College of Engineering

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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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
POWER LOSS MINIMIZATION AND VOLTAGE PROFILE IMPROVEMENT ON AN ELECTRICAL POWER DISTRIBUTION NETWORK USING OPTIMALLY PLACED PHOTOVOLTAIC ENERGY SOURCE
(2024-09-20) FOLARANMI, KAZEEM SAULA
ABSTRACT In recent times the adoption of distribution generation in power system has been on the increase due to the progress recorded in exploiting renewable energy resources for electrical power generation at distribution level and the necessity for enhanced power quality. However, inappropriate placement of these resources could result in increased power loss and poor voltage profile. Therefore, this study assessed the effect of optimally placed photovoltaic energy source (PVES) on power loss and voltage profile of an electrical power distribution network (DN). Power flow analysis was performed on standard IEEE 33-bus and Ilesa 33-bus DNs without and with inclusion of PVES using forward and backward sweep method. The optimum location and the corresponding PVES size were determined using both sensitivity analysis (SA) and whale optimisation algorithm (WOA). The simulations were carried out in MATLAB R2023a software environment. The performance of WOA on standard IEEE 33-bus DN was validated in comparison with the results obtained using grey wolf optimization (GWO), adaptive shuffle frogs leaping algorithm (ASFLA) and one rank cuckoo search algorithm (ORCSA). The power flow results of IEEE 33-bus DN without PVES showed that buses 5, 11 and 23 with voltage magnitudes of 0.9303, 1.0558 and 1.0571 p.u., respectively violated the statutory voltage limit of 0.95 to 1.05 p.u. Buses 5, 14, 19 and 31 of Ilesa 33-bus DN with voltage magnitudes of 1.0558, 0.9237, 0.9312 and 1.0542 p.u., respectively also violated the statutory limit. The total active power loss (TAPL) for IEEE 33-bus and Ilesa 33-bus DNs without PVES were 195.51 MW and 247.29 kW, respectively. The optimal locations of PVES unit for the IEEE 33-bus DN with SA were buses 10, 27, 28 and 29 with sizes 6.55, 10.00, 8.55 and 5.25 MW, respectively while with WOA were buses 4, 5 and 27 with sizes 8.5, 5.5 and 5.25 MW, respectively. Similarly, the optimal locations of PVES for Ilesa 33-bus DN with SA were buses 5, 14, 20, 27 with sizes 10.0, 12.5, 10.5, 15.0 and 10.0 kW, respectively whereas with WOA were buses 4, 8 and 17 with sizes of 12.50, 10.50 and 10.00 kW, respectively. The voltage profiles of both networks considered appreciably improved and fell within the statutory limit with both unoptimised PVES and optimised PVES installed. The TAPL of the IEEE 33-bus DN with unoptimised PVES, PVES optimised with SA and PVES optimised with WOA were 164.71, 163.30 and 153.30 MW, respectively while the value for the Ilesa 33-bus DN were 235.61, 243.51 and 201.97 kW, respectively. The percentage of TAPL on the IEEE 33-bus system with WOA, GWO, ASFLA and ORCSA were 21.6, 10.7, 20.2 and 21.2%, respectively; indicating WOA outperformed the other optimisation approaches for the placement of PVES unit. This study achieved a minimised total active power loss and an enhanced voltage profile on IEEE 33-bus and Ilesa 33-bus distribution networks with the application of appropriate optimisation technique for the photovoltaic energy source placement.
