Properties of melon seed and beniseed oils which are considered as "environmentally" friendly oils were investigated and the performance evaluation of the formulated beniseed and melon seed oilbased cutting fluids were carried out. American Iron and Steel Institute (AISI) 304L alloy steel was used as workpiece and tungsten carbide as cutting tool, while commercial mineral oil-based cutting fluid was used as a control experiment. The viscosities of the melon seed oil and beniseed oil-based cutting fluids were 1.53 mm 2/s and 0.86mm 2/ s, while their pH values were 8.2 and 8.7 respectively. The optimal multi-response turning parameters was achieved using cutting speed of 159 rev/min (level 3), feed rate of 0.9 mm/rev (level 3), depth of cut of 1 mm (level 2) and type of cutting fluid of 1.53mm/s (level 3). The ANOVA results show that feed rate has the most significant effect on the surface roughness (92.93%) and cutting temperature (27.51%).
Kaolin and ball clay samples from four states in Nigeria were examined with the aim of determining their chemical composition as well as testing for their suitability as refractory materials for furnaces lining applications. Three kaolin samples were taken from Ikpeshi in Edo, Kasadi in Kebbi and Alaasan in Osun state, while the ball clay sample used as the binder was taken from Badeggi in Niger state. The kaolin samples were tested and beneficiated in other to improve on their alumina contents after which they were characterized and produced as a refractory brick by mixing each kaolin sample with the ball clay in 70:30 ratio. They were then tested comprehensively for the following refractory properties such as: firing shrinkage, apparent porosity, bulk density, cold crushing strength, thermal shock resistance, refractory under load (RUL), thermal expansion, thermal conductivity, X-ray diffraction and scanning electron microscope.The results were compared with standard refractory properties for fireclay bricks. The values obtained from the three clay samples (A, B, C) which are from Ikpeshi in Edo, Kasadi in Kebbi and Alaasan in Osun state respectively were within the recommended values for fireclay bricks, most especially sample C which has a refractoriness under load (RUL) of 1348 O C which is the temperature at which the bricks will collapse under a constant load of 0.2N/mm 2 . This compared favourably with the RUL of other countries in the world.
Cutting fluids play a major role in machine operations, life of tools, workpiece quality and overall high productivity which are considered as potential input for minimal tool wear, minimal surface roughness and better machining finished product owing to the ability to prevent overheating of the workpiece and cutting tool. In this paper, the challenge of environmental biodegradability, tool wear and workpiece surface roughness prompt the need to evaluate and compare the performance of Jatropha oil based cutting fluid (JBCF) with mineral oil based cutting fluid (MBCF) during turning with AISI 304 Alloy steel which are presented. Test were conducted on the Physiochemical property, fatty acid composition (FAC), cutting fluids formulation of oil ratio to water ratio in proportion of 1:9, turning operation and response surface methodology (RSM) design of experiment were carried out and used respectively. Results from FAC indicated that jatropha seed oil (JSO) has an approximately 21.6% saturated fat with the main contributors being 14.2% palmitic acid. The physiochemical property results show pH value 8.36, Viscosity 0.52 mm2/s, resistant to corrosion, good stability and a milky colouration. The S/N ratio for main effect plot for JBCF and MBCF stand at 1250 CS, 1.15 FR and 0.65 DOC; and 500 CS, 1.15 FR and 0.65 respectively with R-sq = 85.14% and R-sq(adj) = 71.76% for JBCF Ra and R-sq = 71.24% and R-sq(adj) = 56.35% for JBCF Tw, compared to R-sq = 84.44% R-sq(adj) = 70.43% is for MBCF Ra, and R-sq = 70.48% and R-sq(adj) = 55.92% for MBCF Tw. Conclusively, JBCF exhibit minimal surface roughness, minimal tool wear, minimal environmental biodegradability and overall better performance compare to MBCF which makes it more suitable for turning of AISI 304 Alloy steel and is in good agreement with previous work.
The influence of the refractory coating which is a mixture of silica flour and kaolin on the surface roughness of the plate castings produced using evaporative patterns had been considered in this work. The kaolin was used as a binder and ratio method was employed to form basis for the factorial design of experiment which led to nine runs of experiments. Methyl alcohol at 99% concentration was used as the carrier for the transfer of the coating to the surface of the patterns. Pouring temperature was observed as a process parameter alongside the mix ratios of the coating. Attempts were made to characterize the refractory coating by using two methods; differential thermal analysis (DTA) and X-ray diffraction. Attempt was also made to characterize the casting material. Gating system design was done for the plate casting to determine the correct proportions of the gating parameters in order to construct the gating system properly to avoid turbulence during pouring of liquid metal. A digital profilometer was used to take the measurements of the surface roughness. It was observed that the mix ratio 90% silica flour-10% kaolin produced the lowest value of the surface roughness of the plate castings and had the lowest material loss in the DTA test. The pouring temperature of 650 o C produced best casting.
In a two-stroke engine, the net quantity of air/fuel delivered to the cylinder is usually less than that demanded amount due to flow constraints, the nature of working fluid, port timings and pressure waves. Central to all these losses is the limited time for combustion relative to the intake ports' open down periods. This research utilises a manifold differential-pressure model to establish a loss of fresh-charge due to the supply time-lag and cycle-overlaps which are chiefly dependent on the ports' positions and engine speeds. Three different throttle angles and engine speeds were utilised to establish differential flow rates between the ports' opening and closing intervals. Test results show that at low intake pressure and engine speed, 12.5 ms is required to fulfil the engine demand with a maximum value of 16.5 g/s occurring at 4 ms. The corresponding supply is 5.5 g/s lagging by about 7.5 ms and resulting in a maximum loss of 13 g/s. At high speed with the same initial pressure, the maximum demand of 40 g/s occurs at 2.5 ms while the maximum supply of 32.5 g/s lags behind by 5 ms, resulting in a maximum loss of 22.5g/s. Thus, the differential pressure model is a useful tool for estimating the difference between the charge demanded and that supplied.
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