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.

Expansive or swelling soils, exist in many part of the world, show excessive volume changes with increasing water content. As a result of this volume increase, expansive soils apply vertical and lateral pressures to the structures located or buried in these regions. Many researchs have been carried out on vertical swelling pressures helping to the engineers to design structures withstanding on these stresses. However, lateral swell behaviour of swelling soils have not been fully understood yet. Structures such as / basement walls, water tanks, canals, tunnels, underground conduits and swimming pools which will be built in expansive soils have to be designed to overcome the lateral swelling pressures as well as the other lateral pressures exerted by the soil. For this aim accurate and reliable methods are needed to predict the magnitude of lateral swelling pressures of expansive soils and to understand the lateral swelling behaviour of expansive soils. In this experimental study, the lateral swelling behaviour of an highly expansive clay is investigated using a modified thin wall oedometer which was developed in the METU Civil Engineering Department Soil Mechanics Laboratory earlier. Statically compacted samples were used in constant volume swell (CVS) tests to measure the magnitude of the lateral and vertical swelling pressures. To study the relationship between the lateral and vertical sweeling pressures, they were measured simultaneously. The samples having different initial water contents and different initial dry densities were used to study the effects of these variables on the vertical and the lateral swelling pressures. It is observed that both lateral and vertical pressures increases with increasing initial dry density and they decrease with increasing initial water content. Swell pressure ratio, the ratio of lateral swelling pressure to the vertical one, is increasing with increasing initial water content. Time needed to obtain the magnitude of maximum lateral and vertical pressures decreases with increasing initial water content and increases with increasing initial dry density.

Lime stabilisation is a ground improvement technique used to improve the engineering properties of cohesive fill materials. During earthworks operations, specialist plant is used to rotovate the clay fill material and intermix lime binder around clay clods. After completion of the lime treatment, the layer is compacted in the usual way. Immediately after mixing, the lime instigate a series of physico-chemical reactions within the clay soil. Where the chemical reactions are favourable and with time after compaction (curing) the material becomes progressively stronger and durable to environmental influences, e.g. inundation by surface or ground water. However, where sulphate is present within the soil, the reactions may change and the ingress of water into the layer can result in the expansive growth of deleterious minerals e.g. ettringite. While sulphate swell issues are relatively rare, when they do occur the degree of expansion can be very high. A high profile sulphate swell failure developed during the construction of the M40, Oxford, UK in 1989. Over the winter period after the lime stabilisation works, a 250mm deep lime treated layer heaved by up to 150mm - destroying the overlying road construction. Since the M40 failure, a substantial amount of effort has been undertaken to better understand the sulphate swell reactions and in this regard the state of scientific knowledge is relatively strong. A fundamental issue for field applications of lime stabilisation is that the vast majority of research has been undertaken on laboratory specimens prepared using methods which do not reflect site practice. Laboratory studies often use oven dried and finely crushed clay, whereas site operations will treat much larger clay clods to result in a more heterogeneous distribution of lime through the compacted soil body. With large clay clods, the chemical reactants must migrate through clods and this may cause the sequence of chemical reactions to change. A further challenge is that laboratory studies are typically undertaken with cure temperatures of 20°C, whereas a typical near surface temperature in the UK is <10°C. This is of particular relevance to sulphate swell failures which are reported to coincide with a reduction in ambient temperature over winter periods. Thus, the direct relevance of laboratory studies to site application was unclear. A series of laboratory experiments using a preparation method which reflects field applications of lime stabilisation was used to investigate the influence of large clay clods on the durability of lime stabilised clay soil. This method was applied to both low and high sulphate clay soils. A fundamental discovery from work on low sulphate clay is that the addition of lime binder to the surface of the clay clods causes a physico-chemical boundary to form. This boundary develops due to the rapid increase to the plastic limit of the clay preventing adjacent clods from joining together during compaction. This causes the engineering properties of each individual clod to develop independent to its neighbours and for each clay clod to be separated by an inter-clod pore space. The strength of each individual clay clod will increase with curing as the added lime dissociates into Ca2+ and OH- and migrates to form C-S-H deep within the clods. Where the material is compacted wet of the optimum water content, this condition improves ion migration and enables development of diffuse cementation deep within clods. The inter-clod porosity remains as a weakness throughout curing especially during specimen soaking, where the pore channels comprise a pathway, accelerating the ingress of soaking water. With low sulphate soil, the soaking water softens the treated material, however, with high TPS soil substantial sulphate swelling may develop. Thus, efforts to minimise this porosity during preparation is important and the use of quicklime with longer mellowing periods can cause the clay clods to develop high strength before compaction. The high strength clods resist compaction and the degree of inter-clod porosity in the compacted mass increases, worsening specimen durability to water ingress. The investigations into high sulphate clays included the development of a Novel Swell Test (NST) to assess volume change. A unique aspect of the NST was that the sulphate swell response of the lime treated material was investigated at site realistic temperatures of 8°C. It was identified that, when compared with standard laboratory test temperatures of 20°C the rate of sulphate swell is substantially higher at the low temperature. The mineralogical testing has permitted the hypothesis that, at 8°C the growth of crystalline ettringite becomes slower and the ettringite precursor, which has a high affinity to imbibe water, remains in this state for much longer. Thus, laboratory swell tests at 20°C may substantially underestimate the degree of swell that may develop in the field. As a pressing need, it is recommended that the industry adapt sulphate swell test methods to appraise the degree of swell at field realistic temperatures i.e. < 10°C. The work also identifies that the primary defence against sulphate swell is to condition the fill so that the risk of post compaction water ingress, via inter-clod porosity, is minimised. The use of GGBS and water addition during extended mellowing periods also reduces the degree of sulphate swell in natural clay soils. This work concludes that working methods for lime stabilisation of medium high plasticity soils of a potentially high sulphate content, should be adapted to encourage diffuse cementation and minimise the degree of (post compaction) inter-clod porosity. Practically this involves the use of hydrated lime and the addition of mixing water throughout extended mellowing periods. Fundamentally, the study recommends that where construction programmes allow, the long term durability of a fill material should be the priority over immediate strength.

