Master of Science / Geology / Matthew W. Totten / The thermal maturity of hydrocarbon-rich source rocks can be estimated by several different methods. These methods focus on a specific geochemical or mineralogical aspect contained within the rock. Because each method has limitations, it is advisable to use several methods to better determine thermal maturation. This report summarizes two common methods used to determine thermal maturity, vitrinite reflectance and illitization. Vitrinite reflectance and illitization have both been shown to be effected by similar temperatures that are within the hydrocarbon generation window. In some previous studies these two methods give different levels of maturation when looked at in tandem. Formations such as the Woodford Shale of Oklahoma are made up almost completely of illite in the clay fraction, even at low levels of vitrinite reflectance. These are also without a clear source of potassium, which is often the limiting factor in the process of illitization. Totten et al. (2013) suggest that in place of potassium feldspars, which are a common source of K⁺ for illite (but lacking in the Woodford) that the needed K⁺ was provided by the organic material that was being altered under the same temperatures of the clay minerals. The Woodford contains large amounts of organic matter, This would be consistent with promoting illitization at lower thermal maturities than organic-poor shales.

Made available in DSpace on 2014-06-11T19:29:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-31Bitstream added on 2014-06-13T20:18:54Z : No. of bitstreams: 1 gigante_ac_me_araiq.pdf: 810984 bytes, checksum: d628a07a7c532c812f60d96301f7afff (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho propõe o desenvolvimento de um método limpo para determinação de ureia em amostras comerciais de fertilizantes utilizando a Espectroscopia de Reflectância Difusa combinada com spot test. O método desenvolvido é baseado na reação entre a ureia e o reagente cromogênico p-dimetilaminocinamaldeído (p-DAC) em meio de ácido clorídrico diluído, que resulta em um produto de coloração rósea cujo valor máximo de reflectância ocorre no comprimento de onda de 535 nm. Os parâmetros experimentais foram otimizados através dos planejamentos fatorial e composto central para a obtenção da superfície de resposta, os quais indicaram uma maior sensibilidade para o método quando se utiliza o reagente p-DAC na concentração de 0,196% (m/v) em meio de ácido clorídrico de concentração 0,0549 mol L-1, empregando etanol como solvente para as soluções. O suporte sólido para a reação é um papel de filtro qualitativo onde são colocados 20,0μL de solução de ureia seguidos de secagem com ar frio de um secador de cabelos e 20,0μL de solução de reagente p-DAC 0,196% (m/v) em meio de HCl 0,0549 mol L-1 e secagem ao ar livre, submetendo-se então o spot à leitura reflectométrica em máx. = 535 nm. Uma relação linear (R = 0,996) foi estabelecida na faixa de concentração de ureia compreendida entre 50,0 – 300 mg L-1. Os limites de detecção e de quantificação foram determinados em 5,13 mg L-1 e 17,10 mg L-1, respectivamente. O método limpo desenvolvido foi aplicado na determinação de ureia em amostras comerciais de fertilizantes onde demonstrou apresentar ótima precisão e exatidão, evidenciadas pela boa recuperação (94,2 – 107,4%), além de oferecer vantagens como simplicidade de execução e baixo consumo de reagentes, geração de mínima quantidade de resíduos, rapidez e segurança... / This work proposes the development of a clean method for determination of urea in commercial samples of fertilizers using the Diffuse Reflectance Spectroscopy combined with spot test. The method is based on the reaction between urea and the chromogenic reagent p-dimethylaminocinnamaldehyde (p-DAC) in diluted hydrochloric acid medium, which results in a pink colored product whose maximum value of reflectance occurs at a wavelength of 535 nm. The experimental parameters were optimized through a factorial and a central composite experimental design to obtain the response surface, which indicated a higher sensitivity for the method when using the reagent p-DAC in the concentration of 0.196% (w/v) in a hydrochloric acid 0.0549 mol L-1 medium, using ethanol as a solvent for the solutions. The solid support for the reaction is a qualitative filter paper where they are placed 20.0μL of urea solution followed by drying with cold air from a hair dryer and 20.0μL of reagent solution p-DAC 0.196% (w/v) in the HCl 0.0549 mol L-1 medium and drying in the air, then submitting the spot to the reflectometric reading at max = 535 nm. A linear relationship (R = 0.996) was established in the range of urea concentration between 50.0 to 300 mg L-1. The limits of detection and quantification were determined at 5.13 mg L-1 and 17.10 mg L-1, respectively. The method was applied to the clean determination of urea in commercial samples of fertilizers, which has shown to present great precision and accuracy as evidenced by the good recovery (94.2 to 107.4%) and also offers advantages such as simplicity of implementation and low consumption of reagents, generation of minimum quantity of wastes, rapidity and security, producing reliable results. As shown, the method is designed as environmentally friendly for determination of urea, as it is consistent with the Principles advocated by the Green Chemistry.

