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The genesis and characteristics of the gold mineralisation in the area between river Malaba and river Solo in Busia district, South Eastern Uganda.

(Makerere University, 2005-07) Mbonimpa, Alex

The present study was carried out in Busia district, in eastern Uganda and covered an area of about 100 km2. It involved rock, soil and stream sediment sampling and field observations (e.g. structures, terrain, etc.). The area has two types of gold deposits: quartz vein-hosted deposits and Banded Iron Formation (BIF) -hosted deposits. In the BIF-hosted deposit type, no ore minerals are visible to the naked eye and any gold mineralisation therein is perhaps disseminated. Thin section studies show that the rocks in the area are metabasalts, quartz diorites, quartz monzodiorites, monzodiorites, monzogranites syenogranites and banded quartzites (BIF). Polished sections of the quartz vein-hosted type were also studied by reflecting microscope and Electron Microprobe (EMP). The main ore minerals are pyrite, magnetite and ilmenite but pyrrhotite, chalcopyrite, covellite, galena and rutile are also present. EMP analyses of ore minerals indicate that gold in the Busia quartz vein deposits occurs as electrum or native gold inclusions in pyrite with fineness in the range of 451 – 863. It also occurs as invisible gold in the sulphide minerals. Pyrrhotite has the highest values of invisible gold (up to 4.33 wt % Au) but its volume proportion is insignificant. Invisible gold in pyrite however may contribute significantly to the total gold budget of the Busia quartz vein deposits since pyrite is abundant. Fluids intruding the basaltic country rocks through NW-trending fractures led to the formation of the quartz veins and the precipitation of the sulphides and the gold. This points to an epigenetic origin for the quartz vein hosted mineralisation. The Buteba granite is unlikely to be the source of the mineralising fluids. Isotope/ REE studies and age determination of the mineralisation need to be done to determine the genesis of the mineralising fluids. Stream sediment, soil and rock samples were analysed chemically by AAS and XRF methods. Of the three areas proposed for follow-up by Mroz et al. (1991), the Tira area has the first priority soil anomaly (up to 4.8 ppm Au) followed by the Osapiri area (up to 2.8 ppm Au). Stream sediment anomalies are found on rivers Nakola, Tira and Aget. Generally, the stream sediments have higher gold concentrations (up to 38.6 ppm Au) than the soil samples. Lead shows the distribution most similar to that of gold in the rock, soil and stream sediment samples and so is the best indicator element for gold.
Biomass and hydropower potential and demand in the Uganda Albertine Rift Region

(Makerere University, 2006-08) Cisirika, Katcho Karume

This study assessed the hydropower potential in the Albertine Rift Region and suggested electricity as an alternative to reduce the pressure on biomass. Hydrological and topographical conditions of the region were analyzed in GIS environment, in order to identify potential hydropower sites. River flow measurements were used to estimate capacity of each site in power generation. A total of 51 potential sites were identified with an aggregate minimum potential (river runoff) power generation capacity of 896 MW. This study also assessed the current trend of biomass consumption in Uganda Albertine Rift Region, and explored possible solutions for sustainable development of these resources in the future. The biomass trend was first assessed by analyzing satellite images (a total of 45 satellite images) for the years 1984, 1990 (taken as control point), 1995, 2000, and 2003. Results showed that under current conditions, Ugandan Rift Region biomass consumption rate may induce depletion of the resource to the minimum value around 2018. Sustainable resource management constraints biomass consumption to be proportional to the production before 2006 up to 2020 and constant afterwards. The biomass dynamics was investigated by solving Schaefer’s model improved by Holling’s model for Uganda Albertine Rift Region conditions, assuming that in absence of harvesting and at low densities, the biomass resources grow at the intrinsic rate. When the stock is at equilibrium, the surplus production is basically cut, while if the stock is growing, surplus production is consumption plus net growth of the biomass resource. Moreover, the behaviors of the consumers of the Ugandan Albertine Rift region biomass do mimic two effects proposed in the Supruce Budworm model with the use of Holling’s type III consumption equation. First, they tend to increase their dependence on the forests when the forest density increases and also the population of people depending on forests seems to grow when the forest densities increase. Holling (1959) disc equation assumes the principle of time budget, that is, consumers spend their time on two major activities; namely, searching for desirable species and processing their harvest. This equation was used to develop a model for the dynamics of biomass in the Uganda Albertine Rift Region. To avoid overdependence on biomass, a deliberate policy needs to be strengthened to take advantage of the abundant hydro-potential in the districts and other renewable energies. A shift in the present energy matrix towards renewable energy sources and measures to improve energy efficiency will greatly contribute to solving a broad range of issues. The low cost of some Small Hydropower schemes may prove more economic than extension of the existing Uganda national electric grid to isolated areas like in Uganda Albertine Rift Region. Liberalization policies should be encouraged so that the private sector is more involved in energy production and delivery. These hydropower plants are relatively cheap to develop in international terms. Key words: Biomass, consumption, growth rates, land-use, Uganda, environment, dynamics, hydropower, energy.
Development of an appropriate solar radiation model for Uganda

