Article
Polymer Science
Anastassia Rissanou, Antonis Chazirakis, Patrycja Polinska, Craig Burkhart, Manolis Doxastakis, Vagelis Harmandaris
Summary: The study presents a bottom-up methodology to obtain coarse-grained models for copolymers through detailed atomistic simulations, using a dual-stage multi-component iterative Boltzmann inversion optimization scheme to derive effective CG interactions. The transferability of the PB copolymer model across molecular weight and copolymer composition is examined, with a focus on the impact of different isomers on conformational properties. The CG model is used to predict time mapping factors for segmental and center-of-mass dynamics of PB copolymers, showing potential applications in predicting polymer behavior.
Article
Astronomy & Astrophysics
A. Levi, A. Bansal, D. Sasselov
Summary: This study focuses on the speciation of carbon outgassing in ocean exoplanets. Filled ice containing CH4 in the ternary system H2O-CO2-CH4 has the potential to transport carbon into the atmosphere. This transportation is facilitated by a high-pressure, water-rich mantle and can explain the low atmospheric CO2 concentrations.
ASTROPHYSICAL JOURNAL
(2023)
Article
Engineering, Chemical
Wei Xiong, Lie-Hui Zhang, Yu-Long Zhao, Jian-Fa Wu, Jin-Hui Huang, Jian Yao
Summary: The study introduces an improved CPA-vdW model to predict the phase behavior of mixtures, with accurate predictions for different systems, which is helpful for simulating the process of CO2 injection to extract CH4.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Chemistry, Physical
Yafan Yang, Mohd Fuad Anwari Che Ruslan, Weiwei Zhu, Guangsi Zhao, Shuyu Sun
Summary: In this study, the interfacial behaviors in the H2O+CO2+C10H22 3-phase system and the effect of impurity gas CH4 on the interfacial properties were investigated using molecular dynamics simulation and density gradient theory. It was found that the interfacial tensions of all three interfaces increased when the system was in contact with CH4, with a more pronounced increment at low temperatures and high pressures. The research insights can enhance the understanding of the effects of impurities on CO2 enhanced oil recovery methods under geological conditions.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Energy & Fuels
Lu Zhang, Qibin Li, Chao Liu, Yang Liu, Shouyin Cai, Shukun Wang, Qinglin Cheng
Summary: Gas-water two-phase flow mechanism of CO2/CH4 in moist nanoporous media is studied in this research. Water molecules tend to form clusters to replace gas molecules at the surface and center region. An analytical theoretical slip model is established to quantify the effective viscosity and slip length of the binary mixtures system.
Article
Biochemical Research Methods
Damien Jefferies, Syma Khalid
Summary: Membrane proteins are amphipathic macromolecules with diverse chemical compositions and biological functions. Traditional experimental techniques and molecular modeling software, especially molecular dynamics algorithms, can provide comprehensive insights into the properties and dynamic behaviors of membrane proteins.
Article
Energy & Fuels
Wei Yong, Zhi-jie Wei, Yu-yang Liu, De-qiang Wang, Yong-zheng Cui
Summary: In this study, we used MD simulations to investigate the behavior of liquid droplets on a graphite substrate mimicking a carbon-rich pore surface in the presence of CH4/CO2 mixtures. Our results showed that the interfacial tension between water and methane, as well as between water and CH4/CO2 mixtures, agreed well with experimental and computational literature. We also found that the modified Young's equation successfully linked the macroscopic and microscopic contact angles, and that surface roughness enhanced the hydrophobicity of the solid surface.
FRONTIERS IN ENERGY RESEARCH
(2023)
Article
Astronomy & Astrophysics
P. Woitke, O. Herbort, Ch Helling, E. Stueken, M. Dominik, P. Barth, D. Samra
Summary: The study proposes a classification of exoplanet atmospheres based on the abundances of H, C, O, and N elements, identifying three types of atmospheres and suggesting the potential presence of graphite clouds in type C atmospheres. Models demonstrate that outgassing from warm rock can naturally create type C atmospheres.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Like Xu, Zhifeng Huang, Qiang Shen, Fei Chen
Summary: This study investigates the plasticity heterogeneity in different gradient nano-grained (GNG) metals through large-scale molecular dynamic simulations. The findings reveal metal-type dependence in terms of dislocation and deformation twinning-based plasticity. In terms of grain boundary activities, GNG Cu, Al, and Ni exhibit similar overall behavior, but GNG Ni shows higher grain boundary-free volume and stress due to the twinning process induced by grain size gradient.
