Browsing by Author "Owoseni, Tunji Adetayo"
Now showing 1 - 7 of 7
Results Per Page
Sort Options
- ItemBioinspired Design(Trans Tech Publications Ltd., 2015-12-31) Owoseni, Tunji Adetayo; Olukole, S. G.; Gadu, A. I.; Malik, I. A.; Soboyejo, W. O.Bioinspired design involves the use of concepts observed in natural biological materials in engineering design. The hope is that the leveraging of biological materials in the engineering domain can lead to many technological innovations and novel products. This work presents the initial material characterization of kinixys erosa tortoise shell using a combination of x-ray diffraction, optical/scanning electron microscopy and micro-mechanical testing. The results were used in the analytical/computational modelling of shell structures. The potential implications or the results were then discussed to give fundamental understanding of deformation and stress responses of shell structures
- ItemComprehensive passive-mode performance analysis on a new multiple-mode solar still for sustainable clean water processing(Elsevier, 2022) Abimbola Tijani Oladoyin; Takaijudin, H.; Singh, B. S. M.; Yusof, K. W.; Abdurrasheed, A. S.; Al-Qadami, E. H. H.; Isah, A. S.; Wong, K. X.; Nadzri, N. F. A.; Ishola, S. A.; Owoseni, Tunji AdetayoThe solar still is potential to augment clean water supply in the rural and low-income settlements. However, the current efficiency of the device is low. In this study, we report the fabrication and experimental performance analysis of a high-efficiency multiple-mode solar still—tagged Desal-1.5. The solar still was investigated in passive mode, relying entirely on natural insolation. Both desalination and ordinary water purification experiments were conducted on the device using seawater and moderately polluted lake water, respectively, between 09:00 and 18:00 h of Malaysia's tropic weather. The optimum freshwater yield of the prototype within the interval was 5780.5 ml/m2, while the optimum solar-to-vapor conversion efficiency, evaluated using the transient latent heat of vaporization, was 161.4%. Furthermore, for the first time on a solar still geometry, condensate loss due to condensate collection channel slope has been estimated in this study for our Desal-1.5. The loss amounted to 18.5% of the actual condensate collection. Eventually, water quality assessments of distillates from the device showed good compliance with both WHO and Malaysian drinking water standards. Thus, the recommendation of the solar still to ameliorate freshwater scarcity and support sustainable clean water provision in the rural and low-income regions is strengthened.
- ItemCompressive deformation and failure of trabecular structures in a turtle shell.(Elsevier, 2019-10-01T00:00:00Z) Ampaw, Edward; Owoseni, Tunji Adetayo; Du, Fen; Pinilla, Nelson; Obayemi, John; Hu, Jingjie; Nigay, Pierre-Marie; Nzihou, Ange; Uzonwanne, Vanessa; Zebaze-Kana, Martiale Gaetan; Dewoolkar, Mandar; Tan, Ting; Soboyejo, WinstonTurtle shells comprising of cortical and trabecular bones exhibit intriguing mechanical properties. In this work, compression tests were performed using specimens made from the carapace of Kinixys erosa turtle. A combination of imaging techniques and mechanical testing were employed to examine the responses of hierarchical microstructures of turtle shell under compression. Finite element models produced from microCT-scanned microstructures and analytical foam structure models were then used to elucidate local responses of trabecular bones deformed under compression. The results reveal the contributions from micro-strut bending and stress concentrations to the fractural mechanisms of trabecular bone structures. The porous structures of turtle shells could be an excellent prototype for the bioinspired design of deformation-resistant structures. STATEMENT OF SIGNIFICANCE: In this study, a combination of analytical, computational models and experiments is used to study the underlying mechanisms that contribute to the compressive deformation of a Kinixys erosa turtle shell between the nano-, micro- and macro-scales. The proposed work shows that the turtle shell structures can be analyzed as sandwich structures that have the capacity to concentrate deformation and stresses within the trabecular bones, which enables significant energy absorption during compressive deformation. Then, the trends in the deformation characteristics and the strengths of the trabecular bone segments are well predicted by the four-strut model, which captures the effects of variations in strut length, thickness and orientation that are related to microstructural uncertainties of the turtle shells. The above results also suggest that the model may be used to guide the bioinspired design of sandwich porous structures that mimic the properties of the cortical and trabecular bone segments of turtle shells under a range of loading conditions.
