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- ItemOpen Access28-Day Strength Predicting Model for Foamed Aerated Concrete Containing Pulverized Bone as a Partial Replacement of Cement(International Association of Scientific Innovation and Research (IASIR), USA, 2013-09) Ikponmwosa, E; Falade, F; Fapohunda, CThis paper presents the results of a mathematical model developed for predicting the 28-day compressive strength of foamed aerated concrete containing pulverised bone as partial replacement of cement for the purpose of quality controls. Strength-porosity relation was used as a basis for the development of the model, and the Bisection Methods of Numerical analysis was used to evaluate the inherent constants. For all the percentages of cement replacement with pulverised bone, the experimental strength values compare well with those of the model. It can thus be concluded that the model is valid for foamed aerated concrete with and without pulverized bone. The model has been validated up to 20% replacement of cement with pulverised bone.
- ItemOpen AccessA Simulation and Experimental Investigation of the Thermal Characteristics of Refractory Bricks Produced Using Fireclay and Agroforestry Wastes(Journal of Casting & Materials Engineering, 2022-05-28) Obidiegwu, E. O.; Esezobor, D. E.; Mgbemere, H. E.; Odili, C. C.Manufacturing and processing industries usually consume large quantities of materials and energy in the course of their opera tions. The energy supplied for high-temperature processes are used partially for the actual technical process and between 30 to 40% of the energy escapes through the walls of the reactor into the atmosphere, leading to a high degree of thermal inefficiency and fuel consumption. This paper studies the thermal behaviour of insulating refractory bricks produced from a blend of fireclay and agroforestry wastes. The fireclays used were obtained from Ukpor deposit in Anambra State (Latitude 5.95°N, Longitude 6.92°E), Osiele deposit in Abeokuta, Ogun State (Latitude 7.18°N, Longitude 3.45°E) and Kankara Katsina State (Latitude 11.93°N, Longitude 7.41°E), all of which are in Nigeria. Samples were prepared with various weight percentages (60–100 wt.%) clays and (0–40 wt.%) of agroforestry waste, with grain sizes between 212 and 600 µm. Raw materials and the developed refractory bricks were characterised using appropriate standard techniques. The chemical, mineralogical constituents and phases present in the microstructure were examined. Physical and thermo-mechanical properties were investigated. The insulating refractory bricks developed have porosity of 78.83% , cold crushing strength (CCS) 3.144 kN/m2 and thermal conductivity 0.04–0.046 W/(m∙K) that compare favourably with imported bricks 75–85%, 2.756 kN/m2 and 0.049 W/(m∙K) in both physical, mechanical and thermal properties respectively. The reason is that the agroforestry waste used (coconut shell), served to create the pores that improve insulation after burning. Also the ash that remains serves as reinforcement to improve the mechanical properties. The thermal behaviour of the bricks was studied using Finite Element Method and shows a strong correlation with the experimental findings. This indicates that the produced insulating bricks have the thermal properties required for insulation of furnaces.
- ItemOpen AccessAcetylation, crystalline and morphological properties of structural polysaccharide from shrimp exoskeleton(Engineering Science and Technology, an International Journal, 2017) Gbenebor, O.P.; Adeosun, S.O.; Lawal, G.I.; Olaleye, S.A.The extraction of a structural polysaccharide, a-chitin, from shrimp exoskeleton via chemical means using hydrochloric acid (HCl) and sodium hydroxide (NaOH) has been done. Concentrations of 0.4, 0.8 and 1.2 M for both HCl and NaOH were chosen to evaluate the acetylation degree (DA), crystalline structure and morphology of the chitin. The N-acetyl groups’ content in the structural polysaccharide ranged between 65.6 and 99.4% in decreasing order of both acid and alkali concentrations combination used. The magnitude of chitin average hydrogen bond energy EH was majorly influenced by OH(6). . .OC intra and CO. . .HN intermolecular hydrogen bonds as they showed more predominance than OH(3). . .O(5) and OH. . .OC intra and intermolecular hydrogen bonds. Chitin diffraction planes, crystalline index (Crl) and crystallite size (Dhkl) were investigated by X-ray diffraction (XRD) with reflections observed on (021), (110), (130) and (013) planes. The Crl occurred between 79.4 and 87.4%, while crystallite sizes were between 0.544 and 3.64 Å for the samples. Morphological study using scanning electron microscopy with energy dispersive spectroscopy SEM/EDS showed strong calcium and oxygen peaks. This established the shrimp shell surface to be composed of calcite and trace elements such as nitrogen and silicon. The observed a-chitin rough surfaces were attributed to the low degree deacetylation recorded during alkali treatment.