MATERIALS & DESIGN
(2022)
Article
Chemistry, Physical
Kirill Shmilovich, Marc Stieffenhofer, Nicholas E. Charron, Moritz Hoffmann
Summary: Coarse-graining is a useful technique in molecular dynamics simulations to extend the time and length scales achievable in atomistic simulations. However, reconstructing the atomistic detail from coarse-grain structures is challenging due to the many possible atomistic configurations. Existing backmapping methods neglect information from previous trajectory frames, which is crucial for temporal coherence and high-fidelity reconstructions. This study presents a deep learning-driven approach that incorporates information from preceding trajectory structures to achieve temporally coherent backmapping.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Polymer Science
Christina A. Gatsiou, Andreas Bick, Xenophon Krokidis, Ioannis G. Economou
Summary: This research presents a generic methodology for deriving coarse-grained forcefields and a simulation strategy for obtaining relaxed structures of amorphous amylose. A specific coarse-grained forcefield for amylose was constructed and compared to the Martini forcefield, showing its superiority in predicting structural properties. This work has the potential for studying other bio-based polymers.
Article
Polymer Science
Alireza F. Behbahani, Ludwig Schneider, Anastassia Rissanou, Anthony Chazirakis, Petra Bacova, Pritam Kumar Jana, Wei Li, Manolis Doxastakis, Patrycja Polinska, Craig Burkhart, Marcus Mueller, Vagelis A. Harmandaris
Summary: A hierarchical simulation methodology is proposed for predicting the dynamical and rheological properties of entangled polymer melts, which includes atomistic, moderately coarse-grained (mCG), and highly coarse-grained slip-spring (SLSP) simulations. The methodology matches local structural distributions of the different levels and uses compensating pair potentials to keep static macromolecular properties unaltered.
Article
Chemistry, Physical
Fengyi Li, Weigang Ma, Xing Zhang
Summary: Hydrogen has attracted attention as a potential alternative to fossil fuel due to its renewable and environmentally friendly properties. Accurate estimations of the thermodynamic and thermophysical properties of hydrogen-containing mixtures are essential for efficiently designing hydrogen energy systems. This study introduced methods for calculating these properties and established a technical database covering a wide range of compositions, pressures, and temperatures. A user-friendly software called H2MixThermoDatabase was compiled to facilitate further developments in hydrogen energy systems.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
R. Villablanca-Ahues, R. Nagl, T. Zeiner, P. Jaeger
Summary: This study investigates and predicts the interfacial tension at elevated pressure for binary systems, which are crucial for the ongoing energy transition. A comprehensive review is conducted on saturated mixture densities and interfacial tension in binary, ternary, and quaternary systems containing nonpolar and polar compounds at elevated pressures. New experimental and theoretical data on binary systems are presented to fill the research gap, especially for quaternary model systems containing H2O, a hydrocarbon, a gas, and a surface-active compound. The experimental results are in good agreement with simulations and previously available data, showing an absolute average deviation ranging from 0.44 mN/m to 2.58 mN/m.
FLUID PHASE EQUILIBRIA
(2023)
Article
Thermodynamics
Wenfeng Guang, Zhenyu Zhang, Lei Zhang, P. G. Ranjith, Shengpeng Hao, Xiaoqian Liu
Summary: This study investigates the transport and diffusion behavior of CO2-CH4 mixture in coal nanopores using Monte Carlo and molecular dynamics simulation. A modified computational method for multi-component transport diffusivity is proposed. The results show that the confinement effect of nanopores significantly affects the diffusion behavior, and the pressure has different effects on the transport diffusivity. The CO2-CH4 mixture under greater confinement effect manifests higher diffusion selectivity, which benefits the separation and CH4 recovery.
