Suppose that water towers like those shown in Figure 1 are initially filled with water and have the same volume, height, and cross-sectional outlet area. Which one empties first? This problem arises naturally when designing watersupplying tanks or funnels. We find a formula expressing the emptying time as a function of the volume of liquid and its initial height. We compute the emptying time fo...

Abstract The damage effect of PTFE/Al/W reactive fragment impacting partially-filled fuel tank is investigated by combining the ballistic gun experiment and theoretical analysis. experimental results show that, with impact velocity ranging from 806m/s to 1331m/s, fragments successfully perforate front plate cause flash-ignition fuel/air mixture, but does not fail obviously. Based on results, a ...

INTRODUCTION E-cigarettes can be categorized into two basic types, (1) cigalikes, that are disposable or use pre-filled cartridges and (2) tanks, that can be refilled with liquids. The aims of this study were to examine: (1) predictors of using the two e-cigarette types, and (2) the association between type used, frequency of use (daily vs. non-daily vs. no use), and quitting. METHODS Online ...