185 research outputs found
Load distribution during sit-stand-sit using an instrumented chair
Paper examining the forces through the body during standing up and sitting down by means of force plates and transducers
Feltability of cashmere and other rare animal fibres and the effects of nutrition and blending with wool on cashmere feltability
Felting is a unique attribute of animal fibres used for the production of a range of industrial and apparel textiles. Felting can be an adverse attribute as a consequence of dimensional shrinkage during laundering. As there is little objective information regarding the feltability of rare animal fibres or the factors which may affect felting three investigations were undertaken. A survey (n = 114) of the feltability of cashmere from different origins of production, cashgora, quivet, camel hair, llama, guanaco, bison wool, cow fibre and yak wool quantified the large variation between and within these fibre types. Cashmere from some origins and cashgora produced higher feltball density than the other fibres. Different nutritional management of cashmere goats (n = 35) showed that cashmere grown by poorly fed goats had a lower propensity to felt compared with cashmere grown by better fed goats. A consequence of the progressive blending of cashmere (n = 27) with a low propensity to felt superfine wool (high fibre curvature) increased the propensity of the blend to felt, but when the same cashmere was blended with low curvature superfine wool, there was little or no effect on feltability. The mechanisms which lead to variance in feltability of these fibres were quantified with multiple regression modelling. The mechanisms were similar to those reported for wools, namely variations in the resistance to compression, fibre curvature and mean fibre diameter, with likely effects of fibre crimp form. It is possible to source cashmere and other animal fibres which have different propensities to felt and therefore to produce textiles which are likely to have different textile properties.<br /
Molecular accretion in the core of the galaxy cluster 2A 0335+096
We present adaptive optics-assisted K-band integral field spectroscopy of the central cluster galaxy in 2A 0335+096 (z= 0.0349). The H2 v=1â0 S(1) emission is concentrated in two peaks within 600 pc of the nucleus and fainter but kinematically active emission extends towards the nucleus. The H2 is in a rotating structure which aligns with, and appears to have been accreted from, a stream of Hα emission extending over 14 kpc towards a companion galaxy. The projected rotation axis aligns with the 5 GHz radio lobes. This H2 traces the known 1.2 Ă 109 Mâ CO-emitting reservoir; limits on the BrÎł emission confirm that the H2 emission is not excited by star formation, which occurs at a rate of less than 1 Mâ yrâ1 in this gas. If its accretion on to the black hole can be regulated whilst star formation remains suppressed, the reservoir could last for at least 1 Gyr; the simultaneous accretion of just âŒ5 per cent of the gas could drive a series of active galactic nucleus (AGN) outbursts which offset X-ray cooling in the cluster core for the full âŒ1 Gyr. Alternatively, if the regulation is ineffective and the bulk of the H2 accretes within a few orbital periods (25â100 Myr), the resulting 1062 erg outburst would be among the most powerful cluster AGN outbursts known. In either case, these observations further support cold feedback scenarios for AGN heating
Gemini Observations of Disks and Jets in Young Stellar Objects and in Active Galaxies
We present first results from the Near-infrared Integral Field Spectrograph
(NIFS) located at Gemini North. For the active galaxies Cygnus A and Perseus A
we observe rotationally-supported accretion disks and adduce the existence of
massive central black holes and estimate their masses. In Cygnus A we also see
remarkable high-excitation ionization cones dominated by photoionization from
the central engine. In the T-Tauri stars HV Tau C and DG Tau we see
highly-collimated bipolar outflows in the [Fe II] 1.644 micron line, surrounded
by a slower molecular bipolar outflow seen in the H_2 lines, in accordance with
the model advocated by Pyo et al. (2002).Comment: Invited paper presented at the 5th Stromlo Symposium. 9 pages, 7
figures. Accepted for publication in Astrophysics & Space Scienc
A comparative study on the felting propensity of animal fibers
The felting propensity of different animal fibers, particularly alpaca and wool, has been examined. The Aachen felting test method was employed. 1 g of each type of fiber was soaked in 50 ml of wetting solution and agitated in a dyeing machine to make felt balls. The diameter of each ball was measured in nine directions and the ball density was calculated in g/cm3; the higher the density value of the ball, the higher the feltability of the fibers. The effects of fiber diameter and fiber length on the felting propensity of these fibers were investigated. The results show that the alpaca fibers felt to a higher degree than wool fibers, and short and fine cashmere fibers have lower felting propensity than wool fibers at a similar diameter range. There is a higher tendency of felting for bleached and dyed alpaca fibers than for untreated fibers. Fiber length has a remarkable influence on the propensity of fiber felting. Cotton and nylon fibers were also tested for felting propensity to verify the mechanism responsible for the different fiber felting behavior. <br /
Origins of the Ambient Solar Wind: Implications for Space Weather
The Sun's outer atmosphere is heated to temperatures of millions of degrees,
and solar plasma flows out into interplanetary space at supersonic speeds. This
paper reviews our current understanding of these interrelated problems: coronal
heating and the acceleration of the ambient solar wind. We also discuss where
the community stands in its ability to forecast how variations in the solar
wind (i.e., fast and slow wind streams) impact the Earth. Although the last few
decades have seen significant progress in observations and modeling, we still
do not have a complete understanding of the relevant physical processes, nor do
we have a quantitatively precise census of which coronal structures contribute
to specific types of solar wind. Fast streams are known to be connected to the
central regions of large coronal holes. Slow streams, however, appear to come
from a wide range of sources, including streamers, pseudostreamers, coronal
loops, active regions, and coronal hole boundaries. Complicating our
understanding even more is the fact that processes such as turbulence,
stream-stream interactions, and Coulomb collisions can make it difficult to
unambiguously map a parcel measured at 1 AU back down to its coronal source. We
also review recent progress -- in theoretical modeling, observational data
analysis, and forecasting techniques that sit at the interface between data and
theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue
connected with a 2016 ISSI workshop on "The Scientific Foundations of Space
Weather." 44 pages, 9 figure
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
First observation of the decay and a measurement of the ratio of branching fractions
The first observation of the decay using
data collected by the LHCb detector at a centre-of-mass energy of 7 TeV,
corresponding to an integrated luminosity of 36 pb, is reported. A
signal of events is obtained and the absence of signal is
rejected with a statistical significance of more than nine standard deviations.
The branching fraction is measured relative to
that of : , where the first uncertainty is statistical, the second systematic and
the third is due to the uncertainty on the ratio of the and
hadronisation fractions.Comment: 10 pages, 3 figures, submitted to Phys. Lett. B; ISSN 0370-269
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
Absolute luminosity measurements with the LHCb detector at the LHC
Absolute luminosity measurements are of general interest for colliding-beam
experiments at storage rings. These measurements are necessary to determine the
absolute cross-sections of reaction processes and are valuable to quantify the
performance of the accelerator. Using data taken in 2010, LHCb has applied two
methods to determine the absolute scale of its luminosity measurements for
proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In
addition to the classic "van der Meer scan" method a novel technique has been
developed which makes use of direct imaging of the individual beams using
beam-gas and beam-beam interactions. This beam imaging method is made possible
by the high resolution of the LHCb vertex detector and the close proximity of
the detector to the beams, and allows beam parameters such as positions, angles
and widths to be determined. The results of the two methods have comparable
precision and are in good agreement. Combining the two methods, an overall
precision of 3.5% in the absolute luminosity determination is reached. The
techniques used to transport the absolute luminosity calibration to the full
2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6,
9 and 10 and corresponding explanation in the tex
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