College of Engineering

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    ANALYSIS OF CONTROLED SELF-EXCITED INDUCTION GENERATOR
    (2023-06-20) OLANIPEKUN AYORINDE JOSEPH
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    NUMERICAL MODELLING OF THE HYDRODYNAMICS, HEAT TRANSPORT AND EVAPORATION OF ALUMINA NANOPARTICLES-BIODIESEL SURROGATE DROPLET
    (2023-10-20) OLAMIDE, OLALEKAN OLAOLUWA
    ABSTRACT Biodiesel is a renewable fuel that can readily replace petrodiesel in internal combustion engines and furnaces. However, it contains less energy density than petrodiesel, which can be enhanced by adding energetic nanoparticles. This study modelled the flow, heat transfer and evaporation characteristics of an isolated biodiesel surrogate (methyl decanoate) droplet containing Al2O3 nanoparticles sedimenting in air. The effects of nanoparticle volume fraction (φ), Reynolds number (Re) and evaporating temperatures in the range 0 to 0.1; 0.1 to 250; and 523 to 723 K, on flow vigour, Nusselt number (Nu), Sherwood number (Sh) and droplet regression, respectively, were investigated. The influence of internal circulation on the modes of heat transfer during non-evaporative heating was also examined with the initial droplet and ambient temperatures of 300 and 400 K, respectively. The problem governing equations, including the continuity, momentum and energy, were discretized and solved using the finite volume method with ANSYS Fluent 18.1 while a MATLAB program was written for implementing the evaporation model. At the domain inlet, outlet, walls and centreline, the Dirichlet, pressure outlet, Neumann and axisymmetric boundary conditions were imposed, respectively. User-defined functions were written in C++ to prescribe the continuity of tangential velocity and shear stress at the liquid-gas interface. A mesh consisting of 151423 nodes was chosen for the simulation after conducting a grid independence test. The validations of the drag, heat transfer and evaporation rates were in good agreement (±10%) with the experimental and numerical data obtained from literature for Re up to 100. The droplet's internal flow structure was similar to the Hill’s vortex for all Reynolds numbers. At critical Reynolds number, Re = 23.29, lung-shaped vortices were formed behind the droplet and grew in size with the increase in Re. At Re of 0.1, the isotherms inside the droplet were concentric about its centre, signifying pure diffusion. The isotherms within the droplet transformed from concentric circles at low Re to two deformed cells at high Re. There was an increase in Nu by 8.56 and 110.64%; 15.96 and 41.78% when Re increased from 0.1 to 50 and 250; and φ from 0 to 0.02 and 0.1, respectively. The square of the droplet diameter regressed linearly at a faster rate with the increase in Re than φ, obeying the classical D-squared law during evaporation for all the cases considered. An increase in φ from 0 to 0.04 enhanced the heat transfer during evaporation by 0.24 and 0.30% for Re of 100 and 200, respectively. Sherwood numbers increased with increasing φ for non-isothermal droplet evaporation but did not surpass 0.1%. The reduction in evaporation time for φ of 0.04 and 0.1 at Re of 100 were 1.66 and 1.20% respectively. Heat transfer enhancements were observed with the addition of Al2O3 nanoparticles in methyl decanoate, while the changes in flow and mass transfer characteristics were marginal. The modelling and simulation of the evaporation characteristics of an isolated Al2O3 nanoparticles-biodiesel surrogate droplet showed enhanced performance.
