Electromotive Force Data Research Articles

Modeling of an inductive displacement sensor based on 1DCNN-LSTM-AT

Abstract The input-output relationship of inductive displacement sensors is typically nonlinear, which demands numerous computational resources for precise calculation. Therefore, the traditional analytical methods for the inductive displacement sensors cannot meet the real-time high-precision measurement requirements. In response to the aforementioned issues, this paper proposes an optimized Long Short-Term Memory (LSTM) neural networks based on one-dimensional convolutional neural networks (1DCNN) to modeling the input-output relationship of the inductive displacement sensor. First, the measurement principle of the inductive displacement sensors was analyzed, and the analytical model of the sensor output was derived. And the influences of the key parameters of sensors on the relationship between the induced voltage and the displacement were studied. Then, the 1DCNN-LSTM-AT network for modelling the input-output relationship of the inductive displacement sensor was studied. The spatial features of historical induced electromotive force (EMF) data generated by the induction coil were initially extracted using the 1DCNN network. And these spatial features were then utilized as input to the LSTM neural network to capture the temporal features of the historical induced EMF data. Subsequently, the spatiotemporal features of the induced EMF data were fed into the regression prediction layer to compute the displacement measurement results corresponding to the current input. Moreover, the attention mechanism was used for the 1DCNN-LSTM model to enhance the prediction accuracy and stability of the model. Finally, the experimental results demonstrate that the proposed 1DCNN-LSTM-AT model achieves an average absolute percentage error (MAPE) of 3.1%, significantly outperforming traditional models such as LSTM (29.3%), CNN (4.7%), and ANN (4.3%). This paper provides a new method for modelling the nonlinear relationships of the inductive displacement sensor, and presents a fresh perspective for research in the data processing of nonlinear sensors.

Thermodynamic modeling of the Ta-O system

CALPHAD (CALculation of PHAse Diagrams) thermodynamic models of the Ta-O system are developed using experimental data from the literature and are supplemented by first-principles calculations. The standard-pressure equilibrium polymorphs of α and β Ta2O5 are modeled as stoichiometric compounds with tabulated thermochemical data. The metallic phase, body-centered cubic (BCC) Ta, has significant O solubility at high temperatures. A sublattice model of the BCC phase is fit to electromotive force (EMF) and metallographic data to obtain thermodynamic values for O dissolution in Ta. First-principles calculations of the enthalpies of mixing for O in BCC Ta and enthalpies of formation for β-Ta2O5 agree with the modeled and experimental data. The liquid Ta-O phase lacks data, but preliminary associate solution and ionic liquid models are fit to the metallographic data from the literature. The calculated phase diagrams are consistent with existing experimental phase diagrams.

Analytical prediction of heat capacity of molten AgCl and CuCl with application to thermochemical Cu-Cl cycle for hydrogen production

To sustain our power-dependent world, there is a need for technological innovation in all aspects of science and engineering. Many times, thermophysical and material properties are not well defined for the specific application, which leads to implementing assumptions and approximations from the published data. In the thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen (H2) production, heat is recovered from cuprous chloride (CuCl) molten salt and it is then reacted with hydrochloric acid (HCl) in stoichiometric proportions to produce the anolyte for the H2 production step of the cycle. However, the lack of precise thermophysical properties on CuCl heavily hinders the detailed investigations of heat recovery from the molten salt as it cools from 450 °C to 90 °C. In this paper a new method is developed to determine the thermophysical property of CuCl and silver chloride (AgCl) as the molten salts are changing phases to solid. This is achieved by correlating electrochemistry data with thermal data. A model that predicts the specific heat capacity during phase change process is developed based on the existing electromotive force (EMF) and thermal data from literature. Developed model shows the EMF derived specific heat capacity values of AgCl and CuCl are similar with a slight offset since they have similar EMF's at higher temperatures.

Investigation in the variation of Gibbs energy of formation of RE6UO12 (RE = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) along the 4f series

The RE6UO12 (s) (RE = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) compounds were synthesized by citrate nitrate combustion method and characterized by X-Ray Diffraction (XRD) technique. Standard molar Gibbs energy of formation of RE6UO12(s) (RE = La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu) was determined from the equilibrium electromotive force (e.m.f) data obtained from solid-state Galvanic cell with oxide ion conducting yttria-stabilized-zirconia (YSZ) electrolyte. The cells were operated under high pure argon atmosphere. E.m.f. measurements were carried out in the temperature range of 850–1150 K. Phase transition in Sm6UO12(s) and Yb6UO12(s) were detected at 1125 K and 1065 K, respectively. The transition temperatures were confirmed from high temperature XRD technique. The standard enthalpy of formation and entropy at temperature of 298.15 K for RE6UO12 (s) was calculated from the Gibbs energy data using second and third law analysis and the data were compared with the corresponding data reported for RE2O3(s). Similar trend in enthalpy as well as entropy was observed for RE6UO12 (s) and RE2O3 (s) along the series of 4f elements.

