@book {635, title = {ACS Symposium SeriesGels and Other Soft Amorphous Solids Heterogeneity in Cement Hydrates}, volume = {1296}, year = {2018}, pages = {357-371}, publisher = {American Chemical Society}, organization = {American Chemical Society}, address = {Washington, DC}, abstract = {

Cement hydrates named C-S-H are the main products of the reaction of cement with water. The C-S-H phase is the most important phase of cement paste as it glues all other phases together in a solid rock-like material. C-S-H gels form and densify via out-of-equilibrium precipitation and aggregation of nano-grains during cement hydration. In this chapter, the link between the making and densification of C-S-H gels and amorphous solids is discussed by coarse-grained models based on the evolution of interaction potentials and an out-of-equilibrium simulation approach for particle precipitation. In particular, we characterize and correlate mesoscale structural and mechanical heterogeneities resulting into residual local eigenstresses. This underlying microscopic picture explains recent macroscopic measurements of the volume change of hydrating cement in fully saturated conditions.

}, isbn = {0-8412-3316-0}, issn = {0097-6156}, doi = {10.1021/symposium10.1021/bk-2018-129610.1021/bk-2018-1296.ch018}, url = {http://pubs.acs.org/series/symposiumhttp://pubs.acs.org/doi/book/10.1021/bk-2018-1296}, author = {Katerina Ioannidou}, editor = {Horkay, Ferenc and Douglas, Jack F. and Emanuela Del Gado} } @article {534, title = {Atomistic and mesoscale simulation of sodium and potassium adsorption in cement paste}, journal = {The Journal of Chemical Physics}, volume = {14963}, year = {2018}, month = {Aug-21-2018}, pages = {074705}, abstract = {

An atomistic and mesoscopic assessment of the effect of alkali uptake in cement paste is performed. Semi-grand canonical Monte Carlo simulations indicate that Na and K not only adsorb at the pore surface of calcium silicate hydrates (C-S-H) but also adsorb in the C-S-H hydrated interlayer up to concentrations of the order of 0.05 and 0.1 mol/kg, respectively. Sorption of alkali is favored as the Ca/Si ratio of C-S-H is reduced. Long timescale simulations using the Activation Relaxation Technique indicate that characteristic diffusion times of Na and K in the C-S-H interlayer are of the order of a few hours. At the level of individual grains, Na and K adsorption leads to a reduction of roughly 5\% of the elastic moduli and to volume expansion of about 0.25\%. Simulations using the so-called primitive model indicate that adsorption of alkali ions at the pore surface can reduce the binding between C-S-H grains by up to 6\%. Using a mesoscopic model of cement paste, the combination of individual grain swelling and changes in inter-granular cohesion was estimated to lead to overall expansive pressures of up to 4 MPa\—and typically of less than 1 MPa\—for typical alkali concentrations observed at the proximity of gel veins caused by the alkali-silica reaction.

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}, issn = {0021-9606}, doi = {10.1063/1.5042755}, url = {https://aip.scitation.org/doi/10.1063/1.5042755}, author = {Dufresne, Alice and Arayro, Jack and Zhou, Tingtao and Katerina Ioannidou and Franz-Josef Ulm and Roland Jean-Marc Pellenq and B{\'e}land, Laurent Karim} } @article {624, title = {Accurate classical short-range forces for the study of collision cascades in Fe{\textendash}Ni{\textendash}Cr}, journal = {Computer Physics Communications}, volume = {219}, year = {2017}, month = {Oct-2017}, pages = {11 - 19}, abstract = {

The predictive power of a classical molecular dynamics simulation is largely determined by the physical validity of its underlying empirical potential. In the case of high-energy collision cascades, it was recently shown that correctly modeling interactions at short distances is necessary to accurately predict primary damage production. An ab initio based framework is introduced for modifying an existing embedded-atom method FeNiCr potential to handle these short-range interactions. Density functional theory is used to calculate the energetics of two atoms approaching each other, embedded in the alloy, and to calculate the equation of state of the alloy as it is compressed. The pairwise terms and the embedding terms of the potential are modified in accordance with the ab initio results. Using this reparametrized potential, collision cascades are performed in Ni50Fe50, Ni80Cr20 and Ni33Fe33Cr33. The simulations reveal that alloying Ni and NiCr to Fe reduces primary damage production, in agreement with some previous calculations. Alloying Ni and NiFe to Cr does not reduce primary damage production, in contradiction with previous calculations.

