Vapor Pressure Data Analysis Methodology, Statistics, and Applications

A method of fitting vapor pressure temperature data to the Antoine equation is described along with a detailed statistical analysis of the fits and calculations of vapor pressures, enthalpies of vaporization, volatilities (concentration of saturated vapors), and boiling points with the Antoine constants. It is shown that the number of digits required to accurately perform vapor pressure calculations is greater than previously believed. The system permits calculation of the limits of error for any level of confidence. A program is used to analyze and plot the available vapor pressure data for diethyl malonate. Vapor pressure, Antoine equation, Volatility, Temperature, Statistics, Plotting, Enthalpy of Vaporization, Concentration of saturated vapor, Experimental methods, Diethyl malonate, Confidence limits, Confidence level.

New Method for Water Vapor Permeability Testing of Medicine Package- Electrolytic Analysis Method

Water vapor permeability testing of package material is of great significance to medicine quality insurance. Based on the latest standards of medicine package, this article briefs on testing principle of water vapor permeability testing of electrolytic analysis method and its application in the testing of medicine package materials.

Method Water Vapor Permeability

Oxygen and water vapor have obvious influence on active substance of food, pharmaceuticals and some cosmetics, which make chemical property of these products unstable. Therefore, commercial packaging usually raises demand on barrier property of specimen materials. At present, the fundamental method of water vapor permeability testing-gravimetric method is provoking criticism in terms of its test efficiency and test repeatability, etc. The expansibility of gravimetric method and whether gravimetric method will be replaced have become the focus of concern. This article presents a systematic analysis of test principle, present situation and prospect of gravimetric method.

Processing Maple Syrup with a Vapor Compression Distiller

A test of vapor compression distillers for processing maple syrup revealed that: (1) vapor compression equipment tested evaporated 1 pound of water with .047 pounds of steam equivalent (electrical energy); open-pan evaporators of similar capacity required 1.5 pounds of steam equivalent (oil energy) to produce 1 pound of water; (2) vapor compression evaporation produced a syrup equal in quality to that from a conventional open-pan evaporation plant; and (3) a central plant prodrucing 8,000 gallons of syrup per year should yield a return of 16 percent on investment. Increasing annual product output should increase the return on investment.

Water Vapor Confirmed a Major Greenhouse Gas

Water vapor is one of the most powerful greenhouse gases. As the
oceans warm, thanks to rising levels of CO2, they evaporate water
vapor more freely into the atmosphere. Similarly, as the land surface
warms, it too evaporates more water vapor into the warming atmosphere.

As the atmosphere warms, thanks to rising levels of CO2, it can hold
more water vapor.