Fusion of Spectroscopy and Cobalt Electrochemistry Data for Estimating Phosphate Concentration in Hydroponic Solution.

Phosphate is a key element affecting plant growth. Therefore, the accurate determination of phosphate concentration in hydroponic nutrient solutions is essential for providing a balanced set of nutrients to plants within a suitable range. This study aimed to develop a data fusion approach for determining phosphate concentrations in a paprika nutrient solution. As a conventional multivariate analysis approach using spectral data, partial least squares regression (PLSR) and principal components regression (PCR) models were developed using 56 samples for calibration and 24 samples for evaluation. The R2 values of estimation models using PCR and PLSR ranged from 0.44 to 0.64. Furthermore, an estimation model using raw electromotive force (EMF) data from cobalt electrodes gave R2 values of 0.58–0.71. To improve the model performance, a data fusion method was developed to estimate phosphate concentration using near infrared (NIR) spectral and cobalt electrochemical data. Raw EMF data from cobalt electrodes and principle component values from the spectral data were combined. Results of calibration and evaluation tests using an artificial neural network estimation model showed that R2 = 0.90 and 0.89 and root mean square error (RMSE) = 96.70 and 119.50 mg/L, respectively. These values are sufficiently high for application to measuring phosphate concentration in hydroponic solutions.

Formula omitted] couple in LiCl-KCl eutectic: Anodic polarization of thorium and electrochemical impedance spectroscopy study at tungsten, cadmium and thorium electrodes

Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate electrochemical behaviour of thorium at inert tungsten, liquid cadmium and thorium electrodes in LiCl-KCl eutectic. Equilibrium potentials of Th4+|Th couple were measured from the cyclic voltammograms at thorium electrode in LiCl-KCl-ThCl4 electrolyte and compared with theoretically estimated equilibrium potential using ΔfGThCl4,LiCl−KCl∘, ΔfGThCl4,liq.∘ and γThCl4 from literature sources as input. It was observed that deviation of estimated values from measured data of −1.437 V at 773 K could be ascribed not only to different experimental conditions employed but also to difference in ΔfGThCl4,liq.∘ values taken from various thermochemical data compilations. Considering all experimental uncertainties and errors in linear fitting of electromotive force data from literature sources, theoretical equilibrium potential of thorium dissolution was estimated at −1.462 ± 0.065 V (vs.Ag+|Ag as ref.) for xThCl4 = 3.86 × 10−3 at 773 K. Complex impedance plots were recorded for inert tungsten, liquid cadmium and thorium electrodes at various applied potentials in the frequency and temperature range of 10 Hz-10 kHz and 698–798 K, respectively. They were further validated using Kramers-Kronig transforms and interpreted using equivalent circuit model consisting of melt resistance (Rs), charge transfer resistance (Rct) and constant phase elements (Q) as circuit components. Mechanism of anodic dissolution of thorium in LiCl-KCl eutectic melt was proposed, which was based on semi-infinite Warburg diffusion at lower frequencies having slope greater than unity and double layer capacitance at higher frequencies due to partial accumulation of Th4+ ions at the electrode-electrolyte interface. Heterogeneous rate constant estimated from Rct was used to address reversibility of Th4+|Th couple using Matsuda-Ayabe criteria for anodic (thorium electrode) and cathodic polarization (inert tungsten) cases, which was found to be quasi-reversible in the scan rate range 10–100 mV/s and temperature range 698–798 K.

Thermodynamic Properties of Tl9GdTe6 and TlGdTe2

The results of a thermodynamic study of the Tl2Te–Tl2Te3–TlGdTe2 system by the electromotive force (EMF) method in the temperature range 300–450 K were presented. The partial thermodynamic functions of GdTe and Gd in alloys were first determined from the experimental EMF data for concentration cells relative to the GdTe electrode. The standard thermodynamic functions of formation and standard entropies of Tl9GdTe6 and TlGdTe2 were calculated based on these data.

