Recent measurements of the temperature profile across interface an evaporating liquid are in strong disagreement with predictions from classical kinetic theory or nonequilibrium thermodynamics. However, these previous vapor were made within a minimum 27 mean free paths interface. Since indicates that sharp changes can occur near liquid, series experiments performed to determine if could be resolved by closer The reported herein as close one path liquid. results indicate it is higher-energy...

Recent measurements of the conditions existing at interface an evaporating liquid have found that temperature approximately one mean free path from in vapor was higher than interface. The measured discontinuity is opposite direction predicted by several recent studies based on classical kinetic theory. A theoretical approach transition probability concept quantum mechanics, called statistical rate theory (SRT), used herein to develop expression for predicting evaporation flux. obtained any...

After assuming that the transport of molecules between phases at thermal equilibrium results primarily from single molecular events, expression for rate is developed by using a first order perturbation analysis Schrödinger equation and Boltzmann definition entropy. This leads to an Einstein-type relation with constant proportionality being average exchange microscopic states different distributions. A hypothesis introduced which conclusion this unchanged as system moves through distributions...

Gas-vapor nucleation in liquid solutions is considered. It shown that for to occur a multicomponent solution nucleus must be created of at least certain radius. Consideration then restricted weak gas dissolved liquids with the allowed behave nonideally. A generalized Kelvin equation derived which relates partial pressure solvent vapor inside properties surrounding solution. how, given temperature, occurs gas-liquid increased as concentration increased.

Steady-state evaporation and condensation experiments have been conducted with water under conditions where buoyancy-driven convection is not present. The temperature profile in each phase has measured. At the interface, independently of direction change, a discontinuity found to exist which interfacial vapor greater than that liquid. In thin layer immediately below interface uniform ( approximately 0.5 mm) linear, indicating thermal conduction. indicates mixing process occurs near could...

Water has been examined for thermocapillary convection while maintained just outside the mouth of a stainless-steel, conical funnel where it evaporated at different but steady rates. Evaporation series controlled rates was produced by reducing pressure in vapor-phase to constant values maintaining temperature water few millimeters below interface 3.56+/-0.03 degrees C each case. Since its maximum density 4 C, these conditions ensured there would be no buoyancy-driven convection. The measured...

To determine the diffusion coefficient of a gas in liquid usual procedure is to expose interface for period time, measure amount absorption, and from this infer coefficient. The assumption make at liquid–gas that equilibrium established immediately upon exposure gas. This has led illogical consequence inferred depending time which exposed We use Einstein expression probability transition system derive an rate absorption. When derived used coefficient, same value found experimental techniques...

The energy transport mechanisms of a sessile-water droplet evaporating steadily while maintained on Cu substrate are compared. Buoyancy-driven convection is eliminated, but thermal conduction and thermocapillary active. dominant mode varies along the interface. Although neglected in previous studies, near three-phase line, by far larger transport, this region where most evaporation occurs.

Recent measurements of the temperature at interface an evaporating liquid have been found to be in conflict with predictions classical kinetic theory. Under 20 different experimental conditions for water evaporation, vapor was measured greater than that and this relation between interfacial temperatures is opposite predicted from When these same data were used examine statistical rate theory (SRT) expression evaporation rate, almost complete agreement found. This theoretical approach based...

The conditions are examined under which a single bubble and number of bubbles in equilibrium within closed volume liquid that is maintained at constant temperature pressure. It predicted depending on the amount gas present volume, there may be no state for or bubbles, one size, two possible sizes. In latter case, it also corresponding to larger size stable state. This contrast case an unbounded where possibility only bubble, this unstable. stability was experimentally, agreement found...

According to homogeneous nucleation theory, the spontaneous formation of a bubble occurs in liquid when thermodynamic fluctuation sufficient magnitude form at least critical size. Here we report results an experimental study bubbles near state. We examine both stability this state and predicted value radius. Photographs two simultaneously present liquid, one slightly larger than size other smaller, are presented. Subsequent photographs show grow smaller dissolve. Hence is unstable radius...

