Geologic hypotheses of Lake Tanganyika region, Zaire, drawn from ERTS imagery

Based on initial work in the Lake Tanganyika area of eastern Zaire, it has been concluded that ERTS imagery is extremely useful for reconnaissance level geologic mapping and analysis in this region of the humid tropics. In particular, ERTS imagery has proven useful for recognizing and mapping regional structural units, for recognizing major structural features, and for arriving at some preliminary hypotheses about the mineral potential of the area. Results so far indicate that ERTS imagery can make a major contribution to the development of the mineral resources of the country. Research has concentrated on applications of ERTS imagery in the field of cartography, geology, forestry, hydrology and agriculture. For the work in geology, a test site was chosen in eastern Zaire on the shore of Lake Tanganyika in the vicinity of the Lukuga River. This area was selected because of its varied geology and the existence of two frames of cloud-free ERTS imagery

Macromolecular derivatives of methotrexate and ferrocene as potential prodrugs in cancer chemotherapy

Cancerous diseases present a formidable health problem worldwide. While the chemotherapy of cancer, in conjunction with other treatment modalities, has reached a significant level of maturity, efficacious use of such agents is still restricted by numerous pharmacological deficiencies, such as poor solubility, short serum circulation lifetimes, and low bioavailability resulting from lack of affinity to cancer tissue and inadequate mechanisms of cell entry. More critically still, most drugs suffer from toxic side effects and a risk of drug resistance. In an attempt to enhance the therapeutic effectiveness of carcinostatic drugs, the concept of anchoring bioactive agents to polymeric carriers has proved to be a promising approach to overcome these deficiencies and was the main aim of this project. Water-soluble, biodegradable macromolecular carriers used were polyaspartamides, prepared by an aminolytic ring-opening process of polysuccinimide; polyamides obtained by ester-amine base-catalyzed polyaddition; and polyamidoamines prepared by Michaeltype addition polymerization. The drug-anchoring potential of carrier polymers was demonstrated by the coupling of methotrexate (MTX), ferrocene and platinum drug models. MTX was linked to carrier via polymer attached amine by N-acylation of linear aminefunctionalized polyaspartamide carriers with the acid group from methotrexate. Acylation was brought about by mediation of HBTU coupling agent. The resulting MTX content of the conjugates was in the range of 10-19% by mass. In the present dissertation, series of water-soluble ferrocene conjugates were synthesized as for MTX by N-acylation of linear amine-functionalized polyaspartamide carriers with 4-ferrocenylbutanoic acid. Acylation was brought about again by mediation of HBTU coupling agent. The resulting iron content of the conjugates was in the range of 6-13% by mass. Polymer-attached dihydroxylato-type ligands were used to anchor the platinum drug to the polymeric carriers. The platinum content of the conjugates was in the range of 6-8% by mass. A member of selected conjugates was submitted to the Department of Immunology, University of Pretoria, and to the School of Pharmacy, University of California, Los Angeles, CA, for biomedical activity assessment. In order to demonstrate the multidrug-binding capacity of the polyaspartamide-type carriers, ferrocene was co-conjugated to selected polymeric conjugates containing MTX or folic acid. The latter was used to ensure target-specific drug delivery

A Study of Support for the Bereaved in the Local Congregation

The bereaved often face the ongoing challenges of grief with little support from the Church. This study aimed to resource the Church with practical methodologies to help congregants cope with grief. The study examined the troubling issues the bereaved experience after the death of a loved one. Survey data was collected from ten United Methodist members and had lost an immediate family member within the past five years. The measure consisted of interviews and questionnaires. An email and a verbal announcement during church worship service built the sample. Findings reveal that approximately 90% of participants experienced grief and emotional effects after losing a significant person in their lives. Initially, participants reported that they were encouraged and supported by the Church\u27s efforts to provide pastoral care and meaningful worship experiences during the funeral of loved ones. However, once the funeral was over, they were left alone to face the reality of death and grief. A small percentage (10%) of the participants reported never receiving support from the Church. Thus, it has been hard for many to attend worship on Sunday morning and church activities. This study underlines presence as an effective ministry to help the bereaved cope with grief. The researcher used the qualitative data from interviews and questionnaires to outline practical methodologies to provide meaningful and effective grief care ministry to congregants suffering from grief. Pastors and congregations interested in increasing service to those suffering from grief to take advantage of the provided practical methodologies to help congregants with grief

