2,908 research outputs found
Animal Efficiency in an Intensive Beef Production System
A stochastic input distance function is estimated to analyse the efficiency with which physical characteristics of individual lot-fed beef cattle in Australia are combined with conventional inputs to produce a final product possessing defined quality attributes. High mean technical efficiency estimates are reported for all animals and by breed. All partial output elasticities with respect to inputs are of expected sign. Of four outputs included in the analysis, carcass weight and moisture retention in meat after cooking have highly significant coefficients of expected sign, but two meat quality variables have coefficients of unexpected sign indicating that they decline as inputs increase. Some evidence is detected of scope economies between moisture retention in meat and the inverse of meat compression.efficiency, intensive agriculture, scope economies, Livestock Production/Industries, Q12, C51,
Fully quantum mechanical dynamic analysis of single-photon transport in a single-mode waveguide coupled to a traveling-wave resonator
We analyze the dynamics of single photon transport in a single-mode waveguide
coupled to a micro-optical resonator using a fully quantum mechanical model. We
examine the propagation of a single-photon Gaussian packet through the system
under various coupling conditions. We review the theory of single photon
transport phenomena as applied to the system and we develop a discussion on the
numerical technique we used to solve for dynamical behavior of the quantized
field. To demonstrate our method and to establish robust single photon results,
we study the process of adiabatically lowering or raising the energy of a
single photon trapped in an optical resonator under active tuning of the
resonator. We show that our fully quantum mechanical approach reproduces the
semi-classical result in the appropriate limit and that the adiabatic invariant
has the same form in each case. Finally, we explore the trapping of a single
photon in a system of dynamically tuned, coupled optical cavities.Comment: 24 pages, 10 figure
An Immersed Boundary method with divergence-free velocity interpolation and force spreading
The Immersed Boundary (IB) method is a mathematical framework for
constructing robust numerical methods to study fluid-structure interaction in
problems involving an elastic structure immersed in a viscous fluid. The IB
formulation uses an Eulerian representation of the fluid and a Lagrangian
representation of the structure. The Lagrangian and Eulerian frames are coupled
by integral transforms with delta function kernels. The discretized IB
equations use approximations to these transforms with regularized delta
function kernels to interpolate the fluid velocity to the structure, and to
spread structural forces to the fluid. It is well-known that the conventional
IB method can suffer from poor volume conservation since the interpolated
Lagrangian velocity field is not generally divergence-free, and so this can
cause spurious volume changes. In practice, the lack of volume conservation is
especially pronounced for cases where there are large pressure differences
across thin structural boundaries. The aim of this paper is to greatly reduce
the volume error of the IB method by introducing velocity-interpolation and
force-spreading schemes with the properties that the interpolated velocity
field in which the structure moves is at least C1 and satisfies a continuous
divergence-free condition, and that the force-spreading operator is the adjoint
of the velocity-interpolation operator. We confirm through numerical
experiments in two and three spatial dimensions that this new IB method is able
to achieve substantial improvement in volume conservation compared to other
existing IB methods, at the expense of a modest increase in the computational
cost. Further, the new method provides smoother Lagrangian forces (tractions)
than traditional IB methods. The method presented here is restricted to
periodic computational domains. Its generalization to non-periodic domains is
important future work.Comment: 49 pages, 13 figure
Natural abundance solid-state 33S NMR study of NbS3: applications for battery conversion electrodes.
We report ultra-wideline, high-field natural abundance solid-state 33S NMR spectra of the Li-ion battery conversion electrode NbS3, the first 33S NMR study of a compound containing disulfide (S22-) units. The large quadrupolar coupling parameters (CQ ≈ 31 MHz) are consistent with values obtained from DFT calculations, and the spectra provide evidence for the linear Peierls distortion that doubles the number of 33S sites
Spatial variability of precipitation regimes over Turkey
Turkish annual precipitation regimes are analysed to provide large-scale perspective and redefine precipitation regions. Monthly total precipitation data are employed for 107 stations (1963–2002). Precipitation regime shape (seasonality) and magnitude (size) are classified using a novel multivariate methodology. Six shape and five magnitude classes are identified, which exhibit clear spatial structure. A composite (shape and magnitude) regime classification reveals dominant controls on spatial variability of precipitation. Intra-annual timing and magnitude of precipitation is highly variable due to seasonal shifts in Polar and Subtropical zones and physiographic factors. Nonetheless, the classification methodology is shown to be a powerful tool that identifies physically-interpretable precipitation regions: (1) coastal regimes for Marmara, coastal Aegean, Mediterranean and Black Sea; (2) transitional regimes in continental Aegean and Southeast Anatolia; and (3) inland regimes across central and Eastern Anatolia. This research has practical implications for understanding water resources, which are under ever growing pressure in Turkey
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