Cranfield Defence and Security, Cranfield University, Shrivenham, Swindon, Wilts SN6 8LA, UK.
Cranfield Defence and Security, Cranfield University, Shrivenham, Swindon, Wilts SN6 8LA, UK.
Forensic Sci Int. 2022 Jul;336:111317. doi: 10.1016/j.forsciint.2022.111317. Epub 2022 Apr 26.
The majority of fabrics at crime scenes have been coloured in some way. The effect of such treatments on resultant bloodstains has not been considered. In this work, horse blood was dropped onto reactively dyed calico fabrics (100% cotton, plain woven) with three different masses of 91 g m², 171 g m² and 243 g m² and the results compared to previous work on the not-coloured calico fabric. Five impact velocities were used from 1.7 ms to 5.4 ms. The use of reactive dye increased the thickness (from 0.38 - 0.56 mm to 0.39 - 0.6 mm) and mass per unit area (from 85.1 - 224.6 g/m² to 91 - 243 g/m²) of the calico fabrics. The reactively dyed fabrics had larger bloodstains (e.g. lightest calico 41.2 - 78.6 mm²) compares to the not-coloured fabrics (e.g. lightest calico 21.4 - 67.5 mm²) across all three mass per unit areas. The dyeing of the fabrics altered the intra-yarn spaces to a more optimum size for wicking blood, increasing the ease with which the blood could wick along the yarns in the dyed calico. The amount of wicking varied depending on individual variations within the fabrics and yarns. More variation in dry bloodstain area was seen among dyed calico specimens than for the not-coloured fabric. The amount of wicking which was seen on the dyed calico meant there was no correlation between dry bloodstain area and impact velocity, a correlation which was seen on the medium and heavy not-coloured calico in the previous work.
犯罪现场的大多数织物都经过了某种方式的染色。然而，这些处理方式对血液斑痕的影响尚未得到考虑。在这项工作中，马血被滴落在反应性染色的平纹棉白布（100%棉）上，布的质量分别为 91g/m²、171g/m²和 243g/m²，并将结果与之前对未染色平纹白布的研究进行了比较。使用了五个不同的冲击速度，从 1.7ms 到 5.4ms。使用反应性染料增加了平纹布的厚度（从 0.38-0.56mm 增加到 0.39-0.6mm）和单位面积的质量（从 85.1-224.6g/m²增加到 91-243g/m²）。与未染色的织物相比，反应性染色的织物上的血液斑痕更大（例如，最轻的平纹白布为 41.2-78.6mm²）。在所有三个单位面积质量的情况下，染色的织物改变了纱线之间的空间，使其更适合血液虹吸，从而增加了血液沿着染色平纹布的纱线虹吸的容易程度。虹吸的量取决于织物和纱线内部的个体差异。在染色平纹布的样本中，干燥血液斑痕面积的变化比未染色的织物更大。在染色平纹布上看到的虹吸量意味着，干燥血液斑痕面积与冲击速度之间没有相关性，而在之前的研究中，中等和较重的未染色平纹布之间存在这种相关性。
