Surface growth for molten silicon infiltration into carbon millimeter-sized channels: Lattice–Boltzmann simulations, experiments and models

The process of liquid silicon infiltration is investigated for channels with radii from 0.25 to 0.75 [mm] drilled in compact carbon preforms. The advantage of this setup is that the study of the phenomenon results to be simplified. For comparison purposes, attempts are made in order to work out a framework for evaluating the accuracy of simulations. The approach relies on dimensionless numbers involving the properties of the surface reaction. It turns out that complex hydrodynamic behavior derived from second Newton law can be made consistent with Lattice-Boltzmann simulations. The experiments give clear evidence that the growth of silicon carbide proceeds in two different stages and basic mechanisms are highlighted. Lattice-Boltzmann simulations prove to be an effective tool for the description of the growing phase. Namely, essential experimental constraints can be implemented. As a result, the existing models are useful to gain more insight on the process of reactive infiltration into porous media in the first stage of penetration, i.e. up to pore closure because of surface growth. A way allowing to implement the resistance from chemical reaction in Darcy law is also proposed.

Reaching for a Calculator or a Mirror? Why the EU Joins International Human Rights Treaties. EU Diplomacy Paper 01/2013

Why does the European Union (EU) join international human rights treaties? This paper develops motivational profiles pertaining either to a ‘logic of appropriateness’ or a ‘logic of consequentialism’ in order to answer this question. It compares the EU’s motivations for its recent accession to the United Nations Convention on the Rights of Persons with Disabilities (UNCRPD) with those dominating the EU’s nonaccession to the Council of Europe Convention on preventing and combating violence against women and domestic violence (Istanbul Convention). Based on this cross-case analysis, I argue that the EU’s accession decisions are best viewed as cost-benefit calculations and explained by the strength of opposition and the desire to spread its norms. The EU is only marginally concerned with efforts to construct an ‘appropriate role’, although its accession considerations are positively influenced by (varying degrees) of an internalized commitment to human rights. The paper aims at deepening the understanding of the EU’s motivations in the paradigmatic hard case of accession to international human rights treaties not least to evaluate the EU’s ‘exceptional nature’, facilitate its predictability for stake-holders and contribute to political and ethical debates surrounding future rites of passage as a global actor.

Brazilian perspectives on the changing global order and security challenges. CEPS Working Document No. 376, February 2013

This study analyses the current picture and prospects for EU–Brazil relations in the political and security arenas. As actors experiencing relevant changes, albeit in different directions in their respective international status quo, the EU and Brazil have found some common ground for convergence at the macro level on some structural issues, such as the normative framework of a changing global order, the striving for a multipolar world and the relevance and desirability of multilateralism. At the same time, it is argued that they differ significantly as to the strategies pursued in the attainment of those shared interests, resulting in competing, or eventually divergent, policy preferences when addressing specific issues and developments at the international level, limiting the prospects for a deep mutual commitment and engagement in political and security dynamics at the global level.

La modernisation de Tunis : un urbanisme et une architecture d’État au miroir d’une anthologie de la percée dans la médina (1881-1987)

Cette thèse traite de quelques moments clés dans l’histoire urbaine et architecturale moderne de la ville de Tunis. Elle les aborde conjointement à la problématique du percement de son noyau historique : la médina, née d’un projet de modernisation urbaine lancé par les beys de Tunis à la fin du XIXe siècle, poursuivi par le protectorat français de 1881 à 1956, puis par le gouvernement indépendant de 1956 à 1987. Partant, la recherche est répartie sur trois temps avec, au centre, le projet de la percée dite de la Casbah adopté par le Président Bourguiba à la fin de 1959. Pour plusieurs raisons, ce moment est cité rapidement dans la littérature malgré son importance dans la compréhension du visage actuel de la capitale tunisienne. Pour le saisir, on a dû retourner aux premières tentatives de percement de la médina de Tunis par le colonisateur français en 1887. Puis, on s’est progressivement approché de l’ancêtre direct de la percée bourguibienne paru sur le Plan directeur de Tunis en 1948. De ce premier temps, on a mis en valeur les stratégies coloniales dans leur gestion du territoire et leur rapport au processus de valorisation/dévalorisation du patrimoine issu de la civilisation arabo-islamique. Le second temps, qui correspond au plan de décolonisation mené par l’État indépendant dès 1955, est marqué par le lancement d’un « concours international ouvert pour une étude d’aménagement de la ville de Tunis » organisé par le Secrétariat d’État aux travaux publics en collaboration avec l’Union internationale des architectes. L’étude de cet événement et du colloque qui l’a suivi a ôté le voile sur ses raisons d’être politico-économiques que dissimulaient les usuels soucis de l’hygiène, de la circulation et de l’embellissement du Grand Tunis. Pour appuyer davantage ces constats, un troisième et dernier temps a été dédié au chantier de Tunis au lendemain du concours. L’accent mis sur les lieux symboliques du pouvoir et le désir obsessif des autorités à se les approprier ont réduit ce chantier à une redistribution concertée des symboles de la souveraineté nationale dans le but de centraliser et de personnifier le pouvoir en place. Le présent travail se situe dans le cadre des études postcoloniales et projette un regard critique sur la décolonisation en rapport avec ce qu’on a taxé d’urbanisme d’État. Propulsé par une certaine perception de la modernité, cet urbanisme est indissociable d’une instrumentalisation politique qui met l’accent sur les questions identitaires et patrimoniales, insiste sur la rupture avec le passé et tend à écarter l’opinion publique des questions inhérentes à l’aménagement du territoire et à la sauvegarde de la mémoire collective. En procédant par une analyse contextuelle de faits historiques et une lecture typomorphologique de la percée de la Casbah, cette recherche attire l’attention sur l’ampleur de certaines décisions gouvernementales concernant l’aménagement de l’espace urbain et la conservation de l’héritage architectural à court, moyen et long termes. Elle renseigne aussi sur le rôle des collectivités, de l’élite et des professionnels dans la canalisation de ces décisions pour ou contre leur droit à la ville.

