IJET Vol. 9, Issue 2, June 2024
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Öğe Mechanical Performance Enhancement of AlkaliActivated Composites Using Synthetic Fibers with Metazeolite and Aluminum Sludge-Based Recycled Concrete Aggregates(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2024) Aygün, Beyza Fahriye; Uysal, Mücteba; Çingi, RamazanThis study examines the substantial enhancement in the performance of alkali-activated composites (AACs) produced from a distinctive combination of metazeolite (MZ) and slag (S), reinforced with synthetic fibers, and augmented with aluminum sludge (AS) and recycled concrete aggregate (RCA). The composites were subjected to activation through the use of a specific sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) blend in a 2:1 ratio, with an activator-to-binder ratio of 0.95. Through a process of experimentation, the research team identified an optimal mix by varying the molarities of sodium hydroxide (NaOH) between 8M and 14M and the ratios of metazeolite to slag between 25% and 100%. The aforementioned mixture, comprising 50% MZ and 50% S, was activated with 12M NaOH and enhanced with 30% aluminum sludge, exhibiting remarkable strength characteristics. Furthermore, the incorporation of synthetic fibres, including polyethylene (PEF), polyamide (PAF), and basalt fibers (BF), resulted in a notable enhancement of the material's performance. It is noteworthy that the addition of basalt fibers at a concentration of 0.5% resulted in a 7% increase in compressive strength and a 24% improvement in flexural strength. This pioneering research illuminates the transformative potential of MZ-S-based AACs, particularly when combined with AS and BF, paving the way for the development of sustainable construction materials that meet contemporary performance and environmental standards.Öğe Numerical Simulations of an Al2O3-Water Nanofluid-Based Linear Fresnel Solar Collector(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2024) John, Akpaduado; Oyekale, JosephThis study aims to numerically investigate the performance of Al2O3-water nanofluid as a heat transfer fluid (HTF) in a linear Fresnel solar receiver. Although a reasonable number of studies have investigated the thermal behaviors of different nanofluids as HTF in solar collectors, the focus has so far been on the parabolic trough collectors, with little or no research efforts available for the linear Fresnel collectors. ANSYS-fluent software was utilized for the simulation in this study, which converted the governing equations to algebraic forms based on the control-volume approach. The Nusselt number and wall temperature were used to characterize the thermal performance of the nanofluid, while the friction factor and eddy viscosity were considered to determine the flow features. The correlation equation proposed by Gnielinski was used to determine the Nusselt number, while the flow features were computed using the Darcy-Weisbach equation. Additionally, the thermal performance of the nanofluid was compared directly with that of pure water. Results showed that the nanofluid improved the thermal performance by about 6-19 % across the solar receiver length. Also, the Nusselt number increases non-uniformly across the length, with a significant rise towards the trailing edge of the nanofluid flow. Conversely, the pressure drop also increases with an increase in the solar receiver length, albeit uniformly. Designers should always factor into the design process to determine the optimum solar collector length when a nanofluid is considered as the HTF; to maximize heat transfer and minimize pressure drop and its attendant economic consequences.Öğe Development of a Cassava Grating Machine(İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2024) Aliemeke, Blessing Ngozi Goodluck; Iyore, Tommy AisosaDeveloping of a cassava grating machine is presented. This is a great boost in the development of local content and reduction of wastage in cassava produce in Africa. The use of internal combustion engine in powering the cassava grating machine makes the study unique as it goes a long way in eliminating the undue stress involved manual grating of cassava tubers. The developed machine is made up of components such as hopper, pulley belts, grating unit, internal combustion engine and shaft. Scientific formulae were employed to aid the design of the cassava grating machine. A detailed graphical modeling was done to serve as a guide for the fabrication of the machine. The developed grating machine had a volumetric capacity of hopper to be 50272000 mm3 . A power capacity of 1.715 KW was delivered to the solid shaft of 27.05 mm diameter to grate the peeled cassava tubers at a designed torque of 10.23 Nm.
