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51.
Cataclysmic Variables (CVs) are close binary systems where mass is transferred from a red dwarf star to a white dwarf star via an accretion disk. The flickering is observed as stochastic variations in the emitted radiation both in the continuum and in the emission line profiles.The main goal of our simulations is to compare synthetic Doppler maps with observed ones, aiming to constrain the flickering properties and wind parameters.A code was developed which generates synthetic emission line profiles of a geometrically thin and optically thick accretion disk. The simulation allows us to include flares in a particular disk region. The emission line flares may be integrated over arbitrary ‘`exposure’' times, producing the synthetic line profiles. Flickering Doppler maps are created using such synthetic time series. The presence of a wind inside the Roche lobe was also implemented. Radiative transfer effects in the lines where taken into account in order to reproduce the single peaked line profiles frequently seen in nova-like CVs. 相似文献
52.
Nicholas T. Okita Alexandre W. Camargo Jos Ribeiro Tiago A. Coimbra Caian Benedicto Jorge H. Faccipieri 《Geophysical Prospecting》2022,70(1):57-78
Modern subsurface imaging techniques allow obtaining high-quality images but with high computational costs. Nonetheless, depending on the amount of data, their execution is limited by memory in the current generation's hardware. However, with the advancement of new hardware and cloud-based solutions, these problems are mitigated but still with the risk of work loss and instability. To mitigate the execution problems in memory-limited and fail-prone environments, we propose two high-performance computing techniques. The first is based on independent checkpointing alongside a fault-tolerant framework to store an execution state and recover from that state in case of failures. Besides, for memory-limited graphics processing units, we present a technique to reduce the amount of memory requirement that we call the hybrid strategy. The experiments showed that the independent checkpointing alongside the fault-tolerant framework is able to mitigate the performance penalty of node failures, with the independent checkpointing technique being more relevant when multiple nodes are terminated. Furthermore, the hybrid strategy technique has shown the possibility of execution of larger models that could make the graphics processing unit run out of memory otherwise. Finally, our implementation is scalable, allowing a significant improvement in performance when adding new nodes. In conclusion, our techniques can be used to deliver fast, high-fidelity subsurface imaging in unstable and memory-limited environments, such as the cloud. 相似文献
53.
54.
Biomass allometric equation and expansion factor for a mountain moist evergreen forest in Mozambique
Sá Nogueira Lisboa Benard Soares Guedes Natasha Ribeiro Almeida Sitoe 《Carbon balance and management》2018,13(1):23
Background
Worldwide, forests are an important carbon sink and thus are key to mitigate the effects of climate change. Mountain moist evergreen forests in Mozambique are threatened by agricultural expansion, uncontrolled logging, and firewood collection, thus compromising their role in carbon sequestration. There is lack of local tools for above-ground biomass (AGB) estimation of mountain moist evergreen forest, hence carbon emissions from deforestation and forest degradation are not adequately known. This study aimed to develop biomass allometric equations (BAE) and biomass expansion factor (BEF) for the estimation of total above-ground carbon stock in mountain moist evergreen forest.Methods
The destructive method was used, whereby 39 trees were felled and measured for diameter at breast height (DBH), total height and the commercial height. We determined the wood basic density, the total dry weight and merchantable timber volume by Smalian’s formula. Six biomass allometric models were fitted using non-linear least square regression. The BEF was determined based on the relationship between bole stem dry weight and total dry weight of the tree. To estimate the mean AGB of the forest, a forest inventory was conducted using 27 temporary square plots. The applicability of Marzoli’s volume equation was compared with Smalian’s volume equation in order to check whether Marzoli’s volume from national forest inventory can be used to predict AGB using BEF.Results
The best model was the power model with only DBH as predictor variable, which provided an estimated mean AGB of 291?±?141 Mg ha?1 (mean?±?95% confidence level). The mean wood basic density of sampled trees was 0.715?±?0.182 g cm?3. The average BEF was of 2.05?±?0.15 and the estimated mean AGB of 387?±?126 Mg ha?1. The BAE from miombo woodland within the vicinity of the study area underestimates the AGB for all sampled trees. Chave et al.’s pantropical equation of moist forest did not fit to the Moribane Forest Reserve, while Brown’s equation of moist forest had a good fit to the Moribane Forest Reserve, having generated 1.2% of bias, very close to that generated by the selected model of this study. BEF showed to be reliable when combined with stand mean volume from Marzoli’s National Forestry Inventory equation.Conclusion
The BAE and the BEF function developed in this study can be used to estimate the AGB of the mountain moist evergreen forests at Moribane Forest Reserve in Mozambique. However, the use of the biomass allometric model should be preferable when DBH information is available.55.
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
56.
Elaine Nolasco Ribeiro Wilson Cabral de Sousa Jr Marcelo de Julio Wilfredo Urruchi Irrazabal Marcelo Antunes Nolasco 《洁净——土壤、空气、水》2013,41(7):627-634
One way to reduce water consumption in urban areas is by using alternative sources of supply that can be provided by collecting rainwater and reusing wastewater for less restricted purposes. Thus, this study evaluated the characteristics of effluents produced by the wastewater treatment plant (WWTP) of São Paulo International Airport (SPIA), Brazil, in order to reuse it in non‐potable situations. The results achieved, indicated high efficiency in the biological system utilized by SPIA. The removal rates is equal to or >90% for most of the parameters analyzed, among them, fluoride, salinity, nitrite, nitrate, ammonium nitrogen, total nitrogen, phosphorus, sedimentable solids, turbidity, conductivity, apparent color, chemical oxygen demand, biochemical oxygen demand, total organic carbon, fecal coliforms, and oils and greases. Despite the final effluents were good enough to be launched in the local streams, they shall be submitted to a complementary treatment in order to fit some quality parameters to be reused for specific demands (landscape irrigation, toilet flushing, vehicle washing, fire fighting, and dust control). 相似文献
57.