O objetivo deste trabalho foi estimar o volume de madeira de um povoamento jovem de Pinus elliottii, localizado no litoral sudeste do Rio Grande do Sul, com imagens dos sensores LISS-III/ResourceSat-1 e TM/Landsat 5, comparando o desempenho destes para tal. Obtiveram-se imagens de setembro de 2010, mês coincidente com o inventário florestal feito na área de estudo. Os valores de reflectância espectral de superfície foram recuperados das imagens originais. Após o georreferenciamento, dos pixels coincidentes com a localização das unidades amostrais do inventário florestal foram extraídos os valores das reflectâncias nas quatro bandas espectrais equivalentes aos dois sensores, cujas respostas foram comparadas. Além das bandas espectrais foram utilizados os índices de vegetação (IV’s) SR, NDVI, SAVI, MVI e GNDVI. Também, foi proposto o ajuste destes IV’s originais pela idade do povoamento, os quais foram identificados por SR_i, NDVI_i, MVI_i e GNDVI_i. A aplicação do logaritmo nas bandas espectrais melhorou os valores dos coeficientes de correlação linear (r), à exceção do IVP, retornando valores entre 0,69 (IVP) a 0,83 (Verde) para o LISS-III e entre 0,68 (Vermelho) a 0,79 (IVM) para o TM; Com os IV’s o logaritmo melhorou os valores de r somente para os IV’s originais, retornando valores de r entre 0,77 (NDVI) a 0,84 (GNDVI) com o LISS-III e entre 0,73 (NDVI) a 0,82 (MVI) para o TM. Com os IV’s ajustados pela idade do povoamento a logaritimização não se mostrou necessária para melhorar a associação linear, retornando valores de r entre 0,79 (NDVI_i) a 0,82 (MVI_i) com o LISS-III e entre 0,74 (SR_i) a 0,80 (MVI_i) com o TM. Além disso, o ajuste pela idade aumentou o intervalo dinâmico dos IV’s ajustados, e, aparentemente, aumentou a sensibilidade nos povoamentos de maior volume. Diferenças significativas na associação linear entre os dados espectrais do TM e LISS-III com o volume só foram encontradas na banda equivalente do verde. Com dados TM, a equação melhor ajustada explicou 68% da variabilidade do volume; com dados LISS-III a equação explicou 72% da variabilidade. Estas equações geraram dois mapas de volume de madeira, onde as médias das estimativas obtidas com LISS-III estiveram dentro do intervalo de confiança da média do inventário florestal em 70% dos talhões considerados; para o TM a coincidência foi de 65% dos talhões. Conclui-se que os sensores LISS-III e TM apresentam alta similaridade e que a metodologia empregada pode ser utilizada para auxiliar no inventário florestal dos povoamentos jovens de P. elliottii na área de estudo principalmente pelo fato das estimativas obtidas pelas imagens cobrirem todo o talhão, ao passo que a amostragem do inventário florestal contempla menos de 2% da área. / The aim of this work was to estimate the wood volume of a young stand of Pinus elliottii, located on the southeastern coast of the state of Rio Grande do Sul, by imagery from LISS-III/ResourceSat-1 and TM/Landsat 5 sensors, comparing their performance for such. Images were obtained on September 2010, the month coincident with the forest inventory made in the study area. The surface spectral reflectance values were retrieved from the original images. After the georeferencing, the sampling units location from the forest inventory were used to select the pixels to extract the reflectance values on the four spectral bands equivalents for the two sensors, which answers were compared. In addition to the bands were used the Vegetation Indices (VI’s) SR, NDVI, SAVI, MVI and GNDVI. Also proposed was the adjusting of these original VI’s by the stand age, which ones were identified by SR_i, NDVI_i, MVI_i and GNDVI_i. The application of logarithm in the spectral bands improved the r values, with exception to NIR, achieving values between 0.69 (NIR) and 0.83 (Green) for LISS-III and between 0.68 (Red) and 0.79 (SWIR) for TM; With the VI’s, the logarithm improved the r values only for the original VI’s, returning r values from 0.77 (NDVI) to 0.84 (GNDVI) with LISS-III and r values from 0.73 (NDVI) to 0.82 (MVI) for TM. With the VI’s adjusted by stand age the logarithm was not necessary to improve the linear association, returning r values from 0.79 (NDVI_i) to 0.82 (MVI_i) with LISS-III and r values from 0.74 (SR_i) to 0.80 (MVI_i) with TM. Moreover, adjusting by age increased the dynamic range of the VI’s adjusted, and apparently increased the sensitivity in stands with larger volume. Significant differences in the linear association between TM and LISS-III spectral data with volume were just found on the green equivalent band. With TM data, the best fitted model explained 68% of the volume variability; with LISS-III data the model explained 72% of the variability. These models generated two wood volume maps, where the average of the estimates achieved with LISS-III were within the confidence level of the average from the forest inventory on 70% of the compartments considered; for TM the coincidence was on 65% of the compartments. It is conclude that the sensors LISS-III and TM presented high similarity and the methodology applied can be used to aid in forest inventory of young stands of P. elliottii in the study area mainly because the estimates obtained by the images cover the entire compartment, while the forest inventory sampling contemplates less than 2% of the area.

