Using 3D printing to fabricate realistic test projectiles for natural fragmentation from buried charges.

Buried charges such as improvised explosive devices continue to be one of the most lethal and hidden threats service members face. On detonation, ground debris near the blast area is accelerated towards service members as secondary fragmentation, consisting of sand, gravel and rocks. In order to mitigate injury, protective equipment can be worn, yet it is difficult to gather accurate data for engineering decisions when the standard test uses a fragment simulating projectile made from metal. It is difficult to test secondary fragmentation from ground debris due to the natural heterogeneity and variance of the material. A methodical and reproducible method of testing fragmentation damage from ground debris was developed to study and improve protective equipment against natural secondary fragmentation. We present herein the novel process of 3D-printing ballistic projectiles from silica sand, followed by launching with an air canon. Outlined within are the successes, challenges and proposed implementations of the technology. The 3D-printed sand projectiles achieved speeds over 170 m/s, resulting in measurable damage to single Kevlar sheets. Other flight parameters such as yaw and rotation were captured, resulting in observations about design and shape of the projectiles. It was found that one design performed better in terms of velocity, rotation and impact. The technology has the potential to disrupt the protective equipment sector by providing a controlled means of assessing natural fragmentation damage.

G.B. Morgagni: the father and founder of contemporary pathology.

Giovanni Morgagni (1682-1771) who lived in the 18th century was the greatest pathologist that ever existed. His fame extended beyond his country, Italy, and his name became universally known, being the Father of Contemporary Pathology. He set the basis for the creation of a new medical specialisation, pathology, which was unknown at the time. His brilliant mind made a big step in the formation of a new type of clinical thought in every day medicine. He managed to make the clinician, physician and surgeon think and act in a different scientific manner; to think in an anatomo-clinical way. In other words, by correlating the symptoms of a certain disease with the corresponding pathological alterations, he also discovered many new diseases and wrote many books which were unique for their wisdom.