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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Using remote sensing to monitor herbicide injury and biomass of waterhyacinth

Robles, Wilfredo 08 August 2009 (has links)
Aquatic vegetation plays an important role in the ecological interactions and processes within a water body. However, the presence of the invasive exotic aquatic plant species, waterhyacinth [Eichhornia crassipes (Mart.) Solms], negatively affects those interactions as well as interfering with water use for recreation and navigation. An implemented management plan for waterhyacinth control relies on the use of herbicides. Efficacy is commonly assessed using visual injury and control ratings as well as estimating biomass. The problem is that those approaches are labor intensive only assessing single points throughout the entire water body. Therefore, technology like remote sensing, which is the focus of this research, is recommended as an additional tool to assess implemented management plans. Studies were conducted in a mesocosm research facility to evaluate the relationship between simulated spectral bands 3, 4, 5, and 7 Landsat 5 TM and waterhyacinth treated with the herbicides imazapyr and glyphosate. Results indicate that injury is better detected and predicted with band 4 and that relationship is negative when either herbicide was used. However, prediction is better when plants have developed sufficient injury to influence the spectral response of band 4. In the second study, the biomass of waterhyacinth was estimated using the Normalized Difference Vegetation Index (NDVI) using simulated data from Landsat 5 TM. This study was conducted over natural populations of waterhyacinth in Lakes Columbus and Aberdeen, MS over two growing seasons. Results indicate that the use of NDVI alone is a weak predictor of biomass; however, its combination with morphometric parameters like leaf area index enhanced predictive capabilities.In order to assess field herbicide treatments for waterhyacinth control and its consequent impact on native aquatic vegetation, lake-wide surveys were performed in Lake Columbus, MS using a point-intercept method. The herbicide assessed was 2,4-D which was applied aerially and by boats. Point-intercept surveys in a 400 by 400 grid of points aided with global positioning system (GPS) were performed before and after herbicide treatments. Obtained results indicate that the frequency of occurrence of waterhyacinth significantly decreased after herbicide treatments which consequently led to the reestablishment of native aquatic vegetation on the system.
32

Capabilities of LANDSAT-5 Thematic Mapper (TM) data in studying soybean and corn crop variables

Thenkabail, Prasad Srinavasa January 1992 (has links)
No description available.
33

Production of Linear Alpha Olefins via Heterogeneous Metal-OrganicFramework (MOF) Catalysts

Alalouni, Mohammed R. 12 1900 (has links)
Linear Alpha Olefins (LAOs) are one of the most important commodities in the chemical industry, which are currently mainly produced via homogenous catalytic processes. Heterogeneous catalysts have always been desirable from an industrial viewpoint due to their advantages of low operation cost, ease of separation, and catalyst reusability. However, the development of highly active, selective, and stable heterogeneous catalysts for the production of LAOs has been a challenge throughout the last 60 years. In this dissertation, we designed and prepared a series of heterogeneous catalysts by incorporating structural moieties of homogenous benchmark catalysts into metal-organic-frameworks (MOFs), aiming to provide a feasible solution to this long-standing challenge. First, we reviewed the background and state of the art of this field and put forward the main objectives of our research. Then, we thoroughly discussed a novel heterogeneous catalyst (Ni-ZIF-8) that we developed for ethylene dimerization to produce 1-butene, focusing on its designed principle, detailed characterizations, catalytic performance evaluation, and reaction mechanisms. Ni-ZIF-8 exhibits an average ethylene turnover frequency greater than 1,000,000 h$^{-1}$ (1-butene selectivity >85%), far exceeding the activities of previously reported heterogeneous and many homogenous catalysts under similar conditions. Compared with homogenous nickel catalysts, Ni-ZIF-8 has significantly higher stability and showed constant activity during four hours of continuous reaction for at least two reaction cycles. The combination of isotopic labeling studies and Density Functional Theory calculations demonstrated that ethylene dimerization on Ni-ZIF-8 follows the Cossee-Arlman mechanism, and that the full exposure and square-planer coordination of the nickel sites account for the observed high activity. After that, we further optimized the Ni-ZIF-8 catalytic system from the perspective of practical applications. We achieved double productivity of 1-butene by optimizing the synthetic conditions and explored its usability and performances under solvent-free conditions. Then, we extended our catalyst design concept to prepare heterogeneous catalysts comprising other metals and MOFs, which provided a suitable platform for studying the effects of the metallic center and coordination environment on the catalytic production of LAOs. Finally, we gave our perspectives on the further development of heterogeneous catalysts for the production of LAOs.
34

