As indústrias de fertilizantes fosfatados no Brasil são responsáveis pela produção anual de 5,5x106 toneladas de um subproduto denominado fosfogesso (PG), que pode ser considerado como TENORM (Technologically Enhanced Naturally Occurring Radioactive Material) e vem sendo estocado em pilhas à céu aberto ao lado das instalações produtoras. Com a presença de radionuclídeos no fosfogesso, faz-se necessário certa restrição para seu uso na agricultura. A Agência Regulatória Brasileira - CNEN estabeleceu limites de 1 Bq g-1 para 226Ra e 228Ra para o uso de fosfogesso na agricultura. No Brasil, esse resíduo vem sendo utilizado como condicionador de solo. Para a utilização segura do PG na agricultura é importante estimar qual poder de lixiviação dos radionuclídeos presente no mesmo. O objetivo do presente trabalho é avaliar a disponibilidade do 210Po na utilização do PG na agricultura como condicionador de solo. Para isso, foi realizado experimento com colunas em PVC preenchidas com amostras de solo argiloso, solo arenoso e PG. As colunas foram lixiviadas com água deionizada. A técnica usada para a determinação de 210Po nas amostras de solo, solo + PG e PG foi a espectrometria alfa que se adéqua para a medição da concentração de 210Po em amostras ambientais, além de apresentar alta eficiência e alta sensibilidade. Para que se pudesse avaliar a disponibilidade de 210Po, a concentração obtida no lixiviado foi comparada com a concentração total de 210Po nas amostras de solo, solo + fosfogesso e fosfogesso. Os resultados obtidos para concentração de atividade de 210Po nas amostras de solo argiloso foram aproximadamente 2,5 vezes maiores do que as amostras de solo arenoso. Para as amostras de fosfogesso os resultados para concentração de atividade de 210Po variaram de 155±11 a 346±7 Bq Kg-1. Conclui-se que mesmo com a adição do fosfogesso no solo, as amostras não apresentaram um aumento na concentração final do radionuclídeo estudado. Pode-se concluir que os radionuclídeos presentes no fosfogesso não estão disponíveis no lixiviado. / The main phosphate industries in Brazil are responsible for the production of 5.5x106 metric tons of a TENORM residue (phosphogypsum-PG) annually, which is stored in stacks. The presence of radionuclides puts restrictions on the use of phosphogypsum in building materials and in soil amendments. The Brazilian regulatory body (CNEN) ruled that phosphogypsum would only be permitted for use in agriculture or in the cement industry if the concentration of 226Ra and 228Ra does not exceed 1 Bq g-1. In Brazil, phosphogypsum has been widely used as soil amendment, to improve the soil fertility. To assure a safe utilization in agriculture, it is important to estimate the lixiviation of the radionuclides in phosphogypsum. The main objective of this study is to evaluate the availability of 210Po in the utilization of phosphogypsum in agriculture as soil amendment. For this purpose, an experiment was carried out, in which columns filled with sandy and clay Brazilian typical soils and phosphogypsum were percolated with water, to achieve a mild extraction of 210Po. The technique used for the determination of 210Po in the samples of soil, soil + phosphogypsum and phosphogypsum was alpha spectrometry which is suitable for the measurement of low activity of 210Po in environmental samples, since it presents high efficiency and sensibility. The concentration present in the leachate was compared with the total concentration of 210Po in soil, in the mixture soil + phosphogypsum and phosphogypsum, in order to evaluate the availability of 210Po. The results obtained for the activity concentrations of 210Po in the clay soil were approximately 2.5 times higher than the sand soil. The results obtained for the radionuclides concentration in the phosphogypsum varied from 155±11 to 346±7 Bq kg-1 for 210Po. However, the addition of phosphogypsum to the soils studied did not represent any increase in the final activity concentration. The results obtained for the activity concentration of 210Po in the leachate were close to the detection limits of the methodologies adopted, giving evidence that, although the radionuclides are present in the PG, they are not available in the leachate.

