Microtextures recorded on quartz sand grain surfaces provide evidence of past environment. Environmental processes, such as transport by glacial ice, create unique microtextures on sand grain surfaces that can be observed under high magnification with a scanning electron microscope. These microtextures and their proportions tend to be unique to environment type, allowing investigators to infer the environmental conditions to which sediments have been exposed, for example to distinguish sediments from fluvial versus mass-wasted environments. Microtextural evidence also allows inferences about the history of sediments of unknown origin. This thesis determines the qualitative and quantitative microtextural fingerprint of glacigenic quartz sand grains deposited by small tropical alpine glaciers in Costa Rica, and compares that fingerprint to the fingerprints of highland Dominican Republic sediments of uncertain genesis, to gauge whether those, individually or grouped, resemble the Costa Rican glacigenic samples. I selected 18 samples (9 each from Costa Rica and the Dominican Republic) and analyzed a minimum of 100 quartz sand grains per sample using a scanning electron microscope. My sample sizes were dictated by the scale of empirical 99% confidence intervals that would allow meaningful comparison of samples. Analysis using literature-recommended numbers of quartz sand grains would entail such large confidence intervals that practically any results would have been indistinguishable. I recorded the presence or absence of 25 microtextures on each grain, and calculated the percentage of each microtexture’s occurrence in the sample. The percentages constituted the sample’s microtextural fingerprint. As a whole, the Costa Rican fingerprints were very similar to each other, and so were the Dominican Republic fingerprints. Further comparison led me to conclude that the Dominican Republic samples are statistically indistinguishable from the Costa Rican glacierized samples. This thesis is part of a larger project establishing protocols for distinguishing glacigenic from non-glacigenic sediments, and testing for glacigenicity of sediments in Costa Rica, the Dominican Republic, and elsewhere. My results can be applied in other studies distinguishing tropical highland glacigenic and non-glacial samples. My contribution will hopefully contribute toward completion of the project’s goals, specifically determining the presence or absence of past glaciers in the Dominican Republic.

[pt] Neste trabalho são avaliados os parâmetros de transporte da bactéria Escherichia coli ATCC11229, microrganismo indicador de contaminação fecal, através de colunas de areia de quartzo saturadas. Com este propósito foi desenvolvido o equipamento para a execução dos ensaios Advecção-Dispersão-Sorção (ADS), com injeção contínua de uma suspensão bacteriana em água destilada em uma concentração inicial de 10 (8) bactérias/mL, por até doze horas em temperatura ambiente e sob condições que permitiram desprezar os efeitos do crescimento e decaimento dos microrganismos. Para a determinação dos parâmetros de transporte foram executados ensaios microbiológicos, ensaios de batelada e oito ensaios ADS para diferentes valores de gradiente hidráulico. Os ensaios de batelada mostraram uma baixa adsorção bactéria-solo nas condições avaliadas. As curvas de chegada obtidas nos ensaios ADS, mostraram elevados valores para o fator de retardamento entre três e nove, variando proporcionalmente com o incremento de gradiente hidráulico. Os valores de dispersão hidrodinâmica variaram entre 1,44x10(-2) cm(2)/min e 5,47x10(-2) cm(2)/min. Os resultados dos ensaios sugerem que os processos físico-químicos têm pouca influência no transporte deste microrganismo em areia de quartzo, enquanto que o processo de filtração mecânica, forças hidrodinâmicas, a forma e distribuição de tamanho dos grãos parecem explicar mais adequadamente o comportamento das curvas de chegada. / [en] This study deals with the assessment of the transport parameters of the Escherichia coli ATCC11229 bacteria, a fecal contamination indicator, through saturated quartz sand columns. With this purpose, it was developed an equipment to carrying out Advection-Dispersion-Sorption (ADS) experiments, with continuous input of bacterial distilled water suspension at an influent concentration of 10(8) cell/mL for about twelve hours, at environmental temperature and under conditions that allow disregard the effect of the growth and decay of the microorganisms. Microbiological experiments, batch tests, and eight ADS experiments at several hydraulic gradient values, were executed for determine the transport parameters. The batch tests indicated a low bacterium-soil adsorption under evaluated conditions. The breakthrough curves, obtained by ADS experiments, showed high values for the retardation factor, ranged from three to nine with increasing the hydraulic gradient. The hydrodynamic dispersion values ranged between 1,44x10(-2)cm(2)/min and 5,47x10(-2) cm(2)/min. The results of the experiments suggested that the physical-chemical processes have a little influence on the transport of this microorganism in quartz sand, whereas the straining process, hydrodynamic forces, the shape and grain distribution, would can explain more appropriately the behavior of the breakthrough curves.

