O carvão responde pela maior parte da produção da eletricidade em vários países, e é o combustível mais queimado em caldeiras de usinas termelétricas no mundo, sendo assim uma das principais fontes de gases de efeito estufa. A biomassa de madeira é um combustível renovável, e o dióxido de carbono tem um ciclo curto nos processos de oxidação das biomassas. Este estudo teve como principais objetivos comparar a combustão de dois carvões minerais (um brasileiro e outro colombiano) e um carvão vegetal em um forno tubular de queda livre, comumente chamado de forno DTF (Drop Tube Furnace). Um DTF consiste em um reator cilíndrico vertical, com aquecimento homogêneo, onde a combustão de partículas de um combustível sólido ocorre em condições semelhantes às que ocorrem em caldeiras de leito pulverizado. Recentemente foi construído no Laboratório de Combustão do Departamento de Engenharia Mecânica da UFRGS um forno DTF com 1,340 m de altura útil e que opera até 1200°C. A combustão foi avaliada a 1100°C em termos de burnout, análise de temperatura e espécies químicas ao longo do comprimento do reator. Dos resultados obtidos, o carvão colombiano mostrou-se mais reativo por ter sido consumido mais rapidamente, alcançando burnouts mais elevados do que o carvão brasileiro e o carvão vegetal. O carvão vegetal e o carvão brasileiro obtiveram burnouts semelhantes ao longo do comprimento do forno. O carvão vegetal liberou mais CO que os carvões minerais no início da combustão. A emissão de NO foi mais alta na combustão do carvão colombiano e do carvão vegetal porque estes concentram mais nitrogênio em sua estrutura. As emissões de SO2 também foram proporcionais ao teor de enxofre nos carvões, de maneira que o carvão brasileiro apresentou as maiores concentrações, seguido pelo carvão colombiano e por último, o carvão vegetal. O ar comprimido afeta de forma regular a temperatura no forno, sendo maior a diferença de temperatura entre o perfil com ar comprimido e o perfil sem ar comprimido próximo ao ponto de injeção, o queimador. O perfil sem ar comprimido demostra que o aquecimento do DTF não é homogêneo. A combustão do carvão aumenta significativamente a temperatura no forno, chegando próximo ao perfil de temperatura sem a injeção de ar comprimido. Este trabalho incluiu ainda um estudo prévio do dosador de partículas, considerando diferentes tipos de carvão e carvão vegetal. / Coal is the main fuel in thermoelectric generation in many countries in the world, in spite of its well known being one of the main sources of greenhouse gases. On the other hand, wood biomass is a renewable energy source, associated to a short life cycle of the carbon dioxide produced in its oxidation processes. This study aimed at comparing the reactivity, in combustion atmosphere, of two coals, a Colombian one and a Brazilian one, as well as of a charcoal, by means of a drop tube furnace (DTF). A DTF consists in a vertical cylindrical reactor, capable of mantaining a homogeneously heated section along which combustion of solid fuel particles take place in similar heating rate and temperature conditions as those that are found in the operation of industrial-scale pulverized coal boilers. A DTF was built in the Combustion Laboratory of the Mechanical Engineering Department at Federal University of Rio Grande do Sul. The reactor measures 1340 mm in testing height and can be heated to provide inner temperatures up to 1200ºC. Combustion of samples of the selected fuels was evaluated in terms of the evolution of burnout, gas temperature and composition of the gas and of the char collected in a set of positions along the DTF axys. As main results, it was observed that the reactivity of the Colombian coal is higher than that of the other fuels all along the DTF height. Similar results for burnout were found for the Brazilian coal and the charcoal. Emissions were also investigated. It was observed that combustion of the charcoal releases more CO in the initial portion of the particles displacement inside the reactor. Emission of NO was found to be higher in the combustion of the Colombian coal as well as in the combustion of the charcoal, accomopanying the higher nitrogen content in the composition of the two fuels. Emissions of SO2 were also proportional to sulphur content in the fuels, so that the higher amounts of this species were found in the combustion of the Brazilian coal, followed by the Colombian coal and the charcoal. Temperature measurements were made with a probe specifically designed for that purpose. It was verified that the DTF provides a satisfactory testing length as long as combustion takes place. Discussion of the results includes the calibration of the dosing apparatus.