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    NUMERICAL MODELLING OF THE HYDRODYNAMICS, HEAT TRANSPORT AND EVAPORATION OF ALUMINA NANOPARTICLES-BIODIESEL SURROGATE DROPLET
    (2023-10-25) OLAMIDE, OLALEKAN OLAOLUWA
    ABSTRACT Biodiesel is a renewable fuel that can readily replace petrodiesel in internal combustion engines and furnaces. However, it contains less energy density than petrodiesel, which can be enhanced by adding energetic nanoparticles. This study modelled the flow, heat transfer and evaporation characteristics of an isolated biodiesel surrogate (methyl decanoate) droplet containing Al2O3 nanoparticles sedimenting in air. The effects of nanoparticle volume fraction (φ), Reynolds number (Re) and evaporating temperatures in the range 0 to 0.1; 0.1 to 250; and 523 to 723 K, on flow vigour, Nusselt number (Nu), Sherwood number (Sh) and droplet regression, respectively, were investigated. The influence of internal circulation on the modes of heat transfer during non-evaporative heating was also examined with the initial droplet and ambient temperatures of 300 and 400 K, respectively. The problem governing equations, including the continuity, momentum and energy, were discretized and solved using the finite volume method with ANSYS Fluent 18.1 while a MATLAB program was written for implementing the evaporation model. At the domain inlet, outlet, walls and centreline, the Dirichlet, pressure outlet, Neumann and axisymmetric boundary conditions were imposed, respectively. User-defined functions were written in C++ to prescribe the continuity of tangential velocity and shear stress at the liquid-gas interface. A mesh consisting of 151423 nodes was chosen for the simulation after conducting a grid independence test. The validations of the drag, heat transfer and evaporation rates were in good agreement (±10%) with the experimental and numerical data obtained from literature for Re up to 100. The droplet's internal flow structure was similar to the Hill’s vortex for all Reynolds numbers. At critical Reynolds number, Re = 23.29, lung-shaped vortices were formed behind the droplet and grew in size with the increase in Re. At Re of 0.1, the isotherms inside the droplet were concentric about its centre, signifying pure diffusion. The isotherms within the droplet transformed from concentric circles at low Re to two deformed cells at high Re. There was an increase in Nu by 8.56 and 110.64%; 15.96 and 41.78% when Re increased from 0.1 to 50 and 250; and φ from 0 to 0.02 and 0.1, respectively. The square of the droplet diameter regressed linearly at a faster rate with the increase in Re than φ, obeying the classical D-squared law during evaporation for all the cases considered. An increase in φ from 0 to 0.04 enhanced the heat transfer during evaporation by 0.24 and 0.30% for Re of 100 and 200, respectively. Sherwood numbers increased with increasing φ for non-isothermal droplet evaporation but did not surpass 0.1%. The reduction in evaporation time for φ of 0.04 and 0.1 at Re of 100 were 1.66 and 1.20% respectively. Heat transfer enhancements were observed with the addition of Al2O3 nanoparticles in methyl decanoate, while the changes in flow and mass transfer characteristics were marginal. The modelling and simulation of the evaporation characteristics of an isolated Al2O3 nanoparticles-biodiesel surrogate droplet showed enhanced performance.
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    NUMERICAL MODELLING OF THE HYDRODYNAMICS, HEAT TRANSPORT AND EVAPORATION OF ALUMINA NANOPARTICLES-BIODIESEL SURROGATE
    (2023-10-30) OLAMIDE, OLALEKAN OLAOLUWA
    ABSTRACT Biodiesel is a renewable fuel that can readily replace petrodiesel in internal combustion engines and furnaces. However, it contains less energy density than petrodiesel, which can be enhanced by adding energetic nanoparticles. This study modelled the flow, heat transfer and evaporation characteristics of an isolated biodiesel surrogate (methyl decanoate) droplet containing Al 2 O 3 nanoparticles sedimenting in air. The effects of nanoparticle volume fraction (φ), Reynolds number (Re) and evaporating temperatures in the range 0 to 0.1; 0.1 to 250; and 523 to 723 K, on flow vigour, Nusselt number (Nu), Sherwood number (Sh) and droplet regression, respectively, were investigated. The influence of internal circulation on the modes of heat transfer during non-evaporative heating was also examined with the initial droplet and ambient temperatures of 300 and 400 K, respectively. The problem governing equations, including the continuity, momentum and energy, were discretized and solved using the finite volume method with ANSYS Fluent 18.1 while a MATLAB program was written for implementing the evaporation model. At the domain