88 research outputs found
Assessment of simple filter systems for treating run-off from seasonal livestock areas
Non-Peer ReviewedCattle wintering sites and calving grounds are frequently located on dissected terrain. In many of these areas there is a high risk of contamination to stream headwaters from on-site run-off, particularly in the spring. A literature review suggested a number of small- or municipal-scale filter treatments that may have potential for treating run-off in terms of reducing nutrient and pathogen concentrations. If effective, such systems may provide a low-cost, low-maintenance system for treating run-off in these situations. A two-year bench scale trial was initiated in 2006 at two sites to test the effectiveness of four filter technologies. The technologies were chosen based on several criteria which included: capital and maintenance costs, simplicity, known effectiveness, space requirements, and the ability to scale down the technology. The four selected filters were: demand-operated slow sand filter, intermittent flow sand filter, intermittent flow wood chip filter, and continuous flow rock filter. The trial and filters are described and preliminary results obtained starting in July, 2006 are presented. First year results suggest that the slow sand filter is not a viable technology but the intermittent flow filters and the rock filter show promise
Phonon `notches' in a-b -plane optical conductivity of high-Tc superconductors
It is shown that a correlation between the positions of the -axis
longitudinal optic () phonons and ``notch''-like structures in the
- plane conductivity of high- superconductors results from
phonon-mediated interaction between electrons in different layers. It is found
that the relative size of the notches depends on
, where ,
and are the effective coupling strength, the frequency and the
width of the optical phonon which is responsible for the notch. Even for
the effect can be large if the phonon is very sharp.Comment: 5 pages, REVTeX, 4 uuencoded figure
Scaling of transition temerature and CuO_2 plane buckling in the cuprate superconductors
Recently it is seen\cite{Nature},that both and the buckling of the
planes goes through a maximum at the same doping level. We show that
only for optimal doping concentration the Fermi surface touches the M()
point in the BZ, where the matrix element for interlayer pair tunneling
amplitude is largest, so that the gain in delocalization energy by tunneling(in
pairs) along the axis is largest. Buckling of the planes on the other hand
modulates the separation between the planes and thereby modulates the
interlayer pair tunneling amplitude. That is why both and buckling
angle(Oxygen atom displacement out of the plane) scales the same way with
doping concentration. We have calculated and buckling angle for
various doping concentration. The agreement with experiment is remarkably good.
We also point out the possible reason for large(about 1 percent) change of the
buckling mode phonon frequency, accross the transition temperature. scatteringComment: Summitted to Physics C, Journal of Superconductivity, 6 pages Tex
file with 4 postscript files attache
Moral distress in emergency departments : experiences of registered nurses
The purpose of the study is to determine whether registered nurses are experiencing moral distress while working in emergency departments, and if so, the causes and their reactions to the phenomenon. Registered nurses currently employed in an in emergency department engaged in semi-structured interviews to examine the phenomenon. This study utilized narrative inquiry research design as advocated by Reissman (2008). Findings indicated that registered nurses are experiencing moral distress in emergency departments related to myriad pressures and demands forcing simultaneous decisions primarily related to use of the finite number of resources at their disposal and the provision of futile care. Participants’ reactions to moral distress included acknowledging that they will continue to find themselves in morally distressing situations, passion for their jobs despite encountering morally stressing situations, and an ability to manage negative effects of moral distress related to their personalities and the nature of the working relationships that exist within emergency departments. Findings indicate that health care administrators, staff, and physicians require increased awareness of the phenomenon if they wish to address and mitigate these situations
Riparian buffer design tool for cropland: lotic systems
Non-Peer ReviewedRiparian areas function as a buffer between the upland and the aquatic systems. This area is
unique in its structure and the services it provides intercepting non-point source (NPS) pollution
