Thermal comfort is crucial in satisfaction and maintaining quality sleep for occupants. In this study, we investigated the comfort temperature in the bedroom at night and sleep quality for Indonesian students during summer and winter. Eighteen male Indonesian students aged 29 ± 4 years participated in this study. The participants had stayed in Japan for about six months. We evaluated the sleep parameters using actigraphy performed during summer and winter. All participants completed the survey regarding thermal sensation, physical conditions, and subjective sleepiness before sleep. The temperature and relative humidity of participants’ bedrooms were also measured. We found that the duration on the bed during winter was significantly longer than that during summer. However, sleeping efficiency during winter was significantly worse than that during summer. The bedroom temperature of the participants was in the range of comfort temperature in Indonesia. With the average bedroom air temperature of 22.2 °C, most of the participants still preferred “warm” and felt “slightly comfortable” during winter. The average comfort temperature each season calculated using the Griffiths method was 28.1 °C during summer and 23.5 °C during winter. In conclusion, differences in adaptive action affect bedroom thermal conditions. Furthermore, habits encourage the sleep performance of Indonesian students.

No abstract

An environmentally sound management of plastic waste in Semarang City is necessary due to increasing plastic waste generation; limited capacity of Jatibarang Final Disposal; dangers of open burning of plastic waste; pollution of water resources both surface water and sea water; and limited amount of raw materials for the manufacture of plastic resin. This study aims to present the assessment of plastic waste management from collection to final disposal as well as its estimated generation. A field study was conducted to identify the material flow of plastic waste, particularly PET bottles. To estimate the potential generation of plastic waste, a top-down approach was used. The volume of plastic waste in Semarang reached 16.28% of the total municipal waste, in which the highest part of inorganic waste. The total estimated plastic waste generation in Semarang City, particularly from households, was 1012.486 m3/day. There is an urgent need for improving the plastic management in Semarang due to existing low recycling rate.

A traffic accident was one of the leading cause of death in Indonesia. Toll Road is one of the places where traffic accidents occur. In 2007-2017 there were 501 accidents at Semarang Toll Road. Accident in Semarang Toll Road has a variety of severity. The most severe case is death. A traffic accident can lead to death. One of the ways to decrease the number of the accident was decreased the severity of the accident. This achieved by making a prediction model. The prediction model can predict the severity of the accident based on the attribute affecting the severity of the accident. In this research, Days, Type of Road, Weather, Condition of Road, Time of the accident, Sex of Driver, and Type of Vehicle were chosen as attributes to make prediction model of accident severity. Naive Bayes algorithm was used to make the model which can predict accident severity. The result was an accident prediction model with an accuracy of 39.49% to predict accident severity and the probability of an accident.

The Crude Palm Oil industry has now become the largest agricultural industry in Indonesia. Nevertheless, the growth of CPO industry could also bring negative impacts on the environment if the company does not control their emissions and discharges properly. Life-cycle Assessment (LCA) is one of the tools that can assess the environmental impacts due to CPO production activities. This study aims to assess the potential environmental impacts arising from the CPO production system at Mill J, PT XYZ, Sumatera Island by using Eco-indicator 99. Based on this study, in 2015, the process in plantation and mill contributed to climate change category was 0.013 DALY or after normalized 202 Pt. Meanwhile, the land use category has 395 PDF*m2yr or 30.8 Pt. Meanwhile, all of the other categories were less than 30.8 Pt, hence, the highest impact of this CPO production system is climate change at the activities in industrial estate (fertilizers usage) and industry (emitted from waste water of palm oil mill).