La légalité de l'intervention militaire française au Mali : contribution à l’étude du cadre juridique de la lutte armée contre le terrorisme international

Mémoire récipiendaire de la mention "Excellent", avec les félicitations du jury.

Reflections on quasi-loss of nationality in comparative, international and European perspective. CEPS Liberty and Security in Europe No. 66/August 2014

This paper focuses on situations in which a person is said never to have had the nationality of a country, even though (s)he assumed (and in many cases the authorities of the country concerned shared that assumption) that (s)he possessed that nationality. Contrary to situations of loss of nationality, where something is taken away that had existed, quasi-loss involves situations in which nationality was never acquired. This contribution seeks to examine whether a person should under certain circumstances be protected against quasi-loss of nationality. In order to do so, the paper first maps out situations of quasi-loss in EU member states, describing typical cases in which a person never acquired the nationality of the country, although (s)he was at some time considered as a national. Drawing on this taxonomy, the paper attempts to uncover whether national, European and international laws offer some protection, and if yes, to which extent, for situations of quasi-loss. It concludes with outlining best practices which Member States should comply with in handling such situations.

Between Irrelevance and Integration? New Challenges to Diplomacy in the 21st Century and the Role of the EEAS. EU Diplomacy Paper No. 8, November 2014

The changing nature of diplomacy poses new challenges for diplomatic actors in the 21st century, who have to adapt their structures in order to remain relevant on the international stage. The growing interdependence and complexity of issues necessitate a more networked approach to diplomacy, while states retain their predominance in diplomacy. The main underlying challenge of modern diplomacy therefore requires finding a balance between traditional and new elements. This paper examines to what extent the European External Action Service (EEAS) meets the new challenges of modern diplomacy and copes with the diverse interests of the other stakeholders involved, namely the institutions and Member States of the European Union (EU). On the basis of a conceptual framework of modern diplomacy and an analysis of the different aspects of the EEAS’ structures, the paper argues that the EEAS does not fully meet the new challenges to diplomacy, since the interests of the other stakeholders put constraints on its free development. The latter therefore have to choose between irrelevance and integration with regard to EU foreign policy and the future of the EEAS.

New Approaches, Alternative Avenues and Means of Access to Asylum Procedures for Persons Seeking International Protection. CEPS Liberty and Security in Europe No. 77/ January 2015

This study examines the workings of the Common European Asylum System (CEAS), in order to assess the need and potential for new approaches to ensure access to protection for people seeking it in the EU, including joint processing and distribution of asylum seekers. Rather than advocating the addition of further complexity and coercion to the CEAS, the study proposes a focus on front-line reception and streamlined refugee status determination, in order to mitigate the asylum challenges facing Member States, and vindicate the rights of asylum seekers and refugees according to the EU acquis and international legal standards. Joint processing could contribute to front-line reception and processing capacity, but is no substitute for proper investment in national systems. The Dublin system as currently configured leads inexorably to increasing coercion and detention, and must thus be reconfigured to remove coercion as a principle and ensure consistency with human rights and other fundamental values of the EU.

