排序方式： 共有27条查询结果，搜索用时 171 毫秒
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Pierre Kaufmann Rogério Marcon André Abrantes Emilio C. Bortolucci Luis Olavo T. Fernandes Grigory I. Kropotov Amauri S. Kudaka Nelson Machado Adolfo Marun Valery Nikolaev Alexandre Silva Claudemir S. da Silva Alexander Timofeevsky 《Experimental Astronomy》2014,37(3):579-598
The search for the still unrevealed spectral shape of the mysterious THz solar flare emissions is one of the current most challenging research issues. The concept, fabrication and performance of a double THz photometer system, named SOLAR-T, is presented. Its innovative optical setup allows observations of the full solar disk and the detection of small burst transients at the same time. The detecting system was constructed to observe solar flare THz emissions on board of stratospheric balloons. The system has been integrated to data acquisition and telemetry modules for this application. SOLAR-T uses two Golay cell detectors preceded by low-pass filters made of rough surface primary mirrors and membranes, 3 and 7 THz band-pass filters, and choppers. Its photometers can detect small solar bursts (tens of solar flux units) with sub second time resolution. Tests have been conducted to confirm the entire system performance, on ambient and low pressure and temperature conditions. An artificial Sun setup was developed to simulate performance on actual observations. The experiment is planned to be on board of two long-duration stratospheric balloon flights over Antarctica and Russia in 2014–2016. 相似文献
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Luísa D.V.Carvalho Tiago Jalowitzki Ricardo Scholz Guilherme O.Gonalves Marcelo Peres Rocha Rogério Silvestre Pereir Cristiano Lana Marco Paulo de Castro Gláucia Queiroga Reinhardt A.Fuck 《地学前缘(英文版)》2022,(1):182-203
We present major and trace element compositions of mineral concentrates comprising garnet xenocrysts,ilmenite,phlogopite,spinel,zircon,and uncommon minerals (ti... 相似文献
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Maedo Michael Sánchez Marcelo Aljeznawi Duaa Manzoli Osvaldo Guimarães Leonardo J. N. Cleto Pedro Rogério 《Acta Geotechnica》2020,15(9):2619-2635
This paper focuses on the shrinkage behavior of soil specimens involving sand, kaolinite, and kaolinite/sand mixtures subjected to desiccation under controlled conditions. Both, free and restrained shrinkage conditions are studied. The experiments show that pure soils do not curl upon unrestrained shrinkage; however, (under the same conditions) kaolinite/sand mixtures exhibited a marked curling. Furthermore, the mixture with the higher sand content broke through the middle of the sample after displaying a significant curling. Soils subjected to restricted shrinkage developed cracks with slight curling. To simulate the observed behavior, a mechanical model able to reproduce the detachment of the soil sample from the mold is proposed in this work and implemented in a fully coupled hydro-mechanical finite-element code. It is concluded that suction and differential shrinkage are key factors influencing the curling behavior of soils. The proposed framework was able to satisfactorily explain and reproduce the different stages and features of soil behavior observed in the experiments.
相似文献5.
Silva Vinicius Oliveira de Mello Carlos Rogério Chou Sin Chan 《Theoretical and Applied Climatology》2022,148(3-4):1289-1302
Theoretical and Applied Climatology - South of Minas Gerais state, in Southeast Brazil, is known for the coffee crop production (more than 30% of country’s production) and hydroelectricity... 相似文献
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Excelso Ruberti Gaston E. R. Enrich Rogério G. Azzone Piero Comin-Chiaramonti Angelo De Min Celso B. Gomes 《Mineralogy and Petrology》2012,104(1-2):63-80
The Cretaceous Banhad?o alkaline complex in southeastern Brazil presents two potassic SiO2-undersaturated series. The high-Ca magmatic series consist of initially fractionated olivine (Fo92-91) + diopside (Wo48-43En49-35Ae0-7), as evidenced by the presence of xenocrysts and xenoliths. In that sequence, diopside (Wo47-38En46-37Ae0-8) + phlogopite + apatite + perovskite (Prv>92) crystallized to form the phlogopite melteigite and led to the Ca enrichment of the magma. Diopside (Wo47-41En32-24 Ae3-14) continued to crystallize as an early mafic mineral, followed by nepheline (Ne74.8-70.1Ks26.3-21.2Qz7.6-0.9) and leucite (Lc65-56) and subsequently by melanite and potassic feldspar (Or85-99Ab1-7) to form melanite ijolites, wollastonite-melanite urtites and melanite-nepheline syenites. Melanite-pseudoleucite-nepheline syenites are interpreted to be a leucite accumulation. Melanite nephelinite dykes are believed to represent some of the magmatic differentiation steps. The low-Ca magmatic series is representative of a typical fractionation of aegirine-augite (Wo36-29En25-4Ae39-18) + alkali feldspar (Or57-96Ab3-43) + nepheline (Ne76.5-69.0Ks19.9-14.4Qz15.1-7.7) + titanite from phonolite magma. The evolution of this series from potassic nepheline syenites to sodic sodalite syenites and sodalitolites is attributed to an extensive fractionation of potassic feldspar, which led to an increase of the NaCl activity in the melt during the final stages forming sodalite-rich rocks. Phonolite dykes followed a similar evolutionary process and also registered some crustal assimilation. The mesocratic nepheline syenites