abstract: Remote sensing in visible to near-infrared wavelengths is an important tool for identifying and understanding compositional differences on planetary surfaces. Electronic transitions produce broad absorption bands that are often due to the presence of iron cations in crystalline mineral structures or amorphous phases. Mars’ iron-rich and variably oxidized surface provides an ideal environment for detecting spectral variations that can be related to differences in surface dust cover or the composition of the underlying bedrock. Several imaging cameras sent to Mars include the capability to selectively filter incoming light to discriminate between surface materials. At the coarse spatial resolution provided by the wide-angle Mars Color Imager (MARCI) camera aboard the Mars Reconnaissance Orbiter (MRO), regional scale differences in reflectance at all wavelengths are dominated by the presence or absence of Fe3+-rich dust. The dust cover in many regions is highly variable, often with strong seasonal dependence although major storm events can redistribute dust in ways that significantly alter the albedo of large-scale regions outside of the normal annual cycle. Surface dust reservoirs represent an important part of the martian climate system and may play a critical role in the growth of regional dust storms to planet-wide scales. Detailed investigation of seasonal and secular changes permitted by repeated MARCI imaging coverage have allowed the surface dust coverage of the planet at large to be described and have revealed multiannual replenishing of regions historically associated with the growth of storms. From the ground, rover-based multispectral imaging acquired by the Mastcam cameras allows compositional discrimination between bedrock units and float material encountered along the Curiosity rover’s traverse across crater floor and lower Mt. Sharp units. Mastcam spectra indicate differences in primary mineralogy, the presence of iron-bearing alteration phases, and variations in iron oxidation state, which occur at specific locations along the rover’s traverse. These changes represent differences in the primary depositional environment and the action of later alteration by fluids circulating through fractures in the bedrock. Loose float rocks sample materials brought into the crater by fluvial or other processes. Mastcam observations provide important constraints on the geologic history of the Gale Crater site. / Dissertation/Thesis / Supplemental Animations for Chapter 2 / Doctoral Dissertation Geological Sciences 2018

Orientador: Matthieu Tubino / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-20T20:30:33Z (GMT). No. of bitstreams: 1 Palumbo_MarciodasNeves_M.pdf: 1659500 bytes, checksum: ddb5651da213baa8f6c6d2bc06bf367d (MD5) Previous issue date: 2011 / Resumo: A nitrofurazona e a nitrofurantoína são substâncias derivadas dos nitrofuranos e comercializadas em preparações farmacêuticas com ação bactericida, antifúngica e antimicrobiana com um amplo espectro de aplicação. Apresentam coloração amarela e comprimento de onda de máxima absorção em 370 nm. A maior parte das substâncias pertencentes ao grupo dos nitrofuranos, tem baixíssima solubilidade em água o que dificulta o desenvolvimento de métodos analíticos, sem o uso de solventes orgânicos. Neste trabalho foi desenvolvida metodologia para a determinação do teor de nitrofurazona e de nitrofurantoína em medicamentos por refletância difusa. Para a nitrofurantoína a medida é direta no fármaco, sem uso de qualquer solvente, enquanto que, para nitrofurantoína dissolve-se o fármaco em polietilenoglicol e mede-se a refletância em seguida. A técnica de refletância envolveu, para fins de comparação, a utilização de dois equipamentos distintos: (I) um espectrofotômetro Shimadzu UV-2450 com assessório de refletância e; (II) um refletômetro portátil construído em nosso laboratório. Também foram desenvolvidos duas metodologias para a análise quantitativa dos dois fármacos por transmissão em solução aquosa. Ambos os métodos na região uv-visível do espectro. Os resultados dos dois procedimentos foram comparados entre si e também com aqueles obtidos pela método oficial em high performance liquid cromatagraphy (HPLC), usando o método estatístico t pareado de Student e o teste F de Snedecor. Foi observada total concordância entre os diferentes procedimentos em nível de confiança de 95%. Entre os métodos utilizados, o de refletância difusa apresenta a maior simplicidade operacional podendo ser recomendado o seu uso para quantificação das substâncias estudadas em fármacos. Foram obtidos desvios padrão relativos (DPR) de 3,9 (I) e 5,2% (II) para a nitrofurazona e de 3,4 (I) e 8,0% (II) para