12,035 research outputs found
GALEX Observations of Diffuse UV Radiation at High Spatial Resolution from the Sandage Nebulosity
Using the GALEX ultraviolet imagers we have observed a region of nebulosity
first identified as starlight scattered by interstellar dust by Sandage (1976).
Apart from airglow and zodiacal emission, we have found a diffuse UV background
of between 500 and 800 \phunit in both the \galex FUV (1350 -- 1750 \AA) and
NUV (1750 -- 2850 \AA). Of this emission, up to 250 \phunit is due to \htwo
fluorescent emission in the FUV band; the remainder is consistent with
scattering from interstellar dust. We have estimated the optical constants to
be in the FUV and in the NUV, implying
highly forward scattering grains, plus an extragalactic contribution of as much
as 150 \phunit. These are the highest spatial resolution observations of the
diffuse UV background to date and show an intrinsic scatter beyond that
expected from instrumental noise alone. Further modeling is required to
understand the nature of this scatter and its implications for the ISM.Comment: Total 20 pages, Figures 9, Accepted for publication in Astrophysical
Journa
The WINCOF-I code: Detailed description
The performance of an axial-flow fan-compressor unit is basically unsteady when there is ingestion of water along with the gas phase. The gas phase is a mixture of air and water vapor in the case of a bypass fan engine that provides thrust power to an aircraft. The liquid water may be in the form of droplets and film at entry to the fan. The unsteadiness is then associated with the relative motion between the gas phase and water, at entry and within the machine, while the water undergoes impact on material surfaces, centrifuging, heat and mass transfer processes, and reingestion in blade wakes, following peal off from blade surfaces. The unsteadiness may be caused by changes in atmospheric conditions and at entry into and exit from rain storms while the aircraft is in flight. In a multi-stage machine, with an uneven distribution of blade tip clearance, the combined effect of various processes in the presence of steady or time-dependent ingestion is such as to make the performance of a fan and a compressor unit time-dependent from the start of ingestion up to a short time following termination of ingestion. The original WINCOF code was developed without accounting for the relative motion between gas and liquid phases in the ingested fluid. A modification of the WINCOF code was developed and named WINCOF-1. The WINCOF-1 code can provide the transient performance of a fan-compressor unit under a variety of input conditions
Asymptotic analysis and spectrum of three anyons
The spectrum of anyons confined in harmonic oscillator potential shows both
linear and nonlinear dependence on the statistical parameter. While the
existence of exact linear solutions have been shown analytically, the nonlinear
dependence has been arrived at by numerical and/or perturbative methods. We
develop a method which shows the possibility of nonlinearly interpolating
spectrum. To be specific we analyse the eigenvalue equation in various
asymptotic regions for the three anyon problem.Comment: 28 pages, LaTeX, 2 Figure
WINCOF-I code for prediction of fan compressor unit with water ingestion
The PURDUE-WINCOF code, which provides a numerical method of obtaining the performance of a fan-compressor unit of a jet engine with water ingestion into the inlet, was modified to take into account: (1) the scoop factor, (2) the time required for the setting-in of a quasi-steady distribution of water, and (3) the heat and mass transfer processes over the time calculated under 2. The modified code, named WINCOF-I was utilized to obtain the performance of a fan-compressor unit of a generic jet engine. The results illustrate the manner in which quasi-equilibrium conditions become established in the machine and the redistribution of ingested water in various stages in the form of a film out of the casing wall, droplets across the span, and vapor due to mass transfer
Work capacity and surgical output for cataract in the national capital region of Delhi and neighbouring districts of north India.
OBJECTIVES: To ascertain time taken for cataract surgery by ophthalmologists in the National Capital Region of Delhi and neighbouring districts, to determine what work output is feasible with the available ophthalmologists. METHODS: The time-motion study was conducted during January to June 2006 in the National Capital Region of Delhi and neighbouring districts in North India. Data was collected by observing all activities from entry of a patient into the operating theatre to exit. A total of 156 cataract surgeries performed by 45 ophthalmologists in 38 hospitals were observed. A stop watch was used to record activity time, rounded off to the nearest 10 seconds. Case duration, surgical and clinical times were calculated. RESULTS: Ninety percent ophthalmologists completed surgery in 41.3 minutes. The 10th and 90th percentile for case duration time was 15.5 and 78.4 minutes respectively. Median surgical time was lowest for ophthalmologists working in the NGO sector (10 minutes), compared to the government (23.5 minutes), and private sector (17.3 minutes). Cataract surgical output can be increased in the country if operation theatre time is utilized optimally
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