THE EFFECT OF TRAFFIC SHAPING AND DYNAMIC BANDWIDTH ALLOCATION AS CONGESTION CONTROL MEASURES IN INTERNET PROTOCOL NETWORKS
(2024-09-20) JACKREECE, BEKE ABEL
ABSTRACT Internet protocol networks are experiencing increased traffic load, resulting in congestion. This congestion can have detrimental effects on the network performance and hence the need for congestion control. This research assessed the effectiveness of traffic shaping and dynamic bandwidth allocation as congestion control measures in Internet Protocol (IP)networks. A typical IP network topology was designed with end devices configured. End devices used were five routers, three switches, Hyper-Text Transfer Protocol (HTTP) server, Domain Name Server (DNS), File Transfer Protocol (FTP) server, email server, a network controller, twenty-four personal computers (PCs), six IP phones and two printers. A hybrid of ring-star topology was used for the designed network and it was done in the Cisco packet tracer virtual laboratory. Devices’ IP addresses and routing protocols were configured and verified using appropriate commands. Four classes of traffics, HTTP, FTP, email and Internet Control Message Protocol (ICMP), were generated and simulated to assess the performance of the designed network. The Quality of Service (QoS) policy was implemented on the designed network through class-map, policy-map and service-policy. The QoS policy was imposed on routers 2, 4 and 5 while routers 1 and 3 were left because the two routers served as dynamic host configuration protocol servers for IP phones. The results showed that on router 2, the HTTP traffic experienced packets delay of about 33% while 1018 out of 1917 matched packets were successfully transmitted in FTP but with 3972 delayed packets. The ICMP traffic had all 1807 matched packets successfully sent without any drop. The email traffic experienced highest congestion as only 470 out of 2118 packets were successfully sent. Traffic analysis on router 4 revealed that HTTP traffic at 5 minutes offered rate of 1.854 kbps was associated with 1739 delayed packets while 815 packets were transmitted. The FTP traffic had 759 packets transmitted out of 759 matched while the ICMP traffic had 780 and 781 matched and transmitted packets, respectively. The email traffic was the worst hit by the imposed QoS on router 4 as out of 2095 matched packets, a paltry 81 were successfully transmitted. The relative values of matched to transmitted packets showed that all class of traffics fared better on router 5. The drop rates for HTTP, FTP, ICMP and email traffics were 0.418, 0.424, 11.6244 and 0.100 kbps, respectively, on router 5. These results suggested that the QoS favoured ICMP traffic followed by FTP traffic on router 2 while on router 4, the QoS supported HTTP, FTP and ICMP traffics than the email traffic. Observations on router 5 might be due to assigned bandwidths to each class of traffics considered. The results showed that, with imposed QoS, each of the HTTP, FTP, ICMP and email traffics experienced varying degrees of congestion at different routers while traversing the IP network. It can be concluded that the traffic congestion in Internet protocol networks could be mitigated via appropriate traffic shaping and dynamic bandwidth allocation.
APPLICATION OF THYRISTOR CONTROLLED SERIES CAPACITOR FOR PERFORMANCE IMPROVEMENT OF NIGERIA POWER TRANSMISSION NETWORK
(2024-09-20) BASIRU WASIU OLALEKAN
ABSTRACT The population and industrial growths coupled with the limited capacity of the power transmission grid in Nigeria has created a wide margin between electricity supply and demand, with attendant high power loss and voltage instability. The desire for efficient power quality delivery to electricity customers has led to emergence of flexible alternating current transmission systems (FACTS). This study examined the effect of thyristor-controlled series capacitor (TCSC), a series FACTS compensator, on the performance of the Nigerian 330 kV, 30-bus electric power transmission grid. The static response of power system without and with TCSC compensation was modelled using Newton-Raphson based load flow equations. The NEPLAN software was employed for the simulation of the system response without and with compensation. The voltage magnitudes and line loadings of the system were determined and compared with appropriate operating limits to identify possible violations. The system active power loss was also evaluated. The obtained resultsrevealedthatbefore the compensation, six buses which are Gombe,Kano, Jos,NewHaven,CalabarandOnitsha withvoltagemagnitudesof0.6608,0.8138,0.8141,0.9002, 0.9319 and 0.9466 p.u., respectively, violated statutory voltage limit of 0.95 to 1.05 p.u. The system overallactive power loss was219.08MW. TwobranchesOkapi-CalabarandAlaoji-Calabar also exceededthe recommended voltage-ampere limit of 80% with 101.69and 84.19 % loadings, respectively. The installation of TCSC in the system mitigated all thevoltagemagnitudeviolations with constrained bus voltages improved to 0.9715,0.9777, 1.0022, 1.0247, 1.0043 and 1.0312 p.u., respectively; the values which are now within the statutory limit. The overall active power loss of the system decreased to 174.06 MW, giving an improvement of 20.55% in the active line flow. However, Alaoji-Calabar branch with a loading of 80.61% was still overloaded. The installation of TCSC and an additional line across the branch further improved the overall voltage profile of the system and eliminated the line loading violations. The overall active power loss further reduced to 161.54 MW, leading to an improvement in the active line flow by 26.26%. The results showed that the combined use of TCSC and line expansion produced a better impact on the system bus voltage and power profiles along the transmission network. The compensation provided by the thyristor controlled series capacitor together with the line expansion improved the performance of the Nigerian electric power grid and system bus voltages.
