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In two test series, liquid and solid gold-based neutron flux monitor materials were investigated with respect to the effects of neutron absorbers such as chlorine, scattering effects, and the dependence of the enhanced activation caused by the epithermal resonance integral. The liquid monitors were prepared from aqueous solutions of tetraamminegold(III) nitrate and tetrachloroauric(III) acid. The presence of chlorine-35 partly suppresses the activation of gold-197; this effect depends not only on the concentration of the absorber but also on the state of the neutron flux density monitor. Aqueous samples show greater relative losses than solid monitors. Neutron scattering occurs in hydrogen-rich sample matrices which is shown by the fact that cadmium-shielded aqueous samples show an over proportional activation. Hence, fast neutrons must be moderated to the epithermal energies covered by the resonance integral, which is characterized by much greater cross sections for the capture of neutrons. The insight of this study with respect to neutron scattering in hydrogen-rich matrices must be taken into account also for neutron activation analysis; sample and standard must have a similar matrix with respect to its neutron scattering properties, otherwise the effect of increased activation as well as of enhanced selfshielding are underestimated.

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Loading parameters (frequency, amplitude ratio and waveform) are varied to determine their influence on fatigue crack growth in rubber. Up to three different rubber blends are investigated: one actual engineering material and two model materials. Fatigue crack growth curves and strain distributions of pure shear and faint waist pure shear samples are compared for a model material. Fatigue behavior is studied for three different frequencies (1 Hz, 3 Hz and 5 Hz). Amplitude ratio appears to be another important influence factor concerning fatigue crack growth in rubber. The beneficial effect of positive amplitude ratios (tensional loading conditions) is shown for different materials. However, fatigue crack growth is considerably increased for negative amplitude ratios (tensional-compressional loading conditions). Furthermore, the influence of the waveform is determined for three different waveform shapes. One is sinusoidal, and two have a square shape, including dwell periods and sinusoidal slopes. Special focus lies on heat build-up, which is substantial, especially for large loads, high frequencies and/or highly filled rubber blends. Plateau temperatures are determined for various loading conditions and rubber blends. A very simple linear relationship with dissipated energy per time and unit area is obtained. Results gathered with dynamic mechanical analyses show, likewise, a linear trend, but the heat build-up is very small, due to different sample geometries.