Abstract. The purpose of this study was to investigate the vibration characteristics of both front and back vented brake discs with physically different shapes. In accordance with theory, the heat transfer rates of the two types of brake disc were different and played an important role in deformation during usage. A dynamometer was used as an engineering tool for the experimental work, with boundary conditions according to the Japanese Automobile Standard JASO C406. One degree of freedom (DOF) acceleration signals on the brake calipers were analysed. Results indicated that the back vented brake disc reduced the vibration by up to 43.5% compared to the front vented brake disc with braking temperature at 200C, initial braking speed 50 km/h and hydraulic pressure of 4 MPa. Hydraulic pressure at 4 MPa generated the maximum vibration. Initial braking speed and braking temperature were also important factors.

This study aimed to analyze the difference in operation of the vapor compression refrigeration (VCR) system with vortex tube cooling. By using varied loads, experiments were conducted on the evaporator section of a vapor compression refrigeration system. In an attempt to improve the use of subcooling for the refrigeration, the effect of subcooling of refrigerant by vortex tube cooling was likewise examined. The test conditions included various loads (25%, 50%, 75% and 100%) and cold mass fractions (25%, 50% and 75%). This research described coefficient of performance (COP) as one of the significant parameters, in addition to heat rejection and refrigerating effect. The ideal efficiency appeared to be with the cold mass fraction of 25% and load of 100%, as identified by the results. Consequently, the COP could be enhanced by 5.16% along with an approximately 4.36% decline in average power use. Improved guidelines for vapor compression refrigeration systems to enhance the operation of the system are an expected benefit of this study.