(Makerere University, 2006-09) Mubiru, James

Sizing of solar energy systems is necessary in order to optimize their output. This requires a database of solar radiation for locations for which the systems are being assessed. Solar radiation data is also required in modeling a building’s thermal performance, as input into ecological and crop models and evaluation of long-term effects of climatological changes. Solar radiation data can be provided through measurements. In Uganda, measurements of total solar radiation and its two components (diffuse and direct) have been carried out for a few locations, such as in Kampala, Entebbe and Gulu. It is difficult to have measurements from all locations of interest because the measuring instruments are expensive to purchase and install. An alternative to obtaining solar radiation data is to estimate it either by use of an appropriate solar radiation model or interpolation of the few existing records. Interpolation results into solar radiation maps. This study had an overall objective of developing an appropriate solar radiation model for Uganda. This was achieved through measurement of diffuse and direct solar irradiation and subsequent computation of total solar irradiation at four selected locations in Uganda; investigation of relationship between total, diffuse, direct solar irradiation and a selection of meteorological and geographical parameters, which lead to an appropriate solar radiation model for Uganda; prediction of total, diffuse and direct solar irradiation using this model; interpolation of measured and predicted total, diffuse and direct solar irradiation and subsequent drawing of solar radiation maps for Uganda. The uncertain nature of solar radiation and the modeling abilities of Artificial Neural Networks (ANN) have inspired the application of ANN techniques to predict solar radiation. ANN are intelligent systems that have the capacity to learn, memorize and create relationships among data. They are ideal for modeling non-linear, dynamic, noise-ridden and complex systems. A survey on existing literature shows limited usage of the ANN method to predict total, diffuse and direct solar radiation. Much of the work on the prediction of solar radiation has been done using the empirical method. Estimation of total solar radiation using ANN has been done for locations in North and South America, Europe, Asia, Middle East and some parts of northern and southern Africa. Solar radiation predictions using ANN in eastern and central Africa are non-existent. Therefore the study utilized the ANN method to predict total solar irradiation and its two components. The data from the four measurement sites in Uganda were split into two such that the dataset from three stations, that is, Mbarara, Lira and Tororo, was used for training Neural Networks and formulating empirical models. The dataset from the Kampala station was reserved for validating both the ANN and empirical models. A typical neural network is made up of input, hidden and output layers. The present study utilized meteorological parameters as inputs and solar radiation as output from the neural network. A feedforward back-propagation neural network was used in this study with six input variables for the prediction of total solar irradiation, which included: sunshine hours, cloud cover and maximum temperature, together with latitude, longitude and altitude. The diffuse component had as input the following variables: latitude, longitude, altitude, total solar irradiation, sunshine hours, average temperature, relative humidity and cloud cover; whereas the direct component had: latitude, longitude, altitude, total solar irradiation, sunshine hours and maximum temperature. There was a challenge in determining which transfer function and training algorithm to use in training the neural networks, and also determining the number of hidden layers and number of neurons in the ANN structure. Total, diffuse and direct solar irradiation values were estimated for eight other stations in Uganda where measurements of solar radiation were not made. This was done using the appropriate ANN models. Consequently, a pool of measured and estimated values of solar irradiation was created and used for the interpolation task. Moving Average interpolation method was used for interpolating total solar irradiation and its two components. The ANN architecture designed was a feedforward back-propagation with one hidden layer and tangent sigmoid, as the transfer function. The output layer utilized a linear transfer function and Levenverg-Marquardt as the training algorithm. The number of neurons in the hidden layer was fifteen for total solar irradiation, eighteen for diffuse solar irradiation and six for direct solar irradiation. The ultimate part of the design process of the ANN model was the variation of the inputs to the network and evaluation of the corresponding ANN model in pursuit of the most appropriate prediction model. The evaluation involved correlation and error analysis using mean bias error (MBE) and root mean square error (RMSE). The appropriate ANN model for prediction of total solar irradiation was one which had the following input variables: latitude, longitude, altitude, sunshine hours, maximum temperature and cloud cover. The model yields predictions with MBE=0.069MJm-2 and RMSE=0.504MJm-2. The appropriate ANN model for prediction of diffuse solar irradiation was one which had the following input variables: latitude, longitude, altitude, total solar irradiation, sunshine hours, average temperature, cloud cover and relative humidity. The model yields predictions with MBE=0.018MJm-2 and RMSE=0.268MJm-2. The appropriate ANN model for prediction of direct solar irradiation was one which had the following input variables: latitude, longitude, altitude, total solar irradiation, sunshine hours and maximum temperature. The model yields predictions with MBE=0.005MJm-2 and RMSE=0.197MJm-2. A pool of measured and estimated values of total solar radiation and its two main components have been interpolated, successfully. The results are three sets of solar radiation maps for Uganda, with normalized percentage root mean square errors of 2.5%, 3.0% and 1.8% for the interpolation of total, diffuse and direct solar irradiation, respectively.
Characterization of anthocyanins from selected plant species in Uganda

(Makerere University, 2008-10) Byamukama, Robert

Different plant species were collected from different parts of the country in the period 2003 to 2007. Extraction of the plant material collected was done using methanol acidified with various amounts of trifluoroacetic acid depending on the anthocyanins present in each particular plant species. Purification of the crude methanol extracts was done by partition (several times) against solvents, ethyl acetate and petroleum spirit of boiling range 40-600C. Further purification and separation was performed using ion exchange resins (amberliteXAD-7 and sephadex LH-20) and toyopearl LW- 40, packed in chromatographic columns. Final separations of the anthocyanins were achieved by preparative High Performance Liquid Chromatography. The anthocyanins were identified by a combination of Thin Layer, High Performance Liquid Chromatography (HPLC), online UV spectroscopy, one Dimensional and two Dimensional (1H &13C) Nuclear Magnetic Resonance spectroscopy (NMR) techniques and Liquid Chromatography-Mass spectrometry (LC-MS). The quantitative determination of anthocyanins was accomplished with Analytical HPLC using reference samples isolated under the same conditions. The colors of the Hippeastrum cultivars were described by the CIELab coordinates L* (lightness), C* (chroma) and hab (hue angles). Twelve plant species, which included; Rubus pinnatus, Rubus rigidus, Carissa edulis, seven Hippeastrum cultivars, Acalypha hispida and Ricinus communis, were analysed. Ten structures of anthocyanins including four novel ones were characterised in this study and five papers (Paper I –V) (attached in Part II) have been published.
Characterization of selected pesticide residues in sediments of the Ugandan side of Lake Victoria

