College of Engineering
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Item Utilization of periwinkle and palm kernel shells in load-bearing ecofriendly interlocking concrete paver(Frontier in Built Environment, 2025-01-10) Olofinnade, Olofinnade; Awoyera, Paul; Edemirukewa, Kelvin; Ogundipe, KunleIn recent times, increasing demand for raw aggregate has emphasized the need for construction industry to adopt sustainable practices by exploring alternative materials, such as agro-waste, to address resource depletion and reduce environmental pollution., This current study investigated the suitability of combining discarded periwinkle shell (PWKS) and palm kernel shell (PMKS) at low-replacement volumes to partially substitute granite in ecofriendly loadbearing cement-based interlocking paver units for use on medium-duty traffic roads. 108 paver samples were produced, targeting a 28-day strength of 30 MPa, using a mix proportion of 1:1:2 (cement: sand: granite) and water-cement ratio of 0.50. Physical and chemical compositions of materials are examined, while the produced paver samples were tested for their water absorption, compressive and split-tensile strengths properties. The influence of curing (immersion and open air) on the strength development was evaluated. Findings showed that the shells recorded low physical properties but increased water intake tendency. A gradual decrease in the strength performances of the pavers was observed as the amount of PWKS and PMKS increases in the mixes. The water absorption tendency increases with increasing PMKS and PWKS levels. Pavers cured by complete immersion in water recorded good strength and achieved the 30 MPa compared to open air cured pavers. This study recommends load-bearing pavers of up to 30 MPa can be made by combining PMKS and PWKS at a lowreplacement level of 5% deployed for medium-traffic roads, but with adequate curing technique. Outcomes showed the viability of incorporating periwinkle and palm kernel shells as aggregate in making standard paver units of adequate strength and resistance to water to promote sustainable construction practices.Item DEVELOPMENT OF AN ADAPTIVE VIRTUAL SYNCHRONOUS GENERATOR-BASED FREQUENCY CONTROL STRATEGY FOR HYBRID AC/DC MICROGRIDS(Covenant University, Ota, 2026-08) BELLO, Abiodun Yusuff; Covenant University, DissertationThe rapid transition to sustainable energy sources has led to the large-scale integration of renewable energy technologies such as solar and wind power into today's power grids. These renewable resources do not generate mechanical inertia like conventional synchronous generators; the grids increasingly risk becoming more unstable when frequencies drop. This is particularly challenging in hybrid AC/DC microgrids, where both AC frequency and DC-link voltage must be controlled simultaneously, and Virtual Synchronous Generator (VSG) control is an efficient solution. A control algorithm is implemented to make inverters behave like the inertial and damping characteristics of a synchronous machine. However, most current VSGbased schemes use fixed values for virtual inertia and damping, which fail under varying disturbance magnitudes. Deviating from a fixed inertia value, this research designed and tested an adaptive VSG-based frequency control method for an isolated hybrid AC/DC Microgrid in MATLAB/Simulink R2024b. Real-time frequency deviation and rate of change of frequency (RoCoF) parameters are used to adapt the VSG frequency control. The interlinking converter was tested under two different load disturbances of opposite nature of 2s, i.e., load decrease and load increase, and compared with the conventional fixed-inertia controller (H = 0.5 kg·m²). In both scenarios, the inverter was found to be electrically stable, and the adaptive inertia was found to be sensitive to each disturbance, showing that it changes its operating condition from 0.5 kg·m² to approximately 0.6 kg·m² instead of remaining fixed; importantly, in each load change scenario, it was observed that the adaptive VSG performed a reduced transient frequency deviation than the conventional controller.Item GEOGRAPHIC INFORMATION SYSTEM-BASED OPTIMIZATION OF MUNICIPAL SOLID WASTE COLLECTION AND TRANSFER ROUTE FOR OTA, OGUN STATE, NIGERIA(Covenant University, Ota, 2026-09) ACADEME, Sunday Oyaogbode; Covenant UniversityRapid urbanization and industrial expansion in Ogun State, Nigeria, particularly in Ota, have exacerbated the challenge of Municipal Solid Waste (MSW) management. Inefficient waste collection and travel distance associated with vehicles route have led to prolonged driving times, high fuel consumption, and escalating operational costs, resulting in delayed waste collection and increasing public health and environmental concerns. In response to these challenges, this study is focused on examining the identified inefficiencies in existing MSW collection routes in Ota and to evaluate the use of Geographic Information