Mechanical Engineering-Conference Papers
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- ItemOpen AccessImplementation 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.
- ItemOpen AccessFlow 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.
- ItemOpen AccessBiogas 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.
- ItemOpen AccessBIOGAS TECHNOLOGY AS A NON-CONVENTIONAL SOURCE OF ELECTRICITY GENERATION(Federal Polytechnic Ilaro., 2010-11) Omoregbee, HenryEfforts 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.
- ItemOpen AccessMANAGING INTERNET ACCESS IN AN ACADEMIC ENVIRONMENT(Federal Polytechnic Ilaro., 2010-11) Omoregbee, HenryA 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.
- ItemOpen AccessINVESTIGATING 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, HenryThis 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.
- ItemOpen AccessQuality 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.
- ItemOpen AccessALTERNATE ENERGY SOURCES FOR CI ENGINES: A FOCUS ON NIGERIA(Energy Technology & Management Conference ETMCon, University of Ibadan., 2012) Omoregbee, HenryThe 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.
- ItemOpen AccessSOLAR ENERGY, A PANACEA TO RURAL ELECTRIFICATION UTILISATION: A CASE STUDY OF NIGERIA(Energy Technology & Management Conference ETMCon, University of Ibadan., 2012) Omoregbee, HenrySolar 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.
- ItemOpen AccessTemperature variation on the heated base of a solid substrate cooled with different type of heat sinks(HEFAT, 2014-07) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThree-dimensional numerical studies were carried out to investigate forced convection heat transfer and fluid flow in a solid substrate cooled using different types of micro heat sinks. The objective of this study is to investigate which heat sink type gives the lowest temperature variation on the heated base of the solid substrate which is being cooled. A low temperature variation indicates a low temperature gradient which, in practical application, improves the reliability of the electronic device. The different heat sinks considered are single microchannels, two-layer microchannels with parallel and counter-flow of fluid, single microchannels inserted with circularshaped micro pin fins and two-layer microchannels inserted with circular-shaped pin fins. All the heat sinks are geometrically optimised using a computational fluid dynamics code with a goal driven optimisation algorithm subject to global constraints. The thermal performance of the heat sinks considered in this study is based on two objectives namely, the minimisation of the peak temperature which results in maximisation of the thermal conductance and the lowest temperature variation on the heated base. The heat sink with the largest value of thermal conductance and lowest temperature variation on the heated base for the range of pressure drop considered is chosen as the best heat sink design. Numerical results of thermal performance for fixed axial length of the solid showed that cooling the solid substrate with the two-layer microchannel with counter-flow of fluid gave the lowest temperature difference at base of the solid substrate and also performed best in maximising thermal conductance at pressure drops of 20 and 30kPa.
- ItemOpen AccessGeometric optimisation of multi-layered microchannel heat sink with different flow arrangements(Begel House Inc., 2014-08) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis paper presents the use of the constructal design technique to optimise the geometry of a multilayered microchannel heat sink. The objective of this numerical investigation was to minimise the peak temperature of the solid substrate into which the microchannel was embedded. Parallel and counter-flow of fluid through the microchannel is considered in this study. The geometric optimisation of the microchannel was carried out using a computational fluid dynamic (CFD) code with a goal-driven optimisation workbench tool subject to global constraints. Optimal dimensions of the multi-layered microchannel in terms of the channel hydraulic diameter, channel aspect ratio, solid volume fraction, for the fixed solid volume that minimised the peak temperature and maximised the thermal conductance were reported. Results showed that as the pressure drop increased, the minimised peak temperature decreased and the maximum thermal conductance increased. When the number of layers of the microchannel was increased from two to three, the results of the thermal conductance became worse. For the design parameters used in this study, the two-layered stack microchannel with counter-flow arrangement was the best design in minimising the peak temperature and maximising the thermal conductance when the pressure drop was between 20 and 60kPa.