O trabalho consiste em uma análise experimental comparativa do processo de combustão e de transferência de calor ao longo de uma fornalha flamotubular. Os combustíveis utilizados são o óleo diesel e o biodiesel proveniente de óleo de fritura. Uma outra parcela deste trabalho é investigar os níveis de emissões gasosas no processo de combustão do biodiesel em fornalha flamotubular. Não seria possível realizar esta pesquisa sem uma fornalha flamotubular dotada de câmaras calorimétricas, janelas de observação e extração de gás, e totalmente instrumentada. Assim, foi efetuado em paralelo o projeto e a construção de uma fornalha calorimétrica flamotubular. Os parâmetros utilizados para se analisar os combustíveis na fornalha são: rendimento térmico, taxa de fluxo mássico, temperatura de chama e perda de carga. Observou-se que o óleo diesel apresentou maior taxa de transferência de calor para a maioria das seções expostas à chama. Na região onde o corpo da chama não está presente, a taxa de transferência de calor do biodiesel torna-se ligeiramente superior. Em relação às emissões gasosas observaram-se baixos níveis de poluentes / This work consists in a comparative experimental evaluation of the process of combustion and heat transfer along a flame tube furnace. The fuels used are diesel oil and ethyl ester from waste vegetable oil (biodiesel). Another part of this work investigates the percentage of pollutants and emissions of gases in the flame tube furnace. It would not be possible to carry out this research without a flame tube furnace endowed with calorimetric chambers, windows of observation and extraction of gases, and totally instrumented. Thus, the project and the construction of a flame tube calorimetric furnace were done parallel. The parameters used to analyze the fuels in the furnace are: thermal efficiency, mass flow rate, temperature of flame and draught loss. It was observed that diesel oil presented higher heat transfer rate in most parts of the furnace that was near the flame. In the region where the body of flame is not present, the heat transfer rate of biodiesel becomes a little higher. In relation to emission of gases, it was observed low indexes of pollutants

O presente trabalho envolve um estudo teórico e experimental do escoamento bifásico externo a banco de tubos. Inicialmente, apresenta-se uma ampla revisão da literatura sobre padrões de escoamento, fração de vazio e perda de pressão, durante escoamentos monofásicos e bifásicos externos a banco de tubos. Nesta análise são também descritos os métodos de previsão destes parâmetros. Verificam-se diferenças significativas entre as estimativas proporcionadas por eles, fato que indica a inexistência de métodos generalizados. Posteriormente é apresentada uma descrição detalhada da bancada experimental projetada e construída durante o doutoramento. O aparato completo compõe-se da seção de testes, circuito de água, sistema de compressão e condicionamento de ar, e seções de injeção dos fluxos e condicionamento do escoamento. A seção de testes consiste em um banco de tubos distribuídos segundo configuração triangular normal, com os tubos apresentando diâmetro externo de 19,1 mm, comprimento de 381 mm, e espaçamento transversal de 24 mm. Os experimentos foram realizados para escoamento vertical ascendente de misturas água-ar e velocidades superficiais da fase líquida e gás de 0,020 a 1,500 m/s e de 0,10 a 10,00 m/s, respectivamente. Neste estudo foram desenvolvidas técnicas inéditas para determinação experimental da fração de vazio superficial no interior do banco de tubos baseadas em sistemas óptico e de sensoriamento capacitivo. Os padrões de escoamento foram identificados subjetivamente através de visualização de imagens e vídeos do escoamento, e objetivamente com o auxílio do método de agrupamento de dados k-means utilizando parâmetros baseados no sinal de perda de pressão e do sensoriamento capacitivo. Identificou-se subjetivamente os padrões de escoamento bolhas, bolhas dispersas, bolhas grandes, agitante, intermitente e anular. Constatou-se equivalência entre os padrões de escoamento identificados através dos métodos objetivo e subjetivo. Resultados experimentais para fração de vazio foram obtidos através de técnicas óptica e capacitiva. Constatou-se que o traçador rodamina B utilizado no método óptico altera as condições do escoamento, ainda que em concentrações reduzidas. A partir dos resultados obtidos com o sensoriamento capacitivo estimou-se a fração de vazio para o padrão bolhas. Resultados para a parcela friccional da perda de pressão também foram levantados. Constata-se o incremento da fração de vazio e da parcela friccional da perda de pressão com as velocidades superficiais das fases líquida e gás. Os resultados para fração de vazio foram comparados com métodos de previsão da literatura, e de maneira geral os métodos preveem as tendências dos resultados experimentais apenas para vazões de líquido reduzidas. Analogamente, os resultados para perda de pressão foram comparados com estimativas segundo métodos da literatura, concluindo que os métodos não preveem satisfatoriamente os resultados obtidos. Desta forma, foram propostos novos métodos de previsão para padrões de escoamento, fração de vazio e parcela friccional da perda de