Chemical Processing-August 2008 - (Page 14) in process Copper nanorods Figure 2. Photomicrograph shows copper nanorods on copper surface that dramatically increase bubble creation and thus boiling efficiency. Source: Nikhil Koratkar, Rensselaer Polytechnic Institute. sor in the school’s department of mechanical, aerospace and nuclear engineering. Other metals and metalloids like silicon may provide similar results, he adds. Such synergy between the nanoscale and microscale surfaces was unexpected, Koratkar says. His team discovered, though, that the dynamics of bubble generation and release differ fundamentally between a conventional surface and one with the nanorods. Pockets of air trapped within the rods feed nanobubbles into the microscale cavities of the vessel surface to help prevent those cavities from becoming flooded with water, he explains. “We observed a 30-fold increase in active bubble nucleation site density — a fancy term for the number of bubbles created — on the surface treated with copper nanotubes over the nontreated surface.” This spurred to a six-to-ten times greater amount of vapor at the heating surface, he adds. Tests were conducted with 1-in. × 1-in. wafer covered with nanorods via oblique-angle deposition. The nanorods’ height was about 450 nm and the tip-to-tip spacing between them was around 50 nm. While the technique ultimately may lead to better energy efficiency in industrial heat exchangers, Koratkar foresees the most immediate potential for taking care of hot spots on microelectronic circuits. He’s already talking to some chipmakers and hopes to start tests within the next year. He also aims to explore whether a thin hydrophobic layer on the nanorods will provide even greater bubble density and to investigate the effect of rod height, spacing and orientation. Robustness of the rods may need attention, he admits. In the tests after five to 10 cycles, some aging or deterioration occurred. So, he also plans to explore alternatives to create more robust rods. Experience the World of Automation exiderdome U.S. Tour | July 2008 - May 2009 w w w. e x i d e rd o m e . c o m / u s http://www.exiderdome.com/us
Table of Contents Feed for the Digital Edition of Chemical Processing-August 2008 Chemical Processing- August 2008 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor Protect your Plant What’s on Tap for Water? Keep Operations Safe Polystyrene Plant Gains Extra Output and More Process Puzzler Plant InSites Equipment & Services Adlits Product Spotlight/Classifieds Ad Index End Point Chemical Processing-August 2008 Chemical Processing-August 2008 - Chemical Processing- August 2008 (Page Cover1) Chemical Processing-August 2008 - Chemical Processing- August 2008 (Page Cover2) Chemical Processing-August 2008 - Chemical Processing- August 2008 (Page 3) Chemical Processing-August 2008 - Chemical Processing- August 2008 (Page 4) Chemical Processing-August 2008 - Contents (Page 5) Chemical Processing-August 2008 - Contents (Page 6) Chemical Processing-August 2008 - From the Editor (Page 7) Chemical Processing-August 2008 - From the Editor (Page 8) Chemical Processing-August 2008 - ChemicalProcessing.com (Page 9) Chemical Processing-August 2008 - ChemicalProcessing.com (Page 10) Chemical Processing-August 2008 - Field Notes (Page 11) Chemical Processing-August 2008 - Field Notes (Page 12) Chemical Processing-August 2008 - In Process (Page 13) Chemical Processing-August 2008 - In Process (Page 14) Chemical Processing-August 2008 - In Process (Page 15) Chemical Processing-August 2008 - In Process (Page 16) Chemical Processing-August 2008 - Energy Saver (Page 17) Chemical Processing-August 2008 - Energy Saver (Page 18) Chemical Processing-August 2008 - Compliance Advisor (Page 19) Chemical Processing-August 2008 - Protect your Plant (Page 20) Chemical Processing-August 2008 - Protect your Plant (Page 21) Chemical Processing-August 2008 - Protect your Plant (Page 22) Chemical Processing-August 2008 - Protect your Plant (Page 23) Chemical Processing-August 2008 - Protect your Plant (Page 24) Chemical Processing-August 2008 - Protect your Plant (Page 25) Chemical Processing-August 2008 - Protect your Plant (Page 26) Chemical Processing-August 2008 - What’s on Tap for Water? (Page 27) Chemical Processing-August 2008 - What’s on Tap for Water? (Page 28) Chemical Processing-August 2008 - What’s on Tap for Water? (Page 29) Chemical Processing-August 2008 - What’s on Tap for Water? (Page 30) Chemical Processing-August 2008 - What’s on Tap for Water? (Page 31) Chemical Processing-August 2008 - Keep Operations Safe (Page 32) Chemical Processing-August 2008 - Keep Operations Safe (Page 33) Chemical Processing-August 2008 - Keep Operations Safe (Page 34) Chemical Processing-August 2008 - Keep Operations Safe (Page 35) Chemical Processing-August 2008 - Keep Operations Safe (Page 36) Chemical Processing-August 2008 - Keep Operations Safe (Page 37) Chemical Processing-August 2008 - Keep Operations Safe (Page 38) Chemical Processing-August 2008 - Polystyrene Plant Gains Extra Output and More (Page 39) Chemical Processing-August 2008 - Polystyrene Plant Gains Extra Output and More (Page 40) Chemical Processing-August 2008 - Process Puzzler (Page 41) Chemical Processing-August 2008 - Process Puzzler (Page 42) Chemical Processing-August 2008 - Plant InSites (Page 43) Chemical Processing-August 2008 - Equipment & Services (Page 44) Chemical Processing-August 2008 - Adlits (Page 45) Chemical Processing-August 2008 - Product Spotlight/Classifieds (Page 46) Chemical Processing-August 2008 - Product Spotlight/Classifieds (Page 47) Chemical Processing-August 2008 - Product Spotlight/Classifieds (Page 48) Chemical Processing-August 2008 - Ad Index (Page 49) Chemical Processing-August 2008 - End Point (Page 50) Chemical Processing-August 2008 - End Point (Page Cover3) Chemical Processing-August 2008 - End Point (Page Cover4)
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