nitrofurantoína, enquanto que pelo HPLC os DPR foram 4,4 e 1,8% respectivamente. O método de refletância apresenta significativa vantagem para determinação de nitrofurazona em pomadas em relação ao método oficial pela grande simplicidade operacional. Uma característica interessante do método refletométrico proposto para nitrofurazona é que, apesar de ser quantitativo, não há necessidade de pesagem de alíquota. Quanto ao método de transmitância o DPR ficou em 1,0% para nitrofurazona e 2,2% para nitrofurantoína / Abstract: Nitrofurazone and nitrofurantoin are derivatives substances from nitrofurans and are traded in pharmaceutical preparations with bactericidal , antifungal and antimicrobial actions with a broad spectrum of application. They have yellow coloration and a wavelength of maximum absorption at 370 nm. Most of the substances that belong to the group of nitrofurans have very low solubility in water which complicates the development of analytical methods, without the use of organic solvents. This research developed methodology for the determination of nitrofurazone and nitrofurantoin in drugs by diffuse reflectance. For nitrofurantoin the measure is directly on the drug, without using any solvent, whereas nitrofurantoin is dissolved in polyethylene glycol and the reflectance is measured after. The reflectance techniques involved, for comparison purposes, the use of two different equipment (I) a Shimadzu UV-2450 spectrophotometer with accessory of reflectance and (II) a portable reflectometer constructed in our laboratory. We have also developed two methodologies for quantitative analysis of the two drugs in aqueous solution by transmission. Both methods in the uv-visible region of the spectrum. The results of both procedures were compared between each other and also with those obtained by official method in high performance liquid cromatagraphy (HPLC), using the statistical method t paired of Student and the test and F of Snedecor. It was observed complete agreement between the different procedures in a accuracy level of 95%. Among the methods used, the diffuse reflectance has the highest operational simplicity and it can be recommended its use for quantification of the substances studied in drugs. It was obtained relative standard deviation (RSD) of 3.9 (I) and 5.2% (II) for nitrofurazone and 3,4 (I) and 8.0% (II) for nitrofurantoin, while at the HPLC RSD were 4.4 and 1.8% respectively. The method of reflectance has a significant advantage for the determination of nitrofurazone ointments in relation to the official method due to the great operational simplicity . An interesting feature of the refletocmetric method proposed to nitrofurazone is that, despite being quantitatively, there is no need to weigh the aliquot. As the method of transmittance the DPR was 1.0% to nitrofurazone 2.2% to nitrofurantoin / Mestrado / Quimica Analitica / Mestre em Química

Monitoring the dynamics of the productivity of ocean water and how it affects fisheries is essential for management. It requires data on proper spatial/temporal scales, which can be provided by operational ocean colour satellites. However, accurate productivity data from ocean colour imagery is only possible with proper validation of, for instance, the atmospheric correction applied to the images. In situ water reflectance data is of great value due to the requirements for validation and it is traditionally measured with the Surface Acquisition System (SAS) solar tracker system. Recently, an application, 'HydroColor', was developed for mobile devices to acquire water reflectance data. We examine the accuracy of the water reflectance acquired by HydroColor with the help of trained and untrained citizens under different environmental conditions. We used water reflectance data acquired by SAS solar tracker and HydroColor onboard the BC ferry Queen of Oak Bay from July to September 2016. Monte Carlo permutation F-tests were used to assess whether the differences between measurements collected by SAS solar tracker and HydroColor with citizens were significant. Results showed that the HydroColor measurements collected by 447 citizens were accurate in red, green, and blue bands, as well as red/green and red/blue ratios under different environmental conditions. Piecewise models were developed for correcting HydroColor blue/green water reflectance ratios based on the SAS solar tracker measurements. In addition, we found that training and environmental conditions had impacts on the data quality. A trained citizen obtained higher quality HydroColor data especially under clear skies at noon run (12:50-2:30 pm). / Graduate

