The various aspects of the 3D cellular confinement systems (geocells) subjected to static loading are comprehensively studied with the help of experimental and numerical studies. The performances of the geocells were separately studied in both sand and clay beds. Laboratory tests were performed on single as well as multiple cells. The behavior of 3D-cells made of different materials such as Novel polymeric alloy, geogrids and bamboo were compared. Moreover, the performances of the geocells were compared with other forms of geosynthetic reinforcements namely, geogrids and the combination of geocells and geogrids. In addition to comprehensive experimental study, 2-dimensional and 3-dimensional numerical modelling efforts are also presented. A Realistic approach of modelling the geocells in 3D framework has been proposed; which considers the actual curvature of the geocell pockets. An Analytical equation has been proposed to estimate the increase in the bearing capacity of the geocell reinforced soft clay beds. Similarly, a set of equations to estimate the stress and strains on the surface of the geocells subjected to compressive loading were also proposed. A case study highlighting the innovative use of the geocell foundation to support the embankment on soft settled red mud has been documented in the thesis. A new and emerging application of geocell to protect underground utilities and the buried pipelines has been proposed. At the end, behavior of the geocell under cyclic loading has also been discussed. Firstly, laboratory model tests were performed to understand the behavior of the geocells in sand and clay beds. Test results of unreinforced, geogrid reinforced, geocell reinforced, and geocell reinforced with additional planar geogrid at the base of the geocell cases were compared separately for sand and clay beds. Results revealed that the use of geocells increases the ultimate bearing capacity of the sand bed by 2.9 times and clay bed by 3.6 times. Provision of the basal geogrid increases the ultimate load carrying capacity of the sand and clay bed by about 3.6 times and 4.9 times, respectively. Besides increasing the load carrying capacity, provision of the planar geogrid at the base of the cellular mattress arrests the surface heaving and prevents the rotational failure of the footing. Geocells contribute to the load carrying capacity of the foundation bed, even at very low settlements. In addition, the effect of infill materials on the performance of the geocell was also studied. Three different infill materials, namely aggregate, sand and local red soil were used in the study. Results suggest that the performance of the geocell was not heavily influenced by the infill materials. Out of which aggregate found to be slightly better than other two infill materials. Further, 2-dimensional numerical studies using FLAC2D (Fast Lagrangian Analysis of Continua in 2D) were carried out to validate the experimental findings. The equivalent composite approach was used to model the geocells in 2-dimensional framework. The results obtained from the FLAC2D were in good agreement with the experimental results. However, in the sand bed, FLAC2D overestimated the bearing pressure by 15% to 20% at higher settlements. In addition, the joint strength and the wall deformation characteristics of the geocells were studied at the single cell level. The study helps to understand the causes for the failure of the single cell in a cellular confinement system. Experimental studies were conducted on single cells with cell pockets filled up with three different infill materials, namely, silty clay, sand and the aggregates. The results of the experimental study revealed that the deformation of the geocell wall decreases with the increase in the friction angle of the infill material. Measured strain values were found to be in the range of 0.64% to 1.34% for different infill materials corresponding to the maximum applied bearing pressure of 290 kPa. Experimental results were also validated using FLAC3D. Findings from the numerical studies were in accordance with the experimental results. A simple analytical model based on the theory of thin cylinders was also proposed to calculate the accumulated strain of the geocell wall. This model operates under a simple elastic solution framework. The proposed model slightly overestimates the strains as compared to experimental and numerical values. A realistic approach of modelling the geocells in 3-dimensional (3D) framework has been proposed. Numerical simulations have been carried out by forming the actual 3D honeycomb shape of the geocells using the finite difference package FLAC3D. Geocells were modeled using the geogrid structural element available in the FLAC 3D with the inclusion of the interface element. Geocells, foundation soil and the infill soil were modeled with the different material model to match the real case scenario. The