| 41. |
- Gao, Chuansi, et al.
(författare)
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Moisture absorption, mass loss and evaporative resistance of permeable clothing in a transient condition
- 2006
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Ingår i: Journal of Donghua University. - 1672-5220. ; 23:5, s. 54-58
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Tidskriftsartikel (refereegranskat)abstract
- The water vapour resistance of clothing ensembles is not as commonly determined as dry thermal insulation. The measurement techniques are more complicated and the measurement values differ among laboratories. Due to complicated moisture transfer process through clothing ensemble, the moisture absorbed and evaporated varies in transient and steady state phases depending on properties, thickness of clothing, and environmental conditions. The purpose of this study was to measure moisture absorption inside hygroscopic underwear, hydrophobic and permeable outer wear as a function of time, to investigate mass loss from “skin” as well as from manikin, to quantify evaporative heat loss and total heat loss from manikin, to determine evaporative resistance of clothing. Manikin Tore was used by wearing wet “skin” to simulate sweating. Moisture content gain of the inner garment shows an exponential relation against time. Moisture in the outer permeable garment shows very small gain. On the contrary, mass loss directly from the wet skin decreases exponentially. The mass loss from the manikin is relatively stable throughout three test phases. The evaporative heat loss is about two thirds of the total heat loss from the sweating manikin. One hour measurement time is sufficient to get stable results while measuring the evaporative resistance of clothing ensembles with hygroscopic inner garment and permeable outer garment. The variation between the 1st hour and the 3rd hour is less than 5%. The length of transient period and measurement time requirement is dependent on the permeability, thickness of clothing ensembles and environmental conditions.
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| 42. |
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| 43. |
- Gao, Chuansi, et al.
(författare)
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Occupational heat stress assessment and protective strategies in the context of climate change
- 2018
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Ingår i: International Journal of Biometeorology. - : Springer Science and Business Media LLC. - 1432-1254 .- 0020-7128. ; 62:3, s. 359-371
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Tidskriftsartikel (refereegranskat)abstract
- Global warming will unquestionably increase the impact of heat on individuals who work in already hot workplaces in hot climate areas. The increasing prevalence of this environmental health risk requires the improvement of assessment methods linked to meteorological data. Such new methods will help to reveal the size of the problem and design appropriate interventions at individual, workplace and societal level. The evaluation of occupational heat stress requires measurement of four thermal climate factors (air temperature, humidity, air velocity and heat radiation); available weather station data may serve this purpose. However, the use of meteorological data for occupational heat stress assessment is limited because weather stations do not traditionally and directly measure some important climate factors, e.g. solar radiation. In addition, local workplace environmental conditions such as local heat sources, metabolic heat production within the human body, and clothing properties, all affect the exchange of heat between the body and the environment. A robust occupational heat stress index should properly address all these factors. This article reviews and highlights a number of selected heat stress indices, indicating their advantages and disadvantages in relation to meteorological data, local workplace environments, body heat production and the use of protective clothing. These heat stress and heat strain indices include Wet Bulb Globe Temperature, Discomfort Index, Predicted Heat Strain index, and Universal Thermal Climate Index. In some cases, individuals may be monitored for heat strain through physiological measurements and medical supervision prior to and during exposure. Relevant protective and preventive strategies for alleviating heat strain are also reviewed and proposed.
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| 44. |
- Gao, Chuansi, et al.
(författare)
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Perception of slipperiness, thermal comfort and wearability of footwear used on icy surfaces
- 2000
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Ingår i: Ergonomics for the new Millenium. - : Human Factors and Ergonomics Society. - 0945289138 ; , s. 522-525
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Konferensbidrag (refereegranskat)abstract
- The objectives of this study are to assess the perception of slipperiness, thermal comfort, and wearability of footwear used on icy surfaces, and the anti-slip effect of materials spread on ice using outdoor walking trials. Twenty-five subjects wore four types of footwear walking on five different icy surfaces. A five-point rating scale was used recording wearer's perception. The results showed that pure ice was perceived as very slippery. Spreading sand (180 g/m2) greatly decreased the slipperiness. Slip resistance, thermal insulation and wearability of footwear chosen were not properly integrated, and were ranked differently in four types of footwear. In addition to thermal insulation, prevention of slip and fall hazard by improving anti-slip property and wearability must also be priorities for development of footwear for use in a cold climate.
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| 45. |
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| 46. |
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| 47. |
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| 48. |
- Gao, Chuansi, et al.
(författare)
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Personal cooling with phase change materials to improve thermal comfort from a heat wave perspective
- 2012
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947. ; 22:6, s. 523-530
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedAbstract The impact of heat waves arising from climate change on human health is predicted to be profound. It is important to be prepared with various preventive measures for such impacts on society. The objective of this study was to investigate whether personal cooling with phase change materials (PCM) could improve thermal comfort in simulated office work at 34°C. Cooling vests with PCM were measured on a thermal manikin before studies on human subjects. Eight male subjects participated in the study in a climatic chamber (T(a) = 34°C, RH = 60%, and ν(a) = 0.4 m/s). Results showed that the cooling effect on the manikin torso was 29.1 W/m(2) in the isothermal condition. The results on the manikin using a constant heating power mode reflect directly the local cooling effect on subjects. The results on the subjects showed that the torso skin temperature decreased by about 2-3°C and remained at 33.3°C. Both whole body and torso thermal sensations were improved. The findings indicate that the personal cooling with PCM can be used as an option to improve thermal comfort for office workers without air conditioning and may be used for vulnerable groups, such as elderly people, when confronted with heat waves. PRACTICAL IMPLICATIONS: Wearable personal cooling integrated with phase change materials has the advantage of cooling human body's micro-environment in contrast to stationary personalized cooling and entire room or building cooling, thus providing greater mobility and helping to save energy. In places where air conditioning is not usually used, this personal cooling method can be used as a preventive measure when confronted with heat waves for office workers, vulnerable populations such as the elderly and disabled people, people with chronic diseases, and for use at home.
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| 49. |
- Gao, Chuansi
(författare)
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Phase-change materials (PCMs) for warming or cooling in protective clothing
- 2014
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Ingår i: Protective Clothing : Managing Thermal Stress - Managing Thermal Stress. - : Elsevier. - 9781782420323 - 9781782420408 ; , s. 227-249
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Bokkapitel (refereegranskat)abstract
- The various types of phase-change materials (PCMs), which absorb or release stored latent heat when they change phases causing cooling and warming effects, are described and the working principles are outlined. The various ways of incorporating PCMs into textiles for protective clothing are explored, and critical factors identified that determine the effectiveness of PCM cooling and warming effects. Examples of applications are given. Standards and testing, future trends and challenges are discussed.
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| 50. |
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