inlet, outlet, walls and centreline, the Dirichlet, pressure outlet, Neumann and axisymmetric boundary conditions were imposed, respectively. User-defined functions were written in C++ to prescribe the continuity of tangential velocity and shear stress at the liquid-gas interface. A mesh consisting of 151423 nodes was chosen for the simulation after conducting a grid independence test. The validations of the drag, heat transfer and evaporation rates were in good agreement (±10%) with the experimental and numerical data obtained from literature for Re up to 100. The droplet's internal flow structure was similar to the Hill’s vortex for all Reynolds numbers. At critical Reynolds number, Re = 23.29, lung-shaped vortices were formed behind the droplet and grew in size with the increase in Re. At Re of 0.1, the isotherms inside the droplet were concentric about its centre, signifying pure diffusion. The isotherms within the droplet transformed from concentric circles at low Re to two deformed cells at high Re. There was an increase in Nu by 8.56 and 110.64%; 15.96 and 41.78% when Re increased from 0.1 to 50 and 250; and φ from 0 to 0.02 and 0.1, respectively. The square of the droplet diameter regressed linearly at a faster rate with the increase in Re than φ, obeying the classical D-squared law during evaporation for all the cases considered. An increase in φ from 0 to 0.04 enhanced the heat transfer during evaporation by 0.24 and 0.30% for Re of 100 and 200, respectively. Sherwood numbers increased with increasing φ for non-isothermal droplet evaporation but did not surpass 0.1%. The reduction in evaporation time for φ of 0.04 and 0.1 at Re of 100 were 1.66 and 1.20% respectively. Heat transfer enhancements were observed with the addition of Al 2 O 3 nanoparticles in methyl decanoate, while the changes in flow and mass transfer characteristics were marginal. The modelling and simulation of the evaporation characteristics of an isolated Al 2 O 3 nanoparticles-biodiesel surrogate droplet showed enhanced performance.
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    INVESTIGATION OF THE POTENTIALS OF SISAL-PALM SLAG COMPOSITES AS MATERIALS FOR ASBESTOS FREE BRAKE PAD
    (2023-12-15) ANIBABA ADEBOLA DANIEL
    ABSTRACT Asbestos are employed in brake pads on account of their good physico-mechanical properties. However, they are now being avoided because of the health challenges associated with their application. This research investigated the potentials of sisal- palm slag composite material for automobile brake pad production. Ten composite brake pads prototypes were produced in varying proportions of sisal (20-30%), palm slag (20-30%), epoxy resin (15-20%), steel dust (15-20%) and silica (10-15%). The composition was formulated based on the output generated from extreme vertices experimental design. Conventional brake pad (CBP) sample was used as control in the study. Key physical and tribo-mechanical properties such as density (ρ), porosity (φ), wear rate (Ŵ), hardness HB and compressive strength (σ) of the produced brake pad and control were determined following recommended standards and procedures. The produced brake pad’s structural morphologies as well as that of the control samples were evaluated via JEOL.JSM- 7600F scanning electron microscope at a magnification of 10000. The test result of the produced samples revealed that the ρ values varied from 1.3123 ± 0.1 – 1.4375 ± 0.2 g/cm3, while φ values varied from 23.40 ± 0.1 – 30.44 ± 0.2%. The values of Ŵ varied from 1.143 ± 0.1– 1.571± 0.5 mg/min. The HB values varied from 76.77 ± 0.1 – 102.28 ± 0.2 BHN, while σ values varied from 26.74 ± 0.1 – 39.64 ± 0.5 N/mm2. The CBP recorded average values of 1.7800 g/cm, 22.23%, 1.127 mg/min, 110 BHN and 43.20 N/mm2 for ρ, φ, Ŵ, HB and σ respectively. Among the prototype brake pad sample produced, sample 5 with composition of 20% sisal, 25% palm slag, 15% epoxy resin, 15% steel dust, 15% silica and 10% graphite powder had values of 1.3329 g/cm3, 23.40%, 1.143mg/min 102.28BHN and 39.64 N/mm2 for ρ, φ, Ŵ, HB and σ respectively, making it the best performed sample, while sample 9 with composition 25% sisal, 20% palm slag, 20% epoxy resin, 15% steel dust, 10% silica and 10% graphite, had average values of 1.3123 g/cm3, 30.43%, 1.572 mg/min, 76.77 BHN and 26.74 N/mm2 for the above parameters respectively was the least performed sample. When compared to the CBP,the best performed sample exhibited a slightly higher φ andŴ of 5% and 1.3% and a lower HB and σ of 7% and 8.2%. The structural morphology of all the samples showed even distribution of grains in the body of the matrix. The study revealed the positive potentials of sisal – palm slag composites as candidate material for asbestos free brake pad.
