Navegando por Assunto "Density"

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Acesso aberto (Open Access)
Espécies arbóreas presentes na zona urbana de Altamira - Pará: índices espaciais e diversidade florística
(Universidade Federal do Pará, 2023-04-28) FEIO, Elnatan Ferreira; VELOSO, Gabriel Alves; http://lattes.cnpq.br/9757471213923099; HTTPS://ORCID.ORG/0000-0002-3655-4166; HERRERA, Raírys Cravo; http://lattes.cnpq.br/2153779197306503; https://orcid.org/0000-0002-9699-8359
In recent decades, the interest in studying the urbanization process in cities has become an extremely important subject, since this phenomenon is not planned. Disregarding regional differences, it becomes very distant to design more sustainable cities. One of the ways to achieve this sustainability is by promoting actions that encourage the insertion of afforestation achieving positive effects, such as the alleviation of the heat resulting from asphalting and the implementation of urban spaces. Thus, the promotion of afforestation in cities is one of the ways to minimize the adverse effects of climate in cities and improve the quality of life of the inhabitants. This work was carried out at the headquarters of the municipality of Altamira, located in the southwest region of Pará state. It was performed in three stages: (i) mapping of tree planting from manual vectorization to generate a cloud of points that enabled the analysis through the application of Kernel Density Statistics of the spatial distribution of tree species using calculation of environmental parameters for estimative, such as Vegetation Coverage Index (CVI) and Percentage of Vegetation Coverage (PCV); (ii) acquisition of remote sensing images with low cloudiness during the dry season, referring to the years 2011 and 2021 from the Satellites Landsat 5 Sensor TM and Landsat 8 Sensor Tirs, respectively, with images acquired on National Institute for Space Research (INPE) website; and (iii) survey of tree census in three neighborhoods of the city based on the largest coverage indices calculated in the first stage of the research to determine the Shannon-Weaver, Simpson, and Pielou Equability Indices. It was observed that the distribution of afforestation in Altamira is very variable and deficient, where most of the city's neighborhoods have a tree density deficit. The central neighborhoods are the most consolidated and have the highest densities of individuals. The PCV was 0.49% and the ICVH was 1.72 m² of canopy/inhabitant. Values under recommended by the United Nations Organization - UN and the Brazilian Society of Urban Arborization - SBAU. For the year 2011, the terrestrial thermal conditions in the city of Altamira varied between a minimum of 23.97°C and a maximum of 34.80°C, maintaining a constant around 32°C in the urbanized area, out of line with the maximum temperature 34°C was registered in a few points of the city, with an average temperature of 32.09°C at Centro neighborhood. In 2021, the temperature in Altamira reached a minimum of 23.35°C and a maximum of 33.89°C. The result of calculating the indices for the Premem, Jardim Uirapuru and Esplanada do Xingu neighborhoods showed the following values, respectively: a) Shannon-Weaver diversity (H'): 1.73, 1.81, 2.28; b) Pielou equability (J'): 0.65, 0.57, 0.72, and c) Simpson (C): 0.69, 0.71, 0.85, respectively. Qualitative analysis indicated that the higher the value of C, the lower the diversity of species, therefore, the highest distributed diversity is found in the Premem neighborhood. For the quantitative analysis, 793 tree individuals were cataloged, divided into 61 species, belonging to 40 botanical families which was found that 68% are exotic species and 32% are native. It is observed that the arrangement of the spatial distribution of urban trees did not follow the growth of the urban fabric, allowing the emergence of areas with low tree density which ended up in the urgency of a policy elaboration that contemplates green areas in our city, in order to humanizing roads and public areas and contributing to the regulation of the microclimate in Altamira, with positive effects on the well-being of the population and those who transit through here. Thus, this study has the necessary attributes to support urban planning in actions aimed at promoting comfort and the future attenuation of thermal sensation events, valuing the planting of native species to the detriment of exotic ones.
Acesso aberto (Open Access)
Post-imaging analysis of pressure prediction in productive sedimentary basins for oil and gas exploration
(Universidade Federal do Pará, 2015-05-26) VIEIRA, Wildney Wallacy da Silva; LEITE, Lourenildo Williame Barbosa; http://lattes.cnpq.br/8588738536047617
This thesis has several aspects related to the problem of basin modeling towards oil and gas exploration, and with two general divisions: parameter estimation, and pressure prediction. For the structure of this work, the first topic is related to velocity analysis and effective media, where estimated a distribution for the P wave velocity in time, the transformation to depth, and the use an effective model for the density and for the S wave velocity distributions. The reason for initially focusing on these estimations is because they represent one of the most basic information that one can have from the seismic domain, from where the other seismic parameters can be calculated, and from where the second part of this is totally based. The second topic is related to computing stress, strain and pressure distribution in the subsurface using the information from the P and S wave velocities and the density models, in order to localize areas of high and low pressures that act as natural suction pumps for the mechanics of oil and gas accumulation into productive zones and layers. We have highlighted this second part for the final work presentation, and call attention to the sensitivity of pressure mapping to the velocity and density variations. We also classify the first division as dedicated to the conventional seismic processing and imaging, and have clled the second division as post-imaging stressstrain-pressure prediction. As for the final aim of geophysics is to create images of the subsurface under different properties, the stress calculation only makes total sense for real data, and this makes mandatory the acquired seismic data be three component. As an important conclusion from the numerical experiments, we show that pressure does not have a trivial behavior, since it can decrease with depth and create natural pumps that are responsible for accumulating fluids. The theory of porous media is based on integral geometry, because this mathematical discipline deals with collective geometrical properties for real reservoirs. It was shown that such collective properties are namely for porosity, specific surface, average curvature and Gaussian curvature. For example, cracked media has, as a rule, small porosity, but very large specific surface area that creates anomalous high 𝛾 = 𝑣𝑆/𝑣𝑃 ratio, what means a negative 𝜎 Poisson coefficient. Another conclusion is related to calculating discontinuity in pressure between solid and fluid, what depends on the structure of pore space.
Acesso aberto (Open Access)
Variação temporal do fitoplâncton e dos parâmetros hidrológicos da zona de arrebentação da Ilha Canela (Bragança, Pará, Brasil)
(Sociedade Botânica do Brasil, 2009-12) SOUSA, Eliane Brabo de; COSTA, Vanessa Bandeira da; PEREIRA, Luci Cajueiro Carneiro; COSTA, Rauquírio André Albuquerque Marinho da
Seasonal and nyctemeral variations of the phytoplankton and hydrological parameters were studied at a fixed station (00º46'37.2"S-046º43'24.5"W) situated in Canela Island (Bragança-Pará) in September and December, 2004 and in March and June, 2005. Subsurface water samples were taken for qualitative and quantitative phytoplankton studies and to determine chlorophyll a concentrations. Simultaneously physical and chemical parameters were measured: salinity, temperature, pH, dissolved oxygen and percent of oxygen saturation. A total of 64 taxa belonging to Cyanophyta (one taxon), Bacillariophyta (54 taxa) and Dinophyta (nine taxa) were identified. Chlorophyll a concentrations ranged from 4.67 mg m-3 (dry season), to 5.44 mg m-3 (rainy season) and follow phytoplankton densities, which were higher during the rainy period (mean values of 1,870 x 103 cell L-1). Phytoflagellates quantitatively dominated the local phytoplanktonic community followed by diatoms. Dimeregramma minor and Skeletonema sp. were abundant and ve