International Journal of Engineering Research in Africa

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EISSN : 1663-4144
Published by: Trans Tech Publications, Ltd. (10.4028)
Total articles ≅ 818
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Abel Adekanmi Adeyi, Mellisa Chinazom Uzoukwu, Lekan Taofeek Popoola, Adeyinka Sikiru Yusuff, Esther Bernard, , Adebayo Tajudeen Ogunyemi, Abubakar Hamisu
International Journal of Engineering Research in Africa, Volume 60, pp 15-28;

The presence of cadmium ions in the environment is dangerous to a human being because of its chronic and acute health syndromes such as hypertension, testicular atrophy, and skeletal fetus malformation. To eliminate cadmium ions from the environment, cheap, non-toxic, and environmental-friendly biosorbents, an alkaline impregnated adsorbent, were prepared in this study. Alkaline impregnated chicken feather biosorbents (AICFB) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis. The AICFB prepared was employed for the cadmium sequestration from simulated wastewater. AICFB quantity, cadmium ion concentration, and temperature are parameters with significant effects on the metal ion sequestration process. Models by Langmuir, Freundlich, and Redlich-Peterson were assigned to analyse the adsorption isotherms. Experimental data seem good with all tested models, and best with the Redlich-Peterson model. The maximum sorption capacity of AICFB toward cadmium ion was 122.07 mg/g as monolayer entrapment at pH 6.5, 0.1 g of AICFB, 120 minutes contact time, and 298 K. The linear pseudo-first-order and pseudo-second-order kinetic models were applied for the analysis of kinetic data. The pseudo-second-order model suitably describes the cadmium ion uptake by AICFB, indicating the chemisorption process. The prepared AICFB demonstrates efficient cadmium metal sequestration from aqueous environments.
Saif Al Omairi, , Marya Al Balushi
International Journal of Engineering Research in Africa, Volume 59, pp 151-173;

Electricity supply in Oman is very stable, however, power generation from gas turbines and fossil fuels, which are not environmentally friendly, contribute over ninety percent to the present power grid. Due to rapid development, the current power state of Oman is been over stretched. This is as a result of increased power demand, considering the size of the electricity network and the control strategies employed at different levels of the power system. Therefore, in order to keep pace with the recent development, it is paramount to integrate the current power grid of the country with smart grid technologies. Some of the benefits of employing smart grid technologies are; providing more reliable power, utilizing more efficient renewable power, employing a mix of energy sources, use of smart devices, mitigating carbon footprint, enabling the roadmap for electric vehicles, availing smart job opportunities, saving of energy via reduced consumption programs, improved customer services, accurate billings, detection of frauds and technical losses, increased competition, and levelling of the demand curve or peak reduction. This paper presents the dynamics of making the power grid of Oman smarter, based on the current power situation in the country. The paper addresses the penetration of smart grid technologies with the national power grid and also present an extensive review of power situation of Oman power system. Efforts were made to discuss the possible locations of wind and solar energy potentials, in the country, since they are the two commonly used and readily available renewable energy sources. There is no doubt that smart grid technologies like information and communication technology, data management, energy sales and smart metering strategies, would play a huge role in making the power grid smarter. In addition, some dynamic behavior of the power grid was analyzed considering the penetration of solar and wind energy, in the current power grid of Oman.
Abdelkhalik Eladl, Ossama B. Abouelatta, Magdy Samuel,
International Journal of Engineering Research in Africa, Volume 59, pp 1-18;

Recently, hydroforming was developed to address the emerging problems encountered by the conventional rigid tool-based deep drawing process. Hydroforming is a specialized type of die forming process, that uses a rigid die while the pressure provided by the liquid acts as a punch to shape the sheet metal. The current paper is directed to study the hydroforming process numerically and experimentally as a means for shaping aluminum alloy sheets based on the quality of product thickness variation and surface roughness. Moreover, it offered a comparative investigation of the experimental and numerical findings of this process. Therefore, thickness variation has been calculated numerically by designing a numerical model using Marc software which fits in large deformation simulation. On the other hand, thickness variation and surface roughness were measured experimentally along drawn cups and compared with the numerical results. The numerical results of thickness variation are matched with the experimental results. Furthermore, surface roughness was measured and compared before and after drawing at five regions. Since there is no contact between the upper side of a cup and any metallic parts, surface roughness depends only on the effect of plastic strain and was found to be increased in all regions.
Oluwafunso Oluwole Osaloni, Akshay Kumar Saha
International Journal of Engineering Research in Africa, Volume 59, pp 135-150;

