Faculty of Engineering and Technology

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2D Flow around a Rectangular Cylinder: A Computational Study
(AFRREV STECH: An International Journal of Science and Technology, 2013-01-01) A.S., Olawore; I.F., Odesola
The unsteady flow around a rectangular cylinder is an area of great research for scientist for several years. A two-dimensional unsteady flow past a rectangular cylinder has been investigated numerically for the low Reynolds numbers (flow is laminar). Gambit has been used throughout this work to generate the geometry and meshes and the computational fluid dynamics analysis is done using fluent software. The influence of vortical structure and pressure distribution around the section of rectangular cylinders are examined and reported. The integral aerodynamic parameters are also reported. Strouhal numbers for Reynolds numbers of 55, 75, 100, 150, 250 and 400 are 0.102, 0.122, 0.129, 0.136, 0.139 and 0.158 respectively. The magnitudes of the coefficient of drag for the Reynolds numbers are 1.565, 1.524, 1.432, 1.423, 1.526 and 1.545. The lift coefficient for flow around a rectangular cylinder with a chord-to-depth ratio equal to 5 of low Reynolds numbers of 55, 75, 100, 150, 250 and 400 are 0.067, 0.101, 0.157, 0.212, 0.404 and 0.537 respectively. The pressure drags obtained in the simulations at zero angle of incidence are 1.446, 1.455, 1.439, 1.412, 1.579 and 1.602 for Reynolds numbers 55, 75, 100, 150, 225, and 250. The velocity across the rectangular cylinders varies from 0.089 to 1.02m/s. The forces caused by vortex shedding phenomenon must be taken into account when designing buildings for safe, effective and economical engineering designs.
3D Flow around a Rectangular Cylinder: a review
(AFRREV STECH, Vol. 1 (2) April-July, 2012, 2012-04-01) Odesola, Isaac F.; Olawore, Ayodeji
Turbulent flows around three-dimensional obstacles are common in nature and occur in many applications including flow around tall buildings, vehicles and computer chips. Understanding and predicting the properties of these flows are necessary for safe, effective and economical engineering designs. This paper presents the review of 3D flow around a rectangular cylinder using large eddy simulation as the turbulence model and the computational study is developed in the frame of the Benchmark on the Aerodynamics of a Rectangular Cylinder (BARC). Different simulations around bluff bodies were reviewed and the results obtained through different methodologies are presented. The effect of change by vortex shedding on the magnitude of fluid forces of rectangular cylinders are examined and reported. The aerodynamic integral parameters obtained from different papers are compared.
A BRIEF REVIEW OF CHARACTERISTICS AND APPLICATIONS OF SHAPE MEMORY ALLOYS IN ENGINEERING AND RELATED FIELDS
(International Journal of Mechanical Engineering and Technology (IJMET), 2021-09) Issa, W. A.; Camur, H.; Savas, M.
Shape Memory Alloys shortened as SMA’s are examples of smart materials. They sense and respond to changes in environmental conditions or stimuli, such as chemical, electrical, mechanical among others. This review, discusses the concept of SMA’s, including their engineering effects and innovations in SMA’s research. Similarly, the uses and applications of SMA’s in engineering and related fields such aerospace, biomedical, chemical, civil, electrical, and mechanical engineering are reviewed briefly including the merits and demerits of using SMA’s
A chi-square-SVM based pedagogical rule extraction method for microarray data analysis
(Institute of Advanced Engineering and Science (IAES), 2020) Salawu, Mukhtar Damola; Arowolo, Micheal Olaolu; Abdulsalam, Sulaiman Olaniyi; Isiaka, Rafiu Mope; Jimada-Ojuolape, Bilkisu; Olumide, Mudashiru Lateef; Gbolagade, Kazeem A.
Support Vector Machine (SVM) is currently an efficient classification technique due to its ability to capture nonlinearities in diagnostic systems, but it does not reveal the knowledge learnt during training. It is important to understand of how a decision is reached in the machine learning technology, such as bioinformatics. On the other hand, a decision tree has good comprehensibility; the process of converting such incomprehensible models into an understandable model is often regarded as rule extraction. In this paper we proposed an approach for extracting rules from SVM for microarray dataset by combining the merits of both the SVM and decision tree. The proposed approach consists of three steps; the SVM-CHI-SQUARE is employed to reduce the feature set. Dataset with reduced features is used to obtain SVM model and synthetic data is generated. Classification and Regression Tree (CART) is used to generate Rules as the Last phase. We use breast masses dataset from UCI repository where comprehensibility is a key requirement. From the result of the experiment as the reduced feature dataset is used, the proposed approach extracts smaller length rules, thereby improving the comprehensibility of the system. We obtained accuracy of 93.53%, sensitivity of 89.58%, specificity of 96.70%, and training time of 3.195 seconds. A comparative analysis is carried out done with other algorithms.
