University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

Mastersymmetries and Multi-Hamiltonian Formulations for Some Integrable Lattice Systems

Abstract: On obtient des quantites conservees, une formulation bi-hamiltonienne, une structure recursive et des symetries hereditaires pour un nombre de systemes reticulaires ayant une signification physique. On donne, pour les solutions multisolitons, des variables d'angle. A part le reseau de Toda bien etudie, ces systemes incluent: un reseau de Volterra, un systeme Network concentre, un reseau de Kac-Moerbeke-Langmuir et une classe d'equations de Network. On n'utilise pas la representation de Lax ou toute autre information additionnelle concernant les equations etudiees. Toutes les quantites sont trouvees d'une maniere purement algorithmique en utilisant les symetries maitresses

Frustrated Lewis Pair Catalyzed Dehydrogenative Oxidation of Indolines and Other Heterocycles

Abstract: An acceptorless dehydrogenation of heterocycles catalyzed by frustrated Lewis pairs (FLPs) was developed. Oxidation with concomitant liberation of molecular hydrogen proceeded in high to excellent yields for N-protected indolines as well as four other substrate classes. The mechanism of this unprecedented FLP-catalyzed reaction was investigated by mechanistic studies, characterization of reaction intermediates by NMR spectroscopy and X-ray crystal analysis, and by quantum-mechanical calculations. Hydrogen liberation from the ammonium hydridoborate intermediate is the rate-determining step of the oxidation. The addition of a weaker Lewis acid as a hydride shuttle increased the reaction rate by a factor of 2.28 through a second catalytic cycle.

Participation Trends of Ultra Endurance Events.

Abstract: Ultra endurance events are defined as sporting activities lasting >6 hours and include events such as ultramarathon foot races, ultra triathlons, ultra distance swimming, ultra cycling, and cross-country skiing. Popularity in these events has risen especially over the last 25 years with increasing participation notably in ultramarathon races where an exponential increase in participation has been observed. This is in large part due to the increasing popularity and participation of women and master athletes in these events. Other endurance sports have seen similar increases but overall numbers are much lower compared with ultramarathon events.

Detwinning in NiTi Alloys

Abstract: This work focuses on the stress-induced transformation in solutionized and overaged single-crystal NiTi alloys. The potential role of detwinning on the recoverable strains was investigated both theoretically and also with temperature-cycling experiments. The detwinning is the growth of one variant within a martensite in expense of the other. It is shown that the experimental recoverable strains in tension (near 8.01 pct in the [123], 9.34 pct in the [111], and 7.8 pct in the [011] orientations) exceed the theoretical martensite (correspondent-variant pair (CVP) formation strains (6.49 pct in [123], 5.9 pct in [111], and 5.41 pct in [011]), lending further support that partial detwinning of martensite has occurred in both the solutionized and overaged specimens. In compression, the experimental recoverable strains are lower than the theoretical martensite (CVP) formation strain. In the compression cases, the detwinning strain contribution is calculated to be negligible in most orientations. The transformation strains observed in overaged NiTi are similar to the solutionalized NiTi, suggesting that incoherent precipitates do not restrict the detwinning of the martensite. For the [123] orientation, it is demonstrated that the thermal hysteresis is higher in solutionized NiTi compared to the overaged NiTi. The higher thermal hysteresis can be exploited in applications involving damping and shape stability, while the lower hysteresis is suited for actuators.