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Hand-Held Reflectometer Inspects Infrared Material Properties
The Air Force Research Laboratory Materials and Manufacturing Directorate, Nondestructive Evaluation Branch, in collaboration with Surface Optics Corporation and Boeing Defense and Space Group, have developed an accurate nondestructive evaluation method to inspect special coatings used on modern Air Force weapon systems. Their development, a hand held directional reflectometer, is the first of its kind device to fully characterize the infrared reflectance properties of these coatings directly on the aircraft. The Hand Held Directional Reflectometer (HHDR) unit is a major step forward in the ability to make accurate infrared (IR) reflectance measurements on coatings used for modern weapon systems. This lightweight, portable, multi-functional instrument is capable of measuring IR coatings at angles from normal incidence to five degrees off grazing, in either the mid- or long-waveband. The resulting data will assure engineers and maintenance personnel that coating applications, repair and restorations have been performed correctly. The Air Force can save valuable time and money while increasing reliability and confidence in coating effectiveness. Air Force weapon systems require protection against IR based detection and tracking systems. Air-to-air and surface-to-air missiles in the 3m to mid-band range are most commonly used while IR threats in the 8m to 12m long-wave band are emerging. Special IR topcoats help reduce the missile threat effectiveness for modern air vehicles. IR reflectance properties are measured to determine the IR coating effectiveness. The current state-of-the-art technology requires that special coupon samples be prepared and tested using large and expensive laboratory equipment. This specialized process requires highly trained technical personnel, takes many hours to perform single measurements, and the lab coupons may not represent the state of the coatings applied to aircraft. With the broadening use of IR topcoats to modern weapon systems, there is a need to develop capabilities for in situ measurements of the IR properties of the coatings. Scientists at the Materials and Manufacturing Directorate, Nondestructive Evaluation Branch, Wright-Patterson AFB Ohio, contracted with Boeing Defense and Space Group, Seattle, Wash., and Surface Optics Corporation, San Diego, Calif., to develop a portable, hand-held instrument to fully characterize the IR reflectance properties of aircraft coatings. The result is a prototype model of a hand-held directional reflectometer (HHDR). This instrument uses angular imaging and a room temperature microbolometer focal plane array to rapidly determine the angular distribution of IR energy reflected from a two millimeter square specimen surface. Images can quickly be captured from angles ranging from normal incidence to approximately five degrees off grazing. Measurements of material properties near-grazing angles are vital since that is what is seen. The device can operate in either the mid-waveband or long-waveband. The HHDR is powered and controlled by a laptop computer which captures and archives the measurement data. The system is designed for rapid data collection and evaluation, rugged field operation, and easy portability. The HHDR unit offers several advantages. First, IR engineers can fully characterize in near real-time the IR material properties directly on the aircraft. Second, maintenance personnel can check and compare the condition of coatings in the field, before and after repair and restoration. Routine inspection and monitoring as well as long-term coating degradation can rapidly be measured and quantified. Third, coating integrity and effectiveness can be measured on the aircraft while it is still in the production environment, a tangible help to production and quality assurance personnel. The performance to date of the prototype indicates its outstanding usefulness for maintaining IR coatings in the field. Research and development of the HHDR is advancing the state-of-the-art in NDE for IR material characterization and development work will continue to improve its performance. Related Links SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express 
Lasers Coax Large Molecules To Change Their Shape
West Lafayette - May 23, 2002Lasers are used to carry out functions ranging from reading a bar code label at the grocery store to shooting down enemy missiles in space. Now, chemists at Purdue University are using lasers to coax individual molecules to change their shape, a step that may someday enable scientists to direct molecules to perform specific functions.
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