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This research examined thermal comfort in church buildings in Indonesia by making a comparison between three different Indonesian climatic regions using three different research models. A static model, an adaptation study model and a CFD simulation were used to find the similarities and differences between the results generated from determining thermal comfort in church buildings in the three regions. The comparison revealed that church buildings had different PMV scores at each measuring point that were inversely proportional to the subjects' response on thermal comfort inside the buildings, i.e. points adjoining with openings affect a low PMV score and a high perceived thermal sensation, and vice versa. The CFD simulation showed that changing the conditions of the openings affects air velocity and flow into the building, which influences the subjects' thermal comfort response inside the churches. [ABSTRACT FROM AUTHOR]

Background: Student performance determines learning achievement and how students absorb lessons in class. One of the factors that cause student performance to decline is physical fatigue, which arises because of the classroom's physical environment that does not support the teaching and learning process. Purpose: This study was conducted to determine the relationship between classroom's physical environmental conditions and fatigue among high school students. Methods: The study design used was cross-sectional. Data collection included measurements of physical environmental parameters (humidity, temperature, lighting, noise, air flow, ventilation, temperature control, room capacity, room area ratio per person, and school location) and measurements of fatigue among students using the Subjective Self Rating Test in the form of questionnaire. Total sample was 448 students in 10 private high schools, with inclusion criteria: the students are not sick in the last two weeks and 10th and 11th grade students from 10 private high schools. Results: The research showed classroom's physical environmental factors that affect fatigue among student's included temperature, relative humidity, air flow, and air conditioner. While the most dominant indicator that was related to the occurrence of students' fatigue was sex. Conclusion: Further research is needed on other factors that may cause fatigue among students in the classroom to support the conclusion of this research. [ABSTRACT FROM AUTHOR]

This present study contribute to provide a simple technology to early detect the phenomenon of spontaneous coal combustion. A new prototype is designated to detect the CO gas formation as a product of initial coal oxidation. Moreover, several parameters including coal quality, coal weight sample, ambient temperature, and air flow were employed to investigate the effects of each parameter to the CO formation time. The results show that the coal characterisation have a significant effect in the CO formation time where the coal having a higher fixed carbon and high grass calorific values provide the high liability of spontaneous coal combustion. However, these finding only occurred in low weight sample where in the high coal weight sample only fixed carbon plays the main role in determining the CO formation time. Furthermore, the prototype ambient temperature become the important parameter in the boosting of CO formation time where airflow only enhance the CO formation time in low temperature condition (below 29°C). Moreover, these findings opens a new sight in coal management, especially in Indonesia, where controlling the coal and atmosphere temperature could effectively prevent the spontaneous coal combustion especially in coal stockpile. Nevertheless, the other factor including airflow and coal weight sample also need perfect controlling because all of these factors potentially create a perfect environment to combust the coal spontaneously. [ABSTRACT FROM AUTHOR]

The effect of moisture content on ignition and combustion behavior of Chinese (HL) and Indonesian (YN) lignite were investigated. Particles with a size range of 75–105 μm with different moisture contents were injected in a bench-scale, electrically heated transparent reactor and the combustion of individual particles was observed with a high-resolution high-speed camera. Direct ignition observations indicated that most of the HL lignite particles underwent extensive fragmentation during ignition. Fragmentation was attributed to the explosive diffusion of volatiles and water vapor to the particle surface as a result of fast heating rate. Fragmentation reduced the particle size and increased the possibility of heterogeneous ignition of individual fragments. YN lignite particles on the other hand, underwent one-mode whole particle ignition upon heating. Higher moisture content caused a significant ignition delay in both lignite samples. 10% and 20% moisture in lignite samples resulted in around 83 and 160 ms delay in ignition for both coals. Higher intensity of fragmentation of HL particles during combustion compared to YN lignite resulted in shorter total particle combustion time at higher moisture contents. The findings of this study advanced the knowledge of the effects of moisture on ignition and combustion of low-rank coals. [ABSTRACT FROM AUTHOR]

Abstract: Indonesia is the third largest producer of cocoa bean in the world. One of the residues produced after removal of the cocoa bean from the fruit is cocoa pod husk (CPH). The objective of this work was to assess the use of CPH as a renewable energy source. CPH was sun-dried, crushed, and screened to obtain a particle size of less than 1mm. Five grams mixture of CPH and binder in the proportion of 70% and 30% by weight respectively was pelletized and dried at 50 °C for 5hours. Carbonization was performed at 400 °C for 2hours. The results show that CPH has a high heating value of 17.0MJ/kg. The air flow rate and fuel composition significantly affected the burning time and CO emission factor. The increase of carbonized CPH portion in the fuel increased the burning time of the pellet. The increase of air flow rate and carbonized CPH portion also increased the emission factor of CO. [Copyright &y& Elsevier]