Nowadays the automotive parts industry greatly grows up in Thailand. Brake disc is one of products that play a role in safety area. As a result the various designs such as front and back-vented brake discs are occurred to improve the performance of usability. Consequently this study aims to develop the ability of braking dynamometer from 9.7 kg-m.1 kg-m. Moreover the influence of the front and the back-vented brake disc effecting on braking distance was investigated by single dynamometer referenced JASO C406 for testing condition. Therefore both of discs were operated under 100 200 and 300 °C of braking temperature and 2 4 and 6 MPa of line hydraulic pressure of braking. 2 to 1272 of moment of inertial From experimental works the test results reflected that the back-vented brake disc created braking distance shorter than front-vented brake disc ostensibly. Besides there are also diversity of factors as temperature pressure and initial speed of braking. Especially the higher temperature caused an increase of deceleration and a decrease of braking distance. Moreover the higher pressure produced a deduction of braking distance and a rise of deceleration. Finally the initial speed of braking was directly various the braking distances in same condition.

A disc brake is one of important auto parts for automotive industry which effected directly to life safety. The wear of brake rotor war affected to the brake efficiency. Lf the wear of rotor was discovered while operating the risk of accident shall be reduced. Therefore a study of disc wear affected to brake distance was the one of alternative for the brake efficiency testing. From this reason the aim of project is to test brake efficiency from the wear of brake rotor with the experiment conditions from JASO C 406 [1]. By the test conditions are focused on 3 cases of the wear: rotor little roughness rotor and abundant roughness rotor. The conditions of experiment consist of 100 200 และ 3000C on the rotor surface operating pressure 2 4 and 6 MPa initial speed before brake applied 50 and 80 km/hr. Based on the result of experiment was revealed that the braking distance deceleration and the brake ability with deceleration per unit of area. The result of experiment shown that the ordinary rotor at 6 MPa 300 0C and 50 km/hr. is given to the shortest of braking distance 69.7 m. Although the average of deceleration and the brake ability is take up on little roughness rotor. In case of the longest braking distance was occurred on the abundant roughness rotor. However from this study is discovered to the high temperature and the high pressure is significant to the braking distance shortened.

Braking system is the main of safety for motor vehicle. It uses to slow down or stop of vehicle movement. Normally braking system can not to adjustable in the recently. The brake efficiency depends up on to 3 factors by the perfection of brake equipment friction coefficient of road surface and the brake proportional. The factor of the perfection of brake equipment and friction coefficient of road surface can not be control. But in case of the brake proportional can be set up to suitable. In the other hand if the brake ratio is unsuitable the driver may be risk to danger from the loss of vehicle control. From this reason the aim of project is to study of the brake proportional affected to vehicle control. By the test condition consist of 2 cases: braking performance testing and vehicle stability testing. In case of braking performance testing is consider to deceleration braking distance and time of braking. For the vehicle stability testing is determined with yaw angle pitch angle sideslip angle and wheel lock up condition. However the bolt of testing is the road test and using the FMCSA standard for the testing guideline. The result of the braking performance testing shown the maximum deceleration was appeared on brake proportional 80:20. But the braking distance and time of braking are least because of the non-continuously of deceleration from the driver. Therefore the braking distance and time of braking depend on the continuously of deceleration. In term of vehicle stability testing discovered to the each of brake proportional are risk to danger for the driver especially on the 100:0 because of the value of sideslip angle is more than the critical point and the rear axle is lock up.

The study was aimed to 1) investigate influence of supervisors’ behavior leadership affecting working motivation of ground operation employees and organizational effective of a low cost airline and 2) study influence of supervisors’ behavior leadership on organizational effectiveness of a low cost airline. This research is descriptive collecting data through a questionnaire constructed from reviewing relevant documents. 88 samples responded to the five-scale the demographic questionnaire divided into 4 parts with the total of 84 items. The collected data were statistically analyzed by percentage mean ( X?) standard deviation (S.D.) multiple regression analysis multiple linear regression and Pearson Correlation Coefficients (Pearson Correlation Coefficients) The results showed that the hypothesis test on the influence of supervisors’ behavior leadership affecting working motivation of ground operation employees and organizational effective of a low cost airline yielding (1) the correlation coefficients between supervisors’ behavior leadership and employees’ motivation were positively correlated at the .05; (2) he correlation coefficients between supervisors’ behavior leadership and organizational effectiveness were statistically significant; and (3) the supervisors’ behavior leadership affecting employees’ working motivation and organizational effectiveness of a low cost airline at .05 level of significance (R = .712) and (R = .598).

Freight is major source of income of the State Railway of Thailand (SRT); which had revenues of one billion baht a year. The development of freight by rail system to be fart punctual and safe is important. Knuckle pin serves tension and shear stress in pulling Rolling Stock. Strength testing of Knuckle pin must be done by technical and engineering knowledge. SRT has 6000 Rolling Stocks; that means 6000 Knuckle Pin has been used and it is likely to increase due to the construction of the Double Track Project and the purchase of new Rolling Stocks. The efficient Knuckle Pin prolongs lifespan and SRT would have benefit on saving cost of maintenance and increase safety in the transportation of goods. This research is aimed at creating the understanding about the quality of the Knuckle Pin modeled Nat Mall. The pin would be test by Standard Test Methods for Tension Testing of Metallic Materialsand the Standard Test Method for Analysis of Carbon and Low-Alloy Steel by Spark Atomic Emission Spectrometry and Hardness Testing Machine and Microstructureto determine the cause of pin’s damage. This study will contribute the standardization of the quality of the Knuckle Pin which is used in Rolling Stocks of SRT.