We tested, compared and modified three models of stomatal conductance at the leaf level in a forest ecosystem where drought stress is a major factor controlling forest productivity. The models were tested against 2 years (1999 and 2000) of leaf-level measurements on ponderosa pine (Pinus ponderosa Dougl. ex Laws.) growing in the Mediterranean climate of California, USA. The Ball, Woodrow and Be...

Using a GC headspace measurement technique, the vapor pressure of TATP was determined over the temperature range 12 to 60 8C. As a check on the experimental method, TNT vapor pressure was likewise computed. Values for TNT are in excellent agreement with previous published ones. For TATP the vapor pressure was found to be ~7 Pa at ambient conditions. This value translates to a factor of 10 more ...

The establishment of drug vapor pressure reference values provides valuable information in the development of vapor sensing devices for drug detection. The purpose of this work was to determine equilibrium headspace vapor pressures for commercial and illicit drug samples for use in such applications. Samples of cocaine, both free base and hydrochloride forms, and heroin hydrochloride were evalu...

A combination of classical thermodynamics and molecular theory was used to calculate the enhancement factor (ratio of vapor-phase partial pressure to saturated vapor pressure) for liquid mercury in equilibrium with air at standard atmospheric pressure at temperatures from 0 ◦C to 40 ◦C. The enhancement factors range from 1.0025 at 0 ◦C to 1.0016 at 40 ◦C. This enhancement is too small in magnit...

Humidification process is one of the applications of membrane contactor in which partial pressure of a vapor in the gas stream increases. In this study, two different polyethersulfone and polyetherimide hollow fiber membranes were fabricated and characterized by various test methods and their performance in humidification process under different operating conditions was investigated. The PES me...

The first operation of GEM gas gain elements in negative ion gas mixtures is reported. Gains up to several thousand were obtained from single-stage GEMs in CS 2 vapor at low pressure, and in mixtures of CS 2 with Argon and Helium, some near 1 bar total pressure.