FACULTY OF TECHNOLOGY

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Nigeria Gazette
(The Government Printer, Nigeria, 1953-01) Federal Government of Nigeria
Electron beam decomposition of CdCl2
(American Institute of Physics., 1984) Green, M.; Aidinis, C. J.; Fakolujo, O. A.
The e-beam stimulated reaction, CdCl2 (s)----Cd(s) + 2Cl(g), has been studied in cadmium chloride thin films between 303 and 483K using 2-keV electrons. The dose required to make 90-mm-deep holes at 483K is 3 X10-3 Ccm-2. Extrapolated dosing levels of ~6X10-5 C cm-2 are expected. The use of CdCl2 as a positive-type electron resist in a new scheme is proposed. A working model, useful for considering the e-beam stimilated decomposition energetics and mechanism, is briefly discussed.
Effect of some variables on the carburization of a locally produced steel
(Nigerian Metallurgical Society, 1987) Adepoju, O. T; Balogun, S. A.; Adeyeye, A. D.
The effects of carburizing time, temperature and percentage energizer on the case-depth and hardness of a steel ST37-2 have been studied. For carburizing medium consisting of hardwood charcoal and coke and various amount of sodium carbonate as energizer, increasing carburizing time and temperature increased both the depth and hardness of the case. Increasing both the amount of energizer and carburizing time lowered the activation energy for the carburization process. The average hardness of the carburized layer decreased with tempering. Two processes are found to be operative during carburizing; one which is strongly activation energy dependent and the other which is mildly dependent on activation energy.
Photovoltaic characteristics of thin films of Cu2SnS3
(Elsevier, 1987) Kuku, T. A.; Fakolujo, O. A.
We report for the first time the optical absorbtion and photovoltaic characteristics of thin films of Cu2SnS3.Films obtained by the direct evaporation of the synthesized compound were observed to be deficient in copper, while those grown in an atmosphere of copper vapour were observed to be more stoichiometric. Both sets of films are characterised by indirect and direct absorption edge propoerties. The indirect absorption edges are at 1.065 and 1.510 eV, while the direct band edges are at 1.658 and 1.770 eV for the copper deficient and stoichiometric films respectively. The stoichiometric film is characteried by p-type semiconducting properties while a Schottky type solar cell developed from it is observed to have potential photovoltaic characteristics
Cadmium chloride thin films: hydration-dehydration
(Elsevier Sequoia, 1987) Green, M.; Fakolujo, O. A.
E-beam induced decomposition of inorganic solids
(Martinus Nijhoff Publishers, 1988) Green, M.||||; Aidinis, C.; Fakolujo, O.
A general model for the e-beam induced decomposition of covalent and ionin inorganic solids is outlined. The primary electron beam produces enegetic electron/hole pairs; these decay to the band edges, and either recombine or participate in the chemical decomposition of the solid. The kinetics and mechanism of several system is discussed, including CdCl2 and PbI2. The importance of temparature in decomposition is remarked and it is suggested that induced decomposition is remarked and it is suggested that induced decomposition mostly starts at 0.6 melting point (K). The usefulness of various inorganic systems, as resists, for x-ray masks, for local indiffusion sources and for metal inter-connects is noted.
Effects of temper annealing temperatures and times on the mechanical properties of cold-worked aluminium 1200
(1989-04) Aderibigbe, D. A.; Sowole, O.O.
Experiments have been conducted to develop temper- annealing schedule for continusly cast and cold-worked aluminium 1200. By using the method of graphical combination of the results of tensile and deep- drawn test, it is shown that a cost-effective temper-annealing schedule that would impart improved mechanical properties( compared with full annealing at 460° C for 6 hours) can be developed for Al-1200. For optimum combination of desired properties during deep- drawing, the 75% cold-worked material should be temper-annealed at 380 °C for 3 hours; the 85% cold-worked material should be temper-annealed at 400 C for 2 hours while the 90% cold-worked Al-1200 should be temper-annealed at 460 °C for 3 hours
A correlation for predicting the viscosity of Nigerian crude oils
(Society of Petroleum Engineers, 1990) Amoo, O. A.; Isehunwa, S. O.