pressão, desenvolvidos a partir de análises dos mecanismos dominantes do escoamento, e adotando parâmetros adimensionais para correlacionar os dados. Os métodos propostos preveem satisfatoriamente os resultados experimentais deste estudo e da literatura para escoamentos bifásicos água-ar. / The present thesis concerns a theoretical and experimental study of external two-phase flows across tube bundles. Initially, a comprehensive literature review covering flow patterns, void fraction and pressure drop for single and two-phase flows across tubes bundle is presented. The review also describes predictive methods for these parameters. A comparison of these methods reveals reasonable disagreement among their predictions, indicating the absence of generalized methods. Subsequently, the apparatus and instrumentation designed and built to obtain the experimental data are described. The experimental apparatus comprises the test section, a water loop, air compression and conditioning systems, and sets for fluid flow injections and conditioning. The test section is a normal triangular tube bundle, with 19.1 mm OD tubes, 381 mm long and transversal pitch of 24 mm. The experiments were performed for air-water upward vertical flow, for superficial liquid and gas velocities ranging from 0.020 to 1.500 m/s and 0.10 to 10.00 m/s, respectively. Innovative techniques to evaluate the void fraction within the bundle were developed based on capacitive and optical methods. The flow patterns were identified subjectively and objectively by k-means clustering method, using as clustering parameters the pressure drop and the capacitive signals. Bubbles, dispersed bubbles, large bubbles, churn, intermittent and annular flow patterns were identified subjectively. The data groups identified by the objective method are representative of the flow patterns. Void fraction measurements were obtained for bubbly flow using both techniques (optical and capacitive). The void fraction data based on the optical method had its experimental range limited due to changes in the flow characteristics caused by the addition of the fluorescent dye Rhodamine B. The experimental results indicate that the void fraction increases with increasing the superficial velocities of both phases. In general, the void fraction predictive methods available in the literature capture the trends of the experimental results only for reduced liquid flow rates. According to the experimental results, the frictional pressure drop increases asymptotically with increasing the flow rates of both phases. None of the predictive methods from literature evaluated in the present study predicted satisfactorily the experimental results. Methods for prediction of flow patterns, void fraction and frictional pressure drop parcel were also developed in the present study. These methods provided reasonable predictions of the experimental results obtained in the present study, and also from the literature for air and water flows across tube bundles.

abstract: This dissertation examines the efforts of the Carnegie Image Tube Committee (CITC), a group created by Vannevar Bush and composed of astronomers and physicists, who sought to develop a photoelectric imaging device, generally called an image tube, to aid astronomical observations. The Carnegie Institution of Washington’s Department of Terrestrial Magnetism coordinated the CITC, but the committee included members from observatories and laboratories across the United States. The CITC, which operated from 1954 to 1976, sought to replace direct photography as the primary means of astronomical imaging. Physicists, who gained training in electronics during World War II, led the early push for the development of image tubes in astronomy. Vannevar Bush’s concern for scientific prestige led him to form a committee to investigate image tube technology, and postwar federal funding for the sciences helped the CITC sustain development efforts for a decade. During those development years, the CITC acted as a mediator between the astronomical community and the image tube producers but failed to engage astronomers concerning various development paths, resulting in a user group without real buy-in on the final product. After a decade of development efforts, the CITC designed an image tube, which Radio Corporation of American manufactured, and, with additional funding from the National Science Foundation, the committee distributed to observatories around the world. While excited about the potential of electronic imaging, few astronomers used the Carnegie-developed device regularly. Although the CITC’s efforts did not result in an overwhelming adoption of image tubes by the astronomical community, examining the design, funding, production, and marketing of the Carnegie image tube shows the many and varied processes through which astronomers have acquired new tools. Astronomers’ use of the Carnegie image tube to acquire useful scientific data illustrates factors that contribute to astronomers’ adoption or non-adoption of those new tools. / Dissertation/Thesis / Doctoral Dissertation History and Philosophy of Science 2019

