Homogeneous catalysts and heterogeneous catalysts are two types of catalysts used in the transesterification reaction process to produce biodiesel. Homogeneous catalysts that are commonly used are NaOH and KOH, while heterogeneous catalysts are CaO, super base CaO and Zeolite. This research was conducted to determine the contribution of catalysts NaOH, CaO, super base CaO, and zeolite to the quality of biodiesel produced from bulk palm oil, The reaction process is carried out in a Stirred Tank Flow Reactor equipped with a condenser. The results showed that the use of homogeneous catalysts could increase the acquisition of biodiesel but generally triggered high acid levels in the reaction products. Whereas heterogeneous catalysts can reduce biodiesel acid numbers, although the acquisition of biodiesel is lower than homogeneous catalysts.
Prospective teacher's metacognition knowledge such as declarative knowledge, procedural knowledge, and conditional knowledge is becoming crucial in the development of an efficient learning design. This lead to the urgency in measuring the level of metacognitive knowledge of prospective teachers. Currently, rubric to measure prospective teacher's metacognition knowledge in designing learning instruction is very limited. Therefore, this study aims to develop a rubric to assess metacognition knowledge in designing learning instruction. The Research and development methods are employed with the development design model including the preliminary study phase, development study phase, and evaluation stage. The rubric prototype resulted includes declarative, procedural and conditional knowledge in designing learning instruction on GPA aspects, learning objectives, learning materials, learning strategies, learning steps, learning media, learning resources, and learning outcomes assessment.
One of the most important needs in the biodiesel industry is the availability of catalysts. The catalyst most commonly used in making biodiesel is a homogeneous catalyst. However, the use of this catalyst has a weakness, namely that it is difficult to separate from the reaction mixture so that it will be wasted as waste which can cause environmental pollution. To overcome this, it is necessary to substitute a homogeneous base catalyst with a heterogeneous base catalyst. In this study, biodiesel production was carried out through the transesterification reaction of palm oil and methanol using three types of heterogeneous catalysts, namely zeolite, ZnO, and Al2O3. The results showed that the three types of catalysts can be used to become catalysts in the biodiesel production process. Of the three catalysts, the most effective use for biodiesel production from palm oil is the Al2O3. The characteristics of the biodiesel produced also meet the quality standards set out in the Indonesian National Standard.
The self-efficacy of prospective teachers is fostered through a program to prepare prospective teachers. Self-efficacy is one factor that influences personal and professional development in the future to become a professional teacher. The research aimed to investigate the impact of metacognition preparation in designing learning programs on prospective chemistry teachers' self-efficacy. Descriptive qualitative research is used as a method to interpret the data obtained. The subjects of this study were 34 students of the fifth semester of the Chemistry Education Department of the 2019/2020 academic year at one of the LPTKs in the city of Makassar. Data collection was carried out using a self-efficacy questionnaire adapted from the Science Teaching Efficacy Belief Instrument-Pre service (STEBI-B), which includes the dimensions of Personal Science Teaching Efficacy (PSTE) and Science Teaching Outcome Expectancy (STOE). The questionnaire data were analyzed by means of the average class score. The results showed that the metacognition debriefing program in designing learning could increase student self-efficacy as seen from the increase in the average class score at four stages of implementation, namely: 61.5; 66.1; 67.9; and 72.2. The students' average self-efficacy scores on the PSTE dimension were: 33.5; 38.2; 39.0; 41.8. The mean score of student self-efficacy in the STOE dimension was 28.0; 28.0; 28.9; 30.4. Student self-efficacy increased in both dimensions with higher PSTE scores than STOE scores.
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