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91.
Rodrigues Karine dos Santos do Carmo Luiz Felipe Rodrigues Palmeira Ana Cristina Pinto de Almeida Andrioni Marcelo 《Natural Hazards》2022,110(3):2277-2302
Natural Hazards - After a storm displaced the P-70 platform ship located in Guanabara Bay to the coast on January 30, 2020, a numerical investigation was carried out with the BRAMS (Brazilian... 相似文献
92.
Marcela Mrquez-García Irma Vila Luis Felipe Hinojosa Marco A. Mndez Jos Luis Carvajal María Catalina Sabando 《Limnologica》2009,39(4):314-318
We compared the distribution and seasonal fluctuations in the aquatic biota in relation to chemical and physical water variables in the Altiplano watersheds of the Ascotán, Carcote and Huasco salars; Chungará and Cotacotani lakes; Isluga and Lauca Rivers and the Parinacota wetland. We sampled during the austral autumn–winter of 2006 and in the spring–summer of 2006–2007, using three sampling stations for each system. We used canonical correspondence analysis to establish relations between frequency of taxa and environmental variables.We demonstrate that the structure and composition of the aquatic biota in humid areas of the Altiplano is determined by physical and chemical variables of the water. The most relevant one is total nitrogen, which is also the limiting nutrient for phytoplankton production in tropical systems.Benthos and zooplankton showed significant associations with the set of environmental variables (Monte Carlo test, p<0.05); however, the association was not significant for phytoplankton. Lake Chungará showed the greatest variation in composition and abundance of zooplankton between autumn-winter and spring-summer, while in the Huasco salar the physical and chemical characteristics were related to the composition and abundance of the benthonic fauna. Thus, changes in the water volume of these systems would have repercussions in chemical and physical variables, altering the species assemblage and possibly the efficiency and stability of ecosystem functions. 相似文献
93.
Experimental verification of effective anisotropic crack theories in variable crack aspect ratio medium
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Jessica P. Henriques Jose J. S. de Figueiredo Leo K. Santos Daniel L. Macedo Icaro Coutinho Carolina B. da Silva Alberto L. Melo Mykel Sousa Felipe L. Azevedo 《Geophysical Prospecting》2018,66(1):141-156
Physical modelling of cracked/fractured media using downscaled laboratory experiments has been used with great success as a useful alternative for understanding the effect of anisotropy in the hydrocarbon reservoir characterization and in the crustal and mantle seismology. The main goal of this work was to experimentally verify the predictions of effective elastic parameters in anisotropic cracked media by Hudson and Eshelby–Cheng's effective medium models. For this purpose, we carried out ultrasonic measurements on synthetic anisotropic samples with low crack densities and different aspect ratios. Twelve samples were prepared with two different crack densities, 5% and 8%. Three samples for each crack density presented cracks with only one crack aspect ratio, whereas other three samples for each crack density presented cracks with three different aspect ratios in their composition. It results in samples with aspect ratio values varying from 0.13 to 0.26. All the cracked samples were simulated by penny‐shaped rubber inclusions in a homogeneous isotropic matrix made with epoxy resin. Moreover, an isotropic sample for reference was constructed with epoxy resin only. Regarding velocity predictions performed by the theoretical models, Eshelby–Cheng shows a better fit when compared with the experimental results for samples with single and mix crack aspect ratio (for both crack densities). From velocity values, our comparisons were also performed in terms of the ε, γ, and δ parameters (Thomsen parameters). The results show that Eshelby–Cheng effective medium model fits better with the measurements of ε and γ parameters for crack samples with only one type of crack aspect ratio. 相似文献
94.
Treistman Felipe Maceira Maria Elvira Pieiro Penna Dbora Dias Jardim Damzio Jorge Machado Rotunno Filho Otto Corra 《Stochastic Environmental Research and Risk Assessment (SERRA)》2020,34(2):331-353
Stochastic Environmental Research and Risk Assessment - The Brazilian Interconnected Power System is hydro dominated and characterized by large reservoirs presenting multi-year regulation... 相似文献
95.
Paulo?Roberto?Moura?de?CarvalhoEmail author Jo?o?Felipe?Coimbra?Leite?da?Costa Luiz?Gustavo?Rasera Luiz?Eduardo?Seabra?Varella 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(7):1805-1822
During exploration and pre-feasibility studies of a typical petroleum project many analyses are required to support decision making. Among them is reservoir lithofacies modeling, preferably using uncertainty assessment, which can be carried out with geostatistical simulation. The resulting multiple equally probable facies models can be used, for instance, in flow simulations. This allows assessing uncertainties in reservoir flow behavior during its production lifetime, which is useful for injector and producer well planning. Flow, among other factors, is controlled by elements that act as flow corridors and barriers. Clean sand channels and shale layers are examples of such reservoir elements that have specific geometries. Besides simulating the necessary facies, it is also important to simulate their shapes. Object-based and process-based simulations excel in geometry reproduction, while variogram-based simulations perform very well at data conditioning. Multiple-point geostatistics (MPS) combines both characteristics, consequently it was employed in this study to produce models of a real-world reservoir that are both data adherent and geologically realistic. This work aims at illustrating how subsurface information typically available in petroleum projects can be used with MPS to generate realistic reservoir models. A workflow using the SNESIM algorithm is demonstrated incorporating various sources of information. Results show that complex structures (e.g. channel networks) emerged from a simple model (e.g. single branch) and the reservoir facies models produced with MPS were judged suitable for geometry-sensitive applications such as flow simulations. 相似文献
96.