The Duration of Sub-Saharan African Civil Armed Conflict Episodes

The socio-economic question which this study intends to answer is one of global relevance. For quite some time now, civil wars on the African continent have been a major source of economic and social destruction resulting in excessive human suffering. The primary objective of this study will constitute the analysis of 32 armed conflict episodes across 17 countries between 1990 and 2014 throughout sub-Saharan Africa. Armed conflicts will be defined as the following: “a contested incompatibility that concerns government and/or territory where the use of armed force between two parties, of which at least one is the government of a state, results in at least 25 battle-related deaths” (UCDP, 2015)v. This study provides an assessment of the various factors which contribute to the duration of sub-Saharan Africa’s many armed conflict episodes as well as an empirical investigation into excess youth and utility theory

Short-term hourly load forecasting in South Africa using neutral networks

A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science, Johannesburg, 30 March 2018.Accuracy of the load forecasts is very critical in the power system industry, which is the lifeblood of the global economy to such an extent that its art-of-the-state management is the focus of the Short-Term Load Forecasting (STLF) models. In the past few years, South Africa faced an unprecedented energy management crisis that could be addressed in advance, inter alia, by carefully forecasting the expected load demand. Moreover, inaccurate or erroneous forecasts may result in either costly over-scheduling or adventurous under-scheduling of energy that may induce heavy economic forfeits to power companies. Therefore, accurate and reliable models are critically needed. Traditional statistical methods have been used in STLF but they have limited capacity to address nonlinearity and non-stationarity of electric loads. Also, such traditional methods cannot adapt to abrupt weather changes, thus they failed to produce reliable load forecasts in many situations. In this research report, we built a STLF model using Artificial Neural Networks (ANNs) to address the accuracy problem in this field so as to assist energy management decisions makers to run efficiently and economically their daily operations. ANNs are a mathematical tool that imitate the biological neural network and produces very accurate outputs. The built model is based on the Multilayer Perceptron (MLP), which is a class of feedforward ANNs using the backpropagation (BP) algorithm as its training algorithm, to produce accurate hourly load forecasts. We compared the MLP built model to a benchmark Seasonal Autoregressive Integrated Moving Average with Exogenous variables (SARIMAX) model using data from Eskom, a South African public utility. Results showed that the MLP model, with percentage error of 0.50%, in terms of the MAPE, outperformed the SARIMAX with 1.90% error performance.LG201

Characterisation of Al-Ti-B grain refiners prepared by aluminothermic reduction of TiO2 and B2O3

Student Number : 0314958W - MSc dissertation - School of Process and Materials Engineering - Faculty of Engineering and the Built EnvironmentMicrostructural characterisation was performed on Al-Ti-B grain refiners of different compositions prepared by aluminothermic reduction of TiO2 and B2O3 and dilution of the products in aluminium melts. The microstructure of the grain refiners showed needle-like TiAl3 particles as well as prismatic TiB2 particles. The TiB2 particles were coarser than those in conventional Al-Ti- B grain refiners. The microstructure also showed silicon particles and, in some cases, titanium carbide particles (TiC). The experimental grain refiners were subjected to rolling and reduced in thickness by 20, 40, 60 and 80%. The rolled samples were then heated at 625°C for 4 hours and allowed to cool slowly in the furnace. Significant changes in microstructure were noticed at 80% reduction. The flake-like and needle-like aluminide particles in the as cast microstructure were fragmented and aligned in the aluminium matrix, giving rise to short needle-like particles in parallel rows. These aluminide particles had rough edges which were rounded by heat treatment. The TiB2 particles were not affected in size or morphology by either the rolling or the heat treatment. The grain refining performance of the as cast materials was assessed. It was found that the experimental grain refiners had poorer performance than commercial grain refiners. The influence of mechanical and thermal treatments on the grain refining performance of the experimental Al-Ti-B grain refiners was also assessed. Cold working of the grain refiners had a positive influence on the grain refining performance promoting finer grain. Heat treatment of grain refiners after cold working was deleterious and led to a loss of grain refining capacity. The size and size distribution of TiB2 particles were determined related to grain refining performance and compared to theoretical models. A relationship was established between the size distribution of the TiB2 particles in the grain refiners and the grain size of inoculated aluminium. Grain refinement increased with decreasing proportion of coarse TiB2 particles in the grain refiners. This corresponded to a decrease in Ti and B contents and an increase in the Ti/B ratio

