Faculty of Engineering
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Item Chemical and Mechanical Properties of Reinforcing Steel Bars from Local Steel Plants(Springer, 2019-06-06) Jamiu Kolawole Odusote; Wasiu Shittu; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Olumide AdeyemoSteel bars are important engineering materials for structural application. In Nigeria, due to incessant building collapse occurrences, it is important to further investigate some of the mechanical and chemical properties of reinforcing steel bars produced from scrap metals in order to ascertain their compliance with the required standard. Three diameters (10, 12 and 16 mm) of the reinforcing steel bars were chosen from each of the eight steel plants (A–H). Chemical composition analyses and mechanical tests (yield strength, ultimate tensile strength and percentage elongation) were performed using optical emission spectrometer and Instron Satec Series 600DX universal testing machine, respectively. Hardness values of the samples were obtained by conversion of tensile strength based on existing correlation. The results showed that carbon contents, hardness values, yield and ultimate tensile strengths of some of the steel bars were found to be higher than the BS4449, NIS and ASTM A706 standards. The steel bar samples were also found to possess good ductility with samples from steel plants C and D. By observation, all the 12 mm steel bars from steel plants A to H met the required ASTM and BS4449 standards except samples from plant G. This study revealed that most of the investigated reinforcing steel bars have reasonable yield strength, ultimate tensile strength, ductility and hardness properties when compared with the relevant local and international standards. Therefore, they are suitable for structural applications where strength and ductility will be of paramount interestItem Assessment of Suitability of Nigerian Made Steel Bars for Structural Applications(The Journal of the Association of Professional Engineers of Trinidad and Tobago, 2016-10-02) Abdul Ganiyu F. Alabi; Akintunde O. Ayoade; Jamiu Kolawole Odusote; Adekunle Akanni AdelekeThe mechanical properties of selected reinforcing steel bars produced from two rolling mills in Osun State, Nigeria were studied. An optical emission spectrometer was used for chemical composition analysis while the tensile test was carried out using a Universal Testing Machine. Izod v-notched was used for impact test, while the hardness values were obtained from Brinnel hardness tester. Scanning Electron Microscope was used for the fractured surface fractography. The Ultimate Tensile Strengths (UTS) of all the samples are higher than BSS4449:2005+A2:2005 standard and are also in close proximity to A707M-15 standard. Samples A12, B10 and B12 possessed higher yield strengths than samples A16 and B16 but lower than those of BSS4449:2005+A2:2005 and A707M-15 standards. Ductile property of the samples doubled the recommended Nst-65-Mn standard values while the hardness and ductility properties are higher than the recommended A707M-15 and BS4449 standards. The results showed that the investigated reinforcing bar samples possessed reasonably high strength and ductility when compared with available standards. Consequently, these bars would be suitable for structural applications where strength and ductility are critical properties. They would also be used in steel reinforcement applications that would require continuous and repetitive loading such as in buildings and bridges.Item Mechanical properties and microstructure of precipitation-hardened Al-Cu-Zn alloys(UMP Publisher, 2015-12-30) Jamiu Kolawole Odusote; Adekunle Akanni Adeleke; P. A. AjayiMany automobile components are made from aluminium and its alloys because of their suitable properties. Metals and their alloys are usually subjected to heat treatment in order to improve their properties. Thus, the effect of precipitation hardening on the mechanical properties and microstructure of sand cast aluminum alloys was investigated. The cast AlCu-Zn alloy samples were heat-treated at 460 °C for 2 hours, quenched in water and then age-hardened at 160 °C for 5 hours. Tensile, impact and hardness tests were carried out on the heat-treated and the as-cast Al-Cu-Zn alloys samples. The surface morphology of both the as-cast and the precipitation hardened samples was observed using digital metallurgical microscope. The ultimate tensile strength of the precipitation hardened samples A2 (81.2Al: 1.56Cu: 8.33Zn) and B2 (81.7Al: 3.25Cu: 6.16Zn) are 173.42 N/mm 2 and 168.02 N/mm 2 , respectively. These values are higher than those of the as-cast samples A1 and B1, which are 168.02 N/mm 2 and 157.84 N/mm 2 , respectively. The precipitation hardened Al alloy samples also displayed higher hardness, impact energy and elongation than the as-cast samples, indicating improved properties. The presence of coarse reinforcing intermetallic phases was observed in the as-cast samples as compared to the well-distributed fine grain size microstructure of intermetallic phases in the precipitation hardened samples. It can be concluded that precipitation