A Comparative Analysis of Complexity of C++ and Python Programming Languages Using Multi- Paradigm Complexity Metric (MCM)
(International Journal of Science and Research (IJSR), 2018-10-26) Balogun M. O.; Sotonwa K. A.
Software complexity metrics have used to quantifydifferent types of software properties such as cost, effort, time, maintainability, understanding and reliability. The existing metrics considered limited factors that affect software complexity, but do not consider the characteristics that affect complexity of multi-paradigm languages. In this work, a Multi-paradigm Complexity Metric (MCM) for measuring software complexity was developed for multi-paradigm codes. Multi-paradigm languages that were considered in thiswork are C++ and Python, these two languages combine the features of procedural and object oriented paradigms, therefore this research began with investigation of factors that affect the complexity of procedural code and object oriented code, so that the developed metric could be used not only for procedural code, but also either object oriented codes or in more general for multi-paradigm codes. The developed metric was then applied on sample programs written in most popular programming languages such as Python and C++, and the result of the developed metric was further evaluated with other existing complexity metrics like effective line of code (eLOC), cyclomatic complexity metric and Halstead complexity measures. The study showed that the developed complexity metric have significant comparison with the existing complexity metrics and can be used to rank numerous programs and difficulties of various modules.
A Complexity Metric for Multi-Paradigm Programming Languages
(International Journal of Emerging Technology and Advanced Engineering, 2014-04-22) Olabiyisi S. O.; Omidiora E. O.; Balogun M. O.
Software complexity metrics are used to measure variety of software properties such as cost, effort, time, maintenance, understanding and reliability. Most of the existing metrics considered limited factors that affect software complexity, but do not consider the characteristics of multi-paradigm languages. In this work, a Multi-paradigm Complexity Metric (MCM) for measuring software complexity was developed for multi-paradigm codes. Multi-paradigm languages that were used in this work combine the features of procedural and object oriented paradigms, therefore this research began with investigation of factors that affect the complexity of procedural code, thereafter with a more modern approach, the research was further extended by adding object oriented features, so that the developed metric could be used not only for procedural code, but also either object oriented codes or in more general meaning for multi-paradigm codes. The developed metric was then applied on sample programs written in most popular programming languages such as Python, Java and C++, and was further evaluated with other existing complexity metrics like effective line of code (eLOC), cyclomatic complexity metric and Halstead complexity measures. The study showed that the developed complexity metric have significant comparison with the existing complexity metrics and can be used to rank competitive programs and difficulties of various modules.
A Control Model of the Operating Head Dynamics of Jebba Hydropower System.
(Nigerian Journal of Technological Research (NJTR), 2019) Ogunbiyi O., Thomas C., Omeiza I. O. A. , Akanni J., Olufeagba B. J.
Electricity availability in Nigeria has been very poor over the years, underscoring the need for a better approach for managing generating resources. This paper presents the development of a dynamical model of the operating head of Jebba hydroelectric power plants for system studies and control system design. The mathematical model of the plant was developed from flow continuity conditions, some model parameters were obtained from the source while others were estimated from observations and analysis of the measured data. The developed dynamical equation was validated by comparing the response produced with values obtained by measurement. Upon integrating the model equation in the Microsoft EXCEL VBA® environment, a deviation of 2% from measured values was observed. Operators can therefore use the model as a decision support system, while control engineers can find the model directly applicable for optimal and robust control system design for the station.
A Direct Optimal Control of the Jebba Hydropower Station
(2nd International Conference of the IEEE Nigeria Computer Chapter, NigeriaComputConf, 2019) Ogunbiyi, O., Thomas, C. T., Olufeagba, B. J., Madugu, I. S., Adebiyi, B. H., & Adesina, L. M.
