892 research outputs found
Characterization and washability studies of raw coal from the Little Tonzona Field, Alaska
Coal occurs in an isolated exposure of Tertiary, non-marine sedimentary rocks
along the southwest bank of the Little Tonzona River, near Farewell, Alaska. The Little Tonzona River coal field is located approximately 150 air miles northwest of Anchorage, Alaska, and 210 air miles southwest of Fairbanks, Alaska; near the boundaries of Denali National Park. The Alaska Railroad and the Parks Highway are approximately 100 air miles from the coal field at their nearest point. The village of McGrath, on the Kuskokwim River, is located approximately 90 miles to the west (1).
An impressive outcrop of coal-bearing Tertiary sediments is exposed for a distance
of more than 275 feet on the west bank of the Little Tonzona River (Figure 1). More than
seven coal beds, ranging in thickness from 3 feet ta 30 feet, with a cumulative thickness of
over 134 feet, are interbedded with clay beds up to 40 feet thick. The clays are fine textured,
extremely plastic, light grey to nearly white bentonites andlor tonsteins.
Doyon Ltd., an ANSCA Native Corporation, holds land selections covering the
inferred limits of the coal field. During 1980 and 1981, Doyon entered into exploration
agreements with McIntyre Mines Inc. of Nevada. The two season exploration program
took place from June 1,1980 through August 22,1980 and from May 27,1981 through August
22, 1981. During the 1980 field season, geologic mapping, prospecting, stratigraphy,
trenching and bulk sampling of all coal outcrops were performed. This produced a total of
34 samples, which were taken for analysis. In 1981, six diamond drill holes with a
cumulative length of 2,935 feet were completed. Core recovery was close to 90%, and a total
of 147 coal samples, which represented 802.8 cumulative feet of coal, were taken for
analysis.
The exploration program confirmed a strike length of over 3 miles to the southwest
from the main river bank exposure. Northward extension is unknown at this time.
Although outcrop exposure is poor away from the river banks, burnout zones resulting from
past coal bed fires form a resistant, recognizable on strike feature in the relatively
unindurated Tertialy sequence. The appearance of these burnout zones along strike is
often the only surface indication of the buried coal-bearing strata. Well preserved plant
fossil impressions in the baked clays date the deposit as probable Miocene (2).
Coal characterization and washability studies were performed on all coal samples
by the Mineral Industry Research Laboratory of the University of Alaska Fairbanks. This
work was conducted under the direction of Dr. P.D. Rao, Professor of Coal Technology.This study was conducted under the sponsorship of McIntyre Mines Ltd
An ansatz for the nonlinear Demkov-Kunike problem for cold molecule formation
We study nonlinear mean-field dynamics of ultracold molecule formation in the
case when the external field configuration is defined by the level-crossing
Demkov-Kunike model, characterized by a bell-shaped coupling and finite
variation of the detuning. Analyzing the fast sweep rate regime of the strong
interaction limit, which models a situation when the peak value of the coupling
is large enough and the resonance crossing is sufficiently fast, we construct a
highly accurate ansatz to describe the temporal dynamics of the molecule
formation in the mentioned interaction regime. The absolute error of the
constructed approximation is less than 3*10^-6 for the final transition
probability while at certain time points it might increase up to 10^-3.
Examining the role of the different terms in the constructed approximation, we
prove that in the fast sweep rate regime of the strong interaction limit the
temporal dynamics of the atom-molecule conversion effectively consists of the
process of resonance crossing, which is governed by a nonlinear equation,
followed by atom-molecular coherent oscillations which are basically described
by a solution of the linear problem, associated with the considered nonlinear
one.Comment: Accepted for publication in J. Contemp. Phys. (Armenian National
Academy of Sciences) 8 pages, 4 figure
The importance of animal welfare science and ethics to veterinary students in Australia and New Zealand
The study of animal welfare and ethics (AWE) as part of veterinary education is important due to increasing community concerns and expectations about this topic, global pressures regarding food security, and the requirements of veterinary accreditation, especially with respect to Day One Competences. To address several key questions regarding the attitudes to AWE of veterinary students in Australia and New Zealand (NZ), the authors surveyed the 2014 cohort of these students. The survey aimed (1) to reveal what AWE topics veterinary students in Australia and NZ consider important as Day One Competences, and (2) to ascertain how these priorities align with existing research on how concern for AWE relates to gender and stage of study. Students identified triage and professional ethics as the most important Day One Competences in AWE. Students ranked an understanding of triage as increasingly important as they progressed through their program. Professional ethics was rated more important by early and mid-stage students than by senior students. Understanding the development of animal welfare science and perspectives on animal welfare were rated as being of little importance to veterinary graduates as Day One Competences, and an understanding of “why animal welfare matters” declined as the students progressed through the program. Combined, these findings suggest that veterinary students consider it more important to have the necessary practical skills and knowledge to function as a veterinarian on their first day in practic
Parity-violating neutron spin rotation in hydrogen and deuterium
We calculate the (parity-violating) spin rotation angle of a polarized
neutron beam through hydrogen and deuterium targets, using pionless effective
field theory up to next-to-leading order. Our result is part of a program to
obtain the five leading independent low-energy parameters that characterize
hadronic parity-violation from few-body observables in one systematic and
consistent framework. The two spin-rotation angles provide independent
constraints on these parameters. Using naive dimensional analysis to estimate
the typical size of the couplings, we expect the signal for standard target
densities to be 10^-7 to 10^-6 rad/m for both hydrogen and deuterium targets.
