Herbst

Herbst E 1987 Gas phase chemical processes in molecular clouds Interstellar Prooesses ed D J Hollenbach and H A Tronson (Dordrecht Reidel) pp 611-29... 

Herbst E 1995 Chemistry in the interstellar medium Ann. Rev. Rhys. Chem. 46 27-53... 

J. A. Herbst, ed.. Control 84—Minerals f Metallurgical Processing AIMME, New York, 1984. 

R. K. Rajamani andj. A. Herbst, eds.. Control 90—Mineral and Metallurgical Processing SME, Litdeton, Colo., 1990. 

W. Herbst and K. Hunger, Industrial Organic Pigments, VCH, Weinhekn, Germany, 1993. 

W. A. Herbst andN. V. Hakala, 7th World Petroleum Congress, Mexico City, Mexico, Apr. 1967. 

Herbst et al. [International J. Mineral Proce.ssing, 22, 273-296 (1988)] describe the software modules in an optimum controller for a grinding circuit. The process model can be an empirical model as some authors have used. A phenomenological model can give more accurate predictions, and can be extrapolated, for example from pilot-to full-scale apphcation, if scale-up rules are known. Normally the model is a variant of the popiilation balance equations given in the previous section. 

Rajamani and Herbst (loc. cit.) compared control of an experimental pilot-mill circuit using feedback and optimal control. Feedback control resulted in oscillatory behavior. Optimal control settled rapidly to the final value, although there was more noise in the results. A more complete model should give even better results. 

Alpha amino acids (and aldehydes) synthesis by reaction of an alpha keto add with another amino acid (Herbst-EngeO or by reaction of a keto acid with ammonia tmdef reducing conditions (Knoop-Oe sterling). 

Ethyl oxalylsuccinate has been prepared by the condensation of ethyl oxalate with ethyl succinate in the presence of sodium ethoxide or of potassium ethoxide. The method described above is somewhat more convenient, and has given a higher yield of a better product, than one based upon sodium ethoxide, submitted by A. E. Martell and R. M. Herbst. 

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