Angiogenesis is a crucial process under both physiological and pathological conditions. Vascular endothelial growth factor (VEGF) A and its cognate receptor, vascular endothelial growth factor receptor 2 (VEGFR2) are key regulators of angiogenesis. Plasma membrane (PM) levels of VEGFR2 are regulated by de novo synthesis, and by both exocytic and endocytic trafficking. VEGF-binding to VEGFR2 induces phosphorylation of key tyrosine residues located in the cytosolic domain of the receptor, followed by clathrin-mediated endocytosis and signal transduction leading to vascular morphogenesis. Disabled protein 2 (Dab2) is a cytosolic, clathrin-adaptor protein that is known to regulate endocytosis of certain cell surface receptors. Studies of Dab2 function have revealed its role in the development of embryonic vasculature. However, the mechanism of Dab2 function, particularly in conjunction with endosomal VEGFR2, remains poorly understood. Our results show that Dab2 interacts with VEGFR2 and that upon VEGF stimulation the two proteins co-localize within Rab5-positive early endosomes. Knockdown of Dab2 reduces levels of VEGF-induced phosphorylation of VEGFR2 at residue Y1175. This is significant because phosphorylation of VEGFR2-Y1175 is crucial for pro-angiogenic signal transduction. Moreover, knockdown of Dab2 causes an increased trafficking of VEGFR2 to late endosomes (LE). Finally, this altered VEGFR2 trafficking following Dab2 knockdown has major functional consequences for endothelial cells, as they are unable to undergo morphogenesis into tube-like structures in an in vitro assay of angiogenesis. Collectively, our data show that Dab2 plays a crucial role in VEGFR2 trafficking in the endocytic system and this impacts receptor signaling and endothelial cell morphogenesis during angiogenesis.

Neural tube defects (NTD) are among the most common birth defects and the leading cause of infant mortality. NTDs occur when the neural tube fails to close during early fetal development. The two most common types of NTD are spina bifida and anencephaly. NTDs result in lifelong complications like musculoskeletal deformities and loss of strength. The etiology of NTDs is complex and involves still unclear environmental and genetic factors. However, one of the well-established risk factors of NTDs is folic acid deficiency. The prevalence of NTDs can be lowered by an adequate intake of folic acid in the periconceptual period. In 1996, the Food and Drug Administration mandated that 140 micrograms of folic acid be added to 100 grams of bleached grain products with the goal of reducing the prevalence of NTDs. In the years following this fortification mandate, studies have shown that blood folate levels have more than doubled on average, that there are demographic and socioeconomic disparities in blood folate gains and that NTD rates have declined. However, no studies after the mandate have examined changes in blood folate distribution and differences in NTD prevalence by a wide range of theoretically and biologically relevant risk factors after the mandate. Using a nationally representative sample of non-institutionalized women of reproductive age, I investigated the relationship between the fortification mandate and blood folate levels. I also examined changes in the range/spread of blood folate distribution after the mandate. Using data on US live births from 45 states and the District of Colombia, the second study examined whether (1) the disparities in blood folate changes translate into differences in NTD prevalence and (2) NTD risk factors moderate the association between the mandate and NTD prevalence,. The final study explored potential unintended impacts of the mandate on birth weight, low birth weight, very low birth weight, high birth weight, and physician-diagnosed developmental delay, asthma and allergies. For this study, I employed samples from the Natality files and the National Survey for Children's Health. The cumulative results of my research suggested that the mandate was associated with increases in blood folate concentration, with greater increases in higher quantiles of the blood folate distribution and that the spread of blood folate distribution after the mandate widened. Additionally, the mandate was associated with a decrease in the prevalence of NTDs in the entire US population although the impact of the mandate was moderated by race/ethnicity, maternal educational attainment, acute illness during pregnancy and infant region of birth. Furthermore, the mandate was associated with other unintended infant and child health outcomes such as average birth weight increases in the population and increased risks of developmental delay among six year olds. This research is the first of its kind to examine changes in the spread of blood folate distribution after the mandate and whether NTD risk factors moderate the association between the mandate and NTD prevalence. It is also the first study to explore potential impacts of the actual mandate (not prenatal folic acid supplementation) on other unintended infant and child health outcomes. The results add significantly to our understanding of the effects of the mandate and have important implications for health care providers, women of reproductive age and policy makers because of the potentially increased risk of developmental delay among children and the increasing disparity in blood folate concentrations after the mandate.

