the pressure drop of refrigerant r-134a flow boiling inside a horizontal tube has been investigated experimentally. the test set-up which was used in this investigation is a well instrumented vapor compression refrigeration system. these instruments are thermocouples, flow meter, pressure gauges and the pressure drop measuring apparatus. this system consisted of three electrically heated evapor...

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...

We examine, using (211)-dimensional Monte Carlo simulations, the roughening behavior of a reemission model for chemical vapor deposition. We find that, for pure first-order reemission, the interface roughens logarithmically with time and that the scaling exponents are, for most sets of conditions, close to the exponents of the Edwards-Wilkinson model (a50, b50, and z52). We compare our results ...

Assuming a reemission model, we have studied, in detail, the effect of sticking coefficient on the morphology evolution in low-pressure chemical vapor deposition processes. We have shown that the surface morphology changes from a self-affine fractal to a columnarlike morphology with increasing sticking coefficient, which agrees qualitatively with experimental observations.

This paper presents a two-dimensional analytical model for low-temperature cylindrical heat pipes. A closed-form solution which incorporates liquid±vapor interfacial hydrodynamic coupling and non-Darcian transport through the porous wick for the ®rst time, is obtained for predicting the vapor and liquid velocity and pressure distributions. In addition, the steady-state vapor and wall temperatur...

Measurements of the vapor pressure in the range 291 to 341 K and of the evaporation coefficient of liquid glycerol are reported. In contrast to the results of other authors a unit evaporation coeff lcient is found. The higher vapor pressures given by several other authors are shown to be due to minute traces of water. Using our low temperature data and the data of reliable investigations at hig...

Successfully integrating graphene in standard processes for applications in electronics relies on the synthesis of high-quality films. In this work we study Low Pressure Chemical Vapor Deposition (LPCVD) growth of bilayer graphene on the outside surface of copper enclosures. The effect of several parameters on bilayer growth rate and domain size was investigated and high-coverage bilayers films...

systematic studies on the vapor-liquid equilibria (vle) and conductometric properties of aqueous solutions of model surface-active ionic liquid 1-dodecyl-3-methylimidazolium bromide ([c12mim]br) are performed in the absence and presence of a large series of electrolytes in order to achieve a deeper understanding about the molecular mechanism behind the specific salt effect on the aggregation be...

in this study, a generalized equation is presented to calculate vapor pressure of pure substances as a function of reduced temperature, critical pressure, and acentric factor. with the presented model, vapor pressures have been calculated and evaluated with nist data bank for 70 pure substances for about 14000 data points, and the overall average absolute percentage deviation has been only 0.78...

A new dual-fluid concept was studied that could eventually find application for cold-gas propulsion for small space satellites or other constant flow applications. In basic form, the concept uses two different refrigerant working fluids, each having a different saturation vapor pressure. The higher vapor pressure refrigerant remains in the saturation phase and is used to pressurize the lower sa...