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    INVESTIGATION OF THE POTENTIALS OF SISAL-PALM SLAG COMPOSITES AS MATERIALS FOR ASBESTOS FREE BRAKE PAD
    (2023-12-15) ANIBABA ADEBOLA DANIEL
    ABSTRACT Asbestos are employed in brake pads on account of their good physico-mechanical properties. However, they are now being avoided because of the health challenges associated with their application. This research investigated the potentials of sisal- palm slag composite material for automobile brake pad production. Ten composite brake pads prototypes were produced in varying proportions of sisal (20-30%), palm slag (20-30%), epoxy resin (15-20%), steel dust (15-20%) and silica (10-15%). The composition was formulated based on the output generated from extreme vertices experimental design. Conventional brake pad (CBP) sample was used as control in the study. Key physical and tribo-mechanical properties such as density (ρ), porosity (φ), wear rate (Ŵ), hardness HB and compressive strength (σ) of the produced brake pad and control were determined following recommended standards and procedures. The produced brake pad’s structural morphologies as well as that of the control samples were evaluated via JEOL.JSM- 7600F scanning electron microscope at a magnification of 10000. The test result of the produced samples revealed that the ρ values varied from 1.3123 ± 0.1 – 1.4375 ± 0.2 g/cm3, while φ values varied from 23.40 ± 0.1 – 30.44 ± 0.2%. The values of Ŵ varied from 1.143 ± 0.1– 1.571± 0.5 mg/min. The HB values varied from 76.77 ± 0.1 – 102.28 ± 0.2 BHN, while σ values varied from 26.74 ± 0.1 – 39.64 ± 0.5 N/mm2. The CBP recorded average values of 1.7800 g/cm, 22.23%, 1.127 mg/min, 110 BHN and 43.20 N/mm2 for ρ, φ, Ŵ, HB and σ respectively. Among the prototype brake pad sample produced, sample 5 with composition of 20% sisal, 25% palm slag, 15% epoxy resin, 15% steel dust, 15% silica and 10% graphite powder had values of 1.3329 g/cm3, 23.40%, 1.143mg/min 102.28BHN and 39.64 N/mm2 for ρ, φ, Ŵ, HB and σ respectively, making it the best performed sample, while sample 9 with composition 25% sisal, 20% palm slag, 20% epoxy resin, 15% steel dust, 10% silica and 10% graphite, had average values of 1.3123 g/cm3, 30.43%, 1.572 mg/min, 76.77 BHN and 26.74 N/mm2 for the above parameters respectively was the least performed sample. When compared to the CBP,the best performed sample exhibited a slightly higher φ andŴ of 5% and 1.3% and a lower HB and σ of 7% and 8.2%. The structural morphology of all the samples showed even distribution of grains in the body of the matrix. The study revealed the positive potentials of sisal – palm slag composites as candidate material for asbestos free brake pad.