Freak waves suddenly strike the southwest of Taiwan, may cause damages of coastal structures, tourist facilities and endanger maritime navigation. The prediction of swells and large waves is under development. In order to improve out understanding of the characteristics of swells, this study analysis data collected from a nearshore weather bouy and a coastal wave station. The Wave Watch 3 model is applied with several wind fields, and compared results with that of AVISO. The results show that (1) Waters in southwest of Taiwan, in the northeast monsoon season, the peak wave spectral energy tends to sift from short period to longer period, whereas in the southwest monsoon season, the spectrum of energy varies rapidly and is stronger. During the passage of typhoons, swells from the southern tip of Taiwan show stronger energy in the early stage and weaken gradually, on the other hand, swells from the northern tip of Taiwan show increasing energy spectrum to a peak value. The wave energy diminished after typhoon passed Taiwan Strait. (2) The patterns of wave spectrum are related to the winds. A single peak pattern is usually caused by the local winds. A double peaks wave spectrum suggests both local wind and remote forcing. The lower frequency energy is due to swells. (3) In order to separate the swells from the wind waves in the case of double peaks wave spectrum, two methods are applied. For the no typhoon period, a modified ¡¥P-M spectrum¡¦ is useful as well as is the ¡¥derivative energy spectrum¡¦. For the typhoon period, only the later method provides reasonable results. (4) Based on the analysis of separated wave spectrum, the ratio of occurrence is 65% wind wave and 35% swell in the normal days. The ratio varies during typhoon period. (5) The comparisons of Wave Watch 3 model output with AVISO data suggest that the forcing of QSCAT/NCEP Blended wind provides a better result.

In investigating ocean surface waves at a location, it is often to describe the waves with spectrum. A wave spectrum measures the distribution of wave energy from the wave trains in all different directions and all different periods at a location. Since the waves at a location contain seas and swells (which are the waves generated by local and remote wind systems respectively), a wave spectrum is viewed composing of different portions of the seas and swell spectrum. How to precisely partition a wave spectrum for each wave system (seas and swells) is of practical need in engineering practice, wave forecast, and coastal water management. At present, there are many different partitioning schemes, but not all are reliable and feasible enough for operational use. This report presents a wave system partition scheme followed by an identification scheme, which uses TMA spectrum, to identify different wave systems. This partition and identification scheme is intended for operationally use in partitioning the swell and wind sea in spectrum at finite water depth. Automated spectral partition and identification have been developed to evaluate swell systems in data during typhoon Meari.