Neural Network for Mapping Full Time Apparent Resistivity Solution from TEM Electromotive Force Data

The apparent resistivity of the induced electromotive force observed by the transient electromagnetic (TEM) in center loop is proposed by using the neural network. According to the characteristics of increasing of the induced electromotive force with the resistivity of the transient electromagnetic sounding, the neural network input and output relationship and the network structure of the transient electromagnetic induction electromotive force response are designed according to the uniform half space central line observation mode. The nonlinear model of transient electromagnetic induction electromotive force and apparent resistivity is fitted by the neural network to obtain the full apparent resistivity value of the measured induced electromotive force data at a certain sampling time, and the aim of resistivity and imaging is achieved quickly. Through the calculation and verification of the simulation model of the transient electromagnetic in grounding grids, the apparent resistivity section can be obtained, and the position of the breakpoint can be clearly determined, and the effect of solving the inverse problem is achieved. The calculation of the verification model shows that the method makes the calculation time of the transient electromagnetic apparent resistivity greatly shorten, which is a practical algorithm.

Thermodynamic study of potassium chloride in glycerol–water mixed solvents using electromotive force measurements at (298.2, 303.2 and 310.2) K

The mean activity coefficients of KCl were determined in glycerol–water mixed solvents, in the range of (0, 10, 20, 30, and 40)% of glycerol, from the electromotive force (EMF) data at (298.2, 303.2, and 310.2)K. The Pitzer equations were used to describe non-ideal behavior of the electrolyte, and the corresponding activity and osmotic coefficients were determined. Moreover, Pitzer parameters, the excess Gibbs free energy and solvent activity of KCl–glycerol–water system were calculated.

Phase equilibria in the Tl–TlI–Se system and thermodynamic properties of the ternary phases

By using differential thermal analysis (DTA), X-ray analysis and electromotive force (EMF) methods the Tl–Se–I system was investigated in the Tl–TlI–Se composition range. Several polythermal sections, the isothermal section at 300K and the projection of the liquidus surface of the system were constructed. The fields of primary crystallization of phases as well as types and coordinates of non- and monovariant equilibria were determined. Formation of two congruently melting ternary compounds (Tl5Se2I at 720K, and Tl6SeI4 at 705K) was observed. The system is characterized by the existence of wide areas of solid solutions on the base of Tl2Se (α-phase) and Tl5Se2I (δ-phase). The partial molar thermodynamic functions (ΔG‾,ΔH‾,ΔS‾) of thallium as well as the standard integral thermodynamic functions of Tl6SeI4 and Tl5Se2I compounds and Tl5Se3−xIx solid solution (for x=0.2, 0.4, 0.5, and 0.8) were calculated based on the EMF data.

Experimental investigations and thermodynamic modelling of KCl–LiCl–UCl3 system

Experimental investigations and Gibbs energy modelling of KCl–LiCl–UCl3 system employing CALPHAD method are reported. Gibbs energy modelling of the subsystems KCl–UCl3 and LiCl–UCl3 was carried out primarily using phase diagram data from the literature. For the Gibbs energy modelling of the KCl–LiCl subsystem, new phase boundary data corresponding to four terminal compositions (xLiCl=0.03, 0.05, 0.95 and 0.97) obtained through differential thermal analysis data along with thermochemical and phase diagram data from the literature were used. Thermal analysis was also carried out for KCl–LiCl eutectic mixture containing small amounts of UCl3(xUCl3=9.03×10−3 and 1.79×10−2). The liquidus temperatures for these compositions were found to be 637K and 674K. Electromotive force data for dilute solutions of UCl3 in the KCl–LiCl eutectic melt, measured in the temperature range 708–833K in the present work, were found to be in good agreement with the literature data. These data were also used as input for the Gibbs energy modelling of the KCl–LiCl–UCl3 system. In order to improve the quality of the resulting Gibbs energy functions of the quasibinaries and the quasiternary, enthalpies of mixing of the corresponding melts estimated using an empirical correlation based on surrounded-ion model were also used as input. Finally, the generated Gibbs energy functions were used to compute phase equilibria.

