Carbon dioxide concentrations

Climate and Environmental Factors. The biomass species selected for energy appHcations and the climate must be compatible to faciUtate operation of fuel farms. The three primary climatic parameters that have the most influence on the productivity of an iadigenous or transplanted species are iasolation, rainfall, and temperature. Natural fluctuations ia these factors remove them from human control, but the information compiled over the years ia meteorological records and from agricultural practice suppHes a valuable data bank from which to develop biomass energy appHcations. Ambient carbon dioxide concentration and the availabiHty of nutrients are also important factors ia biomass production. 

For some high growth-rate biomass species, the carbon dioxide concentration in the air among the leaves of the plant often is considerably less than that in the surrounding atmosphere. Photosynthesis may be limited by the carbon dioxide concentrations under these conditions when wind velocities are low and insolation is high. 

Carbon. Most of the Earth s supply of carbon is stored in carbonate rocks in the Hthosphere. Normally the circulation rate for Hthospheric carbon is slow compared with that of carbon between the atmosphere and biosphere. The carbon cycle has received much attention in recent years as a result of research into the possible relation between increased atmospheric carbon dioxide concentration, most of which is produced by combustion of fossil fuel, and the "greenhouse effect," or global warming. Extensive research has been done on the rate at which carbon dioxide might be converted to cellulose and other photosyntheticaHy produced organic compounds by various forms of natural and cultivated plants. Estimates also have been made of the rate at which carbon dioxide is released to soil under optimum conditions by various kinds of plant cover, such as temperature-zone deciduous forests, cultivated farm crops, prairie grassland, and desert vegetation. 

Carbon Dioxide Transport. Measuring the permeation of carbon dioxide occurs far less often than measuring the permeation of oxygen or water. A variety of methods ate used however, the simplest method uses the Permatran-C instmment (Modem Controls, Inc.). In this method, air is circulated past a test film in a loop that includes an infrared detector. Carbon dioxide is appHed to the other side of the film. AH the carbon dioxide that permeates through the film is captured in the loop. As the experiment progresses, the carbon dioxide concentration increases. First, there is a transient period before the steady-state rate is achieved. The steady-state rate is achieved when the concentration of carbon dioxide increases at a constant rate. This rate is used to calculate the permeabiUty. Figure 18 shows how the diffusion coefficient can be deterrnined in this type of experiment. The time lag is substituted into equation 21. The solubiUty coefficient can be calculated with equation 2. 

Carbon dioxide concentrations vary depending on the beverage formulation. Cola and lemon—lime beverages normally contain more carbonation than berry flavored or other citms beverages. 

The processes using physical absorption require a solvent circulation proportional to the quantity of process gas, inversely proportional to the pressure, and nearly independent of the carbon dioxide concentration. Therefore, high pressures could favor the use of these processes. The Recitsol process requires a refrigeration system and more equipment than the other processes. This process is primarily used in coal gasification for simultaneous removal of H2S, COS, and CO2. 

A hybridoma can live indefinitely in a growth medium that includes salts, glucose, glutamine, certain amino acids, and bovine serum that provides essential components that have not been identified. Serum is expensive, and its cost largely determines the economic feasibihty of a particular ciilture system. Only recently have substitutes or partial replacements for serum been found. Antibiotics are often included to prevent infection of the culture. The pH, temperature and dissolved oxygen, and carbon dioxide concentration must be closely controlled. The salt determines the osmotic pressure to preserve the integrity of the fragile cell. 

The instrumental analyzer procedure, EPA Method 3A, is commonly used for the determination of oxygen and carbon dioxide concentrations in emissions from stationary sources. An integrated continuous gas sample is extracted from the test location and a portion of the sample is conveyed to one or more instrumental analyzers for determination of O9 and CO9 gas concentrations (see Fig. 25-30). The sample gas is conditioned prior to introduction to the gas analyzer by removing particulate matter and moisture. Sampling is conducted at a constant rate for the entire test run. Performance specifications and test procedures are provided in the method to ensure reliable data. 

