11,061 research outputs found
Rapid Adaptive Programming using Image Data (RAPID)
In many welding applications, programming time has been the biggest obstacle for the widespread acceptance of robots, impeding the advancement of this technology and limiting it to medium or large batch applications. In particular, for repair of worn components where the damage is irregular, reprogramming by skilled personnel is required at added cost and time. This paper outlines a novel offline programming technique which allows robot programming to be automated and completed in a few seconds. This technique is applicable to a wide range of industrial wear applications
Quantum Measurement and the Aharonov-Bohm Effect with Superposed Magnetic Fluxes
We consider the magnetic flux in a quantum mechanical superposition of two
values and find that the Aharonov-Bohm effect interference pattern contains
information about the nature of the superposition, allowing information about
the state of the flux to be extracted without disturbance. The information is
obtained without transfer of energy or momentum and by accumulated nonlocal
interactions of the vector potential with many charged particles
forming the interference pattern, rather than with a single particle. We
suggest an experimental test using already experimentally realized superposed
currents in a superconducting ring and discuss broader implications.Comment: 6 pages, 4 figures; Changes from version 3: corrected typo (not
present in versions 1 and 2) in Eq. 8; Changes from version 2: shortened
abstract; added refs and material in Section IV. The final publication is
available at: http://link.springer.com/article/10.1007/s11128-013-0652-
Branched polymers, complex spins and the freezing transition
We show that by coupling complex three-state systems to branched-polymer like
ensembles we can obtain models with gamma-string different from one half. It is
also possible to study the interpolation between dynamical and crystalline
graphs for these models; we find that only when geometry fluctuations are
completely forbidden is there a crystalline phase.Comment: 14 pages plain LateX2e, 4 eps figures included using eps
Observation of bosonic coalescence of photon pairs
Quantum theory predicts that two indistinguishable photons incident on a
beam-splitter interferometer stick together as they exit the device (the pair
emerges randomly from one port or the other). We use a special
photon-number-resolving energy detector for a direct loophole-free observation
of this quantum-interference phenomenon. Simultaneous measurements from two
such detectors, one at each beam-splitter output port, confirm the absence of
cross-coincidences.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let
Detection of lensing substructure using ALMA observations of the dusty galaxy SDP.81
We study the abundance of substructure in the matter density near galaxies
using ALMA Science Verification observations of the strong lensing system
SDP.81. We present a method to measure the abundance of subhalos around
galaxies using interferometric observations of gravitational lenses. Using
simulated ALMA observations, we explore the effects of various systematics,
including antenna phase errors and source priors, and show how such errors may
be measured or marginalized. We apply our formalism to ALMA observations of
SDP.81. We find evidence for the presence of a
subhalo near one of the images, with a significance of in a joint
fit to data from bands 6 and 7; the effect of the subhalo is also detected in
both bands individually. We also derive constraints on the abundance of dark
matter subhalos down to , pushing down to the
mass regime of the smallest detected satellites in the Local Group, where there
are significant discrepancies between the observed population of luminous
galaxies and predicted dark matter subhalos. We find hints of additional
substructure, warranting further study using the full SDP.81 dataset
(including, for example, the spectroscopic imaging of the lensed carbon
monoxide emission). We compare the results of this search to the predictions of
CDM halos, and find that given current uncertainties in the host halo
properties of SDP.81, our measurements of substructure are consistent with
theoretical expectations. Observations of larger samples of gravitational
lenses with ALMA should be able to improve the constraints on the abundance of
galactic substructure.Comment: 18 pages, 13 figures, Comments are welcom
Biochemomechanics of intraluminal thrombus in abdominal aortic aneurysms
Most computational models of abdominal aortic aneurysms address either the hemodynamics within the lesion or the mechanics of the wall. More recently, however, some models have appropriately begun to account for the evolving mechanics of the wall in response to the changing hemodynamic loads. Collectively, this large body of work has provided tremendous insight into this life-threatening condition and has provided important guidance for current research. Nevertheless, there has yet to be a comprehensive model that addresses the mechanobiology, biochemistry, and biomechanics of thrombus-laden abdominal aortic aneurysms. That is, there is a pressing need to include effects of the hemodynamics on both the development of the nearly ubiquitous intraluminal thrombus and the evolving mechanics of the wall, which depends in part on biochemical effects of the adjacent thrombus. Indeed, there is increasing evidence that intraluminal thrombus in abdominal aortic aneurysms is biologically active and should not be treated as homogeneous inert material. In this review paper, we bring together diverse findings from the literature to encourage next generation models that account for the biochemomechanics of growth and remodeling in patient-specific, thrombus-laden abdominal aortic aneurysms
Joint searches between gravitational-wave interferometers and high-energy neutrino telescopes: science reach and analysis strategies
Many of the astrophysical sources and violent phenomena observed in our
Universe are potential emitters of gravitational waves (GWs) and high-energy
neutrinos (HENs). A network of GW detectors such as LIGO and Virgo can
determine the direction/time of GW bursts while the IceCube and ANTARES
neutrino telescopes can also provide accurate directional information for HEN
events. Requiring the consistency between both, totally independent, detection
channels shall enable new searches for cosmic events arriving from potential
common sources, of which many extra-galactic objects.Comment: 4 pages. To appear in the Proceedings of the 2d Heidelberg Workshop:
"High-Energy Gamma-rays and Neutrinos from Extra-Galactic Sources",
Heidelberg (Germany), January 13-16, 200
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