für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

The effect of helium in iron is an important issue in nuclear systems, as iron and iron alloys (steels) are the primary materials used for structural elements. Helium is known to cause embrittlement and decrease fatigue life, as well as aid creep and promote swelling. These effects can significantly alter the mechanical properties of the reactor materials, and generally lead to early failure an...

This paper is the first of a two-part series dealing with quantum-mechanical (density-functional-based) studies of helium-mediated deposition of catalytic species on the rutile TiO(2)(110)-(1×1) surface. The interaction of helium with the TiO(2)(110)-(1×1) surface is first evaluated using the Perdew-Burke-Ernzerhof functional at a numerical grid dense enough to build an analytical three-dimensi...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Juho Rysti Name of the doctoral dissertation Microscopic and Macroscopic Studies of Liquid and Solid Helium Mixtures Publisher School of Science Unit O.V. Lounasmaa Laboratory Series Aalto University publication series DOCTORAL DISSERTATIONS 110/2013 Field of research Engineering Physics, Physics Manuscript submitted 16 April ...

A time-dependent neutronics analysis for the HIBALL reactor is presented. The helium to dpa ratio in the ferritic steel structure is found to be sensitive to neutron spectrum softening. The microstructure calculations show that helium diffusivity is a sensitive function of vacancy accumulation from one pulse to the next. A strong coupling exists between the three components of damage: helium, v...

The substitution of helium for nitrogen in the inspired air has been advocated for two entirely different reasons. First, Sayers and Yant (1926) suggested that owing to the low solubility of helium its use in diving and other operations involving respiration under high pressure might reduce the incidence of caisson disease. Secondly, Barach (1934) suggested that the lesser mass of the helium mo...

A method is described for investigating the ionization produced in helium by collisions between quasi-stationary atoms—that is, atoms possessing only thermal velocities—and a beam of neutral helium atoms with kinetic energy less than 100 eV. Ionization is shown to begin when the kinetic energy of the bombarding atoms is twice as great as the minimum kinetic energy which electrons must possess i...