}, issn = {00104655}, doi = {10.1016/j.cpc.2017.05.001}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0010465517301315}, author = {B{\'e}land, Laurent Karim and Tamm, Artur and Mu, Sai and Samolyuk, D. and Osetsky, N. and Aabloo, Alvo and Klintenberg, Mattias and Caro, Alfredo and Stoller, E.} } @article {639, title = {Activated desorption at heterogeneous interfaces and long-time kinetics of hydrocarbon recovery from nanoporous media}, journal = {Nature Communications}, volume = {7}, year = {2016}, month = {Jun-2016}, pages = { Article Number 11890 }, abstract = {

Hydrocarbon recovery from unconventional reservoirs (shale gas) is debated due to its environmental impact and uncertainties on its predictability. But a lack of scientific knowledge impedes the proposal of reliable alternatives. The requirement of hydrofracking, fast recovery decay and ultra-low permeability-inherent to their nanoporosity-are specificities of these reservoirs, which challenge existing frameworks. Here we use molecular simulation and statistical models to show that recovery is hampered by interfacial effects at the wet kerogen surface. Recovery is shown to be thermally activated with an energy barrier modelled from the interface wetting properties. We build a statistical model of the recovery kinetics with a two-regime decline that is consistent with published data: a short time decay, consistent with Darcy description, followed by a fast algebraic decay resulting from increasingly unreachable energy barriers. Replacing water by CO2 or propane eliminates the barriers, therefore raising hopes for clean/efficient recovery.

}, doi = {10.1038/ncomms11890}, url = {http://www.nature.com/articles/ncomms11890}, author = {Lee, Thomas and Lyd{\'e}ric Bocquet and Benoit A. Coasne} } @article {637, title = {Adsorption in heterogeneous porous media: Hierarchical and composite solids}, journal = {Microporous and Mesoporous Materials}, volume = {229}, year = {2016}, month = {Jul-15-2016}, pages = {145 - 154}, abstract = {

Experiment and molecular simulation are used to investigate adsorption in heterogeneous porous media consisting of hierarchical solids (combining different porosity scales) or composite solids (such as silver nanoparticles adsorbed at the external surface of zeolite). It is shown that adsorption in such heterogeneous materials can be written as a linear combination of the adsorption isotherms in its different domains (i.e. porosity scales for the hierarchical sample and constituents for the composite sample). In the case of the composite material, we also show that the linear combination can be used with weighing parameters obtained for a different adsorbate. Such a superimposition principle, which is validated using well-characterized experimental samples, is of interest for characterization purpose as well as industrial applications as they can be used to determine accurately the amount of phases in a given sample (volume corresponding to a given porosity scale or constituent). In contrast, significant departure between the experimental adsorption isotherm and the linear combination can be used to detect coupling effects between the different domains or restrained access to a given domain type. Such a characterization strategy of complex heterogeneous media is complementary to other experiments, such as those probing capillary hysteresis shapes, scanning curves and subloops, which allow determining the distribution of domains within the framework of the independent domain theory. (C) 2016 Elsevier Inc. All rights reserved.

}, issn = {13871811}, doi = {10.1016/j.micromeso.2016.04.011}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1387181116301032}, author = {Deliere, Ludovic and Fran{\c c}ois Villemot and David Farrusseng and Anne Galarneau and Topin, Sylvain and Benoit A. Coasne} } @article {179, title = {Advances in design and modeling of porous materials}, journal = {The European Physical Journal Special Topics}, volume = {224}, year = {2015}, month = {Jul-2015}, pages = {1653 - 1653}, abstract = {

This special issue of the European Physical Journal Special Topics is dedicated to selected papers from the symposium \“High surface area porous and granular materials\” organized in the frame of the conference \“Mat\ériaux 2014\”, held on November 24\–28, 2014 in Montpellier, France.

Porous materials and granular materials gather a wide variety of heterogeneous, isotropic or anisotropic media made of inorganic, organic or hybrid solid skeletons, with open or closed porosity, and pore sizes ranging from the centimeter scale to the sub-nanometer scale. Their technological and industrial applications cover numerous areas from building and civil engineering to microelectronics, including also metallurgy, chemistry, health, waste water and gas effluent treatment. Many emerging processes related to environmental protection and sustainable development also rely on this class of materials. Their functional properties are related to specific transfer mechanisms (matter, heat, radiation, electrical charge), to pore surface chemistry (exchange, adsorption, heterogeneous catalysis) and to retention inside confined volumes (storage, separation, exchange, controlled release). The development of innovative synthesis, shaping, characterization and modeling approaches enables the design of advanced materials with enhanced functional performance. The papers collected in this special issue offer a good overview of the state-of-the-art and science of these complex media.

