17,840 research outputs found
The Coulomb interaction and the inverse Faddeev-Popov operator in QCD
We give a proof of a local relation between the inverse Faddeev-Popov
operator and the non-Abelian Coulomb interaction between color charges
Effects of Triclopyr on Variable-Leaf Watermilfoil
The objective of the study described here was to determine
the effect on variable-leaf watermilfoil of various combinations
of triclopyr concentrations and exposure times
using dosage rates that controlled Eurasian watermilfoil under
laboratory and field conditions (Netherland and
Getsinger 1992, Getsinger et al. 1997, Petty et al. 1998)
Gas temperature measurements using the dual-line detection Rayleigh scattering technique
A new laser-induced Rayleigh scattering method is presented for the improved temperature diagnostics of gas flows. In the present technique, the two lines of a copper vapor laser are used to obtain the time and space resolved temperature. A single set of optics is used to form the optical probe and to collect the signal simultaneously from both the 510 nm and the 578 nm lines. The dual-line detection allows for the determination and removal of surface-scattered laser light from a Rayleigh signal thereby improving the applicability of Rayleigh scattering to near wall flows with a high degree of glare. An optical system using the dual-line detection technique is built, calibrated and tested in a hot air jet under various levels of background contamination. The results indicate that highly accurate temperature measurements are possible even when the laser-line background intensity, captured by the collecting optics, is five times that of the Rayleigh signal
Herbicide evaluation for the control of wild taro
Wild taro (Colocasia esculenta (L.) Schott), is an exotic, emergent
perennial that has established in many shallow-water
wetlands throughout the southern United States. Although
wild taro is a cultivated crop in many tropical and subtropical
areas of the world, its invasion in riverine and lacustrine wetlands
in the U.S. has resulted in the loss of habitat for native
plant species. Once established, wild taro forms dense, monotypic
stands that reduce the diversity of native vegetation, as
has occurred in Louisiana, Florida, and Texas (Akridge and
Fonteyn 1981, Simberloff et al. 1997). Akridge and Fonteyn
(1981) reported that although wild taro is considered naturalized
in south-central Texas, its present dominance along
the San Marcos River has altered the native vegetational
structure and dynamics of this river system. The
objective of this study was to evaluate the efficacy of four
aquatic herbicides for control of wild taro
Monopoles contra vortices in SU(2) lattice gauge theory?
We show that the scenario of vortex induced confinement of center--projected
SU(2) lattice gauge theory is not necessarily in conflict with the findings in
the positive plaquette model.Comment: 3 pages, LaTeX, comment to be published in Phys. Rev.
Critical fields and fluctuations determined from specific heat and magnetoresistance in the same nanogram SmFeAs(O,F) single crystal
Through a direct comparison of specific heat and magneto-resistance we
critically asses the nature of superconducting fluctuations in the same
nano-gram crystal of SmFeAs(O, F). We show that although the superconducting
fluctuation contribution to conductivity scales well within the 2D-LLL scheme
its predictions contrast the inherently 3D nature of SmFeAs(O, F) in the
vicinity T_{c}. Furthermore the transition seen in specific heat cannot be
satisfactory described either by the LLL or the XY scaling. Additionally we
have validated, through comparing Hc2 values obtained from the entropy
conservation construction (Hab=-19.5 T/K and Hab=-2.9 T/K), the analysis of
fluctuation contribution to conductivity as a reasonable method for estimating
the Hc2 slope
Structure and Dynamics of amorphous Silica Surfaces
We use molecular dynamics computer simulations to study the equilibrium
properties of the surface of amorphous silica. Two types of geometries are
investigated: i) clusters with different diameters (13.5\AA, 19\AA, and
26.5\AA) and ii) a thin film with thickness 29\AA. We find that the shape of
the clusters is independent of temperature and that it becomes more spherical
with increasing size. The surface energy is in qualitative agreement with the
experimental value for the surface tension. The density distribution function
shows a small peak just below the surface, the origin of which is traced back
to a local chemical ordering at the surface. Close to the surface the partial
radial distribution functions as well as the distributions of the bond-bond
angles show features which are not observed in the interior of the systems. By
calculating the distribution of the length of the Si-O rings we can show that
these additional features are related to the presence of two-membered rings at
the surface. The surface density of these structures is around 0.6/nm^2 in good
agreement with experimental estimates. From the behavior of the mean-squared
displacement at low temperatures we conclude that at the surface the cage of
the particles is larger than the one in the bulk. Close to the surface the
diffusion constant is somewhat larger than the one in the bulk and with
decreasing temperature the relative difference grows. The total vibrational
density of states at the surface is similar to the one in the bulk. However, if
only the one for the silicon atoms is considered, significant differences are
found.Comment: 30 pages of Latex, 16 figure
Radio Detection of SN 1986E in NGC 4302
Radio observations of SN 1986E have shown a clear detection of emission at 6
cm wavelength about 8 months after optical discovery. Combined with a number of
new upper limits and a study of the possible models, it appears that SN 1986E
was probably a fairly normal Type IIL supernova, somewhat similar to SN 1980K,
with radio emission at roughly expected levels. This detection continues the
correlation between radio detection and late time optical emission.Comment: 14 pages, LaTeX (AASTeX), 2 PostScript figures, to appear in ApJ
(Letters
- …
