Studies on Liesegang rings of cobalt hydroxide in 1% agar gel medium

Rajurkar, N. S.; Ambekar, B.R.

doi:10.1016/j.molliq.2015.01.042

Cited by 10 publications

(17 citation statements)

References 13 publications

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“…The Liesegang bands formed in a gel due to the reaction CoCl 2 + 2NH 4 OH → Co(OH) 2 + 2NH 4 Cl have been studied extensively with well-established spatio-temporal characteristics. , To validate the RGB value method, we have also performed few experiments on this system. The photograph of this system is shown at the top of Figure A.…”

Section: Resultsmentioning

confidence: 99%

Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Walimbe¹,

Takale²,

Kulkarni

et al. 2021

Langmuir

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In the present study, a method is described for precise determination of spatial characteristics of Liesegang bands formed by employing a classical 1D setup using a web-based free resource (). The method involves the compartmentalization of the information on each pixel into R (red), G (green), or B (blue) values from the pattern images obtained using a simple digital camera. The values can further be converted to absorbance values by using the system blank. Each trough (or peak) in the graph of RGB values (or absorbance values) corresponds to a band in the pattern. The method is employed to determine the spacing and width of the periodically precipitating AgCl, AgBr, and Co(OH)2 in an agar gel. It is observed that AgCl shows revert banding, and AgBr shows revert banding at the top of the tube and then diverges to regular banding at the bottom of the tube, whereas the Co(OH)2 patterns explicitly show regular banding under given experimental conditions. It is also observed that minute instabilities, such as the formation of secondary bands, can also be visualized by the present method.

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Section: Resultsmentioning

confidence: 99%

Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Walimbe¹,

Takale²,

Kulkarni

et al. 2021

Langmuir

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“…Several researchers have studied this phenomenon in minerals (Kulkarni S.D. et al, 2017, Rajurkar N. et al, 2015, George J. et al, 2005and George J. et al, 2003 but in metals this phenomenon has not been studied so far.…”

Section: Methodsmentioning

confidence: 99%

Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors

Khan¹,

Bong²,

Rigit³

et al. 2018

IJET

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Overhead high voltage transmission conductors used worldwide are produced in several configurations. A multi-strand conductor of the type ACSR330 is typically used for 275 kV overhead transmission lines. The conductor is composed of 7 inner strands of Ultra High Strength Galvanized Steel for the mechanical support of the conductor and 26 strands of high conductivity Aluminum wires meant for power transfer over long distances. During the use, weather conditions and power fluctuations tend to degrade the properties of these conductors. In the present work, study of the state of galvanization and oxidation of an ACSR330 conductor is undertaken with a view to understand the effectiveness of the loss in corrosion protection and changes in the zinc coating on the galvanized steel strands after use for 25 to 30 years. The Scanning Electron Microscopy (SEM), X Ray Diffraction (XRD) and Energy Dispersive Analysis through X rays (EDAX) provide a very useful insight into the state of the conductor and gives important information to the strategic decision maker, whether or not to replace the conductor. It was observed in the present study that the zinc coating diffuses inside the steel strand under temperature and time effect. This unique study on the used conductors also reveals that the morphology of the coating and its interface structure changes significantly compared to an unused conductor of the same age.

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“…9,10,12,17 When periodic precipitation is carried out in a chemically inert hydrogel medium, especially with a high polymer concentration, the effect is exerted by the viscosity and density of this medium, leading to a slower mass transfer process and, accordingly, a decreased diffusion coefficient of the reactants, although not very significant. The decimal order of magnitude of the diffusion coefficient of carbonates, acetates, nitrates, chromates, and chlorides in the precipitation reaction in the agar-agar, gelatin, or silica medium is within 10 −10 −10 −9 m 2 / s. 3,16 These values are almost three orders of magnitude higher than the characteristic values of the diffusion coefficient of spherical colloidal particles, low-molecular-weight substances in a polymer matrix, and macromolecules in solution. For example, the order of the diffusion coefficient of water in the solid phase of chitosan of its basic and salt forms is 10 −12 − 10 −11 and 10 −13 −10 −12 m 2 /s, respectively, 18,19 and that of (self) diffusion of chitosan macromolecules in CH 3 COOH and HCl without and with the addition of CH 3 COONa, NaCl, and KCl is 10 −11 −10 −10 m 2 /s.…”

Section: ■ Introductionmentioning

confidence: 92%

Formation of Liesegang Structures under the Conditions of the Spatiotemporal Reaction of Polymer-Analogous Transformation (Salt → Base) of Chitosan

et al. 2020

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This paper presents the results of our study of the diffusion front progression of OH − ions in the bulk of a flat layer of the salt chitosan form during the course of the chemical reaction of the polymer-analogous salt → base transformation, accompanied by the formation of a water-insoluble polymeric phase as a gel film with its structure of concentric rings or tangential bands. Using scanning electron microscopy and polarization microscopy, structural and morphological features of these periodic formations were visualized. Physicochemical parameters and spatiotemporal mass transfer characteristics were obtained. The process under study is shown to obey the classical laws of ion-exchange reactions, and the formation kinetics and the ratio of the positions of periodic structures are described by the laws characteristic of the Liesegang phenomenon. The average diffusion coefficients of hydroxide ions in the periodic formations calculated, considering the protonation degree of amino groups, were found to be no more than a decimal order of magnitude lower than those in an aqueous solution. This confirms the fact of swelling of the formed chitosan base and the existence of a gel film, in whose liquid phase diffusion occurs.

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Studies on Liesegang rings of cobalt hydroxide in 1% agar gel medium

Cited by 10 publications

References 13 publications

Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Precise Evaluation of Spatial Characteristics of Periodically Precipitating Systems via Measurement of RGB (Red, Green, and Blue) Values of Pattern Images

Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors

Formation of Liesegang Structures under the Conditions of the Spatiotemporal Reaction of Polymer-Analogous Transformation (Salt → Base) of Chitosan

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