Kinetic Investigation of the Corrosion Process by Means of the b Rays Absorption

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Alexandru Cecal ◽  
Florica Ionic� ◽  
Karin Popa
Keyword(s):  
Experimental Data ◽  
Corrosion Process ◽  
Kinetic Investigation ◽  
Iron Ions ◽  
Metal Sample ◽  
Steel Composition ◽  
Corrosive Solution ◽  
Corrosion Medium ◽  
Global Rate ◽  
Complex Process

This paper deals with an approach of the investigation of the corrosion reactions, which is based on the absorption of b rays emitted by Tl-204 radionuclide by the iron ions, which pass into the aggressive solution through anodic dissolution of a metal sample. There can be noticed a decreassing of the activity b rays, reduction which is measured while the concentration of the iron ions in the corrosive solution increases. Out of the experimental data, there can be calculated the constant of the global corrosion rate, which accurately characterizes the development of this complex process. There was experimentally investigated the corrosion of three types of steel: H-12, MoCN-15 and W-85 in aggressive media of HCl and NaCl solutions.The values of the global rate constants vary depending on the steel composition and the corrosion medium.

scholarly journals Study of the inhibitory ability of inorganic di- and polyphosphate compositions

2020 ◽  
Vol 315 ◽  
pp. 04002
Author(s):  
Aktoty Niyazbekova ◽  
Timur Shakirov ◽  
Mayra Almagambetova
Keyword(s):  
Experimental Data ◽  
Kinetic Data ◽  
Research Work ◽  
Corrosion Process ◽  
Degree Of Protection ◽  
Inhibitory Ability ◽  
Depth Index ◽  
Corrosion Deposits ◽  
The Stability ◽  
Quantitative Indicators

The article considers the anticorrosive properties of inorganic di-and polyphosphate compositions in relation to St-3 steel, depending on the pH of the medium, the nature and concentration of phosphate, and the nature of the modifier ion. The research was conducted using GOST-based methods: gravimetry, potentiometry, photocolorimetry, infrared spectroscopy and scanning electron microscopy. On the basis of experimental data, quantitative indicators of corrosion process were determined: the rate of corrosion process, the degree of protection, the depth index, the coefficient of inhibition and the assessment of the stability of the formed film on the ball scale of corrosion resistance against steel. The analysis of experimental data allows to establish the influence of the above factors on the corrosion processes in the systems under study. The experimental data are supplemented by thermodynamic calculations of the corrosion process parameters, the results of which correlate well with the kinetic data of the process under study. In the course of the research work, the analysis of corrosion deposits was also carried out. The regularities established during the work contribute to the creation of effective di-and polyphosphate inhibitors with the highest degrees of protection.

Mossbauer Investigation of the Chelyabinsk Meteorite Fragment

2016 ◽  
Vol 845 ◽  
pp. 269-272
Author(s):  
Magomed Guseynov ◽  
Sergey Taskaev ◽  
Ibragimkhan Kamilov
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Effective Magnetic Field ◽  
Iron Ions ◽  
Qualitative Explanation ◽  
Chelyabinsk Meteorite ◽  
Chemical Conditions ◽  
The Individual ◽  
Physical And Chemical ◽  
Quadruple Splitting

The article devoted to study of the fragments of Chelyabinsk meteorite with the help of Mossbauer spectroscopy. It is shown that the iron in various fragments of the meteorite exist in different crystallographic, physical and chemical conditions. A new phenomenon of sharp increasing effective magnetic field in the region of the iron nuclei in the temperature range of 553-573 К and jumps of the main parameters of Mossbauer spectra at other temperatures are observed. According to the data of the isomer shifts and quadruple splitting of the individual spectra, iron ions have a valence of Fe2+ − 3d6, Fe3+ − 3d5, Fe4+ − 3d4, Fe6+ − 3d2 and also intermediate between them. A qualitative explanation of the experimental data is proposed.

scholarly journals Scientific insights of electrochemical replacement approach to describe the origin of Pre-Columbian Peruvian gilded copper-based objects

2021 ◽  
Vol 2118 (1) ◽  
pp. 012015
Author(s):  
A Alviz-Meza ◽  
D A Chipoco Haro ◽  
M I Velarde
Keyword(s):  
Experimental Data ◽  
Quantitative Data ◽  
Gold Film ◽  
Corrosion Process ◽  
Conservation Strategies ◽  
Cultural Groups ◽  
Electrolytic Solution ◽  
Deterioration Rate ◽  
Gold Precursor ◽  
Replacement Technique

