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The ARM Mobile Facility and its first international deployment: measuring radiative flux divergence in West Africa
Reversible gelation and dynamical arrest of dipolar colloids
We use molecular dynamics simulations of a simple model to show that
dispersions of slightly elongated colloidal particles with long-range dipolar
interactions, like ferrofluids, can form a physical (reversible) gel at low
volume fractions. On cooling, the particles first self-assemble into a
transient percolating network of cross-linked chains, which, at much lower
temperatures, then undergoes a kinetic transition to a dynamically arrested
state with broken ergodicity. This transition from a transient to a frozen gel
is characterised by dynamical signatures reminiscent of jamming in much denser
dispersions.Comment: 6 pages, 7 figure
Structural trends in clusters of quadrupolar spheres
The influence of quadrupolar interactions on the structure of small clusters
is investigated by adding a point quadrupole of variable strength to the
Lennard-Jones potential. Competition arises between sheet-like arrangements of
the particles, favoured by the quadrupoles, and compact structures, favoured by
the isotropic Lennard-Jones attraction. Putative global potential energy minima
are obtained for clusters of up to 25 particles using the basin-hopping
algorithm. A number of structural motifs and growth sequences emerge, including
star-like structures, tubes, shells and sheets. The results are discussed in
the context of colloidal self-assembly.Comment: 8 pages, 6 figure
Color Transparency at COMPASS energies
Pionic quasielastic knockout of protons from nuclei at 200 GeV show very
large effects of color transparency as -t increases from 0 to several GeV^2.
Similar effects are expected for quasielastic photoproduction of vector mesons.Comment: 9 pages, 4 figure
Experimental Characterization of Roughness and Flow Injection Effects in a High Reynolds Number Turbulent Channel
A turbulent channel flow was used to study the scaling of the combined effects of roughness and flow injection on the mean flow and turbulence statistics of turbulent plane Poiseuille flow. It was found that the additional momentum injected through the rough surface acted primarily to enhance the roughness effects and, with respect to the mean flow, blowing produced similar mean flow effects as increasing the roughness height. This was not found to hold for the turbulence statistics, as a departure from Townsend’s hypothesis was seen. Instead, the resulting outer-scaled streamwise Reynolds stress for cases with roughness and blowing deviated significantly from the roughness only condition well throughout the inner and outer layers. Investigation into this phenomena indicated that suppression of the large-scale motions due to blowing may have been contributing to this deviation
The Clean Air Act Amendments of 1990 and an Unbridled Spending Power: Will They Survive on the Supreme Court\u27s Road to Substantive Federalism
The question remains as to how far the Supreme Court will go in its refortification of the Tenth Amendment. This Note explores emerging federalism trends and evaluates the CAA in light of a stronger state sovereignty that is appearing on the constitutional horizon. Parts II and III examine the CAAA and the constitutional problems engendered by the Act. Part IV examines current Tenth Amendment and Spending Clause jurisprudence, and illustrates that the CAAA is a classic example of how Congress has been able to circumvent the Tenth Amendment with its Spending power. Part V presents a new view of federalism that is materializing in Commerce Clause and Eleventh Amendment doctrine, and extends that theory to the Tenth Amendment in the hope of finding a substantive bar on Congress\u27s excessive use of the Spending power. Part VI calls for a restructuring of the CAAA to promote its high objectives, and concludes that unless the Act falls in line with the substantive federalism trend, its objectives will not be fulfilled
Structural relaxation in Morse clusters: Energy landscapes
We perform a comprehensive survey of the potential energy landscapes of
13-atom Morse clusters, and describe how they can be characterized and
visualized. Our aim is to detail how the global features of the funnel-like
surface change with the range of the potential, and to relate these changes to
the dynamics of structural relaxation. We find that the landscape becomes
rougher and less steep as the range of the potential decreases, and that
relaxation paths to the global minimum become more complicated.Comment: 21 pages, 3 tables, 5 figure
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