3,934 research outputs found
Issued as a Part of Progress Report No. 13 of The Investigation of Prestressed Reinforced Concrete for Highway Bridges; Project IHR-10, Illinois Cooperative Highway Research Program
The Division of Highways. State of Illinois.The Bureau of Public Roads. U.S. Department of Commerc
Small angle neutron scattering (SANS) studies of diffusion in bulk polystyrene near the glass transition temperature (Tg)
Ultraslow diffusion in bulk polymers has been measured by SANS. The experiment begins by measuring scattering from heterogeneous specimens containing domains of protonatedâand deuteratedâpolymers at temperatures far below Tg. The samples are subsequently held [annealed] above Tg for a known timeâinterval, then cooled below Tg where SANS is measured again. Scattering changes, from before to after annealing, are analysed to obtain diffusion coefficients. The recent Summerfield â Ullman procedure is used to deconvolute portions of the scattering curve that decrease and increase with annealing time. Because of SANS sensitivity to small distances, the method yields D â 10â18 to 10â15 cm2/s after annealing times of 1â24 h. Data analysis is complicated by âsmearing effectsâ which produce apparent Qâdependent diffusion coefficients. Representative experimental results on polystyrene at 108°â130°C are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112190/1/19880150127_ftp.pd
Clinical Utility of the MMPI-2-RF Hierarchical Description:An Illustration in Cluster C Personality Disorder Patients
Several studies have addressed the associations between the Minnesota Multiphasic Personality Inventory-2 Restructured form (MMPI-2-RF; Ben-Porath & Tellegen, 2008) scale scores and the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association, 2013) Section II personality disorder (PD) criterion counts. While these studies showed which variables were associated with the PDs as well as their combined predictive potency, no information is available on mean patterns of elevation associated with these conditions. To illustrate how the MMPI-2-RF information may amplify categorical diagnostic information, we describe the mean RF profiles of a psychiatric sample with a Cluster C PD diagnosis. PD classification was based on the Structured Clinical Interview for the DSM-IV (SCID-II). Patterns of elevation across the three levels of the MMPI-2-RF scale sets were consistently in line with theoretical expectation. In addition, elevated scores on somatic/cognitive scales were noted. It is concluded that the MMPI-2-RF can enhance DSM Personality disorder model description.</p
Observation of hypertritons in Au+Au collisions at \sqrt{s_{NN}} = 200 GeV
We report preliminary results of hypertriton observation in heavy-ion
collisions at RHIC. We have identified 157 +- 30 candidates in the current
sample containing ~10^8 Au+Au events at \sqrt{s_{NN}} = 200 GeV. The production
rate of hypertriton is close to that of helium 3. No extra penalty factor is
observed for hypertriton, in contrast to results observed at the AGS.Comment: Turn off the line number package for QM09 proceeding publicatio
Correcting for Distortions due to Ionization in the STAR TPC
Physics goals of the STAR Experiment at RHIC in recent (and future) years
drive the need to operate the STAR TPC at ever higher luminosities, leading to
increased ionization levels in the TPC gas. The resulting ionic space charge
introduces field distortions in the detector which impact tracking performance.
Further complications arise from ionic charge leakage into the main TPC volume
from the high gain anode region. STAR has implemented corrections for these
distortions based on measures of luminosity, which we present here.
Additionally, we highlight a novel approach to applying the corrections on an
event-by-event basis applicable in conditions of rapidly varying ionization
sources.Comment: 6 pages, 7 figures, proceedings of the Workshop on Tracking in High
Multiplicity Environments (TIME 05) in Zurich, Switzerland, submitted to
Nucl. Instr. and Meth.
