Browsing by Author "Oke, S. A."

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Analysis of traffic inflow to a university campus in a developing country:a rescale range approach
(2007-10) Alabi, B.; Salau, T. A. O.; Oke, S. A.
"All over the world, there is an increasing enrolment level for university admissions in view of the ever-increasing benefits of earning university degrees. Thus, the high population of students in many universities, coupled with a high number of vehicles has made traffic control a challenge to University traffic managers. In this paper, the method of Resca1e Range Analysis (RRA) was used to estimate the Hurst Exponent Value (HEV) for the traffic inflow through the main entrance gate of a university as a control measure. Data from a university in the developing countries was collected and analysed. The number of vehicles that entered consecutively per five minutes was observed between 07:00 and 19:00 over a 144 count and 17 independent cases constructed between adjacent cases. Rescale Range Algorithm platform is then used for the data, and coded in FORTRAN Language. With a case made up of 128 consecutive five-minute dependent traffic inflow records, a total of 3348 vehicles entered the university community within the studied period while the average number of vehicles inflow per hour was 279. Average number of vehicles that entered per five minutes was 24. No vehicle entered between 13:25 and 13:30. For all cases, the estimated HEV range between 0.5742 and 0.6955. The computed average HEV was 0.6303, the coefficient of fitness (R2) for all cases range between 0.9552 and 0.9787, while the computed average value was 0.9680. The HEV greater than 0.5 estimated for all cases is an indication of positive con-elation called Persistent. It expresses the fact that there are extended periods in which the traffic inflow to the university community deviated from the long term mean. This information is useful for vehicle garage design. For reliable estimates of the average HEV for design purposes, the study period should be extended to a whole week or an academic session. "
The application of fractal box dimensions in predicting the emission characteristics of colliding sawdust particles for sustainable sawmilling
(CSIRO Publishing, 2012) Salau, T. A. O.; Oke, S. A.
"The prediction of emission characteristics of sawdust particles immediately after the cutting operation from the interaction of band saw's blade and plank is a growing research area. Still, a wide gap exists with respect to understanding the behaviour of sawdust particles as they collide with one another. Previous efforts have focused on non-collision states of sawdust particles. However, in real life, collision of particles must occur. With several particles colliding after the cutting operation. This paper establishes a new perspective of the fractal properties of sawdust particles in motion as a motivation to understanding how to control its toxicitv of effects on sawmill workers and maintain sustainable sawmilling activities. In particular, the possibility of predicting the fractal dimension of the randomly moving sawdust particles in sawmills that is generated as fractal curves using the combination of probabilities and theoretical fractal dimensions is investigated for the first time. Cases were established on the possible representations of the theory and practice. As an example, four cases were designed around varied number of fractal pattern combinations drawn out of five and fifty different probabilities combinations, ten different random number generating seed values and maximum of four fractal curves generation iterations as driven parameters. Preliminary study of the differences between theoretical fractal box dimension recorded a maximum absolute percentage error of 7.24% for fractal curve associated with fractal pattern five (i.e. Koch 5). In all the cases studied, average absolute percentage error decreases between 3.52 ± 1.18 and 1.51 ± 1.14 while the correlation coefficient (R2) decreases between 0.9315 and 0.7365 from case 1 to case 4, respectively. It is concluded that the model is a good predictor of sawdust particle emission at colliding states from cutting operation. This is reflected in the fact that the higher the number of fractal patterns (generators) in a study case, the smaller the correlation coefficient between average estimated fractal box dimension and predicted fractal dimension of the sawdust particles in motion in the sawmill. "
The application of duffing's equation in predicting the emission characteristics of sawdust particles
(2010-09) Salau, T. A. O.; Oke, S. A.
