Nanoscale investigation of polarization retention loss in ferroelectric thin films via scanning force microscopy. (open access)

Nanoscale investigation of polarization retention loss in ferroelectric thin films via scanning force microscopy.

Scanning force microscopy (SFM) was applied to direct nanoscale investigation of the mechanism of retention loss in ferroelectric thin films. Experiments were conducted by performing local polarization reversal within an individual grain with subsequent imaging of a resulting domain structure at various time intervals. A conductive SFM tip was used for domain switching and imaging in the SFM piezoresponse mode.
Date: February 12, 1998
Creator: Aggarwal, S.; Auciello, O.; Gruverman, A.; Prakash, S. A.; Ramesh, R. & Tokumoto, H.
Object Type: Article
System: The UNT Digital Library
Sputter deposited beryllium fuel capsules for NIF (open access)

Sputter deposited beryllium fuel capsules for NIF

The objective of our effort is to systematically study the properties of films produced under different conditions, with an emphasis on improving surface morphology and microstructure while studying permeability and capsule strength. We have made extensive use of atomic force and electron microscopy to determine the microstructure of the films, along with composition probes (mainly x-ray fluorescence) to quantify the chemical structure. Our studies can be roughly divided into three categories. First, there are those in which the effects of substrate biasing have been investigated. This includes varying the substrate voltage from 0 to 120 V and applying an intermittent bias. Next there are studies of Be combined with boron, a non-soluble dopant Because of it`s low Z this dopant is of particular interest for x-ray related applications. Finally, there are experiments in which pulses of nitrogen are admitted to the vacuum chamber during deposition. The layers of nitride formed tended to disrupt the growth of Be grains, leading to a more fine-grained microstructure. For all these studies, we have most often used hollow plastic spheres for our substrate material. However, there have been some samples deposited on glass spheres or silicon flats.
Date: February 12, 1998
Creator: Alford, C.S.
Object Type: Report
System: The UNT Digital Library
Estimation of fatigue strain-life curves for austenitic stainless steels in light water reactor environments. (open access)

Estimation of fatigue strain-life curves for austenitic stainless steels in light water reactor environments.

The ASME Boiler and Pressure Vessel Code design fatigue curves for structural materials do not explicitly address the effects of reactor coolant environments on fatigue life. Recent test data indicate a significant decrease in fatigue lives of austenitic stainless steels (SSs) in light water reactor (LWR) environments. Unlike those of carbon and low-alloy steels, environmental effects on fatigue lives of SSs are more pronounced in low-dissolved-oxygen (low-DO) water than in high-DO water, This paper summarizes available fatigue strain vs. life data on the effects of various material and loading variables such as steel type, DO level, strain range, and strain rate on the fatigue lives of wrought and cast austenitic SSs. Statistical models for estimating the fatigue lives of these steels in LWR environments have been updated with a larger data base. The significance of the effect of environment on the current Code design curve has been evaluated.
Date: February 12, 1998
Creator: Chopra, O. K. & Smith, J. L.
Object Type: Article
System: The UNT Digital Library
High-average-power diode-end-pumped intracavity-doubled Nd:YAG laser (open access)

High-average-power diode-end-pumped intracavity-doubled Nd:YAG laser

A compact diode-pumped ND:YAG laser was frequency-doubled to 0.532 {mu}m with an intracavity KTP or LBO crystal using a `V` cavity configuration. Two acousto-optic Q-switches were employed at repetition rates of 10-30 kHz. Dichroic fold and end mirrors were used to output two beams with up to 140 W of 0.532 {mu}m power using KTP and 116 W using LBO as the frequency doubling crystal. This corresponds to 66% of the maximum output power at 1.064 {mu}m obtained with an optimized output coupler reflectivity. The minimum output pulse duration varied with repetition rate from 90 to 130 ns. The multimode output beam had a smooth profile and a beam quality of M{sup 2} = 5 1.
Date: February 12, 1998
Creator: Honea, E. C.; Ebbers, C. A.; Beach, R. J.; Speth, J. A.; Emanuel, M. S.; Skidmore, J. A. et al.
Object Type: Article
System: The UNT Digital Library
Specification for soil multisensor and soil sampling cone penetrometer probes (open access)

Specification for soil multisensor and soil sampling cone penetrometer probes

Specification requirements for engineering, fabrication, and performance of cone penetrometer (CP) soil multisensor and sampling probes (CP-probes). Required to support contract procurement for services. The specification provides a documented technical basis of quality assurance that is required to use the probes in an operating Hanford tank farm. The documentation cited in this specification will be referenced as part of a readiness review and engineering task plan for a planned FY-1998 in-tank-farm CP-probe fielding task (demonstration). The probes discussed in this specification support the Hanford Tanks Initiative AX-104 Tank Plume Characterization Sub-task. The probes will be used to interrogate soils and vadose zone surrounding tank AX-104.
Date: February 12, 1998
Creator: Iwatate, D. F.
Object Type: Report
System: The UNT Digital Library
Metals Processing Laboratory User Facility: Facilities capabilities; Interactive programs; Recent experience (open access)

