Ph.D. Thesis Defense by Reid Bailey
Friday, July 14, 2000

(Drs. Bert Bras and Janet Allen, co-advisors)

"Input-Output Modeling of Material Flows in Industy"


Material flows represent one of the strongest, most inextricable links between natural and industrial systems.  With increasing environmental problems, understanding industrial systems of material flows has never been more crucial, yet at the same time never more difficult due to their complexity.  To better understand systems of material flows in industry, the validity and usefulness of input-output flow analysis are investigated in this dissertation.  With direct roots in ecology, flow analysis is shown to have solid mathematical and philosophical foundations for modeling material flows in industrial systems.  Flow analysis is composed of a unique, versatile and adaptable array of tools capable of modeling complex industrial systems of material flows.  The core capabilities of flow analysis include the characterization of system behavior with metrics and the tracing of material flows through systems with environs.

Flow analysis metrics, including measures of flow cycling, allow a modeler to make comparisons between different systems.  The relationships between model attributes and flow analysis metrics are examined to provide insight as to why a system behaves in a certain manner.  Beyond metrics, flow environs are shown to allow a modeler to trace material flows from system inflows to outflows.  Environs are useful for in depth analysis of the structure of a material flow system.  To enhance the usefulness of applying flow analysis to industrial material flow systems, several common material flow archetypes (e.g., recycling, reuse) are identified.  Archetypes serve as building blocks for constructing flow models and allow for different material flow strategies to be evaluated easily.  The usefulness of the archetypes, metrics and environs are evaluated in the context of material flows in industrial systems with four case studies.  The case studies range from material flows of an entire nation to flows of carpet from a single company.  Through the case studies, the capabilities and limitations of flow analysis are identified, assessed and extended.