Mohr Colombo model was used to simulate the behavior of the sand bed while modified Cam clay was used to simulate the behavior of the clay bed. It was found that the geocells distribute the load in lateral direction to a relatively shallow depth as compared to unreinforced case. More than 50% reduction in the stress in the presence of geocells and more than 70% reduction in the stress in the presence geocells with basal geogrid were observed in sand and clay beds. The numerical model was also validated with the experimental studies and the results were found to be in good agreement with each other. The validated numerical model was used to study the influence of various properties of the geocells on the performance of the reinforced foundation beds. The performance of the foundation bed was directly influenced by the modulus and the height of the geocells. Similarly, the pocket size of the geocell inversely affected the performance of the reinforced beds. The geocell with textured surface yielded better performance than the geocell with smooth surface. A case history of the construction of a 3 m high embankment on the geocell foundation over the soft settled red mud has been documented. Red mud is a waste product from the Bayer process of Aluminium industry. The reported embankment is located in Lanjigharh (Orissa) in India. The geotechnical problems of the site, the design of the geocell foundation based on experimental investigation and the construction sequences of the geocell foundations in the field are discussed. Based on the experimental studies, an analytical model was also developed to estimate the load carrying capacity of the soft clay bed reinforced with geocell and the combination of geocell and geogrid. The solution was established by superimposing the three mechanisms viz. lateral resistance effect, vertical stress dispersion effect and the membrane effect. By knowing the pressure applied on the geocell, tensile strength of the geogrid and the limiting settlement, the increment in the load carrying capacity can be calculated. The analytical model was validated with the experimental results and the results were found to be in good agreement with each other. The results of the experimental and analytical studies revealed that the use of the combination of geocell and the geogrid is always beneficial than using the geocell alone. Hence, the combination of geocell and geogrid was recommended to stabilize the embankment base in Lanjigharh. Over 15,000 mof embankment base was stabilized using geocell foundation. The foundation work was completed within 15 days using locally available labors and the equipment. Construction of the embankment on the geocell foundation has already been completed. The constructed embankment has already sustained two monsoon rains without any cracks and seepage. Like Aluminum tailings (redmud), geocell foundations can also be used in various other mine tailings like zinc, copper etc. Geocell foundation can offer potential solutions to storage problems faced by various mining industries. The thesis also proposes a potential alternative to the geocells in the form of bamboocells in order to suit the Indian scenario. Indian has the 2nd largest source of bamboo in the world. The areas particularly rich in bamboo are the North Eastern States, the Western Ghats, Chattisgarh and Andaman Nicobar Islands. The tensile strength and surface roughness of the bamboo was found to be 9 times and 3 times higher than geocell materials. In order to use the bamboo effectively, 3D cells (similar to geocells) and 2D grids (similar to geogrids) are formed using bamboo known as bamboocells and bamboogrids respectively. The idea behind forming bamboocells is to extract the additional confining effect on the encapsulated soil by virtue of its 3-dimensional shape. The laboratory investigations were performed on a clay bed reinforced with natural (bamboo) and commercial (geosynthetics) reinforcement materials. The performance of bamboocells and bamboogrids reinforced clay beds were compared with the clay bed reinforced with geocells and geogrids. The ultimate bearing capacity of the bamboocell and bamboogrid reinforced clay bed was found to be 1.3 times that of reinforced with geocell and geogrid. The settlement of the clay bed was reduced by 97% due to the insertion of the combination of the bamboocell and bamboogrid as compared to the unreinforced clay bed. The bamboo was treated chemically to increase the durability. The performance of the bamboo was reduced by 15-20% after the chemical treatment; still the performance was better than its geosynthetic counterparts. Analytical studies revealed that the 3% of the ultimate tensile strength of the bamboogrid was mobilized while resisting the footing load. The study also explored the new and innovative applications of the geocells to protect underground utilities and buried pipelines. The