9,326 research outputs found
Progress on the Ohio State University Get Away Special G-0318: DEAP
The Get Away Special program became a major presence at the Ohio State University with the award of GAS-0318 by the American Institute of Aeronautics and Astronautics. There are some twenty engineering researchers and students currently working on the project. GAS-0318 payload is an experimental manufacturing process known as Directional Electrostatic Accretion Process (DEAP). This high precision portable microgravity manufacturing method will revolutionize the manufacture and repair of spacecraft and space structures. The cost effectiveness of this process will be invaluable to future space development and exploration
Air-core photonic band-gap fibers: the impact of surface modes
We study the dispersion and leakage properties for the recently reported
low-loss photonic band-gap fiber by Smith et al. [Nature 424, 657 (2003)]. We
find that surface modes have a significant impact on both the dispersion and
leakage properties of the fundamental mode. Our dispersion results are in
qualitative agreement with the dispersion profile reported recently by Ouzounov
et al. [Science 301, 1702 (2003)] though our results suggest that the observed
long-wavelength anomalous dispersion is due to an avoided crossing (with
surface modes) rather than band-bending caused by the photonic band-gap
boundary of the cladding.Comment: 7 pages including 4 figures. Accepted for Optics Expres
Interfacial tension in water at solid surfaces
A model for the formation of cavitation nuclei in liquids has recently been
presented with basis in interfacial liquid tension at non-planar solid surfaces
of concave form. In the present paper investigations of water-solid interfaces
by atomic force microscopy are reported to illuminate experimentally effects of
interfacial liquid tension. The results support that such tension occurs and
that voids develop at solid-liquid interfaces.Comment: RevTeX, 5 pages including 8 figure
Taxes, Subsidies and Equilibrium Labor Market Outcomes
We explore the effects of taxes and subsidies on job creation, job destruction, employment, and wages in the Mortensen-Pissarides version of the search and matching equilibrium framework. Qualitative analytical results show that wage and employment subsidies increase employment, especially of low skill workers, and also increase wages. A job creation or hiring subsidy reduces unemployment duration but increases incidence with an ambiguous effect on overall employment. A firing tax has the reverse effects but the same indeterminacy. In the special case of a competitive search equilibrium, the one in which search externalities are internalized, there is a first best configuration: no tax on the wage, an employment subsidy that offsets the distortions on the job destruction margin induced by unemployment compensation and employment protection policy, and a hiring subsidy equal to the implicit tax on severance imposed by any form of employment protection, with the costs of these and other policies financed by a non-distortionary consumption tax. Computational experiments confirm this ideal also determines the direction in which marginal improvements can be made both in terms of efficiency and in terms of improving low skill worker employment and wage outcomes.
Size-dependent nonlocal effects in plasmonic semiconductor particles
Localized surface plasmons (LSP) in semiconductor particles are expected to
exhibit spatial nonlocal response effects as the geometry enters the nanometer
scale. To investigate these nonlocal effects, we apply the hydrodynamic model
to nanospheres of two different semiconductor materials: intrinsic InSb and
-doped GaAs. Our results show that the semiconductors indeed display
nonlocal effects, and that these effects are even more pronounced than in
metals. In a InSb particle at , the LSP
frequency is blueshifted 35%, which is orders of magnitude larger than the
blueshift in a metal particle of the same size. This property, together with
their tunability, makes semiconductors a promising platform for experiments in
nonlocal effects.Comment: 7 pages, 3 figures, 1 table, corrected typos in text and figure
Slow-light enhancement of Beer-Lambert-Bouguer absorption
We theoretically show how slow light in an optofluidic environment
facilitates enhanced light-matter interactions, by orders of magnitude. The
proposed concept provides strong opportunities for improving existing
miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption
measurements widely employed in analytical chemistry.Comment: 4 pages including 4 figures. Accepted for AP
Mode-Field Radius of Photonic Crystal Fibers Expressed by the V-parameter
We numerically calculate the equivalent mode-field radius of the fundamental
mode in a photonic crystal fiber (PCF) and show that this is a function of the
V-parameter only and not the relative hole size. This dependency is similar to
what is found for graded-index standard fibers and we furthermore show that the
relation for the PCF can be excellently approximated with the same general
mathematical expression. This is to our knowledge the first semi-analytical
description of the mode-field radius of a PCF.Comment: Accepted for Opt. Let
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