The current study was performed to (1) understand the distribution of airborne fungi culturable on dichloran-glycerol agar (DG18) media over a oneyear monitoring period, (2) identify the types of airborne fungi collected, and (3) compare and contrast underand above-ground spaces, in two railway stations in Tokyo, Japan. Methods: Measurements of airborne fungi were taken at stations A and B located in Tokyo. Station A had under-and above-ground concourses and platforms whereas station B had spaces only above-ground. Airborne fungi at each measurement position were collected with an air sampler on DG18 media. After cultivation of the sample plates, the number of fungi colonies was counted on each agar plate. Results: In station A, the underground platform was characterized as (1) having the highest humidity and (2) a high concentration of airborne fungi, with (3) a high proportion of non-sporulating fungi (NSF) and Aspergillus versicolor. There was a strong positive correlation between the concentrations of airborne particles and fungi in station A. Common aspects of the two stations were (1) that fungi were mostly detected in autumn, and (2) there was no correlation between the humidity and concentration of fungi throughout the year. Conclusions: The results of this study indicate that the distribution and composition of fungi differ depending on the structure of the station.
There are many sound sources, for example trains, passenger and so on, and reflective materials are often used in large stations. So, many stations are noisy and reflective. To obtain the basic data for acoustical design in station, we measured sound level during operation and reverberation time and a distribution of sound pressure level at midnight without noise source in some stations. Next, we compared the results of these measurements and calculated value under diffuse sound field condition and used ray tracing method and so on. Finally, the relation between sound level and subjective evaluation was obtained by questionnaire survey.
Almost all commuter trains in Japan are equipped with cross-flow fans in order to circulate the air in a cabin and provide beneficial cooling to passengers, especially during the hot and humid summer seasons. The purpose of this study is to propose a method for predicting the passengers' thermal comfort in non-steady state thermal environments with airflow from cross-flow fans in commuter trains in summer. The proposed method is composed of two calculation parts: a part for calculating sensory temperature based on a human thermoregulation model applicable to non-steady state thermal environments, and a part for calculating the percentage of passengers dissatisfied with the thermal environment based on a statistical model derived from the results of experiments conducted in commuter trains in summer. In order to evaluate the thermal comfort with a cyclic wind from cross-flow fans, the proposed method converts the cyclic wind to a constant wind speed equal to the total amount of heat loss from the whole-body calculated by human thermoregulation model. Applying the proposed method to our previous research where fan-off/fan-on conditions and the congestion rates of below 100%, 120% and 180% had been performed, we examined the prediction accuracy of it. As a result, the mean absolute prediction errors of the proposed method in the congestion rates of below 100%, 120% and 180% under fan-off condition were 9.4pt, 8.2pt and 7.3pt, respectively, and those under fanon condition were 4.5pt, 10.0pt and 13.2pt, respectively.
In order to predict the level of vibration and structure-borne sound of a building near the underground railway tracks, it is essential to investigate vibration propagation from the ground to the foundation of the building. Therefore, the authors proposed a simple prediction method of vibration propagation from the ground to pile-foundations based on the dynamic-substructure method, which was able to consider the soil-structure-interaction. In the method, input vibration to pile-foundations and response ratio of upper-structures with the dynamic-soil-spring were calculated. We predicted the vibration propagation from the tunnel to the buildings of three types, and confirmed that the predicted results were similar to the measurements.
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