Thermodynamic properties of Ag3AuSe2 from 300 to 500K by a solid state galvanic cell

The numerical values of the standard thermodynamic functions of Ag3AuSe2 (fischesserite) in the Ag–Au–Se system were determined by the electromotive force (EMF) method in a solid state galvanic cell with RbAg4I5 as the solid electrolyte below 500 K. Ag3AuSe2 was synthesized from pure elements in stoichiometric composition by evacuated ampoules made of quartz glass. On the basis of EMF vs. temperature experimental data, the analytical equations were obtained, from which the temperature dependent relationships of the Gibbs energy in the relevant reactions and the standard thermodynamic functions of Ag3AuSe2 within the temperature range of 300–500 K were calculated. The results show that there is possible a new polymorphic transformation around 350 K.

Thermodynamic properties of liquid Au–Cu–Sn alloys determined from electromotive force measurements

The thermodynamic properties of the ternary Au–Cu–Sn system were determined with the electromotive force (EMF) method using a liquid electrolyte. Three different cross-sections with constant Au:Cu ratios of 3:1, 1:1, and 1:3 were applied to measure the thermodynamic properties of the ternary system in the temperature range between the liquidus temperature of the alloys and 1023K. The partial free energies of Sn in liquid Au–Cu–Sn alloys were obtained from EMF data. The integral Gibbs free energy and the integral enthalpy at 900K were calculated by Gibbs–Duhem integration. The ternary interaction parameters were evaluated using the Redlich–Kister–Muggianu polynomial.

Activity Coefficients of Potassium Chloride in Ethylene Glycol−Water Mixtures Using Electromotive Force Measurements at (278.15, 288.15, 298.15, and 308.15) K

The mean activity coefficients of KCl were determined in ethylene glycol−water mixed solvents, in the range of (10, 20, 30, and 40) % ethylene glycol, from the electromotive force (EMF) data at (278.15, 288.15, 298.15, and 308.15) K. The Pitzer and extended Debye−Hückel equations were used to describe the nonideal behavior of the electrolyte, and the corresponding activity and osmotic coefficients were determined. Moreover, the standard Gibbs energy of transference of KCl−ethylene glycol−water was evaluated.

Dynamics of TiO2-based photoelectrochemical cell

The present work reports the effect of light on the open-circuit voltage of a photoelectrochemical cell (PEC) formed of TiO2 photoanode, Pt cathode and Na2SO4 (0.35 M) aqueous solution as electrolyte. The studies included the measurements of the electromotive force (EMF) during the light-off and light-on cycles for the PEC involving photoanode that was made of both oxidised and reduced TiO2 thin films. These specimens were formed by oxidation of the titanium metal at high and low oxygen activities. This was achieved by the imposition of the gas phase of two different compositions, including air, p(O2) = 21 kPa, and the hydrogen–water vapour mixture, $p({\rm O}_2) = 10^{-10}$ Pa, at 1,123 K and subsequent cooling to room temperature. The determined data indicate that the PEC formed of the oxidised specimen exhibits larger EMF and a substantially better stability in time. It is, therefore, concluded that the TiO2 obtained in air exhibits superior performance-related properties compared to the reduced specimen. The obtained experimental EMF data are considered in terms of the effect of light on the reactivity of TiO2 with oxygen and water and the related charge transfer.

Interaction of anionic azo dye and TTAB: cationic surfactant

Interaction between three anionic azo dyes, C.I. Acid Red 14 (AR14), C.I. Acid Red 1 (AR1), C.I. Acid Orange 7 (AO7) and a cationic surfactant tetradecyltrimethylammonium bromide (TTAB) has been investigated using surfactant selective electrode technique. The TTAB selective electrode was constructed and used to determine the concentration of TTAB monomers and also surfactant ions bounded to dyes by electromotive force data. The dye-surfactant complex formation constant, K1, and the standard free energy change, ΔG1o, could be obtained from the experimental data. The results indicate that in the TTAB/AO7 system, where the more hydrophobic dye AO7 is used, the dye-surfactant interactions are stronger than in other systems. The results also indicate that both the electrostatic attractive and the hydrophobic interactions are very important for the formation of the complex between the oppositely-charged dyes and the surfactant. Maximum binding capacities of the dyes and also the degree of binding of the surfactant to the dyes were calculated from the experimental data.

