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Wyszukujesz frazę "Zawala, J." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Influence of dynamic adsorption layer formation on bubble attachment to quartz and mica surfaces in solutions of pure and mixed surface-active substances
Autorzy:
Wiertel-Pochopień, A.
Zawala, J.
Powiązania:
https://bibliotekanauki.pl/articles/109361.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quartz
bubble
mica
dynamic adsorption layer
wetting film
three-phase contact
Opis:
The paper presents systematic studies on influence of state of dynamic adsorption layer (DAL) induced at the rising bubble interface on time-scale of the bubble attachment to quartz and mica surfaces immersed in pure n-cetyl-trimethylammonium bromide (CTAB) and mixed octanol/CTAB solutions of different concentrations. It was found that in the case of pure CTAB solutions, the influence of DAL on time of bubble attachment and the three-phase contact (TPC) formation (tTPC) strongly depends on solution concentration. Generally, two solution concentration regimes were distinguished – low and high - for which different degree of solid surfaces hydrophobization was observed. It was determined that for low concentration regime the solid surface is only slightly hydrophobized while for high regime, hydrophobicity of the solid surface is much higher. Consequently, wetting film rupture for low concentration regime is governed by electrostatic interactions while for high concentration regime significance of these interactions is much smaller. As a result, the DAL influenced the film rupture in these two regimes in a quite different manner. For mixed n-octanol/CTAB solutions it was found that CTAB molecules presence is necessary condition for wetting film destabilization. Moreover, thanks to the developed approach, allowing control of initial adsorption coverage over the bubble surface (independently on concentration), it was proved that constant adsorption degree of CTAB molecules at the bubble surface in the mixture, leads to identical times of the TPC formation.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1083-1094
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-phase contact line expansion during air bubble attachment to hydrophobic solid surface – experiment and modeling
Autorzy:
Basarova, P.
Soušková, K.
Zawala, J.
Powiązania:
https://bibliotekanauki.pl/articles/110269.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Attachment
simulations
bubble
three-phase contact
dewetting
Opis:
Kinetics of spreading of the three-phase contact hole (dewetting) formed by an air bubble colliding with hydrophobic solid surface, after rupture of intervening liquid film, was studied both experimentally and numerically. During experiments it was found that evolution of the TPC line diameter with time occurs with characteristic S-shaped trend which, in consequence, causing rather unexpected maxima at the TPC line spreading velocity curves. It was determined that position of this maximum appears after 1-2 ms after TPC hole formation and its position (in respect to time) depends on the bubble diameter. In solution of surface-active substance this maximum was much smoother and longer. By means of complementary numerical calculations the source of maxima existence and differences in their position and shapes were explained. It was concluded that this effect has only hydrodynamic origin, caused by different course of bubble shape pulsations during TPC line formation and spreading, which depends on degree of liquid/gas interface immobilization (fluidity retardation).
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1095-1106
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface roughness in bubble attachment and flotation of highly hydrophobic solids in presence of frother – experiment and simulations
Autorzy:
Kosior, D.
Kowalczuk, P. B.
Zawala, J.
Powiązania:
https://bibliotekanauki.pl/articles/109319.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
surface roughness
attachment
flotation
kinetics
frother
Opis:
In this paper, the kinetic of the three-phase contact (TPC) formation and the flotation recovery of highly hydrophobic solids with different surface roughness were studied in pure water and aqueous solutions of n-octanol. The surface roughness varied between 1 to 100 μm. It was found that there was a strong influence of surface roughness on both kinetics of TPC formation and flotation. The time of three phase contact formation and flotation rate were much faster for rough surfaces in both water and aqueous solutions of frother. Irrespective of the surface roughness, at above a certain frother dose, the attachment time increased and the flotation rate decreased. It was related to the presence of air at the hydrophobic solid surfaces. The mechanism of this prolongation of the time of TPC formation at the solid surfaces with different roughness due to the frother overdosage was discussed, and the experimental data were confirmed by numerical simulations.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 63-72
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monitoring of contamination of coal processing plants and environmental waters using bubble velocity measurements – advantages and limitations
Autorzy:
Zawala, J.
Malysa, E.
Krzan, M.
Malysa, K.
Powiązania:
https://bibliotekanauki.pl/articles/110915.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bubble velocity
water purity
surface active contaminants
method detection
adsorption layer
Opis:
The paper presents fundamentals of a simple physicochemical method (SPMD) and analysis of results obtained when the method was applied for detection of organic contaminations (surface-active substances SAS) in samples of environmental and industrial waters. The method is based on measurements of variations of air bubble local velocities, which can be significantly changed in presence of surface-active contaminants. Lowering of the bubble velocity is a consequence of a motion induced dynamic adsorption layer (DAL) formed over surface of the rising bubble. The DAL formation retards the surface fluidity and the bubble rising velocity can be lowered by over 50% when the bubble surface is completely immobilized. We showed that the SPMD is a very sensitive tool (detection limit even below 1 ppm) for detection of various kinds of surface-active substances (ionic, non-ionic) in water samples. On the basis of results obtained using precise laboratory set-up, an accuracy of the SPMD is discussed. Moreover, effect of inert electrolyte addition on the bubble velocity lowering and value of detection limit of the SPMD is discussed. Simple approach, enabling quantitative analysis of the surface-active contaminants in samples collected, based on “equivalent concentrations” determination, is proposed. Results obtained for industrial (Jankowice and Knurow coal processing plants, Jaslo Refinery channel) and environmental waters (Wisloka and Ropa river) are used for detailed analysis and critical discussion of advantages and limitations of the SPMD.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 143-157
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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