(Makerere University, 2009-06) Wasswa, John

This study investigated the role of biogeochemical processes in influencing bio-availability and biodegradation of selected pesticides in Lake Victoria. Due to the hydrophobicity nature of most pesticides, sediments which serve as sink to the less water soluble chemicals were selected as a matrix of study. To achieve the set objective, an inventory of the pesticides use in the Ugandan side of Lake Victoria catchments was made, seasonal variability of pesticide concentrations in sediments were determined, followed by sorption and pesticide degradation studies within the lake sediments. Information on the pesticides used was gathered using questionnaires and professional interviews. Surface sediment samples were collected using a corer, extracted for pesticide residues using solid dispersion methods and extracts cleaned up using gel permeation chromatograph – GPC. Analysis for pesticide residues in extracts was done using a temperature programmed Gas Chromatograph equipped with a Nitrogen Phosphorous Detector and an Electron Capture Detector. External and inter-laboratory confirmatory tests were done using a dual column and dual detector approach coupled with a sulphuric acid treatment method of selected extracts. Validation of selected samples was done using a Gas Chromatograph equipped with a Mass Selective Detector. Sorption experiments were conducted in mixed solvents (methanol-water) systems and sorption coefficients in aqueous systems were obtained using the theory of the Solvophobic model. Degradation experiments to determine the kinetics of pesticide transformation by different microbial communities were defined in terms of the extractable concentrations based on method extraction efficiency. The presence of microbial communities within the lake sediment was established using a DNA screening technique. Results from the survey indicate the major challenges associated with pesticide use in Uganda as being use of un-registered pesticides, inappropriate packaging, storage, disposal and human exposure due to poor handling of the pesticides and their containers. A total of eighteen pesticide residue/metabolites have been identified and quantified within Lake Victoria sediments with chlorpyrifos recording the highest mean value of 4.18 μg/kg (dry weight) and endosulfan sulfate being the most frequently detected (42%) pesticide residue. The study has also detected residues of pesticides which are not registered for use in Uganda. Sorption studies have indicated that sorption on containers can cause grave errors in the estimation of sorption coefficients, especially for those chemicals with very low water solubility. Chlorpyrifos has been found to have a higher affinity to the lake sediment than both the β- endosulfan and α- endosulfan in that order. Degradation studies indicate that α-endosulfan, β-endosulfan and chlorpyrifos degrade faster in unsterilized than in sterilized sediment samples of Lake Victoria, suggesting that microorganisms contribute to the degradation processes of the three pesticides within the lake sediment. A DNA screening for the presence of bacteria that degrade pesticides within Lake Victoria has indicated presence of microbes in the lake environment that are capable of degrading phenyl derived pesticides, toluene derived pesticides and xylene derived pesticides. The fate of pesticide residues within Lake Victoria has been described using the "Quantitative Water Air Sediment Interaction" (QWASI) model. With this model, it has been predicted that the residence times (years) of chlorpyrifos, α –endosulfan, β- endosulfan, endosulfan sulfate, pp- DDT, HCHgamma, and chlordane within the lake system are; 3.3 , 6.3, 6.1, 3.2, 0.4, 14.0 and 1.7, respectively.
Post-harvest handling practices and physico-chemical characteristics of shea (Vitellaria paradoxa) fruit in Uganda

(Makerere University, 2009-11) Omujal, Francis

This study assessed the post harvest handling practices and physico chemical characteristics of shea butter in the parkland areas of Uganda. To investigate post harvest practices of shea butter (Vitellaria paradoxa) fruit, a total of 275 respondents were interviewed between July 2007 and January 2008. The collected socio-economic data were coded, entered in SPSS computer programme and analysed. In the same period, fresh shea fruit pulps were collected, dried and analyzed for proximate and mineral compositions. The shea butter oil extracted from the shea kernels of the shea fruit were also analysed for variability in physico chemical characteristics and fatty acid profile extracted by n-hexane solvent, traditional boiling and mechanical cold pressing methods. The proximate analysis showed that the shea fruit pulp, crude oil, crude fibre, crude protein, total carbohydrate, vitamin C and caloric value contents ranged between 1.5-3.5%, 10-15%; 3.1-4.2%, 61-64%, 85.59-124.86mg/100g and 248-256 Kcal/100g, respectively. The mineral composition of the shea fruit pulp consisted of calcium 35.18-95.58 mg/100g, potassium 42.04-63.55 mg/100g, magnesium 18.14-24.21mg/100g, sodium 7.07-18.12 mg/100gm and iron 3.41-3.76 mg/100g. The shea seed kernel butter/oil content ranged between 41-54% and the physico chemical characteristics such as colour, refractive index, viscosity, acid value, peroxide value, saponification value, iodine value and α- tocopherols ranged between orange to orange–yellow, 1.670-1.690, 2.4-2.8cP, 2.3-12.59mgKOH/kg, 2.10-2.50meq/kg, 160- 192mgKOH/g, 39.21-41.37 I2g/100g and 26.3-44.4mg/100g, respectively. The shea butter fatty acid profile: palmitic , stearic, oleic, linoleic and arachidic acid fatty acids ranged between 6.52-8.12%, 28.65-30.94%, 55.54-57.63%, 6.18-7.79% and 0.65-0.90%, respectively. The physico-chemical characteristics of shea butter extracted by n-hexane solvent extraction, traditional boiling and cold pressing methods for the colours, refractive index, viscosity, acid value, peroxide value, saponification value, iodine value and α tocopherols ranged between yellow-orange to yellow-red; 1.468-1.469, 2.4-2.8cP, 2.3-6.9mgKOH/kg, 2.2-5.09mEq/kg, 145-192mgKOH/kg, 36-38 I2/100, 34.4-45.5mg/100g while the fatty acid profile: palmitic , stearic, oleic, linoleic and arachinic acid fatty acids ranged between 6-8%, 29-31%, 55-57%%, 6-8%and0.65-0.98%, respectively. While the proximate and mineral composition of the shea fruit pulp makes shea fruits a potential nutritious fruit in the parklands, the physico-chemical characteristics and fatty acid profile of shea butter on the other hand make it a suitable raw material for food, cosmetic and pharmaceutical products. The quality of shea butter oil is also comparable to other edible oils such as soya bean oil (Glycine max). The indigenous post harvest handling practices of shea butter in Uganda is appropriate, however, there is a need to investigate further their influence on quality of shea butter..
Iodisation of Lake Katwe salt, Kasese District

