The Evaluation of Noise Spectroscopy Tests

Abstract

Abstract:The paper discusses mathematical tools to evaluate novel noise spectroscopy based analysis and describes, via physical similarity, the mathematical models expressing the quantitative character of the modeled task. Using the Stefan-Boltzmann law, the authors indicate finding the spectral density of the radiated power of a hemisphere, and, for the selected frequency interval and temperature, they compare the simplified models with the expression of noise spectral density according to the Johnson-Nyquist formula or Nyquist's expression of the function of spectral density based on a derivation of Planck's law. The related measurements and evaluations, together with analyses of the noise spectroscopy of periodic resonant structures, are also outlined in the given context.

Modeling and Experimental Verification of Plasma Jet Electromagnetic Signals

“…To select a plasma source conveniently usable in a concrete case, we need to know exactly the attributes of the plasma produced by that source. Thus, a large number of diagnostic methods are required to define the properties of the plasma from various perspectives [1][2][3][4][5][6][7][8][9][10].…”

“…One of the diagnostic approaches is embodied in the analysis of radio frequency (RF) electromagnetic signals, a procedure often utilized in tasks such as the diagnostics of microplasma [5][6][7][8], which generates high-frequency (HF) signals characterized by specific spectra. The actual discharge creates a compound signal [5][6][7][8] capable of being theoretically described and modeled [11][12][13][14][15][16][17][18][19][20]. To verify the functionality of the method, we employed an atmospheric-pressure plasma source, namely, a plasma pencil (Figure 1) similar to that modeled in report [11].…”

“…A set of selected plasma parameters that are significant in terms of the electromagnetic field model created and discussed herein is presented in Table 1. The functionality of the proposed methodology and the actual models of the field [22][23][24][25][26][27][28][29][30] was verified by measuring the electromagnetic field irradiated by the plasma jet, with the plasma located close to the jet orifice; the actual measurement was performed using a suitably designed dipole antenna [5][6][7][8] linked to a frequency analyzer. Table 1.…”

Detection of seepages in flood embankments using the ElasticNET method

“…This method of imaging consists in the fact that the conductivity distribution of the tested object is estimated on the basis of measurements of electrical voltages and electrode potentials on the surface of their contact with the tested object. In order to obtain quantitative data on changes in the conductivity inside an object, it is more effective to apply a non-linear model in differential imaging [1,[6][7][8][9][10][11][12]14,[26][27][28][29][30][31]. In Fig.…”

Measuring of noise emitted by moving vehicles

“…Measurements were performed in the frequency range from 3 Hz to 20 kHz, and in 1/3 octave bands. The maximum sound level, LAFmax, and the equivalent sound level, LAeq, were recorded, and the results were adjusted by means of correction curve A [10,11]. …”