Processing fundamentals trade-offs

Energy consumption in the beer still increases as its distillate composition gets closer to the azeotrope. On the other hand, energy consumption in the azeotropic-recovery column section of the process decreases as the feed to this section becomes richer in ethanol. It appears that this fundamental trade-off has not been studied in the literature. 

Fuel cell pressurization is typical of many optimization issues, in that there are many interrelated factors that can complicate the question of whether to pressurize the fuel cell. Pressurization improves process performance at the cost of providing the pressurization. Fundamentally, the question of pressurization is a trade-off between the improved performance (and/or reduced cell area) and the reduced piping volume, insulation, and heat loss compared to the increased parasitic load and capital cost of the compressor and pressure-rated equipment. However, other factors can further complicate the issue. To address this issue in more detail, pressurization for an MCFC system will be examined. 

Another approach to matrix application is to robotically deposit small (pL to nL) droplets of matrix on discrete areas of the sample surface. When the droplets are deposited as arrays over the entire tissue surface, mass spectra can be acquired at each matrix spot and reconstructed into an image. In this case, potential analyte delocalization is limited to the area under the matrix spot, typically -100-250 pm with commercially available spotters (e.g., Portrait 630 by Labcyte [23], ChIP by Shimadzu, TM iD by LEAP Technologies). This approach is fundamentally a trade-off between spatial integrity and resolution, because what limits resolution in most cases is the diameter of the laser beam, which is typically much smaller than the diameter of the matrix spot (on the order of 30-50 pm). Samples prepared by spray-coating, either manually or robotically, may be imaged at the diameter of the laser beam, but may not have maintained analyte localization throughout the spray process. 

Speed-accuracy trade-off A fundamental limit of human information-processing systems at any level of abstraction that is most likely due to a more basic limit in channel capacity that is, channel capacity can be used to achieve more accuracy at the expense of speed or to achieve more speed at the expense of accuracy. 

To effectively differentiate solvents in terms of the benefit that one offers over another, or the trade-off the chromatographer faces in choosing one solvent versus another, three fundamental factors need to be considered (1) physical properties of the solvent, (2) the chemical properties of the solvent (especially with respect to system compatibility and safety aspects), and (3) the effects these properties have on the chromatographic process (i.e., system operation, chromatographic separation, detection limits, and analytical reproducibility). This chapter deals with the chemical and physical properties of HPLC solvent groups as well as important features, concerns, and limitations of individual solvents. 

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