Extreme temperatures have increasingly played an important role in engineering applications, including leading edges during hypersonic flight, spacecraft re-entry, and propulsion systems. In order to design for such thermo-mechanical conditions, materials must be characterized using suitable measurement methods. DIC is a popular and versatile method in full-field measurement. In brief, DIC compares images of a sample between its undeformed and deformed state in order to get displacement and strain field maps. Since the images are acquired from digital cameras, it is important to have high contrast images for meaningful correlation. Exposure time is a pivotal camera setting relating to camera sensitivity. Alteration in exposure time results in variation of image contrast, thereby affecting DIC correlation. Also, it is well known that at extreme temperatures, materials emit light which can saturate DIC camera sensors, but the light can be mitigated using optical bandpass filters. In previous work, many have shown that blue bandpass filters can effectively extend the temperature range of DIC, and our lab has shown that ultraviolet (UV) filters can extend the range further. In this thesis, four different temperatures: room temperature, 1300°C, 1450°C, and 1600°C were tested by rigid-motion experiments. At each temperature level, UV images were acquired in order to examine the variation of DIC error over the whole range of exposure time. UV images were acquired at exposure times ranging from 500μs to 61,000μs, which are the minimum and maximum possible values for the cameras used in this thesis. The results showed that there were higher errors of UV-DIC at extremely dark or bright exposure times where as errors were generally insignificant at intermediate exposure times. In order to perform meaningful DIC up to 1600oC, the exposure time for the camera used in this thesis is suggested to be set between 10,000μs and 40,000μs.

Neste trabalho estudou-se a variação da área de contato de hemiesferas de borracha contra uma superfície plana de vidro, variando-se a força de compressão aplicada, o tempo de aplicação da força e a força de separação das superfícies em contato. Os experimentos foram realizados com quatro borrachas de módulos de elasticidade 16,8, 5,77, 5,42 e 2,64 MPa e durezas de 87, 68, 57 e 44 Shore A, respectivamente. Para borrachas de dureza mais elevada, a variação da área de contato é menor para um mesmo carregamento de referência. Para borrachas com maior módulo viscoso, maior é a variação da área de contato em função do tempo de exposição e maior a força de separação entre as superfícies. Os resultados reafirmam o modelo de Jonhson, Kendall e Roberts para o contato com baixos carregamentos de esferas de borracha e contribui para o entendimento da área de contato em função do tempo de exposição ao carregamento, onde a variação chegou a 23% para a borracha de maior módulo viscoso. / Contact area variation and separation forces of rubber hemispheres against a flat glass plate were studied with increasing normal forces and load exposure time. The experiments were performed on four different rubbers with Youngs modulus of 16.8, 5.77, 5.42 e 2.64 MPa and hardness of 87, 68, 57and 44 Shore A, respectively. For higher hardness rubbers, the contact area variation is smaller for the same load parameters. For higher viscous modulus rubber, the contact area variation over time is higher and it is also higher the surface separation force required. The results found are in agreement with Johnson, Kendall and Roberts model for the contact at low loads of rubber spheres and it does a contribution for the understanding of contact area due to load exposure time where variation reached up to 23% for the higher viscous modulus rubber.