(Makerere University, 2009-11) Loum, Janani

The raw rock salt was analysed for chemical composition, refined and then iodised. The selected species determined are those known to hinder iodine retention in edible salt, namely; sulphates 20.7 % w/w, carbonates 31.7 % w/w, zinc 18 ± 4 ppm magnesium 945 ± 3 ppm, iron 168 ± 2 ppm and calcium 74 ± 3 ppm as ionic species were determined. The total amount of chloride was 1.54 % w/w. Purification was by fractional crystallization, precipitation, and adsorption techniques. This yielded 85 % w/w salt as sodium chloride. The impurities were reduced markedly with sulphate 3.83 % w/w, carbonate 1.42 % w/w, zinc 4.22 ± 0.15 ppm, magnesium 7.64 ± 2 ppm, iron 7.40 ± 0.25 ppm and calcium 4.40 ± 0.3 ppm. Iodisation of the salt was done by addition of potassium iodate ( 0.378 g ) to the refined salt ( 200 g ) to give 100 ppm of iodine. Iodine retention was determined by iodometric titration conducted on the salt sample for two weeks. The quantity of iodine retained in the salt varied between 82.3 ± 3.8 ppm and 99.8 ± 9.0 ppm.. The salt can be profitably exploited if attention is focused to the manufacture of other products alongside salt e.g. fertilizers, carbonates, bicarbonate, stearate, and sulphate salts. This will subsidise on operation costs and reduce on the cost of the salt produced.
Gasification of biochar from empty fruit bunch in a fluidized bed reactor

(MDPI AG, 2010) Nsamba, Hussein Kisiki ; Salleh, M. A. Mohd ; Yusuf, H. M. ; Ghani, W. A. Wan Ab Karim

A biochar produced from empty fruit bunches (EFB) was gasified in a fluidized bed using air to determine gas yield, overall carbon conversion, gas quality, and composition as a function of temperature. The experiment was conducted in the temperature range of 500–850 °C. It was observed that biochar has the potential to replace coal as a gasification agent in power plants. Hydrogen gas from biochar was also optimized during the experiment. High temperatures favor H2 and CO formation. There was an increase of H2 over the temperature range from 500–850 °C from 5.53% to 27.97% (v/v), with a heating value of 30 kJ/g. The C conversion in the same temperature range increased from 76% to 84%. Therefore, there are great prospects for the use of biochar from EFB as an alternative fuel in power plants, as a renewable energy providing an alternative path to biofuels. Results from this work enable us to better understand syn gas production under high treatment temperatures.
Assessment of organochlorine pesticide residues in cows’ fresh and pasteurized milk sold from Kampala markets, Uganda

(Makerere University, 2010-05) Kampire, Edwige

Concentrations of organochlorine pesticides (Lindane, Aldrin, Dieldrin, Endosulfan, p, p’- DDT, o, p’-DDT and p, p’-DDE) residues in cows’ fresh and pasteurized milk samples from Uganda were determined using a gas chromatograph with an electron capture detector and confirmed with a gas chromatograph equipped with a mass spectrometer [GC-MS]. 54 fresh milk samples and 47 pasteurized milk samples were analyzed for organochlorine pesticides. Five organochlorine pesticides were detected in the milk samples; namely Aldrin, Dieldrin, Endosulfan, DDT and its metabolites and Lindane. The average concentration of lindane was 26 ± 1.7 μg/kg in fresh milk samples (n=54) and 22 ± 1.5 μg/kg in pasteurized milk (n=47). Endosulfan concentration was 4 ± 0.3 μg/kg in the fresh milk samples and 3 ±1.0 μg/kg in the pasteurized milk samples. p,p’-DDE contained mean concentrations of 9.5 ± 2.0 μg/kg in fresh milk and 8 ±1.0 μg/kg in the pasteurized milk samples. p, p’-DDT recorded an average concentration of 33 ± 6.9 μg/kg in fresh milk samples and 25 ±5.0 μg/kg in pasteurized milk samples. The average concentration of o, p’-DDT in fresh milk was 9 ± 2.0 μg/kg and in pasteurized milk it was 7 ± 4.0 μg/kg. The mean concentration of aldrin was 9 ± 0.7 μg/kg kg in fresh milk samples and 6 ±1.0 μg/kg in pasteurized milk samples. Dieldrin was 7 ± 4μg/kg in the fresh milk samples and 5 ± 5 μg/kg in the pasteurized milk. The concentration of sum-DDT was 52 μg/kg and was found to range from 3 μg/kg to 33 μg/kg in the fresh milk and was 41 μg/kg in pasteurized milk with the range of 7 μg/kg to 25 μg/kg. Although, most of the organochlorine residues detected were below the maximum limits set by the FAO/WHO, bioaccumulation of these residues is likely to pose health problems in higher organisms like human beings.
Facies analysis and sequence stratigraphy of the South East Lake Edward Basin, South Western Uganda

(Makerere University, 2010-12) Twinomujuni, Lauben

The south-east Lake Edward basin is the onshore part of the Block 4B exploration area which was licensed to Dominion Petroleum Limited in 2007. This area lies within the western branch of the East African Rift System (EARS). Dominion Petroleum Ltd is carrying out intensive oil exploration in the Lake Edward Basin whereby the researcher participated in some components of this exploration. This study impinges upon the economic potential of the Albertine graben, principally its oil reserves. It attempts to settle the stratigraphic problems within this part of the EARS with the aim of evaluating its petroleum potential. From previous reports, several formal lithostratigraphic names can be seen. However, it is hard to tell how these differ internally. During this study, a lithofacies approach was employed to look at exposed sections at a higher resolution than just recognizing formations. This approach proved flexible in studying sedimentation in fluvial dominated, tectonically controlled system with abrupt lithofacies changes. Using a combination of field surveying and section measurements, X-Ray diffraction measurements, organic, major and trace element geochemistry, it was possible to designate exposed strata into lithofacies and characterize stratigraphic intervals using the defined facies, depict presence of petroleum source somewhere in the basin, deduce sedimentary environments and tectonic events that have occurred within the basin. Results from this study have shown that rift-fill sediments in the southeast Lake Edward basin are dominated by alluvial fans and fluvial distributary fan complexes. Five individual fan complexes can be recognized fringing the edge of the rift and these merge distally towards the present day lake shoreline. Within the fan complexes, five broad Lithofacies can be recognised. All these fall under two formations i.e. Bwambara and Queen Elizabeth. Potential source, reservoir and seal intervals can be identified within these fan complexes and sequences from outcrop studies. The ongoing petroleum exploration has also produced the first confirmed occurrence of relict oil in porous tufa limestones and on the surface of Lake Edward indicating presence of a working petroleum kitchen some where in the basin. Structurally, the studied part of the basin is dominated by down-to-the east normal faults controlled by basin bounding faults to the east and west (DRC).
Landslide occurrences in the hilly areas of Bududa District in Eastern Uganda and their causes

