284 research outputs found
New Hampshire Motor Transport Association v. Rowe: Federal Preemption of Maine\u27s Attempt to Regulate Internet Sales of Tobacco to Minors
In New Hampshire Motor Transport Ass\u27n v. Rowe, trade associations sought a declaratory judgment that the Federal Aviation Administration Authorization Act of 1994 (FAAAA) preempts a Maine law enacted to facilitate collection of state taxes and restrict the delivery of tobacco products to minors (the Tobacco Delivery Law). The district court granted the plaintiffs\u27 second motion for summary judgment in part, finding that a single provision of little independent consequence escaped preemption, and enjoined enforcement of the preempted provisions. The state appealed to the United States Court of Appeals for the First Circuit, which held that most of Maine\u27s Tobacco Delivery Law is preempted. Maine argued that its efforts to protect the health and welfare of its minor citizens and collect unpaid tobacco taxes cannot be characterized as components of an artificial regulatory structure. To the contrary, the state maintained that its law (1) is foremost a legitimate exercise of Maine\u27s police power that advances a vested interest of the state as a consumer of federal grants and a provider of health-related anti-smoking services for minors, and (2) was duly enacted pursuant to its concurrent jurisdiction-as provided by federal law-to enforce proscriptions on trafficking in contraband cigarettes. Is it possible that Maine over-reached by combining in a single enactment a revenue collection provision and a citizen health provision? Should simpler mechanisms be employed to forestall a future adverse preemption ruling based on a finding of “forbidden significant effect” of state law on interstate carriers? Does New York\u27s law-which proscribes all delivery of cigarettes to consumers-represent a viable model? Congress should clarify the inherent authority of the states to control the importation of harmful tobacco products across their borders. Only by affirming the jurisdiction of states in the quasi-regulation of instrumentalities of interstate commerce-when those instrumentalities choose to deal in notoriously harmful consumer goods-can the seemingly intractable issues raised by the N.H. Motor Transport litigation be put to rest
Complexing additives to reduce the immiscible phase formed in the hybrid ZnBr2 flow battery
The zinc-bromine redox flow battery (RFB) is one of a very few commercially viable RFB energy storage system capable of integration with intermittent renewable energy sources to deliver improved energy management. However, due to the volatility of the electrogenerated bromine and potential for its crossover from positive to negative electrolytes, this system requires the use of quaternary ammonium complexes (N-methyl-N-ethylpyrrolidinium, (MEP)) to capture this bromine. This produces an immiscible phase with the Br2 which requires a complex network of pipes, pumps and automated controls to ensure access to the electroactive material during discharge. In this work, the use of novel quaternary ammonium complexes to capture the electrogenerated bromine but to keep it in the aqueous phase is examined. Three compounds, 1-(carboxymethyl) pyridine-1-ium, 1-(2-carboxymethyl)-1-methylmorpholin-1-ium and 1-(2-carboxymethyl)-1-methylpyrrolidin-1-ium, were found to successfully reduce the volume of the immiscible phase formed on complexing with the polybromide (Brx-) whilst displaying similar enthalpy of vaporisation values as that of MEP. Electrochemical analysis also revealed that these compounds did not impact on the electrode kinetics of the Br-/Brx- reaction indicating that the resulting surface film formed with these compounds behaved as a chemically modified electrode, in contrast to the surface film formed with MEP
Common Representation of Information Flows for Dynamic Coalitions
We propose a formal foundation for reasoning about access control policies
within a Dynamic Coalition, defining an abstraction over existing access
control models and providing mechanisms for translation of those models into
information-flow domain. The abstracted information-flow domain model, called a
Common Representation, can then be used for defining a way to control the
evolution of Dynamic Coalitions with respect to information flow
The Extreme-ultraviolet Emission from Sun-grazing Comets
The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory has observed two Sun-grazing comets as they passed through the solar atmosphere. Both passages resulted in a measurable enhancement of extreme-ultraviolet (EUV) radiance in several of the AIA bandpasses.We explain this EUV emission by considering the evolution of the cometary atmosphere as it interacts with the ambient solar atmosphere. Molecules in the comet rapidly sublimate as it approaches the Sun. They are then photodissociated by the solar radiation field to create atomic species. Subsequent ionization of these atoms produces a higher abundance of ions than normally present in the corona and results in EUV emission in the wavelength ranges of the AIA telescope passbands
A new approach to analyzing solar coronal spectra and updated collisional ionization equilibrium calculations. II. Additional ionization rate coefficients
We have reanalyzed SUMER observations of a parcel of coronal gas using new
collisional ionization equilibrium (CIE) calculations. These improved CIE
fractional abundances were calculated using state-of-the-art electron-ion
recombination data for K-shell, L-shell, Na-like, and Mg-like ions of all
elements from H through Zn and, additionally, Al- through Ar-like ions of Fe.
They also incorporate the latest recommended electron impact ionization data
for all ions of H through Zn. Improved CIE calculations based on these
recombination and ionization data are presented here. We have also developed a
new systematic method for determining the average emission measure () and
electron temperature () of an isothermal plasma. With our new CIE data and
our new approach for determining average and , we have reanalyzed
SUMER observations of the solar corona. We have compared our results with those
of previous studies and found some significant differences for the derived
and . We have also calculated the enhancement of coronal elemental
abundances compared to their photospheric abundances, using the SUMER
observations themselves to determine the abundance enhancement factor for each
of the emitting elements. Our observationally derived first ionization
potential (FIP) factors are in reasonable agreement with the theoretical model
of Laming (2008).Comment: 147 pages (102 of which are online only tables and figures).