Problems associated with shrink-swell soils are well known geotechnical problems that have been studied and researched by many geotechnical researchers for many decades. Potentially shrink-swell soils can be found almost anywhere in the world especially in the semi-arid regions of the tropical and temperate climate. Foundation slabs on grade on shrink-swell soils are one of the most efficient and inexpensive solutions for this kind of problematic soil. It is commonly used in residential foundations or any light weight structure on shrink-swell soils. Many design methods have been established for this specific problem such as Building Research Advisory Board (BRAB), Wire Reinforcement Institute (WRI), Post- Tensioning Institute (PTI), and Australian Standards (AS 2870) design methods. This research investigates most of these methods, and then, proposes a moisture diffusion soil volume change model, a soil-weather interaction model, and a soil-structure interaction model. The proposed moisture diffusion soil volume change model starts with proposing a new laboratory test to determine the coefficient of unsaturated diffusivity for intact soils. Then, it introduces the development of a cracked soil diffusion factor, provides a chart for it, and explains a large scale laboratory test that verifies the proposed moisture diffusion soil volume change model. The proposed soil-weather interaction model uses the FAO 56-PM method to simulate a weightless cover performance for six cities in the US that suffer significantly from shallow foundation problems on shrink-swell soils due to seasonal weather variations. These simulations provide more accurate weather site-specific parameters such as the range of surface suction variations. The proposed weather-site specific parameters will be input parameters to the soil structure models. The proposed soil-structure interaction model uses Mitchell (1979) equations for moisture diffusion under covered soil to develop a new closed form solution for the soil mound shape under the foundation slab. Then, it presents a parametric study by carrying out several 2D finite elements plane strain simulations for plates resting on a semiinfinite elastic continuum and resting on different soil mounds. The parametric study outcomes are then presented in design charts that end with a new design procedure for foundation slabs on shrink-swell soils. Finally, based on the developed weather-soil-structure interaction models, this research details two procedures of a proposed new design method for foundation slabs on grade on shrink-swell soils: a suction based design procedure and a water content based design procedure.

Fine grained soils, in particular clays of high plasticity, are known to have very low values of hydraulic conductivity. This low permeability causes several problems related to vegetation growth and stormwater runoff. One way to improve the permeability of clay soils is by using coarse aggregates as a fill material. Recently, Expanded Shale has been widely applied as an amendment to improve drainage properties of clayey soils. However, limited effort has been made to quantify the effect of Expanded Shale on the hydraulic conductivity or on the volume change of fine grained soils. Specifically, the field and laboratory tests required to quantify the amounts of Expanded Shale to be mixed with clays to obtain desired hydraulic conductivity values have not been conducted. This paper presents the results of a series of laboratory fixed-wall permeameter tests conducted on naturally occurring clay deposits in the Austin area with different plasticity. The testing program comprised of clay samples with different quantities of Expanded Shale aggregates by volume, ranging between 0 and 50%, and compacted at two different compaction efforts (60% and 100% of the standard Proctor compaction effort). The laboratory test results indicate that the hydraulic conductivity of the three soils increases by at least an order of magnitude when the Expanded Shale is mixed in quantities between 25 to 30% by volume depending on the compaction effort. Expanded Shale amended samples also showed lower swelling potential with increasing amendment quantities. Moreover, when the clay with the higher plasticity was mixed with 25% Expanded Shale, the compression and recompression ratios decreased by 25% and 15% respectively. / text

Thesis (M.S.)--Brigham Young University. Dept. of Geology, 2007. / Includes bibliographical references (p. 41-44).