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    HYDROGEOLOGICAL CHARACTERISTICS AND QUALITY ASSESSMENT OF GROUNDWATER AQUIFERS IN SELECTED LOCATIONS IN ODEDA LOCAL GOVERNMENT, OGUN STATE, NIGERIA
    (2024-06-25) LANIYAN, ABIODUN BUKOLA
    ABSTRACT Groundwater, a crucial and finite natural resource, plays a pivotal role in providing a reliable and economical water supply globally. This study characterized the water-bearing units within the basement complex environment of Odeda Local Government, Ogun State, Southwestern Nigeria for the assessment of hydrogeological characteristics and water quality for effective planning and development of groundwater resources. Vertical Electrical Sounding (VES) investigations were conducted across fifty-six data points using the Schlumberger array with a maximum half-current electrode separation of 132 m. The lithological and hydrogeological characteristics of the study area were derived from these VES investigations. The vulnerability index was calculated based on key aquifer parameters such as longitudinal conductance, overburden thickness, coefficient of anisotropy, and hydraulic conductivity. The potential groundwater spatial map was generated using basement resistivity, coefficient of reflection, transverse unit resistance, and transmissivity at each sounding point across the study area. Hydrochemical investigations covered Opeji, Itesi, Ilugun, Osiele, Obantoko, Olodo, Obete, Odeda, Alabata, and Isolu towns within Odeda Local Government, involving the collection and analysis of ninety groundwater samples from boreholes and hand-dug well and tested for physical, chemical, and heavy metal contents. The data were further analyzed using descriptive statistics, correlation analysis (CA), and hydrochemical characterization. The results showed diverse geophysical curve types such as H, KH, AH, AA, and A, with predominantly H types indicating the presence of a shallow crystalline basement rock. The inferred lithologies showed between three to five geoelectric layers, each characterized by distinct resistivity values and thicknesses. Protective capacity assessments at VES points indicated a varied vulnerability landscape, with approximately 48% exhibiting poor protection, 39% displaying a moderate level, and 13% showing robust defense against contamination. The potential groundwater spatial map showcased variations, with the Obantoko axis exhibiting mainly low and medium water yield, the FUNAAB axis demonstrating high groundwater potential, and the Odeda axis displaying a varied distribution of high, medium, and low potential zones. Hydrochemical analysis revealed slightly acidic groundwater across the ten locations, with other parameters generally conforming to recommended limits, except for elevated levels of calcium, lead, manganese, and copper. Piper plots illustrated a predominant CaCl2 water type, and Schoeller diagrams highlighted major ion abundance sequences, indicating the dominance of inorganic salts. While most physico-chemical parameters met permissible limits set by the World Health Organisation (WHO) and Nigeria Standard for Drinking Water Quality (NSDQW), elevated concentrations of calcium, lead, copper, and magnesium ions suggested potential signs of impairment. The findings identified optimal sites for proposed borehole installations based on evaluations of aquifer protective capacity, vulnerability and groundwater yield potential characteristics. Hydrochemical analysis showed generally compliant water quality, though some areas had elevated ion levels, requiring remediation to ensure safe drinking water standards. The study characterized the groundwater resources in the area, revealing a diverse hydrogeological landscape with varying vulnerability and groundwater potential essential for future borehole installations.
