The straw sample was surrounded by polystyrene having twice the insulating value, however the heat continued to flow from the insulation up to the cold plate as well as from the heat source out to the insulation giving very low heat flux measurements in the center of the straw sample. The radiant heater panel had slight fluctuations across the face. This is a conducting, resistive material with positive power lengthwise on the ends and negative in the center. Aluminum foil was wrapped around the flat heating material to increase the consistent heat distribution at the heating source. The placement of thermal sensors was difficult.
Straw is a nonhomogeneous material.
To get the best measurements a temperature sensing probe placement should be exact. The area surrounding the thermocouple needed to be the same density of material as the total bale. A placement of sensor in between, or on the surface of the bales was not an accurate representation of the temperature in the bale. Bale dimension measurements are difficult to within plus or minus one half an inch. The solution was to produce a probe which would not effect the measurements but allow for exact placement.