An empirical equation that could be used for predicting the viscosity of Nigerian crudes is presented in this paper. The correlation uses oil specific gravity as the main correlating parameter, and also incorporates the effects of reservoir pressure, temperature and oil formation volume factor. Data from well over 400 samples of Nigerian crudes were used for developing the correlation, with most samples however, from reservoirs at or above saturation pressure. The results show however that the correlation could have general applicability. The correlation when compared with some earlier works proved to be more accurate for Nigerian crudes. Graphical and Statistical error analyses undertaken suggest good performance and accuracy. The correlation should prove valid for estimating the viscosity of Nigerian crudes, as well as other crude types having properties that fall within the range of the data used in this work.
STUDIES ON THE EFFECT OF POSTHARVEST FACTORS ON PLANTAIN QUALITY
(1992-03) ADELUSOLA, M. A.
This study was undertaken to evaluate the social and technical factors affecting plantain handling in Nigeria, with a view to recommending measures of minimising losses and improving product quality. Questionnaires on the effect of production, transportation and marketing practices on postharvest losses were administered to farmers, transporters and traders respectively in a survey of three plantain producing States and one non-producing State in Nigeria. Based on the findings of this survey, physical characteristics of plantain which are likely to change as the plantain matures were investigated using two cultivars of plantain namely, Agbagba, a false horn type and Obino l'ewani, a French type, harvested between 8 to 14 weeks after anthesis, to obtain indicators for determining harvest maturity. Also, a methodology for measuring qualitative and quantitative losses in plantain was development. In addition, the effect of maturity at harvest, packaging and the Vibration experienced during transportation on mechanical damage were investigated in simulated transit studies, as well as selected quality attributes of processes products from the Agbagba plantain harvested between 8 to 12 weeks after anthesis, in Order to establish Optimum handling conditions for plantain for the distribution and Processing outlets. The measurement of finger weight and finger length have been developed as new objective and non-destructive methods for harvest maturity determination in plantain cultivars. It was also observed that the measurement of bruise area on the peel and percentage weight loss were associated with aesthetic quality, whilst the measurement of trimming losses on the pulp was a good indication of quantitative losses and the number of days to full ripening was an indication of the storage life of the two cultivars. Harvesting at the immature stage increased the susceptibility of the plantains to underpeel bruising leading to significantly (p = 0.05) higher trimming losses and weight losses in the two cultivars. Lining the packaging Containers with polyethylene reduce the damage significantly. The sensory quality of flavour and texture were affected by the stage of maturity at the time of harvest. Chips and ’dodo' prepared from immature plantain scored significantly (p = 0.05) lower points than mature ones. Even though it might be adviceable to harvest plantain at an immature stage in Order to extend its green-life, this work clearly shows that this would be at the expence of quality.
A type curve approach to qualitative description of reservoir fluids
(Society of Petroleum Engineers, 1993) Isehunwa, O. S.; Falade, G. K.
Qualitative description of reservoir fluids is normally based on such parameters as saturation pressure, gas in solution, viscosity and density. Most Engineers ignore compositional data unless when phase behavior predictions or compositional simulation are to be undertaken. This work describes a simple, quick method of qualitative reservoir crude assessment, using the well known Type Curve matching techniques with fluid compositional data. The method is demonstrated for some Niger Delta reservoir crudes, and shown to be useful in checking the validity of laboratory PVT results in cases where there are disagreements between the experimental and observed (field) values of saturation pressure. Volatile crudes and condensates can also he readily identified. It. would appear that the method can be applied regionally, as well as locally (in-field) as an aid in reservoir-to-reservoir fluid correlation. It can also help to ide1ltify non-equilibrium fluid distribution in. large, thick, or segmented reservoirs.
Classification and evaluation of crop storage structures in Western Nigeria
(The Nigerian Society of Engineers, 1993-12) Mijinyawa, Y.
