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Some attributes of a language for property-based testing. (open access)

Some attributes of a language for property-based testing.

Property-based testing is a testing technique that evaluates executions of a program. The method checks that specifications, called properties, hold throughout the execution of the program. TASpec is a language used to specify these properties. This paper compares some attributes of the language with the specification patterns used for model-checking languages, and then presents some descriptions of properties that can be used to detect common security flaws in programs. This report describes the results of a one year research project at the University of California, Davis, which was funded by a University Collaboration LDRD entitled ''Property-based Testing for Cyber Security Assurance''.
Date: November 1, 2004
Creator: Neagoe, Vicentiu (University of California, Davis, CA) & Bishop, Matt (University of California, Davis, CA)
System: The UNT Digital Library
Temperature rise of the mask-resist assembly during LIGA exposure. (open access)

Temperature rise of the mask-resist assembly during LIGA exposure.

Deep X-ray lithography on PMMA resist is used in the LIGA process. The resist is exposed to synchrotron X-rays through a patterned mask and then is developed in a liquid developer to make high aspect ratio microstructures. The limitations in dimensional accuracies of the LIGA generated microstructure originate from many sources, including synchrotron and X-ray physics, thermal and mechanical properties of mask and resist, and from the kinetics of the developer. This work addresses the thermal analysis and temperature rise of the mask-resist assembly during exposure in air at the Advanced Light Source (ALS) synchrotron. The concern is that dimensional errors generated at the mask and the resist due to thermal expansion will lower the accuracy of the lithography. We have developed a three-dimensional finite-element model of the mask and resist assembly that includes a mask with absorber, a resist with substrate, three metal holders, and a water-cooling block. We employed the LIGA exposure-development software LEX-D to calculate volumetric heat sources generated in the assembly by X-ray absorption and the commercial software ABAQUS to calculate heat transfer including thermal conduction inside the assembly, natural and forced convection, and thermal radiation. at assembly outer and/or inner surfaces. The calculations of assembly …
Date: November 1, 2004
Creator: Ting, Aili
System: The UNT Digital Library
Alignment of the MINOS FD (open access)

Alignment of the MINOS FD

The results and procedure of the alignment of the MINOS Far Detector are presented. The far detector has independent alignments of SM1 and SM2. The misalignments have an estimated uncertainty of {approx}850 {micro}m for SM1 and {approx}750 {micro}m for SM2. The alignment has as inputs the average rotations of U and V as determined by optical survey and strip positions within modules measured from the module mapper. The output of this is a module-module correction for transverse mis-alignments. These results were verified by examining an independent set of data. These alignment constants on average contribute much less then 1% to the total uncertainty in the transverse strip position.
Date: November 1, 2004
Creator: Becker, B. & Boehnlein, D.
System: The UNT Digital Library
Matrixed business support comparison study. (open access)

Matrixed business support comparison study.

The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.
Date: November 1, 2004
Creator: Parsons, Josh D.
System: The UNT Digital Library
Red River Wildlife Management Area HEP Report, Habitat Evaluation Procedures, Technical Report 2004. (open access)

Red River Wildlife Management Area HEP Report, Habitat Evaluation Procedures, Technical Report 2004.

A habitat evaluation procedures (HEP) analysis conducted on the 314-acre Red River Wildlife Management Area (RRWMA) managed by the Idaho Department of Fish and Game resulted in 401.38 habitat units (HUs). Habitat variables from six habitat suitability index (HSI) models, comprised of mink (Mustela vison), mallard (Anas platyrhynchos), common snipe (Capella gallinago), black-capped chickadee (Parus altricapillus), yellow warbler (Dendroica petechia), and white-tailed deer (Odocoileus virginianus), were measured by Regional HEP Team (RHT) members in August 2004. Cover types included wet meadow, riverine, riparian shrub, conifer forest, conifer forest wetland, and urban. HSI model outputs indicate that the shrub component is lacking in riparian shrub and conifer forest cover types and that snag density should be increased in conifer stands. The quality of wet meadow habitat, comprised primarily of introduced grass species and sedges, could be improved through development of ephemeral open water ponds and increasing the amount of persistent wetland herbaceous vegetation e.g. cattails (Typha spp.) and bulrushes (Scirpus spp.).
Date: November 1, 2004
Creator: Ashley, Paul
System: The UNT Digital Library
LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461). (open access)

LDRD final report on new homogeneous and supported oligomerization catalysts (LDRD 42461).

