Non-equilibrium molecular dynamic (NEMD) simulations have been used to study heat and mass transfer across a vapor-liquid interface for a one-component system using a Lennard-Jones spline potential. It was confirmed that the relation between the surface tension and the surface temperature in the non-equilibrium system was the same as in equilibrium (local equilibrium). Interfacial transfer coef...

An instrument for measuring the creep response of a material maintained under a controlled environment of temperature and vapor pressure is described. The temperature range of the instrument is 20-250 degrees C while the range of vapor pressure is 0-1 atm. Data are presented for tests conducted on this instrument with Nafion, a perfluorinated ionomer developed by DuPont and used as a membrane i...

Pollen from deep-sea sedimentary sequences provides an integrated regional reconstruction of vegetation and climate (temperature, precipitation, and seasonality) on the adjacent continent. More importantly, the direct correlation of pollen, marine and ice indicators allows comparison of the atmospheric climatic changes that have affected the continent with the response of the Earth's other rese...

Predictive modeling of reaction equilibria presents one of the grand challenges in the field of molecular simulation. Difficulties in the study of such systems arise from the need (i) to accurately model both strong, short-ranged interactions leading to the formation of chemical bonds and weak interactions arising from the environment, and (ii) to sample the range of time scales involving frequ...

In a previous paper [I. Napari, J. Julin, and H. Vehkamäki, J. Chem. Phys. 131, 244511 (2009)] we compared sizes of critical and equilibrium clusters in Lennard-Jones vapors using various geometrical clusters definitions. In particular, we found that the critical and equilibrium clusters were of the same size if each constituent atom in the cluster was required to have at least five neighboring...

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concave...

Improved methods are needed to study sorption of vapor molecules by particles in the gas phase (heterogeneous uptake), which is an important process in both natural and engineered environments. Here, a new measurement system, composed of a differential mobility analyzer (DMA) and drift tube ion mobility spectrometer (DTIMS) in series, is used to examine the heterogeneous uptake of water vapor b...

[1] Convective turbulence within the atmospheric boundary layer (ABL) and movement of the ABL over the surface results in a large spatial (10–10 km) integration of surface fluxes that affects the CO2 and water vapor mixing ratios. We apply quasi-equilibrium concepts for the terrestrial ABL to measurements of CO2 and water vapor made within the ABL from a tall tower (396 m) in Wisconsin. We supp...