The atmosphere distorts the spectrum of remotely sensed data, negatively affecting all forms of investigating Earth's surface. To gather reliable data, it is vital that atmospheric corrections are accurate. The current state of the field of atmospheric correction does not account well for the benefits and costs of different correction algorithms. Ground spectral data are required to evaluate these algorithms better. This dissertation explores using cameras as radiometers as a means of gathering ground spectral data. I introduce techniques to implement a camera systems for atmospheric correction using off the shelf parts. To aid the design of future camera systems for radiometric correction, methods for estimating the system error prior to construction, calibration and testing of the resulting camera system are explored. Simulations are used to investigate the relationship between the reflectance accuracy of the camera system and the quality of atmospheric correction. In the design phase, read noise and filter choice are found to be the strongest sources of system error. I explain the calibration methods for the camera system, showing the problems of pixel to angle calibration, and adapting the web camera for scientific work. The camera system is tested in the field to estimate its ability to recover directional reflectance from BRF data. I estimate the error in the system due to the experimental set up, then explore how the system error changes with different cameras, environmental set-ups and inversions. With these experiments, I learn about the importance of the dynamic range of the camera, and the input ranges used for the PROSAIL inversion. Evidence that the camera can perform within the specification set for ELM correction in this dissertation is evaluated. The analysis is concluded by simulating an ELM correction of a scene using various numbers of calibration targets, and levels of system error, to find the number of cameras needed for a full-scale implementation.

Biofilms are important in nature and in engineered processes. Because of this, a fundamental understanding of their growth and behaviour is required. This work aimed at monitoring biofilm growth using a biological rotating reactor and the Rotoscope biofilm monitor. Both methods worked on the principle of a rotating circular disc that was semi-submerged in water and the light reflected of the area that was outside of the water. Light reflectance on the disc was taken three times a day and the average recorded as the daily reading. It was noticed that in both systems, growth of biofilms on the discs caused a decrease in the amount of light reflected. A decrease in light reflectance indicated an increase in biofilm thickness. The growth of biofilm was confirmed by scanning electron microscopy analysis. The addition of a biocide caused a slight increase in light reflectance indicating partial biofilm removal. The Rotoscope was very sensitive to changes in biofilm characteristics. Rotoscope met the requirements needed for an on-line, real-time and non-destructive biofilm monitoring system. The aged anolyte was effective in killing both suspended and biofilm bacteria at a concentration of 1:10 irrespective of its age and storage conditions. Exposure of aerobic bacteria to different concentrations of sodium nitrite at different time intervals indicated that sodium nitrite had a limited, or no biocidal effect on these bacteria mostly encountered in biofilms. The ready to use chlorine dioxide was also used as the means of controlling biofilms. MIC for RTU ClO2 was found to be 80ppm, which in certain instances killed all bacteria immediately upon exposure while in other cases an exposure time of 1h was required. It was indicated that at this concentration, biofilms were removed. This was confirmed by scanning electron microscopy analysis. Proteins of suspended bacteria treated with 1:10 and 1:100 anolyte dilutions and the control were extracted and compared using SDS-PAGE. Protein bands of bacteria treated with 1:10 NaCl derived anolyte were fewer and fainter as compared to those from untreated cells. More bands were produced in cells treated with 1:100 NaCl derived anolyte as compared to the untreated cells. Cells treated with the non-halide anolyte, both 1:10 and 1:100 dilutions, produced more bands than in the untreated cells. Anolyte destroyed vital proteins for bacterial survival causing cell death or it caused fragmentation of proteins to small peptides, reducing the number of viable cells. NaNO2 was ineffective as biocide while aged anolyte and RTU liquid ClO2 were effective as biocides. SDS-PAGE indicated that anolyte killed bacteria by affecting their proteins. / Dissertation (MSc)--University of Pretoria, 2008. / Microbiology and Plant Pathology / unrestricted

