38,123 research outputs found
Double transverse spin asymmetry in the Drell-Yan process from Sivers functions
We show that the transverse double spin asymmetry (DSA) in the Drell-Yan
process contributed only from the Sivers functions can be picked out by the
weighting function
.
The asymmetry is proportional to the product of two Sivers functions from each
hadron . Using two sets of Sivers
functions extracted from the semi-inclusive deeply elastic scattering data at
HERMES, we estimate this asymmetry in the
Drell-Yan process which is possible to be performed in HESR at GSI. The
prediction of DSA in the Drell-Yan process contributed by the function
g_{1T}(x,\Vec k_T^2), which can be extracted by the weighting function
,
is also given at GSI.Comment: 6 latex pages, 2 figures, to appear in PR
Reusable Augmented Concrete System: Accessible Method for Formwork Manufacturing through Holographic Guidance
Reinforced concrete has been one of the essential materials for modern architecture for the last hundred years. Its use is entirely global, having been adopted by all cultures and styles since its invention in the late 19th century. Although its value is excellent due to its low cost, durability and adaptability, its environmental impact is significant, being, in fact, one of the most polluting industries in the world (Babor et al. 2009). This experimental project will research a more sustainable use of concrete, exploring a new form of reusable concrete formwork that will ideally reduce the CO2 footprint by removing wood waste in the casting process and replacing it with adaptable metal components. The modular part-based system for the concrete casting also attempts to simplify one of the current complexities for concrete construction, the Skilled-Labour shortage. (Yusoff et al. 2021). To mitigate this problem, the project also proposes using an Augmented Assembly logic for the casting parts to guide the ensemble and dismantle the formwork through an optimised algorithmic logic. The use of Augmented Reality as a replacement for traditional paper instructions will facilitate access to more workers to this construction art and potentially improve access to optimised use of concrete in developing communities with restricted building technological resources
The Influence of Maleation on Polymer Adsorption and Fixation, Wood Surface Wettability, and Interfacial Bonding Strength in Wood-PVC Composites1
The influence of maleation on polymer adsorption and fixation, surface wettability of maleated wood specimens, and interfacial bonding strength of wood-PVC composites was investigated in this study. Two maleated polypropylenes (MAPPs), Epolene E-43 and Epolene G-3015, were used to treat yellow-poplar veneer samples. Retention of coupling agent, graft rate, graft efficiency, static contact angle on treated samples, and shear strength of resultant wood-PVC laminates manufactured under hot-pressing were measured. It was shown that the relationship among graft rate, coupling agent retention, and treating solution concentration for MAPP-treated wood specimens followed a three-dimensional paraboloid model. Graft efficiency decreased with the increase of concentration and retention. The relationship between retention and concentration was linear for G-3015 and polynomial for E-43. Maleation treatment greatly improved the compatibility and interfacial adhesion. The veneer samples treated with these two MAPPs presented different wetting behaviors. For G-3015-treated samples, measured contact angles varied from 115Β° to 130Β° independent of retention, graft rate, and wetting time. For E-43-treated samples, retention, graft rate, and wetting time had a significant influence on the contact angle. Compared with controls made of untreated wood and PVC, shear strength of the maleated wood-PVC laminates increased over 20% on average. There was no direct correlation between measured contact angle and shear strength. Extractives had negative effects on retention. However, they did not significantly influence contact angles and interfacial bonding strength. Monolayer models were proposed to illustrate the bonding structure at the interface
Distinct Fermi-Momentum Dependent Energy Gaps in Deeply Underdoped Bi2212
We use angle-resolved photoemission spectroscopy applied to deeply underdoped
cuprate superconductors Bi2Sr2(Ca,Y)Cu2O8 (Bi2212) to reveal the presence of
two distinct energy gaps exhibiting different doping dependence. One gap,
associated with the antinodal region where no coherent peak is observed,
increases with underdoping - a behavior known for more than a decade and
considered as the general gap behavior in the underdoped regime. The other gap,
associated with the near nodal regime where a coherent peak in the spectrum can
be observed, does not increase with less doping - a behavior not observed in
the single particle spectra before. We propose a two-gap scenario in momentum
space that is consistent with other experiments and may contain important
information on the mechanism of high-Tc superconductivity.Comment: 12 pages, 3 figures, submitted to Scienc
The Quintuplet Cluster: Extended Structure and Tidal Radius
The Quintuplet star cluster is one of only three known young ( Myr)
massive (M M) clusters within pc of the Galactic
Center. In order to explore star cluster formation and evolution in this
extreme environment, we analyze the Quintuplet's dynamical structure. Using the
HST WFC3-IR instrument, we take astrometric and photometric observations of the
Quintuplet covering a field-of-view, which is times
larger than those of previous proper motion studies of the Quintuplet. We
generate a catalog of the Quintuplet region with multi-band, near-infrared
photometry, proper motions, and cluster membership probabilities for
stars. We present the radial density profile of candidate Quintuplet
cluster members with M out to pc from the cluster
center. A lower limit of pc is placed on the tidal radius,
indicating the lack of a tidal truncation within this radius range. Only weak
evidence for mass segregation is found, in contrast to the strong mass
segregation found in the Arches cluster, a second and slightly younger massive
cluster near the Galactic Center. It is possible that tidal stripping hampers a
mass segregation signature, though we find no evidence of spatial asymmetry.
Assuming that the Arches and Quintuplet formed with comparable extent, our
measurement of the Quintuplet's comparatively large core radius of
pc provides strong empirical evidence that young massive
clusters in the Galactic Center dissolve on a several Myr timescale.Comment: 25 pages (21-page main text, 4-page appendix), 18 figures, submitted
to Ap
Global gyrokinetic simulations of intrinsic rotation in ASDEX Upgrade Ohmic L-mode plasmas
Non-linear, radially global, turbulence simulations of ASDEX Upgrade (AUG)
plasmas are performed and the nonlinear generated intrinsic flow shows
agreement with the intrinsic flow gradients measured in the core of Ohmic
L-mode plasmas at nominal parameters. Simulations utilising the kinetic
electron model show hollow intrinsic flow profiles as seen in a predominant
number of experiments performed at similar plasma parameters. In addition,
significantly larger flow gradients are seen than in a previous flux-tube
analysis (Hornsby et al {\it Nucl. Fusion} (2017)). Adiabatic electron model
simulations can show a flow profile with opposing sign in the gradient with
respect to a kinetic electron simulation, implying a reversal in the sign of
the residual stress due to kinetic electrons. The shaping of the intrinsic flow
is strongly determined by the density gradient profile. The sensitivity of the
residual stress to variations in density profile curvature is calculated and
seen to be significantly stronger than to neoclassical flows (Hornsby et al
{\it Nucl. Fusion} (2017)). This variation is strong enough on its own to
explain the large variations in the intrinsic flow gradients seen in some AUG
experiments. Analysis of the symmetry breaking properties of the turbulence
shows that profile shearing is the dominant mechanism in producing a finite
parallel wave-number, with turbulence gradient effects contributing a smaller
portion of the parallel wave-vector
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