Operating Parameters Affecting the Formation of Kaolin Aerated Flocs in Water and Wastewater Treatment          下载免费PDF全文

Cristiane Oliveira  Rafael Teixeira Rodrigues  Jorge Rubio 《洁净——土壤、空气、水》2014,42(7):909-916

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Spatial distribution of metals in sediments of the Ribeira Bay, Angra dos Reis, Rio de Janeiro, Brazil   总被引：1，自引：0，他引：1  

N.V. Freret-Meurer  J.V. Andreata  B.C. Meurer  F.V. Manzano  M.G.S. Baptista  D.E. Teixeira  M.M. Longo 《Marine pollution bulletin》2010,60(4):627-629

This study aims to analyze the spatial distributions of several metals in sediments from five sites in Ribeira Bay, Brazil. Ribeira Bay is a very important area to the local community, due to its artisan fishery, and it also has a biological relevance for many marine species that use mangroves as nursery and feeding sites. According to the results, the area was not considered a metal polluted area. Despite not having a significant source of metals inside the Bay nowadays, Ilha Grande Bay harbors a shipyard, an oil terminal, and a commercial port, as well as two thermonuclear power plants (Angra I e II), all of which indirectly influence the study area.  相似文献   

Gravity data as a tool for landfill study     

João B. C. Silva  Wlamir A. Teixeira  Valéria C. F. Barbosa 《Environmental Geology》2009,57(4):749-757

This paper shows the potential of gravity data to map a buried landfill bottom topography. To this end, a gravity inversion method is presented for estimating the landfill’s bottom depths at discrete points assuming a decrease of the density contrast with depth according to a hyperbolic law. The method’s efficiency was tested using synthetic data from simulated waste landfills, producing estimated bottom topographies very close to the true ones. The method’s potentiality has been further evaluated in applying it to the gravity data from the abandoned Thomas Farm Landfill site, Indiana, USA, whose bottom topography is known. The estimated topography showed close agreement with the known Thomas Farm Landfill’s bottom topography.  相似文献   

Spitzer imaging of the jet driving the NGC 2264 G outflow     

P. S. Teixeira  C. McCoey  M. Fich  C. J. Lada 《Monthly notices of the Royal Astronomical Society》2008,384(1):71-76

We present new infrared imaging of the NGC 2264 G protostellar outflow region, obtained with the InfraRed Array Camera (IRAC) onboard the Spitzer Space Telescope . A jet in the red outflow lobe (eastern lobe) is clearly detected in all four IRAC bands and, for the first time, is shown to continuously extend over the entire length of the red outflow lobe traced by CO observations. The redshifted jet also extends to a deeply embedded Class 0 source, Very Large Array (VLA) 2, confirming previous suggestions that it is the driving source of the outflow ( Gómez et al. 1994 ). The images show that the easternmost part of the redshifted jet exhibits what appear to be multiple changes of direction. To understand the redshifted jet morphology, we explore several mechanisms that could generate such apparent changes of direction. From this analysis, we conclude that the redshifted jet structure and morphology visible in the IRAC images can be largely, although not entirely, explained by a slowly precessing jet (period ≈8000 yr) that lies mostly on the plane of the sky. It appears that the observed changes in the redshifted jet direction may be sufficient to account for a significant fraction of the broadening of the outflow lobe observed in the CO emission.  相似文献   

Application of laser anemometry for measuring critical bed shear stress of sediment core samples     

M.A.V.C. Araújo  J.C.F. Teixeira  S.F.C.F. Teixeira 《Continental Shelf Research》2008

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Assessing Uncertainty Associated with the Delineation of Geochemical Anomalies   总被引：2，自引：0，他引：2  

Costa  Joao Felipe  Koppe  Jair Carlos 《Natural Resources Research》1999,8(1):59-67

A pedogeochemical exploratory survey of gold deposits was carried out in the region of São Sepé (southernmost Brazil). The region comprises a predominantly metamorphosed belt of volcanoclastics, sediments, serpentinites, basalts, gabbros, chert, tuffs, and banded iron formation of the Proterozoic age. The anomalies were identified first by stream sediment heavy mineral survey at the regional scale of exploration. Once spatial continuity was modeled, ordinary block kriging was performed to generate geochemical maps. Indicator block kriging also was used as an alternative in analyzing and interpreting geochemical data. A novel approach is proposed, which combines both ordinary and indicator kriging for delineating geochemical anomalies. Probability maps proved to be appropriate for selecting new sites for further exploration. Gold anomalies in soils trending NE were well defined by geostatistical analysis and subsequently confirmed by drilling.  相似文献   

