Questioning the aloe vera plant and apple memristors

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Publicado en línea: 26 dic 2019

Páginas: 83 - 89

Recibido: 04 dic 2019

DOI: https://doi.org/10.2478/joeb-2019-0012

Palabras clave
Bioimpedance, non-linear electrical properties, memristor, electrodes, cyclic voltammetry

© 2019 Pabst., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Methods, a) Voltage stimuli that were used in the experiment. The voltages used on the apple juice (manually obtained from one apple) are listed in the table. The measurements on the apple juice from concentrate were only done with sinusoidal voltages with amplitudes of 2.5 V and 4 V. b) Schematic of the measurement instrumentation. The recordings under the measurement electrodes M1, and M2 are monopolar and were done simultaneously, which was enabled by a three electrode setup (see [8]) with “CC” as the current carrying electrode and “Ref” as the reference electrode. c) Electrode placement on the whole apple (left), on the apple piece (middle), the apple liquid (right), apple juice from concentrate (bottom left), aloe vera leave (bottom middle) and the aloe vera liquid (bottom right).

Voltage current plots recorded from the aloe vera plants, always shown for the second period of each measurement. The dark blue plots represent the results from recordings with the silver/silver chloride electrode and the light blue plots from the recordings with the medical stainless steel needle electrode. a) Results from one leaf of one aloe vera plants (A) shown for applied sinusoidal voltages with amplitudes of 5 V and 2.5 V and frequency equal to 0.005 Hz. The recordings obtained by the silver/silver chloride electrode are slightly non-linear. Pinched hysteresis loops with small loop area and pinched point position in the first quadrant were obtained. b) Results from the liquid of one leaf of one aloe vera plant shown for applied sinusoidal voltages with amplitudes of 4 V and 2.5 V and a frequency of 0.005 Hz.

Voltage current plots recorded from the apples, always shown for the second period of each measurement. The dark blue plots represent the results from recordings with the silver/silver chloride electrode and the light blue plots from the recordings with the stainless steel needle electrode. All shown results were obtained by applying sinusoidal voltages with a frequency of 0.005 Hz and different amplitudes. a) Results from the measurements on one whole apple (A) (used amplitudes were 4 V and 2 V). Similar results were obtained from two other apples (B and C). The recordings from the apple D (see Fig. S2) were slightly more linear. b) Recordings from the apple juice that was manually extracted (used amplitudes were 4 V and 2.5 V). The cutoff in the plot of the recording with the stainless steel needle at 4 V amplitude is due to saturation of the transimpedance amplifier. c) Recordings from the apple juice from concentrate (used amplitudes were 4 V and 2.5 V).

Additional voltage current plots recorded from the aloe vera plants, always shown for the second period of each measurement. The dark blue plots represent the results from recordings with the silver/silver chloride electrode and the light blue plots from the recordings with the stainless steel needle electrode. a) Results from the leaf of one aloe vera plant (A) shown for applied sinusoidal voltage with an amplitude of 5 V and frequency equal to 0.05 Hz and frequency equal to 0.5 Hz and triangular voltage with 5 V amplitude and frequency of 0.005Hz. b) Results from the extracted liquid of one aloe vera leaf shown for applied sinusoidal voltage with an amplitude of 4 V and frequency of 0.05 Hz and 0.5 Hz and triangular voltage with an amplitude of 4 V and frequency of 0.005 Hz. c) Results from the leaf of another aloe vera plant (B) shown for sinusoidal voltage with an amplitude of 5 V and frequency f = 0.005 Hz.

Additional voltage current plots recorded from the apples, always shown for the second period of each measurement. The dark blue plots represent the results from recordings with the silver/silver chloride electrode and the light blue plots from the recordings with the stainless steel needle electrode. a) Results from the manual extracted apple juice shown for applied sinusoidal voltage with an amplitude of 2.5 V and frequency equal to 0.05 Hz and frequency equal to 0.5 Hz and triangular voltage with 2 V amplitude and frequency of 0.005Hz. b) Results from one whole apple (A) shown for applied sinusoidal voltage with an amplitude of 2.5 V and frequency of 0.05 Hz and 0.5 Hz and triangular voltage with an amplitude of 4 V and frequency of 0.005 Hz. At frequencies of 0.05Hz and 0.5Hz, the results from the silver/silver chloride electrode recordings are already linear, since a straight line in the voltage current plots can be observed. The needle electrode recordings are still non-linear at these frequencies. c) Results from another whole apple (D) and from a piece of an apple shown for sinusoidal voltage with an amplitude of 4 V shown for frequency f = 0.005 Hz. The recordings on the apple pieces are quite similar to the recordings at the whole apples except that the recorded currents are higher. Saturation of the operational amplifier in the measurement channel of the needle electrode is reached and currents larger than about 175 μA could not be read.

Additional voltage current plots, always shown for the second period of each measurement. These extra measurements were done in December 2019 with a sinusoidal voltage with an amplitude of 4 V and a frequency of 0.005 Hz. Results from the silver/silver chloride electrode, the stainless steel electrode and a platinum wire (diameter of 0.4mm and length of 1cm) are presented as dark blue, light blue and green plots, respectively. Parts of the isolation of the stainless steel electrode were scratched which means that the active electrode area was larger than the electrode tip. The measurements were done after each other using only one reading channel with Rfb1=0.56 kΩ. a) Measurements in HCL acid that was diluted with deionized water. The overall pH-value of the solution was 3. Redox reaction of water is happening on all three electrode types. b) Measurement with the platinum wire in apple juice from concentrate.

eISSN:: 1891-5469
Idioma:: Inglés

Calendario de la edición:: Volume Open
Temas de la revista:: Engineering, Bioengineering and Biomedical Engineering, Biomedical Electronics, Life Sciences, Biophysics, Medicine, Biomedical Engineering, Physics, Spectroscopy and Metrology

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