Quality factor (Q) is an important property of micro- and nano-electromechanical (MEM/NEM) resonators that underlie timing references, frequency sources, atomic force microscopes, gyroscopes, and mass sensors. Various methods have been utilized to tune the effective quality factor of MEM/NEM resonators, including external proportional feedback control, optical pumping, mechanical pumping, thermal-piezoresistive pumping, and parametric pumping. This work reviews these mechanisms and compares the effective Q tuning using a position-proportional and a velocity-proportional force expression. We further clarify the relationship between the mechanical Q, the effective Q, and the thermomechanical noise of a resonator. We finally show that parametric pumping and thermal-piezoresistive pumping enhance the effective Q of a micromechanical resonator by experimentally studying the thermomechanical noise spectrum of a device subjected to both techniques.

A realistic process simulation model for heat transfer and compaction along the bleeder-composite assembly was developed. Two case studies were presented with this model in which one took advantage of variable resin properties while the other used constant values. The predicted results were then experimentally validated with 228-ply and 380-ply AS4/3501-6 graphite/epoxy laminates cured under onedimensional resin flow condition. The model-experiment correlation was quite good for the 228-ply laminate, although results with variable resin properties predicted better through-the-thickness temperature distribution than with constant resin properties. The model also predicted faster compaction rate because the compressibility model appeared to predict higher fiber volume fraction for given effective stress. As for the 380-ply laminate, notable deviations were observed for both the temperature and compaction predictions. The discrepancies appeared to have manifested from inaccurate resin property and compressibility models.

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