Nigerian Journal of Technological Development <p>The Nigerian Journal of Technological Development is now a quarterly publication of the Faculty of Engineering &amp; Technology, University of Ilorin, Ilorin, Nigeria. It publishes original high-quality articles focusing on all aspects of Engineering and Applied Sciences in March, June, September and December. Manuscripts are double-blind peer-reviewed and if found suitable, published according to the subject matter as a <strong>Research Paper, Review Paper or a Technical Note.</strong></p> <p>Other websites associated with this journal:&nbsp;<a title="" href="" target="_blank" rel="noopener"></a></p> en-US <p>In accordance with the Copyright Act of 1976, which became effective January 1, 1978, the following statement signed by each author must accompany the manuscript submitted: "I, the undersigned author, transfer all copyright ownership of the manuscript referenced above to the Nigerian Journal of Technological Development, in the event the work is published. I warrant that the article is original, does not infringe upon any copyright or other proprietary right of any third party, is not under consideration by another journal, and has not been published previously. I have reviewed and approve the submitted version of the manuscript and agree to its publication in the Nigerian Journal of Technological Development." A copyright transfer form may be downloaded from the NJTD Website ( Author(s) will be consulted, whenever possible, regarding republication of material. All authors must have access to the data presented and the authors and sponsor (if applicable) must agree to share original data with the editor if requested.</p> (Dr. M. F. Akorede) (Professor A. A. Adedeji) Wed, 22 Apr 2020 18:26:15 +0000 OJS 60 Evaluating the Stability and Adequacy of NIGNET for the Definition of Nigerian Geodetic Reference Frame <p>A set of Continuously Operating Reference Stations (CORS) distributed all over Nigeria constitutes the Nigerian GNSS Reference Network referred to&nbsp; as NIGNET. Global Navigation Satellite System (GNSS) is a system tha&nbsp; uses satellites for autonomous position determination, and is a critical&nbsp; component of the modern-day geodetic infrastructure and services. Using CORS provide geodetic controls of comparable accuracy and a better alternative to the classical geodetic network. As the NIGNET infrastructure is utilised for different geodetic applications, it has become necessary to evaluate the suitability of the network data for the definition of a geodetic reference frame (GRF). This study utilised the technique of Precise Point Positioning (PPP) in position estimation, and time series analysis for temporal monitoring of the network. The sufficiency and adequacy of the NIGNET data archive was also evaluated against that of an International GNSS Service (IGS) Station. The temporal stability of the station coordinates measured in terms of standard deviations varied between 10 mm and 22 mm. This analysis suggests a relative stability required for Tiers 1 and 2 CORS in line with the IGS standards. Based on this reported stability, it is concluded that NIGNET is fit for purpose in defining the Nigerian Geodetic Reference Frame. However, despite the good data quality observed, the adequacy of the network has been compromised by infrastructural failures and lack of continuity in data transmission. Accordingly, it is recommended that both practical and policy measures required to ensure the&nbsp; realisation of the goal of the network should be implemented.</p> <p><strong>Keywords</strong>: Geodetic reference frame, NIGNET, CORS, precise point positioning, temporal stability and adequacy. </p> E.G. Ayodele, C.J. Okolie, C.U. Ezeigbo, F.A. Fajemirokun Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Impact of Pavement Roughness on Traffic Safety under Heterogeneous Traffic Conditions <p>H ighway safety is a major priority for public use and for transportation agencies. Pavement roughness indirectly influence drivers' concentration, vehicle operation, and road traffic accidents, and it directly affect ride quality. This study focuses on analyzing the influence of pavement roughness on traffic safety using traffic, pavement and accident data on dual and single carriageway operated under heterogeneous traffic conditions in South-west, Nigeria. Traffic crash data between 2012 and 2015 was obtained from the Federal Road Safety Commission (FRSC) and International Roughness Index (IRI) data from the Pavement Evaluation Unit of the Federal Ministry of Works, Kaduna. Crash road segments represented 63 percent of the total length of roads. IRI values for crash and non-crash segments was a close difference of 0.3,This indicates that roughness is not the only factors affecting occurrence of traffic crashes but a combination with other factors such as human error, geometric characteristics and vehicle conditions. Crash severity was categorized into Fatal, serious and minor injury crashes. In all cases, the total crash rate increases with increase in IRI value up to a critical IRI value of 4.4 and 6.15 for Sagamu-Ore road and Ilesha-Akure-Owo road respectively, wherein the crash rate dropped. The conclusion is key in improving safety concerns, if transportation agencies keep their road network below these critical pavement conditions, the crash rate would largely decrease. The study concluded that ride quality does not directly affect traffic crash rate.