scholarly journals Theoretical description of the ligand function for ionoselective electrodes reversible to metal anion complexes. 3. Modeling of the electrode response in ligand and foreign ions solutions using the multi-species approach model

2021 ◽  
pp. 36-49
Author(s):  
Vladimir V. Egorov ◽  
Andrei V. Siamionau ◽  
Andrei D. Novakovskii ◽  
Yauhen B. Akayeu
Keyword(s):  
Phase Boundary ◽  
Chloride Concentration ◽  
Theoretical Description ◽  
Formation Processes ◽  
Adequate Description ◽  
Selective Electrode ◽  
Electrode Function ◽  
Foreign Ions ◽  
Diffusion Controlled ◽  
Diffusion Flows

A description for the ligand function of the tetrathiocyanatozincate selective electrode, has been proposed, using a multi-species approach model. This model takes into account simultaneous phase-boundary, diffusion-controlled, processes of ion exchange between tetrathiocyanatozincate, thyocyanate and foreign ions unable to form zinc complexes, as well as distribution of the neutral zinc complex between phases, partial decomposition of quaternary ammonium tetrathiocyanatozincate salt and stepwise complex formation processes in water phase. The model is based on solving the system of equations describing several interphase and intraphase equilibria, assuming that diffusion flows of all membrane and solution components at the phase boundary are stationary. It provides the adequate description of tetrathiocyanatozincate selective electrode in solutions of the ligand, foreign ions and mixed solutions of the above, and predicts the effect of zinc chloride concentration in the sample solution upon electrode function slopes, lower detection limits and selectivity coefficients.

Influence of cobalt chloride concentration on the selectivity of a tetrathiocyanocobaltate-selective electrode to thiocyanate

2013 ◽  
Vol 69 (1) ◽  
pp. 31-35
Author(s):  
E. M. Rakhman’ko ◽  
Yu. V. Matveichuk ◽  
L. S. Stanishevskii ◽  
V. V. Yasinetskii
Keyword(s):  
Cobalt Chloride ◽  
Chloride Concentration ◽  
Selective Electrode

Essay on Techniques & Physics of Some Diffusion-Controlled Processes in Materials: Relevance to Nanofabrication Applications

2009 ◽  
Vol 289-292 ◽  
pp. 679-686 ◽  
Author(s):  
Yuriy S. Nechaev ◽  
Andreas Öchsner
Keyword(s):  
Data Analysis ◽  
Data Interpretation ◽  
Original Data ◽  
Formation Processes ◽  
Controlled Processes ◽  
Oxidation Processes ◽  
Diffusion Controlled ◽  
Titanium Zirconium ◽  
The Given ◽  
First Time

An annotated analytical essay of possible nanofabrication and nanotechnology applications is presented with respect to: (1) some techniques and original results [1-4] concerning the regularities and micromechanisms (physics) of the hydrogen fluoride gas activator influence on the diffusion-controlled oxidation processes of titanium, zirconium and zirconium-based alloys with niobium, and also – on nitriding, boriding and carbiding a series of refractory metals (Ti, Zr, Nb, Mo, W, Ta); (2) some techniques, original results and physics of the diffusion-controlled formation processes of the compound-like nanosegregation [5-13] and the results [13-23] on the liquid-like phase at grain boundary regions in metals and alloys. In the scope of this review, a constructive analysis, the Arrhenius-type treatment, and the original data interpretation [16-21] has been carried out for the first time; (3) some techniques, original analytical results, and physics [24, 25] of the diffusion-controlled processes of the hydrogen multilayer intercalation (physisorption of a condensation or clustering type) with carbonaceous nanostructures. The main objective of the given analytical essay is to attract the researchers’ attention to the expediency of such a non-conventional data analysis and interpretation.

Precursor and processing effects on BaPbO3 formation kinetics

2006 ◽  
Vol 21 (3) ◽  
pp. 584-596 ◽  
Author(s):  
Jun-ichi Tani ◽  
Guerman Popov ◽  
Paul R. Mort ◽  
Richard E. Riman
Keyword(s):  
Phase Boundary ◽  
Reaction Temperature ◽  
Formation Rate ◽  
Exothermic Reaction ◽  
Three Dimensional ◽  
Interface Reaction ◽  
Diffusion Controlled ◽  
Wide Range ◽  
Lead Oxides ◽  
Nitrate System

The synthesis of BaPbO3 from a wide range of mixtures containing metalorganic precursors, nitrate precursors, lead oxides, barium oxide and peroxide was investigated, and the kinetics was analyzed using the Johnson–Mehl–Avrami (JMA) equation. It was found that Ba and Pb stearate soaps and Pb oxalate that were used as metalorganic precursors formed BaCO3 and PbO or Pb3O4 after firing at 440 °C. The formation rate of BaPbO3 from a metalorganic precursor system is not higher than that from the conventional BaCO3–PbO system and does not depend on mixing methods or the kinds of metalorganic precursors but instead on the synthesis atmosphere. In the case of the BaCO3–PbO system, the Avrami exponent (n) is ∼1, indicating that the reaction is controlled by the phase-boundary-contraction interface reaction. For the BaO2–PbO2 system, n has two values ∼1 and ∼0.3, depending on the reaction temperature and time, indicating that the reaction is either controlled by the phase-boundary-contraction interface reaction or diffusion-controlled reaction. In the Ba nitrate–Pb nitrate system, phase-pure BaPbO3 is obtained at 550 °C, which is 250 °C lower than in the case of the BaCO3–PbO system. The value of n for the nitrate system is ∼1.5, indicating that the reaction is controlled by a three-dimensional (3D) diffusion-controlled nucleation mechanism. In the BaO–PbO system, the formation of BaPbO3 started at 350 °C by an exothermic reaction and the content of BaPbO3 in the product was ∼40 wt%, which is independent of reaction temperature as well as time in the temperature range of 350–500 °C.

