Arid Zone Journal of Engineering, Technology and Environment (AZOJETE)
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Design of Photovoltaic-Wind-Diesel-Battery Hybrid Energy System: Perspective of Energy Management System for Stand Alone Power Solution
Get PDFDesign of Photovoltaic-Wind-Diesel-Battery Hybrid Energy System: Perspective of Energy Management System for Stand Alone Power Solutio
Application of Genetic Algorithm Based Optimal Placement of Static Var Compensator for the Nigerian 330 kV Electricity Grid Performance Enhancement
Get PDFPower supply-demand imbalance is one of the critical challenges bedeviling the electricity grid operation of a third world nation such as Nigeria. This has consequently led to the system’s poor voltage profile with its associated high-power losses. Many potent solutions have been proposed to address these problems; however, technological advancements favour the adoption and widespread use of a class of economic and fast acting solid-state controllers called flexible alternating current transmission systems (FACTS). This study, therefore, assessed the potential of an optimally placed static var compensator (SVC) via genetic algorithm (GA) in enhancing the performance of the Nigerian 330 kV, 28-bus electricity grid. The static power flow model of the system with and without SVC was analyzed using Newton-Raphson method and simulated in MATLAB R2020a environment. The system performance with SVC placed optimally using GA was compared with the first principle approach. The simulation results revealed that before compensation, the test grid had five buses namely Ayede, New-Haven, Gombe, Kano and Makurdi with voltage magnitudes of 0.926, 1.058, 0.906, 0.859 and 0.944 p.u., respectively, violating the acceptable voltage tolerance limit of 0.95≤Vi≤1.05p.u. The first principle-based compensation improved the voltage magnitudes of the critical buses on the test grid to 1.015, 1.008, 0.958, 0.995 and 0.975 p.u., respectively, while compensation via GA enhanced the voltage magnitudes to 1.05, 0.985, 1.038, 1.016 and 0.996 p.u. respectively. The grid’s total active and reactive line losses reduced from 181.479 to 149.786 MW and 145.323 to 125.161 MVAr, respectively with compensation from the first principle approach, whereas the values were minimized to 115.675 MW and 109.336 MVAr, respectively with the GA based compensation. The GA based optimal placement of SVC exhibited better enhancement characteristics on the considered Nigerian electricity grid than the first principle method
Crop Water use of Cowpea (Vigna unguiculata) under Deficit Irrigation in a Controlled Environment
Get PDFCowpea Vigna unguiculata was planted in a pot at a density of one per pot and placed in a greenhouse at the Department of Biological Sciences, University of Agriculture, Abeokuta. It was subjected to four water treatments. The treatments were as follows: No deficit irrigation, 25% deficit irrigation, 50% deficit irrigation and 75% deficit irrigation. The pots were weighed each day with a precision weighing scale of accuracy of 1g to determine the amount of water to be added to each treatment. Before the experiment, the physical characteristics of the soil, such as bulk density, were determined. Water was applied to the treatment weekly. The soil in the pots was at field capacity at the start of the experiment, and the amount of water to be applied to each treatment was based on the difference in weight at the end of the week and evaporated based on the above-mentioned water allocation. Some of the chemical characteristics of the irrigated water were also determined. The findings indicated that cowpea (Vigna unguiculata) plants were very sensitive to lack of soil water during the total growing season and the yield formation period. A minimal water use efficiency was observed with a 50% deficit irrigation method showing a more sensitive yield response factor Ky (0.269) than other treatments. This implies that 50% deficit irrigation treatment produces a better yield with minimal irrigation water
A Retrospect of Energy Demand and Potential of Sub-Saharan Africa: Leveraging Energy Deficit to Attain Clean Energy Hub Region
Get PDFThe lack of reliable energy access is a significant obstacle to the socio-economic progress of the Global South, particularly sub-Saharan Africa (SSA). This research explores the current energy demand and access situation, evaluated SSA's renewable energy (RE) potential, identifies barriers to RE development, and proposed strategies to overcome these challenges. The study emphasises the importance of establishing RE infrastructure for a sustainable energy transition and outlined necessary investments. With an impressive 11,000 gigawatts (GW) of exploitable generating capacity, RE has the potential to replace fossil fuels effectively in SSA. The dominant resources are solar (10 TW), hydro (350 GW), wind (110 GW), and geothermal (15 GW) energy. Challenges include high initial costs, limited financing access, grid integration issues, infrastructure deficiencies, regulatory frameworks, and resource variability. To address these challenges, the study suggests policy and regulatory reforms, expanded financing access, capacity building, and improved grid infrastructure. Overall, this research presents the energy deficit and RE potential in SSA as opportunities for the region to become a clean energy hub, requiring collaboration among governments, academic institutions, industry stakeholders, and international organizations
