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- ItemCorrelation of carbon nanotube dispersability in aqueous surfactant solutions and polymers(New York, NY [u.a.] : Pergamon Press, 2009) Krause, Beate; Petzold, Gudrun; Pegel, Sven; Pötschke, PetraIn order to assess the dispersability of carbon nanotube materials, tubes produced under different synthesis conditions were dispersed in aqueous surfactant solutions and the sedimentation behaviour under centrifugation forces was investigated using a LUMiFuge stability analyzer. The electrical percolation threshold of the nanotubes after melt mixing in polyamide 6.6 was determined and the state of dispersion was studied. As a general tendency, the nanotubes having better aqueous dispersion stability showed lower electrical percolation threshold and better nanotube dispersion in the composites. This indicates that the investigation of the stability of aqueous dispersions is also able to give information about the nanotubes inherent dispersability in polymer melts, both strongly influenced by the entanglement and agglomerate structure of the tubes within the as-produced nanotube materials. The shape of the nanotubes in the aqueous dispersions was assessed using a SYSMEX flow particle image analyzer and found to correspond to the shape observed from cryofractured surfaces of the polymer composites. © 2008 Elsevier Ltd. All rights reserved.
- ItemInfluence of small scale melt mixing conditions on electrical resistivity of carbon nanotube-polyamide composites(Barking : Elsevier, 2009) Krause, Beate; Pötschke, Petra; Häußler, LianePolyamide 6 (PA6) and polyamide 6.6 (PA66) were filled with multiwalled carbon nanotubes (MWNT) using small scale melt mixing under variation of processing conditions, including temperature, rotation speed, and mixing time. In PA66 an electrical percolation threshold of 1 wt% MWNT was found which is lower than that of PA6 at 2.5-4 wt%. In both cases mixing conditions influenced strongly the dispersion and distribution of CNT and the electrical volume resistivity, whereas crystallisation behaviour was only slightly changed. With increasing mixing energy input remaining agglomerates were less in number and smaller, leading to better dispersion. On the other hand, in samples containing 5 wt% MWNT in PA6 electrical volume resistivity showed a minimum at a quite low energy input and then increased considerably with further input of mixing energy. This increase may be related to MWNT breaking during mixing and encapsulation of MWNT by the polyamide chains. © 2008 Elsevier Ltd. All rights reserved.
- ItemAlgebraic K-Theory and Motivic Cohomology(Zürich : EMS Publ. House, 2009) Huber-Klawitter, Annette; Jannsen, Uwe; Levine, MarcAlgebraic K-theory and the related motivic cohomology are a systematic way of producing invariants for algebraic or geometric structures. Its definition and methods are taken from algebraic topology, but it has also proved particularly fruitful for problems of algebraic geometry, number theory or quadratic forms. 19 one-hour talks presented a wide range of results on K-theory itself and applications. We had a lively evening session trading questions and discussing open problems.
- ItemMini-Workshop: The Pisot Conjecture - From Substitution Dynamical Systems to Rauzy Fractals and Meyer Sets(Zürich : EMS Publ. House, 2009) Damanik, David; Lenz, DanielThis mini-workshop brought together researchers with diverse backgrounds and a common interest in facets of the Pisot conjecture, which relates certain properties of a substitution to dynamical properties of the associated subshift.
- ItemAlgebraische Zahlentheorie(Zürich : EMS Publ. House, 2009) Kisin, Mark; Venjakob, OtmarThe workshop brought together researchers from Europe, the US and Japan, who reported on various recent developments in algebraic number theory and related fields. Dominant themes were p-adic methods, L-functions and automorphic forms but other topics covered a very wide range of algebraic number theory.
- ItemMini-Workshop: Category Theory and Related Fields: History and Prospects(Zürich : EMS Publ. House, 2009) McLarty, Colin; Wright, Michaelhe workshop concerned various topics in the history of category theory and related fields, paying attention to some extent also to open questions, present and possible future development.
- ItemMini-Workshop: Geometry of Quantum Entanglement(Zürich : EMS Publ. House, 2009) Szarek, Stanislaw; Werner, Elisabeth; Zyczkowski, KarolThe workshop aimed at developing interactions between researchers from quantum information theory and from asymptotic geometric analysis. A central notion discussed was the phenomenon of quantum entanglement, which naturally leads to geometric considerations in high-dimensional vector spaces. In these spaces, phenomena such as concentration of measure become prominent and may invalidate our low-dimensional intuition.
- ItemMini-Workshop: Support Varieties(Zürich : EMS Publ. House, 2009) Krause, HenningThe notion of support is a fundamental concept which provides a geometric approach for studying various algebraic structures. The prototype for this has been Quillen’s description of the algebraic variety corresponding to the cohomology ring of a finite group, based on which Carlson introduced support varieties for modular representations. This has made it possible to apply methods of algebraic geometry to obtain representation theoretic information. Their work has inspired the development of analogous theories in various contexts, notably modules over commutative complete intersection rings, and over cocommutative Hopf algebras. The aim of this workshop has been to bring together experts from these fields and to stimulate interaction and exchange of ideas.
- ItemControl Theory: On the Way to New Application Fields(Zürich : EMS Publ. House, 2009) Helmke, Uwe; Sontag, EduardoControl theory is an interdisciplinary field that is located at the crossroads of pure and applied mathematics with systems engineering and the sciences. Recently, deep interactions are emerging with new application areas, such as systems biology, quantum control and information technology. In order to address the new challenges posed by the new application disciplines, a special focus of this workshop has been on the interaction between control theory and mathematical systems biology. To complement these more biology oriented focus, a series of lectures in this workshop was devoted to the control of networks of systems, fundamentals of nonlinear control systems, model reduction and identification, algorithmic aspects in control, as well as open problems in control.
- ItemComplex Algebraic Geometry(Zürich : EMS Publ. House, 2009) Kawamata, Yujiro; Tian, Gang; Viehweg, EckartThe Conference focused on several classical and novel theories in the realm of complex algebraic geometry, such as Algebraic surfaces, Moduli theory, Minimal Model Program, Abelian Varieties, Holomorphic Symplectic Varieties, Homological algebra, Kähler manifolds theory, Holomorphic dynamics, Quantum cohomology.