The thermal conductivity of single-walled and multi-walled carbon nanotubes has been investigated as a function the tube length L, temperature chiral index using non-equilibrium molecular dynamics simulations. In ballistic–diffusive regime follows Lα law. exponent α is insensitive to diameter nanotube; α≈0.77 derived for short at room temperature. dependence shows peak before falling higher temperatures (>500 K). phenomenon rectification in by gradually changing atomic mass tube-axial...

Innovation in plastic waste recycling technologies is essential for tackling the environmental challenges of pollution. Traditional management strategies, such as landfill disposal and mechanical recycling, are increasingly recognized insufficient addressing problem’s complexity scale. This review highlights advanced methods that transform into valuable resources, aligning with circular economy principles. I focus on cutting-edge chemical convert mixed contaminated plastics back monomers new...

A thorough understanding of the kinetics and dynamics combusting mixtures is considerable interest, especially in regimes beyond reach current experimental validation. The ReaxFF reactive force field method has provided a way to simulate large-scale systems hydrogen combustion via parametrized potential that can bond breaking. This modeling approach been applied combustion, as well myriad other chemical systems. In this work, we benchmark performance several common parametrizations against...

The thermal conductivity in a set of mass-graded nanosized model systems has been studied by nonequilibrium molecular dynamics (MD) simulations order to understand the phenomenon rectification that detected externally mass-loaded nanotubes. We have found preferred direction heat transport nanotubes occurs from light heavy atoms while opposite transfer is observed anharmonic single-file chains. Mass-graded polyacetylenelike chains behave like as long mass gradient held backbone atoms. with...

Abstract Using molecular dynamics simulations with an OPLS force field, the lower critical solution temperature (LCST) of single‐ and multiple‐chain PNIPAM solutions in water is investigated. The sample containing ten polymer chains shows a sudden drop size volume at 305 K. Such effect absent single‐chain system. Large fluctuations physical properties short prevent any clear detection LCST for chosen model system, least on time scale 200 ns. results provide evidence that number monomer units...

Understanding heat transfer in composite materials is essential for optimizing their performance critical applications across industries such as aerospace, automotive, renewable energy, and construction. This review offers a comprehensive examination of the various mechanisms within explores how these processes, spanning different length time scales, are influenced by materials' composition structure. Both traditional advanced analytical numerical modeling techniques explored, emphasizing...

Understanding heat transfer in composite materials is essential for optimizing their performance critical applications across industries such as aerospace, automotive, renewable energy, and construction. This review offers a comprehensive examination of the various mechanisms within explores how these processes, spanning different length time scales, are influenced by materials’ composition structure. Both traditional advanced analytical numerical modeling techniques explored, emphasizing...

The thermal rectification in nanotubes with a mass gradient is studied by reverse non-equilibrium molecular dynamics simulations. We predict preferred heat flow from light to heavy atoms which differs the preferential direction one-dimensional monoatomic systems. This behavior of explained anharmonicities caused transverse motions are stronger at low-mass end. present simulations show an enhanced increasing tube length, diameter and gradient. Implications findings for applied topics...

The thermal conductivity of composites carbon nanotubes and polyamide-6,6 has been investigated using reverse non-equilibrium molecular dynamics simulations in a full atomistic resolution. It is found, line with experiments, that the have conductivities, which are only moderately larger than pure polyamide. composite conductivities orders magnitude less what would be expected from naïve additivity arguments. This means intrinsic isolated nanotubes, exceed best-conducting metals, cannot...

The synthesis of a stereochemically pure concave tribenzotriquinacene receptor (7) for C60 fullerene, possessing C3 point group symmetry, by threefold condensation C2 -symmetric 1,2-diketone synthons (5) and hexaaminotribenzotriquinacene core (6) is described. chiral diketone was synthesized in five-step reaction sequence starting from C2h 2,6-di-tert-butylanthracene. highly diastereo-discriminating Diels-Alder 2,6-di-tert-butylanthracene with fumaric acid di(-)menthyl ester, catalyzed...

The thermal conductivity (λ) of nanoconfined polyamide-6,6 (PA) oligomers in polymer–graphene nanocomposites has been investigated by reverse nonequilibrium molecular dynamics (RNEMD) simulations. preferential alignment the PA chains parallel to graphene plane as well their elongation implies that λ polymer is larger than neat system. ordering phase enhanced an arrangement charged surfaces made one layer with a charge deficit and excess. consequence denser packing increase network....

The thermal conductivity (λ) of stretched amorphous atactic polystyrene (PS) swollen in supercritical carbon dioxide (sc CO2) has been investigated over a wide temperature, pressure, and concentration range. Nonequilibrium molecular dynamics simulations with full atomistic force-field have employed to calculate the neat PS different mixtures CO2 PS. As energy transport parallel perpendicular stretching direction differs, an anisotropy occurs. magnitude λ is enhanced increasing number...