System (GIS) based optimization to enhance operational efficiency and sustainability. This research employed a combination of primary and secondary data sources. A total of 500 household questionnaires were successfully retrieved across seven locations in the study area, focusing on demographic characteristics, waste disposal practices, perception and awareness of waste management. Primary data collection included key informant interviews, household observations, and field inspections. These were analyzed statistically using SPSS to establish patterns in waste generation and public participation in disposal systems. Secondary datasets were obtained from records of the Ogun State Waste Management Authority (OGWAMA), including vehicle lists, fuel expenditures, and disposal points. To complement this, a field survey was conducted using Global Positioning System (GPS) devices installed on collection vehicles to monitor movement across seven study locations, comprising five residential and two highway routes. In total, 18 monitored trips were recorded over four months. The ArcGIS Pro Network Analyst extension, applying Dijkstra’s shortest path algorithm, was used to generate optimized routes. The analysis revealed that highway routes were generally better managed and more efficient than residential routes, which were often constrained by congestion, narrow road access, and irregular service. Overall, existing travel routes covered 532.74 km daily with a driving time of 1,742.39 minutes. Optimized routes reduced this to 431.28 km and 1,403.12 minutes, representing reductions of 19.0% in distance and 19.5% in time. Fuel consumption under existing operations averaged 163.82 litres daily, whereas optimized routes required 132.25 litres, a saving of 31.57 litres/day. This equates to approximately ₦37,878.68 (US$27.06) in daily savings and about ₦2.94 million (US$2,101.95) annually. The drivers’ survey revealed that optimized routes are currently not used due to barriers such as congested market roads, height restrictions, low hanging cables, parked vehicles, and limited awareness. Despite this, 71% of drivers indicated that optimized routes would improve efficiency, though 29% remained uncertain, reflecting infrastructural and operational constraints. The study demonstrates that the application of GIS based optimization can improve waste collection in Ota by reducing costs, increasing efficiency, and lowering environmental impacts. These findings provide a replicable model for other African cities and align with global sustainability goals including SDG 11 and SDG 12.Item DEVELOPMENT OF A HIGH-PERFORMANCE FIBER-REINFORCED MORTAR COMPOSITE AS A SUSTAINABLE BUILDING MATERIAL(Covenant University, Ota, 2026-08) NAKADE, Fun-Akede Afingi; Covenant University, DissertationThe construction sector is responsible for 5-10% of the global CO₂ emissions, most of which come from the production of concrete. The research interest is shifting towards green cementitious and fiber composites as an alternative to traditional materials, as they are lightweight, renewable and efficient. Traditional decorative and insulation panels in tropical countries, like Nigeria, are usually made with harmful chemicals, and coconut coir, an abundant agricultural by-product, is not widely used. This study aims to create a coir–glass fiber reinforced mortar composite to improve the indoor environmental quality and durability of buildings. It also includes supplementary cementitious materials, Palm Kernel Shell Ash (PKSA) and Ground Granulated Blast Slag (GGBS) and looks at gaps in literature regarding fiber lengths <10 mm and mid-range fiber content (0.1–0.6%). The coir fibers are treated with alkali solution for improving performance. The physical and mechanical properties, water absorption, thermal conductivity and the microstructural behavior (SEM-EDX, XRF) of the composite were evaluated. The neural fitting tool provided in MATLAB®2025a was used to model and predict the compressive strength. The results indicated that mercerization process led to decrease in fiber diameters (10-30%) and increased the resistance to chemicals. The results of mechanical analysis showed that low coir content and high glass content (PC+CF0.1+GF0.6) had the highest compressive and flexural strength, whereas high coir content had led to an increase in air voids and decreased matrix compactness. Additionally, the combination of 20% GGBS and PKSA in PC+CF0.2+GF0.5 sample has the best performance in both mortar and concrete. Also, samples containing PKSA exhibited the lowest thermal conductivity (K ≈ 0.0875 W/mK), establishing its potential as an effective insulation material for tropical microclimate. Good correlation between experimental and predicted strength (up to R2 = 0.976 and Pearson's r = 0.988) was obtained and the sensitivity analysis was used to analyze the influence of input parameters on the ANN prediction. The research contributes to