scholarly journals Frequency Analysis of Transients in Electrochemical Noise of Superalloys Waspaloy and Ultimet

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 702
Author(s):  
Jesús Manuel Jáquez-Muñoz ◽  
Citlalli Gaona-Tiburcio ◽  
Jose Cabral-Miramontes ◽  
Demetrio Nieves-Mendoza ◽  
Erick Maldonado-Bandala ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Electrochemical Noise ◽  
Localized Corrosion ◽  
Polynomial Method ◽  
Widespread Application ◽  
Power Spectral ◽  
Different Temperatures ◽  
Density Analysis ◽  
Power Spectral Density Analysis ◽  
Critical Components

Nickel or Cobalt-based superalloys represent an important class of engineering materials, finding widespread application in critical components within the gas turbine engines used for jet propulsion and electricity generation. This research aimed at the frequency analysis of transients in electrochemical noise of Waspaloy and Ultimet superalloys, immersed in 3.5 wt.% in H2SO4 and NaCl solutions at two different temperatures, 25 and 60 °C. Localized corrosion behavior of superalloys was assessed using the electrochemical noise technique (EN) according to ASTM-G199 standard. Three different statistical methods filtered the EN signal, and the polynomial method was employed to obtain the noise resistance (Rn), the localization index (LI), skew and kurtosis, and the power spectral density analysis (PSD). Results indicate that the current and potential noise transients have a better behavior with better clarity when a polynomial is used to show a localized corrosion kurtosis for both superalloys.

Extraction Feature of Spindle Unbalance of Machine Tool Based on the Wavelet Transform

2011 ◽  
Vol 279 ◽  
pp. 313-317
Author(s):  
Dong Ju Chen ◽  
Jin Wei Fan ◽  
Fei Hu Zhang
Keyword(s):  
Wavelet Transform ◽  
Spectral Density ◽  
Machine Tool ◽  
Power Spectral Density ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Power Spectral ◽  
Density Analysis ◽  
Power Spectral Density Analysis ◽  
Flatness Error

A new method for extracting spectrum feature of spindle unbalance of machine tool is proposed. The flatness error of workpiece surface includes much errors information, and the information contains high frequency signal and low frequency signal. For these errors information, a new identification method of turning errors of workpiece based on the wavelet transform and power spectral density analysis is proposed. According to the focal variation character of wavelet and the energy value of power spectral density analysis, the feature of spindle unbalance from the measured flatness error of workpiece is extracted and identified.

The effect of variable-frequency sounds on plant growth

1973 ◽  
Vol 51 (10) ◽  
pp. 1851-1856 ◽  
Author(s):  
Pearl Weinberger ◽  
U. Graefe
Keyword(s):  
Plant Growth ◽  
Growth And Development ◽  
Random Noise ◽  
Action Spectrum ◽  
Variable Frequency ◽  
General Phenomenon ◽  
Power Spectral ◽  
Density Analysis ◽  
Power Spectral Density Analysis ◽  
Growth Changes

Four tunes and two random noise selections were used to determine whether variable sound frequencies may affect the growth and development of cucumber, corn, and oats. The selections were subjected to a power spectral density analysis. Some growth changes were observed and an indication given that a growth - audio action spectrum may be a widespread general phenomenon.

Angular resolved power spectral density analysis for improving mirror manufacturing

2018 ◽  
Vol 57 (29) ◽  
pp. 8692 ◽  
Author(s):  
Tom Pertermann ◽  
Johannes Hartung ◽  
Matthias Beier ◽  
Marcus Trost ◽  
Sven Schröder ◽  
...  
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Power Spectral ◽  
Density Analysis ◽  
Power Spectral Density Analysis
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