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)

Etymology: L, carbo + Gk, dis, twice, oxys, sharp
a colorless, odorless gas produced by the oxidation of carbon; also a "greenhouse" gas. Carbon dioxide, as a product of cell respiration, is carried by the blood to the lungs and is exhaled. The acid-base balance of body fluids and tissues is affected by the level of carbon dioxide and its carbonate compounds. Solid carbon dioxide (dry ice) is used in the treatment of some skin conditions. Normal adult blood levels of carbon dioxide are 23 to 30 mEq/L or 23 to 30 mmol/L (SI units).

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.

carbon dioxide

an odorless, colorless gas, CO2, resulting from oxidation of carbons, formed in the tissues and eliminated by the lungs; used with oxygen to stimulate respiration and in solid form (carbon dioxide snow—see below) as an escharotic, as a gas to euthanize laboratory rabbits and rodents.

carbon dioxide anesthesia
exposure of pigs for 45 seconds in a mixture of 60 to 70% CO2 in air is an adequate pre-slaughter anesthetic for pigs.
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 dissociation curve
a graph demonstrating the relationship between the blood content of CO2 and the Pco2.
carbon dioxide narcosis
respiratory acidosis.
carbon dioxide snow
solid carbon dioxide, formed by rapid evaporation of liquid carbon dioxide; it gives a temperature of about −110°F (−79°C), and is used as an escharotic in various skin diseases. Called also dry ice.
carbon dioxide tension
the partial pressure of carbon dioxide in the blood; noted as Pco2 in blood gas analysis. See also respiration.
carbon dioxide transport
carbon dioxide passes from tissues to blood by diffusion, in the blood by solution and via reactions within plasma and erythrocytes, from blood to pulmonary alveoli by diffusion.
References in periodicals archive ?
Less attention has been given to low-pressure working fluids in the literature for ejector cooling cycles compared with R744 due to their lower work recovery potential.
Elbel and Hrnjak [6] were the first researchers to publish experimental results of introducing a variable two-phase ejector to a transcritical R744 system by installing a needle in the motive nozzle to control the motive nozzle throat diameter.
Experimental and numerical investigation of the influence of the two-phase ejector geometry on the performance of the R744 heat pump," International Journal of Refrigeration, 35(6): 1617-1625, 2012.
R744 has been subjected to extensive tests as a substitute for R134a.
5 million test kilometers completed, the Modine R744 air conditioning heat exchangers are a proven technology.
R744 has some very attractive properties, which makes it destined to be used as a working fluid.
Peter Neksa has already proved the advantages of using R744 for water and space heating applications.
It has already been derived that the thermodynamic and the transport properties of R744 are comparable with other refrigerants.
Figure 1 shows an operating range for the evaporator temperature from -55[degrees]C to 25[degrees]C for R744, as compared to -1[degrees]C to 265[degrees]C for R718, and -40[degrees]C to 105[degrees]C for R717.
Compared to R717 and R718, R744 always shows the best COP in the temperature range -55[degrees]C to -35[degrees]C, for the temperature lift of up to around 55 K.
The volume flow rate of R744 is considerably lower than that of other refrigerants (Figure 2), which makes it ideal for miniaturization.
Studies comparing R744 with other refrigerants have shown that the risk of the high pressure in a R744 system is negated by the fact that the energy contained in the system is relatively lower than that in a R-22 system owing to the lower volume and refrigerant charge.