the achievement of Sustainable Development Goals (SDG 3, 9, 11, 12) as it aims to convert agricultural waste into valuable building materials for green buildings in the humid tropics.Item DEVELOPMENT OF HYBRID MODELLING FRAMEWORK FOR FLOOD AND DROUGHT PATTERNS UNDER CLIMATE CHANGE VARIABILITIES IN RWANDA(Covenant University, Ota, 2026-08) IRAGUHA, Lionel; Covenant University, DissertationRwanda’s heavy reliance on rain-fed agriculture and its complex, steep topography renders it highly vulnerable to escalating climate-induced floods and droughts. Despite advancements in modern predictive technologies, the "black box" nature of traditional machine learning algorithms has significantly hindered their integration into practical policy making and water resource management. To address this gap, this dissertation develops and validates a novel hybrid modelling framework to analyze historical hydro-climatic trends (1981–2024), project future extreme scenarios up to the year 2100, evaluate socio-economic vulnerabilities, and formulate evidencebased adaptation strategies. The methodology leverages high-resolution Earth Observation Data (CHIRPS and ERA5-Land) alongside a bias-corrected CMIP6 Multi-Model Ensemble to force a SWAT-LSTM hybrid model. Within this framework, the physical SWAT+ model calculates the baseline water mass balance, while a Long Short-Term Memory (LSTM) deep learning network serves as a residual corrector to accurately capture non-linear routing processes and sub-daily temporal dependencies. Historical trend analysis reveals a severe "Temperature Penalty" across Rwanda, where the frequency of warm nights has doubled, dramatically elevating potential evapotranspiration (PET) and driving agricultural drought even in areas where annual rainfall volumes have recovered. Concurrently, the return period for 50-year extreme storm events in the Northern Province has contracted to just 5 years, frequently overwhelming existing municipal infrastructure. Through the integration of the LSTM network, the hybrid predictive model drastically outperformed standalone physical models, reducing the Root Mean Square Error (RMSE) by up to 74% and significantly improving the Kling-Gupta Efficiency (KGE) for discharge predictions. Future projections under the extreme SSP5-8.5 emission scenario indicate a critical "Precipitation Paradox". The model predicts a 15.9% acceleration in extreme flash flood peaks (reaching 250.80 m³/s) at the Ruliba catchment, severely threatening Kigali's urban infrastructure. In stark contrast, the downstream Rusumo catchment faces a +3.29°C temperature rise, generating an extreme evaporative demand of 1,460 mm annually that threatens the baseflow reliability of the Regional Rusumo Falls Hydroelectric Project and regional food security. To mitigate these geographically polarized hazards which are characterized by excess flood energy in the West and severe volume deficits in the East, the study proposes a "Spatial Rebalancing Philosophy". A Multi-Criteria Analysis (MCA) prioritized the construction of high-capacity Rainwater Harvesting (RWH) Catchment Dams, the deployment of LSTM-enhanced Dynamic Early Warning Systems, and the exploration of Induced Inter-Basin Water Transfers as the most effective adaptation measures. The successful execution of these strategies provides a data-driven blueprint to enhance Rwanda's climate resilience, actively supporting the National Strategy for Transformation (NST2) and directly aligning with the United Nations Sustainable Development Goals (SDGs 2, 6, 11, and 13).Item DEVELOPMENT OF A REGENERATIVE BRAKING MODEL USING MAMDANI FUZZY LOGIC CONTROL FOR BATTERY MANAGEMENT IN ELECTRIC VEHICLES(Covenant University, Ota, 2026-08) BELLO, Esosasere Victory; Covenant University, DissertationElectric vehicles are one of the key options on the pathway to sustainable mobility, however, optimising the energy efficiency of EVs is a central engineering challenge. One of the most promising methods for extending driving range to the battery onboard a vehicle is regenerative braking, which recycles kinetic energy when the vehicle brakes, but causes transient charging currents and power peaks for the BMS to manage safely. How and when the braking torque is applied to regeneration is thus a key control strategy in energy performance and battery health. This work presents and tests a full regenerative braking model with battery management for EVs based on a Mamdani fuzzy logic controller that was selected by a principle-based and evidence-based comparative screening that compared this controller with a Takagi-Sugeno alternative. Both drivers took the full 1180-second New European Driving Cycle (NEDC). The comparative screening results have shown that the Mamdani controller has lower total battery SOC depletion for the entire NEDC (0.65%) when compared to Takagi-Sugeno (0.70%), which makes it the controller used for the entire model. The selected Mamdani-controlled