Increased land use change near fragile ecosystems can affect the ecosystem energy balance leading to increased global warming. One component of surface energy balance is soil storage heat flux. In past work, a complex thermal behavior was noticed in the shrink-swell sediment of the upper Nueces Delta (upper Rincon) during summer months as it dried. Soil storage heat flux was found to first increase, then decrease, as the soil dried. It was suggested that the complex behavior was due to the relationship between thermal diffusivity and soil moisture, where thermal diffusivity increases to a local maximum before decreasing with respect to decreasing soil moisture. This study explores the observed phenomenon in a controlled laboratory environment by relating the sediment shrinkage curve to changing heat transfer properties. Due to the complicated nature of the drying-shrinking sediment, it was necessary to measure the sediment shrinkage curve and heat transfer properties in separate experiments. The shrinkage curve was found by correlating measured sample volume with gravimetric moisture content. Heat transfer properties were found using a single needle heat pulse probe. A normalized gravimetric moisture content was used as a common variable to relate the shrinkage curve and heat transfer data. Data suggests that the shrink-swell Rincon sediment portrays different behavior in drying than that which occurs for a non-shrink-swell soil. For the shrink-swell Rincon sediment, thermal conductivity is seen to increase with decreasing moisture, the suggested mechanism being increased surface area contact between particles as the shrinking sediment dries.

The swell waves which are an important component of wind generated waves have significant effects on small craft and fisheries. The swell wave climate has an important role in the design and operation of fishing harbors and harbors for small craft. Despite this fact the swell wave climate is not well known for the Turkish coasts. The purpose of the present study was to identify the swell wave climate along the Aegean and Mediterranean Sea coastline of T&uuml / rkiye. For this purpose wind and swell wave data for a 72 months period is obtained from ECMWF for the analysis. And the data are analyzed for twenty one locations selected along the Turkish coast. For every location the wind and swell wave roses, significant swell wave height versus Mean period of primary swell relations, extreme probability distribution and log-linear cumulative probability distribution are presented. Also some extreme swell events in the Aegean and Mediterranean Sea occurred in the data period are presented for a better understanding of generation and propagation of swell waves. The results showed that the swell wave activity and severity is higher in the Aegean and Mediterranean Sea coastline of T&uuml / rkiye. The investigation of extreme swell events provided that the swell waves occur and diminish in a relatively short duration and the data available from ECMWF which is provided for 12 hour intervals is not sensitive to time enough for the investigation of swell wave occurrence and propagation. The significant swell wave height versus Mean period of primary swell relations and analysis on period of swell waves showed that the swell wave periods could reach up to 12 seconds in the Western and Southern shores of T&uuml / rkiye.

No description available.

Austin, Texas consists of highly expansive soils that have caused failures in many structures. Minimizing the detrimental effects of expansive soils on structures requires that the swelling of these soil(s) is quantified accurately, efficiently, and timely. A testing procedure was developed to directly measure soil swelling using centrifuge technology by Plaisted, 2009. This testing procedure was developed in order to reduce the test duration while generating more swelling data relative to conventional tests that directly measure swell. However, the new procedure was incapable of obtaining in-flight swell data, resulting in the need to develop a procedure to directly measure swell during centrifugation. The objectives of this study were to update the testing procedure developed by Plaisted, 2009 by incorporating the use of an in-flight Data Acquisition System (DAS) that would produce accurate and repeatable results; and use the updated testing procedure to quantify the effects of compaction conditions on swelling for three expansive soils in the Austin area (Eagle Ford Shale, Houston Black Clay, and Taylor Clay). A DAS consisting of linear position sensors, analog to digital converters, JeeNode Arduinos, and an accelerometer was developed and installed within the centrifuge. Specimens were compacted at various water contents, and densities, and subjected to different g-levels. The effects of g-level, compaction water content, compaction dry unit weight, and soil type were determined by comparing the 34 hour swell percentages for the compacted specimens. The results of this study showed that in-flight monitoring of clay swelling could be successfully implemented in a comparatively small centrifuge, and that the data collected from the DAS was accurate and repeatable. Swelling of tested soils was found to be sensitive to changes in water content around optimum, with specimens compacted wet of optimum swelling less than specimens compacted dry of optimum. A 6% increase in relative compaction was found to negligibly affect the swelling. Finally, variations in confinement and compaction conditions were found to have a greater effect on swelling for soils that are more expansive in nature compared to soils less expansive in nature. / text