"Sawdust particles soon after emission from the cutting machine usually move dynamically with transformation in some dimensions. This paper models the sawdust particle motion as a two dimensional transformation system of continuous time series. Cost could be saved using this approach instead of utilizing dynamic systems that depend on time history Two dimensional graphical representation of continuous time series of Duffing's dynamic system for sawdust particles was investigated with emphasis placed on application to sawdust particle motion and the saw machines. Pr~liminary studies were made using the harmonic functions, F(t) = Cos(wt) and F(t) = Sin(wt), for their familiarity in both science and technology communities. The solution to Duffing's model equation for the sawdust particles was sought from displacement and velocity perspectives, using the Runge-Kutta Algorithm. Linear transformation that guarantees non-negative values of time series was implemented. This was followed by the respective computation of the x- and y-components of the resulting time series values of the sawdust movement using a 21tmodulated time measured in radians. The graphical representations of the x- and y-components compared well quantitatively and qualitatively with the corresponding phase plots. The feasibility of modelling sawdust dynamics as emission from band saws was therefore demonstrated here, in approaches that thus advance knowledge of sawdust emission studies. "
Application of fuzzy logic concept to profitability quantification in plastic recycling
(2006) Oke, S. A.; Johnson, A. O.; Popoola, I. O.; Charles-Owaba, O. E.; Oyawale, F. A.
This paper aims at applying a fuzzy logic control model to profitability in a case study of the plastic recycling industry in Nigeria. The studies of profitability components of the plastic recycling industry as used to develop a model framework and the application of fuzzy logic control model to the framework are given in this paper. A brief introduction to profitability concepts as well as useful suggestions and conclusions are all integral part of this paper which is based on the application of a fuzzy logic model of control to profitability concept in plastic recycling industry.
Application of hybrid structural interaction matrix to quality management
(Inderscience Enterprise Limited, 2008) Oke, S. A.; Ayomoh, M. K. O.; Akanbi, O. G.; Oyawale, F. A.
This paper applies the concept of Hybrid Structural Interaction Matrix (HSIM) to the management of quality in a manufacturing organisation. The application is motivated by the need to evolve alternative prioritisation tools in quality management. A process, which could be used to analyse a specific situation, was presented by showing how Structural Interaction Matrix (SIM) and Hierarchical Tree Structure Diagram (HTSD) could be used to create a model. The result indicates the feasibility of applying the model in a specific situation in some useful insight into the problem solution. This research has serious implications for management in manufacturing organisation in that it saves tremendous energy and cost that could be expended on alternative prioririsation techniques due to minimization of time expended in seeking expert of opinion on the issue. This paper is new in that it shows a new dimension about thinking on quality management.
Application of neurofuzzy in the develoment of road bump designs
(2007-05) Oke, S. A.; Johnson, A. O,; Salau, T. A. O.; Adeyefa, A. O.
"This contribution is on the development of a neurofuzzy model that aids in capturing imprecision and uncertainty in the. various road bump parameters. Road bumps are structures built on roads to act as obstructions to vehicles plying these roads. The neurofuzzy methodology is used to check the vehicle speeds to acceptable standards. Particular use is made of neurofuzzy since it is an improvement on the traditional model proposed earlier in the literature. The work is motivated by the need for a more reliable and easily understandable methodology that guides decision makers in making correct decisions in a timely manner The results obtained demonstrate that it is feasible to apply the model in practice. The paper is new in that it proposes a novel approach to quantifying the results of road bump design in order to achieve worthy and reliable result. "
The combined application of quality function deployment and pareto analysis for hotel services improvement
(Inderscience Enterprise Limited, 2008) Oke, S. A.; Ofiabulu, C. E.; Banjo, A. A.; Akanbi, O. G.; Oyawale, F. A.
This paper discusses the combined application of Quality Function Deployment (QFD) and Pareto Analysis (PA) to hotel services. This paper improves the current quality management practices in a case study hotel. This results into increased customer patronage and improved hotel profit margin. PA is applied as a prioritisation tool for the purpose of financial investment decision. The study may be applicable to other hotels. It could also significantly affect the goodwill of the organisation as well as its profit margin. This paper is new, in that it appears to be the first application of Pareto cum QFD principles in hotel services, and a new way of prioritisation and quality improvement in hotels systems
Cost analysis in the implementation of ISO quality system in a petroleum refinery
(Inderscience Enterprise Limited, 2009) Oke, S. A.; Abudu, A. J.; Akanbi, O. G.; Oyawale, F. A.
