3,703 research outputs found
Linearized cloudpoint curve correlation for ternary systems consisting of one polymer, one solvent and one non-solvent
A linear correlation function is found for cloudpoint composition curves of ternary systems consisting of one polymer, one solvent and one non-solvent. The conditions for validity of this correlation function appear to be that the polymer is strongly incompatible with the non-solvent, and that only liquid-liquid demixing occurs. The linearized cloudpoint (LCP) curve is interpreted in terms of the various parameters occurring in the Flory-Huggins theory. The slope of the LCP line appears to be only dependent on the molar volumes of the components. Information about the binary Flory-Huggins interaction parameters and their concentration dependence can be obtained from the intercept of the linearized curve. Cloudpoints induced by crystallization do not follow the correlation. This gives an opportunity to distinguish between crystallization and liquid-liquid demixing without any additional experiments
Mass transfer and thermodynamics during immersion precipitation for a two-polymer system: Evaluation with the system PES-PVP-NMP-water
An extended version of the mass transfer model by Reuvers et al. for a four-component system is evaluated, which is shown to be generally valid for short times. The thermodynamics under these circumstances are evaluated, together with the kinetics. Initial composition paths (concentration profiles) are calculated. It appears that delay of demixing is not possible when a polymeric additive is used, which is soluble in the nonsolvent, while the velocity of demixing decreases. The calculations are evaluated for the system poly(ether sulfone)-poly(vinylpyrrolidone)-N-methylpyrrolidone-water by means of light transmission measurements during immersion precipitation, for a wide range of compositions of the polymer solution and coagulation bath
EU Region-Building in the Neighbourhood. The Eastern Partnership’s Contribution in the South Caucasus. EU Diplomacy Paper 04/2017
The promotion of regionalisation is part of the foreign policy of the European Union
(EU). However, a closer understanding of the mechanisms by which its policies work
towards this goal is lacking. Taking the South Caucasus as a case, this paper asks how
the Eastern Partnership contributes to region-building. Based on policy analysis,
discourse analysis and interviews, the study adopts a four-layered understanding of
region-building as the promotion of closer cross-border contacts: Regarding
economic linkages, the analysis underlines Georgia’s gateway function. On political
linkages, the analysis assigns importance to regulatory harmonisation as a bottom-up
tool against divisive regional discourses. Cross-border management fulfils a similar
technical role for the promotion of security linkages. Concerning cultural linkages,
Georgia is analysed as a hub for common socialisation and people-to-people
contacts. Derived from these findings, the paper induces three general hypotheses
about the mechanisms of EU contributions to region-building: while combining
bilateral with multilateral approaches and functional spill-over effects contribute to
region-building, the inclusion of non-state actors does not advance region-building
Regulating competition in the digital network industry: A proposal for progressive ecosystem regulation
The digital sector is a cornerstone of the modern economy, and regulating digital enterprises can be considered the new frontier for regulators and competition authorities. To capture and address the competitive dynamics of digital markets we need to rethink our (competition) laws and regulatory strategies. The thesis develops new approaches to regulating digital markets by viewing them as part of a network industry. By combining insights from our experiences with existing regulation in telecommunications with insights from economics literature and management theory, the thesis concludes by proposing a new regulatory framework called ‘progressive ecosystem regulation’. The thesis is divided in three parts and has three key findings or contributions. The first part explains why digital platforms such as Google’s search engine, Meta’s social media platforms and Amazon’s Marketplace are prone to monopolization. Here, the thesis develops a theory of ‘digital natural monopoly’, which explains why competition in digital platform markets is likely to lead to concentration by its very nature.The second part of the thesis puts forward that competition in digital markets persists, even if there is monopoly in a market. Here, the thesis develops a conceptual framework for competition between digital ecosystems, which consists of group of actors and products. Digital enterprises compete to carve out a part of the digital network industry where they can exert control, and their strong position in a platform market can be used offensively or defensively to steer competition between ecosystems. The thesis then sets out four phases of ecosystem competition, which helps to explain when competition in the digital network industry is healthy and when it is likely to become problematic.The third and final part of the thesis brings together these findings and draws lessons from our experiences of regulating the network industry for telecommunications. Based on the insights developed in the thesis it puts forward a proposal for ‘progressive ecosystem regulation’. The purpose of this regulation is to protect and empower entrants from large digital ecosystems so that they can develop new products and innovate disruptively. This regulatory framework would create three regulatory pools: a heavily regulated, lightly regulated and entrant pool. The layered regulatory framework allows regulators to adjust who receives protection under the regulation and who faces the burdens relatively quickly, so that the regulatory framework reflects the fast pace of innovation and changing nature of digital markets. With this proposal, the thesis challenges and enriches our existing notions on regulation and specifically how we should regulate digital markets
Paradigmawechsel als Notationswechsel: Saussure – Chomsky
Ich möchte für das Folgende annehmen, daß ein Paradigmenwechse1 in den Wissenschaften sich als Wechsel der methodisch leitenden grammatischen Sätze rekonstruieren läßt. Oder mindestens möchte ich behaupten; die Betrachtung eines Paradigmenwechsels als Wechsel der grammatischen Sätze sei wenigstens bei einer Wissenschaft zwingend: bei der Linguistik. Daß die Linguistik längst keine vorparadigmatische Wissenschaft mehr ist, läßt sich bereits daran erkennen, daß sie sich stark genug fühlt, nicht abseits zu stehen, sondern ihrerseits mit einer linguistischen Definition von Wissenschaft aufzuwarten.[…] Daß es inzwischen Untersuchungen über die Sprache der Physik gibt, die linguistische Ergebnisse berücksichtigen, hat sicherlich unter anderem damit zu tun, daß die Linguistik seit der Jahrhundertwende, seit Ferdinand de Saussure, selbstbewußt und sehr vernehmlich im Chor der Wissenschaften mitgesungen hat, bisweilen so laut, daß viele Wissenschaften, besonders in der Abteilung Geisteswissenschaft, sich gezwungen sahen, die Melodie der Linguistik zu übernehmen, wenn anders sie nicht gänzlich übertönt werden wollten. In dieser Situation ist es also auch für andere Wissenschaften von einigem Interesse, davon Kenntnis zu nehmen, daß in der kräftigen Stimme der Linguistik ziemlich genau um das Jahr 1957 ein etwas abrupter Melodiewechsel nicht zu überhören war: Noam Chomskys Buch 'Syntactic Structures' kündigte weiteren Kreisen eine wissenschaftliche Revolution, ein neues Paradigma an. Das heißt […], daß die Wissenschaft der Grammatik, die ja insgesamt nur aus grammatischen Sätzen besteht, das System ihrer methodologischen, […] rein-grammatischen Sätze gegenüber ihren empirisch-grammatischen Sätzen über einzelne Sprachen gründlich veränderte. Der Linguist würde sagen: die Vorstellung von den linguistischen Universalien änderte sich radikal gegenüber derjenigen, die in dem paradigmatischen Lehrbuch der strukturalistischen Epoche entwickelt worden war, dem Cours de linguistique generale Saussures von 1916. Diese Revolution vom Jahre 1957 möchte ich nun zum Gegenstand einer näheren Betrachtung machen
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