</p> <p><strong>Keywords</strong>: Pavement conditions, traffic safety, International Roughness Index, crash rate, carriageway. </p> M.O. Popoola, O.A. Apampa, O. Adekitan Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Development and Performance Evaluation of Solar Photovoltaic Module’s Surface-to-Rear Temperature Controlled Valve for Cooling Application <p>This study investigated the effectiveness of the developed solar photovoltaic (PV) module's surface-to-rear temperature-controlled solenoid valves for PV module cooling application. The cooling fluid is regulated by energizing normally closed (NC) solenoid valve with control parameters as modules rear and surface temperatures. ATmega32 microcontroller was utilized as central processing unit with two (2) LM35 as input sensors and solenoid valve as an output device. Each of 2-LM35 temperature sensors were dedicated to measure module's rear and surface temperatures respectively. The measured temperature values were coded as controlled parameters for regulating cooling fluid discharge by energizing a NC solenoid valve. The system was observed to discharge cooling fluid by energizing the solenoid valve under module's surface and rear temperature difference of less than or equal to 1.5<sup>0</sup>C (Ts-Tr≤1.5<sup>0</sup>C). The module's mean surface temperatures of 49.31<sup>0</sup>C and 54.92<sup>0</sup>C were recorded for temperature-controlled PV cooling applications and a standard solar photovoltaic/thermal (PV/T) system. The maximum recorded surface temperatures for temperature-controlled PV cooling and a standard PV/T systems were 54.00C and 57.6<sup>0</sup>C respectively. The mean absorber temperatures of 45.51<sup>0</sup>C and 40.87<sup>0</sup>C were respectively recorded for temperature-controlled PV cooling and standard PV/T. The maximum absorber temperature recorded for temperature-controlled PV cooling and standard PV/T were 48.30<sup>0</sup>C and 41.63<sup>0</sup>C respectively. The solar cells temperature is reduced by 5.38% through solenoid valve temperature controlled solar module cooling application.</p> <p><strong>Keywords</strong>: Temperature-controlled, ATmega32, solenoid valve, solar module, cooling application.</p> M. Mawoli, H.N. Yayha, B.G. Danshehu, M.L. Muhammad, A.S. Bature Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Neural Network Prediction of P-wave Log for Reservoir Characterization in the Niger Delta Basin <p>This study present a new technique that integrates several logs for P-wave prediction to minimize some errors and uncertainties associated with most estimation methods. The adopted method involves application of an artificial neural network technique that integrates density, resistivity and gamma ray logs for data training and the prediction of P-wave log. The results obtained gave correlation coefficient of 0.77, 0.24 and 0.42 between the acquired P-wave log and the acquired density, resistivity and gamma ray logs respectively, to demonstrate the relationship between P-wave log and the selected logs for the prediction process. The correlation coefficient of the estimated P-wave from Gardner and Faust methods with the acquired P-wave log are 0.64 and 0.59 respectively, while that of the neural network derived P-wave gave a better correlation coefficient of 0.81. Cross plot validation of P-wave derive Acoustic Impedance against density for both lithology and fluid discrimination revealed clusters for neural network derived P-wave parameter similar to the acquired P-wave derived parameters. Results of the presented neural network technique have been demonstrated to be more effective than results of the two conventional techniques.</p> <p><strong>Keywords</strong>: Sonic log, Gardner’s method, Faust method, Neural network, Cross plot.</p> A. Ogbamikhumi, S.A. Salami, W.N. Uwadiae Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Dynamic Analysis of Series-Connected and Mechanically-Coupled Twin Synchronous Motor Drive <p>Series-connection of the stator windings of electric motors could serve a number of purposes, including load balancing between two synchronous motors. This paper modeled and analyzed a drive system of two separate three-phase synchronous motors whose stator windings are series- connected by a unique stator winding scheme, and whose shafts are mechanically coupled to a common load shaft through a speed reduction gear driven through the pinions of the respective motors. The mathematical model is developed in detail, and the system is simulated using MATLAB/SIMULINK. It is observed that for the case of a balanced load on the respective shafts of the two motors, the dynamic behavior of the two motors are identical. It is further observed that with the particular stator winding arrangement giving rise to six-windings per motor unit, each motor is essentially a three-phase motor and may be operated direct on line (DOL).</p> <p><strong>Keywords</strong>: Common load shaft; DOL; series-connected stator windings; synchronous motors, six-winding machine</p> I.K. Onwuka, G.C. Diyoke, E.S. Obe Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Effects of Temperature and Steeping Time on the Proximate Compositions and Selected Physical Properties of Soybean Flour <p>A study to investigate the effect of temperature (80, 85, 90, 95, and 100<sup>o</sup>C) and steeping time (12, 15, 18, 21, and 24 hours) on the proximate composition (ash, crude fibre, fat , protein, and carbohydrate) values (%) and physical properties (bulk density, packed density (g/ml), angle of repose (degrees), and particle size (μm)) on soybean flour was conducted. Response surface Methodology (RSM) was used for the work. Central Composite Design in Design Expert (version 6.0, 2002, Minneapolis, United