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.

Thesis (Ph. D.)--Flinders University, 2006. / Title from PDF t.p. (viewed on Mar. 11, 2007). Includes bibliographical references.

The modeling of Sand Asphalt and experiments to measure their rheological properties are of vital concern to many industrial processes especially highway and roadway pavement construction industry. A variety of hot mix asphalt mixtures are used in highway and runway pavement construction, with each mixture catering to a specific need. These mixtures vary in type and percentage of aggregates and asphalt used and consequently exhibit marked differences in their response. The main thrust of this research is to provide experimental data which would be helpful in determining the efficacy of the constitutive models that have been developed for these hot mix asphalt mixtures. Here we attempt to provide experimental data in the raw form for Sand Asphalt mixtures that would be helpful in the theoretical modeling efforts involving asphalt materials using a continuum point of view. For example the data obtained can be of immense help to evaluate the constitutive model developed by Murali Krishnan and Rajagopal. The Sand Asphalt mixture in their model is modeled as `homogenized' single constituent due to the peculiarity of its makeup. The constitutive model of Murali Krishnan and Rajagopal is based on a thermodynamical framework for materials possessing multiple natural configurations (multiple stress free states) to derive the constitutive equations. Recently an Orthogonal Rheometer was built to characterize the granular solids by Gupta and Rajagopal which was later used by Baek in the torsional mode. In this work we have used the same Torsional Rheometer with some minor modifications in the design to measure some general properties of Sand Asphalt mixtures. Sand Asphalt mixtures, due to their non-linear viscoelastic character, exhibit `normal stress effects' and `stress relaxation'. The Rheometer that we used was able to capture these responses with high precision. We have laid out proper procedures for the further testing of asphalt related mixtures. A typical sand asphalt mixture sample in cylindrical shape was used as the test specimen. From this work some interesting data was obtained. A remarkable observation was that as the shear rate is increased, the normal force and torque generated initially decrease, but beyond a certain shear rate they attain a constant value.

<p>The complex nature and composition of regolith cover in Southern Africa is a major challenge to geochemical mapping for concealed mineralization. Some of the setbacks to successful geochemical exploration may be ascribed to the use of various partial extraction techniques,without a profound understanding of the regolith components and their composition. This investigation therefore focuses on the use of hydroxylamine partial extraction geochemistry for geochemical mapping in regolith over two contrasting environments viz / aeolian sand-calcrete regolith over Au mineralization at Amalia Blue Dot Mine in South Africa and lateritic regolith covering the Ni-Cu deposit at Kabanga Main and Luhuma in Tanzania. Regolith samples from the above areas were sieved and extracted with hydroxylamine hydrochloride solution and analyzed for multi-element by AAS and ICP-MS techniques. A stepwise optimization of the hydroxylamine extraction technique of samples from both areas was carried out and incorporated into the analytical programme (in a pilot study). Results of hydroxylamine partial extraction generally gave better anomaly contrast and reflection of bedrock mineralization than the conventional aqua regia techniques that were previously used in the region. The results however show that lateritic regolith may be best extracted using 0.25M hydroxylamine while 0.1M concentration appears most suitable for extraction of aeolian-calcrete regolith. The above results are corroborated by principal component analysis of the analytical data that show various element associations, e.g. with Fe-Mn oxides while others possibly belong to the loosely adsorbed or exchangeable group. The&nbsp / gochemical maps in the pilot study areas at Amalia, Kabanga and Luhuma show elevated element contents or clusters of anomalies of diverse elements associated with Fe-Mn oxides. Geochemical mapping at Kabanga with deeply concealed mineralization however shows variability of subdued element patterns over mineralized areas. Geochemical signatures associated with hydroxylamine hydrochloride partial leach are therefore characterized by a lower geochemical background than that using conventional aqua regia leach. This study leads recommending for further investigations into partial extraction of the exchangeable group of elements, possibly using ammonium acetate.</p>