scholarly journals Obtaining food dyes of the anthocyanin class from grape pomace: the mechanism of the extraction process

2020 ◽  
pp. 134-141
Author(s):  
M.V. Nikolenko ◽  
◽  
K.O. Elchaninova ◽  
V.O. Karabut ◽  
O.Yu. Vashkevych ◽  
...  
Keyword(s):  
Experimental Data ◽  
Raw Materials ◽  
Diffusion Mechanism ◽  
Extraction Process ◽  
Theoretical Description ◽  
Grape Pomace ◽  
Solution Temperature ◽  
Diffusion Controlled ◽  
Heterogeneous Processes ◽  
Limiting Stage

In order to determine the mechanism and factors of optimization of the process of extraction of anthocyanin dyes from crushed grape pomace, the kinetics of the process at the temperatures of 14 and 800C was studied using aqueous and aqueous-ethanolic solutions under conditions of intensive mixing. For the theoretical description of the kinetic data, a model of the extraction process from a porous solid body was used under conditions of relatively small values of constrained diffusion coefficients. It was established that the experimental data are well described by the equation for the internal diffusion mechanism of the extraction process. It was shown that the experimental data are also well described by the Yander equation proposed for modeling diffusion-controlled heterogeneous processes with constant parameters of the diffusion. It was concluded that both equations are similar to each other and differ only in the coefficients at the degrees of transformation, which is due to the assumptions that were made in their derivation. The conclusion about the nature of the limiting stage of the process of extraction of anthocyanin dyes was confirmed by calculations of the apparent activation energy, the value of which was 14.0 kJ mol–1. The obtained data allowed determining the factors of optimization of anthocyanin extraction process from grape pomace: particle size of raw materials, anthocyanin concentration in solution, temperature, ethanol content in solution, solution acidity, degree of plant cell destruction and ultrasonic treatment.

scholarly journals The theoretical description for the electrochemical determination of 4-4´-dihydroxyazobenzene, assisted by a composite of squaraine dye with cobalt (iii) oxyhydroxide in pair with cobalt (iv) oxide

2020 ◽  
Vol 10 (6) ◽  
pp. 619
Author(s):  
Volodymyr Valentynovych Tkach ◽  
Marta V. Kushnir ◽  
Oleksandra V. Ahafonova ◽  
Mariia P. Mytchenok ◽  
Andrii V. Bocharov ◽  
...  
Keyword(s):  
Double Electric Layer ◽  
Electrochemical Determination ◽  
Theoretical Description ◽  
The Other ◽  
System A ◽  
Diffusion Controlled ◽  
Squaraine Dye ◽  
Efficient Diffusion ◽  
Biological Liquids

<p>The theoretical description for 4-4´-dihydroxyazobenzene CoO(OH) – assisted electrochemical determination in the mushroom pulp, food, and biological liquids has been described. In this system, a squaraine dye is used as a Cobalt(III)oxyhydroxide stabilizer and electron transfer mediator. It is shown that, contrary to the large part of the systems with cobalt (III) oxyhydroxide, this system will behave more stably, providing an efficient diffusion-controlled process. On the other hand, the oscillatory and monotonic instabilities, although possible, are caused by the double electric layer influences of either chemical or electrochemical stage.</p>

scholarly journals Spurious Hyperchloremia and Negative Anion Gap in a Child with Refractory Epilepsy

2016 ◽  
Vol 2016 ◽  
pp. 1-3
Author(s):  
Madhuradhar Chegondi ◽  
Balagangadhar R. Totapally
Keyword(s):  
Refractory Epilepsy ◽  
Chloride Concentration ◽  
Blood Chemistry ◽  
Anion Gap ◽  
Selective Electrode ◽  
Chloride Level ◽  
Plasma Chloride ◽  
Electrode Method ◽  
High Chloride ◽  
Negative Anion Gap

We report a case with spurious hyperchloremia with negative anion gap in a child who was taking potassium bromide for refractory epilepsy. Blood chemistry showed a high chloride level (171 mEq/L) and a negative anion gap (−52 mEq/L). Plasma chloride concentration is measured by an ion-selective electrode method; however the presence of other anions like bromide and iodides can interfere with chloride level and largely overestimates the chloride concentration. Thus hyperchloremia with a negative anion gap is a clue to the diagnosis of halides like bromide and iodide ingestion.

Sign in / Sign up

Export Citation Format

Share Document