4,839 research outputs found
Nonholonomic constraints in -symplectic Classical Field Theories
A -symplectic framework for classical field theories subject to
nonholonomic constraints is presented. If the constrained problem is regular
one can construct a projection operator such that the solutions of the
constrained problem are obtained by projecting the solutions of the free
problem. Symmetries for the nonholonomic system are introduced and we show that
for every such symmetry, there exist a nonholonomic momentum equation. The
proposed formalism permits to introduce in a simple way many tools of
nonholonomic mechanics to nonholonomic field theories.Comment: 27 page
A semi-infinite matrix analysis of the BFKL equation
The forward BFKL equation is discretised in virtuality space and it is shown
that the diffusion into infrared and ultraviolet momenta can be understood in
terms of a semi-infinite matrix. The square truncation of this matrix can be
exponentiated leading to asymptotic eigenstates sharing many features with the
BFKL gluon Green's function in the limit of large matrix size. This truncation
is closely related to a representation of the XXX Heisenberg spin chain with SL(2) invariance where the Hamiltonian acts on a
symmetric double copy of the harmonic oscillator. A simple modification of the
BFKL matrix suppressing the infrared modes generates evolution with energy
compatible with unitarity.Comment: Small changes, same conclusions, matching the published version in
EPJ
Relationship between the Mathematical Quotient and Emotional Quotient as a Driven Factor to Improve the Social Profile Characteristics of Students
This study investigated the profile, emotional and mathematical quotients of 323 college students in
the Philippines. The researcher gathered the data through the EQ Map questionnaire and Scholastic
Ability Test for Adults. Results indicated that the respondents' emotional quotient level is moderately
well, and their mathematical quotient is poor. Results also showed that the number of hours studying
their lesson among the respondents' profile variables affect their emotional quotient. On the other
hand, the place where respondents learn their lessons affects their mathematical quotient. This study
also signified that the mathematical quotient has no significant relationship to the emotional quotient.
This study can show students how social profile characteristics influence their emotional and
mathematical quotients. It is recommended that a local study be conducted to evaluate whether or not
there is a substantial association between students' emotional quotients and their academic
achievement. The results of this study might then be concluded. In addition, a study on the factors
affecting the emotional and mathematical capacity of the student may also be undertaken in a specific
group within the institution, and the results may then be compared to those obtained from studies
conducted at other universities. In a similar sense, it is also recommended to carry out research that
will serve the needs of both private and government institutions regarding the aspects that influence
emotional intelligence
On the Hamilton-Jacobi Theory for Singular Lagrangian Systems
We develop a Hamilton-Jacobi theory for singular lagrangian systems using the
Gotay-Nester-Hinds constraint algorithm. The procedure works even if the system
has secondary constraints.Comment: 36 page
Symmetries in Classical Field Theory
The multisymplectic description of Classical Field Theories is revisited,
including its relation with the presymplectic formalism on the space of Cauchy
data. Both descriptions allow us to give a complete scheme of classification of
infinitesimal symmetries, and to obtain the corresponding conservation laws.Comment: 70S05; 70H33; 55R10; 58A2
Hamiltonian Dynamics of Linearly Polarized Gowdy Models Coupled to Massless Scalar Fields
The purpose of this paper is to analyze in detail the Hamiltonian formulation
for the compact Gowdy models coupled to massless scalar fields as a necessary
first step towards their quantization. We will pay special attention to the
coupling of matter and those features that arise for the three-handle and
three-sphere topologies that are not present in the well studied three torus
case -in particular the polar constraints that come from the regularity
conditions on the metric. As a byproduct of our analysis we will get an
alternative understanding, within the Hamiltonian framework, of the appearance
of initial and final singularities for these models.Comment: Final version to appear in Classical and Quantum Gravit
A Generalization of Chetaev's Principle for a Class of Higher Order Non-holonomic Constraints
The constraint distribution in non-holonomic mechanics has a double role. On
one hand, it is a kinematic constraint, that is, it is a restriction on the
motion itself. On the other hand, it is also a restriction on the allowed
variations when using D'Alembert's Principle to derive the equations of motion.
We will show that many systems of physical interest where D'Alembert's
Principle does not apply can be conveniently modeled within the general idea of
the Principle of Virtual Work by the introduction of both kinematic constraints
and variational constraints as being independent entities. This includes, for
example, elastic rolling bodies and pneumatic tires. Also, D'Alembert's
Principle and Chetaev's Principle fall into this scheme. We emphasize the
geometric point of view, avoiding the use of local coordinates, which is the
appropriate setting for dealing with questions of global nature, like
reduction.Comment: 27 pages. Journal of Mathematical Physics (to zappear
Morphological Characterization of Brazilian Organ Clays Using AFM and SEM Studies
A combination of SEM (Scanning Electron Microscopy) and AFM (Atomic Force Microscopy) techniques was used to characterise the morphology of Brazilian montmorillonites before and after intercalation of some organic compounds. AFM revealed that the layers are staked over above the others. The surface of the particles consisted of layers bounded with smooth flat basal planes and larger edges ending in some cascade-like steps 184 µm wide. Some micro and macro valleys (0.6 µm deep) are distributed throughout the whole area and irregularities on basal planes may be attributed to the crystallographic conditions of the genesis of these Brazilian montmorillonites. The mapping performed over 20 x 40 areas showed adhesion forces of 11 nN magnitude on bare clay mineral in the Na+ form and 40 nN for the calcium form. Forces between 10 and 6 nN were found after organic intercalation. In general, the intercalation caused significant changes in the surface properties of clay mineral. The combination of AFM and SEM studies provided evidence about the poorl crystallinity of the Brazilian montmorillonites.A combination of SEM (Scanning Electron Microscopy) and AFM (Atomic Force Microscopy) techniques was used to characterise the morphology of Brazilian montmorillonites before and after intercalation of some organic compounds. AFM revealed that the layers are staked over above the others. The surface of the particles consisted of layers bounded with smooth flat basal planes and larger edges ending in some cascade-like steps 184 µm wide. Some micro and macro valleys (0.6 µm deep) are distributed throughout the whole area and irregularities on basal planes may be attributed to the crystallographic conditions of the genesis of these Brazilian montmorillonites. The mapping performed over 20 x 40 areas showed adhesion forces of 11 nN magnitude on bare clay mineral in the Na+ form and 40 nN for the calcium form. Forces between 10 and 6 nN were found after organic intercalation. In general, the intercalation caused significant changes in the surface properties of clay mineral. The combination of AFM and SEM studies provided evidence about the poorl crystallinity of the Brazilian montmorillonites
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