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Search Results: 1 - 10 of 401689 matches for " Dalton M. Valeriano "
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Simula o do saldo de radia o na Serra da Mantiqueira Simulation of net radiation in the Mantiqueira mountain
Pabricio M. O. Lopes,Dalton M. Valeriano,Bernardo B. da Silva,Geber B. de A. Moura
Revista Brasileira de Engenharia Agrícola e Ambiental , 2013,
Abstract: A influência do desmatamento da Mata Atlantica sobre o microclima da Serra da Mantiqueira ainda n o é totalmente compreendida. Para conhecer as consequências do desmatamento sobre o clima serrano é necessário realizar estudos sobre o balan o de radia o na superfície. A falta de dados possibilita conjugar imagens de satélite com dados meteorológicos em um Sistema de Informa o Geográfica na determina o do balan o de radia o. O presente estudo teve por objetivo avaliar o modelo MTCLIM em dias de céu claro ou nublado para simular o balan o de radia o na Serra da Mantiqueira, divisa entre os estados de S o Paulo, Minas Gerais e Rio de Janeiro, Brasil. Imagens diárias, semanais e dezesseis dias do sensor MODIS disponíveis em 2003 foram utilizadas em rotinas específicas do MTCLIM. Alvos específicos foram selecionados para avaliar o comportamento do balan o de radia o. Observou-se que o balan o de radia o acompanhou a topografia local e é influenciado pelo tipo de uso da terra. Conclui-se que a temperatura da superfície contribui para aumentar a temperatura do ar implicando em diminui o do balan o de radia o sobre pastagem. O modelo MTCLIM demonstrou boa correla o para a temperatura do ar (R2 = 0,82) e para a radia o solar global (R2 = 0,71). The influence of deforestation of the Atlantic Forest on the microclimate of the mountain Mantiqueira is not yet fully understood. To understand the consequences of deforestation on the highland climate research is needed about the surface radiation balance. The lack of data allows combining satellite images with meteorological data in a Geographic Information System in determining the radiation balance. The study aimed to evaluate the MTCLIM model in cloudless days or cloudy sky and simulate the radiation balance in the Mantiqueira mountain, between S o Paulo, Minas Gerais and Rio de Janeiro, Brazil. Daily images, weekly and sixteen days MODIS available in 2003 were used in specific routines from MTCLIM. Specific targets were selected to evaluate the behavior of the radiation balance. It was observed that the radiation balance followed the local topography and is influenced by the type of land use. It follows that the surface temperature contributes to elevate the air temperature, resulting in lesser radiation balance on pasture. The MTCLIM model showed good correlation for air temperature (R2 = 0.82) and solar radiation (R2 = 0.71).
Near real time detection of deforestation in the Brazilian Amazon using MODIS imagery
Yosio E. Shimabukuro,Valdete Duarte,Liana O. Anderson,Dalton M. Valeriano
Ambiente e água : An Interdisciplinary Journal of Applied Science , 2006,
Abstract: The objective of this paper is to provide near real time information about deforestation detection (DETER) in the entire Brazilian Amazon using MODIS high temporal resolution images. It is part of the operational deforestation monitoring project to estimate the annual deforestation rate in the Brazilian Amazon (PRODES). A rapid deforestation detection method was designed to support land use policies in this region. In order to evaluate the proposed method a test site was selected covering a Landsat ETM+ scene (227/68) located in Mato Grosso State. For this purpose a multitemporal series of MODIS surface reflectance images (MOD09) and the corresponding ETM+ images from June to October 2002 were analyzed. It was found that small deforested areas (lower than 15 ha) were detected by MODIS images with lower accuracy when compared with ETM+ images. As the deforested areas increase MODIS and ETM+ results tend to converge. This procedure showed to be adequate to operationally detect and monitor deforested areas and has been used since 2004 as part of a government plan to control the Amazon deforestation.
