scholarly journals Frequency Responses of Molar Electrochemical Peltier Heat and Entropy Changes Analyzed as Thermometric Transfer Functions

2021 ◽  
Author(s):  
Moises Sanchez-Amaya ◽  
Maximiliano Bárcena-Soto ◽  
Rene Antano-Lopez ◽  
Aaron Rodríguez-López ◽  
Alberto Gutiérrez-Becerra ◽  
...  
Keyword(s):  
Transfer Functions ◽  
Electrochemical Impedance ◽  
Copper Ions ◽  
Electrical Signal ◽  
Relaxation Processes ◽  
Chloride Medium ◽  
Entropy Changes ◽  
Sulphate Chloride ◽  
Interfacial Temperature ◽  
Electrochemical Peltier Heat

Abstract This work proposes a theoretical framework to obtain the frequency response of molar electrochemical Peltier heat and entropy changes induced by a modulated electrical signal. This is based on an internal energy balance developed for a working electrode thermistor in ac regime. Then, from an analysis that correlates the electrochemical impedance and the interfacial temperature variation, two new transfer functions that depend on the frequency ω, named as entropy changes ∆S(ω), and molar electrochemical Peltier heat, Π(ω) are obtained. This strategy is tested in two electrochemical systems: the ferrocyanide/ferricyanide couple and the copper ions in an acid sulphate-chloride medium. Both systems are analyzed by dc thermometric measurements, electrochemical impedance spectroscopy and ac-thermometric experiments namely variation of interfacial temperature. As a result, ∆S(ω) and Π(ω), are obtained and their values are correlated to the relaxation processes involved in the electrochemical reaction. Additionally, a brief discussion is included concerning the differences between the classical dc thermoelectrochemical methodology and the proposed approach here.

THE STUDY ON NOVEL MICROELECTRODE ARRAY CHIPS FOR THE DETECTION OF HEAVY METALS IN WATER POLLUTION

2012 ◽  
Vol 05 (01) ◽  
pp. 1150002 ◽  
Author(s):  
HUI-XIN ZHAO ◽  
WEI CAI ◽  
DA HA ◽  
HAO WAN ◽  
PING WANG
Keyword(s):  
Heavy Metals ◽  
Microelectrode Array ◽  
Electrochemical Impedance ◽  
Copper Ions ◽  
Rapid Development ◽  
Anodic Stripping Voltammetry ◽  
Aqueous Environment ◽  
Mercury Film ◽  
Voltammetric Detection ◽  
Cadmium Lead

Qualitative and quantitative analysis of trace heavy metals in aqueous environment are rapidly assuming significance along with the rapid development of industry. In this paper, gold microelectrode array (MEA) plated with mercury film was used for simultaneous voltammetric detection of zinc, cadmium, lead and copper ions in water. The electrochemical behavior and the actual surface area of the MEA were investigated by cyclic voltammetry in K3[Fe(CN)6] . Electrochemical impedance spectrum (EIS) was utilized to examine the deposition of mercury on the electrode surface. Based on anodic stripping voltammetry, mercury film– Au MEA was applied to the detection of heavy metals in artificial analyte, where good calibrate linearity was obtained for cadmium, lead and copper ions, but with zinc exhibiting poor linearity.

Inhibitory Action of Persian Pyrifoliabark Extract against Corrosion of SAE 1020 Carbon Steel in Sodium Chloride Medium

2020 ◽  
Vol 1012 ◽  
pp. 390-394
Author(s):  
C. Vieira ◽  
D. Borges ◽  
D.C.S. Oliszeski ◽  
L.F.G. Larsson ◽  
E.P. Banczek
Keyword(s):  
Sodium Chloride ◽  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Steel Corrosion ◽  
Industrial Applications ◽  
Protective Film ◽  
Chloride Medium ◽  
Simple Extraction ◽  
Extraction Processes

Carbon steel is one of the most commonly used alloys in industrial applications due to its physicochemical properties and low cost. However, the use of this metal material may become limited due to its vulnerability to corrosion. Thus, it is necessary to use methods that inhibit corrosion. Organic compounds with heteroatoms possess the characteristic of inhibiting corrosion by forming a protective film. The corrosion protection of SAE 1020 carbon steel, promoted by the aqueous extract of Persea pyrifolia (PP) bark, was evaluated in this work at extract concentrations of 5% and 10% v/v, in order to replace an inhibitor of synthetic origin with an ecologically benign inhibitor. Plant extracts are generally inexpensive and can be obtained through simple extraction processes. The objective of this work was to study the use of PP peel extract as a carbon steel corrosion inhibitor (SAE 1020). The electrochemical response was determined by measurements including electrochemical impedance spectroscopy (EIS) and anodic potentiodynamic polarization (PPA) in a 0.5 M sodium chloride medium. The samples were characterized by optical microscopy to evaluate the type of corrosion.

