Study on the measurement speed and signal to noise ratio of multi tone burst wave for high speed non-contact acoustic inspection method

2016 ◽  
Vol 140 (4) ◽  
pp. 3212-3212
Author(s):  
Nobuaki Kosuge ◽  
Tsuneyosi Sugimoto ◽  
Kazuko Sugimoto ◽  
Chitose Kuroda ◽  
Noriyuki Utagawa
1995 ◽  
Vol 235 (5-6) ◽  
pp. 508-510
Author(s):  
Geng-Ying Li ◽  
Xue-Cheng Xu ◽  
Yi Liu ◽  
Xue-Wen Wu

2012 ◽  
Vol 83 (8) ◽  
pp. 083710 ◽  
Author(s):  
O. D. Payton ◽  
L. Picco ◽  
M. J. Miles ◽  
M. E. Homer ◽  
A. R. Champneys

2006 ◽  
Vol 14 (3) ◽  
pp. 243-250 ◽  
Author(s):  
Nicolò Cavina ◽  
Giovanni Cipolla ◽  
Francesco Marcigliano ◽  
Davide Moro ◽  
Luca Poggio

2021 ◽  
Author(s):  
Dmitry Rybashlykov ◽  
Jaclyn Brennan ◽  
Zexu Lin ◽  
Igor R. Efimov ◽  
Roman Syunyaev

Fluorescent imaging with voltage- or calcium-sensitive dyes, i.e. optical mapping, is one of the indispensable modern techniques to study cardiac electrophysiology, unsurpassed by temporal and spatial resolution. High-speed CMOS cameras capable of optical registration of action potential propagation are in general very costly. We present a complete solution priced below US$1,000 (including camera and lens) at the moment of publication with an open-source image acquisition and processing software. We demonstrate that the iDS UI-3130CP rev.2 camera we used in this study is capable of 200x200 977 frames per second (FPS) action potential recordings from rodent hearts. The signal-to-noise-ratio of a conditioned signal was 16 ± 10 for rodent hearts. A comparison with a specialized MiCAM Ultimate-L camera has shown that signal-to-noise ratio (SNR) is sufficient for accurate measurements of AP waveform, conduction velocity (± 0.04 m/s) and action potential duration (± 7ms) in mouse and rat hearts. We measured the action potential prolongation during 4-aminopyridine administration in mouse heart, showing that proposed system signal quality is adequate for drug studies.


Author(s):  
Douglas S. Shukert

Remote Induced Current Potential Drop (RICPD) is a nondestructive inspection method for finding cracks within stainless steel pipes. One problem with RICPD inspection is that the RICPD signal is very weak and is therefore, susceptible to being overshadowed by noise. Especially when trying to detect shallow cracks, the RICPD signal-to-noise ratio can be quite small, making signals from cracks indistinguishable from random signal noise. By using a mathematical filtering technique known as “normalized correlation” RICPD signals can be processed to extract meaningful data from noisy signals. Normalized correlation uses the signal waveform from a known crack as a model and compares that model waveform to every point of the RICPD test signal. All points that produce a match to the model are suspected cracks. Since normalized correlation does not depend on the magnitude of the signal or on the signal-to-noise ratio, even small cracks that produce nearly imperceptible signals can be detected. To successfully apply the normalized correlation algorithm, all that is needed is a model of the signal waveform from a known crack. The normalized correlation filtering technique has been successfully applied to 40mm thick blocks of stainless steel in the laboratory to detect underside man-made slits as shallow as 10mm.


2016 ◽  
Vol 140 (4) ◽  
pp. 3212-3213
Author(s):  
Tsuneyoshi Sugimoto ◽  
Kazuko Sugimoto ◽  
Nobuaki Kosuge ◽  
Chitose Kuroda ◽  
Noriyuki Utagawa

Author(s):  
S. J. Steinberg ◽  
R. King ◽  
C. Tiedemann ◽  
D. Peitsch

Active flow control is a powerful option to ensure secure operation and enhancement of the performance of axial compressors. To achieve these goals for aerodynamically highly loaded compressor blade profiles even under disturbed conditions, the magnitude of the actuation needs to be adjusted by a closed-loop controller. To this end, sensors must be placed at some meaningful positions at the surface of the blades giving information about the flow situation inside the passages. The sensor information can then lead to surrogate control variables to close the loop. Often, good sensor positions are unknown initially and therefore chosen naively or experience-driven. To obtain more informative surrogate control variables, a different approach is chosen here. Starting with a highly instrumented blade inside a linear stator cascade, featuring 16 pressure gauges in an area which is suspected to lead to high information content with respect to detrimental flow separations at the sidewalls, a Principal Component Analysis is done. The principal components provide valuable information about where and how intensively the flow is influenced by the actuation. This is validated by comparison with the results of oil flow visualizations and wake measurements. The goal is to find a linear combination of as few sensors as possible to provide a meaningful input for the closed-loop controller. As experiments are conducted up to Ma = 0.8, the signal-to-noise ratio becomes a critical issue. For this reason, specifically weighted data are introduced here. A linear combination of sensor data is obtained, describing the main effects of the actuation with an almost linear mapping. For the given set of sensors, that linear combination achieves a maximum signal-to-noise ratio, which makes it well suited as a control variable. The practical usefulness of the control variable within a robust ℋ∞-flow controller is verified in experiments in a high speed stator cascade.


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