Covenant Journal of Engineering Technology (Special Edition) <p>CJET is a peer-reviewed, Open Access multidisciplinary engineering journal that publishes original research articles as well as review articles in all areas of engineering technology. It publishes both theoretical and experimental high-quality papers of permanent interest, not previously published in journals, in the field of engineering technology. In addition to peer-reviewed original research papers, the Editorial Board welcomes original research reports, state-of-the-art reviews and communications in the broadly defined field of engineering science and technology.</p> en-US (Engr. Imhade P. Okokpujie) (webmaster) Tue, 18 Sep 2018 11:22:34 +0000 OJS 60 Finite Element Analysis of Displacement and Von-Mises Stress in Cylindrical Liquified Petroleum Gas Pressure Tank <p class="AuthorEmail">Increase in demand of liquefied petroleum gas (LPG) has led to development of LPG facilities throughout the world. The limitation of ASME standard in the design of pressure vessels and reoccurring cases of gas plant, gas cylinder explosions led to this research. In this research, finite element method was used to investigate the displacements, deflections and Von-Mises stresses in a cylindrical liquefied petroleum gas pressure tank with respect to plate thickness at different operating pressures and ambient conditions. A cylindrical pressure tank made of ASTM A516 Grade 70 with thickness; 2mm, 5mm, 10mm, 20mm and 30mm was selected for the analysis with plain strain condition assumptions. ANSYS was used to generate the mesh model of the liquefied petroleum gas pressure tank and conduct the finite element analysis. The displacement, deflection and Von-Mises stress showed an inverse relationship with the tank section shell thickness while varying the LPG pressure; 0.5MPa at 20<sup>0</sup>C, 0.91MPa at 40<sup>0</sup>C and 1.55MPa at 60<sup>0</sup>C respectively. It was also observed that the factor of safety showed a linear relationship with increasing shell thickness. For each operating pressure, a minimum shell thickness was deduced. This minimum thickness was at a Von-Mises stress which falls below the materials yield stress and allowable stress. Therefore, the vessel will not fail once operated at or above the minimum pressure tank shell thickness. The effect of weldment along the seams of vessel was not carried out in this research work. Sharp edges are stress raisers, also there is possibility of stress been developed at the inlet and exhaust valves of the pressure tank. The effect of stress at this points on the vessel were not considered for this research work.</p> C.U. Ugochukwu, O.O. Oluwole K.M. Odunfa Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 Solid State Fermentation of Orange Pomace for Bioethanol Production <p class="AuthorEmail">This study is aimed at studying the effect of process variables on solid state fermentation of orange pomace for bioethanol production using <em>Saccharomyces cerevisiae.</em> The effect of substrate concentrations (100 - 350 g), fermentation period (24 - 72 hours) and inoculum amount (2.0 - 4.5 g) on solid state fermentation of orange pomace for bioethanol production was investigated. Characterization of the resulting bioethanol was carried out to determine its fuel properties (viscosity, flash point, density, refractive index, specific gravity, pH and boiling point). Experimental results revealed increase in the process variables (substrate concentration, fermentation period and inoculum amount) led to a corresponding increase in bioethanol yield until an optimum condition was reached (substrate loading of 200 g, pH of 4.5, fermentation temperature of 35°C, inoculum amount of 3 g and fermentation period of 72 hours) after which a decline in yield was observed. The maximum ethanol yield of 32.32 % v/v was obtained at these condition. Characterization of the bioethanol sample showed that the ethanol has satisfactory fuel properties that establishes its suitability as an alternative renewable fuel that can be blended with gasoline.</p> U. Musa, I. A. Mohammed, S. M. Munnir, M.U.Garba,, A.F. Abdulhamid & E.P Uduak Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 Effect of Curing Water Qualities on Compressive Strength of Concrete <p>The strength development and durability of concrete can be influenced by the quality of water used for curing the concrete. Consequently, this study was aimed at investigating the effect of contaminating the water for curing concrete on its compressive strength. Raw (tap) water and a water cement ratio of 0.6 were used in the production of the concrete cubes of 50 mm x 50 mm x 50 mm. The concrete samples produced were cured in raw water and water contaminated with varying percentages (25, 50 and 100%) of wastewater collected from