2,010 research outputs found
Consistent multiphase-field theory for interface driven multidomain dynamics
We present a new multiphase-field theory for describing pattern formation in
multi-domain and/or multi-component systems. The construction of the free
energy functional and the dynamic equations is based on criteria that ensure
mathematical and physical consistency. We first analyze previous
multiphase-field theories, and identify their advantageous and disadvantageous
features. On the basis of this analysis, we introduce a new way of constructing
the free energy surface, and derive a generalized multiphase description for
arbitrary number of phases (or domains). The presented approach retains the
variational formalism; reduces (or extends) naturally to lower (or higher)
number of fields on the level of both the free energy functional and the
dynamic equations; enables the use of arbitrary pairwise equilibrium
interfacial properties; penalizes multiple junctions increasingly with the
number of phases; ensures non-negative entropy production, and the convergence
of the dynamic solutions to the equilibrium solutions; and avoids the
appearance of spurious phases on binary interfaces. The new approach is tested
for multi-component phase separation and grain coarsening
Hydrodynamic theory of freezing: Nucleation and polycrystalline growth
Structural aspects of crystal nucleation in undercooled liquids are explored
using a nonlinear hydrodynamic theory of crystallization proposed recently [G.
I. Toth et al., J. Phys.: Condens. Matter 26, 055001 (2014)], which is based on
combining fluctuating hydrodynamics with the phase-field crystal theory. We
show that in this hydrodynamic approach not only homogeneous and heterogeneous
nucleation processes are accessible, but also growth front nucleation, which
leads to the formation of new (differently oriented) grains at the solid-liquid
front in highly undercooled systems. Formation of dislocations at the
solid-liquid interface and interference of density waves ahead of the
crystallization front are responsible for the appearance of the new
orientations at the growth front that lead to spherulite-like nanostructures
The Use and Abuse of Authority: an Investigation of the [Exousia] Passages in Revelation
The purpose of this dissertation is to carry outa linguistic, structural, and exegetical investigation of the term ἐξουσία as it occurs in the Greek text of the Apocalypse.
Chapter 1 provides an overview of the pertinent literature dealing with ἐξουσία. The review follows a chronological order to demonstrate a trend in the development of ἐξουσία studies. Earlier works put more emphasis on the meaning of power or authority, whereas recent studies point to liberty and right as the primary meaning of ἐξουσία. The current tendency emphasizes philosophical and socio-ethical aspects without due consideration of the etymology of the term.
Chapter 2 surveys the usage of ἐξουσία in nonbiblical (Greco-Roman, Papyri and Inscriptions, Jewish apocalyptic, Qumran, Hellenistic Jewish, Rabbinic) and biblical (LXX, Biblia Hebraica, Greek NT) literary sources that are linguistic backgrounds to the meaning of the term. The Greco-Roman and Hellenistic Jewish works generally employ ἐξουσία with regard to human power relationships. The NT use of the term closely follows the LXX and the Jewish apocalyptic usage particularly in the area of delegated power/authority in human and supernatural relationships.
Chapter 3 focuses on the specifics of the twenty-one ἐξουσία occurrences in Revelation. These passages are investigated in the literary context and structure of the book. The role ἐξουσία plays in the overall literary context of the Apocalypse is further demonstrated by microstructural analyses of the passages. The term plays a special focusing role both in the macro- and the microstructures of the Apocalypse. Thus, it significantly contributes to the central message of Revelation, which is the activity and judgment of antidivine powers.
