Resource Type

Dimensional errors in LIGA-produced metal structures due to thermal expansion and swelling of PMMA. (open access)

Dimensional errors in LIGA-produced metal structures due to thermal expansion and swelling of PMMA.

Numerical methods are used to examine dimensional errors in metal structures microfabricated by the LIGA process. These errors result from elastic displacements of the PMMA mold during electrodeposition and arise from thermal expansion of the PMMA when electroforming is performed at elevated temperatures and from PMMA swelling due to absorption of water from aqueous electrolytes. Both numerical solutions and simple analytical approximations describing PMMA displacements for idealized linear and axisymmetric geometries are presented and discussed. We find that such displacements result in tapered metal structures having sidewall slopes up to 14 {micro}m per millimeter of height for linear structures bounded by large areas of PMMA. Tapers for curved structures are of similar magnitude, but these structures are additionally skewed from the vertical. Potential remedies for reducing dimensional errors are also discussed. Here we find that auxiliary moat-like features patterned into the PMMA surrounding mold cavities can reduce taper by an order of magnitude or more. Such moats dramatically reduce tapers for all structures, but increase skew for curved structures when the radius of curvature is comparable to the structure height.
Date: April 1, 2004
Creator: Kistler, Bruce L.; Dryden, Andrew S.; Crowell, Jeffrey A.W. & Griffiths, Stewart K.
System: The UNT Digital Library
Predicted Effects of Prescribed Burning and Timber Management on Forest Recovery and Sustainability at Fort Benning, Georgia (open access)

Predicted Effects of Prescribed Burning and Timber Management on Forest Recovery and Sustainability at Fort Benning, Georgia

The objective of this work was to use a simple compartment model of soil carbon (C) and nitrogen (N) dynamics to predict forest recovery on degraded soils and forest sustainability, following recovery, under different regimes of prescribed fire and timber management. This report describes the model and a model-based analysis of the effect of prescribed burning and forest thinning or clearcutting on stand recovery and sustainability at Fort Benning, GA. I developed the model using Stella{reg_sign} Research Software (High Performance Systems, Inc., Hanover, NH) and parameterized the model using data from field studies at Fort Benning, literature sources, and parameter fitting. The model included (1) a tree biomass submodel that predicted aboveground and belowground tree biomass, (2) a litter production submodel that predicted the dynamics of herbaceous aboveground and belowground biomass, (3) a soil C and N submodel that predicted soil C and N stocks (to a 30 cm soil depth) and net soil N mineralization, and (4) an excess N submodel that calculated the difference between predicted plant N demands and soil N supplies. There was a modeled feedback from potential excess N (PEN) to tree growth such that forest growth was limited under conditions of N deficiency. Two …
Date: April 13, 2004
Creator: Garten, C. T. Jr.
System: The UNT Digital Library
Soil Carbon Dynamics Along an Elevation Gradient in the Southern Appalachian Mountains (open access)

Soil Carbon Dynamics Along an Elevation Gradient in the Southern Appalachian Mountains

The role of soil C dynamics in the exchange of CO{sub 2} between the terrestrial biosphere and the atmosphere is at the center of many science questions related to global climate change. The purpose of this report is to summarize measured trends in environmental factors and ecosystem processes that affect soil C balance along elevation gradients in the southern Appalachian Mountains of eastern Tennessee and western North Carolina, USA. Three environmental factors that have potentially significant effects on soil C dynamics (temperature, precipitation, and soil N availability) vary in a predictable manner with altitude. Forest soil C stocks and calculated turnover times of labile soil C increase with elevation, and there is an apparent inverse relationship between soil C storage and mean annual temperature. Relationships between climate variables and soil C dynamics along elevation gradients must be interpreted with caution because litter chemistry, soil moisture, N availability, and temperature are confounded; all potentially interact in complex ways to regulate soil C storage through effects on decomposition. Some recommendations are presented for untangling these complexities. It is concluded that past studies along elevation gradients have contributed to a better but not complete understanding of environmental factors and processes that potentially affect …
Date: April 13, 2004
Creator: Garten C. T. Jr.
System: The UNT Digital Library
History and testimony of competency-based development at Sandia National Laboratories. (open access)

History and testimony of competency-based development at Sandia National Laboratories.

