Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Chemical and Biological Engineering


Many investigators have attempted to gain insight into the thermodynamics and energetics of growth by correlating various parameters with metabolic activity. Interpretation of these expressions was often difficult. Frequently terms without physical meaning appear. The purpose of this research project is to develop mathematical relationships that adequately describe embryonic energetics, both within the growing organism and in the surrounding microenvironment, using fundamental chemical principles;In this work two growth models are proposed: one is formulated from equilibrium thermodynamics and kinetics while the other utilizes nonequilibrium thermodynamic principles. The models are based on a small set of basic metabolic reactions that are shown to characterize growing biological systems. The role of the adenosine nucleotides in coordinating and controlling metabolism is included. Theoretical expressions for parameters such as oxygen consumption, heat production, dry tissue growth rate and relative growth efficiency are derived and their utility in assessing metabolic activity is demonstrated;The interactions between embryonic energetics and the surrounding microenvironment is demonstrated with a specific example. In particular, the heat and mass exchange of eggs incubating in a clutch is considered. Orthogonal collocation on finite elements is used to determine temperature and egg mass profiles in the clutch. The buffering capability of the clutch against thermal oscillations in the surrounding medium is also examined.



Digital Repository @ Iowa State University,

Copyright Owner

Scott D. Pearson



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134 pages