Home Cooking and Willingness to Pay: Local Blueberry Pancake, Muffin, and Banana Bread Mixes in a Take-and-Bake Experiment

This study explores measurable factors that influence consumer willingness to pay (WTP) for locally produced blueberry mixes: pancake mix, muffin mix and banana bread mix. The innovative aspect of this study is that the experiment took place at participants’ home. The post-preparation survey used a payment card approach to elicit WTP for each product tried as well as for the hypothetical third product not tried. A total of 101 out of 102 participants (99.01%) completed the process and returned the survey. Participants were instructed to prepare the products at home, sample the prepared product, and then evaluate the product and process. Sensory and preparation experience attributes for each recipe were considered as potential variables influencing overall WTP, including previous cooking experience for similar products, watching the Food Channel, and related shopping choices. A survey, along with two of the three recipes – a dry mix to be combined with locally grown frozen fruit - was distributed to potential consumers at diverse locations of study. The average WTP for the blueberry pancake mix was $3.45, muffin mix was$3.25, and the banana bread was $3.39. The estimated regression of the Censored Tobit model of WTP suggests that the estimate Trial of banana bread mix is significant. Four other estimates of Place, Gender, Age and Income also are significant depending on the product. The positive sign of some estimates of Trial, Blueberry Baking Experience, Education, Income, Gender, and Watching the Food Network showed that these factors have positive effect on WTP for some products. The paper develops the WTP models and also examines the experience versus the hypothetical effects on stated WTP. The results provide some measure of market opportunity, suggest positioning strategies, and also suggest strong returns to home trial marketing incentives for these products

Consumers buying decision process towards cosmetics: a comparison of the generations X and Y in Durban.

Masters Degree. University of KwaZulu-Natal, Durban.Understanding the factors influencing consumers through the buying decision process is of vital importance, most especially in recent times whereby marketing is more consumeroriented. The main purpose of this study was to compare the behaviour of two different generations (X and Y) group consumers through the cosmetics-buying decision process. However, this study used the buying model, which includes five stages; needs recognition, information search, alternative evaluation, purchase decision and post-purchase evaluation. This study used a quantitative research approach. A sample size of 379 (Westville campus and Howard college students born between 1965-1999) was determined using the probability random sampling method. Furthermore, data was collected by means of a survey questionnaire, and a satisfactory return rate of 99 per cent, or 377 questionnaires, were submitted for statistical analysis. After analysis result revealed that out of 377 respondents, the majority of them was from the generation Y with 60.2 per cent (n=227) whereas the generation X was only 39,8 per cent (n=150). Furthermore, findings indicated that through the cosmetics-buying decision process, each generation (X and Y) consumers’ needs are triggered by different motives. Most of the generation X consumers buy cosmetics products to satisfy the need to enhance beauty, whereas the generation Y is more likely to be driven by physiological needs than compared to generation X. Furthermore, the generation Y is more likely to be influenced by advertisements than compared to generation X. Findings suggested that during the cosmetics-buying decision process both generations (X and Y) consider social network platforms as a source of information, moreover the generation Y is also more likely to consider previous brands as a source of information than compared to the generation X. Findings suggested that loyalty, quality, and price are the basic criteria that generations X and Y consumers use during the cosmetics-buying decision process. However, generation Y is also partially likely to consider recommendations from sales persons. Finally, findings suggested that both generations (X and Y) use satisfaction as a basic criterion in the cosmetics-buying decision process. Nevertheless, statistical test results indicated that there are significant behavioural differences between the generation X and Y consumers during the cosmetics-buying decision process

