INFLUENCE OF RADIATION CONDITIONS ON CRACKING OF COMPOSITE SCINTILLATORS

The article analyzes two main hypotheses describing the cracking of a composite scintillator in the irradiation zone. This is the "temperature" and "radiation-chemical" hypothesis of cracking. The analysis is based on experi-mental data that we obtained by irradiating scintillators and the results of model chemical experiments.

INFLUENCE OF RADIATION CONDITIONS ON CRACKING OF COMPOSITE SCINTILLATORS

The article analyzes two main hypotheses describing the cracking of a composite scintillator in the irradiation zone. This is the "temperature" and "radiation-chemical" hypothesis of cracking. The analysis is based on experi-mental data that we obtained by irradiating scintillators and the results of model chemical experiments.

Theoretical description of large deformations in criss-cross composites (with application to Tensylon®)

A theoretical model of an anisotropic material, Tensylon®, under large strains is proposed. This model is capable to describe the material’s response in in-plane tension at different angles to the fibrils. At 0° and at 90°, i.e., along the fibrils in either “criss” or “cross” plies, it quantitatively predicts the experimentally observed elastic behaviour until failure. At 45° to the fibrils, it quantitatively describes the experi- mental data in the elastic and plastic domains. The description remains accurate up to strains of 35%, that corresponds to 30÷40% of deforma- tion gradient components. The infinitesimal strains model would give at least 25% of error under such circumstances.

NOTIZEN. The Conformations of Oxacyclooctanes

The geometries and energies of the conformers of oxocane, the isomeric di-and trioxocanes, and of 1,3,5,7-tetroxocane were calculated by molecular mechanics. A boat-chair conformation was preferred by all molecules. From the preference of oxygen in the boat-chair conformations of oxocane (position 3 over 1 over 4) the preferred boat-chair form of all other oxocanes can be derived. The results are compared to experi-mental data, which in part can be reinterpreted. Additional CNDO/2 and MINDO/3 calculations were performed for 1,3,5,7-tetroxocane.