We would like to thank all the speakers and participants for their contribution to the success of the symposium. We also express our gratitude to the organization committee of \“Mat\´eriaux 2014\”. We finally thank the reviewers and the staff of the European Physical Journal Special Topics who made the publication of this special issue possible.

}, issn = {1951-6355}, doi = {10.1140/epjst/e2015-02487-6}, author = {Ayral, Andre and Calas-Etienne, Sylvie and Benoit A. Coasne and Deratani, Andr{\'e} and Evstratov, Alexis and Anne Galarneau and Grande, Daniel and Hureau, Matthieu and Jobic, Herv{\'e} and Morlay, Catherine and Parmentier, Julien and Prelot, B{\'e}n{\'e}dicte and Rossignol, Sylvie and Simon-Masseron, Ang{\'e}lique and Thibault-Starzyk, Fr{\'e}d{\'e}ric} } @article {177, title = {Assessing Polarizability Models for the Simulation of Low-Frequency Raman Spectra of Benzene}, journal = {The Journal of Physical Chemistry B}, volume = {119}, year = {2015}, month = {Jul-23-2015}, pages = {9345 - 9358}, abstract = {
Abstract Image

Optical Kerr effect (OKE) spectroscopy is a widely used technique for probing the low-frequency, Raman-active dynamics of liquids. Although molecular simulations are an attractive tool for assigning liquid degrees of freedom to OKE spectra, the accurate modeling of the OKE and the motions that contribute to it relies on the use of a realistic and computationally tractable molecular polarizability model. Here we explore how the OKE spectrum of liquid benzene, and the underlying dynamics that determines its shape, are affected by the polarizability model employed. We test a molecular polarizability model that uses a point anisotropic molecular polarizability and three other models that distribute the polarizability over the molecule. The simplest and most computationally efficient distributed polarizability model tested is found to be sufficient for the accurate simulation of the many-body polarizability dynamics of this liquid. We further find that the atomic-to-molecular polarizability transformation approximation [Hu et al. J. Phys. Chem. B 2008, 112, 7837\–7849], used in conjunction with this distributed polarizability model, yields OKE spectra whose shapes differ negligibly from those calculated without this approximation, providing a substantial increase in computational efficiency.

}, issn = {1520-6106}, doi = {10.1021/jp509968v}, author = {Bender, John S. and Benoit A. Coasne and Fourkas, John T.} } @article {108, title = {Adsorption and Dynamics in Hierarchical Metal-Organic Frameworks}, journal = {Journal of Physical Chemistry C}, volume = {118}, year = {2014}, month = {Apr-10-2014}, pages = {7423-7433}, type = {Article}, abstract = {

Adsorption and dynamics in hierarchical metal-organic frameworks are investigated by means of molecular simulation. The models of hierarchical porous solids are obtained by carving mesopores of different diameters out of a crystal of Cu-BTC (model A) or by inserting a microporous particle of Cu-BTC in an amorphous silica mesopore (model B). We show that the nitrogen adsorption isotherms at 77 K for the solids corresponding to model A can be described as a linear combination of reference adsorption isotherms for pure microporous and mesoporous solids. In contrast, the adsorption isotherms for model B cannot be described accurately as a sum of reference microporous and mesoporous adsorption isotherms. The inserted particle acts as a constriction which helps nucleate the liquid phase within the mesopore so that no capillary condensation hysteresis is observed. The dynamics of nitrogen adsorbed at 77 K inside the porosity of the hierarchical solids is also investigated. The Fickian regime is reached at long times which are not attainable with molecular dynamics simulations. At higher temperature, the faster self-diffusion makes it possible to obtain the diffusivity of the adsorbate. Nitrogen adsorbed in the microporosity of the hierarchical porous solids has a self-diffusion coefficient close to that of nitrogen adsorbed in pure Cu-BTC. In contrast, diffusion in the mesoporosity is faster than in the microporosity so that the overall diffusivity is faster than in pure Cu-BTC.