More than ten years ago, Sandia managers defined a set of traits and characteristics that were needed for success at Sandia. Today, the Sandia National Laboratories Success Profile Competencies continue to be powerful tools for employee and leadership development. The purpose of this report is to revisit the historical events that led to the creation and adaptation of the competencies and to position them for integration in future employee selection, development, and succession planning processes. This report contains an account of how the competencies were developed, testimonies of how they are used within the organization, and a description of how they will be foundational elements of new processes.
Date: April 1, 2004
Creator: Burt, Rebecca A. & Narahara, Sheryl K.
System: The UNT Digital Library
Metals Processing Laboratory Users (MPLUS) Facility Annual Report FY 2002 (October 1, 2001-September 30, 2002) (open access)

Metals Processing Laboratory Users (MPLUS) Facility Annual Report FY 2002 (October 1, 2001-September 30, 2002)

The Metals Processing Laboratory Users Facility (MPLUS) is a Department of Energy (DOE), Energy Efficiency and Renewable Energy, Industrial Technologies Program, user facility designated to assist researchers in key industries, universities, and federal laboratories in improving energy efficiency, improving environmental aspects, and increasing competitiveness. The goal of MPLUS is to provide access to the specialized technical expertise and equipment needed to solve metals processing issues that limit the development and implementation of emerging metals processing technologies. The scope of work can also extend to other types of materials. MPLUS has four primary user centers: (1) Processing--casting, powder metallurgy, deformation processing (including extrusion, forging, rolling), melting, thermomechanical processing, and high-density infrared processing; (2) Joining--welding, monitoring and control, solidification, brazing, and bonding; (3) Characterization--corrosion, mechanical properties, fracture mechanics, microstructure, nondestructive examination, computer-controlled dilatometry, and emissivity; and (4) Materials/Process Modeling--mathematical design and analyses, high-performance computing, process modeling, solidification/deformation, microstructure evolution, thermodynamic and kinetic, and materials databases A fully integrated approach provides researchers with unique opportunities to address technologically related issues to solve metals processing problems and probe new technologies. Access is also available to 16 additional Oak Ridge National Laboratory (ORNL) user facilities ranging from state-of-the-art materials characterization capabilities, and high-performance computing to …
Date: April 27, 2004
Creator: Angelini, P
System: The UNT Digital Library
Tonopah Test Range Post-Closure Inspection Annual Report, Tonopah Test Range, Nevada, Calendar Year 2003 (open access)

Tonopah Test Range Post-Closure Inspection Annual Report, Tonopah Test Range, Nevada, Calendar Year 2003

This post-closure inspection report provides documentation of the semiannual inspection activities, maintenance and repair activities, and conclusions and recommendations for calendar year 2003 for eight corrective action units located on the Tonopah Test Range, Nevada.
Date: April 1, 2004
Creator: United States. National Nuclear Security Administration. Nevada Site Office.
System: The UNT Digital Library
An Assessment of Future Demands for and Benefits of Public Transit Srevices in Tennessee (open access)

An Assessment of Future Demands for and Benefits of Public Transit Srevices in Tennessee

This report documents results from a study carried out by Oak Ridge National Laboratory and the University of Tennessee at Knoxville for the Office of Public Transportation, Tennessee Department of Transportation. The study team was tasked with developing a process and a supporting methodology for estimating the benefits accruing to the State from the operation of state supported public transit services. The team was also tasked with developing forecasts of the future demands for these State supported transit services at five year intervals through the year 2020, broken down where possible to the local transit system level. Separate ridership benefits and forecasts were also requested for the State's urban and rural transit operations. Tennessee's public transit systems are subsidized to a degree by taxpayers. It is therefore in the public interest that assessments of the benefits of such systems be carried out at intervals, to determine how they are contributing to the well-being of the state's population. For some population groups within the State of Tennessee these transit services have become essential as a means of gaining access to workplaces and job training centers, to educational and health care facilities, as well as to shops, social functions and recreational sites.
Date: April 29, 2004
Creator: Southworth, F.
System: The UNT Digital Library
Large batch dimensional metrology demonstrated in the example of a LIGA fabricated spring. (open access)

Large batch dimensional metrology demonstrated in the example of a LIGA fabricated spring.

