Department of Mechanical Engineering

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    Open Access
    Implementation of Road Maintenance Works in Nigeria, using Labour- based Methods and Technology’
    (1996-12-07) Falade, F.
    Roads form an integral part of our lives and provide means of safe and economic transport of goods and people for various purposes. Presently, majority of our roads both in rural areas and urban centre are in a deplorable state because simple functional defects on them are being left to degenerate to structural defects due to lack of timely maintenance. The existing maintenance procedure is equipment intensive. The aging machineries require spare parts, refurbishment or utter replacement but the deregulation of the economy and devaluation of Naira have made it almost impossible to acquire these items, therefore, road maintenance suffers a serious neglect. In this paper, the existing maintenance methods and their short-comings are examined. Alternative methods are presented for rehabilitation and maintenance of roads at local, state and federal levels to an acceptable performance level throughout the year. Labour - and equipment - based construction methods of infrastructure are compared using a pilot project: Rehabilitation and maintenance of an existing Noforija - Imokun Yewa Road at Epe, as a case study. Labour - based methods and technologies are recommended as versatile tools to achieve an efficient way of keeping the roads in good condition considering the high level of available local resources and reduction In maintenance cost.
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    Open Access
    Flow Field and Reynolds Stress Distribution of Low Turbulence Natural Convection in a Triangular Cavity
    (Begell House Incorporated, 2006) Talabi, S.O.; Olunloyo, V.O.S.; Kamiyo, O.M.; Collins, M.W.; Karayiannis, T.G.
    Triangular enclosures are typical configurations found in attic spaces of residential as well as industrial pitched-roof buildings. Previous studies on airflow within such spaces have focused on the laminar range. A numerical study has been carried out for time-dependent, two-dimensional low turbulence natural convection of air contained in the attic of a pitched roof of triangular cross-section. Two sets of boundary conditions have been considered: enclosure heated from the inclined walls and from the horizontal base wall, for aspect ratios (AR) of 0.33 ≤ AR ≤ 1.73 for Rayleigh number (Ra), 109 ≤ Ra ≤ 1011. In this paper, the flow field and Reynolds stress distribution are presented for the isothermal and isoflux cases.
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    Open Access
    Upper bound analysis for extrusion at various die land lengths
    (ScienceDirect (Elsevier), 2007) Ajiboye, JS; Adeyemi, MB
    The effects of die land lengths, a rarely investigated die extrusion parameter on the die-shaped profiles, on the extrusion pressures are investigated and presented. The analyses of the extrusion pressures by the upper bound method have been extended for the evaluations of the extrusion pressures to complex extruded sections such as square, rectangular, I,- and T-shaped sections with power of deformation due to ironing effect at the die land taken into account. The extrusion pressure contributions due to the die land evaluated theoretically for shaped sections considered are found to increase with die land lengths for any given percentage reduction and also increase with increasing percentage die reductions at any given die land length. The effect of die land lengths on the extrusion pressure increases with increasing complexity of die openings geometry with I-shaped section giving the highest extrusion pressure followed by T-shaped section,rectangular, circular-shaped die openings with square section die opening, giving the least extrusion pressure for any given die reduction at any given die land lengths.
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    Open Access
    A thermodynamic analysis of a biogas-fired integrated gasification steam injected gas turbine (BIG/STIG) plant
    (2007) Fagbenle, R. L; Oguaka, A.B.C.; Olakoyejo, O.T.
    A thermodynamic analysis considering both the first and the second laws of thermodynamics has been made on a 53 MW (net) biogas-fired integrated gasification steam injected gas turbine (BIG/STIG) plant. The energy utilization diagrams (EUDs) for the plant and for the reaction subsystems have also been considered, revealing both problems and potentials for improvement. The analysis indicates a thermal efficiency of about 41% (power based) and 45% (power and recovered heat based) but that the exergy loss in the combustion chamber is largest at about 79% of the total system exergy loss.
