Doctor of Philosophy (Ph.D.) Theses and Dissertations

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    Analysis of batch arrivals with multiple service for unbalanced queueing systems
    (Department of Mathematics, Faculty of Science ,Obafemi Awolowo University ,Ile -Ife, 0222) Babalola, Ajiboye Reginald
    This study designed a prototype of an unbalanced Combined Input Crosspoint Queued (CICQ) queueing system, obtained the possible states at the moment just before a departure for some specific gridpoints and provided the system solution in terms of those grid points and analysed the performanceof the proposed system. These were with a view to establishing relevant flow balance equations and analysing the traffic at various levels of interactions of contending units for congestion, complexity and grid points. Considered is a two-stream toll gate system modified from the CICQ switch system of homogeneous and heterogeneous packets. The Markov Modulated Poisson Process (MMPP) were superimposed at the input port to obtain the defined states at (u, v,w)k for epoch or moments just after a departure of type k which identified admissible states and their transition probability matrix was obtained using various combinatorial reasonings. The work thereafter, formulated governing equations from relevant flow balance equations, which were of the form ΠP = Π and solved them for stationary probability vectors. Subsequently, the work obtained the mean recurrence times for each state and mean first passage times from one state to the other. Highlighted in particular, were the situations of the extreme cases of heavy traffic (HT) with 27 possible states when the system was saturated with contending units and two cases of restricted light traffic. The restricted traffic was such that traffic (u, v,w) at the moment just before a departure, was guided by the conditions u ≤ 2n, v ≤ 2n, w ≤ n and v+w ≤ 2n where u, v,w and n were integers connoting number of different units in the queues. The light traffic case I (LTS I) connoted n = 1 with 17 admissible states and the light traffic case II (LTS II) connoted n = 2 with 86 admissible states for a 27 grid point system. For a combination of service times τ1, τ2, τ3, the resulting combination were evaluated for cohersion, stability and efficiency using measures of the minimum mean first passage times Tmin(ijk), Concentration Index (C) and the Euclidean Distance Measure (dI/II ). The result from the mean first passage time for all three systems provided a measure of the sensitivity for the stationary probability vectors as defined in their respective underlying states. The mean first passage times tijk was found to be a stochastic process of its own with respect to each of the models, matrices and values, in correspondence to the gridpoints as defined by the parameters of the light traffic case I (LTSI), light traffic case II (LTSII) and the heavy traffic situations (HTS). Thetendency to concentrate (or dominate) on any state is lower for the heavy traffic, though steady, but cannot be sustained when compared with the light traffic cases. This tendency for concentration was found to be closer for both light traffic cases but the LTS II case was uniformly less concentrated than that of the LTS I case. The order, therefore, of the concentration Index C for the three systems is HTS < LTS II < LTS I by considering all the grid points. The value of the concentration index C for the heavy traffic ranges from 0.047 to 0.05, that of the LTS II ranges from 0.07 to 0.35 while the one for LTS I ranges from 0.08 to 0.37. The minimum Euclidean distance (dI/II ) compared to the restrictive light traffic cases, in relation to matching similar states, is wide. The width is in the multiple of 104. The least active destination states service type III has the lowest value of 4.34, while the most active destination state for service type III has a value of 6.42. It was noted that the minimum Euclidean distance dI/II appeared progressive as the destination states increases. However, the order of spryness for the three types of service is service type I > service type II > service type III. The study concluded that the Combined Input Crosspoint Queued switch model is able to predict relative performances of traffic systems based on the objective matrix for different levels of complexity and congestion.
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    Chemical studies on the deterioration of palm oil
    (Department of Chemistry, Obafemi Awolowo University., 1983) OKIY, Dere Arubore
    The work reported in this thesis is on the chemical changes which take place when palm oil is subjected to thermal deterioration and the effect on the nutritional value of leaf protein. The state of deteriorated palm oil on the nutritional value of leaf protein as determined by PER, BV, NPU and TD were examined; this was not worse than diets without the oil samples.
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    Studies on the productivity of echinochloa stagnina (RETZ.) P. beauv. in the kanji lake basin of Nothern Nigeria.
    (Department of Botany, Obafemi Awolowo University, Ile-Ife, Nigeria., 1985) Emmanuel, Asuquo Obot.
    Echinochloa stagnina growing in Lake Kainji is identified, described, and separated from Echinochloa pyramidalis and Echinochloa colona. The grass has been recognised by cattle farmers as an important source of dry-season fodder for their stock, while the power generation authorities view it as a problem to the Lake's hydrology and optima power generation due to its contributions to water loss from the lake through evapotranspiration.