Figure 4-463. Effect of carbon dioxide concentration on corrosion rate. (From Ref. [211J.)...

Gal-Or and Hoelscher (G5) have recently developed a fast and simple transient-response method for the measurement of concentration and volumetric mass-transfer coefficients in gas-liquid dispersions. The method involves the use of a transient response to a step change in the composition of the feed gas. The resulting change in the composition of the liquid phase of the dispersion is measured by means of a Clark electrode, which permits the rapid and accurate analysis of oxygen or carbon dioxide concentrations in a gas, in blood, or in any liquid mixture. 

Such changes in the pH are sensed by the inner glass electrode. The overall cell potential is thus determined by the carbon dioxide concentration in the sample ... 

Figure 2a. Carbon dioxide concentrations in the atmosphere have varied over the glacial cycles of the earth s history, with high vjues at of around 300 during the interglacial period approximately 130,000 years ago...

Carbon dioxide has been measured at more that 30 stations, and an annual fluctuation of atmospheric carbon dioxide concentration was observed at all (10), However, the magnitude and timing of the fluctuations varied with geographic location (11), At Mauna Loa observatory, the concentration of atmospheric CO2... 

Oechel, W. C. and Strain, B. R. (1985). Native species responses to increased carbon dioxide concentration. In "Direct Effects of Increasing Carbon Dioxide on Vegetation" (B. R. Strain and J. D. Cure, eds), pp. 117-154. Springfield, VA, U.S. Department of Energy. 

Fig. 11-9 (a) The vertical distributions of alkalinity (Aik) and dissolved inorganic carbon (DIC) in the world oceans. Ocean regions shown are the North Atlantic (NA), South Atlantic (SA), Antarctic (AA), South Indian (SI), North Indian (NI), South Pacific (SP), and North Pacific (NP) oceans. (Modified with permission from T. Takahashi et ah, The alkalinity and total carbon dioxide concentration in the world oceans, in B. Bolin (1981). Carbon Cycle Modelling," pp. 276-277, John Wiley, Chichester.)... 

Bacastow, R. B. and Keeling, C. D. (1981). Atmospheric carbon dioxide concentration and the observed airborne fraction. In "Carbon Cycle Modeling" (B. Bolin, ed.), pp. 103-112. Wiley, New York. 

Edmond, J. M. (1970). High precision determination of titration alkalinity and total carbon dioxide concentration of sea water by potentiometric titration. Deep-Sea Res. 17, 737-750. 

Nakazawa, T., Murayama, S., Miyashita, K., Aoki, S. and Tanaka, M. (1992). Longitudinally different variations of lower tropospheric carbon dioxide concentrations over the North Pacific Ocean, Tellus, Ser. B, 44,161-172. 

Wigley, T. M. L. (1993). Balancing the carbon budget Implications for projections of future carbon dioxide concentration changes, Tellus 45B, 409-425. 

Farquhar, G.D., O Leary, M.H. Berry, J. A. (1982). On the relationship between carbon isotope discrimination and the intercellular carbon dioxide concentration in leaves. Australian Journal of Plant Physiology, 9, 121-37. 

The model gives seml-quantltatlve data about the carbon dioxide concentration In the paint film during curing. The possibilities of the model are Illustrated by using It for calculating the Influence which different parameters have on the carbon dioxide concentration. 

The formation of carbon dioxide depends on both the isocyanate and water concentrations in the paint film. The carbon dioxide concentration in the paint film depends on the diffusion coefficient, the film thickness and the difference in carbon dioxide concentration between paint film and gas phase ... 

Using known and estimated parameters, calculations have been performed with regard to the decrease of isocyanate and the carbon dioxide concentration in the paint film. 

The carbon dioxide concentration in the film can also be controlled by other physical and chemical parameters, for instance the type of catalyst (influencing the reaction rate constants) or the use of more hydrophobic resin (influencing the water concentration). 

Figure 9. Carbon dioxide concentration in the paint film, calculated with the aid of the mathematical model, ki = 0.02 cm /mmole.s ka 0.06 cm /mmole.s...

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