14,242 research outputs found
Stress waves in transversely isotropic media: The homogeneous problem
The homogeneous problem of stress wave propagation in unbounded transversely isotropic media is analyzed. By adopting plane wave solutions, the conditions for the existence of the solution are established in terms of phase velocities and directions of particle displacements. Dispersion relations and group velocities are derived from the phase velocity expressions. The deviation angles (e.g., angles between the normals to the adopted plane waves and the actual directions of their propagation) are numerically determined for a specific fiber-glass epoxy composite. A graphical method is introduced for the construction of the wave surfaces using magnitudes of phase velocities and deviation angles. The results for the case of isotropic media are shown to be contained in the solutions for the transversely isotropic media
WIRIS OM tools: a semantic formula editor
With the increasing reliance on computers for the automatic processing
of information a new method is needed for editing mathematical formulae.
We are used to WYSIWYG editors that produce beautiful presentations of
formulae and store the typesetting primitives rather than the meaning of the
formulas. However, new services such as database searching or calculation
web-services work best if they have access to the semantic information behind
a formula. This can only be done with a new generation of formula editors.
In this paper we present WIRIS OM Tools [17], a semantic oriented formula
editor which addresses these concerns. It is based on the OpenMath language
and a suitable transformation process between OpenMath and MathML ex-
pressions. Additionally, this approach adds new features for the users such
as error, type and syntax checking. The editor is currently being used in the
LeActiveMath and WebALT projects
Seismic diagnostics for transport of angular momentum in stars 2. Interpreting observed rotational splittings of slowly-rotating red giant stars
Asteroseismology with the space-borne missions CoRoT and Kepler provides a
powerful mean of testing the modeling of transport processes in stars.
Rotational splittings are currently measured for a large number of red giant
stars and can provide stringent constraints on the rotation profiles. The aim
of this paper is to obtain a theoretical framework for understanding the
properties of the observed rotational splittings of red giant stars with slowly
rotating cores. This allows us to establish appropriate seismic diagnostics for
rotation of these evolved stars. Rotational splittings for stochastically
excited dipolar modes are computed adopting a first-order perturbative approach
for two benchmark models assuming slowly rotating cores. For red
giant stars with slowly rotating cores, we show that the variation of the
rotational splittings of modes with frequency depends only on the
large frequency separation, the g-mode period spacing, and the ratio of the
average envelope to core rotation rates (). This leds us to propose a
way to infer directly from the observations. This method is
validated using the Kepler red giant star KIC 5356201. Finally, we provide a
theoretical support for the use of a Lorentzian profile to measure the observed
splittings for red giant stars.Comment: 15 pages, 15 figures, accepted for publication in A&
Interaction-induced topological properties of two bosons in flat-band systems
In flat-band systems, destructive interference leads to the localization of
non-interacting particles and forbids their motion through the lattice.
However, in the presence of interactions the overlap between neighbouring
single-particle localized eigenstates may enable the propagation of bound pairs
of particles. In this work, we show how these interaction-induced hoppings can
be tuned to obtain a variety of two-body topological states. In particular, we
consider two interacting bosons loaded into the orbital angular momentum
states of a diamond-chain lattice, wherein an effective flux may yield a
completely flat single-particle energy landscape. In the weakly-interacting
limit, we derive effective single-particle models for the two-boson
quasiparticles which provide an intuitive picture of how the topological states
arise. By means of exact diagonalization calculations, we benchmark these
states and we show that they are also present for strong interactions and away
from the strict flat-band limit. Furthermore, we identify a set of doubly
localized two-boson flat-band states that give rise to a special instance of
Aharonov-Bohm cages for arbitrary interactions
O mini-cavalo (Equus caballus) puruca da ilha de MarajĂł - Brasil.
O mini-cavalo Puruca em conservação no BAGAM - Banco de Germoplasma Animal da AmazĂ´nia Oriental constitui uma pequena população, sendo resultado do cruzamento do cavalo Marajoara com o pĂ´nei da raça francesa ?Shetland?, que foi selecionado atĂ© atingir a altura padrĂŁo de 1,18m. A Associação Brasileira de Criadores da Raça Puruca ? ABCRP cita que a raça possui inĂşmeras caracterĂsticas morfolĂłgicas que o tornam um grupo diferenciado. Os animais sĂŁo criados em Salvaterra, ilha de MarajĂł, PA. Os descritores estudados sĂŁo: Altura da Cernelha (AC), Altura do Dorso (AD), Altura da Garupa (AG), Altura de Costados (ACo), Comprimento da Cabeça (CCa), Comprimento do Pescoço (CP), Comprimento Dorso-Lombo (CDL), Comprimento da Garupa (CG), Comprimento da Espádua (CE), Comprimento do Corpo (CC), Largura da Cabeça (LC), Largura do Peito (LP), Largura das Ancas (LA), PerĂmetro do TĂłrax (PT) e PerĂmetro da Canela (PC), alĂ©m dos pesos nas idades padrões. A raça, com base em marcadores microssatĂ©lites, Ă© uma variedade da raça Marajoara, em função de cruzamentos entre os dois grupos genĂ©ticos e seleção para o menor porte. Este trabalho apresenta resultados parciais dos principais descritores, alĂ©m de avaliar o comportamento e o desempenho da raça em conservação
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