نتایج جستجو برای: vapor pressure

تعداد نتایج: 438036  

Journal: :The Analyst 2000
A B Dindal M V Buchanan R A Jenkins C K Bayne

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...

2015
Jae Im Jeong Sung Hyuk Lee Hugo F. Lopez

Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass...

2010
Allan H. Harvey

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...

Journal: :Journal of Research of the National Bureau of Standards Section A: Physics and Chemistry 1962

Journal: :Journal of Research of the National Bureau of Standards 1954

The examination of available vapor pressure data in the case of the methane, ethane, propane and butane halogenated refrigerants, allowed recommendations of standard equations for this property. In this study, three new models include a general correlation; a substance-dependent correlation and an artificial neural network (ANN) approach have been developed to estimate the saturated vapor press...

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...

Journal: :Journal of Chemical Education 1997

Journal: :Journal of Vacuum Science and Technology 1981

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