Characterization of fatigued Al lines by means of SThM and XRD: Analysis using fast Fourier transform

2012 ◽  
Vol 52 (4) ◽  
pp. 711-717 ◽  
Author(s):  
R.F. Szeloch ◽  
P. Janus ◽  
J. Serafińczuk ◽  
P.M. Szecówka ◽  
G. Jóźwiak
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Xrd Analysis

scholarly journals Expansions of Functions Based on Rational Orthogonal Basis with Nonnegative Instantaneous Frequencies

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Xiaona Cui ◽  
Suxia Yao
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Fast Algorithm ◽  
Orthogonal Basis ◽  
Basis Functions ◽  
Almost Everywhere ◽  
Integrable Functions ◽  
Instantaneous Frequencies ◽  
Square Integrable Functions

We consider in this paper expansions of functions based on the rational orthogonal basis for the space of square integrable functions. The basis functions have nonnegative instantaneous frequencies so that the expansions make physical sense. We discuss the almost everywhere convergence of the expansions and develop a fast algorithm for computing the coefficients arising in the expansions by combining the characterization of the coefficients with the fast Fourier transform.

Two-Dimensional Fast Fourier Transform and Power Spectrum for Surface Roughness in three Dimensions

1995 ◽  
Vol 209 (5) ◽  
pp. 381-391 ◽  
Author(s):  
W P Dong ◽  
K J Stout
Keyword(s):  
Surface Roughness ◽  
Fourier Transform ◽  
Power Spectrum ◽  
Fast Fourier Transform ◽  
Surface Characterization ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Comprehensive Understanding ◽  
Extract Information

Two-dimensional power spectrums of engineering surfaces contain plenty of information that is important and valuable for surface characterization. However, the characteristics of the two-dimensional spectrums are largely unknown and the algorithm to implement them is not familiar to many engineers or researchers. This paper describes a detailed procedure to implement the two-dimensional fast Fourier transform and power spectrum for surface roughness in three dimensions. Methods used to extract information from the spectrums are introduced. In order to perform two-dimensional spectral analysis and to have a comprehensive understanding of the characteristics of engineering surfaces, an atlas of the two-dimensional spectrums of representative engineering surfaces are presented. The properties of the spectrums are discussed in conjunction with theoretical analysis and visual characterization of the presented spectrums.

CHARACTERIZATION OF INDUSTRIAL WASTEWATER TREATMENT DYNAMICS USING FAST FOURIER TRANSFORM ANALYSIS

1994 ◽  
Vol 30 (2) ◽  
pp. 229-232
Author(s):  
Eloy Bécares ◽  
Antonio J. García-Olivares
Keyword(s):  
Wastewater Treatment ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Industrial Wastewater ◽  
System Complexity ◽  
Industrial Wastewater Treatment ◽  
Fast Fourier Transform Analysis ◽  
And Control ◽  
Final Effluent

Fast Fourier transform analysis has been applied to decompose the variance of some temporal series from an A + B industrial wastewater treatment system, as well as to discriminate which frequencies are basically contributing to parameter variability. The basic oscillations of the effluents, evaluated by means of the total COD, are shown to be mainly dependent on the internal dynamics of the reactors, whose design and control features are the generating forces for the final effluent fluctuations. Owing to the shorter retention time in the first reactor, the output signal was more complex than the input one. Although the second reactor reduces system complexity, it does not have an important effect on the final total COD.

scholarly journals Fast Fourier Transform IR Characterization of Epoxy GY Systems Crosslinked with Aliphatic and Cycloaliphatic EH Polyamine Adducts

Sensors ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 684-696 ◽  
Author(s):  
Goran Nikolic ◽  
Sasa Zlatkovic ◽  
Milorad Cakic ◽  
Suzana Cakic ◽  
Caslav Lacnjevac ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Fourier Transform Ir
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