Submitted to ApJ. Version 2 is updated addressing the referee's repor
Verification in Staged Tile Self-Assembly
We prove the unique assembly and unique shape verification problems,
benchmark measures of self-assembly model power, are
-hard and contained in (and in
for staged systems with stages). En route,
we prove that unique shape verification problem in the 2HAM is
-complete.Comment: An abstract version will appear in the proceedings of UCNC 201
Optimal spectral lines for measuring chromospheric magnetic fields
This paper identifies spectral lines from X-ray to infrared wavelengths which
are optimally suited to measuring vector magnetic fields as high as possible in
the solar atmosphere. Instrumental and Earth's atmospheric properties, as well
as solar abundances, atmospheric properties and elementary atomic physics are
considered without bias towards particular wavelengths or diagnostic
techniques. While narrowly-focused investigations of individual lines have been
reported in detail, no assessment of the comparative merits of all lines has
ever been published. Although in the UV, on balance the Mg+ h and k lines near
2800 Angstroms are optimally suited to polarimetry of plasma near the base of
the solar corona. This result was unanticipated, given that longer-wavelength
lines offer greater sensitivity to the Zeeman effect. While these lines sample
optical depths photosphere to the coronal base, we argue that cores of multiple
spectral lines provide a far more discriminating probe of magnetic structure as
a function of optical depth than the core and inner wings of a strong line.
Thus, together with many chromospheric lines of Fe+ between 2585 and the h line
at 2803 Angstrom, this UV region promises new discoveries concerning how the
magnetic fields emerge, heat, and accelerate plasma as they battle to dominate
the force and energy balance within the poorly-understood chromosphere.Comment: Accepted for publication in the Astrophysical Journal. 12 pages, 2
figures, and 1 tabl
Dielectronic Recombination of Argon-Like Ions
We present a theoretical investigation of dielectronic recombination (DR) of
Ar-like ions that sheds new light on the behavior of the rate coefficient at
low-temperatures where these ions form in photoionized plasmas. We provide
results for the total and partial Maxwellian-averaged DR rate coefficients from
the initial ground level of K II -- Zn XIII ions. It is expected that these new
results will advance the accuracy of the ionization balance for Ar-like M-shell
ions and pave the way towards a detailed modeling of astrophysically relevant
X-ray absorption features. We utilize the AUTOSTRUCTURE computer code to obtain
the accurate core-excitation thresholds in target ions and carry out
multiconfiguration Breit-Pauli (MCBP) calculations of the DR cross section in
the independent-processes, isolated-resonance, distorted-wave (IPIRDW)
approximation. Our results mediate the complete absence of direct DR
calculations for certain Ar-like ions and question the reliability of the
existing empirical rate formulas, often inferred from renormalized data within
this isoelectronic sequence
A solar spectroscopic absolute abundance of argon from RESIK
Observations of He-like and H-like Ar (Ar XVII and Ar XVIII) lines at 3.949
Angstroms and 3.733 Angstroms respectively with the RESIK X-ray spectrometer on
the CORONAS-F spacecraft, together with temperatures and emission measures from
the two channels of GOES, have been analyzed to obtain the abundance of Ar in
flare plasmas in the solar corona. The line fluxes per unit emission measure
show a temperature dependence like that predicted from theory, and lead to
spectroscopically determined values for the absolute Ar abundance, A(Ar) = 6.44
pm 0.07 (Ar XVII) and 6.49 pm 0.16 (Ar XVIII) which are in agreement to within
uncertainties. The weighted mean is 6.45 pm 0.06, which is between two recent
compilations of the solar Ar abundance and suggest that the photospheric and
coronal abundances of Ar are very similar.Comment: 4 figure
The Power of Duples (in Self-Assembly): It's Not So Hip To Be Square
In this paper we define the Dupled abstract Tile Assembly Model (DaTAM),
which is a slight extension to the abstract Tile Assembly Model (aTAM) that
allows for not only the standard square tiles, but also "duple" tiles which are
rectangles pre-formed by the joining of two square tiles. We show that the
addition of duples allows for powerful behaviors of self-assembling systems at
temperature 1, meaning systems which exclude the requirement of cooperative
binding by tiles (i.e., the requirement that a tile must be able to bind to at
least 2 tiles in an existing assembly if it is to attach). Cooperative binding
is conjectured to be required in the standard aTAM for Turing universal
computation and the efficient self-assembly of shapes, but we show that in the
DaTAM these behaviors can in fact be exhibited at temperature 1. We then show
that the DaTAM doesn't provide asymptotic improvements over the aTAM in its
ability to efficiently build thin rectangles. Finally, we present a series of
results which prove that the temperature-2 aTAM and temperature-1 DaTAM have
mutually exclusive powers. That is, each is able to self-assemble shapes that
the other can't, and each has systems which cannot be simulated by the other.
Beyond being of purely theoretical interest, these results have practical
motivation as duples have already proven to be useful in laboratory
implementations of DNA-based tiles
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