Thesis (M.S.P.H.)--Uniformed Services University of the Health Sciences, 2006 / Typescript (photocopy)

Oyster shells are normally applied in wastewater treatment in the form of a powder; but the possibility of whole oyster shells removing metal ions in stormwater has not been investigated. The objectives of this research are to assess the application of whole oyster shells for removing metals in low concentration solutions and to explore the influence of the following factors: surface area of shells, initial concentration and exposure time, on removal efficiency. Experimental results demonstrated very good removal efficiency by oyster shells for removing copper, followed by cadmium and zinc; but was not effective in hexavalent chromium removal. Up to 70% removal can be reached in just one hour for copper with initial concentrations of 0.2ppm with 550cm2 of surface area (SA) of shells in a beaker experiment treating two-liter solutions (with an accompanying pH increase from 5 to 6.42). A removal efficiency (RE) of 57.7% and 33.3% was found for cadmium and zinc, respectively, with one day contact using shells of 300cm2 SA treating one liter of the lowest concentration solution; while only 14.3% was achieved for chromium under the same conditions. Mid-scale experiments with continuous inflow based on the 6-hour Saanich Design Storm demonstrated an 85.5% and an 83.9% RE of cadmium and copper in one day’s worth of contact time. There was no removal but in fact an increase in chromium and zinc was found for the mid-scale experiment. There was a positive relationship between initial concentration (IC) and removal efficiency for copper and zinc, but a negative relationship for chromium, while no relationship was found for cadmium. Up to 80% of copper can be removed at IC of 2.4ppm compared to 60% with IC of 0.65ppm with same amount of shells (by surface area). RE of 70%, 75% and 83% was observed for IC of 0.3ppm, 0.58ppm and 1.07ppm for zinc, respectively, with 154 cm2 SA. When IC of chromium is reduced from 1 ppm to 0.2ppm, RE tends to drop from 60% to 26%. There was also a positive relationship between SA and RE, and ET and RE. However, after a certain exposure time, increase in RE was negligible and sometimes, desorption would occur. Additionally, when the difference in surface area is small, the influence of this factor on RE was also small. When treating certain ranges of solution concentration, the effect of surface area on RE is difficult to distinguish. Moreover, the role of HRT in stormwater systems was not clearly found. / Graduate

Orientador: Paulo Sérgio Flores Campos / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T13:43:28Z (GMT). No. of bitstreams: 1 Melo_DanielaPitade_D.pdf: 3502818 bytes, checksum: b21f46341d5b0efd39ab5d74543853fe (MD5) Previous issue date: 2010 / Resumo: O objetivo, neste trabalho, foi verificar se diferentes tempos de exposição interferem no diagnóstico de cáries proximais e no valor médio do pixel da imagem do sistema Schick CDR Wireless. Foram obtidas imagens de 10 phantoms, constituídos de dentes humanos, e de uma escala de alumínio utilizando-se diferentes tempos de exposição. Os oito tempos de exposição estudados foram em ordem crescente: 0,06s, 0,1s, 0,13s, 0,16s, 0,2s, 0,25s, 0,3s e 0,35s. As imagens dos phantoms obtidas com os tempos selecionados foram interpretadas por quatro avaliadores quanto à presença de cárie proximal. Cada avaliador atribuiu um escore para cada uma das faces dentárias interpretadas. Esses escores foram posteriormente comparados aos cortes histológicos. Os tempos de exposição foram avaliados, quanto à sua acurácia no diagnóstico de cárie, por meio da curva ROC. As imagens obtidas da escala de Al em diferentes tempos de exposição tiveram o valor médio do pixel mensurado utilizando-se a ferramenta apropriada do software EMAGO®/Advanced. As médias das curvas ROC correspondentes aos tempos de exposição avaliados variaram de 0,53 a 0,62, sendo que a faixa de tempos que apresentou melhor resultado variou de 0,06s a 0,25s; destes, o tempo 0,25s obteve o melhor resultado. Quanto ao valor médio do pixel, foram observados dois comportamentos distintos nos tempos estudados, entretanto, o tempo de 0,20s apresentou valor médio do pixel nas duas fases comportamentais. O desempenho dos tempos de exposição entre 0,06s e 0,25s foi satisfatório no diagnóstico de cáries proximais, sendo o tempo 0,25s o mais indicado para essa finalidade / Abstract: The aim on this study was to evaluate