The optimal power generation from the Jebba hydroelectric power station is subject to the reservoir operating head, weather-related factors, units’ availability and system dynamics. In this paper, a computer control system is designed to ensure safe operation and maximize power generation. The controller is an optimal controller, which determines the amount of inflow required to regulate the reservoir operating head. The control law is an optimal control procedure developed around the steepest descent and conjugate gradient algorithm. The algorithms determine the control signal and state trajectories for the minimization of a performance index defined for the regulation of the reservoir operating head. The results show that the two techniques are feasible in estimating an optimal inflow needed to move the reservoir operating head from any level to the nominal head. The two techniques were compared under different operating conditions of the hydropower system, the conjugate gradient algorithm performs better in terms of computational time. The control algorithm is recommended for use in the realization of a computer control system for the station.
A Method of Colour-Histogram Matching for Nigerian Paper Currency Notes Classification
(Jordan Journal of Electrical Engineering (JJEE), 2023) Omeiza, I. O. A., Ogunbiyi, O., Ogundepo, O. Y., Otuoze, A. O., Egbune, D. O., & Osunsanya, K.
In this paper a new algorithm for the classification of three Nigerian paper currency notes, namely 200, 500, and 1000 Naira (N) denominations is presented. The work examines the effectiveness of using only colour histograms to differentiate between the classes or denominations of the three Nigerian paper currency notes. The bin-heights of the histograms of the HSI component images for the paper currencies are used as features while a rule-based classifier designed to take advantage of the changes or variations in the histogram patterns is used to classify the paper currencies into the right denomination class. The algorithm involves the utilization of a simple and effective comparison strategy as opposed to the existing, too-rigid metrics for histogram-comparison used by other authors for color indexing in content-based image retrieval systems. Over a testing data-set of 300 samples, the algorithm achieved an average classification accuracy of 98.66%, and classification accuracies of 100%, 99% and 97% for the N=200, N=500 and N=1000 denominations, respectively. The proposed algorithm does not require extensive preprocessing of the paper-currency images and as such is fast in implementation.
A Modified COST-231-Hata Path Loss Model for Typical Semi-Urban Environments in Nigeria
(KIU Journal of Science, Engineering and Technology, 2024) AKANNI, Jimoh, ISA Abdurrhaman Ademola, OGUNBIYI Olalekan, OLUFEAGBA Benjamin Jimmy
Outdoor path loss propagation modeling is critical in the planning and design of the coverage area by the Global System for Mobile Communication (GSM). For the best prediction of GSM signal at any location within its coverage region, an accurate forecast based on critical characteristics and a mathematical model is necessary. Multiple studies on path loss propagation model prediction for GSM networks conducted at various semi-urban environments in Nigeria proclaimed that propagation path loss models may provide different results when utilized in environments other than those in which they were initially designed, that car drive-test methodology was used during the data collection, and that COST-231-Hata model provides closet prediction to the practical measure values. This paper created an appropriate path loss model based on the COST-23-Hata model and outdoor measurement at 1800 MHz frequency range for the semi-urban area of Kwara State, Nigeria. The created model was used and validated with the measured data and COST-231-Hata model at other different semi-urban environments in Nigeria. The results analysis shows that the created model performed satisfactorily given the closet path loss prediction to the practical measure path loss values at all the study locations. It also gives the lowest Square Root Means Error (SRME) and Standard Deviation (SD) in all the base stations that were tested in semi-urban environments. The newly created model would therefore be more appropriate for GSM 1800 network design and installation in semi-urban environments in Kwara State, Nigeria, as well as any other semi-urban locations in Nigeria.
A Nonlinear Control Model and Operational Support System for the Kainji Hydroelectric Power System
(2019) Ogunbiyi, O., Thomas, C. T., Omeiza, I. O. A., Akanni, J., & Olufeagba, B. J.
Over the past years, the hydropower model and control were largely based on classical and linear transfer functions, this was motivated by the available control system design techniques that were available and the desire to simplify the design procedure. Such a model is inadequate for dynamic study and design of hydropower stations in the presence of uncertainties in the water head, discharge rate, elastic water effect, travelling wave effect, large variation power output and frequency. This research, therefore, focuses on developing a nonlinear model for the Kainji hydroelectric power station. The model relies on the energy conversion principles, inflows, discharge, evaporation rate and number of units on the busbar. The parameters of the model were also estimated, and the model was validated with an error within +1.4% to -3.6%. The model is expected to be used to determine the optimal control policies for the operation of the station and the release of water to downstream.
