Browsing by Author "Nsubuga, Denis"

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    Characterization of briquettes developed from banana peels, pineapple peels and water hyacinth
    (Research Square, 2022) Mibulo, Tadeo; Nsubuga, Denis; Kabenge, Isa; Wydra, Kerstin D.
    Uganda's energy needs are heavily reliant on biomass sources. This dependency of Uganda's burgeoning population on biomass for household and commercial purposes is posing pressure on natural resources such as forests. This study was carried out to investigate the utilization of some of the country's highly produced agricultural waste for the creation of biofuels. Methods: Pineapple peels, banana peels and water hyacinth were utilized for generation of both carbonized and uncarbonized briquettes. Physical properties and calorific values for the developed briquettes were determined through thermogravimetric analysis and using a bomb calorimeter. Results and conclusion: Pineapple peel carbonized briquettes had the highest calorific value (25.08 MJ/kg) followed by a composite of banana peels and pineapple peels (22.77 MJ/kg). The moisture content for briquettes ranged between 3.9 to 18.65%. Uncarbonized briquettes had higher volatile matter (ranging between 62.83 and 75.1%) than carbonized briquettes (ranging between 22.01 and 24.74%). Uncarbonized briquettes had shorter boiling time (ranging between 27 and 36 minutes for 2.5 liters) than carbonized briquettes (ranging between 26 and 41 minutes). Water hyacinth alone produced briquettes with low calorific values (16.22 MJ/kg), however, calorific values increased when mixed with banana (20.79 MJ/kg) or pineapple peels (20.55 MJ/kg). The findings reveal crucial information on how agricultural wastes might be used to augment the energy sources pool in order to protect the environment and creating social stability in the community.
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    Contrasting Impact of Rural, Versus Urban, Living on Glucose Metabolism and Blood Pressure in Uganda
    (Wellcome open research, 2020) Sanya, Richard E.; Biraro, Irene Andia; Nampijja, Margaret; Zziwa, Christopher; Nanyunja, Carol; Nsubuga, Denis; Kiwanuka, Samuel; Tumusiime, Josephine; Walusimbi, Bridgious; Cose, Stephen; Ocama, Ponsiano; Grencis, Richard K.; Elliott, Alison M.; Webb, Emily L.
    The burden of cardiometabolic diseases, including cardiovascular diseases and diabetes, is increasing in sub-Saharan Africa and this has been linked to urbanisation. Helminths, through their immunomodulatory properties, may protect against these disorders. We hypothesised that the rural environment protects against cardiometabolic diseases and that helminths may influence rural-urban disparity of cardiometabolic disease risk.We compared metabolic parameters of individuals aged ≥10 years living in rural, high-helminth-transmission and urban, lower-helminth-transmission settings in Uganda. Cross-sectional surveys were conducted in rural Lake Victoria island fishing communities and in urban sub-wards in Entebbe municipality. Helminth infection and outcomes, including insulin resistance (computed using the homeostatic model assessment of insulin resistance [HOMA-IR]), fasting blood glucose, fasting blood lipids, blood pressure, body mass index (BMI), waist and hip circumference, were assessed.We analysed 1,898 rural and 930 urban participants. Adjusting for BMI, exercise, smoking, alcohol intake, age and sex, urban residents had lower mean fasting glucose (adjusted mean difference [95%CI] 0.18 [-0.32, -0.05] p=0.01) and HOMA-IR (-0.26 [-0.40, -0.11] p=0.001) but higher blood pressure (systolic, 5.45 [3.75, 7.15] p<0.001; diastolic, 1.93 [0.57, 3.29] p=0.006). Current helminth infection did not explain the observed differences.In the Ugandan context, living in rural fishing communities may protect against hypertension but worsen glucose metabolism.
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    Innovations in Value-Addition of Agricultural By-Products in Uganda
    (Journal of Environmental Protection, 2019) Nsubuga, Denis; Banadda, Noble; Kiggundu, Nicholas
    The purpose of this review was to profile the existing innovations in the value addition of agricultural by-products and suggest innovations that could yield more value-added products from the available agricultural by-products in Uganda. These by-products were from crops, livestock, fish and forestry sub-sectors. The review indicated 7.8 million tons from the crops’ subsector, 6.69 million skins and hides, 2280 million tons of cow dung and 390,550 tons of chicken dung from the livestock subsector, 36,000 tons from the fish subsector and 440,000 m3 of sawdust and offcuts from the forestry sub-sector. Current innovations in value-addition of agricultural by-products included the making of briquettes, organic fertilizers, biogas, biochar, pellets and organic pesticides from the crop subsector. Cow dung from the livestock is used for plastering walls of houses, used as fertilizer and used for the production of biogas. Chicken droppings are as well used as fertilizer and for production of biogas. Fish frames and skins are mainly consumed in smoked form whereas trimmings are usually rolled into fish balls and then fried for people to eat while the fats are used for frying the fish balls. Sawdust has been mixed with cement to make wood-cement composite bricks that reduce the overall weight of the building. It is also being used as feed in the Indigenous Micro-Organisms (IMO) technology in the production of pigs. Proposed innovations include the use of bones to produce soft tissue, buttons, knife handles and bone meal. Blood can be used in making adhesives and fertilizers while fish oil is a major dietary source of long chain omega-3 polyunsaturated fatty acids and so can be utilized to enrich different food products.