Abstract We report the synthesis of a tribenzotriquinacene‐based (TBTQ) receptor ( 3 ) for C 60 fullerene, which is extended by pentiptycene moieties to provide an almost enclosed concave ball bearing. The system serves as model self‐assembling molecular rotor with flexible and adapting stator. Unexpectedly, nuclear magnetic resonance spectroscopic investigations reveal surprisingly low complex stability constant K 1 =213±37 M −1 [C ⊂ ], seemingly inconsistent previously reported TBTQ...

We employ reverse nonequilibrium molecular dynamics simulations to investigate the interfacial heat transfer in composites formed by an ungrafted or a grafted carbon nanotube which is surrounded oligomeric polyamide-6,6 chains. The structural properties of polymer matrix and chains are also studied. influence grafting density, length as well their chemical composition on thermal conductivity (λi) focus our computational study. For considered polyethylene polyamide we do not find sizeable...

The thermal conductivity of amorphous atactic polystyrene (PS) swollen in supercritical carbon dioxide (sc CO(2)) has been investigated over wide temperature, pressure, and concentration ranges. Nonequilibrium molecular dynamics simulations with a full atomistic force field have used to calculate the neat PS sc CO(2) as well binary system at different compositions. An analytical interpolation formula for mixture on basis data obtained. Particular attention paid implications quasi-degeneracy...

The temperature-responsive behavior of functionalized metal–organic frameworks (fu-MOF) with the general formula [Zn2(fu-L)2dabco]n has been investigated using molecular dynamics simulations (fu-L = alkoxy-functionalized 1,4-benzenedicarboxylate, dabco 1,4-diazabicyclo[2.2.2]octane). studied show a narrow pore (np) form at low temperatures, while higher large (lp) structures can be observed. transition temperature is controlled by chemical nature linker's side chains as well their length. In...

When at equilibrium, large-scale systems obey thermodynamics because they have microscopic configurations that are typical. "Typical" states a fraction of those possible with the majority probability. A more precise definition typical underlies transmission, coding, and compression information. However, this does not apply to natural transiently away from equilibrium. Here, we introduce variational measure typicality it atomistic simulations model for hydrogen oxidation. While gaseous...

Structure and dynamic behavior of the thermo-responsive polymer poly(N-isopropylacrylamide) (PNIPAM) endgrafted onto inner surface a simple cylindrical pore model that resembles carbon nanotube (CNT) with diameter 8.4 nm is studied as function temperature, surface-polymer interaction strength, water content. A free PNIPAM chain in shows lower critical solution temperature (LCST) about 305 K. We have investigated two different strengths PNIPAM-pore interactions. In strong case, which...

Transient, macroscopic states of chemical disequilibrium are born out the microscopic dynamics molecules. As a reaction mixture evolves, temporal patterns species encodes some this dynamical information, while their statistics manifestation bulk kinetics. Here, we define chemically-informed symbolic as coarse-grained representation classical molecular dynamics, and analyze sequences for model hydrogen combustion. We use reactive simulations to generate derive probability distributions...

Abstract The thermal conductivity (λ) of carbon nanotubes (CNTs) with chirality indices (5,0), (10,0), (5,5), and (10,10) has been studied by reverse nonequilibrium molecular dynamics (RNEMD) simulations as a function different bond length alternation patterns (Δ r i ). Δ dependence the force constant ( k rx ) in field modeled help an electronic band structure approach. These calculations show that tubes not too small diameter can be mapped simple linear length–bond order correlation. A...

While hydrogen is a promising source of clean energy, the safety and optimization technologies rely on controlling ignition through explosion limits: pressure-temperature boundaries separating explosive behavior from comparatively slow burning. Here, we show that emergent nonequilibrium chemistry combustible mixtures can exhibit quantitative features phase transition. With stochastic simulations chemical kinetics for model mechanism combustion, marking domains kinetic are critical points....

Using reverse nonequilibrium molecular dynamics simulations the influence of intermolecular bridges on thermal conductivity (λ) in carbon nanotube (CNT) bundles has been investigated. The chosen cross linkers (CH2, O, CO) strengthen transversal energy transport relative to one CNT without bridges. results showed that λ does not increase linearly with linker density. efficiency heat is determined by number direction flux, type linker, and their spatial ordering. a forced axial stress also...

Hydrogen is a potential substitute for fossil fuels that would reduce the combustive emission of carbon dioxide. However, low ignition energy needed to initiate oxidation imposes constraints on efficiency and safety hydrogen-based technologies. Microscopic details combustion processes, ephemeral transient species, complex reaction networks are necessary control optimize use hydrogen as commercial fuel. Here, we report estimates time hydrogen-oxygen mixtures over wide range equivalence ratios...