A Nonlinear Control Model and Operational Support System for the Kainji Hydroelectric Power System.
(Nigerian Journal of Technology (NIJOTECH), 2019) Ogunbiyi, O., Thomas, C. T., Omeiza, I. O. A., Akanni, J., & Olufeagba, B. J.
Over the past years, the hydropower model and control were largely based on classical and linear transfer functions, this was motivated by the available control system design techniques that were available and the desire to simplify the design procedure. Such a model is inadequate for dynamic study and design of hydropower station in the presence of uncertainties in the water head, discharge rate, elastic water effect, traveling wave effect, large variation power output and frequency. This research, therefore, focuses on developing a nonlinear model for the Kainji hydroelectric power station. The model relies on the energy conversion principles, inflows, discharge, evaporation rate and number of units on busbar. The parameters of the model were also estimated, and the model validated with an error within +1.4% to -3.6%. The model is expected to be used to determine the optimal control policies for the operation of the station and the release of water to the downstream.
A POSTGRADUATE WORKS EXPERIENCE REPORT TO THE NIGERIAN SOCIETY OF ENGINEERS
(2014) Amoloye, Taofiq Omoniyi
I prepared this 47 page report in partial fulfilment of the requirements for admission into the corporate membership of the Nigerian Society of Engineers and towards the goal of registration with Council for the Regulation of Engineering in Nigeria. Corporate membership of the Nigerian Society of Engineers is only attained after passing a series of thorough assessment including but not limited to an oral interview, a written examination and submission of a technical report. The report contains two volumes: Volume I which details my postgraduate experience; and Volume II which gives the details of the design and construction of a hot air balloon which I undertook between 2013-2014.
A Progressive Domain Expansion Method for Solving Optimal Control Problem.
(TELKOMNIKA (Telecommunication, Computing, Electronics and Control), 2020) Ogunbiyi, O., Ogundepo, O. Y., & Sani, M. I.
Electricity generation at the hydropower stations in Nigeria has been below the expected value. While the hydro stations have a capacity to generate up to 2,380 MW, the daily average energy generated in 2017 was estimated at around 846 MW. A factor responsible for this is the lack of a proper control system to manage the transfer of resources between the cascaded Kainji-Jebba Hydropower stations operating in tandem. This paper addressed the optimal regulation of the operating head of the Jebba hydropower reservoir in the presence of system constraints, flow requirements and environmental factors that are weather-related. The resulting two-point boundary value problem was solved using the progressive expansion of domain technique as against the shooting or multiple shooting techniques. The results provide the optimal inflow required to keep the operating head of the Jebba reservoir at a nominal level, hence ensuring that the maximum number of turbo-alternator units are operated.
A Refined Potential Theory for the Incompressible Un- steady Subcritical-Reynolds number Flows on Canonical Bluff Bodies
(Georgia Institute of Technology, 2020-11-19) Amoloye, Taofiq Omoniyi
The three main approaches to exploring fluid dynamics are actual experiments, numerical simulations, and theoretical solutions. In classical potential theory, the steady inviscid incompressible flow over a body can be obtained by the superposition of elementary flows with known analytical solutions. Analytical solutions can offer huge advantages over numerical and experimental solutions in the understanding of fluid flows and design. These advantages are in terms of cost and time consumption. However, the classical potential theory falls short of reconciling the actions of viscosity in an experimentally observed flow with the theoretical analysis of such a flow. As such, it is unable to resolve the boundary layer and predict the especially important flow separation phenomenon that results in the pressure drag experienced by a body in the flow. This has relegated potential theory to idealized flows of little practical importance. Therefore, an attempt is made in this thesis