Transient convective diffusion to a circular sink at finite Peclet number

Wein, O.; Tovcigrecko, V.; Sobolı́k, V.

doi:10.1016/j.ijheatmasstransfer.2006.05.002

Cited by 13 publications

(18 citation statements)

References 16 publications

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“…neglecting all but diffusion resistances, the overall transient course of fluxes was analyzed in [5]. In the present notation, and extending the LDC regime results to reversible electrodes, the final result can be written as:…”

Section: An Ultimate Asymptotementioning

confidence: 99%

“…for a disk electrode in a steady flow with the wall shear rate c, given in [5], can be also modified to an estimate for reversible electrodes:…”

Section: An Ultimate Asymptotementioning

confidence: 99%

“…In such a case, the Ohmic loss according to Eq. 9 (second part of the equation) introduces a substantial non-linearity, which has been analyzed for negligible Faradaic losses in [5]. Our results for the combined Ohmic and Faradaic resistances, published in Russian [7], provide only qualitative estimates of limited relevance.…”

mentioning

confidence: 95%

“…United boundary-value constraint for the concentration driving force q T Partial derivative with respect to T l : The voltage-step transient (VST) process in an electrochemical cell with a motionless electrolyte solution can be of interest both for studying the kinetics of electrode reactions [1][2][3] and for measuring the diffusion coefficients of depolarizers [4,5]. The VST process in the three-electrode electrochemical cells (with reference electrode) is commonly taken as a potentiodynamic one, i.e.…”

mentioning

confidence: 99%

“…with negligible additional transport resistances in the electrochemical cell and outer circuits. Such an assumption cannot be strictly right [1][2][3][4][5], for at least two reasons:…”

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confidence: 99%

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Voltage-step transient on circular electrodes

Wein

Tovchigrechko

2011

J Appl Electrochem

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Using the well-known Cottrell asymptote, voltage-step transient (VST) experiments in a two-electrode cell may provide data on the bulk concentration and diffusion coefficient of a working depolarizer, essential for interpretation of liming-diffusion-current (LDC) experiments. However, the Cottrell asymptote is never applicable in the early stages of the voltage-step transient process.There are three additional transport resistances to the basic diffusion transport that cannot be neglected at extremely high initial currents: Faradaic resistance at the working electrode surface, overall Ohmic losses in the electrochemical cell, and a possible galvanometric constraint in the outer circuit, involving the galvanometer, current follower, potentiostat, etc. The effect of these additional transport resistances on the transient current at higher polarization voltage is non-linear. In the present analysis, a 1D approximation is used, assuming tacitly uniform accessibility of the working electrode and negligible transport resistances at the counter electrode. The Faradaic resistance of a redox couple O ? ne -= R according to ButlerVolmer electrode kinetics is considered. The results of 1D theory are corrected for edge effects using the Oldham asymptote. The effect of convection at longer times is included using the recent model of a transient process for circular working electrodes in the LDC regime. List of symbols Variables AEffective area of working electrode, m 2 A ? area of ideally smooth working electrode, m 2 B:c B;W O;R Molar concentration of depolarizers and their boundary values (mol m -2 s -1 ) D, D O,R Coefficient of diffusion; values for the components (m 2 s -1 ) d À1=2 T Semi-integral operator E = Exp[P] f = (E -1)/(E?B), Nernst-Petersen factor G = k G /k S , normalized galvanometric constraint I Current (A) J O,R Diffusion fluxes of depolarizers at surface (mol m -2 s -1Rate constant factor in Butler-Volmer kinetics (m s -1 ) k C = U/(nFAR C c B work ), Ohmic limit for k(t) (m s -1 ) k G = I G /(nFA c B work ), galvanometric constraint (m s -1 ) k S = lk C , starting (upper) limit for k(t) (m s -1 ) L C Equivalent resistor length (m) M: K/k C nFThe charge transfer per 1 mol of the working depolarizer (C mol -1 ) N = N(T) : k/k S , normalized flux O. Wein (&) Á

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Section: An Ultimate Asymptotementioning

confidence: 99%

“…for a disk electrode in a steady flow with the wall shear rate c, given in [5], can be also modified to an estimate for reversible electrodes:…”

Section: An Ultimate Asymptotementioning

confidence: 99%

mentioning

confidence: 95%

mentioning

confidence: 99%

“…with negligible additional transport resistances in the electrochemical cell and outer circuits. Such an assumption cannot be strictly right [1][2][3][4][5], for at least two reasons:…”

mentioning

confidence: 99%

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Voltage-step transient on circular electrodes

Wein

Tovchigrechko

2011

J Appl Electrochem

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Application of the Electrodiffusion Method to Measure Wall Shear Stress: Integrating Theory and Practice

et al. 2014

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The electrodiffusion method has been used in fluid dynamic research for the past 50 years. It allows the measurement of wall shear stress, a crucial parameter, e.g., for the cleaning of membrane modules used in water filtration. Various authors have published articles dealing with the theory behind this technique. But no paper collects all the knowledge assembled over five decades of application. Here, comprehensive summary of the theory of steady flow, unsteady flow, and transient voltage step experiments is given. Factors influencing the accuracy of the measurements are discussed. Furthermore, a new approach to calibrate the system from voltage step experiments is introduced, and practical issues related to its application in flow measurements are discussed for an exemplary signal response to a near‐wall flow.

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Click Reaction as a Tool to Combine Pharmacophores: The Case of Vismodegib

et al. 2015

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The design and the preparation of a small library of 1,4‐diphenyl‐1,2,3‐triazole derivatives is reported, with the aim to obtain a new class of Hedgehog pathway inhibitors. The smoothened protein is part of the hedgehog signaling pathway that is inhibited by the lead compound Vismodegib. Based on molecular modeling simulations, seven triazole derivatives of Vismodegib are synthesized and their biological effect on different endothelial, cancer, and cancer stem cell lines is reported.

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Transient convective diffusion to a circular sink at finite Peclet number

Cited by 13 publications

References 16 publications

Voltage-step transient on circular electrodes

Voltage-step transient on circular electrodes

Application of the Electrodiffusion Method to Measure Wall Shear Stress: Integrating Theory and Practice

Click Reaction as a Tool to Combine Pharmacophores: The Case of Vismodegib

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