BioMed2008-38096 APPLICATION OF SPLIT FLOW DESIGN TECHNIQUE TO SIMPLE MICROCHANNEL GEOMETRIES FOR ENHANCED MIXING

ABSTRACT The ability to control mixing of reagents in MEMS systems is crucial for many biological and chemical analysis applications. However mixing in these microfluidic devices is a challenge because the flows are laminar corresponding to very low Reynolds number. In this paper mixing of such reagents in simple microchannel geometries is investigated computationally. A novel concept of "split flow design" is applied to these simple microchannel configurations. Significant improvement in mixing is seen by employing the split flow design technique

CHARACTERIZING JUNCTION-TO-CASE THERMAL RESISTANCE AND ITS IMPACT ON END-USE APPLICATIONS

ABSTRACT High power packages require a low junction-to-case thermal resistance (Theta jc) to achieve target junction temperatures. Theta jc is a metric used to compare package-to-package relative thermal performance. It is also used in two-resistor models to predict thermal performance under system level conditions. This study shows that the commonly used Theta jc definition does not correctly track package junction temperatures in actual end-use applications nor does it serve as a reliable metric for comparing package-to-package performance. When spreading resistance in the lid is taken into account, the modified Theta jc definition overcomes some of the shortfalls found with the standard Theta jc calculation. Lastly, a simplified thermal interface resistance model is presented as a more accurate alternative to the one resistor Theta jc and the multi-resistor Delphi models