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Process Control of 3D Welding as a Droplet-Based Rapid Prototyping Technique
Three-dimensional welding is investigated as a rapid prototyping technique for the production
of real Inetallic parts using gas metal arc welding principles. A high speed machine vision
system is used to study the correlation between droplet transfer parameters and resultant weld
penetration characteristics. Experimental work is conducted to determine how droplet transfer
frequency, droplet size, and number of passes affect the geometrical and Inetallurgical properties
ofthe weld penetration. A finite element analysis is performed in order to study what influence
additional layering has on the cooling characteristics and resultant penetration profile.Mechanical Engineerin
Measuring the Impact of Regulationon Market Stability: Evidence from the US Markets
In this paper, we introduce a new methodology designed to test the effect of new regulatory disclosure requirements on the disclosure threshold as predicted by the extant literature (Verrecchia (1983), Dye (1985)). We apply our methodology to test the consistency between observed effects from major US regulation past and present (1933/1934 Securities Acts, Regulation Fair Disclosure 2000, and the Sarbanes-Oxley Act 2002) with regulatory objectives.
The Effectiveness of Britain's Financial Service Authority: An Economic Analysis
Sweeping regulatory reforms in Britain resulted in the formation of the Financial Services Authority (FSA). Because greater transparency of information is a major objective for this Act, shifting from one information system to another has re-distributive effects. We identify these effects at a sector level and their drivers at the firm level. At a sector level, FSA has generally increased the precision of investorsâ priors reducing the information risk component of the cost of capital. At a firm level, large firms act as âStackelberg leadersâ in voluntary disclosure games. FSA regulation shifts power from leaders to âfollowersâ.Disclosure, Regulation, Game Theory, Stackelberg Leader, Cost of Capital: information asymmetry
The Financial Services Reform Act 2001: Impact on Systemic risk in Australia
The rise of conglomerate banks and their interrelated balance sheets, pose new challenges to theories of financial regulation. We measure the impact of recent legislative changes in Australia upon systemic risk, for banking and near banking sectors, and demonstrate a significant reduction post the legislation. This is consistent with a major legislative goal, to promote global competitiveness, because it implies a reduction in the cost of equity capital. In addition, we find no evidence in support of the HIH collapse increasing systemic risk in the overall financial sector but a relatively small effect was detected in the banking sector.Ris, Banks, Disclosure, Regulation, Entropy
On the Margins of Sustainability. Prehistoric Settlement of Utrok Atoll, Northern Marshall Islands (Review)
On the Margins of Sustainability. Prehistoric Settlement of Utrok Atoll, Northern Marshall Islands
Marshall I. Weisler BAR International Series 967, Archaeopress, Oxford. 2001.
144 pp. (122 B&W figures, photographs, maps and drawings, 24 tables, 3 appendices) ÂŁ28.00 (US$40.00), paper. ISBN 1-84171-254-X
Review by Felicia R. Beardsley, Ph.D.</p
A Correlation Between Changes in Solar Luminosity and Differential Radius Measurements
Solar luminosity variations occurring during solar cycle 21 can be attributed in large part to the presence of sunspots and faculae. Nevertheless, there remains a residual portion of the luminosity variation distinctly unaccounted for by these phenomena of solar activity. At the Santa Catalina Laboratory for Experimental Relativity by Astrometry (SCLERA), observations of the solar limb are capable of detecting changes in the solar limb darkening function by monitoring a quantity known as the differential radius. These observations are utilized in such a way that the effects of solar activity are minimized in order to reveal the more fundamental structure of the photosphere. The results of observations made during solar cycle 21 at various solar latitudes indicate that a measurable change did occur in the global photospheric limb darkening function. It is proposed that the residual luminosity change is associated in part with this change in limb darkening
Simulation of aromatic SOA formation using the lumping model integrated with explicit gas-phase kinetic mechanisms and aerosol-phase reactions
The Unified Partitioning-Aerosol phase Reaction (UNIPAR) model has been
developed to predict the secondary organic aerosol (SOA) formation through
multiphase reactions. The model was evaluated with aromatic SOA data produced
