Patent ID: 8335343

Claim:
A method for characterizing powder and granular material behavior in a rotating cylindrical container comprising: a) partially filling and closing a cylindrical container with transparent or semi-transparent ends with a known mass of a sample material consisting of a powder or granular material; b) orienting the cylindrical container so that it's length axis is in a horizontal position and then rotating it around its length axis at a known rotation speed causing the sample material to avalanche; c) acquiring a plurality of successive digital images of the sample material in the container using a camera with its optical axis within 45 degrees of the axis of rotation of the cylindrical container, a digital image being a matrix of pixels representing a two dimensional image of the sample material and cylindrical container with each pixel representing a physical height, physical width, and physical area of the sample material and cylindrical container; d) analyzing the digital images of the sample material and cylindrical container to determine a potential energy of the sample material in the cylindrical container for each image by : 1) determining a pixel height for each pixel representing the sample material relative to the bottom side of the cylindrical container by counting the number of pixels in the vertical direction from the bottom side edge of the cylindrical container to each pixel representing the sample material and multiplying by a scale factor equal to the physical height each pixel represents in the image; 2) calculating a pixel volume for the pixels making up the image by multiplying the length of the cylindrical container by a scale factor equal to the physical area each pixel represents in the image; 3) calculating a total volume of the sample material in the cylindrical container by summing all of the pixels representing the sample material and multiplying by the pixel volume; 4) calculating a pixel mass by multiplying the known mass of sample material in the cylindrical container by the the pixel volume and dividing by the total volume of the sample material in the cylindrical container; 5) summing all of the pixel heights for each pixel representing the sample material multiplied by the pixel mass multiplied by standard gravity on the earth, otherwise known as the standard acceleration due to free fall and equal to approximately 9.8 meters per second squared.