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    Open Access
    Effects of extrusion variables on temperature distribution in axisymmetric extrusion process
    (ScienceDirect (Elseiver, 2008-03) Ajiboye, J.S; Adeyemi, M.B
    A numerical method was developed to simulate the non-steady-state temperature distributions during forward extrusion process. The velocity, strain rates, and strain fields within the deformation zones during extrusion were obtained, using upper bound method of analysis to obtain internal heat generations coupled to the necessary heat transfer conduction equations. The computer program written in C++ language essentially simulates the extrusion process and takes into account extrusion variables such as material properties, friction conditions, extrusion velocity, extrusion ratio, die preheat temperature, billet height, percentage reduction in area, and die land length. The effects of billet height and percentage reduction in area on the temperature distributions within the dead metal zone give good agreements with experimental results. It is found that the higher the billet’s heights and higher the percentages reduction in areas, the higher the temperature rises during the extrusion process. The die land zone shows increasing temperature rise with increasing friction coefficient, while increasing friction coefficient has no effect on the dead zone temperature. Also, increasing speed of deformation shows an increasing dead zone temperature rise than a more gradual die land temperature rise. It can be stated that the extrusion temperature increases proportionally to the increase of the container temperature. r 2007 Elsevier Ltd. All rights reserved.
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    Open Access
    Biogas production from cassava waste
    (Trans Tech, Switzerland, 2008-04-15) Kehinde, J.A.; Ojolo, S.J.; Ebiobi, B.
    Anaerobic digestion is being taken seriously because of increasing concerns about the environmental hazards of wastes. The production of biogas, as an alternative source of energy was investigated in a designed and fabricated 200litre biogas reactor. The digester was operated on a batch-fed basis, and the feed stock was cassava waste which is readily available in Nigerian farms. The main aim was to explore other renewable sources as a means of less dependence on fossil fuels. A total of 1.94dm3/60kg waste of biogas was produced in 40 days of hydraulic retention time (HRT) with the average yield of 0.048dm3/day. The gas burned with a bluish colour indicating presence of methane (CH4). Temperature during the period of experiment varied between 27 and 330C. The pH of the slurry after the experiments averaged 3.21.
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    Open Access
    Design and development of a livestock feed pelleting machine
    (Faculty of Engineering, University of Lagos, Nigeria, 2009) Orisaleye, Joseph Ifeolu; Ojolo, Sunday J.; Fashina, A. B.
    Feeding pellets to livestock is advantageous to both the livestock and its farmer as it supplies the required nutrients to the livestock and is also economical. However, livestock feed pelleting equipment are known to be expensive and unaffordable particularly to the local farmer. A prototype of the pelleting machine was designed and developed for affordability. The machine was also tested to evaluate its performance. The machine consisted of a screw conveyor, die, barrel and hopper. It can be driven by an electric motor or a prime mover. The machine was tested with broiler’s mash and at different levels of moisture content using 500, 750 and 1000 cm^3 each of water and starch binder as preconditioners. The best pellets were formed using 750 cm^3 of either starch or water. The average specific energy consumption when 750 cm^3 of starch binder was used was 0.69 kWh/kg while it was 0.93 kWh/kg when water was used as preconditioner. The density of the pellets varied between 0.7 and 1 g/cm^3. This machine can be manufactured at a local machine shop for small-scale livestock farmers in developing countries.
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    Open Access
    Design and development of cashew nut shelling machine
    (Emerald Group Publishing Limited, 2010) Ojolo, Sunday J.; Damisa, O.; Orisaleye, Joseph Ifeolu; Ogbonnaya, C.
    Purpose The purpose of this paper is to investigate the physical and mechanical characteristics of the roasted cashew nut during fracture, by subjecting the nut to varying impact load tests at different orientations to ascertain the critical impact load that fractures the shell without damaging the kernel within. This load value was correlated with other parameters; shell/kernel moisture content level, average nut mass, to determine the required projection velocity to achieve this force. This projection velocity is the critical factor in sizing and design of the optimum configurations of the shelling impeller. Design/methodology/approach Mechanical properties of roasted cashew nut were first determined to know their fracture points. Each component of the shelling machine was designed. The components were assembled and the machine was tested for performance. Findings Machine throughput capacity was determined as 15.57 kg/h; shelling efficiency was 95 per cent; and whole kernel recovery was 70 per cent. Practical implications The efficiency in terms of whole kernel recovery could be improved by improving the pretreatment measures on the nuts. Originality/value The paper presents a machine which is affordable to peasant farmers and requires little or no training for operation and maintenance. The advantage of reduced unit cost can be derived from large‐scale commercial production of this sheller.
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    Open Access
    Design and development of cashew nut shelling machine
    (Emerald Group Publishing Limited, 2010-07-29) Ojolo, S.J.; Damisa, O.; Orisaleye, J.I.; Ogbonnaya, C.
