Husin Bugis

Student Improvement by Applying the Numbered Heads Together (NHT) Approach to Basic Subjects of Vocational Competence in a Vocational High School in Indonesia.

Abstract This research aims to improve the learning activity and achievement of a 10th grade class made up of 30 students in a vocational high school located in the city of Surakarta, Indonesia, by applying the Numbered Heads Together (NHT) approach. The experiment was divided into two stages of four activities each: planning, implementation, observation, and reflection. The comparative descriptive procedure was then used to analyze the data. Prior to the researach implementation, the learning activity was relatively low in the pre-stage of the experiment. However, after the NHT approach, the percentage of active students increased in stage 1 and stage 2. The result of the test also suggested a similar trend in student achievement. From this it can be concluded that the application of the NHT learning model improves engagement within the learning activity as well as the level of achievement.

Preliminary experiment on fuel consumption and emission reduction in SI engine using blended bioethanol–gasoline and radiator tube-heater

Abstract The objective of this research is to investigate the reduction in fuel consumption and emission in spark ignition engine using blended bioethanol-gasoline and novel radiator-tube heater. Different percentages of ethanol – 0, 5, 10, 15, 20, 25 and 30% – are employed. The blended fuel is then pre-heated by sending it into a tube-heater-installed upper tank radiator which has different shape. The results show a significant reduction in fuel consumption and emission in engine. The best economical fuel consumption occurs in the tube-heater with a fin pipe of 10 mm space at 2.153 × 10−3 cc per cycle or 5.632%. However, the most economical fuel consumption occurs when 25% of bioethanol is added to fuel at 3.175 × 10−3 per cycle. This decreases fuel consumption by 8.306%. The highest decrease in fuel consumption occurs when fuel blended with 25% of bioethanol and tube-heater of 10 mm 6.236 × 10−3 cc per cycle or 16.313% is combined. In terms of emission reduction, the tube-heater with a space of 20 mm between fins (Tube 20) using a fuel mixture of 25% ethanol and 75% gasoline produced the lowest CO emissions.