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Burnett volume ratio

N <= Burnett volume ratio for the limit of zero pressure... [Pg.305]

Nr = Burnett volume ratio for the Burnett rth expansion P = pressure of the gas r = Burnett expansion number R = gas constant... [Pg.305]

Owing to the cyclic procedure, the density ratio R differs from (2/3) only by terms which are quadratic or higher powers of the relative volume differences between cells. The two main advantages of this modification over the standard Burnett technique are first, three values of c, are taken at each density second, the volume ratio can be determined to a few parts in 10 independently of the dielectric measurements. Values of Be obtained... [Pg.50]

Equation 2 they are the density virials (B ), the volume ratio (N), and the initial density (p0). The theory of the Burnett method is presented in considerably more detail in Refs. 3,4,5, 6, and 7. [Pg.292]

The results themselves have a subtlety associated with their interpretation owing to the presence of the volume-ratio parameter and, optionally, the initial density parameter. The Burnett equations have more flexibility to fit Burnett data than only a density series to PVT data. The statistical uncertainties reflect the quality of the experimental data relative to the particular model used to describe the experiment. The estimation of accuracy for Burnett results is necessarily somewhat subjective since the effect of systematic errors on parameter values is not explicit in nonlinear equations, such as the Burnett equations. Accuracy, however, can be estimated from a study of the effects of systematic errors in computer model calculations and from the magnitude of the change in the volume-ratio value determined with nonideal and nearly ideal gases. For these reasons, we include such information along with our virial coefficient results for ethylene. [Pg.292]

High precision is especially hard to obtain in measurements on vapours. Pressure ranges in expansions are restricted by proximity to saturation conditions, and high-accuracy measurements of low pressures are difficult. Adsorption also complicates studies on vapours. For example, in measurements by the Burnett method on pure Ar and Kr near saturation, Weir et al. determined the effect of adsorption in their copper apparatus by performing experiments in vessels of different surface-to-volume ratios. Corrections for adsorption first became significant at temperatures at which the saturation pressure was just in excess of atmospheric, and rose rapidly at lower temperatures. For Ar at its triple point, where the saturation pressure is 70 kPa and B = — 280 cm mol, the correction due to adsorption was 8 cm mol. Hall and Eubank recommend that Burnett measurements be combined with isochoric data to avoid systematic errors due to adsorption. [Pg.204]

Expansion methods are often used for measuring gas densities. In these methods, a sample is expanded from a small volume to a larger volume (where the ratio of volumes is accurately known), holding the temperature constant and measuring the pressure ratio. Typically, multiple expansions are used (a successive expansion technique known as the Burnett method is popular), with the final state being at a pressure sufficiently low that the density is accurately known by other means (such as correction of the ideal-gas law by the second virial coefficient). The Burnett expansion method may achieve uncertainties in density as low as 0.01%. [Pg.22]

Pu-Xe dating. Decay of Pu can be used as a chronometer of the first 100 Ma for some specific meteorite parent bodies. Both Pu and the LREE tend to be concentrated in refractory minerals like phosphates. Which LREE is the best proxy for Pu Various authors have suggested Nd (Lugmair and Marti 1977), Sm (Jones and Burnett 1987), or Pr or Ce (Boynton 1978). There are no neutron-induced reactions that produce a rare gas from any of the LREE, but all of these, particularly Nd, do produce the light xenon isotopes like Xe and Xe through cosmic-ray-induced spallation reactions (Wider 2002, this volume). In fact, in many cases, the LREE (and presumably Pu), are probably not fractionated much from each other. Hence, if the cosmic ray dose (i.e., the cosmic ray exposure age) is known, and the production rate of isotopes like " Xe and Xe is also known, then the abundance of the LREE can be calculated. Then the ratio of Xe244 (Pu-... [Pg.119]

Under conditions of intermittent illumination, when the alternating light and dark periods are equal, the ratio of the rate to that with steady illumination is 1/V2 when Tand is J when T r. For intermediate values of Tjr relative veilues of the rate have been calculated and tabulated (Mel-viUe and Burnett, chapter 3, part 4, in "Technique of organic chemistry" volume VIII, Interscience, 1953). In particular the values given in table 4 are predicted. [Pg.460]


See other pages where Burnett volume ratio is mentioned: [Pg.21]    [Pg.85]    [Pg.291]    [Pg.292]    [Pg.131]   
See also in sourсe #XX -- [ Pg.295 ]




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