The small-deformation limit in elasticity and elastoplasticity in the presence of cracks

Der Grenzwert kleiner Deformationen in Anwesenheit eines gegebenen Risses wird in drei verschiedenen kontinuumsmechanischen Modellen betrachtet. Erstens wird für rein statische Elastizität mit finiter Spannung im Grenzwert kleiner Belastung bewiesen, dass die Nebenbedingung globaler Injektivität im Sinne der Gamma-Konvergenz eine lokale Nichtdurchdringungsbedingung auf dem Riss ergibt. Zweitens wird Deformationsplastizität mit finiten Spannungen und multiplikativer Zerlegung des Spannungstensors behandelt und die Gamma-Konvergenz zu linearisierter Deformationsplastizität mit Rissbedingungen gezeigt. Drittens wird die ratenunabhängige Evolution der Elastoplastizität betrachtet mit einer allgemeineren Klasse globaler Injektivitätsbedingungen für den finiten Fall. Hierbei wird einerseits die evolutionäre Gamma-Konvergenz unter Vernachlässigung der Nebenbedinung gezeigt, andererseits eine Vermutung aufgestellt, unter deren Voraussetzung die evolutionäre Gamma-Konvergenz auch mit Rissbedingungen gilt.The small-deformation limit in presence of a given crack is considered in three distinct continuummechanical models. First, a purely static finite-strain elasticity model is considered in the limit of small loading, where the constraint of global injectivity is shown to converge in the sense of Gamma-convergence to a local constraint of non-interpenetration along the crack. Second, finitestrain deformation plasticity based on the multiplicative decomposition of the strain tensor is shown to Gamma-converge to linearized deformation elastoplasticity with crack conditions. Third, the rate-independent evolution of elastoplasticity is considered with a generalized class of global injectivity constraints for the finite-strain model. On the one hand, neglecting the constraints the evolutionary Gamma-converge to linearized elastoplasticity is proven. On the other hand, a conjecture is made, subject to which the evolutionary Gamma-convergence with constraints still holds

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license

Linearized elasticity as Mosco-limit of finite elasticity in the presence of cracks

The small-deformation limit of finite elasticity is considered in presence of a given crack. The rescaled finite energies with the constraint of global injectivity are shown to Γ-converge to the linearized elastic energy with a local constraint of non-interpenetration along the crack

What drives relocation policies in the Maldives?

The predominant responses to rising sea levels are in situ adaptations. However, increasing rates of sea-level rise will render ex situ adaptations—in the form of relocations—inevitable in some low-lying coastal zones. Particularly small island states like the Maldives face this significant adaptation challenge. Here, government action is necessary to move vulnerable communities out of flood-prone areas. Yet, little empirical knowledge exists about the governance of relocations. While the literature often highlights risks and benefits of relocations, it remains unclear how governments organized relocations and what drove relocation policy. Therefore, we examined Maldivian relocation policies from 1968 to 2018 to explain government support of relocations. For this, we used a qualitative research design and extended the multiple streams approach with the theoretical lens of historical institutionalism. To gather data, we conducted semi-structured interviews (n = 23) with relocation policy experts and locals affected by relocations. Interview data was complemented with a desk review of relevant laws, historical records, and policy documents. We find 29 completed and 25 failed cases of relocations in the 50-year period. Key drivers of relocation policies are focusing events, socioeconomic development, and institutionalized island autonomy. We find that relocations were predominantly initiated as means to facilitate economic development, not as a response to rising seas or coastal risk. With current rapid economic development and strengthened democratic institutions, relocations are not considered as a policy option anymore. We conclude that implementing relocations proactively will face significant barriers in the future, which highlights the urgency of successful in situ adaptations in the Maldives.Peer Reviewe

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license

Linearized elasticity as Mosco-limit of finite elasticity in the presence of cracks

The small-deformation limit of finite elasticity is considered in presence of a given crack. The rescaled finite energies with the constraint of global injectivity are shown to Gamma converge to the linearized elastic energy with a local constraint of noninterpenetrability along the crack

