Pulsed engineering aspects

Zhang, Q.H., Chang, F.J., Barbosa-Canovas, G.V., and Swanson, B.G. 1995a. Engineering aspects of pulsed electric field pasteurization. Journal of Food Engineering 25 261-291. 

This chapter gives a short introduction to solid state NMR and then presents some recent results where the development of new pulse sequences have brought some insights into various aspects of the characterization of solid state materials. Finally attention will be focused on the information that the technique can provide in the field of crystal engineering, in the detection of polymorphism and in the dynamic processes occurring in the solid state. 

Pulse radiolysis has been employed successfully to resolve mechanisms of action of redox proteins and of electron transfer within their polypeptide matrix. The limitations on the use of this method, set by the requirement for expensive electron accelerators, are more than compensated for by experimental advantages, as illustrated by the results described in this chapter. Future applications to the study of engineered proteins and other model systems would certainly extend our understanding of both of these aspects of redox processes in biological macromolecules. 

Detailed investigation of the reaction mechanism was performed using a TAP reactor (Autoclave Engineers). Both the TAP apparatus and technique have been described in detail by the inventors [7,8], and otdy those aspects most relevant to this study will be included here. The system comprises four main features (i) a valve assembly which permits the introduction of either a very narrow gas pulse or a continuous flow, (ii) a catalytic microreactor, (iii) a high vacuum system, (iv) a quadrupole mass spectrometer. 

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