7,819 research outputs found
Converting environmental wastes into valuable resources
This concept employs a viable energy saving method that uses a solvent to separate oil from particle matter; it can be used in metal forming industries to deoil sludges, oxides, and particle matter that is presently committed to landfill. If oily particles are used in their oily state, severe consequences to environmental control systems such as explosions or filter blinding, occur in the air handling equipment. This is due to the presence of hydrocarbons in the stack gasses resulting from the oily particles. After deoiling, the particles can be recycled and the separated oil can be used as a fuel. The process does not produce a waste of it's own and does not harm air or water. It demonstrates the dual benefits of it being commercially viable and in the national interest of conserving resources
Maps and navigation methods
Different maps and scales are discussed with particular emphasis on their use in aviation. The author makes the observation that current navigation methods are slow and dangerous and should be replaced by scientific methods of navigation based on loxodromy and the use of the compass
Non-relativistic conformal symmetries and Newton-Cartan structures
This article provides us with a unifying classification of the conformal
infinitesimal symmetries of non-relativistic Newton-Cartan spacetime. The Lie
algebras of non-relativistic conformal transformations are introduced via the
Galilei structure. They form a family of infinite-dimensional Lie algebras
labeled by a rational "dynamical exponent", . The Schr\"odinger-Virasoro
algebra of Henkel et al. corresponds to . Viewed as projective
Newton-Cartan symmetries, they yield, for timelike geodesics, the usual
Schr\"odinger Lie algebra, for which z=2. For lightlike geodesics, they yield,
in turn, the Conformal Galilean Algebra (CGA) and Lukierski, Stichel and
Zakrzewski [alias "\alt" of Henkel], with . Physical systems realizing
these symmetries include, e.g., classical systems of massive, and massless
non-relativistic particles, and also hydrodynamics, as well as Galilean
electromagnetism.Comment: LaTeX, 47 pages. Bibliographical improvements. To appear in J. Phys.
Space-Time Noncommutativity from Particle Mechanics
We exploit the reparametrization symmetry of a relativistic free particle to
impose a gauge condition which upon quantization implies space-time
noncommutativity. We show that there is an algebraic map from this gauge back
to the standard `commuting' gauge. Therefore the Poisson algebra, and the
resulting quantum theory, are identical in the two gauges. The only difference
is in the interpretation of space-time coordinates. The procedure is repeated
for the case of a coupling with a constant electromagnetic field, where the
reparametrization symmetry is preserved. For more arbitrary interactions, we
show that standard dynamical system can be rendered noncommutative in space and
time by a simple change of variables.Comment: 13 p
Chiral fermions as classical massless spinning particles
Semiclassical chiral fermion models with Berry term are studied in a
symplectic framework. In the free case, the system can be obtained from
Souriau's model for a relativistic massless spinning particle by "enslaving"
the spin. The Berry term is identified with the classical spin two-form of the
latter model. The Souriau model carries a natural Poincar\'e symmetry that we
highlight, but spin enslavement breaks the boost symmetry. However the relation
between the models allows us to derive a Poincare symmetry of unconventional
form for chiral fermions. Then we couple our system to an external
electromagnetic field. For gyromagnetic ratio we get curious superluminal
Hall-type motions; for and in a pure constant magnetic field in
particular, we find instead spiraling motions.Comment: Substantially revised and extended version. 31 pages, 5 figures.
Details clarified and references added. To be published in PR
Anyons with anomalous gyromagnetic ratio & the Hall effect
Letting the mass depend on the spin-field coupling as
, we propose a new set of
relativistic planar equations of motion for spinning anyons. Our model can
accommodate any gyromagnetic ratio and provides us with a novel version of
the Bargmann-Michel-Telegdi equations in 2+1 dimensions. The system becomes
singular when the field takes a critical value, and, for , the only
allowed motions are those which satisfy the Hall law. For each a
secondary Hall effect arises also for another critical value of the field. The
non-relativistic limit of our equations yields new models which generalize our
previous ``exotic'' model, associated with the two-fold central extension of
the planar Galilei group.Comment: The affiliation of the first author's Institution is presented in
detail. LaTeX, 12 pages no figures. To appear in Phys. Lett.
Representations of the conformal Lie algebra in the space of tensor densities on the sphere
Let be the space of tensor densities on
of degree . We consider this space as an induced module
of the nonunitary spherical series of the group and
classify -sim{\mathcal F}_\lambda(\mathbb{S}^n)\lambda$.Comment: Published by JNMP at http://www.sm.luth.se/math/JNMP
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