Deep x-ray lithography in combination with electroforming is capable of producing high precision metal parts in small lot series. This study deals with a high aspect ratio structure with overall dimensions on the order of 10 mm x 7 mm x 1.5 mm, with the smallest line width being 150 {micro}m. The lateral deviation from the design is to be kept to a minimum, preferably below 5 {micro}m. To ensure adequate quality control, a semi-automated metrology technique has been established to measure all parts. While the paper will give a brief overview of all involved techniques, it focuses on the method to measure the top and bottom of the parts and the top of geometries following the process. The instrument used is a View Engineering Voyager V6x12 microscope, which is fully programmable. The microscope allows direct measurement of geometries but also is capable of saving all captured data as point clouds. These point clouds play a central role when evaluating part geometry. After measuring the part, the point cloud is compared to the computer aided design (CAD) contour of the part, using a commercially available software package. The challenge of proper edge lighting on a nickel alloy part is evaluated …
Date: April 1, 2004
Creator: Aigeldinger, Georg; Skala, Dawn M. & Ceremuga, Joseph T.
System: The UNT Digital Library
NIF HEPW 2D Radiography Option Survey (open access)

NIF HEPW 2D Radiography Option Survey

None
Date: April 28, 2004
Creator: Koch, J
System: The UNT Digital Library
A Measurement of the Top Quark Mass with the D0 Detector at s**(1/2) = 1.96-TeV using the Matrix Element Method (open access)

A Measurement of the Top Quark Mass with the D0 Detector at s**(1/2) = 1.96-TeV using the Matrix Element Method

Using a data set of 158 and 169 pb{sup -1} of D0 Run-II data in the electron and muon plus jets channel, respectively, the top quark mass has been measured using the Matrix Element Method. The method and its implementation are described. Its performance is studied in Monte Carlo using ensemble tests and the method is applied to the Moriond 2004 data set.
Date: April 1, 2004
Creator: Kroeninger, Kevin Alexander
System: The UNT Digital Library
3D Computations and Experiments (open access)

3D Computations and Experiments

This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.
Date: April 5, 2004
Creator: Couch, R; Faux, D; Goto, D & Nikkel, D
System: The UNT Digital Library
Introduction to Building Systems Performance: Houses That Work II; Period of Performance: January 2003--December 2003 (open access)

Introduction to Building Systems Performance: Houses That Work II; Period of Performance: January 2003--December 2003

Buildings should be suited to their environments. Design and construction must be responsive to varying seismic risks, wind loads, and snow loads, as well as soil conditions, frost depth, orientation, and solar radiation. In addition, building envelopes and mechanical systems should be designed for a specific hygro-thermal regions, rain exposure, and interior climate. The Building Science Consortium (BSC) design recommendations are based on the hygro-thermal regions with reference to the annual rainfall. Local climate must be addressed if it differs significantly from the climate described for a particular design.
Date: April 1, 2004
Creator: unknown
System: The UNT Digital Library
Integration Architecture Capability Case Model (open access)

Integration Architecture Capability Case Model

None
Date: April 16, 2004
Creator: Watts, R A
System: The UNT Digital Library
Precision Micron Hole Drilling using a Frequency Doubled, Diode Pumped Solid State Laser (open access)

Precision Micron Hole Drilling using a Frequency Doubled, Diode Pumped Solid State Laser

This work represents the second phase of a program to demonstrate precision laser drilling with minimal Heat Affected Zone. The technique uses a Diode Pumped Solid State Laser with two wavelengths and two modes of operation. The fundamental mode of the DPSSL at 1.06 microns is used to drill a hole with a diameter of a fraction of a millimeter diameter in a millimeter thick substrate quickly, but with low precision. This hole is then machined to precision dimensions using the second harmonic of the DPSSL Laser at 532 nm using a trepanning technique. Both lasers operate in the ablative mode with peak powers at or above a giga-watt per square centimeter and pulse durations in the 80 - 100 ns range. Under these conditions, the thermal diffusion distance is of the order of a micron or less and that fact coupled with the ablative nature of the process results in little or no HAZ (heat affected zone). With no HAZ, there isn't any change in the crystalline structure surrounding the hole and the strength of the substrate is maintained. Applications for these precision holes include cooling passages in turbine blades, ports for diesel injectors, suction holes for boundary layer …
Date: April 21, 2004
Creator: Friedman, H W & Pierce, E L
System: The UNT Digital Library
Adaptive 4-8 Texture Hierarchies (open access)

