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Wyszukujesz frazę "Miller, J.D." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Dodecyl amine adsorption at different interfaces during bubble attachment/detachment at a silica surface
Autorzy:
Wang, X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/110684.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
VSFS
air bubble attachment
amine adsorption density
Opis:
The reverse flotation of quartz and other gangue silicate minerals with alkyl amines is an important and well known strategy for the processing of iron ore, low grade bauxite ore, and phosphate rock. Some details of amine adsorption by quartz have been described in the literature, but little is known about the disposition of amine during bubble attachment. Now, a new experimental procedure involving vibrational sum frequency spectroscopy (VSFS) has been developed to provide, for the first time, a more detailed analysis of the state of dodecyl amine (DDA) adsorption at different interfaces during bubble attachment/detachment at a silica surface. The results show that the hydrophobic surface state at the silica surface is created by the transfer of a well-organized monolayer of DDA from the bubble surface to the silica surface during bubble contact and attachment.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 81-88
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular dynamics simulations study of nano bubble attachment at hydrophobic surfaces
Autorzy:
Jin, J.
Dang, L. X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/109533.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
molecular dynamics simulations (MDS)
film stability
bubble attachment
interfacial water structure
Opis:
Bubble attachment phenomena are examined using Molecular Dynamics Simulations (MDS) for the first time. The simulation involves a nitrogen nano bubble containing 906 nitrogen molecules in a water phase with 74,000 water molecules at molybdenite surfaces. During a simulation period of 1 ns, film rupture and displacement occurs. The attached nanobubble at the hydrophobic molybdenite face surface results in a contact angle of about 90º. This spontaneous attachment is due to a “water exclusion zone” at the molybdenite face surface and can be explained by a van der Waals (vdW) attractive force, as discussed in the literature. In contrast, the film is stable at the hydrophilic quartz (001) surface and the bubble does not attach. Contact angles determined from MD simulations are reported, and these results agree well with experimental and MDS sessile drop results. In this way, film stability and bubble attachment are described with respect to interfacial water structure for surfaces of different polarity. Interfacial water molecules at the hydrophobic molybdenite face surface have relatively weak interactions with the surface when compared to the hydrophilic quartz (001) surface, as revealed by the presence of a 3 Å “water exclusion zone” at the molybdenite/water interface. The molybdenite armchair-edge and zigzag-edge surfaces show a comparably slow process for film rupture and displacement when compared to the molybdenite face surface, which is consistent with their relatively weak hydrophobic character.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 89-101
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of oxidation on the wetting of coal surfaces by water: experimental and molecular dynamics simulation studies
Autorzy:
Li, E.
Lu, Y.
Cheng, F.
Wang, X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/109792.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wettability
oxidation
molecular dynamics simulation
hydrogen bonding
contact angles
coal surfaces
Opis:
The wettability of coal surfaces by water continues to be one of the key factors which determines the success of coal flotation. Consequently, oxidation of coal surfaces is a fundamental issue of interest. In this work, the effect of oxidation on the wetting of coal surfaces and the interaction between water molecules and oxygen-containing sites at the coal surface was investigated based on advancing/receding contact angle measurements and molecular dynamics simulations. For the simulation studies, a flat coal surface was constructed with the assistance of the molecular repulsion between graphite surfaces and the assembly of Wiser coal molecules. Our results indicated that the simulated advancing and receding contact angles were very similar, and both of them decreased, as expected, with an increase of hydroxyl sites at the coal surface. The good agreement between the simulated advancing/receding contact angles and the experimental receding contact angle values suggested that the configuration of the systems and the set of parameters for the simulation were appropriate. The spreading of water is mainly due to the hydrogen bonds formed between the interfacial water molecules and the hydroxyl sites at the coal surface. The hydroxyl groups show stronger hydration capacity than other oxygen-containing groups according to the calculated hydrogen bonds and interaction energies.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1039-1051
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water film structure during rupture as revealed by MDS image analysis
Autorzy:
Truong, N. T.
Dang, L. X.
Lin, C.-L.
Wang, X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/110251.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image processing
molecular dynamics simulation
film stability
molecular porosity
Opis:
The structure of thin water films during the rupture process was investigated by a new approach, which combines molecular dynamics simulation (MDS) with image processing analysis. The analysis procedure was developed to convert MDS trajectories to readable 3D images. The water films were studied at different thicknesses by MDS to determine the critical thickness at which the film ruptures. The potential energy of each specific film thickness during the simulation time was analyzed, and the results showed that the potential energy of stable films remained unchanged while the potential energy kept decreasing for films which ruptured during the simulation time. By applying the new procedure, the molecular porosity, which is defined as the void fraction between the volume of molecular pores in the water film and the total volume of the water film, was calculated. The results of molecular porosity for different film thicknesses during the simulation time suggested a critical molecular porosity as 49%. In other words, stable films have a molecular porosity of less than 49%. If a water film has a molecular porosity greater than 49%, rupture occurs during the simulation.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1060-1069
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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