7,729 research outputs found
CHANGE AND CONFLICT IN LAND AND WATER USE: RESOURCE VALUATION IN CONFLICT RESOLUTION AMONG COMPETING USERS
Resource /Energy Economics and Policy,
COASTAL ALABAMA RECREATIONAL LIVE BAIT STUDY
Recreational fishing is major industry and reasonably priced, high quality bait plays an important role in sustaining recreational fishing's popularity. This study provides a summary of Alabama's coastal live bait market including information on previous live bait studies and results of two surveys on the live bait shrimp, bull minnow and other bait markets. Results indicated there were periods of supply shortages, dealer willingness to pay more for shrimp that live longer and a dealers' use of multiple supply sources. Lost income was reported from not having live bait shrimp available for sale at peak demand periods. The economics of shrimp mariculture needs to be examined to determine its feasibility in augmenting the current supply of shrimp to the live bait industry.Resource /Energy Economics and Policy,
Identification of vortexes obstructing the dynamo mechanism in laboratory experiments
The magnetohydrodynamic dynamo effect explains the generation of
self-sustained magnetic fields in electrically conducting flows, especially in
geo- and astrophysical environments. Yet the details of this mechanism are
still unknown, e.g., how and to which extent the geometry, the fluid topology,
the forcing mechanism and the turbulence can have a negative effect on this
process. We report on numerical simulations carried out in spherical geometry,
analyzing the predicted velocity flow with the so-called Singular Value
Decomposition, a powerful technique that allows us to precisely identify
vortexes in the flow which would be difficult to characterize with conventional
spectral methods. We then quantify the contribution of these vortexes to the
growth rate of the magnetic energy in the system. We identify an axisymmetric
vortex, whose rotational direction changes periodically in time, and whose
dynamics are decoupled from those of the large scale background flow, is
detrimental for the dynamo effect. A comparison with experiments is carried
out, showing that similar dynamics were observed in cylindrical geometry. These
previously unexpected eddies, which impede the dynamo effect, offer an
explanation for the experimental difficulties in attaining a dynamo in
spherical geometry.Comment: 25 pages, 12 figures, submitted to Physics of Fluid
Analysis and Design of 3-Phase Unfolding Based AC-DC Battery Chargers
This thesis presents the analysis and design of high-efficiency battery chargers for heavy duty EV applications. The rise in popularity of the electric vehicles (EVs) due to their increased efficiency over conventional internal combustion engines, has driven the need for more battery charging infrastructure. Furthermore, heavy duty vehicles are also being converted to electric to fill needs such as public transportation via bus fleets as well as cargo delivery via semi-trucks. Such heavy duty vehicles require more energy than personal transportation vehicles and thus require larger battery packs. To charge heavy duty battery packs in the same amount of time as the typical EV, higher power chargers are required.
Energy is distributed through the grid network, and a battery charger is converts the grid power into a regulated output for battery charging. The novel battery charging designs investigated in this thesis are classified differently than traditional designs because they have fewer switching stages to convert the power. The unique approach taken allows these designs to have higher efficiency overall than a traditional battery charger design. The new converter designs are refereed to as the three-level (3L) asymmetrical full bridge (3LAFB)and 3L asymmetrical dual active bridge (3LADAB). The operation of each converter is briefly discussed to help develop context for the hardware and controller designs. The controller design for the 3LAFB topology is developed to explain the control objectives of the 3-port dc-dc converter. Hardware results prototype designs are presented to validate proposed chargers and controller designs. A high power extreme fast charger (XFC) structure is proposed using multiple lower power modules. The high-efficiency design of a single module is presented and hardware results are given
Hydrogen Two-Photon Continuum Emission from the Horseshoe Filament in NGC 1275
Far ultraviolet emission has been detected from a knot of Halpha emission in
the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected
relative to the brightness of the Halpha line in the same spatial region is
very close to that expected from Hydrogen two-photon continuum emission in the
particle heating model of Ferland et al. (2009) if reddening internal to the
filaments is taken into account. We find no need to invoke other sources of far
ultraviolet emission such as hot stars or emission lines from CIV in
intermediate temperature gas to explain these data.Comment: 9 pages, 8 figures. Accepted for publication in MNRA
RELATING FARM AND OPERATOR CHARACTERISTICS TO MULTIPLE GOALS
Farm Management,
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