energy cascade
110
energy cascade in general the motions in the sea cover a wide range offrequencies, from gradually varying currents to small-scale rapidly changing turbulent eddies. The distribution of kinetic energy over this frequency range can
be presented as an energy spectrum of ocean motions. In this spectrum,
energy is exchanged between different frequency bands. Most energy is fed
in the large-scale motions by the air-sea exchange and the tides, and the energy
is dissipated in the small-scale motions where it is irreversibly converted
into heat (see Kolmogoroff length, ~inertial subrange). The flow of energy
from large to small scales is indicated by the term "energy cascade".
energy from the sea the sea takes part in the energy cycle of the earth by accumulating and transporting energy received from the sun, the atmosphere,
and the tides, and dissipating it or returning it to the atmosphere or to outer
space. Various methods have been proposed to extract a small fraction of this
energy for human use. The main possible sources are thermal, wave, and tidal
energy. In the first case, the temperature difference of the water at different
depths is used to drive a thermal engine (Ocean Thermal Energy Conversion
or OTEC). In the second case, the kinetic energy of the waves is used and the
tidal energy is extracted by using the potential energy of the water in a basin
filled at high tide. Under present conditions energy from the sea is only economically feasible under special circumstances. Tidal energy is used in places
with a large tidal range (e.g., in the Rance estuary of Brittany in France).
enrichment ratio is in most cases equal to the distribution coefficient or concentration
factor; the first term is usually applied for sorption to sedimentary particles,
the second used in biological accumulation.
Enteropneusta ~Hemichordata.
enthalpy ~thermodynamics.
Entoprocta small phylum within the Lophophorata (~Iophophore) of minute,
almost exclusively marine, filter-feeding animals. The solitary or colonial
animals are sessile or commensal, look superficially much like Bryozoa, but
their ciliated tentacles form a horseshoe-shaped row around the mouth. The
U-shaped gut ends in the anus, which is lying inside the circle of tentacles
(hence the name of the phylum).
entrainment (1) (geol.) the process in which substances are incorporated in
solid matter during its formation; (2) (phys.) one-directional movement of
water through a boundary surface between two bodies of water with different properties such as a pycnocline. The entrained water mixes with the water
across the boundary, which thus changes its properties, while the water on
the other side of the boundary keeps its original properties. Entrainment
110
energy cascade in general the motions in the sea cover a wide range offrequencies, from gradually varying currents to small-scale rapidly changing turbulent eddies. The distribution of kinetic energy over this frequency range can
be presented as an energy spectrum of ocean motions. In this spectrum,
energy is exchanged between different frequency bands. Most energy is fed
in the large-scale motions by the air-sea exchange and the tides, and the energy
is dissipated in the small-scale motions where it is irreversibly converted
into heat (see Kolmogoroff length, ~inertial subrange). The flow of energy
from large to small scales is indicated by the term "energy cascade".
energy from the sea the sea takes part in the energy cycle of the earth by accumulating and transporting energy received from the sun, the atmosphere,
and the tides, and dissipating it or returning it to the atmosphere or to outer
space. Various methods have been proposed to extract a small fraction of this
energy for human use. The main possible sources are thermal, wave, and tidal
energy. In the first case, the temperature difference of the water at different
depths is used to drive a thermal engine (Ocean Thermal Energy Conversion
or OTEC). In the second case, the kinetic energy of the waves is used and the
tidal energy is extracted by using the potential energy of the water in a basin
filled at high tide. Under present conditions energy from the sea is only economically feasible under special circumstances. Tidal energy is used in places
with a large tidal range (e.g., in the Rance estuary of Brittany in France).
enrichment ratio is in most cases equal to the distribution coefficient or concentration
factor; the first term is usually applied for sorption to sedimentary particles,
the second used in biological accumulation.
Enteropneusta ~Hemichordata.
enthalpy ~thermodynamics.
Entoprocta small phylum within the Lophophorata (~Iophophore) of minute,
almost exclusively marine, filter-feeding animals. The solitary or colonial
animals are sessile or commensal, look superficially much like Bryozoa, but
their ciliated tentacles form a horseshoe-shaped row around the mouth. The
U-shaped gut ends in the anus, which is lying inside the circle of tentacles
(hence the name of the phylum).
entrainment (1) (geol.) the process in which substances are incorporated in
solid matter during its formation; (2) (phys.) one-directional movement of
water through a boundary surface between two bodies of water with different properties such as a pycnocline. The entrained water mixes with the water
across the boundary, which thus changes its properties, while the water on
the other side of the boundary keeps its original properties. Entrainment