Th. doct.-ing., vibrations et oscillateurs--Besançon, 1984. N°: 7.

Th. doct.-ing.--Besançon, École nationale supérieure de méc. et des microtech., 1982. N°: 2.

Brick clay deposits, in the area north of Cape Town, were formed as a result of three independent geological processes. The intrusion of the syn- to post tectonic granitoids into micaceous (indicated by the absence of halloysite; Orris, 1998), feldspathic Malmesbury sandstone beds, approximately 500 Ma ago, created a hydrothermal vein structure, which enriched the shale with feldspar/kaolinite and quartz, restricted to the vein network. This was followed by extensive in-situ weathering of these hydrothermally altered rocks resulting in residual kaolin deposits, the effects of which were more pronounced along the more permeable shear zones. The final process, formation of ball clay deposits, initiated by the erosion of the primary kaolinite deposits, which have been transported in water, together with organic material, to shallow depressions where clays were deposited. Brick clay is exclusively used for the manufacturing of clay brick products and must derive its value from the sales revenue generated from these products. Evidence from the two exploration programs described, suggests that the clay deposits explored has no value as individual deposits as the clay from both deposits lack specific ceramic properties to successfully manufacture clay bricks. It is however clear that if the clay from the two deposits is mixed in specific proportions; body mixes with ceramic properties suitable for light coloured clay face brick manufacturing is possible. The value of the beneficiated product, clay bricks, may then be used to determine the value of both clay deposits. Discounted Cash Flow Models (DCFM) and Net Present Values (NPV) were used to determine the fundamental value of the clay deposits explored, as it determines the time value of money (Kernot, 1999). These models clearly showed the dependency of the value of clay brick deposits on variables such as raw material quality, capital expenditure and clay brick yields. Geological, chemical and ceramic knowledge of individual brick clay deposits and the management of the raw materials extracted from these deposits is key to the profitable manufacturing of clay bricks. Risks, at the quarrying level, related to these aspects need to be managed to ensure the profitable and efficient functioning of the entire brick production process. / Dissertation (MSc (Earth Science Practice and Management))--University of Pretoria, 2007. / Geology / MSc / unrestricted

In the first part, the Compact Muon Solenoid (CMS) forward calorimeter design studies are presented. The forward calorimeter consists of quartz fibers embedded in a steel absorber. Radiation damage studies of the quartz fiber and the absorber as well as the results of the first pre-production prototype PPP-I are presented. In the second part the Ωc0 search studies at the SELEX (E781) experiment at FermiLab are presented. 107±22Ωc0 events were observed in three decay modes. The relative branching ratio Ωc0 → Ω−π−π+π+)/Β(Ωc0→ Ω−π+)$ is measured as 2.00 ± 0.45 (stat) ± 0.32 (sys).

Thesis: M.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1982 / Bibliography: leaves 134-139. / by Bruce A. Robinson. / M.S. / M.S. Massachusetts Institute of Technology, Department of Chemical Engineering

<p> Metagreywackes of the Goldenville Formation, Nova Scotia, possess a well developed penetrative cleavage. Measurement of strain, based on quartz grain shape, indicates that much of the strain has been achieved by pressure solution of detrital quartz grains. Strain ratios in the system range from X/Z = 3.8 in cleavage zones, through 2.0 in intermediate areas, to 1.6 in lithons. The volume lost from cleavage zones ranges from 60 to 70 percent, while loss of volume to the system as a whole is 40 percent or greater. Strain due to plastic deformation is minimal, relative to the strain due to volume loss. The strain within the system is not homogeneous on a centimeter scale, but rather range from low values in mid-lithon zones to much higher values in cleavage zones. Lithon and intermediate areas are representative of the deformation history of the cleavage.</p> / Thesis / Bachelor of Science (BSc)

<p> UV radiation disinfection technology is an advantageous method of wastewater disinfection as it avoids the formation of chemical by-products typically found from chlorination. One challenge with this technology is avoiding fouling on the quartz sleeves in which the UV lamps are housed. In this study, using a model fouling system, the roles in fouling of light, and the constitution of the fouling media, are examined. The systematic determination of fouling by various mixtures of human serum albumin, humic acid, Ca^2+, and Fe^3+ was carried out on quartz slides in the presence and absence of UV (254nm) light. Fouling was assessed by the reduction in transmission of UV light through the quartz slides over time. It was determined that the most important factors were the concentration of..iron and protein, which apparently act synergistically to foul the surface. Other contributing factors to the magnitude of fouling include the flow rate and the age of the fouling solution. Most important was the presence of UV light. In all solutions examined, fouling was observed to a lower degree when the system was exposed to light. On the other hand, XPS analysis has demonstrated differences in the nature of the fouling layer on the surface exposed to UV light compared to that in the dark. </p> <p> It is generally accepted that low energy surfaces are less easily fouled than polar surfaces. Therefore, hydrophobic modification of the quartz by a series of different silane coupling agents was undertaken. Irrespective of the nature of the coating (alkylamine, alkyl, aryl, fluorocarbon, silicone), the rate and magnitude of fouling on the surface were comparable to the unmodified quartz. However, the more hydrophobic surfaces were easier to clean. </p> / Thesis / Master of Science (MSc)

<p> Three conformable units of fine-grained quartz-feldspar porphyry were mapped in the Berry River Formation, Warclub Group, Northwestern Ontario. The largest unit (Unit 1) is compared geochemically and petrographically to quartz-feldspar porphyry intrusions and tuffs in the area with the aim of determining the method of emplacement of the porphyry unit (Unit 1), and consequently the other two units.</p> / Thesis / Bachelor of Science (BSc)

<p> An investigation is reported on the kinetics of Ca0-β quartz solid state reaction on basal and prism planes of β-quartz at temperatures in the range between 1000 degrees Celsius and 1200 degrees Celsius. Excess lime present in all the samples ensured ensured the formation of c2s (dicalcium silicate) only. The thickness of the c2s product layer was measured on a Zeiss camera microscope Ultraphot II. The line scans for the distribution of Ca and Si across the reaction layer were obtained on the electron microprobe analyser. The kinetics of the reaction on basal and prism planes of a-quartz in wet and dry nitrogen atmospheres in the temperature range considered was studied by measuring the thickness of c2s as a function of time of reaction. </p> <p> The CaO-β quartz reaction was found to be anisotropic, the basal plane reaction being faster than the .Prism plane reaction. The reaction on both basal and prism planes in the temperature range between l000°C and 1200°C was found to be enhanced in the presence of moisture. The enhancement due to the presence of moisture was found to be more on the basal plane reaction than on the prism plane reaction. This appears to be due to the fact that different polymorphs of c2s with different sensitivities to the presence of moisture are produced on different crystallographic planes of a-quartz considered. The activation energies for the reaction on basal plane and prism plane were found to be about 53 kcal/mole and 63 kcal/mole respectively. They have good agreement with the activation energies of 55 kcal/mole and 65 kcal/mole for Ca diffusion in a-c2s and a-c2s respectively as reported by Lindner. </p> / Thesis / Master of Engineering (MEngr)

No description available.