- ItemOpen AccessAcoustic Pressure Waves in Vibrating 3-D Laminated Beam-Plate Enclosures(Advances in Acoustics and Vibration in Hindawi Publishing Corporation, 2009) Osheku, C.A.; Olunloyo, V.O.; Damisa, O.; Akano, T.T.The effect of structural vibration on the propagation of acoustic pressure waves through a cantilevered 3-D laminated beam-plate enclosure is investigated analytically. For this problem, a set of well-posed partial differential equations governing the vibroacoustic wave interaction phenomenon are formulated and matched for the various vibrating boundary surfaces. By employing integral transforms, a closed form analytical expression is computed suitable for vibroacoustic modeling, design analysis, and general aerospace defensive applications. The closed-form expression takes the form of a kernel of polynomials for acoustic pressure waves showing the influence of linear interface pressure variation across the axes of vibrating boundary surfaces. Simulated results demonstrate how the mode shapes and the associated natural frequencies can be easily computed. It is shown in this paper that acoustic pressure waves propagation are dynamically stable through laminated enclosures with progressive decrement in interfacial pressure distribution under the influence of high excitation frequencies irrespective of whether the induced flow is subsonic, sonic, supersonic, or hypersonic. Hence, in practice, dynamic stability of hypersonic aircrafts or jet airplanes can be further enhanced by replacing their noise transmission systems with laminated enclosures.
- ItemOpen AccessAfrican Regional Conference on Engineering Education:(2004) Falade, F.The African Regional Conference on Engineering Education (ARCEE) provides a forum for all the stakeholders in engineering and technology education within the region to come together and deliberate on common problems within the compass of engineering and technology and proffering solutions to them. We have had two meetings in Lagos, Nigeria (2002 and 2004). During ARCEE 2002, it was decided that the programme be held biennially and to be rotated among the member nations while in 2004 an action plan was drawn up and strategies were mapped out for its implementation. The details of the action plan are presented in this paper. The third meeting tagged 'ARCEE 2006' is to be held in Pretoria, South Africa.
- ItemOpen AccessAirflow and Heat Transfer Analysis within Flat-top Roofs Heated from Below(The University of the West Indies St. Augustine , Trinidad, 2021) Kamiyo, O.Natural convection in attic of non-conventional rooftops has received considerable attention in recent years due to its importance in thermal management of modern pitched- roof buildings. In this study, a finite -volume numerical investigation of laminar fluid dynamics and heat transfer of air within the attic of a flat- top roof structure has been predicted for bottom isothermal heating at varying pitch angle. The heat transfer between the walls results in multiple thermal plumes and multi-cellular flow structure with the number, size and strength of the counter -rotating cells reducing with increasing pitch angle. The results further show that the peculiar shape of the roof has significant effect on the fluid flow and heat transfer. Particularly, the truncated triangular architecture of the roof prevents the formation of large, dominating and upper-row cells at the midsection of the attic. At low pitch, the intensity of the vortices results in thorough mixing of air and, hence, uniform temperature distribution within the attic. The averaged Nusselt number for the hot ceiling wall which depicts the rate of convective heat transfer into the attic is in negative - gradient quasilinear relationship with the roof pitch. The practical significance of the predicted results is that, due to the peculiarity of the flat-top roof structure, heat loss to the attic is minimized when the roof pitch is relatively high; particularly not less than 300 and made as low as possible if the attic is to be used for drying of food crops
- ItemOpen AccessAn Algorithm for Least Squares Computation Using the Manifold and Hilbert Space Dialectics(Theoretical Mathematics & Applications, International Scientific Press, 2012-03-12) OLALEYE, J.B.; ABIODUN, O.E.; OLUSINA, J.O.The method of least squares is widely used in numerical analysis of data in all applied quantitative fields. Although there is only one least squares criterion, several schemes have been used for its implementation. The manifold approach treats the entire least squares process, including the representation of the variables, the model formation and the computations, in terms of manifolds. A manifold is a group of variables or functions taken together and treated as an entity in the computation process. This paper presents the least squares optimization on the manifolds and shows that the express formation and solution of the usually formidable normal equations can be avoided by employing the Hilbert space axioms and methods in the Euclidean space generated by the axial manifolds. The sequential and systematic approach of the new scheme, the preservation of the group structure and the analytical insights it provides for understanding the fundamental geometry of the least squares problem, all of which are demonstrated in the sample applications presented, support the conclusions that the manifold approach is less daunting, requires less core storage space and facilitate better understanding of the problem and the solution.