the influence of different exposure times on proximal caries detection and on mean pixel values of the Schick CDR Wireless digital image. Ten human teeth phantoms and an aluminum scale were radiographed using different exposure times. The eight studied exposure times were: 0.06s, 0.1s, 0.13s, 0.16s, 0.2s, 0.25s, 0.3s and 0.35s.The images of them phantoms in different exposure times were evaluated by four observers for the presence of caries lesions. Each observer scored the proximal surfaces of each tooth. The scores were compared to the golden standard. The exposure times were evaluated on their accuracy of predicting caries by means of the ROC curve analysis. The images of the aluminum scale using different exposure times had their mean pixel values measured using the appropriate tool of the EMAGO®/Advanced software. The means of the ROC curves of each exposure time evaluated varied from 0.53 to 0.62, and the exposure time range between 0.06s to 0.25s presented better results, and the exposure time of 0.25s presented the highest Az from them. In regard to mean pixel values, two different behaviors were observed, and the exposure time of 0,20s presented mean pixels values in the two behavior phases. The behavior of the exposure times from 0.06s to 0.25s was satisfactory for proximal caries detection, and 0.25s is better indicated for this finality / Doutorado / Radiologia Odontologica / Doutor em Radiologia Odontológica

Neste trabalho estudou-se a variação da área de contato de hemiesferas de borracha contra uma superfície plana de vidro, variando-se a força de compressão aplicada, o tempo de aplicação da força e a força de separação das superfícies em contato. Os experimentos foram realizados com quatro borrachas de módulos de elasticidade 16,8, 5,77, 5,42 e 2,64 MPa e durezas de 87, 68, 57 e 44 Shore A, respectivamente. Para borrachas de dureza mais elevada, a variação da área de contato é menor para um mesmo carregamento de referência. Para borrachas com maior módulo viscoso, maior é a variação da área de contato em função do tempo de exposição e maior a força de separação entre as superfícies. Os resultados reafirmam o modelo de Jonhson, Kendall e Roberts para o contato com baixos carregamentos de esferas de borracha e contribui para o entendimento da área de contato em função do tempo de exposição ao carregamento, onde a variação chegou a 23% para a borracha de maior módulo viscoso. / Contact area variation and separation forces of rubber hemispheres against a flat glass plate were studied with increasing normal forces and load exposure time. The experiments were performed on four different rubbers with Youngs modulus of 16.8, 5.77, 5.42 e 2.64 MPa and hardness of 87, 68, 57and 44 Shore A, respectively. For higher hardness rubbers, the contact area variation is smaller for the same load parameters. For higher viscous modulus rubber, the contact area variation over time is higher and it is also higher the surface separation force required. The results found are in agreement with Johnson, Kendall and Roberts model for the contact at low loads of rubber spheres and it does a contribution for the understanding of contact area due to load exposure time where variation reached up to 23% for the higher viscous modulus rubber.

Orientador: Herling Gregorio Aguilar Alonzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T06:53:40Z (GMT). No. of bitstreams: 1 Cabral_ElizabethReginadeMelo_M.pdf: 1914359 bytes, checksum: d409b490e5d371f9dcde7ee768da8976 (MD5) Previous issue date: 2012 / Resumo: Introdução: No Brasil, a utilização intensiva de agrotóxicos teve início com o II Plano Nacional de Desenvolvimento (1975-1979), que estimulava compulsoriamente a compra desses produtos pelos agricultores por meio de créditos rurais. Hoje, o país é considerado o maior consumidor de agrotóxicos do mundo. Na agricultura, a utilização deste produto é intensiva e multiquímica e pesquisas relacionadas à exposição a longo prazo aos agrotóxicos são escassas, tanto no conhecimento da extensão da carga química de exposição ocupacional, quanto aos danos à saúde. Objetivo: Determinar as características da exposição a longo prazo a agrotóxicos e suas implicações na saúde dos trabalhadores agrícolas de uma região de Campinas-SP. Método: Trata-se de um estudo descritivo transversal realizado em uma região do Distrito de Saúde Norte, do município de Campinas-SP. Foi realizado o arrolamento dos estabelecimentos e trabalhadores agrícolas. Utilizou-se um