Orientador: Carlos Roberto de Souza Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-24T06:26:10Z (GMT). No. of bitstreams: 1 AmorerHernandez_Emanuel_M.pdf: 9074844 bytes, checksum: 181c64a39a24efc51dea2add5a69d676 (MD5) Previous issue date: 2013 / Resumo: A pesquisa compreende estudos sobre a assinatura ultraespectral e multiespectral de fosfatos de origem ígnea e sedimentar contidos, respectivamente, nos depósitos de Catalão I (GO), Tapira (MG) e Rocinha-Lagamar (MG), centro-oeste do Brasil. Medidas de reflectância e emissividade (focadas na faixa de 8-12µm) foram analisadas em conjunto com dados de Difração de Raios X e Fluorescência de Raios X visando a determinação da mineralogia e quimismo das rochas envolvidas nas áreas de estudo. Os fosfatos ígneos de Catalão I e Tapira, inseridos na Província Ígnea do Alto Paranaíba, encontram-se hospedados em complexos carbonatíticos. Apresentam Elementos de Terras Raras em sua composição e feições de absorção intrínsecas em espectros de reflectância em torno de 0,75µm. A profundidade e forma das feições auxiliam na identificação e qualificação de monazita, fluoroapatita e cloroapatita como minerais de minério. Associações comuns nas zonas mineralizadas e que apresentam assinaturas espectrais características incluem fluoroapatite-ajoita-vermiculita; fluoroapatita-vermiculita-calcita e fluoroapatita-calcita-monazita. Teores anômalos de fosfato ocorrem na presença de vermiculita, flogopita, calcita, dolomita, caulinita e ajoita-corvusita, todos passíveis de identificação através de espectros de reflectância. Os fosfatos metassedimentares de Rocinha e Lagamar, inseridos na Faixa de Dobramentos Brasília, encontram-se hospedados em fosfoarenitos de origem controversa no Grupo Bambuí. Correspondem a fluorapatitas, onde o intemperismo, além de mudanças próprias da apatita durante o ciclo do P sedimentar, removeram seu conteúdo de ETR. As argilas presentes nesses depósitos podem ser utilizadas como indicadores indiretos da presença de teores anômalos de fosfatos. As assembléias minerais observadas incluem illita-fluoroapatita-quartzo; fluoroapatita-caulinita-quartzo; fluoroapatita-illita-muscovita. Clorita e calcita são minerais subordinados. As análises espectro-mineralógicas, difratométricas e geoquímicas de rochas desses depósitos permitiram a constituição de bibliotecas espectrais que foram utilizadas para subsidiar a classificação espectral de dados do sensor ASTER adquiridos sobre as áreas de estudo. As técnicas Spectral Angle Mapper (SAM) e Mixture Tuned Matched Filtering (MTMF) foram testadas. No complexo de Catalão I foi possível separar, nas imagens, zonas ricas em monazita, vermiculita, foscorito magnetítico e solos isalteríticos com baixo teor de fosfatos. No complexo de Tapira e região de Araxá, foi possível distinguir ajoita-corvusita, isalteritos com fosfatos secundários, vermiculita e carbonatitos picríticos. Nas minas de Rocinha e Lagamar, foi possível discriminar as rochas encaixantes das rochas hospedeiras nas imagens em base a feições das argilas. Em Rocinha, fosfoarenitos apatiticos com ilita, fosfoarenitos calcareos con ilita e muscovita, arenitos calcáreos e solos transportados foram discriminados. Estes resultados reforçam a potencialidade de qualificar e quantificar fosfatos a partir de sensores hiperespectrais orbitais (Hyperion, HyMap) e aerotransportados (ProspecTIR) atualmente em operação e outros sensores próximos a serem colocados em funcionamento (EnMap, PRISMA, HISUI, HyspIRI), com desdobramentos importantes para programas de exploração mineral / Abstract: In order to aid phosphate exploration programs, this research defined the reflectance and emission spectroscopy of cretacic carbonatites related to igneous phosphates and neoproterozoic phosphoritic rocks from the Catalão I (GO), Tapira, Rocinha and Lagamar (MG) mine sites, Midwestern Brazil. The main goal of this study was to identify mineral and lithotype endmembers that can be tracked and detected through multispectral remote sensing using ASTER images. Reflectance, Diffuse reflectance and emission measurements were analyzed with X Ray Fluorescence and X Ray Diffraction data to diminish uncertainties and have a full knowledge of the chemistry and mineralogy of the studied locations. For the igneous carbonatitic phosphates of Catalão I and Tapira complexes, inserted in the Alto Paranaíba Igneous Province (PIAP) it was determined that the REEs inclusions present in phosphates can be detected through reflectance spectroscopy, leading to mineral species recognition by analyzing of the 0.75µm absorption feature. In this region of the spectra, in the context of carbonatitic intrusions and REEs