(Makerere University, 2010-12) Kitutu, Kimono Mary Goretti

Although on a global scale Uganda is not known for landslide disasters, in the recent past especially in the years with above normal rainfall the loss of life and property from these disasters is increasing. This study assesses the factors that influence landslide occurrences in Bududa District and their impacts on to the livelihood of the people. Between 1997 and 2004, heavy rains left 48 people dead and ten thousand displaced and landless. The volume of debris from ninty eight landslides was 11 million m3 and this was deposited into rivers and streams. Twenty nine of these landslides dammed rivers resulting in destruction of bridges and roads when the dams broke. The main landslide types are debris slumps which occur on concave slopes where water concentrates. These landslides occur on steep slopes that are plano concave and between slope angles of 140 to 410. Slopes facing north-east are most prone to landslides which coincide with the dominant rainfall direction. The soil types in this area are those conditioned by topography and tropical climate namely Nitisols, Cambisols, Lixisols, Ferralsols, Leptosols, Gleysols, and Acrisols. The texture of the soil in the horizons was significant to the landslide occurrences especially in the western zone. In the eastern zone, soil profile horizon is significant in some of the landslides but in the shallow landslides the slope and the shallow depth which creates a discontinuity between the saprolite and the rock causing water stagnation is the main influence. The knowledge from farmers’ is almost similar to scientific observations. Farmers mentioned steep slopes, areas with concavities and those with flow of water from underground as areas prone to landslides. Although their observations have a limitation in that they cannot determine the threshold. The soils contain medium to high plasticity clays and according to the Atterberg limits they approximately fall in the categories of kaolinite and illite. The top soils also have a high infiltration rate which allows fast flow of water into the deeper clay rich horizons promoting water stagnation causing slope failure. The main triggering factor is rainfall and rainfall events of low intensity but prolonged for days are thought to be more disastrous however, this is an area that needs further investigation. Terraces are not popular among farmers in some of the areas because they believe that terraces promote water infiltration which triggers landslides. Using the LAPSUS-LS landslide model the slopes in Bududa District are identified as inherently unstable and the volumes of soil redistribution can yield four times higher than what was observed in 1997 (44,000,000 m3). These will end up in stream channels possibly damming rivers and causing damage to infrastructure or siltation and pollution of streams.
Phytogenetic analysis by 16s rRNA gene sequence of a protease-secreting thermophilic bacterial isolate KITNT-3 from Kiteezi landfill

(Makerere University, 2011-07) Nabachwa, Rita

A thermophilic protease-secreting bacterial isolate KITNT-3 from Kiteezi landfill was characterized phylogenetically by determining its relationship with other existing known bacterial strains. Genomic DNA was isolated from the cells and the 16S rRNA gene amplified using universal primers. The amplified PCR product was purified using an elaborate ethanol/EDTA precipitation method and subjected to sequence analysis using an ABI 3130XL genetic analyzer. In order to determine the phylogenetic position of the isolate, the partial 16S rRNA gene sequence was compared with other known 16S rRNA gene sequences of related taxa from the GenBank. A phylogenetic tree was constructed using the MEGA v4 program. The analysis showed that the isolate clusters with members of the genus Bacillus and was closest to Bacillus thuringiensis strain T13001 (ACNC01000278), sharing 99.8 % nucleotide sequence similarity. The crude enzyme was obtained from the culture filtrate of the isolate after an overnight incubation at 550C in a shaking incubator at 80 rpm and the extract was characterized for its caseinolytic activity. The morphological and growth characteristics showed that isolate KITNT-3 is an aerobic, Gram-positive, endospore-forming, thermophile with rod-shaped cells measuring 3.2 µm in length and 0.8 µm in width respectively. The crude enzyme was found to exhibit a specific caseinolytic activity of 0.0065 µmoles tyrosine equivalents/min/mg protein at optimal assay conditions of pH 6 and temperature of 550C. Further purification and characterization of the crude enzyme solution is deemed necessary for a comprehensive enzyme classification.
On algebraic and topological properties of continuous functions over a compact Hausdorff space

(Makerere University, 2011-10) Kurama, Onesfole

For a compact Hausdor topological space, we shall consider a space of all continuous real-valued functions. The central problem of this dissertation is to translate algebraic properties of this collection of functions into topological properties of the underlaying topological space. This involves considering the function space as a ring. One of the major facts is that this function ring is completely determined by the underlaying topological space. This is a result by Leonard Gillman and Meyer Jerison. Therefore we need to specify conditions under which, conversely the topological space can be determined by the algebraic structure of the function space. The topological aspect requires us to specify the collection of subsets that allow us to consider the function space as a topological space with the compact-open topology. The fact that we have enough points to work with is facilitated by Urysohn's Lemma. A more critical investigation that leads us to dense subsets of the function space is developed and facilitated by Stone-Weierstrasss theorem. We narrow down our discussion by considering a unit closed interval as a compact space.
Modelling the severity of dual and co-Infection with malaria in populations with persistent and re-emerging Infections.