questionário semiestruturado abordando variáveis socioeconômicas, demográficas e sobre as condições de saúde, as condições de trabalho, o uso de agrotóxicos, episódios de intoxicação e a dosagem das colinesterases. Para o tempo de exposição aos agrotóxicos criou-se um Índice de Exposição, que quantificou e uniformizou o tempo em categorias (baixa, média, alta e muito alta exposição). Resultados: Participaram do estudo 36 estabelecimentos agrícolas e 205 trabalhadores. O número de trabalhadores que recusaram e/ou foi excluído do estudo perfizeram um total de 14,9%. A população estudada foi constituída predominantemente por adultos jovens do sexo masculino, assalariados (66,8%) e que desenvolvem atividades agrícolas com exposição a agrotóxicos há mais de 10 anos (63,9%). Dentre os trabalhadores, 11,7% relataram um episódio de intoxicação por agrotóxicos e 2% nos últimos 12 meses anteriores à pesquisa. Foram citados 144 nomes comerciais de agrotóxicos, aos quais os trabalhadores foram expostos, isso deu uma média de 4,1 tipos de agrotóxicos (IC 95% 3,9 - 4,6; dp= 3). Quanto às classes de uso, as mais relatadas foram os inseticidas, com 26,4%, seguidos dos fungicidas (20,7%), e herbicidas (20,1%). Apenas 29,2% dos trabalhadores relataram utilizar equipamentos de proteção individual. O tempo médio de exposição aos agrotóxicos foi de 13.611horas (IC 95% ± 3.672 horas), o valor mínimo foi de 44,3h, o valor até o primeiro quartil representou 846h, a mediana representou 4.200h, o terceiro quartil foi de 15.120h e, o valor máximo, de 203.520h de exposição. Nos últimos 12 meses anteriores, 75,6% dos trabalhadores apresentaram alguma sintomatologia relacionada ao uso de agrotóxicos. Irritação ocular (38,1%), dor de cabeça (37,4%) e lacrimejamento (25,2%) foram os sintomas mais referidos. Quanto à dosagem das colinesterases plasmáticas, 7,8% apresentaram redução da atividade. Conclusão: A ocorrência de intoxicações por agrotóxicos esteve dentro do esperado, quando comparado com outros estudos realizados no Brasil. O Índice de Exposição pode ser considerado um método para o estudo das exposições a logo prazo. Com a análise das informações levantadas, dos escassos dados epidemiológicos disponíveis, da avaliação de risco/vulnerabilidade e poder de decisão das populações expostas aos agrotóxicos, percebe-se que as repostas do setor saúde não acompanharam o ritmo, acelerado, de crescimento do setor agropecuário / Abstract: Introduction: In Brazil, the intensive use of pesticides began with the Second National Development Plan (1975-1979), which stimulated compulsorily purchase of such products by farmers through rural credit. Nowadays, the country is considered the largest consumer of pesticides in the world. In agriculture, the use of this product is intensive and multichemical and research related to long-term exposure to pesticides are scarce, both in knowledge of the extent of the chemical burden of occupational exposure, the damage to health. Objective: To determine the characteristics of long-term exposure to pesticides and their implications for the health of farm workers in a region of Campinas. Method: This is a cross-sectional study conducted in a region of the Northern Health District, the city of Campinas. We conducted the inventory of the establishments and agricultural workers. We used a semistructured questionnaire covering socioeconomic, demographic and health conditions, working conditions, the use of pesticides, intoxications and determination of the cholinesterase. For the duration of exposure to pesticides was created an exposure index, which quantified the time and standardized categories (low, medium, high and very high exposure). Results: There were 36 farms and 205 workers. The number of workers who refused and / or was excluded from the study amounted to a total of 14.9%. The study population consisted predominantly of young adult male employees (66.8%) and agricultural activities that develop with exposure to pesticides for over 10 years (63.9%). Among workers, 11.7% reported an episode of pesticide poisoning and 2% in the last 12 months preceding the survey. 