Faculty of Engineering
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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 Effect of copper addition and solution heat treatment on the mechanical properties of aluminum alloy using formulated bio-quenchant oils(Engineering and Applied Science Research, 2020-01-01) Adekunle A.S.; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Omoniyi P. O.; Gbadamosi T. A.; Jamiu Kolawole OdusoteAddition of copper and use of solution heat treatment solution with bio degradable vegetable oils as quenchants has great potential to improve the mechanical properties of aluminum and its alloys. In this study, copper was added to as-received Al- Si-Mg alloy to produce Al-Si-Cu-Mg alloy. The specimens were quenched with blended bleached bio-quenchant oils and a petroleum-based oil after solution heat treatment. The alloy was heat treated at 500℃, soaked for 20 minutes in a muffle furnace before quenching in the formulated bio-quenchant oils. The cooling properties, mechanical properties and microstructure of the solution treated specimens were determined. Blended bleached melon (BBM) oil was observed to have offered a higher cooling rate of 49.3 ℃ s-1 compared to the petroleum-based (PB) oil with a cooling rate of 25.8 ℃ s-1. Blended bleached melon oil exhibited the highest quench severity value of 1.0074 m-1, while petroleum-based oil was 0.6133 m-1. The as-received alloy and as-cast alloy specimens exhibited tensile strength values of 125.33 and 131.37 N mm-2, respectively, while a higher tensile strength value of 139.30 Nmm-2 was obtained using the blended bleached melon oil. The highest Rockwell hardness number, 61.00 HRB, was obtained using blended bleached melon oil. The overall mechanical properties of specimens improved after the addition of copper and heat treatment in various bio-quenchant oilsItem Influence of temperature on the chemical compositions and microstructural changes of ash formed from palm kernel shell(Elsevier, 2020-09-30) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; Adediran, A.A; O.S. AdesinaThis study investigated the characteristics of raw palm kernel shell (raw PKS) and the influence of temperature variation on palm kernel shell ash (PKSA). The PKSA was obtained under different temperature regimes of 900, 1000, and 1100°C. The characterization of the samples was carried out using X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) with attached Energy Dispersive X-ray (EDX) facilities. The results showed that moisture and ash contents and the density of raw PKS were 6.56%, 8.86%, and 745 kg/m3, respectively. The colour of the pulverized PKS was dark brown, as observed by visual examination based on standard colour gradation. This colour transformed into various shades of brown when PKS was subjected to different temperature regimes to form PKSA. The XRF analysis showed that silica is the main constituent of the raw PKS and PKSA samples. Silica content in the PKSA increased with the rise in the heating temperature. The FTIR and EDX spectra confirmed the predominance of silicon compounds with functional groups associated with silanol and siloxane. Also, XRD analysis revealed that the silica contents in the samples are quartz, while SEM examinations indicated that temperature increases during processing influenced the microstructure through the reduction of pore concentration in the samples. The silica obtained from the PKSA would find applications in metal matrix composites as partial reinforcing materials.Item Magnesium inclusion effect on Al-Zn-Cu alloys: A study on microstructure and mechanical properties(Elsevier, 2021-04-14) Jamiu Kolawole Odusote; Adekunle Akanni Adeleke; S.A. Muraina; Peter Pelumi Ikubanni; Ibrahim Momoh-Bello OmiogbemiThe microstructure and mechanical properties of Al-Zn-Cu alloy with magnesium inclusion varying between 0.5 and 1.5 wt% were explored in this investigation. Al-Zn-Cu-Mg alloy was prepared by sand casting. Heat-treatment was done on the cast alloy samples at 460 °C for 2 h, which was then water-quenched. The samples at 160 °C were age-hardened for 5 h. Mechanical tests were done on both the heat-treated and as-cast alloy samples. Optical and scanning electron microscopy were used for the surface morphology of the samples. The maximum tensile strength (178.04 N/mm2) and hardness value (42.49 HB) were obtained from the Al-Zn-Cu-Mg alloy samples with 0.33 wt% Mg and 0.001 wt% Mg, respectively. In the as-cast samples, the reinforcing intermetallic phases present was coarse in nature while the precipitation hardened samples showed well-distributed reinforcing intermetallic phases which are fine grain size. Hence, the tensile strength of the cast Al-Zn-Cu-Mg alloy was positively influenced with the addition of magnesium while precipitation hardening eliminates micro segregations, thus, Al-Zn-Cu-Mg alloy mechanical properties were improved. Thus, the Al-Zn-Cu-Mg alloy can be useful in automobile industry.Item Optimization of the tribological properties of hybrid reinforced aluminium matrix composites using Taguchi and Grey’s relational analysis(Elsevier, 2021-07-05) Peter Pelumi Ikubanni; Makanjuola Oki; Adekunle Akanni Adeleke; O.O. AgboolaThe tribological properties of synthesized hybrid reinforced aluminium matrix composites (AMCs) have been optimized in this study using Taguchi and grey relational analysis (GRA), methods where a L16 orthogonal array was used for the experimental design. Hybrid palm kernel shell ash (0–6 wt.%) and SiC (2 wt.%) formed the reinforcements of interest, which were combined in ratios ranging between 2 and 8 wt.%. Different loads (250, 500, 750, and 10 0 0 g) and speeds (250, 500, 750, and 10 0 0 rpm) were used as control factors. The wear samples were produced using the double-stir casting method, while a Taber type abrasion machine was used for the wear experiments. The evaluated wear index and volume loss showed that the speed and load were better influential factors on the performance characteristics of the composites than wt.% of reinforcements. The Taguchi-Grey’s relational analysis gave the optimal combination of the process parameters for both the wear index and the volume loss as A3 B1 C1 (Reinforcement = 6 wt.%; Load = 250 g; Speed = 250 rpm) and A1 B1 C1 (Reinforcement = 2 wt.%; Load = 250 g; Speed = 250 rpm), respectively. The predicted and experimental values at the optimum conditions were confirmed to be within the range based on the performance of the confirmation test. The utilization of Taguchi and GRA methods have significantly confirmed that the influence of speed as a factor of performance was higher than load, which in turn was a better influencing factor than wt.% of reinforcements