The advantages of evaporation of Hafnium in a reactive environment to manufacture high damage threshold multilayer coatings by electron-beam deposition (open access)

The advantages of evaporation of Hafnium in a reactive environment to manufacture high damage threshold multilayer coatings by electron-beam deposition

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Date: April 22, 1999
Creator: Bevis, R. P.; Sheehan, L. M.; Smith, D. J.; Stolz, C. J. & Von Gunten, M. K.
Object Type: Article
System: The UNT Digital Library
Oxidation-resistant interfacial coatings for fiber-reinforced ceramic composites (open access)

Oxidation-resistant interfacial coatings for fiber-reinforced ceramic composites

A ceramic-matrix composite having a multilayered interfacial coating adapted to protect the reinforcing fibers from long-term oxidation, while allowing these to bridge the wake of advancing cracks in the matrix, is provided by selectively mismatching materials within adjacent layers of the interfacial coating, the materials having different coefficients of thermal expansion so that a low toughness interface region is created to promote crack deflection either within an interior layer of the mismatched interfacial coating or between adjacent layers of the mismatched interfacial coating.
Date: April 22, 1999
Creator: Lara-Curzio, Edgar; More, Karren L. & Lee, Woo Y.
Object Type: Patent
System: The UNT Digital Library
Brandon Research, Inc. Orthopedic Implant Cooperative Research and Development Agreement (CRADA) Final Report (open access)

Brandon Research, Inc. Orthopedic Implant Cooperative Research and Development Agreement (CRADA) Final Report

The project was a joint research effort between the U. S. Department of Energy's (DOE) Kansas City Plant (KCP) and Brandon Research, Inc. to develop ways to improve implants used for orthopedic surgery for joint replacement. The primary product produced by this study is design information, which may be used to develop implants that will improve long-term fixation and durability in the host bone environment.
Date: April 22, 1999
Creator: Freeman, W.R.
Object Type: Report
System: The UNT Digital Library
Uranium industry annual 1998 (open access)

Uranium industry annual 1998

The Uranium Industry Annual 1998 (UIA 1998) provides current statistical data on the US uranium industry`s activities relating to uranium raw materials and uranium marketing. It contains data for the period 1989 through 2008 as collected on the Form EIA-858, ``Uranium Industry Annual Survey.`` Data provides a comprehensive statistical characterization of the industry`s activities for the survey year and also include some information about industry`s plans and commitments for the near-term future. Data on uranium raw materials activities for 1989 through 1998, including exploration activities and expenditures, EIA-estimated reserves, mine production of uranium, production of uranium concentrate, and industry employment, are presented in Chapter 1. Data on uranium marketing activities for 1994 through 2008, including purchases of uranium and enrichment services, enrichment feed deliveries, uranium fuel assemblies, filled and unfilled market requirements, and uranium inventories, are shown in Chapter 2. The methodology used in the 1998 survey, including data edit and analysis, is described in Appendix A. The methodologies for estimation of resources and reserves are described in Appendix B. A list of respondents to the ``Uranium Industry Annual Survey`` is provided in Appendix C. The Form EIA-858 ``Uranium Industry Annual Survey`` is shown in Appendix D. For the readers …
Date: April 22, 1999
Creator: unknown
Object Type: Report
System: The UNT Digital Library
A Convergence Analysis of Unconstrained and Bound Constrained Evolutionary Pattern Search (open access)

A Convergence Analysis of Unconstrained and Bound Constrained Evolutionary Pattern Search

The authors present and analyze a class of evolutionary algorithms for unconstrained and bound constrained optimization on R{sup n}: evolutionary pattern search algorithms (EPSAs). EPSAs adaptively modify the step size of the mutation operator in response to the success of previous optimization steps. The design of EPSAs is inspired by recent analyses of pattern search methods. They show that EPSAs can be cast as stochastic pattern search methods, and they use this observation to prove that EpSAs have a probabilistic weak stationary point convergence theory. This work provides the first convergence analysis for a class of evolutionary algorithms that guarantees convergence almost surely to a stationary point of a nonconvex objective function.
Date: April 22, 1999
Creator: Hart, W.E.
Object Type: Article
System: The UNT Digital Library
Heat Treat of 3Z Valve Piston (open access)

