52,944 research outputs found
Electrochemical behavior of 0.2 to 3 molar ferrous chloride-ferric chloride mixtures on edge-on pyrolytic graphite rotated disk electrodes
Potentiostatic determinations in various mixtures of FeCl2-FeCl3 with excess HCl show rest potentials that are 0.1 V less electropositive than the theoretical values from the formulated ratios of FeII to FeIII (probably as a result of complexing). The standard rate constant sub s. ranges between 0.0001 and 0.000 cm/sec. Tafel slopes b of roughly 0.12V per decade indicate single-electron exchange kinetics. No significant trend in either b or sub s was attributed to mixture composition. The higher sub s. values occurred with and edge-on pyrolytic graphite that had undergone a permanent surface change
2. Establishment of the School
The formal establishment of the New York State School of Industrial and Labor relations grew out of the thoughtful and vigorous action of a unique group of practical politicians who firmly believed, as they stated in their first report, that “Though we may legislate to the end of time, there will never be industrial peace and harmony without good faith, integrity, a high degree of responsibility, and a real desire to cooperate on the part of all parties concerned.
Impulse approximation in the n p --> d pi^0 reaction reexamined
The impulse approximation (one-body operator) in the n p --> d pi^0 reaction
is reexamined with emphasis on the issues of reducibility and recoil
corrections. An inconsistency when one pion exchange is included in the
production operator is demonstrated and then resolved via the introduction of
"wave function corrections" which nearly vanish for static nucleon propagators.
Inclusion of the recoil corrections to the nucleon propagators is found to
change the magnitude and sign of the impulse production amplitude, worsening
agreement with the experimental cross section by approximately 30%. A cutoff is
used to account for the phenomenological nature of the external wave functions,
and is found to have a significant impact up to approximately 2.5 GeV.Comment: Published versio
Homology of perfect complexes
It is proved that the sum of the Loewy lengths of the homology modules of a
finite free complex F over a local ring R is bounded below by a number
depending only on R. This result uncovers, in the structure of modules of
finite projective dimension, obstructions to realizing R as a closed fiber of
some flat local homomorphism. Other applications include, as special cases,
uniform proofs of known results on free actions of elementary abelian groups
and of tori on finite CW complexes. The arguments use numerical invariants of
objects in general triangulated categories, introduced here and called levels.
They allow one to track, through changes of triangulated categories,
homological invariants like projective dimension, as well as structural
invariants like Loewy length. An intermediate result sharpens, with a new
proof, the New Intersection Theorem for commutative algebras over fields. Under
additional hypotheses on the ring stronger estimates are proved for Loewy
lengths of modules of finite projective dimension.Comment: This version corrects an error in the statement (and proof) of
Theorem 7.4 in the published version of the paper [Adv. Math. 223 (2010)
1731--1781]. These changes do not affect any other results or proofs in the
paper. A corrigendum has been submitted
A Chandra Survey of the X-ray Properties of Broad Absorption Line Radio-Loud Quasars
This work presents the results of a Chandra study of 21 broad absorption line
(BAL) radio-loud quasars (RLQs). We conducted a Chandra snapshot survey of 12
bright BAL RLQs selected from SDSS/FIRST data and possessing a wide range of
radio and CIV absorption properties. Optical spectra were obtained nearly
contemporaneously with the Hobby-Eberly Telescope; no strong flux or BAL
variability was seen between epochs. We also include in our sample 9 additional
BAL RLQs possessing archival Chandra coverage. We compare the properties of
(predominantly high-ionization) BAL RLQs to those of non-BAL RLQs as well as to
BAL radio-quiet quasars (RQQs) and non-BAL RQQs for context.
All 12 snapshot and 8/9 archival BAL RLQs are detected, with observed X-ray
luminosities less than those of non-BAL RLQs having comparable optical/UV
luminosities by typical factors of 4.1-8.5. (BAL RLQs are also X-ray weak by
typical factors of 2.0-4.5 relative to non-BAL RLQs having both comparable
optical/UV and radio luminosities.) However, BAL RLQs are not as X-ray weak
relative to non-BAL RLQs as are BAL RQQs relative to non-BAL RQQs. While some
BAL RLQs have harder X-ray spectra than typical non-BAL RLQs, some have
hardness ratios consistent with those of non-BAL RLQs, and there does not
appear to be a correlation between X-ray weakness and spectral hardness, in
contrast to the situation for BAL RQQs. RLQs are expected to have X-ray
continuum contributions from both disk-corona and small-scale jet emission.
While the entire X-ray continuum in BAL RLQs cannot be obscured to the same
degree as in BAL RQQs, we calculate that the jet is likely partially covered in
many BAL RLQs. We comment briefly on implications for geometries and source
ages in BAL RLQs.Comment: 48 pages, 5 tables, 14 figures, accepted by Ap
THE ECONOMICS OF RIPARIAN MANAGEMENT: A LITERATURE REVIEW
Resource /Energy Economics and Policy,
SONTRAC: an imaging spectrometer for solar neutrons
An instrument capable of unambiguously determining the energy and direction of incident neutrons has important applications in solar physics-as well as environmental monitoring and medical/radiological sciences. The SONTRAC (SOlar Neutron TRACking) instrument is designed to operate in the neutron energy range of 20-250 MeV. The measurement principle is based on non-relativistic double scatter of neutrons off ambient protons (n-p scattering) within a block of densely packed scintillating fibers. Using this double-scatter mode it is possible to uniquely determine neutron energy and direction on an event-by-event basis. A fully operational science model of such an instrument has been built using 300 μm (250 μm active) scintillating fibers. The science model consists of a 5×5×5 cm cube of orthogonal plastic scintillating fiber layers. Two orthogonal imaging chains, employing image intensifiers and CCD cameras, allow full 3-dimensional reconstruction of scattered proton particle tracks. We report the results of the science model instrument calibration using 35-65 MeV protons. The proton calibration is the first step toward understanding the instrument response to n-p scatter events. Preliminary results give proton energy resolution of 2% (6%) at 67.5 (35) MeV, and angular resolution of 2° (4.5°) at 67.5 (35) MeV. These measurements are being used to validate detailed instrument simulations that will be used to optimize the instrument design and develop quantitative estimates of science return. Based on the proton calibration, neutron energy and angular resolution for a 10×10×10 cm version of SONTRAC is expected to be ~5% an
Finding the Silver Linings of the Cyberattack
Our project aimed to identify the effects of the UVM Health Network cyberattack and subsequent month-long network downtime on the South Burlington Family Medicine providers and clinic staff. We interviewed staff members about positive adaptations made by the team during the downtime, and inquired whether they planned to keep maintaining any of these changes once the electronic systems returned.https://scholarworks.uvm.edu/fmclerk/1703/thumbnail.jp
South African Corporations and post-Apartheid Expansion in Africa – creating a new regional space
The defeat of Apartheid in 1994 liberated not only South Africa’s internal political processes but also its economic relations with neighbouring countries in the Southern African Development Community (SADC). A key outcome was the surge of South African capital northward after years of dampened large scale investment because of legal sanction and more informal regulation. By the early 2000s, South African mining and industrial corporations, financial institutions and even some medium-sized enterprises have once again asserted their role as a dominant force in the SADC region. South Africa’s economic expansion is sometimes portrayed as a one-way process, where local environments and communities are passive recipients of SouthAfrican-led interventions. But evidence increasingly suggests that penetration of the region is highly contested by host countries, and sometimes actively and effectively resisted at local level. In other words, elements of both ‘sub-imperialism’ and local subversion are at play
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