• Title/Summary/Keyword: Thermal responses

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Evaluation of Physiological Responses and Subjective Sensation in Different Sock Materials (양말 소재별 인체생리적 반응 및 주관적 감각평가)

  • 김칠순;정명희
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.8
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    • pp.1475-1483
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    • 2001
  • The purpose of this study was to determine the physiological responses and subjective sensation according to fiber content of socks. Six female students participated in the wear trial test which was conducted in controled environmental chamber with 26${\pm}$1$^{\circ}C$ and 60${\times}$3%. R.H.SAS program was used for statistical analysis. The results of this study were as follows. Mean skin temperature was significantly different among three different socks. AWNP socks had the highest mean skin temperature and instep temperature. Also relative humidity in the microclimate of socks as well as heart rate were influenced by fiber content of socks, However, test of subjective sensation such as thermal, humid, comfort sensation showed that there was no significant difference among three different socks thermal sensation during the exercise and recovery period.

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Free vibrational behavior of bi-directional perfect and imperfect axially graded cylindrical shell panel under thermal environment

  • Pankaj S. Ghatage;P. Edwin Sudhagar
    • Structural Engineering and Mechanics
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    • v.85 no.1
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    • pp.135-145
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    • 2023
  • This study presents the free vibrational responses of bi-directional axially graded cylindrical shell panels using 3D graded finite element approximation under a temperature field. The cylindrical shell panel is graded in two directions and made of metal-ceramic materials. To extract material properties, the Voigt model is combined with a Power-law material distribution. Convergence and validation studies are performed on the developed computational model to ensure its accuracy and effectiveness. Furthermore, a parametric study is performed to evaluate the developed model, which demonstrates that geometrical parameters, imperfect materials (porosity), support conditions, and surface temperature all have a significant impact on the free vibration responses of a bi-directional axially graded cylindrical shell panel in a thermal environment.

The Changes of Psychological and Physiological Emotional Responses According to Change of the Index of Predicted Mean Vote (PMV) due to Air Conditioning Types (공조방식에 의한 예상 온열감 반응(PMV) 변화에 따른 심리/생리적 감성반응의 변화)

  • Kim, Bo-Seong;Min, Yoon-Ki;Min, Byung-Chan;Kim, Jin-Ho
    • Science of Emotion and Sensibility
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    • v.14 no.4
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    • pp.645-652
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    • 2011
  • This study examined changes of both psychological and physiological emotional responses according to change of the PMV (predicted mean vote) in the heating and the cooling air conditions. For this purpose, the changes of PMV were induced by the heating and cooling operations of the HVAC (heating, ventilation, and air conditioning) systems. In addition, positive/negative and arousal/relaxation were measured as the participant's psychological emotional responses, and HR (heart rate) was measured as the participant's physiological emotional responses. As a result, in same range of the PMV, both psychological and physiological emotional-responses were changed by air conditioning. It is suggested that occupant's emotional responses would depend on the operational conditions of heating and cooling in indoor thermal environments, and both psychological and physiological emotional response should be considered when occupants try to match the indoor thermal environments to their thermal expectations.

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Characteristics of Thermal Environments and Evaluation of Thermal Comfort in Office Building in Winter (겨울철 사무실내 온열환경 특성 및 쾌적성 평가)

  • Bae, G.N.;Lee, C.H.;Lee, C.S.;Choi, H.C.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.2
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    • pp.310-318
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    • 1995
  • In this study, indoor thermal parameters were measured to investigate the characteristics of thermal environments and 138 occupants were questioned to evaluate Korean thermal comfort in office building in winter. Thermal sensation was estimated by using PMV(Predicted Mean Vote) and ET*(New Effective Temperature) indices. Comparing present experimental result with international standards and that of other research, Korean thermal responses were discussed. Seasonal difference between summer and winter was also discussed. It was found that TSV(Thermal Sensation Vote) is more sensitive than PMV to the variation of temperature and that the measured percentage of dissatisfied is higher than PPD(Predicted Percentage of Dissatisfied) in real office building environments. By regression analysis, the following regression equation has been obtained; TSV=0.432ET*-8.814 and neutral temperature is $20.4^{\circ}C$ in this case. Thermal comfort range based on 80% satisfaction is also $19.4{\sim}22.4^{\circ}C$.

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Characteristics of Thermal Environments and Evaluation of Thermal Comfort in Office Building in Summer (여름철 사무실내 온열환경 특성 및 쾌적성 평가)

  • Lee, C.H.;Bae, G.N.;Choi, H.C.;Lee, C.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.3
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    • pp.206-217
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    • 1994
  • In this study, indoor thermal parameters were measured to investigate the characteristics of thermal environments and 212 occupants were questioned to evaluate Korean thermal comfort in office building in summer. Thermal and comfort sensations were estimated using PMV(Predicted Mean Vote) and ET* (New Effective Temperature) which are most widely used nowadays. Comparing this experimental result with international standards and that of other research, Korean thermal responses were discussed. It was found that TSV(Thermal Sensation Vote) is more sensitive than PMV to the variation of temperature and that the measured percentage of dissatisfied is higher than PPD(Predicted Percentage of Dissatisfied) in real office building environments. By regression analysis, the following regression equation has been obtained: TSV=0.461ET*-11.808 and neutral temperature is $25.6^{\circ}C$ in this case. Thermal comfort range based on 80% satisfaction is also $24.0{\sim}26.8^{\circ}C$, which is about $1^{\circ}C$ higher than that of ANSI/ASHRAE Standard.