The substantial amounts of financial and non-financial resources invested annually on petroleum refinery operations justify the need for documentation on the cost of implementing ISO quality systems ill refineries. The experience of ISO quality system implementation cost analysis in a petroleum refinery in a developing country is reported with a combination of mathematical model and application. The concept of strain as a function of growth in the physical sciences is adopted to conceptualise the growth phenomenon in the ISO organisation. Practically, developing a quantitative approach in evaluating cost of ISO implementation would help the manager in relying on scientific fact instead or intuition. The approach is new and has the potential for helping the top management in planning the strategy and allocating necessary funds for effective implementation of ISO quality systems.
Development and application of an inflation-based productivity model
(Akamai University, Hilo, Hawaii, 2007-11) Oke, S. A.; Oyedokun, I. O.; Akanbi, O. G.; Oyawale, F. A.
The paper presents a productivity model with an inflation component based on an established productivity measurement theory. The motivation for writing this paper is the need for conflict resolution at the implementation of productivity incentive programs. A common complaint from trade unions and organizations is that productivity is inaccurately assessed when the traditional input-output approach is utilized. The support for this argument is that a general rise in prices of materials utilized for production activities, without corresponding added values to the materials takes away the work group productivity efforts. This does not reveal the true measure of productivity. From the results obtained, there is a significant difference between the values obtained when the traditional productivity formula is used to compute the performance of a work group compared with the formula proposed in this work. This may be a strong point and a justification for the trade union argument. The limitation of the study is the difficulty that exists in monitoring the inflation values of the multiple products utilized as inputs into the production activities. For computational activities, a factor is chosen. The novelty of the model could be traced to the fact that it is the first time that such an approach and a systematic analysis would be made through the incorporation of the inflation factor into the productivity models.
Development of a performance measurement system for manufacturing systems
(Inderscience Enterprise Limited, 2008) Oke, S. A.; Oyedokun, I. O.; Akanbi, O. G.; Oyawale, F. A.
Taylor and Davis total productivity model has significant advantage over the traditional and more commonly used productivity models - its holistic nature. The model incorporates elements of net sales, inventory changes, wages and salary, investor's contribution, working and fixed capital. This paper presents a unique approach in the determination of the total factor productivity for a manufacturing organisation. This study is motivated by the dearth of models comprehensive enough to cover the major aspects of business apart from the usual input-output approach of productivity analysis which is limited to the output items and material/non-material resources. The results obtained clearly demonstrate the feasibility of applying Lagrange multiplier in optimising the variables and parameters of the model. The research has implications for decision making in several dimensions primarily it aids the utilisation of optimal solutions in arriving at decisions. This would avoid suboptimal decision making and promotes implementation of optimal decisions. This study is new, in that, it presents an enhanced version of a model that has been available to researchers several years back.
Estimation of thermal contact resistance in metal-plastic interface of semiconducting electronic devices
(2009) Oke, S. A.; Oyekunle, A. A.; Salau, T. A. O.; Adegbemile, A. A.; Lawal, K. O.
For decade, thermal contact resistance (TCR) has been measured experimentally. Unfortunately, the database, which should regularly support decision-making on TCR coefficients, seems not to exist. Thus, companies result to using outdated or irrelevant data that limits lifespan of electronics devices, their performance and reliability. This paper mathematically models the problem of TCR between two media (plastic-metal interface) in semi conductors with reference to resistance and the flow of heat across or interface of two surfaces that are in contact, particularly in engineering applications. In this paper, a semiconductor/ heat sink assembly is used to model the behaviour of thermal contact resistance. A cylindrical shaped semi-conductor was conceptualised, with the governing differential equations derived and the boundary conditions for the problem stated. The effect of parameters such as surface roughness, contact pressure, density of interstitial gas, heat capacity, thermal and mechanical properties on the temperature at the center of the semiconductor was studied. From the analysis, it can be inferred that by effectively lowering thermal contact resistance, efficient heat transfer results, which helps to prolong the life and reliability of the semi-conductor. The current work is motivated to fill an important gap that may be beneficial to practitioners in the semi-conductor industry.
A facility maintenance scheduling model incorporating opportunity and inflationary costs
(Inderscience Enterprises Limited, 2008) Charles-Owaba, O. E.; Oluleye, A. E.; Oyawale, F. A.; Oke, S. A.