    The purpose of this paper is to investigate the physical and mechanical characteristics of the roasted cashew nut during fracture, by subjecting the nut to varying impact load tests at different orientations to ascertain the critical impact load that fractures the shell without damaging the kernel within. This load value was correlated with other parameters; shell/kernel moisture content level, average nut mass, to determine the required projection velocity to achieve this force. This projection velocity is the critical factor in sizing and design of the optimum configurations of the shelling impeller. Mechanical properties of roasted cashew nut were first determined to know their fracture points. Each component of the shelling machine was designed. The components were assembled and the machine was tested for performance. Machine throughput capacity was determined as 15.57 kg/h; shelling efficiency was 95 per cent; and whole kernel recovery was 70 per cent. The efficiency in terms of whole kernel recovery could be improved by improving the pretreatment measures on the nuts. The paper presents a machine which is affordable to peasant farmers and requires little or no training for operation and maintenance. The advantage of reduced unit cost can be derived from large-scale commercial production of this sheller.
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    Open Access
    Development of a High Speed Abrasive Cutting Machine
    (Faculty of Engineering, University of Lagos, Nigeria, 2010-09) Ojolo, S. J.; Orisaleye, J. I.; Adelaja, A. O.
    A high speed abrasive cutting machine was designed and developed. The abrasive wheel of 4mm thickness was used and the speed was 2500 rpm. It is driven by an electric motor having a power of about 3.67 kW. Tests results on the machine showed that it can cut 25mm and 60mm mild steel rods in 7.5s and 21.3s respectively; 25mm and 60mm stainless steel rods in 15.3s and 136.7s respectively. It was discovered from the tests that depending on the length of cut and material being cut, the high speed abrasive cutting machine was more efficient, in terms of cutting time, than the power hacksaw. The grinding/wear ratio was also dependent on the material being cut and the length of cut.
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    Open Access
    BIOGAS TECHNOLOGY AS A NON-CONVENTIONAL SOURCE OF ELECTRICITY GENERATION
    (Federal Polytechnic Ilaro., 2010-11) Omoregbee, Henry
    Efforts by the government to solve the energy crisis in the country over the years with the conventional methods of generating electricity has not yielded the desired result hence the need for alternative source of energy. The paper examines the possibility of exploiting the readily available organic waste (biomass production) and the major benefits over the conventional methods of generating electricity. The impacts of adoption of this alternative source of energy on the environment, the sustainability and renewability of the system were highlighted.
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    Open Access
    MANAGING INTERNET ACCESS IN AN ACADEMIC ENVIRONMENT
    (Federal Polytechnic Ilaro., 2010-11) Omoregbee, Henry
    A growing awareness of the educational benefits of the Internet has contributed to a sense of urgency among tertiary institutions worldwide to deploy it. However, with its many advantages also come the numerous challenges and problems. Managing internet access by students is particularly problematic, as valuable and costly Internet connection time is often used by students to access pornographic sites, read newspapers, play games, and to engage in online chatting, while other students cannot find ample computer time to do their work. The problem of students submitting downloaded works from the internet as their projects and assignments is rampant, while scarce resources are wasted printing irrelevant documents and visiting sites with questionable educational values. This paper therefore looks at the benefits of the internet in an academic environment, and highlights the major problems and challenges of providing internet access to students. The paper also reviews management policies for improving the benefits students derive from using the internet.
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    Open Access
    Design and development of waste sorting machine
    (Scholarlink Research Institute, 2011) Ojolo, S. J.; Adelaja, A. O.; Orisaleye, J. I.; Kilankko, O.
    Nigeria is yet to develop a comprehensive scheme which is required to solve the current and persisting problem of waste management in the country. Whereas the crude methods of sorting wastes practiced may be efficient, it wastes useful time; hence the need for a mechanized sorting machine. An attempt has been made to develop a waste sorting machine, which is conceptualized to sort wastes into light materials, ferrous metals and other heavy materials. The machine is designed with the major components being the fan, the belt conveyor and the magnet. Tests carried out on the machine successfully classified wastes into light materials and heavy materials with inability to sort ferrous metals. Samples of wastes tested weighed 1.15kg and 3.53kg. The wastes consisted of an average of 32% of light materials and the time to sort the waste was 65 minutes per unit mass. This machine separates light materials such as paper, nylon, textile and heavy materials similar to nylon, ferrous and non ferrous metal, glass and paper sorted by the machine developed by Falayi et al. (2007) and the machine designed by Adzimah and Anthony (2009).
