LAUTECH Journal of Engineering and Technology (LAUJET)
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Techno-economic optimization of a standalone hybrid pv-diesel-battery system for rural electrification using genetic algorithm
Get PDFGrid extension is expensive and diesel-only generation has significant environmental downsides, making it difficult for rural Sub-Saharan Africa to obtain reliable access to electricity. The ideal stand-alone hybrid renewable energy system made up of photovoltaic (PV), diesel generator (DG), and battery storage system (BSS) for rural electrification is proposed by means of a case study of Ayeoba, Olode community, Osun State, Nigeria. After performing a detailed feasibility study using on-site weather and load data, a mathematical model for the hybrid system was developed. A genetic algorithm (GA) was then employed to fine-tune and implement the model in MATLAB R2021a to achieve the lowest Cost of Energy while achieving 0 LPSP and decreasing CO?. The optimal configuration of the PV-DG-BSS system yielded a Cost of Energy of $0.10/kWh, a Loss of Power Supply Probability of 0%, and a CO? emission reduction of 84.1905 kg/day. These results indicate that GA is a valid tool to improve hybrid energy systems for rural communities as a sustainable and cheaper solution when compared to traditional power sources. It contributes to clean energy access and a step forward for Nigeria in the achievement of United Nations Sustainable Development Goals (SDGs)
Synergestic effect of rice husk ash blended with cement on the stabilization of lateritic soil for road construction
Get PDFLateritic soils are widespread in tropical regions and are often unsuitable for direct application in road construction due to high plasticity and low strength. The extensive use of Portland cement for soil stabilization has raised concerns over rising construction costs and environmental degradation caused by CO? emissions. This study examined the effect of stabilizing lateritic soil using Rice Husk Ash (RHA) blended with Ordinary Portland Cement (OPC), focusing on highway engineering applications. Natural lateritic soil samples were collected and treated with varying blends of cement (5%, 10%, and 15%) and RHA (2% to 10%) by dry weight. Standard geotechnical tests including Atterberg limits, compaction, California Bearing Ratio (CBR), and Unconfined Compressive Strength (UCS) were carried out to evaluate improvements. Furthermore, the chemical and microstructural properties of RHA and treated soil were analyzed using X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Results showed a notable improvement in geotechnical performance. The liquid limit dropped from 31.5% to 25%, the plastic limit dropped from 29.2% to 25%, and the plasticity index declined from 3.5% to 0%. Maximum Dry Density (MDD) rose from 1.84 g/cm³ to 1.96 g/cm³, while Optimum Moisture Content (OMC) decreased from 7.95% to 10.81%. The unsoaked CBR value increased from 76% to 94%, and UCS improved from 186 kN/m² to 334 kN/m² at an optimal mix of 10% cement and 10% RHA. RHA-cement stabilization significantly enhances the geotechnical properties of lateritic soils. This eco-friendly approach is recommended for sustainable and cost-effective road construction
Beneficiation Consequence on the Influence of Potential Hydrogen Variation in the Froth Flotation of Farin-Lamba (Plateau State) Cassiterite
No full textThis study explores the influence of pH variation on the froth flotation performance of cassiterite ore obtained from the alluvial deposits of Farin-Lamba, Plateau State. Bulk ore samples were acquired via random sampling across the active mining site and subsequently homogenized to ensure uniformity. A 20 kg head sample was prepared, from which a representative 5 kg sub-sample was subjected to comminution and sieving. The processed material underwent chemical analysis, particle size distribution assessment, and beneficiation through froth flotation under controlled pH conditions. Initial analysis showed a tin oxide (SnO2) grade of 20.22%. Sieve analysis across various mesh sizes identified -180+125 µm fraction as the optimal liberation size, recording the highest assay value of 23.28% SnO2. Accordingly, sieve fractions -250+180, -180+125, and -125+90 µm were selected for flotation experiments conducted using a Denver D-12 mechanical agitator at 1200 rpm and gas flow of 0.5-1.0 m2/h. Experiments were carried out at pH 5, 7, and 9 to determine the best condition Farin-Lamba cassiterite to be beneficiated. Post-flotation analysis revealed that the highest SnO2 concentration of 65.62% was achieved at pH 9 within the -180+125 µm size fraction, indicating this condition as optimal for tin beneficiation from Farin-Lamba cassiterite
The Power System Stability Development and Application of Mathematical Model of Reactive Power Loss Index As A Measurement Of Voltage Stability in Nigerian Transmission System
