642 research outputs found
Generalized Green'S Equivalences on the Subsemigroups of the Bicyclic Monoid
We study generalized Green's equivalences on all subsemigroups of the bicyclic monoid B and determine the abundant (and adequate) subsemigroups of B. © 2010 Copyright Taylor and Francis Group, LLC
Developing the Technique of Measurements of Magnetic Field in the CMS Steel Yoke Elements With Flux-Loops and Hall Probes
Compact muon solenoid (CMS) is a general-purpose detector designed to run at
the highest luminosity at the CERN large hadron collider (LHC). Its distinctive
features include a 4 T superconducting solenoid with 6 m diameter by 12.5 m
long free bore, enclosed inside a 10000-ton return yoke made of construction
steel. Accurate characterization of the magnetic field everywhere in
theCMSdetector, including the large ferromagnetic parts of the yoke, is
required. To measure the field in and around ferromagnetic parts, a set of
flux-loops and Hall probe sensors will be installed on several of the steel
pieces. Fast discharges of the solenoid during system commissioning tests will
be used to induce voltages in the flux-loops that can be integrated to measure
the flux in the steel at full excitation of the solenoid. The Hall sensors will
give supplementary information on the axial magnetic field and permit
estimation of the remanent field in the steel after the fast discharge. An
experimental R&D program has been undertaken, using a test flux-loop, two Hall
sensors, and sample disks made from the same construction steel used for the
CMS magnet yoke. A sample disc, assembled with the test flux-loop and the Hall
sensors, was inserted between the pole tips of a dipole electromagnet equipped
with a computer-controlled power supply to measure the excitation of the steel
from full saturation to zero field. The results of the measurements are
presented and discussed.Comment: 6 pages, 8 figures, 6 reference
Ultra-compact optical auto-correlator based on slow-light enhanced third harmonic generation in a silicon photonic crystal waveguide
The ability to use coherent light for material science and applications is
directly linked to our ability to measure short optical pulses. While
free-space optical methods are well-established, achieving this on a chip would
offer the greatest benefit in footprint, performance, flexibility and cost, and
allow the integration with complementary signal processing devices. A key goal
is to achieve operation at sub-Watt peak power levels and on sub-picosecond
timescales. Previous integrated demonstrations require either a temporally
synchronized reference pulse, an off-chip spectrometer, or long tunable delay
lines. We report the first device capable of achieving single-shot time-domain
measurements of near-infrared picosecond pulses based on an ultra-compact
integrated CMOS compatible device, with the potential to be fully integrated
without any external instrumentation. It relies on optical third-harmonic
generation in a slow-light silicon waveguide. Our method can also serve as a
powerful in-situ diagnostic tool to directly map, at visible wavelengths, the
propagation dynamics of near-infrared pulses in photonic crystals.Comment: 20 pages, 6 figures, 38 reference
Construction des caustiques par réflexion sur les courbes planes, le point lumineux étant dans le plan de la courbe
Sur les exponentielles successives d'Euler et les logarithmes des différents ordres des nombres
"Outside, it is snowing": Experience and finitude in the nonrepresentational landscapes of Alain Robbe-Grillet
Copyright © 2008 PionRomanillos J L, 2008. The definitive, peer-reviewed and edited version of this article is published in Environment and Planning D: Society and Space 26(5) 795 â 822 DOI: 10.1068/d6207This paper presents and explicates the anonymous and impersonal spatialities tentatively mapped in the novels of Alain Robbe-Grillet. Emerging from the kinds of landscapes and visualities articulated, these spatialities are at odds with the kind of anthropocentrism characteristic of phenomenological narratives of spatial experience that would start from an apparently stable human-subject position. It is argued that his body of literature dismantles the anthropocentric narratives and biographies that would produce in both the space of the world and the âphenomenological subjectâ an unwarranted depth and naturalism. Importantly, and reflecting the theoretical turn towards the being of language, Robbe-Grillet questions the legitimacy of linguistic subjects to capture the spaces of the visible. As such, it is argued that his literature reflects an experience of the critiques of phenomenology. Importantly, this âcritiqueâ goes hand in hand with the kinds of spatialities and landscapes that are rendered in the novelsâthe indefinite perspectives they open up, the paradoxical visualities they sustain or deny, and the disorientation they inject into the heart of spatial experience. These literary effects produce a nonanthropocentric and nonpersonal spatiality which, although contributing to an erasure of the âsubjectâ, at the same time expose and open up a sociospatiality based on singularities, intensities, and finitude
Black flies (Diptera: Simuliidae) of French Guiana: cytotaxonomy and a preliminary list of species
3D Magnetic Analysis of the CMS Magnet
The CMS magnetic system consists of a super-conducting solenoid coil, 12.5 m
long and 6 m free bore diameter, and of an iron flux-return yoke, which
includes the central barrel, two end-caps and the ferromagnetic parts of the
hadronic forward calorimeter. The magnetic flux density in the center of the
solenoid is 4 T. To carry out the magnetic analysis of the CMS magnetic system,
several 3D models were developed to perform magnetic field and force
calculations using the Vector Fields code TOSCA. The analysis includes a study
of the general field behavior, the calculation of the forces on the coil
generated by small axial, radial displacements and angular tilts, the
calculation of the forces on the ferromagnetic parts, the calculation of the
fringe field outside the magnetic system, and a study of the field level in the
chimneys for the current leads and the cryogenic lines. A procedure to
reconstruct the field inside a cylindrical volume starting from the values of
the magnetic flux density on the cylinder surface is considered. Special
TOSCA-GEANT interface tools have being developed to input the calculated
magnetic field into the detector simulation package.Comment: 4 pages, 6 figures, 1 equation, 14 reference
- âŠ