The overall purpose of this LDRD is multifold. First, we are interested in preparing new homogeneous catalysts that can be used in the oligomerization of ethylene and in understanding commercially important systems better. Second, we are interested in attempting to support these new homogeneous catalysts in the pores of nano- or mesoporous materials in order to force new and unusual distributions of a-olefins to be formed during the oligomerization. Thus the overall purpose is to try to prepare new catalytic species and to possibly control the active site architecture in order to yield certain desired products during a catalytic reaction, much like nature does with enzymes. In order to rationally synthesize catalysts it is imperative to comprehend the function of the various components of the catalyst. In heterogeneous systems, it is of utmost importance to know how a support interacts with the active site of the catalyst. In fact, in the catalysis world this lack of fundamental understanding of the relationship between active site and support is the single largest reason catalysis is considered an 'empirical' or 'black box' science rather than a well-understood one. In this work we will be preparing novel ethylene oligomerization catalysts, which are normally P-O …
Date: November 1, 2004
Creator: Hascall, Anthony G. & Kemp, Richard Alan
System: The UNT Digital Library
Self-assembled ordered carbon-nanotube arrays and membranes. (open access)

Self-assembled ordered carbon-nanotube arrays and membranes.

Imagine free-standing flexible membranes with highly-aligned arrays of carbon nanotubes (CNTs) running through their thickness. Perhaps with both ends of the CNTs open for highly controlled nanofiltration? Or CNTs at heights uniformly above a polymer membrane for a flexible array of nanoelectrodes or field-emitters? How about CNT films with incredible amounts of accessible surface area for analyte adsorption? These self-assembled crystalline nanotubes consist of multiple layers of graphene sheets rolled into concentric cylinders. Tube diameters (3-300 nm), inner-bore diameters (2-15 nm), and lengths (nanometers - microns) are controlled to tailor physical, mechanical, and chemical properties. We proposed to explore growth and characterize nanotube arrays to help determine their exciting functionality for Sandia applications. Thermal chemical vapor deposition growth in a furnace nucleates from a metal catalyst. Ordered arrays grow using templates from self-assembled hexagonal arrays of nanopores in anodized-aluminum oxide. Polymeric-binders can mechanically hold the CNTs in place for polishing, lift-off, and membrane formation. The stiffness, electrical and thermal conductivities of CNTs make them ideally suited for a wide-variety of possible applications. Large-area, highly-accessible gas-adsorbing carbon surfaces, superb cold-cathode field-emission, and unique nanoscale geometries can lead to advanced microsensors using analyte adsorption, arrays of functionalized nanoelectrodes for enhanced electrochemical detection …
Date: November 1, 2004
Creator: Overmyer, Donald L.; Siegal, Michael P. & Yelton, William Graham
System: The UNT Digital Library
Annual Change Report 2003/2004 (open access)

Annual Change Report 2003/2004

As part of continuing compliance, the U.S. Environmental Protection Agency (EPA) requires the U.S. Department of Energy (DOE) to provide any change in information since the most recent compliance application. This requirement is identified in Title 40 Code of Federal Regulations (CFR), Section 194.4(b)(4), which states: “No later than six months after the administrator issues a certification, and at least annually thereafter, the Department shall report to the Administrator, in writing, any changes in conditions or activities pertaining to the disposal system that were not required to be reported by paragraph (b)(3) of this section and that differ from information contained in the most recent compliance application.” In meeting the requirement, the DOE provides an annual report of all changes applicable under the above requirement each November. This annual report informs the EPA of changes to information in the most recent compliance application, or for this report the 1996 Compliance Certification Application (CCA). Significant planned changes must be reported to the EPA prior to implementation by the DOE. In addition, Title 40 CFR, Section 194.4(b)(3) requires that significant unplanned changes be reported to the EPA within 24 hours or ten days, depending on the severity of the activity or condition. …
Date: November 10, 2004
Creator: Washington Regulatory and Environmental Services
System: The UNT Digital Library
Nanoporous-carbon adsorbers for chemical microsensors. (open access)

Nanoporous-carbon adsorbers for chemical microsensors.

