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Thermal Effects On Solar Radiated Sand SurfacesContaining Landmines — A Heat Transfer Analysis

1970; WIT Press; Volume: 20; Linguagem: Inglês

10.2495/ht980181

1746-4471

Stefan Sjökvist, Mikael Georgson Stefan Ringberg, Magnus Uppsäll, Dan Loyd,

Earthquake Detection and Analysis

This paper reports on the possibility of modelling thermal effects for detecting mines using infrared imaging systems. Results from experiments made in an indoor test landscape, using a sandbox and a solar panel with measuring instruments, are compared to simulated data from a heat transfer model. The radiation from the panel was varied in order to resemble the solar variation from sunrise to sunset. The different temperatures of the sand surface, the sand at different depths and on the surfaces of the four generic mines were sampled at one-minute intervals throughout the experiments. Infrared cameras working in the 2-5 p.m and 8-12 jam bands were used in order to record images of the sand surface. The camera system calculates the apparent temperature of selected areas of the images based on the detected radiation The simulation was carried out using the Finite Element Method. The sequences of the infrared images show the variation in emitted radiation as the irradiation of the surface is varied. There are two different phenomenon dominating the two wavelength bands In 2-5 p.m region there is a reflecting dominance and in the 8-12 p.m region the radiation originates mainly from emission. The simulation shows good agreement with the experimental result for the depth profile, where the temperatures were studied along a vertical line through the centre of the mine, as well as for the surface temperature