent magnetic field component at large
angular scales (an anisotropic line-of-sight ordered component can not be
studied using these data). From this study, we conclude that we are able to
propose a consistent model of the polarized diffuse Galac- tic synchrotron and
thermal dust emissions in the frequency range from 33 to 353 GHz, where most of
the CMB studies are performed and where we expect a mixture of these two main
foreground emissions. This model can be very helpful to estimate the
contamination by foregrounds of the polarized CMB anisotropies, for experiments
like the Planck satellite.Comment: 22 pages, 4 figure
Mathematical Modeling of the Mojave Solar Plants
Competitiveness of solar energy is one of current main research topics. Overall efficiency
of solar plants can be improved by using advanced control strategies. To design and tuning properly
advanced control strategies, a mathematical model of the plant is needed. The model has to fulfill
two important points: (1) It has to reproduce accurately the dynamics of the real system; and (2) since
the model is used to test advanced control strategies, its computational burden has to be as low as
possible. This trade-off is essential to optimize the tuning process of the controller and minimize the
commissioning time. In this paper, the modeling of the large-scale commercial solar trough plants
Mojave Beta and Mojave Alpha is presented. These two models were used to test advanced control
strategies to operate the plants.Comisión Europea OCONTSOLAR 78905
Data for mine soils reclamation at Galicia: naturall capacity and choices for amelioration
[Resumen] Se estudian las principales limitaciones para la recuperación de los suelos de explotaciones mineras de la provincia de La Coruña. A pesar de que hay una gran heterogeneidad, especialmente en aspectos como textura, pedregosidad y/o rocosidad, puede se ñalarse que las mayores dificultades para la revegetación derivan de la pobreza en materia orgánica y de la baja fertilidad actual y potencial, manifestada en la escasez de P, N y de reservas minerales. Los procesos· de toxicidad relativamente escasos, están relacionados con ambientes extremadamente ácidos en los que pueden encontrarse altos niveles de Al en el complejo de cambio y metales pesados en formas solubles. La pedregosidad es un limitante importante en algunas escombreras de dunitas, anfibolitas y esquistos ricos en cuarzo. Parece aconsejable la implantación de especies pioneras, frugales y tolerantes y, si es posible, con intervención de leguminosas. El aporte de residuos o subproductos ricos en materia orgánica tales como: lodos de depuradoras o industrias de la alimentación, compost de residuos sólidos urbanos, subproductos de industrias de la madera... o de materiales que deben ser removidos (lodos fluviales o de estuario, desmontes... ) son favorables siempre y cuando tengan una composición complementaria con la de los escombros o materiales de mina a recuperar.[Abstract] Mine soils at La Coruña (NW Spain) are studied in order to know their main limitations for reclamation. In spite of their heterogeneity (texture, stoniness) the main limitations for revegetation are: low levels of organic matter and low fenility, current (small amounts ofP and N) and potential (small) pool of weatherable (minerals). The relatively rare toxicity processes are related to very acidic environments, where high levels of exchangeable aluminium and heavy metals can occur. Stoniness is limitant in sorne dunites, amphibolites and quartz-schist spoils. It seems to be advisable a revegetation with pioneers, frugal and tolerant species, and, if possible, including leguminous. Treatments with organic amendments: municipal sewage sludge, compost, paper mill wastes, sawdust, or materials manipulated by man (river and estuary sludges, moved earthy materials) is favourable if their composition is complementary with the mine spoil
Hierarchically-structured metalloprotein composite coatings biofabricated from co-existing condensed liquid phases
Complex hierarchical structure governs emergent properties in biopolymeric materials; yet, the material processing involved remains poorly understood. Here, we investigated the multi-scale structure and composition of the mussel byssus cuticle before, during and after formation to gain insight into the processing of this hard, yet extensible metal cross-linked protein composite. Our findings reveal that the granular substructure crucial to the cuticle’s function as a wear-resistant coating of an extensible polymer fiber is pre-organized in condensed liquid phase secretory vesicles. These are phase-separated into DOPA-rich proto-granules enveloped in a sulfur-rich proto-matrix which fuses during secretion, forming the sub-structure of the cuticle. Metal ions are added subsequently in a site-specific way, with iron contained in the sulfur-rich matrix and vanadium coordinated by DOPA-catechol in the granule. We posit that this hierarchical structure self-organizes via phase separation of specific amphiphilic proteins within secretory vesicles, resulting in a meso-scale structuring that governs cuticle function
