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Item A synergetic effect of ternary refractory nitride reinforcements on densification, mechanical, tribological and thermal stability characteristics of spark plasma sintering-developed Ti6Al4V matrix composites.(Elsevier, 2024-05-17)This paper reports the possibility of developing advanced Ti6Al4V matrix composites (TMCs) with enhanced mechanical properties and highly improved resistance to wear and thermal degradation for structural and high temperature aerospace applications. The synergetic effect of different weight compositions (1, 1.5 and 2 wt%) of ternary reinforcements consisting of h-BN, TiN and AlN nanoparticles on the characteristics of the microstructure, phase constitution, densification, mechanical, tribological and thermal stability of Ti6Al4V matrix composites developed by spark plasma sintering (SPS) is investigated. The unreinforced Ti6Al4V exhibited a two phase microstructure made up of α/β phases, however the simultaneous reinforcements resulted in notable microstructural changes and emergence of nitride-rich secondary phases. The relative densities of the composites decrease with increasing reinforcement addition, whereas the nanohardness and elastic modulus values of the composites continue to improve with increasing reinforcement from 1 wt% (28.319 ± 0.525 GPa and 219.43 ±6.77 GPa) to 2 wt% (55.642 ± 0.693 GPa and 314.59 ± 7.58 GPa) compared to the unreinforced Ti6Al4V (5.838 ± 0.323 GPa and 115.07 ± 3.63 GPa). The unreinforced alloy yields higher average COF values, while the composites at equivalent applied normal loads yield lower average COF values. Thus, in comparison to the unreinforced alloy, the produced composites exhibit considerably lower specific wear rates (with increasing applied normal load). Based on thermogravimetric analysis, the oxidized composite reinforced with 1 wt% of ternary reinforcements exhibits the highest thermal stability in the high-temperature oxidizing environment, as evidenced by its greatest resistance to oxidation and its smallest weight gain of 1.55%.Item Thermal performance of vapour compression refrigeration system using bimetallic strontium hexaluminate nanorefrigerants.(Nigerian Journal of Technological Development, 2024-09-10)Nanoparticles are added to standard compressor lubricants to improve performance and reduce the energy consumption of vapour compression refrigeration systems (VCRS). This work evaluated the compatibility, viability, and utility of a bimetallic oxide strontium hexaluminate (SrAl12O19) nano-lubricant with nominal sizes of 20–40 nm by characterising and evaluating its thermophysical properties while assessing its effect on the performance and energy consumption of existing, unmodified VCRS. Eco-friendly R600a were used as the system's refrigerant and the performance, energy consumption, and energy efficiency of VCRS were investigated by altering the concentration of SrAl12O19 (1%–20%) in the compressor lubricant. The results showed that as the temperature increases, the viscosities significantly decreased and increased as the concentration of nanoparticles is increased. In contrast, the density and acidity of the nanolubricant increased as the volume concentration of nanoparticles increased. The addition of nanoparticles into the compressor oil enhanced the performance of the VCRS performance and reduced the energy required to operate the system; however, these performance metrics decreased as the concentration of nanoparticles increased further. When the concentration of nanoparticles increased, exergy efficiency reached the maximum at 5% volume concentration.Item Surface protection of carbon steel with ZrO2 composite induced zinc based electrolytic cell via electrodeposition technique.(Purpose-LED Publishing, 2019-01-01)The effect of Zirconium dioxide (ZrO2) as additive to Zn-MgO electrolytic chemical bath coating by co-deposition on carbon steel was investigated. Weight loss was conducted on the electrodeposited mild steel and it was inspected. The anti corrosion properties were assessed by linear polarization procedure in 1 mole of HCl medium. From the results gotten, all deposited coatings displayed significant improvement. An amazing improvement was accomplished in every one of the coatings as against the as-received sample. Zn-MgO-ZrO2 (0.8V) with the best performing coating showing an upgrade indicates enhanced anti-wear and friction qualities displaying wear resistance improvement.Item Design and biological evaluation of delivery systems containing bisphosphonates.(MDPI, 2016-11-30)Bisphosphonates have found application in the treatment of reoccurrence of bone diseases, breast cancer, etc. They have also been found to exhibit antimicrobial, anticancer and antimalarial activities. However, they suffer from pharmacological deficiencies such as toxicity, poor bioavailability and low intestinal adsorption. These shortcomings have resulted in several researchers developing delivery systems that can enhance their overall therapeutic effectiveness. This review provides a detailed overview of the published studies on delivery systems designed for the delivery of bisphosphonates and the corresponding in vitro/in vivo results.Item Effect of some process variables on zinc coated low carbon steel substrates.(Academic Journals, 2011-06-03)This work investigates the effect of some essential plating variable of zinc electro-deposition on low carbon steel substrates. The variation of plating parameter, the depth of immersion, distance between the anode and the cathode on voltage, plating time and coating thickness was considered. The steel substrates were immersed into solution of zinc electroplating bath for varying voltage between 0.5 and 1.0 V. It was discovered that the sample plated at 0.8 V for 20 min gave the best plating properties and it was also observed that increase in applied voltage, plating time, depth of immersion and decrease in distance of the object (cathode) from the anode increases weight gained. Microstructural studies with SEM/OPM however, revealed fine grained deposit of the deposited zinc and the inclusion of addition agent.
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