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    Open Access
    INVESTIGATING THE EFFECT OF ROAD CONDITION ON MAINTENANCE PROFILE OF TRICYCLE IN SOME LOCATIONS IN LAGOS METROPOLIS
    (Nigerian Society of Engineers (NSE) AGM meeting/Conference, 2011) Omoregbee, Henry
    This paper looks at the effect of road surface conditions on the maintenance profile of TRICYCLE mode of transportation in the suburb of Lagos Metropolis. Primary data such as purchase, maintenance and route/road histories were analysed for five selected locations covering three (3) local governments. Results obtained revealed that road surface conditions constitute a downtime and maintenance costs of the TRICYCLES as follows 9.6%, 69%, 13%, and 12% for U turn, Meiran, Agege, Abule-Egba respectively. Since transportation system worldwide thrive on efficiency, reliability, availability and functionality, it was concluded that road condition have great effect on these attributes. It therefore stands to good reason that good road conditions minimize frequent breakdowns and conversely maintenance cost. It was finally recommended that based on this research, extensive road rehabilitation works be carried out to increase the efficiency of mass transportation system in the suburb of the Lagos Metropolis.
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    Open Access
    Small hydropower (SHP) development in Nigeria: An assessment
    (Pergamon, 2011-05-01) Ohunakin, OS; Ojolo, SJ; Ajayi, OO
    This paper evaluates small hydropower (SHP) development and examines the current situation in Nigeria with respect to the established policies and Energy Power Sector Reform (EPSR) Act 2005. Hydropower sector witnessed about 360% growth between 1971 and 2005 and yet only about 5% of the vast small hydropower (SHP) potential is tapped by the few plants built between 1923 and 1964. Operating and maintenance costs are in favor of SHP development in the country, being the lowest when compared with the situation in European countries. The Nigerian Government has taken steps to diversify energy sources in order to promote renewable energy development by encouraging private investments in the energy sector through reforms, but this may not be adequate as there remain barriers against SHP development in the country. It is concluded that government must incorporate subsidies, feed-in-tariffs …
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    Open Access
    Quality Of Physical Facilities And Human Resources For Engineering Education In Africa.
    (2011-09) Falade, F.
    This paper assesses the quality of the facilities and resources for the training of engineers in some countries in Africa. The facilities are classified into internal and external. The internal facilities and resources are those within the training institutions while the external ones are those in the industry for use by the engineering students during the industrial attachment and after graduation for professional development training that is usually organized by professional body in each country. The internal facilities include classroom and laboratory spaces, teaching and research equipment, information communication technologies, library and periodicals while the external facilities includes office equipment and design software as well as projects to work on. In the training institutions and industry, highly skilled and experienced academics and practicing engineers are needed for proper transfer of skill to the prospective engineering graduates but to a large extent they are lacking. The basic infrastructure (energy and water) is in a poor state especially in the laboratories for the basic sciences as well as in the laboratories and workshops for engineering and technology; the situation is similar in the industry.Each country sets minimum standards (human and non-human resources) comparable to International Standards for engineering education but in general the minimum standards are hardly met quantitatively and qualitatively in most African Universities. The inadequacies in teaching, laboratory and workshop facilities as well as manpower for capacity building contribute to the diminution of the quality of engineering graduates in Africa. In order to improve the quality of facilities, the skills and abilities of the engineering personnel in the training institutions and industry, there is need for adequate funding. Partnership between universities and industry needs to be strengthened with the universities providing the platform for the creation of knowledge and the development of human resources while the industry provides platform for the commercialization of the research outputs.
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    Open Access
    Investigation into the effects of solid lubricant on the surface characteristics of some metals during orthogonal machining
    (Emerald Group Publishing Limited, 2011-12-31) Ojolo, S.J.; Damisa, O.; Iyekolo, O.
    The main purpose of this paper is to explore the use of solid lubricant during orthogonal machining of carbon steels. This is a pioneer work in Nigeria. Most works have been on oblique cutting using conventional oil as lubricants. Different steels (low, medium and high carbon) were machined at different cutting conditions and tool geometries to determine the effects on surface characteristics while applying solid lubricant. The results showed considerable improvement in the surface finish with the use of solid lubricant. There was also a decrease in surface roughness values as compared to wet machining. Further works on solid lubricant’s effects on cutting force and residual stress could be done. From the findings of this work, solid lubricant use can be advocated as a better alternative to conventional cutting fluid. It is easily recoverable from the chips after machining. So far, in Nigeria, solid lubricant has not been exploited as coolant during machining. This paper will be a platform for other researches on solid lubricants as coolant during cutting/machining in Nigeria.
