scholarly journals Optimisation of the setup of LPR and EIS measurements for the onsite, non-invasive study of metallic artefacts

2020 ◽  
Vol 24 (11-12) ◽  
pp. 3257-3267
Author(s):  
Chiara Petiti ◽  
Davide Gulotta ◽  
Bruna Mariani ◽  
Lucia Toniolo ◽  
Sara Goidanich
2019 ◽  
Vol 8 (1) ◽  
pp. 84-96 ◽  
Author(s):  
B. Tsai ◽  
H. Xue ◽  
E. Birgersson ◽  
S. Ollmar ◽  
U. Birgersson

Abstract A mechanistic mathematical model for electrical impedance spectroscopy (EIS) measurements of human skin is analyzed, leading to a reduced model and approximate solutions. In essence, the model considers a complex-valued Laplace equation in the frequency domain for the alternating current from a circular EIS probe passing through the layers – stratum corneum, viable skin and adipose tissue – of human skin in the frequency range 1 kHz – 1 MHz. The reduced model, which only needs to be solved numerically for the viable skin with modified boundary conditions, is verified with the full set of equations (non-reduced model): good agreement is found with a maximum relative error of less than 3%. A Hankel transform of the reduced model allows for approximate solutions of not only the measured impedance but also the point-wise potential distribution in the skin. In addition, the dimensionless numbers governing the EIS are elucidated and discussed.


Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 901
Author(s):  
Xinyue Jiang ◽  
Yuqun Xie ◽  
Duanji Wan ◽  
Fuping Zheng ◽  
Jun Wang

A non-invasive real-time detection technique for phthalates in Chinese liquor is proposed in this paper. This method is based on the measurement of Faradaic impedance in the presence of a redox probe, [Fe(CN)6]3−/4−, upon the absorption of phthalates to the graphene electrode surface. This absorption activity is according to the π–π stacking interactions between phthalates and the graphene working electrode which allows direct sampling and analyte preconcentration. The absorption of phthalates retards the interfacial electron-transfer kinetics and increases the charge-transfer resistance (Rct). Numerical values of Rct were extracted from a simulation of electrochemical impedance spectroscopy (EIS) spectra with the corresponding equivalent circuit. Cathodic polarization was employed prior to EIS measurements to effectively eliminate the metal ion interference. The results yielded a detection limit of 0.024 ng/L for diethyl phthalate (DEP) with a linear range from 2.22 ng to 1.11 µg. These results indicate a possibility of developing a household sensor for phthalate determination in Chinese liquor.


2018 ◽  
Vol 9 (1) ◽  
pp. 31-38 ◽  
Author(s):  
B. Tsai ◽  
E. Birgersson ◽  
U. Birgersson

Abstract An approximate semi-analytical solution based on a Hankel transform of a mechanistic model for electrical impedance spectroscopy (EIS) is derived for a non-invasive axisymmetric concentric probe with m electrodes measuring the response of n layers of human skin. We validate the semi-analytical solution for the case when the skin is treated as a three-layer entity - (i) stratum corneum, (ii) viable skin comprising living epidermis and dermis and (iii) adipose tissue – on the volar forearm in the frequency range 1 kHz to 1 MHz with experimental EIS measurements of 120 young subjects. Overall, we find good agreement for both the mean magnitude and phase of the impedance as well as the natural variability between subjects. Finally, the semi-analytical solution is verified with the full set of equations solved numerically: Good agreement is found for the point-wise potential distribution in the three skin layers.


Author(s):  
H.W. Deckman ◽  
B.F. Flannery ◽  
J.H. Dunsmuir ◽  
K.D' Amico

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.


2001 ◽  
Vol 120 (5) ◽  
pp. A266-A266
Author(s):  
R BUTLER ◽  
B ZACHARAKIS ◽  
D MOORE ◽  
K CRAWFORD ◽  
G DAVIDSON ◽  
...  

2001 ◽  
Vol 120 (5) ◽  
pp. A491-A491 ◽  
Author(s):  
A LEODOLTER ◽  
D VAIRA ◽  
F BAZZOLL ◽  
A HIRSCHL ◽  
F MEGRAUD ◽  
...  
Keyword(s):  

2020 ◽  
Vol 158 (6) ◽  
pp. S-1249
Author(s):  
Yuri Hanada ◽  
Juan Reyes Genere ◽  
Bryan Linn ◽  
Tiffany Mangels-Dick ◽  
Kenneth K. Wang

2007 ◽  
Vol 177 (4S) ◽  
pp. 430-430
Author(s):  
Ram Ganapathi ◽  
Troy R. Gianduzzo ◽  
Arul Mahadevan ◽  
Monish Aron ◽  
Lee E. Ponsky ◽  
...  

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