In this work, firstly, high-pressure air blasting experiment is conducted on concrete specimen with a size of 600 mm × 600 mm × 600 mm, the blasting crack distribution is observed and the particle vibration acceleration at the outer boundary of the sample is monitored.
The contact area between the loading block and the specimen can have the shape of the lateral geometric boundary of the sample (a curved (C) portion of the lateral surface of a right circular cylinder).
During the process of fall, the thermal target will cross the boundaries of the sampling cells and PIR sensors will generate output correspondingly.
As the body passes the boundaries of the sampling cells, the PIR sensors will generate output with different characteristics corresponding to different human motions, e.g., falling, sitting down, standing up from a chair, walking, and jogging.
When the fall occurs, the human body will cross the boundaries of the sampling cells, and output of the PIR sensors array will reflect the spatio-temporal characteristic of the action.
The PIR sensors with Fresnel lens array are essentially sensitive to thermal change, especially at the boundaries of the sampling cells, which are preferable in terms of sensing efficiency in the sense of reducing the number of sensors involved without degrading the sensing performance.
To prevent biases related to the boundary effect of the sampling units, only the corals with centers lying within the sampling unit were enumerated (following the "center rules" scheme of Zvuloni et al. [39]).
This is again done in order to average out the effect of the boundaries of the samples with air.
Transparent parts can be seen at the upper and lower sample boundaries, the edge of the sample column, and around the fractures with a width of ca. 200 μm.
Temperature (300 K-500 K) and frequency dependent dielectric properties and complex impedance analysis have been carried out to investigate the effect of grain and grain boundary of the synthesized sample.
