The purpose of this study was to evaluate thermal comfort properties of surgical gowns made of dual functional finish cotton and nonwoven fabrics which have barrier properties of blood and micro-organism. Four types of surgical gowns, which were made of nonwoven fabrics with finish or without and were made of cotton with finish or without, were tested. The thermal insulations of four surgical gowns were measured with thermal manikin. Subjective experiments on thermal comfort, skin temperature and clothing microclimate were conducted. Six male subjects, between 26 and 28 years age old, participated in the wear trials tests. Typical activities for surgeons in the operation theater were simulated during the experimental sessions. Air temperature in a climate chamber was kept at 22°C and its humidity was 60%RH. Air velocity was controlled at less than 0.15 m/s. Inner radiant temperature was almost equal to the air temperature. Basic thermal insulation of the dual functional finished nonwoven surgical gown was 0.87 clo, which was slightly higher than that of untreated (0.84 clo). However, the skin temperature of the subject wearing. a dual functional finished surgical gown was significantly lower at P<.05. When the subject wears the dual functional finished gown, the amount of sweating was less than that when wearing untreated. Microclimate temperature and humidity of dual functional finished surgical gown were lower than untreated and it was statistically significant. There was no significant difference in subjective humid and overall comfort sensation between finished and untreated ones. Thermal sensation of dual functional finished one was significantly different from untreated one only during the first exercise. The results of this study indicate that the dual functional finish surgical gown allowed heat to be transferred from the skin of subject to the atmosphere better than untreated. The nonwoven surgical gown showed no difference in comfort properties from cotton one.
The purpose of this study was to investigate the effects of an air mattress upon sleep and bed climate. This air mattress, which employs a pump and timer to increase or decrease the inflation pressure in order to cure and prevent decubitus was tested. Six healthy female volunteers, aged 18 to 23, served as subjects. The experiments were carried out under three conditions: using regular Futon (Futon), the air mattress with pump and timer activated (Air+) and the same mattress without pump and timer activated (Air-). Room temperature and relative humidity were controlled at 22-23°C and RH 50-60% respectively. Subjects' sleep was monitored by using EEG machine throughout the night, and subject's body temperature and bed climate were also continuously checked. Subjective estimation of bed and sleep were obtained before and after the recording sessions. Sleep onset latency and wake after sleep onset tended to be reduced in Air+ compared to Futon and Air-. The time and percentage of Stage 3 was increased significantly in the middle one third of the night in Air+. A significant difference was observed in bed climate of the waist area. Temperature tended to be higher in Futon than in Air+ and Air-, while relative and absolute humidity were significantly higher in Air+ and Air-. Significant difference between Air+ and Air- was observed only during one hour after sleep recordings started. Thermal sensation in the morning was cooler and comfort sensation tended to be better in Air+ and Air-. Subjective sleep estimation was somewhat good under all conditions. These results suggest that although these air mattresses do not affect sleep, we have to be cautious in using these mattresses as relative and absolute humidity were kept higher than with Futon. Further study on materials and construction of these air mattresses to decrease the humidity is needed.
Following the previous studies on the influence of light with different wavelengths on human biological rhythms during nighttime, present experiments were conducted to investigate the influence of morning light on the behavior of the core temperature and melatonin in humans. The experiments were carried out in four subjects with normal color vision. The subjects were exposed between 4:00 h to 9:00 h to red, green and blue light of 1, 000 lux and 2, 500 lux, and with an incandescent light of 50 lux as control. The main results were as follows: No differences in the behavior of core temperature and melatonin were found under the influences of red, green and blue light of 1, 000 lux and the control light of 50 lux. On the other hand, a tendency to promote the increase of core temperature and the fall of melatonin secretion was found after exposure to green light of 2, 500 lux, compared with control and red light. These results indicate that the behavior of core temperature and melatonin differs according to the wavelength of light, and that the phenomenon arises with morning as well as nocturnal irradiation. However, the intensity of light required to bring about the phenomenon seems to be different between morning and evening; an irradiation of 1, 000 lux × 5h at night in the previous report, and one of 2, 500 lux × 5h in the morning in the present experiments, were found to be necessary for green light to cause the effects.
The prime purpose of a safety helmet is to protect against occupational hazards. However, thermal comfort is one important ergonomics requirement for a helmet to be accepted by its wearer. To design and manufacture a thermally comfortable helmet, a method for testing and evaluating the thermal properties is essential. Research has long focused on the evaluation of dry heat transfer (conduction, convection and radiation). Evaporative heat transfer was not much addressed. In order to analyze the wet heat transfer (evaporation) component, a sweating thermal head manikin has been used. In this study the method has been further improved by constructing a new sweating head manikin. The surface of the head manikin is divided into five zones which can provide more detailed information about the environmental effects on the heat transfer from the head when a helmet is worn. Water supply (simulated sweating) is also improved by use of an electronic pumping system which provides a steady and adjustable flow rate of water to the head manikin. Experiments were conducted within a climatic chamber with this improved method under different test conditions: the ambient temperature and the head manikin surface temperature are set at the same level: 34 ± 0.5°C; two levels of head surface wettedness: 0.44 and 1.0; two levels of ambient humidity: 30% and 60% ; and two levels of wind speed: 0.4 m/s and 1.0 m/s. Seven different helmets were used in the experiments. The results showed that the improved method revealed more detailed information about the evaporative heat transfer; it is easier to use and control; less error is involved with the measurement.
To clarify the effect of listening to music on the impression obtained from the landscape viewed from the car, a simulation experiment using video reproductions was conducted. The impression left by the landscapes and that of the music excerpts were measured by a semantic differential method. The impression of the landscapes is more pleasant when music excerpts are reproduced than when no music is presented. The pleasantness of the landscapes is the highest when relaxing music is being played. The impression of the landscapes is more powerful when music is present. In particular, agitated music has a strong effect to make the impression of the landscape more powerful. Music generally has an effect to ‘lighten’ the landscape impression. However, very heavy music makes the landscape much heavier. Musical tempo is an important factor to determine the impression of music and affects the impression of landscape.
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