from the upland. In some cases additional buffer width may be required or sought. Riparian
buffer strips are a beneficial management practice (BMP) eligible for cost-shared funding under
government programs. However, little information is available to assist landowners in
appropriate location or design considerations. This project aims to create a riparian buffer design
tool to be utilized on lotic (flowing water) systems in cropland settings. This tool will consist of
a flow chart and accompanying key. The flow chart along with air photographs, soils maps and
discussions with the landowner will help to determine where on the landscape a buffer should be
located. The final product will include case studies and guiding documents for technical staff to
utilize when assisting landowners with their riparian buffer strips
Polarized far-infrared and Raman spectra of SrCuO2 single crystals
We measured polarized far-infrared reflectivity and Raman scattering spectra
of SrCuO single crystals. The frequencies for infrared-active modes were
determined using an oscillator-fitting procedure of reflectivity data. The
Raman spectra were measured at different temperatures using several laser
energies . In addition to eight of twelve Raman active modes,
predicted by factor-group analysis, we observed a complex structure in the
Raman spectra for polarization parallel to the {\bf c}-axis, which consists of
Raman-allowed A symmetry modes, and B LO infrared-active
(Raman-forbidden) modes of the first and higher order as well as their
combinations. The Raman-forbidden modes have a stronger intensity at higher
than the Raman-allowed ones. In order to explain this resonance
effect, we measured the dielectric function and optical reflection spectra of
SrCuO in the visible range. We show that the Raman-allowed A symmetry
modes are resonantly enhanced when a laser energy is close to , while
Raman-forbidden (IR-active) modes resonate strongly for laser line energies
close to the electronic transition of higher energy gaps.Comment: to be published in Physica
Heavy-Fermion Formation at the Metal-to-Insulator Transition in GdSrTiO
The perovskite-like transition-metal oxide GdSrTiO is
investigated by measurements of resistivity, specific-heat, and electron
paramagnetic resonance (EPR). Approaching the metal-to-insulator transition
from the metallic regime (), the Sommerfeld coefficient of
the specific heat becomes strongly enhanced and the resistivity increases
quadratically at low temperatures, which both are fingerprints of strong
electronic correlations. The temperature dependence of the dynamic
susceptibility, as determined from the Gd-EPR linewidth, signals the
importance of strong spin fluctuations, as observed in heavy-fermion compounds.Comment: 4pages, 3 figure
Phonons and Magnetic Excitations in Mott-Insulator LaTiO
The polarized Raman spectra of stoichiometric LaTiO (T K) were
measured between 6 and 300 K. In contrast to earlier report on half-metallic
LaTiO, neither strong background scattering, nor Fano shape of the
Raman lines was observed. The high frequency phonon line at 655 cm
exhibits anomalous softening below T: a signature for structural
rearrangement. The assignment of the Raman lines was done by comparison to the
calculations of lattice dynamics and the nature of structural changes upon
magnetic ordering are discussed. The broad Raman band, which appears in the
antiferromagnetic phase, is assigned to two-magnon scattering. The estimated
superexchange constant meV is in excellent agreement with the
result of neutron scattering studies.Comment: 4 pages, 5 figure
Low-Temperature Phase of the CdReO Superconductor: Ab initio Phonon Calculations and Raman Scattering
Using an {\it ab initio} approach, we report a phonon soft mode in the
tetragonal structure described by the space group of the K
superconductor CdReO. It induces an orthorhombic distortion to a
crystal structure described by the space group which hosts the
superconducting state. This new phase has a lower total energy than the other
known crystal structures of CdReO. Comprehensive temperature
dependent Raman scattering experiments on isotope enriched samples,
CdReO, not only confirm the already known structural
phase transitions but also allow us to identify a new characteristic
temperature regime around K, below which the Raman spectra undergo
remarkable changes with the development of several sharp modes and mode
splitting. Together with the results of the \textit{ab initio} phonon
calculations we take these observations as strong evidence for another phase
transition to a novel low-temperature crystal structure of CdReO.Comment: 7 pages, 8 figure
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