MICROWAVE MEASUREMENT OF WOOD MOISTURE PROFILE DURING KILN DRYING

MANY OF THE DEFECTS THAT APPEAR IN WOOD DURING DRYING OR DURING MATCHINING ORIGINATE FROM SHRINKAGE DURING DRYING AND FROM ITS ASSOCIATED STRESSES. THE ABILITY TO SENSE SHRINKAGE AND STRESSES MAY ALLOW SUCH DEFECTS TO BE AVOIDED NY CAREFUL CONTROL OF TEMPERATURE, HUMIDITY, AND AIRFLOW CONDITIONS WITHIN THE KILN. THIS COULD ULTIMATELY RESULT IN IMPROVED WOOD QUALITY AND INCREASED LUMBER YIELD BY REDUCING WASTE. MEASUREMENT OF MOISTURE CONTENT PROFILE IS A POTENTIAL METHOD OF GAINING INFORMATION ON SHRINKAGE AND STRESSES. THE PURPOSE OF THIS PROJECT IS TO ANALYZE THE FEASIBILITY OF A SOPHISTICATED WOOD MOISTURE PROFILE MEASUREMENT SYSTEM BASED ON MEASUREMENT OF THE REFLECTION COEFFICIENT OF WOOD AT MICROWAVE FREQUENCIES. DATA WILL BE TAKEN ON WOOD SAMPLES PREPARED TO VARIOUS MOISTURE CONTENT LEVELS WITH A VECTOR NETWORK ANALYZER BASED MEASUREMENT SYSTEM. DATA WILL BE COMPARED TO DATA OBTAINED BY TRADITIONAL METHODS. MEASURED DATA WILL ALSO BE COMPARED TO PREDICTED VALUES OF MODELS OF WOOD WITH VARIOUS MOISTURE CONTENT PROFILES.