No abstract

Die castings are prone to contain considerable porosities due to the entrapment of air or gases in the molten metal during mold filling. Reducing the die filling velocity is effective for reducing the entrapment, but it increases surface defects, such as surface folds and cold shut on die castings.In this research, the solidification behavior of molten metal during mold filling was investigated by developing a highly sensitive thermosensor with a response time of 0.015 s that can correctly measure the temperature of flowing molten metal. The criterion for the formation of surface defects was further examined based on the solidification behavior of molten metal during mold filling.It was found that the type of surface defects varies with the solidification manner of aluminum alloys. Surface fold defects occur on die castings made of JIS AD12.1 alloy with skin-formation type solidification. The occurrence of surface folds can be predicted by the thickness of the solidified layer of the molten metal from the surface of cavity. The critical thickness for the formation of surface folds increases with increasing casting pressure. On the other hand, cold shut defects occur on die castings made of JIS AC4C alloy with mushy-formation type solidification. The molten metal temperature drops toward the tip of the molten metal flow. The occurrence of cold shut defects can be estimated by the temperature of this molten metal flow tip at the time this flow converges with other flows.

The present study examined the effect of cooperative games in physical education (PE) and sports classes on the stress coping and problem-solving skills. The fifteen elementary schools in the volcano disaster area assigned to the intervention and two control groups. The intervention group received PE and sports lessons with cooperative games while the control groups completed PE and sports lessons consistent with each school's existing curriculum over 28 weeks. The stress coping and problem-solving skills scales, previously developed for use with students, was implemented before and after the program. Two-and one-way analysis of variance and paired sample t-tests used to compare the three groups, and a Pearson correlation analysis used to examine the relationship between skills at pre-and post-test. The analysis showed a significant increase in stress coping and problem-solving skills in the intervention group over two control groups. The PE and sports lessons with cooperative games could effectively promote both students' stress coping and problem-solving skills.

Previous research has discussed the interaction of hand preference, eye dominance, and sport performance. In this study, the relation of eye dominance with performance and subjective ratings in golf putting was investigated. 47 right-handed Japanese students from a college of physical education putted 10 balls to a drawn circle 3 m away, each under right-handed and left-handed stance conditions. Putting performance was measured by the number of successful putts. After putting in each condition, they rated subjective visibility and feelings of hitting. Analyses indicated that right-eyed subjects had significantly better performance using the right-handed stance than the left-handed stance, whereas left-eyed subjects showed the opposite. Most subjective ratings were more positive with right-handed stance for both right-eyed and left-eyed subjects. These findings suggest that eye dominance could have some influence on putting performance of Japanese novice golfers.

This study investigated the influences of sport experiences on social skills among Chinese college students in physical education (PE) classes. First, we tested the reliability and validity of the Chinese version of the Experience Scale in University Physical Education Classes (ESUPEC) for examining Chinese college students' sport experiences in PE classes. Students (n = 366, 194 males, 172 females, mean age = 18.6 years) from two universities in China completed a survey using the Chinese version of ESUPEC. Results of factor analyses and reliability analyses indicated that the structure of the scale was consistent with the original version of ESUPEC, and the reliability and validity of the scale were reasonable well. Then, we administered the Chinese version of ESUPEC and the 11 item of Social Skills Inventory (11-SSI) to 302 freshmen (157 males, 145 females) to examine their sport experiences and social skills in PE classes. Results of correlation analysis and regression analysis revealed that male students' sport experiences that involved challenge and female students' sport experiences that involved self-disclosure had a positive influence on their nonverbal skills; female students' sport experiences that involved enjoyment had a positive influence on their verbal skills. The study contributes to literature on exploring how college students' social skills can be developed through learning in PE. The work of the study made a step to provide educators with methods for effective development and efficient implementation of models and programs in PE classes.