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from the besides-letting-someone-shoot-you dept.
The testing of soft body armor has been a big concern because the deployment of a new kind of fiber—believed to be superior to the previous material—unexpectedly failed in 2003, resulting in the death of a police officer. That and other incidents prompted a 2005 recall of some of the vests made with the new material.
Although the performance of these vests was superior when they were fresh out of the box and in pristine condition, tests later showed that the mechanical properties of the fibers inside the vests began to deteriorate after a few months of normal wear. The new vests were eventually removed from market entirely and the manufacturer was sued by the Department of Justice (DOJ).
[...] The positron annihilation lifetime spectroscopy (PALS) technique provides a molecular-level view of the structure of materials. It has been used for testing materials in other sectors, including porous membranes and semiconductor insulators. For this work, positrons were injected into ballistic fibers and enabled researchers to determine if any voids were created during folding on a scale of less than 5 nanometers.
Using PALS, Holmes and Soles discovered that void levels are very sensitive indicators of damage sustained by the fibers after folding; a larger population of voids means a better chance of fiber failure. The team previously suspected that void creation was a critical component of mechanical degradation, but the small angle X-ray scattering measurements that had been used in the past tended to be less sensitive to voids smaller than 5 nanometers and proved to be inconclusive. The critical damage was occurring on much finer length scales.
Until better materials are developed, do not fold, spindle, or mutilate your bulletproof vest.
(Score: 2) by Runaway1956 on Wednesday October 18 2017, @02:20AM (4 children)
Silencers. Guy at work was eyeballing my 4 D-cell flashlight, for use as a suppressor. Told him to keep his eyes off of my tools, then asked him why he needed a suppressor. Seems he missed a deer, and blames it on excess noise from the muzzle blast. FFS - if you take your time, and get your shot right, there's no need for a second shot. No way can you blame a miss on the noise - your bullet either hit or missed BEFORE the blast ever arrived at the target.
Yeah, this is one of those ammosexuals that some of you Soylentils like to make fun of. If you ask them, they need more of everything, except target practice and discipline.
(Score: 0) by Anonymous Coward on Wednesday October 18 2017, @02:22AM
Does he like gladiator movies? Huh, Jimmy?
(Score: 1) by khallow on Wednesday October 18 2017, @04:58AM
I bet it was black.
(Score: 3, Interesting) by RamiK on Wednesday October 18 2017, @08:02AM
Playing devils advocate, training and maintaining your marksmanship takes a lot of time and money compared to using a suppressor. And even when you're top shape that first cold shot can cost you the whole day...
compiling...
(Score: 2) by Fnord666 on Wednesday October 18 2017, @12:40PM
He needs the suppressor because he needs a lot more range time so he doesn't miss his shot. Unsuppressed weapons can get quite loud, even through hearing protection on an enclosed or semi-enclosed range.