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819 Matching Results

Start Over Year 1997 Day 5th

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Results: 1 - 24 of 819 next

(open access)

Determining thermal diffusivity and defect attributes in ceramic matrix composites by infrared imaging.

Ceramic matrix composites are being developed for numerous high temperature applications, including rotors and combustors for advanced turbine engines, heat exchanger and hot-gas filters for coal gasification plants. Among the materials of interest are silicon-carbide-fiber-reinforced-silicon-carbide (SiC{sub (f)}/SiC), silicon-carbide-fiber-reinforced-silicon-nitride (SiC{sub (f)}/Si{sub 3}N{sub 4}), aluminum-oxide-reinforced-alumina (Al{sub 2}O{sub 3(f)}/Al{sub 2}O{sub 3}), etc. In the manufacturing of these ceramic composites, the conditions of the fiber/matrix interface are critical to the mechanical and thermal behavior of the component. Defects such as delaminations and non-uniform porosity can directly effect the performance. A nondestructive evaluation (NDE) method, developed at Argonne National Laboratory has proved beneficial in analyzing as-processed conditions and defect detection created during manufacturing. This NDE method uses infrared thermal imaging for fill-field quantitative measurement of the distribution of thermal diffusivity in large components. Intensity transform algorithms have been used for contrast enhancement of the output image. Nonuniformity correction and automatic gain control are used to dynamically optimize video contrast and brightness, providing additional resolution in the acquired images. Digital filtering, interpolation, and least-squares-estimation techniques have been incorporated for noise reduction and data acquisition. The Argonne NDE system has been utilized to determine thermal shock damage, density variations, and variations in fiber coating in a full …

Date: December 5, 1997

Creator: Ahuja, S.; Ellingson, W. A.; Koehl, E. R. & Stuckey, J.

Object Type: Article

System: The UNT Digital Library

(open access)

The Boerne Star (Boerne, Tex.), Vol. 93, No. 62, Ed. 1 Tuesday, August 5, 1997

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.

Date: August 5, 1997

Creator: Aldridge, Leon

Object Type: Newspaper

System: The Portal to Texas History

(open access)

The Boerne Star (Boerne, Tex.), Vol. 93, No. 71, Ed. 1 Friday, September 5, 1997

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.

Date: September 5, 1997

Creator: Aldridge, Leon

Object Type: Newspaper

System: The Portal to Texas History

(open access)

The Boerne Star (Boerne, Tex.), Vol. 93, No. 97, Ed. 1 Friday, December 5, 1997

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.

Date: December 5, 1997

Creator: Aldridge, Leon

Object Type: Newspaper

System: The Portal to Texas History

(open access)

Radiation damage of a glass-bonded zeolite waste form using ion irradiation.

Glass-bonded zeolite is being considered as a candidate ceramic waste form for storing radioactive isotopes separated from spent nuclear fuel in the electrorefining process. To determine the stability of glass-bonded zeolite under irradiation, transmission electron microscope samples were irradiated using high energy helium, lead, and krypton. The major crystalline phase of the waste form, which retains alkaline and alkaline earth fission products, loses its long range order under both helium and krypton irradiation. The dose at which the long range crystalline structure is lost is about 0.4 dpa for helium and 0.1 dpa for krypton. Because the damage from lead is localized in such a small region of the sample, damage could not be recognized even at a peak damage of 50 dpa. Because the crystalline phase loses its long range structure due to irradiation, the effect on retention capacity needs to be further evaluated.

Date: December 5, 1997

Creator: Allen, T. R. & Storey, B. G.

Object Type: Article

System: The UNT Digital Library

(open access)

Analysis of Enriched Uranium and Weapons Plutonium Reloads for PWRs Using BRACC

Comparisons of the multicycle results demonstrate that the correlation coefficients based on the CASMO3 data were implemented correctly and that the Linear Reactivity Model is acceptably accurate for missed reloads containing both uranium and weapons plutonium fuel. The expanded set of correlation coefficients make BRACC a useful tool for performing multi-cycle in-core fuel management studies of PWR cores containing weapons plutonium.

Date: June 5, 1997

Creator: Alonso, G. & Parish, T. A.

Object Type: Article

System: The UNT Digital Library

(open access)

Investigation of moisture-induced embrittlement of iron aluminides. Final report

Iron-aluminum alloys with 28 at.% Al and 5 at.% Cr were shown to be susceptible to hydrogen embrittlement by exposure to both gaseous hydrogen and water vapor. This study examined the effect of the addition of zirconium and carbon on the moisture-induced hydrogen embrittlement of an Fe{sub 3}Al,Cr alloy through the evaluation of tensile properties and fatigue crack growth resistance in hydrogen gas and moisture-bearing air. Susceptibility to embrittlement was found to vary with the zirconium content while the carbon addition was found to only affect the fracture toughness. Inherent fatigue crack growth resistance and fracture toughness, as measured in an inert environment, was found to increase with the addition of 0.5 at.% Zr. The combined addition of 0.5 at.% Zr and carbon only increased the fracture toughness. The addition of 1 at.% Zr and carbon was found to have no effect on the crack growth rate when compared to the base alloy. Susceptibility to embrittlement in moisture-bearing environments was found to decrease with the addition of 0.5 at.% Zr. In gaseous hydrogen, the threshold value of the Zr-containing alloys was found to increase above that found in the inert environment while the crack growth resistance was much lower. By …

Date: June 5, 1997

Creator: Alven, D. A. & Stoloff, N.S .

Object Type: Report

System: The UNT Digital Library

transcript

Oral History Interview with Ray Amstutz, April 5, 1997

The National Museum of the Pacific War presents an oral interview with Ray Amstutz. Amstutz joined the Army Reserve (Student Training Corps) while in college at the University of Tulsa. On May 8, 1943 he was inducted and went to Fort Sill, Oklahoma for processing and then to Camp Maxie, Paris, Texas for three months basic training. The Army sent him back to school at the University of Oklahoma where he finished one semester. From there, he went to Camp Claiborne in Louisiana where they were trained to lay pipelines, maintain and repair engines, construct tanks, maintain pumps, etc. Amstutz's unit was put aboard a train, shipped to Oakland, California and put aboard a Liberty ship which sailed for Milne Bay, New Guinea; this was August/September 1944. He provides a nice description of the environment aboard ship for the 18 days it took to get to New Guinea. From there, they moved to Ora Bay and started unloading their equipment at Buna where major battles had already taken place. In Buna, they went inland, built a little dam on a river, laid suction pipe down into it, set up some pumps, and laid pipeline back to the docks; filling up …

Date: April 5, 1997

Creator: Amstutz, Ray

Object Type: Sound

System: The Portal to Texas History