Fischer criterion

Other investigators have also dealt with the 1-D question. Ruthven 78) has used the Fischer criterion in an assessment of applicability of the 1-D model for BOD. McQuivey and Keefer 62) note that about 150 miles may be required in a particular stretch of the lower Mississippi River for 1-D conditions to be met after a dye dump. 

The extraction of water at room temperature as a procedure for the calibration of the Fischer method requires further verification, because the reagent is not specific for water. It would be desirable to compare this calibration procedure with another. In general, agreement in the results of two or more independent calibration procedures might be used as a criterion of the attainment of accuracy. 

Now we can understand why we cannot draw a Fischer projection sideways. If we did, we would be inverting the stereocenter. To draw the enantiomer of a Fischer projection, do not turn the drawing sideways. Instead, you should use the second method we saw for drawing enantiomers (place the mirror on the side of the compound and draw the reflection). Recall that this was the method that we used for drawings where wedges and dashes were implied but not shown. Fischer projections are another example of drawings that fit this criterion ... 

Different estimations of the strength of the January 1993 event (cf. Section 10.4.3) led to the reassessment of the intensity. Instead of the mean salinity, Fischer and Matthaus (1996) used the amount of salt q (in Gt = IO kg), entering the Baltic Sea over both the Darss Sill (DS) and the Drogden Sill (DR), as the criterion for the intensity of MBls. On this basis, they recalculated the intensity of 90 events that took place between 1897 and 1976. The new method permitted the quantitative estimation of the strength of MBls using the total salt transport into the Baltic Sea. 

It is known that the formazan reaction depends upon two conditions. The first is the presence of an aldehydo Schiff base (—CH=N—), a criterion which is fulfilled in aWe%do-phenylhydrazones, but not in fceto-phenylhydrazones or in phenylhydrazones of the cyclic hemiacetal forms of the aldoses. The second condition is the presence of free imino hydrogen in the phenylhydrazone group. If Fischer s open-chain structure is correct, the phenylhydrazone group at Cl satisfies both conditions, and the formazan reaction would be expected to proceed according to the following equation. 

To name the various compounds, Fischer and others laid the foundations of a terminology still in use, based on the terms triose, tetrose, pentose, and hexose. He endorsed Armstrong s proposal to classify sugars into aldoses and ketoses, and proposed the name fructose for levulose because he found that the sign of optical rotation was not a suitable criterion for grouping sugars into families. 

Fischer suggests Eq. (28) as a criterion for estuaries also. In terms of time, the time required for a side discharge to mix completely across the cross section (T mix) is on the order of... 

For a consecutive reaction, such as A B C, Cohen and Fischer" suggested that tme isosbestic points do not occur, which is the criterion often used to differentiate the parallel and consecutive mechanisms. Bunnett presumed that spectral evidence for the formation of intermediate B might be obtained at the isosbestic point between A and C absorbance, if the intermediate B accumulates before converting to C. 

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