A5014826801- Thermal properties of materials
- Advanced Thermoelectric Materials and Devices
- Thermal Radiation and Cooling Technologies
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Thermal Expansion and Ionic Conductivity
- Machine Learning in Materials Science
- Carbon Nanotubes in Composites
- Nanopore and Nanochannel Transport Studies
- Semiconductor materials and devices
- nanoparticles nucleation surface interactions
- Graphene research and applications
- Phase Equilibria and Thermodynamics
- Ferroelectric and Piezoelectric Materials
- Metal-Organic Frameworks: Synthesis and Applications
- Advanced Thermodynamics and Statistical Mechanics
- Molecular Junctions and Nanostructures
- Advancements in Semiconductor Devices and Circuit Design
- Electronic and Structural Properties of Oxides
- Thermography and Photoacoustic Techniques
- High-pressure geophysics and materials
- Dielectric materials and actuators
- Catalytic Processes in Materials Science
- Crystallography and molecular interactions
- Advanced Sensor and Energy Harvesting Materials
Carnegie Mellon University
2016-2025
University of Michigan
2002-2020
University of Florida
2005-2011
Rensselaer Polytechnic Institute
2009
University of Pittsburgh
2005
University of Toronto
2000-2003
Pressure-driven water flow through carbon nanotubes (CNTs) with diameters ranging from 1.66 to 4.99 nm is examined using molecular dynamics simulation. The rate enhancement, defined as the ratio of observed that predicted no-slip Hagen-Poiseuille relation, calculated for each CNT. enhancement decreases increasing CNT diameter and ranges 433 47. By calculating variation viscosity slip length a function diameter, it found results can be fully explained in context continuum fluid mechanics....
Abstract Using first principles calculations, we predict the thermal conductivity of two-dimensional materials black phosphorene and blue phosphorene. Black has an unprecedented anisotropy ratio three, with predicted values 110 W/m-K 36 along its armchair zigzag directions at a temperature 300 K. For phosphorene, which is isotropic structure, value 78 W/m-K. The two allotropes show strikingly different accumulation, phonons mean free paths between 10 nm 1 μm dominating in while much narrower...
The structure and flow of water inside 75 150 nm-long carbon nanotubes with diameters ranging from 0.83 to 1.66 nm are examined using molecular dynamics simulation. rate enhancement, defined as the ratio observed that predicted no-slip Poiseuille relation, is calculated for each tube liquid an axial distribution function. relationship between intermolecular quantified differences continuum subcontinuum discussed.
We predict the bulk thermal conductivity of Lennard-Jones argon and Stillinger-Weber silicon using Green-Kubo (GK) direct methods in classical molecular dynamics simulations. While system-size-independent conductivities can be obtained with less than 1000 atoms for both materials GK method, linear extrapolation procedure [Schelling et al., Phys. Rev. B 65, 144306 (2002)] must applied to method results multiple system sizes. find that applying a manner consistent previous researchers lead an...
We derive and validate a technique for predicting phonon dispersion relations lifetimes from the atomic velocities in crystal using spectral energy density. This procedure, applied here to carbon nanotubes, incorporates full anharmonicity of interactions into lifetime frequency predictions. It can also account nonperiodic between phonons nonbonded molecules near solid surface. properties obtained anharmonic lattice dynamics calculations thermal conductivities nonequilibrium...
Two methods for predicting phonon frequencies and relaxation times are presented. The first is based on quasiharmonic anharmonic lattice dynamics calculations, the second a combination of calculations molecular simulations. These properties then used with Boltzmann transport equation under relaxation-time approximation to predict thermal conductivity. validity low-temperature assumptions made in framework assessed by comparing conductivities predicted Green-Kubo direct test system...
The accuracies of two theoretical expressions for thermal boundary resistance are assessed by comparing their predictions to independent from molecular dynamics (MD) simulations. In one expression $({R}_{E})$, the phonon distributions assumed follow equilibrium, Bose-Einstein distribution, while in other $({R}_{NE})$, phonons have nonequilibrium, but bulk-like distributions. properties obtained using lattice dynamics-based methods, which assume that interface scattering is specular and...
We predict the properties of propagating and nonpropagating vibrational modes in amorphous silica ($a$-SiO${}_{2}$) silicon ($a$-Si) and, from them, thermal conductivity accumulation functions. The calculations are performed using molecular dynamics simulations, lattice calculations, theoretical models. For $a$-SiO${}_{2}$, contribute negligibly to (6$%$), agreement with measured by Regner et al. [Nat. Commun. 4, 1640 (2013)]. $a$-Si, mean-free paths up 1 $\ensuremath{\mu}$m 40$%$ total...
Mode-dependent phonon and electron transport properties in Al, Ag, Au are predicted using density functional theory lattice dynamics calculations. The thermal conductivities, electrical electron-phonon coupling coefficients, mass enhancement parameters agreement with experimental measurements. At a temperature of 100 K, the contribution to total conductivity Al is 5% bulk increases 15% for 50 nm thick film. In all three metals, phonons mean free paths between 1 10 dominate contributors at...
A computational framework for predicting phonon frequencies, group velocities, scattering rates, and the resulting lattice thermal conductivity is described. The underlying theory implementation suggestions are also provided. By using input from first principles calculations taking advantage of advances in power, this has enabled predictions that agree with experimental measurements diverse crystalline materials over a wide range temperatures. Density functional density perturbation used to...
Abstract Thermal energy management in metal-organic frameworks (MOFs) is an important, yet often neglected, challenge for many adsorption-based applications such as gas storage and separations. Despite its importance, there insufficient understanding of the structure-property relationships governing thermal transport MOFs. To provide a data-driven perspective into these relationships, here we perform large-scale computational screening conductivity k MOFs, leveraging classical molecular...
The phonon thermal conductivity of the Lennard-Jones argon face-centered cubic crystal is predicted between temperatures 20 K and 80 using Boltzmann transport equation under single-mode relaxation time approximation. temperature frequency dependencies dispersion times are obtained from lattice-dynamics calculations based on results molecular-dynamics simulations. No fitting parameters required. conductivities in reasonable agreement with independent predictions made simulations Green-Kubo...
The validity of the commonly used quantum corrections for mapping a classically predicted thermal conductivity onto corresponding value are assessed by self-consistently predicting classical and conductivities crystalline silicon system via lattice-dynamics calculations. Applying to predictions, with or without zero-point energy, does not bring them into better agreement predictions compared uncorrected values above temperatures 200 K. By examining mode dependence phonon properties, we...
The thermal conductivities of empty and water-filled single-walled carbon nanotubes (CNTs) with diameters between 0.83 1.36 nm lengths ranging from 200 to 1400 are predicted using molecular dynamics simulation. Using a direct application the Fourier law, we explore transition fully diffusive phonon transport increasing CNT length. For CNTs, find that length required obtain decreases 1090 for 0.83-nm-diameter 510 1.36-nm-diameter CNT. magnitude conductivity also monotonically diameter. We...
The suitability of the Green--Kubo method for predicting thermal conductivity nanocomposites is assessed by studying model Lennard-Jones superlattices. Good agreement found when comparing predicted cross-plane conductivities to independent predictions from direct method. link between superlattice unit cell design and tensor then explored. We find that complex, multilayered designs can reduce 17% compared minimum value superlattices with only two layers in cell. These results suggest new...
We investigate the effect of pore size and shape on thermal conductivity a series idealized metal-organic frameworks (MOFs) containing adsorbed gas using molecular simulations.