In the summary and conclusions of the dissertation the findings of the research are given. Theological and ethical implications are pointed out, and some areas for further study are suggested
NLIE for hole excited states in the sine-Gordon model with two boundaries
We derive a nonlinear integral equation (NLIE) for some bulk excited states
of the sine-Gordon model on a finite interval with general integrable boundary
interactions, including boundary terms proportional to the first time
derivative of the field. We use this NLIE to compute numerically the dimensions
of these states as a function of scale, and check the UV and IR limits
analytically. We also find further support for the ground-state NLIE by
comparison with boundary conformal perturbation theory (BCPT), boundary
truncated conformal space approach (BTCSA) and the boundary analogue of the
Luscher formula.Comment: 31 pages, LaTeX; graphicx, epstopdf, 4 figure
The spectrum of tachyons in AdS/CFT
We analyze the spectrum of open strings stretched between a D-brane and an
anti-D-brane in planar AdS/CFT using various tools. We focus on open strings
ending on two giant gravitons with different orientation in
and study the spectrum of string excitations using the following approaches:
open spin-chain, boundary asymptotic Bethe ansatz and boundary thermodynamic
Bethe ansatz (BTBA). We find agreement between a perturbative high order
diagrammatic calculation in SYM and the leading finite-size
boundary Luscher correction. We study the ground state energy of the system at
finite coupling by deriving and numerically solving a set of BTBA equations.
While the numerics give reasonable results at small coupling, they break down
at finite coupling when the total energy of the string gets close to zero,
possibly indicating that the state turns tachyonic. The location of the
breakdown is also predicted analytically.Comment: 40 pages, lots of figures, v2: typos corrected, accepted for
publication in JHE
Observational calibration of the projection factor of Cepheids. II. Application to nine Cepheids with HST/FGS parallax measurements
The distance to pulsating stars is classically estimated using the
parallax-of-pulsation (PoP) method, which combines spectroscopic radial
velocity measurements and angular diameter estimates to derive the distance of
the star. An important application of this method is the determination of
Cepheid distances, in view of the calibration of their distance scale. However,
the conversion of radial to pulsational velocities in the PoP method relies on
a poorly calibrated parameter, the projection factor (p-factor). We aim to
measure empirically the value of the p-factors of a homogeneous sample of nine
Galactic Cepheids for which trigonometric parallaxes were measured with the
Hubble Space Telescope Fine Guidance Sensor. We use the SPIPS algorithm, a
robust implementation of the PoP method that combines photometry,
interferometry, and radial velocity measurements in a global modeling of the
pulsation. We obtained new interferometric angular diameters using the PIONIER
instrument at the Very Large Telescope Interferometer, completed by data from
the literature. Using the known distance as an input, we derive the value of
the p-factor and study its dependence with the pulsation period. We find the
following p-factors: 1.20 0.12 for RT Aur, 1.48 0.18 for T Vul,
1.14 0.10 for FF Aql, 1.31 0.19 for Y Sgr, 1.39 0.09 for X
Sgr, 1.35 0.13 for W Sgr, 1.36 0.08 for Dor, 1.41
0.10 for Gem, and 1.23 0.12 for Car. These values are
consistently close to p = 1.324 0.024. We observe some dispersion around
this average value, but the observed distribution is statistically consistent
with a constant value of the p-factor as a function of the pulsation period.
The error budget of our determination of the p-factor values is presently
dominated by the uncertainty on the parallax, a limitation that will soon be
waived by Gaia.Comment: 18 pages, 13 figure
In-Process Ultrasonic Evaluation of Spot Weld Quality
While spot welding has wide use in the automotive and aerospace industries there is no acceptable nondestructive testing technique for evaluation of its quality. One of the major metallurgical defects of spot welds, the stick weld, cannot be evaluated at all. There is growing interest in the industry to develop simple production-oriented nondestructive techniques for evaluation of spot weld quality
Improved Cloud and Snow Screening in MAIAC Aerosol Retrievals Using Spectral and Spatial Analysis
An improved cloud/snow screening technique in the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm is described. It is implemented as part of MAIAC aerosol retrievals based on analysis of spectral residuals and spatial variability. Comparisons with AERONET aerosol observations and a large-scale MODIS data analysis show strong suppression of aerosol optical thickness outliers due to unresolved clouds and snow. At the same time, the developed filter does not reduce the aerosol retrieval capability at high 1 km resolution in strongly inhomogeneous environments, such as near centers of the active fires. Despite significant improvement, the optical depth outliers in high spatial resolution data are and will remain the problem to be addressed by the application-dependent specialized filtering techniques
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