29,749 research outputs found
Analysis of a test method for measuring resonant frequencies of loaded hydraulic feed lines
Analysis of test facility for measuring resonant frequencies of fluid feed line
Discrete orbits, recurrence and solvable subgroups of Diff(C^2,0)
We discuss the local dynamics of a subgroup of Diff(C^2,0) possessing locally
discrete orbits as well as the structure of the recurrent set for more general
groups. It is proved, in particular, that a subgroup of Diff(C^2,0) possessing
locally discrete orbits must be virtually solvable. These results are of
considerable interest in problems concerning integrable systems.Comment: The first version of this paper and "A note on integrability and
finite orbits for subgroups of Diff(C^n,0)" are an expanded version of our
paper "Discrete orbits and special subgroups of Diff(C^n,0)". An intermediate
version re-submitted to the journal on March 2015 is available at
http://www.fep.up.pt/docentes/hreis/publications.htm where there is also a
comparison between these 3 version
LibCPIXE: a PIXE simulation open-source library for multilayered samples
Most particle induced X-ray emission (PIXE) data analysis codes are not
focused on handling multilayered samples. We have developed an open-source
library called "LibCPIXE", for PIXE data analysis. It is written in standard C
and implements functions for simulating X-ray yields of PIXE spectra taken from
arbitrary samples, including multilayered targets. The library is designed to
be fast, portable, modular and scalable, as well as to facilitate its
incorporation into any existing program. In order to demonstrate the
capabilities of the library, a program called CPIXE was developed and used to
analyze various real samples involving both bulk and layered samples. Just as
the library, the CPIXE source code is freely available under the General Public
License. We demonstrate that it runs both under GNU/Linux systems as well as
under MS Windows. There is in principle no limitation to port it to other
platforms
Simultaneous PIXE and RBS data analysis using Bayesian Inference with the DataFurnace code
The Rutherford Backscattering Spectroscopy (RBS) and Particle Induced X-ray
Emission (PIXE) techniques can be used to obtain complementary information
about the characteristics of a sample but, traditionally, a gap has separated
the available computer codes for analyzing data from each technique, being hard
to simultaneously analyze data from the same sample. The recent development of
a free and open source library, LibCPIXE, for PIXE simulation and analysis of
arbitrary multilayered samples, has permitted to integrate this technique into
the DataFurnace code which already handles many other IBA techniques such as
Rutherford and non-Rutherford backscattering, elastic recoil detection, and
non-resonant nuclear reaction analysis. The fitting capabilities of DataFurnace
can therefore now be applied to PIXE spectra as well, including the Bayesian
Inference analysis and the simultaneous and coherent fitting of multiple
spectra from different techniques. Various examples are presented in which the
simultaneous RBS and PIXE analysis allows us to obtain consistent results that
cannot be obtained by independent analysis of the data from each technique.Comment: 10 pages, 5 figures. Paper initially presented to IBA2005. Please
cite the published version (DOI:10.1016/j.nimb.2006.03.190
Quantum evolution of scalar fields in Robertson-Walker space-time
We study the field theory in a flat Robertson-Walker
space-time using the functional Sch\"odinger picture. We introduce a simple
Gaussian approximation to analyze the time evolution of pure states and we
establish the renormalizability of the approximation. We also show that the
energy-momentum tensor in this approximation is finite once we consider the
usual mass and coupling constant renormalizations.Comment: Revtex file, 19 pages, no figures. Compressed ps version available at
http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-912.ps.Z or at
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-912.ps.
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