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- Kim, Yung-Bin, et al.
(author)
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Self-identified thermal comfort zone and perceived climate changes: a questionnaire study in temperate, tropical and cold climates
- 2017
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In: ; , s. 59-59
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Conference paper (peer-reviewed)abstract
- The present study was conducted to explore self-identified thermal comfort zone and the perceived climate changes of indigenes who live in temperate, tropical and cold climates. A questionnaire study was carried out in the following seven countries: Mongol (Bsk by Köppen’s climate classification), Sweden (Cfb), Korea (Dwa), Japan (Cfa), Fiji (Af), Indonesia (Af), and Malaysia (Af). A total of 125 Mongolians, 83 Swedish, 240 Koreans, 231 Japanese, 391 Fijian, 101 Malaysians, and 137 Indonesians participated in this questionnaire from Oct 2016-Jan 2017. The questionnaire consisted of 52 questions on self-identified thermal tolerance, behavioural thermoregulation, thermal neutral zone, thermal comfort, and perceived climate changes. The questionnaire was cross-translated between languages based on an original English version. The results showed that the self-identified thermal comfort zone in the summer or wet season was higher for tropical indigenes (24~27 °C for Malaysians and Indonesians) than for indigenes in cold climates (18~21°C for Mongolians and Swedish). For the winter or dry season, similar results were found. Interestingly, 21.8 % of Mongolians preferred indoor temperature lower than 15 °C whereas 25.0 % of Malaysians preferred indoor temperature higher than 27 °C in the winter (or dry) season. In particular, Koreans and Fijian perceived hotter summers and colder winters due to climate changes during the last five years when compared to other people.
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| 2. |
- Kim, Siyeon, et al.
(author)
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Regional differences in air velocity of microclimate inside clothing and bellows effect
- 2017
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In: Innovations in protective and e-textiles in balance with comfort and ecology. - 9788372838551 ; , s. 285-296
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Conference paper (peer-reviewed)abstract
- Despite of a crucial role of microclimate inside clothing in thermal comfort, air velocity inside clothing has been hardly reported, ever since Lewis et al (1969) demonstrated that air velocity of the still air layer on the naked human body was 0.25 m/s using colour schlieren cinephotography. This study was aimed to investigate the air velocity of microenvironment inside clothing and the bellows effects using an anemometer. Four male subjects participated in this study (age 24±5 yrs; height 178±5 cm; weight 76±7 kg). Each trial began with a 10 min sitting on a chair and walking on a treadmill at 5.0 km/h with 3% slope for 30 min thereafter at 25oC and 40%RH. Experimental clothing consisted of semi-impermeable long-sleeved t-shirts (polyester with polyurethane/silver coating), sportswear pants (cotton 100%). Air velocity was measured on the chest, scapula, and side by an anemometer (6244 System, KANOMAX, Japan) with 0.01m/s of measuring resolution. One-way ANOVA and repeated measures ANOVA were tested to investigate the differences of state and region. Post-hoc test was conducted by LSD and the critical p-value was set at p < 0.1. All values were represented as mean±SD. The results showed that the air velocity inside clothing was 0.09±0.04 m/s, 0.13±0.04 m/s, and 0.07±0.03 m/s on the chest, the scapula and the side, respectively in a sitting position. When subjects started to walk, it dramatically increased (p=0.025), and the greatest change caused by movement was presented in the side (0.51±0.32 m/s) followed by the chest (0.31±0.16 m/s) and the scapula (0.19±0.12 m/s). Air velocity in a static state and the change on the side were significantly greater than that on the scapula (p = 0.066, p = 0.054 respectively).
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| 3. |
- Halder, Amitava, et al.
(author)
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Muscle electrical activity changes over time during stair ascending until exhaustion
- 2018
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In: 22nd Congress of the International Society of Electrophysiology and Kinesiology (ISEK).
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Conference paper (peer-reviewed)abstract
- BACKGROUND AND AIM Non-stop stair ascending at maximum speed is required to reach a safe refuge level from deep underground structures, such as subways and in high-rise buildings in an emergency evacuation situation. Endurance of stair climbing and identifying the time of the onset of leg’s local muscle fatigue (LMF) are interests in evacuation research. The objective of this laboratory study was to investigate leg muscles’ electrical activity changes in electromyography (EMG) over time during stair ascending until exhaustion on a stair machine. METHODS The developed muscle activity rate change (MARC) in muscle activity interpretation square (MAIS) was used to evaluate leg LMF at constant step rates equivalent to individual 100% VO2max level. This result is used to validate the MAIS. The MAIS is based on the four assumptions of EMG muscle activity (AMP and MDF) rate change (MARC) over the ascending durations. An increase in AMP and MDF is an indication of: 1) muscle force increase. An increase in AMP and a decrease in MDF is an indication of: 2) muscle fatigue. A decrease in AMP and MDF is an indication of: 3) muscle force decrease. A decrease in AMP and an increase in MDF is an indication of: 4) fatigue recovery. MARC was observed on the both AMP and MDF values of the ten equal length divisions (10%) in the total ascending period (100%). The averages of the MDF and normalized AMP for each equally divided 10% period were calculated for all subjects to yield 1 data point, and totally 10 data points. These 10 periodical average AMP and MDF data points (10-100%) and the changes between the unit times represent the MARC for each muscle during ascension. Later, both the AMP and MDF MARC values are combined to get one final point for each tenth percentile duration and presented into the MAIS, which is used to estimate muscle fatigue.MARC values are derived by the following equation:∆MARC = (x_n-x_(n-1))/(t ̅⁄10) where, ΔMARC is change in a selected parameter (AMP and MDF) over normalized time;x_n is the selected parameter (AMP and MDF) value at each normalized time point n;x_(n-1) is the selected parameter value at a normalized time point n-1;t ̅ is the average duration in seconds for the stair ascending;10 is the total number of normalized times.RESULTS The appearances of MARC points in the MAISs showed the state of muscle activity changes over time during this predetermined and constant ascending speed at 100% of VO2max on a stair machine. Most of the muscles’ MARC points at 90-100% periods were found in the muscle fatigue squares. Moreover, individual AMP and MDF analysis showed significantly increased and decreased, respectively, which supported the interpretations made by the MAIS.CONCLUSIONS These stair ascending EMG results supported the MARC and MAIS when interpreting muscle fatigue. They seem promising to interpret muscle activity changes per unit time during dynamic tasks over the whole working duration in different activities.
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