scholarly journals Theory of staircase cyclic voltammetry of two electrode reactions coupled by a chemical reaction

2019 ◽  
Vol 51 (3) ◽  
pp. 348-357
Author(s):  
Š. Komorsky-Lovrić ◽  
M. Lovrić
Keyword(s):  
Cyclic Voltammetry ◽  
Chemical Reaction ◽  
Forward Rate ◽  
Electrode Reactions ◽  
Reversible Chemical Reaction ◽  
Ece Mechanism ◽  
Forward Rate Constant ◽  
Thermodynamic And Kinetic Parameters ◽  
The Stability ◽  
Kinetics Of

Two reversible electrode reactions that are connected by either reversible or totally irreversible chemical reactions are theoretically analysed by staircase cyclic voltammetry. The dependence of peak potentials on the thermodynamic and kinetic parameters is calculated. If the mechanism is permanently in equilibrium, the stability constant of the reversible chemical reaction can be determined. Furthermore, the critical kinetic parameter is determined and its application to the measurement of the forward rate constant of the chemical reaction is demonstrated. Also, the influence of the kinetics of electrode reactions is discussed. Keywords: ECE mechanism; Cyclic voltammetry; Theory

D- and T-optimum designs for the kinetics of a reversible chemical reaction

1998 ◽  
Vol 43 (1-2) ◽  
pp. 185-198 ◽  
Author(s):  
Anthony C. Atkinson ◽  
Barbara Bogacka ◽  
Mariusz B. Bogacki
Keyword(s):  
Chemical Reaction ◽  
Reversible Chemical Reaction ◽  
Kinetics Of

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

scholarly journals Forward Rate Bias in Developed and Developing Countries: More Risky Not Less Rational

Econometrics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 43
Author(s):  
Michael D. Goldberg ◽  
Olesia Kozlova ◽  
Deniz Ozabaci
Keyword(s):  
Developing Countries ◽  
Forward Rate ◽  
Currency Markets ◽  
Developed Country ◽  
Slope Coefficient ◽  
Break Points ◽  
Time Periods ◽  
The Stability ◽  
Widespread View ◽  
Shed Light

This paper examines the stability of the Bilson–Fama regression for a panel of 55 developed and developing countries. We find multiple break points for nearly every country in our panel. Subperiod estimates of the slope coefficient show a negative bias during some time periods and a positive bias during other time periods in nearly every country. The subperiod biases display two key patterns that shed light on the literature’s linear regression findings. The results point toward the importance of risk in currency markets. We find that risk is greater for developed country markets. The evidence undercuts the widespread view that currency returns are predictable or that developed country markets are less rational.

Modeling of sorption kinetics of U(VI) micro-quantities nanostructured materials with anatase mesoporous structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Veniamin Zheleznov ◽  
Aleksey Golikov ◽  
Tatiana Sokolnitskaya ◽  
Sergey Ivannikov
Keyword(s):  
Nanostructured Materials ◽  
Sorption Kinetics ◽  
Uranyl Ion ◽  
Competitive Sorption ◽  
Hydroxyl Groups ◽  
Complex Ions ◽  
The Stability ◽  
Kinetics Of ◽  
Mesoporous Structures ◽  
Ionic Forms

Abstract The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.

On the Role of Diffusion in the Oxidation of Fe, Ni, Co and the Fe-Sn Alloy by Calcium and Sodium Sulfates

2006 ◽  
Vol 258-260 ◽  
pp. 63-67
Author(s):  
V.M. Chumarev ◽  
V.P. Maryevich ◽  
V.A. Shashmurin
Keyword(s):  
Co Oxidation ◽  
Chemical Reaction ◽  
Diffusion Processes ◽  
Transport Processes ◽  
Diffusion Transport ◽  
Sodium Sulfates ◽  
Product Forms ◽  
Kinetics Of ◽  
Dominant Part

Diffusion processes play a dominant part in the macro kinetics of Fe, Ni and Co oxidation by calcium and sodium sulfates. Here, the reaction product forms a compact covering which spatially divides the reagents on the surface in the same way as in the oxidation and sulfidization of metals by oxygen and sulfur. Therefore, it is possible to assume in advance that interaction of metals with calcium and sodium sulfates will be determined not by the actual chemical reaction properly but by the diffusion transport processes.

scholarly journals Experimental Study on the Softening Characteristics of Sandstone and Mudstone in Relation to Moisture Content

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Gui-chen Li ◽  
Chong-chong Qi ◽  
Yuan-tian Sun ◽  
Xiao-lin Tang ◽  
Bao-quan Hou
Keyword(s):  
Moisture Content ◽  
Vertical Displacement ◽  
Surface Porosity ◽  
Shear Tests ◽  
Moisture Contents ◽  
Dynamic Finite Element ◽  
Rock Types ◽  
Underground Roadway ◽  
The Stability ◽  
Kinetics Of

The kinetics of fluid-solid coupling during immersion is an important topic of investigation in rock engineering. Two rock types, sandstone and mudstone, are selected in this work to study the correlation between the softening characteristics of the rocks and moisture content. This is achieved through detailed studies using scanning electron microscopy, shear tests, and evaluation of rock index properties during exposure to different moisture contents. An underground roadway excavation is simulated by dynamic finite element modeling to analyze the effect of moisture content on the stability of the roadway. The results show that moisture content has a significant effect on shear properties reduction of both sandstone and mudstone, which must thus be considered in mining or excavation processes. Specifically, it is found that the number, area, and diameter of micropores, as well as surface porosity, increase with increasing moisture content. Additionally, stress concentration is negatively correlated with moisture content, while the influenced area and vertical displacement are positively correlated with moisture content. These findings may provide useful input for the design of underground roadways.

Sign in / Sign up

Export Citation Format

Share Document