carbon dioxide

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carbon dioxide

 
an odorless, colorless gas, CO2, resulting from oxidation of carbon, formed in the tissues and eliminated by the lungs; used in some pump oxygenators to maintain the carbon dioxide tension in the blood. It is also used in solid form; see carbon dioxide snow and carbon dioxide slush.
carbon dioxide combining power the ability of blood plasma to combine with carbon dioxide; indicative of the alkali reserve and a measure of the acid-base balance of the blood.
carbon dioxide content the amount of carbonic acid and bicarbonate in the blood; reported in millimoles per liter.
carbon dioxide–oxygen therapy administration of a mixture of carbon dioxide and oxygen (commonly 5 per cent CO2 and 95 per cent O2 or 10 per cent CO2 and 90 per cent O2); used for improvement of cerebral blood flow, stimulation of deep breathing, or treatment of singultation (hiccupping). Carbon dioxide acts by stimulating the respiratory center; it also increases heart rate and blood pressure. Therapy is given for 6 minutes or less with a 5 per cent mixture and 2 minutes or less with a 10 per cent mixture. Potential adverse effects include headache, dizziness, dyspnea, nausea, tachycardia and high blood pressure, blurred vision, mental depression, coma, and convulsions.
carbon dioxide slush solid carbon dioxide combined with a solvent such as acetone, and sometimes also alcohol; used as an escharotic to treat skin lesions such as warts and moles and as a peeling agent in chemabrasion.
carbon dioxide snow the solid formed by rapid evaporation of liquid carbon dioxide, giving a temperature of about −79°C (−110°F). It has been used in cryotherapy to freeze the skin, thus producing local anesthesia and arrest of blood flow. See also carbon dioxide slush.

car·bon di·ox·ide (CO2),

the product of the combustion of carbon with an excess of oxygen; in concentrations not less than 99.0% by volume of CO2.

carbon dioxide

n.
A colorless, odorless, incombustible gas, CO2, that is formed during respiration, combustion, and organic decomposition, is an essential component in photosynthesis, and is used in food refrigeration, carbonated beverages, inert atmospheres, fire extinguishers, and aerosols. Also called carbonic acid gas.

carbon dioxide

CO2 Physiology A metabolic byproduct of carbohydrate metabolism; it accumulates in tissues, is released to the blood in veins, and is eliminated via the lungs

car·bon di·ox·ide

(CO2) (kahr'bŏn dī-oks'īd)
The product of the combustion of carbon with an excess of air; in concentrations not less than 99.0% by volume of CO2, used as a respiratory stimulant.

carbon dioxide

A compound in which an atom of carbon is linked to two atoms of oxygen (CO2 ). Carbon dioxide is a colourless, odourless gas and is one of the chief waste products of tissue metabolism.

carbon dioxide

a colourless, odourless gas, heavier than air, produced in respiration of organisms, and utilized to form sugars in PHOTOSYNTHESIS. Formula: CO2 .

Carbon dioxide

A heavy, colorless gas that dissolves in water.
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hypercapnia

The presence of a raised carbon dioxide content or tension in a milieu (e.g. blood, tears). Contact lens wear tends to give rise to this condition, especially lenses of low gas transmissibility. See acidosis.

car·bon di·ox·ide

(CO2) (kahr'bŏn dī-oks'īd)
Product of the combustion of carbon with an excess of oxygen.
References in periodicals archive ?
As R-134a and R-744 have different specific volumetric heat capacities, the suction volumes have to be chosen respectively (based on the ratio of suction volumes of mechanical swash-plate-piston compressors) [12].
For simultaneous heating and cooling of water with a R-744 cycle the optimum ratio ranged from 1.6 to 1.9.
The recovered R-744 in the Thermo King CryoTech systems is obtained as a by-product from industrial processes that would otherwise have been released into the atmosphere.
Pull down of an empty box can be up to four times faster with R-744, making it an excellent choice for distribution operations with a high number of door openings.
Based on this approach, flow coefficients for the investigated geometries are experimentally identified for the different media, R-744, R-729, and ARAL 4005.
Three different test prototype valves with cone-, ball-, and slide-valve geometries (Figure 3) were investigated using three different fluids: R-744, R-729, and ARAL 4005.
The main difference between the R-744 platform designs in comparison with the current refrigerant compressor technology is the very high working pressure, which affects the housing design in terms of ensuring safety and preventing leakage to the ambient environment.
Finally, other considerations were taken into account and analyzed to give an overall vision of the feasibility of a compressor for light commercial appliances working with R-744.
The high-efficiency refrigeration systems utilizing low GWP refrigerants, including R-1234yf, R-717, and R-744, can drastically reduce carbon dioxide emissions as compared to the baseline R-404A multiplex DX refrigeration system.
Life cycle climate performance (LCCP) of mobile air-conditioning systems with HFC-134a, HFC-152a and R-744. Mobile Air Conditioning Summit, Washington, D.C., 14-15 April 2004.
The thermodynamic and thermophysical properties of R-744 in the calculations are obtained from the database REFPROP v.
Adverse Affects of Refrigerants on the Environment from the United Nations Environment Program (UNEP-2006) Refrigerants ODP GWP (100 Year Time Horizon) R-12 (CFC) 1.00 10,890 R-22 (HCFC) 0.050 1810 R-134a (HFC) 0 1430 R-744 or [CO.sub.2] (nature 0 1 friendly) Comparing GWPs and ODPs of R-744 to R-134a, R-22, and R-12 in Table 1, one can find that more research and application must be established to further the progress of [CO.sub.2] as an eco-friendly refrigerant.