RESUMO
We draw attention to recent high-explosive (HE) experiments which provide compression of macroscopic amount of matter to high, even record, values of pressure in comparison with other HE experiments. The observed bounce after the compression corresponds to processes in core-collapse supernova explosions after neutrino trapping. Conditions provided in the experiments resemble those in core-collapse supernovae, permitting their use for laboratory astrophysics. A unique feature of the experiments is compression at low entropy. The values of specific entropy are close to those obtained in numerical simulations during the process of collapse in supernova explosions, and much lower than those obtained at laser ignition facilities, another type of high-compression experiment. Both in supernovae and HE experiments the bounce occurs at low entropy, so the HE experiments provide a new platform to realize some supernova collapse effects in laboratory, especially to study hydrodynamics of collapsing flows and the bounce. Due to the good resolution of diagnostics in the compression of macroscopic amounts of material with essential effects of nonideal plasma in EOS, and observed development of 3D instabilities, these experiments may serve as a useful benchmark for astrophysical hydrodynamic codes.
RESUMO
Volume model of transtrochanteric fracture of the femoral bone fixed by Targon PF dynamic fixator was studied by the finite element analysis. The following parameters were measured: magnitude and direction of displacement of system elements, pressure between fragments, and von Mises stress distribution in the fixator depending on support screw plunging into the sleeve. The results indicate that stability of the bone-nail system increases during fracture union and 10-mm shortening of the femoral neck axis, which is seen from a decrease in system deformation under load by 16.8%, stress in the implant by 20.2%, and pressure in the zone of fragments contact by 19.8%.