model was evaluated with regards to the measured engineering outputs and showed: a net consumption of battery energy of 292.5 Wh over the complete NEDC test; an estimated regenerative energy of 73 Wh (ca. 20% regenerative efficiency) over the whole NEDC test; armature current between 0–35 A; stable motor speed tracking of the NEDC reference profile in both the urban (0–680 s) and the extra-urban (681–1180 s) part of the test.Item DEVELOPMENT OF A POLYMERIC NANOCOMPOSITE MEMBRANE FOR MICROBIAL CONTAMINANT REMOVAL IN PHARMACEUTICAL WASTEWATER(Covenant University, Ota, 2026-08) Akinyemi, Akinnike Felicia; Covenant University ThesisOne of the characteristics of pharmaceutical wastewater is high microbial contamination, which poses a high risk to both the environment and public health. Conventional treatments are not designed for eliminating microbial contaminants, hence the need for the development of advanced and sustainable membrane technologies. Therefore, this study aims to develop and evaluate the performance of PLA/PEG/CS/TiO₂ nanocomposite membranes for microbial removal in pharmaceutical wastewater. The membrane synthesis was achieved via phase inversion and subsequently evaluated through experimental and computational methods. Optimisation of membrane composition using Response Surface Methodology (RSM) identified a blend of 2 g of PEG, 0.2 g of chitosan, and TiO₂ as the optimal blend, producing a maximum microbial removal efficiency of 85.1% for sample C. The optimise membrane (M14) achieved a microbial reduction of up to 88.9% within 10 minutes for sample A wastewater, outperforming M2 and M3. Modelling of the filtration process using COMSOL Multiphysics provided predictive insights and mechanistic understanding that complemented experimental findings. Comparison with experimental data indicated that the model captured the general fluctuating behaviour of the filtration system, supporting its use for mechanistic insight and preliminary process understanding. Evaluation of the 20 fabricated membranes (M1-M20) shows that M14 with 2 g of PEG and 0.2 g each of TiO₂ and chitosan exhibited desirable properties, such as a rough, porous structure and strong -OH/-NH functionality. These properties enhanced the surface hydrophilicity and microbial adsorption. Performance testing revealed that M14 maintained the highest flux (4160 L/m²·h for distilled water; 3388 L/m²·h for wastewater), permeability (21,577 mL/(m²·s·bar)) and fouling resistance (Rf = 576,318 m⁻¹), while sustaining a flux recovery ratio above 70 % before irreversible fouling was observed at cycle 6. Adsorption studies show that the microbial rejection from M14 portrays a predominantly multilayer adsorption behaviour, which agrees with the Freundlich model with a linear plot and R2 of 0.997. Overall, the study successfully synthesised a multifunctional, biodegradable nanocomposite membrane with excellent antimicrobial performance and structural stability. The integration of experimental results with COMSOL modelling provided a mechanistic understanding and predictive framework for optimising nanocomposite membrane design. The fabricated membrane demonstrates strong potential for sustainable pharmaceutical wastewater treatment, combining eco-compatibility, high removal rejection, and stable performance under realistic operating conditions. Future work should focus on pilot/industrial-scale validation, long-term membrane fouling and stability studies, techno-economic assessment, and quantitative refinement of the COMSOL Multiphysics model.Item COMPARATIVE CO-PRODUCTION OF PECTIN AND BIOCHAR FROM PLANTAIN AND BANANA PEELS USING BOX-BEHNKEN DESIGN-BASED PROCESS OPTIMIZATION AND CHARACTERIZATION(Covenant University, Ota, 2026-06) EFEONAH, EMMANUEL OKEOGHENE; Covenant University DissertationAgricultural fruit peel wastes represent an abundant biomass resource with significant potential for value addition through integrated biorefinery approaches. However, comparative information on the simultaneous recovery of pectin and biochar from plantain and banana peels under optimized processing conditions remains limited. This study comparatively investigated the co-production of pectin and biochar from plantain and banana peels using a Box–Behnken Design for process optimization and characterization. A three-factor, three-level Box–Behnken Design comprising 17 experimental runs was employed to evaluate the effects of extraction pH (1.5–2.5), temperature (70–90°C), and extraction time (60–120 min) on pectin yield. Pectin was extracted using citric acid, precipitated with ethanol, and characterized for its physicochemical properties, while the residual biomass was carbonized at 550°C for 90 min in covered ceramic crucibles under restricted-oxygen conditions to produce biochar. Response Surface Methodology and analysis of variance showed that extraction conditions significantly influenced pectin recovery from both feedstocks. Numerical