hardening improves the mechanical and microstructure properties of aluminum alloys and thus will find wider applications in automobile industries for the production of components and parts.Item Mild pyrolytic treatment of Gmelina arborea for optimum energetic yields(Taylor and Francis, 2019-03-17) Adekunle Akanni Adeleke; Jamiu Kolawole Odusote; O. A. Lasode; Peter Pelumi Ikubanni; M Malathi; Dayanand PaswanOne of the most promising routes to produce solid biofuel from biomass is mild pyrolytic treatment (torrefaction). In the present study, mild pyrolytic treatment of Gmelina arborea was carried out to obtain optimum energetic yields (mass yield, higher heating value and energy yield). The biomass of 0.5–6 mm particle sizes were torrefied at two different temperatures, 240 and 300°C for residence time of 30 and 60 min. Full-factorial experimental method was used for the optimization of torrefaction conditions in order to produce solid fuel with high energetic yields. The analyses revealed that torrefied biomass was better in terms of heating value, proximate contents and fuel ratio. The results also showed that temperature has the largest effect on the energetic yields compared to residence time and particle size. The optimum torrefaction conditions that produced the highest energetic yields were temperature of 260°C, residence time of 60 min and particle size of 2 mm as predicted using the factorial linear models. The optimum conditions were experimentally validated and the energetic yields obtained were acutely close to those predicted using factorial linear models developed in this study. Hence, mild pyrolytic treatment at a temperature of 260°C, residence time of 60 min and particle size of 2 mm is useful to produce solid biofuel with maximum energetic yields.Item Evaluation of the Mechanical Properties of Reinforcing Steel Bars from Collapsed Building Sites(ASM, 2013-08-27) Jamiu Kolawole Odusote; Adekunle Akanni AdelekeMechanical properties of reinforcing steel bars obtained from three different collapsed building sites in Lagos, Nigeria were examined. An optical emission spectrometer was used for chemical composition analysis while the tensile test was carried out using a Universal Testing Machine. The yield strength of the steel bars was found to be higher than BS4449 (GRADE 460B), Nst.65-Mn, and ASTM A706 standards, while their percentage elongations were lower than most of the standards. The steel bars used at the Sango collapse site have higher UTS compared with the standards, while those used at Ilesanmi and Ewuntun collapse sites have UTS values that are in close range with the standards. The reinforcing bar obtained from Ilesanmi collapsed site has higher percentage elongation than ASTM A706 standard but lower than Nst.65-Mn and BS4449 (GRADE 460B) standards. The bars obtained from Sango and Ewuntun collapse sites displayed lower percentage elongation compared with that from Ilesanmi site. All the investigated reinforcing bars possessed reasonably high strength with low ductility. Thus, these bars are susceptible to brittle fracture, which might have contributed to the collapse of the building structures.Item ANALYSIS OF PROPERTIES OF REINFORCING STEEL BARS: CASE STUDY OFCOLLAPSED BUILDING IN LAGOS, NIGERIA(Trans Tech Publications, 2012-02-02) Jamiu Kolawole Odusote; Adekunle Akanni AdelekeThe chemical compositions and the microstructures of reinforcing steel bars obtained from three different collapsed building sites were studied. Optical emission spectrometer was used to carry out the chemical analysis, while the microstructure was examined using an optical microscopy. The carbon contents of the steel bars were found to be higher than BS4449 and ASTM706 standards, but they are in close range with the Nst-65-Mn standard. The manganese contents of the steel bars are lower, while the sulphur and phosphorus contents are quite higher than the BS4449, ASTM706 and Nst-65-Mn standards. The hardness values of the investigated bars are higher than recommended BS4449 standard but lower than Nst-65-Mn standard. Brittle globules of Fe3P and FeS were observed within the structure possibly due to higher contents of deleterious sulphur and phosphorus. The results suggest that the investigated reinforcing bars are brittle and thus contributing significantly to the collapse of the building structures.Item Physical Properties of Biomass Fuel Briquette from Oil Palm Residues(JASEM, 2017-06-18) H.O. Muraina; Jamiu Kolawole Odusote; Adekunle Akanni AdelekePalm Kernel Shell (PKS) and Mesocarp Fibre (MF) were used for the production of fuel briquettes in this study in order to supplement the energy mix of the nation. PKS was pulverized and then sieved into different grain particles of 350 μm, 250 μm and 150 μm, before mixing with MF in the ratios: 90:10, 80:20 and 70:30 (PKS: MF respectively). Cassava Peel (CP) was used as binder for the briquettes. A 200 kN force was exerted during densification while the waiting time for the briquettes to properly form was 120 seconds. Proximate/physical analysis was carried out and the results showed that briquette series of 150 μm (80:20) has the minimum