The dissolution of copper metal by acidified iron(III) in acetonitrile-water solutions

1984 ◽  
Vol 37 (2) ◽  
pp. 231 ◽  
Author(s):  
RA Couche ◽  
IM Ritchie
Keyword(s):  
Diffusion Coefficient ◽  
Kinematic Viscosity ◽  
Copper Film ◽  
Viscosity Data ◽  
Kinetic Measurements ◽  
Mixed Control ◽  
Diffusion Controlled ◽  
Temperature Diffusion ◽  
Disc Rotation ◽  
Disc Rotation Speed

The kinetics and electrochemistry of the dissolution of a rotating copper disc in various acidified acetonitrile-water mixtures containing iron(III) as the oxidant are described. The reaction kinetics were investigated by a chronopotentiometric method in which the time taken for a copper film of known thickness to dissolve was determined. The reaction was shown to be diffusion-controlled over the temperature range (270-304 K) and composition range (1.0-14.5 mol dm-3 acetonitrile) investigated, good agreement being obtained between rate constants calculated from kinetic measurements and those calculated from electrochemical (cathodic polarization) measurements. From these and kinematic viscosity data, diffusion coefficients for iron(III) in acetonitrile-water mixtures were calculated. It was found that, associated with a discontinuous change in the kinematic viscosity at 290 K, there was a corresponding change in the diffusion coefficient. The activation energy for the high-temperature diffusion process was lower than that for the low-temperature process. It was also found that the diffusion coefficient decreased with increasing acetonitrile concentration. Corrosion potential measurements as a function of disc rotation speed and iron(III) concentration are reported. From these measurements, it was inferred that the anodic reaction is under mixed control.

scholarly journals Surface Thermodynamics, Viscosity, Activation Energy of N-Methyldiethanolamine Aqueous Solutions Promoted by Tetramethylammonium Arginate

Entropy ◽  
2020 ◽  
Vol 22 (12) ◽  
pp. 1337
Author(s):  
Xiangfeng Tian ◽  
Lemeng Wang ◽  
Pan Zhang ◽  
Dong Fu
Keyword(s):  
Activation Energy ◽  
Surface Tension ◽  
Diffusion Coefficient ◽  
Aqueous Solutions ◽  
Quantitative Relationship ◽  
Viscosity Data ◽  
Surface Thermodynamics ◽  
Surface Entropy ◽  
Operation Conditions ◽  
Surface Enthalpy

The surface tension and viscosity values of N-methyldiethanolamine (MDEA) aqueous solutions promoted by tetramethylammonium arginate ([N1111][Arg]) were measured and modeled. The experimental temperatures were 303.2 to 323.2 K. The mass fractions of MDEA (wMDEA) and [N1111][Arg] (w[N1111][Arg]) were 0.300 to 0.500 and 0.025 to 0.075, respectively. The measured surface tension and viscosity values were satisfactorily fitted to thermodynamic models. With the aid of experimentally viscosity data, the activation energy (Ea) and H2S diffusion coefficient (DH2S) of MDEA-[N1111][Arg] aqueous solution were deduced. The surface entropy and surface enthalpy of the solutions were calculated using the fitted model of the surface tension. The quantitative relationship between the calculated values (surface tension, surface entropy, surface enthalpy, viscosity, activation energy, and H2S diffusion coefficient) and the operation conditions (mass fraction and temperature) was demonstrated.

Vacancy Formation Energy and Kinetic Properties of Liquid Metals

2021 ◽  
Vol 880 ◽  
pp. 43-48
Author(s):  
Yuri N. Starodubtsev ◽  
V.S. Tsepelev
Keyword(s):  
Diffusion Coefficient ◽  
Kinematic Viscosity ◽  
Formation Energy ◽  
Liquid Metals ◽  
Linear Regression Analysis ◽  
Vacancy Formation Energy ◽  
Vacancy Formation ◽  
Kinetic Properties ◽  
Self Diffusion ◽  
Self Diffusion Coefficient

We investigated the relationship of the vacancy formation energy with kinematic viscosity and self-diffusion coefficient in liquid metals at the melting temperature. Formulas are obtained that relate experimental values of the vacancy formation energy, kinematic viscosity, and self-diffusion coefficient to the atomic size and mass, the melting and Debye temperatures. The viscosity and self-diffusion parameters are introduced. The ratio of these parameters to vacancy formation energy is equal to dimensionless constants. It is shown that the formulas for viscosity and self-diffusion differ only in dimensionless constants; the values of these constants are calculated. Linear regression analysis was carried out and formulas with the highest adjusted coefficient of determination were identified. The calculated values of the self-diffusion coefficient for a large number of liquid metals are presented.

High Temperature Diffusion of Oxygen in Chromite

2006 ◽  
Author(s):  
Stephen O’Toole ◽  
Nicholas Stevens
Keyword(s):  
Diffusion Coefficient ◽  
Oxygen Ions ◽  
Tetrahedral Sites ◽  
Temperature Diffusion ◽  
Experimental Trend ◽  
Linear Fit ◽  
The Mean ◽  
Diffusion Coefficient Of Oxygen ◽  
Arrhenius Expression ◽  
Made In

Molecular dynamics was used to calculate the diffusion coefficient of oxygen over a temperature range of 900–1700K. The chromite (FeCr2O4) system used consisted of 448 ions in a spinel structure. The spinel consisted of Fe2+ in tetrahedral sites and Cr3+ ions in octahedral sites surrounded by O2− ions. Schottky defects were made in the system by removing 10 oxygen ions, 4 iron ions and 4 chromium ions. The trajectory files from the simulations were examined for oxygen movement via a vacancy hopping mechanism and the mean-squared displacement of oxygen was plotted against time. A linear fit was performed to the plots and Einstein’s relationship was used to derive the diffusion coefficient from the gradient. The diffusion coefficients were then plotted against temperature and an Arrhenius expression was fitted to the trend and compared with the experimental trend calculated by Takada & Adachi.