Pabrício Marcos Oliveira Lopes,Dalton de Morisson Valeriano
Revista Geográfica Acadêmica , 2009,
Abstract: This work evaluates the Mountain Climate Simulator (MTCLIM) in the extrapolation of minimum and maximum daily air temperatures in the region of the Serra of Mantiqueira, Brazil, using data from DCP (Automatic Data Collection Platform) in different sky conditions in the year of 2003. Comparison between simulated results and data of DCP were conducted though linear regression analysis. Data from DCP localized in city from Queluz in S o Paulo were used to extrapolation minimum and maximum daily air temperature in 271 points of the sierra. The results obtained to locations with the same altitude showed that the model overestimated maximum daily (Tx) and underestimated minimum (Tn) independent of sky conditions. The locations different elevations and clear skies, the model estimated the Tx with good agreement and an error of 1.4°C. With the inclusion of cloud cover, the model improved the estimate of Tx, but the error increased to 1.7°C. The presence of clouds reduced the spatial distribution of maximum monthly in the mountain. The absence of clouds caused decrease in the minimum monthly. The model can be applied to station at the same altitude. The regime monthly of temperature presents similar regime to the regional seasonal variability.
Mapeamento da declividade em microbacias com Sistemas de Informa??o Geográfica
Valeriano, Márcio de M.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2003, DOI: 10.1590/S1415-43662003000200020
Abstract: the objective of this study was to establish optimal procedures for the calculation of watershed slope using geographical information systems (gis). the tests evaluated the geoprocessing methods according to regression analyses with a cartoghaphically hand-measured data set. statistical and geostatistical analyses showed the high variability of slope values, turning cartographic generalization techniques inadequate. field measured slopes showed low agreement with cartographic and gis estimated values. it was concluded that slope angle calculations require high resolution of the digital terrain model (dtm), interpolated through kriging. smoothing the dtm decreased the slope determination accuracy, while increased correlation when applied to the slope image itself. adjustment factors were calculated for different conditions of resolution and smoothing tested. the estimate errors in the developed method were evaluated by mapping the standardized residues.
Curvatura vertical de vertentes em microbacias pela análise de modelos digitais de eleva??o
Valeriano, Márcio de M.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2003, DOI: 10.1590/S1415-43662003000300022
Abstract: this study aims at the development and evaluation of a simple approach to map profile curvature from digital elevation models (dem) with basic resources of geographical information systems (gis). this method is based on local 3x3 pixel windows and designed to perform geometrically the second order derivative through the downslope profile. contour-based kriged dem of six watersheds from different terrain types and with varied data specifications were used for the tests. to program universally flexible procedures, the curvature calculation required the dem spatial resolution as one of the inputs, so as to calculate a comparable absolute value, with slope difference (in percentage ratio) per horizontal distance (100 m) as unit. the classification of slope direction in octants was used to control the overlapping derivation results calculated towards the eight neighbor pixels of each window position. the placement of boundaries with guidance of visual analysis of known slope forms assisted the establishment of arbitrary curvature thresholds for the slope profile classes (concave, convex and rectilinear).
Estimativa de área de vegeta??o secundária na Amaz?nia Legal Brasileira
Almeida, Cláudio Aparecido;Valeriano, Dalton Morisson;Escada, Maria Isabel Sobral;Rennó, Camilo Daleles;
Acta Amazonica , 2010, DOI: 10.1590/S0044-59672010000200007
Abstract: secondary vegetation has many relevant functions to the ecosystems such as atmospheric carbon fixation , maintenance of biodiversity, establishment of connectivity among forest remnants, maintenance of hydrological regime, and restoration of soil fertility. the objective of this work is to estimate the area occupied by secondary vegetation in the brazilian legal amazon (bla) for 2006 using a sampling scheme. the sampling is based on a stratified approach according to the degree of deforestation observed in the 229 tm-landsat scenes that cover the bla. thus, 26 scenes were selected for 2006 and distributed into seven strata, according to their degree of deforestation, in which secondary vegetation areas were mapped. a regression model was constructed to estimate secondary vegetation area in the remaining images using deforestation area, hydrographic area, agrarian structure , and area of conservation units, as independent variables. the regression analysis found an adjusted r2 of 0.84 and positive coefficients for the proportion of hydrography in the image (2.055) and for the agrarian structure (0.197), while negative coefficients for the degree of deforestation in the image (-0.232) as well as for the proportion of conservation unity(-0.262). using the multivariate regression model, an area of 131,873 km2 of secondary vegetation was estimated for the year of 2006. applying a monte carlo simulation we estimated an uncertainty of approximately 12,445 km2 .