Singlet and triplet bipolarons on the triangular lattice
We study the Coulomb-Fr\"ohlich model on a triangular lattice, looking in
particular at states with angular momentum. We examine a simplified model of
crab bipolarons with angular momentum by projecting onto the low energy
subspace of the Coulomb-Fr\"ohlich model with large phonon frequency. Such a
projection is consistent with large long-range electron-phonon coupling and
large repulsive Hubbard . Significant differences are found between the band
structure of singlet and triplet states: The triplet state (which has a flat
band) is found to be significantly heavier than the singlet state (which has
mass similar to the polaron). We test whether the heavier triplet states
persist to lower electron-phonon coupling using continuous time quantum Monte
Carlo (QMC) simulation. The triplet state is both heavier and larger,
demonstrating that the heavier mass is due to quantum interference effects on
the motion. We also find that retardation effects reduce the differences
between singlet and triplet states, since they reintroduce second order terms
in the hopping into the inverse effective mass.Comment: Proceedings of SNS 200
Deformation of the Planetary Orbits Caused by the Time Dependent Gravitational Potential in the Universe
In the paper are studied the deformations of the planetary orbits caused by
the time dependent gravitational potential in the universe. It is shown that
the orbits are not axially symmetric and the time dependent potential does not
cause perihelion precession. It is found a simple formula for the change of the
orbit period caused by the time dependent gravitational potential and it is
tested for two binary pulsars.Comment: 7 page
Cosmological Constraints on the Sign-Changeable Interactions
Recently, Cai and Su [Phys. Rev. D {\bf 81}, 103514 (2010)] found that the
sign of interaction in the dark sector changed in the approximate redshift
range of 0.45\,\lsim\, z\,\lsim\, 0.9, by using a model-independent method to
deal with the observational data. In fact, this result raises a remarkable
problem, since most of the familiar interactions cannot change their signs in
the whole cosmic history. Motivated by the work of Cai and Su, we have proposed
a new type of interaction in a previous work [H. Wei, Nucl. Phys. B {\bf 845},
381 (2011)]. The key ingredient is the deceleration parameter in the
interaction , and hence the interaction can change its sign when our
universe changes from deceleration () to acceleration (). In the
present work, we consider the cosmological constraints on this new type of
sign-changeable interactions, by using the latest observational data. We find
that the cosmological constraints on the model parameters are fairly tight. In
particular, the key parameter can be constrained to a narrow range.Comment: 15 pages, 1 table, 8 figures, revtex4; v2: published versio
Cartan subalgebras in C*-algebras of Hausdorff etale groupoids
The reduced -algebra of the interior of the isotropy in any Hausdorff
\'etale groupoid embeds as a -subalgebra of the reduced
-algebra of . We prove that the set of pure states of with unique
extension is dense, and deduce that any representation of the reduced
-algebra of that is injective on is faithful. We prove that there
is a conditional expectation from the reduced -algebra of onto if
and only if the interior of the isotropy in is closed. Using this, we prove
that when the interior of the isotropy is abelian and closed, is a Cartan
subalgebra. We prove that for a large class of groupoids with abelian
isotropy---including all Deaconu--Renault groupoids associated to discrete
abelian groups--- is a maximal abelian subalgebra. In the specific case of
-graph groupoids, we deduce that is always maximal abelian, but show by
example that it is not always Cartan.Comment: 14 pages. v2: Theorem 3.1 in v1 incorrect (thanks to A. Kumjain for
pointing out the error); v2 shows there is a conditional expectation onto
iff the interior of the isotropy is closed. v3: Material (including some
theorem statements) rearranged and shortened. Lemma~3.5 of v2 removed. This
version published in Integral Equations and Operator Theor
Classtalk: A Classroom Communication System for Active Learning
This pdf file is an article describing the advantages of using Classtalk technology in the classroom to enhance classroom communication. Classtalk technology cab facilitate the presentation of questions for small group work, collec the student answers and then display histograms showing how the class answered. This new communication technology can help instructors create a more interactive, student centered classroom, especially when teaching large courses. The article describes Classtalk as a very useful tool not only for engaging students in active learning, but also for enhancing the overall communication within the classroom. This article is a selection from the electronic Journal for Computing in Higher Education. Educational levels: Graduate or professional
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