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    Performance Evaluation and Optimization of the Maize Shelling Operation of the Multi-Purpose Farm Vehicle
    (CIGR Journal, 2020) Nsubuga, Denis; Kabenge, Isa; Zziwa, Ahamada; Kiggundu, Nicholas; Wanyama, Joshua; Banadda, Noble
    Small-scale farmers register high postharvest losses partly due to failure to carry out primary processing operations. Most of the maize shellers on the Ugandan market lead to high percentage of broken maize grains thus raising the risk of aflatoxin infection during storage. In this study, the operation of an existing maize sheller on the market with a shelling speed of 870 rpm for maize at 13 % moisture content was tested. The main objective of this study therefore was twofold; (i) to develop and evaluate a maize sheller and (ii) to optimize the multi-purpose vehicle shelling operation. The improved maize sheller was designed, fabricated, evaluated and optimized using a factorial experiment with shelling speed and moisture content as the main effects at three levels. Analysis of Variance was done using R-studio. A cost-benefit analysis of the shelling technology was conducted. The obtained results showed that a reduction in moisture content and an increase in shelling speed increased the shelling efficiency, the grain damage percentage, output capacity and the cleaning efficiency. The optimum moisture content and the shelling speed of the multi-purpose vehicle maize shelling were 13% and 896 rpm respectively. Except the shelling efficiency, the results of the modified maize sheller were significantly different (p<0.05) from those of the market sheller. The payback period was 1.37 years while the benefit-cost ratio was 1.07. The optimized maize shelling operation of the multi-purpose vehicle is therefore economically viable.
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    Potential of Jackfruit Waste as Anaerobic Digestion and Slow Pyrolysis Feedstock
    (Journal of Biosystems Engineering, 2021) Nsubuga, Denis; Banadda, Noble; Kabenge, Isa; Wydra, Kerstin D.
    The estimated annual worldwide production of jackfruit peelings (JP) and jackfruit seeds is 2.96 million tonnes. This study assesses the suitability of this jackfruit waste from soft and firm jackfruit varieties as potential feedstocks for anaerobic digestion and slow pyrolysis.Proximate, ultimate, calorific values, thermogravimetric, compositional and lignocellulosic analyses were conducted.The volatile matter, fixed carbon, hydrogen and carbon content of soft and firm jackfruit waste (peelings and seeds) ranged between 76.81 and 78.83%, 18.28 and 19.42%, 5.43 and 7.13% and 43.89 and 48.08%, respectively. The higher heating values (HHV) of soft and firm jackfruit waste ranged between 17.42 and 19.81 MJ/kg. The ash content of jackfruit waste from both varieties varied within the recommended range of less than 8%. The starch content of jackfruit peelings and seeds from both soft and firm varieties ranged between 29.05 and 59.54% while the sugar content of jackfruit peelings and seeds from soft and firm varieties ranged from 2.04 to 68.8%. The maximum weight degradation rate for the jackfruit waste for both jackfruit varieties occurred in the temperature range of 450–550 °C which is within the slow pyrolysis regime. Generally, cellulose formed the biggest proportions of the lignocellulosic composition followed by hemicellulose and lignin.Jackfruit waste from both soft and firm varieties is a potential feed stock for slow pyrolysis while soft variety jackfruit waste is more suitable for biogas production compared to the firm jackfruit wastes.
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    Potential of Jackfruit Waste for Biogas, Briquettes and as a Carbondioxide Sink-A Review
    (Journal of Sustainable Developmen, 2020) Nsubuga, Denis; Banadda, Noble; Kabenge, Isa; Wydra, Kerstin D.
    One of the key aspects of a green economic development model of a country is to develop indigenous resources and local expertise while utilizing sustainable technologies. This review explored the possibilities of utilizing jackfruit waste for production of biogas, briquettes and biochar. In many of the developing countries, there is huge potential for organic waste conversion into appropriate energy solutions. These can contribute to developing rural areas especially small holder farmers and diversifying the available energy sources. Biomass waste like jackfruit waste when managed well can produce bio-energy, but also the GHG emissions need to be reduced from unmanaged, decomposing organic material. When put to use, agricultural biowastes like jackfruit waste could be used as raw materials in the production of bio-products (biofuels, biochar, bio pesticides), briquettes, among others. The biochar can be mixed with the soil producing carbon-rich soils and contribute to CO2 sequestration and soil fertility. This paper reviews works focused on using jackfruit waste for anaerobically producing of biogas, briquettes and biochar for improved crop production. The paper concluded that jackfruit waste can anaerobically decompose to produce biogas and it can also be used for briquette production. It was further concluded that jackfruit waste can undergo decomposition at high temperatures to produce biochar which can be incorporated into the soil creating a CO2 sink hence helping in mitigating the effects of the climate change.