9,894 research outputs found
Scientific Excellence in the Forensic Science Community
This Article was prepared as a companion to the Fordham Law Review Reed Symposium on Forensic Expert Testimony, Daubert, and Rule 702, held on October 27, 2017, at Boston College School of Law. The Symposium took place under the sponsorship of the Judicial Conference Advisory Committee on Evidence Rules. For an overview of the Symposium, see Daniel J. Capra, Foreword: Symposium on Forensic Testimony, Daubert, and Rule 702, 86 Fordham L. Rev. 1459 (2018)
Falling liquid films with blowing and suction
Flow of a thin viscous film down a flat inclined plane becomes unstable to
long wave interfacial fluctuations when the Reynolds number based on the mean
film thickness becomes larger than a critical value (this value decreases as
the angle of inclination with the horizontal increases, and in particular
becomes zero when the plate is vertical). Control of these interfacial
instabilities is relevant to a wide range of industrial applications including
coating processes and heat or mass transfer systems. This study considers the
effect of blowing and suction through the substrate in order to construct from
first principles physically realistic models that can be used for detailed
passive and active control studies of direct relevance to possible experiments.
Two different long-wave, thin-film equations are derived to describe this
system; these include the imposed blowing/suction as well as inertia, surface
tension, gravity and viscosity. The case of spatially periodic blowing and
suction is considered in detail and the bifurcation structure of forced steady
states is explored numerically to predict that steady states cease to exist for
sufficiently large suction speeds since the film locally thins to zero
thickness giving way to dry patches on the substrate. The linear stability of
the resulting nonuniform steady states is investigated for perturbations of
arbitrary wavelengths, and any instabilities are followed into the fully
nonlinear regime using time-dependent computations. The case of small amplitude
blowing/suction is studied analytically both for steady states and their
stability. Finally, the transition between travelling waves and non-uniform
steady states is explored as the suction amplitude increases
Acceleration by pulsar winds in binary systems
In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation and the spin-down power will drive a wind of relativistic electron-positron pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. The authors investigate the possibility of particle acceleration at such a pulsar wind shock and the production of very high energy (VHE) and ultra high energy (UHE) gamma rays from interactions of accelerated protons in the companion star's wind or atmosphere. They find that in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma rays. The authors discuss the application of the pulsar wind model to binary sources such as Cygnus X-3, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems
Multi-strange baryon measurements at LHC energies, with the ALICE experiment
The status of the charged multi-strange baryon analysis (Xi-, anti-Xi+,
Omega-, anti-Omega+) at LHC energies is presented. This report is based on the
results obtained with ALICE (A Large Ion Collider Experiment), profiting from
the characteristic cascade-decay topology. A special attention is drawn to the
early pp data-taking period (2009-2010) and subsequently, on the uncorrected
pT-spectra extracted at mid-rapidity for centre of mass energies of 0.9 TeV and
7 TeV.Comment: 4 pages, 5 figures, Hot Quarks 2010 proceedings, La Londe Les Maures,
France, June 2010 (to be published in Journal of Physics: Conference Series
Entanglement Scrambling in 2d Conformal Field Theory
We investigate how entanglement spreads in time-dependent states of a 1+1
dimensional conformal field theory (CFT). The results depend qualitatively on
the value of the central charge. In rational CFTs, which have central charge
below a critical value, entanglement entropy behaves as if correlations were
carried by free quasiparticles. This leads to long-term memory effects, such as
spikes in the mutual information of widely separated regions at late times.
When the central charge is above the critical value, the quasiparticle picture
fails. Assuming no extended symmetry algebra, any theory with has
diminished memory effects compared to the rational models. In holographic CFTs,
with , these memory effects are eliminated altogether at strong
coupling, but reappear after the scrambling time at
weak coupling.Comment: 52 pages, 7 figure; v2: references adde
Measurement of heavy-flavor production in Pb-Pb collisions at the LHC with ALICE
A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC)
has been built in order to study the Quark-Gluon Plasma (QGP) created in
high-energy nuclear collisions. As heavy-flavor quarks are produced at the
early stage of the collision, they serve as sensitive probes for the QGP. The
ALICE detector with its capabilities such as particle identification, secondary
vertexing and tracking in a high multiplicity environment can address, among
other measurements, the heavy-flavor sector in heavy-ion collisions. We present
latest results on the measurement of the nuclear modification factor of open
heavy-flavors as well as on the measurement of open heavy-flavor azimuthal
anisotropy v2 in Pb-Pb collisions at sqrt(s) = 2.76 TeV. Open charmed hadrons
are reconstructed in the hadronic decay channels D0->Kpi, D+->Kpipi, and
D*+->D0pi applying a secondary decay-vertex topology. Complementary
measurements are performed by detecting electrons (muons) from semi-leptonic
decays of open heavy-flavor hadrons in the central (forward) rapidity region.Comment: 10 pages, 6 figures. Talk given by Robert Grajcarek at the 11th
International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio,
Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in
Journal of Physics: Conference Series (JPCS
Automatic force balance calibration system
A system for automatically calibrating force balances is provided. The invention uses a reference balance aligned with the balance being calibrated to provide superior accuracy while minimizing the time required to complete the calibration. The reference balance and the test balance are rigidly attached together with closely aligned moment centers. Loads placed on the system equally effect each balance, and the differences in the readings of the two balances can be used to generate the calibration matrix for the test balance. Since the accuracy of the test calibration is determined by the accuracy of the reference balance and current technology allows for reference balances to be calibrated to within .+-.0.05%, the entire system has an accuracy of a .+-.0.2%. The entire apparatus is relatively small and can be mounted on a movable base for easy transport between test locations. The system can also accept a wide variety of reference balances, thus allowing calibration under diverse load and size requirements
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