10,734 research outputs found
Space Shuttle: MDAC/MMC space shuttle booster determination of stability and control characteristics and power effects at subsonic speed, Mach numbers zero and 0.26
Low speed wind tunnel tests of stability and control characteristics of space shuttle booster at subsonic speed
UCAC3 Proper Motion Survey. II. Discovery Of New Proper Motion Stars In UCAC3 With 0.40" yr^-1 > mu >= 0.18" yr^-1 Between Declinations -47 deg and 00 deg
We present 474 new proper motion stellar systems in the southern sky having
no previously known components, with 0.40" yr^-1 > mu >= 0.18" yr^-1 between
declinations -47 deg and 00 deg. In this second paper utilizing the U.S. Naval
Observatory third CCD Astrograph Catalog (UCAC3) we complete our sweep of the
southern sky for objects in the proper motion range targeted by this survey
with R magnitudes ranging from 9.80 to 19.61. The new systems contribute a ~16%
increase in the number of new stellar systems for the same region of sky
reported in previous SuperCOSMOS RECONS (SCR) surveys. Among the newly
discovered stellar systems are 16 multiples, plus an additional 10 components
that are new common proper motion companions to previously known objects. A
comparison of UCAC3 proper motions to those from Hipparcos, Tycho-2, Southern
Proper Motion (SPM4), and SuperCOSMOS indicates that all proper motions are
consistent to ~10 mas/yr, with the exception of SuperCOSMOS. Distance estimates
are derived for all stellar systems having SuperCOSMOS Sky Survey (SSS) B_J,
R_59F, and I_IVN plate magnitudes and Two-Micron All Sky Survey (2MASS)
infrared photometry. We find five new red dwarf systems estimated to be within
25 pc. These discoveries support results from previous proper motion surveys
suggesting that more nearby stellar systems are to be found, particularly in
the fainter, slower moving samples.
In this second paper utilizing the U.S. Naval Observatory third CCD
Astrograph Catalog (UCAC3) we complete our sweep of the southern sky for
objects in the proper motion range targeted by this survey with R magnitudes
ranging from 9.80 to 19.61.Comment: 24 pages, 7 figures and 4 tables. Accepted for publication in Ap
Scalar Top Quark Studies with Various Visible Energies
The precision determination of scalar top quark properties will play an
important role at a future International Linear Collider (ILC). Recent and
ongoing studies are discussed for different experimental topologies in the
detector. First results are presented for small mass differences between the
scalar top and neutralino masses. This corresponds to a small expected visible
energy in the detector. An ILC will be a unique accelerator to explore this
scenario. In addition to finding the existence of light stop quarks, the
precise measurement of their properties is crucial for testing their impact on
the dark matter relic abundance and the mechanism of electroweak baryogenesis.
Significant sensitivity for mass differences down to 5 GeV are obtained. The
simulation is based on a fast and realistic detector simulation. A vertex
detector concept of the Linear Collider Flavor Identification
(LCFI)collaboration, which studies pixel detectors for heavy quark flavour
identification, is implemented in the simulations for c-quark tagging. The
study extends simulations for large mass differences (large visible energy) for
which aspects of different detector simulations, the vertex detector design,
and different methods for the determination of the scalar top mass are
discussed. Based on the detailed simulations we study the uncertainties for the
dark matter density predictions and their estimated uncertainties from various
sources. In the region of parameters where stop-neutralino co-annihilation
leads to a value of the relic density consistent with experimental results, as
precisely determined by the Wilkinson Microwave Anisotropy Probe (WMAP), the
stop-neutralino mass difference is small and the ILC will be able to explore
this region efficiently.Comment: 11 pages, 11 figures, presented at SUSY'0
Giant thermopower and figure of merit in single-molecule devices
We present a study of the thermopower and the dimensionless figure of
merit in molecules sandwiched between gold electrodes. We show that for
molecules with side groups, the shape of the transmission coefficient can be
dramatically modified by Fano resonances near the Fermi energy, which can be
tuned to produce huge increases in and . This shows that molecules
exhibiting Fano resonances have a high efficiency of thermoelectric cooling
which is not present for conventional un-gated molecules with only delocalized
states along their backbone.Comment: 4 pages, 4 figure
The Solar Neighborhood XXV: Discovery of New Proper Motion Stars with 0.40 "/yr > mu > 0.18 "/yr between Declinations -47 degrees and 00 degrees
We present 2817 new southern proper motion systems with 0.40 "/yr > mu > 0.18
"/yr and declination between -47 degrees and 00 degrees. This is a continuation
of the SuperCOSMOS-RECONS (SCR) proper motion searches of the southern sky. We
use the same photometric relations as previous searches to provide distance
estimates based on the assumption that the objects are single main sequence
stars. We find 79 new red dwarf systems predicted to be within 25 pc, including
a few new components of previously known systems. Two systems - SCR 1731-2452
at 9.5 pc and SCR 1746-3214 at 9.9 pc - are anticipated to be within 10 pc. We
also find 23 new white dwarf candidates with distance estimates of 15-66 pc, as
well as 360 new red subdwarf candidates. With this search, we complete the SCR
sweep of the southern sky for stars with mu > 0.18 "/yr and R_59F < 16.5,
resulting in a total of 5042 objects in 4724 previously unreported proper
motion systems. Here we provide selected comprehensive lists from our SCR
proper motion search to date, including 152 red dwarf systems estimated to be
within 25 pc (nine within 10 pc), 46 white dwarfs (ten within 25 pc), and 598
subdwarf candidates. The results of this search suggest that there are more
nearby systems to be found at fainter magnitudes and lower proper motion limits
than those probed so far.Comment: 47 pages, 16 of text. 7 figure
Anatomy of a catchment: the relation of physical attributes of the Plynlimon catchments to variations in hydrology and water status
International audienceThe Plynlimon headwater catchments in mid-Wales have been a landmark study of water resources in the UK uplands for over 30 years. The main physical features of the catchments have been digitised as the basis for linking new model developments and process understanding. Examples are given of how the main physical attributes are related to land management, hydrology and water quality. These data are also being used to provide insights into catchment processes that may underpin the development of new research. This work is particularly relevant given the need for the assessment of water status under the Water Framework Directive. The paper presents hypothetical management scenarios for the catchments, to show how ecological status may be improved, for example, by selectively restructuring areas of commercial forest. Keywords: Plynlimon, GIS, catchment study, forestry, hydrology, WF
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