Expansive clays are located world wide and cause billions of dollars in damage each year. Currently, the expansion is usually estimated using correlations instead of direct testing as direct testing is expensive and often takes over a month to complete. The purpose of this study was to determine if centrifuge technology could be used to characterize expansive clays through direct testing. Testing was performed in an centrifuge permeameter on compacted specimens of Eagle Ford clay. A framework was developed to analyze effective stresses in centrifuge samples and methods were proposed to determine the swell-stress curve of a soil from centrifuge tests. Standard free swell test were also performed for comparison. The swell-stress curve determined by centrifuge testing was found to match with the curve found from free swell tests after correcting for differences in testing procedures. The centrifuge tests were found to be repeatable and required several days for testing rather than weeks. / text

The characterization of the swell potential of expansive clay is complicated by the fact that traditional swell testing methods require an excessive amount of time for specimens to swell to their maximum heights. As a result, the practicing engineer has typically referred to correlations between swell potential and index properties rather than directly measuring swelling in a laboratory experiment. The purpose of this study is to evaluate an alternate testing method using a geotechnical centrifuge in an attempt to decrease the time required to evaluate the swell potential of expansive clays so that expermientally obtained swelling properties may be obtained within a reasonable time period. This study includes an experimental program involving a series of tests in which compacted clay specimens are flown in a cetrifuge and their heights are monitored as water infiltrates into them. / text

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-05T12:03:40Z No. of bitstreams: 2 Dissertação BEZERRA,C. S. 2013.pdf: 7476726 bytes, checksum: 97af6d034dd0d2747df21f2cfd5e7912 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-05T12:03:40Z (GMT). No. of bitstreams: 2 Dissertação BEZERRA,C. S. 2013.pdf: 7476726 bytes, checksum: 97af6d034dd0d2747df21f2cfd5e7912 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / CNPq / As ondas e correntes representam a mais constante forma de transporte de energia no mar, fornecendo energia para uma vasta gama de processos litorâneos os quais exercem papel preponderante na morfologia da linha de costa e, por conseguinte na determinação das feições litorâneas. Além disso, representam ameaça às construções costeiras, às atividades de lazer e às operações navais. Diante deste cenário a presente dissertação de mestrado pretende contribuir através da análise temporal e espacial das ondas wind sea e swell, assim como das correntes atuantes no litoral de Boa Viagem (Recife – PE), a partir de dados de parâmetros físicos de ondas (altura máxima – Hmax, altura significativa – Hs, Período de pico – Tp, e direção média –  ) e correntes (direção e intensidade), os quais foram obtidos a partir de imagens polares de radar náutico de banda-X, gerados a partir de um sistema denominado Wave and Surface Current Monitoring System - WaMoS II. O radar esteve em funcionamento entre o mês de abril de 2010 a abril de 2011. A partir das análises realizadas foi possível observar a ocorrência conjunta de ondas do tipo wind sea e swell no litoral de Boa Viagem, sendo que esta última foi bastante expressiva nos meses de junho e outubro de 2010, além dos meses entre dezembro de 2010 a março de 2011, sendo provenientes em sua maioria de leste. As ondas wind sea apresentaram uma altura significativa predominante entre 1 e 2 m, sendo provenientes de leste-sudeste. Além disso, foi possível observar uma variação na direção e diminuição na altura das ondas ao longo da plataforma interna de Boa Viagem, causadas pela variação na batimetria e pela presença de recifes de arenito. Para as correntes não se observou diferença na direção das mesmas nas duas áreas de análise, porém no que se refere a intensidade, esta foi maior na área mais afastada da costa (área 3) do que na área sobre o canal (área 1). De uma forma geral, neste trabalho foi possível identificar as características predominantes, em cada mês ao longo de todo período estudado, das ondas wind sea, as quais estão sempre presente no litoral de Boa Viagem, bem como as características de swell identificando seu período de maior atuação neste litoral; foi possível verificar como as características das ondas estão se alterando conforme se aproximam da costa; e também observar o padrão das correntes atuantes no litoral; e a altura máxima das ondas que incidem sobre a região. E diante de comparações com boia e modelo, foi possível comprovar a eficiência da medição de ondas a partir de radar e do sistema WaMoS II para o litoral de Boa Viagem (Recife – PE).