144 were cited trade names of pesticides to which workers were exposed, this gave an average of 4.1 different types of pesticides (CI 3.9 to 4.6, SD = 3). The classes use the most pesticides were reported, with 26.4%, followed by fungicides (20.7%) and herbicides (20.1%). Only 29.2% of workers reported using personal protective equipment. The mean duration of exposure to pesticides was 13.611horas (CI ± 3672 hours), the minimum value was 44.3 h, the value represented by the first quartile 846h, the median represented 4.200h, the third quartile was 15.120he, the maximum value of 203.520h exposure. Over the past 12 months, 75.6% of workers had some symptoms related to pesticide use. Eye irritation (38.1%), headache (37.4%) and tearing (25.2%) were the most reported symptoms. As for the dosage of plasma cholinesterase, 7.8% had decreased activity. Conclusion: The occurrence of pesticide poisoning was as expected, when compared with other studies in Brazil. The index of exposure can be considered a method to study the term exposure to right. By analyzing the information gathered, the scarce available epidemiological data, risk assessment / vulnerability and empowerment of populations exposed to pesticides, it is clear that the responses of the health sector have not kept pace, accelerated growth of the agricultural sector / Mestrado / Epidemiologia / Mestre em Saúde Pública

Design methods for side shear of drilled shafts, including the resistance factors that should be applied, do not account for any specific construction procedure. Instead, design often relies on analysis of case studies which include all construction methods used in each geomaterial type (e.g. clays, sands and rocks), or on parametric analysis. Nonetheless, literature suggests that different construction procedures result in varying side shear. This research investigated 2 types of construction: (1) slurry stabilization in sandy soils using bentonite and polymer products that are commonly used on the field, with exposure times from near 0h to 96h, and (2) temporary casing stabilization in simulated limestone using 3 different methods for installation and extraction of the casings which included: driven, coarse-tooth rotated and fine-tooth rotated. All specimens were 1/10th scale in relation to the most common shafts sizes constructed in the field. The results showed that bentonite slurry causes a significant reduction on the side shear within relatively short periods of time (between 2h and 4h of open excavation), whereas polymer slurry did not show appreciable variations up to 96h. The driven and coarse-tooth rotated temporary casing exhibited lower side shear resistance than the fine-tooth rotated casings, which can be attributed to the larger annulus outside the casing and the additional crumbled pieces of rock that degrades the contact interface with the socket concrete. Construction-based resistance factors are suggested for each construction procedure investigated in this study and clearly show the effects from different methods.

Drilled shafts are cylindrical deep foundations constructed by casting fluid concrete into an excavated hole. These elements rely largely on side shear resistance generated by their substantial diameters and lengths to effectively transfer loads. Therefore, an exceptional concrete to soil interface is essential for proper performance of these structures. The FDOT preferred stabilization fluid, bentonite slurry, has been proven to degrade this interface with increased exposure time due to filter cake formation. For this reason, slurry exposure time has been limited to 36 hours by FDOT. Alternately, polymer slurries do not form a filter cake but rather stabilize excavations through continuous soil infiltration and the associated cohesion that accompanies the slurry presence. As polymer slurry use is relatively new to the state of Florida, FDOT does not presently have clear specifications regarding polymer exposure time limits. Hence, this thesis presents the results of pullout tests performed on 1/10th scale drilled shafts constructed with both polymer and bentonite slurries and with varying exposure times. To explore the effect of exposure time on side shear resistance, 24 - 4in diameter 8ft long shafts were constructed: 6 with bentonite and 18 with three different polymer products (6 each). After being exposed to the respective slurry for 0, 1, 2, 4, 8 or 24 hours, each excavated hole was concreted and tested after 7 days of curing. Pullout tests served as a direct measure of side shear resistance due to the absence of base resistance associated with compression testing. After testing, shafts were exhumed and sectioned for filter cake measurement. As expected, shafts constructed using bentonite slurries immediately exhibited a decrease in capacity with increased exposure time. Between 0 and 24 hours a 