5,581 research outputs found
A study of poultry processing plant noise characteristics and potential noise control techniques
The noise environment in a typical poultry processing plant was characterized by developing noise contours for two representative plants: Central Soya of Athens, Inc., Athens, Georgia, and Tip Top Poultry, Inc., Marietta, Georgia. Contour information was restricted to the evisceration are of both plants because nearly 60 percent of all process employees are stationed in this area during a normal work shift. Both plant evisceration areas were composed of tile walls, sheet metal ceilings, and concrete floors. Processing was performed in an assembly-line fashion in which the birds travel through the area on overhead shackles while personnel remain at fixed stations. Processing machinery was present throughout the area. In general, the poultry processing noise problem is the result of loud sources and reflective surfaces. Within the evisceration area, it can be concluded that only a few major sources (lung guns, a chiller component, and hock cutters) are responsible for essentially all direct and reverberant sound pressure levels currently observed during normal operations. Consequently, any effort to reduce the noise problem must first address the sound power output of these sources and/or the absorptive qualitities of the room
Computational Design of Chemical Nanosensors: Metal Doped Carbon Nanotubes
We use computational screening to systematically investigate the use of
transition metal doped carbon nanotubes for chemical gas sensing. For a set of
relevant target molecules (CO, NH3, H2S) and the main components of air (N2,
O2, H2O), we calculate the binding energy and change in conductance upon
adsorption on a metal atom occupying a vacancy of a (6,6) carbon nanotube.
Based on these descriptors, we identify the most promising dopant candidates
for detection of a given target molecule. From the fractional coverage of the
metal sites in thermal equilibrium with air, we estimate the change in the
nanotube resistance per doping site as a function of the target molecule
concentration assuming charge transport in the diffusive regime. Our analysis
points to Ni-doped nanotubes as candidates for CO sensors working under typical
atmospheric conditions
Little boxes: A simple implementation of the Greenberger, Horne, and Zeilinger result for spatial degrees of freedom
A Greenberger, Horne, and Zeilinger-type construction is realized in the position properties of three particles whose wavefunctions are distributed over three two-chambered boxes. The same system is modeled more realistically using three spatially separated, singly ionized hydrogen molecules. © 2011 American Association of Physics Teachers
Cardiovascular-renal axis disorders in the domestic dog and cat: a veterinary consensus statement
OBJECTIVES
There is a growing understanding of the complexity of interplay between renal and cardiovascular systems in both health and disease. The medical profession has adopted the term "cardiorenal syndrome" (CRS) to describe the pathophysiological relationship between the kidney and heart in disease. CRS has yet to be formally defined and described by the veterinary profession and its existence and importance in dogs and cats warrant investigation. The CRS Consensus Group, comprising nine veterinary cardiologists and seven nephrologists from Europe and North America, sought to achieve consensus around the definition, pathophysiology, diagnosis and management of dogs and cats with "cardiovascular-renal disorders" (CvRD). To this end, the Delphi formal methodology for defining/building consensus and defining guidelines was utilised.
METHODS
Following a literature review, 13 candidate statements regarding CvRD in dogs and cats were tested for consensus, using a modified Delphi method. As a new area of interest, well-designed studies, specific to CRS/CvRD, are lacking, particularly in dogs and cats. Hence, while scientific justification of all the recommendations was sought and used when available, recommendations were largely reliant on theory, expert opinion, small clinical studies and extrapolation from data derived from other species.
RESULTS
Of the 13 statements, 11 achieved consensus and 2 did not. The modified Delphi approach worked well to achieve consensus in an objective manner and to develop initial guidelines for CvRD.
