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Spur Spur Spur Spur gears gears gears gears are the most commonly used gears for mechanical power transmissio are the most commonly used gears for mechanical power transmissio are the most commonly used gears for mechanical power transmissio are the most commonly used gears for mechanical power transmissio in in in involute volute volute volute spur gear involves specification of the cutting speed for t spur gear involves specification of the cutting speed for t spur gear involves specification of the cutting speed for t spur gear involves specification of the cutting speed for t cutter. cutter. cutter. cutter. The speed and feed The speed and feed The speed and feed The speed and feedrate rate rate rate selection for such cutting selection for such cutting selection for such cutting selection for such cutting machining exercise, which indirectly machining exercise, which indirectly machining exercise, which indirectly machining exercise, which indirectly also determines the cost of producing the gears. This paper present also determines the cost of producing the gears. This paper present also determines the cost of producing the gears. This paper present also determines the cost of producing the gears. This paper present carried carried carried carried out in establishing a multiple out in establishing a multiple out in establishing a multiple out in establishing a multiple linear regression model linear regression model linear regression model linear regression model in in in involute spur gear tooth at varying speeds and feed volute spur gear tooth at varying speeds and feed volute spur gear tooth at varying speeds and feed volute spur gear tooth at varying speeds and feed with pressure angle 20 with pressure angle 20 with pressure angle 20 with pressure angle 20 0 0

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It is widely known that quarry industry has great importance in developing countries, such as Nigeria. There is paucity of information regarding effects of noise experienced by quarry workers during their working time. Therefore, this study investigated the influence of age of workers, years of exposure of workers and noise level of the machine used in quarry on hearing threshold. A factorial design of experiment was employed for the investigation. Two hundred and four quarry workers volunteered for this study from four quarries in South western Nigeria. Emitted noise, which quarry workers were exposed to during machinery operation, was measured with a digital sound level meter and workers hearing threshold was measured in an audiogram sound proofing testing booth at standard conditions. Predicted models were established from experimental design to determine main and interactions effects towards the response (hearing threshold). These were statistically analysed using analysis of variance (ANOVA). All terms of the models were significant at p<0.05. The best fitted model was at 4kHz (R2 = 0.639, p<0.05). The magnitudes of the main effect of the factors are in ascending order of noise level >years of exposure>age. The analysis of the experimental response indicated that there is no interaction of any factors on the hearing threshold. It can be concluded that age, years of exposure and noise level have main effects at various capacities at different frequency to predict the hearing threshold of the quarry workers. This work determined the factors and the predicted model to spell out safe hearing threshold of quarry workers that fitted for the job at a particular noisy workstation as well as ensuring comfortable, safe and effective workstation design.

Air conditioning system is an indispensable part of buildings today. The cost of this system increases with the rise in energy consumption which poses a challenge as well as air distribution in large auditoria. Analysis of results can also be daunting when designing this system. The study focuses on designing an air conditioning system in a large auditorium, applying Computational Fluid Dynamics (CFD) and visualizing the result in a Virtual Reality (VR) environment. The 3-dimensional model of the 520-capacity Technology Lecture Theatre, University of Ibadan, Nigeria was drawn with Autodesk Revit and modified into the geometry applicable for Displacement Ventilation (DV) and Mixed Ventilation (MV) for ease of numerical analysis with ANSYS Fluent. The building model and simulation results were then imported into Unity software for visualization in VR. The DV achieved better thermal comfort and air distribution in the computer simulation. At a supply temperature of 292.15 K, the DV system was able to keep the auditorium temperature at about 296.50 K, while the MV system at a supply temperature of 289.15 K was only able to maintain the temperature at 295.40 K. The temperature profile showed that the lower region where the students were seated was colder in DV compared to MV by at least 3 K. The results were also observed from a convenient position in VR. This study, with the aid of CFD and VR, was able to establish that displacement ventilation design has better air flow, lower energy consumption and is efficient for an air conditioning system in a large auditorium.