Sphericity, a measure of how much a particle’s shape deviates from spherical, is useful as a shape factor when characterizing particulate materials. However, particle surface areas, required when determining the sphericity, are very difficult to measure. As a result, the circularity, derivable from microscopic views, is often measured instead and assumed to be equal to the sphericity. This paper shows that the two quantities are generally not equal for simple non-spherical shapes and provides advice on improving the estimation of sphericity from circularity.

中文翻译：

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连接粒子的球形度和圆度

当表征颗粒材料时，球形度是衡量颗粒形状偏离球形多少的度量，可用作形状因子。但是，确定球度时所需的颗粒表面积很难测量。结果，通常从微观视图得出的圆形度被代替地测量并且假定等于球形度。本文表明，对于简单的非球形形状，这两个量通常不相等，并为改进从圆形度估计球形度提供了建议。