Many attempts have been made to automate the process through which vibration signals are analyzed to pinpoint a machine fault. Detailed diagnostic vibration analysis is often performed using portable spectrum analyzers that implement Fast Fourier Transform (FFT) mathematics on the vibration signal. In some instances, only a trained analyst can interpret the vibration data, effectively diagnose ...

A theoretical relation is presented between the seismological Fourier amplitude spectrumand the mean squared value of the elastic response, which is defined by Gaussian distribution. Byshifting a general process to its mean value, spectrum of the mean squared value of the displacementis computed from the Fourier amplitude spectrum and the real part of the relative displacementtransfer function ...

The Fourier analysis of aperiodic ordered time structures related with number eight is considered. Recursion relations for the Fourier amplitudes are obtained for a sequence with discrete spectrum. The continuous spectrum of a different type of sequence is also studied . By increasing the number of points in the time axis dynamic spectra can be obtained and used for sound synthesis.

in this paper we report an eco-friendly route for the synthesis of sliver nanoparticles using agaricus bisporus (white button mushroom) extract. the synthesized silver nanoparticles were confirmed and characterized by uv-visible spectrum of the aqueous solution containing silver ions showed a peak at 420 nm corresponding to the surface plasmon absorbance of silver nanoparticles. transmission el...

Although the spectrum of radially periodic images is often expressed in terms of finite or infinite series of Bessel functions, such expressions do not clearly reveal the exact impulsive structure of the spectrum. An alternative Fourier decomposition of radially periodic images, in terms of circular cosine functions, is presented, and its significant advantages are shown. It is shown that the F...

Consider the indicator function f of a two-dimensional percolation crossing event. In this paper, the Fourier transform of f is studied and sharp bounds are obtained for its lower tail in several situations. Various applications of these bounds are derived. In particular, we show that the set of exceptional times of dynamical critical site percolation on the triangular grid in which the origin ...

Fourier spectrum of the boundary values of functions in the complex Hardy Space H(C+) is characterized for p ∈ (0, 2). First, functions f in the L(R) can be decomposed into a sum g + h, where g and h are the non-tangential boundary limits of function in H(C+) and H(C−) in the sense of L(R), where H(C+) and H(C−) are the Hardy spaces in the upper and lower complex plane C+ and C−, respectively. ...

Warp and weft spacing and its coefficient of variation affect the physical properties of fabrics such as fabric hand, frictional and mechanical properties. In this paper the weft and warp spacing and its coefficient of variation for plain weave is calculated using Fourier transforms. Different methods have been used in this work including autocorrelation function. First, two dimensional power s...

Warp and weft spacing and its coefficient of variation affect the physical properties of fabrics such as fabric hand, frictional and mechanical properties. In this paper the weft and warp spacing and its coefficient of variation for plain weave is calculated using Fourier transforms. Different methods have been used in this work including autocorrelation function. First, two dimensional power s...

The discrete Fourier transform (DFT) maps a nite number of discrete time-domain samples to the same number of discrete Fourier-domain samples. Being practical to compute, it is the primary transform applied to real-world sampled data in digital signal processing. The DFT has special relationships with the discrete-time Fourier transform and the continuous-time Fourier transform that let it be u...