As indústrias de fertilizantes fosfatados no Brasil são responsáveis pela produção anual de 5,5x106 toneladas de um subproduto denominado fosfogesso (PG), que pode ser considerado como TENORM (Technologically Enhanced Naturally Occurring Radioactive Material) e vem sendo estocado em pilhas à céu aberto ao lado das instalações produtoras. Com a presença de radionuclídeos no fosfogesso, faz-se necessário certa restrição para seu uso na agricultura. A Agência Regulatória Brasileira - CNEN estabeleceu limites de 1 Bq g-1 para 226Ra e 228Ra para o uso de fosfogesso na agricultura. No Brasil, esse resíduo vem sendo utilizado como condicionador de solo. Para a utilização segura do PG na agricultura é importante estimar qual poder de lixiviação dos radionuclídeos presente no mesmo. O objetivo do presente trabalho é avaliar a disponibilidade do 210Po na utilização do PG na agricultura como condicionador de solo. Para isso, foi realizado experimento com colunas em PVC preenchidas com amostras de solo argiloso, solo arenoso e PG. As colunas foram lixiviadas com água deionizada. A técnica usada para a determinação de 210Po nas amostras de solo, solo + PG e PG foi a espectrometria alfa que se adéqua para a medição da concentração de 210Po em amostras ambientais, além de apresentar alta eficiência e alta sensibilidade. Para que se pudesse avaliar a disponibilidade de 210Po, a concentração obtida no lixiviado foi comparada com a concentração total de 210Po nas amostras de solo, solo + fosfogesso e fosfogesso. Os resultados obtidos para concentração de atividade de 210Po nas amostras de solo argiloso foram aproximadamente 2,5 vezes maiores do que as amostras de solo arenoso. Para as amostras de fosfogesso os resultados para concentração de atividade de 210Po variaram de 155±11 a 346±7 Bq Kg-1. Conclui-se que mesmo com a adição do fosfogesso no solo, as amostras não apresentaram um aumento na concentração final do radionuclídeo estudado. Pode-se concluir que os radionuclídeos presentes no fosfogesso não estão disponíveis no lixiviado. / The main phosphate industries in Brazil are responsible for the production of 5.5x106 metric tons of a TENORM residue (phosphogypsum-PG) annually, which is stored in stacks. The presence of radionuclides puts restrictions on the use of phosphogypsum in building materials and in soil amendments. The Brazilian regulatory body (CNEN) ruled that phosphogypsum would only be permitted for use in agriculture or in the cement industry if the concentration of 226Ra and 228Ra does not exceed 1 Bq g-1. In Brazil, phosphogypsum has been widely used as soil amendment, to improve the soil fertility. To assure a safe utilization in agriculture, it is important to estimate the lixiviation of the radionuclides in phosphogypsum. The main objective of this study is to evaluate the availability of 210Po in the utilization of phosphogypsum in agriculture as soil amendment. For this purpose, an experiment was carried out, in which columns filled with sandy and clay Brazilian typical soils and phosphogypsum were percolated with water, to achieve a mild extraction of 210Po. The technique used for the determination of 210Po in the samples of soil, soil + phosphogypsum and phosphogypsum was alpha spectrometry which is suitable for the measurement of low activity of 210Po in environmental samples, since it presents high efficiency and sensibility. The concentration present in the leachate was compared with the total concentration of 210Po in soil, in the mixture soil + phosphogypsum and phosphogypsum, in order to evaluate the availability of 210Po. The results obtained for the activity concentrations of 210Po in the clay soil were approximately 2.5 times higher than the sand soil. The results obtained for the radionuclides concentration in the phosphogypsum varied from 155±11 to 346±7 Bq kg-1 for 210Po. However, the addition of phosphogypsum to the soils studied did not represent any increase in the final activity concentration. The results obtained for the activity concentration of 210Po in the leachate were close to the detection limits of the methodologies adopted, giving evidence that, although the radionuclides are present in the PG, they are not available in the leachate.

Quantum cascade laser (QCL) diodes have potential applications in many areas including emissions analysis and explosives detection, but like many solid-state devices they suer from degraded performance at higher temperatures. To alleviate this drawback, the thermal properties of the QCL diodes must be better understood. Using molecular dynamics (MD) and photothermal radiometry (PTR), the thermal conductivity of a representative QCL diode is computed and measured respectively. The MD results demonstrate that size eects are present in the simulated systems, but if these are accounted for by normalization to experimental results the thermal conductivity of the QCL can be reasonably obtained. The cross-plane conductivity is found to be in the range of 1.8 to 4.3 W=m K, while the in-plane results are in the range of 3.7 to 4.0 W=m K. These values compare well with experimental results from the literature for both QCL materials and for AlInAs and GaInAs, which the QCL is composed of. The cross-plane conductivity results are lower than those of either AlInAs or GaInAs, which demonstrates the phonon scattering at the interfaces. The in-plane results are between AlInAs and GaInAs, which is to be expected. The PTR results are less concrete, as there seem to be heat transfer eects active in the samples which are not included in the models used to t the frequency scans. These effects are not 2D heat transfer artifacts nor are they the result of volumetric absorption. It is possible that they are the results of plasmon induction, but this is only supposition. As the data stand, the PTR and MD results are within an order of magnitude of each other and follow reasonable trends, which suggests that both results are not too far o from reality. While the experimental results are not entirely conclusive, the simulations and experiments corroborate each other suciently to warrant further investigation using these techniques. Additionally, the simulations present sucient internal consistency so as to be useful for thermal property investigation independent of the PTR results.

