The objective of this research is to study the development of eco cars using power-cutting mechanism technique of Transmission System. Two eco cars had been studied. The first car was conducted with the aim of developing transmission system and clutch system by changing from gear drive transmission system and chain drive mechanical clutch to belt and pulley transmission system by new designing the belt and pulley transmission system to have propeller shaft as the device to transmit power from the right to the left side with bearings to help reduce friction. Pulley system and clutch lever were installed in which the newly built clutch can be controlled by driver. The new model of transmission system is weight 0.7 kg which is lighter than the previous weight of 0.8 kg. Based on the first testing by participating in the 22nd Honda Eco Mileage Challenge at Chang International Circuit it was found that the system with belt tension at 1 kN resulted in good performance of transmission system and clutch system with fuel efficiency value at 626.157 km/L. After that the belt tension was adjusted and set up at 1.1 kN for 3 tests at Solar Track Thailand and it was found that the maximum fuel efficiency value was 1061.18 km/L at the speed of 34 km/hr. The second car was improved in transmission system suspension system steering system and also engine. The first trial was experimented on the 22nd racing event at the Chang International Circuit where this fuel efficient prototype car could run at 18 km. The result showed that it could have good mileage which was 275 km/L. After improvement the car was tested again for three times at the Solar Track Thailand circuit where it ran at 16 kilometers. The result revealed that the best saving was equivalent to 613 km/L at the speed of 30.6 km/hr.

Based on the research on creation of bas-relief molds for production of bas-reliefs made from boiled pineapple leafs conducted by Rachadasak Pengcum of which purpose was to help generate income for members of Pineapple Leaf Paper Community Enterprise Ban Pasang Wiwat Mueang District Chiang Rai Province it was found that the bas-reliefs need further improvements in terms of appearance and durability as well as the use of other natural raw materials to produce them. The researcher therefore has considered developing the previous research by applying other 3 valueless natural materials which include rice straw water hyacinth and banana stem skin to make bas-reliefs for different beautiful surfaces of the products. Also the quality of bas-reliefs has been comparatively investigated by surveying satisfactions of members of the Community Enterprise and visitors to the project towards the bas-reliefs made from rice straw water hyacinth and banana stem skin. The total period of questionnaire distribution was 3 months. There are 59 respondents administering the questionnaires most of whom (43 persons) are female which accounts for 72.88 per cent. The majority of the respondents (25 persons) obtained junior/senior secondary school diplomas or equivalent accounting for 42.37 per cent. 16 respondents or 27.12 percent are 60 years of age. As for satisfactions towards the bas-reliefs made from rice straw 89 times of “strongly agree” was selected whereas 126 times of “pretty much agree” 75 times of “fairly agree” and 5 times of “disagree” were marked by the respondents. Concerning the bas-reliefs made from water hyacinth 87 times of “strongly agree” was selected while 97 times of “pretty much agree” 110 times of “fairly agree” and 1 time of “disagree” were chosen. When asked about the bas-reliefs made from banana stem skin the respondents selected 77 times of “strongly agree” 99 times of “pretty much agree” 110 times of “fairly agree” and 8 times of “disagree”.

Nowadays energy conservation is widely recognized due to fuel crisis. Petroleum is one of the primary energy used in various aspects especially by factories which consume energy at very high rate. Air pollution has been caused for this reason. Lots of industrial sectors have paid attention to this problem and have found out in different ways to manage it. The purpose of this work was to apply compressed air energy which is zero emission energy as an alternative energy instead of fossil energy. This energy was used in a prototype small three-wheeler powered by an impact wrench. The vehicle carried two tanks of 10 liters of air which pressure is 90 bars. The three-wheeler used chains and gears to transmit power to wheels. The gear increased torque ratio of the impact wrench. An air valve was controlled by a sling-controlling lever. On rear wheel hub 3-speed gear was fitted to enable the car move conveniently according to speed of motor and road condition. Test results showed that air car could move with the maximum speed of 21.4 km/hr and the farthest distance of 1917 meters. The longest period of time which the car could move was about 5-6 minutes. The highest torque produced by impact wrench was 2.323 Nm at rotating speed of 3400 rpm. It was also found that between the rotating speed of 2000 and 4000 rpm the impact wrench produced the best performance and this is a good condition to be chosen for further research and development for maximum efficiency.