The pressure tensor (equivalent to the negative stress tensor) at both microscopic and macroscopic levels is fundamental many aspects of engineering science, including fluid dynamics, solid mechanics, biophysics, thermodynamics. In this Perspective, we review methods calculate tensor. Connections between different forms for equilibrium nonequilibrium systems are established. We also point out several challenges in field, historical controversies over definition tensor; difficulties with...

Using calculations from first principles, we found that water can dissociate over defective sites in graphene or nanotubes following many possible reaction pathways, some of which have activation barriers lower than half the value for dissociation bulk water. This reduction is caused by spin selection rules allow system to remain on same surface throughout reaction.

Crystallization is fundamental to many aspects of physics and chemistry in addition being technological relevance, for example, the chemical, food, pharmaceutical industries. However, design crystalline materials crystallization processes often challenging due variables that can influence process. As a part an effort gain molecular-level understanding way molecules aggregate organize themselves into crystal structures, this work we present new method construct order parameters suitable study...

A methodology for the determination of solid-fluid contact angle, to be employed within molecular dynamics (MD) simulations, is developed and systematically applied. The calculation angle a fluid drop on given surface, averaged over an equilibrated MD trajectory, divided in three main steps: (i) molecules that constitute interface, (ii) treatment interfacial as point cloud data set define geometric using surface meshing techniques compute normals from mesh, (iii) collection averaging...

Enhanced oil recovery (EOR) via carbon dioxide (CO2) flooding has received a considerable amount of attention as an economically feasible method for sequestration, with many recent studies focusing on developing enhanced CO2 foaming additives. However, the potential long-term environmental effects these additives in event leakage are poorly understood and, given injected typical EOR operation, could be far-reaching. This paper presents summary developments surfactant and...

Metals tend to supercool-that is, they freeze at temperatures below their melting points. In general, supercooling is less favorable when liquids are in contact with nucleation sites such as rough surfaces. Interestingly, bulk gallium (Ga) can significantly supercool, even it heterogeneous surfaces that could provide sites. We hypothesized the native oxide on Ga provides an atomically smooth interface prevents from directly contacting surfaces, and thereby promotes supercooling. Although...

Polymer-coated metals are ubiquitous in multiple industries as a corrosion protection strategy. Particularly food and beverage packaging, bisphenol A (BPA)-based epoxy coatings provide an excellent barrier strong adhesion to metals. There is, however, need design safer, alternative with similar BPA-epoxies due environmental health concerns associated BPA. Limited critical information exists on epoxy-metal interactions the effect of interfacial functional group concentration overall...

High oxygen carrying capacity, lack of loosely bound lattice oxygen, and preferential surface segregation Ba make BaMn_xB_1−xO₃ (B = Ni or Fe) based redox catalysts suitable for chemical looping reforming methane with high syngas yield coke resistance.

The application of the Young–Laplace equation to a solid–liquid interface is considered. Computer simulations show that pressure inside solid cluster hard spheres smaller than external liquid (both for small and large clusters). This would suggest negative value interfacial free energy. We in Gibbsian description thermodynamics curved equilibrium, choice thermodynamic (rather mechanical) required, as suggested by Tolman liquid–gas scenario. With this definition, energy positive, values...

Chemical looping with oxygen uncoupling (CLOU) is a novel process for carbon dioxide capture from coal combustion. Designing metal oxide carrier suitable release and uptake (redox) properties represents one of the most critical aspects CLOU. The current work aims to correlate vacancy creation energy carriers their redox properties. Oxygen energies CaMnO3−δ, Ca0.75Sr0.25MnO3−δ, CaMn0.75Fe0.25O3−δ, BaMnO3−δ were determined through density functional theory (DFT) calculations. effect Hubbard U...

The packing of binary and polydisperse unimodal bimodal ensembles hard spheres in the limit high pressure is studied using a sequential addition algorithm. Upon fixing number particles, their size distribution, average (maximum) fraction determined for systems up to 20 000 particles. structures obtained correspond amorphous states close dense random density. Binary distributions are denser than equivalent monodisperse distribution agree with theoretical prediction an infinite ratio limit....

