Estimation of errors in determining corrosion grain sizes by analysis of diffuse light reflection signal

2020 ◽  
Vol 2020 (48) ◽  
pp. 25-34
Author(s):  
I.B. Ivasiv ◽  
Keyword(s):  
Inverse Problem ◽  
Lower Boundary ◽  
Stable Solution ◽  
Light Reflection ◽  
Problem Solution ◽  
Diffuse Light ◽  
Inverse Problem Solution ◽  
Grain Sizes ◽  
Light Diffusion ◽  
Random Location

The approaches to estimation of lower boundary of the inverse problem solution error concerning the sizing the corrosion micro defects inside the submillimeter corrosion spots has been proposed. It is assumed that pointed error depends on random location of the corrosion spots. The method based on comparison of two estimations of light diffusion reflectance sensor’s signal discrepancy. The first estimation is based on the standard deviation for the discrepancy caused by randomly located corrosion spots. The second one is based on corrosion grains’ size deviation. Also, it is found that the discrepancy based on deviations of signal peaks positions provides more stable solution for the corrosion micro defects sizes.

Inverse problem solution for a laser flash studies of a thin layer coatings

2017 ◽  
Vol 27 (3) ◽  
pp. 698-710 ◽  
Author(s):  
Wit Stryczniewicz ◽  
Janusz Zmywaczyk ◽  
Andrzej Jaroslaw Panas
Keyword(s):  
Inverse Problem ◽  
Heat Conduction ◽  
Thin Layer ◽  
Laser Flash ◽  
Problem Solution ◽  
Flake Graphite ◽  
Estimation Technique ◽  
Content Type ◽  
Inverse Problem Solution ◽  
Layer Sample

Purpose The paper aims to discuss the inverse heat conduction methodology in solution of a certain parameter identification problem. The problem itself concerns determination of the thermophysical properties of a thin layer coating by applying the laser flash apparatus. Design/methodology/approach The modelled laser flash diffusivity data from the three-layer sample investigation are used as input for the following parameter estimation procedure. Assuming known middle layer, i.e. substrate properties, the thermal diffusivity (TD) of the side layers’ material is determined. The estimation technique utilises the finite element method for numerical solution of the direct, 2D axisymmetric heat conduction problem. Findings The paper presents methodology developed for a three-layer sample studies and results of the estimation technique testing and evaluation based on simulated data. The multi-parametrical identification procedure results in identification of the out of plane thin layer material diffusivity from the inverse problem solution. Research limitations/implications The presentation itself is limited to numerical simulation data, but it should be underlined that the flake graphite thermophysical parameters have been utilised in numerical tests. Practical implications The developed methodology is planned to be applied in detailed experimental studies of flake graphite. Originality/value In the course of a present study, a methodology of the thin-coating layer TD determination was developed. In spite of the fact that it has been developed for the graphite coating investigation, it was planned to be universal in application to any thin–thick composite structure study.

scholarly journals The Art of Surface Imaging

1991 ◽  
Vol 130 ◽  
pp. 309-320 ◽  
Author(s):  
N.E. Piskunov
Keyword(s):  
Inverse Problem ◽  
High Resolution ◽  
Stellar Atmosphere ◽  
High Resolution Spectroscopy ◽  
Regularization Methods ◽  
Problem Solution ◽  
Surface Imaging ◽  
Late Type ◽  
Inverse Problem Solution ◽  
Additional Constraints

AbstractWe intend to analyze the reliability of surface imaging of stars based on high resolution spectroscopy and the technique of inverse problem solution. Both astrophysical and mathematical aspects including different regularization methods are reviewed. The influence of the different factors on the resulting map is discussed and it is shown that the simultaneous use of different kinds of observational data (spectroscopy, photometry, polarimetry etc.) is very useful in providing additional constraints for the solution. The recent results in the surface imaging of Cp- and late-type stars show the way for further progress: the use of more adequate mathematical description of the stellar atmosphere and the simultaneous consideration of various surface inhomogeneities.

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