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    EVALUATION OF CRUMB-RUBBER IN THE STABILISATION OF SOFT SOIL
    (2024-06-25) ADEKANMBI ADEWALE YUSUF
    ABSTRACT The presence of soft soil poses challenges to foundation, thus necessitating the need for ground improvement techniques like weak soil replacement, compaction, and soil stabilization. This study evaluated the effect of crumb-rubber (CR) on selected soft soil. The CR specimen was prepared into sizes of 0.6 mm (CR1), 1.18 mm (CR2), 2.36 mm (CR3) and 4.75 mm (CR4). The soil sample was treated with each of the sizes of CR specimen at percentage replacement of 2.5, 5, 7.5 and 10 %. Each of the Soil-CR mixture was identified as SCRM1, SCRM2, SCRM3, and SCRM4 based on the aforementioned CR sizes respectively, and has four sample mixtures based on aforementioned percentage replacements, with a total number of sixteen samples in all. The geotechnical and chemical properties of the soil, CR, and SCRMs were examined by performing tests such as Natural Moisture Content (NMC), Specific Gravity (Gs), Plasticity Index (PI), Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), X-ray Fluorescence (XRF), Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD) and Scan Electron Microscopy (SEM). The results showed that the soil has high water holding capacity of 23.5 %, light weighted (Gs = 1.62), and has low plasticity (PI = 2.72) and thus classified as Low Plastic Organic Silty Soil (OL). It has a UCS value of 50 kN/m2 and CBR value of 10 %. The major oxides, functional groups, and crystal compounds presents in the soil were Ferric oxides (Fe2O3), hydroxyl (O-H) group, and quartz (SiO2), respectively with a spongy surface. The CR was found to be light weighted Gs (between 1.01 and 1.06), and the major oxides, functional group, and amorphous compounds present were Zinc Oxides (ZnO), Aromatic (C-H), and Polystyrene, respectively. Similarly, the SCRMs showed increase in Gs (which ranges from 1.99 to 2.30), the highest value of PI, UCS and CBR were obtained at 5% optimum CR replacement as 15.58% for SCRM4 (4.75 mm), 393.36 kN/m2 for SCRM2(1.18 mm) and 16.61% for SCRM4 (4.75 mm) respectively. The XRF result on optimized samples (SCRM2 and SCRM4 at 5%) indicated the presence of SO3, decrease in Fe2O3, ZrO2, TiO2 while there is increase in ZnO, SiO2, CaO, and Al2O3 in the samples. The FT-IR result showed that hydroxyl (O-H) group was maintained for both samples, while XRD result showed the presence of polypropylene in SCRM2 and methyl-styrene in SCRM4. The SEM images showed that the SCRM4 appeared more smooth and cohesively bonded while SCRM2 appeared intermediate compared to the virgin soil. This study revealed that there are improvements in the Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) of the selected soft soil with crumb-rubber as stabilizer at 5% optimal percentage for SCRM2 and SCRM4 for respectively.
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    INVESTIGATING CONDUCTIVE FIBER AND INDUCTION HEAT ENERGY EFFECTS ON FATIGUE RESISTANCE AND RESILIENT MODULUS OF HOT MIX ASPHALT
    (2024-07-20) ODELADE, HASSAN OPEYEMI
    ABSTRACT Cracks in flexible pavement are inevitable due to traffic loading, fatigue, construction deficiencies and environmental factors. It causes water ingress which ultimately leads to the failure of the pavement structure. This study investigated conductive fiber and induction heat energy effects on fatigue resistance and resilient modulus of hot mix asphalt. The materials used include, coarse and two variants of fine aggregates, bitumen, and kitchen steel wool as the conductive fibre. Preliminary tests such as particle size analysis, specific gravity, flash and fire point determinants were carried out to evaluate the properties of the materials. Marshall test was used to determine the optimum bitumen content (OBC) and optimum steel wool content (OSWC) of the asphalt matrix samples. Steel wool content (SWC) in the asphalt samples was varied from 0 to 6% at 2% interval. Scanning electron microscopy (SEM) and X-ray fluorescence (XRF) test were used to evaluate the microstructure of the asphalt samples. Self-healing properties of these samples under microwave induction heating at 110 ⁰C were examined by evaluating their electrical conductivity, heat transmission rate (HTR) and extent of closure of induced cracks. The indirect tensile fatigue test (ITFT) was carried out to determine the fatigue resistance and resilient modulus performance of the samples under three different tensile loading stresses of 250, 400 and 550 kPa. The preliminary tests of the aggregates revealed that coarse aggregate had a specific gravity of 2.68 and was classified as uniformly graded. The two