On the limits of Köhler activation theory: How do collision and coalescence affect the activation of aerosols?

Activation is necessary to form a cloud droplet from an aerosol, and it is widely accepted that it occurs as soon as a wetted aerosol grows beyond its critical radius. Traditional Köhler theory assumes that this growth is driven by the diffusion of water vapor. However, if the wetted aerosols are large enough, the coalescence of two or more particles is an additional process for accumulating sufficient water for activation. This transition from diffusional to collectional growth marks the limit of traditional Köhler theory and it is studied using a Lagrangian cloud model in which aerosols and cloud droplets are represented by individually simulated particles within large-eddy simulations of shallow cumuli. It is shown that the activation of aerosols larger than 0. 1μm in dry radius can be affected by collision and coalescence, and its contribution increases with a power-law relation toward larger radii and becomes the only process for the activation of aerosols larger than 0. 4-0. 8μm depending on aerosol concentration. Due to the natural scarcity of the affected aerosols, the amount of aerosols that are activated by collection is small, with a maximum of 1 in 10000 activations. The fraction increases as the aerosol concentration increases, but decreases again as the number of aerosols becomes too high and the particles too small to cause collections. Moreover, activation by collection is found to affect primarily aerosols that have been entrained above the cloud base.DFG/RA 617/27-

Validations, further developments, and applications of a Lagrangian cloud model

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PriCL: Creating a Precedent A Framework for Reasoning about Privacy Case Law

We introduce PriCL: the first framework for expressing and automatically reasoning about privacy case law by means of precedent. PriCL is parametric in an underlying logic for expressing world properties, and provides support for court decisions, their justification, the circumstances in which the justification applies as well as court hierarchies. Moreover, the framework offers a tight connection between privacy case law and the notion of norms that underlies existing rule-based privacy research. In terms of automation, we identify the major reasoning tasks for privacy cases such as deducing legal permissions or extracting norms. For solving these tasks, we provide generic algorithms that have particularly efficient realizations within an expressive underlying logic. Finally, we derive a definition of deducibility based on legal concepts and subsequently propose an equivalent characterization in terms of logic satisfiability.Comment: Extended versio

The when, what, where and why of European Union sanctions

The decisions to impose sanctions on Russia and to lift them on Iran, in opposition to the wishes of the United States, contributed to the elevation of the profile of the European Union among the main global actors in international politics. However, the EU imposes sanctions since the spring of 1994, shortly after the entry into force of the Treaty of Maastricht. Even though the EU consequently has 26 years of experience herewith, EU sanctions have been mostly studied only on a case-by-case basis. The aim of this article is to provide an up-to-date and comprehensive overview of the experience of the EU with sanctions. Specifically, it presents the results of a newly constructed database of EU autonomous sanctions constituted by 48 cases of these restrictive measures, which have been subdivided in 85 episodes. The analysis revolves around four questions that we asked in each case: when sanctions were in force, what type(s) were used, where the targets were located and why restrictive measures were imposed. The analysis of the empirical database leads to observations about the EU as an international actor and, more generally, on the trends vis-a-vis the utilisation of sanctions as a foreign policy instrument

Dithiocarbamate/Trithiocarbonate: Von ionischen Flüssigkeiten über Metall-Komplexe zu Halbleitermaterialien

Das Ziel dieser Arbeit war die Untersuchung eines lösungsbasierten Herstellungsprozesses von Metallsulfid-Halbleitermaterialien wie MoS2 durch thermische Zersetzung geeigneter Präkursoren. Dithiocarbamate und Trithiocarbonate zeigen sowohl als anionischer Baustein in ionischen Flüssigkeiten (IL), als auch als Liganden in Metall-Komplexen großes Potential bei der Extraktion von Metallen sowie der Synthese von Halbleitermaterialien. Eine neue Darstellungsweise für ionische Flüssigkeiten mit Dithiocarbamat- bzw. Trithiocarbonat wurde entwickelt, die hohe Ausbeuten und Reinheit liefert. Des weiteren wurden Indium- und Galliumkomplexe mit Dithiocarbamat-Liganden primärer und sekundärer Amine dargestellt und hinsichtlich ihrer thermischen Zersetzung untersucht. Weiterhin wurden MoS2-Präkursoren auf Basis von Tetrathiomolybdaten sowie schwefelreichen Molybdänkomplexen identifiziert, synthetisiert und charakterisiert. Geeignete MoS2-Präkursoren wurden in Beschichtungsexperimenten mittels Spincoating auf Si-Wafer aufgetragen, thermisch zersetzt und auf die Bildung von MoS2 untersucht

The “SimCo” Simulator as a TA Tool: Experiments on Traffic Management

Das Simulationsframework „SimCo“ erlaubt es, die Steuerung komplexer, netzwerkförmiger, soziotechnischer (Infrastruktur-)Systeme zu untersuchen – beispielsweise die des Verkehrs- oder Energiesystems. SimCo basiert auf den Prinzipien der agentenbasierten Modellierung und Simulation. Dynamiken auf der Systemebene werden durch die Interaktion einer Vielzahl strategisch handelnder, heterogener Agenten erzeugt. Mit Hilfe von Simulationsexperimenten lassen sich unterschiedliche Szenarien (mit politisch definierten Zielvorstellungen) hinsichtlich ihrer Wirksamkeit sowie möglicher nicht-intendierter Nebenfolgen testen, denn der Steuerungserfolg hängt letztlich von den Reaktionen der Agenten auf der Mikro-Ebene ab. Ein abstraktes, urbanes Verkehrssystem dient als Anwendungsfall und lässt eine Mischung aus weichen und harten Steuerungsmaßnahmen vielversprechend erscheinen.The simulation framework “SimCo” aims at investigating the governance of complex, network-like, socio-technical (infrastructure) systems like transportation or energy supply. SimCo applies the method of agent-based modeling and simulation, meaning that dynamics at the system level result from the interactions of strategically acting, heterogeneous agents. Since successful governance depends on the agents’ reaction at the micro level, simulation experiments with what-if scenarios (with politically defined objectives) can be used to test different governance measures regarding their efficiency and possible unintended side effects. An abstract, urban road transportation system serves as an exemplary case, its results indicate a promising combination of soft and strong control measures