Chemical microsensors rely on partitioning of airborne chemicals into films to collect and measure trace quantities of hazardous vapors. Polymer sensor coatings used today are typically slow to respond and difficult to apply reproducibly. The objective of this project was to produce a durable sensor coating material based on graphitic nanoporous-carbon (NPC), a new material first studied at Sandia, for collection and detection of volatile organic compounds (VOC), toxic industrial chemicals (TIC), chemical warfare agents (CWA) and nuclear processing precursors (NPP). Preliminary studies using NPC films on exploratory surface-acoustic-wave (SAW) devices and as a {micro}ChemLab membrane preconcentrator suggested that NPC may outperform existing, irreproducible coatings for SAW sensor and {micro}ChemLab preconcentrator applications. Success of this project will provide a strategic advantage to the development of a robust, manufacturable, highly-sensitive chemical microsensor for public health, industrial, and national security needs. We use pulsed-laser deposition to grow NPC films at room-temperature with negligible residual stress, and hence, can be deposited onto nearly any substrate material to any thickness. Controlled deposition yields reproducible NPC density, morphology, and porosity, without any discernable variation in surface chemistry. NPC coatings > 20 {micro}m thick with density < 5% that of graphite have been demonstrated. NPC can …
Date: November 1, 2004
Creator: Overmyer, Donald L.; Siegal, Michael P.; Staton, Alan W.; Provencio, Paula Polyak & Yelton, William Graham
System: The UNT Digital Library
Human error mitigation initiative (HEMI) : summary report. (open access)

Human error mitigation initiative (HEMI) : summary report.

Despite continuing efforts to apply existing hazard analysis methods and comply with requirements, human errors persist across the nuclear weapons complex. Due to a number of factors, current retroactive and proactive methods to understand and minimize human error are highly subjective, inconsistent in numerous dimensions, and are cumbersome to characterize as thorough. An alternative and proposed method begins with leveraging historical data to understand what the systemic issues are and where resources need to be brought to bear proactively to minimize the risk of future occurrences. An illustrative analysis was performed using existing incident databases specific to Pantex weapons operations indicating systemic issues associated with operating procedures that undergo notably less development rigor relative to other task elements such as tooling and process flow. Future recommended steps to improve the objectivity, consistency, and thoroughness of hazard analysis and mitigation were delineated.
Date: November 1, 2004
Creator: Stevens, Susan M.; Ramos, M. Victoria; Wenner, Caren A. & Brannon, Nathan Gregory
System: The UNT Digital Library
Laboratory evaluation of damage criteria and permeability of Big Hill salt. (open access)

Laboratory evaluation of damage criteria and permeability of Big Hill salt.

To establish strength criteria of Big Hill salt, a series of quasi-static triaxial compression tests have been completed. This report summarizes the test methods, set-up, relevant observations, and results. The triaxial compression tests established dilatant damage criteria for Big Hill salt in terms of stress invariants (I{sub 1} and J{sub 2}) and principal stresses ({sigma}{sub a,d} and {sigma}{sub 3}), respectively: {radical}J{sub 2}(psi) = 1746-1320.5 exp{sup -0.00034I{sub 1}(psi)}; {sigma}{sub a,d}(psi) = 2248 + 1.25 {sigma}{sub 3} (psi). For the confining pressure of 1,000 psi, the dilatant damage strength of Big Hill salt is identical to the typical salt strength ({radical}J{sub 2} = 0.27 I{sub 1}). However, for higher confining pressure, the typical strength criterion overestimates the damage strength of Big Hill salt.
Date: November 1, 2004
Creator: Ehgartner, Brian L.; Park, Byoung Yoon; Lee, Moo Yul & Bronowski, David R.
System: The UNT Digital Library
Proceedings of the 18th Annual Conference on Fossil Energy Materials. (open access)

Proceedings of the 18th Annual Conference on Fossil Energy Materials.