Adsorption Isotherms and Kinetics of Heavy Metals Removal from Tannery Effluent Using Composite Agricultural Waste as Adsorbent
Get PDFTannery waste waters are very complex and characterized by high content of organic, inorganic and nitrogenous compounds which include heavy metals. In this study, the adsorption Isotherm and kinetics of a composite adsorbent produced from the chemical activation of groundnut shell and rice husk were utilized as agricultural waste in the removal of Pb, Cr and Cd from tannery effluent. The experimental data were fitted to Langmuir, Freundlinch and Temkin isotherms, while the kinetics were studied using Pseudo-First-Order and Pseudo-Second-Order kinetic models. The results revealed that Langmuir isotherm model showed excellent fit to the experimental data for all the heavy metal adsorption onto Groundnut shell activated carbon (GR-AC). This can be seen from the high correlation coefficients R2. The Langmuir monolayer adsorption capacity (qm) value was found to be 9.81 mg/g (Pb), 5.72 mg/g (Cr) and 4.25 mg/g (Cd) respectively. The equilibrium adsorption capacity (qe) values calculated from the Second Order kinetics model agreed well with the experimental values for Pb and Cd. In addition, the First Order Kinetic rate constant decreased with increase in initial metal ion concentration. The excellent correlation between the calculated qe and experimental qe values and higher regression coefficient R2 shows clearly that the adsorption of these heavy metals onto GR-AC followed Pseudo-Second-Order kinetic model. Therefore, groundnut shell and rice husk can effectively be utilized as agricultural waste to produce a composite adsorbent to remove Pb, Cr and Cd from tannery effluent
Effects of Orientation on the Properties of Fan Palm Fibre Reinforced Sheet
Get PDFIn this research, the effect of orientation of the strength of fan palm fibre reinforced sheets was investigated. The material used was fan palm fibre whose length varies from 0.8 to 1.7m with an average bulk density of 1.133g/cm3, specific gravity of 0.46 and Moisture Content (MC) of 7.40%. And the mould used was a wooden mould of 300×300×9 mm. The fibre was soaked in both water and cement slurry for 24 hours and 7 days. Soil sieve analysis was carried out using ASTM standard and curing was done for 28 days. The percentage of fibre in the sampled reinforce sheet was between 1-3% at various orientations (0, 30, 60° and 2D). The properties examined were Water Absorption (WA), Compressive Strength (CS) and Flexural Strength (FS). Data analysis was done using Response Surface Methodology (RSM). The results showed that the reinforced sheets with long fibre of 1, 2 and 3% have WA of 5.76, 3.72 and 5.05% respectively. While those with short fibre of 1, 2 and 3% have 6.87, 7.36 and 7.75% respectively. The CS of the reinforced sheets of 1, 2 and 3% fibre at 0, 30, and 600 orientations were 6.9568, 8.0779, 7.2330; 3.2870, 6.6764, 7.355; and 3.0592, 5.3215, 3.9090 N/mm2 respectively and the FS results were also observed. The CS and FS of reinforced sheets at 00 and 300 fibre orientations seems to be the best.  
Strength Characteristics of Microbial Induced Calcite Precipitate/Cement Stabilized Laterite Blocks
Get PDFThis paper assesses the strength characteristics of microbial induced calcite precipitate/cement stabilized laterite blocks. To achieve this, the compressive strength of unmodified lateritic soil blocks, Bacillus coagulans calcite precipitate modified lateritic soil blocks, cement modified lateritic soil blocks as well as the combined effects of the Bacillus coagulans calcite precipitate and 5% cement stabilized lateritic soil blocks were determined. Bacillus coagulans bacteria was used as the bio calcination agent and ordinary Portland cement as the stabilizer. The B. coagulans was mixed at various concentrations using the McFarland standard and cement was replaced at 5% to 20% replacement levels after which the crushing strengths were determined considering various curing ages. The compressive strength increased at the various curing ages ranging from 0.9 N/mm2 to 2.0 N/mm2 at 7 days, 1.3 N/mm2 to 2.1 N/mm2 at 14 days, 1.5 N/mm2 to 2.15 N/mm2 at 21 days and 1.65 N/mm2 to 2.5 N/mm2 at 28 days for all the stabilized blocks with varying concentrations of B. coagulans suspension. The compressive strength of the cement stabilized laterite blocks increased with an increase in percentage of cement replacement, and also with increasing B. coagulans suspension density for stabilized microbial induced calcite precipitate (MICP) laterite blocks. The 5% cement stabilized MICP laterite blocks performed better than cement stabilized laterite blocks with 20% cement replacement. The optimum concentration was achieved at Bacillus coagulans suspension of 2.4 x 109 cell/ml and 5% cement replacement at 28 days curing age with compressive strength value of 4.2 N/mm2. Based on the study conducted, it is recommended that for production of laterite blocks, a quantity of 5% cement replacement for stabilization of laterite may be used in addition to Bacillus coagulans to produce stronger laterite block