The Legal Status and Influence of Decisions of International Organizations and other Bodies in the European Union. College of Europe Research Paper in Law 01/2014

Introduction. The European Union’s external action is not only defined by its influence on international developments, but also by its ability and the need to respond to those developments. While traditionally many have stressed the EU’s ‘autonomy’, over the years its ‘dependence’ on global developments has become more clear.2 International law has continued to play a key role in, not only in the EU’s external relations, but also in the Union’s own legal order.3 The purpose of this paper is not to assess the role or performance of the EU in international institutions.4 Rather it purports to reverse the picture and focus on a somewhat under-researched topic: the legal status of decisions of international organizations in the EU’s legal order.5 While parts of the status of these decisions relate to the status of international agreements and international customary law, it can be argued that decisions of international organizations and other international bodies form a distinct category. In fact, it has been observed that “this phenomenon has added a new layer of complexity to the already complex law of external relations of the European Union”.6 Emerging questions relate to the possible difference between decisions of international organizations of which the EU is a member (such as the FAO) and decisions of organizations where it is not (irrespective of existing competences in that area – such as in the ILO). Questions also relate to the hierarchical status of these decisions in the EU’s legal order and to the possibility of them being invoked in direct or indirect actions before the Court of Justice. This contribution takes a broad perspective on decisions of international organizations by including decisions taken in other international institutions which do not necessarily comply with the standard definition of international organizations,7 be it bodies set-up by multilateral conventions or informal (transnational / regulatory) bodies. Some of these bodies are relatively close to the EU (such as the Councils established by Association Agreements – see further Section 5 below); others operate at a certain distance. Limiting the analysis to formal international organizations will not do justice to the manifold relationships between the European Union and various international bodies and to the effects of the norms produced by these bodies. The term ‘international decisions’ is therefore used to refer to any normative output of international institutional arrangements.

The “New World Order”: From Unilateralism to Cosmopolitanism. CES Germany & Europe Working Papers, no. 04.1, 26 January, 2004

On January 26, 2004, the topic of the CES-Berlin Dialogues was "The 'New World Order': From Unilateralism to Cosmopolitanism." It was the second in a series of four meetings organized in Berlin under the med_title 'Redefining Justice.' The session was intended to examine successful and failed arenas of cooperation between the US and Europe; political misunderstandings and conscious manipulation; and models for future transatlantic relations. The presenters were Jeffrey Herf, Professor of History, University of Maryland, and Prof. Dr. Jürgen Neyer, Professor of International Political Economy, Ludwig-Maximilians-University of Munich, and Heisenberg Fellow of the Deutsche Forschungsgemeinschaft at the Department of Political and Social Sciences of the Freie Universität Berlin. Jeffrey Herf was asked to speak on the basic tenets of U.S. foreign policy in the administration of President George W. Bush, and Jürgen Neyer focused on the European view of international relations and conduct in the period since the invasion of Iraq.

Restoring Order in Global Health Governance: Do Metagovernance Norms Affect Interorganizational Convergence? CES Open Forum Series #23, 2014-2015

This paper theorizes about the convergence of international organizations in global health governance, a field of international cooperation that is commonly portrayed as particularly hit by institutional fragmentation. Unlike existing theories on interorganizationalism that have mainly looked to intra- and extraorganizational factors in order to explain why international organizations cooperate with each other in the first place, the paper is interested in the link between causes and systemic effects of interorganizational convergence. The paper begins by defining interorganizational convergence. It then proceeds to discuss why conventional theories on interorganizational- ism fail to explain the aggregate effects of convergence between IOs in global (health) governance which tend to worsen rather than cushion fragmentation — so-called "hypercollective action" (Severino & Ray 2010). In order to remedy this explanatory blind-spot the paper formulates an alternative sociological institutionalist theory on interorganizational convergence that makes two core theoretical propositions: first that emerging norms of metagovernance are a powerful driver behind interorganizational convergence in global health governance, and secondly that IOs are engaged in a fierce meaning-struggle over these norms which results in hypercollective action. In its empirical part, the paper’s core theoretical propositions are corroborated by analyzing discourses and practices of interorganizational convergence in global health. The empirical analysis allows drawing two far-reaching conclusions. On the one hand, interorganizational harmonization has emerged as a largely undisputed norm in global health which has been translated into ever more institutionalized forms of interorganizational cooperation. On the other, discourses and practices of interorganizational harmonization exhibit conflicts over the ordering principles according to which the policies and actions of international organizations with overlapping mandates and missions should be harmonized. In combination, these two empirical findings explain why interorganizational convergence has so far failed to strengthen the global health architecture.

