Instability Deposit Patterns in an Evaporating Droplet

The characteristics of several patterns left after the evaporation of a particle-laden liquid droplet are investigated by using a coarse-grained lattice model. The model includes both evaporative convection and the Brownian motion of weakly interacting particles. The model is implemented by using a Monte Carlo method to investigate the different deposit patterns near the contact line. It was found that different deposit patterns form depending on the interplay between the convective transport and the deposition of interacting particles. The patterns were analyzed by varying the ratio of the convective forces to the interaction forces as well as the size and the number of particles. It was also found that the ring-like patterns are formed when the convective potential dominates the interactions of particles, whereas either wave-like or island-like patterns form in the opposite case. Finally, the average thickness of the wave-like patterns is mainly determined by evaporation rates.close0

Constant pressure path integral Gibbs ensemble Monte Carlo method

We present the implementation of a real-space constant pressure path integral Gibbs ensemble Monte Carlo (CP-PIGEMC) method for the simulation of one-component fluid consists of distinguishable quantum particles (henceforth referred to as Boltzmannons) in an external potential field at finite temperatures. We apply this simulation method to study the para-H2 adsorption in NaX zeolite at 77 K and pressures up to 100 bar. We present a new set of effective solid-fluid parameters optimized for path integral simulations of hydrogen isotope adsorption and separation in synthetic zeolites. The agreement among CP-PIGEMC, experiment, and the path integral grand canonical Monte Carlo method (PIGCMC) is very good, even at high pressures. CP-PIGEMC is a particularly useful method for simulation of one-component quantum fluid composed of Boltzmannons at finite temperatures, when the chemical potential is difficult to measure or calculate explicitly.We present the implementation of a real-space constant pressure path integral Gibbs ensemble Monte Carlo (CP-PIGEMC) method for the simulation of one-component fluid consists of distinguishable quantum particles (henceforth referred to as Boltzmannons) in an external potential field at finite temperatures. We apply this simulation method to study the para-H2 adsorption in NaX zeolite at 77 K and pressures up to 100 bar. We present a new set of effective solid-fluid parameters optimized for path integral simulations of hydrogen isotope adsorption and separation in synthetic zeolites. The agreement among CP-PIGEMC, experiment, and the path integral grand canonical Monte Carlo method (PIGCMC) is very good, even at high pressures. CP-PIGEMC is a particularly useful method for simulation of one-component quantum fluid composed of Boltzmannons at finite temperatures, when the chemical potential is difficult to measure or calculate explicitly

Cryogenic Noble Gas Separation without Distillation: The Effect of Carbon Surface Curvature on Adsorptive Separation

Applying a novel self-consistent Feynman−Kleinert−Sesé variational approach (Sesé, L. M. Mol. Phys.1999, 97, 881−896) to quantum thermodynamics and the ideal adsorbed solution theory, we studied adsorption and equilibrium separation of 20Ne−4He mixtures in carbonaceous nanomaterials consisting of flat (graphite-like lamellar nanostructures) and curved (triply periodic minimal carbon surfaces) nanopores at 77 K. At the infinite mixture dilution, Schwarz P-carbon and Schoen G-carbon sample represents potentially efficient adsorbents for equilibrium separation of 20Ne−4He mixtures. The equilibrium selectivity of 20Ne over 4He (αNe−He) computed for Schwarz P-carbon and Schoen G-carbon sample is very high and reaches 219 and 163 at low pore loadings, respectively. Graphite-like lamellar nanostructures with interlamellar spacing (Δ) less than 0.6 nm are also potential adsorbents for equilibrium separation of 20Ne−4He mixtures at cryogenic temperatures. Here, αNe−He of 80 is predicted for Δ = 0.46 nm at low pore loadings. The quantum-corrected molar enthalpy of 20Ne adsorption strongly depends on the curvature of carbon nanopores.For Schwarz P-carbon sample, it reaches 8.2 kJ mol−1, whereas for graphite-like lamellar nanostructures the maximum enthalpy of 20Ne physisorption of 5.6 kJ mol−1 is predicted at low pore loadings. In great contrast, the quantum-corrected molar enthalpy of 4He adsorption is only slightly affected by the curvature of carbon nanopores. The maximum heat released during the 4He physisorption is 3.1 (Schwarz P-carbon) and 2.7 kJ mol−1 (graphite-like lamellar nanostructure consisting of the smallest flat carbon nanopores). Interestingly, for all studied carbonaceous nanomaterials consisting of curved/flat nanopores, αNe−He computed for the equimolar composition of 20Ne−4He gaseous phases is still very high at total mixture pressure up to 1 kPa. This circumstance is indicative of the possibility of carrying out the adsorption separation of 20Ne−4He mixtures at pt < 1 kPa and 77 K that do not require high-energy consumption. Presented potential models and simulation methods will further enhance the accuracy of modeling of confined inhomogeneous quantum fluids at finite temperatures