The 18th Annual conference on Fossil Energy Materials was held in Knoxville, Tennessee, on June 2 through June 4, 2004. The meeting was sponsored by the U.S. Department of Energy's (DOE) Office of Fossil Energy through the Advanced Research Materials Program (ARM). The objective of the ARM Program is to conduct research and development on materials for longer-term fossil energy applications, as well as for generic needs of various fossil fuel technologies. The management of the program has been decentralized to the DOE Oak Ridge Operations Office and Oak Ridge National Laboratory (ORNL). The research is performed by staff members at ORNL and by researchers at other national laboratories, universities, and in private industry. The work is divided into the following categories: (1) structural, ceramics, (2) new alloys and coatings, (3) functional materials, and (4) technology development and transfer.
Date: November 2, 2004
Creator: Judkins, RR
System: The UNT Digital Library
Equation of state and electrical conductivity of stainless steel. (open access)

Equation of state and electrical conductivity of stainless steel.

Warm dense matter is the region in phase space of density and temperature where the thermal, Fermi, and Coulomb energies are approximately equal. The lack of a dominating scale and physical behavior makes it challenging to model the physics to high fidelity. For Sandia, a fundamental understanding of the region is of importance because of the needs of our experimental HEDP programs for high fidelity descriptive and predictive modeling. We show that multi-scale simulations of macroscopic physical phenomena now have predictive capability also for difficult but ubiquitous materials such as stainless steel, a transition metal alloy.
Date: November 1, 2004
Creator: Desjarlais, Michael Paul & Mattsson, Thomas Kjell Rene
System: The UNT Digital Library
Growth and property development of convection pass deposits in recovery boilers : final project project. (open access)

Growth and property development of convection pass deposits in recovery boilers : final project project.

As part of the U.S. Department of Energy (DOE) Office of Industrial Technologies (OIT) Industries of the Future (IOF) Forest Products research program, the mechanisms of particle deposition and properties of deposits that form in the convection passes of recovery boilers were investigated. Research from experimental facilities at Sandia National Laboratories, the Institute of Paper Science and Technology (IPST), and the University of Toronto (U of T) was coordinated into a single effort to define the controlling mechanisms and rates of deposition. Deposition rates were recorded on a volumetric and mass basis in a Sandia facility for particle sizes in the range of 0.1 to 150 {micro}m. Deposit thickness, mass, spectral emissivity, thermal conductivity, surface temperature, and apparent density were monitored simultaneously and in situ on instrumented probes that allow determination of heat flux and probe surface temperature. Particle composition and mass deposition rates were also recorded in a U of T facility for particle sizes in the range of 100 to 600 {micro}m. These measurements allowed determination of the liquid content and sticking efficiency of carryover particles that inertially impact on a deposition probe. In addition, information on particulates, stable gas species, gas temperature and velocity were obtained from …
Date: November 1, 2004
Creator: Lien, Steve J. (Georgia Institute of Technology, Atlanta, GA); Baxter, Larry L.; Frederick, W. James Jr. (Georgia Institute of Technology, Atlanta, GA) & Wessel, Richard A. (Babcock & Wilcox Company, Barberton, OH)
System: The UNT Digital Library
Updates to the ORIGEN-S Cross-Section Libraries Using ENDF-VI, EAF-99, and FENDL-2.0 (open access)

Updates to the ORIGEN-S Cross-Section Libraries Using ENDF-VI, EAF-99, and FENDL-2.0

