• K S Gururaja Doss

      Articles written in Proceedings – Section A

    • Erratum

      K S Gururaja Doss Basrur Sanjiva Rao

      More Details Fulltext PDF
    • Ageing of surfaces of solutions—I - The study of variation of surface tension of solutions with time by the ring method

      K S Gururaja Doss Basrur Sanjiva Rao

      More Details Fulltext PDF
    • Collision frequency in solutions

      K S Gururaja Doss

      More Details Abstract Fulltext PDF

      An interpretation of a collision in solution is given on the basis of Wheeler’s theory of liquids. The expression for the collision frequencies based on this theory work out to be similar to those got by other methods and which have been used with success in the interpretation of kinetics of reaction in solution.

    • Ageing of surfaces of solutions—II - Activated accumulation of solute molecules

      K S Gururaja Doss

      More Details Abstract Fulltext PDF

      A new application of the Langmuir-Adam surface pressure technique has been made in the study of ageing of surface of solutions. It is found that a fresh surface of a solution of benzopurpurin exhibits a fall of surface tension with time. If by suitable methods, an overcrowding (by solute molecules) of the surface is brought about, such a surface exhibits a rise of surface tension in time. The molecules accumulated at the surface are shown to exhibit a reluctance to get into solution; it has therefore been possible to measure the rate of accumulation and has been found to be very slow. The slowness is best accounted for on the basis of activated accumulation. The postulation of activation is further helpful in understanding (a) the time variation of surface tension, (b) the high temperature coefficient and (c) the manifestation of surface pressure. The results of the present investigation are extremely helpful in measuring the efficacy of a substance as the stabiliser of foam. Several new lines of investigation which have opened up are briefly indicated.

    • Inhibition of fluorescence

      K S Gururaja Doss

      More Details Abstract Fulltext PDF

      The data obtained by Jette and West regarding inhibition of fluorescence have been examined with a view to get at the mechanism of the inhibition process. The results show that inhibitions by ions such as Cl′, Br′, I′, etc., can be interpreted on the basis of collisions of the second kind. The auto-inhibition of fluorescence, however, as shown by a critical examination of fluoremetric data cannot be explained on the basis of collisions of the second kind; it is found necessary to postulate polymerisation of the fluorescent substance, in order to explain the self-inhibition of the ultraviolet fluorescence of quinine sulphate and aniline iodeosine solutions.

    • Selective adsorption on silica gel from pyridine-alcohol mixtures

      K S Gururaja Doss

      More Details Abstract Fulltext PDF

      Refractive indices of pyridine-ethyl alcohol mixtures have been measured at 23°·37 C. The selective adsorption on silica gel from pyridine-ethyl alcohol mixtures has been measured over the entire range of concentration. The selectivity concentration curve is found to be of the S-type. Evidence is adduced to show that an adsorption compound C5H5N, 2 EtOH is formed at the interface.

      In conclusion the authors wish to thank Professor B. Sanjiva Rao for his interest in the work.

    • A theory of contact angles

      K S Gururaja Doss Sanjiva Rao

      More Details Abstract Fulltext PDF

      A theory of contact angles has been developed. The phenomena at the interface between a solid and a liquid have been discussed on the basis of this theory.

    • Spreading coefficients of nekal BX solutions

      M R Bhimasena Rao K S Gururaja Doss

      More Details Abstract Fulltext PDF

      The spreading coefficients of paraffin oil on nekal BX solutions have been determined by the floating lens technique of Langmuir. These measurements combined with the surface tension of the aqueous solutions give an exact idea of the wetting characteristics of the solutions. A rough measure of the wetting power is shown to be given by a measurement of the surface tension of the aqueous solution.

      It is shown that small quantities of nekal BX greatly improve the spreading qualities of oils on polar surfaces.

      The spreading coefficients of nekal BX solutions are found to be negative even at the highest concentrations tried. It is therefore suggested that the wetting takes place by penetration and not by spreading. Thus, the adhesion tension of the aqueous solutions against oil gives a more correct measure of the wetting power.

