The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Reinhard Miller - One of the best experts on this subject based on the ideXlab platform.
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Dynamic surface tension measurements of surfactant solutions using the maximum Bubble Pressure Method - limits of applicability
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004Co-Authors: V. B. Fainerman, Alexander V. Makievski, S. V. Lylyk, V. N. Kazakov, Reinhard MillerAbstract:One of the essential differences in the design of Bubble Pressure tensiometers consists in the geometry of the measuring capillaries. To reach extremely short adsorption times of milliseconds and below, the so-called deadtime of the capillaries must be of the order of some 10 ms. In particular, for concentrated surfactant solutions, such as micellar solutions, short deadtimes are needed to minimize the initial surfactant load of the generated Bubbles. A theoretical model is derived and confirmed by experiments performed for a wide range of experimental conditions, mainly in respect to variations in deadtime and Bubble volume.
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Studies of concentrated surfactant solutions using the maximum Bubble Pressure Method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2000Co-Authors: N.a. Mishchuk, V. B. Fainerman, Volodymyr I. Kovalchuk, Reinhard Miller, S. S. DukhinAbstract:Abstract An analysis of the adsorption process during the deadtime period in maximum Bubble Pressure experiments is performed. The adsorption dynamics is calculated for the actual surface area increase of a Bubble in a surfactant solution, which depends on characteristic system parameters such as the length and diameter of the capillary and the surfactant's concentration and adsorption activity. Under certain conditions, the calculations yield extreme adsorption behavior. In particular, a sharp adsorption minimum is predicted in the initial period of the deadtime interval. This effect can be relevant for the interpretation of Bubble Pressure results for concentrated surfactant solutions, when the initial adsorption of the surfactant is significant. In this case, the experimental results should be presented as a function of the effective total time (deadtime plus lifetime) rather than the effective lifetime.
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THE EFFECT OF CAPILLARY CHARACTERISTICS ON THE RESULTS OF DYNAMIC SURFACE TENSION MEASUREMENTS USING THE MAXIMUM Bubble Pressure Method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998Co-Authors: S. V. Lylyk, Alexander V. Makievski, V. B. Fainerman, Volodymyr I. Kovalchuk, K. H. Schano, Reinhard MillerAbstract:Abstract The dynamic surface tension of Triton X-100 solutions was measured using the maximum Bubble Pressure Method (MBPM). The data obtained depended on the geometry and material of the capillaries employed. It is shown that reliable results are obtained with short capillaries of hydrophobic internal surfaces. The effect of the ratio of the Bubble volume to measuring system volume on the measured dynamic surface tension is studied. Recommendations are given for the optimum choice of the capillary to be employed in the MBPM. High-speed video imaging is used for studying the hydrodynamics of the liquid meniscus after Bubble separation in hydrophilic and hydrophobic capillaries.
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Dynamic Surface Tension Measurements in the Sub-millisecond Range
Journal of Colloid and Interface Science, 1995Co-Authors: V. B. Fainerman, Reinhard MillerAbstract:The dynamic surface tensions of aqueous solutions of Tritons (X-100, X-114, X-165, X-305, and X-405) and n-hexanol were measured with a maximum Bubble Pressure Method in the time interval from 0.1 ms to 1 s. The possibility of formation and detection of Bubbles up to a frequency of 100 Hz is needed for studies in the sub-millisecond range, which has been arranged by a special design of a measuring cell for the commercial Bubble Pressure tensiometer MPT1. An analysis is given for the applicability of the Bubble Pressure Method to extremely short adsorption times.
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The measurement of dynamic surface tension by the maximum Bubble Pressure Method
Colloid and Polymer Science, 1994Co-Authors: V. B. Fainerman, Reinhard Miller, Paul JoosAbstract:The principle of maximum Pressure in a Bubble for measurements of dynamic surface tension is realized in a fully automatically operating apparatus. The set-up yields data in the time interval from 1 ms up to several seconds and can be temperature controlled from 5° to 80°C. Experimental data obtained for different surfactants and gelatine in water and/or water/glycerine mixtures at different temperatures are discussed. A direct comparison with results from oscillating jet and inclined plate experiments shows excellent agreement.
