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High-speed video of single frozen water droplets impacting a surface was acquired. The frozen particles had a diameter ranging from 0.4 mm to 0.9 mm and impacted at velocities varying from 140 m/sec to 309 m/sec. The technique used to freeze the droplets and launch the particles against a surface is described in this paper. High-speed video was used to quantify the ice accretion area to the surface for varying impact angles (30⁰, 45⁰, 60⁰), and impacting velocities. An oxygen /acetylene cross-flow flame used to partially melt the traveling frozen particles is also discussed. A linear relationship between impact angle and ice accretion is identified for fully frozen particles. The slope of the relationship is affected by impact speed. Higher impact angles closer to perpendicularity between the surface and the particle trajectory, e.g. 60⁰, exhibited small differences in ice accretion with varying velocities. Increasing velocity from 161 m/sec to 259 m/sec nearly doubled the ice accretion area at a shallower impact angle of 30⁰. The increase accretion area highlights the importance of impact angle and velocity on the accretion process of partially melted ice crystals. It was experimentally observed that partial melting was not a pre-requisite for accretion at the tested velocities when impact angles of 45⁰ and 30⁰ were used. Partially melted droplets using just 0.0023 Joules of energy also doubled the ice accretion area. The partially melted state of the particles and a method to quantify the percentage increase in the ice accretion area is also described in the paper.

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The phenomenon of burning cone drop is a serious quality defect in super slim cigarettes. In order to monitor the burning cone drop, a segmentation model conveniently and effectively about cigarette packing density was established and used for predicting the burning cone drop rate. The method is a non-destructive testing (NDT), which is applied by using cigarette density and its change rate. The model of cigarette density segmentation method is based on a straight line ρ=A×ρ’+B in the Cartesian coordinate system with abscissa ρ′ and ordinate ρ. The straight line split the coordinate system into two regions. By measuring the density of the super slim cigarettes, the position of the point (ρ’, ρ) can be determined, then the burning cone drop tendency can be predicted. When verifying the accuracy of the model, it is found that the predicted value and the measured value are basically near the 1:1 line, the coefficient of determination (R2) and the index of agreement (D index) between predicted and observed values are 0.98 and 0.99 respectively, and the normalized root mean square error (nRMSE) is 11.8%. The coefficient of variation of the predicted burning cone drop rate is 6.5% for 10 consecutive replicates. The cigarette density segmentation method model is suitable for predicting burning cone drop of the super slim cigarette samples with varying packing densities or cut tobacco distribution. The model has a good effect on the burning cone drop prediction under certain conditions, and it has an important guiding significance for super slim cigarette production and quality inspection.