Swept-Frequency Transfer Function and Pulse Testing of a Small Scale Graphite Test Article for Comparison With Lightning Indirect Effects Analysis

2001 ◽  
Author(s):  
Donald Dabelstein ◽  
Barbara Melander
Keyword(s):  
Transfer Function ◽  
Indirect Effects ◽  
Small Scale ◽  
Test Article ◽  
Pulse Testing ◽  
Frequency Transfer

scholarly journals Speckle Observations of Solar Granulation

1994 ◽  
Vol 158 ◽  
pp. 398-400 ◽  
Author(s):  
C.R. de Boer ◽  
F. Kneer
Keyword(s):  
Transfer Function ◽  
Broad Band ◽  
Active Regions ◽  
Spectral Ratio ◽  
Speckle Interferometry ◽  
Frame Rate ◽  
Small Scale ◽  
Fourier Plane ◽  
Pass Filter ◽  
Low Pass Filter

Image reconstruction by means of speckle interferometry was successfully used to restore the intensity distribution of solar features and to investigate the morphology and dynamics of small-scale structures in active regions of the Sun. The observations were obtained with the Vacuum Tower Telescope (D = 70 cm, f = 46 m) at Observatorio del Teide, Tenerife, on May 17 and 20, 1991, from a plage region close to a sunspot near disc centre. Sequences of bursts consisting of 100 exposures were recorded with a broad-band filter centred at 550 nm (FWHM ≈ 10 nm, diffraction limit 0.2 arcsec). The pickup unit was a video CCD – system with an exposure time of 4 ms and a frame rate of three pictures per second. A description of the observing procedure and of the data handling can be found in de Boer et al. (1992). To obtain the complex Fourier phases speckle masking (Lohmann et al. 1983) was used. The speckle transfer function of the atmosphere was calculated indirectly using Korff's equation (1973). The Fried parameter r0 was estimated with the spectral ratio technique (von der Lühe 1984). This parameter was sometimes as large as 14 cm. With this the theoretical speckle transfer function could be determined for calculating the corrected Fourier amplitudes of the reconstruction. A new low pass filter, based on the reliability of each individual value in the Fourier plane, was applied to the amplitudes to suppress noise at high wavenumbers.

Phase measurement of nonuniform phase-shifted interferograms using the frequency transfer function

2019 ◽  
Vol 58 (15) ◽  
pp. 4157 ◽  
Author(s):  
Ivan Choque ◽  
Manuel Servin ◽  
Moises Padilla ◽  
Miguel Asmad ◽  
Sotero Ordones
Keyword(s):  
Transfer Function ◽  
Phase Measurement ◽  
Frequency Transfer

Frequency Transfer Function From Fluid Temperature Fluctuations to Stress Intensity Factors

2003 ◽  
Author(s):  
Naoto Kasahara ◽  
Masanori Ando ◽  
Ihciro Furuhashi ◽  
Chen Fuquan ◽  
Hideki Takasho
Keyword(s):  
Stress Intensity ◽  
Transfer Function ◽  
Stress Intensity Factors ◽  
Temperature Fluctuation ◽  
Fatigue Cracks ◽  
Temperature Fluctuations ◽  
Fluid Temperature ◽  
Intensity Factors ◽  
Rational Analysis ◽  
Frequency Transfer

Temperature fluctuation from incomplete fluid mixing can induce fatigue cracks on structures of nuclear components, which should be prevented. For rational analysis of this phenomenon, the authors have developed a frequency transfer function that translates fluid temperature fluctuation to stress intensity factors. This function is formulated by a product of the effective heat transfer and the stress intensity factor functions, and enables us to quickly calculate stresses intensity factors induced by fluid temperature fluctuations. Furthermore, it can evaluate sensitivities of stress intensity factors to frequencies of temperature fluctuation, Biot number and constraint conditions of structures. Applicability of this function was verified through comparison with stress intensity factors calculated by the finite element method.

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