5,729 research outputs found
Gamma-rays from the compact colliding wind region in Cyg OB2 #5
In this contribution we model the non-thermal emission (from radio to
gamma-rays) produced in the compact (and recently detected) colliding wind
region in the multiple stellar system Cyg OB2 #5. We focus our study on the
detectability of the produced gamma-rays.Comment: To appear in the proceedings of the 5th International Symposium on
High-Energy Gamma-Ray Astronomy (Gamma2012), held in Heidelberg, July 9-13,
201
Permanent Magnet Display System
Pacemakers can malfunction when exposed to high magnetic fields. This becomes especially problematic for patients with pacemakers who need MRI scans as MRI machines can subject the pacemaker to damaging magnetic fields. St.Jude Medical, one of the leading biotech companies, is working to make their pacemakers MRI-safe. In order to test their MRI-safe pacemaker designs, they need an automated test apparatus that will collect and report the magnetic field the pacemaker is being exposed to. This report describes the design of such a test system that reads the Tesla intensity the pacemaker is exposed to and wirelessly transmits the data outside the testing room where the data can be viewed and evaluated
Local quanta, unitary inequivalence, and vacuum entanglement
In this work we develop a formalism for describing localised quanta for a
real-valued Klein-Gordon field in a one-dimensional box . We quantise
the field using non-stationary local modes which, at some arbitrarily chosen
initial time, are completely localised within the left or the right side of the
box. In this concrete set-up we directly face the problems inherent to a notion
of local field excitations, usually thought of as elementary particles.
Specifically, by computing the Bogoliubov coefficients relating local and
standard (global) quantizations, we show that the local quantisation yields a
Fock space which is unitarily inequivalent to the standard one
. In spite of this, we find that the local creators and
annihilators remain well defined in the global Fock space , and
so do the local number operators associated to the left and right partitions of
the box. We end up with a useful mathematical toolbox to analyse and
characterise local features of quantum states in . Specifically,
an analysis of the global vacuum state in terms
of local number operators shows, as expected, the existence of entanglement
between the left and right regions of the box. The local vacuum
, on the contrary, has a very different character.
It is neither cyclic nor separating and displays no entanglement. Further
analysis shows that the global vacuum also exhibits a distribution of local
excitations reminiscent, in some respects, of a thermal bath. We discuss how
the mathematical tools developed herein may open new ways for the analysis of
fundamental problems in local quantum field theory.Comment: 28 pages, 8 figure
EL CONTEXTO SOCIAL Y EL CAMBIO TIPOLÓGICO Y TECNOLÓGICO EN EL DISEÑO DE LAS VIVIENDAS IRREGULARES EN EL ÁREA NATURAL PROTEGIDA DEL PARQUE NACIONAL DEL NEVADO DE TOLUCA: CASO DE ESTUDIO, RAÍCES Y LOMA ALTA
Como una alternativa al análisis del deterioro del ambiente y la reducción de los recursos naturales, este artículo presenta un criterio metodológico para explicar, cómo el cambio tipológico y tecnológico de las viviendas irregulares, han establecido el detrimento del medio ambiente, así mismo, se muestra cómo se ha generado la pérdida del bosque
Amphibious NDT Robots
Oil, petrochemical, and food processing industries worldwide store their raw materials and product in tens of thousands of storage tanks. The tanks are mostly constructed using
welded steel plates and therefore subject to corrosion and weld cracking. Testing the structural integrity of these storage tanks with non-destructive testing (NDT) techniques is an expensive and time consuming activity. The walls of a large tank can usually be tested manually (for corrosion thinning and weld defects using ultrasonic techniques) from outside
the tank. Access to most areas of a wall is obtained by constructing scaffolding or abseiling down from the top. However, erecting scaffolding is expensive and the inspection is tedious and slow. These costs can be reduced and the inspection speeded up by using climbing robots that deploy ultrasonic probes with scanning arms
Neotectonic uplift of the Pacific Coast of Panama and Costa Rica, based on benthic foraminifera
Abstrac
Prototipo de vivienda de adobe con energías renovables: caso de estudio localidad de Raíces, Área Natural Protegida del Parque Nacional del Nevado de Toluca, Estado de México
Como una alternativa a la construcción de la vivienda, este artículo introduce una nueva tecnología para edificar un prototipo de casa de adobe con energías renovables. Se muestrauna metodología para su diseño que se establece a partir de las características de las viviendas de la localidad de Raíces, ubicada en el municipio de Zinacantepec, dentro del territorio del Parque Nacional del Nevado de Toluca, espacio natural protegido por Decreto en 1936
- …