Flocculation and adsorption-desorption mechanism of polymers on albite

2000 ◽  
pp. C5-24-C5-30
Author(s):  
I. Kurşun ◽  
B. Ipekoğlu ◽  
M.S. Çelik ◽  
Y. Kaytaz
Keyword(s):  
Desorption Mechanism ◽  
Adsorption Desorption

Modeling the Bottom-Up Filling of Through-Silicon vias Through Suppressor Adsorption/Desorption Mechanism

2013 ◽  
Vol 160 (12) ◽  
pp. D3051-D3056 ◽  
Author(s):  
Liu Yang ◽  
Aleksandar Radisic ◽  
Johan Deconinck ◽  
Philippe M. Vereecken
Keyword(s):  
Bottom Up ◽  
Through Silicon Vias ◽  
Desorption Mechanism ◽  
Silicon Vias ◽  
Adsorption Desorption

Experimental study and molecular dynamics simulation of wall slip in a micro-extrusion flowing process

2011 ◽  
Vol 225 (5) ◽  
pp. 1175-1190 ◽  
Author(s):  
D Zhao ◽  
Y Jin ◽  
M Wang ◽  
M Song
Keyword(s):  
Molecular Dynamics ◽  
Shear Stress ◽  
Molecular Dynamics Simulation ◽  
Slip Velocity ◽  
Polymer Melts ◽  
Critical Shear Stress ◽  
Wall Slip ◽  
Dynamics Simulation ◽  
Desorption Mechanism ◽  
Adsorption Desorption

Wall slip is one of the most important characteristics of polymer melts’ elasticity behaviours as well as the most significant factor which affects the flow of polymer melts. Based on the traditional Mooney method, through a double-barrel capillary rheometer, the relationship between velocities of wall slip, shear stress, shear rate, diameters of dies, and temperature of polypropylene (PP), high-density polyethylene (HDPE), polystyrene (PS), and polymethylmethacrylate (PMMA) is explored. The results indicate that the velocities of the wall slip of PP and HDPE increase apparently with shear stress and slightly with temperature. Meanwhile, the rise of temperature results in the decrease of critical shear stress. The wall-slip velocities of PS and PMMA are negative which means that the Mooney method based on the adsorption–desorption mechanism has determinate limitation to calculate the wall-slip velocity. Based on the entanglement–disentanglement mechanism, a new wall-slip model is built. With the new model, the calculation values of velocity of PP and HDPE correspond to the experimental values very well and the velocities of PS and PMMA are positive. The velocities of PS and PMMA increase obviously with the rise of shear stress. The rise of temperature results in the increase of velocity and decrease of critical shear stress. Then, the molecular dynamics simulation is used to investigate the combining energy between four polymer melts and the inside wall. The results show that at the given temperature and pressure, the molecules of PS and PMMA combine with atoms of the wall more tightly than those of PP and HDPE which means when wall slip occurs, the molecules of PS and PMMA near the wall will adsorb to the surface of the wall. However, those of PP and HDPE will be easy to slip. Therefore, the wall-slip mechanism of PP and HDPE is the adsorption–desorption mechanism, and that of PS and PMMA is the entanglement–disentanglement mechanism. According to the different wall-slip mechanisms of four polymers, an all-sided calculation method of wall-slip velocity is raised which consummates the theory of wall slip of polymer melts.

scholarly journals Surfactant Monolayer Bending Elasticity in Lipase Containing Bicontinuous Microemulsions

2021 ◽  
Vol 8 ◽  
Author(s):  
Sandra Engelskirchen ◽  
Stefan Wellert ◽  
Olaf Holderer ◽  
Henrich Frielinghaus ◽  
Michaela Laupheimer ◽  
...  
Keyword(s):  
Spin Echo ◽  
Neutron Spin ◽  
Major Drawback ◽  
Neutron Spin Echo ◽  
Bending Elasticity ◽  
Bicontinuous Microemulsion ◽  
Catalyzed Reactions ◽  
Desorption Mechanism ◽  
Adsorption Desorption ◽  
High Degree

Lipase-catalyzed reactions offer many advantages among which a high degree of selectivity combined with the possibility to convert even non-natural substrates are of particular interest. A major drawback in the applicability of lipases in the conversion of synthetically interesting, non-natural substrates is the substantial insolubility of such substrates in water. The conversion of substrates, natural or non-natural, by lipases generally involves the presence of a water–oil interface. In the present paper, we exploit the fact that the presence of lipases, in particular the lipase from Candida antarctica B (CalB), changes the bending elastic properties of a surfactant monolayer in a bicontinuous microemulsion consisting of D2O/NaCl -n-(d)-octane-pentaethylene glycol monodecyl ether (C10E5) in a similar manner as previously observed for amphiphilic block-copolymers. To determine the bending elastic constant, we have used two approaches, small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy. The time-averaged structure from SANS showed a slight decrease in bending elasticity, while on nanosecond time scales as probed with NSE, a stiffening has been observed, which was attributed to adsorption/desorption mechanisms of CalB at the surfactant monolayer. The results allow to derive further information on the influence of CalB on the composition and bending elasticity of the surfactant monolayer itself as well as the underlying adsorption/desorption mechanism.

scholarly journals Adsorption-Desorption Mechanism of Synthesized Benzimidazole Based Fungicide 2-(3’-Pyridyl) on Selected Soil Minerals

2019 ◽  
Vol 10 (2) ◽  
pp. 38-44 ◽  
Author(s):  
Khuram Shahzad Ahmad ◽  
Shaan Bibi Jaffri ◽  
Saba Gul ◽  
Khadija Ikhlaq ◽  
Maryam Javaid ◽  
...  
Keyword(s):  
Surface Area ◽  
Physicochemical Characteristics ◽  
Soil Profiles ◽  
Adsorption Coefficient ◽  
Soil Minerals ◽  
Adsorption And Desorption ◽  
Desorption Mechanism ◽  
Adsorption Desorption ◽  
Residual Plots ◽  
Research Show

The adsorption and desorption phenomenon of synthesized Benzimidazole based fungicide, 2-(3’-pyridyl)benzimidazole (PyBlm), was investigated by batch equilibrium method. Four soil minerals were utilized for thesorption studies including; alumina, silica, muscovite and montmorillonite. Highest value of adsorption coefficient(Kd(ads)), obtained for montmorillonite mineral (Mx (Al, Fe, Mg4) Si8O20 (OH4)) was 2779 µg ml-1. Highest rate ofadsorption is attributable to its considerably large surface area of 628 m2g-1 and highest inter-lattice d-spacing, 10 Å.Highest desorption (Kd(des)) was also observed in montmorillonite mineral (21.45 µg ml-1). Montmorillonite thusdisplayed increased sorption capacity for PyBlm among all tested minerals. Hysteresis coefficient ranged from 0.58 to3. The results were statistically evaluated by using one-way analysis of variance (ANOVA). Furthermore, statisticalevaluation done with the help of Minitab 17 expressed the good fitting of the obtained results, which was shown bymeans of residual plots. Current research which suggests the variable adsorption and desorption of PyBlm expresses theprofound dependence of PyBlm interaction on the physicochemical characteristics of the selected minerals. Allminerals except montmorillonite expressing poor adsorption signifying the percolation of PyBlm through them towardsthe lower soil profiles. Results obtained in the present research show of that montmorillonite in firmly interacting withthe PyBlm molecules and thus alleviating the possibility of PyBlm percolation to lower soil profiles.

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