(Makerere University, 2011-11) Nannyonga, Betty

Mathematical models have contributed to epidemiological understanding of infectious diseases at all levels, from projections of the magnitude of disease epidemics to the within-host interactions between pathogens and the host’s immune system. The research whose results are outlined in this thesis provide a novel insight into single host-multi pathogen interactions. It constitutes an extensive infectious disease interaction framework constructed for the pathogens and their human and/or vector hosts. Mathematical models in form of coupled differential equations are formulated based on the epidemiology of the interacting species and the transmitting vectors. In some of the studied examples, rather than using differential equations, more recent complex models where stochasticity influences the dynamics and computer simulation needs to be used to generate theory. In each of the study chapters, a specific modelling approach or set of techniques are designed to capture important biological factors of interest to the pathogen under consideration. Particular attention is given throughout the thesis to the development of practical models that are useful both as predictive tools and as a means to understand fundamental epidemiological processes. Diseases considered include malaria, HIV/AIDS, trypanosomiasis (sleeping sickness), Hepatitis E and visceral helminthiasis. Mathematical models describing the dynamics of these diseases when co-infecting with malaria are designed and analyzed. The model for malaria and HIV/AIDS co-infection was designed with HIV-positive immigration and dual protection. Analysis shows that there is no disease-free equilibrium point. Instead, an initial state of infection governed by the infective immigration rate ε exists. A small perturbation around this point approaches global stability if individuals infected with malaria protect themselves against HIV/AIDS during the episode, and if HIV infectives are protected against malaria. Numerical simulation shows that if the prevalence of malaria is high, individuals protect themselves against the disease more than when it is low. In contrast, HIV/AIDS individuals tend not to use protection when there is increased risk of disease transmission. From the model, it is concluded that HIV positive immigrants increase the number of secondary infections as well as the influx of co-infections. In the co-infection of malaria and trypanosomiasis, two mathematical models with and without isolation are formulated. Analysis shows that with strict isolation, the disease-free equilibrium (DFE) is locally asymptotically stable if R0 < 1, and unstable if R0 > 1, but not globally asymptotically stable. Further analysis of the model shows that an endemic equilibrium point exits but not unique due to existence of multiple equilibria of malaria-only, trypanosomiasis-only, or co-existence. Numerical simulation shows that the model exhibits bifurcations and thus cannot attain global stability. When one disease is controlled, results show that the other disease remains endemic in the population where local and global stability are attained under a specific parameter space. In the study of malaria and Hepatitis E, results show that a Hepatitis E outbreak persists in vi presence of malaria. Data was used to determine that R0 for the outbreak was approximately 2. Secondly, the critical level of latrine and borehole coverages needed to eradicate the epidemic was at least 16% and 17% respectively. Results further showed that individuals with malaria were 3.4 more likely to acquire malaria than those without. The critical value of ξ determined in this study agrees with prior studies showing increased susceptibility to other infections for malaria infected individuals [20]. However, this result is speculative and the more important point is the relationship given in Figures 5.4 and 5.6 between co-infection and other model parameters. Immune stimulation and impairment in presence of prophylaxis when malaria and visceral helminthiasis are co-infecting is studied. In absence of immune response, it is found that there is no disease-free equilibrium point, and the antigens invade the blood system if the rate of red cell rupture per invading merozoite is greater than one. If fewer merozoites are released, the initial state of infection is globally asymptotically stable. If more merozoites are released, there exists malaria-only endemic equilibrium point. However, both antigens co-exist if the mean infection burden is greater than one. In this case, there is a threshold value for drug action below which no recovery of host is expected. In presence of immune response, three equilibrium states exist. A model for severity of the co-infection shows that an immune response will be delayed until immunological barrier values for malaria and helminths are exceeded. It is concluded from analytical results that whether the co-infection is sub clinical, acute, chronic or lethal depends on the dose of infection and time taken for immune response. Protection against mosquitoes limits the number of bites by the mosquito per human. In this thesis, a mathematical model where mosquito bites are reduced through DDT house spray was designed. Analysis shows a significant reduction in malaria prevalence. As more people spray, more mosquito are kept away leading to low disease prevalence, and the overall size of the pandemic. If another disease invades the population, the intensity is kept low and co-infections minimal. The main conclusion is that DDT reduces mosquito bites, but consistent house spraying is desirable for the eradication of malaria. One of the greatest effects of malaria is the contribution to high child mortality rates. In this thesis, the effects of how high child mortality rates affect social and economical development are analyzed. The objective is to show that high malaria rates not only kill millions of people each year but have secondary effects as well. A dynamical systems approach was used and it was shown that high child mortality rates lead to high fertility rates and low output per capita. With increasing economic growth, both rates are reduced. The economy then takes off to a sustained growth steady-state equilibrium where child mortality and fertility rates are considerably very low.
Gravity and magnetic data analysis to detect the origin of carbon dioxide in Semliki Basin, Albertine Graben

(Makerere University, 2011-12) Ojangole, George Francis

Semliki basin is one of the most prospecting basins for Petroleum exploration in Uganda. An exploratory well (Turaco-3) drilled to the depth of 2960 m by Heritage Oil and Gas Limited in the Semliki Basin encountered a hydrocarbon-bearing formation, which was found to be heavily contaminated by carbon dioxide (CO2), however, the origin of CO2 is unclear. In order to investigate the origin of CO2, gravity and magnetic data was used in this study to: (a) define the geometry/shape of the gravity and magnetic source bodies by delineating their edges. (b) estimate the depths to the gravity and/or magnetic source bodies in the study area and (c) to integrate the model results with the qualitative analysis of the potential field signals from the subsurface sources in order to establish the origin of the CO2. Regional- residual separation to enhance the local changes in the potential field was done by applying Band pass filter, analytical signal, tilt derivative and horizontal gradient. Euler Deconvolution was then used to define the basement faults and fractures. The results provided new insights into the gravity and magnetic anomalies of the southern part of Lake Albert and the Semliki basin. Some prominent magnetic anomaly trends were observed, namely NE-SW, E-W and NW-SE. The positive correlation between these anomalies and fault trends is an indication that the observed magnetic anomalies and their associated subsurface sources are fault controlled. The faults consequently would play a significant role in the movement of subsurface fluids across the region. The presence of very high amplitude magnetic anomalies and the values of their respective estimated magnetic susceptibilities are considered to support the possibility of magmatic intrusions existing within the Semliki basin, these could be the source of CO2 in the Basin, and migrates through faults. The Rwebisengo anomaly in particular has very high significant association with subsurface structuring and the high amplitudes associated with these anomalies are a good indication of their correlation with magmatic sources in the subsurface. The models further indicate that the sources could be within 3 km depth and shallower.
Distribution solutions to ordinary differential equations with polynomial coefficients on the real line