Modeling the Diffusion Mechanism and the Reaction Kinetics for the Photocatalytic Degradation of Acid Red 151 Aqueous Solutions by ZnO: Comparison of Linear and Non-Linear Methods

2007 ◽  
Vol 10 (2) ◽  
Author(s):  
K. Vasanth Kumar ◽  
K. Porkodi
Keyword(s):  
Aqueous Solution ◽  
Diffusion Coefficient ◽  
Aqueous Solutions ◽  
Photocatalytic Degradation ◽  
Reaction Kinetics ◽  
Diffusion Mechanism ◽  
Batch Processes ◽  
Average Diffusion Coefficient ◽  
Diffusion Controlled ◽  
Average Diffusion

AbstractBatch processes were carried out for the photocatalytic degradation of Acid Red 151 from its aqueous solution using ZnO catalyst at different initial dye concentrations. The process was found to be diffusion controlled for the first 15-20 minutes (before irradiation) with an average diffusion coefficient of 6.759 × 10

scholarly journals The Kinetics of Joined Action of Triplet-Triplet Annihilation and First-Order Decay of Molecules in T1State in the Case of Nondominant First-Order Process: The Kinetic Model in the Case of Spatially Periodic Excitation

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Paweł Borowicz ◽  
Bernhard Nickel
Keyword(s):  
Diffusion Coefficient ◽  
Kinetic Model ◽  
Periodic Pattern ◽  
Constructive Interference ◽  
First Order ◽  
Dependent Rate ◽  
Diffusion Controlled ◽  
Spatially Periodic ◽  
Kinetics Of ◽  
Triplet Triplet Annihilation

In this paper the model developed for estimation of the diffusion coefficient of the molecules in the triplet state is presented. The model is based on the intuitive modification of the Smoluchowski equation for the time-dependent rate parameter. Since the sample is irradiated with the spatially periodic pattern nonexponential effects can be expected in the areas of the constructive interference of the exciting laser beams. This nonexponential effects introduce changes in the observed kinetics of the diffusion-controlled triplet-triplet annihilation. Due to irradiation with so-called long excitation pulse these non-exponential effects are very weak, so they can be described with introducing very simple correction to the kinetic model described in the first paper of this series. The values of diffusion coefficient of anthracene are used to calculate the annihilation radius from the data for spatially homogeneous excitation.

Cooling Design for the Next Generation Optical Disc Drive

2007 ◽  
Author(s):  
Takayuki Fujimoto ◽  
Nobuyuki Isoshima ◽  
Hiroyuki Toyoda ◽  
Yoshiaki Yamauchi ◽  
Hitoshi Matsushima ◽  
...  
Keyword(s):  
Transfer Rate ◽  
Data Transfer ◽  
Rotation Speed ◽  
Cooling System ◽  
Memory Capacity ◽  
Next Generation ◽  
Optical Disc ◽  
Data Transfer Rate ◽  
Disc Rotation ◽  
Disc Rotation Speed

Recently, the data transfer rate and the memory capacity of optical disc drives have been increasing dramatically. To obtain the high data transfer rate and greater memory capacity, the disc rotation speed and the laser power also need to be increased and these cause an increase in the temperature of the laser diode. Therefore, to develop the next generation optical disc drives, an enhanced cooling system is indispensable for the optical pick-up unit that contains the laser diode. As the temperature of the pick-up unit is influenced by the inside air flow induced by the disc rotation, it is quite necessary to grasp the velocity and temperature distribution inside the drive, and also the influence of the disc rotation speed on the temperature of the pick-up unit. Hence we applied PIV measurements and CFD simulations to visualize the flow field and the internal temperature. Then, during the actual disc recording process we measured the temperature of the pick-up unit and the internal air of the drive. As a result, we made clear the dependence of the disc rotation speed on the pick-up unit temperature. In addition, as an example for next generation optical disc drives, we evaluated the cooling system applying a small axial fan inside the drive and confirmed the validity of this fan system.

Nanoparticles Size in Fe73.5Cu1Mo3Si13.5B9 Melt

2020 ◽  
Vol 861 ◽  
pp. 107-112
Author(s):  
Vladimir S. Tsepelev ◽  
Yuri N. Starodubtsev ◽  
Kai Ming Wu ◽  
Yekaterina A. Kochetkova
Keyword(s):  
Experimental Data ◽  
Diffusion Coefficient ◽  
Critical Temperature ◽  
Temperature Dependence ◽  
Kinematic Viscosity ◽  
Arrhenius Equation ◽  
Reaction Rates ◽  
Mechanical Theory ◽  
Statistical Mechanical ◽  
Absolute Reaction

The size of the nanoparticles participating in the viscous flow and the diffusion coefficient were calculated using statistical mechanical theory of absolute reaction rates and the Arrhenius equation. As experimental data, temperature dependence of the kinematic viscosity and density of Fe73.5Cu1Mo3Si13.5B9 melt was used. At a temperature of 1600 K, after the melt is overheated above the critical temperature Tk = 1770 K, the nanoparticles size decreases from 0.92 to 0.47 nm, and the diffusion coefficient increases from 2.4·10-10 to 4.5·10-10 m2·s-1.

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