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Layering Effects on Clothing Microclimate, Clothing Insulation and Physiological Responses

  • Park, Joonhee;Yoo, Shinjung
    • International Journal of Human Ecology
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    • v.14 no.2
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    • pp.93-103
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    • 2013
  • This study investigated the relationship of clothing microclimate and physiological responses in order to examine the layering effects on the clothing microclimate as an index to predict clothing thermal insulation ($I_{cl}$). Experiments were conducted in a $15^{\circ}C$ environment on six physically active males. Increased clothing layers resulted in higher mean temperature inside the clothing ($\bar{T}_{cl}$) and $I_{cl}$. The $I_{cl}$ had a high correlation with: $\bar{T}_{cl}$ (r = 0.556), the difference between the innermost surface temperature and the outermost surface temperature at the chest (DST) (r = 0.549) and the temperature inside clothing at the abdomen (r = 0.478). $\bar{T}_{cl}$ had the highest correlation with the temperature inside clothing at the abdomen (r = 0.889). $\bar{T}_{cl}$ also had the highest correlation with $\bar{T}_{sk}$ (r = 0.860). The results showed that the relationship between $I_{cl}$ and $\bar{T}_{cl}$ was linear (p < .01). Thermal comfort had a negative correlation with $\bar{T}_{cl-thigh}$ (r=-0.411) and $\bar{T}_{cl}$ (r = -0.323) (p < .01.)

Numerical study of temperature dependent eigenfrequency responses of tilted functionally graded shallow shell structures

  • B, Chandra Mouli;K, Ramji;Kar, Vishesh R;Panda, Subrata K;K, Lalepalli Anil;Pandey, Harsh K
    • Structural Engineering and Mechanics
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    • v.68 no.5
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    • pp.527-536
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    • 2018
  • The free vibration frequency responses of the graded flat and curved (cylindrical, spherical, hyperbolic and elliptical) panel structures investigated in this research considering the rectangular and tilted planforms under unlike temperature loading. For the numerical implementation purpose, a micromechanical model is prepared with the help of Voigt's methodology via the power-law type of material model. Additionally, to incur the exact material strength, the temperature-dependent properties of each constituent of the graded structure included due to unlike thermal environment. The deformation kinematics of the rectangular/tilted graded shallow curved panel structural is modeled via higher-order type of polynomial functions. The final form of the eigenvalue equation of the heated structure obtained via Hamilton's principle and simultaneously solved numerically using finite element steps. To show the solution accuracy, a series of comparison the results are compared with the published data. Some new results are exemplified to exhibit the significance of power-law index, shallowness ratio, aspect ratio and thickness ratio on the combined thermal eigen characteristics of the regular and tilted graded panel structure.

An Analysis of the Physiological and Psychological Responses Elicited When Wearing an Aerogel Cold Protective Jacket in Airflow (에어로젤 방한 재킷 착용시의 기류 유무에 따른 생리·심리학적 특성 분석)

  • Seong-Suk Kim;Su-Young Son;Hee-Eun Kim
    • Human Ecology Research
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    • v.62 no.2
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    • pp.317-326
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    • 2024
  • This study evaluated the thermal physiological and psychological responses elicited when wearing cold protective jackets with aerogel fillings in two cold environments, one without air velocities and one with air velocities (2.3 m·s-1), at an air temperature of 10℃. The participants were five healthy young males. Measures were taken of physiological parameters, blood pressure (BP), heart rate (HR), core temperature, oxygen uptake (Vo2), and microclimate (temperature and humidity). The psychological parameters evaluated were thermal and wetness sensation. No differences were observed in systolic blood pressure, heart rate, and oxygen intake between the conditions. At tympanic temperature, a significant difference was observed between the conditions during exercise (p<.05); . A significant difference was observed in the microclimate temperature of the clothing according to the airflow, and temperature changes in the chest and back revealed different patterns. Significant differences were observed in thermal sensation (whole body (p<.05), chest (p<.05), back (p<.01)) between airflow conditions. The results therefore indicate that cold protective jackets with an aerogel filling are suitable for people operating in low-temperature and airflow environments.

The Effects of Parka on Subject Wear Sensation as to Thermal Resistance (파카의 보온성에 따른 착용감에 관한 연구)

  • Lee Yoon-Jung;Lee Soon-Won
    • Journal of the Korean Society of Clothing and Textiles
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    • v.13 no.3 s.31
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    • pp.295-303
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    • 1989
  • This study is to measure the thermal resistance of 7 types of Parka of different materials with thermal manikin and to compare their effects on physiological responses & subjective wear sensations. Following are the results obtained from the experiments 1) From the thermal manikin experiment, i) As an outer layer, although not significant, water proof fabric was warmer than water proof-vapor permeable fabric. ii) In case of insulating material, down was better for thermal resistance than polyester wadding of the same thickness. Moreover, as the down was thicker, it had more efficiency in thermal resistance. However, the marginal efficiency of thickness was found to be decreasing. 2) From the male-subject experiments, i) Chest temperature, mean skin temperature & microclimate temperature showed the same results on thermal resistance as those of the thermal manikin experiment. ii) Only during rest periods, there was a significant difference among 5 insulating materials in the sense of microclimate humidity. The almost same conclusion was obtained from the above experiments. Even the outer layer did not significantly affect thermal resistance & subjective wear sensation, insulating materials had a significant influence upon them. But in case of 3.5 cm down, it gave less comfortable than that of the thinner. Therefore the optional one for the best comfort & thermal resistance among 7 combinatins is the outer layer of water proff-vapor permeable & insulating material of 2.1 cm down.

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