laboratory model tests and the numerical studies were performed on small diameter PVC pipes, buried in geocell reinforced sand beds. In addition to geocells, the efficacy of only geogrid and geocell with additional basal geogrid cases were also studied. A PVC (Poly Vinyl Chloride) pipe with external diameter 75 mm and thickness 1.4 mm was used in the experiments. The vehicle tire contact pressure was simulated by applying the pressure on the top of the bed with the help of a steel plate. Results suggest that the use of geocells with additional basal geogrid considerably reduces the deformation of the pipe as compared to other types of reinforcements. Further, the depth of placement of pipe was also varied between 1B to 2B (B is the width of loading plate) below the plate in the presence of geocell with additional basal geogrid. More than 50% reduction in the pressure and more than 40% reduction in the strain values were observed in the presence of reinforcements at different depths as compared to the unreinforced beds. Further, experimental results were validated with 3-dimensional numerical studies using 3D FLAC. Good agreement in the measured pipe stain values were observed between the experimental and numerical studies. In addition, the results of the 1-g model tests were scaled up to the prototype case of the shallow buried pipeline below the pavement using the appropriate scaling laws. The efficacy of the geocells was also studied under the action of cyclic loading. The laboratory cyclic plate load tests were performed in soft clay bed by considering the three different cases, namely, unreinforced, geocell reinforced and geocell with additional basal geogrid reinforced. The coefficient of elastic uniform compression (Cu) was evaluated from the cyclic plate load tests for the different cases. The Cu value was found to increase in the presence of geocell reinforcement. The maximum increase in the Cu value was obtained for the case of the clay bed reinforced with the combination of geocell and the geogrid. The results of the laboratory model tests were extrapolated to prototype foundation supporting the low frequency reciprocating machine. The results revealed that, in the presence of the combination of geocell and the geogrid the natural frequency of the foundation-soil system increases by 4 times and the amplitude of the vibration reduces by 92%.

This study investigates the lithological characteristics, and lateral and vertical facies trends of poorly understood, deep-marine matrix-rich sedimentary rocks. Two laterally extensive, well-exposed outcrops of slope and proximal basin floor deposits were investigated from the Neoproterozoic Windermere Supergroup. Significantly, matrix-rich beds have been found to undergo the same lateral trends (over ~200-650 m) in both outcrops. Initially, thicker, clayey sandstone transitions laterally to a bipartite bed with the development of an upper, planar-based, more matrix-rich unit. Further laterally, the basal unit progressively thins until it pinches out, and all that remains is the upper, more matrix-rich unit – a sandy claystone. It too thins and then pinches out. Draping the entire transect is a thin, matrix-poor structured unit overlain by a mudstone or claystone cap. These trends are interpreted to reflect a progressive but rapid lateral evolution of flow structure controlled primarily by particle settling, namely sand, from mud-rich avulsion-related flows.

Macroalgas têm sido descritas no Brasil desde a região entremarés até cerca de 120 metros de profundidade na plataforma continental. O objetivo deste trabalho foi a caracterização da flora marinha bêntica em bancos de rodolitos entre 20-30 metros de profundidade, do infralitoral sul do estado do Espírito Santo. Os métodos utilizados neste projeto incluíram a coleta meticulosa de material através de mergulho autônomo, que preserva o material mais frágil em contraste com a utilização de dragagem. Estudos no infralitoral do estado do Espírito Santo são muito escassos. Esta flora é conhecida principalmente pela análise de material arribado nas praias e proveniente de algumas dragagens e mergulhos. Este trabalho procura contribuir para o inventário da flora de algas marinhas brasileiras, assim como contribuir para o conhecimento da biodiversidade de macroalgas enfocando especialmente a flora do infralitoral através de um estudo sistemático, descrevendo e ilustrando os aspectos mais importantes das espécies encontradas. Foram identificados 138 táxons de algas marinhas, sendo 77,5% (107 táxons) representantes do Filo Rhodophyta, 11,6% (16 táxons) representantes do Filo Chlorophyta e 10,9% (15 táxons) representantes da Classe Phaeophyceae. Observou-se também que a riqueza de espécies de macroalgas no inverno decresce acentuadamente em relação ao período de verão. Esta redução na riqueza de espécies pode ser explicada pela instabilidade gerada nos bancos de