ASSESSMENT OF THE EFFECT OF SOME FACTORS AFFECTING SOIL RESISTIVITY FOR OPTIMAL PERFORMANCE OF A GROUNDING SYSTEM.
(2024-09-25) AKINYEMI, MOFOLORUNSHO
ABSTRACT The impedance of the discharge path of a fault current defines the quality of a grounding system. Thisstudy assessed the effect of depth (D), temperature (T), moisture content (MC) and soil texture (ST) onsoil resistivity () for optimal performance of a grounding system. The measurements for two differentseasons which are rainy season (July 2023) and dry season (January 2024) were carried out at 10locations in Federal University of Agriculture, Abeokuta as a case study. These locations wereCOLENG, Postgraduate (PG) School, COLPHYS, Health Centre (HC), Works and Services Unit(WSU), COLANIM, COLVET, COLPLANT, Student Union Building (SUB) and COLBIOS. The wasmeasured via Wenner method at D of 0.150, 0.450, 0.756, 1.110 and 1.490 m automatically selected bythe Herojat Rhomega-Smart Resistivity Meter deployed. The MC and ST were determined for the sameD values by laboratory analysis of five samples of 5 kg soil from each location. The ST class wasidentified using IEEE Standard 81-2012 and the soil T at different D values was measured using athermometer. The relationship between the dependent variable () and the independent variables (MC, Tand D) was modelled via the use of multiple linear regression (MLR) for each location for both seasons. The level of contribution of D, T and MC to was determined by the coefficient ofdetermination (R 2). The rainy season measured at COLENG, PG School, COLPHYS, HC, WSU,COLANIM, COLVET, COLPLANT, SUB and COLBIOS ranged between 31.6-262.0, 78.5-222.5,113.7-222.5, 48.4-167, 91.0-184.0, 61.6-124.7, 122.0-177.5, 190.0-341.5, 100.3-203.0 and 84.7-116.0Ωm, respectively while the dry season values ranged between 123.7-462.5, 106.5-448.5, 178.5-1128.5,271.1-493.0, 111.0-306.0, 70.1-257.5, 140.0-656.5, 320.5-853.0, 188.0-382.5 and 92.2-365.5 Ωm,respectively. These values were typical of three ST classes which included sandy loamy, sandy clayloam and loamy sand. The MC measured for both seasons at the locations ranged between 9.60-20.30,2.06-16.4, 2.39-12.40, 3.40-8.30, 3.80-23.90, 9.40-16.90, 12.20-17.60, 10.10-12.00, 8.40-18.10 and13.20-15.10 %, respectively. Similarly, the soil T measured during rainy season ranged between 28-31,27-30, 30-31, 30-31, 29-30, 29-30, 28-29, 29-30, 29-30 and 29-30oc , respectively whereas the valuesranged between 39-40, 35-36, 37-38, 37-38, 38-39, 37-38, 37-38, 38-39, 37-39 and 35-36oc ,respectively, for dry season. The lowest was measured at nearly all the locations for both seasons at D of 1.490 m where MC was highest and T was lowest. The only exception to this trend occurred at SUBand COLPLANT where was lowest at 0.150 m and HC where the value was least at 0.150 m and 0.450m, respectively, during rainy season. The 20 MLR models developed for the 10 locations for both rainyand dry seasons revealed that MC, T and D collectively contributed better to than the individual variables due to higher value of multiple R 2 recorded. This study showed that the soil resistivity of thetest locations was influenced by soil texture, moisture content, temperature and depth.