This paper deals with facility maintenance scheduling model which incorporates opportunity and inflationary cost. A case study pertaining to a shipping firm has been defined as transportation model of minimizing Maintenance Cost (MC), Maintenance –Inflation Cost (MIC), Maintenance-Opportunity Cost (MOC) and combined Maintenance-Opportunity-Inflation Cost (MOIC), The optimal schedules indicating the ship maintenance, idle and operation periods were deduced for each approach. For all the samples, the costs of the first model were significantly (p≤0.05) different from that of the other three models. To reduce cost and delays, decisions for scheduling maintenance of a fleet of ships would be better informed if based on maintenance and opportunity cost indices in both inflationary and non-inflationary conditions.
Forced convection on isothermal plates and channels using diffusion velocity
(2010-06) Petinrin, M. O.; Dare, A. A.; Oke, S. A.
In many industrial applications, such as electronic systems, performance failure and breakdown usually occur due to poor thermal management, which could be adequately controlled through a proper understanding and management of the forced convection system and use of the vortex element method. The main contribution of this paper is that it shows how the vortex element method is capable of producing results similar to those reported in literature. The paper utilised vortex element method to model familiar problems in heat transfer, which is laminar flow over isothermal flat plate and isothermal two parallel-plate channels. Numerical models were developed using diffusion velocity method, a version of vortex element method, from vorticity transport equation and the energy equation for each of the cases. The velocity and temperature distributions, obtained for both plates and channels, were utilised to calculate Nusselt numbers with Reynolds numbers in the range of 20 to 120. The logarithmic plot of Nusselt number versus Reynolds number for forced convection on single horizontal plates yielded a slope of 0.46 and an intercept of -0.29 while that for forced convection in horizontal channels had a slope of 0.87 and an intercept of -0.88. The results obtained in this work show the diffusion velocity method to be a viable numerical tool for modelling fluid flow problems and also heat transfer problems.
Fractal dynamics of a bouncing ball on a accelerating lift tabletop with both constrained to vertical motion
(2008) Alabi, B.; Salau, T. A. O.; Oke, S. A.
"The bouncing ball problem has proved to be an important phenomenon in engineering applications involving vibro-transportation and vibratory feeder systems. In this paper, the dynamics of a bouncing ball falling consecutively on an accelerating lift tabletop is studied. Using simulation, it is established that the dynamic interaction of accelerating lift tabletop constrained to one-dimensional motion on which the ball is bouncing is fractal. The acceleration of the lift table top was varied gradually as a percentage of acceleration due to gravity over one thousand steps while the number of bounces-off made by the bouncing ball before the lift table top covered a fall distance of 10.000 m was recorded graphically. Similarly, every lift tabletop acceleration has the set of bounce-off height of the bouncing ball recorded graphically, and taken to be one third of height of fall. The number of bounce off drastically dropped to about zero when the acceleration of the lift tabletop was 40% of acceleration due to gravity. The graphical presentation of the ball bounce off height has normal distribution shape with fractal detail. This study showed that two objects, initially at different heights, falling under gravity, maintain separating heights for the period of their fall. The equation governing the dynamics of the bouncing ball and the lift tabletop are of quadratic type but the ball bounce off height graphical results contain fractal details. "
An inflation-based maintenance profitability model
(Inderscience Enterprise Limited, 2008) Oke, S. A.; Oyedokun, I. O.; Akanbi, O. G.; Oyawale, F. A.
The maintenance profitability problem is an important but emerging concept of maintenance performance measurement that views the maintenance function as a value adding subsection of the organisation. The service provided by the maintenance system to production is charged as a price, which results in the monetary contribution of the maintenance department to the organisation. In the same way, as production would add financial benefits to the organisation the maintenance system is portrayed as adding profit to the organisation. In this work, we present a mathematical model that calculates the maintenance profitability of an organisation under the condition of inflation using a composite mathematical function. It is concluded that viewing maintenance from a profit-making orientation provides a challenge to the maintenance team, thus driving them towards improved performance.
Mathematical modelling of lead assimilation by printing press operators in a poor indoor air quality environment
(Inderscience Enterprise Limited, 2008) Oke, S. A.; Ahmed, A. O.; Akanbi, O. G.; Oyawale, F. A.; Ofiabulu, C. E.
Most printing presses in developing countries are located in buildings with inadequate natural and mechanical ventilation such that the press operators work for major hours in poor indoor air quality buildings, which expose them to a wide range of health hazards such as lead poisoning. Understanding how poor air quality affects the operator's body system is studied using a methodology involving the principle of diffusion and the law of mass action. A hypothetical press in Nigeria is used as a case study to illustrate the workability of the model which may be of value to health inspectors to printing presses.