MIMAC-He3 : A Micro-TPC Matrix of Chambers of He3 for direct detection of Wimps
The project of a micro-TPC matrix of chambers of \hetrois for direct
detection of non-baryonic dark matter is presented. The privileged properties
of He3 are highlighted. The double detection (ionization - projection of
tracks) is explained and its rejection evaluated. The potentialities of
MIMAC-He3 for supersymmetric dark matter search are discussed.Comment: to appear in Proc. of the 9th International Conference on Topics in
Astroparticle and Underground Physics (TAUP 2005), Zaragoza, Sept. 200
Contribución a la caracterización químico-mineralógica de los esquistos del "Complejo de Ordes"
[Resumen] Se presentan los datos qUlmlcos y mineralógicos de 77 muestras de rocas esquistosas de la "Unidad Betanzos-Arzúa", perteneciente al "Complejo de Ordes" , con objeto de analizar la variabilidad existente y discutir las posibilidades de sectorización de los distintos tipos de rocas en función de parámetros de composición.[Abstract] This paper presents the chemical and mineralogical composi tion of 77 samples of schi ts belonging to the "Unit of Betanzos-Arzua" , included in the "Ordenes Complex" . Tqe data were used to make an analysis the variability in the composi tion of the rocks and a subdivision of the " Unidad " based on the rock characteristics was intented
Evolución geoquímica de las rocas gabroicas de Galicia durante su meteorización
[Resumen] Se realiza un estudio de la evolución geoquímica de las rocas gabroicasdel macizo de Monte Castelo (La Coruña) en el curso de su meteorización .En medios bien drenados se produce una fuerte pérdida de bases, y en menor medida de Si, ya desde las primeras fases de la alteración, por el, contrario, en tos medios donde la hidromorfia es permanente la lixiviación de bases decrece, la movilidad del Si se aproxima a la del Al y se incrementa la del Fe y el Mn.[Abstract] This paper is a study of the geochemical evolution of the gabbroic rocks of Monte Castelo (La Coruña) in the progress of their üJeathering •In üJell drained envirorunents there are an intense l03S of bases and, in a minor level, of Si, even in the first phases of the üJeathering; but in hydromorphic énvironments , the leach of bases decreases ; the movitity of Si comes near of the Al and that of Fe and Mn increases
Recent sediments of the Eume river: mineralogical and textural composition
[Resumen] Se analiza la granulometría, textura y mineralogía de sedimentos recogidos en los fondos de la ría de Ares, estuario y tramo final del río Eume. Texturalmente, las muestras se agrupan en francolimosas o francoarenosas y su distribución está defmida según las características dinámicas de la ría y las modificaciones realizadas por las obras de infraestructura. La mineralogía de la fracción arcilla es muy homogénea, con caolinita y filosilicatos 2: 1 dominantes, junto con pequeñas antidades de cuarzo y feldespato. El contenido en carbonatos es bajo, siempre menor del 30 %, destacando los porcentajes encontrados en el sondeo de la cola del embalse del Eume, de origen claramente antrópico. Textura y mineralogía son coherentes con el marco geológico del que proceden, excepto en la presencia de carbonatos y exceso de partículas finas con caolinita cristalina existentes en la cola del embalse del Eume. La distribución de las partículas, según su tamaño, obedece fundamentalmente a causas naturales, pero existen imponantes modificaciones relacionadas con el papel de barrera del embalse y las obras de infraestructura que han alterado la circulaci6n original en algunas zonas del estuario y desembocadura.[Abstract] A textural and mineralogical analysis is made to sediments sampled at the bottom of the Ría de Ares, estuarine and Eume river. Clay mineralogy is very similar for all the samples and consists of kaolinite and 2: 1 phyllosilicates with small amounts of quartz and fe'ldspar. The percentage of carbonates is small, always less than 30 o/o. There should be pointed out the values found in the Eume reservoir core, with a clear antropic origino Texture and mineralogy are coherent with the geology of the basin they come from, excepting the carbonates and fine particle excess with cristaline caolinite in the Eume reservoir core. Size grain distribution is due to the dinamic characteristics of the ría, but there are important rnodifications related to the reservoir, that acts as a barrier, and the constructions in the lower part of the river that have changed the original circulation in sorne areas of the ría
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