variants of fine aggregates, sharp sand and stone dust, were well graded soil and had specific gravities of 2.64 and 2.57 respectively. The kitchen steel wool had a specific gravity of 6.61. The bitumen material had a specific gravity of 1.01 with flash and fire points of 256.7 and 325 ⁰C, respectively. The OBC of the sample was 5.94% while OSWC by weight of OBC was 2.83%. In comparison with the control mix, the stability of the modified asphalt mix with the OSWC decreased by 15.36% from 9.24 to 8.01 KN while that of flow of the mix decreased by 2.37% from 3.88 to 3.79 mm. The SEM and XRF analysis results revealed variations in the quantities of the elemental constituents of the modified mix, as the SWC increases. The electrical conductivity increased from0.1x10-7 to 0.1x10-1 μS/cm with increase in SWC from 0 to 2% and remained constant with further increase to 4%. The HTR of 0.10, 0.14 and 0.18 ⁰C/min were respectively obtained for 0, 2 and 4%. The average resilient modulus of the asphalt mixes obtained from the ITFT increased from 4084.06 to 5578.76 MPa as SWC increased from 0 to 2% and remained relatively constant with further increase to 4%. Also, the asphalt mix with 2% SWC performed optimally in fatigue resistance and resilient modulus. The study concluded that the fiber enhanced the self-healing properties of the asphalt.
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    DEVELOPMENT OF A MICROBIAL FUEL CELL FOR WASTEWATER TREATMENT AND RENEWABLE ENERGY GENERATION USING LOCALLY PRODUCED ELECTRODES
    (2024-07-20) NKESHITA, FIDELIS CHUKWUMAH
    ABSTRACT The need for clean and sustainable energy, coupled with indiscriminate disposal of wastewater and recycling of waste materials necessitated the need to develop low-cost innovative bioelectrochemical systems. This study developed laboratory-scale microbial fuel cells (MFCs) to treat locust bean wastewater (LBWW) and generate renewable energy using locally produced electrodes sourced from palm kernel shell activated carbon (PKSAC) and used battery graphite. Preliminary physico-chemical, proximate, microbial (isolation, characterization, biochemical test), and molecular parameters were determined. Two electrode types were fabricated: EA (PKSAC)/Graphite/styrene binder) and EB (PKSAC)/Graphite/Paraffin wax binder), in which the PKSAC were partially replaced with 0, 25, 50, and 75 % of graphite and categorized as EA1, EA2, EA3, EA4 and EB1, EB2, EB3, EB4, respectively. Double-chambered 1 L MFCs were constructed using transparent plastic containers, with electrodes connected by copper wires and a horse-shaped salt bridge for proton transfer. Physico-chemical (electrical conductivity (EC), total dissolved solids (TDS), chemical oxygen demand (COD), total organic carbon (TOC), Nitrate, Sodium, and Potassium), microbial, and microstructural analyses were conducted before and after the experiments, with measured daily readings for voltage and current values. Experiments were conducted under pH 3.7 and neutral pH conditions by dosing the anolyte with 0.1 M NaOH. All MFC reactors operated under room atmospheric conditions. Statistical analyses were implemented using MS Excel and Python programming. The results showed that the isolated microbial strains (Priestia aryabhattai) were in LBWW. The MFC operations detected the formation of biofilms on the anode surfaces indicating the presence of electrogenic bacteria. In MFCs using EA electrodes, LBWW at a pH of 3.7 generated 515 mV (p < 0.05) and 27 mA (p < 0.05) while LBWW using EB electrodes at a pH of 3.7 generated 451 mV (p < 0.05) and 15 mA (p > 0.05). At adjusted pH of 7.0, MFC with EA electrodes improved the outputs to 1040 mV (p < 0.05) and 213 mA (p > 0.05) while MFC with EB electrodes improved to 1078 mV (p < 0.05) and 213 mA (p < 0.05). The LBWW treatment with EA electrodes at a pH of 3.7 showed lower treatment efficiencies: EC 6.08%, TDS 3.00%, COD 9.76%, TOC 9.23%, nitrate 19.23%, sodium 7.89%, and potassium 11.48%. The treatment efficiencies improved when the pH was adjusted to 7.0 using 0.1M NaOH: EC 26.31%, TDS 25.51%, COD 22.79%, TOC 36.92%, nitrate 38.46%, sodium 31.58%, and potassium 31.14%. Statistical analyses revealed LBWW with EA electrodes at pH 3.7 exhibited statistically significant outputs (p < 0.05) for both voltage and current readings. It was observed to be statistically significant for voltage readings but insignificant for current readings when the pH was adjusted to 7.0. LBWW with EB electrodes at pH 3.7 and pH 7.0 showed similar trends of statistical significance (p < 0.05). The study demonstrated that wastewater treatment and bioelectricity generation could be achieved using locally produced electrodes in microbial fuel cells.