Abstract HPLC columns custom‐packed with metal–organic framework (MOF) materials are used for the separation of four small intermediates and byproducts found in commercial synthesis an important active pharmaceutical ingredient methanol. In particular, two closely related amines can be separated methanol reaction medium using MOFs, but not traditional C18 optimized aqueous mobile phase. Infrared spectroscopy, UV–vis X‐ray diffraction, thermogravimetric analysis combination molecular dynamic...

Abstract We present a review of the most widely used methods to model chemical reactions, at both electronic and atomistic levels. While, in principle, ab initio alone should provide required prediction reaction mechanisms, yields rates, practice this can rarely be achieved due intensive nature computations poor scaling computational burden with number electrons. In many applications combination semi-classical simulations will needed. Specialized simulation are necessary, since reactions...

Nucleation is the key step in crystallization by which molecules (or atoms or ions) aggregate together, find right relative orientations, and start to grow form final crystal structure. Since nucleation an activated involving a large gap time scales between molecular motions event itself, must be studied using rare events methods. We employ technique developed previously our group known as aimless shooting [Peters, B.; Trout, B. L. J. Chem. Phys., 2006, 125, 054108], based on transition path...

Experimental studies have shown the formation of soluble complexes in pure repulsive Coulombic regime even when net charges protein and polyelectrolyte same sign (De Kruif et al. Curr. Opin. Colloid Interface Sci. 2004, 9, 340; De Vries J. Chem. Phys. 2003, 118, 4649; Grymonpre Biomacromolecules 2001, 2, 422; Hattori Langmuir 2000, 16, 9738). This attractive phenomenon has often been described as "complexation on wrong side pI". While one theory assumes existence "charged patches" surface...

Recently, several experimental and simulation studies have found that phenomena normally occur at extremely high pressures in a bulk phase can nanophases confined within porous materials much lower pressures, thus providing an alternative route to study high-pressure phenomena. In this work, we examine the effect on tangential pressure of varying molecular shape, strength fluid–wall interactions, pore width, for carbon slit-shaped pores. We find that, multisite molecules, presence additional...

Peptoids, or poly‐n‐substituted glycines, are peptide‐like polymers composed of a flexible backbone decorated with diverse chemical side chains. Peptoids can form variety self‐assembling structures based on the type and sequence chains attached to their backbones. All‐atom molecular dynamics simulations have been useful in predicting conformational proteins will be valuable tools for identifying combinations peptoid that may interesting folded structures. However, models must address major...

We present a reconfigurable flow chemistry strategy for facile transition between accelerated screening and continuous synthesis of linear aldehydes through homogeneous rhodium-catalyzed hydroformylation alkenes. The intensified mass heat transport rates the utilized membrane-based reactor enable access to safe desirable reaction conditions (i.e., 50 psig syngas pressure) while providing high chemoselectivity regioselectivity produced aldehydes. Additionally, by conducting hydrogen–deuterium...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Francisco R. Hung, Benoit Coasne, Erik E. Santiso, Keith Gubbins, Flor Siperstein, Malgorzata Sliwinska-Bartkowiak; Molecular modeling of freezing simple fluids confined within carbon nanotubes. J. Chem. Phys. 8 April 2005; 122 (14): 144706. https://doi.org/10.1063/1.1881072 Download citation file: Ris (Zotero)...

The scheduled delivery of synergistic drug combinations is increasingly recognized as highly effective against advanced solid tumors. Of particular interest are composite systems that release a sequence drugs with defined kinetics and molar ratios to enhance therapeutic effect, while minimizing the dose patients. In this work, we developed homogeneous comprising modified graphene oxide (GO) nanoparticles embedded in Max8 peptide hydrogel, which provides controlled doxorubicin (DOX)...