Reduced Order Impedance Models of Lithium Ion Batteries

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Githin K. Prasad ◽  
Christopher D. Rahn
Keyword(s):  
Lithium Ion Batteries ◽  
Transfer Functions ◽  
Electrochemical Impedance ◽  
Active Material ◽  
Lithium Ion ◽  
Particle Model ◽  
Simulation Design ◽  
Material Particle ◽  
Reduced Order ◽  
Cell Parameters

This paper develops reduced order, linear models of lithium ion batteries that can be used for model-based power train simulation, design, estimation, and controlling in hybrid and electric vehicles (HEV). First, a reduced order model is derived from the fundamental governing electrochemical charge and Li+ conservation equations that are linearized at the operating state of charge and low current density. The equations are solved using analytical and numerical techniques to produce the transcendental impedance or transfer function from input current to output voltage. This model is then reduced to a low order state space model using a system identification technique based on least squares optimization. Given the prescribed current, the model predicts voltage and other variables such as electrolyte and electrode surface concentration distributions. The second model is developed by neglecting electrolyte diffusion and modeling each electrode with a single active material particle. The transcendental particle transfer functions are discretized using a Padé Approximation. The explicit form of the single particle model impedance can be realized by an equivalent circuit with resistances and capacitances related to the cell parameters. Both models are then tuned to match experimental electrochemical impedance spectroscopy (EIS) and pulse current-voltage data.

scholarly journals Equivalent Circuits Applied in Electrochemical Impedance Spectroscopy and Fractional Derivatives with and without Singular Kernel

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
J. F. Gómez-Aguilar ◽  
J. E. Escalante-Martínez ◽  
C. Calderón-Ramón ◽  
L. J. Morales-Mendoza ◽  
M. Benavidez-Cruz ◽  
...  
Keyword(s):  
Fractional Derivatives ◽  
Transfer Functions ◽  
Electrochemical Impedance ◽  
Equivalent Circuits ◽  
Electrical Parameters ◽  
Electrical Circuits ◽  
Laplace Domain ◽  
Alternative Representation ◽  
Electrochemical Systems ◽  
Cole Model

We present an alternative representation of integer and fractional electrical elements in the Laplace domain for modeling electrochemical systems represented by equivalent electrical circuits. The fractional derivatives considered are of Caputo and Caputo-Fabrizio type. This representation includes distributed elements of the Cole model type. In addition to maintaining consistency in adjusted electrical parameters, a detailed methodology is proposed to build the equivalent circuits. Illustrative examples are given and the Nyquist and Bode graphs are obtained from the numerical simulation of the corresponding transfer functions using arbitrary electrical parameters in order to illustrate the methodology. The advantage of our representation appears according to the comparison between our model and models presented in the paper, which are not physically acceptable due to the dimensional incompatibility. The Markovian nature of the models is recovered when the order of the fractional derivatives is equal to 1.

scholarly journals Development of an impedimetric sensor based on carbon dots and chitosan nanocomposite modified electrode for Cu (II) detection in Water

2021 ◽  
Author(s):  
mosaab echabaane ◽  
Salwa Hfaiedh ◽  
Badreddine Smiri ◽  
Fawzi Saidi ◽  
Cherif Dridi
Keyword(s):  
Carbon Dots ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Copper Ions ◽  
Hydroxyl Groups ◽  
Water Safety ◽  
Acidic Aqueous Solution ◽  
Safety Control ◽  
Transmission Electron ◽  
Film Electrolyte

Abstract The fast and sensitive detection of copper ions would be essential for water monitoring. Herein, we report a novel development of impedimetric sensor based on carbon dots/chitosan nanocomposite. Carbon dots (CDs) were synthesized by simple heating of acidic aqueous solution of glucose. The CDs were characterized by TEM, FTIR, XRD, UV-visible, and PL. These measurements revealed that the CDs possess a mean size of 3.2 nm, graphitic structure with carboxyl and hydroxyl groups on the surface, and show particular optical properties. A glassy carbon electrode (GCE) was modified with a carbon dots/chitosan (CHITO) nanocomposite, and was characterized by transmission electron microscopy and electrochemical impedance spectroscopy (EIS). The CDs-CHITO/GCE electrode exhibits large surface area, good conductivity film, and charge transfer at interface film/electrolyte. The proposed impedimetric sensor exhibits a linear response to Cu(II) over 10-9 M to 10-5 M rang with a limit of detection at about 5×10-10 M. In addition, the sensor shows good selectivity toward Cu(II) ions, which is less than 5 %.Therefore, the as-developed impedimetric sensor exhibits good reproducibility, stability, selectivity, and a low limit of detection, which augur well for its application in water safety control processes.