Development of Glaucoma Detection System using CNN and SVM
Get PDFGlaucoma is an eye illness that began as a result of high intraocular pressure and resulted in total blindness at its advanced stage It is a chronic eye disease caused by the damage of the optic nerve found at the back of the eye and will lead to vision loss. Abnormality in the drainage system of the eye causes fluid buildup that excessively triggers pressure leading to optic nerve damage. The development of Glaucoma detection system using Convolutional neural network (CNN) and Support vector machine (SVM) has been extensively studied in recent years. Many studies have shown that CNNs can accurately detect glaucoma from fundus images, optic nerve head images, and other imaging modalities. To implement CNN and SVM techniques for glaucoma detection, the process typically involves data collection, preprocessing, feature extraction, model training, validation, and testing. MobileNetV2 model and combined SVM-CNN approach was introduced in the research. As The Glaucoma Detection System was constructed using the MobileNetV2 CNN architecture which integrates multiple architectural elements to achieve optimal classification performance. Pre-trained weights were employed from the image data set while transfer Learning with MobileNetV2 approach was applied to empower the model with strong feature extraction capabilities. Global Average Pooling layers were appended to the base architecture, followed by dense layers for classification. These dense layers utilized Rectified Linear Unit (ReLU) activation and Dropout regularization to enhance model generalization. As a result, a metric evaluations for detecting Glaucoma Eye disease using Mobile_NetV2 and SVM offered a mean sum of 75% accuracy, 92% precision, 55% recall, 84% AUC and 34% F1 score. In summary, while SVM excels in precision, MobileNetV2 demonstrates better recall, AUC, and overall balanced performance. The choice of model depends on the specific goals and priorities of the glaucoma detection application, such as whether avoiding false positives (precision) or detecting as many true positives as possible (recall) is more critical
Measurement of Background Ionizing Radiation Level and Dose Risk Around Nigeria’s First Oil Well, Otuabagi, Oloibiri Clan, Bayelsa State, South-South, Nigeria
Get PDFIndividuals who get exposed to radiation stand the danger of experiencing health problems such as skin burn, acute radiation syndrome, cardiac condition. Natural radiation chains exist in nature including oil and gas fields in the ground. Therefore, crude may contain natural radioactivity. In this study, the background ionizing radiation level around the immediate vicinity of Nigeria’s first oil well has been measured using the Radalert-100X, a potable radiation detector. The background exposure rate ranges from 0.0095 to 0.0155 mRh-1 with a mean of 0.0128 mRh-1. The absorbed dose rate calculated ranges from 82.65 to 156.6 nGyh-1 with a mean of 109.56 nGyh-1. The averages of the annual effective dose equivalent ranges from 0.101 to 0.192 mSvy-1 with a mean of 0.136 mSvy-1. The calculated averages of ELCR from the study area ranges from 0.359 x 10-3 to 0.670 x 10-3 with a mean of 0.476 x 10-3. From the evaluation made, the granite area around the well head, has the highest background ionizing radiation value and other parameters compared to results from the well head and the muddy area. Given the values recorded in the study, it is imperative to advise that appropriate precautions be taken, such as adhering to the ALARA principle, to shield the public from radiation related risks.  
Development of a Palm Nut Cracker with Spinning Disc Shell Separator.
No full textThis paper presents the design and evaluation of a palm nut cracker with a spinning disc separator. The machine has five units namely: the hopper, the cracking chamber, the separating unit made of a vibrating screen and a spinning disc, the collectors, and the drive unit. The machine was designed and fabricated using locally sourced materials, and it was tested and evaluated at two operating speeds (480 and 660rpm) with palm nuts at three moisture contents of 5, 10, and 12%, respectively. The kernel-shell mixture was separated using the spinning disc made of three different materials; mild steel, plywood, and jute fiber. At a constant feed rate of 50 nuts per second, the cracking unit achieved a maximum cracking efficiency of 94.52%, while the throughput capacity was 8.05 kg/hr at 660 rpm for nuts with a moisture content of 10%. The spinning disc constructed of mild steel had the highest separation efficiency of 69.2% and kernel purity of 90.69% for cracked mixture with 12% moisture content at 60 rpm.