Makoto Naoi Masao Nakatani Shigeki Horiuchi Yasuo Yabe Joachim Philipp Thabang Kgarume Gilbert Morema Sifiso Khambule Thabang Masakale Luiz Ribeiro Koji Miyakawa Atsushi Watanabe Kenshiro Otsuki Hirokazu Moriya Osamu Murakami Hironori Kawakata Nana Yoshimitsu Anthony Ward Ray Durrheim Hiroshi Ogasawara 《Pure and Applied Geophysics》2014,171(10):2665-2684
We investigated frequency-magnitude distribution (FMD) of acoustic emissions (AE) occurring near an active mining front in a South African gold mine, using a catalog developed from an AE network, which is capable of detecting AEs down to M W ?5. When records of blasts were removed, FMDs of AEs obeyed a Gutenberg?Richter law with similar b values, not depending on post-blasting time from the initial 1-min interval through more than 30 h. This result denies a suggestion in a previous study (Richardson and Jordan Bull Seismol Soc Am, 92:1766–1782, 2002) that new fractures generated by blasting disturb the size distribution of background events, which they interpreted as slip events on existing weak planes. Our AE catalog showed that the GR law with b ~ 1.2 was valid between M W ?3.7 and 0 for AEs around the mining front. Further, using the mine’s seismic catalog, which covers a longer time period of the same area, we could extend the validity range of the GR law with the same b value up to M W 1. 相似文献
58.
M. J. Matias J. M. Marques P. Figueiredo M. J. Basto M. M. Abreu P. M. Carreira C. Ribeiro A. Flambó J. Feliciano E. M. Vicente 《Environmental Geology》2009,56(6):1227-1235
Santa Margarida Military Camp (S.M.M.C.) is the only one Portuguese military training area, including firing ranges for tactical
military manoeuvres of mechanised divisions. For this reason, various negative effects on the environment were expected due
to the military activities, as the Military Camp’s area is classified as a high vulnerability area to pollution of its multilayer
porous aquifers. The aim of this study was to identify and characterise local/regional geochemical impacts caused by the continuing
military training activities performed at S.M.M.C. in the course of 52 years. An overview of the geochemical research issues
as a basis for risk assessment is presented. A special attention has been put on the quality of local and regional surface
waters, shallow groundwaters and groundwaters. Local soils and sediments as well as fragments of shells and bullets were sampled
and analysed. The results so far obtained, indicated that none pollution effects were a consequence of the military training
activities. Till now, the geochemical signatures such as, high levels of K, Cl and NO3 in waters, detected in particular sites, should be faced as tracers of diffuse pollution ascribed to urban waste disposal
and cattle breading. 相似文献
59.
Morpho-tectonic analysis of the Azores Volcanic Plateau from a new bathymetric compilation of the area 总被引:13,自引:0,他引:13
Lourenço N. Miranda J.M. Luis J.F. Ribeiro A. Victor L.A. Mendes Madeira J. Needham H.D. 《Marine Geophysical Researches》1998,20(3):141-156
The existing studies of the Azores triple junction, although based on specific geological or geophysical data, largely rely upon morphological considerations. However, there is no systematic bathymetric coverage of this area, and the quality of the available bathymetric charts does not allow consistent morpho-structural analysis.In this work we present a new bathymetric grid elaborated with all the available data sources in an area comprised between 24° W to 32° W and 36° N to 41° N. The basic data set corresponds to the merge of NGDC data with new swath profiles. This new map, included as an Appendix, combined with other results from seismology and neotectonics, is the basis for the study of the morpho-structural pattern of the Azores area, the present day stress field and its implications on the current view of the Azores geodynamics.As a major result, we conclude that the Azores region is controlled by two sets of conjugated faults with 120° and 150° strikes that establish the framework for the onset of volcanism, expressing as linear volcanic ridges or as point source volcanism. This interaction develops what can be considered as the morphological signature of the Azores Spreading axis segmentation. We argue that the Azores domain, presently in a broad transtensional regime, is acting simultaneously as a ultra slow spreading centre and as a transfer zone between the MAR and the dextral Gloria Fault, as it accommodates the differential shear movement between the Eurasian and African plates. 相似文献
60.
Steven P. Oncley Thomas Foken Roland Vogt Wim Kohsiek H. A. R. DeBruin Christian Bernhofer Andreas Christen Eva van Gorsel David Grantz Christian Feigenwinter Irene Lehner Claudia Liebethal Heping Liu Matthias Mauder Andrea Pitacco Luis Ribeiro Tamas Weidinger 《Boundary-Layer Meteorology》2007,123(1):1-28
An overview of the Energy Balance Experiment (EBEX-2000) is given. This experiment studied the ability of state-of-the-art
measurements to close the surface energy balance over a surface (a vegetative canopy with large evapotranspiration) where
closure has been difficult to obtain. A flood-irrigated cotton field over uniform terrain was used, though aerial imagery
and direct flux measurements showed that the surface still was inhomogeneous. All major terms of the surface energy balance
were measured at nine sites to characterize the spatial variability across the field. Included in these observations was an
estimate of heat storage in the plant canopy. The resultant imbalance still was 10%, which exceeds the estimated measurement
error. We speculate that horizontal advection in the layer between the canopy top and our flux measurement height may cause
this imbalance, though our estimates of this term using our measurements resulted in values less than what would be required
to balance the budget.
The National Center for Atmospheric Research is supported by the National Science Foundation 相似文献