Mechanical Engineering

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Mechanical Engineering

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Start date: 2020End date: 2021

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    EFFECTS OF OXIDIZED SUCROSE CROSS-LINKED CASSAVA STARCH FILM ON THE PHOTOVOLTAIC PROPERTIES OF PEROVSKITE SOLAR CELLS
    (The Nigerian Institution of Mechanical Engineers (A Division of Nigerian Society of Engineers), 2021-09) J. Y. Jiya; J. S. Enaburekhan; M. T. Jimoh; E. C. Egwim; I. A. Joseph
    Despite rapid progress in the perovskite solar cell efficiency, there have been concerns about issues which could affect the measurement accuracy and/or practical applications of these devices, amongst which are stability, scaling up (large area devices), and possible environmental effects related to the use of lead-based active material. Based on the findings from previous studies, an optimized biodegradable oxidized sucrose cross-linked cassava starch film layer with zirconium oxide is introduced as a desiccant and buffer against damp heat and thermal recycling. This modified photovoltaic device is capable of resisting ingress of moisture at elevated temperatures, withstanding temperature cycling without delamination, and as such, enables efficient and stable operation. The layers in the PSC were modified by replacing the conventional metallic counter electrode with a low-cost carbon counter electrode. The PSC device with the control architecture underwent a more rapid degradation, particularly within the first 288 hours though with a higher PCE than the modified device. However, in contrast, the PSC device with the buffer layer only degraded a small amount. The best device maintained 95% of its initial efficiency after exposure for 550 hours.
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    A Fundamental Review of Trends in Perovskite Solar Cells Based on Introduction of Buffer Layers to Enhance Stability
    (JOURNAL OF SCIENCE TECHNOLOGY AND EDUCATION, 2020) J. Y. Jiya; J. S. Enaburekhan; M. T. Jimoh; E. C. Egwim
    Perovskite solar cells (PSCs), as photo-electric conversion devices, exhibit adequate power conversion efficiency (PCE) and low processing cost and have thus become one of the most promising devices to replace conventional silicon-based solar cells thereby addressing current prevailing energy issues. Despite rapid progress in the perovskite solar cell efficiency, there have been concerns about issues which could affect the measurement accuracy and/or practical applications of these devices, amongst which are stability, scaling up (large area devices), and possible environmental effects related to the use of lead-based active material. Current PSCs use nonbiodegradable petroleum-based polymer substrates, discarding of which will aggravate environmental pollution. In this study, a review of the fundamentals and progress in the perovskite solar cell (PSC) is discussed. The processing cost of metal electrode deposition in PSC is very costly, hence, the replacement of the metal electrode by some other low-cost counter electrode is discussed.
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    TIMISATION OF PLASMA ARC CUTTING PROCESS OF AISI 304 STAINLESS STEEL USING DESIGN OF EXPERIMENT
    (The Nigerian Institution of Mechanical Engineers (A Division of Nigerian Society The Nigerian Institution of Mechanical Engineers (A Division of Nigerian Society), 2021) A. O. Nasir; R. O. Medupin; J. Y. Jiya; K. Okon; C. C. Ozoh; I. S. Sule; S. A. Lawal
    Owing to its corrosion resistance capability, stainless steel stands out as a material of choice in food processing and other allied industries. However, cutting, during manufacturing activities, poses enormous challenge with regular thermal cutting processes. This study has optimized plasma arc cutting process of AISI 304 stainless steel using a full factorial experimental design. The input process parameters were Cutting Speed (CS), Cutting Current (CC) and Gas Pressure (GP) while the response variables were Material Removal Rate (MRR) and surface roughness. Analysis of Variance (ANOVA) was performed in order to identify the effect of each input process parameters on the response variables. ANOVA revealed that whereas CS made 31.1% contribution to surface roughness of the stainless steel, CC and GP only contributed as much as 31.7% and 28.2% respectively. CC had the most significant effect of 36.07% on MRR followed by GP and CS with 28.02% and 27.11% respectively. While the optimal cutting conditions for surface roughness were found to be 4000 mm/m for CS, 80 A for CC and 6 bar for GP, the optimal values for MRR were 4000 mm/m, 60 A and 6 bar for SC, CC and GP respectively. It can, therefore, be concluded that increase in cutting current favours increased material removal rate during plasma arc cutting processes of AISI 304 stainless steel.