Pattern orientation in finite domains without boundaries

We investigate the orientation of nonlinear stripe patterns in finite domains. Motivated by recent experiments, we introduce a control parameter drop from supercritical inside a domain to subcritical outside without boundary conditions at the domain border. As a result, stripes align perpendicular to shallow control parameter drops. For steeper drops, non-adiabatic effects lead to a surprising orientational transition to parallel stripes with respect to the borders. We demonstrate this effect in terms of the Brusselator model and generic amplitude equations

Sustainable Graphic Design in Ireland - Identifying and overcoming obstacles and misconceptions in practice

This is an analysis of environmental ethics in current graphic design practice in Ireland. It investigates the most common obstacles, challenges and misconceptions that are presently being cited by Irish designers for not practising sustainably. A mixed method approach of a survey and a series of semi-structured interviews, accompanied by a small scale case study of a best practice design studio led to the result that designers in Ireland are very interested in sustainability but certain obstacles hinder them from implementing sustainable solutions in their work practice. Recommendations are made based on the findings for methods to be explored that may help to resolve said obstacles, master the challenges and overcome misconceptions

Variability of radio and TeV emitting X-ray binary systems : The case of LS I +61°303

X-ray binaries contain a compact object, a black hole or a neutron star, and a normal companion star. An exclusive club of only ∼5 sources, also emits in radio and in gamma-rays. The nature of these gamma-ray binaries is strongly debated, microquasar scenarios as well as a millisecond pulsar scenario were suggested. LS I +61°303 is special even among these gamma-ray binaries, first, because it emits strongly in radio, showing periodic outbursts every ∼26.5 days and secondly because of its strong and also periodic high and very high energy emission. In this thesis, results are presented from the analysis of the variability of the radio flux density and morphology in LS I +61°303 and the connection between its variable radio and high energy emission in order to better understand the nature of this source. It is shown that earlier analysis could not have identified certain characteristics in high energy data due to the usage of too large time intervals of data. Furthermore, very high energy data from LS I +61°303 show a correlation with X-ray data reminiscent of blazars, i.e. a microblazar. This led to a re-examination of archived data from the Very Long Baseline Array (VLBA) of LS I +61°303 in search of more microblazar clues. With an improved data reduction the radio morphology shows two- and one-sided structures with fast switches and accompanied by changes in the position angle corroborating a microblazar scenario. Subsequently, a dense spectral coverage of the flare in LS I +61°303 was obtained with the Effelsberg 100m telescope, following the method used for blazar monitoring. The flare spectrum is flat, suggesting a steady jet, and is followed by several optically thin subflares, reminiscent of shocks. One of these shocks is possibly correlated with a flux rise seen in the gamma-ray regime with Fermi-LAT (Large Area Telescope)

Systematic extension of the Cahn-Hilliard model for motility-induced phase separation

We consider a continuum model for motility-induced phase separation (MIPS) of active Brownian particles [J. Chem. Phys. 142, 224149 (2015)]. Using a recently introduced perturbative analysis [Phys. Rev. E 98, 020604(R) (2018)], we show that this continuum model reduces to the classic Cahn-Hilliard (CH) model near the onset of MIPS. This makes MIPS another example of the so-called active phase separation. We further introduce a generalization of the perturbative analysis to the next higher order. This results in a generic higher order extension of the CH model for active phase separation. Our analysis establishes the mathematical link between the basic mean-field MIPS model on the one hand, and the leading order and extended CH models on the other hand. Comparing numerical simulations of the three models, we find that the leading order CH model agrees nearly perfectly with the full continuum model near the onset of MIPS. We also give estimates of the control parameter beyond which the higher order corrections become relevant and compare the extended CH model to recent phenomenological models.Comment: 10 pages, 5 figure

Snapshots of sequential polyphosphide rearrangement upon metallatetrylene addition

Insertion and functionalization of gallasilylenes [L$^{Ph}$Si–Ga(Cl)L$^{BDI}$] (L$^{Ph}$ = PhC(NtBu)$_{2}$; L$^{BDI}$ = [{2,6-iPr$_{2}$C$_{6}$H$_{3}$NCMe}$_{2}$CH]) into the cyclo-E$_{5}$ rings of [Cp*Fe(η$^{5}$-E$_{5}$)] (Cp* = η$^{5}$-C$_{5}$Me$_{5}$; E = P, As) are reported. Reactions of [Cp*Fe(η$^{5}$-E$_{5}$)] with gallasilylene result in E–E/Si–Ga bond cleavage and the insertion of the silylene in the cyclo-E$_{5}$ rings. [(L$^{Ph}$Si-Ga(Cl)L$^{BDI}$){(η$^{4}$-P$_{5}$)FeCp*}], in which the Si atom binds to the bent cyclo-P$_{5}$ ring, was identified as a reaction intermediate. The ring-expansion products are stable at room temperature, while isomerization occurred at higher temperature, and the silylene moiety further migrates to the Fe atom, forming the corresponding ring-construction isomers. Furthermore, reaction of [Cp*Fe(η$^{5}$-As$_{5}$)] with the heavier gallagermylene [LL$^{Ph}$Ge–Ga(Cl)L$^{BDI}$B] was also investigated. All the isolated complexes represent rare examples of mixed group 13/14 iron polypnictogenides, which could only be synthesized by taking advantage of the cooperativity of the gallatetrylenes featuring low-valent Si(II) or Ge(II) and Lewis acidic Ga(III) units/entities

Klimawandel und Siedlungsstruktur: Anpassungspotenzial von Leitbildern und Konzepten

Das Arbeitspapier bewertet vor dem Hintergrund des Resilienzkonzeptes die Chancen und Potenziale von Siedlungsstrukturmodellen für die Klimaanpassung