Volume Burnett

R. N. Burnett, W. A. Lester, Jr., Computational Chemistry Reviews of Current Trends, Volume 2 J. Leszczynski, Ed., 125, World Scientific, Singapore (1997). 

Burnett, W. C., Corbett, D. R., Schultz, M., Horwitz, E. P., Chiariza, R., Dietz, M., Thakkar, A., and Fern, M., Pre-concentration of actinide elements from soils and large volume water samples using extraction chromatography, J. Radio anal. Nucl. Chem., 226, 121-127, 1997. 

Burnett, R. M. 1984 Structural investigations of hexon, the major coat protein of adenovirus. In Biological macromolecules and assemblies (Volume 1 Virus structures) (ed. F. A. Jurnak A. McPherson), pp. 377-385. New York John Wiley Sons. 

The in situ precipitation technique and transmission electron microscopy have been used to investigate the effect of DMSO on percutaneous absorption in the mouse barrier [27] and human SC [46]. Sharata and Burnette examined ultrastructural changes in mouse stratum comeum by determining the distribution of sulfide precipitates of topically applied, water-soluble tracers (Hg and Ni ) after application of enhancer [27]. For skin pretreated with DMSO, mercury and nickel precipitates were found within swollen basal stratum comeum cells as well as intercellularly and associated with the cell envelopes, but not below the stratum comeum-stratum granulosum interface. It was concluded that treatment with DMSO, as well as with other dipolar aprotic solvents such as DMF and DMA, alters the passive intercellular diffusion pathway by expanding the size of the basal stratum comeum cells, resulting in an increased free volume for tracer diffusion. 

Cole has also developed a modification of the Burnett technique, involving three measuring cells with matched volumes and shown schematically in Figure 1(b). Initially all three cells are filled with gas, the valves closed, and is measured. Cell A is then evacuated, the gas from B and C allowed to expand into A, and another measurement of e, made. The procedure is repeated cyclically, evacuating cells B, C, A, B, C in turn. The values of/before and after a complete cycle of expansions are related by... 

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... 

In an effort to determine the higher dielectric virial coefficients without determining fin. Cole and co-workers have adapted the Burnett expansion technique to dielectric measurements. A schematic figure of their apparatus is shown [Figure 1(a) ]. Initially the system is filled with gas, the valve closed and Cr measured. Volume B is then evacuated, the gas from cell A allowed to expand into B, the valve closed and Sg measured again. The process is repeated a number of times giving a series of... 

Jakubowski, E.M., McGuire, J.M., Evans, R.A., Edwards, J.L., Hulet, S.W., Benton, B.J., Forster, J.S., Burnett, D.C., Muse, W.T., Matson, K., Crouse, C.L., Mioduszewski, R.J., and Thomson, S.A., Quantitation of fluoride ion released sarin in red blood cell samples by gas chromatography-chemical ionization mass spectrometry using isotope dilution and large-volume injection, J. Anal. Toxicol., 28(5), 357-363, 2004. 

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%. 

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-... 

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. 

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. 

N <= Burnett volume ratio for the limit of zero pressure... 

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

T = absolute temperature of the gas v = specific volume of the gas V = volume of the gas Vi = Burnett sample volume Vn = Burnett expansion volume Z = gas compressibility factor p = density of the gas... 

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. 

Rock, G., R. S. Labow, C. Franklin, R. Burnett, and M. Tocchi. 1988. Plasticizer interaction with stored blood produces a toxic metabolite, mono(2-ethylhexyl) phthalate. Symposium Proceedings of the Material Research Society, Volume Date 1987, 110 767-72 cited in Chem. Abstr. CA 111(26) 239356t. 

The uncertainties of the effects of interaction of mercury vapour with the gas are overcome in the Burnett expansion method [36-bur]. This method has the further advantage that only pressure measurements are required - there is no need for mass or volume measurements. Here two different-sized vessels are connected via narrow tubing with a valve, as shown in Figure 5. 

Extractants from liquid-liquid systems such as HDEHP [di(2-ethylhexyl) or-thophosphoric acid] and CMPO/TBP (carbamoylmethylphosphine oxide derivative and tri-n-butyl phosphate) are supported on the solid material, as are newer ion-selective crown ethers (such as 4,4 (50-di-f-butylcyclohexano 18-crown-6 for Sr). Various SPE columns available commercially from Eichrom Industries have proven useful to separate radionuclides such as Sr, Tc, Ra, Ni, Pb, Am, Pu, Th, U, Np, Cm, and lanthanides. These columns usually are small (approximately 2 ml resin bed). Their effectiveness depends on their specificity for the ion that includes the radionuclide of interest, but the small volume limits the amount (i.e., less than 10 mg) of carrier that can be retained. The specificity of each product shows promise for development of procedures for sequential radionuclide analyses from a single sample aliquot. (Burnett et al. 1997, Horowitz et al. 1998)... 

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. 

Recently Hall and Eubank proposed that 3 be determined in a Burnett apparatus by mixing at constant volume two gases not necessarily initially at the same pressure. The interaction virial coefficient is then determined from the initial and final pressures, the compression factors of the pure substances, and the temperatures. It is claimed that the virial coefficients of the pure substances are not required to specify the compression factors, however, much the same information is needed. The difference between the Hall and Eubank method and other gas-mixing techniques lies in the treatment of the results for a simulated experiment the proposed analysis leads to a smaller uncertainty in - 12 ... 

An expansion method with several attractive features is that due to Burnett. This method does not require measurements of volumes, or of the amount of gas. As it does not use mercury as confining fluid the method can be used at relatively high temperatures. On the other hand, the method cannot be used in regions where F is a rapidly varying function of p, i.e. in the critical region. Initially, a quantity of gas is contained in a cell of volume Vi (Figure 6), and the temperature and pressure are measured. The gas is then allowed to expand through the valve Y into the evacuated... 

A more thorough and detailed investigation of compressibility of Freon-23 in the gaseous and liquid phase was carried out at MEI under the supervision of D. C. Raskazov and E. K. Petrov [4.3, 4.6, 4.14]. For the determination of compressibility of the gas, the researchers employed the method of successive expansion on the isotherm. Unlike the classical Burnett method, the expansion of the substance was carried out in a previously graduated piezometer (volume V ). The quantity of the substance in the piezometer was determined by weighing after freezing out the freon into a separating container. The formula for the calculation of the specific volume is... 

Belzille et al. [4.18] used a modified version of the Burnett method with three piezometers two of them had a volume of 550 cm, and the third had a volume of 183 cm. This allowed them to carry out the experiments with consid-... 

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