B N GHOSH

K C RAY

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Nature

The apparent electrokinetic potential ζa of tin sulphide sol has been measured both by electro-osmotic and electrophoretic methods in the region of slow coagulation using Smoluchowski's equation in the presence of equicoagulating concentrations of electrolytes containing counter-ions of different valency. From the apparent values of ζa the true ζ was found by applying surface conductance correction using the equation 1/ζa=1/ζa+m·1/S where m is a constant involving specific surface conductance and S the specific conductance in bulk of the solution in contact with the colloid particles. The results lead to the conclusion that a given rate of coagulation of the tin sulphide sol by different electrolytes is characterised by a definite value of the true ζ-potential, independent of the valency of the counter-ions used. The average value of true ζ-potential of the particles of the sol determined by the electrophoretic and electro-osmotic methods is equal to 29.6 m.v. when the rate of coagulations is slow (20 hours). © 1958 Dr. Dietrich Steinkopff Verlag.

Kolloid-Zeitschrift

Studies on coagulation and electrokinetic potential of tin sulphide sol

A thoroughly purified thorium oxide sol (sol-I) has been prepared by continued dialysis for about three months. The electrokinetic potential of this sol for a given slow rate of coagulation has been measured by endosmotic as well as by electrophoretic methods. Correction due to surface conductance has been applied by using an equation of the form 1/ζα=1 ζ+m 1/S. The true ζ-potential for rapid rate of coagulation obtained from endosmosis has been found to be slightly less than that obtained for the slow rate. Hence it is concluded that there exists a critical zone of true ζ-potential for coagulation of this sol. All these data lead to the conclusion that a given rate of coagulation is characterised by a definite value of true ζ-potential. © 1958 Dr. Dietrich Steinkopff Verlag.

Stability and electrokinetic potential of thorium oxide sol (part I)

The electrokinetic velocities of ferric-ferrocyanide sol for a given slow rate of coagulation by electrolytes have been measured both by the electro-osmotic and electrophoretic methods. From these data the values of true ζ potential have been found by graphical extrapolation based on the equation 1/ζa = 1/ζ + m 1/S, where ζa represents the electrokinetic potential calculated from Smoluchowski equation, S the bulk specific conductivity of the intermicellar fluid and m is a constant under the experimental conditions and includes the specific surface conductance of the sol particles. The values of the true ζ thus found from the electro-osmotic and electrophoretic data agree well with each other. The results lead to the further conclusion that a given rate of coagulation of the sol is characterized by a definite value of the true ζ-potential independent of the valency of the counter-ions used.

Journal	Nature
Publisher	-
ISSN	0028-0836