DISCUSSION
The resultant manuscript describes consensus statements for the definition, classification, diagnosis and management strategies for veterinary patients with CvRD, with an emphasis on the pathological interplay between the two organ systems. By formulating consensus statements regarding CvRD in veterinary medicine, the authors hope to stimulate interest in and advancement of the understanding and management of CvRD in dogs and cats. The use of a formalised method for consensus and guideline development should be considered for other topics in veterinary medicine
IS THE MANCHESTER MOBILITY SCORE A VALID AND RELIABLE MEASURE OF PHYSICAL FUNCTION WITHIN THE INTENSIVE CARE UNIT
Entanglement of distant optomechanical systems
We theoretically investigate the possibility to generate non-classical states
of optical and mechanical modes of optical cavities, distant from each other. A
setup comprised of two identical cavities, each with one fixed and one movable
mirror and coupled by an optical fiber, is studied in detail. We show that with
such a setup there is potential to generate entanglement between the distant
cavities, involving both optical and mechanical modes. The scheme is robust
with respect to dissipation, and nonlocal correlations are found to exist in
the steady state at finite temperatures.Comment: 12 pages (published with minor modifications
Molecular formations in ultracold mixtures of interacting and noninteracting atomic gases
Atom-molecule equilibrium for molecular formation processes is discussed for
boson-fermion, fermion-fermion, and boson-boson mixtures of ultracold atomic
gases in the framework of quasichemical equilibrium theory. After presentation
of the general formulation, zero-temperature phase diagrams of the
atom-molecule equilibrium states are calculated analytically; molecular, mixed,
and dissociated phases are shown to appear for the change of the binding energy
of the molecules. The temperature dependences of the atom or molecule densities
are calculated numerically, and finite-temperature phase structures are
obtained of the atom-molecule equilibrium in the mixtures. The transition
temperatures of the atom or molecule Bose-Einstein condensations are also
evaluated from these results. Quantum-statistical deviations of the law of mass
action in atom-molecule equilibrium, which should be satisfied in mixtures of
classical Maxwell-Boltzmann gases, are calculated, and the difference in the
different types of quantum-statistical effects is clarified. Mean-field
calculations with interparticle interactions (atom-atom, atom-molecule, and
molecule-molecule) are formulated, where interaction effects are found to give
the linear density-dependent term in the effective molecular binding energies.
This method is applied to calculations of zero-temperature phase diagrams,
where new phases with coexisting local-equilibrium states are shown to appear
in the case of strongly repulsive interactions.Comment: 35 pages, 14 figure
Could humans recognize odor by phonon assisted tunneling?
Our sense of smell relies on sensitive, selective atomic-scale processes that
are initiated when a scent molecule meets specific receptors in the nose.
However, the physical mechanisms of detection are not clear. While odorant
shape and size are important, experiment indicates these are insufficient. One
novel proposal suggests inelastic electron tunneling from a donor to an
acceptor mediated by the odorant actuates a receptor, and provides critical
discrimination. We test the physical viability of this mechanism using a simple
but general model. Using values of key parameters in line with those for other
biomolecular systems, we find the proposed mechanism is consistent both with
the underlying physics and with observed features of smell, provided the
receptor has certain general properties. This mechanism suggests a distinct
paradigm for selective molecular interactions at receptors (the swipe card
model): recognition and actuation involve size and shape, but also exploit
other processes.Comment: 10 pages, 1 figur
Partition function of two- and three-dimensional Potts ferromagnets for arbitrary values of q>0
A new algorithm is presented, which allows to calculate numerically the
partition function Z_q of the d-dimensional q-state Potts models for arbitrary
real values q>0 at any given temperature T with high precision. The basic idea
is to measure the distribution of the number of connected components in the
corresponding Fortuin-Kasteleyn representation and to compare with the
distribution of the case q=1 (graph percolation), where the exact result Z_1=1
is known.
As application, d=2 and d=3-dimensional ferromagnetic Potts models are
studied, and the critical values q_c, where the transition changes from second
to first order, are determined. Large systems of sizes N=1000^2 respectively
N=100^3 are treated. The critical value q_c(d=2)=4 is confirmed and
q_c(d=3)=2.35(5) is found.Comment: 4 pages, 4 figures, RevTe
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