Terrestrial animals encounter natural surfaces which comprise materials that can yield and flow such as sand, rubble, and debris, yet appear to nimbly walk, run, crawl, or climb across them with great ease. In contrast, man-made devices on wheels and treads suffer large performance loss on these surfaces. Legged locomotion thus provides an excellent source of inspiration for creating devices of increased locomotor capabilities on natural surfaces. While principles of legged locomotion on solid ground have been discovered, the mechanisms by which legged animals move on yielding/flowing surfaces remain poorly understood, largely due to the lack of fundamental understanding of the complex interactions of body/limbs with these substrates on the level of the Navier-Stokes Equations for fluids. Granular media (e.g., sand) provide a promising model substrate for discovering the principles of legged locomotion on yielding/flowing surfaces, because they can display solid- and fluid-like behaviors, are directly relevant for many desert-dwelling animals, can be repeatably and precisely controlled, and the intrusion force laws can be determined empirically. In this dissertation, we created laboratory devices to prepare granular media in well-controlled states, and integrated biological, robotic, and physics studies to discover principles of legged locomotion on granular media. For both animals and bio-inspired robots, legged locomotion on granular surfaces must be achieved by limb intrusion to generate sufficient vertical ground reaction force (lift) to balance body weight and inertial force. When limb intrusion was slow (speed < 0.5 m/s), granular forces were independent of intrusion speed (dominated by grain-grain and grain-intruder friction) and generally increased with intrusion depth (due to granular hydrostatic pressure). Locomotor performance (speed) depended sensitively on limb kinematics, limb morphology, and the strength of the granular media, which together determined vertical force balance (or lack thereof). Based on these findings, we developed a granular resistive force theory in the sagittal plane as a general model for calculating forces during low-speed intrusions relevant to legged locomotion.

Albertas oil sands are located in the boreal forest where surface mining disturbs huge tracts of land. One such area, Syncrude Canada Ltd.s Mildred Lake mine, contains waste overburden (OB) piles which can be saline and sodic (SSOB). The objectives of this research were to 1) determine SSOB material impacts on planted tree root distributions, 2) quantify root activity to identify plant species growing at depth, and 3) document coarse woody root structure for planted trees. Root distributions for three mixedwood stands on reclaimed OB in relation to electrical conductivity (EC) and sodium absorption ratio (SAR) were examined using soil cores. Root distributions followed a similar pattern with soil depth as those from undisturbed boreal forest stands and appeared unaffected by the SSOB at this stage; however, future monitoring will be required as the stands mature. Root activity was assessed for jack pine (jP) and white spruce (wS) stands on tailings sand (TS) and OB using a strontium (Sr) chloride tracer. Understory and tree foliage was collected prior to and after application to measure Sr concentration in the control, broadcast, and depth treatments. A small proportion of roots grew in the OB material regardless of its chemical properties. Results from the Sr tracer study suggested that these roots were probably from the clover, sow thistle, and grasses. Planted trees showed little to no change in Sr tissue content suggesting that there were little to no roots in the treatment zones, the understory species out-competed the trees for Sr accessibility, or the tracer was diluted in the tree biomass to undetectable levels. Root systems of planted jP trees older than 10 years and older than 20 years on TS and OB were excavated and the number and diameter of lateral roots, the degree of kinking and coiling, and the presence of a taproot were recorded. Excavated trees showed poor taproot development on 70% of the trees and numerous root deformities, suggesting that more emphasis is needed in correct planting techniques and good planting stock to ensure proper root development. Roots are critical components of boreal forest ecosystems; without healthy root systems productivity may decline, stands may be susceptible to windthrow, and general forest health may suffer.

Leishmaniasis is a disease affecting more than 12 million people worldwide. It is caused by the protozoan parasite Leishmania, which is transmitted to humans and dog hosts through bites of infected sand flies belonging to genus Phlebotomine. Several studies have shown Polymerase Chain Reaction (PCR) to be effective for the diagnosis of VL in clinical samples compared to the classical methods. The aims of this study were first to compare four different sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and furthermore to find a method that is sensitive, rapid, cost benefit, simple and easy to perform. Two preparation methods were compared for the isolation of leukocytes (with Ficoll and Tris –EDTA buffer) and two DNA isolation methods (with Proteinase K and QIAgen kit). From the methods that were compared, lysis of erythrocytes with TE and the QIAgen kit seems to be the most suitable to use.