V. B. Fainerman - One of the best experts on this subject based on the ideXlab platform.
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Dynamic surface tension measurements of surfactant solutions using the maximum Bubble Pressure Method - limits of applicability
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004Co-Authors: V. B. Fainerman, Alexander V. Makievski, S. V. Lylyk, V. N. Kazakov, Reinhard MillerAbstract:One of the essential differences in the design of Bubble Pressure tensiometers consists in the geometry of the measuring capillaries. To reach extremely short adsorption times of milliseconds and below, the so-called deadtime of the capillaries must be of the order of some 10 ms. In particular, for concentrated surfactant solutions, such as micellar solutions, short deadtimes are needed to minimize the initial surfactant load of the generated Bubbles. A theoretical model is derived and confirmed by experiments performed for a wide range of experimental conditions, mainly in respect to variations in deadtime and Bubble volume.
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Studies of concentrated surfactant solutions using the maximum Bubble Pressure Method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2000Co-Authors: N.a. Mishchuk, V. B. Fainerman, Volodymyr I. Kovalchuk, Reinhard Miller, S. S. DukhinAbstract:Abstract An analysis of the adsorption process during the deadtime period in maximum Bubble Pressure experiments is performed. The adsorption dynamics is calculated for the actual surface area increase of a Bubble in a surfactant solution, which depends on characteristic system parameters such as the length and diameter of the capillary and the surfactant's concentration and adsorption activity. Under certain conditions, the calculations yield extreme adsorption behavior. In particular, a sharp adsorption minimum is predicted in the initial period of the deadtime interval. This effect can be relevant for the interpretation of Bubble Pressure results for concentrated surfactant solutions, when the initial adsorption of the surfactant is significant. In this case, the experimental results should be presented as a function of the effective total time (deadtime plus lifetime) rather than the effective lifetime.
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THE EFFECT OF CAPILLARY CHARACTERISTICS ON THE RESULTS OF DYNAMIC SURFACE TENSION MEASUREMENTS USING THE MAXIMUM Bubble Pressure Method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998Co-Authors: S. V. Lylyk, Alexander V. Makievski, V. B. Fainerman, Volodymyr I. Kovalchuk, K. H. Schano, Reinhard MillerAbstract:Abstract The dynamic surface tension of Triton X-100 solutions was measured using the maximum Bubble Pressure Method (MBPM). The data obtained depended on the geometry and material of the capillaries employed. It is shown that reliable results are obtained with short capillaries of hydrophobic internal surfaces. The effect of the ratio of the Bubble volume to measuring system volume on the measured dynamic surface tension is studied. Recommendations are given for the optimum choice of the capillary to be employed in the MBPM. High-speed video imaging is used for studying the hydrodynamics of the liquid meniscus after Bubble separation in hydrophilic and hydrophobic capillaries.
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Dynamic Surface Tension Measurements in the Sub-millisecond Range
Journal of Colloid and Interface Science, 1995Co-Authors: V. B. Fainerman, Reinhard MillerAbstract:The dynamic surface tensions of aqueous solutions of Tritons (X-100, X-114, X-165, X-305, and X-405) and n-hexanol were measured with a maximum Bubble Pressure Method in the time interval from 0.1 ms to 1 s. The possibility of formation and detection of Bubbles up to a frequency of 100 Hz is needed for studies in the sub-millisecond range, which has been arranged by a special design of a measuring cell for the commercial Bubble Pressure tensiometer MPT1. An analysis is given for the applicability of the Bubble Pressure Method to extremely short adsorption times.