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No. of bitstreams: 2 Tese - Fernando Ernesto Ucker - 2015.pdf: 2298051 bytes, checksum: d8ba74457fe737b3f2a05b9a4183e681 (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) Previous issue date: 2015-08-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the state of Goiás sugarcane cultivation has expanded into areas of sandy soil, known as fragile because of their high risk of degradation. Potassium is a vital nutrient used in the cultivation of sugarcane and has been applied to these cultivated soils. Little is known about the mobility of the potassium ion in such soils. This thesis set out to assess the vertical movement of potassium in Quartz-sand Neosols found in an area of the Araucária farm, in the municipality of Mineiros, Goiás, which is under two types of regime: sugarcane cultivation and Cerrado vegetation. The movement of this nutrient was studied on the basis of three experiments: 1st) a laboratory experiment with columns. Soil samples were sent to the Hydraulics Laboratory at the Pontifical Catholic University of Goiás where the experiment with columns was performed in triplicate for each type of soil management. Each 100 cm high column was sectioned into rings of 10 cm in height by 7.5 cm in diameter. A total of 105 mg of K2O, in the form of KCl, was applied to the surface layer. Over the next ten days, deionized water was applied to each column, the equivalent of 600 mm precipitation at the end. The leachate effluent was collected periodically and sent for potassium content analysis. At the end of the ten-day period, the columns were dismantled, and the soil in each ring was collected and sent for analysis of potassium, organic matter and pH levels. The mean values of potassium were submitted to descriptive analysis and a t test (α = 0.05); 2nd) a field experiment under two types of water regime, natural and controlled. In the natural water regime, rectangular metal troughs measuring 0.5 m2 were made. Three were installed in soil under sugarcane cultivation and another three in the same soil under Cerrado vegetation. Witness soil samples were collected in November 2013, before the onset of the rainy season in that region. After this initial collection, the equivalent of 120 kg ha-1 of K2O in the form of KCl was applied to the soil, and left for the full wet season, until the end of April of the following year. After that, soil samples were collected from the troughs at each level of 10 cm to a depth of 100 cm. The analysis of potassium movement under the controlled water regime took place in November 2013. The areas assessed were the same as those of the natural water regime. For this study concentric rings were used to delimit the area and ensure a vertical flow of the water applied. The equivalent of 600 mm of water was applied within the internal ring. After 24 hours the same amount of K+ as was applied in the natural regime and water equivalent to 600 mm of accumulated rain were applied. After 48 hours, soil sampling was carried out with a Dutch auger at levels of 10 cm to a depth of 100 cm. The soil samples collected in the field were sent for analysis in terms of total sand, silt, total clay, K+, pH and organic matter, and; 3rd) the field experiment with biennial evaluation of potassium movement. This experiment involved two parallel stretches of Quartz-sand Neosols along a slope, one with Cerrado vegetation and the other with sugarcane cultivation. In each of these stretches a transect with ten sampling points, each 30 m apart, was established and samples were collected at each point. Composite samples were collected in the two areas under study at depths of 0-20, 20-40, 40-60, 100-120 and 160-180 cm. After collection, the samples were bagged and appropriately identified, then forwarded for analysis to the Embrapa Soils Laboratory in Rio de Janeiro. The collections were made in November 2011 and 2012, the beginning of the rainy season in the region under study, and in April 2012 and 2013, the end of the rainy season, yielding