scholarly journals Unexpected effect of copper ions on electrochemical impedance behaviour of self-assembled alkylaminethiol monolayer

2013 ◽  
Vol 33 (1) ◽  
pp. 64-66
Author(s):  
Paul-Louis Fabre ◽  
Laure Latapie ◽  
Jérôme Launay ◽  
Olivier Reynes ◽  
Pierre Temple-Boyer
Keyword(s):  
Electrochemical Impedance ◽  
Copper Ions ◽  
Unexpected Effect ◽  
Self Assembled ◽  
Effect Of Copper

scholarly journals Relaxation phenomena of electrical signal emissions from rock following application of abrupt mechanical stress

2012 ◽  
Vol 55 (1) ◽  
Author(s):  
Dimos Triantis ◽  
Filippos Vallianatos ◽  
Ilias Stavrakas ◽  
George Hloupis
Keyword(s):  
Mechanical Stress ◽  
Applied Stress ◽  
Rock Sample ◽  
High Stress ◽  
Electrical Signal ◽  
Relaxation Processes ◽  
Significant Information ◽  
Stress Levels ◽  
High Level ◽  
Clear Information

<p>The emission of electrical signals during application of mechanical stress to brittle geo-materials (the so-called pressure-stimulated current; PSC) can provide significant information regarding the mechanical status of a studied rock sample. PSCs originate as a result of the opening of cracks and microfractures in rock. In this study, such electrical signal emissions are detected and studied when rock samples are subjected to step-wise mechanical stress, increased from low stress levels vL up to higher stress levels vH. This increase is performed at high stress rates and consequently the stress is maintained practically constant for a long period. During this time, the applied stress reaches its maximum value, and the emitted PSC decays gradually and relaxes back to a minimum value. The conducted experiments suggest that the characteristics of the relaxation processes of the PSC depend directly on the high level of the applied stress that is maintained constant after the application of each stress step. Analysis of the macroscopic parameters that characterize the relaxation phenomenon of the PSC provides clear information regarding the proximity of the applied stress to the fracture limit of the rock sample.</p>

scholarly journals Continuous and controllable electro-fabrication of antimicrobial copper-alginate dressing for infected wounds treatment

2021 ◽  
Vol 32 (12) ◽  
Author(s):  
Shijia Wang ◽  
Xiaoli Liu ◽  
Miao Lei ◽  
Junjie Sun ◽  
Xue Qu ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Copper Ions ◽  
Wide Spectrum ◽  
Electrical Signal ◽  
Wound Dressings ◽  
In Vitro Tests ◽  
Wound Treatment ◽  
Infected Wound

AbstractThe contamination of chronic wound with bacteria especially methicillin-resistant Staphylococcus aureus (MRSA) is considered as the major factor interferencing normal wound healing. There still remain great challenges in developing safe and effective wound dressings with wide-spectrum antibacterial functions. Alginate hydrogel is a common dressing for wound treatment. Copper is one of the trace elements in human body with inherent antibacterial activity. Traditional methods for preparing a structure-controlled copper-alginate antibacterial matrix are difficult however, due to the fast and uncontrolled gelation between alginate and metal ions. In this work, we report an electrodeposition method for rapid fabrication of copper cross-linked alginate antibacterial films (Cu2+-Alg) with controlled structure and copper content, which is relied on an electrical signal controlled release of copper ions from the reaction of insoluble salt Cu2(OH)2CO3 and the generated protons via water electrolysis on anode. The results prove that the physical structure and chemical composition of the electrodeposited Cu2+-Alg films can be continuously modulated by the imposed charges during electrodeposition. In vitro tests demonstrate the film has Cu2+ content-dependent bactericidal activities. Film’s cytocompatibility is well controlled by the imposed charges for Cu2+-Alg fabrication. The MRSA infected wound model in vivo also indicates that Cu2+-Alg film can effectively eliminate bacterial infection and suppress host inflammatory responses. We believe this study demonstrates a convenient and controllable strategy to fabricate alginate antibacterial dressings with potential applications for infected wound treatment. More broadly, our work reveals electrodeposition is a general and simple platform to design alginate films with versatile functions.

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