Calibration specimen

Ability to perform chemical analysis of a sample by using colour scale map of standard (calibrated) specimen Analysis can be performed outdoors... 

Fig. 2.32 Left Schematic of calibration specimen Right Example of experimental data measured with a Si3N4 tip on both sloped and flat surfaces (a) topography image (vertical scale from black to white 800 nm), (b) cross section of topography (vertical scale 800 nm), (c) difference friction image (trace - retrace, vertical scale 0.5 V), (d) off-set of the friction loops (trace + retrace, vertical scale 0.5 V) and (e) friction loop corresponding to cross section shown in panel (b) (the off-sets for sloped and flat surface, As and /1r, respectively, have been marked). Reproduced with permission from reference [18]. Copyright 2006. American Chemical Society...

For measurements in liquid, an additional correction factor that corrects the effect of refraction must be considered. By multiplication with the factor naiiMiquid (n refractive index) one can conveniently rescale the values of lateral photodiode sensitivity obtained in air (6LAlr) employing, e.g., the improved wedge calibration method using a universal calibration specimen, to obtain the correct value for... 

ISO 5436 1985 Calibration specimens — Stylus instruments — Types, calibration and use of specimens. 

Sterilized parts of the polymer (or even calibrated specimens) are placed on a sterile agar medium inoculated with known strains of bacteria and/or fungi. It is also possible to simply put the plastic polymers in contact with agricultural soil or compost. The development of bacteria and/or fungi is then observed as well as the... 

The last two techniques are absolute methods since they do not require the use of reference or calibration specimen. However they are relatively expensive and time-consuming and difficult to adapt to rapid testing. 

Multiple linear regression (MLR) involves finding regression equations in the form Cl = boi + b Ai + b2iA2 + + In order to carry out MLR the number of calibration specimens must be greater than the number of predictors. This is true for the data in Table 8.4 where there are 10 specimens and six predictors. 

The majority of all work carried out to date makes use of arrival time analysis, and subsequently a wave velocity value for thickness measurement and for defect location. The wave velocity in a composite material is difficult to use precisely because of the anisotropic characteristics of a composite material. A typical wave or phase velocity profile in polar coordinates is illustrated in Figure 8, showing the nonspherical nature of the wave velocity distribution. The wave velocity distribution can even be more complex for a realistic composite material structure. Despite a possible weakness in the understanding of basic physics and wave propagation in a composite material, thickness measurement can still be carried out by using carefully selected calibration specimens and procedures. Calibration of a test instrument can therefore be carried out for subsequent thickness measurement and defect location analysis in a structure. 

Smaller temperature calibration specimens (about 100 pm thick) should be used. 

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