Low temperature vacuum sublimation refrigerators on carbon dioxide as working fluid

Carbon dioxide as working fluid for medium and high-temperature concentrated solar thermal systems

This paper explores the benefits and drawbacks of using carbon dioxide in solar thermal systems at medium and high operating temperatures. For medium temperatures, application of CO2 in non-imaging-optics based compound parabolic concentrators (CPC) combined with evacuated-tube collectors is studied. These collectors have been shown to obtain efficiencies higher than 40% operating at around 200...

Temperature and pressure effects on solubility in supercritical carbon dioxide and retention in supercritical fluid chromatography

Solubilities of some polycyclic aromatic hydrocarbons (PAHs) in supercritical carbon dioxide were measured with a procedure based on a direct on-line combination of a saturation cell to a flame ionization detector. Acenaphthene, anthrance and chrysene were selected as the test solutes. A method was developed and evaluated which enables the measurement of the contribution of solute vapor pressur...

Vetiver Oil Extraction Optimization Using Supercritical Carbon Dioxide Fluid

The Carbon Dioxide Tension of Cerebrospinal Fluid

The COz tension is a necessary factor in determining the acidbase equilibrium of the blood. It has been determined for blood both directly, and indirectly through CO2 of the alveolar air. The blood, because of oxidation, reduction, forced breathing, and stasis through constriction of the veins, undergoes variations in the COz tension. Does the cerebrospinal fluid which exists in a more isolated...

The Sublimation of Ice in Vacuum

A n a c c o u n t is g iven of e x p e r i m e n t s on t h e r a t e of s u b l i m a t i o n of ice in v a c u u m a n d in t he p r e sence of a sma l l a m o u n t of air. T h e r e su l t s s h o w t h a t t h e g a s k ine t i c a c c o m o d a t i o n coef f ic ien t of t h e ice b e t w e e n 4 0 a n d 6 0 ° C lies n e a r u n i t y . Also i t a p p e a r s t h a t t h e m a x i m u m s...