The standard cross-section library for light-water reactor (LWR) analyses used by the ORIGEN-S depletion and decay code has been extensively updated. This work entailed the development of broad multigroup neutron cross sections for ORIGEN-S from several sources of pointwise continuous-energy cross-section evaluations, including the U.S. Evaluated Nuclear Data Files ENDF/B-VI Release 7, the Fusion Evaluated Nuclear Data Library FENDL-2.0, and the European Activation File EAF-99. The pointwise cross sections were collapsed to a three-group structure using a continuous-energy neutron flux spectrum representative of the typical neutronic conditions of typical LWR fuel and formatted for use by ORIGEN-S. In addition, the fission-product library has been expanded to include ENDF/B-VI fission yield data for 30 fissionable actinides. The processing codes and procedures are explained. Preliminary verification studies using the updated libraries were performed using the modules of the SCALE (Standardized Computer Analyses for Licensing Evaluation) system. Comparisons between the previous basic ORIGEN-S libraries and the updated libraries developed in this work are presented.
Date: November 4, 2004
Creator: Murphy, B. D.
System: The UNT Digital Library
Carbon Sequestration on Surface Mine Lands (open access)

Carbon Sequestration on Surface Mine Lands

The first quarter of 2004 was dedicated to tree planting activities in two locations in Kentucky. During the first year of this project there was not available mine land to plant in the Hazard area, so 107 acres were planted in the Martin County mine location. This year 120 acres were planted in the Hazard area to compensate for the prior year and an additional 57 acres were planted on Peabody properties in western Kentucky. Additional sets of special plots were established on each of these areas that contained 4800 seedlings each for carbon sequestration demonstrations. Plantings were also conducted to continue compaction and water quality studies on the newly established areas as well as continual measurements of the first year's plantings. Total plantings on this project now amount to 357 acres containing 245,960 seedlings. During the second quarter of this year monitoring systems were established for all the new research areas. Weather data pertinent to the research as well as hydrology and water quality monitoring continues to be conducted on all areas. Studies established to assess specific questions pertaining to carbon flux and the invasion of the vegetation by small mammals are being quantified. Experimental practices initiated with this …
Date: November 30, 2004
Creator: Graves, Donald H.; Barton, Christopher; Koo, Bon Jun; Sweigard, Richard & Warner, Richard
System: The UNT Digital Library
Multi-Attribute Seismic/Rock Physics Approach to Characterizing Fractured Reservoirs (open access)

Multi-Attribute Seismic/Rock Physics Approach to Characterizing Fractured Reservoirs

Most current seismic methods to seismically characterize fractures in tight reservoirs depend on a few anisotropic wave propagation signatures that can arise from aligned fractures. While seismic anisotropy can be a powerful fracture diagnostic, a number of situations can lessen its usefulness or introduce interpretation ambiguities. Fortunately, laboratory and theoretical work in rock physics indicates that a much broader spectrum of fracture seismic signatures can occur, including a decrease in P- and S-wave velocities, a change in Poisson's ratio, an increase in velocity dispersion and wave attenuation, as well as well as indirect images of structural features that can control fracture occurrence. The goal of this project was to demonstrate a practical interpretation and integration strategy for detecting and characterizing natural fractures in rocks. The approach was to exploit as many sources of information as possible, and to use the principles of rock physics as the link among seismic, geologic, and log data. Since no single seismic attribute is a reliable fracture indicator in all situations, the focus was to develop a quantitative scheme for integrating the diverse sources of information. The integrated study incorporated three key elements: The first element was establishing prior constraints on fracture occurrence, based on …
Date: November 30, 2004
Creator: Mavko, Gary
System: The UNT Digital Library
Laser hazard analysis for LASIRIS Model MAG-501L-670M-1000-45[degree]-K diode laser associated with high resolution pulsed scanner. (open access)

Laser hazard analysis for LASIRIS Model MAG-501L-670M-1000-45[degree]-K diode laser associated with high resolution pulsed scanner.

A laser hazard analysis and safety assessment was performed for the LASIRISTM Model MAG-501L-670M-1000-45o-K diode laser associated with the High Resolution Pulse Scanner based on the ANSI Standard Z136.1-2000, American National Standard for the Safe Use of Lasers and the ANSI Standard Z136.6-2000, American National Standard for the Safe Use of Lasers Outdoors. The laser was evaluated for both indoor and outdoor use.
Date: November 1, 2004
Creator: Augustoni, Arnold L.
System: The UNT Digital Library
Modeling the transfer of land and water from agricultural to urban uses in the Middle Rio Grande Basin, New Mexico. (open access)

Modeling the transfer of land and water from agricultural to urban uses in the Middle Rio Grande Basin, New Mexico.

