The shape of core-stones remained in the weathering basalt column is an index to classify its weathered degree. In this paper, a roundness index (RI) like the box dimension using in fractal theory, was employed to quantitatively measure the shape of core-stone in various weathering grades. The rounded core-stone that is weathered seriously has a smaller RI value. According to the value of RI, the five classes shown in the Russell-Taylor-Pettijohn chart for visually classifying grain shape is available to approximately determine the weathered grades of core-stones remained in the basalt column in Taiwan. A slump test is preliminarily tested to show the difference in repose angle of a stability slope assembled by the grains in a similar shape. The collection of angular core-stones those are less weathered (with a higher RI value) indeed reveals a greater repose angle.

Carbon nanotube backlight units (CNT-BLUs) offer advantages (including light weight and superior color performance) that cold cathode fluorescent lamp backlight units (CCFL-BLUs) cannot deliver. If these advantages find favor with liquid crystal display manufacturers, CNT-BLUs could possibly replace CCFL-BLUs. CNT-BLU light-emitting arrays are made by a thick-film screen printing process, which can leave dark obstructions within and between pixel areas. Thus, when the pixels light up, CNT-BLU arrays can display dark blotches within one or more pixels. Existing luminance uniformity measurements, such as Video Electronics Standards Association (VESA) or International Organization for Standardization (ISO) standards, are not designed to deal with this problem. These standards are based on the luminance of multiple non-adjacent points on a display; they cannot reflect the luminance change of adjacent pixels, which is important for measuring the uniformity of CNT-BLU. This situation is aggravated since CNT-BLU is still under development and the current luminance uniformity of CNT-BLU still cannot compete with that of CCFL. This study presents a new luminance uniformity measurement, line non-uniformity, for CNT-BLU. This method was compared with VESA and U Formula with respect to human perception. A set of CNT-BLU images with different levels of mottling was presented to 18 participants. The subjective acceptance thresholds for these images were then calculated. The uniformities using VESA, U Formula, and line non-uniformity approaches for these images were also calculated and fitted to the subjective acceptance threshold. The results showed that line non-uniformity was the best to fit the acceptance threshold; its R 2 ranged from 0.80 to 0.92 whereas the R 2 values of VESA and U Formula ranged from 0.00 to 0.49.