to refine the classical potential theory of the flow over a circular cylinder to bridge the gap between the theory and experimentally observed flows. This is to enhance the ability to predict and/or control the flows' aerodynamic quantities and the evolution of the wake for design purposes. The refinement is achieved by introducing a viscous sink-source-vortex sheet on the surface of the cylinder to model the boundary layer. These vortices, sources and sinks introduced at the cylinder surface are modeled as concentric at every location. The vortices are modeled as Burgers' vortices, and analytic expressions for their strengths and those of the sinks/sources are obtained from the classical theory. These are employed to obtain a viscous and time-dependent stream function that captures critical qualitative features of the flow including flow separation, reattachment, wake formation, and vortex shedding. After that, a viscous potential function, the Kwasu function, with which the pressure field is obtained from the Navier-Stokes equation, is derived from the stream function. It is obtained by defining the viscous stream function on a principal axis of the flow about which the vorticity vector is identically zero. Strategies have also been developed to account for the finite extent of the cylinder and dynamic unsteadiness of the flow, and to predict the points of separation/reattachment/transition and the boundary layer thickness. Additionally, the strategies are used to obtain forces and apply the solution to arbitrary geometries focusing on spheres and spheroids. These strategies include the gravity analogy that considers a fluid element-cylinder scenario to be like a two-body problem in orbital mechanics. This analogy introduces the perifocal frame of fluid motion and exploits it to resolve the d'Alembert's Paradox. The perifocal frame is also used to predict flow separation/reattachment/transition and explain the observation of sign changes in the shear stress distribution at the rear of a circular cylinder in a crossflow. The refined potential theory is verified against experimental and numerical data on the cylinder in an incompressible crossflow at freestream Re∞=3,900. Its drag prediction is within the error bound of measured data and tHRLES (transitional Hybrid Reynolds-averaged Navier-Stokes Large Eddy Simulation) prediction. The predictions of the pressure distribution, separation point and Strouhal number are also within acceptable ranges. Its prediction of the force coefficients over the range 25≤Re∞<300,000 is validated against experimental and theoretical data on the cylinder in crossflow. There is a good agreement in the magnitude and trend for Re∞>100. For Re∞<100, there is a disparity in magnitude that is unsafe for design purposes. Similarly, it under-predicts the coefficient of drag in some of the explored axial flow configurations. However, at Re∞=96,000 and an aspect ratio of 2, the RPT drag prediction falls within 1.2% of validated computational result. The energy spectra of the wake velocity display the Kolmogorov's Five-Thirds law of homogeneous isotropic turbulence. This verifies and validates the unsteadiness in refined potential theory as turbulent in nature. The drag coefficient of a sphere for 25≤Re∞< 300,000 is explored to demonstrate the application of refined potential theory. Additionally, the flow over a sphere at Re∞=100,000 is explored in detail. A generally good agreement is observed in the prediction of the experimental trend for Re∞≥2,000. The transitional incompressible flows over a 6:1 prolate spheroid at an angle of attack β=45° for Re∞=3,000$ and Re∞=4,000 are also explored. The present theoretical pressure distribution has a close agreement with the DNS (direct numerical simulation) result in the starboard rear of the spheroid. However, the magnitude of the predicted force coefficients are generally less than five times the corresponding DNS results. The asymmetry of the DNS pressure distribution in the meridian plane is not captured. Therefore, further analyses of the spheroid flow including the separation locations are recommended for further studies. It is concluded that the refined potential theory can be used to resolve, explore and/or control the aerodynamic quantities of the flows around canonical bluff bodies as well as the evolution of their wakes.