ASSESSMENT OF THE STRENGTH AND DURABILITY OF GEO-POLYMER CONCRETE CURED IN LAGOON WATER
(2025-01-20) EWETADE Abayomi Olukayode
ABSTRACT Geopolymer Concrete (GPC) presents a suitable alternative to Portland Cement Concrete (PCC) in infrastructure projects due to its friendly production effect to the environmental. The production of Portland Cement (PC) contributes significantly to greenhouse gas emissions, and its poor performance in aggressive environment. This study investigated the strength and durability of GPC in Lagoon water. With the target strength of 50 Mpa.The GPC comprises of fine and coarse aggregates, metakaolin (MK) with ground granulated blast furnace slag acting x as the binders, sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) which provided the alkaline medium. Reinforced GPC 100 × 100 × 600 mm beams, 100 × 100 x 100 mm cubes and 100 × 200 mm cylinders were prepared for flexural, compressive and split tensile testrespectively. Two specimens were prepared; the main specimen was cured in lagoon water (GPCW), while the control specimen was cured at ambient temperature (GPCD), for 28, 90, 180, 270 and 365 days. A finite Element program ANSYS was used to simulate the mechanical properties of both specimen. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy were used to determine the microstructural and elemental composition of the specimens, respectively.Results showed an increase (111.31 to 146.22 Mpa)in compressive, flexural and splitting tensile on an average of 38.8% from 28 to 180 days, with a decrease of (146.22 to 205.25 Mpa) 23.6% by the 365th day for the GPCD samples. The GPCW showed a reduced strength of (45.02 to 40.01 Mpa) 43% when compared with GPCD, and it experienced reduction in strength at an average of 11% from 28 to 365 days. Deflection of the reinforced beams indicated a steady increase from 28 to 365 days, mirroring the general deflection behaviour of conventional concrete's linear elasticity. SEM revealed differences in GPCD and GPCW with the latter displaying less dense structures with larger voids, consistent with the reduction in compressive strength over time. Conversely, GPCD samples had a denser microstructure, resulting in higher strength. Unreacted MK particles were visible in SEM images, indicating incomplete geopolymerisation in certain areas of the GPCW.XRD analysis highlighted a stable calcium-to-silicon (Ca:Si) ratio in GPCW, with variations in the silicon-to-aluminum (Si:Al) ratios between GPCW and GPCD specimens. Efflorescence substance was observed in the GPCD samples after 180 days. The analysis of the substance revealed a high level of calcium oxide (CaO) and iron oxide (Fe2O3). These oxides led to the reduction in strength after 180 days. The simulation of both GPC samples revealed the elastic strain, normal stress and the deformation generated within the concrete samples during the experiment. Statistical analysis showed the difference between the experimental and simulation strength results to have P ≤ 0.05 confidence interval. This confirmed that the stress-strain obtained in the ANSYS simulation is a true reflection of what happened in the experiment. The study found that Geo-polymer Concrete had weak durability and mechanical properties in an aggressive environment, but strong mechanical strengths in non-aggressive environment making it a promising alternative to PortlandCement.
