| Author: | Reid Bailey |
| Title: | Input-Output Modeling of Material Flows in Industry |
| Institution: | Georgia Tech, G.W. Woodruff School of Mechanical Engineering |
| Date: | July 2000 |
| Advisor: | Drs. Janet K. Allen and Bert Bras |
| Key Words: | material flow analysis, material flow metrics, industrial ecology, input-output modeling, recycling |
| How to Obtain: | on the web at http://www.srl.gatech.edu/people/reid/rb_phd.html; interlibrary loan form Georgia tech, UMI dissertation service, directly from the author or advisors. |
| Abstract: | Material flows represent one of the strongest, most inextricable links
between natural and industrial systems. With increasing environmental
problems, understanding material flows in industrial systems 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 and facilitating the synthesis of
new systems. The core capabilities of flow analysis include the characterization
of system behavior with metrics and the tracing of material flows through
systems with environs.
In this dissertation, several directions are taken to examine the application of flow analysis to material flows in industrial systems. First, through grounding flow analysis in causal theory, the concept of causal closure is introduced to mathematically model the interconnectedness of material flows in industry. As the cycling of materials in industry increases (through recycling, reuse, etc.), industrial systems are shown to become more causally closed, thereby increasing the difficulty to effectively understand the system without tools such as flow analysis. The flow analysis metrics, including measures of material cycling, are connected to controllable aspects of flow systems and to environmental objectives, thereby facilitating the synthesis of changes to a system using flow analysis results. Beyond metrics, flow environs allow a modeler to trace material flows through a system. 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 systems, several common material flow archetypes are identified. Examples of these archetypes include material flow structures for reuse and recycling. 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 is 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 a single product from a single company. Through the case studies, the capabilities and limitations of flow analysis are identified, assessed and extended. |