a wastewater stabilisation pond. Chemical analysis was carried out to determine the pH, total dissolved solids (TDS), chloride, hardness, alkalinity, salinity, temperature and conductivity of the wastewater. The results of chemical analysis showed that these parameters are higher in the wastewater samples than in the raw water samples. The compressive strength of the concrete cubes were determined after 1, 3, 7, 14, 28, 60 and 90 days of curing. The compressive strength of concrete samples immersed in raw water, shows there was a progressive decrease in the strengths of the samples immersed in contaminated water as the percentage of the wastewater increased. Therefore, it is recommended that concrete that will be in contact with wastewater or sewage-polluted water should have been cured in uncontaminated water that gives assurance of maximum strength development. for the compressive strength of concrete cured in raw water, for 28 days the compressive strength of concrete in 25% waste H<sub>2</sub>O + 75% rawH<sub>2</sub>O, 50% waste H<sub>2</sub>O + 50% rawH<sub>2</sub>O and 100% wastewater content decrease by 12.35%, 25.44%, 35.74% respectively.</p> O.A. Dauda, J.O. Akinmusuru, A.M. Dauda, O.S.I. Fayomi & T.O. Durotoye & T.O. Durotoye Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 Theme: Renewable Energy and Sustainability Experimental and Numerical Study of Drying of Moringa Oleifera Leaves <p>Drying is a preservation technique to reduce the water content of the food product to a safe level and to minimize biochemical reactions of the degradation and also to increase the shelf life of the product. Moringa being an agricultural product of high chemical, nutritional and medical use is susceptible to degradation due to relatively high moisture content. Moringa leaf is sensitive to sunlight, therefore, forced convection drying method with two types of air velocities (2.2 and 1.2 m/s) was employed in its drying. A batch of moringa leaves of 200g by mass having an initial moisture content of 83% wet basis was dried to desired 14% wet basis moisture content at average temperature of 40oC. Drying chamber and ambient temperatures, relative humidity, air flow velocity and rate of weight reduction were measured. The experimental and model results were statistically validated. Also numerical modeling of heat and mass transfer that occurred in the drying process was done using COMSOL Multiphysics 4.3b that uses finite element approach. It took between 10 and 12 hours to dry moringa leaves to the desired moisture content at drying air velocity 2.2 m/s and 1.2 m/s respectively. The results predicted from the modelling when compared with the experimental data have a considerably agreement.</p> O. S. Olaoye, A. Alausa & O. Onihale Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 Waste Cooking Oil Methyl Ester: Transesterification and Evaluation of Corrosion Rates of Aluminium Exposed to Blended Biodiesel and Automotive Gas Oil <p class="AuthorEmail">This study investigated the corrosion of aluminum exposed to biodiesel produced from Waste Cooking Oil (WCO) and Automotive Gas Oil (AGO) blends. Response Surface Methodology (RSM) with three level-three factor central composite design was used in investigating the effects of transesterification variables such as reaction time, catalyst amount and oil/methanol molar ratio on the yield of waste cooking oil methyl ester (WCOME). Reaction time between 40 - 80 min., catalyst amount of 0.5 - 1.5% wt. and methanol to oil molar ratio of 4 - 8 were used in the transesterification experiment. Optimization of process variables was done using RSM. The fuel properties of biodiesel at optimum level in terms of density, kinematic viscosity, flash, pour and cloud points and sulphur content were obtained using standard method as described by ASTM. Blends of WCO biodiesel 0, 10, 20, 40 and 100% of AGO were designated as B0, B10, B20, B40 and B100 respectively. Corrosion characteristics of blends on aluminium (Al) were studied by static immersion test at room temperature. Mechanical properties of the Al were investigated before and after corrosion test. Changes in the morphology of coupons were also investigated. The optimization technique predicted WCOME yield of 97.1% at the optimal level of 78 minutes, 5.99, 1.1% wt. for the reaction time, methanol to oil molar ratio and catalyst amount respectively. The fuel properties at the optimal level were within the limits specified by ASTM D6751 and EN 14214 standards. The ranges of corrosion rates obtained for the blends were 0-0.2830 mpy. The Brinell hardness ranged for the blends were 105.012, 109.177, 133.717, 155.393, 166.803 N/mm<sup>2</sup> while the tensile strength for the blends were 371.20, 386.12, 484.62, 495.22 and 592.89 MPa for B0, B10, B15, B20, B40 and B100 respectively. As