from the photooxidation of toluene and 1,3,5-trimethylbenzene (135-TMB) under
various concentrations of NO<sub>x</sub> and SO<sub>2</sub> using an outdoor
reactor (University of Florida Atmospheric PHotochemical Outdoor Reactor
(UF-APHOR) chamber). When inorganic species (sulfate, ammonium and water)
are present in aerosol, the prediction of both toluene SOA and 135-TMB SOA,
in which the oxygen-to-carbon (O : C) ratio is lower than 0.62, are approached
under the assumption of a complete organic/electrolyte-phase separation below
a certain relative humidity. An explicit gas-kinetic model was employed to
express gas-phase oxidation of aromatic hydrocarbons. Gas-phase products are
grouped based on their volatility (6 levels) and reactivity (5 levels) and
exploited to construct the stoichiometric coefficient (α<sub>i,j</sub>)
matrix, the set of parameters used to describe the concentrations of organic
compounds in multiphase. Weighting of the α<sub>i,j</sub> matrix as a function
of NO<sub>x</sub> improved the evaluation of NO<sub>x</sub> effects on aromatic
SOA. The total amount of organic matter (OM<sub>T</sub>) is predicted by two modules
in the UNIPAR model: OM<sub>P</sub> by a partitioning process and OM<sub>AR</sub> by
aerosol-phase reactions. The OM<sub>AR</sub> module predicts multiphase reactions of
organic compounds, such as oligomerization, acid-catalyzed reactions, and
organosulfate (OS) formation. The model reasonably simulates SOA formation
under various aerosol acidities, NO<sub>x</sub> concentrations, humidities and
temperatures. Furthermore, the OS fractions in the SOA predicted by the model
were in good agreement with the experimentally measured OS fractions
The FHD/ppsilon Epoch of Reionization Power Spectrum Pipeline
Epoch of Reionization data analysis requires unprecedented levels of accuracy
in radio interferometer pipelines. We have developed an imaging power spectrum
analysis to meet these requirements and generate robust 21 cm EoR measurements.
In this work, we build a signal path framework to mathematically describe each
step in the analysis, from data reduction in the FHD package to power spectrum
generation in the ppsilon package. In particular, we focus on the
distinguishing characteristics of FHD/ppsilon: highly accurate
spectral calibration, extensive data verification products, and end-to-end
error propagation. We present our key data analysis products in detail to
facilitate understanding of the prominent systematics in image-based power
spectrum analyses. As a verification to our analysis, we also highlight a
full-pipeline analysis simulation to demonstrate signal preservation and lack
of signal loss. This careful treatment ensures that the
FHD/ppsilon power spectrum pipeline can reduce radio
interferometric data to produce credible 21 cm EoR measurements.Comment: 21 pages, 10 figures, accepted by PAS
Observations of tidal variability on the New England shelf
Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C06010, doi:10.1029/2003JC001972.Observations from the Coastal Mixing and Optics experiment moored array, deployed from August 1996 through June 1997, are used to describe barotropic and baroclinic tidal variability over the New England shelf. The dominant M 2 tidal elevations decrease toward the northeast to a minimum over the Nantucket shoals (about 34 cm), and barotropic tidal current amplitudes increase strongly toward the northeast to a maximum over the shoals (about 35 cm sâ1). Estimates of the depth-averaged M 2 momentum balance indicate that tidal dynamics are linear, and along-shelf pressure gradients are as large as cross-shelf pressure gradients. In addition, tidal current ellipses are weakly polarized, confirming that the dynamics are more complex than simple plane waves. The vertical structure of the M 2 currents decreases in amplitude and phase (phase lead near bottom) over the bottom 20 m. The M 2 momentum deficit near the bottom approximately matches direct covariance estimates of stress, confirming the effects of stress on current structure in the tidally driven bottom boundary layer. Baroclinic current variability at tidal frequencies is small (2 cm sâ1 amplitude), with a predominantly mode 1 vertical structure. High-frequency (approaching the buoyancy frequency) internal solitons are observed following the pycnocline. The internal solitons switch from waves of depression to waves of elevation when the depth of maximum stratification is deeper than half the water column depth. Both low-mode baroclinic tidal and high-frequency internal wave energy decrease linearly with bottom depth across the shelf.Funding for the CMO
experiment and subsequent analysis was provided by the Office of Naval
Research under grants N00014-95-1-0339 and N00014-01-1-0140
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