Abstract Pre-Columbian Peruvian goldsmiths developed gilded copper-based objects by ancient techniques that require identification to propose conservation strategies. Lechtman H, conducted experiments to suggest that the electrochemical replacement was the gilding technique used by the Moche and Vicus cultural groups. Despite her remarkable achievement, the quantitative data provided by her is still open to discussion. This work focused on obtaining experimental data to recreate her protocol by introducing less gold precursor. Polished copper pieces were plated with an adherent gold film of up to 7.5 µm after immersing them into an electrolytic solution for 3 min and 6 min at 80 °C. Our results demonstrated that the electrochemical replacement technique gives rise to anodic regions in the plated objects. Further studies around the corrosion process that undergoes these heritage objects in burial and environmental conditions are suggested to determine their deterioration rate. Moreover, electroless and galvanic techniques should be explored in order to improve current approaches.

Bubble model analysis on the cell formation of a green alga

2020 ◽  
Vol 13 (05) ◽  
pp. 2050032
Author(s):  
Yuandi Wang ◽  
Nanjun Yan ◽  
Zhigang Zhou ◽  
Kai Zeng
Keyword(s):  
Differential Equation ◽  
Experimental Data ◽  
Cell Walls ◽  
Morphological Evolution ◽  
Cell Formation ◽  
Biological Mechanisms ◽  
Double Bubble ◽  
Complex Process ◽  
Differential Equation Models ◽  
Experimental Data Analysis

Mathematical simulation for cell and division, a complex process resulting from a series of major morphological evolution and biological mechanisms, is shown by using variational principle. Groups of differential equation systems with boundary conditions for the cell walls satisfying come out from analysis on minimally total length. Double bubble model for cell geometric formation is found and a mechanism for tri-bubble model is also investigated here. An interesting fact is that every angle between any two tangent lines at the same intersections of cell edges for both double bubble and tri-bubble is equal to [Formula: see text]. In addition to the derivation of these differential equation models, these theories are also applied to the specific experimental data analysis, and it is found that the model is very consistent with the experimental results.

Interplay of Soret vs. Normal Impurity Diffusion During Laser or E-Beam Induced Heat Flow Transients in Metals

1981 ◽  
Vol 4 ◽  
Author(s):  
L.F. Dona' Dalle Rose ◽  
A. Miotello
Keyword(s):  
Experimental Data ◽  
Electron Beam ◽  
Heat Flow ◽  
Diffusion Processes ◽  
Soret Effect ◽  
Energy Sources ◽  
Metal Sample ◽  
Short Pulses ◽  
Thermal Transient ◽  
Very Short Pulses

ABSTRACTIn the growing amount of the experimental data on the diffu sion processes of implanted impurities in a metal sample irradiated by highly energetic and very short pulses, some order may be introduced by the knowledge of the structure of induced thermal transient. The differences in such a structure due to two different energy sources (laser and electron beam) are de scribed with reference to the conditions under which Soret diffusion may be experimentally observed as distinct from nor mal diffusion. Laser induced transient seem to offer this possibility.Some previously reported diffusion processes in laser irra diated systems are reinterpreted on this basis, showing the importance of the Soret effect.

scholarly journals The process of phagocytosis in the antigenic load and their correction

2014 ◽  
Vol 18 (3 (71)) ◽  
Author(s):  
B. M. Verveha
Keyword(s):  
Experimental Data ◽  
Immune Complex ◽  
Neutrophilic Granulocytes ◽  
Complex Process ◽  
Antigenic Load

Using experimental data an analysis of the changes of the oxygen-dependent and oxygen independent enzymatic processes in neutrophilic granulocytes of rats that had simulated chronic immune complex process with placental polybiolinum correction has been carried out. It was established, that under conditions of chronic immune complex process enzymatic processes in neutrophilic granulocytes get activated. Application of placental polybiolinum restored grasping ability of neutrophils and reduced the activity of the oxygen-dependent and oxygen independent enzymatic processes in neutrophilic granulocytes, which in turn leads to the normalization of the integration processes.

