Research Articles in Mechanical Engineering
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Item Energy from biomass and plastics recycling: a review(Taylor and Francis, 2021-01-01) Samuel Oluwafikayo Adegoke; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Chiebuka Timothy Nnodim; Ayokunle Olubusayo Balogun; Olugbenga Adebanjo Falode; Seun Olawumi AdetonaThe sustainability of fossil fuel is not guaranteed as it is gradually depleting. Alternative ways to this challenge are to generate biofuel from biomass and plastic solid wastes. Many studies have been done on the actualization of these alternatives. Hence, this study accumulates research from multidiscipline for the purpose of advancing biofuel production for sustainable energy. The necessary information needed by scientists having interest in biofuel production, including government policy, biomass selection, different conversion techniques and different ASTM standards for biodiesel properties are entrenched in this study. For vast biofuel production, there is a need for a collaborative work among fields from microbiologist, biochemist to engineering for the development of innovations, growth of cells, understanding of genetic engineering of algae strains and optimization of biofuel production. Also, a review on the recovery and recycling process of plastic solid waste was done. This is to ensure that the use of plastic solid waste to support energy sustenance will lead to no energy is wasted. Various ASTM standards for investigating the different properties of bio-oil were reviewed. The numerous plastic wastes that have not been utilized in the production of biofuel can be investigated to reduce the environmental pollution.Item Pathways for the Valorization of Animal and Human Waste to Biofuels, Sustainable Materials and Value-Added Chemicals(MDPI, 2023-03-06) Jude A. Okolie; Toheeb Jimoh; Olugbenga Akande; Patrick U. Okoye; Chukwuma C. Ogbaga; Adekunle Akanni Adeleke; Peter Pelumi Ikubanni; Fatih Güleç; Andrew Nosakhare AmenaghawonHuman and animal waste, including waste products originating from human or animal digestive systems such as urine, feces, and animal manure, have constituted a nuisance to the environment. Inappropriate disposal and poor sanitation of human and animal waste often cause negative impacts on human health through contamination of the terrestrial environment, soil, and water bodies. Therefore, it is necessary to convert these wastes into useful resources to mitigate their adverse environmental effect. The present study provides an overview and research progress of different thermochemical and biological conversion pathways for the transformation of human- and animal-derived waste into valuable resources. The physicochemical properties of human and animal waste are meticulously discussed as well as nutrient recovery strategies. In addition, a bibliometric analysis is provided to identify the trends in research and knowledge gaps. The results reveal that the U.S.A, China and England are the dominant countries in the research areas related to resource recovery from human or animal waste. In addition, researchers from the University of Illinois, the University of California Davis, the Chinese Academy of Science and Zhejiang University are front runners in research related to these areas. Future research should be centred on developing technologies for the on-site recovery of resources, exploring integrated resource recovery pathways, and exploring different safe waste processing methods.Item Corrosion rates of green novel hybrid conversion coating on aluminium 6061(Elsevier, 2020-08-19) Makanjuola Oki; A.A. Adediran; Peter Pelumi Ikubanni; O.S. Adesina; Adekunle Akanni Adeleke; S.A. Akintola; F. Edoziuno; A. AleemThe use of chromate conversion coatings have been limited by several protocols as a result of their carcinogenicity and toxicity towards humans and the environment. Searches are ongoing for chromate replacement in coating baths and processes. This paper describes the comparison among the corrosion rates of a novel hybrid conversion coating derived from water extracts of hibiscus sabdariffa calyx in conjunction with ammonium molybdate, a molybdate conversion coating and the so-called chromate conversion coating. Potentiodynamic polarization measurement in 3.5 wt% sodium chloride solution was employed in ranking the coatings as sabdariffa molybdate being more corrosion resistant than chromate, which in turn out performed molybdate.Item 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 Tumbling strength and reactivity characteristics of hybrid fuel briquette of coal and biomass wastes blends(Elsevier, 2021-04-04) Adekunle Akanni Adeleke; J.K. Odusote; Peter Pelumi Ikubanni; O.O. Agboola; A.O. Balogun; O.A. LasodeThis paper presents an assessment of the tumbling strength and reactivity behaviour of hybrid fuel briquette (HFB) produced from coal and torrefied woody biomass wastes. Briquettes were produced using 97% coal and 3% torrefied biomass with the blend of pitch and molasses in different ratios as a binder. The briquettes were treated in an inert environment at 200–300 °C for a residence time of 60 and 120 min in a tubular furnace. Fourier Transform