Mathematical modelling of the road bumps using laplace transform
(Centre of Professional Research Publications, 2007) Oke, S. A.; Salau||Adeyefa, O. G; Akanbi, O. G.; Oyawale, F. A.
The contribution of this paper to traffic engineering is the application of Laplace Transform to the quantification of speed control in the modelling of road bumps with hollow rectangular shape. The paper simulates the behaviour of a vehicle when passing over a series of bumps. In many countries the current practice used for lowering the vehicle speed is to raise road bumps above the road surface, if a hollow bump is used it may be economical and offers other advantages over road bumps raised above the road surfaces. The method models the vehicle as the classical one-degree-of-freedom system whose base follows the road profile, approximated by Laplace Transform. Then, a traditional vibration analysis is carried out and the isolation factor is calculated. A case study application is presented to substantiate the model developed. This case indicates how much difference the current model has compared to other existing models. Therefore, a relationship is established between the characteristics of the road profile, and the vehicle vibration response. Thus, the model's impact on the vehicle speed control is specified.
Mathematical modelling of the traffic congestion problem at a University campus
(2008-04) Oke, S. A.; Lofinmakin, O. O.; Salau, T. A. O.; Akanbi, O. G.; Ofiabulu, C. E.
"The traffic situation at many university campuses in developing countries has been a source of concern to both the school authority and the campus populace. This may be largely due to the increasing enrolment level for university admissions since most employers are certificate-biased instead of skill rewarding. The roads are often congested during the day thereby causing inconveniences to everyone. During the ""peak period"" when vehicular traffic is beyond what the road can contain conveniently, traffic jams occur, which accounts for a great amount of time wastage by commuters. This paper deals with the traffic congestion problem in a university in a developing country. The approach employs mathematical modeling to solve the problem. The principles of flow in fluid mechanics are interpreted at a macro level to the flow of traffic. The model describes the traffic situation, explains the causes and periods of congestion, and proffers a solution to the problem. "
Modelling of energy expenditure at welding workstations: effect of temperature on work performance
(Taylor and Francis, 2008) Oke, S. A.; Obioma, J. U.; Akanbi, O. G.; Adekunle, K.; Oyawale, F. A.
The welding workstation usually generates intense heat during operations, which may affect the welder's health if not properly controlled, and can also affect the performance of the welder at work. Consequently, effort to control the conditions of the welding workstation is essential, and is therefore pursued in this paper. This paper develops a mathematical model that maximises the work output while minimizing energy consumption at the welding workstation. Particular emphasis is placed on the effect of temperature on work performance. The important principle of conduction is applied through the human flesh that experiences temperature changes at the welding workstation. The welder-environment interaction is investigated with a focus on the welder's link and their relationship with blood flow. The results show that the blood in the arteries loses heat to the blood in the veins, and is aided by convection in the veins, Further heat losses occur in the skin layer of fat and muscle, and finally to the air. The study hopes to stimulate greater productivity and optimised resource utilisation. Thus, the Safety, Health and Environment (SHE) manager can assist in controlling the surroundings for optimal welder's comfort.
Occupational lead exposure in printing presses: an analytical approach
(Akamai University, 2008) Oke, S. A.; Phillips, T. E; Kolawole, A.; Ofiabulu, C. E.; Adeyeye, D. A.
Lead absorption poses a great threat to the health of workers in printing presses where commercial publishing is done. A case example is the commercial printing operations in Lagos, Nigeria. Since regular exposure to lead dusts could result in lead poisoning, complications that could cause death of victims, monitoring and controlling lead absorption of operators is essential for the maintenance of workers’ health and for the avoidance of the risk of incurring heavy losses due to litigation. The purpose of this paper is to model the process, rate, and quantity of lead absorption in operators of printing presses. Measurements of lead absorption are made and compared to standards in individuals for control purposes. Two approaches are used. The first shows the risk of being poisoned by lead. The second approach relates lead poisoning to the rates of intake of lead into the body and its elimination out of the body. This model viewed the absorption of lead as a cycle and applied the continuity equation to this cycle.