\<\>Abstract Image

}, issn = {1932-7447}, doi = {10.1021/jp500037z}, author = {Fran{\c c}ois Villemot and Anne Galarneau and Benoit A. Coasne} } @article {80, title = {Adsorption of carbon dioxide-methane mixtures in porous carbons: effect of surface chemistry}, journal = {Adsorption-Journal fo the International Adsorption Society}, volume = {20}, year = {2014}, month = {Feb-2014}, pages = {453-463}, type = {Article}, abstract = {

A combined experimental and molecular simulation study of the coadsorption of CO2 and CH4 in porous carbons is reported. We address the effect of surface chemistry by considering a numerical model of disordered porous carbons which has been modified to include heterochemistry (with a chemical composition consistent with that of the experimental sample). We discuss how realistic the numerical sample is by comparing its pore size distribution (PSD), specific surface area, porous volume, and porosity with those for the experimental sample. We also discuss the different criteria used to estimate the latter properties from a geometrical analysis. We demonstrate the ability of the MP method to estimate PSD of porous carbons from nitrogen adsorption isotherms. Both the experimental and simulated coadsorption isotherms resemble those obtained for pure gases (type I in the IUPAC classification). On the other hand, only the porous carbon including the heterogroups allows simulating quantitatively the selectivity of the experimental adsorbent for different carbon dioxide/methane mixtures. This result shows that taking into account the heterochemistry present in porous carbons is crucial to represent correctly adsorption selectivities in such hydrophobic samples. We also show that the adsorbed solution theory describes quantitatively the simulated and experimental coadsorption isotherms without any parameter adjustment.

}, keywords = {Carbon dioxide, Methane, Mixtures, Porous carbons}, issn = {0929-5607}, doi = {10.1007/s10450-013-9570-z}, author = {Pierre Billemont and Benoit A. Coasne and Guy De Weireld} } @article {64, title = {Adsorption-based characterization of hierarchical metal{\textendash}organic frameworks}, journal = {Adsorption}, volume = {20}, year = {2014}, month = {Feb-2014}, pages = {349-357}, abstract = {

Nitrogen adsorption at 77 K on metal\–organic framework (MOF) is investigated by means of molecular simulations. We consider both regular Cu\–BTC crystal and a MOF-based hierarchical porous solid consisting of a mesopore carved out of a Cu\–BTC crystal. The t-plot method is applied to these solids by using a non-porous Cu\–BTC surface as the reference sample. The values of the mesoporous and external surface areas are determined from the t-plot, and the validity of the method for this type of hierarchical solid is discussed.

}, keywords = {Adsorption, Hierarchical porous materials, Molecular simulation, t-Plot}, issn = {0929-5607}, doi = {10.1007/s10450-013-9583-7}, author = {Fran{\c c}ois Villemot and Anne Galarneau and Benoit A. Coasne} } @article {102, title = {Anomalous composition-dependent dynamics of nanoconfined water in the interlayer of disordered calcium-silicates}, journal = {Journal of Chemical Physics}, volume = {140}, year = {2014}, month = {Feb-07-2014}, pages = {Article Number: 054515}, type = {Article}, abstract = {

With shear interest in nanoporous materials, the ultraconfining interlayer spacing of calcium-silicate-hydrate (C-S-H) provides an excellent medium to study reactivity, structure, and dynamic properties of water. In this paper, we present how substrate composition affects chemo-physical properties of water in ultraconfined hydrophilic media. This is achieved by performing molecular dynamics simulation on a set of 150 realistic models with different compositions of calcium and silicon contents. It is demonstrated that the substrate chemistry directly affects the structural properties of water molecules. The motion of confined water shows a multi-stage dynamics which is characteristic of supercooled liquids and glassy phases. Inhomogeneity in that dynamics is used to differentiate between mobile and immobile water molecules. Furthermore, it is shown that the mobility of water molecules is composition-dependent. Similar to the pressure-driven self-diffusivity anomaly observed in bulk water, we report the first study on composition-driven diffusion anomaly, the self diffusivity increases with increasing confined water density in C-S-H. Such anomalous behavior is explained by the decrease in the typical activation energy required for a water molecule to escape its dynamical cage. (C) 2014 AIP Publishing LLC.