Report of the ESIL IEL IG Göttingen Conference on PTAs and World Economic Order

Presentation of the main findings of the first ESIL IEL IG Conference in Göttingen in March 2014. The conference provided a thorough overview over all of the current legal issues relating to preferentialism. Particularly the discussions on the role of academia in solving these new challenges in global trade regulation were perceived as fruitful and inspiring.

La modernisation de Tunis : un urbanisme et une architecture d’État au miroir d’une anthologie de la percée dans la médina (1881-1987)

Cette thèse traite de quelques moments clés dans l’histoire urbaine et architecturale moderne de la ville de Tunis. Elle les aborde conjointement à la problématique du percement de son noyau historique : la médina, née d’un projet de modernisation urbaine lancé par les beys de Tunis à la fin du XIXe siècle, poursuivi par le protectorat français de 1881 à 1956, puis par le gouvernement indépendant de 1956 à 1987. Partant, la recherche est répartie sur trois temps avec, au centre, le projet de la percée dite de la Casbah adopté par le Président Bourguiba à la fin de 1959. Pour plusieurs raisons, ce moment est cité rapidement dans la littérature malgré son importance dans la compréhension du visage actuel de la capitale tunisienne. Pour le saisir, on a dû retourner aux premières tentatives de percement de la médina de Tunis par le colonisateur français en 1887. Puis, on s’est progressivement approché de l’ancêtre direct de la percée bourguibienne paru sur le Plan directeur de Tunis en 1948. De ce premier temps, on a mis en valeur les stratégies coloniales dans leur gestion du territoire et leur rapport au processus de valorisation/dévalorisation du patrimoine issu de la civilisation arabo-islamique. Le second temps, qui correspond au plan de décolonisation mené par l’État indépendant dès 1955, est marqué par le lancement d’un « concours international ouvert pour une étude d’aménagement de la ville de Tunis » organisé par le Secrétariat d’État aux travaux publics en collaboration avec l’Union internationale des architectes. L’étude de cet événement et du colloque qui l’a suivi a ôté le voile sur ses raisons d’être politico-économiques que dissimulaient les usuels soucis de l’hygiène, de la circulation et de l’embellissement du Grand Tunis. Pour appuyer davantage ces constats, un troisième et dernier temps a été dédié au chantier de Tunis au lendemain du concours. L’accent mis sur les lieux symboliques du pouvoir et le désir obsessif des autorités à se les approprier ont réduit ce chantier à une redistribution concertée des symboles de la souveraineté nationale dans le but de centraliser et de personnifier le pouvoir en place. Le présent travail se situe dans le cadre des études postcoloniales et projette un regard critique sur la décolonisation en rapport avec ce qu’on a taxé d’urbanisme d’État. Propulsé par une certaine perception de la modernité, cet urbanisme est indissociable d’une instrumentalisation politique qui met l’accent sur les questions identitaires et patrimoniales, insiste sur la rupture avec le passé et tend à écarter l’opinion publique des questions inhérentes à l’aménagement du territoire et à la sauvegarde de la mémoire collective. En procédant par une analyse contextuelle de faits historiques et une lecture typomorphologique de la percée de la Casbah, cette recherche attire l’attention sur l’ampleur de certaines décisions gouvernementales concernant l’aménagement de l’espace urbain et la conservation de l’héritage architectural à court, moyen et long termes. Elle renseigne aussi sur le rôle des collectivités, de l’élite et des professionnels dans la canalisation de ces décisions pour ou contre leur droit à la ville.

La légalité de l'intervention militaire française au Mali : contribution à l’étude du cadre juridique de la lutte armée contre le terrorisme international.

Mémoire récipiendaire de la mention "Excellent", avec les félicitations du jury.

Mineralogical composition of the upper 300m of Hole 302-M0002A

During the Arctic Coring Expedition (ACEX), a 428-m-thick sequence of Upper Cretaceous to Quaternary sediments was penetrated. The mineralogical composition of the upper 300 m of this sequence is presented here for the first time. Heavy and clay mineral associations indicate a major and consistent shift in provenance, from the Barents-Kara - western Laptev Sea region, characterized by presence of common clinopyroxene, to the eastern Laptev-East Siberian seas in the upper part of the section, characterized by common hornblende (amphibole). Sea ice originating from the latter source region must have survived at least one summer melt cycle in order to reach the ACEX drill site, if considering modern sea ice trajectories and velocities. This shift in mineral assemblages probably represents the onset of a perennial sea ice cover in the Arctic Ocean, which occurred at about 13 Ma, thus suggesting a coeval freeze in the Arctic and Antarctic regions.