This paper presents the investigative study on the Unified Power Quality Conditioner (UPQC) impact on Radial Distribution System (RDS). The architecture of Power Angle Controlled UPQC named Improved Unified Power Quality Conditioner (I-UPQC) was implemented in RDS. The problem of power loss, under-voltage, and reactive power burden on shunt inverters are the significant issues addressed in this study. The allocation of I-UPQC by placing it at each bus of the RDS one node at each iteration, excluding the swing bus, is studied by considering its impact on each bus of the radial network. The Power Loss Index (PLI) and Degree of Under Voltage Mitigation Node (DUVMN) values of all the buses are calculated analytically using distribution framework expressions of I-UPQC. Hence, the bus having the highest PLI value, and the minimum permissible node voltage is the most favourable. The determination of the candidate bus for I-UPQC was achieved by the load flow algorithm. The results obtained in this study on IEEE 33 and 69 bus system shows 3.9% and 4.2% power loss reduction respectively for both networks. Also, the minimum bus voltage was improved to 0.954 p.u. and 0.955 p.u. in each case for both networks, after the allocation of I-UPQC in RDS, compared to the base case. Consequently, the VA burden on shunt inverter was reduced by reactive power compensation of the series inverter. The results and simulation obtained in MATLAB / SIMULINK environment and discussion to support the concept developed are also presented. The results from the study confirmed that the concept of I-UPQC placement impacted the operation of RDS compared to the other connected UPQC model.
Oluwole A. Olawuyi, Mutiu Kareem, Kazeem Ishola, Raseed O. Bolaji, Olusola O. Fadipe
International Journal of Engineering Research in Africa, Volume 59, pp 19-28;

This study investigates the effects of waste glass as a replacement for fine and coarse aggregates on the strength properties of concrete. Fine waste glass (FWG) and coarse waste glass (CWG) were utilised to replace natural fine and coarse aggregates at replacement rates of 0%, 10%, 15%, and 20%, with a constant water-to-binder (w/b) ratio of 0.5 and a mix ratio of 1:1½:3 for M25 grade. The workability of fresh concrete mix was determined with the slump test. To assess the hardened characteristics of concrete, compressive and tensile strength tests were performed at 7, 14, and 28 days’ curing ages. The results show that the workability of concrete decreases as the FWG and CWG contents in the concrete mix increase. The 28-day compressive and tensile strengths of concrete increased by 28% and 16% respectively, with the replacement of up to 15% FWG and CWG, respectively compared to the control. However, the compressive and tensile strengths of concrete reduces with further replacement of fine and coarse aggregate with waste glass. The strength properties of concrete are improved at the optimum permissible level of 15% FWG and CWG, respectively, as a substitute for conventional fine and coarse aggregates. It was concluded that using waste glass as a constituent material in concrete production is a viable option for disposing of waste glass and lowering concrete production costs.
, Jonah Chukwuemeka Agunwamba
International Journal of Engineering Research in Africa, Volume 59, pp 239-262;

This study investigated the optimization of process parameters for adsorption of hexavalent chromium with activated carbons extracted from palm tree leaves of Nigerian origin. The effect of process parameters such as adsorbent dosage, initial chromium concentration, temperature, contact time, and adsorbent particle size was studied with the aid of Central Composite Design. The result showed that for the adsorbent dosage, initial concentration, temperature, contact time, and particle size, the optimum conditions were found to be 20 mg, 80 mg/l, 40° C, 40 minutes, and 1400µm, respectively. The actual and predicted values obtained were 72.96 % as well as 70.33 %, respectively, indicating a good correlation with a comparatively small variance of 2.66 %. The Langmuir isotherm showed an R2 of 0.981 and thereby showing better linearity when compared with the Freundlich isotherm. The result of the adsorption kinetics indicated that it was better described by the Pseudo-second order model. The overall adsorption process on the other hand showed an exothermic reaction with an enthalpy value of -18.707. The values of Gibbs free energy (∆G) at various temperatures also revealed a spontaneous reaction and a positive value of entropy. The results obtained showed that the adsorbent was effective in the adsorption of hexavalent chromium.
Solomon I. Adedokun, Olukorede M. Osuolale, Akindele C. Apata, Walied A.H. Elsaigh, Bolanle D. Ikotun,
International Journal of Engineering Research in Africa, Volume 59, pp 101-117;

The impact of admixture of both Ordinary Portland Cement (OPC) and steel slag was examined on the geotechnical properties of the lateritic soil, by conducting basic geotechnical tests: Particle size analysis, Consistency limits, Compaction, California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) on both the natural and stabilized soil samples and results were subjected to statistical analysis using 2-way ANOVA (Analysis of Variance) at 5% level of significance. The natural soil was classified as s A-7-6 and MH under standard soil classification systems. Addition of steel slag lowered the liquid limit (LL) and plasticity index (PI), while cement increased the LL and decreased PI of the lateritic soil, respectively. With increasing content of slag and cement, maximum dry density increased with the corresponding decrease in optimum moisture content. CBR and UCS of the stabilized soil increased substantially with increasing contents of slag and cement. Both steel slag and cement have statistically significant effects on the geotechnical properties of the lateritic soil. Hence, this soil can be stabilized with addition of 12% steel slag and 6% cement contents for its application as an improved subgrade material for light trafficked pavement. Keywords: Lateritic soil, steel slag, cement, stabilization, Index properties, strength indices.
Ifeanyi Emmanuel Kalu, Ericmoore Jossou, Emmanuel Kwesi Arthur, Simon Ja'Afaru, Edith Yohanna Ishidi
International Journal of Engineering Research in Africa, Volume 59, pp 89-100;