Image of FIG. 1.
Image of FIG. 2.
Image of FIG. 3.
}, issn = {0021-9606}, doi = {10.1063/1.4864118}, author = {Mohammad Javad Abdolhosseini Qomi and Mathieu Bauchy and Franz-Josef Ulm and Roland Jean-Marc Pellenq} } @article {107, title = {An artificial primitive mimic of the Gramicidin-A channel}, journal = {Nature Communications}, volume = {5}, year = {2014}, month = {Jun-26-2014}, type = {Article}, abstract = {

Gramicidin A (gA) is the simplest known natural channel, and important progress in improving conduction activity has previously been obtained with modified natural gAs. However, simple artificial systems mimicking the gA functions are unknown. Here we show that gA can be mimicked using a simple synthetic triazole or {\textquoteleft}T-channel\&$\#$39; forming compound (TCT), having similar constitutional functions as the natural gAs. As in gA channels, the carbonyl moieties of the TCT, which point toward the T-channel core and surround the transport direction, are solvated by water. The net-dipolar alignment of water molecules along the chiral pore surfaces influences the conduction of protons/ions, envisioned to diffuse along dipolar hydrophilic pathways. Theoretical simulations and experimental assays reveal that the conduction through the T-channel, similar to that in gA, presents proton/water conduction, cation/anion selectivity and large open channel-conductance states. T-channels-associating supramolecular chirality with dipolar water alignment-represent an artificial primitive mimic of gA.

Molecular structures and crystal packing.

Molecular simulations of water molecules and ions confined within T-channel.

Bilayer membrane transport experiments.

Single channel conductance of T-channels under {\textquoteleft}early stage{\textquoteright} conductance records.

}, issn = {2041-1723}, doi = {10.1038/ncomms5142}, author = {Barboiu, Mihail and Le Duc, Yann and Gilles, Arnaud and Pierre-Andre Cazade and Michau, Mathieu and Yves-Marie Legrand and Arie Van Der Lee and Benoit A. Coasne and Parvizi, Paria and Post, Joshua and Fyles, Thomas} } @article {84, title = {Atomic-scale modelling of elastic and failure properties of clays}, journal = {Molecular Physics}, volume = {112}, year = {2014}, month = {May-19-2014}, pages = {1294-1305}, type = {Article}, abstract = {

The elastic and failure properties of a typical clay, illite, are investigated using molecular simulation. We employ a reactive (ReaxFF) and a non-reactive (ClayFF) force field to assess the elastic properties of the clay. As far as failure is concerned, ReaxFF was used throughout the study; however, some calculations were also performed with ClayFF. A crack parallel to the clay layers is found to have low fracture resistance when submitted to a tensile loading perpendicular to the crack. The mechanism of both yield and fracture failures is decohesion in the interlayer space. In contrast, under shear loading, the nanoscale failure mechanism is a stick-slip between clay layers. No fracture propagation is observed as the clay layers slide on top of each other. The low fracture resistance in mode I and the stick-slip failure in mode II are both the consequence of the lack of chemical bonds between clay layers where the cohesion is provided by non-covalent interactions. This work, which provides a description of the failure of clays at the microscopic scale, is the first step towards describing the failure of clays at a larger scale where the polycrystalline distribution of clay grains must be taken into account.

}, keywords = {clay, elastic properties, fracture, reactive molecular simulation}, issn = {0026-8976}, doi = {10.1080/00268976.2014.897393}, author = {Gy{\"o}rgy Hantal and Brochard, Laurent and Hadrien Laubie and Ebrahimi, Davoud and Roland Jean-Marc Pellenq and Franz-Josef Ulm and Benoit A. Coasne} } @article {39, title = {An atomistic modeling of the xenon bubble behavior in the UO2 matrix}, journal = {Journal of Nuclear Materials}, volume = {444}, year = {2014}, month = {Jan-2014}, pages = {153{\textendash}160}, abstract = {

The behavior of the xenon nanoinclusions/bubbles in the uranium dioxide (UO2) matrix and their influence on its swelling were investigated through atomistic simulation techniques. The pressure in bubbles of less than 2\ nm in diameter, calculated using a virial equation that takes into account the xenon/matrix interactions, is larger than the pressure calculated in simulations of the equivalent density and temperature of super critical bulk xenon. The radial distribution function of confined xenon is characteristic of a dense (\ \>\ 4\ g/cm3) glassy phase. The swelling of the UO2 induced by the intragranular bubbles is proportional to the Xe/U ratio but independent of the temperature.

The UO2 elementary cell. It contains 4 uranium atoms (large spheres) forming a ...