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    Studies on the extracellular enzymes of staphylococcus aureus strians isolated from patients in Ile-Ife.
    (Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria., 1987) Adebola, Ajao Hunt.
    The possible contribution of certain groups of enzymes to pathogenicity of staphyloccus aureus has already been suggested (Jawet et al., 1980; Berman et al,.) The ability of stains of S. aureus to synthesize such enzymes were therefore investigated.
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    Intergrated Explorations and Statistical Studies of Geochemical Data of Amphibolites in Ife-Ilesa Gold Field
    (Department of Geology, Faculty of Science, Obafemi Awolowo University., 1988) Ajayi, Taiwo Rufus
    In the Ife-Ilesa schist belt, occurrence of alluvial gold is spatially related to the amphibolite complex which consists of mafic/ultramafic rocks and pelitic schists. The amphibolites constitute the most widespread mafic potential source rocks. An integrated exploration and statistical studies of geochemical data in this area was carried out to investigate the geochemical characteristics of the amphibolites, recognise and effectively delineate anomalous geochemical patterns related to potential areas of Au mineralization and evaluate geochemical and geological relationships.
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    A mathematical model for explosions with chain branching and chain breaking kinetics
    (Department of Mathematical Obafemi Awolowo University, 1989) Samuel Segun OKOYA
    A mathematical model for explosions with chain branching and chain breaking kinetics is presented in this thesis to give further insight into the theory of combustion reactions under physically reasonable assumptions.
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    Phase transitions in some metal 10-hydroxy and 9, 10-dihydroxyotadecanoates.
    (Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria., 1992) Prince, Chukwulozie Mbaneme.
    This work reports the conductance of some metal carboxylate systems and the enthalpy/entropy of phase transition of the systems. The objective was to study the physical properties of new compounds (10-hydroxyotadecanoates and 9, 10-dihydroxyotadecanoates of lead, zinc, cadmium and mercury) with a view to examiing their usefulness as materials with potential technology applications.
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    Physiological Ecology of diatoms in some freshwaters around Ile-Ife.
    (Department of Botany, Falcuty of Science, Obafemi Awolowo University., 1993) OKUSAMI, Victoria Bamidele
    An ecological study on diatoms was carried out on six water bodies both inside and outside the Obafemi Awolowo campus, Ile-Ife, (O.A.U) with a view to relating their occurrence and diversity with prevalent environmental conditions. There water bodies include Opa reservoir on O.A.U. campus, two permanent ponds on O.A.U. Teaching and Research Farm. Oduduwa College Fish pond in Ife town and two streams on Tonkere road near the University gate
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    The Biology of the fish genus clarias in Opa reservoir, Obafemi Awolowo University
    (Department of Zoology, Faculty of Science, Obafemi Awolowo University., 1995) ABAYOMI, Olatokunbo Solomon
    A study on the identification , distribution, food and feeding habits, pattern of reproduction, and fecundity , age and growth and types of parasites affecting the fish genus clarias was carried out in Opa reservoir between 1989 and 1992.
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    Structural changes in vegetal cover in Ife and Ede regions of Southwestern Nigeria between 1963 and 1993
    (Department of Geography, Faculty of sciences, Obafemi Awolowo University, 1995) Ayobami T. SALAMI
    This research on spatial and temporal analysis of vegetation with remotely sensed data in a part of Southwestern Nigeria. Emphasis was placed on the identification of structural changes of the vegetation although, some baseline data on the floristic characterization of the area were also generated from the study.
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    Inventorization and modelling of the emission of greenhouse pollutants in Nigeria
    (Department of Physics, Obafemi Awolowo University, Ile-Ife, Nigeria., 1995) Imoh, Bassey Obioh.
    The determination of the emission rates pathways for the emission of greenhouse gasses and other toxic air pollutants is carried out with a view to determining the sources and source strengths. This will enable the prognosis of emission pathways for the emission relevant processes as well as the modelling of the various impacts on the atmospheric environment in Nigeria.
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    Some aspects of the population dynamics of sarotherodon galilaeus (artedi) in the opa reservoir of Obafemi Awolowo University, Ile-Ife, Nigeria.
    (Department of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria., 1996) Fawole, Olatunde Olubanjo.
