Browsing by Author "OGEDENGBE, T.S."
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Item Comparative Analysis of Machining Stainless Steel using Soluble and Vegetable oils as Cutting Fluids(International Journal of Engineering Materials and Manufacture, 2019-03-01) OGEDENGBE, T.S.; AWE, Peter; Joseph, Ojotu IjiwoIn this study, the performance of groundnut oil as an alternate cutting fluid was compared with that of soluble oil during machining of stainless steel. The temperature at the cutting zone, surface roughness and the chip formation were monitored under the two cutting conditions (soluble oil and vegetable oil). The machining parameters used were cutting speed (75 – 135 rev/min), feed rate (0.01 – 0.05 mm3/mm) and depth of cut (0.01 – 0.08 mm). The experiment was designed using Taguchi orthogonal array of Minitab 18 which generated a 9 run machining parameter mix for the experimentation. The Physiochemical properties of the various fluids were also analyzed to determine the properties and constituent elements of the cutting fluids. The actual machining of the stainless steel bar was done using a Colchester mastiff lathe machine. Results show that feed rate and cutting speed had the most significant effect on surface roughness during machining of stainless steel both with groundnut oil and soluble oil. Soluble oil was a better coolant but poorer in lubrication as vegetable oil reduced surface roughness more when used. Surface roughness value improved from 9.21μm during machining with soluble oil to 3.84μm during machining with groundnut oil which represented a 58.3% improvement. Hence, vegetable oil is therefore recommended as good alternative cutting fluid to soluble oil during machining of stainless steel.Item INVESTIGATING THE PERFORMANCE OF R134A DOMESTIC REFRIGERATOR RETROFITTED WITH R290 (PROPANE) AND R600A (ISO-BUTANE) REFRIGERANTS IN THREE DIFFERENT SIZE OF CAPILLARY TUBE IN A REFRIGERATING SYSTEM.(Proceedings of the 2018 International Conference on STEM: A driving force for sustainable development tagged COLENG 2018, Federal University of Agriculture, Abeokuta, May 14-17, 2018, 2018-05) YUSSOUFF, Abiodun .A.; OWOEYE, S.O; YUSSOUFF, Abidemi .O.; OGEDENGBE, T.S.; SAHEED, Rasheed O.In Nigeria, most of the vapour compression based refrigeration systems continue to run on halogenated refrigerants due to its excellent thermodynamic and thermo-physical properties. However, the halogenated refrigerants have adverse environmental impacts such as ozone depletion potential and global warming potential. Hence, it is necessary to search for alternatives to halogenated refrigerants. R290 (Propane) and R600a (Iso-butane) are two environmentally friendly refrigerants while R134a (Hydrofluorocarbon) is a common halogenated refrigerant. This study evaluated the performance of R290 and R600a refrigerants retrofitted into an R134a refrigerator. The temperatures at the four units (compressor, condenser, dryer/filter and evaporator) of the refrigerator were taken at different ambient temperature ranging from 15oC to 33oC. Also, pressures at both the inlet and outlet of the compressor were taken using the run time of 8 hours. Propane (R290) and iso-butane (R600a) were both charged in separately into the domestic refrigerator after R134a has been discharged, thoroughly flushed and evacuated. All tests were repeated for R290 and R600a. The data obtained was used to compute the following system performance parameters: refrigeration capacity, compressor power input, Coefficient of Performance (COP) and compression ratio. Average COP, average refrigeration capacities (kW), average compressor power (kW) and compression ratio of 0.499, 0.92, 0.188; 0.55, 0.49, 0.38; 1.82, 1.63, 1.25 and 6.02, 6.38, 6.67 were obtained using R600a, R290 and R134a respectively. The standard deviation for average COP, average refrigeration capacity(kW), average compressor power and average pressure ratio of 0.052,0.218,0.04; 0.023,0.072,0.065; 0.92,0.62,0.43 and 0.17, 0.17, 0.14 were obtained. Overall assessment showed that R600a and R290 have a relatively low compression ratio and better COP. The COP and compression ratio were used to quantify the performance of a refrigeration cycle. Low compression ratio increased refrigeration efficiency and decreased compressor energy consumption which indicated better system performance and reliability providing longer life to the domestic refrigerator. The average refrigeration capacity and compressor power obtained during test using R600a and R290 were higher than those of R134a indicating an effective cooling power of R600a and R290 over R134aItem Sustainable Machining Processes through Optimization of Process Parameters(International Journal of Engineering Materials and Manufacture, 2019-03-01) OGEDENGBE, T.S.Machining processes are a vital part of manufacturing activities in major industries that contributes to the growth of the economy. They mostly require high amount of electrical energy to power the various support modules installed on machine tools. Carrying out machining activities with a view to reducing energy consumption will therefore result in a lowered cost of production for manufactured products. Previous studies on some energy-saving methods adopted by researchers and the limitations faced in the reduction of energy consumption have been discussed. In this work, the effect of process parameters in the conservation of energy during machining processes was experimented. Minitab 16 was used to design the experiment and a 9-run orthogonal array was generated. The machining parameters were cutting speed (80 – 120 m/min), feed (0.05 – 0.07 mm/rev) and depth of cut (0.1 – 0.3 mm). A high carbon steel bar was machined using high speed steel tool and the energy consumed during the machining process was measured. Energy (28.67 kw/hr) was consumed during machining at 0.005 mm/rev and 0.3 m. Energy (12.83 kw/hr) was consumed while machining at 0.07 mm/rev and 0.1 m. The energy consumed changed with machining parameters. These results showed that much energy could be saved by optimizing parameters before machining.