Sampling rate effect

Rate effects may not be chemical kinetic ones. Benson and co-worker [84], in a study of the rate of adsorption of water on lyophilized proteins, comment that the empirical rates of adsorption were very markedly complicated by the fact that the samples were appreciably heated by the heat evolved on adsorption. In fact, it appeared that the actual adsorption rates were very fast and that the time dependence of the adsorbate pressure above the adsorbent was simply due to the time variation of the temperature of the sample as it cooled after the initial heating when adsorbate was first introduced. 

If two irradiations are undertaken in similar neutron spectra to the same total number of atomic displacements and at the same temperature, but at different rates (i.e., over different time intervals), the graphite sample with the shorter exposure time will show more damage (i.e., a flux or rate effect). This is because the net observed damage is a function not only of the total damage produced (dependant on the neutron dose), but also on the extent of annealing of that damage, which is... 

At 951 K, the reaction rate is directly proportional to Ph2o a catalytic effect that is attributed [808] to the role of water as an oxygen carrier. The reaction rate was also influenced by the method of salt preparation but for a given sample the effect of particle size was small. 

Swiss case The following means were found 20.32, 20.43, 20.34, 20.60, 20.35, 20.36, 20.45, 20.40, 20.30, and 20.31. The number of tubes with fill weights below the -5% limit was 4, 1, 0, 0, 4, 1, 3, 3, 3, and 3, for a total of 22, and none below the -12.5% one. Twenty-two tubes out of 500 tested correspond to 4.4%. Since the limit is 5% failures, or 2.5 per 50, fully six out of 10IPC inspection runs at u = 50 each did not comply. At a total batch size of 3000 units, eventually 1 /6 of all packages were tested. Evidently, unless the filling overage is further increased, a sampling rate of well above 10% is necessary to exclude these stochastic effects, and so the 10 inspections were combined into one test of n = 500. 

False-positive results with bDNA have been observed with proficiency testing specimens for HTV-1 in the College of American Pathologists HIV-1 viral load survey and HCV in the viral quality control program administered by the Netherlands Red Cross. The reason for the false-positive results with these proficiency testing specimens is not known but may be sample matrix effects. The extent to which this problem occurs with clinical samples has not been determined. However, both the HIV-1 and HCV bDNA assays were designed to have a false-positive rate of 5%. 

Murphy, R.E., Schure, M.R., Foley, J.P. (1998). Effect of sampling rate on resolution in comprehensive two-dimensional liquid chromatography. Anal. Chem. 70, 1585-1594. 

Petty et al. [293] used flow injection sample processing with fluorescence detection for the determination of total primary amines in sea water. The effects of carrier stream flow rate and dispersion tube length on sensitivity and sampling rates were studied. Relative selective responses of several amino acids and other primary amines were determined using two dispersion tube lengths. Linear calibration curves were obtained over the ranges 0-10 6 M and... 

The effect of DP-2) is to produce a virtual pulse whose length is the width of the central lobe. Of course, this is never completely perfect since it does have side-lobes, but waveforms have been described for which the performance in this respect is excellent. DP-3) means that the Doppler frequency shift is being sampled at a discrete set of time points. If the sampling rate is faster than the Nyquist of the Doppler frequency shift, then the Doppler can be unambiguously extracted. 

Fig. 14.10. GC/MS chromatogram showing effect of slow sampling rate. Note the peak asymmetry and the non-smooth appearance, especially of the second peak.

A report (37) on the effect of different types of radiation on the elongatlon-at-break of certain commercial cable Insulating materials pointed to several aspects requiring fundamental Investigations on well-characterised materials under defined conditions. It showed the Importance of antl-oxldant stabilisers, particularly In relation to long term ageing. It was concluded that the differences observed could be attributed to dose rate effects rather than to the types of radiation studied. The Irradiated samples were standard dumb hell shaped tensile samples. 

Sampling rates at different temperatures have been determined by Huckins et al. (1999) for PAHs at 10,18, and 26 °C, by Rantalainen et al. (2000) for PCDDs, PCDFs, and non-ortho chlorine substituted PCBs at 11 and 19 °C, and by Booij et al. (2003a) for chlorobenzenes, PCBs, and PAHs at 2,13 and 30 °C. The effect of temperature on the sampling rates can be quantified in terms of activation energies (A a) for mass transfer, as modeled by the Arrhenius equation... 

A general conclusion that can be drawn from Figure 3.6 is that sampling rates of compounds with log values between 6 and 7 are in the range 2 to 12 L d at flow velocities below 10 cm s, with a geometric mean of 4.2 L d These data underscore the importance of using PRCs for a site- and SPMD-speciflc assessment of the effects of exposure conditions. 

The reference sampling rate (/ s,ref) as well as the exposure-specific effect jSj are divided out. For practical applications, it therefore suffices to know how the compound-specific effect depends on the properties of the analytes. Observing that the experimental sampling rates have a similar dependence on log ATow, but show a varying offset for the different studies, the log-transformed sampling rates observed in 19 calibration experiments in 9 studies were fitted as a third order polynomial in log Kq -... 

Figure 3.7 Compound-specific effect (a) on the sampling rate as a function of log Kow for PCBs— open squares Meadows et al. (1998) PAHs—filled circles Huckins et al. (1999), open triangles Luellen and Shea (2002), filled squares Huckins et al. (2004) HCHs/chlorobenzenes—open diamonds Vrana and Schuurmann (2002) chlorobenzenes/PAHs/ PCBs—filled triangles Booij et al. (2003a) PCDDs/PCDFs/PCBs—asterisks Rantalainen et al. (2000) and pesticides—filled diamonds Sabaliunas and Sodergren (1997), crosses Huckins et al. (2002b).

No large variation in sampling rates is observed among the different studies, despite differences in exposure conditions, such as wind speeds, temperature, and SPMD mounting layout. It should be noted, however, that the effect of temperature is partially accounted for by our use of temperature-corrected log A oa values. An example of the application of Eq. 3.68 for calculating atmospheric concentrations is given in Box 3.3. 

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