Made available in DSpace on 2014-06-11T19:25:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-11-24Bitstream added on 2014-06-13T20:53:20Z : No. of bitstreams: 1 matos_fc_me_arafcf.pdf: 1148382 bytes, checksum: acb5e1bbfbec2e34aa0311d72ae2a142 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Os polissacarídeos naturais vêm sendo extensamente usados no desenvolvimento de formas farmacêuticas sólidas para liberação prolongada de fármacos, fato demonstrado na literatura por inúmeros estudos de utilização de polissacarídeos como quitosana, pectina, sulfato de condroitina, ciclodextrinas, dextranas, inulina, amilose e galactomananas de goma de guar e de alfarroba. Neste trabalho, os polímeros de galactomananas de flamboyant (Delonix regia) e de Carolina (Adenanthera pavonina), que são vegetais pertencentes à família Leguminosae, foram estudados após serem reticuladas por reação com trimetafosfato de sódio, um agente reticulante adequado para o uso farmacêutico e alimentício e avaliou-se os diferentes graus de reticulação das gomas em função da variação do tempo de reação (30 min. a 4 horas) e da concentração de base no meio reacional( 2% e 4%). As técnicas analíticas empregadas mostraram-se úteis na avaliação do grau de reticulação das amostras, exceto a espectroscopia na região do infravermelho, que não permitiu estabelecer diferenças entre as estruturas obtidas com diferentes graus de reticulação. A técnica da reologia apresentou-se como uma ferramenta importante na análise dos polímeros. Através das análises de viscoelasticidade foi possível observar mudanças significativas no comportamento viscoelástico dos polímeros reticulados quando comparados aos polímeros não-reticulados, oriundos do flamboyant ou da carolina. Para todos os tempos de reticulação, o módulo G’ apresentou valores maiores para os polímeros reticulados em comparação aos polímeros não reticulados, para todos os tempos de reticulação. A análise do grau de intumescimento das partículas aliada à reologia mostrou ser útil para a caracterização dos polímeros, permitindo observar que os produtos reticulados de ambas as origens tiveram sua capacidade... / The natural polysaccharides have been extensively used in the development of solid dosage forms for sustained release of drugs, a fact demonstrated by countless studies in the literature about the use of polysaccharides such as chitosan, pectin, chondroitin sulphate, cyclodextrins, dextran, syrup, starch and gum galactomannans of guar and carob. In this work, the polymers of galactomannans of Flamboyant (Delonix regia) and Carolina (Adenanthera pavonina), which are plants belonging to the family Leguminosae, were studied after a cross-linked reaction with sodium trimetaphosphate, which is a cross-linked agent suitable for pharmaceutical and food use. Then, from this study, the different cross-linked degrees of gum depending on the variation of the reaction time (30 minutes to 4 hours) and the concentration of base in the middle reaction (2% and 4%) were analyzed. The analytical techniques employed have proved useful in assessing the cross-linked degree of the samples, except in the infrared spectroscopy, which failed to establish differences between the structures obtained with different degrees of cross-linkage action. The rheology technique presented itself as an important tool in the analysis of polymers. Through the viscoelasticity analysis it was possible to see significant changes in the viscoelastic behavior of cross-linked polymers when compared to non-cross-linked polymers, from the Flamboyant or the Carolina. For all times of reticulation, the module G had higher values for the cross-linked polymers when compared to non-cross-linked polymers, for all times of cross-linkage actions. The analysis of the degree of swelling of the particles combined with rheology has shown to be useful for the characterization of polymers, enabling the observation that the cross-linked products of both origins had their ability to absorb water increased significantly in relation to non-cross-linked... (Complete abstract click electronic access below)

We examined small-displacement faults in the Jurassic Entrada Sandstone adjacent to the Iron Wash Fault, central Utah east of the San Rafael Swell, in order to describe the nature and timing of past fluid movement and deformation in the Entrada Sandstone. Using field studies, microscopy, and X-ray diffraction analysis, we identified mineralized fractures and cementation features in association with deformation bands and fractures at the interface of the Earthy and Slick Rock Members of the Entrada Sandstone. Where the faults cross the Earthy-Slick Rock Member interface, deformation band faults in the Slick Rock Member become opening-mode fractures in the Earthy Member. These fractures are frequently mineralized with calcite, and goethite pseudomorphs after pyrite, providing evidence of at least two phases of fluid flow from the Entrada reservoir into the caprock in connection with deformation bands. We also observe mineralized fractures, poikilotopic cementation, and spherical to elongate concretions on and within deformation band fins in the Slick Rock Member. These features indicate the presence and movement of fluids parallel to and between deformation band fins. At some sites, deformation band faults and fractures cross and offset the interface; at others, they are present in both units, but deformation band faults do not cross the interface and fractures are not directly connected to any bands. Mineralized fractures are only found at breached-interface sites; evidence for fluid flow in the Slick Rock Member is only found in deformation band fins. Interface crossing and fracture formation is not related to proximity to the Iron Wash Fault. We propose that mesoscale faults can act as seal bypass systems and allow fluid leakage from reservoir rock into overlying less permeable rocks. Deformation bands act as both conduits for and barriers to flow, seen most clearly in deformation band fins where iron staining and mineralization is constrained between sets of bands within the fin. In CO2 or wastewater injection scenarios, interface deformation may prevent successful fluid trapping and cause re-emission of injected fluids.