University students' health may be adversely affected by exposure to indoor bacterial contaminants on their campuses. This study aims (1) to quantify culturable bacterial concentrations in three indoor environments at a university, (2) to investigate the influence of meteorological factors and gender, to assess the relationship between indoor and outdoor, and (3) to estimate the bacterial dose for university students in different indoor environments. Airborne bacteria samples were collected in 12 classrooms, in 12 living rooms and four bathrooms in two dormitory buildings, and in a dining hall. The results showed that the microenvironment in the female dormitory had the highest mean bacterial concentration (2847 CFU/m 3 ), whereas the lowest mean bacterial concentration was observed in classrooms (162 CFU/m 3 ). Indoor bacterial concentrations in male dormitories were significantly lower than in female dormitories probably because of crowding and increased ventilation. Outdoor weather conditions were associated with the indoor concentrations with regard to insufficient ventilation and varying outdoor concentration. The occupants' activity level was also more closely related to the indoor bacteria concentration in the residential setting. Students experienced about four times higher dose of airborne bacteria in the dormitories than in the classrooms and dining hall.
Metal materials especially steel or cast iron are used extensively in many types of
construction such as buildings, bridges, cranes, vehicles and so on, so detection or prediction of metal failure is very important, but deformation of metal material often deliveries heat energy which can be detected by infrared imager. The test specimen is installed between the two grips of the testing machine and then loaded in tension and in compression. The IR913A infrared imager is used to observe the deformation of metal specimen. The high-sensitive infrared thermal images of metal specimen in the different phase of deformation are obtained. The paper theoretically analyzes the
reason from the thermodynamics and plastic mechanics, the conclusions are drawn as follows: 1) When applying loads, temperature field on the surface of metal specimen is changing, the local rise of temperature is remarkable, this can be observed from the infrared thermal images. 2) From the infrared thermal images, rising temperatures are found in the regions of stress concentrations. 3) When the test specimen approaches to failure or appears fracture, there is a remarkable change that can be shown from the infrared thermal images with remarkable colors.
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