Gas measurements

Avogadro s Hypothesis Equal volumes of gases, measured at the same temperature and pressure, contain equal numbers of molecules. 

Figure 5. Total ion current from different gases measured on blanked-off first electrode. Rare gases show much lower negative currents. Negative current deficiency believed caused by electrons...

Livingston G, Hutchinson G. Enclosure-based measurement of trace gas exchange applications and sources of error. In Matson PA, Harris RC, editors. Biogenic Trace Gases Measuring Emissions from Soil and Water. Osney Mead, Oxford Blackwell Sciences Ltd. 1995. pp. 14r-51. 

With modem equipment it is now possible to measure oxygen consumption and carbon dioxide production breath by breath. Alternatively, for long-term studies, the volunteer can be enclosed in a room and the changes in content of the gases measured. For resting subjects and for patients, this is not necessary a simple hood over the head may be sufficient to allow measurement of oxygen uptake and carbon dioxide production, if precision is not required. 

Figure 1.10 Mass spectra of different gases measured by F. W. Aston in 1920. (H. Kienitz (ed.), Massen-...

Avogadro s Law Equal volumes of all gases measured under the same conditions of temperature and pressure contain equal numbers of molecules. 

The catalyst chosen was packed into a hard glass combustion tube, heated to the desired temperature, and the gases, measuring some 1500 e.c. in toto, were continuously circulated throughout the system. Any combination to form water was measured by observing the fall in pressure. The majority of the experiments were carried out with porcelain 1 as catalyst., and it was found that the rate of combination of hydrogen and oxygen in electrolytic gas is directly proportional to the pressure of the dry gas. 

The subcommittee did not find information on the effects of hyperbaric conditions on Draeger-tube (tubes that measure concentrations of specific gases) measurements and recommends that research be conducted to determine the effect of increased pressure on Draeger-tube measurements. The results of that... 

An adsorption kinetic model was developed to evaluate the adsorption rates of five pure gases (Nj, O2, Ar, CO, and CH4) on a Takeda-3A CMS over a wide range of pressures up to ISatm. The kinetic characteristics of adsorption on the CMS were studied by using the adsorption equilibrium of five pure gases measured at three different temperatures and their physical properties. Since the diffiisional time constants of all the components showed much stronger dependence of pressure than those expected by the traditional Darken relation, a structural diffusion model was applied to predict the strong pressure dependence. The proposed model successfully predicted the dif ional time constant up to high pressure on the CMS. 

The international standard ISO 5024—Petroleum Liquids and Gases— Measurement—Standard Reference Conditions published by the International... 

Blood gases Measurements of arterial pOa, pCOa, and pH Evaluates adequacy of ventilation changes typically require severe functional deficits... 

Arterial oxygen pressure (Pa02) and saturation (Sa02) may be measured invasively by obtaining an arterial blood sample. Arterial blood gases measured by conventional arterial sampling are considered... 

The composition of dew collected from a Teflon surface was compared to summer rainwater concentrations at a site in Warren, Michigan. This comparison showed that natural dew is similar to rainwater with the exception that dew has much higher concentrations of Ca and Cl and much lower acidity. Dry deposition rates of several species were measured to artificially-generated dew and a dry surface. It was found that deposition rates were 2 to 20 times greater to the artificial dew than to the dry surface indicating that the presence of dew enhances both the retention of dry deposited particles and the absorption of water soluble gases. Measurement of the atmospheric concentrations of the depositing species permitted the calculation of deposition velocities for particulate... 

Answer Since both C2H2 and O2 are gases measured at the same temperature and pressure, according to Avogadro s law their reacting volnmes are related to their coefficients in the balanced eqnation that is, 2 L of C2H2 react with 5 L of O2. Knowing this ratio we can calcnlate the volnme (in liters) of O2 that will react with 2.64 L... 

Figure 11. Diffusion coefficients for noble and selected active gases measured in water at 25°C, shown as a function of mass (after Jahne et...

Figure 1 shows the effects at pH 9 of variable RNO concentration on G( —RNO)440, calculated from linear portions only of dose-yield plots, for RNO solutions saturated with different gases. Measurements at high RNO concentration were difficult to obtain accurately since they involved small differences between large optical densities and at very low RNO concentrations curvature was noticeable in dose vs. bleaching curves at shorter irradiation times. Experiments at concentrations higher than 10-8M RNO were conducted and G( — RNO)440 was strongly dependent upon 02 concentration but values were not very reproducible. 

The CMB model combines the chemical and physical characteristics of particles or gases measured at the sources and the receptors to quantify the source contributions to the receptor (Winchester and Nifong 1971 Miller et al. 1972). CMB is a method for the solution of the set of equations (26.9) to determine the unknown sj. The source profiles atj, that is, the fractional amount of the species in the emissions from each source type, and the receptor concentrations, with appropriate uncertainty estimates, serve as input to the CMB model. We start by analyzing the case where one particulate sample is available. The first assumption of CMB is that all sources contributing to the measured concentrations c, in the receptor have been identified. Each measured concentration c,- can then be expressed as the sum of the true value c and a random error e, ... 

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