rodolitos no período de inverno, pela maior frequência de tempestades. Dois gêneros são referidos pela primeira vez para o Atlântico ocidental, Tsengia K. C.Fan & Y.P. Fan (Halymeniales/Rhodophyta) e Pugetia Kylin (Gigartinales/Rhodophyta). Foram registradas duas novas ocorrências para a flora marinha brasileira, Erythrocladia endophloea M.A. Howe e uma espécie ainda não identificada de Pseudobryopsis Berthold. Dezesseis novas ocorrências foram registradas para o estado do Espírito Santo: Acrochaetium liagorae Børgesen, Anotrichium yagii (Okamura) Baldock, Caulerpa brachypus Harvey, Ceramium affine Setchell & N.L.Gardner, Chondria dasyphylla (Woodward) C. Agardh, Dasya caraibica M.A. Howe, Dasya rigidula (Kützing) Ardissone, Derbesia vaucheriaeformis (Harvey) J. Agardh, Erythrocladia pinnata W.R. Taylor, Gracilaria blodgettii Harvey, Griffithsia globulifera Harvey ex Kützing, Nitophyllum cf. punctatum (Stackhouse) Greville, Rhipiliopsis stri (S. Earle & J.R. Young) Farghaly & Denizot, Streblonema invisibile Hoyt, Udotea unistratea D.S. Littler & M.M. Littler e Yuzurua poiteaui (J.V. Lamouroux) Martin-Lescanne var. gemmifera (Harvey) Sentíes, M.T. Fujii & Díaz-Larrea. Para Platoma cyclocolpum (Montagne) F. Schmitz, Platoma sp. e Dudresnaya sp., espécies de rara ocorrência na costa brasileira, são fornecidas informações sobre estruturas reprodutivas e estádios de pós-fertilização. Estas novas adições na flora indicam a importância da realização de pesquisas em áreas pouco estudadas da costa brasileira. O infralitoral ainda representa uma lacuna no conhecimento das algas e outros organismos marinhos. Estudos que utilizam mergulho autônomo geralmente fornecem novidades para a comunidade científica, principalmente no que diz respeito às espécies frágeis que não resistem aos métodos de dragagem. / In Brazil, macroalgae have been reported from the intertidal to about 120 meters depth on the continental shelf. The aim of this study was to characterize the marine benthic flora in banks of rhodoliths between 20-30 meters depth, in the subtidal zone of southern Espirito Santo state. The methods utilized in this project included a careful collection of material through SCUBA diving, which preserves the more fragile material in contrast to the use of dredging. Studies on the sublittoral flora of the state of Espirito Santo are very scarce. This flora has been studied mainly through material casted ashore on the beaches and through some material from dredging and diving. This study seeks to contribute to the inventory of the Brazilian marine algae flora and also contribute to the knowledge of the biodiversity of the algae, focusing on sublittoral flora, by a systematic study, through descriptions and illustrations of the most important characteristics of sampled species. This research resulted in the identification of 138 taxons of marine algae being 77,5% (107 taxons) Rhodophyta, 11,6% (16 taxons) Chlorophyta and 10,9% (15 taxons) Phaeophyceae. It was also observed that macroalgae species richness decreases sharply during winter season, in comparison to summer period. This reduction in species richness could be attributed to the instability generated in the rhodoliths banks during winter, by the increasing of storm conditions. In this work we recorded two new genera for the tropical Western Atlantic, Tsengia K. C.Fan & Y.P. Fan (Halymeniales/Rhodophyta) and Pugetia Kylin (Gigartinales/Rhodophyta), and two new records for the Brazilian marine flora: Erythrocladia endophloea M.A. Howe and a species of Pseudobryopsis Berthold not yet identified. Sixteen new occurences were also registered for the state of Espírito Santo: Acrochaetium liagorae Børgesen, Anotrichium yagii (Okamura) Baldock, Caulerpa brachypus Harvey, Ceramium affine Setchell & N.L.Gardner, Chondria dasyphylla (Woodward) C. Agardh, Dasya caraibica M.A. Howe, Dasya rigidula (Kützing) Ardissone, Derbesia vaucheriaeformis (Harvey) J. Agardh, Erythrocladia pinnata W.R. Taylor, Gracilaria blodgettii Harvey, Griffithsia globulifera Harvey ex Kützing, Nitophyllum cf. punctatum(Stackhouse) Greville, Rhipiliopsis stri (S. Earle & J.R. Young) Farghaly & Denizot, Streblonema invisibile Hoyt, Udotea unistratea D.S. Littler & M.M. Littler and Yuzurua poiteaui (J.V. Lamouroux) Martin-Lescanne var. gemmifera (Harvey) Sentíes, M.T. Fujii & Díaz-Larrea. There were provided informations about reproductive structures and stages of postfertilization from Platoma cyclocolpum (Montagne) F. Schmitz, Platoma sp. and Dudresnaya sp., species that occur rarely in Brazilian coast. These new additions to the flora indicate the importance of conducting research in less studied areas of the Brazilian coast. The subtidal zone still represents a gap in the knowledge of the algae and other marine organisms. Studies using SCUBA diving often yields new references especially regarding fragile species that can not resist to the dredging method.