a two-year evaluation period. In the laboratory, the samples were analyzed for cation exchange capacity, pH and organic matter, as well as for potassium. It was concluded from the first experiment that in the Quartz-sand Neosols there could be a significant loss of K+ after applying potassium to the soil. An increase of more than 1% in organic matter content could positively influence K+ retention in this type of soil. It was concluded from the second experiment that there was a significant movement of potassium levels to lower layers in the natural water regime after the accumulated rainfall of 1638 mm, both in the soil under cultivation and under Cerrado vegetation. From the third experiment it was concluded that the potassium ion behaved differently in the two soil regimes, sugarcane cultivation and Cerrado vegetation, and an increase in the nutrient was seen in layers of more than 100 cm in depth. / No Estado de Goiás o cultivo da cana-de-açúcar tem se expandido para áreas com solos arenosos, denominados frágeis por seus altos riscos a degradação. Potássio é um importante nutriente utilizado no cultivo da cana-de-açúcar e tem sido aplicado nesses solos sob cultivo. Pouco se conhece sobe a mobilidade do íon potássio em tais solos. Esta tese teve o objetivo de avaliar a movimentação vertical de potássio em Neossolo Quartzarênico encontrado em área da Fazenda Araucária, localizada na região do município de Mineiros-GO, que se encontra sob dois tipos de usos: sob o cultivo de cana-de-açúcar e sob vegetação de Cerrado. A movimentação deste nutriente foi estudada a partir de três experimentos: 1°) experimento laboratorial com colunas. Amostras de solo foram encaminhadas para o Laboratório de Hidráulica da Pontifícia Universidade Católica de Goiás onde o experimento com colunas foi realizado em triplicata para cada tipo de uso. Cada coluna possuía 100 cm de altura e foi seccionada em anéis de 10 cm de altura por 7,5 cm de diâmetro. Cada coluna recebeu acima da camada superficial, 105 mg de K+, na forma de KCl. Durante dez dias seguidos foi aplicada água deionizada em cada coluna, representando ao final uma precipitação de 600 mm. O efluente lixiviado foi coletado periodicamente e encaminhado para análise do teor de potássio. Ao final dos dez dias as colunas foram desmontadas e o solo foi coletado em cada anel e encaminhado para análise de teores de potássio, matéria orgânica e pH. As médias dos valores de potássio foram submetidas a análise descritiva e teste t (α = 0,05); 2°) experimento em campo sob dois tipos de regime hídrico, natural e controlado. No regime hídrico natural, calhas metálicas retangulares foram confeccionadas com área de 0,5 m2. Três calhas foram instaladas em solo sob cultivo com cana-de-açúcar e outras três calhas no mesmo solo sob Cerrado. Amostras de solo testemunhas foram coletadas em novembro de 2013, antes do início do período chuvoso na região. Após coleta inicial, foi aplicado sobre o solo o equivalente a 80 kg ha-1 de K+ na forma de KCl, e aguardou-se todo o período chuvoso, com fim em abril do ano seguinte. Após isto, amostras de solo foram coletadas no interior das calhas a cada 10 cm até a profundidade de 100 cm. A avaliação da movimentação de potássio sob regime hídrico controlado foi realizada em novembro de 2013 e as áreas avaliadas foram as mesmas do regime hídrico natural. Para esse estudo foram utilizados anéis concêntricos para delimitação da área e para garantir fluxo vertical da água aplicada. Aplicou-se no interior do anel interno o equivalente a 600 mm de água. Após 24 horas aplicou-se a mesma quantidade de K+ do regime natural e água equivalente a 600 mm de chuva acumulada. Após 48 horas procedeu-se a amostragem do solo a cada 10 cm até a profundidade de 100 cm com uso de trado holandês. As amostras de solo coletadas em campo foram encaminhadas para avaliação quanto aos teores de K+, pH e matéria orgânica e; 3º) experimento em campo com avaliação bianual da movimentação vertical do potássio. Nesse experimento foram considerados como tratamento duas faixas paralelas