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The measurement of dynamic surface tension by the maximum Bubble Pressure Method
Colloid and Polymer Science, 1994Co-Authors: V. B. Fainerman, Reinhard Miller, Paul JoosAbstract:The principle of maximum Pressure in a Bubble for measurements of dynamic surface tension is realized in a fully automatically operating apparatus. The set-up yields data in the time interval from 1 ms up to several seconds and can be temperature controlled from 5° to 80°C. Experimental data obtained for different surfactants and gelatine in water and/or water/glycerine mixtures at different temperatures are discussed. A direct comparison with results from oscillating jet and inclined plate experiments shows excellent agreement.
Vladimír Daněk - One of the best experts on this subject based on the ideXlab platform.
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Surface Tension of Melts of the System KF + K2NbF7 + Nb2O5
Journal of Chemical & Engineering Data, 2005Co-Authors: Blanka Kubíková And, Vladimír DaněkAbstract:The surface tension of the molten system KF(1) + K2NbF7(2) + Nb2O5(3) up to x3 = 0.2 has been investigated using the maximum Bubble Pressure Method over the temperature range from 1133 K to 1233 K. The uncertainty of the surface tension measurement was estimated to be ±1.5%. On the basis of the data presented, the composition dependence of the surface tension and the surface tension excess were calculated.
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Surface Tension of the System LiF-NaF-K2NbF7
Zeitschrift für Physikalische Chemie, 2003Co-Authors: B. Kubíková, R. Vasiliev, František Šimko, Vladimír DaněkAbstract:The surface tension of the molten system LiF-NaF-K 2 NbF 7 has been determined using the maximum Bubble Pressure Method. The error in the surface tension measurement was estimated to be ′1%. Based on the obtained data the composition dependence of the surface tension and of the surface tension excess of the investigated system was calculated. The results are discussed in term of the anionic composition. From the surface tension excess results the negative deviation from the ideal behavior of the studied system.
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Surface Tension of Melts of the System KF—K2MoO4—SiO2
2003Co-Authors: Miroslav Boča, Marián Kucharík, Roman Vasiljev, Vladimír DaněkAbstract:The surface tension of the molten system KF—K2MoO4—SiO2 has been determined using the maximum Bubble Pressure Method. The error in the surface tension measurement was estimated to be ± 1 %. On the basis of the obtained data the concentration dependence of the surface tension and of the surface tension excess of the investigated system was calculated. The results are discussed in terms of the anionic composition.
Alexander V. Makievski - One of the best experts on this subject based on the ideXlab platform.
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Dynamic surface tension measurements of surfactant solutions using the maximum Bubble Pressure Method - limits of applicability
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2004Co-Authors: V. B. Fainerman, Alexander V. Makievski, S. V. Lylyk, V. N. Kazakov, Reinhard MillerAbstract:One of the essential differences in the design of Bubble Pressure tensiometers consists in the geometry of the measuring capillaries. To reach extremely short adsorption times of milliseconds and below, the so-called deadtime of the capillaries must be of the order of some 10 ms. In particular, for concentrated surfactant solutions, such as micellar solutions, short deadtimes are needed to minimize the initial surfactant load of the generated Bubbles. A theoretical model is derived and confirmed by experiments performed for a wide range of experimental conditions, mainly in respect to variations in deadtime and Bubble volume.
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THE EFFECT OF CAPILLARY CHARACTERISTICS ON THE RESULTS OF DYNAMIC SURFACE TENSION MEASUREMENTS USING THE MAXIMUM Bubble Pressure Method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1998Co-Authors: S. V. Lylyk, Alexander V. Makievski, V. B. Fainerman, Volodymyr I. Kovalchuk, K. H. Schano, Reinhard MillerAbstract:Abstract The dynamic surface tension of Triton X-100 solutions was measured using the maximum Bubble Pressure Method (MBPM). The data obtained depended on the geometry and material of the capillaries employed. It is shown that reliable results are obtained with short capillaries of hydrophobic internal surfaces. The effect of the ratio of the Bubble volume to measuring system volume on the measured dynamic surface tension is studied. Recommendations are given for the optimum choice of the capillary to be employed in the MBPM. High-speed video imaging is used for studying the hydrodynamics of the liquid meniscus after Bubble separation in hydrophilic and hydrophobic capillaries.