Modificações nas posições médias dos centros de tempestades intensas assim como nos seus sentidos de propagação estão sendo sugeridas por diversos estudos sobre mudanças climáticas. Este fato pode ser determinante para a geração de ondas sobre os oceanos, e consequentemente para o conhecimento das climatologias de ondas. Na costa brasileira a falta de observações diretas em escala climática justifica o uso de técnicas de modelagem numérica para representação do fenômeno. Este trabalho apresenta resultados de simulações numéricas para caracterizar a climatologia das ondas de superfície e suas correspondentes perspectivas de mudanças para um futuro próximo sobre a região do Atlântico Sudoeste. Uma estratégia complexa de modelagem de ondas global, para assegurar a propagação de swell, e uma grade regional forçada por um ventos superficiais obtidos com um modelo de meso-escala atmosférico foi desenvolvida neste estudo. Os modelos utilizados foram o WAVEWATCH-III e o BRAMS. O período de 1982-1999 foi escolhido para representação do século XX com campos atmosféricos provenientes da REANÁLISE-I do NCEP, os quais são utilizados como controle do experimento. O período de 2030-2049 é investigado com base em dois cenários de projeções futuras CCSM3. Os valores médios de altura significativa para a porção Sudoeste do Atlântico Sul são superestimados no conjunto de simulação histórica do CCSM3; ao se considerar dois pontos de localização sobre a Bacia de Campos e Bacia de Santos, valores máximos do ciclo anual são encontrados durante os meses de outono enquanto que o conjunto referência apresenta valores máximos durante os meses de inverno. O estabelecimento de probabilidades de ocorrência de swell e wind sea revelam que o conjunto CCSM3 superestima a influência de swell gerados remotamente. Em termos das projeções climáticas para as bacias de Campos e Santos, pequenas diferenças nos valores médios de altura significativas aparecem de Maio a Dezembro, quando os resultados sugerem um leve aumento das alturas de ondas para as duas bacias quando comparadas com as respectivas médias do século XX. Por outro lado, a obtenção de séries de tendências durante os anos de 2030-2049 demonstram um padrão variável mas um fato comum aparece nos dois cenários de projeções climáticas: diminuição das alturas de ondas na área de oceano aberto e numa porção da região costeira próxima aos 20S, enquanto a porção sudoeste da região de estudo apresenta um pequeno aumento. Isto não é um desenvolvimento monotônico pois variabilidades interanuais de decadais estão evidentes para os dois cenários com diferentes amplitudes e fases entre elas. / Modifications in the mean position of the storm tracks as well as in the direction of propagation of severe storms have been suggested by many studies about climate change. This fact can be determined for the wind-wave generation over the oceans, and consequently for the wave climatology knowledge. In the coast of Brazil, the lack of long term direct observations of wave characteristics leads to the use of numerical modeling techniques to represent the phenomena. This study presents analysis of numerical simulations to characterize the climatology of surface gravity waves and the determined perspectives of changing in the near future for the Western South Atlantic region, with focus on its southern portion, off the southern Brazil coast. A complex strategy of global wave modeling to represent swell propagation associated with regional wave modeling forced by mesoscale winds is adopted; the models employed are WAVEWATCH-III and BRAMS. The period 1982-1999 is used to represent the 20th century with atmospheric fields from NCEP/Reanalysis-I, which results are used as reference. The period 2030-2049 is investigated based on two projected scenarios of the coupled climate model CCSM3. The average significant wave height for the Western South Atlantic is overestimated by the historical run of CCSM3; when considering two locations of interest, Campos and Santos Basins, the maximum values of the annual cycle are found during the autumn, while the reference field presents maximum values during the late winter. The evaluation of probabilities of occurrences of swell and wind sea revealed that CCSM3 overestimated the influence of remotely generated swell for the Western South Atlantic region. In terms of projected scenarios for Campos Basin and Santos Basin, some small differences in the average significant wave height appear from May to December, when the results suggest a small increase of wave height in both locations compared to the correspondent 20th century results. On the other hand, the obtained spatial distribution of trends during the period 2030-2049 shows a variable pattern, but a common feature appears in both projected scenarios of CCSM3: decrease of the wave heights in the open ocean area and part of the shelf around 20ºS, while the southwestern portion of the study region presents a small increase. This is not a monotonic behavior, because interannual and decadal variability are evident in both scenarios, with different amplitudes and phases between them.

The swell waves which are an important component of wind generated waves have significant effects on small craft and fisheries. The swell wave climate has an important role in the design and operation of fishing harbors and harbors for small craft. Despite this fact the swell wave climate is not well known for the Turkish coasts. The purpose of the present study was to identify the swell wave climate along the Black Sea coastline of T&uuml / rkiye. For this purpose wind and swell wave data for a 65 months period is obtained from ECMWF for the analysis. And the data are analyzed for thirteen locations selected along the Turkish coast. For every location the wind and swell wave roses, significant swell wave height versus Mean period of primary swell relations, extreme probability distribution and log-linear cumulative probability distribution are presented. Also some extreme swell events in the Black Sea occurred in the data period are presented for a better understanding of generation and propagation of swell waves. The results showed that the swell wave activity and severity is higher in the western Black Sea coastline of T&uuml / rkiye. The investigation of extreme swell events provided that the swell waves occur and diminish in a relatively short duration and the data available from ECMWF which is provided for 12 hour intervals is not sensitive to time enough for the investigation of swell wave occurrence and propagation. The significant swell wave height versus Mean period of primary swell relations and analysis on period of swell waves showed that the swell wave periods could reach up to 11 seconds in the Northern shores of T&uuml / rkiye.