34% reduction in capacity was witnessed. These reductions were attributed to filter cake thickness which increased with exposure time along with the reduction in effective shaft. After 4 hours of exposure, side shear resistance for the bentonite shafts approached an asymptote, likely defined by the strength of the filter cake formed. The side shear resistance of all polymer shafts exceeded that of the 24hr bentonite control shaft by 20-50 percent depending on the polymer product used. For a given polymer product no capacity reduction was noted with respect to time. Inspection of exhumed shafts revealed the formation of a soil cake (region of stabilized soil stuck to the shaft) around the perimeter of the polymer shafts. Therefore, the side shear resistance of the polymer shafts was defined by the soil-to-soil interface surrounding the shaft and not by an intermediate filter cake. The study resulted in the following findings: (1) open excavations using polymer slurry stabilization are not adversely affected by extended exposure time, (2) the effect of filter cake formation in bentonite supported excavations slows with time whereby no significant degradation in capacity was noted after 8 hours, (3) shafts constructed with polymer slurry performed better than those constructed with bentonite, and (4) as polymer slurry flow into the surrounding soil does not slow with time, more slurry volume is required (compared with bentonite) and slurry level must be continuously maintained.

Orientador: Marco Eustáquio de Sá / Resumo: A utilização de testes de vigor, que sejam eficientes no diagnóstico da qualidade das sementes, é de vital importância no sucesso da agricultura. Nesse sentido, a utilização de metodologias que sejam mais adequadas à determinadas espécies é uma ferramenta importante para ser utilizada nos testes de vigor, visando realizar uma avaliação apurada da qualidade das sementes. Assim, objetivou-se estudar se as variações na realização do teste de envelhecimento acelerado, em termos de tempo de exposição e temperatura, realizado na forma tradicional ou em solução salina, resultaria numa combinação eficiente para avaliar a qualidade fisiológica de sementes de tomilho (Thymus vulgaris L.) e mini tomate (Solanum lycopersicum var. cerasiforme). Foi utilizado o delineamento inteiramente casualizado com os tratamentos obtidos da combinação temperaturas (36, 38, 40 e 42 ºC) x tempo de exposição (24, 36, 48 e 72 horas) x procedimentos (tradicional e solução salina), com quatro repetições para cada lote. As médias foram comparadas pelo teste de Tukey a 5% de probabilidade. Determinou-se também o coeficiente de correlação simples (r) entre os resultados dos testes de envelhecimento acelerado e o teste de emergência de plântulas em substrato. Tanto o tempo de exposição como a temperatura, foram fatores que afetaram o desempenho das sementes, de modo geral reduzindo-o com o aumento da temperatura. O uso da solução salina, permitiu a utilização de determinada temperatura por maior espaço de tempo,... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of vigor tests, which are efficient in the diagnosis of seed quality, is of vital importance in the success of agriculture. In this sense, the use of methodologies, which are more appropriate to certain species, is an important tool to be used in the vigor tests, aiming at an accurate evaluation of the seeds quality. The aim of this study was to study whether the variations in the performance of the accelerated aging test, in terms of exposure time and temperature, in the traditional form or in saline solution, would result in an efficient combination to evaluate the physiological quality of thyme seeds (Thymus vulgaris L.) and tiny tomato (Solanum lycopersicum var. cerasiforme). It was used a completely randomized design with the treatments obtained from the combination of temperatures (36, 38, 40 and 42 ºC) x exposure time (24, 36, 48 and 72 hours) x procedure (traditional and saline solution) repetitions for each batch. The averages were compared by the Tukey test at 5% probability. The simple correlation coefficient (r) between the accelerated aging test results and the emergence test of substrate seedlings was also determined. Both the exposure time and temperature were factors that affected seed performance, generally reducing it with increasing temperature. The use of saline allowed the use of a certain temperature for a longer period, without drastically reducing the results. / Mestre