An analysis of player position group, height, weight, and relative body weight and their relationship to scores on the Functional Movement Screen(TM)

Krackow, Michael Stuart 10 December 2001 (has links)
Sports medicine professionals are continuously attempting to keep the incidence of injuries down. One way to accomplish this is to employ preventive methods that identify athletes who are at a greater risk of becoming injured prior to the start of the athletic season. The Functional Movement Screen™ (FMS) is a screening method that attempts to identify those individuals at risk of sustaining injuries by determining deficits in athletes' mobility and stability. This is an area of great conflict because athletic injuries result from many factors, not only in mobility and stability weaknesses. Therefore, it must first be determined whether deficient scores on the FMS are the result of the proposed weakness, or rather other potential risk factors. Functional Movement Screen™ scores were collected from 136 collegiate Division 1-A football players from three athletic programs. The scores were separated into one of three groups based upon the position played by each subject: (1) skill group, (2) combo group, and (3) line-of-scrimmage group. Data were also collected on each subject's height, weight, and relative body weight (BMI). The results of the ANOVA and Tukey HSD showed that there was a significant difference p < 0.05 between the line-of-scrimmage group and the skill group, as well as between the line-of-scrimmage group and the combo group. No significant difference was demonstrated between the combo group and the skill group. The results of the Pearson Correlation demonstrated a significant negative relationship p < 0.05 between the height of an athlete and the score received on the FMS. Significant negative relationships p < 0.01 were shown between the weight of an athlete and the score received on the FMS, as well as the relative body weight (BMI) and the athletes' score on the FMS. The results suggest that the score an athlete receives on the FMS may not reflect mobility and stability deficiencies because other factors affect the outcome of the scores. Therefore, at the present time, the FMS may not be a reliable tool by itself for identifying athletes who are at a greater risk of sustaining non-contact types of injuries. / Ph. D.
35

Application of Spectral Change Detection Techniques to Identify Forest Harvesting Using Landsat TM Data

Chambers, Samuel David 12 August 2002 (has links)
The main objective of this study was to determine the spectral change technique best suited to detect complete forest harvests (clearcuts) in the Southern United States. In the pursuit of this objective eight existing change detection techniques were quantitatively evaluated and a hybrid method was also developed. Secondary objectives were to determine the impact of atmospheric corrections applied before the change detection, and the affect post-processing methods to eliminate small groups of misclassified pixels ("salt and pepper" effect) had on accuracy. Landsat TM imagery of Louisa County, Virginia was acquired on anniversary dates in both 1996 and 1998 (Path 16, Row 34), clipped to the study area boundary, and registered to one another. Previous to the change detection exercise, two levels of atmospheric corrections were applied to the imagery separately to produce three data sets. The three data sets were evaluated to determine what level of pre-processing is necessary for harvest change detection. In addition, eight change detection techniques were evaluated: 1) the 345 TM band differencing, 2) 35 TM band differencing, 3) NDVI differencing, 4) principal component 1 differencing, 5) selection of a change band in a multitemporal PCA, 6) tasseled cap brightness differencing, 7) tasseled cap greenness differencing, and 8) univariate differencing using TM band 7. A hybrid method that used the results from the eight previous techniques was developed. After performing the change detection, majority filters using window sizes of 3x3 pixels, 5x5 pixels, and 7x7 pixels were applied to the change maps to determine how eliminating small groups of misclassified pixels would affect accuracies. Accuracy assessments of the binary (harvested or not harvested) change maps were used to evaluate the accuracies of the various methods described using 256 validation points collected by the Virginia Department of Forestry. The atmospheric corrections did not seem to significantly benefit the change detection techniques, and in some cases actually degraded accuracies. Of the eight techniques applied to the original dataset, univariate differencing using TM band 7 performed the best with a 90.63% overall accuracy, while Tasseled Cap Greenness returned the worst result with an overall accuracy of 78.91%. Principal component 1 differencing and 35 differencing also performed well. The hybrid approach returned good results, but at its best returned an overall accuracy of 90.63%, matching the TM band 7 method. The majority filters using the 3x3 and 5x5 window sizes increased the accuracy in many cases, while the majority filter using the 7x7 window size degraded overall accuracy. / Master of Science
36

Preparação e caracterização de cerâmicas supercondutoras nos sistemas Y-Ba-Cu-O e Tm-Ba-Cu-O / Preparation and characterization of superconducting ceramics in the system Y-Ba-Cu-O and Tm-Ba-Cu-O

