Engineering transport by concatenated maps

We present a generalized kick rotor model in which the phase of the kick can vary from kick to kick. This additional freedom allows one to control the transport in phase space. For a specific choice of kick-to-kick phases, we predict novel forms of accelerator modes which are potentially of high relevance for future experimental studies

The sign of the reaction volume for the water/silica reaction

In the present report, we deal with the question whether the equilibrium of the silica/water reaction shifts under tensile stresses to an increased or reduced hydroxyl concentration or equivalently, which sign the reaction volume shows. From our analysis on the basis of the Le Chatelier-Braun Theorem, it can be concluded that the equilibrium constant of the watersilica reaction is enhanced due to tensile stresses and that the reaction volume change is positive. In additon it will be shown that the apparently found enlarged water solubility under compressive stresses by Nogami and Tomozawa [2] is an artifact of the stress-dependent diffusivity

Insulation for cryogenic tanks has reduced thickness and weight

Dual seal insulation, consisting of an inner layer of sealed-cell Mylar honeycomb core and an outer helium purge channel of fiber glass reinforced phenolic honeycomb core, is used as a thin, lightweight insulation for external surfaces of cryogenic-propellant tanks

Arthritis Is Developed in Borrelia-Primed And -Infected Mice Deficient of Interleukin-17

Interleukin-17 (IL-17) has been shown to participate in the development of Lyme arthritis in experimental mice. For example, neutralization of IL-17 with antibodies inhibits induction of arthritis in Borrelia-primed and -infected C57BL/6 wild-type mice. We hypothesized that mice lacking IL-17 would fail to develop Borrelia-induced arthritis. IL-17-deficient and wild-type C57BL/6 mice were primed with heat-inactivated Borrelia and then infected with viable spirochetes 3 weeks later. No swelling or major histopathological changes of the hind paws were detected in IL-17-deficient or wild-type mice that were primed with Borrelia or infected with viable spirochetes. By contrast, IL-17-deficient and wild-type mice that were primed and subsequently infected with heterologous Borrelia developed severe swelling and histopathological changes of the hind paws. In addition, Borrelia-primed and -infected IL-17-deficient mice exhibited elevated gamma-interferon (IFN-γ) levels in sera and increased frequencies of IFN-γ-expressing lymphocytes in popliteal lymph nodes compared to Borrelia-primed and -infected wild-type mice. These results demonstrate that IL-17 is not required for development of severe pathology in response to infection with Borrelia burgdorferi, but may contribute to disease through an interaction with IFN-γ

Hydroxyl Damage in Silica: Full-range description including large damages

When water diffuses into silica glass it reacts chemically with the glass forming nanometre sized pores that change the physical properties of the glass. In earlier papers and reports, we discussed the effect of water/silica reaction on the strength via volume swelling, and showed by use of damage mechanics that the water reaction reduces Young’s modulus E and intrinsic strength in thin surface layers. In this paper, the dependency between hydroxyl concentration and damage will be derived for the full damage range by using experimental results from literature. For small water concentrations, we used sound velocity measurements from literature. The suggested relations describe the dependence between the hydroxyl concentration and the Young’s modulus for the damaged glass and allow the strength decrease due to hydroxyl generation to be computed. From an example of application, it can be concluded that damage by hydroxyl generation has little effect on strength even in the case of completely damaged surface region so far the water-affected surface zone is much thinner than the bulk material

Stress-enhanced silica/water reaction under torsion loading

Water reacting with silica causes the generation of hydroxyl SiOH accompanied by a volume or swelling expansion. The principle of LeChatelier ensures that the hydroxyl concentration increases with increasing externally applied stresses. From the analysis in [1,2] it becomes obvious that a) the hydroxyl concentration must depend on the multi-axiality of the applied stresses, and b) that the swelling effect is anisotropic. On the basis of the results in [1,2] it will be shown that under torsion loading the strongest effects on stress-enhanced hydroxyl generation and swelling strains should occur, although this stress state shows a disappearing hydrostatic stress term