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191.
Ioana Santos Eduardo Ferreira da Silva Carla Patinha Ana Cláudia Dias Amélia Paula Reis 《Environmental Earth Sciences》2013,69(5):1649-1660
The aim of this study is to assess the potential health risk posed by As and Pb in the soils of the Pintor mine area. The site was never remediated but a residential area is being constructed in the mine land, next to the smelters, a fact that raised some concern about the probable risk posed by potentially harmful elements in the soil to the health of the residents. 132 samples were collected and analyzed by ICP-MS to determine total metal concentrations. The soluble fraction of As in the soil was obtained using 1 M NH4 Acetate, pH 4.5. To assess the probable risk, total concentrations are compared with the soil guideline value established for the UK. Exposure through soil ingestion is probable in and around the residential area that has higher As and Pb concentrations, and therefore is classified as area with a potential health risk. 相似文献
192.
Wytler Cordeiro dos Santos 《Astrophysics and Space Science》2011,331(1):295-307
The Laser Interferometer Space Antenna (LISA) mission will use advanced technologies to achieve its science goals: the direct
detection of gravitational waves, the observation of signals from compact (small and dense) stars as they spiral into black
holes, the study of the role of massive black holes in galaxy evolution, the search for gravitational wave emission from the
early Universe. The gravitational red-shift, the advance of the perihelion of Mercury, deflection of light and the time delay
of radar signals are the classical tests in the first order of General Relativity (GR). However, LISA can possibly test Einstein’s
theories in the second order and perhaps, it will show some particular feature of non-linearity of gravitational interaction.
In the present work we are seeking a method to construct theoretical templates that limit in the first order the tensorial
structure of some metric fields, thus the non-linear terms are given by exponential functions of gravitational strength. The
Newtonian limit obtained here, in the first order, is equivalent to GR. 相似文献
193.
E. Aprile K. Arisaka F. Arneodo A. Askin L. Baudis A. Behrens K. Bokeloh E. Brown J.M.R. Cardoso B. Choi D. Cline S. Fattori A.D. Ferella K.L. Giboni A. Kish C.W. Lam J. Lamblin R.F. Lang K.E. Lim J.A.M. Lopes T. Marrodán Undagoitia Y. Mei A.J. Melgarejo Fernandez K. Ni U. Oberlack S.E.A. Orrigo E. Pantic G. Plante A.C.C. Ribeiro R. Santorelli J.M.F. dos Santos M. Schumann P. Shagin A. Teymourian D. Thers E. Tziaferi H. Wang C. Weinheimer M. LaubensteinS. Nisi 《Astroparticle Physics》2011,35(2):43-49
Results of the extensive radioactivity screening campaign to identify materials for the construction of XENON100 are reported. This dark matter search experiment is operated underground at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Several ultra sensitive High Purity Germanium detectors (HPGe) have been used for gamma ray spectrometry. Mass spectrometry has been applied for a few low mass plastic samples. Detailed tables with the radioactive contaminations of all screened samples are presented, together with the implications for XENON100. 相似文献
194.
M. E. Zucolotto L. L. Antonello M. E. Varela R. B. Scorzelli Isabel P. Ludka P. Munayco E. dos Santos 《Earth, Moon, and Planets》2012,108(2):139-150
The new Brazilian chondrite, Lavras do Sul, was found in 1985 at Lavras do Sul, Rio Grande do Sul State-Brazil (33°30′48″S; 53°54′65″W). It consists of a single mass weighing about 1 kg, covered by a black fusion crust with grayish interior. Four polished thin sections were prepared from a slice weighing 67 g on deposit at the Museu Nacional/UFRJ. It consists mostly of chondrules and chondrule fragments dispersed in a recrystallized matrix. Most chondrules are poorly defined and range in size from 300 to 2,000 μm, although some of them show distinct outlines, particularly when viewed under cross-polarized transmitted and reflected light. The texture of chondrules varies from non-porphyritic (e.g., barred-olivine, radial-pyroxene) to porphyritic ones (e.g., granular olivine as well as olivine-pyroxene). The meteorite contains mainly olivine (Fa24.9), low-Ca pyroxene (Fs22.6) and metal phases, with minor amounts of plagioclase, chromite and magnetite. Mössbauer Spectroscopy studies indicate that the metal phase is kamacite, tetrataenite and antitaenite. Veins of secondary iddingsite crosscut the thin section and some ferromagnesian silicates. The chemical composition indicates that Lavras do Sul is a member of the low iron L chondrite group. The poorly delineated chondritic texture with few well-defined chondrules, the occurrence of rare clinopyroxene and plagioclase (and maskelynite) with apparent diameters ranging from 5 to 123 μm led us to classify Lavras do Sul as an equilibrated petrologic type 5. The shock features of some minerals suggest a shock stage S3, and the presence of a small amount of secondary minerals such as iddingsite and goethite, a degree of weathering W1. The meteorite name was approved by the Nomenclature Committee (Nom Com) of the Meteoritical Society (Meteoritic Bulletin Nº99). 相似文献
195.