Article
Thermodynamics
Simon Stephan, Harry Cardenas, Andres Mejia, Erich A. Mueller
Summary: This article revisits the description of density profiles at the vapor-liquid interface of mixtures in the seminal monograph 'Molecular Theory of Capillarity' by Rowlinson and Widom. It summarizes the different suggested morphologies at the interface and acknowledges the absence of reports on profiles with a single minimum. Both profiles with a single maximum and fully monotonic profiles have been extensively observed and reported. The presence of both a maximum and a minimum in the density profiles is controversial and has only been predicted using theoretical approaches like density gradient theory (DGT). This study investigates this ambiguity using the example of the vapor-liquid interface of cyclohexane + butanol, employing DGT and molecular dynamics simulations. The results from the two methods contradict each other, with DGT predicting a maximum/minimum structure while the computer experiment results show only a single maximum. Thus, this work highlights the need for caution when interpreting DGT results for highly non-ideal mixtures.
FLUID PHASE EQUILIBRIA
(2023)
Article
Chemistry, Physical
Brais Rodriguez-Garcia, Manuel M. Pineiro, Martin Perez-Rodriguez
Summary: In this study, we investigate the behavior of noble gases (He, Ne, Ar, and Kr) within a hydroquinone clathrate (HQC) using all-atom molecular dynamics simulations. Our results show that larger elements of the same group cannot fit inside the HQC cavities. By applying the umbrella sampling technique, we obtain the inter-cage transition barriers for these gases at 310 K and 0.1 MPa, which are crucial for determining their diffusion behavior: 1192, 2204, 6450, and 10 730 kJ mol(-1) for He, Ne, Ar, and Kr, respectively. These energy barriers exhibit a linear relationship with atomic radii (sigma), as demonstrated by the CH4 simulation.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Pablo Collado, Manuel M. M. Pineiro, Martin Perez-Rodriguez
Summary: In this study, the encapsulation of gaseous H2 and CO2 in a Type II porous liquid composed of nanometric scale cryptophane-111 molecules dispersed in dichloromethane was analyzed theoretically using atomistic molecular dynamics. The simulation showed that gaseous H2 initially occupied the cavities of cryptophane-111, while CO2 exhibited a significantly higher selectivity in adsorption. The calculations were performed at different temperature and pressure conditions, providing insights into the different adsorption behavior. The accessibility of the host molecule cavities was also evaluated based on the guest occupying the pores. The different intermolecular host-guest interactions were discussed to explain the varying selectivity observed in the molecular simulation calculations. The results demonstrate the potential feasibility of using nanometric scale porous liquids for renewable CO2 separation and storage.
Article
Physics, Multidisciplinary
Johan Gonzalez, Jose Matias Garrido, Hector Quinteros-Lama
Summary: This study compares two objective functions, the maximum efficiency function and the maximum net power output function, to achieve the optimal conditions in organic Rankine cycles. The results show that these objective functions and the maximum entropy point provide excellent references for describing the optimal conditions. These references enable finding the optimal operating conditions within a determined temperature range, named the optimal temperature range of the boiler in this study, for any working fluid.
Article
Chemistry, Physical
Jesus Algaba, Ivan M. Zeron, Jose Manuel Miguez, Joanna Grabowska, Samuel Blazquez, Eduardo Sanz, Carlos Vega, Felipe J. Blas
Summary: In this paper, the solubility of CO2 in water at 400 bar is determined using computer simulations. The solubility decreases in a liquid-liquid system with increasing temperature, while it increases in a hydrate-liquid system. The results are compared with previous work and a new method for evaluating the change in chemical potential for hydrate formation is proposed.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Cristobal Romero-Guzman, Ivan M. Zeron, Jesus Algaba, Bruno Mendiboure, Jose Manuel Miguez, Felipe J. Blas
Summary: In this study, the effect of pressure on the interfacial free energy of carbon dioxide hydrate-water is investigated using advanced computer simulation techniques. The simulation results show good agreement with experimental measurements in the literature. The results suggest a correlation between the interfacial free energy values and the pressure.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
J. Grabowska, S. Blazquez, E. Sanz, E. G. Noya, I. M. Zeron, J. Algaba, J. M. Miguez, F. J. Blas, C. Vega
Summary: In this study, the computer simulations were used to estimate the homogeneous nucleation rate of methane hydrate at 400 bars with a supercooling of about 35 K. The TIP4P/ICE model and a Lennard-Jones center were employed for water and methane, respectively. By using the seeding technique, clusters of different sizes of methane hydrate were introduced into a two-phase gas-liquid equilibrium system at 260 K and 400 bars. The nucleation rate was determined by considering several possibilities of order parameters and comparing with brute force simulations.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Jesus Algaba, Agustin Morales-Aragon, Cristobal Romero-Guzman, Paula Gomez-alvarez, Felipe J. Blas
Summary: In this study, the continuous Square-well potential was used to describe the equilibrium and interfacial properties of Square-well chains. The results show that with increasing chain length, the width of the coexistence phase increases, resulting in an increase in surface tension and critical temperature, while the vapor pressure and interfacial width decrease.