Infrared Spectrophotometer (FTIR) was used to obtain the functional groups in the raw materials and the HFB. HFB were exposed to tumbling test (TSI+3mm) after curing and high temperature (1200 °C) exposure. Reactivity test (RI) of the HFB was carried out based on ASTM D5341M-14 standard. The FTIR spectra of the HFB show the presence of aromatic CC bonds and phenolic OH group. The TSI+3mm of the HFB samples drastically reduced from 95.5–98.3% for the treated to 57.4–77.4% for the samples exposed to 1200 °C. The reactivity indices of the HFB were in the range of 48–56%, which indicated that the HFB were highly reactive. Based on the TSI+3mm and RI, the HFB are suitable carbonaceous material in direct reduced iron making through rotary kiln.Item Comparative Analyses of the Inhibitive Influence of Cascabela thevetia and Jatropha curcas Leaves Extracts on Mild Steel(Nature Environment and P ollution Technology, 2020-09-04) A. S. Adekunle; Adekunle Akanni Adeleke ; Peter Pelumi Ikubanni; O. A. AdewuyiThe inhibitive properties of the extracts of Cascabela thevetia and Jatropha curcas were comparatively studied on corrosion of mild steel in H2SO4 acid. The extracts of both plants contained active phytochemical constituents such as tannins, saponins, alkaloids, flavonoids, terpenes and phenols which made them useful as good corrosion inhibitors. The extract concentrations were varied from 0.3 to 1.5 g/L during both the gravimetric and gasometric analyses for an exposure time of 7-28 days. The weight loss of the coupon, corrosion rate, surface coverage and inhibitive efficiency was evaluated for both the extracts. The results of the gravimetric and gasometric analyses indicated that inhibitive efficiency increased with an increase in the concentration of inhibitors and the highest was 55.77% for Jatrophas curcas at the concentration of 1.5 g/L. The weight loss was a little lower for Cascabela thevetia (4.36 g) compared to Jatrophas curcas (4.66 g) at the highest exposure time used (28 days). Cascabela thevetia has a better surface coverage (0.68) than Jatropha curcas (0.61), hence, Cascabela thevetia inhibits better for a 7-day exposure time. However, when the mild steel was further exposed for more than 7 days, Jatropha curcas exhibited a better inhibitive property. The highest and least hydrogen gas evolution was obtained at 0.3 g/L concentration (7 minutes) and 1.5 g/L concentration (1 minute) for both Cascabela thevetia and Jatropha curcas leaves extracts, respectively. Based on the results, the utilization of extracts of Cascabela thevetia and Jatropha curcas leaves as replacements for toxic organic inhibitors in industries are recommended.Item Physico-chemical characterization, thermal decomposition and kinetic modeling of Digitaria sanguinalis under nitrogen and air environments(Elsevier, 2021-06-12) Ayokunle O. Balogun; Adekunle Akanni Adeleke ; Samuel Oluwafikayo Adegoke; Armando G. McDonald; Peter Pelumi Ikubanni; Abdulbaset M. AlayatThe study undertook the thermal degradation of a tropical grass species, Digitaria sanguinalis, in nitrogen (pyrolysis) and air (combustion) atmospheres through thermogravimetric analysis as well as comparative kinetic investigation. The differential (Friedman) and integral (Flynn-Wall-Ozawa and Straink) isoconversional methods in conjunction with the Coats-Redfern method were utilized. This was to obtain the kinetic parameters and also predict the probable reaction mechanisms involved in the decomposition process. Before the thermal and kinetic investigations, the grass was analyzed for its physical, chemical, and structural properties utilizing diverse wet-chemistry and spectroscopic techniques. This research attempt is part of a larger project designed to investigate a couple of local grass species, which are invasive by nature, as potential energy crops for pyrolytic and combustion applications. The grass had a fixed carbon content of 17.85% and a calorific value of 13.7 MJ kg−1. The fatty acids detected were from C12 (lauric acid) to C24 (lignoceric acid), with the three most abundant being palmitic (94 mg/g extract), linoleic (27 mg/g extract), and oleic (19 mg/g extract) acids. The average residual weight in air (25.3%) was relatively less than in nitrogen (38.7%), affirming the higher rate of reaction in an oxidative process (combustion). The activation energy profiles in both atmospheres were markedly different, as shown by the Flynn-Wall-Ozawa technique for a conversion ratio of 0.1–0.2 (nitrogen, 149 kJ/mol; air, 177 kJ/mol) and 0.65–0.8 (nitrogen, 366 kJ/mol; air, 170 kJ/mol). Of all the models tested, the model-fitting technique indicates that the chemical reaction and diffusional models play predominant roles in the thermal decomposition of the grass under investigation. The thermal degradation of Digitaria sanguinalis proceeded mainly as complex multi-step reaction mechanisms. Aside from the potential suitability of the grass species for bioenergy applications and biofuels production, it also demonstrated huge capability for biochemical extraction. Future work will incorporate the kinetic data for the associated thermochemical processes development, and the design and optimization of reactors/combustors.