concentration, monazite, fluorapatite and apatite-(Cl) can be distinguished with Hyperspectral reflectance spectrometers from raw samples. Main mineral assemblages were fluorapatite-ajoite-vermiculite; fluorapatite-vermiculite-calcite and fluorapatite-calcite-monazite. It was also possible to recognize vermiculite, phlogopite, calcite, dolomite, kaolinite and ajoite-corvusite as secondary absorption features related to high phosphatic concentration. For the metasedimentary phosphates of Rocinha and Lagamar that correspond to sedimentary apatites-(F), those REEs absorption features that discriminated igneous phosphates are not present, probably due to weathering of apatite and natural changes on the crystal structure that happen during the P cycle. However, for the Rocinha and Lagamar mine sites, it was observed that clays were secondary markers that indicated high or mild phosphate yield. Mineral assemblages observed for the sedimentary phosphates were illite-fluorapatite-quartz; fluorapatite-kaolinite-quartz; fluorapatite-illite-muscovite. Chlorite and calcite are secondary absorption features. With these results, spectral libraries were mounted and tested in ASTER images from the Catalão I and Tapira Carbonatitic Complexes and from the Rocinha and Lagamar mines. Spectral Angle Mapper (SAM) and Mixture Tuned Matched Filtering (MTMF) were performed on the images, being able to distinguish pixels with high favourability of monazite, vermiculite, magnetitic phoscorite and isalteritic soils of poor phosphate content for Catalão I. Ajoite-Corvusite, Secondary phosphates, vermiculite and Picritic Carbonatite was discriminated for the Tapira and Araxá region, indicating previously unmapped occurrences. Using MTMF in the Tapira image, it was possible to refine the SAM results, allowing better accuracy with the same endmembers, giving low infeasibility results with high Matched Filtering results for 75% of the endmembers. In the Rocinha and Lagamar mines, it was able to discriminate wall rock from mine-objective rock using the Lagamar mine endmembers. The Rocinha mine endmembers were of adequate use for the Rocinha mine, but failed to distinguish mined rock from wall rock in the Lagamar mine, probably given their higher kaolinite content. These results encourage further exploration of the data with current (Hyperion, ProspecTIR, HyMap) and future (EnMap, PRISMA, HISUI, HyspIRI) hyperspectral data in order to fully quantify phosphate favourability in phosphate exploration programs / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

<p>To correctly reproduce the appearance of different objects in computer graphics applications, numerous lighting models have been proposed over the past several decades. These models are among the most important components in the modern graphics pipeline since they decide the final pixel color shown in the generated images. More physically valid parameters and functions have been introduced into recent models. These parameters expanded the range of materials that can be represented and made virtual scenes more realistic, but they also made the lighting models more complex and dependent on measured data.</p> <p>Artificial neural networks, or neural networks are famous for their ability to deal with complex data and to approximate arbitrary functions. They have been adopted by many data-driven approaches for computer graphics and proven to be effective. Furthermore, neural networks have also been used by the artists for creative works and proven to have the ability of supporting creation of visual effects, animation and computational arts. Therefore, it is reasonable to consider artificial neural networks as potential tools for representing lighting models. Since shaders are used for general-purpose computing, neural networks can be further combined with modern graphics pipeline using shader implementation. </p> <p>In this research, the possibilities of shader-based neural networks to be used as an alternative to traditional lighting models are explored. Fully connected neural networks are implemented in fragment shader to reproduce lighting results in the graphics pipeline, and trained in compute shaders. Implemented networks are proved to be able to approximate mathematical lighting models. In this thesis, experiments are described to prove the ability of shader-based neural networks, to explore the proper network architecture and settings for different lighting models. Further explorations of possibilities of manually editing parameters are also described. Mean-square errors and runtime are taken as measurements of success to evaluate the experiments. Rendered images are also reported for visual comparison and evaluation.</p>