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Full-Text Articles in Physical Sciences and Mathematics
Polymer Depletion Effects Near Mesoscopic Particles, Andreas Hanke, E. Eisenriegler, S. Dietrich
Polymer Depletion Effects Near Mesoscopic Particles, Andreas Hanke, E. Eisenriegler, S. Dietrich
Physics and Astronomy Faculty Publications and Presentations
The behavior of mesoscopic particles dissolved in a dilute solution of long, flexible, and nonadsorbing polymer chains is studied by field-theoretic methods. For spherical and cylindrical particles the solvation free energy for immersing a single particle in the solution is calculated explicitly. Important features are qualitatively different for self-avoiding polymer chains as compared with ideal chains. The results corroborate the validity of the Helfrich-type curvature expansion for general particle shapes and allow for quantitative experimental tests. For the effective interactions between a small sphere and a wall, between a thin rod and a wall, and between two small spheres, quantitative …
Detecting An Association Between Gamma Ray And Gravitational Wave Bursts, Lee Samuel Finn, Soumya Mohanty, Joseph D. Romano
Detecting An Association Between Gamma Ray And Gravitational Wave Bursts, Lee Samuel Finn, Soumya Mohanty, Joseph D. Romano
Physics and Astronomy Faculty Publications and Presentations
If γ-ray bursts (GRBs) are accompanied by gravitational wave bursts (GWBs) the correlated output of two gravitational wave detectors evaluated in the moments just prior to a GRB will differ from that evaluated at other times. We can test for this difference without prior knowledge of either the GWB wave form or the detector noise spectrum. With a model for the GRB source population and GWB spectrum we can put a limit on the in-band rms GWB signal amplitude. Laser-Interferometer Gravitational Wave Observatory I detector observations coincident with 1000 GRB observations could lead us to exclude with 95% confidence associated …
Apex: Cross-Platform Analysis Program For Exafs, N. Dimakis, Grant Bunker
Apex: Cross-Platform Analysis Program For Exafs, N. Dimakis, Grant Bunker
Physics and Astronomy Faculty Publications and Presentations
We have developed version 1.0 of a freely available (including source code) suite of basic X-Ray Absorption Fine Structure (XAFS) data analysis programs for data reduction and single scattering analysis. This package is based on the University of Washington (UW/NRL) Fortran 77 programs that are available on the International XAFS Society (IXS) database, complemented by a graphical TCL/TK scripting language based user interface which runs virtually unchanged between platforms, using the native look and feel of the corresponding platform. The package has been tested on MacOS 8.1, Linux, IRIX, Windows95 and NT. Particular emphasis is placed on simplicity, reliability, and …
Observational Limit On Gravitational Waves From Binary Neutron Stars In The Galaxy, B. Allen, J. K. Blackburn, J. D. Creighton, Teviet Creighton
Observational Limit On Gravitational Waves From Binary Neutron Stars In The Galaxy, B. Allen, J. K. Blackburn, J. D. Creighton, Teviet Creighton
Physics and Astronomy Faculty Publications and Presentations
Using optimal matched filtering, we search 25 hours of data from the LIGO 40-m prototype laser interferometric gravitational-wave detector for gravitational-wave chirps emitted by coalescing binary systems within our Galaxy. This is the first test of this filtering technique on real interferometric data. An upper limit on the rate R of neutron star binary inspirals in our Galaxy is obtained: with 90% confidence, R<0.5h−1. Similar experiments with LIGO interferometers will provide constraints on the population of tight binary neutron star systems in the Universe.
Critical Adsorption On Curved Objects, Andreas Hanke, S. Dietrich
Critical Adsorption On Curved Objects, Andreas Hanke, S. Dietrich
Physics and Astronomy Faculty Publications and Presentations
A systematic field-theoretical description of critical adsorption on curved objects such as spherical or rodlike colloidal particles immersed in a fluid near criticality is presented. The temperature dependence of the corresponding order parameter profiles and of the excess adsorption are calculated explicitly. Critical adsorption on elongated rods is substantially more pronounced than on spherical particles. It turns out that, within the context of critical phenomena in confined geometries, critical adsorption on a microscopically thin ‘‘needle’’ represents a distinct universality class of its own. Under favorable conditions the results are relevant for the flocculation of colloidal particles.
Critical Adsorption Near Edges, Andreas Hanke, M. Krech, F. Schlesener, S. Dietrich
Critical Adsorption Near Edges, Andreas Hanke, M. Krech, F. Schlesener, S. Dietrich
Physics and Astronomy Faculty Publications and Presentations
Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys, or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function, and determine the critical exponents η∥ and η⊥ for the so-called normal transition.
Rapid Single- And Multiple-Scattering Exafs Debye-Waller Factor Calculations On Active Sites Of Metalloproteins, N. Dimakis, M-Ali Al-Akhras, Grant Bunker
Rapid Single- And Multiple-Scattering Exafs Debye-Waller Factor Calculations On Active Sites Of Metalloproteins, N. Dimakis, M-Ali Al-Akhras, Grant Bunker
Physics and Astronomy Faculty Publications and Presentations
This paper describes recent results using our approach to calculating self-consistently single (SS) and multiple-scattering (MS) Debye- Waller factors (DWF) on active sites of metalloproteins. The calculation of MS DWF, together with the Feff7 program allows us to simulate ab-initio EXAFS spectra for a given temperature systems with no adjustable parameters. In our latest report (Dimakis N., and Bunker G., 1998) we calculate, using density functional and semiempirical approaches, the SS and MS DWF for small molecules and compared them to Raman, infrared and EXAFS spectra. In this report calculation of DWFs is done for tetrahedral Zn imidazole, a complex …