Activity coefficients for NH 4Cl in 2-PrOH/water mixed solvent and some thermodynamic correlations for NH 4Cl in ROH/water mixed solvents (R = Me, Et, 1-Pr and 2-Pr)

In this work the results concerning the determination of the activity coefficients for NH 4Cl in 2-PrOH/water mixed solvents, along with some thermodynamic correlations concerning the resulting osmotic coefficients and excess Gibbs free energies for this electrolyte in different ROH/water mixed solvent systems (where R = Me, Et, 1-Pr and 2-Pr) are presented. These electrolytic systems were modeled using the Pitzer ion-interaction model and based on the experimental electromotive force (emf) data, of the following galvanic cell: Ag | AgCl | N H 4 Cl ( m ) , H 2 O ( 100 − w % ) , ROH ( w % ) | N H 4 + ISE , at 298.15 K. The results concern the previous and new collected experimental data using NH 4 + ion-selective PVC membrane and Ag/AgCl electrodes for different mass fraction percents ( w ) of alcohol in water (with w = 0 , 10 , 20 , and 30 % , and R = Me, Et, 1-Pr, and R = 2-Pr, respectively). The thermodynamic behavior of these electrolyte systems were determined over the molality ranging from dilute solution to near salt saturation, or to phase separation (e.g. R = 2-Pr) in these mixed solvent systems. The non-ideal behavior of these electrolyte systems were satisfactorily correlated in term of the linear dependence of the Pitzer ion-interaction parameters on the dielectric constant of the solvents, and also in term of the ion association phenomenon related to the Pitzer electrostatic interaction terms in the second virial coefficient for the used electrolytic systems.

On a recent purported determination of individual ion activity coefficients

AbstractIn a recent article “On the activity of ions and the junction potential: Revised values for all data,” G. Wilczek‐Vera, E. Rodil, and J. H. Vera proposed the amended version of a controversial method to derive ion activity coefficients from electromotive force data. Here we show that their method is incorrect. Using precise data available for HCl, we show that their approach does not identify an unequivocal single set of ion activity coefficients, but as many sets as those that are introduced as the input in the evaluation of the liquid junction potentials. That is, an infinite number of self‐consistent sets. Indeed, the “ion activity coefficients” found echo the starting assumptions, with no relationship to the actual, but unknown real values. © 2005 American Institute of Chemical Engineers AIChE J, 2006

Determination of activity coefficients for NH 4Cl in 1-propanol/water mixed solvents by potentiometric measurements

Activity coefficients for NH 4Cl in different 1-propanol/water mixed solvents were determined at 25 °C using experimental electromotive force (emf) data of the following galvanic cell: Ag | AgCl | NH 4 Cl ( m ) , H 2 O ( 100 − w % ) , 1 − PrOH ( w % ) | NH 4 + ( ISE ) , in which ISE stands for the ion-selective electrode and w for the mass fraction percent of 1-propanol. The measurements were performed in various mixed 1-propanol/H 2O solvent systems containing 0, 10, 20, 30, 40 and 50 mass fraction percent of 1-propanol, respectively. The experimental emf data were obtained by a solvent polymeric PVC ammonium-selective membrane electrode containing a mixture of nonactin/monactin as ionophore and an Ag/AgCl electrode. The non-ideal behavior of the electrolyte system was described, for each mixed solvent system, on the base of the Pitzer ion-interaction model by determining the related coefficients over the molality range from dilute solution to near salt saturation (i.e. about 5.13 mol/kg in pure water or 2.34 mol/kg in 50% mixed 1-propanol/water solvent).

Activity coefficients and thermodynamic parameters for RbCl/CsCl + amide (acetamide, propanamide, and n-butanamide) + water system at 298.15 K

Electromotive force (emf) of the chemical cell without liquid-junction K-ISE | RbCl/CsCl ( m E) | ISE-Cl and K-ISE | RbCl/CsCl ( m E), amide ( m N) | ISE-Cl, have been measured at 298.15 K, where m E = (0.005 to 0.5) mol kg − 1 and m N= (0.05 to 3.0) mol kg − 1 . The activity coefficients of RbCl/CsCl in amide (acetamide, propanamide, and n-butanamide) + water mixture can be obtained from these electromotive force data and in the mean time the Gibbs free energy interaction parameters of RbCl/CsCl + amide pair in water, g EN, as well as the salt constant, k S, can be evaluated. The results show that both g EN > 0, k S > 0 at 298.15 K, and all the activity coefficients of electrolyte in amide + water mixture increase with increasing the m N, but it is a little complicated for the dependence of activity coefficients on m E. These thermodynamic parameters were discussed in terms of a model of the structural interaction and electrostatic interaction and the dependence of them on the number of carbon atoms in amide as well as the radius of metal ions were interpreted by the group additivity principle.