Aix Marseille Université , CNRS, IUSTI, Marseille, France.
Langmuir. 2018 Jan 23;34(3):1143-1150. doi: 10.1021/acs.langmuir.7b02718. Epub 2017 Nov 7.
Bloodstain pattern analysis (BPA) is used on a daily basis as evidence in crime scene reconstruction. However, though the impact behavior of complex fluid droplets have been extensively studied, important questions still remain. We investigate the influence of surface roughness and wettability on the splashing limit of droplets of blood, a non-Newtonian colloidal fluid. Droplets of blood perpendicularly impacting different surfaces at different velocities were recorded with a high-speed camera. The recordings were analyzed as well as the surfaces characteristics in order to find an empirical solution because we found that roughness plays a major role in the threshold of the splashing/nonsplashing behavior of blood compared to the wettability. Moreover, it appears that roughness alters the deformation of the drip stains. These observations are key to characterizing features of drip stains with the impacting conditions, yielding a more complete forensic analysis in certain cases.
血迹形态分析（BPA）在犯罪现场重建中每天都被用作证据。然而，尽管复杂液滴的冲击行为已经得到了广泛的研究，但仍有一些重要的问题悬而未决。我们研究了表面粗糙度和润湿性对血液液滴飞溅极限的影响，血液是一种非牛顿胶体流体。高速摄像机记录了血液液滴以不同速度垂直撞击不同表面的情况。我们对记录进行了分析，并对表面特性进行了分析，以找到一个经验解决方案，因为我们发现与润湿性相比，粗糙度在血液的飞溅/不飞溅行为的阈值中起着重要作用。此外，似乎粗糙度改变了液滴痕迹的变形。这些观察结果对于根据冲击条件对液滴痕迹的特征进行分类至关重要，在某些情况下可以提供更完整的法医分析。
