Barth number

The preceding discussion shows that the sampling efficiency for thin L-shaped probes is a function of two parameters the deviation from the isokinetic conditions and the response of the particles to the deflection of the fluid streamlines upstream of the sampler. The deviation from the isokinetic conditions is a function of the velocity ratio (U/Uq), whereas the particle response is a function of the ratio of particle inertia to fluid drag. This ratio in a dimensionless form is known as the particle inertia parameter, the Stokes number, or the Barth number (K), defined as ... 

K particle inertia parameter based on probe radius (also called Stokes number or Barth number)... 

The feasibility of partial synthesis has been demonstrated in the course of structural confirmation of a great number of betaxanthins. Due to incomplete hydrolyses, residual betanin and isobetanin may also accompany the respective target betaxanthin. Most importantly, the purification of betalamic acid does not appear to be possible because it exhibits both amino and aldehyde functions (Stintzing, unpublished observations), resulting in self-condensation. Therefore, data by Barth and co-workers reporting NMR data on purified betalamic acid should be carefully interpreted. ... 

In the cladoceran Daphnia magna, about 90% of the total body lead burden is adsorbed to the exoskeleton (Berglind et al. 1985). In animals with a vertebral column, total amounts of lead tend to increase with age. By far the most lead is bound to the skeleton, especially in areas of active bone formation (Barth et al. 1973 Tsuchiya 1979 USEPA 1980 Hejtmancik et al. 1982 Mykkanen etal. 1982 Peter and Strunc 1983 De Michele 1984 Eisler 1984 Berglind etal. 1985 Marcus 1985). The retention of lead stored in bone pools poses a number of difficulties for the usual multicompartmental loss-rate models. Some lead in bones of high medullary content, such as the... 

As analytical techniques have been consistently improved in recent years, the number of boron isotope studies has increased rapidly. Reviews have been given by Barth (1993) and by Palmer and Swihart (1996). The total boron isotope variation documented to date is about 90%c. 5 B-values are generally given relative NBS boric acid SRM 951, which is prepared from a Searles Lake borax. This standard has a B/ °B ratio of 4.04558 (Palmer and Slack 1989). 

For statistical analysis it is necessary to prepare and to measure each standard at least twice. In routine analysis, carried out according to carefully prepared guidelines, confidence limits are P = 0.95, based on the standard distribution. In all other cases, especially in solving discrepancies between analytical results or for preparing instructions, confidence limits of F = 0.95 or F = 0.99, based on the t distribution, are used. The confidence intervals decrease somewhat more as the number of measurements increases, up to about 6. Above this number the effect is negligible. It can be shown that at a given number of measurements the confidence limit of the final result will be at its minimum if the number of calibration standards equals the number of sample measurements (Weitkamp and Barth, 1976). 

An alternative to Hartree-Fock theory is density-functional (DF) theory in which certain elements in the Hamiltonian are evaluated at fixed points directly from the electron densities at those points. This can circumvent the need for calculating the enormous numbers of electron-electron repulsion integrals encountered in Hartree-Fock calculations. We here briefly describe density-functional theory based upon reviews by von Barth (1986) and Srivastava and Weaire (1987). 

There are a number of model exchange-correlation functionals for the ground-state. How do they perform for ensemble states Recently, several local density functional approximations have been tested [24]. The Gunnarsson-Lundqvist-Wilkins (GLW) [26], the von Barth-Hedin (VBH)[25] and Ceperley-Alder [27] local density approximations parametrized by Perdew and Zunger [28] and Vosko, Wilk and Nusair (VWN) [29] are applied to calculate the first excitation energies of atoms. 

SQUIDs have been used in a large number of experiments where the detection of small magnetic fields is crucial. Some interesting cases include the study of magnetic fields from human brains associated with mental disorders (Barth et ai, 1984), the detection of gravitational waves (Clarke, 1986), and fluctuations in the earth s magnetic field related to geothermal effects (Clarke, 1983), etc. 

The characterization of the role of boron in biological systems in general can be found in a recent review by Linse et al. (2011). As for BNCT, at present, a huge number of reviews, collections of papers, trial reports, etc., devoted to its special aspects are published (Alam et al. 1989 Barth 2003 Barth et al. 1990, 1992, 1999, 2005 Bendel 2005 Calabrese et al. 2012 Coderre and Morris 1999 ... 

Characterization of PVA by SEC has closely followed the advances in column and detection technology. Aqueous SEC, in particular, presents a number of challenges as a result of frequently encountered secondary, non-size exclusion effects. These effects, common to aqueous SEC, have been reviewed by Barth (12). 

Sect. 1.4. A number of books specializing on the techniques of polymer characterization are White JR (1989) Polymer Characterization. Chapman and Hall, New York. Barth HG, Mays JW (1991) Modem Methods of Polymer Characterization. Wiley-Interscience, New York. Compton TR (1989) Analysis of Polymers An Introduction. Pergamon Press, New York. Craver CD (1983) Polymer Characterization. Am Chem Soc Washington DC (Advances in Chemistry Series 203). 

Baldwin B, Barth TJ. A one-equation turbulence model for high Reynolds number wall-bounded flows. NASA Technical Memorandum 102847 1990. 

The successful applications of GPC to aqueous polymer solutions are few in number. Salt-exclusion effects have been examined by Rinaudo and co-workers, who found that the elution peak was dependent on sample concentration and ionic strength for polyelectrolytes. The universal calibration was valid as soon as the ionic strength exceeded 5 x 10 molar, when screening of electrostatic repulsions was achieved. Similar observations were made for aqueous polyacrylamide. The dependence of elution volume on ionic strength has been used to increase resolution in low molar mass charged polymra and it was noted that non ionic species were unaffected by ionic strength. Water soluble polymers have also been studied by Barth et aL ... 

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