School of Engineering (SEng.) Collections
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ItemAssessing the potential for the use of reinforced masonry as an alternative to reinforced concrete lintels in building construction(Makerere University, 2024)This study focuses on the experimental and numerical comparison of the flexural behavior of concrete beams and masonry beams. Different specimens for the construction of lintels with concrete block masonry have been tested for comparison with their reinforced concrete counterparts. Reinforced masonry beams with three hollow cell concrete blocks and with steel reinforcement have been built and tested in a three-point loading test configuration. Numerical modeling of the masonry beams was then performed using Abaqus software, based on the Finite Element Method, and compared with experimental results to validate the simulation, this was followed by a parametric study of masonry beams to better understand their flexural behaviour. Span-to-depth ratios and reinforcement ratios are the main parameters analyzed in this study. In conclusion, it was verified that the span to depth ratio and reinforcement ration greatly affect flexural behaviour of masonry beams. It was clear that horizontal bed joint reinforcement increases the flexure strength of masonry beams. However, the masonry beams showed lower ductility than the reinforced concrete beams under similar loading and span conditions. It was also noted that a deeper analysis should be made regarding the would-be effect of vertical reinforcement on the global flexural behavior of the masonry beams.
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ItemEvaluation of the potential of anaerobic co-digestion of scum produced from settling-thickening tanks with faecal sludge(Makerere University, 2022)Poor hygiene and sanitation is a major public health concern mainly due to lack of proper method of disposal of faecal sludge. However, Lubigi combined wastewater and faecal treatment plant has attempted to provide safe disposal measures of faecal sludge with use of settling thickening tanks of an effective volume of 1250m3 to separate the solids and liquids in the faecal sludge. In the tank, faecal sludge settles at the bottom while the scum accumulates at a rate of 0.033m3/m3.day per faecal sludge inflow at the top. This project attempts to characterise the scum and faecal sludge formed, to evaluate the biogas potential of the scum and faecal sludge and to determine the quality of the slurry produced. In this regard, samples of faecal sludge and scum were picked from Lubigi combined wastewater and faecal treatment plant and analysed for total solids (TS), total volatile solids (TVS), BOD5, COD, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), lipid content, pH and E coli. Biomethane potential experiments with and without pH adjustment were also run at 5 different volatile solids concentration: faecal sludge and scum ratios of 1:0, 4:1, 3:1, 1.5:1, 0:1. Each bottle was added with 80mL of seeding sludge picked from the Nakivubo biogas reactors. Alkalinity, volatile fatty acids, pH and ammonia were monitored while running the experiments. Scum quality parameters obtained were as follows: TS; 198010-263986.6mg/L, TVS; 42.30 64.68%TS, BOD; 5000mg/L, COD; 100000-148400mg/L, E. coli; 3.16x105- 1,73x107, TN; 0.97%, lipid content; 11.45% of dry matter, TP; 2006mg/L, pH 8.65-8.88. While the faecal sludge quality parameters gave the following results: TS; 117890-210993.33mg/L, TVS; 55.48-62.63 %TS, BOD; 3400-3900mg/L, COD; 88000-122000mg/L, E. coli; 555.56- 1.76x105, TN; 0.61-0.79, TP; 620-1368mg/L, pH 8.37-8.43. Before adjusting the pH, the biogas accumulated per grams of volatile solids were as follows: (inoculum) ISR 4:1 gave the highest accumulated biogas of 134mL/g VS of scum, followed by ISR of 3:1 with 73.51 mL/g VS of scum and lastly ISR of 1,5:1 with 33 mL/gVS of scum. The scum control reactor produced 4 mL/g VS. Biogas yield increased with a decrease in the scum loading but faecal sludge was not able to produce biogas when scum was not added. With pH adjustment, the gas produced increased by 145% for ISR 4:1. For ISR 1.5:1, the gas produced increased by over 200%. For the FS control, the gas produced increased from 0 to 166.5 mL. For the scum control, gas production increased by 54%. However, this trend wasn’t the same for ISR 3:1, which needs to be proven by further experiments.
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ItemLifecycle assessment of polyethylene terephthalate plastic recycling in Uganda(Makerere University, 2025)This report presents a Life Cycle Assessment (LCA) of polyethylene terephthalate (PET) recycling in Uganda. The environmental impacts associated with each stage of the recycling process are quantified using OpenLCA software. Data collected from a local PET recycling facility was used to carry out this assessment. The assessment focused on key impact categories including global warming potential, eutrophication, and terrestrial eco-toxicity among others. The results were calculated using different methods such as CML IA Baseline and ReCiPe 2016 Method 2016. The GWP was determined to be 6.6169 kg eq and the eutrophication potential was determined 0.00241 kg eq. The results produced indicate that the hot washing stage is the most environmentally intensive due to the use of a diesel- powered steam boiler and other inputs in that process. The highest contributors across all impact categories were found to be the same for example diesel fuel, electricity and sodium hydroxide among others. These findings show the need for cleaner energy sources and better adapted LCA datasets tailored to the Ugandan context. The study recommends further development of the localized inventory datasets that will provide more reliable modeling for enhanced LCA results. This in turn will support sustainable plastic recycling operations in future developments.
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ItemDesign and fabrication of a low-cost pneumatic sheet metal cutting and bending machine(Makerere University, 2025)This project focuses on the design and fabrication of a low-cost pneumatic sheet metal cutting and bending machine suitable for small and medium-scale industries. The machine employs a double-acting pneumatic cylinder controlled by a 220V solenoid valve to automate cutting and bending operations on low to medium thickness sheet metals. The pneumatic system, operating at 6–8 bar pressure, provides rapid, reliable, and precise force application, reducing manual labor and improving productivity. The machine’s compact and portable design allows easy handling and maintenance, while interchangeable punches and dies enable versatility in sheet metal processing. This approach offers an economical alternative to hydraulic systems, emphasizing simplicity, efficiency, and automation to meet industrial demands for quality and speed.
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ItemAn investigation of the health and safety practices at ISSA Auto Garage Limited, Nakawa(Makerere University, 2025)Motor vehicle repair workshops are a key sector in Uganda's economy, yet employees are exposed to extreme occupational health and safety risks. This study aimed to assess the health and safety practices at Issa Auto Garage Limited, to determine hazards, their effects, and determining if the garage was in accordance with HSE practices. A mixed-methods approach was employed, with desk research, questionnaires completed by workshop employees, and interviews with the owner of the garage. Physical risks such as exposure to radiation and vibrations, chemical risks through solvents and fumes, and ergonomic risks through lifting and posture were identified through the research. The impact of these risks included instances of injury, illness, and reduced productivity. Further, the study examined compliance of the garage with Occupational Health and Safety national standards and enforcement of protective practices such as the provision and use of personal protective equipment. The findings of this study are critical to the development of targeted strategies aimed at mitigating occupational hazards, improving the work environment, and enhancing the health, safety, and productivity of mechanics in Issa Auto Garage Limited and, by extension, towards the ultimate goal of a healthy and safe workforce in Uganda's automobile sector.