As Tecnologias da Informação e Comunicação (TIC) são reconhecidas como ferramentas que estimulam o senso crítico, a reflexão e a autonomia na formação profissional em enfermagem, enquanto estratégia para fortalecimento da cultura de qualidade e segurança, visando à prevenção de incidentes relacionados à administração de medicamentos por sonda enteral. Este estudo retrata uma pesquisa de desenvolvimento ou Design-Based Research (DBR), com objetivo de desenvolver e avaliar uma tecnologia educacional sobre a temática de segurança na administração de medicamentos por sonda enteral. O Ambiente Virtual de Aprendizagem (AVA) foi desenvolvido em três etapas: 1) Planejamento; 2) Desenvolvimento e 3) Avaliação. Na Etapa 1, o planejamento contempla a caracterização do público-alvo, definição da temática e dos objetivos a serem alcançados. A Etapa 2 corresponde ao desenvolvimento da Tecnologia Educacional utilizando a metodologia WebQuest (Introdução, Tarefa, Processo, Avaliação, Conclusão e Créditos). Na Etapa 3 foi realizada a avaliação da tecnologia educacional digital por cinco profissionais da área de Informática e cinco enfermeiros docentes, mediante aprovação do projeto junto ao Comitê de Ética em Pesquisa. A pesquisa resultou no desenvolvimento de uma WebQuest curta sobre a temática de segurança do paciente, com enfoque na proposta de ações estratégicas visando a prevenção de erros e incidentes relacionados à administração de medicamentos por sonda enteral. A avaliação dos aspectos pedagógicos indicou que as características foram plenamente alcançadas em relação à Pertinência, Aplicabilidade e Consistência do Conteúdo; Interação Aluno-aluno, Aluno-grupo, Aluno-professor e Grupo-Professor; Pertinência, Quantidade e Avaliação Educacional das Atividades. Na avaliação dos aspectos técnicos, as características foram plenamente alcançadas em relação às Cores (Qualidade da Interface), segundo a opinião de todos os especialistas em enfermagem e em informática. As contribuições dos especialistas em relação às características parcialmente alcançadas e não alcançadas permitiram a realização de ajustes para implementação futura junto a estudantes do curso técnico em Enfermagem. Vale destacar que não foram relatadas características não alcançadas em relação aos aspectos pedagógicos. Os resultados evidenciam a relevância do domínio dos atributos próprios da WebQuest, visando a superação dos desafios relacionados ao desenvolvimento do pensamento crítico e aplicação de conhecimentos na solução de problemas vivenciados na busca por maior qualidade e segurança na assistência ao paciente, compatíveis com a exigências de ampliação do uso de tecnologias educacionais digitais inovadoras na formação profissional em enfermagem / Information and Communication Technologies (ICT) are recognized as tools that stimulate critical thinking, reflection and autonomy in professional nursing training, as a strategy to strengthen the culture of quality and safety, in order to prevent incidents related to the administration of medicines for enteral tube. This study describes a development research or Design-Based Research (DBR) aiming to develop and evaluate an educational technology on the theme of safety in the administration of medicines by enteral tube. The Virtual Learning Environment (VLE) was developed in three stages: 1) Planning; 2) Development and 3) Evaluation. In Step 1, the planning contemplates the characterization of the target audience, definition of the theme and the objectives to be achieved. The Step 2 corresponds to the development of Educational Technology using the WebQuest methodology (Introduction, Task, Process, Evaluation, Conclusion and Credits). In Step 3, the evaluation of the digital educational technology was carried out by five professionals in the area of Informatics and five nursing professors, after approval of the project by the Research Ethics Committee. The research resulted in the development of a short WebQuest on the subject of patient safety, with a focus on the proposal of strategic actions aimed at the prevention of errors and incidents related to the administration of medicines by enteral tube. The evaluation of pedagogical aspects indicated that the characteristics were fully achieved in relation to the Relevance, Applicability and Consistency of Content; Student-student interaction, Student-group, Student-teacher and Group-Teacher; Relevance, Quantity and Educational Evaluation of Activities. In the evaluation of the technical aspects, the characteristics were fully achieved in relation to the Colors (Quality of Interface), according to the opinion of all specialists in nursing and computer science. The experts\' contributions in relation to the partially achieved and unrealized characteristics allowed to make adjustments for future implementation with students of the technical course in Nursing. It is worth mentioning that there were no reported unrealized characteristics in relation to the pedagogical aspects. The results highlight the relevance of the domain of WebQuest attributes, aiming to overcome the challenges related to the development of critical thinking and application of knowledge in the solution of problems experienced in the search for higher quality and safety in patient care, compatible with the requirements of expansion of the use of innovative digital educational technologies in nursing professional training

