RESUMEN
The purpose of this study was to elucidate the effect of urban morphology representing sky view factor (SVF) on urban microclimate and on human thermal responses. The physical environments and the changes in body temperatures as well as psychological responses were investigated in summer in Bucheon, Korea. The dry bulb temperature ranged from 31.5 °C at SVF 0.082 site to 35.7 °C at SVF 0.922 site. Most of the environmental elements were statistically correlated to the SVF: the dry bulb temperature R (2) = 0.602, UVB R (2) = 0.556 and the illumination level R (2) = 0.609. The mean skin temperature increased up to 36.0 °C at the SVF 0.940 site and decreased to 33.9 °C at the SVF 0.082 site. The mean skin temperature was statistically correlated to the SVF (p = 0.005). However, the core body temperature was not correlated to SVF because of time delay effect to the previously exposed thermal environment. In the investigation of thermal acceptability, only 5 % of subjects were dissatisfied with the road that was covered with plentiful trees; in contrast, approximately 50 % of subjects were dissatisfied with the road with poor solar obstacles in the summer. The thermal stress was affected by the urban morphology, and the plentiful urban greening improved thermal comfort.
Asunto(s)
Temperatura Corporal , Microclima , Peatones/psicología , Sensación Térmica , Adolescente , Adulto , Ciudades , Femenino , Humanos , Masculino , República de Corea , Estaciones del Año , Temperatura , Caminata , Adulto JovenRESUMEN
A total of 58 healthy subjects participated to elucidate the influence of indoor and outdoor temperatures on blood flow. After walking outdoors for 20 min, the blood flow rate of a subject was measured. The subject then entered a classroom and studied for 120 min, and afterwards, the blood flow rate was measured again. The subjects were exposed to outdoor temperature ranging from -2.5 to 33.7°C. During the summer, the average blood flow rate after walking outdoors was 45.95 ± 25.790 TPU (tissue perfusion units); after the class, this decreased to 36.14 ± 21.837 TPU (p<0.05). During the autumn, the blood flow rate decreased from 27.69 ± 12.334 TPU to 12.47 ± 12.255 TPU (p<0.001). When the outside air temperature was below 3°C, the blood flow rate indoors increased significantly from 6.74 ± 3.540 TPU to 13.95 ± 11.522 TPU (p<0.05). In a comfortable and healthy environment, the blood flow rate was not constant but fluctuated between 15 TPU and 40 TPU.
Asunto(s)
Dedos/irrigación sanguínea , Flujo Sanguíneo Regional/fisiología , Temperatura , Ambiente , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
A total of 25 college students participated in a study to determine when they would use an air conditioner during a lecture in a university classroom. The ambient temperature and relative humidity were measured 75 cm above the floor every minute. Skin temperatures were measured every minute at seven points, according to the recommendation of Hardy and Dubois. The average clothing insulation value (CLO) of subjects was 0.53 ± 0.07 CLO. The mean air velocity in the classroom was 0.13 ± 0.028 m/s. When the subjects turned the air conditioner both on and off, the average ambient temperatures, relative humidity and mean skin temperatures were 27.4 and 23.7 °C (p = 0.000), 40.9 and 40.0% (p = 0.528) and 32.7 and 32.2 °C (p = 0.024), respectively. When the status of the air conditioner was changed, the differences of skin temperatures in core body parts (head, abdomen and thigh) were not statistically significant. However, in the extremities (mid-lower arm, hand, shin and instep), the differences were statistically significant. Subjects preferred a fluctuating environment to a constant temperature condition. We found that a changing environment does not affect classroom study.