A survey involving the use of questionnaires and personal communication during field trips was carried out in Western Nigeria with the aim of classifying and assessing the efficiency of the existing structures for the storage of crops. Barns; cribs; trenches; platforms; warehouses and silos are among the important Storage structures. The existing structures could be efficient with proper management but a major limitation of most of them is the low unit capacity which is inadequate to cope with the present volume of agricultural production. Research efforts should concentrate more on improving the existing structures rather than their replacement.
Post-graduate professional experience in electronic and electrical engineering
(1994) Kamil, I. A.
A brief but illustrative account of the author's acquired experience in the areas of consultancy, teaching and research, and repair and maintenance is presented
A two-parameter correlation for predicting oil recovery factor in water-drive reservoirs
(Society of Petroleum Engineers, 1994) Isehunwa, S. O.; |Nwankwo, S. U.
A simple correlation has been developed for estimating primary recovery factors for Niger Delta oil reservoirs. The correlation which was developed, from data collected across the Niger Delta, is valid for reservoirs with strong water drives. Only two major parameters are required for the recovery factor calculations in this work, unlike other multi-parameter correlations. This makes this correlation very easy to apply. An expression has also been included for predicting residual oil saturation, where core or log analysis data are not available. The results obtained using these models have been compared with other published models, and applied to many case studies, with better predictions. Graphical and statistical error analyses also confirm good correlations. These correlations should also, yield good predictions for reservoirs from other regions that have similar reservoir and fluid characteristics.
Analysis of mud filtration properties using factorial design
(Society of Petroleum Engineers, 1995) Isehunwa, S. O.; Orji, H. I.
Determining the filtration properties of a mud system requires that experiments be run for both the standard API and the high Temperature High Pressure (HTHP) tests at intervals throughout the duration of drilling an oil well. However, cost and hazard considerations cause more emphasis to be placed on the standard API test at ambient conditions, without taking into account the effects of elevated downhole pressures and temperatures on filtration properties. In this work, the factorial design concept was applied to the filtration properties of drilling muds. Different samples of water based bentonitic muds were used for the experimental runs at both Low Temperature - Low pressure (LTLP) and high Temperature - High Pressure (HTHP) conditions. The input variables considered were temperature, pressure, solids content, mud weight and time; while the response variables were fluid loss and cake thickness. The final results are presented in the form of a statistically significant model that enables prediction of filtration properties at both LTLP and HTHP conditions. This method minimizes the inherent risks usually associated with operating filter presses at elevated pressures and temperatures. In addition, it saves time and cost by minimizing the number of experimental runs always required to assess mud quality and maximizes the information obtained from the few experimental runs. This experimental design technique can also be applied to the quality assessment and control of other drilling fluid properties.
The design, construction and testing of a wooden silo for grain storage
(The Nigerian Society of Engineers, 1996-03) Lucas, E. B.; Mijinyawa, Y.
A hexagonal, double-walled, wooden silo of sides 1.2m, height 1.8m and of 7m3 capacity was designed. The walls and floor were taken as stressed skin panels. These were fabricated using Mansonia altissima for the ribs, while exterior grade structural plywood was used as sheathing. The silo was subjected to nondestructive testing in accordance with the British Standard Code of Practice CP: 112 and joints separation, consolidation movement of the foundation and floor deflection were periodically measured over a period of two weeks during which the structure was under load. At the end of the test period there was no measurable consolidation movement and the joints remained intact while the floor deflection was within permissible limit of ∆ ≤ L/180. Further testing and evaluation including subjecting the silo to loading for longer duration and taking measurements of stresses induced on the silo components are to be undertaken.
Problems and prospects of metal silos for grain storage in Western Nigeria
(The Nigerian Society of Engineers, 1997-06) Mijinyawa, Y.
A survey involving the use of structured questionnaires and personal communication was carried out in Western Nigeria to ascertain the type and extent of use of silos for the storage of grains. Steel and Aluminium were found to be the predominant materials used for the construction of the silos. They are mainly used to store shelled corn and in a few instances, rice, cowpea and soybean. The prohibitive cost of silo acquisition limits their ownership and use to the Ministries of Agriculture, Co-operative Societies, agro-based industries, Teaching and Research Institutes and a few large scale private farms. Silos are not used by the small to medium scale farms. The withdrawal of the Ministries of Agriculture from direct grain production and the collapse of co-operative grain storage programmes have resulted in the abandonment of many silos. The metal silos experience the problem of moisture condensation on the roofs and walls which leads to the deterioration of stored grains through moulding, caking and rapid multiplication of insects. Losses of as much as 10% of total storage through these sources have been recorded for some silos. Adequate funding of current research efforts to develop local materials for grain silo construction is recommended.
