Understanding how high energy materials explode on a molecular level is extremely challenging. Everything happens so fast, on a small scale and with a variety of chemical and physical processes playing a part. New simulations modeled Nitramine RDX, found in many military explosives. The simulations show how shock waves cause primary chemical reactions, creating further mechanical stresses and more complex chemical reactions. Importantly, this work shows that computer simulations are now capable of examining the complex processes of explosions from first principles - information that is vital in the development of safe and effective explosives.
Journal article: http://link.aps.org/abstract/PRL/v91/e098301
2) Crackle sounds in the lungs
A. Alencar, et al.
Physical Review E (Published online: July 21, 2003)
Crackle sounds have long been used as a qualitative diagnostic tool for certain pulmonary dysfunctions. However, analysis of lung crackle sounds has not had a solid theoretical basis. A new model of crackle sounds accurately predicts what sounds are heard as airways open and close during breathing. The work may have clinical application because various lung diseases change the anatomical and physiological features that cause the crackle sounds.
Journal article: http://link.aps.org/abstract/PRE/v68/e011909
3) Anatomy of a bathtub vortex
A. Andersen, et al.
Physical Review Letters (Published online: September 5, 2003)
Although the vortex that drains a bathtub is the best-known vortex, it has been the focus of surprisingly little research. The few previous studies have made unrealistic assumptions in their models. A new analysis is
Contact: David Harris
American Physical Society