Göttingen, Universiẗat, Diss., 2001.

Thesis (M.E.E.)--University of Delaware, 2007. / Principal faculty advisor: Ian Appelbaum, Dept. of Electrical and Computer Engineering. Includes bibliographical references.

M.Sc. (Chemistry) / The preparatIon of fine powders having large surface are as was carried out using the Hot Kerosene Drying Method (H.K.D.). In this method an emulsion containing An aqueous solution of a sought after cation is emulsified along with kerosene having a high boiling point (200+ C). The emulsion is then added to a given amount of the kerosene at a predetermined temperature above the boiling point of water, in a drop-wise fusion, during which the water con concerned in the emulsion rapidly evaporates resulting in the solid accumulating on the bottom of the flask. The powder is then separable from the kerosene using conventional means. Tungsten and iron-containing powders were each, made according to this method. The preliminary preparations were carried out with tungsten containing emulsions. In an attempt to produce an emulsion having the smallest internal phase diameter, w/o iron-containing emulsions prepared using different concentrations of the emulsifying agents and various kerosene-water ratios, were photographed microscopically under high magnification. Sedimentation rates and the presence of phase separation of the emulsions were recorded. In this manner an optimum emulsion with regard to particle size and stability was found. This emulsion composition was employed to prepare a series of emulsions with varying concentratiOns of the iron sulphate solution. Powders were prepared from these emulsions by subjecting them to the ".K.D. procedure. In another series of experiments the effect of the kerosene bath temperature on the quality of the poWders was studied. The surface areas of the solids were determined by using a dynamic method, and these could be directly related to the particle size of the powders for purposes of comparison...

This investigation deals with the influence of initial curing periods and different curing environments, similar to those found in Middle Eastern countries, on the pore size distribution, permeability, water absorption and compressive strength of cement mortars and concretes made with and without pulverized fuel ash (pfa) and ground granulated blast-furnace slag (ggbs). Three 00 environments were chosen as follows: 1) 20C+70%RH, 2) 35C+70%RH, and 3) 45C+30%RH. To simulate in-place casting, the initial mix temperatures were controlled to be as close as possible to that of the environment in which the mixes were to be kept and moisture loss was allowed to occur from only the top-as-cast face of the specimen. Durability of the mortar specimens was assessed using pore size distribution, oxygen permeability, air permeability and water absorption. In addition to strength, the following tests were carried out on the concrete specimens to assess durability: initial surface absorption (ISAT), water absorption,relative air permeability and porosity. An the tests carried out on all specimens were undertaken at an age of 28 days. 7be test results showed that the durability properties of all specimens were significantly improved as curing periods increased. While curing durations had some significant effect on the strength of OPC/ggbs samples, the effects on OPC and OPC/pfa were in general only minimal. Furthermore, as to the effects on the pore size distribution and permeability, a critical curing duration (beyond which no further significant changes in these properties were observed) was seen to exist which depended on both curing environment and cement type. Enviromnents hotter than 20C+70%RH adversely affected the durability properties of uncured samples of all mixes. Furthermore, the durability properties of plain OPC samples were adversely affected by the two hot environments when compared to 20C+70%RH for all curing durations. On the other hand, while OPC/pfa and OPC/ggbs samples cured for one day or more at 35C+70%RH showed similar or worse durability results compared with those cured at 20C+ 70%RH, better results were obtained at 45C+30%RH than in either of the other two environments. As to the effects on strength, for any given curing period, environments hotter than 20C +70%RH adversely affected the OPC and OPC/ggbs samples but not those containing pfa. AT 20C+70%RH,the pfa specimens showed generally similar or worse durability results and weaker samples than plain OPC for all curing periods. This trend was reversed in the two hot environments. On the other hand, while OPC/ggbs samples showed similar or worse durability results at 20C+70%RH and 35OC+70%RH compared to plain OPC, at 450C+30%RH the slag specimens showed better durability results for curing periods of one day or more. Tbe 28-day strength of OPC and OPC/ggbs concretes were similar to each other in all envimnments for all curing periods except for those which were uncured. The uncured OPC specimens were stronger than the slag specimens in all envimnments.

A petrographic study is made of the granitic and related metamorphic rocks at Harrison Hot Springs, B.C. this thesis contains a general treatment of the regional and structural geology of the general area. The petrography of the various rock types is discussed under two main headings the granitic rocks, and the metamorphic rocks. Heat given of by the intrusive magma converted the adjacent unmetamorphosed sediments to hornfelses of the cordierite-anthophyllite subfacies and pyroxene-hornfels facies. These rocks are arbitrarily subdivided into rock types on the basis of their mineraloglcal compositions, rather than on the field occurrence. These assemblages are discussed with reference to the facies classification and the mineraloglcal phase rule. It is concluded that the hornfelses were derived by thermal metamorphism of aluminous-chloritic argillaceous sediments; that the cordierite-anthophyllite hornfelses were originally rich in MgO and FeO metasomatism was not an important process In the formation of the metamorphic assemblages. / Arts, Faculty of / Geography, Department of / Graduate

MA (Economics) / Department of Economics / Tourism is regarded as a modern day engine of growth globally. In light of this, the South African government aims to increase tourism’s contribution, both direct and indirectly to the economy. In 2012 tourism in South Africa contributed 7, 9% (R189.4 billion) to Gross Domestic Product (GDP) and it is estimated to increase to R499 billion by 2020 (South Africa National Department of Tourism). The purpose of the study was to assess the sustainability of hot spring tourism in Limpopo Province with regard to their competitiveness and potential to contribute to the economy of the country. The study employed a Delphi technique which is designed as group communication process which aims to achieve a convergence of opinion on a specific real world issues. The research developed a set of appropriate indicators that determines hot spring destination competitiveness. Data was collected through two sets of questionnaires administered and addressed to experts in the Limpopo Department of Economic Development and Tourism; academic staff in the department of tourism at University of Venda and tourism managers and practitioners in the tourism hot spring sector. From the findings of the study, recommendations have been made to assist the Limpopo Department of Economic Development and Tourism in designing strategies to make hot spring destinations competitive and sustainable as a tourism activity in Limpopo province.

Erythromelalgia is a rare clinical syndrome characterized by heat, redness and intermittent pain in the extremities, being most frequent the bilateral development in the lower extremities. Local cooling brings relief to symptoms, while heating, physical exercises and use of stockings/socks intensify the discomfort. This condition can be primary or idiopathic or secondary to haematological disorders and vascular inflammatory and degenerative diseases. It is reported the case of an eighteen-year-old male who presented, at the early age of two, development of the symptoms of erythema, heat and pain followed by desquamation of hands and feet, in outbreaks, with intervals 4 to 5 years long between the crises.

Currently, Ghana does not use Hot Water Treatment (HWT) as a phytosanitary control measure for mangoes. The effect of HW on the quality of ‘Keitt’ mangoes in Ghana was evaluated. Mangoes were washed with chlorinated water or hot water treated at 47°C for 70 min and stored at 25°C for 8 days. There was no treatment*Storage effect (P> 0.05) on the variables studied. Mangoes TA decreased (P<= 0.05) and pH increased with storage time. HWT had no impact on mango quality but had 50% reduction in decay during storage.

No description available.

No description available.