The effect of drying corn, rice and wheat seed in two stages was studied, using germinability as a measure of quality. For the first stage, fluidised bed dryer (FBD) and spouted bed dryer (SBD) were used to dry seed from 20-25%wb to 18%wb while in-store dryer (ISO) was used in the second stage for drying from 18%wb to below 14%wb. The drying air temperature range of 40-80??C was studied for the first stage while 18-30??C and relative humidity 60-70% were for the second stage. It was found that dryer type, drying temperature, initial moisture content of seeds and drying time had significant effects on the seed germination. From the result, the drying air temperature of 40??C was safe for corn and rice in FBD while 60??C was acceptable for wheat. In SBD, the 40??C was the maximum drying temperature for rice and wheat without quality deterioration. Meanwhile the second stage drying in an ISD under all specified conditions was safe. In this work, the thin-layer drying models were developed. The results showed that the modified Page's model and modified two-compartment model were the best-fitted models with the root mean square (RMS) of the differences between the predicted moisture ratio and the measured values below 0.03. Besides, the existing ISD simulation program provided the RMS of 0.3, 1.1, and 0.9%wb for corn, rice and wheat respectively. The germination models for FBD and SBD were also developed. As a result, the modified Giner's models 1&2 were the best-fitted models for FBD with the RMS of the differences between predicted and measured germination percentages of 7.9, 4.2 and 3.4% for corn, rice and wheat while the modified Giner's models 2&3 were for SBD with the RMS of 5.5 and 6.1% for rice and wheat respectively. The comparison between FBD and SBD revealed that FBD had faster drying rate while SBD consumed less energy. Ultimately, the energy cost analysis showed that single-stage drying in a fixed bed dryer using ambient condition consumed less energy than two-stage drying using a FBD and ISD but lower energy cost must be weighed against the faster drying rate, flexibility, portable design, and product uniformity of FBD.

The effect of drying corn, rice and wheat seed in two stages was studied, using germinability as a measure of quality. For the first stage, fluidised bed dryer (FBD) and spouted bed dryer (SBD) were used to dry seed from 20-25%wb to 18%wb while in-store dryer (ISO) was used in the second stage for drying from 18%wb to below 14%wb. The drying air temperature range of 40-80??C was studied for the first stage while 18-30??C and relative humidity 60-70% were for the second stage. It was found that dryer type, drying temperature, initial moisture content of seeds and drying time had significant effects on the seed germination. From the result, the drying air temperature of 40??C was safe for corn and rice in FBD while 60??C was acceptable for wheat. In SBD, the 40??C was the maximum drying temperature for rice and wheat without quality deterioration. Meanwhile the second stage drying in an ISD under all specified conditions was safe. In this work, the thin-layer drying models were developed. The results showed that the modified Page's model and modified two-compartment model were the best-fitted models with the root mean square (RMS) of the differences between the predicted moisture ratio and the measured values below 0.03. Besides, the existing ISD simulation program provided the RMS of 0.3, 1.1, and 0.9%wb for corn, rice and wheat respectively. The germination models for FBD and SBD were also developed. As a result, the modified Giner's models 1&2 were the best-fitted models for FBD with the RMS of the differences between predicted and measured germination percentages of 7.9, 4.2 and 3.4% for corn, rice and wheat while the modified Giner's models 2&3 were for SBD with the RMS of 5.5 and 6.1% for rice and wheat respectively. The comparison between FBD and SBD revealed that FBD had faster drying rate while SBD consumed less energy. Ultimately, the energy cost analysis showed that single-stage drying in a fixed bed dryer using ambient condition consumed less energy than two-stage drying using a FBD and ISD but lower energy cost must be weighed against the faster drying rate, flexibility, portable design, and product uniformity of FBD.

Drying is one of the most critical process steps in converting trees to a marketable material for use in high value wood products. The primary reasons for drying wood are to prevent biological deterioration and to improve mechanical strength and dimensional stability. The purpose of this research study was to develop an approach to the control of drying red oak lumber that monitors acoustic emission as the basis for setting environmental conditions throughout the drying process. Northern red oak (Quercus sp.) was chosen for this study because it is one of the more difficult woods grown in the United States to dry without inducing defects. This study was limited to end drying of short lengths of full sized red oak lumber. / Ph. D.

A multistage production system consists of a number of production stages that are interrelated, that is the output from one stage forms input to the next stage. There are constraints associated with each stage as well as constraints imposed by the overall system. Besides, there are multiple objectives that need to be satisfied, and in numerous cases, these objectives conflict with each other. What is required is an efficient technique to allocate and schedule resources so as to provide a balance between the conflicting objectives within the system constraints. This study is concerned with the problem of scheduling multistage production systems in food processing industry. The system and products have complex structure and relationships. This makes the system difficult to be solved analytically. Therefore, the problem is solved by developing a heuristic algorithm that considers most of the constraints. The output generated by the algorithm includes a production schedule which specifies the starting and completion times of the products in each stage and the machines where the products are to be processed. In addition, a summary of system performances including throughput times, resources' utilizations, and tardy products is reported. / Graduation date: 1992