No full textThe Nigerian power system faces growing challenges in maintaining voltage stability due to increased demand, insufficient reactive power reserves, and the complexity of modern grid operations. This study presents the development and application of a mathematical model known as the Reactive Power Loss Index (RPLI) for identifying critical (weak) buses suitable for reactive power compensation in the Nigerian 52-bus transmission network. The RPLI model, derived using the bus admittance matrix method, serves as a voltage stability indicator by quantifying reactive power loss distribution across load buses. The model was implemented in MATLAB R2021a, and the voltage stability of the network was evaluated under contingency conditions. The performance of RPLI was compared with two existing methods: Relative Electrical Distance (RED) and Fast Voltage Stability Index (FVSI), based on voltage magnitude, maximum loadability, reactive power loss, and transmission line charges. Results showed that RPLI accurately identified vulnerable buses and achieved a reduction in reactive power loss by 6.78% and active power loss by 0.76% during contingencies compared to base contingency conditions. These outcomes validate the RPLI as an effective and computationally efficient tool for optimal placement of Static VAR Compensators (SVCs) and enhancing voltage stability in power systems
Optimization of Polypropylene Dosage for Improved Rheological, Physical and Mechanical Properties of Agbabu Bitumen
Get PDFThe vast majority of road infrastructure deformations are irreversible. They shorten the lifespan of flexible pavements and add to road safety concerns. Viscoelasticity is required for natural bitumen to function as a binder in pavements. However, when exposed to climate and heavy loads, natural bitumen's ability to undergo elastic deformation reduces. Consequently, road researchers have focused on modifying bitumen using polymers and nanomaterials to enhance pavement performance. Polymeric bitumen is extremely sensitive to Polypropylene (PP) dosage. Excessive use of PP leads to high viscosity. This study examines the impact of PP doses on the physical, rheological, and mechanical properties of Agbabu natural bitumen. The bitumen was dehydrated and analyzed for conventional characteristics using established techniques. The purified material was treated with PP at varying dosages (1.5 - 6 wt percent), and a binary mixture of bitumen and PP was optimized using D-Optima experimental design and response surface approach. The result shows that the mechanical properties, flash, and softening points of the raw bitumen were enhanced after modification. However, the penetration point of the modified bitumen decreases while viscosity increases as PP dosage increased from 2 to 3.75 wt percent. Therefore, the optimum dosage of 2.75 wt percent PP is recommended
Performance evaluation of a motorized legume threshing machine
Get PDFGrain threshing and separation are important post-harvest unit processes because it reduces excessive wastage and adds values to farm produces amongst other benefits, thus the performance parameters of the legume threshing machine was determined experimentally. The effect of static coefficient of friction was on the Threshing Efficiency (TE), Separation Efficiency (SE), Grain damage and Machine throughput were determined. The study was carried out using a randomized design of three feed rates (FR): 10g/s, 15g/s and 20g/s, four surfaces (S) mild steel (MS), plywood (PLD), carpet (CPT) and Rug (RG) using cowpea (Vigna unguiculata) IT84S-2242 and soybean (Glycine max L) 1448-2E variety. The cleaning efficiency obtained for soybean samples was 96%, while threshing efficiency was 99%. For cowpea threshing and cleaning efficiencies were 97.44 and 97.16%, from carpet surface. Statistical analysis using (ANOVA) showed that impurity level and feed rate affected cleaning efficiency at both 1 and 5% significance, type of surface affected threshing percentage and broken seeds at 5% significance. Using carpet surface resulted in the highest cleaning efficiency, threshing efficiency, low grain damage and grain losses at 100 g batch weight. In conclusion, coefficient of friction could be utilized to increase separation efficiency of thresher, this would aid the development of appropriate technologies for legumes processin
An enhanced security algorithm using a hybrid data encryption technique for a distributed computing environment (DCE)
Get PDFThe Cyberspace has witnessed a surge in different form of attacks with the user now at the losing end. The need to improve the performance of the crypto system has necessitated the urge to develop systems that are almost impenetrable to attackers and improve the level of confidentiality of data transmissions over the network especially Distributed Systems. A lot of research has recently been conducted on several neural net-based encryption techniques using single-layer or multilayer perceptron models.Hybrid combination of conventional crypto system and Neural Crypto system has been discovered to be effective in curbing the incessant network data breaches. In this paper, a framework for the development of a hybrid data encryption system is presented. Some of the known techniques was analysed and the various steps for the development of the hybrid algorithm presented. Finally, this work developed an algorithm for an enhanced crypto system with the combination of IDEA (International Data Encryption Algorithm and Artificial Feed Forward Neural Network (AFFNN) Algorithms
