Measurement of specific fracture energy and surface tension of brittle materials in powder form

V článku uvedeno Libor M. Hlaváč.This article presents a method for the experimental measurement of specific fracture energy and surface tension of a brittle materials in a powder form. This work is focused on testing a method on the mineral, almandine. A hydraulic press was used in the experiment to crush powder particles, and statistical evaluation was used to analyze the change in the powder surface. The powder was subject to various conditions during crushing. The crushing was performed both in air and in water. It was done at three different compression speeds, namely 15.8 MPa/s, 3.95 MPa/s and 2.25 MPa/s. The experimental results showed measurable differences in the specific fracture energy values in the presented regimes

Di-electron measurements in C+C reactions at 2 GeV.A with HADES

EIThe High Acceptance DiElectron Spectrometer HADES has been recently commissioned at GSI, Darmstadt. It has been designed for systematic studies of hadron properties inside nuclear matter. We report first preliminary results on invariant masses e+e--pairs which were measured in 12C + 12C collisions at Ekin=2 GeVdot operatorA. The analysis methods are briefly outlined and a comparison with detailed Monte-Carlo simulations is shown