Heat Treat of 3Z Valve Piston

To improve the processing of 3Z valve pistons in LF7 assemblies, material qualities are being investigated. After a review of the fracture toughness curve, it was noted that a change of a few degrees variation from the 900 F called for by the drawing would affect the fracture toughness of the product. After this observation it was decided to determine how close to the 900 F the parts were heat-treated. The subsequent study indicated that Federal Manufacturing & Technologies (FM&T) equipment held the product at 900 F {+-} 1.8 F.
Date: April 22, 1999
Creator: Hern, P.J.
Object Type: Report
System: The UNT Digital Library
Final technical report for project industrial technology opportunities in the chemicals industry through cleaner raw materials identification (open access)

Final technical report for project industrial technology opportunities in the chemicals industry through cleaner raw materials identification

Report on progress made in both NRDC's work on impurities in raw materials and the pollution prevention work with Dow Chemical during the period of 10/1/98 through 1/31/99.
Date: April 22, 1999
Creator: Greer, L.
Object Type: Report
System: The UNT Digital Library
Room-temperature laser action at 4.3--4.4 {micro}m in CaGa{sub 2}S{sub 4}:Dy{sup 3+} (open access)

Room-temperature laser action at 4.3--4.4 {micro}m in CaGa{sub 2}S{sub 4}:Dy{sup 3+}

The authors report room-temperature mid-IR laser operation in a new low-phonon-frequency, non-hygroscopic host crystal CaGa{sub 2}S{sub 4} (calcium thiogallate). Laser action at 4.31 {micro}m on the {sup 6}H{sub 11/2} {r_arrow}{sup 6}H{sub 13/2} transition of trivalent dysprosium was achieved with a slope efficiency of 1.6%.
Date: April 22, 1999
Creator: Nostrand, M; Page, R H; Payne, S A; Krupke, W F & Schunemann
Object Type: Article
System: The UNT Digital Library
Intracavity Frequency Doubling of a Diode-Pumped, External Cavity, Surface Emitting Semiconductor Laser (open access)

Intracavity Frequency Doubling of a Diode-Pumped, External Cavity, Surface Emitting Semiconductor Laser

The authors present a compact, robust, solid-state blue light (490 nm) source capable of greater than 5 mW of output in a TEM{sub 00} mode. This device is an optically pumped, vertical external-cavity surface-emitting laser (VECSEL) with an intracavity frequency doubling crystal.
Date: April 22, 1999
Creator: Alford, W. J.; Allerman, A. A.; Crawford, M. H. & Raymond, T. D.
Object Type: Article
System: The UNT Digital Library
In-situ, real-time, studies of film growth processes using ion scattering and direct recoil spectroscopy techniques. (open access)

In-situ, real-time, studies of film growth processes using ion scattering and direct recoil spectroscopy techniques.

Time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) enables the characterization of the composition and structure of surfaces with 1-2 monolayer specificity. It will be shown that surface analysis is possible at ambient pressures greater than 3 mTorr using TOF-ISARS techniques; allowing for real-time, in situ studies of film growth processes. TOF-ISARS comprises three analytical techniques: ion scattering spectroscopy (ISS), which detects the backscattered primary ion beam; direct recoil spectroscopy (DRS), which detects the surface species recoiled into the forward scattering direction; and mass spectroscopy of recoiled ions (MSRI), which is 3 variant of DRS capable of isotopic resolution for all surface species--including H and He. The advantages and limitations of each of these techniques will be discussed. The use of the three TOF-ISARS methods for real-time, in situ film growth studies at high ambient pressures will be illustrated. It will be shown that MSRI analysis is possible during sputter deposition. It will be also be demonstrated that the analyzer used for MSRI can also be used for time of flight secondary ion mass spectroscopy (TOF-SIMS) under high vacuum conditions. The use of a single analyzer to perform the complimentary surface analytical techniques of MSRI and SIMS is unique. The dwd …
Date: April 22, 1999
Creator: Smentkowski, V. S.
Object Type: Article
System: The UNT Digital Library