Influência da temperatura do ar de secagem e da concentra??o de agente carreador sobre as propriedades físico-químicas do suco de a?aí em pó
Tonon, Renata Valeriano;Brabet, Catherine;Hubinger, Míriam Dupas;
Ciência e Tecnologia de Alimentos , 2009, DOI: 10.1590/S0101-20612009000200034
Abstract: the objective of this work was to study the influence of inlet air temperature and maltodextrin concentration on the physicochemical properties of a?ai juice powder produced by spray drying. the process was carried out in a mini spray dryer and the maltodextrin 10de was used as carrier agent. inlet air temperature varied from 138 to 202 °c and maltodextrin concentration varied from 10 to 30%. the characteristics analyzed were: moisture content, hygroscopicity, anthocyanin retention, color, particle size distribution, and morphology. the increase in the temperature resulted in particles with larger size, less moisture content, more hygroscopy and with lower anthocyanin retention, besides promoting a reduction in the color parameter l* and in the hue angle h*. the increase of maltodextrin concentration resulted in less hygroscopy, particles with larger size, , with higher luminosity (l*), lower c* values and higher h* values. with respect to morphology, the increase in the temperature led to the formation of a great number of particles with smooth surface, which is due to the higher heat transfer and, consequently, to the faster formation of a membrane around the atomized drop.
Estudo da desidrata??o osmótica de tomate em solu??es ternárias pela metodologia de superfície de resposta
Tonon, Renata Valeriano;Baroni, Alessandra Faria;Hubinger, Míriam Dupas;
Ciência e Tecnologia de Alimentos , 2006, DOI: 10.1590/S0101-20612006000300036
Abstract: the objective of this work was to study the influence of temperature (20 - 40 °c), solution composition (0% nacl/65% sucrose - 10% nacl/55% sucrose) and agitation level (0 - 1000 rpm), on the osmotic dehydration of tomato's halves. the process was carried out in a jacketed tank connected to a thermostatic bath, and osmotic solution agitation was promoted by a mechanical stirrer and measured by a digital tachometer. results were analyzed through response surface methodology, according to a 23 factorial experimental design. water loss, salt and sucrose gain and final water activity of the product were positively influenced by temperature and by increasing salt content on the solution. agitation influenced only on water loss, indicating that in this case, mass transfer is not governed only by a diffusion internal mechanism. equilibrium proximity reached in each test was verified through the relationship between solution and samples water activities. the samples processed in solutions with higher salt content seemed to be more distant of equilibrium, after 3 hours of process.
Suaviza??o da declividade em fun??o da resolu??o da imagem em sistema de informa??o geográfica
Cavalli, Antonio Carlos;Valeriano, Márcio de Morisson;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2000, DOI: 10.1590/S1415-43662000000200028
Abstract: this paper presents a methodology to minimize the slope softening effect caused by pixel variations in the digital elevation model (dem) interpolation used in geographic information systems. the studied area is part of rio piracicaba (s?o paulo state, brazil) watershed, located in a very steep site in order to point out the high variability slope aspects of the region. slope maps with 100, 125, 200 and 250 m pixels were produced. transects were overlayed on them to provide data for correlation analysis. the method confirmed the high variability among the slope maps. furthermore, alternatives to avoid the slope softening effect and data precision losses were established.
Estimativa de volume de madeira em plantios de Eucalyptus spp. utilizando dados hiperespectrais e dados topográficos
Canavesi, Vanessa;Ponzoni, Flávio Jorge;Valeriano, Márcio Morisson;
Revista árvore , 2010, DOI: 10.1590/S0100-67622010000300018
Abstract: the availability of orbital hyperspectral data has brought new perspectives to both academic and corporative sectors solving demands in forestry science. the main objective of this work was to evaluate the potential of hyperion eo-1 hyperspectral data to quantify the biophysical timber volume in eucalyptus spp stands and the effect of hill shading in that quantification. for this, the correlations between spectral data and timber volume were performed following the use of multiple linear regression models as the descriptors of the relationships established. the relief effect on the eucalyptus spp. canopy reflectance was taken into account. the hyperion eo-1 data were converted to brf surface values, which were considered the basis of the entire work. the study area was located in the municipality of cap?o bonito (the state of s?o paulo, brazil) and included eucalyptus spp. stands managed by the votorantim papel e celulose company (vcp). spectral samples were collected in different topographic conditions. in the establishment of the relationship with timber volume, the vegetation indices estimated using hyperspectral data resulted in models with higher r2 when considering the topographic illumination effect, showing higher applicability potential of this data.
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