Martin, Airton Abrahao 25 August 1988 (has links)
Neste trabalho estudamos a influencia da temperatura e tempo de reação e sinterização na preparação de amostras cerâmicas supercondutoras pelo método de reação no estado sólido. Os resultados indicam claramente que algumas propriedades destes supercondutores, tais como: temperatura crítica (Tc), susceptibilidade magnética (X), resistividade (&#961), microestruturas, densidade e porosidade aparente, sofrem forte influencia das condições de tratamento térmico. Foram preparadas várias amostras dos sistemas YBa2Cu3O6.5+x e TmBa2Cu3O6.5+x, sendo que a temperatura e tempo ideal de reação encontrados foram de 950&#176C por 6 horas e 925&#176C por 48 horas, respectivamente; ambas tratadas em fluxo de oxigênio. A caracterização destas amostras foram feitas pelas técnicas de difração de raios-x, técnica de quatro-pontas (medida da variação da resistividade pela temperatura), ponte de Hartshorn (para a medida da variação da susceptibilidade magnética pela temperatura), microscopia eletrônica de varredura (para análise das microestruturas) e método de imersão (para a medida da densidade e porosidade aparente). A maior temperatura crítica encontrada foi de aproximadamente 94K para YBa2Cu3O6.5+x e de aproximadamente 91K para o TmBa2Cu3O6.5+x / The influence of the temperature and time in the reaction and sinterization of superconducting ceramics prepared by a solid state reaction was determined. The results clearly showed that some of its properties, such as critical temperature (Tc), magnetic susceptibility (X), resistivity (&#961), microstructure, apparent density, and porosity undergo a strong influence of the preparation conditions. Some samples in the YBa2Cu3O6.5+x and TmBa2Cu3O6.5+x systems were prepared. The ideal reaction temperature and time were 950&#176C for 6 hours and 925&#176C for 48 hours, respectively. Both annealed in O2 flow. The sample characterization was made by using X-ray diffraction, standard four probe (measures the variation of resistivity versus temperature), Bridge of Hartshorn (the variation of susceptibility versus temperature), scanning electron micrograph (microstructure analysis), and immersion method (measures the apparent density and porosity). The greatest critical temperature was approximately 94K for YBa2Cu3O6.5+x and 91K for TmBa2Cu3O6.5+x
37

Tradução e adaptação cultural do instrumento: “The SACS TM Instrument”

Silveira, Néria Invernizzi da 16 March 2018 (has links)
Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2018-07-11T12:30:48Z No. of bitstreams: 1 Néria Invernizzi da Silveira.pdf: 1566170 bytes, checksum: ce5da5f364608bd9ea3f5d9d42dd87de (MD5) / Made available in DSpace on 2018-07-11T12:30:48Z (GMT). No. of bitstreams: 1 Néria Invernizzi da Silveira.pdf: 1566170 bytes, checksum: ce5da5f364608bd9ea3f5d9d42dd87de (MD5) Previous issue date: 2018-03-16 / Introduction: The skin around the ostomy should be evaluated constantly because of the risk of having its integrity impaired and there is no instrument validated in Brazil for assessment and classification of the lesions and topographic location. Objective: To carry out the cultural adaptation of "The SACS™ Instrument" for use in Brazil and assess content validity, inter-observer reliability and evaluate the educational dimension to the understanding of this instrument. Method: This is a methodological study with a quantitative and qualitative approach. The cultural adaptation was elaborated by four translators in the translation and back-translation phases and its summaries were compiled by the author. The content validity index (CVI) was analyzed by seven judges for semantic, idiomatic, cultural and conceptual equivalences. The formula for calculating the CVI was the addition of the answers, divided by the total number of answers. Inter-observer reliability came from the investigation of 41 photographs, carried out by two nurses who specialize in stomatherapy and the values were presented in percentage and with the weighted kappa coefficient (K). To achieve instrument validity a focus group strategy was used, with eight students from year four of the undergraduate nursing program. Result: The result obtained for SACS™ Instrument was IVC=1. Reliability for the evaluation and classification of the lesions presented agreement of 41.18% and K = 0.2444, and for topographic location resulted in 46.67% and K = 0.3151. Another measure of interobserver agreement was the level of statistical significance that presented p <0.001 and was found to be extremely significant. Discussion: The process of translation and cultural adaptation was developed with the scientific rigor of the research objective. IVC = 1 was the same as that in a study in Turkey. In Italy and the USA, IVC = 0.91 and IVC = 0.94, respectively, demonstrated the viability in clinical practice, but with specific training. Conclusion: The SACSTM instrument was translated and adapted to Brazilian Portuguese culture and meant to be an internationally standardized tool and useful in clinical practice for the evaluation, classification, topographic location of peristomial lesions, certifying reliable results and that met the objectives of this study / Introdução: A pele ao redor da estomia deve ser avaliada constantemente pois possui risco de perda de sua integridade e não há instrumento no Brasil para a avaliação, classificação e localização topográfica destas lesões. Objetivo: Este estudo objetivou realizar e adaptação cultural do “The SACSTM Instrument” para o Brasil, avaliar o índice de validade de conteúdo (IVC) e a confiabilidade interobservadores. Método: É um estudo metodológico com abordagem quantitativa. A adaptação cultural foi desenvolvida por quatro tradutores, sendo dois para a tradução e dois para a retrotradução. O IVC das equivalências de semântica, idiomática, cultural e conceitual foram analisadas por sete juízes e a versão final foi elaborada pela pesquisadora. A concordância interobservadores ocorreu pela análise de quarenta e uma fotografias por dois ET. Resultado: O SACSTM obteve IVC=1. A confiabilidade, para a avaliação e classificação das lesões apresentou concordância de 41,18% e K=0,2444, e para localização topográfica resultou em 46,67% e K=0,3151. Outra medida de concordância interobservadores foi o nível de significância estatística que apresentou p<0,001 concluindo ser extremamente significante. Discussão: O processo de tradução e adaptação cultural foi desenvolvido com o rigor científico do objetivo da pesquisa. O IVC =1 foi o mesmo que ocorreu em um estudo da Turquia. Na Itália e EUA resultou respectivamente em IVC = 0,91 e IVC = 0,94, demonstrando a viabilidade na prática clínica, porém com capacitação específica. Conclusão: O instrumento SACSTM foi traduzido e adaptado para a cultura do português do Brasil e significou ser uma ferramenta padronizada internacionalmente e de utilidade na prática clínica para a avaliação, classificação, localização topográfica das lesões periestomias, certificando resultados fidedignos e que atendeu os objetivos deste estudo
38

