Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "molecular dynamics" wg kryterium: Temat

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-9 z 9
    Tytuł:
    Synergic Effect of sodium oleate (NaOL) and benzohydroxamic acid (BHA) on flotation of wolframite
    Autorzy:
    Bu, H.
    Cao, M.
    Gao, Y.
    Huang, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/110377.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    wolframit
    mixed collector
    molecular dynamics
    synergic effect
    Opis:
    In this work, two collectors sodium oleate (NaOL) and benzohydroxamic acid (BHA) were used to study the synergic effect in wolframite flotation. The flotation behaviour of these collectors was investigated at various NaOL:BHA ratios. Results show that the mixtures of NaOL with BHA of different ratios result in large improvements in the recovery of wolframite and the 9:1 NaOL:BHA ratio of collector mixture produced the highest wolframite recovery. The amount of NaOL and BHA adsorbed on wolframite was measured for these various reagent mixtures. Compared with pure NaOL, the addition of a certain proportion of BHA is beneficial for NaOL adsorption. Molecular dynamics simulations indicate the formation of HOL–HA (oleic acid–benzohydroxamic acid) complex can take place spontaneously in NaOL–BHA system. Additionally, HOL–HA complex interact with the huebnerite (MnWO4) surface more easily than NaOL–HOL (the highest surface active composition in sodium oleate) and the addition of BHA enable the H of carboxyl group in HOL to generate hydrogen bonds with O atoms of huebnerite surface, resulting in a stronger affinity of mixed surfactants. These results reveal that in a binary NaOL–BHA system, the BHA can encourage greater adsorption of the NaOL.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2017, 53, 1; 82-93
    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
    Tytuł:
    Flotation and molecular dynamics simulation of muscovite with mixed anionic/cationic collectors
    Autorzy:
    Bai, Yang
    Li, Caixia
    An, Hongyun
    Wang, Guoliang
    Zhao, Xin
    Zhang, Jinqi
    Powiązania:
    https://bibliotekanauki.pl/articles/110125.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    muscovite
    mixed anionic/cationic collectors
    flotation
    molecular dynamics simulation
    Opis:
    In this study, three kinds of anionic collectors (sodium oleate (NaOl), sodium dodecyl sulfonate (SDS) and naphthenic acid (NA)) were used in combination with dodecylamine (DDA) to investigate the flotation behavior of muscovite under the action of different mixed anionic/cationic collectors, and their mechanisms for adsorption on the muscovite (001) Surface were clarified using molecular dynamics simulations. The flotation results indicated that different mixed anionic/cationic collectors could improve the recovery of muscovite to varying degrees, but the optimum molar ratio of anionic collectors to DDA and the optimum mixed collector dosage were different. Molecular dynamics simulations showed that the mixed anionic/cationic collectors could significantly increase the hydrophobicity of the muscovite, as evidenced by the decrease in the calculated water molecule density on the muscovite surface and the diffusion coefficient of water molecules at the solid/liquid interface. The interaction between the amino group and the polar group of anionic collectors reduced the electrostatic repulsion between DDA cations and theoretically increased the adsorption capacity of the mixed anionic/cationic collectors on the muscovite surface. Moreover, DDA/NA and DDA/NaOl could improve the calculated carbon atom density on the muscovite surface, which enhanced the hydrophobic association between nonpolar carbon chains, thus further achieving an enhanced flotation performance.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2020, 56, 2; 313-324
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure and dynamics of water adsorbed on the lignite surface: Molecular dynamics simulation
    Autorzy:
    You, Xiaofang
    He, Meng
    Cao, Xiaoqiang
    Lyu, Xianjun
    Li, Lin
    Powiązania:
    https://bibliotekanauki.pl/articles/109688.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    low rank coal
    water molecule
    oxygen-containing functional groups
    molecular dynamics
    Opis:
    The effects of oxygen-containing functional groups on the structure and dynamic properties of water molecules near a lignite surface were investigated through molecular dynamics (MD) simulations. Because of its complex composition and structure, a graphite surface containing hydroxyl, carboxyl, and carbonyl groups was used to represent the lignite surface model. According to X-ray photoelectron spectroscopic (XPS) results, the composing proportion of hydroxyl, carbonyl and carboxyl is 21:13:6. The density profiles of oxygen and hydrogen atoms indicate that the brown coal surface characteristics influence the structural and dynamic properties of water molecules. The interfacial water is much more ordered than bulk water. The results of the radial distribution functions, mean square displacements, and local self-diffusion coefficients for the water molecules in the vicinity of three oxygen-containing functional groups confirmed that carboxyl groups are the preferential adsorption sites.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 1; 10-20
    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:
    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 the oxygen-containing functional group on the adsorption of hydrocarbon oily collectors on coal surfaces
    Autorzy:
    Wan, He
    Hu, Xianglin
    Luukkanen, Saija
    Qu, Juanping
    Zhang, Chonghui
    Xue, Jiwei
    Li, Hui
    Yang, Wei
    Yang, Shenghong
    Bu, Xianzhong
    Powiązania:
    https://bibliotekanauki.pl/articles/2146920.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    oxygen-containing functional groups
    hydrocarbon oily collectors
