Universal joint damage occurred during the operation of a combat vehicle. Damage to the internal bushing and cracks of the rubber cover occurred, and a design change was promoted based on the cause analysis and improvement measures. The failure of the bushing is due to the occurrence of expansion due to fatigue load when the rotation proceeds in the presence of the assembly clearance of the cross joint. In addition, cracks in the rubber cover are caused by the deterioration of the intermetallic rubber surface. Through this failure mechanism analysis, severe durability factors were selected and accelerated durability tests were conducted. In this paper, the final limit life of universal joints can be evaluated through accelerated endurance tests. Furthermore, the endurance life of the product before the change and the endurance life of the product after the change are compared to prove the improvement effect through design changes.

This study was conducted on the properties of exhaust emissions of diesel oil and fish oil blended with diesel oils using a direct injection diesel engine at different loads, and on the conditions of carbon deposits of diesel oil and 40% blend oil in the combustion chamber after 20 hours operation at 1]2 load. The properties of exhaust emissions by fish oil blended with diesel oils showed no significant difference with diesel oil. However, soot emissions decreased, increasing the ratio of fish oil. Carbon deposits by fish oil blended with diesel oils were high level compared with diesel oil, which might be overcome by preheating of fuel oil and operating conditions.

This present study investigated the effects of goal setting methods on sit up performance in elementary school children. Subjects Were 80 pupils from the five grade in elementary school. they were randomly assigned to four conditions : specific goal setting(individual), specific goal-setting(group), nonspecific goal setting(individual), nonspecific goal-setting(group), they practiceed sit-up in class three time a week for weeks according to the experimental treatments. Two way ANOVA indicated that goal setting methods were appeared sigbigicant differences (p <0.05). In the camparison between these two groups, specific goal-stting group was higher than nonspecific goal-setting group in sit-up performance. A review of both laboratory and field studies of the effects of goals setting when performing a task that 90% of th studies specific and challenging goals lead to higer performance than non-specific goals. Goal setting is likely to improve Endurance performance when the goals are specific and sufficiently challenging.