Body Ambient Bondgraph Model Using Heat Flux Transducer

Abstract

This collection is a compilation of the three modules created as part of EE5821 - Spring 08 at the University of Minnesota. Each module comprises a stand alone section of an overal project of a biomedical model. ABSTRACT There are numerous occupational and leisure tasks for which the participants are at risk of heat stress related illness. Heat stress illness effects can be either acute, such as heat stroke, heat exhaustion, heat cramps, fainting, and decline of performance; or chronic, such as loss of ability to tolerate heat, hypertension, heart muscle damage, reduced libido and impotence. Existing practices for protection against heat stress are limited to awareness education of antagonistic conditions. Persistent monitoring of individuals is not an existing practice due to a variety of factors, including drawbacks to the sensor devices and lack of quantitative definition of heat stress limits. This project presents a Bondgraph model to illustrate the body-ambient heat exchange and how it would be measured using a heat flux transducer. Individual contributions to body heat are shown as r-elements. A measurement device of a heat flux transducer is shown as a transformer element. The equation layer of the model can be tailored for various operating conditions, using either derived or empirical formulas to describe heat transfer. The model shows the same various components of body ambient heat exchange as are found in most occupation educational literature. Bondgraph figures further demonstrate causality and direction of power flow. Not fully quantified in the literature uncovered in research are how the body thermoregulatory functions begin to break down This data suggest that given a sound understanding of the heat transfer mechanisms operating with the human body during high risk tasks and environments, a heat flux transducer should provide a leading indicator of heat stress illness for any variety of tasks.