Emilio Santos 《Astrophysics and Space Science》2012,341(2):411-416
A gravity theory is considered with the Einstein-Hilbert Lagrangean R+aR 2+bR μν R μν , R μν being Ricci’s tensor and R the curvature scalar. The parameters a and b are taken of order 1 km2. Arguments are given which suggest that the effective theory so obtained might be a fair approximation of a viable theory. A numerical integration is performed of the field equations for a free neutron gas. The result is that the star mass increases with increasing central density until about 1 solar mass and then decreases. The baryon number increases monotonically, which suggests that the theory allows stars in equilibrium with arbitrary baryon number, no matter how large. 相似文献
196.
Alain Albouy Hildeberto E. Cabral Alan A. Santos 《Celestial Mechanics and Dynamical Astronomy》2012,113(4):369-375
Our idea is to imitate Smale’s list of problems, in a restricted domain of mathematical aspects of Celestial Mechanics. All the problems are on the n-body problem, some with different homogeneity of the potential, addressing many aspects such as central configurations, stability of relative equilibrium, singularities, integral manifolds, etc. Following Steve Smale in his list, the criteria for our selection are: (1) Simple statement. Also preferably mathematically precise, and best even with a yes or no answer. (2) Personal acquaintance with the problem, having found it not easy. (3) A belief that the question, its solution, partial results or even attempts at its solution are likely to have great importance for the development of the mathematical aspects of Celestial Mechanics. 相似文献
197.
Aline Meyer Ayan Santos Fleischmann Walter Collischonn Rodrigo Paiva Pedro Jardim 《水文科学杂志》2013,58(15-16):2035-2047
ABSTRACTAn accurate comprehension of celerity (flood wave speed) dynamics is a key step for understanding flood wave propagation in rivers. We present the results of empirically estimated celerity values in 12 Brazilian rivers, and analyse the behaviour of celerity–discharge relationships (CxQ). Celerity was estimated with a reach-scale (RS) method, based on the peak travel time between stations; and with a local-scale (LS) method, based on the derivative of discharge–cross-section area relationships surveyed at gauging stations. The results indicate that the magnitudes of celerity values obtained by the methods are reasonably comparable, and can rarely be considered constant, varying with river discharge. Three reaches presented differing CxQ relationships at local and reach scales, which suggests that in situ cross-sections at gauging stations should not be extrapolated as representative of the whole reach for flood routing studies, and that CxQ relationship assessments might provide relevant insights for hydrological modelling. 相似文献
198.
199.
Ana Lorena Esteban‐García Raquel Lebrero Manuel Alejandro de los Santos Raúl Muñoz Juan Ignacio Tejero 《洁净——土壤、空气、水》2013,41(5):469-472
A study was performed in two submerged, pilot‐scale biofilm bioreactors operated under different conditions to determine the relationship between the operating parameters and H2S emission. H2S was always detected in the exhaust air at concentrations varying from 1 to 353 ppmv. The specific aeration rate was the most influencing parameter, with As < 30 kg COD (dissolved oxygen concentrations <4 mg L?1) increasing noticeably the H2S production. The periodical removal of the accumulated sludge reduced H2S emissions by ~14%. 相似文献
200.
Javier Santos-González João A. Santos Rosa Blanca González-Gutiérrez José María Redondo-Vega Amelia Gómez-Villar 《自然地理学》2013,34(6):471-490
Fabric and grain-size analysis of eight deposits present in the Upper Sil River Basin palaeoglacial system of northwest Spain were used to interpret till types and to reconstruct the glacial paleoprocess history of this region. They are represented by lodgement, deformation, and melt-out tills. The first, representative of glacial advance stages, present cluster fabrics and are generally composed of poorly sorted and finer sediments. Melt-out and deformation tills, representative of stages of glacial stability followed by fast recession, present transitional to girdle fabrics and are composed of poorly sorted coarser sediments. In any case, multiple criteria, including lithological, clast-shape, or structural data, support these directional and grain-size observations. These sequences, most of them located in the snout area of the Sil palaeoglacier, are important in the reconstruction of glacial dynamics due to poor preservation of landforms related to the maximum glacial advance. This palaeoglacial system was formed by multiple tributaries and had an extension of over 450 km2, with the Sil paleoglacier being 51 km long during its maximum glacial advance. 相似文献