Asunto(s)
Aire Acondicionado , Temperatura Cutánea/fisiología , Sensación Térmica/fisiología , Abdomen/fisiología , Adolescente , Adulto , Femenino , Cabeza/fisiología , Humanos , Humedad , Extremidad Inferior/fisiología , Masculino , Instituciones Académicas , Temperatura , Extremidad Superior/fisiología , Adulto JovenRESUMEN
The hypothesis of this study is that the air conditioning temperature and thickness of the chair cushion affect a man's scrotal, and consequently testicular, temperature. Ten healthy male subjects volunteered for the study (age: 23.4 +/- 2.4 years; height: 173.8 +/- 5.09 cm; weight: 71.6 +/- 9.7 kg; body fat ratio: 18.6 +/- 4.1%). The air conditioning temperature was controlled at 18 degrees C to represent the heating season, and at 26 degrees C to represent the cooling season. The thickness of the chair cushions was varied from 0 to 8 cm at 2 cm intervals. The changes in the scrotal surface temperature (SST) and buttock skin temperature were measured for 120 min. At the ambient temperatures (t(a)) of 18 and 26 degrees C, the average SST were 33.76 +/- 1.28 and 35.02 +/- 0.54 degrees C for the chair cushion thickness (C(thk)) of 0 cm, 33.87 +/- 1.07 and 34.96 +/- 0.75 degrees C for C(thk) 2 cm, 33.91 +/- 0.84 and 35.03 +/- 0.85 degrees C for C(thk) 4 cm, 34.42 +/- 0.89 and 35.02 +/- 0.63 degrees C for C(thk) 6 cm, and 34.65 +/- 1.21 and 34.99 +/- 0.62 degrees C for C(thk) 8 cm respectively. SST was significantly affected by the air conditioning temperature (p < 0.001), but was not statistically correlated with the chair cushion thickness.
Asunto(s)
Aire Acondicionado , Temperatura Corporal , Diseño Interior y Mobiliario , Escroto/fisiología , Adulto , Humanos , MasculinoRESUMEN
As Koreans habitually sit on the heated floor in their residential buildings, the male testis is directly exposed, and is therefore affected by the floor surface temperature. The purpose of this study was to investigate the changes in the scrotal temperature of the subjects in a sedentary posture over the heated floor. A rigid screening test was performed to select healthy subjects. Finally, six college students volunteered to participate in the experiments. Two experiments were performed in a controlled environmental chamber. Experiment I was designed for a low metabolism state, with the subjects reading a book in a sedentary posture for 50 min. The floor surface temperature (tf) was controlled by varying the temperature of water (tw) flowing into the floor coil from 15 to 50 degrees C, at 5 degrees C intervals. Experiment I revealed that the final scrotal surface temperature was 32.27, 32.62, 33.51, 33.34, 34.14, 34.28, 34.34 and 35.04 degrees C at the tw 15 degrees C (tf 17.0 degrees C), 20 degrees C (tf 20.8 degrees C), 25 degrees C (tf 24.1 degrees C), 30 degrees C (tf 27.8 degrees C), 35 degrees C (tf 31.7 degrees C), 40 degrees C (tf 35.9 degrees C), 45 degrees C (tf 38.6 degrees C) and 50 degrees C (tf 42.2 degrees C), respectively. At tf 17.0 and 20.8 degrees C, the scrotal temperature exhibited a declining pattern and a low temperature for spermatogenesis. At tf 24.1, 27.8 and 31.7 degrees C, however, the thermal regulatory system of the scrotum and testis was activated appropriately. On the contrary, scrotal temperature ascended at tf 35.9, 38.6 and 42.2 degrees C. Of the six subjects, two subjects demonstrated scrotal temperatures above 35 degrees C at tf 38.6 degrees C and four subjects exhibited scrotal temperatures above 35 degrees C at tf 42.2 degrees C. Experiment II was designed for a high metabolism state, with the subjects playing a card game in a sedentary posture for 180 min. The tf was controlled by varying the tw from 30 to 40 degrees C, at 5 degrees C intervals. Experiment II revealed that the final scrotal temperature was 33.43, 34.78 and 35.61 degrees C, and the difference between the initial and final scrotal temperatures was +0.34, +1.06 and +2.24 degrees C, at tw 30 degrees C (tf 27.8 degrees C), 35 degrees C (tf 31.7 degrees C) and tw 40 degrees C (tf 35.9 degrees C), respectively. The scrotal temperature was affected by the floor surface temperature and by the rate of metabolism of the subject in a sedentary posture. As derived from regression analysis, the recommended surface temperature of a heated floor is within 23-33 degrees C under the assumption that scrotal and consecutively testicular temperature above 35 degrees C impairs spermatogenesis.