Abstract embargoed until 2030-11-11

The ozone decomposition reaction was performed in a 2.5cmx40cmx450cm two dimensional (2D) catalytic fluidized bed reactor. Commercial FCC catalyst impregnated with Fe2O3 was used at superficial gas velocities ranging between 0.006 m/s and 0.55 m/s. The onset velocity of the turbulent regime (uc) was determined as 0.4 m/s. The catalyst activity was optimized so that the effect of inter-phase mass transfer could be accentuated in the conversion reading. It was found that the general bubbling-turbulent model of Thompson et. al. (1999) combined with the mass transfer correlations of Kunii and Levenspiel (1991), Foka et. al. (1996) and Miyauchi et. al. (1980)gave reasonable predictions of the experimental data. The gradual improvement of reactor performance with an increase in superficial velocity (as predicted by the Thompson et. al. model) was not observed; instead a discontinuity of the reactor performance was noted in the vicinity of uc. More experimental work is required to substantiate this observation. Copyright / Dissertation (MEng)--University of Pretoria, 2009. / Chemical Engineering / unrestricted

Millions of Americans engage in tanning each year, defined as intentional ultraviolet radiation (UVR) exposure in the form of sunbathing or the use of indoor tanning beds. An emerging body of research suggests that UVR has addictive properties and some tanners engage in excessive tanning. This article provides an overview of the evidence of tanning addiction and a systematic review of existing tanning interventions with the goal of evaluating their potential to impact addicted tanners. Our search identified 24 intervention studies that were summarized and discussed according to 3 primary themes. First, there is a dearth of tanning interventions that target excessive tanning or are designed as treatments for tanning addiction. Second, tanning interventions are primarily educational interventions designed to increase knowledge of the risks of tanning. Third, there are notable aspects of existing tanning interventions that are relevant to addiction science, including the use of brief motivational and cognitive-behavioral-based interventions. Future directions are considered including recommendations for utilizing the existing evidence base to formulate interventions targeting excessive tanners.

In situ planetary effective thermal conductivity measurements are typically made using a long needle-like probe, which measures effective thermal conductivity in the probe‟s radial (horizontal) direction. The desired effective vertical thermal conductivity for heat flow calculations is assumed to be the same as the measured effective horizontal thermal conductivity. However, it is known that effective thermal conductivity increases with increasing compressive pressure on granular beds and horizontal stress in a granular bed under gravity is related to the vertical stress through Jaky‟s at-rest earth pressure coefficient. No research has been performed previously on determining the anisotropic effective thermal conductivity of dry granular beds under compressive uniaxial pressure. The objectives of this study were to examine the validity of the isotropic property assumption and to develop a fundamental understanding of the effective thermal conductivity of a dry, noncohesive granular bed under uniaxial compression. Two experiments were developed to simultaneously measure the effective vertical and horizontal thermal conductivities of particle beds. One measured effective thermal conductivities in an atmosphere of air. The second measured effective thermal conductivities in a vacuum environment. Measurements were made as compressive vertical pressure was increased to show the relationship between increasing pressure and effective vertical and horizontal thermal conductivity. The results of this experiment show quantitatively the conductivity anisotropy for different materials. Based on the effective thermal conductivity models in the literature and results of the two experiments, a simple model was derived to predict the increase in effective vertical and horizontal thermal conductivity with increasing compressive vertical applied pressure of a granular bed immersed in a static fluid. In order to gain a greater understanding of the anisotropic phenomenon, finite element simulations were performed for a vacuum environment. Based on the results of the finite element simulations, the simple derived model was modified to better approximate a vacuum environment. The experimental results from the two experiments performed in this study were used to validate both the initial simple model and the modified model. The experimental results also showed the effects of mechanical properties and size on the anisotropic effective thermal conductivity of granular beds. This study showed for the first time that compressive pressure-dependent effective thermal conductivity of granular beds is an anisotropic property. Conduction through the fluid has been shown to have the largest contribution to the effective thermal conductivity of a granular bed immersed in a static fluid. Thermal contact resistance has been shown to have the largest influence on anisotropic effective thermal conductivity of a granular bed in a vacuum environment. Finally, a discussion of future work has been included.

