2,652 research outputs found
Carbon Doping of MgB2 by Toluene and Malic-Acid-in-Toluene
The decomposition of malic acid in the presence of Mg and B was studied using
Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA)
which revealed that malic acid reacted with Mg but not B. Also, the addition of
toluene to dissolve malic acid followed by subsequent drying resulted in no
reaction with Mg, indicating that the malic acid had decomposed during the
dissolution/drying stage. The total carbon contributed by toluene versus a
toluene/5 wt% malic acid mixture was measured using a LECO CS600 carbon
analyzer. The toluene sample contained ~0.4 wt% C while the toluene/malic acid
mixture had ~1.5 wt% C, demonstrating that the toluene contributed a
significant amount of carbon to the final product. Resistivity measurements on
powder-in-tube MgB2 monofilamentary wires established that the toluene/malic
acid doped sample had the highest Bc2. However, the toluene-only sample had the
highest transport Jc over most of the magnetic field range (0-9 T), equaled
only by that of toluene/malic acid sample in fields above 9 T.Comment: 17 pages, 6 figures, 1 tabl
A study of the migratory activity of oreochromis SP erythrocyres and leukocytes
The purpose of our study study of the migratory activity of Oreochromis sp. leukocytes
and erythrocytes under the action of temperature facto
Aligning archive maps and extracting footprints for analysis of historic urban environments.
Archive cartography and archaeologist's sketches are invaluable resources when analysing a historic town or city. A virtual reconstruction of a city provides the user with the ability to navigate and explore an environment which no longer exists to obtain better insight into its design and purpose. However, the process of reconstructing the city from maps depicting features such as building footprints and roads can be labour intensive. In this paper we present techniques to aid in the semi-automatic extraction of building footprints from digital images of archive maps and sketches. Archive maps often exhibit problems in the form of inaccuracies and inconsistencies in scale which can lead to incorrect reconstructions. By aligning archive maps to accurate modern vector data one may reduce these problems. Furthermore, the efficiency of the footprint extraction methods may be improved by aligning either modern vector data or previously extracted footprints, since common elements can be identified between maps of differing time periods and only the difference between the two needs to be extracted. An evaluation of two alignment approaches is presented: using a linear affine transformation and a set of piecewise linear affine transformations
The Constraint of a General Effective Potential in Vector Torsion Coupled Conformally Induced Gravity
It is found that the deviation of an effective potential from the quartic
form is related to the metric and vector torsion dependencies of the effective
potential in the vector torsion coupled conformally induced gravity.Comment: 3pages Revtex 3.0, no figur
Low Mach number effect in simulation of high Mach number flow
In this note, we relate the two well-known difficulties of Godunov schemes:
the carbuncle phenomena in simulating high Mach number flow, and the inaccurate
pressure profile in simulating low Mach number flow. We introduced two simple
low-Mach-number modifications for the classical Roe flux to decrease the
difference between the acoustic and advection contributions of the numerical
dissipation. While the first modification increases the local numerical
dissipation, the second decreases it. The numerical tests on the double-Mach
reflection problem show that both modifications eliminate the kinked Mach stem
suffered by the original flux. These results suggest that, other than
insufficient numerical dissipation near the shock front, the carbuncle
phenomena is strongly relevant to the non-comparable acoustic and advection
contributions of the numerical dissipation produced by Godunov schemes due to
the low Mach number effect.Comment: 9 pages, 1 figur
Interface, Volume, and Thermal Attenuation of Hot-Electron Spins in Ni<sub>80</sub>Fe<sub>20</sub> and Co
The relative importance of interface, volume, and thermal scattering in spin-dependent hot-electron transmission of magnetic trilayers is quantified. While interfaces produce significant attenuation (factor 2.2 per interface), the spin asymmetry is dominated by volume scattering. Extracted thermal attenuation lengths (130 Å at 300 K for Ni.......Fe...) show that thermal spin-wave scattering is stronger than hith-erto assumed. This suggests that spontaneous spin-wave emission, rather than the details of the spin-dependent band structure, may cause the strong filtering of minority hot-electron spins
FastJet user manual
FastJet is a C++ package that provides a broad range of jet finding and
analysis tools. It includes efficient native implementations of all widely used
2-to-1 sequential recombination jet algorithms for pp and e+e- collisions, as
well as access to 3rd party jet algorithms through a plugin mechanism,
including all currently used cone algorithms. FastJet also provides means to
facilitate the manipulation of jet substructure, including some common boosted
heavy-object taggers, as well as tools for estimation of pileup and
underlying-event noise levels, determination of jet areas and subtraction or
suppression of noise in jets.Comment: 69 pages. FastJet 3 is available from http://fastjet.fr
PP-wave Black holes and The Matrix Model
We discuss the sizes of a black hole in the M theory pp-wave background, and
how the transverse size can be reproduced in the matrix model.Comment: 12 pages, harvmac. v2: final version to be published in JHEP, refs.
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