Modificações nas posições médias dos centros de tempestades intensas assim como nos seus sentidos de propagação estão sendo sugeridas por diversos estudos sobre mudanças climáticas. Este fato pode ser determinante para a geração de ondas sobre os oceanos, e consequentemente para o conhecimento das climatologias de ondas. Na costa brasileira a falta de observações diretas em escala climática justifica o uso de técnicas de modelagem numérica para representação do fenômeno. Este trabalho apresenta resultados de simulações numéricas para caracterizar a climatologia das ondas de superfície e suas correspondentes perspectivas de mudanças para um futuro próximo sobre a região do Atlântico Sudoeste. Uma estratégia complexa de modelagem de ondas global, para assegurar a propagação de swell, e uma grade regional forçada por um ventos superficiais obtidos com um modelo de meso-escala atmosférico foi desenvolvida neste estudo. Os modelos utilizados foram o WAVEWATCH-III e o BRAMS. O período de 1982-1999 foi escolhido para representação do século XX com campos atmosféricos provenientes da REANÁLISE-I do NCEP, os quais são utilizados como controle do experimento. O período de 2030-2049 é investigado com base em dois cenários de projeções futuras CCSM3. Os valores médios de altura significativa para a porção Sudoeste do Atlântico Sul são superestimados no conjunto de simulação histórica do CCSM3; ao se considerar dois pontos de localização sobre a Bacia de Campos e Bacia de Santos, valores máximos do ciclo anual são encontrados durante os meses de outono enquanto que o conjunto referência apresenta valores máximos durante os meses de inverno. O estabelecimento de probabilidades de ocorrência de swell e wind sea revelam que o conjunto CCSM3 superestima a influência de swell gerados remotamente. Em termos das projeções climáticas para as bacias de Campos e Santos, pequenas diferenças nos valores médios de altura significativas aparecem de Maio a Dezembro, quando os resultados sugerem um leve aumento das alturas de ondas para as duas bacias quando comparadas com as respectivas médias do século XX. Por outro lado, a obtenção de séries de tendências durante os anos de 2030-2049 demonstram um padrão variável mas um fato comum aparece nos dois cenários de projeções climáticas: diminuição das alturas de ondas na área de oceano aberto e numa porção da região costeira próxima aos 20S, enquanto a porção sudoeste da região de estudo apresenta um pequeno aumento. Isto não é um desenvolvimento monotônico pois variabilidades interanuais de decadais estão evidentes para os dois cenários com diferentes amplitudes e fases entre elas. / Modifications in the mean position of the storm tracks as well as in the direction of propagation of severe storms have been suggested by many studies about climate change. This fact can be determined for the wind-wave generation over the oceans, and consequently for the wave climatology knowledge. In the coast of Brazil, the lack of long term direct observations of wave characteristics leads to the use of numerical modeling techniques to represent the phenomena. This study presents analysis of numerical simulations to characterize the climatology of surface gravity waves and the determined perspectives of changing in the near future for the Western South Atlantic region, with focus on its southern portion, off the southern Brazil coast. A complex strategy of global wave modeling to represent swell propagation associated with regional wave modeling forced by mesoscale winds is adopted; the models employed are WAVEWATCH-III and BRAMS. The period 1982-1999 is used to represent the 20th century with atmospheric fields from NCEP/Reanalysis-I, which results are used as reference. The period 2030-2049 is investigated based on two projected scenarios of the coupled climate model CCSM3. The average significant wave height for the Western South Atlantic is overestimated by the historical run of CCSM3; when considering two locations of interest, Campos and Santos Basins, the maximum values of the annual cycle are found during the autumn, while the reference field presents maximum values during the late winter. The evaluation of probabilities of occurrences of swell and wind sea revealed that CCSM3 overestimated the influence of remotely generated swell for the Western South Atlantic region. In terms of projected scenarios for Campos Basin and Santos Basin, some small differences in the average significant wave height appear from May to December, when the results suggest a small increase of wave height in both locations compared to the correspondent 20th century results. On the other hand, the obtained spatial distribution of trends during the period 2030-2049 shows a variable pattern, but a common feature appears in both projected scenarios of CCSM3: decrease of the wave heights in the open ocean area and part of the shelf around 20ºS, while the southwestern portion of the study region presents a small increase. This is not a monotonic behavior, because interannual and decadal variability are evident in both scenarios, with different amplitudes and phases between them.