- ItemOpen AccessComparison between the thermal performance of single and two-layer microchannels inserted with micro pin fins(Begel House Inc., 2014-08) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis paper presents a three-dimensional numerical study of steady, laminar, incompressible flow and forced convection heat transfer through a two-layer rectangular microchannel heat sink inserted with pin fins. The objective of the study was to optimise the geometric configuration of the combined two layer microchannel heat sink with micro pin fin inserts for a fixed solid volume so that the peak temperature within the configuration is minimised. The geometric optimisation of the microchannel was carried out using a computational fluid dynamic code with a goal driven optimization workbench tool subject to global constraints. Effects of pressure drop on the minimised peak temperature and maximum thermal conductance for the fixed solid volume were reported. The thermal performance of the single and two-layer microchannel heat sink inserted with micro pin fins based on the minimised peak temperature and maximised global thermal conductance were compared and their results were reported. For a constant solid volume of 0.9mm3 and fixed length of 10mm, it was observed that while the performance of the single microchannel was improved with the micro pin fins, it was not the case with the two-layer microchannel. These results showed that inserting pin fins in a two-layer microchannel does not enhance the heat transfer when the length of the solid substrate is fixed. The thermal performance of the combined design when the axial length of the solid substrate was relaxed was also reported.
- ItemOpen AccessNumerical investigation into two-layered microchannel with varying axial length and temperature-dependent fluid properties(American Society of Mechanical Engineers, 2015-11) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis study numerically investigates the thermal performance of a two-layered microchannel heat sink with varying axial length, varying solid substrate aspect ratio (ratio of height to width of the silicon solid substrate) but with a fixed total volume constraint and water as the working fluid. The optimal geometry in terms of channel hydraulic diameter, channel aspect ratio and the solid substrate aspect ratio was selected based on the minimised peak temperature on the heated base of the solid substrate with a constant heat load of 100W. The optimal aspect ratio AR of the solid substrate was discovered to be 4 for all pressure drop range considered in this study but the optimal axial length shows a dependence on pressure drop. Results of the effect of varying axial length on surface heat flux, minimised thermal resistance and temperature variation on the heated base of the solid substrate were also presented and discussed.
- ItemOpen AccessNumerical optimization of forced convection of wall thickness of heated plates cooled using alumina-water nanofluid(Begel House Inc., 2018-08) Aduralere, T.T; Olakoyejo, O.T; Adewumi, O.O; Adelaja, A.O; Obayopo, S.O; Meyer, J.PThis paper applied constructal theory and design to present the numerical optimisation of forced convection of a rectangular plate placed between a heat source and a cooling fluid (Al2O3-Water) driven by forced convection at the upper surface. The main objective was to numerically optimise the configuration of the wall thickness using computational fluid dynamics (CFD) in such a way that the peak temperature was minimised from the solid to the fluid. An optimisation algorithm called Response Surface Optimisation within CFD code was applied in order to search for the optimal wall thickness configuration which improved thermal performance by minimising thermal resistance for a wide range of Reynolds numbers. The effect of varied Reynolds number and constant heat flux on the optimal geometry was reported. There was a unique optimal design geometry for a given value of Reynolds number. Results obtained show that an increase in the applied Reynolds number and the volume fraction of the cooling fluid leads to a decrease in minimum peak temperature.
- ItemOpen AccessEvaluation of some Non-Edible Vegetable Oils as Lubricants for Conventional and Non-Conventional Metal Forming Processes(ESAFORM, 2019) Idegwu, CU; Olaleye, SA; Agboola, JB; Ajiboye, JSThe current study focuses on evaluation of the suitability of some non-edible vegetable-based oils as lubricants for conventional metal forming operations in general and non-conventional processes such as severe plastic deformation in particular. Four non-edible oils were chemically extracted using a Soxhlet extractor and hexane solvent from mango seeds, water-melon seeds, African cherry seeds and avocado peer seeds. Comparison was made between performance of these environmentally benign oils and a mineral based SAE 40 Oleum super monograde oil in the equal channel angular extrusion (ECAE) of a cylindrical AA 6063 aluminum rod through a channel angle φ of 90o and outer angle ψ of 20o at different extrusion speed. The results show that mango oil has the best load reduction for all extrusion speeds tested, better than SAE 40, followed by avocado oil, then watermelon oil with cherry oil given the least performance. It was found, regardless of any of these oils tested, that as extrusion speed increases, there is a reduction in the load and hardness of the material tested. Comparing the unECAEed specimens with the ECAEed specimens, hardness decreases in all the ECAEed specimens tested. Further, from the hardness measurement, it was found that specimens ECAEed with vegetable-based oils probably produced better grain homogeneity than specimens ECAEed with SAE40, which perhaps account for their slightly higher hardness values. Also, although the viscosity of the SAE 40 is better than mango and avocado oils, these vegetable based oils performed excellently well when used as lubricants during equal channel angular extrusion of AA 6063 aluminum and show promising potential as alternative to mineral oil, SAE 40.