1,721,386 research outputs found
Evaluating mixture adsorption models using molecular simulation
Get PDFThe design of adsorption-based separation processes using novel adsorbents requires reliable data for the adsorption of fluid mixtures on candidate adsorbents. Due to the difficulty of generating sufficient data across possible operating conditions, process designs generally rely on interpolation of pure-component data using a model, most commonly ideal adsorbed solution theory (IAST), and related theories. There are many cases where IAST fails to provide an adequate description of mixture adsorption, usually due to the fact that practical adsorbents do not have uniform surfaces. We have evaluated the use of a segregated version of IAST, where competition is assumed to occur at isolated adsorption sites. This simple modification can provide the correct description of adsorption across a large range of pressures using ideal isotherm models. We also demonstrate the importance of identifying multiple sites even for weakly adsorbing components to provide the correct behavior at high pressure. (c) 2013 American Institute of Chemical Engineers AIChE J, 59: 3054-3064, 201
Adsorption and diffusion in zeolites: the pitfall of isotypic crystal structures
Get PDFLSMOZimmermann, Nils E. R. Haranczyk, Maciej Sharma, Manju Liu, Bei Smit, Berend Keil, Frerich J
Theoretical Simulation of n-Alkane Cracking on Zeolites
Get PDFLSMOSwisher, Joseph A. Hansen, Niels Maesen, Theo Keil, French J. Smit, Berend Bell, Alexis T
Shape-selective n-alkane hydroconversion at exterior zeolite surfaces
Get PDFLSMOMaesen, Theo L. M. Krishna, Rajamani van Baten, Jasper M. Smit, Berend Calero, Sofia Castillo Sanchez, Juan Manue
Addressing Challenges of Identifying Geometrically Diverse Sets of Crystalline Porous Materials
Get PDFLSMOMartin, Richard Luis Smit, Berend Haranczyk, Maciej9th International Conference on Chemical Structures (ICCS)Jun 05-09, 2011Noordwijkerhout, NETHERLAND
Understanding & Application Driven Design of Metal-Organic Frameworks for Carbon Capture
No full textLSMOSB-SCG
Synergy of classical and quantum computational methods to investigate the properties of microporous materials
Get PDFThe aim of this thesis is to explore the power and the limits of classical and quantum molecular modelling, for the investigation of the adsorption properties of microporous crystalline materials. The materials analyzed are metal organic frameworks (MOFs) and covalent organic frameworks (COFs), two classes of frameworks that in the last two decades attracted the interest of the scientific community due to their limitless possibility of tunability and their remarkable properties. The four articles that are gathered in this document describe the advances in (1) modelling the interaction of polar molecules with MOFs' open metal sites, (2) computing the micorpore volume that can be occupied by gas molecules, (3) benchmarking the different protocols that are used to estimate partial charges in the frameworks and (4) constructing a full workflow to evaluate the performance of COFs for carbon capture and storage, from just their crystal structure.LSM
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Molecular Simulations of Lipid Bilayers and Membrane Helices Interactions
Get PDFIn this work we use mesoscopic simulation to investigate the short and medium range interaction of transmembrane helices. First, we develop a coarse-grained model of a generic transmembrane α-helix. We use the geometry constraints of an α-helix, along with a set of homogeneous hydrophobic beads. We discuss the reasoning behind this modeling and why various other plausible models have failed in describing the short-range interactions of transmembrane helices. We then show the effect of hydrophobic mismatch on these model helices. The tilt angle of a single helix is affected by its hydrophobic mismatch with the surrounding bilayer. We show that the hydrophobic mismatch, via its effect on the tilt angle, has a crucial effect on the cross angle of two packed transmembrane helices as well. We further show the effect of hydrophobic mismatch on the potential of mean force between the helices as well as on the thickness and tilt angle of the lipids surrounding the helices. We introduce a class of especially long helices, termed super-positive mismatched helices, to which the response of the lipids differs and discuss the origin of this behavior. These coarse-grained simulations are performed using the Dissipative Particle Dynamics (DPD) scheme Performing large time and length scale simulations using this scheme is highly CPU-time consuming. To enhance our simulation capabilities we develop a novel, massively parallel simulation algorithm. We introduce this algorithm and the original concepts we developed for parallelizing the DPD scheme. We show that this novel approach provides up to 30 times speed up on a Graphical Processing Unit (GPU) over the non-parallel CPU version. Finally, we use our parallel algorithm to perform simulation on a large time and length scale system. We investigate the effect of Cholesterol on the bending rigidity of lipid bilayers and show the effect of a phase transition on the bending modulus. Extracting the bending modulus from simulation requires a large system that enables long-range height fluctuations. Using a fast, parallel simulation algorithm for such a task is therefore crucial
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