This thesis studies methane hydrate crystal formation and decomposition at 1.0, 4.0 and 7.0°C in a new apparatus. Hydrate was formed in the interstitial space of a variable volume bed of silica sand particles with an average diameter equal to 329μm (150 to 630μm range). The initial pressure inside the reactor was 8.0MPa for all the formation experiments. Three bed sizes were employed in order to observe the effects of the silica sand bed size on the rate of methane consumption (formation) and release (decomposition). The temperature at various locations inside the silica sand bed was measured with thermocouples during formation and decomposition experiments. For the decomposition experiments, two different methods were employed to dissociate the hydrate: thermal stimulation and depressurization. It was found that more than 74.0% of water conversion to hydrates was achieved in all hydrate formation experiments at 4.0°C and 1.0°C starting with a pressure of 8.0MPa. The dissociation of hydrate was found to occur in two stages when thermal stimulation was employed whereas three stages were found during depressurization. In both cases, the first stage was strongly affected by the changing bed size whereas it was not found to depend on the bed size afterwards.

Process water is used for cooling and for transporting material in all kinds of industries. To clean the water for reuse, various types of filters can be used. Many conventional process water treatment plants incorporate sand filters, which readily clean the water from suspended matters. However, at some circumstances the sand filters do not remove high enough concentrations of metals. This master thesis compares the water treatment abilities of activated cork, produced by Spikes &amp; Cogs AB, to those of the sand filters used at steel making company Ovako Hofors AB in Hofors. As an on-site pilot study, the thesis investigates the cleaning capacity of three types of activated cork filters: Fats, Oils and Solvents (FOSS) filter, Fast Acting Digesting Enzymes (FADE) filter, and Metal Adsorption and Concentration (MAAC) filter. The cork filters were compared to the sand filters during normal operation and, because of previous problems with the stability of the sand filter performance, during stress tests. The results show that the cleaning capacity of the sand filters is higher than the cleaning capacity of the cork filters at normal operation. At the conditions of the stress tests, at which the sand filters do not function, the cleaning capacity of the cork filters was somewhat lowered but was still well within acceptable limits. An important result from the experiments is that the cork filters neutralize the pH. The sand filters are sensitive to changes in the pH, meaning that the cork filters could function as a buffering unit prior to the sand filters.

The purpose of the study is to find a suitable method for removal of iron and manganese considering local economic and environmental aspects. El Salvador is situated in Central America with a coast line towards the Pacific Ocean. The country borders Guatemala and Honduras. Aguilares is a town situated in the department of San Salvador, with a population of approximately 33,000 people. Currently, the population is provided with water for about two hours per day, since it is the highest capacity of the existing wells. During these two hours many households fill a small tank with water to use for the remainder of the day. The water is not safe to use for oral consumption because of the levels of bacteria and other contamination. One of the wells, situated in the community of Florída is not in use at this date because of the high levels of Iron and Manganese in the ground water which cannot be removed with the present technique.Ground water is naturally pure from bacteria at a depth of 30 m or more, however solved metals may occur and if the levels are too high the water is unsuitable to drink. The recommended maximum levels by WHO (2008) [1] for Iron and Manganese are 2 mg/l and 0.5 mg/l respectively.Literature and field studies led to the following results; Iron and manganese can be removed by precipitation followed by separation. Precipitation is achieved by aeration, oxygenation or chemical oxidation and separation is achieved by filtration or sedimentation.The different methods all have advantages and disadvantages. However the conclusion reached in this report is that aeration and filtration should be used in the case of Florída. What equipment and construction that should be used depends on economic and resource factors as well as water requirements, which is up to the council of Aguilares to deliberate.