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Mostrando 13-24 de 621 artigos, teses e dissertações.
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13. Repeated geophysical measurements in dry and wet soil conditions to describe soil water content variability
ABSTRACT: There is an increasing interest in the application of geophysical surveys to assess the soil water content (SWC) variation in both spatial and temporal scales. In this work, a geophysical survey was carried out at an experimental farm in dry and wet conditions. We determined the SWC data measured with the gravimetric method, apparent electrical con
Sci. agric. (Piracicaba, Braz.). Publicado em: 20/12/2019
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14. VERTICAL ACCURACY ASSESSMENT OF THE PROCESSED SRTM DATA FOR THE BRAZILIAN TERRITORY
Abstract: This research aims to determine the vertical accuracy of the Interferometric Digital Elevation Model (DEM) obtained from the processed Shuttle Radar Topographic Mission (SRTM) data. The research compared the SRTM-GL1 (Shuttle Radar Topographic Mission-Global 1) with 30-meter resolution and the following 90-meter resolution models: (a) EMBRAPA; (b)
Bol. Ciênc. Geod.. Publicado em: 02/12/2019
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15. Frequency Selective Surface Properties of Microwave New Absorbing Porous Carbon Materials Embedded in Epoxy Resin
In this manuscript, the electromagnetic wave absorption properties of sustainable porous carbon composites were evaluated over the X-band frequency range (8.2 - 12.4 GHz). The porous carbon material was made from the byproduct of cellulose production and was used as additive on the development of radar absorbing material (RAM) composites. These porous carbon
Mat. Res.. Publicado em: 21/10/2019
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16. Iron oxide/titania composites for radar absorbing material (RAM) applications
Resumo Compósitos de óxido de ferro/titânia foram sintetizados pelo método de precipitação. A quantidade de óxido de ferro foi variada nos compósitos. Fase única (anatásio) foi obtida para a fração em massa de 0-20% e três fases (anatásio, magnetita e hematita) foram encontradas para as frações de 30% e 40% de óxido de ferro. O tamanho de cr
Cerâmica. Publicado em: 15/08/2019
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17. Use of hydrogeophysical data to determine the role of faults in the geometry of the Barreiras Aquifer, Brazil
Abstract Characterizing the geometry of an aquifer is fundamental for determining the locations of more productive wells. Commonly, flow and hydraulic parameters, such as transmissivity, are related to the thickness of the aquifer, which emphasizes the importance of regional hydrogeophysical characterization. Shuttle radar imagery, well profiles and geoelect
Braz. J. Geol.. Publicado em: 27/06/2019
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18. USE OF GROUND PENETRATING RADAR TO STUDY SPATIAL VARIABILITY AND SOIL STRATIGRAPHY
ABSTRACT Ground Penetrating Radar (GPR) is a geophysical method that uses electromagnetic waves to study subsurface structure in different fields such as geology, agriculture and civil engineering. The wave penetration in the soil is strongly controlled by the electrical conductivity of soil components such as clay, organic matter, and water. In this study,
Eng. Agríc.. Publicado em: 19/06/2019
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19. Three-Dimensional Reciprocal Invisibility Cloak with Multilayered Structure
Abstract We investigate a three-dimensional (3D) reciprocal invisibility cloak with a multilayered structure based on coordinate transformation theory and complementary media. There has been considerable research on invisibility cloaks such as the external cloak, which requires complex “anti-objects”, and closed cloaks of different shapes, in which the o
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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20. Water Basin Delimitation in a Relief Transition Region
ABSTRACT The objective of this work was to evaluate the performance accuracy of digital elevation models in delimiting a water basin located in the relief transition region between the São Francisco Plateau, São Franciscana Depression and the Espinhaço mountain range. Four digital elevation models with data from the Shuttle Radar Topographic Mission (SRTM
Floresta Ambient.. Publicado em: 30/05/2019
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21. Two-dimensional Determination of the Decision Boundary for a Radar Detection Method in the Moment Space
ABSTRACT: The radar detection with decision making in the moments space (DRACEC method) is based on a statistical analysis to determine the boundary between the background (absent target) and the anomaly (present target) classes. In this article, the boundary is taken as an ellipse and is calculated for two dimensions, emphasizing its geometric interpretatio
J. Aerosp. Technol. Manag.. Publicado em: 09/05/2019
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22. ANALYSIS OF THE TARGET DECOMPOSITION TECHNIQUE ATTRIBUTES AND POLARIMETRIC RATIOS TO DISCRIMINATE LAND USE AND LAND COVER CLASSES OF THE TAPAJÓS REGION
Resumo Este trabalho tem como objetivo analisar a capacidade dos atributos das técnicas de decomposição de alvos e dos atributos de retroespalhamento, provenientes das imagens polarimétricas do satélite ALOS/PALSAR-2, para discriminar as classes de uso e cobertura da terra na região da Floresta Nacional do Tapajós (FNT), estado do Pará. Três imagens
Bol. Ciênc. Geod.. Publicado em: 18/04/2019
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23. COMPARISON BETWEEN ABSOLUTE AND RELATIVE POSITIONAL ACCURACY ASSESSMENT - A CASE STUDY APPLIED TO DIGITAL ELEVATION MODELS
Resumo Este artigo apresenta um estudo comparativo entre os métodos absoluto e relativo para a avaliação de acurácia posicional altimétrica de Modelos Digitais de Elevação (MDE). Para o embasamento teórico desta pesquisa, foram apresentadas as definições de acurácia (exatidão) e precisão, bem como conceitos relativos à acurácia posicional abso
Bol. Ciênc. Geod.. Publicado em: 18/04/2019
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24. Effect of the Morphology and Structure on the Microwave Absorbing Properties of Multiwalled Carbon Nanotube Filled Epoxy Resin Nanocomposites
The current research shows the effect of structural and morphological differences of multilayer carbon nanotubes (CNT) on radar absorbing materials (RAM) performance. Two CNT samples, from different manufacturers, had their morphological and structural aspects investigated by XRD, SEM and SEM-FEG analyses. CNT/epoxy resin based nanostructured composites were
Mat. Res.. Publicado em: 16/07/2018