Adaptive 4-8 Texture Hierarchies

None
Date: April 14, 2004
Creator: Hwa, L M; Duchaineau, M A & Joy, K I
System: The UNT Digital Library
D-Zero HVAC Heat Pump Controls (open access)

D-Zero HVAC Heat Pump Controls

This engineering note documents the integration of Dzero Heat Pump 1 through Heat Pump 15 into the cryo/gas process control system commonly referred to as the cryo control system. Heat pumps 1 through 15 control the ambient air temperature on the 3rd, 5th, and 6th floor office areas at Dzero. The entire Johnson HVAC control system was replaced with a Siemens control system in 1999 leaving behind the 15 heat pumps with stand-alone Johnson controllers. Now, these 15 heat pump Johnson controllers are being replaced with small stand alone Beckhoff BC9000 controllers. The Beckhoff BC9000 controllers are network able into the existing Intellution control system. The Beckhoff BC9000 controllers use the cryo private Ethernet network and an OPC driver to get data into the Intellution SCADA node databases. The BC9000 is also programmed over this same Ethernet network.
Date: April 14, 2004
Creator: Markley, Dan
System: The UNT Digital Library
Electron Cloud Phase Transitions (open access)

Electron Cloud Phase Transitions

N/A
Date: April 1, 2004
Creator: U., Iriso & Peggs, S.
System: The UNT Digital Library
Final Phase II Report : QuickSite{reg_sign} investigation, Centralia, Kansas. (open access)

Final Phase II Report : QuickSite{reg_sign} investigation, Centralia, Kansas.

The Commodity Credit Corporation (CCC), an agency of the U.S. Department of Agriculture (USDA), formerly operated a grain storage facility approximately 1,100 ft north of Centralia from 1949 until 1971. Subsequently, a concrete mixing plant operated on the site (FSA 1997). None of the CCC/USDA structures remain, though belowgrade foundations related to structures associated with the concrete mixing operations are evident. Two additional grain storage facilities currently exist in and near Centralia: the Nemaha County Co-op, approximately 4,000 ft south of the former CCC/USDA facility, and a private grain storage facility near the Don Morris residence, 3,500 ft north of the former CCC/USDA facility (Figure 1.1). The property on which the former facility was located is currently owned by Jeanne Burdett Lacky of Seneca, Kansas. In August-September 1998 the Kansas Department of Health and Environment (KDHE) conducted preliminary investigations at the former CCC/USDA facility, on the basis of the detection of carbon tetrachloride in the domestic well at the Don Morris residence (north of the former CCC/USDA facility). Prior to 1986, commercial grain fumigants containing carbon tetrachloride were commonly used by the CCC/USDA and the grain storage industry to preserve grain. The details of previous investigations in the area and …
Date: April 1, 2004
Creator: LaFreniere, L. (Environmental Research)
System: The UNT Digital Library
A reformulation of intrabeam scattering theory (open access)

A reformulation of intrabeam scattering theory

N/A
Date: April 1, 2004
Creator: Parzen, G.
System: The UNT Digital Library
Results from ORNL Characterization of Archive German Particles (open access)

Results from ORNL Characterization of Archive German Particles

This document is a compilation of the characterization data obtained on a sample of TRISO-coated 500 {micro}m UO{sub 2} produced by the Germans and obtained by the AGR program for use as a reference material. This sample came from the EUO 2358-2365 composite studied by General Atomics (GA) and referenced in GA document No.910852 'Acceptance Test report for German Fuel Particles'. The ORNL designation for the material characterized was AGR-06.
Date: April 1, 2004
Creator: Hunn, John D
System: The UNT Digital Library
MOAB : a mesh-oriented database. (open access)

MOAB : a mesh-oriented database.