A Refined Potential Theory for the Incompressible Unsteady Subcritical-Reynolds number Flows on Canonical Bluff Bodies
(2020-11-16) Taofiq O Amoloye
The three main approaches to exploring fluid dynamics are actual experiments, numerical simulations, and theoretical solutions. In classical potential theory, the steady inviscid incompressible flow over a body can be obtained by the superposition of elementary flows with known analytical solutions. Analytical solutions can offer huge advantages over numerical and experimental solutions in the understanding of fluid flows and design. These advantages are in terms of cost and time consumption. However, the classical potential theory falls short of reconciling the actions of viscosity in an experimentally observed flow with the theoretical analysis of such a flow. As such, it is unable to resolve the boundary layer and predict the especially important flow separation phenomenon that results in the pressure drag experienced by a body in the flow. This has relegated potential theory to idealized flows of little practical importance. Therefore, an attempt is made in this thesis to refine the classical potential theory of the flow over a circular cylinder to bridge the gap between the theory and experimentally observed flows. This is to enhance the ability to predict and/or control the flows' aerodynamic quantities and the evolution of the wake for design purposes. The refinement is achieved by introducing a viscous sink-source-vortex sheet on the surface of the cylinder to model the boundary layer. These vortices, sources and sinks introduced at the cylinder surface are modeled as concentric at every location. The vortices are modeled as Burgers' vortices, and analytic expressions for their strengths and those of the sinks/sources are obtained from the classical theory. These are employed to obtain a viscous and time-dependent stream function that captures critical qualitative features of the flow including flow separation, reattachment, wake formation, and vortex shedding. After that, a viscous potential function, the Kwasu function, with which the pressure field is obtained from the Navier-Stokes equation, is derived from the stream function. It is obtained by defining the viscous stream function on a principal axis of the flow about which the vorticity vector is identically zero. Strategies have also been developed to account for the finite extent of the cylinder and dynamic unsteadiness of the flow, and to predict the points of separation/reattachment/transition and the boundary layer thickness. Additionally, the strategies are used to obtain forces and apply the solution to arbitrary geometries focusing on spheres and spheroids. These strategies include the gravity analogy that considers a fluid element-cylinder scenario to be like a two-body problem in orbital mechanics. This analogy introduces the perifocal frame of fluid motion and exploits it to resolve the d'Alembert's Paradox. The perifocal frame is also used to predict flow separation/reattachment/transition and explain the observation of sign changes in the shear stress distribution at the rear of a circular cylinder in a crossflow. The refined potential theory is verified against experimental and numerical data on the cylinder in an incompressible crossflow at freestream Re∞=3,900. Its drag prediction is within the error bound of measured data and tHRLES (transitional Hybrid Reynolds-averaged Navier-Stokes Large Eddy Simulation) prediction. The predictions of the pressure distribution, separation point and Strouhal number are also within acceptable ranges. Its prediction of the force coefficients over the range 25≤Re∞<300,000 is validated against experimental and theoretical data on the cylinder in crossflow. There is a good agreement in the magnitude and trend for Re∞>100. For Re∞<100, there is a disparity in magnitude that is unsafe for design purposes. Similarly, it under-predicts the coefficient of drag in some of the explored axial flow configurations. However, at Re∞=96,000 and an aspect ratio of 2, the RPT drag prediction falls within 1.2% of validated computational result. The energy spectra of the wake velocity display the Kolmogorov's Five-Thirds law of homogeneous isotropic turbulence. This verifies and validates the unsteadiness in refined potential theory as turbulent in nature. The drag coefficient of a sphere for 25≤Re∞< 300,000 is explored to demonstrate the application of refined potential theory. Additionally, the flow over a sphere at Re∞=100,000 is explored in detail. A generally good agreement is observed in the prediction of the experimental trend for Re∞≥2,000. The transitional incompressible flows over a 6:1 prolate spheroid at an angle of attack β=45° for Re∞=3,000$ and Re∞=4,000 are also explored. The present theoretical pressure distribution has a close agreement with the DNS (direct numerical simulation) result in the starboard rear of the spheroid. However, the magnitude of the predicted force coefficients are generally less than five times the corresponding DNS results. The asymmetry of the DNS pressure distribution in the meridian plane is not captured. Therefore, further analyses of the spheroid flow including the separation locations are recommended for further studies. It is concluded that the refined potential theory can be used to resolve, explore and/or control the aerodynamic quantities of the flows around canonical bluff bodies as well as the evolution of their wakes.
A SIMPLE SLOW-SAND FILTER FOR DRINKING WATER PURIFICATION
(Arid Zone Journal of Engineering, Technology and Environment, 2017-04) K. O. Yusuf, K. R. Adebayo and I. E. Onah
Water-borne diseases are commonly encountered when pathogen-contaminated water is consumed. In rural areas, water is usually obtained from ponds, open shallow wells, streams and rain water during rainy season. Rain water is often contaminated by pathogens due to unhygienic of physical and chemical conditions of the roofs thereby making it unsafe for consumption. A simple slow sand filter mechanism was designed and fabricated for purification of water in rural areas where electricity is not available to power water purification devices. Rain water samples were collected from aluminum roof, galvanized roof and thatched roof. The waters samples were allowed to flow through the slow sand filter. The values of turbidity, total dissolved solids, calcium, nitrite, faecal coliform and total coliform from unfiltered water through thatched roof were 0.92 NTU, 27.23 mg/l, 6 mg/l, 0.16 mg/l, 5cfu/100ml and 6.0 cfu/100ml, respectively while the corresponding values for slow sand filter from thatched roof were 0.01 NTU, 0.23 mg/l, 2.5 mg/l, 0.1 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values of turbidity, total dissolved solid, nitrite, calcium, faecal coliform and total coliform from unfiltered water for aluminum roof were 0.82 NTU, 23.68 mg/l, 2.70 mg/l, 1.0 mg/l, 4 cfu/100ml and 4cfu/100ml, respectively while the corresponding values for slow sand filter were 0.01 NTU, 0.16 mg/l, 0.57 mg/l, 0.2 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values obtained for galvanized roof were also satisfactory. The slow sand filter is recommended for used in rural areas for water purification to prevent risk of water-borne diseases.