- 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 AccessAmeliorating Traffic Congestion and Impact on Climate Change with Park and Ride Transport(Covenant University, 2017) Rikho, J.; Ndambuki, J.; Kupolati, W.; Adeboje, A.; Kambole, C.Traffic congestion occur as more vehicles ply the road and result in reduced travel speed, increased travel time, unnecessary queuing, obstruction on travel path and impediment to traffic flow. Thirteen per cent of greenhouse gases (GHG) emitted are caused by the transportation system which continues to grow. Fume emanating from vehicles contributes greatly to the emission of GHG. Park and Ride was investigated within the Central Business District (CBD) of Tshwane with a view to improving the traffic congestion and reducing the effects of GHG on the climate. Traffic counts and questionnaires distribution were done on the major access routes to the CBD. The quantities of carbon dioxide (CO2) emitted by traffic and that would be reduced when park and ride system is implemented in the City of Tshwane Metropolitan Municipality (CTMM) were determined. Results of traffic volume counts showed high dependence of more than 70% of people on passenger cars as the mode of transit within the study area. It also revealed that almost 89% of the interviewed population are delayed by traffic, on their way to the work place in the morning. Fifty-four per cent of the people interviewed showed readiness to utilize the park and ride facility if their safety and security would be guaranteed. Furthermore the study showed that 96.2% of CO2 emitted could be reduced by the implementation of the park and ride system on the A Re Yeng BRT and also in the major cities of Tshwane.
- ItemOpen AccessAnalysing wear behaviour of Al–CaCO3 composites using ANN and Sugeno-type fuzzy inference systems(Neural Computing and Applications, 2020) Sosimi, A.A.; Gbenebor, O.P.; Oyerinde, O.; Bakare, O.O.; Adeosun, S.O.; Olaleye, S.A.Design of experiment for the development of stir cast calcium carbonate-reinforced aluminium composite is a search for optimum combination of material and process control parameters for best physical and mechanical properties. A softcomputing model can accurately learn the complex interactions between process parameters to provide great insights in the development of this composite. This paper demonstrates and analyses the potential of artificial neural network (ANN) and Sugeno-type fuzzy inference systems (FIS) for wear behaviour prediction of calcium carbonate-reinforced aluminium composites. The models were trained with data collected from the experiment. The data consist of filler particle size of 150 lm with weights fractions varied from 0 to 25 wt%, in step of 5. Wear test data at different time of contacts (30, 60, 90, 120 and 150 s) and variable loads of 2.27 N, 4.54 N and 6.80 N were collected, resulting to 120 length vectors. Comparing the experimental results of wear test with those predicted using the ANN and Sugeno-type FIS, the integration of calcium carbonate particulate enhanced the wear characteristics of Al matrix up to 200%. On the use of backpropagation neural network with 4–3–1 architecture for wear prediction, the Levenberg–Marquardt training algorithm performs better. For Sugeno-type FIS, the Gaussian membership function resulted to the best prediction of wear rate. When ANN and Sugeno-type FIS performance on the test set were analysed based on some statistical parameters, the later returned an R2 value of 0.9775 as against ANN’s value of 0.3684. The predicted wear rate using ANFIS with Gaussian membership functions was in good agreement with the experimental values.
- ItemOpen AccessAnalysis of convective-radiative porous fin With temperature-dependent internal heat Generation and magnetic field using Homotopy Perturbation(Journal of Computational and Applied Mechanics, 2017) Sobamowo, M.G; Adeleye, O.A; Yinusa, AIn this work, thermal behavior of convective-radiative porous fin with temperature-dependent internal heat generation subjected to magnetic field using homotopy perturbation method is analyzed. The developed symbolic heat transfer model is used to investigate the effects of convective, radiative, magnetic parameters on the thermal performance of the porous fin. From the study, it is established that increase in porosity, convective, radiative and magnetic parameters increase the rate of heat transfer from the fin and consequently, improve the efficiency of the fin. The homotopy perturbation method used in the work is validated with the results of a numerical method. The results of the two methods are in excellent agreement. Therefore, this study provides a platform for comparison of results of any other method of analysis of the problem. Also, such an analytical tool is valuable as a design and optimization approach for finned heat exchangers where each fin/row is analytically analyzed and where the surrounding fluid is influenced by a magnetic field.