The use of local building materials for the construction of farm structures in western Nigeria
(The Nigerian Society of Engineers, 1997-09) Mijinyawa, Y.; Dahunsi, D.
A Survey of the pattern of usage of building materials in the small - to - medium farms in Western Nigeria was undertaken. Wood was the commonest construction material in use, followed by earth products and natural fibers. Decay and weathering of natural fibers including timber; arid the erosion of earth products were the major problems experienced with their uses. Treatment of the natural products before use was found wanting. Adequate seasoning and preservative treatment of natural fibers’ and earth stabilization are recommended for durability. Cost is a vital consideration in the choice of construction materials for farm structures. The choice of local materials goes some way to reduce cost. Numerous improvements on performances of some local materials have been devised in the Research Institutes. There is a need for effective extension linkage between the research institutions and the farmers.
Comparative studies of temperature fluctuations within wooden and steel silos in Ibadan
(The Nigerian Society of Engineers, 1997-12) Lucas, E. B.; Mijinyawa, Y.
Temperature fluctuations and moisture condensation within the interiors of a steel and wooden silos were determined experimentally. The steel silo is of 1mm thickness while the wooden silo is a two-layered wall panel of 12mm and 6mm thick plywood separated by 50mm air-gap. Measurements taken during the hotter months of March and April in Ibadan showed that temperature fluctuations in the steel and wooden silos were 9°C and 7°C respectively. Corresponding maximum temperature in the silos were 38.5°C and 37.2°C. While the interior of the wooden silo remained dry, the steel silo had condensed moisture droplets lining its inner walls. Since moisture condensation in a silo contributes to grain spoilage by biological agents, wooden silos are rated superior in respect of reducing this adverse feature.
A survey of livestock structures in south western Nigeria
(Research Communications, 1998) Mijinyawa, Y.
A survey involving the use of structured questionnaires and personal communication was undertaken in South Western Nigeria to identify the livestock in the area, and their housing methods. Chicken, pigs, rabbits, goats, sheep and cattle were the major animals found while the housing structures include baskets, battery cages, deep litter houses, cages, hutches, pens, sheds and yards. In about half of the sites surveyed animals kept were not provided with housing, while in the other places where they were provided the structures were poorly equipped and overstretched to cope with the population of animals kept. Wood products are the predominant materials of construction accounting for as much as 50 to 70% of the total volume of materials used in the construction of some of these structures. Others are natural fibers, concrete, wire mesh and corrugated roofing sheets. Poor waste management, decay in wood members, and pitting and cracking of concrete were some of the flaws identified. Integrated designs to reduce the burden of waste collection and increase its effective utilization, use of durable timber species and preservative treatment to further improve the length of service, and the use of good quality concrete constituents and mixture are recommended.
The development and evaluation of a flat-type wooden incubator
(School of Agriculture and Agricultural Technology (SAAT), Federal University of Technology, Akure, 1998) Ewemoje, T. A.; Olorunnisola, A. O.
"A flat-type, 60-egg capacity incubator was designed, constructed and tested. The incubator differs from existing designs in that the cabinet was made from a 3-ply, 4mm thick interior grade plywood to reduce cost and at the same time enhance heat insulation. Also, two domestic kerosene lanterns were provided to supplement heat generation by three 40 W electric bulbs during electricity outages as commonly experienced in Nigeria.When tested with 30 eggs of a commonly sold chicken breed, incubated at average temperature of 38° C and relatively humidity of 58%, the chicks were hatched within 20 days. Relatively high percentages of fertility and hatchability of 86.2% and 76% respectively, as well as a relatively low chick mortality rate of 18.5% were recorded. "