showed interactions with phlogopite melteigites, such as compatible trace element enrichments and the presence of diopside xenocrysts, which were interpreted to be due to a mixing/mingling process of phonolite and nephelinite magmas. The geochemical data show higher TiO2 and P2O5 contents and lower SiO2 contents for the high-Ca series and different LILE evolution trends and REE chondrite-normalized patterns as compared to the low-Ca series. The 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb and 208Pb/204Pb initial ratios for the high-Ca series (0.70407–0.70526, 0.51242–0.51251, 17.782–19.266 and 38.051–39.521, respectively) were slightly different from those of the low-Ca series (0.70542–0.70583, 0.51232–0.51240, 17.758–17.772 and 38.021–38.061, respectively). For both series, a CO2-rich potassic metasomatized lithospheric mantle enriched the source with rutile-bearing phlogopite clinopyroxenite veins. Kamafugite-like parental magma is attributed to the high-Ca series with major contributions from the melting of the veins. Potassic nephelinite-like parental magma is assigned to the low-Ca series, where the metasomatized wall-rock played a more significant role in the melting process. 相似文献
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Ocean Dynamics - One year of deep-water wave hourly records collected by a buoy deployed off Ceará state, northeastern Brazilian coast, were used to estimate some regional wave climate... 相似文献
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de Abreu Corrêa A Albarnaz JD Moresco V Poli CR Teixeira AL Oliveira Simões CM Monte Barardi CR 《Marine environmental research》2007,63(5):479-489
The State of Santa Catarina produces the greatest quantity of edible mollusks in Brazil. To guarantee sanitary qualify, mollusk cultures should be monitored for contamination by pathogenic microorganisms. A self-purification or "depuration" system that eliminates Salmonella enterica serovar Typhimurium contamination from oysters has been developed and evaluated. The depuration process occurred within a closed system, in which 1000 L of water was recirculated for 24 h. The water was sterilized with ultraviolet (UV) light, chlorine, or both together. Oysters (Crassostrea gigas) artificially contaminated with S. typhimurium were harvested every 6 h. Samples of oyster tissue were excised and both the presence and numbers of bacteria were determined. Combined UV light and chlorine treatments resulted in total elimination of bacteria within 12 h. Polymerase chain reaction detected bacteria in water exposed to the three treatments. This pioneering study is the first of its kind in Brazil and represents a major contribution to commercial mollusk culture in this country. 相似文献
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Energy Decay of the 2004 Sumatra Tsunami in the World Ocean 总被引：1，自引：0，他引：1
Alexander B. Rabinovich Rogério N. Candella Richard E. Thomson 《Pure and Applied Geophysics》2011,168(11):1919-1950
The catastrophic Indian Ocean tsunami generated off the coast of Sumatra on 26 December 2004 was recorded by a large number
of tide gauges throughout the World Ocean. This study uses gauge records from 173 sites to examine the characteristics and
energy decay of the tsunami waves from this event in the Indian, Atlantic and Pacific oceans. Findings reveal that the decay
(e-folding) time of the tsunami wave energy within a given oceanic basin is not uniform, as previously reported, but depends
on the absorption characteristics of the shelf adjacent to the coastal observation site and the time for the waves to reach
the site from the source region. In general, the decay times for island and open-ocean bottom stations are found to be shorter
than for coastal mainland stations. Decay times for the 2004 Sumatra tsunami ranged from about 13 h for islands in the Indian
Ocean to 40–45 h for mainland stations in the North Pacific. 相似文献
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Jean-Louis Dommergues Christian Meister Rogério B. Rocha 《Swiss Journal of Geoscience》2011,104(1):81-96
A review of the Pliensbachian ammonite faunas of the Algarve Basin is given covering their taxonomy, stratigraphy and palaeobiogeography
(palaeobiodiversity). This review is based on both an extensive revision of the previously collected and/or published material
and on new finds precisely located within the ammonite succession. This new material allows us to clarify the variations within
the most abundant species—a new species Reynesocoeloceras elmii nov. sp. is described—and to improve our understanding (palaeobiodiversity, palaeobiogeography and bio- or chrono-stratigraphy)
of the two single known Pliensbachian fossiliferous assemblages in the Algarve Basin. The first of these assemblages is relatively
diverse and is ascribed to the upper half of the Luridum Subchronozone. The second assemblage is less diversified and probably
partly condensed. It is broadly attributed to the upper half of the Stokesi Subchronozone. Despite the newly collected ammonites
and extensive prospecting, our knowledge of the Pliensbachian ammonite faunas of the Algarve remains fragmentary. Therefore,
it is difficult to propose an incontrovertible extensive palaeobiogeographical interpretation for these faunas, but it seems
that Tethyan (Mediterranean) affinities were of major importance whereas there were probably no NW European influences via
the Lusitanian Basin. 相似文献