Transport Membrane Condenser (TMC) is an innovative technology based on the property of a nano-scale porous material which can extract both waste heat and water from exhaust gases. This technology tremendously improves the efficiency of boilers and gas/coal combustors by lowering waste heat and increasing water recovery. Contaminants in the flue gases, such as CO2, O2, NOx, and SO2 are inhibited from passing through the membrane by the membrane’s high selectivity. The condensed water through these tubes is highly pure and can be used as the makeup water for many industrial applications. The goal of this research is to investigate the heat transfer, condensation rate, pressure drop and overall performance of crossflow heat exchangers. In this research, a numerical model has been developed to predict condensation of water vapor over and inside of nano-porous layers. Both capillary condensation inside the nanoscale porous structure of the TMC and the surface condensation were considered in the proposed method using a semi-empirical model. The transport of the water vapor and the latent heat of condensation were applied in the numerical model using the pertinent mass, momentum, turbulence and energy equations. By using the proposed model and simulation procedure, the effect of various inlet parameters such as inlet mass flow rate, inlet temperature, and water vapor content of the inlet flow on the performance of the cross-flow TMC heat exchanger was studied to obtain the optimum performance of the heat exchangers at different working conditions. The performance of the TMC heat exchangers for inlet flue gas rate 40 to 120 kg/h, inlet water rate 60 to 140 kg/h, inlet flue gas relative humidity 20 to 90%, and tube pitch ratio 0.25 to 2.25 has been studied. The obtained results show that the water condensation flux continuously increases with the increase of the inlet flue-gas flow rate, water flow rate, and the flue-gas humidity. The total heat flux also follows the same trend due to the pronounced effect of the latent heat transfer from the condensation process. The water condensation flux and the overall heat transfer increase at the beginning for small values of the tube pitches and then decreases as the tube pitch increases furthermore. In addition to the cross-flow TMC heat exchangers, the performance of a shell and tube TMC heat exchanger for high pressure and temperature oxy-combustion applications has been investigated. The performance analysis for a 6-heat exchanger TMC unit shows that heat transfer of the 2-stage TMC unit is higher than the 2-stage with the same number of the heat exchanger in each unit.

No description available.

Tonsillectomy, adenoidectomy and myringotomy are the most common surgical procedures undergone by children. Medical opinion regarding the appropriateness of these procedures remains contentious, and considerable resources have been expended in the formulation and distribution of relevant practice guidelines. The impact of this surgery on the child, community and private and public health resources is considerable, yet there has been little examination of surgery rates and trends, or of the characteristics of children who undergo surgery. This thesis addressed five major questions regarding this surgery in New South Wales, Australia. The first three related to population rates: the level of surgery among NSW children, comparability with international rates, trends over time and the effect of guidelines. Comprehensive hospital data between 1981 and 1999 were analysed. Major findings were a higher myringotomy rate in NSW than reported internationally, the short-term effect of guidelines, and a major shift towards children having surgery at a younger age. The remaining questions asked whether children who had surgery differed from other children in their use of health services prior to surgery, and if so, whether their utilization reverted to the norm following surgery. Matched records of a population cohort of 6239 NSW children, born during January 1990, were extracted from Health Insurance Commission data, and their claims for medical services followed retrospectively from birth to 8 years. Children who had privately funded surgery were found to use more medical services than other children, and, most unexpectedly, this did not change following surgery. The results suggest potential non-clinical factors influencing this excess utilization. This is the first population study to examine health service utilisation by these children and it has identified an important new risk factor for surgery.