A finite element mesh is used to decompose a continuous domain into a discretized representation. The finite element method solves PDEs on this mesh by modeling complex functions as a set of simple basis functions with coefficients at mesh vertices and prescribed continuity between elements. The mesh is one of the fundamental types of data linking the various tools in the FEA process (mesh generation, analysis, visualization, etc.). Thus, the representation of mesh data and operations on those data play a very important role in FEA-based simulations. MOAB is a component for representing and evaluating mesh data. MOAB can store structured and unstructured mesh, consisting of elements in the finite element 'zoo'. The functional interface to MOAB is simple yet powerful, allowing the representation of many types of metadata commonly found on the mesh. MOAB is optimized for efficiency in space and time, based on access to mesh in chunks rather than through individual entities, while also versatile enough to support individual entity access. The MOAB data model consists of a mesh interface instance, mesh entities (vertices and elements), sets, and tags. Entities are addressed through handles rather than pointers, to allow the underlying representation of an entity to change …
Date: April 1, 2004
Creator: Tautges, Timothy James; Ernst, Corey; Stimpson, Clint; Meyers, Ray J. & Merkley, Karl
System: The UNT Digital Library
Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation; Coeur d'Alene Tribe Fish, Water, and Wildlife Program, REVISED 2002 Annual Report. (open access)

Implementation of Fisheries Enhancement Opportunities on the Coeur d'Alene Reservation; Coeur d'Alene Tribe Fish, Water, and Wildlife Program, REVISED 2002 Annual Report.

Historically, the Coeur d'Alene Indian Tribe depended on runs of anadromous salmon and steelhead along the Spokane River and Hangman Creek, as well as resident and adfluvial forms of trout and char in Coeur d'Alene Lake, for survival. Dams constructed in the early 1900s on the Spokane River in the City of Spokane and at Little Falls (further downstream) were the first dams that initially cut-off the anadromous fish runs from the Coeur d'Alene Tribe. These fisheries were further removed by the construction of Chief Joseph and Grand Coulee Dams on the Columbia River. Together, these actions forced the Tribe to rely solely on the resident fish resources of Coeur d'Alene Lake (Staff Communication). The Coeur d'Alene Tribe is estimated to have historically harvested around 42,000 westslope cutthroat trout (Oncorhynchus clarki) per year (Scholz et al. 1985). In 1967, Mallet (1969) reported that 3,329 cutthroat were harvested from the St. Joe River, and a catch of 887 was reported from Coeur d'Alene Lake. This catch is far less than the 42,000 fish per year the tribe harvested historically. Today, only limited opportunities exist to harvest cutthroat trout in the Coeur d'Alene Basin. The declines in native salmonid fish populations, particularly …
Date: April 1, 2004
Creator: Vitale, Angelo; Lamb, Dave & Scott, Jason
System: The UNT Digital Library
Design of a 2 Slot VLPC Cryostat Cooled by a Cryocooler (open access)

Design of a 2 Slot VLPC Cryostat Cooled by a Cryocooler

The conceptual design and preliminary engineering calculations have been completed for a two cassette cryostat. This report summarizes the design. A cryocooler is permanently mounted in the center of a stainless steel, 0.75 inch thick top lid. The cryocooler sits upon a spacer which raises the cooling stage elevations to favorably match the cassette heat intercept elevations. The top lid (32.0-inch outside diameter) mates to a 24-inch pipe size flange with o-ring. The 24-inch pipe size vacuum vessel with end plate has a minimum internal depth of 16-inch to give adequate clearance for the depth of the cryocooler and multilayer insulation blankets. Support stand legs elevate the container to a convenient height and allow for placement of the AFE power supply underneath. Two cassette slots are located on either side of the cryocooler. The slots are positioned parallel to each other, 10.5-inch center to center (6 standard cassette slot widths) so that the standard 8 slot AFE backplane can be used. The slot opening through the lid is approximately 1.422-inch x 16.782-inch. A 0.016-inch thick titanium (Ti-6AI-4V) envelope with sealing lip is inserted through lid and defines the gas helium boundary that the VLPC cassette resides. The internal dimensions of …
Date: April 22, 2004
Creator: Rucinski, Russell A.
System: The UNT Digital Library
Study of metal dusting phenomenon and development of materials resistant to metal dusting. Final report. (open access)

Study of metal dusting phenomenon and development of materials resistant to metal dusting. Final report.

None
Date: April 5, 2004
Creator: Natesan, K. & Zeng, Z.
System: The UNT Digital Library