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Dynamic Surface Tension of Micellar Triton X-100 Solutions by the Maximum-Bubble-Pressure Method
Journal of Colloid and Interface Science, 1994Co-Authors: Alexander V. Makievski, V. B. Fainerman, Paul JoosAbstract:Abstract The dynamic maximum-Bubble-Pressure Method was used to measure the dynamic surface tension of Triton X-100 solutions (at the CMC and at concentrations above the CMC). Measurements were performed at 30.0, 40.0, 50.0, and 60.0°C. The results at 30.0°C are in excellent agreement with the data obtained through other Methods (oscillating jet and inclined plate). The demicellization rate constant is obtained according to a Method previously described. It is found that this demicellization rate constant depends strongly on the surfactant concentration, in agreement with a previous investigation, using oscillating jet and inclined plate techniques. It is also found that this rate constant is nearly independent of the temperature, pointing to an entropic effect.
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The measurement of dynamic surface tensions of highly viscous- liquids by the maximum Bubble Pressure Method
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1993Co-Authors: V. B. Fainerman, Alexander V. Makievski, Reinhard MillerAbstract:Abstract A newly designed apparatus based on the principle of maximum Bubble Pressure can be used for measuring the dynamic surface tension in a time interval from 1 ms to 10 s. The surface tension values for pure liquids obtained at small lifetimes are influenced by hydrodynamic effects. These effects depend on the viscosity of the liquid and the diameter of the capillary and decrease with increasing lifetimes. A procedure for correction is proposed and compared with experimental data for water—glycerine mixtures at different compositions and temperatures. Measurements of sodium tetradecyl sulphate in highly viscous water—glycerine mixtures lead to unexpected adsorption behaviour.
Mitsuhiro Fukuta - One of the best experts on this subject based on the ideXlab platform.
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Surface tension measurement of oil/refrigerant mixture by maximum Bubble Pressure Method
International Journal of Refrigeration, 2017Co-Authors: Mitsuhiro Fukuta, Masaaki Motozawa, Junki Sumiyama, Tomoya YanagisawaAbstract:Lubrication oil used in refrigerant compressors forms oil mist in the compressor shell. Some of the oil mist is discharged into a refrigeration cycle with refrigerant and causes degradation of heat transfer in heat exchangers. Since the generation of the oil mist is related to the Weber number, it is necessary to measure the surface tension of the oil/refrigerant mixture before discussing the oil mist generation in the compressor. In this study, the maximum Bubble Pressure Method was adapted to measure the surface tension of PAG (polyalkylene glycol) oil/CO2 mixture. The density of the mixture needed for the measurement was also carried out. It was found that the surface tension of PAG/CO2 mixture sharply decreases with an increase in the concentration of the refrigerant in the mixture. The surface tension of the mixture under 10 MPa and 100 ??C is estimated to be 14.6 mN m???1 by an extrapolation.
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surface tension measurement of oil refrigerant mixture by maximum Bubble Pressure Method
International Journal of Refrigeration-revue Internationale Du Froid, 2017Co-Authors: Mitsuhiro Fukuta, Junki Sumiyama, Masaaki Motozawa, Tadashi YanagisawaAbstract:Abstract Lubrication oil used in refrigerant compressors forms oil mist in the compressor shell. Some of the oil mist is discharged into a refrigeration cycle with refrigerant and causes degradation of heat transfer in heat exchangers. Since the generation of the oil mist is related to the Weber number, it is necessary to measure the surface tension of the oil/refrigerant mixture before discussing the oil mist generation in the compressor. In this study, the maximum Bubble Pressure Method was adapted to measure the surface tension of PAG (polyalkylene glycol) oil/CO2 mixture. The density of the mixture needed for the measurement was also carried out. It was found that the surface tension of PAG/CO2 mixture sharply decreases with an increase in the concentration of the refrigerant in the mixture. The surface tension of the mixture under 10 MPa and 100 °C is estimated to be 14.6 mN m−1 by an extrapolation.
