scholarly journals Using Molecular Simulations to Unravel the Benefits of Characterizing Mixture Permeation in Microporous Membranes in Terms of the Spreading Pressure

ACS Omega ◽  
2020 ◽  
Vol 5 (50) ◽  
pp. 32769-32780
Author(s):  
Rajamani Krishna ◽  
Jasper M. van Baten
Keyword(s):  
Molecular Simulations ◽  
Microporous Membranes ◽  
Spreading Pressure

Split the Charge Difference in Two! a Rule of Thumb for Adding Proper Amounts of Ions in MD Simulations

2020 ◽  
Author(s):  
Matías R. Machado ◽  
Sergio Pantano
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Molecular Simulations ◽  
Md Simulations ◽  
Good Practices ◽  
Rule Of Thumb ◽  
Ionic Concentrations

<p> Despite the relevance of properly setting ionic concentrations in Molecular Dynamics (MD) simulations, methods or practical rules to set ionic strength are scarce and rarely documented. Based on a recently proposed thermodynamics method we provide an accurate rule of thumb to define the electrolytic content in simulation boxes. Extending the use of good practices in setting up MD systems is promptly needed to ensure reproducibility and consistency in molecular simulations.</p>

On the Use of Quantum Thermal Bath in Unimolecular Fragmentation Simulations

2019 ◽  
Author(s):  
Riccardo Spezia ◽  
Hichem Dammak
Keyword(s):  
Degrees Of Freedom ◽  
Molecular Simulations ◽  
Zero Point ◽  
Thermal Bath ◽  
Unimolecular Dissociation ◽  
Point Energy ◽  
Rotational Degrees Of Freedom ◽  
The Difference ◽  
Nuclear Effects

<div> <div> <div> <p>In the present work we have investigated the possibility of using the Quantum Thermal Bath (QTB) method in molecular simulations of unimolecular dissociation processes. Notably, QTB is aimed in introducing quantum nuclear effects with a com- putational time which is basically the same as in newtonian simulations. At this end we have considered the model fragmentation of CH4 for which an analytical function is present in the literature. Moreover, based on the same model a microcanonical algorithm which monitor zero-point energy of products, and eventually modifies tra- jectories, was recently proposed. We have thus compared classical and quantum rate constant with these different models. QTB seems to correctly reproduce some quantum features, in particular the difference between classical and quantum activation energies, making it a promising method to study unimolecular fragmentation of much complex systems with molecular simulations. The role of QTB thermostat on rotational degrees of freedom is also analyzed and discussed. </p> </div> </div> </div>

Microporous Membranes from an Insoluble Polyimide

1995 ◽  
Vol 60 (10) ◽  
pp. 1741-1746
Author(s):  
Jan Schauer ◽  
Miroslav Marek
Keyword(s):  
Acetic Anhydride ◽  
Phase Inversion ◽  
Amic Acid ◽  
Microporous Membranes ◽  
Inversion Process ◽  
Phase Inversion Process ◽  
Ultrafiltration Process

Poly(amic acid) prepared from 3,3',4,4'-benzophenonetetracarboxylic dianhydride and bis(4-aminophenyl) ether was used for preparation of microporous membranes by the phase inversion process. Membranes coagulated in acetic anhydride were brittle but usable for ultrafiltration. Coagulation of the poly(amic acid) in water or lower alcohols and subsequent thermal cyclocondensation led to extremely brittle polyimides, which limits their use for ultrafiltration process.

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