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    ANALYSIS OF TECHNICAL AND NON-TECHNICAL LOSSES IN AN ELECTRICITY DISTRIBUTION SYSTEM
    (2024-09-04) ERINOSHO, JEREMIAH OLUWAMAYOWA
    ABSTRACT The quality of service delivery from electricity distribution networks (EDNs) despite the huge post-privatization intervention fund provided by the Federal Government of Nigeria is still far from being satisfactory due to aggregate technical, commercial and collection (ATC&C) losses. This study evaluated ATC&C losses in an EDN using FUNAAB 33kV and Obantoko 11kV distribution network feeders as case studies. The weekly data of injected power, energy consumed and energy billed on both feeders were collected from Ibadan Electricity Distribution Company (IBEDC) for a period of six years (2018-2023). The power losses and voltage drops on the feeders were calculated using the formulated power equations comprising the parameters load factor, conductor length, conductor cross-sectional area, conductor resistivity,maximum feeder loading, line voltage and power factor. The billing data were analysed to determine the commercial and collection losses. Physical assessment of the feeders as built was also carried out. The obtained results revealed that the highest power losses of 11.74 and 6.682 MW, respectively, were observed on FUNAAB 33 kV and Obantoko 11 kV feeders. These losses which occurred in the year 2022 corresponded to 5.86 and 10.85% losses in power, of 200.4 and 61.56 MW, respectively, injected into both feeders. The voltage drop on FUNAAB 33 kV feeder over the study period ranged between 11.21 to 12.14% while it ranged between 17.96 to 18.45% on Obantoko 11 kV feeder. These values were found to exceed the permissible 10% limit of the operating voltage. The highest voltage drop of 12.14 and 18.45%, respectively observed on FUNAAB 33 kV and Obantoko 11 kV feeders occurred in the year 2022. Further observations revealed that 68% of the 20.26 km length of Obantoko 11 kV feeder involved the use of under-rated 70 mm2aluminium conductor (AlC), leading to high power loss and voltage drop unlike FUNAAB 33 kV feeder where 63% of the 57.4 km length of the line was constructed with the standard 150 mm2AlC. Analysis of commercial and collection losses on both feeders revealed a remarkable energy accountability challenges throughout the study period, a continual gap in energy received and billed was evident.The highest commercial loss of ₦3,683,071 on FUNAAB 33 kV feeder occurred in the year 2022 while the collection loss was highest in the year 2020 at a worth of ₦328,752,293. Similarly, the highest commercial loss of ₦4,202,467experienced on Obantoko 11 kV feeder occurred in the year 2023 while the highest collection loss of ₦149,056,487 was experienced in the year 2021.These results were indication that feeder characteristics, billing and consumer enumeration systems were key factors that appreciably influenced ATC&C losseson the case feeders. The aggregate technical, commercial and collection losses analysed in the study revealed the operational inefficiencies of the considered electricity distribution network feeders.