Tunable structures of mixtures of magnetic particles in liquid-crystalline matrices

We investigate the self-organization of a binary mixture of similar sized rods and dipolar soft spheres by means of Monte-Carlo simulations. We model the interparticle interactions by employing anisotropic Gay-Berne, dipolar and soft-sphere interactions. In the limit of vanishing magnetic moments we obtain a variety of fully miscible liquid crystalline phases including nematic, smectic and lamellar phases. For the magnetic mixture, we find that the liquid crystalline matrix supports the formation of orientationally ordered ferromagnetic chains. Depending on the relative size of the species the chains align parallel or perpendicular to the director of the rods forming uniaxial or biaxial nematic, smectic and lamellar phases. As an exemplary external perturbation we apply a homogeneous magnetic field causing uniaxial or biaxial ordering to an otherwise isotropic state.Comment: 11 pages, 12 figure

Low-energy photoelectron transmission through aerosol overlayers

The transmission of low-energy (<1.8eV) photoelectrons through the shell of core-shell aerosol particles is studied for liquid squalane, squalene, and DEHS shells. The photoelectrons are exclusively formed in the core of the particles by two-photon ionization. The total photoelectron yield recorded as a function of shell thickness (1-80nm) shows a bi-exponential attenuation. For all substances, the damping parameter for shell thicknesses below 15nm lies between 8 and 9nm, and is tentatively assigned to the electron attenuation length at electron kinetic energies of ~0.5-1eV. The significantly larger damping parameters for thick shells (> 20nm) are presumably a consequence of distorted core-shell structures. A first comparison of aerosol and traditional thin film overlayer methods is provided

Arbitration and third parties.

PhDModern international transactions have become extremely complicated, requiring the participation of several parties for the delivery of large-scale projects. However. multiparty commercial projects are invariably executed through several bilateral contracts providing for bilateral dispute resolution arrangements. Some of the contracts might include a jurisdiction clause, certain others might provide for arbitration, while others may not contain any dispute resolution provisions at all. This practice leads to "jurisdictional fragmentation of the multiparty commercial project" where the several parties of a single business plan will fall under the jurisdiction of different adjudicatory fora. Thus. a dispute arising between two persons bound by an arbitration agreement in connection with the multiparty project will have to be resolved exclusively by arbitration between these two parties. Other persons cannot take part in the resolution of the dispute, even if they play an active role in the actual business project. and thus have an interest in the outcome of the dispute. These persons will remain third parties, both to the arbitration agreement and the arbitral award. This study focuses on the role and the interests of the wide group of third parties exhibiting an interest in the dispute pending before a tribunal between two genuine parties. The thesis, in particular, examines whether arbitration agreements can affect persons which are not contractually bound by these agreements. In addition, the thesis explores whether arbitral awards can affect persons that have not participated in the arbitration proceedings The thesis challenges the prevailing contractual approach to the issue of arbitration, focusing exclusively on the contractual characteristics of arbitration ag eements. According to this view, the main question is whether a non-signatory can be contractually bound by an arbitration agreement. The study demonstrates that focusing exclusively on the contractual nature of arbitration agreements obscures the real issue here, which is whether arbitration agreements may have any jurisdictional implications vis-a-vis `third parties'. Accordingly, the thesis takes a jurisdictional approach, and argues that the discussion should be focused on the dispute and on any implications this may have to third parties, rather than on the requirement of consent to arbitration agreements. Regarding the effect of arbitral awards on third parties, the thesis argues for a third-party effect of arbitral awards specially designed for the needs of international arbitration. More specifically, the case is made for the application of an arbitral effect different from that of res judicata, both in terms of quality and intensity, but that is nevertheless conclusive. It is also suggested that the third party effect of an arbitral award should be analogous to the degree of substantive association between the genuine and the false third parties. This is consistent with the basic premise of the whole thesis: the relations between several parties, in terms of jurisdiction and more generally in arbitration procedure, should correspond to the extent of association between those parties, in terms of substantive rights, interests and liability

A novel 1.5 '' quadruple antenna for tri-band GPS applications

A new global positioning system (GPS) antenna is proposed to cover the three GPS bands (L1, L2, and L5, namely 1575, 1227, and 1176 MHz) with the L5 band to be added after 2006. The developed antenna size is only 1.5" x 1.5" in aperture corresponding to lambda/7 x lambda/7 (lambda = free space wavelength) and lambda/13 thick. Quadrature feeding is employed to ensure right-hand circular polarized (RHCP) radiation. The final miniature antenna exhibits a gain greater than 2 dBi, and to our knowledge this is the smallest such size for circular polarized (CP) operation covering all three bands. Detailed parametric simulations leading to the best design along with measurements for the constructed antenna are presented

Analytic vortex solutions in an unusual Mexican hat potential

We introduce an unusual Mexican hat potential, a piecewise parabolic one, and we show that its vortex solutions can be found analytically, in contrast to the case of the standard Psi^4 field theory.Comment: 4 pages and 1 figure (missing in this version

Multiple Transition States and Roaming in Ion-Molecule Reactions: a Phase Space Perspective

We provide a dynamical interpretation of the recently identified `roaming' mechanism for molecular dissociation reactions in terms of geometrical structures in phase space. These are NHIMs (Normally Hyperbolic Invariant Manifolds) and their stable/unstable manifolds that define transition states for ion-molecule association or dissociation reactions. The associated dividing surfaces rigorously define a roaming region of phase space, in which both reactive and nonreactive trajectories can be trapped for arbitrarily long times.Comment: 20 pages, 6 figure

Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

Sunscreen formulations have been developed to provide an artificial protective barrier against the deleterious effects of overexposure to ultraviolet (UV) radiation in humans. Ultrafast pump-probe spectroscopy techniques have been an invaluable tool in recent years for determining the photochemistry of active ingredients in sunscreen formulations, predominantly UV filters, in both the gas- and solution-phases. These measurements have enabled the elucidation of molecular relaxation pathways and photoprotection mechanisms, which are in turn insightful for assessing a filter's photostability and suitability for sunscreen use. In this review, we discuss the benefits of a bottom-up approach: the progression from the study of UV filters for sunscreens in vacuum, away from the influences of any solvent; in solution, to investigate the relaxation pathways of potential sunscreen filters in closer to real-life conditions, whilst exploring the merits of selective functionalisation to improve their characteristics; and beyond, to current advances that are mimicking the application of sunscreen formulations to the surface of the skin