scholarly journals Examination of inequivalent wetting on the crystal habit surfaces of RS-ibuprofen using grid-based molecular modelling

2018 ◽  
Vol 20 (17) ◽  
pp. 11622-11633 ◽  
Author(s):  
I. Rosbottom ◽  
J. H. Pickering ◽  
B. Etbon ◽  
R. B. Hammond ◽  
K. J. Roberts
Keyword(s):  
Molecular Modelling ◽  
Growth Rates ◽  
Crystal Surface ◽  
Surface Interactions ◽  
Surface Growth ◽  
Crystal Habit ◽  
Grid Based

Novel grid-based searching of solvent/crystal-surface interactions to investigate solution wetting impact upon crystal surface growth rates.

Ogre: A Python package for molecular crystal surface generation with applications to surface energy and crystal habit prediction

2020 ◽  
Vol 152 (24) ◽  
pp. 244122
Author(s):  
Shuyang Yang ◽  
Imanuel Bier ◽  
Wen Wen ◽  
Jiawei Zhan ◽  
Saeed Moayedpour ◽  
...  
Keyword(s):  
Surface Energy ◽  
Molecular Crystal ◽  
Crystal Surface ◽  
Crystal Habit ◽  
Surface Generation ◽  
Python Package

Kinetic aspects of major and trace elements in olivines from variably cooled basaltic melts

2020 ◽  
Author(s):  
Sarah Lang ◽  
Silvio Mollo ◽  
Lyderic France ◽  
Manuela Nazzari ◽  
Valeria Misiti ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Trace Elements ◽  
Crystal Growth ◽  
Cooling Rate ◽  
Crystallization Kinetics ◽  
Growth Rates ◽  
Crystal Surface ◽  
Major And Trace Elements ◽  
Diffusive Boundary Layer ◽  
Diffusive Boundary

<p>Olivine is an important mineral phase in naturally cooled basaltic rocks. The texture and composition of olivine are strictly related to the interplay between the degree of magma undercooling and crystal growth rate. Crystals formed at low undercoolings and growth rates generally show polyhedral-hopper textures and quite homogeneous compositions, while skeletal-dendritic textures and evident crystal zonations occur at high undercoolings and growth rates. In this context, we have performed equilibrium and disequilibrium (i.e., cooling rate) experiments to better understand, by a comparatively approach, the effects of crystallization kinetics on the incorporation of major and trace cations in olivine lattice. The experiments were carried out in a 1 atm vertical tube CO-CO2 gas-mixing furnace to perform experiment at atmospheric pressure and oxygen fugacity of QFM-2 using a basaltic glass (i.e., OIB) as starting materials. The equilibrium experiment was performed at 1175 °C. These target temperatures were kept constant for 240 h and then quenched. Conversely, the disequilibrium experiments were performed at the superliquidus temperature of 1250, and 1300 °C, which was kept constant for 2 h before cooling. The final target temperatures of 1150 (undercooling -ΔT = 50 °C), and 1175 °C (-ΔT = 25 °C) were attained by applying cooling rates of 2 °C/h, 20 °C/h, and 60 °C/h. Then the experimental charges were quenched. Results show that the olivine texture shifts from euhedral (i.e., equilibrium) to anhedral (i.e., disequilibrium) under the effect of cooling rate and rapid crystal growth. In equilibrium experiments, the composition of olivine is homogeneous and non chemical gradients are found in the melt next to the crystal surface. In contrast, a diffusive boundary layer develops in the melt surrounding the olivine crystals growing rapidly under the effect of cooling rate and degree of undercooling. The compositional gradient in the melt increases with increasing cooling rate and undercooling, causing the diffusive boundary layer to expand towards the far field melt. Because of the effects of crystallization kinetics, skeletal-dendritic olivines incorporates higher proportions of major and trace elements that are generally incompatible within their crystal lattice under equilibrium conditions.</p>

scholarly journals A microstructural dry-snow metamorphism model for kinetic crystal growth

2009 ◽  
Vol 55 (194) ◽  
pp. 1003-1011 ◽  
Author(s):  
D.A. Miller ◽  
E.E. Adams
Keyword(s):  
Mass Transfer ◽  
Temperature Gradient ◽  
Heat And Mass Transfer ◽  
Growth Rates ◽  
Crystallographic Orientation ◽  
Thermal Conditions ◽  
Crystal Habit ◽  
Large Temperature ◽  
Kinetic Growth ◽  
Snow Metamorphism