Comparison between the density versus pressure ρ(P) curves calculated at 298K ...

Comparison between the bulk modulus versus pressure K(P) curves calculated at ...

}, doi = {10.1016/j.jnucmat.2013.09.041}, author = {Andrei Jelea and Roland Jean-Marc Pellenq and F. Ribeiro} } @article {95, title = {Adsorption, intrusion and freezing in porous silica: the view from the nanoscale}, journal = {Chemical Society Reviews}, volume = {42}, year = {2013}, month = {Jan-24-2013}, pages = {4141-4171}, type = {Review}, abstract = {

This review presents the state of the art of molecular simulation and theory of adsorption, intrusion and freezing in porous silica. Both silica pores of a simple geometry and disordered porous silicas which exhibit morphological and topological disorders are considered. We provide a brief description of the numerical models of porous silicas available in the literature and present the most common molecular simulation and theoretical methods. Adsorption in regular and irregular pores is discussed in the light of classical theories of adsorption and capillary condensation in pores. We also present the different evaporation mechanisms for disordered systems: pore blocking and cavitation. The criticality of fluids confined in pores, which is still the matter of debate, is then discussed. We review theoretical results for intrusion/extrusion and freezing in silica pores and discuss the validity of classical approaches such as the Washburn-Laplace equation and Gibbs-Thomson equation to describe the thermodynamics of intrusion and in-pore freezing. The validity of the most widely used characterization techniques is then discussed. We report some concluding remarks and suggest directions for future work.

Graphical abstract: Adsorption, intrusion and freezing in porous silica: the view from the nanoscale

}, issn = {0306-0012}, doi = {10.1039/c2cs35384a}, author = {Benoit A. Coasne and Anne Galarneau and Roland Jean-Marc Pellenq and Di Renzo, Francesco} } @article {35, title = {Adsorption of Aromatic Hydrocarbon Molecules at the Surface of Ice, As Seen by Grand Canonical Monte Carlo Simulation}, journal = {The Journal of Physical Chemistry C}, volume = {117}, year = {2013}, month = {Apr-2013}, pages = {6719{\textendash}6729}, abstract = {
Abstract Image

The adsorption of four aromatic hydrocarbon compounds, benzene, naphthalene, anthracene, and phenanthrene, at the surface of Ih ice is investigated by grand canonical Monte Carlo (GCMC) computer simulation under tropospheric conditions at 200 K. By systematic variation of the value of adsorbate chemical potential in the simulations, the adsorption isotherms are determined. It is found that adsorption follows the Langmuir mechanism only up to a rather low relative pressure value in every case. In this range specific surface sites, called \α sites, to which adsorbate molecules can be bound particularly strongly in specific orientation, are occupied. In these \α sites, presumably the dangling OH bonds of the ice surface form O\–H....\π-type hydrogen bonds with the delocalized \π electrons of the adsorbed aromatic molecule lying parallel with the ice surface. Once these \α sites are saturated, lateral interactions become increasingly important, leading to large fluctuations of the lateral density of the adsorption layer and an increasing deviation of the adsorption isotherm from the Langmuir shape. The adsorption layer is found to be strictly monomolecular and even unsaturated in every case, as condensation well precedes the saturation of this monolayer for all four aromatic adsorbates considered in this study.

}, doi = {10.1021/jp401532x}, author = {M{\'e}sz{\'a}r, Zsuzsanna E and Gy{\"o}rgy Hantal and Picaud, Sylvain and Jedlovszky, P{\'a}l} } @article {42, title = {Adsorption of carbon dioxide, methane, and their mixtures in porous carbons: effect of surface chemistry, water content, and pore disorder}, journal = {Langmuir}, volume = {29}, year = {2013}, month = {Jan-2013}, pages = {3328{\textendash}3338}, abstract = {
Abstract Image

The adsorption of carbon dioxide, methane, and their mixtures in nanoporous carbons in the presence of water is studied using experiments and molecular simulations. Both the experimental and numerical samples contain polar groups that account for their partially hydrophilicity. For small amounts of adsorbed water, although the shape of the adsorption isotherms remain similar, both the molecular simulations and experiments show a slight decrease in the CO2 and CH4 adsorption amounts. For large amounts of adsorbed water, the experimental data suggest the formation of methane or carbon dioxide clathrates in agreement with previous work. In contrast, the molecular simulations do not account for the formation of such clathrates. Another important difference between the simulated and experimental data concerns the number of water molecules that desorb upon increasing the pressure of carbon dioxide and methane. Although the experimental data indicate that water remains adsorbed upon carbon dioxide and methane adsorption, the molecular simulations suggest that 40 to 75\% of the initial amount of adsorbed water desorbs with carbon dioxide or methane pressure. Such discrepancies show that differences between the simulated and experimental samples are crucial to account for the rich phase behavior of confined water\–gas systems. Our simulations for carbon dioxide\–methane coadsorption in the presence of water suggest that the pore filling is not affected by the presence of water and that adsorbed solution theory can be applied for pressures as high as 15 MPa.

