NASA Scientific and Technical Aerospace Reports

activities and both funded and non-funded projects that enhance the educational mission of the Department of Integrated
Science and Technology. During the term of this support fifteen students benefited directly, several of these students
participated in an international conference and were published in conference proceedings. The IDTTL was also successful in
proposals to NASA for further support and to NSF for new instrumentation and imaging equipment.
Author
Carbon Monoxide; Imaging Techniques; Infrared Radiation; Atmospheric Chemistry; High Temperature Tests; Radiation
Measuring Instruments
20040111964 NASA Langley Research Center, Hampton, VA, USA
Corrosion Detection in Airframes Using a New Flux-Focusing Eddy Current Probe
Fulton, James P.; Wincheski, Buzz; Nath, Shridhar; Namkung, Min; [1994]; 3 pp.; In English; No Copyright; Avail: CASI;
A01, Hardcopy
A new flux-focusing eddy current probe was recently developed at NASA Langley Research Center. The new probe is
similar in design to a reflection type eddy current probe, but is unique in that it does not require the use of an impedance bridge
for balancing. The device monitors the RMS output voltage of a pickup coil and, as a result, is easier to operate and interpret
than traditional eddy current instruments. The unique design feature of the probe is a ferromagnetic cylinder, typically 1020
steel, which separates a concentrically positioned drive and pickup coil. The increased permeability of the steel causes the
magnetic flux produced by the drive coil to be focused in a ring around the pickup coil. At high frequencies the eddy currents
induced in both the sample and the cylinder allow little or no flux to link with the pickup coil. This results in a self-nulling
condition which has been shown to be useful for the unambiguous detection of cracks in conducting materials. As the
frequency is lowered the flux produced by the drive coil begins to link with the pickup coil causing an output which, among
other things, is proportional to the thickness of the test specimen. This enables highly accurate measurements of the thickness
of conducting materials and helps to facilitate the monitoring of thickness variations in a conducting structure such as an
aircraft fuselage. Under ideal laboratory conditions the probe can sense thickness changes on the order of 1% as illustrated.
However, this is highly dependent upon the thickness, and the geometric complexity of the sample being tested and for
practical problems the sensitivity is usually much less. In this presentation we highlight some of the advantages and limitations
in using the probe to inspect aircraft panels for corrosion and other types of material nonuniformities. In particular, we present
preliminary results which illustrate the probes capabilities for detecting first and second layer corrosion in aircraft panels
which may contain air gaps between the layers. Since the probe utilized eddy currents its corrosion detection capabilities are
similar to convectional eddy current techniques, but the new probe is much easier to use.
Derived from text
Airframes; Corrosion; Eddy Currents; Probes; Magnetic Flux
20040111985 Brown Univ., Providence, RI, USA
Remote Sensing Information Applied to Geological Study of Planets
Pieters, Carle M.; January 2004; 3 pp.; In English
Contract(s)/Grant(s): NAG5-10401; No Copyright; Avail: CASI; A01, Hardcopy
The Planetary Geology and Geophysics tasks under this grant have concentrated on the development and testing of tools
for remote compositional analyses for the Moon and other airless bodies (especially asteroids). The grant has supported the
PI and her students. Detailed analyses of space-weathering analogs were undertaken. Lunar research included development
of models for regolith evolution and redistribution of materials across the Moon, with particular emphasis on the interior of
South Pole-Aitken Basin. Lunar compositional analyses identified general rock types using Clementine data and mapped their
distribution globally and locally based on the type of mafic mineralogy present (or lack thereof). Progress in these areas has
been extensively discussed in the literature and in proposals submitted to the PGG program in 2003 and 2004.
Author
Remote Sensing; Geology; Moon; Planetary Geology; Lunar Evolution
20040112036 NASA Langley Research Center, Hampton, VA, USA
A Digital Video Model Deformation System
Burner, A. W.; Snow, W. L.; Goad, W. K.; Childers, B. A.; [1986]; 11 pp.; In English; No Copyright; Avail: CASI; A03,
Hardcopy
The use of slid-state array cameras and a PC controlled image acquisition system to measure model deformation in a wind
tunnel is discussed. This digital system is an improvement to an earlier video model deformation system used at the National
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