Metals Processing Laboratory User Facility: Facilities capabilities; Interactive programs; Recent experience

MPLUS is a DOE designated User Facility providing extensive Technical Expertise and Specialized Facilities to assist Industrial and Academic Partners in becoming more Energy Efficient and enhancing US Competitiveness in the World market. MPLUS focusing on 7 major vision industries (aluminum, chemical, forest products, glass, metals castings, refineries, and steel) identified by DOE as being energy intensive, as well as cross-cutting industries such as welding and heat treating. MPLUS consists of four primary facilities: (1) Materials Processing, (2) Materials Joining, (3) Materials Characterization and Properties, and (4) Materials Process Modeling. Each facility provides rapid access to unique, state-of-the-art equipment, capabilities, and technical expertise necessary for solving materials processing issues that limit the development and implementation of emerging technologies. These capabilities include: (1) materials synthesis; (2) deformation processing; (3) materials characterization; (4) joining and mathematical modeling.
Date: February 12, 1998
Creator: Mackiewicz-Ludtka, G. & Raschke, R.A.
Object Type: Report
System: The UNT Digital Library
Criticality safety evaluation report for the Cold Vacuum Drying Facility`s process water handling system (open access)

Criticality safety evaluation report for the Cold Vacuum Drying Facility`s process water handling system

This report addresses the criticality concerns associated with process water handling in the Cold Vacuum Drying Facility (CVDF). The controls and limitations on equipment design and operations to control potential criticality occurrences are identified. The effectiveness of equipment design and operation controls in preventing criticality occurrences during normal and abnormal conditions is evaluated and documented in this report. Spent nuclear fuel (SNF) is removed from existing canisters in both the K East and K West Basins and loaded into a multicanister overpack (MCO) in the K Basin pool. The MCO is housed in a shipping cask surrounded by clean water in the annulus between the exterior of the MCO and the interior of the shipping cask. The fuel consists of spent N Reactor and some single pass reactor fuel. The MCO is transported to the CVDF near the K Basins to remove process water from the MCO interior and from the shipping cask annulus. After the bulk water is removed from the MCO, any remaining free liquid is removed by drawing a vacuum on the MCO`s interior. After cold vacuum drying is completed, the MCO is filled with an inert cover gas, the lid is replaced on the shipping cask, …
Date: February 12, 1998
Creator: Roblyer, S. D.
Object Type: Report
System: The UNT Digital Library
Microscopic calculations of {lambda} single-particle energies. (open access)

Microscopic calculations of {lambda} single-particle energies.

{Lambda} binding energy data for total baryon number A {le} 208 and for {Lambda} angular momenta {ell}{sub {Lambda}} {le} 3 are analyzed in terms of phenomenological (but generally consistent with meson-exchange) {Lambda}N and {Lambda}NN potentials. The Fermi-Hypernetted-Chain technique is used to calculate the expectation values for the {Lambda} binding to nuclear matter. Accurate effective {Lambda}N and {Lambda}NN potentials are obtained which are folded with the core nucleus nucleon densities to calculate the {Lambda} single particle potential U{sub {Lambda}}(r). We use a dispersive {Lambda}NN potential but also include an explicit {rho} dependence to allow for reduced repulsion in the surface, and the best fits have a large {rho} dependence giving consistency with the variational Monte Carlo calculations for {sub {Lambda}}{sup 5}He. The exchange fraction of the {Lambda}N space-exchange potential is found to be 0.2-0.3 corresponding to m{sub {Lambda}}* {approx_equal} (0.74-0.82)m{sub {Lambda}}. Charge symmetry breaking is found to be significant for heavy hypernuclei with a large neutron excess, with a strength consistent with that obtained from the A = 4 hypernuclei.
Date: February 12, 1998
Creator: Usmani, Q. N.
Object Type: Article
System: The UNT Digital Library
Thick-Restart Lanczos Method for Symmetric EigenvalueProblems (open access)

Thick-Restart Lanczos Method for Symmetric EigenvalueProblems

None
Date: February 12, 1998
Creator: Wu, Kesheng & Simon, Horst D.
Object Type: Article
System: The UNT Digital Library
Practical superconductor development for electrical power applications quarterly report for the period ending December 31, 1997. (open access)

Practical superconductor development for electrical power applications quarterly report for the period ending December 31, 1997.

This is a multiyear experimental research program focused on improving relevant material properties of high-T{sub c} superconductors and on development of fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of this program. Recent work on microstructural development and current distribution in Bi-2223 powder-in-tube tapes and a novel application for high-temperature superconductors are discussed.
Date: February 12, 1998
Creator: unknown
Object Type: Report
System: The UNT Digital Library