Article
Chemistry, Multidisciplinary
Brais Rodriguez Garcia, Manuel M. Pineiro, Martin Perez-Rodriguez
Summary: Umbrella Sampling Molecular Dynamics method was used to study the transition energies and temperature trend of different guest molecules in hydroquinone beta-clathrate nanochannels. The clathrate can selectively encapsulate various types of small gases, making it a potential candidate for gas separation and storage. Most guest gases can be accurately modeled as single Lennard-Jones spheres.
Article
Thermodynamics
Johan Gonzalez, Felix Llovell, Jose Matias Garrido, Hector Quinteros-Lama
Summary: This study analyzed a vapor compression refrigeration cycle (VCRC) driven by an organic Rankine cycle (ORC) and found that the combination of n-pentane and R1233zd provided good performance compared to other refrigerants.
FLUID PHASE EQUILIBRIA
(2023)
Article
Engineering, Chemical
Ilya Polishuk, Esteban Cea-Klapp, Jose Matias Garrido, Dong NguyenHuynh
Summary: This study compares the capabilities of CP-PC-SAFT and CS-SAFT-VR-Mie models in predicting VLE, LLE, and critical data of 74 binary systems. The results show that both models provide accurate estimations of vapor pressures and pure compound saturated liquid densities. However, CP-PC-SAFT performs better in predicting high-pressure density and sound velocity, while CS-SAFT-VR-Mie exhibits unrealistic transitional behavior and inaccurate predictions of LLE.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Engineering, Chemical
Franco Espinoza-Cartagena, Sebastiain Ormazabal-Latorre, Ceisar Pazo-Carballo, Nicolais F. Gajardo-Parra, Gonzalo A. Nunnez, Jose Matias Garrido, Esteban Cea-Klapp, Rubein Santiago, Christoph Held, Roberto I. Canales
Summary: Thebiorefinery concept is a potential source of products for the fuel industry, particularly biojet fuel, but the presence of highly oxygenated species makes it unsuitable as a final product. This study focuses on solvent extraction of phenolic compounds from biojet fuel to upgrade its matrix, using isoeugenol as a model phenolic molecule and methylcyclohexane as a representative solvent. The results show that diethylene glycol is the best alternative for extracting isoeugenol.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Joaquin Otarola-Sepulveda, Esteban Cea-Klapp, Paulo Aravena, Sebastian Ormazabal-Latorre, Roberto I. Canales, Jose Matias Garrido, Oscar Valerio
Summary: This study compares the solubility predictions of Flory-Huggins based on the Hansen Solubility Parameters (FH-HSP) model with openCOSMO-RS and PC-SAFT, finding good performance in predicting the solubility of thymol and L-menthol but significant deviations for solid solutes in cyclohexanone. For DES solubility predictions compared to experimental data, RMSLD values of FH-HSP, openCOSMO-RS, and PC-SAFT were 0.86, 0.27, and 0.93 respectively. The results suggest that the HSP theory can aid DES screening processes by identifying promising DES-solute pairs.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Thermodynamics
Johan Gonzalez, Felix Llovell, Jose Matias Garrido, Hector Quinteros-Lama
Summary: VCR-ORC systems combine ORC and VCRC to generate energy from low-moderate temperature sources. This study focuses on the development of accurate objective functions for optimal system performance and the selection of working fluids, finding that pentane and R1233zd are the best choices.