States) computer software package was used to design the experiment. Analysis was also done and all results were presented with a three dimensional plot. The results showed that the moisture content of the soybeans flour ranged from 3.26 – 7.35, 3.40 – 4.50 for ash, 3.15 – 4.82 for crude fibre, 31.32 – 35.21 for protein, 19.37 – 22.65 for fat, and 29.66 – 35.19% for carbohydrate. Angle of repose for soybeans flour samples ranged from 33.15 – 38.16o, bulk density varied between 0.30-0.36, packed density varied between 0.52 – 0.57g/ml and particle size distribution varied between 0.44 – .98μm for the different samples. It was observed that longer steeping time and drying temperature resulted to an increase in the protein content and decrease in crude fibre content. Conversely shorter steeping time and lower drying temperature resulted in an increase in the fat content. A nine-point hedonic scale on sensory and acceptability tests showed that sample soaked for 24 hours and dried at 90<sup>o</sup>C was most preferred in taste and overall acceptability.</p> <p><strong>Keywords</strong>: Soybean flour; packed density; angle of repose; steeping time, temperature.</p> E.G. Ikrang, J.U. Okoko, M.M. Akwa Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Continuous Sorption of Chromium Ions from Simulated Effluents using Citric Acid Modified Sweet Potato Peels <p>Adsorptive removal of chromium ion in aqueous medium using activated sweet potato peel (SPP) was studied in a laboratory-scale fixed bed column. Specifically, the effect of process parameters such as bed depth, flowrate and chromium ion concentration in aqueous solution, on the adsorption efficiency of the acid modified sweet potato peel was examined. Column adsorption analysis showed that at the flow rate of 0.5 cm3/min, bed height of 6 cm and column influent concentration of 30 mg/dm3, the optimum chromium (VI) ion removal of 87.5% was attained with the equilibrium adsorption capacity of 2.4548 mg/g. Continuous adsorption models such as Yoon-Nelson, Adam-Bohart and the Bed-Depth Service Time (BDST) model, were used to analyse the experimental data and based on correlation coefficient, BDST model best aligned with the obtained experimental data with correlation coefficient, R2, value of 96.43%. The bed capacity, No, and the rate constant, Ka, were calculated as 4.259 mg/dm3 and 0.01045 L/mgmin respectively at optimum column conditions. Results confirmed that acid modified SPP can be used to remove or reduce concentrations of Cr (VI) ions to allowable limits before disposal into water bodies.</p> <p><strong>Keywords</strong>: Continuous sorption, chromium ions, sweet potato peel, kinetic isotherms, breakthrough curves</p> M.D. Yahya, C.V. Ihejirika, Y.A. Iyaka, U. Garba, A.G. Olugbenga Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Computational Schemes in the Design of Novel Materials for Energy Savings <p>The current demand for lightweight energy efficient materials in industries to help in addressing the current challenges faced in reducing green house gas emissions is one of the motivations behind innovative material design. This paper has tried to review in particular the importance of the hierarchical multiscale modelling strategy in the design of novel lightweight materials. It also highlights on one of the hierarchical multiscale modelling methodologies from ab-initio level to macro level in predicting macroscopic material behaviour and the impact this simulation strategy will have on the development of innovative materials. It highlights on the limitations of this modelling strategy such as: the unreasonable computational time associated with the relaxation of polymeric chains or entanglements as well as scale bridging approaches between low level and high level models which are areas of current research interest.</p> <p><strong>Keywords</strong>: Multiscale modelling, lightweight materials, energy-efficiency, scale bridging, length scale.</p> Ohunene Hafsa Aliyu Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000 Internal Microclimate: Cumulative Exergy Consumption in a Sandcrete and a Burnt Brick- Walled Structure <p>Current practices of planning and designing of buildings in Nigeria do not consider the thermal comfort, the building energy and exergy demand. There is a need for better understanding of exergy analysis to improve the quality match between building energy demand and supply. The aim of this study is to estimate the exergy consumption value for a hollow sandcrete and a burnt brick-walled structure in a tropical sub-region. The properties of the building were assessed, eQuest software was used to estimate the energy demand of the respective buildings and the exergy analysis was conducted using the exergetic factor of electricity. The cumulative exergy consumptions of the existing sandcrete-walled building, the modelled sandcrete and the burnt brick-walled building were found to be 246,074.4 MJ/year, 128,646 MJ/year, and 128,595.6 MJ/year respectively. The modelled sandcrete-walled building, as well as the burnt brick-walled building, were found to be 48% more energy efficient than the existing<br>building as a result of improving the airtightness of the building, reducing the solar heat gain, and utilizing extremely efficient systems. However, the exergy analysis suggested that the hollow burnt brick-walled building perform better than the hollow sandcrete-walled building.</p> <p><strong>Keywords</strong>:&nbsp; Building, electricity, energy, eQuest, exergy, sandcrete.</p> A.A. Ibrahim, A.A. Adedeji Copyright (c) Wed, 22 Apr 2020 00:00:00 +0000