Visibility Measurement Using Digital Cameras in Qingdao

Abstract

Visibility is an important meteorological element which affects people's daily life in many fields, such as aviation, navigation and land transportation. An easy method to measure visibility was presented in this paper. Digital camera was adopted to get the images of a target which had a clear boundary between it and its background (such as the sky). Then the luminance ratio method was applied to obtain the visibility.To verify the feasibility of this method, image data were taken at 8:00, 11:00, 14:00 and 17:00 every day using a digital camera in Qingdao. The visibility values were compared with those announced by Qingdao Meteorological Bureau, and the deviations were acceptable. In view of the simplicity of this measurement method, it is promising in the future for application in real life.

Theoretical Calculation of the Strength of the Mass Concrete

“…Theory and the validation of the result The percentage of each age strength of concrete calculated by means of maturity theory are shown in table 1，because the data fc,m provided by Ref. [4] is a concrete strength value on average， in order to ensure the strength of concrete being with 95% reliability, so we consider fc,k=fc,m(1-1.645δ), k is the standard value of cube compressive strength, δ is the variation coefficient of concrete and equals 1.8. Defining the measured value of the percentage of concrete strength is 40…”