(Makerere University, 2012-04) Mirumbe, Geoffrey Ismail

In this study we consider the Weyl algebra A1(C) that consists of differential operators P of the form P = pm(x)"m + pm−1(x)"m−1 + . . . + p1(x)" + p0(x), (1) where {p"(x)} are polynomials which in general may have complex coefficients and " is the first order derivation operator with respect to x. To the differential operator P in (1), we associate a differential equation, P(μ) = 0 where μ is either an analytic or a non-analytic function. If the leading polynomial pm(x) has no zeros on the real line (elliptic case) then Cauchy’s result gives m classical solutions. Otherwise, in the non-elliptic case, we have to take into account solutions that are generalized functions (distributions). Our main interest is to establish the dimension of the vector space of the distributional solutions. In this case, we assume that pm(x) has a finite number of real zeros with finite multiplicities and with the degree at most k i.e in the range 1 $ k $ m. With this setting, we will assume that we can re-arrange the corresponding P such that it is locally Fuchsian at each real zero a" of pm(x) withmultiplicitye" ! 1. To each such locally Fuchsian P, we demonstrate the existence of distribution solutions by use of particular cases of P. We state and prove a theorem relating the order of the operator P, the multiplicities of the real zero and the dimension of the P-kernel on the space of distributions Db. Furtherwe prove that for eachreal zero a" of pm(x) there exists a distribution μ supported by the half-line {x ! a"} such that the distribution P(μ) is the Dirac measure at a". Such a μ is called a fundamental solution, and may be used to give a general solution of the differential equation P(μ) = f where f can be either a real analytic function or a generalized function. We also use the theory of boundary values (boundary value distributions) and the Cauchy transform of distributions with compact support to prove coexistence of solutions in the form of the finite order linear combination of the Dirac delta function and its derivatives and rational function solutions to ordinary differential equations with polynomial coefficients.
Heavy metal and nutrient loading of river Rwizi by effluents from Mbarara municipality, western Uganda

(Makerere University, 2012-09) Egor, Moses

The rapid expansion of Mbarara town in Western Uganda has significantly elevated its anthropogenic pollution over the recent past. It is feared that the increasing volume of untreated effluent discharge might find its way into the sources of domestic water. This study, carried out in the wet April annual seasons during the period 2010-2011, was geared towards the quantification of heavy metal and nutrient levels in the surface water of River Rwizi, the main Mbarara Municipal drainage system. These times were chosen primarily due to frequent torrential runoffs from the township area and increased total volumes of effluent and leachates. In this study, the effect of Mbarara municipal effluents on heavy metal and nutrient (phosphate, nitrite, nitrate and ammonium) loading of river Rwizi was investigated along with the changes in some basic water quality parameters, i.e., pH, conductivity and hardness. Heavy metals, especially cadmium and lead, pose serious health risks to humans. The filtered water samples were digested with a perchloric acid/nitric acid/hydrochloric acid mixture. Total heavy metals Cu, Zn, Cd and Pb were determined by flame atomic absorption spectrophotometry. Results showed that there was a significant difference (F = 4.369, DF = 11, p = 0.047) in concentration of lead in 2010 and (F = 7.105, DF = 11, p = 0.014) in 2011 along River Rwizi around Mbarara Municipality, the concentration being higher downstream. Average concentration of 1.302 μg ml-1 upstream, 0.807 μg ml-1 in the town area and 1.608 μg ml-1 downstream which showed an average increase in lead downstream. There was also a significant difference (H = 8.00, DF = 2, p = 0.018) in 2010 and 2011 (F = 41.024, DF = 11, p= 0.000), in concentration of zinc in River Rwizi water before and after Mbarara town, with average concentration being higher downstream. The higher metal concentration downstream more likely is a result of loading from the town. The concentrations of lead and cadmium were much higher than the WHO guideline values in drinking water (0.01 μg ml-1 and 0.003 μg ml-1 respectively); indicating that ingestion of raw water from this river could expose one to the harmful effects of the two metals. The concentration of Cu upstream, mid-town and downstream for 2010 and 2011 were compared using Kruskal-Wallis test, which showed a significant difference (H = 9.33, DF = 2, p = 0.009) in 2010 and (H = 8.80, DF = 2, p = 0.012) in 2011. There was a slight increase in concentration going downstream with average concentrations of 0.043 μg ml-1, 0.069 μg ml-1 and 0.15 μg ml-1 going downstream. This is clearly a contribution from the town. There was no significant difference in concentration of Cadmium in 2010 along river Rwizi around Mbarara town (H = 3.43, DF = 2, p = 0.180). The average Cd concentration in most samples was 0.029 μg ml-1. However, the concentration of Cd was higher than the WHO guideline value in drinking water (0.003 μg ml-1), which poses a threat to living organisms using this water directly. Although the Zn and Cu levels were still below the maximum tolerable levels (MTL) of 3.0 Zn and 2.0 Cu laid down by the World Health Organisation (WHO), those of Cd and Pb are higher (0.029 μg ml-1 Cd and 1.608 μg ml-1 Pb against WHO MTL values of 0.003 Cd and 0.01 μg ml-1 Pb). Nutrient loading in the domestic water source is also on the increase. Results indicate a gradual annual increase in these levels and call for early pollution control measures by the relevant authorities. Phosphate was the most predominant of the nutrients considered, followed by nitrates and fluctuating low amounts of ammonium and nitrite nutrients. Most nitrogen in River Rwizi water occurs as nitrates, whose concentration also increased downstream throughout the sampling period, giving no significant concentration difference in the sampling sites in 2010 (F = 3.843, DF = 11, p = 0.062) and a significant difference in 2011 (H = 7.65, DF = 2 p = 0.022). There was also a slight increase in nitrate levels in 2011 (0.233-0.577 µg ml-1) as compared to 2010 (0.119-0.54µg ml-1).
Synthesis and characterisation of selected polyoxometallates and their applications in catalysis