MAGNETIC BEHAVIOR OF LEAD-BISMUTATE GLASSES CONTAINING TRANSITION METAL ELEMENTS

2001 ◽  
Vol 15 (27) ◽  
pp. 1231-1236 ◽  
Author(s):  
R. POP ◽  
V. SIMON ◽  
I. COSMA ◽  
M. COLDEA
Keyword(s):  
Experimental Data ◽  
Magnetic Susceptibility ◽  
Transition Metal ◽  
Transition Metal Oxides ◽  
Glass Matrix ◽  
Magnetic Behavior ◽  
Magnetic Interaction ◽  
Iron Ions ◽  
Manganese Ions ◽  
Curie Temperatures

The investigated samples are obtained by adding to the 3Bi2O3·2PbO glass matrix the transition metal oxides Fe2O3 or MnO up to 20 mol%. The temperature dependencies of the magnetic susceptibility evidence negative paramagnetic Curie temperatures suggesting the antiferromagnetic nature of the magnetic interaction between the transition metal (TM) ions in the samples studied. According to the magnetic moment values, calculated from the experimental data, the valence state of the iron ions changes from Fe 3+ to Fe 2+ and that of manganese ions from Mn 2+ to Mn 3+ as the concentration x increases from 1 to 20 mol%.

Kinetics and mechanism of the aminolysis of thioesters and thiocarbonates in solution

2009 ◽  
Vol 81 (4) ◽  
pp. 685-696 ◽  
Author(s):  
Enrique A. Castro
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Rate Constant ◽  
Aqueous Ethanol ◽  
Kinetics And Mechanism ◽  
Kinetic Investigation ◽  
Concerted Mechanism ◽  
Tetrahedral Intermediate ◽  
Leaving Group ◽  
The Stability

The aminolysis reactions of thioesters and thiocarbonates, in either aqueous solution or in 44 wt % aqueous ethanol at 25 °C, are subjected to a kinetic investigation. The Brønsted-type plots (lg kN vs. amine pKa, where kN is the nucleophilic rate constant) obtained for these reactions can be grouped in three categories: linear plots with slopes 0.8-1, biphasic plots (two linear portions and a curve in between), and linear plots with slopes 0.4-0.6. The two former plots are attributed to stepwise reactions through a zwitterionic tetrahedral intermediate. The latter plots are associated with a concerted mechanism. The fact that some reactions are stepwise and others concerted depends on the stability of the zwitterionic tetrahedral intermediate. This work shows how the experimental data allows one to assess the mechanism of these reactions. Also discussed are the factors that affect the stability of this intermediate, which in turn determines the pathway followed by the reaction. The factors analyzed in this work are (i) the leaving group of the substrate, (ii) the nature of the amine, (iii) the non-leaving group of the substrate, (iv) the electrophilic group of the substrate (CS vs. CO), and (v) the solvent.

On Bainite Transformation Kinetics and Mechanism

2007 ◽  
Vol 539-543 ◽  
pp. 3018-3023 ◽  
Author(s):  
Si Xin Zhao ◽  
Wei Wang ◽  
Da Li Mao
Keyword(s):  
Experimental Data ◽  
Growth Rates ◽  
Bainitic Ferrite ◽  
Transformation Kinetics ◽  
Alloying Element ◽  
Transformation Mechanism ◽  
Bainite Transformation ◽  
Steel Composition ◽  
Slowing Down ◽  
Theoretical Results

The platelike bainitic ferrite growth rates were calculated by two modified diffusional models. Good agreements between experimental and theoretical results are found in Fe-0.59C wt.%, Fe-0.81C wt.% and Fe-0.478C-4.87Ni wt.% alloys. A slowing down effect due to the alloying element Mo is emphasized in Fe-0.69C-1.8Ni-0.8Mo wt.% alloy. However, the experimental data are lower than theoretical ones about two orders in Fe-C-8.7Ni wt.% alloys. According to the discussion of the results, it is suggested that the bainite transformation mechanism may relates to steel composition and transformation temperature.

A Simple Modelling Method for Deflection of Circular Plates Under Impulsive Loading using Dimensionless Analysis and Singular value Decomposition

2010 ◽  
Vol 26 (3) ◽  
pp. 355-361 ◽  
Author(s):  
H. Gharababaei ◽  
N. Nariman-zadeh ◽  
A. Darvizeh
Keyword(s):  
Experimental Data ◽  
Singular Value Decomposition ◽  
Impulsive Loading ◽  
Singular Value ◽  
Circular Plates ◽  
Dimensionless Analysis ◽  
Novel Approach ◽  
Complex Process ◽  
Value Decomposition ◽  
Svd Method

AbstractA novel approach of numerical modelling using input-output experimental data pairs is presented for deflection-thickness ratio of circular plates subjected to impulse loading. In this way, singular value decomposition (SVD) method is used in conjunction with dimensionless parameters incorporated in such complex process. The closed-form obtained model shows very good agreement with some testing experimental data pairs which have been unforeseen during the training process. Moreover, two modifications are consequently suggested for some similar models already proposed in previous works. The approach of this paper can generally be applied to model very complex real-world processes using appropriate experimental data.

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