Production of ion exchange membrane for hydrogen fuel cell

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering. Johannesburg, 2017Among of the components of the fuel cell, the polymer electrolyte membrane is critical to the performance and life time of the cell. Over the years the mechanical properties of the membrane, water management have tended to limit its wide spread commercialization as an alternative source of the renewable energy for portable power units. Fuel cell continues to attract extensive research interest as potential source of renewable energy. This work focuses on the production of ionexchange membrane (IEM) for hydrogen fuel cell, using cheap and locally available starting materials. The polystyrene-butadiene rubber (SBR) of different styrene and butadiene compositions, have been explored for functionality in fuel cell application. The production process was conducted in three stages: the first stage involved hydrogenation process followed by sulfonation process. The second stage entailed the production of carbon nano-spheres for the blending in the hydrogenated sulfonated polystyrene-butadiene rubber. The blending was also done between hybrid nanoparticles and hydrogenated sulfonated polystyrenebutadiene rubber. The third stage was the casting in thin film of blended solutions employing the evaporative method and the use of casting tape machine technique. The thin film was later on characterized and tested in a single fuel cell stack. Controlled hydrogenation of SBR employing catalytic method was achieved with maximum degree of hydrogenation in the range of: 90 – 92% for SBR with 23.5% styrene content and for SBR 25% styrene content 76 – 80% for SBR with 40% styrene content and 82 – 92% for SBR with 52% styrene content. The optimum conditions of this process were obtained using the Design of Experiments. SBR was also hydrogenated using a photocatalytic method and the percentage of hydrogenation for all SBR compositions used was found in the range between 60 and 74%. The hydrogenation results using the catalyst were higher compared to those obtained with the photocatalytic method. Therefore they were used to develop the kinetic model for prediction of hydrogenation process. Langmuir – Hinshelwood models were reviewed in this project as they explain these heterogeneous catalytic processes. Data from the kinetic tests were fitted to Langmuir – Hinshelwood models and reaction constants were found in the range between 0.445 h-1 and 0.610 h-1 for the reaction temperature between 20 and 30°C. The hydrogenated SBR of different compositions were effectively sulfonated with chlorosulphonic acid employed as first sulfonating agent of concentrations 0.15, 0.175 and 0.25M for SBR 23.5 and 25% styrene content, for SBR 40% styrene content and for SBR 52% styrene content, respectively. The degree of sulfonation was found in the range between 56 and 72% depending on the rubber composition. Trimethylsilyl chlorosulfonate used as the second sulfonating agent was like wise attached to the same polymer back bone and the degree of sulfonation was between 59 and 74% depending on the rubber’s styrene content. Non-conductive carbon nanospheres (CNS) of uniform size of about 46 nm were produced employing the non-catalytic chemical vapour deposition method at 1000°C. Acetylene and argon were respectively used as carbon source and carrier gas, in a reactor of 16 mm in diameter. Successful blending of 4 wt% nanoparticles and hydrogenated sulfonated styrene butadiene solution was accomplished by magnetic stirring technique combined with ultrasonication at 60% amplitude. The blended solution was casted to produce a thin film membrane of 156 μm thickness. Further the tensile strength test of the membranes has shown an increase in Young’s Modulus by 72-120% for all the rubbers. This test was done using TA.XTplus, Texture Analyser machine. The water uptake increment was in the range of 20-27% and thermal stability in the range of 2-20% depending on the rubber composition. Purchased electrodes from FuelCellsEtc (USA), were pasted on both sides of the membranes by the means of hot press at 125oC for about 5 minutes at a pressure of 40 kPa. The Membrane Electrode Assembly (MEAs) fabricated were tested in the fuel cell stack. The highest power density of approximately 85mW/cm2 was obtained for 52% styrene nanocomposite membrane with 4% hybrid nanoparticles at the current density of 212.41mA/cm2 and the efficiency was between 41 and 43%. MEA fabricated with Nafion112 membrane was tested and yielded the open cell voltage of 0.79V, power density of about 77.34mW/cm2 and efficiency of 45%. Results obtained disclose that the MEA with nanocomposites based SBR 52% styrene composition yielded higher power density and higher voltage than the one with Nafion 112 which is one of the fuel cell membranes available on the market. The results obtained revealed that the nanocomposite membranes with 4% hybrid nanoparticles (CNS + SiO2) had higher voltage than the one with 4% CNS. These optimum conditions obtained in this work may be adopted for a typical continuous production of the membrane for hydrogen fuel cell.MT201