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    Open Access
    ALTERNATE ENERGY SOURCES FOR CI ENGINES: A FOCUS ON NIGERIA
    (Energy Technology & Management Conference ETMCon, University of Ibadan., 2012) Omoregbee, Henry
    The supply of energy through sources that have been adjudged not to be amenable to cleanliness and supportive of emission control, which are also finite, necessitates the search for alternative sources of energy. This becomes particularly important for transportation, specifically Internal Combustion Engines. It is also applicable to developing countries like Nigeria, which have the desire to develop technologically and would benefit from alternative technological paths to ensure the development, deployment and utilization of environmentally friendly technological products. Nigeria, a country rich in oil resources, would benefit from proper study and development of alternative products, specifically Compressed Natural Gas, which she has in abundance. CNG has shown a variety of capacities and adaptability, which makes it suitable to address endemic problems such as emissions, energy efficiency and thrift of conventional fuels like Gasoline and Diesel. It then becomes imperative that the pace of development and deployment of CNG consuming engines be fast-tracked. In this research, we hope to facilitate this process by comparing alternative power units, CNG units with conventional gasoline units. And also we hope that by employing the design principles and other factors that have made gasoline vehicles dominant in the passenger vehicle market, we shall arrive at an efficient and reliable CNG powered solution for passenger vehicles.
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    Open Access
    Experimental Study on the Effect of Deforming Material and Speed on Friction and Lubrication by Tip Test
    (Transactions of the ASME, 2012) Ajiboye, JS
    Choosing the proper metal forming lubricant for nonferrous metals such as aluminum, copper, and brass has become a difficult and complicated decision. The effects of deformation velocity and the influence of deforming material were determined in the two sets of experiments carried out using a single punch with a roughness magnitude Ra of 0.17 lm and four lubricants such as grease, corn oil, VG100, and VG32. In the first set, two different deformation speeds of 0.1 and 1mm/s were used for cylindrical specimens made of aluminum alloys of 6061-O, 1050-O, and copper alloys tests using a counterpunch die of roughness magnitude Ra of 0.08 lm. In the second set of experiments, cylindrical specimens made of aluminum alloys of AA2024-O and AA6061-O and three deformation speeds of 0.1, 1, and 5mm/s were used to evaluate the performance of each lubricant under increasing ram speed, but with a roughness magnitude Ra of 0.63 lm. All the lubricants show reduction in maximum load with increasing deformation speed except grease which shows a rise in the maximum load from zero to a maximum at a deformation speed of 1mm/s and then descends gradually to a minimum load at a speed of 5mm/s for AA2024-O and AA6061-O. This load reduction seen with grease as lubricant is probably due to thermal softening; therefore grease will not be considered a desirable lubricant under increasing deformation speed because of the adverse effects on the tooling. The present findings show that tip test can be utilized to select an appropriate lubricant for a particular alloy. It reveals that none of the tested lubricants can be used for copper alloy as all the lubricants show increasing measured load for increasing speed magnitude. However, of the liquid lubricants (corn oil, VG100, and VG32) considered, corn oil shows as the best lubricant for cold forging operations of aluminium 6061-O, 1050-O, and 2024-0 under increasing speed magnitude. Also, the tip test has been able to differentiate among materials.
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    Open Access
    SOLAR ENERGY, A PANACEA TO RURAL ELECTRIFICATION UTILISATION: A CASE STUDY OF NIGERIA
    (Energy Technology & Management Conference ETMCon, University of Ibadan., 2012) Omoregbee, Henry
    Solar energy has always been one of the abundant renewable energies in Nigeria, and today there is a gap between its availability and utilization. This is underlined by the fact that the average sunshine hour per day is 6hrs and the reserve estimate is 3.5- 7.0KWh/m2-day. At present in Nigeria, electricity installed capacity sourced from coal, oil, water, gas and fossil nuclear materials is about 3500MW compared with projected electricity demand of 15,730MW by 2015. The continued usage of coal, oil, water, gas and fossil nuclear is faced with a lot of challenges ranging from the release of greenhouse gases, un-replenished and restricted installation among others. This paper examines solar energy utilization in Nigeria, vis-à-vis rural energy consumption and makes recommendations on how to fully harness solar energy to augment electricity generation into the national grid for increased power supply to rural communities.