The equation traditionally used to interpret temperature programmed desorption (TPD) spectra, the Polanyi–Wigner equation, does not contain explicitly coverage and dependence necessary predict TPD spectra in several important systems including CO–Ni(111). Herein, statistical rate theory (SRT) approach is formulate equations for which are then examine reported literature molecular material properties CO–Ni(111) system have been previously established. One experimental spectrum has chosen...

We first consider the conditions under which pockets of a gaseous phase, i.e., bubble nuclei, would be in stable equilibrium roughness walls container liquid-gas solution or small, solid particles suspended liquid phase. It is shown that if there are sufficient number such then an arbitrarily large, closed volume maintained at constant temperature and pressure, these tiny nuclei can thermodynamically state when gas concentration phase only slightly greater than value contact angle small. The...

When evaporation occurs at a spherical water-vapor interface maintained the circular mouth of small funnel, studies energy transport have indicated that thermal conduction alone does not provide enough to evaporate liquid observed rate. If Gibbs model is adopted and "surface-thermal capacity" assigned value 30.6+/-0.8 kJ/(m2 K), then for experiments with interfacial temperature in range -10 degrees C< or =TLV< =3.5 C Marangoni number (Ma) 100<Ma<22,000, it was found if by both...

The statistical rate theory approach is used to derive the expression for of gas absorption by a liquid. This process involves two sequential rates−the transport from surface and bulk According theory, limiting step surface. After deriving step, it incorporated in an integral equation predicting evolution bubble evolving isothermally liquid–gas solution. accounts movement boundary diffusion problem. Statistical leads complete absorption; thus comparing predicted with set measurements, one...

Electrochemical reduction of oxygen has been studied in detail employing rotating disk and ring‐disk electrode techniques aqueous solutions various concentrations at temperatures. Analysis voltammetric results recorded the (RDE) indicates that there are two clearly defined Tafel regions low (60 mV/decade) high slopes. In general, kinetics improves slopes low‐slope region decreases slightly as basicity electrolyte solution increases. The (RRDE) were analyzed according to a simple model for...

A method is proposed for determining the surface tensions of a solid in contact with either liquid or vapor. Only an equilibrium adsorption isotherm at solid-vapor interface needs to be added Gibbsian thermodynamics obtain expressions and solid-liquid tensions, gamma[1](SV) gamma[1](SL), respectively. An relation formulated that has essential property not predicting infinite amount adsorbed when pressure equal saturation-vapor pressure. Five different systems from literature are examined,...

The statistical rate theory approach is used to derive the expression for of adsorption a nondissociating gas on solid surface. By comparing predicted with available experimental results, one central assumptions in can be examined. On basis these which theoretical predictions are found close agreement, assumption would appear valid. being agreement results throughout period, derived from an improvement over presently theories.

An isothermal decompression technique has been used to measure the pressure at which homogeneous nucleation of bubbles occurs in solutions nitrogen ethyl ether. Droplets ether–nitrogen solution were suspended a host liquid by flowing rate just countered buoyancy droplets. The system was then decompressed until occurred. presence dissolved ether observed raise extent increase corresponds closely with that previously predicted.

Absolute rate theory and the sticking probability approach have been previously examined as possible means of predicting adsorption. However, when applied to examine adsorption kinetics, they found not contain coverage pressure dependence required for several important systems including CO–Ni(111). Statistical (SRT) is being developed with objective molecular (or atomic) transport across interface between macroscopic phases in terms experimentally controllable variables material properties...

When water evaporates at high rates, recent studies indicate thermal conduction to the interface does not provide enough energy evaporate observed rate and that it is perhaps thermocapillary convection transports remaining energy. This possibility examined by applying Gibbs dividing-surface approximation develop an expression for transported along interface. this transport compared with required liquid rate, found a excess property, ``surface-thermal capacity,'' can be evaluated. A series of...

A method that has recently been used to examine the rate of molecular transport across a phase boundary—statistical theory— is extended obtain expression for single step chemical reaction. The concentration dependence newly derived leads prediction higher reaction in period immediately after begun than any previous theories and gives different physical interpretation ‘‘rate constant’’. When ions are reacting solution under near-equilibrium conditions, reduces conventional expression; further...