- ItemCorrugated Laterite Based Ceramic Roof Tile Stabilized with Cement(IJET Publications-UK, 2014) Kolawole, F.O.; Adeniji, S. A.; Adeyinka, T. I.; Owoseni, Tunji Adetayo; Ngasoh, O. F.; Soboyejo, W. O.The use of laterite based material as ceramic roof tile contributes to the innovation and application of local materials within our immediate environment. In this study the aim is to design and produce corrugated laterite based roof tile and investigate its water absorption and penetration. Paste of laterite-cement mix was formed with water to cement ratio of 3:1. The percentage composition of the cement used was 15% and 20%. The paste was poured into a wooden frame (dimension of 200mm x 300mm x 20mm) with an underlying corrugated metal sheet, while another corrugated metal sheet was placed on the paste to ensure formation of the corrugated shape on both sides. Water analysis carried out on the cast samples showed that the sample with 20% cement composition had a better resistance to water absorption and penetration. The result of this study indicates that the formation of corrugated roofing tile using laterite material is feasible and it is possible to have good water resistant property if fully optimized.
- ItemMicrostructural characteristics and wear behaviour of HVAF sprayed Ni-SiC composite coatings(Elsevier, 2025-03-10) Owoseni, Tunji Adetayo; Baiamonte, Lidia; Dumm, Timothy; Björklund, Stefan; Joshi, ShrikantHigh-velocity air fuel (HVAF)-sprayed SiC coatings have been investigated as a potential approach to address challenges associated with their successful application through thermal spraying, since SiC can potentially serve as a sustainable replacement for WC in tribological hard coatings. Ni-P capped SiC feedstock was processed to fabricate composite coatings using HVAF, which is a relatively recent versatile and cost-effective spray technique. Three coatings, Ni-SiC-1, Ni-SiC-2, and Ni-SiC-3 were sprayed using various parameters to investigate the relationship between the processing conditions, microstructure, and wear performance. The extent of SiC retained in each of the coatings, albeit fragmented, was determined to be ∼25 % for each of the three coatings compared to the 54 wt % SiC presence in the feedstock. However, despite the similarity in the quantity of SiC retained in the respective coatings, two of the coatings (Ni-SiC-1 and Ni-SiC-2) showed mixed amorphous and crystalline phases, whereas the Ni-SiC-3 coating was fully crystalline. The microindentation hardness of the coatings in the as-sprayed and annealed forms was noted to be in the range of 800–850 HV0.1. The specific wear rates for the respective coatings in the as-sprayed and annealed forms were found to be promising but of the same order of magnitude, revealing no significant role of annealing on their tribological behaviour. The results establish that it is possible to process a suitably designed SiC feedstock using HVAF to realize a sustainable wear-resistant coating.
- ItemOn the hydrodynamics of macroporous structures: Experimental, CFD and artificial neural network analysis(Elsevier, 2023-11-15) Otaru, A. J.; Alhulaybi, Z. A.; Owoseni, Tunji AdetayoPorous metallic structures play a critical role in mass and heat transfer processes due to their high surface areas, fixed porosity, and high stiffness – so understanding their fluid flow behaviour is crucial in designing materials that perform efficiently in mass and heat transfer. In view of this, a multi-disciplinary approach is employed to study the hydrodynamics of aluminium foams produced by a liquid melt infiltration technique using experimental, computational fluid dynamics (CFD) modelling and simulation, as well as artificial neural network (ANN) machine learning backpropagation. X-ray computed tomography datasets were used to characterize pore-structure-related properties of replicated materials, followed by three-dimensional advanced imaging of workable representative volume elements. Hydraulic flow information was acquired for the porous matrices using the constant-head permeameter technique. Experiments showed the permeability and Forchheimer coefficient dependence on pore-structure-related properties for fluid-flowing within the pre-Forchheimer and fully developed Forchheimer regimes. Flow permeability of 8.479 × 10−09m2 was highest in the material with the widest mean pore openings (0.212 mm) and lowest (1.291 × 10−09m2) in the material with the narrowest mean pore openings (0.106 mm). Conversely, Forchheimer coefficients were higher for materials with lower porosities and lower for materials with higher porosities. CFD calculations accurately predicted the fluid properties of metallic foams, as well as the influence of intrinsic foam properties on permeability and the Forchheimer coefficient. The ANN model framework was also able to provide valuable information about the hydrodynamics of these materials. Convolution and non-linearity of the ANN model were improved by adding supplementary neurons to the hidden layers allowing deviations within 0.3 and 9.0 percent to be attained.
- ItemSmall Scale Biochar Production Technologies: A Review(Scholarlink Research Institute, 2010-12-01) Odesola, Isaac F.; Owoseni, Tunji AdetayoThis paper is set to review the available small scale biochar production technologies. Biochar production technologies are a few of the green technologies that seek to rid the environment of green house gases (GHG). The products of this technology are biochar and biofuels (oil and syngas). Variant methods of this small scale production are known. The use of single (metal) container to two barrels is common, while some units are built of ceramic materials like fired brick. However, there is no published work stating the production of biochar in Nigeria, as at the time of this compilation.