(Makerere University, 2012-10) Tebandeke, Emmanuel

Green processing is a central issue in both academia and industry, with regard to chemical synthesis because without this approach, industrial chemistry is not sustainable. Chemists are proud of their ability to create highly valuable compounds from inexpensive raw materials. In this thesis is presented green processing methods that were developed in the present study. Highly efficient green processes for the epoxidation of olefins using molecular oxygen and hydrogen peroxide oxidants, catalysed by nanogold and silver catalysts supported on salts of polyoxometallate anions (POMs) are presented. These nanoparticles were stabilized in solution by the POMs and eventually supported onto their salts. The optimized supported catalysts were employed in the epoxidation of olefins using the above green oxidants. The gold catalysts supported on POMs are efficient in the epoxidation of olefins with air or pure dioxygen oxidant in the presence or absence of a solvent at 353 K. The method enjoys high conversions and selectivity, with no sacrificial reductants or promoters needed. For example, cyclooctene and 2-norbonene could be epoxidized with > 95% selectivity to the corresponding epoxides. The silver catalysts supported on POMs are remarkably efficient in the epoxidation of olefins with hydrogen peroxide oxidant with or without a solvent at 333 K. The method enjoys >90% conversion and =99% selectivity to the epoxide for a variety of olefins. In both cases the catalysts are easily recovered by filtration and are reusable several times. But the supported silver catalyst should be preferred from the economic point of view. Methods for CO2 coupling with epoxides to produce cyclic carbonates are also presented. Various transition metal substituted POMs (TMSPs) in conjuction with di-methyl amino pyridine (DMAP) base co-catalyst were found to be quite effective in the coupling of CO2 with propylene oxide to form propylene carbonates at a CO2 pressure of 30 bars and 140OC. In addition, tetraalkylammonium salts of TMSPs were investigated for the coupling of epoxides with CO2 in the absence of DMAP. A number of these catalysts produced the cyclic carbonates in good yields and selectivity. For example, when using [(C7H15)4N]8ZnW11O39Co catalyst, the system enjoys >95% conversion and >96% selectivity to the corresponding cyclic carbonate for a variety of epoxides. Results of this study also showed that the catalytic activity is significantly influenced by the type of addenda transition metal and the counter ion. For example, cobolt- and manganese- substituted POMs showed higher activity whereas the copper one showed low activity. A binary catalyst system composed of Ag/AgPOM and n-tetra butyl ammonium bromide (TBAB) was used in the direct synthesis of cyclic carbonates from olefins and CO2 using 50% H2O2 as an oxidant in the presence of a base. This system produced the corresponding cyclic carbonates with >90% conversion and high selectivity to the cyclic carbonates for a variety of olefins. Results of this study also showed that both POM and TBAB were necessary for the reaction and no cyclic carbonate was formed without either catalyst or base co-catalyst. Further, these catalysts could be reused without loss of activity and selectivity.
Relative suitability of phosphorus analytical methods for a ferralsol

(Makerere University, 2012-11) Odama, Emmanuel

Declining soil fertility is a fundamental impediment to agricultural growth and a major reason for the slow growth in food production in sub-Saharan Africa. Among the primary plant macronutrients, phosphorus is the most important nutrient element, limiting agricultural production. In order to manage soil phosphorus objectively, the existing stocks in the soil should be known. It is on this basis that informed effective recommendations for intervention can be made. However, among the challenges in achieving reliable information lies the use of the most efficient analytical methods that simulate closely with plant nutrient uptake and growth. The most widely used soil P extractants are Bray I, Bray II, Olsen, Mehlich I, II and III. These methods were largely developed targeting temperate soils and eventually extended for use under tropical soils without the necessary evaluation for relative effectiveness and efficiency. This study was, thus, geared to evaluating the common methods of testing for soil available P in laboratories in Uganda so as to identify the most appropriate method. Treatments administered included six P rates namely, 0 (Control), 20, 40, 60, 80 and 100 kg P ha-1. Three soil phosphorus extraction methods used included Bray I, Bray II and Mehlich III. The experiment was set in a greenhouse at Abi Zonal Agricultural Research and Development Institute, Arua, Uganda. Maize variety Longe V was used as the test crop. Data collected were analysed with the GenStat software, and correlations were run between available P fractions extracted using the different methods against dry matter and plant growth parameters. Mehlich III presented the highest correlation coefficient with stem girth (r = 0.63), number of leaves (r = 0.733) and plant P (r = 0.254). There was a strong positive correlation between Bray I and Mehlich III methods (r = 0.975), thus either could be used to quantify extractable P in Ferralsols with mica, kaolinite and quartz mineralogy of 1.57% organic carbon and pH 5.6.
Rock bed thermal energy storage for solar cooking application (Potential for solar cooking in Uganda)

( 2012-11) Okello, Denis

This thesis focus on the development of a rock bed heat storage for storing solar energy for cooking and other applications requiring heat in the range of 1000C to 3500C. The potential of using such a system in Uganda is evaluated and it is observed that the northern part of the country has a promising potential for small domestic systems as well as for other large scale solar industrial applications. The thermal performance of an air-rock based system is investigated experimentally and theoretically using the modified Schumann's one-dimensional energy balance equation. The effects of inlet temperature, air flow rate, particle size on the charging behaviour of the rock storage were investigated. Increasing the bed inlet temperature increases the energy content of the bed but the temperature profile along the bed is similar. Result of varying air flow rate indicates faster bed charging with increased air flow. More stratification occurs with smaller sized particles. The degradation of higher temperature at the bed top with storage time was investigated and it was observed that faster loss in stratification occurred in a highly stratified bed compared to a bed with is almost fully charged. The variation of pressure drop for different rocks sizes with air flow rates is investigated and the experimental results were compared with different pressure drop correlations reported in literature. A strong dependence of pressure drop on air mass flow rates and particle sizes was observed and comparison with other pressure drop results showed the Dunkle's correlation predicting slightly higher values compared to experimental results in all experimental runs. The discharging of a heat bed of rocks was performed by reversing the air flow direction through the bed. The test results showed that faster cooking rate can be achieved using a rock stove and this rate can be control by simply adjusting the air flow speed through the bed. And finally, the energy content of the bed can be enhanced by incorporating phase change materials in a bed of rocks.

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