- ItemOpen AccessAnalysis of dissimilar weldeing of austenitic stainless steel to low carbon steel by TIG welding process(International Journal of Metallurgical & Materials Science and Engineering (IJMMSE), 2015-10) Osoba, L.O.; Ekpe, I.C.; Elemuren, R.A.In the current study, the effect of heat treatment on the dissimilar metal welding of austenitic stainless steel (AISI 304L) and low carbon ferritic steel (AISI 1005) using Tungsten Inert Gas (TIG) welding process was investigated with a view to minimize and/ or eliminate the previously reported danger of inhomogeneous hardness distribution experienced across the fusion zone. Heat treatment (Normalizing) of the as welded dissimilar metal was carried out in a muffle furnace at temperatures ranging from 7500C to 8500C and held for varied length of time. Micro structural evaluation and mechanical properties of the fusion zone (FZ), heat affected zone (HAZ) and the base metals (BM) were performed using microscopy and micro hardness evaluation. The result shows that for dissimilar metal weldment, the non-uniform hardness distribution in the fusion zone can be essentially eliminated by using appropriate post weld heat treatment.
- ItemOpen AccessAnalysis of Dissimilar Welding of Austenitic Stainless Steel to Low Carbon Steel by TIG Welding Process(International Journal of Metallurgical & Materials Science and Engineering (IJMMSE), 2015) Osoba, L.O.; Ekpe, I.C.; Elemuren, R.A.In the current study, the effect of heat treatment on the dissimilar metal welding of austenitic stainless steel (AISI 304L) and low carbon ferritic steel (AISI 1005) using Tungsten Inert Gas (TIG) welding process was investigated with a view to minimize and/ or eliminate the previously reported danger of inhomogeneous hardness distribution experienced across the fusion zone. Heat treatment (Normalizing) of the as welded dissimilar metal was carried out in a muffle furnace at temperatures ranging from 7500C to 8500C and held for varied length of time. Micro structural evaluation and mechanical properties of the fusion zone (FZ), heat affected zone (HAZ) and the base metals (BM) were performed using microscopy and micro hardness evaluation. The result shows that for dissimilar metal weldment, the non-uniform hardness distribution in the fusion zone can be essentially eliminated by using appropriate post weld heat treatment
- ItemOpen AccessAnalysis of Flow Induced Acoustic Waves in a Vibrating Offshore Pipeline(2010-12) Osheku, C.A.; Olunloyo, V.O.; Akano, T.T.Flow induced acoustic wave characteristics in a vibrating subsea pipeline is investigated. For this problem, acoustic wave equations are formulated and matched for the various vibrating segments. The pipeline system is idealized as a network of fluid conveyance elastic beams resting on a moving seabed via recent advances in subsea pipeline vibrations. By employing operational methods, closed forms results as influenced by internal fluid variables and subsea soil geotechnical properties, are computed for design applications. It is further shown that the vibration of any pipeline system is modulated by transverse, longitudinal and vibro-acoustic natural frequencies.
- ItemOpen AccessAnalysis of pollution status of River Illo, Ota, Nigeria.(Springer, 2008) Longe, E.O.; Omole, D.O.An assessment of the pollution status of River Illo, located within River Owo catchments area in Ota, Ogun State, Nigeria, was carried out. The River’s response to de-oxygenation due to BOD loading from an abattoir and its dissolved oxygen (DO) level was predicted using the modified Streeter-Phelps model. The average concentrations of measured parameters at the sampling stations include: 2.24 mg/l of DO, 312.85 mg/l of BOD, 782.86 mg/l of chemical oxygen demand, and 620.76 g/l of total solids. The DO model for River Illo showed a positive correlation between measured and calculated DO, while the dissolved oxygen curve gave a double spoon shape of two major segments with distinct zones of degradation, decomposition, and recovery. The self-purification factor (f) for both segments ranged between 0.8 and 1.1 depicting River Illo as a slow moving or sluggish river. The above results revealed slow re-aeration of the water body while full recovery from pollution was difficult. The treatment of River Illo before usage is very essential to ensure public health safety of users from waterborne diseases.
- ItemOpen AccessAnalysis of the thermal performance of single and multi-layered microchannels with fixed volume constraint(Proceedings of the Romanian Academy, 2018) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis study presents a numerical analysis of forced convection heat transfer and steady, laminar, incompressible fluid flow through single-, two- and three-layered microchannels with different flow arrangements and fixed total volume constraint. Previous studies on multi-layered microchannel heat sinks have shown that these types of heat sinks perform better than single-layered microchannel in terms of reducing thermal resistance and pressure drop, but this is obtained with increased total volume of the solid substrate because equal volumes of the single-layered microchannel are stacked to obtain the number of desired layers. In this paper, the total volume of the solid substrate for all the microchannels considered was fixed at 0.9 mm3 and the geometries of the different microchannels were optimised based on the objective of maximising the thermal conductance using a computational fluid dynamics package with a goal-driven optimisation tool. The results show that for a fixed total volume and fixed inlet fluid velocity, the pumping power of the two-layered microchannel with the different flow arrangements was 10% less than that required for the single-layered microchannel but was increased by about 12% when the number of layers was increased to three. The results obtained from this study show that the multi-layered microchannels give very good results without increasing the total volume of the solid substrate as presented in previous investigations.
