The purposes of the research were to create and find out the efficiency validation of computer assisted instruction focused on the Plastic Injection Adjusting Machine and Injection Molding Maintenance for the standard 90/90 and to analyze the students’ learning achievement after using computer assisted instruction. The samples were 20 first year diploma tool & die students at Rajamangala Institute of Technology North Bangkok Campus. The students pretested and then studied by using the computer assisted instruction focus on the plastic Injection Adjusting Machine and Injection Molding Maintenance. Finally the students post tested. After that the data was calculated to find out the computer assisted instruction efficiency and analyzed the students’ learning achievement after studying. The result revealed that the computer assisted instruction efficiency was reached the standard 90/90 and the students’ learning achievement increased significantly at 0.05.

This research aims to evaluate the effectiveness and limitations of the Road Safety Audit in Thailand. The evaluations would be used as a guideline to set Road Safety Audit policy for transport authorities in order to enhance the traffic safety in the construction area. In the study the construction project route 318 Trat-Had Lek part2 (Section1) Sta.1+900.00 to 20+000.00 (total distance of 18.100 kilometer) was selected as a case study. The accident statistics occurred before the construction and during the construction were compared to analyze the effectiveness of the Road Safety Audit used in the project. The result of the study shows that the main cause of the accident are traffic management traffic sign and marking as well as pavement surface. Therefore the researchers have provided some recommendations against the accident causes. Finally the operations of the contractors according to the recommendations were monthly summarized to measure the effectiveness of the recommendations.

Comparing the shrinkage values of HDPE 2 – 4 % that limited from manufacturer are as the following: 1. Comparing the shrinkage of 60 X 60 mm. specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 1.1 Comparing the shrinkage of the specimen with 2 mm. thick The result showed that the shrinkage between at the point nearby the entrance is different from at the point further from the entrance and it is also different from the limited value from the manufacturer. 2. Comparing the shrinkage of 12.7 X 27 mm. specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 2.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among the point nearby the entrance the point further from the entrance and the limited value from the manufacturer. 3. Comparing the shrinkage of 100 mm. round specimen The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 3.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among the point nearby the entrance the point further from the entrance and the limited value from the manufacturer. Comparing the shrinkage values of PET 0.2 - 0.4% that limited from manufacturer are as the following: 1. Comparing the shrinkage of 60 X 60 mm. specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but it is not different from the limited value from the manufacturer. 1.2 Comparing the shrinkage of the specimen with 2 mm. thick The finding revealed that the shrinkage value between the point nearby the entrance and the point further from the entrance are different but the same as the limitation from the manufacturer. 2. Comparing the shrinkage of 12.7 X 27 mm. specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but the same as the limited value from the manufacturer. 2.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The result showed that there aren’t any shrinkage differences among follow the injection across the injection and the limited value from the manufacturer. 3. Comparing the shrinkage of 100 mm. round specimen The finding revealed that the shrinkage value of the follow injection is different from the across injection but it is not different from the limited value from the manufacturer. 3.1 Comparing the shrinkage of the specimen with 3.2 mm. thick The finding revealed that the shrinkage value of the follow injection the across injection and the limited value from the manufacturer are the same. Both comparing HDPE and PET have statistical significance at 0.05