3,191 research outputs found
The impact of a wave farm on large scale sediment transport
This study investigates the interactions of waves and tides at a wave farm in the southwest of England, in particular their effects on radiation stress, bottom stress, and consequently on the sediment transport and the coast adjacent to the wave-farm (the Wave Hub). In this study, an integrated complex numerical modelling system is setup at the Wave Hub site and is used to compute the wave and current fields by taking into account the wave-current interaction, as well as the sediment transport. Results show that tidal elevation and tidal currents have a significant effect on the wave height and direction predictions; tidal forcing and wind waves have a significant effect on the bed shear-stress, relevant to sediment transport; waves via radiation stresses have an important effect on the longshore and cross-shore velocity components, particularly during the spring tides. Waves can impact on bottom boundary layer and mixing in the water column. The results highlight the importance of the interactions between waves and tides when modelling coastal morphology with presence of wave energy devices
Darwin or Frankenstein?
Through sculpture and drawing, I create my own versions of natural specimens primarily based upon the visual unity of disparate organisms. Invented specimens are composed using a variety of processes employing a mixture of atypical materials following the (20th, 21st century) Postmodern shift away from formalist and traditional uses of any singular medium. As well as a variety of art materials, the specimens are hybrids of organic and biomorphic elements, blurring boundaries between botanical, animal, fungal, metal, and mineral. Is my approach perhaps like Charles Darwin, observant and studious naturalist, or am I more like Dr. Frankenstein, science fiction maker of monstrosities
Darwin or Frankenstein?
Through sculpture and drawing, I create my own versions of natural specimens primarily based upon the visual unity of disparate organisms. Invented specimens are composed using a variety of processes employing a mixture of atypical materials following the (20th, 21st century) Postmodern shift away from formalist and traditional uses of any singular medium. As well as a variety of art materials, the specimens are hybrids of organic and biomorphic elements, blurring boundaries between botanical, animal, fungal, metal, and mineral. Is my approach perhaps like Charles Darwin, observant and studious naturalist, or am I more like Dr. Frankenstein, science fiction maker of monstrosities
Contribution of the forelimbs and hindlimbs of the horse to mechanical energy changes in jumping
The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the leg behaved as a linear spring. During the forelimb push, the total energy first decreased by 3.2 J k
Generalized hydrodynamics of a dilute finite-sized particles suspension: Dynamic viscosity
We present a mesoscopic hydrodynamic description of the dynamics of colloidal
suspensions. We consider the system as a gas of Brownian particles suspended in
a Newtonian heat bath subjected to stationary non-equilibrium conditions
imposed by a velocity field. Using results already obtained in previous studies
in the field by means of a generalized Fokker-Planck equation, we obtain a set
of coupled differential equations for the local diffusion current and the
evolution of the total stress tensor. We find that the dynamic shear viscosity
of the system contains contributions arising from the finite size of the
particles.Comment: To appear in Physical Review
High-pressure x-ray diffraction study of bulk and nanocrystalline PbMoO4
We studied the effects of high-pressure on the crystalline structure of bulk
and nanocrystalline scheelite-type PbMoO4. We found that in both cases the
compressibility of the materials is highly non-isotropic, being the c-axis the
most compressible one. We also observed that the volume compressibility of
nanocrystals becomes higher that the bulk one at 5 GPa. In addition, at 10.7(8)
GPa we observed the onset of an structural phase transition in bulk PbMoO4. The
high-pressure phase has a monoclinic structure similar to M-fergusonite. The
transition is reversible and not volume change is detected between the low- and
high-pressure phases. No additional structural changes or evidence of
decomposition are found up to 21.1 GPa. In contrast nanocrystalline PbMoO4
remains in the scheelite structure at least up to 16.1 GPa. Finally, the
equation of state for bulk and nanocrystalline PbMoO4 are also determined.Comment: 18 pages, 4 figure
Lepton Number Violating Radiative Decay in Models with R-parity Violation
Models with explicit R-parity violation can induce new rare radiative decay
modes of the boson into single supersymmetric particles which also violate
lepton number. We examine the rate and signature for one such decay,
, and find that such a mode will be very difficult
to observe, due its small branching fraction, even if the lepton number
violating coupling in the superpotential is comparable in strength to
electromagnetism. This parallels a similar result obtained earlier by Hewett in
the case of radiative decays.Comment: 10 pages, 2 figures(available on request), LaTex, ANL-HEP-PR-92-8
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