- ItemOpen AccessANALYSIS OF THE TRANSIENT STABILITY LIMIT OF NIGERIA’S 330kV TRANSMISSION SUB-NETWORK(Faculty of Engineering, University of Nigeria, Nsukka, 2017-01) Oluseyi, P.O.; Adelaja, T.S.; Akinbulire, T.O.The poor investment in the network expansion programme has led to high level of grid fragility experienced in the power transmission system in Nigeria. Thus, any little disturbance often results in cascaded outage which is very hazardous to the power system equipment and operation. In order to overcome or ameliorate the influence of this challenge, the network engineers have to devise methodologies based on the dynamic stability analysis. This motivates the development of power system transient stability model presented herein. The developed model is thus applied to a specimen of the Nigeria’s transmission power system, i.e. the Ikeja-West Sub-network. This choice is influenced by the fact that the Ikeja-West sub-network is the hub of power transmission arteries in Nigeria. Thus the Electrical Transient and Analysis Program (ETAP) software is deployed to operate on the ensuing model. This then leads to generating a series of results that demonstrates the different scenarios in respect of the system stability studies. The method adopted is quite appealing and promising as a tool in sustaining system stability and security during slight disturbance to the network during operation.
- ItemOpen AccessAnisotropic responses of mechanical and thermal processed cast Al-Si-Mg-Cu Alloy(The Minerals, Metals & Materials Society, 2015) Adeosun, S.O.; Akpan, E.I.; Balogun, S.A.; Onoyemi, O.K.The effects of ambient directional rolling and heat treatments on ultimate tensile strength (UTS), hardness (HD), percent elongation (PE), and impact energy (IE) on Al-Si-Mg-Cu alloy casting with reference to inclination to rolling direction are discussed in this article. The results show that rolled and quenched (CQ) sample possess superior UTS and HD to as-cast and those of rolled and aged samples (CA). Improved IE resistance with ductility is shown by both CQ and CA samples. However, these mechanical properties are enhanced as changes in the test sample direction moved away from rolling direction for all heat-treated samples. The CQ samples displayed highest tensile strength (108 MPa) and PE (19.8%) in the 90 direction.
- ItemOpen AccessApplication of a New Iterative Method To Analysis of Kinetics of Thermal Inactivation of Enzyme(U.P.B. Scientific Bulletin, 2018) Sobamowo, M.G; Adeleye, O.AIn this paper, a new iterative method proposed by Temimi and Ansari is applied to analyze the kinetic of thermal inactivation of jack bean urease (EC3.5.1.5). The analyzed kinetics or reaction mechanisms consist of three-reaction steps and included the Arrhenius equation for the temperature dependence of rate constants as well as the temperature change in the initial heating period. The obtained solutions are used to study the model parameters on the kinetics of thermal inactivation of enzyme. The analytical solutions are verified with numerical solutions using Runge – Kutta with shooting method and good agreements are established between the solutions. The information given in this theoretical investigation will assist in the kinetic analysis of the experimental results over handling rate constants and molar concentrations.
- ItemOpen AccessApplication of Artificial Neural Network in Breast cancer Classification : A comparative Study(Journal of Baaic Medical Sciences, 2014-06-01) Nwoye, E. O.; Nwaneri, S. C.; Iruhe, N. K.; Babatunde, A. M.6. Background: Breast cancer is a leading cause of death especially among women globally. The classification task of breast lump as benign or malignant is due to the experience and skill of the radiologist. However, Artificial Neural Networks (ANNs) can be developed to assist radiologists in decision making Objective: The purpose of this study is to develop ANN based models for breast cancer classification Methods: The five features of retrospective breast ultrasound data obtained from Lagos University Teaching Hospital (LUTH) consisting of 83 samples were rated using Breast Imaging Reporting and Data system (BI-RADS). The data was normalized and trained in MATLAB software version (R2009a) using a feedforward multilayer ANN with 5 inputs neurons, 10 hidden neurons and one output neuron. The hidden neurons wee increased in steps of 10 for different iterations to a maximum of 100 neurons in the hidden layer. The well known Wisconsin Breast Cancer Data (WBCD) comprising of digitized data was also trained with the same algorithm and parameters Result: The results show that ANNs performance in both cases was quite high. It was also proved that there was no direct relationship between the performance of the network and the number of hidden neurons. Conclusion: ANNs are different classifiers that can be utilized in the diagnosis of breast cancer in the country.