Measurements and analysis of transmitted spectra from LOTUS fission-suppressed hybrid blanket driven by D-T neutrons

The neutron spectra transmitted across a fission-suppressed hybrid blanket and its components, driven by a low intensity 14 MeV Haefely neutron generator, were measured with a 2×2 NE213 detector at LOTUS facility. These experiments have been analyzed with 2D and 3D codes DOT3.5 and MCNP, respectively. The spectral integrals between 15 to 1 MeV show good agreement among the 2D, the 3D, and the NE213 for 15 cm lead, 18 cm beryllium, and 25 cm graphite slabs. However, there are large discrepancies for 6.2 cm stainless steel and 15 cm lithium carbonate slabs. The assemblies involving two or more of these slabs reflect these tendencies. We observe also considerable disagreement over pointwise spectra for a number of assemblies.Work done while on visiting assignment to Institut de Génie Atomique, E.P.F.L.     

Distribution of the number of jobs in a GI/GI/1/∞ queue with a constant flow time constraint

We derive the Laplace transform of the joint distribution density of the number of jobs and of the vector of their flow time in a GI/GI/1/ queue with a constant constraint on job flow time.Translated from Kibernetika, No. 1, pp. 78–81, January–February, 1889.     

Martensitic transformation in alloys of the system TiNi-TiCu prepared by ultrarapid melt cooling

Conclusion In alloys of the TiNi-TiCu system prepared in the form of thin tapes by ultrarapid melt cooling the B2-phase, which is unstable towards martensitic transformation B2B19, contains up to 35% Cu, whereas in bulk alloys prepared in the form of an ingot cooled at normal rates it contains about 10% Cu close to the M_S. In alloys containing up to 35% Cu there are no untransformed brittle phases preventing development of martensitic transformation throughout the volume of the material. The structure of alloys is quite uniform, particularly those obtained by crystallizing from the amorphous condition, and the grain size of the high-temperature phase is a fraction of a micron. The fine structure of alloys close to a globular at a high cooling rate. Thus, range of practically important alloys of the B2 type with inelastic behavior effects, e.g., the shape memory effect, is considerably expanded.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 38–41, November, 1988.     

Van der Pauw measurement of metal fibre orientation in a plastic-metal composite

Stainless steel fibres in ABS plastic form a composite with an anisotropic resistivity. Samples are rectangular shapes with uniform thickness. By assuming two principal resistivities and by using van der Pauw's technique, we find ² = _{x y} . For rectangular samples, field theory determines _y / _x and hence fibre direction. Results for three sample geometries agree with the theoretical predictions of the fibre patterns and with X-ray data. Samples formed by a centre-sprue feed are the best for fabricating large, uniform samples, while samples with a large length-to-width ratio have the most uniform metal density and fibre orientation. Resistivity was also measured by the more-common two-probe technique. Results correlate well to van der Pauw data, with 95% confidence.