29,293 research outputs found
Mapping the train model for earthquakes onto the stochastic sandpile model
We perform a computational study of a variant of the ``train'' model for
earthquakes [PRA 46, 6288 (1992)], where we assume a static friction that is a
stochastic function of position rather than being velocity dependent. The model
consists of an array of blocks coupled by springs, with the forces between
neighbouring blocks balanced by static friction. We calculate the probability,
P(s), of the occurrence of avalanches with a size s or greater, finding that
our results are consistent with the phenomenology and also with previous models
which exhibit a power law over a wide range. We show that the train model may
be mapped onto a stochastic sandpile model and study a variant of the latter
for non-spherical grains. We show that, in this case, the model has critical
behaviour only for grains with large aspect ratio, as was already shown in
experiments with real ricepiles. We also demonstrate a way to introduce
randomness in a physically motivated manner into the model.Comment: 14 pages and 6 figures. Accepted in European Physical Journal
Self-Similar Collapse of Scalar Field in Higher Dimensions
This paper constructs continuously self-similar solution of a spherically
symmetric gravitational collapse of a scalar field in n dimensions. The
qualitative behavior of these solutions is explained, and closed-form answers
are provided where possible. Equivalence of scalar field couplings is used to
show a way to generalize minimally coupled scalar field solutions to the model
with general coupling.Comment: RevTex 3.1, 15 pages, 3 figures; references adde
Structural and insulator-to-metal phase transition at 50 GPa in GdMnO3
We present a study of the effect of very high pressure on the orthorhombic
perovskite GdMnO3 by Raman spectroscopy and synchrotron x-ray diffraction up to
53.2 GPa. The experimental results yield a structural and insulator-to-metal
phase transition close to 50 GPa, from an orthorhombic to a metrically cubic
structure. The phase transition is of first order with a pressure hysteresis of
about 6 GPa. The observed behavior under very high pressure might well be a
general feature in rare-earth manganites.Comment: 4 pages, 3 figures and 2 table
The mathematical description of the electrosynthesis of composites of oxy-hydroxycompounds cobalt with polypyrrole overooxidazed
The electrosynthesis of the composite with of the overoxidized polypyrrole with cobalt oxy-hydroxide in strongly acidic media has been described mathematically, using linear stability theory and bifurcation analysis. The steadystates stability conditions and oscillatory and monotonic instability requirements have been described too. The system´s behavior was compared with behavior of other systems with overoxidation, electropolymerization of heterocyclic compounds and electrosynthesis of the cobalt oxy-hydroxides
Efeito de diferentes sistemas de aquecimento no desempenho de leitoes.
bitstream/item/59001/1/CUsersPiazzonDocuments122.pd
How does authentic leadership boost work engagement? Exploring the mediating role of work meaningfulness and work–family enrichment
Leadership is crucial in organizational life. Positive leadership is marked by transparent, trust-based leader–follower relationships that significantly boost employees’ dedication and engagement. Work engagement stems from a positive bond between workers, their job, and their organization. Authentic leadership, in particular, has been found to enhance work engagement, but this relationship is quite complex. Prior studies have explored the psychological processes linking organizational context and work-related attitudes and provided intriguing insights, such as that employees consider work to be part of their identity and that positive work experiences enrich family life. This research more closely examined authentic leadership’s impact on work engagement, including the mediating effect of meaningful work and work–family enrichment. A cross-sectional study was conducted with data from various organizations’ employees (number = 292). Multiple regression analyses’ results support the theoretical model, confirming a significant positive link between perceived authentic leadership and work engagement. These variables are directly and indirectly related through the proposed mediators. Implications for human resource management are discussed, especially strategies that increase work environments’ positive impacts on work engagement.info:eu-repo/semantics/publishedVersio
Study of the Fully Frustrated Clock Model using the Wang-Landau Algorithm
Monte Carlo simulations using the newly proposed Wang-Landau algorithm
together with the broad histogram relation are performed to study the
antiferromagnetic six-state clock model on the triangular lattice, which is
fully frustrated. We confirm the existence of the magnetic ordering belonging
to the Kosterlitz-Thouless (KT) type phase transition followed by the chiral
ordering which occurs at slightly higher temperature. We also observe the lower
temperature phase transition of KT type due to the discrete symmetry of the
clock model. By using finite-size scaling analysis, the higher KT temperature
and the chiral critical temperature are respectively estimated as
and . The results are in favor of the double
transition scenario. The lower KT temperature is estimated as .
Two decay exponents of KT transitions corresponding to higher and lower
temperatures are respectively estimated as and
, which suggests that the exponents associated with the KT
transitions are universal even for the frustrated model.Comment: 7 pages including 9 eps figures, RevTeX, to appear in J. Phys.
The low dimensional dynamical system approach in General Relativity: an example
In this paper we explore one of the most important features of the Galerkin
method, which is to achieve high accuracy with a relatively modest
computational effort, in the dynamics of Robinson-Trautman spacetimes.Comment: 7 pages, 5 figure
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