optimization predicted optimal extraction conditions of pH 2.277, temperature 84.43°C, and extraction time 107.35 min, corresponding to pectin yields of 9.496% for plantain peels and 6.577% for banana peels, with an overall desirability of 1.000. Experimental validation produced pectin yields of 9.0% and 6.0%, confirming satisfactory agreement between predicted and experimental responses. Physicochemical characterization of the representative pectin sample yielded an equivalent weight of 307.7, methoxyl content of 11.63%, and degree of esterification of 42.61%, confirming the production of low-methoxyl pectin. The produced biochars exhibited BET surface areas ranging from 185.97 to 282.75 m² g⁻¹ and average pore diameters of 4.69–4.86 nm, indicating predominantly mesoporous structures, with sample P5 exhibiting the most favourable textural characteristics. Overall, the study demonstrates that plantain and banana peels are promising feedstocks for co-producing pectin and biochar, thereby supporting sustainable biomass valorization and the development of a circular bioeconomy.Item INVESTIGATION OF POST-WELD HEAT TREATMENT EFFECTS ON SIMILAR AND DISSIMILAR LOW-CARBON AND STAINLESS-STEEL WELDMENTS(Covenant University, Ota, 2025-05) FASUYI, AKINBAYONLE AYOMIDE; Covenant University, ThesisThis study investigated the effect of post-weld heat treatment (PWHT) on the mechanical properties and corrosion behaviour of dissimilar metal (DM) weldments of carbon steel and AISI 304 austenitic stainless steel, as well as similar metal (SM) stainless steel-to-stainless steel weldments. PWHT of the specimens was performed at three temperatures (900⁰C, 1000⁰C, and 1100⁰C), along with an as-welded control. Tensile testing, weight-loss corrosion measurement, corrosion-rate determination, and Vickers microhardness profiling were conducted, and a two-way analysis of variance (ANOVA) was used to determine the statistical significance of the effects of material type and treatment temperature. The findings showed that the tensile strength of the two types of welds was similar, at about 240 MPa in the as-welded condition. Following PWHT, SM welds exhibited a significantly greater improvement, with a maximum ultimate tensile strength of 466 MPa at 1000⁰C, compared to 321 MPa in DM welds at the same temperature. ANOVA confirmed highly significant effects of material type, temperature, and their interaction on tensile performance. The corrosion analysis showed that DM welds had much higher weight loss and corrosion rates than SM welds in all conditions, with material type identified as the dominant controlling factor. Raising the PWHT temperature progressively reduced corrosion in DM welds, with 1100⁰C yielding the greatest effect. Hardness profiling showed that PWHT reduced peak fusion-zone hardness and enhanced distribution uniformity in both weld types, but DM welds consistently exhibited asymmetric softening attributable to compositional mismatch at the weld interface. The results indicate that 1000⁰C is the optimum PWHT temperature for tensile performance and that SM weldments outperform DM weldments under all tested treatment conditions.Item Thermodynamic and Adsorption Influence on the Corrosion Inhibitive Performance of Pawpaw Seed on A36 Mild Steel in 1 M H2SO4 Medium(2021) Ayoola, Ayodeji Ayodele; Fayomi, O. S. I.; Agboola, Oluranti; Durodola, B. M.; Adegbite, A. O.; Etoroma, A. A.This research work investigated the corrosion inhibitive performance of the nano-sized pawpaw seeds on A36 mild steel in 1 M H2SO4 medium. The metal samples were subjected to corrosive environment (with and without varied concentrations of the inhibitor) using both the weight loss and potentiodynamic polarization tests at different temperatures (278.15–318.15) K for weight loss and (30.15–323.15) K for potentiodynamic polarization study). The equipment used include Thermo scientific ARL OP-TIM’X 166 spectrometer (for metal composition analysis) and Autolab PGSTAT 302 N (for potentiodynamic polarization test). The results obtained showed that the nano-sized pawpaw seed is an effective organic inhibitor with optimum inhibitor concentration of 4 g/cm3 having inhibitor efficiency of 92% from the weight loss test. The inhibition performance of pawpaw seed increased with decrease in temperature for both the gravimetric tests (between 278.15 K and 318.15 K) and potentiodynamic polarization study (between 300.15 K and 323.15 K). The Langmuir adsorption isotherm with correlation coefficient (R2) of 0.99 accurately predicted the adsorption mechanism of the inhibitor on the metal surface. The thermodynamic change in Gibbs free energy (ΔGads) of (-12.9544 to -11.5409) kJ/mol and adsorption equilibrium constant ( Kads) of (1.70–2.99) of the adsorbed inhibitor on metal surface revealed both the spontaneous and physisorption nature of the inhibitor-adsorbed process. Also, the tafel plot showed that the inhibitor acted as a mixed-typed inhibitor.