Dental secondary caries is the carious lesion developed around existing restoration margins. Many new technologies have been developed for caries detection purposes, but their performance is unsatisfactory for the specific purpose of secondary caries diagnosis. Therefore, the development of a novel technology to detect secondary caries has been highly necessary. The objective of this research was to investigate the ability of photothermal radiometry and modulated luminescence to detect secondary caries: wall lesions and outer lesions. Changes in experimental PTR-LUM signals due to sequential demineralization on vertical walls of sectioned tooth samples were investigated. Another study was conducted to investigate how two different types of secondary caries, wall lesions and outer lesions, affect the PTR-LUM signals. The studies demonstrated that PTR-LUM is sensitive to progressive demineralization and remineralization on vertical walls of sectioned tooth samples, as well as to the presence of wall lesions and outer lesions developed around composite restorations.

Dental secondary caries is the carious lesion developed around existing restoration margins. Many new technologies have been developed for caries detection purposes, but their performance is unsatisfactory for the specific purpose of secondary caries diagnosis. Therefore, the development of a novel technology to detect secondary caries has been highly necessary. The objective of this research was to investigate the ability of photothermal radiometry and modulated luminescence to detect secondary caries: wall lesions and outer lesions. Changes in experimental PTR-LUM signals due to sequential demineralization on vertical walls of sectioned tooth samples were investigated. Another study was conducted to investigate how two different types of secondary caries, wall lesions and outer lesions, affect the PTR-LUM signals. The studies demonstrated that PTR-LUM is sensitive to progressive demineralization and remineralization on vertical walls of sectioned tooth samples, as well as to the presence of wall lesions and outer lesions developed around composite restorations.

Diss. (sammanfattning) Linköping : Univ., 2001. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Wisconsin-Madison, 1989. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves: 108-122).

Orientador: Alexandre Dal Pai / Resumo: O presente trabalho sugere modelos de correção para a irradiância solar difusa medida com o disco de sombreamento. A irradiância global foi medida por um piranômetro Eppley-PSP; a irradiância normal direta por um pireliômetro Eppley-NIP adaptado a um dispositivo de rastreamento solar ST-3 e irradiância difusa por um piranômetro Eppley-PSP instalado em um disco de sombreamento. O Laboratório de Radiometria Solar da Universidade Estadual Paulista forneceu as medições durante os anos de 1997 a 2000. Os resultados mostraram que ambos os modelos sugeridos, o modelo para todas as coberturas de céu e o modelo para as diferentes coberturas de céu melhoram a medida da irradiância difusa pelo método do disco de sombreamento permitindo a geração de um banco de dados de radiação global, direta e difusa, sem altos investimentos financeiros. A medida da Irradiância difusa sem correção apresentou um MBE de -4,64% e um RMSE de 12,23%, enquanto que os modelos de correção para todas as coberturas de céu e para as diferentes coberturas de céu obtiveram MBE de 0,48% e 0,85 e RMSE de 10,52% e 9,91%, respectivamente. / Doutor

The Global L-band Observatory for Water Cycle Studies (GLOWS) is designed as a follow-on to the Soil Moisture Active Passive (SMAP) observatory launched in 2015. While GLOWS is essentially copying many aspects of the SMAP mission, a key change has been made in the antenna technology. SMAP uses a reflector antenna and to reduce mission costs GLOWS uses a metamaterial lens antenna. This type of antenna is less efficient, so it must be proven that GLOWS can achieve the same uncertainty levels in soil moisture measurements as SMAP. In this work, a unified framework for modeling and analyzing GLOWS' ability to meet all mission and measurement requirements is developed. A model for the uncertainty effects of the lens antenna is developed and used to show that so long as the lens efficiency is above a threshold determined by the accuracy of the lens physical temperature knowledge, GLOWS will also be able to achieve all measurement requirements. It is shown that GLOWS is able to copy the design parameters of SMAP and achieve the same mission requirements.

Accurate temperature and thermal property measurements are critical for the modeling and prediction of heat transfer. In many industries thermal management is a limiting factor of performance, and rely on advanced modeling techniques to develop and design methods to better manage thermal energy. This study expands the thermal property and pyrometry measurement capabilities by developing three new techniques based on thermal emission’s nonlinear dependence on temperature.