moisture content of 6.00 % while series 350 μm (90:10) recorded the lowest ash content of 1.50 %. Volatile matter of 72.80 % was recorded from series 150 μm (70:30) as the highest of all the series produced. Briquette series of 350 μm (70:30) have the highest fixed carbon and calorific value of 19.90 % and 18.1063 kJ/g, respectively. The results showed that the fuel briquettes from PKS and MF (especially 350 μm series) could serve as alternative source of energy for domestic and industrial applications. Keywords: Palm kernel shell; Mesocarp fibre; Briquette; Biomass solid fuel; proximate analysis.Item INFLUENCE OF TORREFACTION ON LIGNOCELLULOSIC WOODY BIOMASS OF NIGERIAN ORIGIN(Journal of Chemical Technology and Metallurgy, 2019-02-02) Adekunle Akanni Adeleke; Jamiu Kolawole Odusote; Paswan Dayanand; Lasode Olumuyiwa Ajani; Malathi MadhuraiTorrefaction process is a thermal treatment that can improve quality of lignocellulosic biomass into a carbon-rich and hydrophobic feedstock which is applicable as fuel and metallurgical reductant. Biomass (Melina and Teak wood) of Nigerian origin was subjected to mild (240o C) and severe (300o C) torrefaction treatment at different residence times (30 and 60 min) and particle sizes (+0.5 - 2 mm and +4 - 6.35 mm). Raw biomass and biochar from torrefaction were subjected to proximate, ultimate, higher heating value and SEM analyses. The mass yield obtained for mild treatment conditions for both biomass was in the range of 72 - 84 (wt. %) compared to 40 - 54 (wt. %) under severe treatment conditions. However, 33 - 56 % increment in higher hating value was observed for severe treatment conditions as against 11 - 17 % of mild treatment condition. This ultimately led to a 60 - 72 (wt. %) energy yield for severe treatment conditions and 73 - 94 (wt. %). The fixed carbon content increased from the range of 8 - 11 (wt. %) to 20 - 61 (wt. %) after torrefaction. The volatile matter content under mild condition was reduced by 7 - 10 % for both biomass as against 41 - 47 % under severe treatment condition. The fuel ratio increased from 0.11 and 0.15 for Melina and Teak woods respectively to a range of 0.22 - 0.25 for mild treatment conditions and 0.97 - 1.75 for severe treatment condition. The H/C and O/C atomic ratios of biochar were lowered towards that of sub-bituminous coal and peat. A honey-comb-like structure with cylindrical holes were observed for biochar compared to the fibrous and spongy nature of the raw biomass. Biomass of Nigerian origin were improved under torrefaction and thus can be suitable as feedstock in thermal or metallurgical applications.Item Microstructural assessment of AISI 1021 steel under rapid cyclic heat treatment process(Elsevier, 2019-10-13) Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; T. A. Orhadahwe; J.O. Aweda; Jamiu Kolawole Odusote; O.O. AgboolaThis research was aimed at using image analysis to describe the effects of rapid cyclic heating on mild steel. AISI 1021 steel sample used in this study was subjected to quenching heat treatment followed by 1, 2, 3, and 4-cycles of rapid heat treatment. The as-treated steel samples were characterized by Brinell hardness tests, Charpy V-notch impact tests, optical microscopy, and image analysis using Image J software. The results revealed that the grain size decreased from 1.07 μm in the control sample to 0.79 μm in the third cycle sample and increased to 0.86 μm in the fourth cycle sample. However, the results revealed that two-cycles of rapid heat treatment was enough to produce ultra-fine grains and impact ductility in mild carbon steel. Keywords: Mechanical properties, Collapsed building, Steel rods, Chemical compositions, Percentage elongationItem Preliminary Characterisation of Iron Ores for Steel Making Processes(Elsevier, 2019-08-14) Jamiu Kolawole Odusote; Adekunle Akanni Adeleke; Bankole Sheriffdeen Ameenullahi; Adeolu Adesoji AdediranIron ore is one of the major raw materials required to produce iron and steel products. However, there is a need to characterise the iron ore to determine their grade based on the iron and other mineral contents before usage. In this study, iron ores from Jaruwa and Agbaja deposits were characterised using X-ray diffractometer, X-ray florescence spectrometer, scanning electron microscope and petrographic microscope. Phase identification and chemical compositions revealed that the iron ore content of the Jaruwa deposit is higher (68%) than that of the Agbaja deposit (53%). The phosphorus contents of both deposits are higher than 0.04% recommended for high grade iron ore. Iron ore from Agbaja deposit contains more silica and alumina than Jaruwa deposit. A spherical ooids (concentric layer) that shows partial and whole replacement by hematite (iron precipitates around a nucleus) was observed on the petrograph of Agbaja ore as against the more dark areas which signified more iron contents in Jaruwa iron ore. Based on the findings, Jaruwa deposit can be classified as high grade hematite iron ore while Agbaja deposit can be classified as lean grade, although both can serve as feedstock for production of iron through direct reduction route.