}, doi = {10.1021/la3048938}, author = {Pierre Billemont and Benoit A. Coasne and Guy De Weireld} } @article {24, title = {Adsorption of Volatile Organic Compounds in pure silica CHA, *BEA, MFI and STT-type zeolites}, journal = {Microp. Mesop. Mater.}, volume = {173}, year = {2013}, month = {Jun-2013}, pages = {147{\textendash}154}, abstract = {

Four pure silica zeolites, chabazite (CHA-structure type) and SSZ-23 (STT-structure type) with cage-like structure and silicalite-1 (MFI-structure type) and beta (\∗BEA-structure type) with channel structure, were synthesized and fully characterized. Their sorption properties were examined using gravimetric method combined with Grand Canonical Monte Carlo simulations (GCMC). Of particular interest is the large difference in the adsorption rates of n-hexane, p-xylene and acetone observed for these zeosils at 25, 75 and 150\ \°C. As expected, in most cases, a decrease in the adsorption capacity is observed with increasing the molar volume of the used probe molecule and the temperature. An exception is observed for the pure silica CHA-type zeolite due to its small pore size which prevents molecules from entering its porosity. However, at higher temperature, the window size widens slightly and allows n-hexane and acetone, which have kinetic diameter close to the pore opening, to enter easily in chabazite. As a result, for this zeosil, an increase in the adsorption capacity compared to that obtained at 25\ \°C is observed. All these zeosils are promising for technological uses in car exhaust gas decontamination.

Image for unlabelled figure

}, doi = {10.1016/j.micromeso.2013.02.009}, author = {A. F. Cosseron and T. J. Daou and L. Tzanis and H. Nouali and I. Deroche and Benoit A. Coasne and V. Tchaber and J. Patarin} } @article {81, title = {Adsorption-based characterization of hierarchical metal-organic frameworks}, journal = {Adsorptio-Journal of the International Adsorption Society}, volume = {20}, year = {2013}, month = {Oct-06-2013}, pages = {349-357}, type = {Article}, abstract = {

Nitrogen adsorption at 77 K on metal-organic framework (MOF) is investigated by means of molecular simulations. We consider both regular Cu-BTC crystal and a MOF-based hierarchical porous solid consisting of a mesopore carved out of a Cu-BTC crystal. The t-plot method is applied to these solids by using a non-porous Cu-BTC surface as the reference sample. The values of the mesoporous and external surface areas are determined from the t-plot, and the validity of the method for this type of hierarchical solid is discussed.

}, keywords = {Adsorption, Hierarchical porous materials, Molecular simulation, t-Plot}, issn = {0929-5607}, doi = {10.1007/s10450-013-9583-7}, author = {Fran{\c c}ois Villemot and Anne Galarneau and Benoit A. Coasne} } @proceedings {365, title = {AIP Conference Proceedings A multiscale description of failure in granular materials}, journal = {7th International Conference on Micromechanics of Granular Media (Powders and Grains)}, volume = {Book Series: AIP Conference Proceedings POWDERS AND GRAINS 2013}, year = {2013}, month = {Jun-18-2013}, pages = {585-588}, publisher = {AIP}, address = {JUL 08-12 2013 Sydney, AUSTRALIA}, abstract = {

This paper presents conditions of initiation and development of failure in granular materials through a twodimensional discrete element model. General condition for the effective development of failure and its physical characteristics are recalled. Then relation between failure and the second order work expressed in terms of microscopic variables is discussed. Eventually, correspondence between a localized mode of failure marked with shear band patterns and space distribution of negative values of microscopic second-order work is investigated.