<p> Sedimentary structures, textures and fabric were studied in detail in eight turbidite greywacke beds from the Cloridorme Formation (Middle Ordovician), Gaspe, Quebec. The beds are exposed on the wave-cut platform near Grande Vallee and were traced for about two miles along the strike (276 degrees), which is parallel to the average current direction (274 degrees) as indicated by sole mark directions. </p> <p> The beds under study show the following systematic downcurrent changes along the strike from east to west: (i) Sole mark types show the following changes: (1) tool marks such as grooves, prod marks and isolated flute marks, to (2) longitudinal ridges, longitudinal ridges with overlapping flute, closely spaced flutes, to (3) poorly developed, shallow longitudinal ridges with occasional cuspate crossing bars, to (4) smooth bottom with occasional grooves. (ii) There is an increase in variance of sole mark directions without a large change in the mean direction in most beds, but the sole mark direction changes by nearly 90° as one of the beds is traced from east to west along the strike. (iii) Most of the beds are massive and are divided into two parts by a bedding joint. However, in the proximal region, if a bed is unusually thin, the bedding joint is absent and the bed shows slightly wavy, plane-laminated structure at places. (iv) Grain orientations are generally statistically non-significant in the upper massive part of the bed in the proximal region and significant in the rest of the bed. Significant grain orientations and graptolite orientations show large deviations from the sole in the distal region. Deviations increase towards the top of the bed. (v) The beds show a change from good grading to poor grading or slight reverse grading from the proximal to distal region. It is considered that the beds were deposited by low concentration, highly turbulent currents. Deposition of the beds took place in two distinct phases. First a 'quick' bed separated from the current was sheared extensively by the overflowing current and on consolidation formed the lower part of the bed. Later deposition in the proximal region from the upper part of the current and the part close to the tail was by settling of individual particles from the suspension. Separation and consolidation of another 'quick' bed in some cases formed the upper part of the beds in the distal region. </p> <p> The depositing currents produced a good vertical and lateral grain size grading in the proximal region, but poor vertical grading in the distal region due to the loss of coarse grains and possibly increased concentration of flocculated clay. Also, the turbidity currents tended to "meander" greatly on slowing down in the distal region. </p> / Thesis / Doctor of Philosophy (PhD)

<p> An Experimental investigation has been conducted to determine the effects on degree of reduction and efficiency of utilization of gases of changes in the levels of several variables when reducing fixed beds of commercial hematite pellets. The effects on reduction behaviour of changes in the levels of reducing gas composition and flow rate, and reaction temperature, were determined by graphical and numerical techniques.</p> / Thesis / Master of Engineering (MEngr)

Community gardens are places where people gather to share the experience of gardening. However, users often struggle to find time in their busy schedules to care for their plots and crops. This research explores the impact of different watering systems on gardening based on plant quality, cost, labor, and time for. The study analyzed the inputs and outputs of hand watering, automated, and subsurface irrigation treatments in hopes of identifying how to design community gardens for the most efficient application of water, ultimately striving to increase crop production, crop quality, and community interest. Results indicate that subsurface irrigation systems are more likely to save time, reduce water use, and produce a higher quality crop when application and setting is adequate.