Social and ecological scientists emphasize that effective natural resource management depends in part on understanding the dynamic relationship between the physical and non-physical process associated with resource consumption. In this case, the physical processes include hydrological, climatological and ecological dynamics, and the non-physical process include social, economic and cultural dynamics among humans who do the resource consumption. This project represents a case study aimed at modeling coupled social and physical processes in a single decision support system. In central New Mexico, individual land use decisions over the past five decades have resulted in the gradual transformation of the Middle Rio Grande Valley from a primarily rural agricultural landscape to a largely urban one. In the arid southwestern U.S., the aggregate impact of individual decisions about land use is uniquely important to understand, because scarce hydrological resources will likely limit the viability of resulting growth and development trajectories. This decision support tool is intended to help planners in the area look forward in their efforts to create a collectively defined 'desired' social landscape in the Middle Rio Grande. Our research question explored the ways in which socio-cultural values impact decisions regarding that landscape and associated land use. Because of the constraints …
Date: November 1, 2004
Creator: Jarratt, Janet (Valencia County, NM); Passell, Howard David; Kelly, Susan (Utton Transboundary Resources Center, Albuquerque, NM); Malczynski, Leonard A.; Chermak, Janie (University of New Mexico, Albuquerque, NM); Van Bloeman Waanders, Paul (GRAM, Inc., Albuquerque, NM) et al.
System: The UNT Digital Library
Top Value Added Chemicals From Biomass: I. Results of Screening for Potential Candidates from Sugars and Synthesis Gas (open access)

Top Value Added Chemicals From Biomass: I. Results of Screening for Potential Candidates from Sugars and Synthesis Gas

This report identifies twelve building block chemicals that can be produced from sugars via biological or chemical conversions. The twelve building blocks can be subsequently converted to a number of high-value bio-based chemicals or materials. Building block chemicals, as considered for this analysis, are molecules with multiple functional groups that possess the potential to be transformed into new families of useful molecules. The twelve sugar-based building blocks are 1,4-diacids (succinic, fumaric and malic), 2,5-furan dicarboxylic acid, 3-hydroxy propionic acid, aspartic acid, glucaric acid, glutamic acid, itaconic acid, levulinic acid, 3-hydroxybutyrolactone, glycerol, sorbitol, and xylitol/arabinitol. In addition to building blocks, the report outlines the central technical barriers that are preventing the widespread use of biomass for products and chemicals.
Date: November 1, 2004
Creator: Werpy, Todd A.; Holladay, John E. & White, James F.
System: The UNT Digital Library
Multi-dimensional modeling of atmospheric copper-sulfidation corrosion on non-planar substrates. (open access)

Multi-dimensional modeling of atmospheric copper-sulfidation corrosion on non-planar substrates.

This report documents the author's efforts in the deterministic modeling of copper-sulfidation corrosion on non-planar substrates such as diodes and electrical connectors. A new framework based on Goma was developed for multi-dimensional modeling of atmospheric copper-sulfidation corrosion on non-planar substrates. In this framework, the moving sulfidation front is explicitly tracked by treating the finite-element mesh as a pseudo solid with an arbitrary Lagrangian-Eulerian formulation and repeatedly performing re-meshing using CUBIT and re-mapping using MAPVAR. Three one-dimensional studies were performed for verifying the framework in asymptotic regimes. Limited model validation was also carried out by comparing computed copper-sulfide thickness with experimental data. The framework was first demonstrated in modeling one-dimensional copper sulfidation with charge separation. It was found that both the thickness of the space-charge layers and the electrical potential at the sulfidation surface decrease rapidly as the Cu{sub 2}S layer thickens initially but eventually reach equilibrium values as Cu{sub 2}S layer becomes sufficiently thick; it was also found that electroneutrality is a reasonable approximation and that the electro-migration flux may be estimated by using the equilibrium potential difference between the sulfidation and annihilation surfaces when the Cu{sub 2}S layer is sufficiently thick. The framework was then employed to model copper …
Date: November 1, 2004
Creator: Chen, Ken Shuang
System: The UNT Digital Library
Microfabrication with femtosecond laser processing : (A) laser ablation of ferrous alloys, (B) direct-write embedded optical waveguides and integrated optics in bulk glasses. (open access)

Microfabrication with femtosecond laser processing : (A) laser ablation of ferrous alloys, (B) direct-write embedded optical waveguides and integrated optics in bulk glasses.

At Sandia National Laboratories, miniaturization dominates future hardware designs, and technologies that address the manufacture of micro-scale to nano-scale features are in demand. Currently, Sandia is developing technologies such as photolithography/etching (e.g. silicon MEMS), LIGA, micro-electro-discharge machining (micro-EDM), and focused ion beam (FIB) machining to fulfill some of the component design requirements. Some processes are more encompassing than others, but each process has its niche, where all performance characteristics cannot be met by one technology. For example, micro-EDM creates highly accurate micro-scale features but the choice of materials is limited to conductive materials. With silicon-based MEMS technology, highly accurate nano-scale integrated devices are fabricated but the mechanical performance may not meet the requirements. Femtosecond laser processing has the potential to fulfill a broad range of design demands, both in terms of feature resolution and material choices, thereby improving fabrication of micro-components. One of the unique features of femtosecond lasers is the ability to ablate nearly all materials with little heat transfer, and therefore melting or damage, to the surrounding material, resulting in highly accurate micro-scale features. Another unique aspect to femtosecond radiation is the ability to create localized structural changes thought nonlinear absorption processes. By scanning the focal point within …
Date: November 1, 2004
Creator: Guo, Junpeng; McDaniel, Karen Lynn; Palmer, Jeremy Andrew; Yang, Pin; Griffith, Michelle Lynn; Vawter, Gregory Allen et al.
System: The UNT Digital Library
Precision volume measurement system. (open access)

Precision volume measurement system.

A new precision volume measurement system based on a Kansas City Plant (KCP) design was built to support the volume measurement needs of the Gas Transfer Systems (GTS) department at Sandia National Labs (SNL) in California. An engineering study was undertaken to verify or refute KCP's claims of 0.5% accuracy. The study assesses the accuracy and precision of the system. The system uses the ideal gas law and precise pressure measurements (of low-pressure helium) in a temperature and computer controlled environment to ratio a known volume to an unknown volume.
Date: November 1, 2004
Creator: Fischer, Erin E. & Shugard, Andrew D.
System: The UNT Digital Library
Genetic Augmentation of Syringyl Lignin in Low-lignin Aspen Trees, Final Report (open access)

Genetic Augmentation of Syringyl Lignin in Low-lignin Aspen Trees, Final Report

As a polysaccharide-encrusting component, lignin is critical to cell wall integrity and plant growth but also hinders recovery of cellulose fibers during the wood pulping process. To improve pulping efficiency, it is highly desirable to genetically modify lignin content and/or structure in pulpwood species to maximize pulp yields with minimal energy consumption and environmental impact. This project aimed to genetically augment the syringyl-to-guaiacyl lignin ratio in low-lignin transgenic aspen in order to produce trees with reduced lignin content, more reactive lignin structures and increased cellulose content. Transgenic aspen trees with reduced lignin content have already been achieved, prior to the start of this project, by antisense downregulation of a 4-coumarate:coenzyme A ligase gene (Hu et al., 1999 Nature Biotechnol 17: 808- 812). The primary objective of this study was to genetically augment syringyl lignin biosynthesis in these low-lignin trees in order to enhance lignin reactivity during chemical pulping. To accomplish this, both aspen and sweetgum genes encoding coniferaldehyde 5-hydroxylase (Osakabe et al., 1999 PNAS 96: 8955-8960) were targeted for over-expression in wildtype or low-lignin aspen under control of either a constitutive or a xylem-specific promoter. A second objective for this project was to develop reliable and cost-effective methods, such as …
Date: November 10, 2004
Creator: Tsai, Chung-Jui; Davis, Mark F. & Chiang, Vincent L.
System: The UNT Digital Library