the percentage of biodiesel in the blends increased, crack and pits on the morphology of the coupons become pronounced. The blend B10 was detected to perform close to B0 with respect to the Brinell hardness and tensile strength. </p> Olusegun D. Samuel & Taofeek A. Yusuf Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 Viability of Recycled Concrete Waste as Construction Material for a Sustainable Environment <p>A major source of environmental burden in construction industries is concrete waste because its generation and accumulation start from the time fresh concrete are produced on-site or off-site till its hardens. This made concrete the largest portion of solid waste stream by weight in the construction industries. Recycling of these waste materials into new form as well as appropriate reuse could therefore conserve natural resources, reduce the space required for land filling and the cost of transportation. This paper assesses the viability of reusing aggregates obtained from concrete waste collected from four different construction sites by comparing compressive strength of concrete made with the recycled concrete waste aggregate with concrete made with natural fresh aggregate as control specimens using an aggregate size not greater than 25mm. A total of 60 cubes of size 150mm x 150mm were cast and cured for different maturity age of 7, 14, 21 and 28 days before crushing. Laboratory results revealed that there was little variation in strength as the cubes matures. Average compressive strength of concrete made with recycled concrete waste aggregates obtained from two of the site were 22.8 N/mm2 and 24.3 N/mm2 and these were almost the same with the control test cubes with average compressive strength of 24.4 N/mm2. However, test cubes obtained from the other two sites had concrete strength lower than 20 N/mm2. Hence, concrete produced with recycled concrete waste aggregate though exhibiting lower compressive strength could be used for walkways and kerbs production in road construction, backfilling, and in concrete production for light load bearing structural components so as to achieve a sustainable environment and conserve natural resources.</p> Olaoye R. A., Oluremi J.R., Ajamu S.O. & Abiodun Y.O. Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 Use of Bamboo and Earth Materials in Construction for the Provision of Affordable Building Structures for Sustainable Development at Kuje Area Council, Abuja <p>The study was carried out on the use of bamboo and earth materials in building construction in provision of affordable housing at Kuje area council Abuja. The purpose of the study was to determine the status of the use of bamboo and earth materials in construction at Kuje area council Abuja, identifying the factors limiting the use of bamboo and earth materials in construction at Kuje area council Abuja, examine the strategies that will improve the use of bamboo and earth materials in construction at Kuje area council Abuja. Three research questions and three hypotheses were formulated to guide the study. A population of 80 respondents, comprising of 20 engineers and 60 craftsmen was used for the study. A structured questionnaire was developed by the researcher and was used as an instrument for data collection. The instrument was validated by three lecturers in the department of industrial and technology education, federal university of technology Minna. The data collected was analyzed using mean and standard deviation, while t-test statistic was used to test three hypotheses at 0.05level of significance. The findings of the study revealed that there are limitations in the use of bamboo for building construction in the Kuje Area Council. Based on the findings of the study, it was recommended that the use of bamboo and earth materials in building construction should be introduced as part of the curriculum for construction education at both undergraduate and postgraduate levels in order to sensitize the students to their potential uses and benefits. The government should employ a policy of adapting bamboo and earth materials that require minimal amounts of capital and foreign exchange and makes use of available raw materials and skills in small-scale operations and suggestion were also made for further research works.</p> Kareem W. B., Okwori R. O, Hassan A. M., Mohammed B. M, Abubakar H. O. & Dada J. A. Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000 E-version <p>All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any meams, electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without the prior written permission of the publisher.</p> Editor-in-Chief: Dr. Olugbenga Omotosho, Managing Editor: Edwin O. Agbaike Copyright (c) 2018 Covenant Journal of Engineering Technology (Special Edition) Tue, 18 Sep 2018 00:00:00 +0000