The irrelevance of phonetics : the Polish palatalisation of velars

On accorde d'ordinaire un rôle important à la phonétique dans la description et l'explication phonologiques, en synchronie comme en diachronie. Le présent article met en doute la pertinence de ces facteurs. La palatalisation des consonnes vélaires en polonais remonte au 16ème siècle et s'observe devant voyelle antérieure. Son résultat moderne sont des alternances entre [k, g, x] et [c, ɟ, ç], alternances qui produisent également une distribution sérieusement restreinte de la seconde série de consonnes. En s'appuyant sur des faits synchroniques, diachroniques et dialectaux, l'auteur montre qu'il n'existe aucun lien de cause à effet entre le changement et son contexte. Les analyses antérieures sont basées sur un examen incomplet des données et un enracinement fort dans l'approche phonéticienne qui fait crédit au conditionnement phonétique des régularités phonologiques. Si l'on apprécie l'ensemble des données pertinentes qui sont à notre disposition, la supposée naturalité du processus qui palatalise des consonnes vélaires devant de voyelle antérieure s'avère relever de l'illusion. La conclusion provisoire est que tout conditionnement phonétique qui se veut linguistiquement pertinent doit être phonologiquement fondé.The paper challenges the generally accepted belief in the role of phonetics in phonological description and explanation, both with reference to synchrony and diachrony. The palatalisation of the Polish velar consonants, a historical innovation going back to the 16th century and applying before front vowels, has resulted in synchronic alternations of [k, g, x] with [c, ɟ, ç] and in serious restrictions in the distribution of the latter group of consonants. Synchronic, diachronic and dialectal evidence is gathered to show that no causal link can be established between the change and the context. The past claims are shown to have been based on incomplete or selective analysis of the data and a strong belief in the phonetic conditioning of phonological regularities. Once the totality of relevant facts is taken into account, the original assumption as to the naturalness of a process palatalising velars before front vowels turns out to be illusory. It is tentatively concluded that phonetics, to be significant, must be phonologically grounded

Midterm results of endovascular stent graft treatment for descending aortic aneurysms including high-risk patients

Methods: 21 patients (17 men, 4 women; mean age 66.1 years, range 29-90 years) with 15 true aneurysms, and 6 type B-dissections were treated by implantation of a TalentTM Endoluminal Stentgraft System from February 2000 to July 2003. In 3 cases it was necessary to overstent the left subclavian artery, in 1 case to overstent the left common carotid

The irrelevance of phonetics : the Polish palatalisation of velars

On accorde d'ordinaire un rôle important à la phonétique dans la description et l'explication phonologiques, en synchronie comme en diachronie. Le présent article met en doute la pertinence de ces facteurs. La palatalisation des consonnes vélaires en polonais remonte au 16ème siècle et s'observe devant voyelle antérieure. Son résultat moderne sont des alternances entre [k, g, x] et [c, ɟ, ç], alternances qui produisent également une distribution sérieusement restreinte de la seconde série de consonnes. En s'appuyant sur des faits synchroniques, diachroniques et dialectaux, l'auteur montre qu'il n'existe aucun lien de cause à effet entre le changement et son contexte. Les analyses antérieures sont basées sur un examen incomplet des données et un enracinement fort dans l'approche phonéticienne qui fait crédit au conditionnement phonétique des régularités phonologiques. Si l'on apprécie l'ensemble des données pertinentes qui sont à notre disposition, la supposée naturalité du processus qui palatalise des consonnes vélaires devant de voyelle antérieure s'avère relever de l'illusion. La conclusion provisoire est que tout conditionnement phonétique qui se veut linguistiquement pertinent doit être phonologiquement fondé.The paper challenges the generally accepted belief in the role of phonetics in phonological description and explanation, both with reference to synchrony and diachrony. The palatalisation of the Polish velar consonants, a historical innovation going back to the 16th century and applying before front vowels, has resulted in synchronic alternations of [k, g, x] with [c, ɟ, ç] and in serious restrictions in the distribution of the latter group of consonants. Synchronic, diachronic and dialectal evidence is gathered to show that no causal link can be established between the change and the context. The past claims are shown to have been based on incomplete or selective analysis of the data and a strong belief in the phonetic conditioning of phonological regularities. Once the totality of relevant facts is taken into account, the original assumption as to the naturalness of a process palatalising velars before front vowels turns out to be illusory. It is tentatively concluded that phonetics, to be significant, must be phonologically grounded