Effects of dietary n-3 polyunsaturated fatty acids and ... - FINS

1 st WorkshopXIII International Feed Technology Symposiumdepth of measuring room xzpixel f (x,y)I 0IycameraI 0Ireflexionwalllampbulk dropping,material with extinction coefficient εPCFigure 2. Schematic build-up and system components of the developed measurementsystem for measuring the dust concentrations in dust-air cloudsThe knowledge that a standard photo consists of 256 grey-value levels was used forevaluating the photo captures. The change of grey-value levels by a dispersed materialamount is equivalent to the light attenuation or the opacity respectively. By means of thismeasured variable and by knowing the material specific extinction coefficients, theconcentration of a dispersed material can be determined by the Lambert-Beer law.After the measurement system was calibrated and the basic operativeness could bedocumented in the relevant application range under pilot conditions, measurements ondiffuse dust concentrations were done at a grain bulk chute for side-dump trucks. Thebulk chute had a dust barrier. Dust-separation equipment was not available, however,there was a natural exchange of air. When recording the measured values, precleanedwheat was delivered. The current general risk assessment emanates from a distinctminimisation of the dust releases and explosion hazard if grain is available in precleanedform. This general hazard assessment shall be verified by the measurements.The concentration profiles of the whole dropping process are illustrated in the followingFigure 3 as an example for four of totally eight measuring points.18