Determination of Te,As, Bi,Sb and Se (TABS) in Geological Reference Materials and GeoPT Proficiency Test Materials by Hydride Generation‐Atomic Fluorescence Spectrometry (HG‐AFS)     

Eduardo Teixeira Mansur  Sarah‐Jane Barnes  Dany Savard  Peter C. Webb 《Geostandards and Geoanalytical Research》2020,44(1):147-167

The study of Te, As, Bi, Sb and Se (TABS) has increased over the past years due to their use in the development of low‐carbon energy technologies. However, there is a scarcity of mass fraction values of TABS in geological reference materials. This underlines the difficulty in undertaking routine determinations of these elements. The mass fractions of TABS were determined in geological reference materials using hydride generation‐atomic fluorescence spectrometry (HG‐AFS), calibrated with standard solutions. Comparisons with literature values were used to validate the method. Samples from the GeoPT proficiency test were also analysed. For most elements, there are no assigned or even provisional values for many of the GeoPT and reference materials because of the wide range of results reported. For mass fractions above the quantification limit of the method, our results are in good agreement with the median of GeoPT results. Thus, we propose GeoPT median values as informational values for these elements. In contrast, at mass fractions < 0.5 µg g^?1 median values of Se from GeoPT are systematically higher than our results. Our Se results are in agreement with the reference materials down to 0.02 µg g^?1, which suggest that many of the results for Se reported in GeoPT testing are too high.  相似文献   

Solid co spectroscopy: embedded ysos in taurus-auriga     

T. C. Teixeira  J. P. Emerson 《Astrophysics and Space Science》1995,224(1-2):573-574

Infrared spectra of the 4.67µm solid CO feature were obtained for YSOs in Taurus. A first attempt is made to analyse the likely composition of the CO ices. Column densities are derived from the spectra, and compared with the ones predicted for a low mass protostar. The strengths of the CO- and water-ice features towards those objects are compared.TCT supported by grant BD/2095/92-RM from JNICT- Programa CIENCIA, Portugal  相似文献   

Petrogenesis of the Paleoproterozoic basalt–andesite–rhyolite dyke association in the Carajás region, Amazonian craton     

Giorgio Rivalenti  Maurizio Mazzucchelli  Vicente Antonio Vitorio Girardi  Giancarlo Cavazzini  Cristina Finatti  Maria Adelaide Barbieri  Wilson Teixeira 《Lithos》1998,43(4):235-265

Paleoproterozoic basaltic, andesitic and rhyolitic dykes crosscut the Archaean Carajás basement. Basalts are distinguished into a high and a low TiO₂ group (HTi and LTi), each group consisting of geochemically distinct NE- and NW-trending swarms. The HTi dykes are evolved transitional basalts having essentially EMORB-type geochemistry. The LTi basalts are tholeiites (NE-trending swarm) and high-Al basalts (NW-trending swarm) displaying incompatible trace elements patterns with variably negative Nb anomaly, enrichment in Rb, Ba, K (LILE) and La, Ce and Nd (LREE) and positive Sr anomaly. With respect to orogenic analogues, andesites have lower Al₂O₃, CaO and Ni, higher FeO, LILE, LREE, Nb, Zr and Ti and negative Sr anomaly. Rhyolites have geochemical characteristics comparable with those of A-type granites. At 1.8 Ga, ranges from 0.700 to 0.705 in the HTi basalts and from 0.700 to 0.704 in the LTi group. Andesites define an isochron of 1874±110 Ma (Sr_o=0.7038±0.0010). Rhyolites from Southern and Northern Carajás define two isochrons of 1802±130 Ma (Sr_o=0.7062±0.0046) and 1535±82 Ga (Sr_o=0.7625) respectively, the younger date being interpreted as resetting of the Rb–Sr isotopic system. We propose a petrogenetic model relating LTi basalts with melting of lithospheric mantle metasomatized by acid melts derived from incipient melting of eclogites, representing in turn the subsolidus product of basaltic batches trapped in the mantle. The HTi basalts are explained by melting of the lithospheric mantle containing the complementary residual eclogite. Andesite petrogenesis is consistent with crystal fractionation from a high-Mg andesite parent derived from a mantle source more extensively metasomatized by eclogite-derived melts. Rhyolite composition is consistent with low melting degree of the basement rocks. The basalt–andesite–rhyolite dykes may represent the effects of crustal extension and arching in Carajás, which produced the anorogenic acid to intermediate magmatism (Uatumã group) and affecting a large part of the Amazon craton between 1.85 and 1.7 Ga.  相似文献   

CO Cocktails: Stirred...But Not Shaken     

T.C. Teixeira  J.P. Emerson  M.E. Palumbo 《Astrophysics and Space Science》1998,261(1-4):209-210

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