Oil shales have unstable mechanical and chemical properties, which makes their extraction for characterization and conventional mechanical testing uneasy and complex. Most often, mechanical property measurements are usually taken from core samples that are costly to extract and test using conventional testing methods. This paper presents a focused study carried out on oil shale cuttings obtained from the sidewalls of two different wellbore depths in the Niger Delta area of Nigeria. Using the X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) characterization techniques, the morphology of these shales was studied. The results obtained clearly showed the composition, bonding and variations in the morphology of the studied shale samples. Furthermore, the heterogeneity associated with these shales across varied depths were revealed. An efficient and less expensive technique compared to conventional testing methods, instrumented indentation testing (IIT) was carried out to obtain essential mechanical parameters of the shale specimen. These properties are important parameters in determining the hydrocarbon storage space of shale formations, wellbore stability, and optimization of hydraulic fracturing which is necessary for efficient drilling operations.
Peter Anuoluwapo Gbadega, Akshay Kumar Saha
International Journal of Engineering Research in Africa, Volume 59, pp 175-204;

This paper addresses the problems of control and energy management in micro-grid with the incorporation of renewable energy generation, hybrid storage technologies, and the integration of the electric vehicles (EVs) with vehicle to grid (V2G) technology. The adaptive model predictive control (AMPC) technique is used to optimize the charge/discharge of the EVs in a receding horizon manner in order to reduce operational cost in a renewable energy-based micro-grid. V2G systems integration can be a crucial element in the assurance of network reliability against variability in loads. In this context, the paper presents an AMPC algorithm for the optimization of a micro-grid coupled with a V2G system consisting of six electric vehicle charging stations. The proposed algorithm effectively manages the use of renewable energy sources, vehicles charge, energy storage units, and the purchase and sale of electric power to the external network. Two scenarios are investigated in this paper to examine the performance of the proposed controller to manage the renewable energy sources in the micro-grid system. The first case uses a load shifting mechanism to solve the charge management problem during a known interval of parking time. The second case introduces the EVs with V2G capabilities when connected with the micro-grid. In this case, the vehicle battery collaborates with the ESS of the micro-grid to maximize costs benefits and mitigate the intermittency of renewable generation. Furthermore, other benefits of V2G concepts, such as voltage and frequency control for the micro-grid stability, are investigated. Therefore, it is evident from the obtained results that the proposed control algorithm was able to effectively manage the renewable energy sources, energy storage units, vehicles charge, and the purchase and sale of electric power with the grid. Keywords: Adaptive model predictive control, Energy management system, Electric vehicles, Vehicle to grid technology, Grid reliability, Load shifting, Optimization problem and MATLAB/Simulink.
Djamel Edinne Gaagaia, Mustapha Bouakba, María Del Mar Barbero-Barrera, Layachi Abdelheq,
International Journal of Engineering Research in Africa, Volume 59, pp 43-55;

In this paper, ‎morphological, physico-chemical and thermal properties investigations‎ are carried out for a ‎novel ‎composite material reinforced by Washingtonia Filifera (WF) palm fibers using a 20 weight (wt) % loading rate. The experimental analysis by Scanning Electron Microscopy (SEM) shows the longitudinal roughness of the surface, which plays a very important role in the adhesion between the WF fibers and the High Density ‎PolyethylenE (HDPE) resin. FTIR tests of the composite (WF 20%/ HDPE) represent out of plane vibrations involving ring and CH2 symmetric bending in cellulose chain.‎ Thermogravimetric analysis (TGA) and Derivative thermogravimetric ‎(DTG) thermal analysis show a thermal stability at 210°C, 2.5% residual mass ‎and 745 °C maximum ‎temperature. X-Ray Diffraction (XRD) analysis shows that the ‎crystallinity index is 59.2%, with a size of ‎‎23 nm. Using tensile tests, a Young modulus of 858.6 MPa, ‎17% elongation and a maximum stress of 15 MPa ‎are found. The obtained characteristics of WF reinforced composite are better than those of Bamboo reinforced composites which has been proven to have characteristics superior to those of standard particleboard and medium density fiberboard used mainly in the construction industry.
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