Imagens multitemporais do Landsat TM como estratégia no apoio ao levantamento pedológico / Landsat TM multi-temporal images as strategy for pedological survey

Gallo, Bruna Cristina 10 December 2015 (has links)
A espacialização de atributos dos solos é necessária com vistas ao planejamento e monitoramento do solo. As imagens do satélite Landsat 5 Thematic Mapper (TM) são utilizadas em estudos relacionados aos recursos naturais por fornecerem informações da superfície das terras em áreas amplas e de difícil acesso. Nesse trabalho objetivou-se gerar uma imagem multitemporal de solo exposto através de imagens de satélite e, com ela, mapear atributos da superfície do solo. A área de estudo é a região de Piracicaba, SP, onde foram selecionadas treze imagens do Landsat TM. Amostras da camada mais superficial dos solos foram coletadas em 740 pontos, e nelas analisados vários atributos do solo. Por meio da reflectância espectral dos objetos das imagens de satélite foram obtidas informações de solo exposto e eliminados outros alvos. As imagens foram adquiridas em série histórica e sobrepostas, gerando uma composta final com solo exposto. Os atributos do solo que obtiveram boa correlação com as bandas dessa imagem foram quantificados por meio da técnica de regressão multivariada e espacializados. Mapas pré-existentes de geologia e pedologia auxiliaram no entendimento da variabilidade espacial da textura e cor dos solos na paisagem. A taxa de variação do solo exposto em uma imagem individual variou de 7 a 20 %, enquanto a unificada atingiu 53 % da área total. Valores de reflectância entre as bandas TM3 e TM4 contrapostos representando a linha do solo e curva espectral média de espectros de amostras de solos obtidas em laboratório apresentaram semelhança com as de satélite. Entre os atributos estudados, a argila obteve a melhor correlação com R2 de 0,75, erro baixo e RPD acima de 2. Outros atributos relacionados com a argila também obtiveram boa correlação, como matéria orgânica (MO) e capacidade de troca de cátions (CTC) com R2 de 0,4 e 0,34 respectivamente. / The knowledge of spatial distribution of soil attributes is necessary for soil planning and monitoring. Landsat 5 Thematic Mapper (TM) images are used in studies related to natural resources for providing the land surface information in large areas and in areas of difficult access. This work aimed to create a multi-temporal image of bare soil through satellite scenes and map soil attributes from the surface. The study area is located in Piracicaba region, SP, where thirteen Landsat TM scenes were selected. Samples of the soil superficial layer were collected at 740 points, and several soil properties were analyzed. Spectral reflectance of different objects from satellite images was obtained and only exposed soil information was selected. Images were acquired in historical series and overlapped, generating a final composed image with bare soil. Soil attributes that presented good correlation with the bands were quantified by multivariate regression and mapped. Pre-existing maps of geology and soil helped in understanding soil texture spatial variability and color in the landscape. The soil variation rate in an individual exposed image ranged from 7 to 20%, while the unified reached 53% of the total area. Obtained values of reflectance between TM3 and TM4 bands representing the soil line and average spectral curve of laboratory soil samples were similar to the satellite ones. Among the soil attributes studied, clay presented the best correlation with R2 value of 0.75, low error and RPD value above 2.0. Other attributes related to clay also presented good correlation, such as organic matter (OM) and cation exchange capacity (CEC) with R2 values of 0.4 and 0.34 respectively.
39

