Sampling efficiency

To provide sufficient time for the droplet evolution, one can increase the distance between the ES capillary and the sampling orifice or sampling capillary. However, this reduces greatly the sampling efficiency since the charged droplet density and... 

Based on this background new sampling and analytical methods have been tested in northern Finland to seek new applications for exploration by using surficial till as a sample material with emphasis on decreasing analytical costs and increasing sample efficiency. This study was carried out as a part of ongoing Au, Ni and PGE exploration project of the Geological Survey of Finland. 

In addition to these chemical artifacts, physical artifacts can also occur. For example, the problems of particle bounce (e.g., see Wedding et al., 1986) and reentrainment in impactors were discussed earlier. In addition, air turbulence is known to have a significant effect on the overall sampling efficiency of particle inlets (e.g., Wiener et al., 1988 Francois et al., 1995). 

Wiener, R. W K. Okazaki, and K. Willeke, Influence of Turbulence on Aerosol Sampling Efficiency, Atmos. Environ., 22, 917-928 (1988). 

In order to test the validity of the VELUT model it was used to generate predicted isokinetic values of VE differential sampling efficiency for values of MMAD and GSD corresponding to experimental values reported in the literature. A comparison of the experimental data obtained by Carson and Lynch (10) using mono-disperse aerosols of dioctylphthalate, with the predictions of VELUT for the same conditions is given in Table I. This limited data is in excellent agreement with the predictions of VELUT. 

Comparison of Experimental and Theoretical Values of Isokinetic Sampling Efficiency... 

The model has been used to predict the sampling efficiency of the VE for a wide range of MMAD and GSD values typical of what might be encountered in cotton textile processing. These parameter values are for the actual size distribution of particles in the sampled air, and not for those collected on the membrane filter. These results are summarized in Table II. A remarkable feature of this model is that it predicts that the VE will collect significant amounts of particles with aerodynamic diameters greater than 30 pm. 

Absolute Values of Isokinetic Sampling Efficiency for Various Cotton Dust Distributions... 

The sampler should collect the sample efficiently and have adequate capacity. 

Another important issue that arises in the PDS method, as well as some other standardization methods, is the selection of the samples to use for standardization. It is critical that the standardization samples efficiently convey the magnitude and nature of instrument-to-instrument variability artifacts that are expected to be present in the analyzers while they are operating in the field. Note that this criterion is different than the criterion used for sample selection for calibration, which is to sufficiently cover the compositions of the process samples that the analyzer is expected to see during its operation. Sample selection strategies for instrument standardization have been given by many.73,77-79... 

Presence of other hydrocarbons may interfere in the test. High humidity can affect sampling efficiency. 

If Ciniet has a value of zero, then equation (6.1) reduces to what is commonly called relative recovery and denoted in the literature as RR. The terms EE and RR are frequently interchanged and sometimes the general word, recovery, is used to describe the sampling efficiency of the microdialysis probe. It is important to note that the equivalence of EE versus RR under certain conditions such as with highly regulated concentrations of neurotransmitters has been debated in the literature 46... 

The value of ( used here corresponds to 10 3 of its value in room temperature aqueous solutions. [80] On the one hand, using such weak friction improves the sampling efficiency in the simulations and does not affect equilibrium structural properties. On the other hand, the dynamical properties that we observe may be different from those probed by SM-FRET techniques, which would not be able to resolve conformational dynamics on such fast time scales. Thus, the relevance of the following analysis of dynamical properties relies on the assumption that increasing the friction will not significantly alter our main conclusions. It is interesting to note in this context that the folding mechanism in similar models has been observed to be relatively insensitive to the value of the friction coefficient. [81]... 

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