    Field and laboratory investigations were carried out some aspects of the population dynamics of sarontherodon galilaeus in Opa reservoir between January 1989 and march 1994. These aspects include the mode of distribution, food and feeding habits reproduction, age and growth as well as the level of parasitic infestation of the fish species. The fishing employed were gill netting cast netting of the fish species.
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    Capability development in adopting active technology transfer strategy in Nigeria Industries.
    (Department of Technology Management, Falculty of Technology, Obafemi Awolowo University., 1998) Ephraim Chukwuma OKEJIRI
    The main technology acquisition strategy of most developing countries including Nigerian is based on the concept of technology transfer which emphasizes importation of production technology. This development strategy which emerged post second world war era had roots in the revolutionary theory of social change.
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    The effect of vegetation physiognomy on sediment yield in Ile- Ife area of southwestern Nigeria
    (Department of Botany, Obafemi Awolowo University., 1999) Samson Olajide OKE
    A study was carried out to discern the magnitude of runoff and sediment yield under various vegetation physiognomy with a view to establishing the relationship between runoff /sediment yield and various vegetation parameters in Ile- Ife area of Southwestern Nigeria .
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    Moss, surface runoff and associated sediments as indicators of metal and trace organic pollution in Lagos, Ile Ife and Osogbo areas
    (Department of Chemistry Obafemi Awolowo University, 2000) OGUNFOWOKAN Aderemi Okunola
    The levels of sediments and mosses (PAHs) and trace elemental composition of runoff and associated sediments and road side moss samples, Barbula lambarenesis (p.vard) were determined by Gas-liquid chromatography- mass spectrometry (GC_MS), Atomic absorption (AAS) and capillary Electrophoresis n(CE) techniques. The aims of the study were to develop a simple and efficient procedure for the GC_MS measurement and identification of PAHs in surface runoffs, sediments and mosses of Lagos, Ile-Ife and Osogbo areas determine areas
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    The mode of action of ichthyotoxic principles in raphia hookeri fruit.
    (Department of Biochemistry, Obafemi Awolowo University, Ile-Ife, Nigeria., 2004) Obuotor, Efere Martins.
    The main objective of this study was to isolate and purify, through guided lethality assays, the major ichyotoxic principles contained in the fruit mesocarp of Raphia hookeri, Mann et Wendland. Arecaceate. The study also sought to elucidate the structures of the purified principles and propose a possible mechanism for their action, with a view to rationalizing the traditional use of the fruit mesocarp for fishing.
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    Studies on the identification and distribution of simulium damnosum cytospecies of human onchocerciasis in South Easter Nigeria.
    (Department of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria., 2004) Ibeh, Olusola Olubunmi.
    Morphological and cytogenetic studies have been carried out on the members of the simulium damnosium complex in Southeast Nigeria. The studies were undertaken for a period of 12 months to ascertain the sessional variation and changes in the species compositionm simulium samples collected from different bioecological zones.
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    An evaluation of the Nigerian innovation system and technoloical capability building in the manufacturing sector.
    (Department of Technology Management Obafemi Awolowo University, 2005) OKE, Joseph Sunday
    This study evaluated the knowledge generation and utilization performance and the operational environment of the Nigerian innovation system with the aim of establishing the level of technological capability building in the manufacturing sector. In conclusion, the Nigerian innovation system was generally too weak to support sufficient technological capability building in the manufacturing sector due to factors such as low spending on R&D, low level of S&T human resources , poor state of research facilities and poor linkage between academic /research institution and firms.
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    Development and performance testing of an electrochemical treatment process for selected industrial wastewaters
    (Department of Civil Engineering, Falculty of Technology Obafemi Awolowo University, 2006) Isalah Adesola OKE
    The study investigated the treatment of selected industrial wastewaters electrochemically with a view to developing a system that would remove pollutants from wastewaters effectively without losing much of the electrodes. The study concluded that the electronical treatment method was effective and could be used along side with conventional treatment processes.
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    Physico-Chemical and trace element characteristics of vegetation, soil and water in Bituminous sands deposit area of Ondo state, Southwestern Nigeria.
    (Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife., 2007) Adedbiyi, Festus Mayowa
    Vegetation, soil and water (ground and Surface water) in bituminous sands deposit area of Ondo state, Southwestern Nigeria were analyzed for the physic-chemical characteristics and trace element contents with a view to providing baseline data for these parameters in the various ecological components and a framework for establishing of relationships between the chemistry of mineral deposits and the soil, water and vegetation in the study.