    molecular dynamics simulation
    coal surfaces
    adsorption
    Opis:
    The oxygen-containing functional groups (OCFG) on the coal surface affect the adsorption effect of hydrocarbon oily collectors (HOC). An investigation of the interaction between the HOC and OCFG in the absence and presence of water is conducive to understanding the effect of OCFG type on the adsorption of HOC on the coal surface. In this paper, FTIR analysis was used to analyze the OCFG type of coal surface. The adsorption behavior of HOC on different OCFG surfaces was investigated using molecular dynamics simulation. The results indicated the presence of OCFG such as -OH, -COOH, -C=O, and -COCH3 on the coal surface. In conditions without water, the effect of OCFG on HOC adsorption capability follows the order -COOH > -C=O > -OH > -COCH3. In an aqueous solution, the effect of OCFG on HOC adsorption capability follows the order -C=O>-COCH3>-OH>-COOH. Moreover, the hydrophilicity of OCFG is the key factor that affects the adsorption effect of HOC. In other words, the adsorption effect of HOC on the coal surface in an aqueous solution does not depend on the strength of the interaction between the OCFG and HOC in the absence of water, but on the hydrophilicity of the OCFG. The -COOH and -OH on the coal surface are not conducive to the adsorption of HOC onto the coal surface. Masking the -COOH and -OH of the coal surface is beneficial in improving the coal flotation performance with HOC as a collector.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 149937
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Morphological analysis of organo-montmorillonites via MD simulations
    Autorzy:
    Karataş, Deniz
    Tekin, Adem
    Can, Muhammed F.
    Xu, Zhenghe
    Çelik, Mehmet S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2146936.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    organo-montmorillonite
    tetradecyl dimethyl ethyl benzyl ammonium chloride
    molecular dynamics simulation
    cation exchange capacity
    binding energy
    Opis:
    Adsorption on clay surfaces has been studied intensively in recent years. The most curious subject of these studies, which are generally experimental, is how the surfactants are adsorbed at the atomic level to the surface. In this study, the adsorption of quaternary amine salt (tetradecyl dimethyl ethyl benzyl ammonium chloride–TDEBAC) to sodium montmorillonite (Na-MMT) with various cation exchange capacities (CEC) was investigated by using Molecular Dynamics (MD) simulation. In the simulations, as in the experimental studies, it was revealed that the surfactants were both adsorbed on to basal surfaces and settled between the layers. From the morphological analysis obtained from MD simulations, it was calculated that the inter-molecular interaction between the layers was higher than on the basal surface. For example, for the model with 118 CEC motif, the binding energy of all three surfactants in the models with the hydrophilic heads facing the same direction was calculated as -678.18 kcal/mol at the basal surface, while this value was found to be -688.90 kcal/mol in the interlayer. The more striking result is that in the simulations made by turning the head of the middle one of the three surfactants towards the tails of the right and left ones, only -34.86 kcal/mol binding energy was calculated on the basal surface, while this value was -525.63 kcal/mol in the interlayer. As compared middle reversed surfactant models with the same direction ones, despite increased CEC the intermolecular interaction decreased for the basal surface, but the interaction increased between the layers.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2022, 58, 5; art. no. 152499
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synergistic mechanism of dodecylamine/octanol mixtures enhancing lepidolite flotation from the self-aggregation behaviors at the air/liquid interface
    Autorzy:
    Bai, Yang
    Xu, Mengxu
    Wen, Weixiang
    Zhu, Shifei
    Mo, Weichen
    Yan, Pingke
    Powiązania:
    https://bibliotekanauki.pl/articles/27323641.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    DDA/OCT mixtures
    self-aggregation behaviors
    flotation foam
    molecular dynamics simulations
    surface tension
    air interface
    liquid interface
    Opis:
    Surface tension measurements and molecular dynamics (MD) simulations were used to explore the flotation foam properties and self-aggregation behaviors of dodecylamine (DDA)/octanol (OCT) mixtures formed with different mole ratios at the air/liquid interface. Based on the surface and thermodynamic parameters, the DDA/OCT mixtures exhibited greater interfacial activities and adsorption capacities than their individual components. The MD simulations showed that DDA and OCT were aggregated through hydrogen bonding, coulombic forces and hydrophobic association. OCT was inserted into the DDA adsorption layer, causing the alkyl chains of both DDA and OCT to extend from water to air at varying heights and angles. The addition of OCT improved the hydration of the amino groups and reduced the overall number of hydrogen bonds. The stability of the flotation foam decreased, and the high viscosity and difficult defoaming of the DDA flotation foam were significantly improved. When the DDA/OCT mole ratio was 2:1, the included angle formed between the alkyl chains and the interface was maximized, leading to enhanced compatibility among the alkyl chains, and the hydrogen bond energy was relatively large, which showed a strong synergistic effect. The MD simulation findings were consistent with the results obtained from the lepidolite flotation and surface tension experiments conducted in this study; our results could provide a theoretical foundation for the selection of superior mixed collectors and frothers.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 176510
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies