Comments on the Article “An Electrochemical Impedance Measurement Technique Employing Fourier Transform” by J.-S. Yoo and S.-M. Park

2001 ◽  
Vol 73 (16) ◽  
pp. 4059-4059 ◽  
Author(s):  
Andrzej Lasia
Keyword(s):  
Fourier Transform ◽  
Measurement Technique ◽  
Electrochemical Impedance ◽  
Impedance Measurement

An Eigenvalue Based Acoustic Impedance Measurement Technique

1991 ◽  
Vol 113 (2) ◽  
pp. 250-254 ◽  
Author(s):  
A. J. Hull ◽  
C. J. Radcliffe
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Frequency Response ◽  
Measurement Technique ◽  
Acoustic Impedance ◽  
Laboratory Tests ◽  
Impedance Measurement ◽  
Wave Pattern ◽  
Impedance Tube ◽  
One Dimensional

A method is developed for measuring acoustic impedance. The method employs a one-dimensional tube or duct with excitation at one end and an unknown acoustic impedance at the termination end. Microphones placed in the tube are then employed to measure the frequency response of the system from which acoustic impedance of the end is calculated. This method uses fixed instrumentation and takes advantage of modern Fast Fourier Transform analyzers. Conventional impedance tube methods have errors resulting from movement of microphones to locate the maxima and minima of the wave pattern in the impedance tube or require phase matched microphones with specific microphone spacing. This technique avoids these problems by calculating the acoustic impedance from measured duct eigenvalues. Laboratory tests of the method are presented to demonstrate its accuracy.

scholarly journals Impact of Relaxation Time on Electrochemical Impedance Spectroscopy Characterization of the Most Common Lithium Battery Technologies—Experimental Study and Chemistry-Neutral Modeling

2021 ◽  
Vol 12 (2) ◽  
pp. 77
Author(s):  
Md Sazzad Hosen ◽  
Rahul Gopalakrishnan ◽  
Theodoros Kalogiannis ◽  
Joris Jaguemont ◽  
Joeri Van Mierlo ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Impedance Measurement ◽  
Nonlinear Behavior ◽  
Lithium Ion ◽  
Health Condition ◽  
Battery Cell ◽  
Rest Time

In electrified vehicle applications, understanding the battery characteristics is of great importance as it is the state-of-art principal energy source. The key battery parameters can be identified by one of the robust and nondestructive characterization techniques, such as electrochemical impedance spectroscopy (EIS). However, relaxing the battery cell before performing the EIS method is crucial for the characterization results to be standardized. In this study, the three most common and commercially available lithium-ion technologies (NMC/graphite, LFP/graphite, NCA/LTO) are investigated at 15–45 °C temperature, in the range of 20–80% state of charge (SoC) and in fresh and aged state of health (SoH) conditions. The analysis shows that the duration of the relaxation time before impedance measurement has an impact on the battery’s nonlinear behavior. A rest time of 2 h can be proposed, irrespective of battery health condition, considering neutral technology-based impedance measurement. An impedance growth in ohmic and charge transfer characteristics was found, due to aging, and the effect of rest periods was also analyzed from an electrochemical standpoint. This experimental data was fitted to develop an empirical model, which can predict the nonlinear dynamics of lithium technologies with a 4–8% relative error for longer rest time.

Corrosion Inhibition of Mild Steel by Electrodeposited Poly(M-Aminophenol) Coating

2021 ◽  
Vol 317 ◽  
pp. 498-505
Author(s):  
Sabrina M. Yahaya ◽  
Mohamad Kamal Harun ◽  
Ismaliza Ismail ◽  
Rosmamuhamadani Ramli
Keyword(s):  
Mild Steel ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Impedance Measurement ◽  
Barrier Properties ◽  
Electrical Circuit ◽  
Significant Drop ◽  
Mild Steel Surface ◽  
Barrier Resistance ◽  
And Performance

In this study, poly(m-aminophenol) (PMAP) coating was electrochemically synthesized by cyclic voltammetry (CV) on mild steel surface to investigate the effects of its barrier protection within the scope of its electrochemical impedance towards further oxidation of the mild steel substrates. The developed PMAP coating were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The barrier resistance ability of PMAP coating towards corrosion of mild steel was determined in 0.5 M aqueous sodium chloride solution (NaCl) at various immersion times by the electrochemical impedance spectroscopy (EIS). The barrier properties were interpreted through impedance measurement using Nyquist and Bode plots. Equivalent electrical circuit models derived from the plots were employed to describe the coating barrier behaviour and performance. Data obtained showed that, the oxidation peak of PMAP coating were observed at potential +1.0 V (Ag/AgCl). The micrograph of FESEM indicates the formation of a dense and continous PMAP coatings. In FTIR analyses, the presence of peak around 1082 cm-1 ascribed to C–O–C etheric linkage which supported the formation of electro polymerized PMAP coating on mild steel surface. EIS measurement revealed that, PMAP coatings experienced a significant drop in total impedance values with time followed by the development of an electrochemical reactions on coating/metal interface, which indicates the gradual degradation of the barrier resistance ability of the PMAP coatings.

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