Manusia sebagai subyek yang memiliki keterbatasan dalam kerja, sehingga menyebabkan terjadinya kesalahan. Kesalahan manusia yang dilakukan mengakibatkan menurunnya tingkat kewaspadaan masinis dan asisten masinis dalam menjalankan tugas. Tingkat kewaspadaan dipengaruhi oleh 5 faktor yaitu keadaan monoton, kualitas tidur, keadaan psikofisiologi, distraksi dan kelelahan kerja. Metode untuk mengukur 5 faktor yaitu kuisioner mononton, kuisioner Pittsburgh Sleep Quality Index (PSQI), kuisioner General Job Stress dan kuisioner FAS. Sedangkan untuk menguji tingkat kewaspadaan menggunakan Software Psychomotor Vigilance Test (PVT). Responden yang dipilih adalah masinis dan asisten masinis, karena jenis pekerjaan tersebut sangat membutuhkan tingkat kewaspadaan yang tinggi. Hasil pengukuran kemudian dianalisa menggunakan uji regresi linear majemuk. Dalam penelitian ini menghasilkan keadaan monoton, kualitas tidur, keadaan psikofisiologi, distraksi dan kelelahan kerja berpengaruh secara simultan terhadap tingkat kewaspadaan. Hal ini dibuktikan dengan ketika sebelum jam dinas, hasil uji F-hitung keadaan monoton, kualitas tidur, keadaan psikofisiologi adalah sebesar 0,876, sedangkan untuk variabel distraksi dan Kelelahan Kerja (FAS) terhadap tingkat kewaspadaan memiliki nilai 2,371. pada saat sesudah bekerja variabel distraksi dan kelelahan kerja (FAS) terhadap tingkat kewaspadaan memiliki nilai F-hitung 2,953,dan nilai 0,544 untuk keadaan monoton, kualitas tidur, keadaan psikofisiologi. Faktor yang memiliki pengaruh terbesar terhadap tingkat kewaspadaan sebelum jam dinas yaitu faktor kualitas tidur, sedangkan untuk sesudah jam dinas adalah faktor kelelahan kerja.

Abstract-E-waste management involves the selection of ewaste location of dismantling and sorting facility (DSF). Unfortunately, Indonesia, at present, has no disposal sites. Site selection decision complexity involves a lot of criteria to filter the various alternative locations. As the initial step, the aims of this study is to select the optimal location of DSF in Indonesia using multi-criteria decision analysis. In this case, Analytic Hierarchy Process (AHP) model was applied. Eight criteria were selected to choose the optimal location, e.g. local population (C 1 ), population served (C 2 ), percentage of monthly non-food expenditure (C 3 ), distance from existing e-waste dismantling and sorting facility (C 4 ), average house per unit (C 5 ), unemployed population (C 6 ), financial status of local population (C 7 ), and distance from the nearest port (C 8 ). Data of eight criteria then were ranked based on the objective function of each criterion, which were maximizing function (C 1 , C 2 , C 3 , C 4 , C 6 ) and minimize function (C 5 , C 7 , C 8 ). The results of those ranking then summed based on the weight resulted from AHP, and finally generated five main alternatives in selecting e-waste DSF. Based on this model, West Java was selected as the optimal location of e-waste DSF. West Java is one of the most populated provinces in Indonesia and located near the capital city of Indonesia.

The Two for One Twister (TFO) machine emits very disturbing noise and the noise exposes the workers while performing their tasks. The noise also lead to works stress. So, it is necessary to determine the relationship between the noise and work stress of TFO machine operators. This study  was  conducted  by measuring  the  noise  of  TFO  engine  with  Enviro-meter  and then correlating the noise and work stress with SPSS 16 software. Spearman correlation test results showed that a strong correlation between noise with work stress (p value = 0.042). In order to reduce the noise level that will decrease stress for workers, Fault Tree Analysis was conducted to determine the source of the noise. Based on the qualitative analysis of FTA, the causes of the noise were as follows: the lubricating oil was not applied, seal of oil valve leaked, bearing was not replaced (2 years economic life), the traveler was not replaced (10 days economic life), and the Doubling machine was troubled. Based on the quantitative analysis of the probability of job stress of TFO machine operator due to noise TFO machines from a known probability of 0.041, hence, the system was feasible for use.