Extraneous Radiation On Space Borne Infrared Experiments

1988 ◽  
Author(s):  
Stephan D. Price
Keyword(s):  
Extraneous Radiation

A device for distinguishing weak spectral lines against a background of extraneous radiation

1974 ◽  
Vol 21 (2) ◽  
pp. 1125-1128 ◽  
Author(s):  
D. A. Katskov ◽  
L. P. Kruglikova ◽  
B. V. L'vov ◽  
N. A. Orlov ◽  
L. K. Polzik
Keyword(s):  
Spectral Lines ◽  
Extraneous Radiation

scholarly journals The Effects of Combustor Cooling Features on Nozzle Guide Vane Film Cooling Experiments

2018 ◽  
Author(s):  
Nicholas E. Holgate ◽  
Peter T. Ireland ◽  
Eduardo Romero
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Stagnation Region ◽  
Airfoil Surface ◽  
Cooling Performance ◽  
Nozzle Guide Vane ◽  
Effectiveness Measurement ◽  
Extraneous Radiation ◽  
Nozzle Guide ◽  
Endwall Film Cooling

Recent advances in experimental methods have allowed researchers to study nozzle guide vane film cooling in the presence of combustor dilution ports and endwall films. The dilution injection creates nonuniformities in temperature, velocity, and turbulence, and an understanding of the vane film cooling performance is complicated by competing influences. In this study, dilution port temperature profiles have been measured in the absence of vane film cooling and compared to film effectiveness measurements in the presence of both films and dilution, illustrating the effects of the dilution port turbulence on film cooling performance. It is found that dilution port injection can create significant effectiveness benefits at the difficult-to-cool vane stagnation region, due to the more turbulent hot mainstream enhancing the mixing of film coolant jets that have left the airfoil surface. Also explored are the implications of endwall film cooling for infrared vane surface temperature measurements. The reduced endwall temperatures reduce the thermal emissions from this surface, so reducing the amount of extraneous radiation reflected from the vane surface where measurements are being made. The results of a detailed calibration show that the maximum local film effectiveness measurement error could be up to 0.05 if this effect were to go unaccounted for.

scholarly journals An Optical Design for an Antarctic 2 m Telescope with a Near IR Imager

2002 ◽  
Vol 19 (3) ◽  
pp. 301-305 ◽  
Author(s):  
P. R. Gillingham
Keyword(s):  
Optical Design ◽  
Detector Array ◽  
Optical Performance ◽  
Primary Mirror ◽  
Low Level ◽  
Near Ir ◽  
Field Curvature ◽  
Ir Imager ◽  
Extraneous Radiation

AbstractA study has been made of the optical performance to be expected from an Antarctic Ritchey Chrétien telescope with a 2 m diameter primary mirror imaging directly onto a detector array in the K and L infrared windows. Near diffraction limited performance is provided across a flat 30 arcmin diameter field by compensating the astigmatism and field curvature with a meniscus lens which also serves as the Dewar window. With baffling inside and Narcissus mirrors outside the Dewar, extraneous radiation can be kept to a low level.

A quantitative investigation of thin specimen X-ray spectra in the TEM

1978 ◽  
Vol 36 (1) ◽  
pp. 550-551
Author(s):  
B.W. Robertson ◽  
J.N. Chapman ◽  
W.A.P. Nicholson ◽  
R.P. Ferrier
Keyword(s):  
Electron Microscope ◽  
Electron Probe ◽  
X Rays ◽  
Quantitative Investigation ◽  
Solid Materials ◽  
Thin Specimen ◽  
X Ray ◽  
Transmission Electron ◽  
Extraneous Radiation ◽  
The Continuum

In electron probe x-ray microanalysis, the observed x-ray spectra are degraded by the presence of both characteristic and bremsstrahlung x-rays from the regions of the specimen which are not under analysis and from the solid materials near the specimen. These x-rays are generated by electrons scattered from the probe by the specimen and by stray electrons originally outside the probe. The extraneous bremsstrahlung x-rays form a component of the observed continuum which is only indirectly dependent on the nature of the specimen. This effect is particularly undesirable in the analysis of thin biological specimens in the transmission electron microscope since the continuum level is commonly used in quantitative analysis as a measure of specimen mass thickness. Experiments have therefore been performed to investigate the magnitude of the extraneous radiation and to evaluate the success of attempts to reduce it. These have been detailed elsewhere (Nicholson et al. 1977).

The Effects of Combustor Cooling Features on Nozzle Guide Vane Film Cooling Experiments

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Nicholas E. Holgate ◽  
Peter T. Ireland ◽  
Eduardo Romero
Keyword(s):  
Film Cooling ◽  
Guide Vane ◽  
Stagnation Region ◽  
Airfoil Surface ◽  
Cooling Performance ◽  
Nozzle Guide Vane ◽  
Effectiveness Measurement ◽  
Extraneous Radiation ◽  
Nozzle Guide ◽  
Endwall Film Cooling

Abstract Recent advances in experimental methods have allowed researchers to study nozzle guide vane (NGV) film cooling in the presence of combustor dilution ports and endwall films. The dilution injection creates nonuniformities in temperature, velocity, and turbulence, and an understanding of the vane film cooling performance is complicated by competing influences. In this study, dilution port temperature profiles have been measured in the absence of vane film cooling and compared to film effectiveness measurements in the presence of both films and dilution, illustrating the effects of the dilution port turbulence on film cooling performance. It is found that dilution port injection can create significant effectiveness benefits at the difficult-to-cool vane stagnation region due to the more turbulent hot mainstream enhancing the mixing of film coolant jets that have left the airfoil surface. Also explored are the implications of endwall film cooling for infrared (IR) vane surface temperature measurements. The reduced endwall temperatures reduce the thermal emissions from this surface, so reducing the amount of extraneous radiation reflected from the vane surface where measurements are being made. The results of a detailed calibration show that the maximum local film effectiveness measurement error could be up to 0.05 if this effect were to go unaccounted for.

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