671 research outputs found
Light propagation and fluorescence quantum yields in liquid scintillators
For the simulation of the scintillation and Cherenkov light propagation in
large liquid scintillator detectors a detailed knowledge about the absorption
and emission spectra of the scintillator molecules is mandatory. Furthermore
reemission probabilities and quantum yields of the scintillator components
influence the light propagation inside the liquid. Absorption and emission
properties are presented for liquid scintillators using 2,5-Diphenyloxazole
(PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary
wavelength shifter. New measurements of the quantum yields for various aromatic
molecules are shown.Comment: 11 pages, 3 figures, 1 tabl
Soll die Exklusivlizenz der Deutschen Post AG verlängert werden?
Der Monopolbereich der Deutschen Post AG soll, wie im Postgesetz von 1997 vorgesehen, Ende des Jahres 2002 auslaufen. Nach den jüngsten Plänen der Bundesregierung soll jedoch die völlige Deregulierung des Postmarktes auf das Jahr 2008 verschoben werden. Wie ist diese Verschiebung zu beurteilen? --
Safe liquid scintillators for large scale detectors
Many experiments in particle physics, in particular in the field of neutrino
searches, rely on organic liquid scintillators as target and detection
material. The size of these detectors was continously growing in the last
decades, up to the kiloton scale. In several cases these detectors are located
at sites with enhanced safety requirements as underground laboratories or in
the vicinity of nuclear reactors. Therefore, there is strong demand in liquids
which are safe with respect to aspects as fire protection, human health or
environmental pollution. In particular, properties as the flash point, the
vapor pressure or the toxicity need to be significantly improved as compared to
classical solvents such as xylene or pseudocumene. We present and compare the
performance and optical properties of scintillators based on high flash point
solvents. In particular polysiloxane based scintillators are characterized by
outstanding properties in terms of safety.Comment: 13 pages, 4 figure
Safe liquid scintillators for large scale detectors
Many experiments in particle physics, in particular in the field of neutrino searches, rely on organic liquid scintillators as target and detection material. The size of these detectors was continously growing in the last decades, up to the kiloton scale. In several cases these detectors are located at sites with enhanced safety requirements as underground laboratories or in the vicinity of nuclear reactors. Therefore, there is strong demand in liquids which are safe with respect to aspects as fire protection, human health or environmental pollution. In particular, properties as the flash point, the vapor pressure or the toxicity need to be significantly improved as compared to classical solvents such as xylene or pseudocumene. We present and compare the performance and optical properties of scintillators based on high flash point solvents. In particular polysiloxane based scintillators are characterized by outstanding properties in terms of safety
Meeting Clean Energy Goals Will Require the Grid of the Future
The transmission grid is the critical superhighway that connects energy supply and demand. But our grid was designed for the power plants of the past—not for the diverse range of resources and technologies of our clean energy future. Over 70 percent of the nation’s transmission infrastructure is more than 25 years old, and in many areas of the country constraints have already been an impediment to renewable power. To meet greenhouse gas reduction goals, we will need to expand electric transmission systems by 60 percent by 2030 and possibly triple the capacity of these systems by 2050. The Infl ation Reduction Act has large loan guarantees to spur grid investment, but hundreds of billions more will be eventually needed
Lazy AC-Pattern Matching for Rewriting
We define a lazy pattern-matching mechanism modulo associativity and
commutativity. The solutions of a pattern-matching problem are stored in a lazy
list composed of a first substitution at the head and a non-evaluated object
that encodes the remaining computations. We integrate the lazy AC-matching in a
strategy language: rewriting rule and strategy application produce a lazy list
of terms.Comment: In Proceedings WRS 2011, arXiv:1204.531
The relationship of alignment hyperacuity to stereopsis
Human ability to monocularly detect spatial misalignment is functionally more precise than predicted by the diameter of one foveal cone. The spatial thresholds for vernier alignment are approximately 8 to 13 arc seconds of visual angle, which is more sensitive than expected. Although threshold stereopsis (another hyperacuity) seems to be approximately double alignment hyperacuity values, studies have not conclusively shown a definite relationship to ex1st. Additionally, these measurements have not been widely tested in clinical settings. This study examines the correlation between threshold stereoacuity and the monocular alignment hyperacuity measures. Twenty six subjects were evaluated measuring threshold stereopsis with the Mentor BVAT II Visual Acuity Tester and monocular alignment hyperacuity with software designed at Pacific University College of Optometry. This study supports a relationship of sum of one standard deviation of hyperacuity data distributed for each eye with stereopsis. However, the relationship is not statistically significant, most likely due to the lack of testing precision and variability in individual performance, specifically in binocular function and appreciation of stereopsis. Increased knowledge in the areas of monocular alignment hyperacuity and threshold stereopsis may aid optometric practitioners to better understand how these two factors play a role in such clinical conditions as unexplained asthenopia, amblyopia, strabismus and stereoacuity potential. However, clinical testing of an individual patient would not seem appropriate with this testing paradigm
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Impact of Electric Industry Structure on High Wind Penetration Potential
This paper attempts to evaluate which balancing area (BA) characteristics best accommodate wind energy
On the distortion of twin building lattices
We show that twin building lattices are undistorted in their ambient group;
equivalently, the orbit map of the lattice to the product of the associated
twin buildings is a quasi-isometric embedding. As a consequence, we provide an
estimate of the quasi-flat rank of these lattices, which implies that there are
infinitely many quasi-isometry classes of finitely presented simple groups. In
an appendix, we describe how non-distortion of lattices is related to the
integrability of the structural cocycle
Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection
Over the course of several decades, organic liquid scintillators have formed
the basis for successful neutrino detectors. Gadolinium-loaded liquid
scintillators provide efficient background suppression for electron
antineutrino detection at nuclear reactor plants. In the Double Chooz reactor
antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded
scintillator is utilized for the first time. Its large scale production and
characterization are described. A new, light yield matched metal-free companion
scintillator is presented. Both organic liquids comprise the target and "Gamma
Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table
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