83,943 research outputs found
An evaluation of a SIRA image to determine forest density under conditions of moderate topographical variation
Many studies have shown that radar images have increased classification accuracy over spectral classifications using only LANDSAT Multispectral Band Scanner (MSS) images. It was the objective to determine if a SIRA image taken over Hayfork when used alone or inconjuction with LANDSAT MSS data would increase separation of units not identified by LANSAT spectral mixture models. Areas in the LANDSAT model of varying vegetation density (0 to 50%) that had proven to be accurate by field surveys were compared. It was found in the Hayfork area that SIRA did not increase or help delineation of vegetation or ultramific units over LANDSAT MSS
Are there socioeconomic gradients in stage and grade of breast cancer at diagnosis? Cross sectional analysis of UK cancer registry data
Socioeconomic gradients in uptake of breast cancer screening in the United Kingdom should, intuitively, lead to socioeconomic gradients in disease progression at diagnosis. However, studies have found little evidence of such an effect. Although this could be interpreted as evidence that socioeconomic gradients in uptake of screening do not have clinically important consequences, all of the published studies have used data from before (pre-1988) or during the early stages (1988-95) of implementation of the national breast cancer screening programme. We investigated the relation between socioeconomic position and progression of breast cancer at diagnosis by using recent data from the Northern and Yorkshire Cancer Registry and Information Service (NYCRIS), which is estimated to achieve around 93% ascertainment
The Economic impact of Florida's recreational boating industry in 1985
The recreational boating industry is an important component of Florida's economy. Previous Florida Sea Grant College supported research has documented this economic importance to the state's economy in 1980 (see Milon and Riddle, 1983, and Milon et al. 1983). Since that initial research, the manufacturing, retailing, and service sectors comprising
the industry have continued to grow and prosper as the state's resident and tourist populations increased. This report is an update on the economic significance of the recreational boating industry in Florida since 1980 based on economic indicators of change within the industry. (21pp.
Fracture mechanics of cellular glass
The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses
Tachyon condensation and off-shell gravity/gauge duality
We investigate quasilocal tachyon condensation by using gravity/gauge
duality. In order to cure the IR divergence due to a tachyon, we introduce two
regularization schemes: AdS space and a d=10 Schwarzschild black hole in a
cavity. These provide stable canonical ensembles and thus are good candidates
for the endpoint of tachyon condensation. Introducing the Cardy-Verlinde
formula, we establish the on-shell gravity/gauge duality. We propose that the
stringy geometry resulting from the off-shell tachyon dynamics matches onto the
off-shell AdS black hole, where "off-shell" means non-equilibrium
configuration. The instability induced by condensation of a tachyon behaves
like an off-shell black hole and evolves toward a large stable black hole. The
off-shell free energy and its derivative (-function) are used to show
the off-shell gravity/gauge duality for the process of tachyon condensation.
Further, d=10 Schwarzschild black hole in a cavity is considered for the
Hagedorn transition as a possible explanation of the tachyon condensation.Comment: 28 pages, 13 eps figures, version to appear in IJMP
Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 2
The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacturer of larger helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D, was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR R-49/epoxy skin and graphite/epoxy frames and stringers. The single cure concept is made possible by the utilization of pre-molded foam cores, over which the graphite/epoxy pre-impregnated frame and stringer reinforcements are positioned. Bolted composite channel sections were selected as the optimum joint construction. The applicability of the single cure concept to larger realistic curved airframe sections, and the durability of the composite structure in a realistic spectrum fatigue environment, was described
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