Wagner ground

The AC impedance technique coupled to the complex plane method of analysis is a powerful tool to determine a variety of electrochemical parameters. To make the measurements, instrumentation is somewhat more complex than with other techniques. It requires a Wheatstone bridge arrangement with series capacitance and resistance in the comparison arm, a tuned amplifier/detector, and an oscillator with an isolation transformer. A Wagner ground is required to maintain bridge sensitivity, and a suitably large inductance should be incorporated in the electrode polarization circuit to prevent interference from the low impedance of this ancillary circuitry. Sophisticated measurement instruments or frequency response analyzers with frequency sweep and computer interface are currently available such as the Solartron frequency response analyzers. Data obtained can be analyzed or fitted into proper equivalent circuit using appropriate software. 

Using this equation, Wagner and Spoerke assumed that ft, = ftA + K + kK = 1 jr, that is, the triplet lifetime is determined solely by the triplet reaction. In other words, deactivation of the triplet ketone by internal conversion back to the ground state was assumed to be unimportant. The expression then becomes... 

Wagner, R. B., Hampton, D. R., and Howell, J. A., 1989, A New Tool to Determine the Actual Thickness of Free Product in a Shallow Aquifer In Proceedings of the National Water Well Association of Ground Water Scientists and Engineers and the American Petroleum Institute Conference on Petroleum Hydrocarbons and Organic Chemicals in Ground Water Prevention, Detection and Restoration, November, pp. 45-59. 

P.. Wagner, in P. de Mayo (ed.). Rearrangements in Ground and fxc/ted States, vol. 3, Academic Press (1980). The photorearrangements of a simple carbonyl compounds that occur by way ol biradicals are the subject of this account, including reactions that involve intramolecular hydrogen abstraction. 

Wagner, P.J. in "Molecular Rearrangements in the Ground and Excited States" de Mayo, P. Ed. Wiley-Interscience, New York, 1980 Chapter 20, pp. 381-444. 

Barlow, P. M., Wagner, B. J. and Belitz, K. (1996). Pumping strategies for management ofa shallow water table The value of the simulation—optimization approach. Ground Water, 34(2), 305-317. 

S. Murcott, Appropriate remediation technologies for arsenic-contaminated wells in Bangladesh, in Proc. Int. Conf. Arsenic in Ground Water in Bangladesh Sources and Remedies, Wagner College, Staten Island, New York, February 27-28, 1999. 

Wagner, P.J., Hasegawa, T., Zhou, B., and Ward, D.L. (1991) Diverse photochemistry of sterically congested a-arylacetophenones ground-state conformational control of reactivity. Journal of the American Chemical Society, 113, 9640-9654. 

Pundt L, Van Roozendael M., Wagner T., Richter A., Chipperfield M., Burrows J. P., Fayt C., Hendrick F., Pfeilsticker K., Platt U., and Pommereau J.-P. (2000) Simultaneous UV-vis Measurements of BrO form Balloon, SateUite and Ground implications for tropospheric BrO. In Proc. 5th European Symp. on Polar Stratospheric Ozone 1999, Air Poll. Res. Report 73, EUR 19340 (eds. N. R. P. Harris, M. Guirlet, and G. T. Amanatidis). European Commission, Brussels, Belgium, pp. 316-319. 

The values of the primary quantum yields, found in the photolysis of ketones with y-H atoms, were explained by Brunet and Noyes on the basis of steric effects that diminish the probability of the formation of the cyclic complex. Following the original suggestion of Whiteway and Masson, Martin and Pitts proposed the internal conversion of the cyclic structure to be responsible for the low primary quantum yields observed in the photolysis of ketones capable of forming such a structure. In contrast to other interpretations. Wagner and Hammond explained the low quantum yields by an elementary chemical process, suggesting that the y-H atom transfer is reversible, i.e. that the biradical, after vibrational relaxation, may convert back into the ground state ketone molecule, viz. 

Wagner, P.J. (1980), Photorearrangements via Biradicals of Simple Carbonyl Compounds, in Rearrangements in Ground and Excited States, 3 de Mayo, P., Ed. Academic Press New York. 

---