We find no indication that the nd observable is enhanced compared to the np
one. All results are properly renormalized. An estimate of the numerical and
systematic uncertainties of our calculations indicates excellent convergence.
An appendix contains the relevant partial-wave projectors of the three-nucleon
system.Comment: 44 pages, 17 figures; minor corrections; to be published in EPJ
Low-Temperature Specific Heat of an Extreme-Type-II Superconductor at High Magnetic Fields
We present a detailed study of the quasiparticle contribution to the
low-temperature specific heat of an extreme type-II superconductor at high
magnetic fields. Within a T-matrix approximation for the self-energies in the
mixed state of a homogeneous superconductor, the electronic specific heat is a
linear function of temperature with a linear- coefficient
being a nonlinear function of magnetic field . In the range of magnetic
fields H\agt (0.15-0.2)H_{c2} where our theory is applicable, the calculated
closely resembles the experimental data for the borocarbide
superconductor YNiBC.Comment: 7 pages, 2 figures, to appear in Physical Review
Categorizing Different Approaches to the Cosmological Constant Problem
We have found that proposals addressing the old cosmological constant problem
come in various categories. The aim of this paper is to identify as many
different, credible mechanisms as possible and to provide them with a code for
future reference. We find that they all can be classified into five different
schemes of which we indicate the advantages and drawbacks.
Besides, we add a new approach based on a symmetry principle mapping real to
imaginary spacetime.Comment: updated version, accepted for publicatio
The Planetary Nebula Luminosity Function at the Dawn of Gaia
The [O III] 5007 Planetary Nebula Luminosity Function (PNLF) is an excellent
extragalactic standard candle. In theory, the PNLF method should not work at
all, since the luminosities of the brightest planetary nebulae (PNe) should be
highly sensitive to the age of their host stellar population. Yet the method
appears robust, as it consistently produces < 10% distances to galaxies of all
Hubble types, from the earliest ellipticals to the latest-type spirals and
irregulars. It is therefore uniquely suited for cross-checking the results of
other techniques and finding small offsets between the Population I and
Population II distance ladders. We review the calibration of the method and
show that the zero points provided by Cepheids and the Tip of the Red Giant
Branch are in excellent agreement. We then compare the results of the PNLF with
those from Surface Brightness Fluctuation measurements, and show that, although
both techniques agree in a relative sense, the latter method yields distances
that are ~15% larger than those from the PNLF. We trace this discrepancy back
to the calibration galaxies and argue that, due to a small systematic error
associated with internal reddening, the true distance scale likely falls
between the extremes of the two methods. We also demonstrate how PNLF
measurements in the early-type galaxies that have hosted Type Ia supernovae can
help calibrate the SN Ia maximum magnitude-rate of decline relation. Finally,
we discuss how the results from space missions such as Kepler and Gaia can help
our understanding of the PNLF phenomenon and improve our knowledge of the
physics of local planetary nebulae.Comment: 12 pages, invited review at the conference "The Fundamental Cosmic
Distance Scale: State of the Art and Gaia Perspective", to appear in
Astrophysics and Space Scienc
Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA
Deep-inelastic positron-proton interactions at low values of Bjorken-x down
to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons
are studied with the H1 experiment at HERA. The inclusive cross section for
pi^0 mesons produced at small angles with respect to the proton remnant (the
forward region) is presented as a function of the transverse momentum and
energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x.
Measurements are also presented of the transverse energy flow in events
containing a forward pi^0 meson. Hadronic final state calculations based on QCD
models implementing different parton evolution schemes are confronted with the
data.Comment: 27 pages, 8 figures and 3 table
Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up
Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated
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