DETECTION AND REMEDIATION OF CRITICAL NODES AND BRANCHES IN AN INTERCONNECTED POWER SYSTEM NETWORK
(2025-06-06) OLAJIDE, SAMUEL ADEYEMI
ABSTRACT Voltage instability has been a major concern to power supply utilities and its effect has resulted into system voltage collapse and high power losses. This study employed the fast voltage stability index technique (FVSI) to detect critical nodes and branches in an interconnected power system network, considering the IEEE 57-node and Nigeria 34-node electricity grids as case studies.The detected critical branches were corrected using static var compensator (SVC). Load flow modelling and simulation were carried out to determine the node voltage, phase angle and active power loss along the network lines. Simulations were done for the base case and the contingency-variation of the reactive loads in the network until the FVSI value approaches one (1) to determine the maximum permissible load of each load nodes. The ranking in the system was done by sorting the maximum permissible load, of the load nodes in ascending order. The smallest maximum permissible load was ranked highest implying that the node is the weakest in the system. Thereafter, the node voltage magnitudes and branch active power losses were computed and compared for the two case networks. The results revealed that, for IEEE 57-node power system, 43 node voltages out of 57 node voltages were outside the statutory limit of ± 5%. The total active power loss was 65.303 MW. The inclusion of SVC in the system corrected the voltage limit violations on the critical nodes while the total active power loss was reduced by 43.29% amount to 37.039 MW. In the case of Nigeria’s 34-node power network, voltage limit violations occurred at two nodes which were node 2 (BirninKebbi) and node 13 (Kano T.S). The voltages at the two buses were outside the acceptable limit of ± 5%. The total active power loss was 134.920 MW. The SVC introduction into the system normalized the voltages on the critical nodes with the total active power loss reduced by 52.95% amount iv to 63.481 MW. These results were indications that FVSI when appropriately applied can aid the detection of critical nodes and branches in power system network while the SVC installation can minimize the power loss and improve the voltage magnitude of the system. This study established the suitability of fast voltage stability index technique for the weak nodes and branches detection in a power system and static var compensator (SVC) for possible remedial action.
DEVELOPMENT OF AN EXTRUDING MACHINE TO PRODUCE INTERLOCK BRICKS FROM SAND AND PLASTIC WASTE
(2025-06-25) ADESINA, ISRAEL KOLAWOLE
ABSTRACT Plastic production comes from fossil fuels and they are non-biodegradable, thus resulting into wastes that cause nuisance in the environment. Therefore, an alternative plastic waste management solution is crucial. The need to find alternative construction materials that are readily available and cheaper. This research work aimed at developing an extruding machine to produce melted plastic material that will serve as a binding agent in the production of interlock bricks. The extruder was designed and fabricated following standard design specifications and parameters. The machine was equipped with a temperature controller, a thermocouple, a band heater, a contactor, a switch, an electric motor and a voltage regulator. Five experimental stages were considered, each stage having a study samples and a control sample. Stage 1,stage 2, stage 3, stage 4 and stage 5 had a percentage mix ratios of 70:30, 60:40, 50:50, 40:60 and 30:70 respectively, of which the control samples were made using Portland cement as the binder and the study samples were made with melted waste plastic as binder. The samples were subjected to compressive strength, percentage of water absorption and absorption resistance tests for the samples and controls. The compressive strengths obtained for the study samples were: 10.29, 14.22, 20.25, 20.94 and 17.37 N/mm2, while the values for the control samples were: 16.45, 16.81, 24.58, 30.33 and 32.27 N/mm2 for the above mentioned mix ratios respectively. The results showed that interlock bricks made from Portland cement has better compressive strength in all stages compared to the samples made with waste plastics, the maximum compressive strength obtained from the controls was 32.27 N/mm2 while that waste plastic is 20.94 N/mm2. The maximum percentages of water absorption for the control samples and study samples are 4.0% and.5% respectively. However, the maximum water absorption resistance percentage for control samples and study samples are 0.2% and 7.2% respectively. This implies that the interlock bricks made from melted plastic waste can be used for roads expected to carry lighter traffic such as parking lot, pathways (walkways), it could also be suitable for areas with high water table or a waterlog areas. The result of the research findings, it is recommended that 40: 60 mix ratios of waste plastic to sand be used. However, to produce 2kg weight of an interlock bricks at 7:3 (70% sand and 30% waste plastic); 0.6kg of waste plastic was used (44 pieces of plastic bottle with each an average weight of 13.73g without plastic bottle cap and neck). Therefore, a considerable number of plastic wastes can be managed and reused through this process of production of interlock bricks from waste plastic and river sand (sharp sand).

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