A Steepest Descent Algorithm for the Optimal Control of a Cascaded Hydropower System
(International Journal of Electrical and Computer Engineering (IJECE), 2020) Ogunbiyi, O., Thomas, C. T., Ogundepo, O. Y., Omeiza, I. O. A., Akanni, J., & Olufeagba, B. J.
Optimal power generation along the cascaded Kainji-Jebba hydroelectric power system had been very difficult to achieve. The reservoir's operating heads are being affected by possible variations in impoundments upstream, stochastic factors that are weather-related, availability of the turbo-alternators and power generated at any time. Proposed in this paper, is an algorithm for solving the optimal release of water on the cascaded hydropower system based on the steepest descent method. The uniqueness of this work is the conversion of the infinite-dimensional control problem to a finite one, the introduction of clever techniques for choosing the steepest descent step size in each iteration and the nonlinear penalty embedded in the procedure. The control algorithm was implemented in an Excel VBA® environment to solve the formulated Lagrange problem within an accuracy of 0.03%. It is recommended for use in system studies and control design for optimal power generation in the cascaded hydropower system.
A Study of Energy Conversion at the Jebba Hydroelectric Power Station
(IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017) Thomas C. T., Akorede M. F., Ogunbiyi O., Olufeagba B. J., & Samuel S. J.
Hydroelectric power significantly contributes to the national power grid of Nigeria. This paper examined the extent of utilization of the energy supplied into each of the turboalternators at the Jebba Hydroelectric Power Station (JHEPS), Nigeria and suggests a corrective culture to be employed for improved efficiency. The basic principle of a hydropower scheme and its conversion considerations were highlighted. The daily discharge, Q, in cumecs and the power generated, P, in MW at JHEPS over a decade period (2005 – 2014) were analyzed using codes and scripts of Microsoft EXCEL-VBA. Jebba hydroelectric power station is one of the three major hydropower stations in Nigeria and the potential is just beginning to be exploited. The stochastic distribution pattern of the station is also presented for further analysis of failure and repair of the station. The conversion behavior of each unit was found to be linear and all have a value greater than 0.5 on a scale of 0.00 to 1.00. Turbo-alternator (TA) unit 1 was found to have the highest conversion characteristic of 0.9951, while unit 4 was the least at 0.6884. However unit 6 was exempted in this analysis as it was not in use during this period. The paper also gave an insight into the effective operating head of each TA, the paper also suggests the corrective measure to employ for each turbine.
Advances in utilization of carbon-dioxide for food preservation and storage
(Elsevier, 2023) Adeshina Fadeyibi
Utilization of carbon-dioxide (CO2) in post-harvest value chain is a subject of interest among stakeholders in the food industry. In this paper, current and future applications of the CO2, including food storage, animal stunning, skin tanning, blasting dry ice, and controlled storage atmosphere (CSA) were reviewed. The technique applies to quality preservation during food drying and inactivation of enzymes, like polyphenol oxidase, and lipoxygenase, which are accountable for the loss of color and flavor in beverages. It also applies to plant and animal management, including inspection and control of facilities, cleaning of skin products, and protection of cereals and horticultural crops against attacks by insects, pests, and microbes. However, it may not be appropriate for food transportation and retail storage due to the use of sophisticated facilities. Thus, a simplified equipment was recommended to facilitate management of the storage system. Also, it was suggested to investigate the influence of the dry ice pretreatment on microstructural properties, vibration loadings and rheological stability of the stored foods as a way-forward for further studies. A high-pressure CO2 technique was proposed for treatment of fouling in facilities used for food preservation and storage.

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