8,694 research outputs found
Una nueva especie de Arachis (Fabaceae) de Mato Grosso, Brasil, afín a A. matiensis
In the original description of Arachis matiensis, two isolated populations, from the municipality of Cáceres, Mato Grosso State, Brazil, were listed as possibly representing a different species, but the analysis of additional materials, and further morphological study were considered necessary to reach a decision in that regard. New herbarium and germplasm collections in the area, additional morphological studies, and inter- and intraspecific crossing results now support the description of A. jacobinensis, a new species of the taxonomic section ProcumbentesEn la descripción original de Arachis matiensis, dos poblaciones brasileñas aisladas, del municipio de Cáceres, estado de Mato Grosso, Brasil, se destacaron como posiblemente pertenecientes a una especie distinta pero se consideró que era necesario realizar análisis de más materiales y estudios morfológicos adicionales para alcanzar una decisión en ese respeto. Nuevas colecciones de herbario y germoplasma en el área, estudios morfológicos complementarios y resultados de cruzamientos inter- e intraespecíficos sustentan ahora la descripción de A. jacobinensis, una nueva especie de la sección taxonómica Procumbente
A new species of Arachis (Fabaceae) from Mato Grosso, Brazil, related to Arachis Matiensis.
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Diseño de mezclas de hormigón reciclado mediante el método Volumen de Mortero Equivalente (EMV): Validación bajo el contexto español y su adaptación al método de diseño de Bolomey
A new method for proportioning recycled aggregates concrete (RAC) is used to check its feasibility under the Spanish context. First, an extensive experimental campaign has been done, with the purpose of check and analyze the applicability of the EMV method with two Spanish recycled concrete aggregates (RCA). The aim of the second part of the investigation, was to elaborate an adaptation of the EMV method to Bolomey methodology (1), using a 20% weight replacement of coarse natural aggregates (NA) for RCA, and so, with this, comply with the Spanish Instruction for Structural Concrete (EHE 2008). Slump, air content, fresh and hardened densities, compressive strength and modulus of elasticity were determined and analyzed, in order to check the concrete properties. Finally, it was observed that, the EMV method is viable, and its adaptation, results in concrete mixes with similar or better properties than the natural aggregate concrete and RAC conventionally prepared.El nuevo método para el diseño de hormigón con árido reciclado (HAR) es usado para comprobar su posibilidad de uso bajo el contexto español. Primeramente, se realiza una extensa campaña experimental, para analizar las posibilidades de su aplicación, usando dos áridos reciclados de hormigón (ARH) españoles. En la segunda etapa se elabora una adaptación del método a la metodología propuesta por Bolomey (1), con 20% de reemplazo en peso de árido grueso natural (AN) por ARH, para así cumplir con las recomendaciones estipuladas en la Instrucción de Hormigón Estructural (EHE 2008). Para determinar y analizar las propiedades del hormigón, se llevaron a cabo ensayos de asentamiento, contenido de aire, densidades, módulo elástico y resistencias a compresión. Finalmente, se concluye que el uso del nuevo método es viable, y que su adaptación produce hormigones con similares o mejores características que los elaborados para hormigón con árido convencional (HAC) y HAR convencionales
Superconducting proximity effects in metals with a repulsive pairing interaction
Studies of the superconducting proximity effect in normal
conductor/superconductor junctions almost universally assume no
effective electron-electron coupling in the region. While such an
approximation leads to a simple description of the proximity effect, it is
unclear how it could be rigorously justified. We reveal a much more complex
picture of the proximity effect in bilayers, where is a clean s-wave
BCS superconductor and is a simple metal with a repulsive effective
electron coupling. We elucidate the proximity effect behavior using a highly
accurate method to self-consistently solve the Bogoliubov-deGennes equations.
We present our results for a wide range of values of the interface scattering,
the Fermi wave vector mismatch, the temperature, and the ratio of the
effective interaction strengths in the and region. We find that the
repulsive interaction, represented by a negative , strongly alters the
signatures of the proximity effect as can be seen in the spatial dependence of
the Cooper pair amplitude and the pair potential, as well as in the local
density of states near the interface.Comment: 12 pages, including 10 figures. To appear in Phys. Rev.
Nonlinear Hydrodynamics of a Hard Sphere Fluid Near the Glass Transition
We conduct a numerical study of the dynamic behavior of a dense hard sphere
fluid by deriving and integrating a set of Langevin equations. The statics of
the system is described by a free energy functional of the
Ramakrishnan-Yussouff form. We find that the system exhibits glassy behavior as
evidenced through stretched exponential decay and two-stage relaxation of the
density correlation function. The characteristic times grow with increasing
density according to the Vogel-Fulcher law. The wavenumber dependence of the
kinetics is extensively explored. The connection of our results with
experiment, mode coupling theory, and molecular dynamics results is discussed.Comment: 34 Pages, Plain TeX, 12 PostScript Figures (not included, available
on request
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