Michelle S. Cho Felipe Solano Neil R. Thomson Michael G. Trefry Daniel R. Lester Guy Metcalfe 《Ground Water Monitoring & Remediation》2019,39(3):23-39
Chaotic advection is a novel approach that has the potential to enhance contact between an injected reagent and target contaminants, and thereby improve the effectiveness of in situ treatment technologies. One configuration that is capable of generating chaotic advection is termed the rotated potential mixing (RPM) flow. A conventional RPM flow system involves periodically reoriented dipole flow driven by transient switching of pressures at a series of radial wells. To determine whether chaotic advection can be engineered using such an RPM flow system, and to assess the consequent impact on the spatial distribution of a conservative tracer, a series of field-scale experiments were conducted. These experiments involved the injection of a tracer in the center of a circular array of wells followed by either mixing using an engineered RPM flow system to invoke chaotic advection, or by natural processes (advection and diffusion) as the control. Pressure fluctuations from the mixing tests using the RPM flow system showed consistent peak amplitudes during injection and extraction at a frequency corresponding to the switching time, suggesting that the target hydraulic behavior was achieved with the time-dependent flow field. The tracer breakthrough responses showed oscillatory behavior at all monitoring locations during the mixing tests which indicated that the desired RPM flow was generated. The presence of chaotic advection was supported by comparisons to observations from a previous laboratory experiment using RPM flow, and the Fourier spectrum of the temporal tracer data. Results from several quantitative metrics adopted to demonstrate field-scale evidence of chaotic advection showed that mixing led to improved lateral tracer spreading and approximately uniform concentrations across the monitoring network. The multiple lines of evidence assembled in this proof-of-concept study conclusively demonstrated that chaotic advection can be engineered at the field scale. This investigation is a critical step in the development of chaotic advection as a viable and efficient approach to enhance reagent delivery. 相似文献
97.
Eduardo Eiji Maeda Antonio Roberto Formaggio Yosio Edemir Shimabukuro Gustavo Felipe Balué Arcoverde Matthew C. Hansen 《International Journal of Applied Earth Observation and Geoinformation》2009
The presented work describes a methodology that employs artificial neural networks (ANN) and multi-temporal imagery from the MODIS/Terra-Aqua sensors to detect areas of high risk of forest fire in the Brazilian Amazon. The hypothesis of this work is that due to characteristic land use and land cover change dynamics in the Amazon forest, forest areas likely to be burned can be separated from other land targets. A study case was carried out in three municipalities located in northern Mato Grosso State, Brazilian Amazon. Feedforward ANNs, with different architectures, were trained with a backpropagation algorithm, taking as inputs the NDVI values calculated from MODIS imagery acquired during five different periods preceding the 2005 fire season. Selected samples were extracted from areas where forest fires were detected in 2005 and from other non-burned forest and agricultural areas. These samples were used to train, validate and test the ANN. The results achieved a mean squared error of 0.07. In addition, the model was simulated for an entire municipality and its results were compared with hotspots detected by the MODIS sensor during the year. A histogram analysis showed that the spatial distribution of the areas with fire risk were consistent with the fire events observed from June to December 2005. The ANN model allowed a fast and relatively precise method to predict forest fire events in the studied area. Hence, it offers an excellent alternative for supporting forest fire prevention policies, and in assisting the assessment of burned areas, reducing the uncertainty involved in currently used methods. 相似文献
98.
Current surface conditions (strong oxidative atmosphere, UV radiation, low temperatures and xeric conditions) on Mars are considered extremely challenging for life. The question is whether there are any features on Mars that could exert a protective effect against the sterilizing conditions detected on its surface. Potential habitability in the subsurface would increase if the overlaying material played a protective role. With the aim of evaluating this possibility we studied the viability of two microorganisms under different conditions in a Mars simulation chamber. An acidophilic chemolithotroph isolated from Río Tinto belonging to the Acidithiobacillus genus and Deinococcus radiodurans, a radiation resistant microorganism, were exposed to simulated Mars conditions under the protection of a layer of ferric oxides and hydroxides, a Mars regolith analogue. Samples of these microorganisms were exposed to UV radiation in Mars atmospheric conditions at different time intervals under the protection of 2 and 5 mm layers of oxidized iron minerals. Viability was evaluated by inoculation on fresh media and characterization of their growth cultures. Here we report the survival capability of both bacteria to simulated Mars environmental conditions. 相似文献
99.
Andrea de Oliveira Cardoso Hilton Silveira Pinto Ana Maria Heuminski de Ávila Pedro Leite da Silva Dias Fabio Ricardo Marin Felipe Pilau 《Theoretical and Applied Climatology》2010,102(3-4):343-350
Weather conditions in critical periods of the vegetative crop development influence crop productivity, thus being a basic parameter for crop forecast. Reliable extended period weather forecasts may contribute to improve the estimation of agricultural productivity. The production of soybean plays an important role in the Brazilian economy, because this country is ranked among the largest producers of soybeans in the world. This culture can be significantly affected by water conditions, depending on the intensity of water deficit. This work explores the role of extended period weather forecasts for estimating soybean productivity in the southern part of Brazil, Passo Fundo, and Londrina (State of Rio Grande do Sul and Paraná, respectively) in the 2005/2006 harvest. The goal was to investigate the possible contribution of precipitation forecasts as a substitute for the use of climatological data on crop forecasts. The results suggest that the use of meteorological forecasts generate more reliable productivity estimates during the growth period than those generated only through climatological information. 相似文献