Influence of stator tooth thickness on losses and efficiency of a double stator electric machine
Get PDFOwing to the significant impacts of the electric machine's structural dimensions on its output characteristics and values, the effect of stator tooth thickness and shape is considered in this study. Finite element analysis is employed in the predictions. The machine parameters considered are magnetic properties, efficiency, and losses. It is revealed that if the analyzed machine has unequal stator tooth thickness without a stator tooth tip, then the resulting magnetic properties and eddy current loss values would be high; however, with improved overall machine efficiency. Consequently, a similar machine configuration that has equal stator tooth thickness with a stator tooth tip would exhibit larger total loss and a corresponding lower overall efficiency. The predicted magnetic coercive force values of the machine with and without equal stator tooth thickness are: 1415.51 kA/m and 1505.92 kA/m, respectively. Again, the resulting total losses of the machine with and without equal stator tooth thickness are 19.71 Watts and 19.16 Watts, respectively. Moreover, the improved machine type with unequal stator tooth thickness generated an efficiency of 92.83 % against its counterpart, which produced a corresponding efficiency of 92.60 %
Unsteady aerodynamic performance of spiked and unspiked aloe vera-inspired aerofoils at low reynolds number
Get PDFThe increasing demand for Micro Aerial Vehicles (MAVs) and other low-speed aerial platforms has intensified the focus on optimizing aerofoil designs for low Reynolds number applications. This study presents a comparative analysis of the unsteady aerodynamic performance of aloe vera-inspired aerofoils, both spiked and non-spiked, at Reynolds number 1.5 × 105. By employing the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations alongside the Transition SST (four-equation) turbulence model, the research accurately characterizes the flow field and aerodynamic loads under dynamic conditions. The results indicate that the novel spiked aerofoil exhibits superior performance at all angles of attack, demonstrating delayed flow separation and enhanced lift coefficient and lift-to-drag ratios compared to the non-spiked aloe vera aerofoil
Design and simulation of a sustainable water distribution network in iseyin, southwestern nigeria, using epanet 2.0 hydraulic software : Design and simulation of a sustainable water distribution network in iseyin, southwestern nigeria, using epanet 2.0 hydraulic software
No full textEfficient water distribution systems ensure water quality and a reliable supply. In Iseyin, the existing water distribution networks are non-functional, despite recent population growth. This research thus designs and simulates a sustainable water distribution network for Iseyin town Southwestern Nigeria, using the Environmental Protection Agency Network (EPANET) 2.0 software to enhance water resources management. Climatic data such as temperature, precipitation, humidity, rainfall days, sunlight, and evaporation rate values were obtained from the Nigerian Meteorological Agency between 2014 - 2024. Population data were sourced from the National Population Commission and projected for 50 years using the geometric mean approach. Water samples from Atoori and Ajumoda reservoirs were analyzed for physico-chemical and bacteriological parameters. Water demand and Water Quality Index (WQI) were estimated. The water distribution network was simulated using EPANET software to compute demand, pressure, velocity, and headloss at 1:00, 12:00, and 24:00 hours. Annual climatic conditions revealed that temperature ranged from 23.90°C to 28.40°C, precipitation from 7.00 mm to 188.00 mm, humidity from 47% to 85%, rainfall days from 1 to 19, sunlight hours from 3.30 to 8.90, and evaporation from 9.21 mm to 17.19 mm. The projected population of 1,491,036 by 2052 yields a total water demand of 213,005,142.86 Lpd. WQI indicates that Ajumoda was moderately polluted in the rainy season but excessively polluted in the dry season, with WQI of 73.03 and 303.89, respectively. In contrast, Atoori was excessively polluted in both rainy and dry seasons, with WQI of 261.74 and 498.29, respectively. The simulated network at different times indicates that Atoori has greater fluctuations in demand, headloss, and pressure. This study emphasizes optimizing reservoirs, pressure regulation, and responsive network design to address variations