de um Neossolo Quartzarênico dispostas ao longo da vertente, sendo uma com vegetação de Cerrado e outra com cultivo de cana-de-açúcar. Em cada uma das faixas foi estabelecido um transecto com dez pontos de amostragem, espaçados de 30 m entre si, onde repetiu-se a coleta de amostras em cada ponto. Amostras compostas foram coletadas nas duas áreas estudadas nas profundidades de 0-20, 20-40, 40-60, 100-120 e 160-180 cm. Após a coleta, as amostras foram ensacadas e devidamente identificadas, sendo então encaminhadas ao Laboratório de Solos da Embrapa Solos – RJ para análise. As coletas ocorreram em novembro de 2011 e 2012, período que significa início da estação chuvosa na região de estudo e abril de 2012 e 2013, período correspondente ao final da estação chuvosa, totalizando dois anos de avaliação. Em laboratório, as amostras foram submetidas à análise da capacidade de troca catiônica, pH e matéria orgânica, além de potássio. Do primeiro experimento concluiu-se que em Neossolo Quartzarênico pode haver significativa perda de K+ após aplicação de potássio no solo. O aumento do teor de matéria orgânica acima de 1% pode influenciar positivamente a retenção de K+ neste tipo de solo. Do segundo experimento concluiu-se que houve movimento significativo dos teores de potássio para camadas inferiores em regime hídrico natural após precipitação acumulada de 1.638 mm, tanto no solo sob lavoura quanto no solo sob Cerrado. Já do terceiro experimento concluiu-se que o íon potássio teve comportamento distinto para o solo cultivado com cana-de-açúcar em relação ao solo sob Cerrado, e verificou-se acréscimo do nutriente em camadas superiores a 100 cm de profundidade.

<p> Cobequid Bay is a macrotidal embayment with a large intertidal sand bar complex at the east end, located at the head of the Bay of Fundy. Two sand bars were sampled in order to observe variations in impact pit densities on the surfaces of quartz sand grains, and to identify the pattern of grain size distribution over two intertidal bedforms. </p> <p> V pit densities obtained by viewing the quartz grain surfaces at magnifications of 10,000 and 5,000X with a scanning electron microscope indicate a linear correlation with grain size. The number of small V's appears to be consistent for all grain sizes, with the result that V's larger than approximately 1/5 micrometer produce the linear variation noted. Two trends of V pits formation combine to produce a "plateau", in which two grain size classes have similar V pit densities. This plateau corresponds to the break-point between the traction population and the intermittent suspension population. Trend one consists of the bombardment of large, well exposed grains (transported in the traction layer), by smaller saltating grains, while trend two consists of grain impacts between smaller grains in the concentrated "rheological layer". </p> <p> Two different grain size patterns were discovered on the two sampled bedforms. A fining upward trend toward the crest on both the stoss and slip faces was observed on an ebb dominated megaripple on Selmah Bar. The exact opposite pattern was noted on an ebb dominated sandwave from East Noel Bar. On this bedform, an upward coarsening trend toward the crest was discovered on both the stoss and slip faces. These two patterns correspond to the patterns observed by Dalrymple (1977) in his studies of intertidal bedforms. </p> / Thesis / Bachelor of Science (BSc)

Целью магистерской диссертации является разработка состава массы для производства глазурованного керамического гранита. В работе исследованы свойства сырьевых материалов. Определены технологические параметры производства и разработана технология производства для производства глазурованного керамического гранита. / The aim of the master's thesis is to develop the composition of the mass for the glazed ceramic granite production. The paper investigated the properties of raw materials. The technological parameters of production are determined and the production technology for the production of glazed ceramic granite is developed.