Reciprocating Mechanism–Driven Heat Loop (RMDHL) Cooling Technology for Power Electronic Systems

The most significant hindrances to the technological advances in high power electronics (HPE) and digital computational devices (DCD) has always been the issue of effective thermal management. Energy losses during operation cause heat to build up in these components, resulting in temperature rise. Finding effective thermal solutions will become a major constraint for the reduction of cost and time-to-market, two governing factors between success and failure in commercial evolution of technology. Even when high temperatures are not reached, high thermal stresses because of temperature variations are major causes of failure in electronic components mounted on circuit boards. An effective electronic cooling technique, which is based on reciprocating heat pipe, is the so-called reciprocating mechanism–driven heat loop (RMDHL) that has a heat transfer mechanism different from those of traditional heat pipes. Experimental results show that the heat loop worked very effectively and a heat flux as high as 300 W/cm2 in the evaporator section could be handled. In addition to eliminating the cavitation problem associated with traditional two-phase heat loops, the RMDHL also provides superior cooling advantage with respect to temperature uniformity. Considering the other advantages of coolant leakage free and the absence of cavitation problems for aerospace-related applications, the single phase RMDHL could be an alternative of a conventional liquid cooling system (LCS) for electronic cooling applications. This chapter will provide insight into experimental, numerical and analytical study undertaken for RMDHL in connection with high heat and high heat flux thermal management applications and electronic cooling. In addition to clarifying the fundamental physics behind the working mechanism of RMDHLs, a working criterion has also been derived, which could provide a guidance for the design of a reciprocating mechanism–driven heat loop

Effects of Network Connectivity and Diversity Distribution on Human Collective Ideation

Human collectives, e.g., teams and organizations, increasingly require participation of members with diverse backgrounds working in networked social environments. However, little is known about how network structure and the diversity of member backgrounds would affect collective processes. Here we conducted three sets of human-subject experiments which involved 617 participants who collaborated anonymously in a collective ideation task on a custom-made online social network platform. We found that spatially clustered collectives with clustered background distribution tended to explore more diverse ideas than in other conditions, whereas collectives with random background distribution consistently generated ideas with the highest utility. We also found that higher network connectivity may improve individuals' overall experience but may not improve the collective performance regarding idea generation, idea diversity, and final idea quality.Comment: 43 pages, 19 figures, 4 table