Defence industry supplier Ultra Electronic Holdings has bought Adaptive Materials, a US designer and manufacturer of portable power solutions.The company has been acquired from its founders, Dr. Aaron and Michelle Crumm, for an initial cash consideration of $23.0m. A further sum of up to $5.0m will be payable if certain performance-based measures are achieved by 31 December 2013.Adaptive Materials has developed Solid Oxide Fuel Cells that run on propane and provide more power in less space than competing technologies. Its products are suitable for niche applications where the power requirements are too small for conventional generators and too large for batteries.Adaptive Materials has a significant intellectual property portfolio and is now preparing to enter volume production. It employs around 50 staff, including 15 engineers, operating from a facility in Ann Arbor, Michigan, USA.Adaptive Materials will continue to operate from its existing facilities as a bolt-on acquisition, reporting to Phil Evans, managing director of Ultra's Aircraft & Vehicle Systems division.