Imagens multitemporais do Landsat TM como estratégia no apoio ao levantamento pedológico / Landsat TM multi-temporal images as strategy for pedological survey

Bruna Cristina Gallo 10 December 2015 (has links)
A espacialização de atributos dos solos é necessária com vistas ao planejamento e monitoramento do solo. As imagens do satélite Landsat 5 Thematic Mapper (TM) são utilizadas em estudos relacionados aos recursos naturais por fornecerem informações da superfície das terras em áreas amplas e de difícil acesso. Nesse trabalho objetivou-se gerar uma imagem multitemporal de solo exposto através de imagens de satélite e, com ela, mapear atributos da superfície do solo. A área de estudo é a região de Piracicaba, SP, onde foram selecionadas treze imagens do Landsat TM. Amostras da camada mais superficial dos solos foram coletadas em 740 pontos, e nelas analisados vários atributos do solo. Por meio da reflectância espectral dos objetos das imagens de satélite foram obtidas informações de solo exposto e eliminados outros alvos. As imagens foram adquiridas em série histórica e sobrepostas, gerando uma composta final com solo exposto. Os atributos do solo que obtiveram boa correlação com as bandas dessa imagem foram quantificados por meio da técnica de regressão multivariada e espacializados. Mapas pré-existentes de geologia e pedologia auxiliaram no entendimento da variabilidade espacial da textura e cor dos solos na paisagem. A taxa de variação do solo exposto em uma imagem individual variou de 7 a 20 %, enquanto a unificada atingiu 53 % da área total. Valores de reflectância entre as bandas TM3 e TM4 contrapostos representando a linha do solo e curva espectral média de espectros de amostras de solos obtidas em laboratório apresentaram semelhança com as de satélite. Entre os atributos estudados, a argila obteve a melhor correlação com R2 de 0,75, erro baixo e RPD acima de 2. Outros atributos relacionados com a argila também obtiveram boa correlação, como matéria orgânica (MO) e capacidade de troca de cátions (CTC) com R2 de 0,4 e 0,34 respectivamente. / The knowledge of spatial distribution of soil attributes is necessary for soil planning and monitoring. Landsat 5 Thematic Mapper (TM) images are used in studies related to natural resources for providing the land surface information in large areas and in areas of difficult access. This work aimed to create a multi-temporal image of bare soil through satellite scenes and map soil attributes from the surface. The study area is located in Piracicaba region, SP, where thirteen Landsat TM scenes were selected. Samples of the soil superficial layer were collected at 740 points, and several soil properties were analyzed. Spectral reflectance of different objects from satellite images was obtained and only exposed soil information was selected. Images were acquired in historical series and overlapped, generating a final composed image with bare soil. Soil attributes that presented good correlation with the bands were quantified by multivariate regression and mapped. Pre-existing maps of geology and soil helped in understanding soil texture spatial variability and color in the landscape. The soil variation rate in an individual exposed image ranged from 7 to 20%, while the unified reached 53% of the total area. Obtained values of reflectance between TM3 and TM4 bands representing the soil line and average spectral curve of laboratory soil samples were similar to the satellite ones. Among the soil attributes studied, clay presented the best correlation with R2 value of 0.75, low error and RPD value above 2.0. Other attributes related to clay also presented good correlation, such as organic matter (OM) and cation exchange capacity (CEC) with R2 values of 0.4 and 0.34 respectively.
40

Vývoj a prostorová distribuce povrchových teplot v Českých Budějovicích a okolí

KOTTOVÁ, Šárka January 2017 (has links)
The aim of this study was to detect surface temperature changes in the České Budějovice during last 30 years. The aim was also to asses the influence of vegetation on the surface temperature. The study is based on the thermal data acquired by the Landsat TM 4 and 5 and the study site was in the České Budějovice and surroundings.

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