* Cryogenic refrigeration systems including mixed gas JT systems, reverse-Brayton systems , pulse-tubes, and hybrid cryocoolers
* Thermal-fluid problems in semiconductor manufacturing including immersion lithography, EUV lithography, and nanoimprint
* Vortex tube theory and application
* Refrigeration technology
* Gas bearing supported turbomachinery

• DOD, Navy, 2008-2012, Fundamental Challenges for Low Temperature Pulse Tubes
• DOE, 2010-2013, ARRA Optimization of Regenerators for AMRR Systems
• Strategic polymer Sciences, 2010-2012, Development of Electrocaloric Cooling Systems

• 7,789,371 - Low-power piezoelectric micro-machined valve, granted Sept 2010.

• "Experimental evaluation of an adaptive Joule-Thomson cooling system including silicon-microfabricated heat exchanger and microvalve components"

Zhu WB, Park JM, White MJ et al., Journal of Vacuum Science & Technology A 29 (2): Mar-Apr 2011. This article reports the evaluation of a Joule-Thomson (JT) cooling system that combines two custom micromachined components-a Si/glass-stack recuperative heat exchanger and a piezoelectrically actuated expansion microvalve.

• "An Experimentally Validated Numerical Modeling Technique for Perforated Plate Heat Exchangers"

White MJ, Nellis GF, Klein SA, et al., Journal of Heat Transfer 132 (11): 111801 Nov 2010.  This paper presents a numerical model of a perforated plate heat exchanger that accounts for axial conduction, external parasitic heat loads, variable fluid and material properties, and conduction to and from the ends of the heat exchanger.

• "A Si/glass bulk-micromachined cryogenic heat exchanger for high heat loads: fabrication, test and application results"

Zhu WB, White MJ, Nellis GF, et al., Journal of Microelectromechanical Systems 19 (1): 38-47 Feb 2010. This paper reports on amicromachined Si/glass stack recuperative heat exchanger with in situ temperature sensors.

• "A microvalve with integrated sensors and customizable normal state for low-temperature operation"

Park JM, Evans AT, Rasmussen K, et al., Journal of Microelectromechanical systems 18 (4): 868-877 Aug 2009. This paper reports on design, fabrication, and testing of a piezoelectrically actuated microvalve with integrated sensors for flow modulation at low temperatures. One envisioned application is to control the flow of a cryogen for distributed cooling with a high degree of temperature stability and a small thermal gradient.

• Computational Mechanics Center
• Solar Energy Laboratory