    • Pulsations on mercury surface caused by polarisation

      K S Gururaja Doss Basrur Sanjiva Rao

      More Details Fulltext PDF
    • Effect of electric field on Tyndall scattering

      R S Subrahmanya K S Gururaja Doss Basrur Sanjiva Rao

      More Details Abstract Fulltext PDF

      The study of the action of an electric field on the scattering intensity of sols has thus led to interesting results. The study is useful in determining the shape of the particles. The present technique would be supplementary to the studies of double refraction, in that the latter cannot be conveniently investigated in a highly scattering system. With slightly conducting sols, large fields can be used so as to produce saturation effects. Under such conditions, the use of rotating fields would bring about a unique orientation of the discs. A superposition of two A.C. fields of different cycles at right angles to each other would have the same effect as the circular field. The use of elliptical fields would reveal any want of equality of the two axes in the plane of discs of flat particles. The technique itself is simpler than the flow technique. Since there is often a large difference in the dielectric constant between the particles and the medium, the orientation is marked even with small fields, and the electric field is thus more powerful than the magnetic field in bringing about orientation.

    • Efficiency of wetting agents

      T Krishnappa K S Gururaja Doss Basrur Sanjiva Rao

      More Details Abstract Fulltext PDF

      The relative efficiencies of some of the common wetting agents have been determined by measuring the surface tension of five-minute-old surfaces of the solutions using the ring method in a modified form. Aqueous solutions giving a surface tension of 37 dynes per cm. may be considered to have good wetting properties. It is found that wetting power is not necessarily associated with detergent and emulsifying properties.

      Salts greatly increase wetting power. Bivalent cations are more effective than univalent cations in increasing wetting power. A moderate degree of hardness in water employed in preparing solutions of wetting agents may be of advantage in the textile industry.

      The maximum bubble pressure method is shown to be unsuitable for the measurement of surface tension of solutions which show a variation with time. A rough idea of the order of wetting efficiencies of wetting agents can however be obtained by measuring the surface tension of a five-second-old surface by this method.

    • Spreading of casein and derivatives

      G N Subba Rao K S Gururaja Doss Basrur Sanjiva Rao

      More Details Abstract Fulltext PDF

      Casein has been spread from its aqueous solutions by different methods and it has been found that the modified band method is the most suitable for the study of protein films.

      Effect of salts on the spreading of casein has been studied. The results obtained can be explained on the basis that two different factors, solubility and the electric charge of the protein molecule influence spreading.

      Treatment of the protein with formaldehyde causes a decrease in spreading. Change in pH affects spreading of formolised casein to a smaller degree.

      Sodium metaphosphate diminishes markedly the spreading of casein. Trichloracetic acid, however, has no effect.

      Deaminisation of casein alters the spreading properties and gives unstable films on acidulated water. No films can be got on distilled water.

      The spreading properties of an isodisperse fraction of casein have been studied. The limiting area of this fraction has been found to be of the same order as that of the original material.

    • Effect of surface-active agents on indicators

      T Krishnappa K S Gururaja Doss B Sanjiva Rao

      More Details Fulltext PDF
    • Equilibrium surface tension of aqueous solutions of Nekal BX and the effect of salts

      T Krishnappa K S Gururaja Doss Basrur Sanjiva Rao

      More Details Fulltext PDF
    • Aging of surfaces of solutions - Part VI. Surface aging of casein solutions

      G N Subba Rao K S Gururaja Doss Basrur Sanjiva Rao

      More Details Fulltext PDF
    • Reduction processes at the dropping mercury electrode in pulsating fields

      K S Gururaja Doss H P Agarwal

      More Details Abstract Fulltext PDF

      The work of Breyer and Gutmann on the effect of superimposing alternating fields on the reduction processes occurring at the dropping mercury electrode, has been extended to lead solutions. The work has been done at different frequencies of the alternating field. All the results obtained are interpretable on the basis of the diminution in the overall capacitative impedance of the dropping electrode as the half-wave potential is approached as well as when the frequency of the alternating field increases. These results are largely confirmed by direct observations on phase shifts by means of the oscillograph.

    • The effect of wetting agents on the adsorption of crystal violet by glass

      R S Subrahmanya M R A Rao K S Gururaja Doss

      More Details Abstract Fulltext PDF

      1. The effect of pH and of wetting agents on the adsorption of crystal violet at the surface of glass has been investigated.

      2. At low pH values, a wetting agent at first increases the adsorption of the dye. But with an increase in the concentration of the wetting agent the adsorption falls off rapidly and drops almost to zero. At higher pH values the wetting agent diminishes increased adsorption of the dye. An explanation has been offered to account for these observations.

  •  

© 2021-2022 Indian Academy of Sciences, Bengaluru.