}, doi = {10.1063/1.4811999}, author = {Hadda, Nejib and Fran{\c c}ois Nicot and Sibille, Luc and Farhang Radja{\"\i} and Tordesillas, Antoinette and Darve, F{\'e}lix}, editor = {Yu, A and Dong, K and Yang, R} } @proceedings {366, title = {AIP Conference ProceedingsTumbling sandpiles in a fluid}, journal = {7th International Conference on Micromechanics of Granular Media (Powders and Grains)}, volume = {Book Series: AIP Conference Proceedings POWDERS AND GRAINS 2013}, year = {2013}, month = {Jul-2013}, pages = {662-665}, publisher = {AIP}, address = {JUL 08-12 2013 Sydney, AUSTRALIA}, abstract = {

By means of contact dynamics simulations interfaced with computational fluid dynamics, we analyze the effect of a suspending fluid on the dynamics of collapse and spread of a granular column. We find that the runout distance increases as a power law with the aspect ratio of the column and, for a given aspect ratio, it may be the same in the grain-inertial and fluid-inertial regimes but with considerably longer duration in the latter case. We show that, in both viscous and fluid-inertial regimes, this behavior results from compensation between two effects of the fluid: 1) reduction of the kinetic energy during collapse and 2) enhancement of the flow by lubrication during spread.

}, doi = {10.1063/1.4812018}, author = {Farhang Radja{\"\i} and Vincent Topin and Perales, F. and Yann Monerie}, editor = {Yu, A and Dong, K and Yang, R} } @article {59, title = {Adsorption-induced deformation of microporous materials: coal swelling induced by co2{\textendash}ch4 competitive adsorption}, journal = {Langmuir}, volume = {28}, year = {2011}, month = {Dec-20-2011}, pages = {2659{\textendash}2670}, abstract = {
Abstract Image

Carbon dioxide injection in coal seams is known to improve the methane production of the coal seam, while ensuring a safe and long-term carbon sequestration. This improvement is due to the preferential adsorption of CO2 in coal with respect to CH4: an injection of CO2 thus results in a desorption of CH4. However, this preferential adsorption is also known to cause a differential swelling of coal, which results in a significant decrease in the reservoir permeability during the injection process. Recent studies have shown that adsorption in coal micropores (few angstr\öms in size) is the main cause of the swelling. In this work, we focus on the competitive adsorption behavior of CO2 and CH4 in micropores. We perform molecular simulations of adsorption with a realistic atomistic model for coal. The competitive adsorption is studied at various temperatures and pressures representative of those in geological reservoirs. With the help of a poromechanical model, we then quantify the subsequent differential swelling induced by the computed adsorption behaviors. The differential swelling is almost insensitive to the geological temperatures and pressures considered here and is proportional to the CO2 mole fraction in the coal.

}, doi = {10.1021/la204072d}, author = {Brochard, Laurent and Matthieu Vandamme and Roland Jean-Marc Pellenq and Fen-Chong, Teddy} } @article {289, title = {An atomistic modelling of the porosity impact on UO2 matrix macroscopic properties}, journal = {Journal of Nuclear Materials}, volume = {415}, year = {2011}, month = {Aug-15-2011}, pages = {210 - 216}, abstract = {

The porosity impact on the UO2 matrix thermomechanical properties was investigated using atomistic simulation techniques. The porosity modifies the thermal expansion coefficient and this is attributed to pore surface effects. The elastic moduli at 0\ K and at finite temperature decrease with porosity, this variation being well approximated using affine functions. These results agree with other mesoscale model predictions and experimental data, showing the ability of the semiempirical potential atomistic simulations to give an overall good description of the porous UO2. However, the surface effects are incompletely described.

Fig. 1. The UO2 elementary cell contains 12 atoms: 4 uranium atoms (large spheres){\textellipsis}

fig.=

Fig. 3. Example of 6{\texttimes}6{\texttimes}6 one pore relaxed supercells of different pore radius (4, 6 and{\textellipsis}

Fig. 4. One layer of UO2 as considered in the present work: top {\textendash} the (100){\textellipsis}

Fig. 5. Variation of the UO2 thermal expansion coefficient versus temperature: top {\textendash}{\textellipsis}

Fig. 6. Variation of the shear modulus (G) and Young{\textquoteright}s modulus (E) versus porosity at 0K

}, issn = {00223115}, doi = {10.1016/j.jnucmat.2011.06.006}, author = {Andrei Jelea and Colbert, M. and F. Ribeiro and G. Tr{\'e}glia and Roland Jean-Marc Pellenq} }