AbstractHistorically, dry-snow metamorphism has been classified by the thermal environment and thermodynamic processes in a snowpack. Snow experiencing predominantly macroscopic isothermal conditions develops different microstructure than snow subjected to large temperature gradients. As such, much previous research has been categorized by and limited to specific thermal conditions. The current research expands a generalized approach for the movement of heat and mass to include a snow crystal kinetic growth model. An existing spiral defect propagation theory for kinetic growth on simple faceted geometry is utilized. Primary crystal habit as a function of temperature is incorporated. A model of heat and mass transfer through an ice and pore structure is coupled with phase-change thermodynamics during kinetic growth. A kinetic growth microstructure model is developed and integrated into heat and mass transfer representations, which are solved using finite-difference techniques. The kinetic morphology model approximates frequently observed hopper-type crystals. The snow microstructure is allowed to change at every step, resulting in a transient description of kinetic growth metamorphism. Variable kinetic growth rates are demonstrated based on temperature and on crystallographic orientation relative to a temperature gradient. Crystals preferentially aligned with the temperature gradient have significantly higher growth rates, supporting previous observations of predominant crystal habits developing under temperature gradient conditions. Grain-size dispersion increase with time is demonstrated and supported experimentally in the literature. A dominant grain growth theory based on crystallographic orientation that has been previously postulated is supported. A broad range of metamorphic geometric parameters and thermal conditions may now be simulated with a single model.

On the prediction of crystal morphology. III. Equilibrium and growth behaviour of crystal faces containing multiple connected nets

1999 ◽  
Vol 55 (1) ◽  
pp. 84-94 ◽  
Author(s):  
R. F. P. Grimbergen ◽  
P. Bennema ◽  
H. Meekes
Keyword(s):  
Growth Rate ◽  
Monte Carlo ◽  
Growth Rates ◽  
Crystal Morphology ◽  
Crystal Habit ◽  
Growth Behaviour ◽  
Equilibrium Conditions ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Surface Phases

In this paper, the equilibrium and growth behaviour of faces (hkl) with more than one connected net is studied. It is shown that for these types of orientation different surface phases exist under equilibrium conditions as a function of temperature. Depending on the exact bonding topology at the surface, flat, rough or disordered flat phases are found. Moreover, the growth rate R_{hkl} of such faces can differ significantly from the usually calculated relative growth rates based on the attachment energy. Monte Carlo simulations confirm the results from the Hartman–Perdok analyses and offer a tool for the prediction of the crystal habit as a function of supersaturation.

scholarly journals Understanding surface interactions in aqueous miscible organic solvent treated layered double hydroxides

RSC Advances ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 5076-5083 ◽  
Author(s):  
Valentina Erastova ◽  
Matteo T. Degiacomi ◽  
Dermot O'Hare ◽  
H. Chris Greenwell
Keyword(s):  
Organic Solvent ◽  
Surface Area ◽  
Layered Double Hydroxide ◽  
Layered Double Hydroxides ◽  
Molecular Modelling ◽  
Surface Interactions ◽  
Solvent Treatment ◽  
Double Hydroxide ◽  
Double Hydroxides

Molecular modelling elucidates the mechanism of layered double hydroxide dispersion, increasing surface area, during aqueous miscible organic solvent treatment.

scholarly journals Global dynamics of a fourth-order parabolic equation describing crystal surface growth

2019 ◽  
Vol 24 (2) ◽  
pp. 159-175 ◽  
Author(s):  
Ning Duan ◽  
Xianyun Xu
Keyword(s):  
Parabolic Equation ◽  
Global Attractor ◽  
Fourth Order ◽  
Crystal Surface ◽  
Surface Growth ◽  
Global Dynamics ◽  
Initial Value ◽  
Order Parabolic Equation ◽  
Fourth Order Parabolic Equation

In this paper, we study the global dynamics for the solution semiflow of a fourth-order parabolic equation describing crystal surface growth. We show that the equation has a global attractor in H4per(Ω) when the initial value belongs to H1per(Ω).

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