MECHANICAL RESPONSE OF STITCHED T300 MAT/URETHANE 420 IMR COMPOSITE LAMINATES: PROPERTY/ORIENTATION DEPENDENCE AND DAMAGE EVOLUTION (open access)

MECHANICAL RESPONSE OF STITCHED T300 MAT/URETHANE 420 IMR COMPOSITE LAMINATES: PROPERTY/ORIENTATION DEPENDENCE AND DAMAGE EVOLUTION

None
Date: May 4, 2000
Creator: Deng, S.
Object Type: Report
System: The UNT Digital Library
Multiple quantum and dipolar correlation effect NMR studies of cross-linking in elastomer systems (open access)

Multiple quantum and dipolar correlation effect NMR studies of cross-linking in elastomer systems

None
Date: October 4, 2000
Creator: Maxwell, R S & Balazs, B
Object Type: Article
System: The UNT Digital Library
Hydride precipitation crack propagation in zircaloy cladding during a decreasing temperature history (open access)

Hydride precipitation crack propagation in zircaloy cladding during a decreasing temperature history

An assessment of safety, design, and cost tradeoff issues for short (ten to fifty years) and longer (fifty to hundreds of years) interim dry storage of spent nuclear fuel in Zircaloy rods shall address potential failures of the Zircaloy cladding caused by the precipitation response of zirconium hydride platelets. If such assessment analyses are to be done rigorously, they will be necessarily complex because the precipitation response of zirconium hydride platelets is a stochastic functional of hydrogen concentration, temperature, stress, fabrication defect/texture structures, and flaw sizes of the cladding. Thus, there are, and probably always will be, zirhydride questions to analytically and experimentally resolve concerning the consistency, the completeness, and the certainty of models, data, the initial and the time-dependent boundary conditions. Some resolution of these questions will be required in order to have a defensible preference and tradeoffs decision analysis for assessing risks and consequences of the potential zirhydride induced cladding failures during dry storage time intervals. In the following brief discussion, one of these questions is posed as a consequence of an anomaly described in data reproducibility that was reported in the results of tests for hydrogen induced delayed cracking. The testing anomaly consisted of observing a significant …
Date: December 4, 2000
Creator: Stout, R B
Object Type: Article
System: The UNT Digital Library
AZU-1: A Candidate Breast Tumor Suppressor and Biomarker for Tumor Progression (open access)

AZU-1: A Candidate Breast Tumor Suppressor and Biomarker for Tumor Progression

To identify genes misregulated in the final stages of breast carcinogenesis, we performed differential display to compare the gene expression patterns of the human tumorigenic mammary epithelial cells, HMT-3522-T4-2, with those of their immediate premalignant progenitors, HMT-3522-S2. We identified a novel gene, called anti-zuai-1 (AZU-1), that was abundantly expressed in non- and premalignant cells and tissues but was appreciably reduced in breast tumor cell types and in primary tumors. The AZU-1 gene encodes an acidic 571-amino-acid protein containing at least two structurally distinct domains with potential protein-binding functions: an N-terminal serine and proline-rich domain with a predicted immunoglobulin-like fold and a C-terminal coiled-coil domain. In HMT-3522 cells, the bulk of AZU-1 protein resided in a detergent-extractable cytoplasmic pool and was present at much lower levels in tumorigenic T4-2 cells than in their nonmalignant counterparts. Reversion of the tumorigenic phenotype of T4-2 cells, by means described previously, was accompanied by the up-regulation of AZU-1. In addition, reexpression of AZU-1 in T4-2 cells, using viral vectors, was sufficient to reduce their malignant phenotype substantially, both in culture and in vivo. These results indicate that AZU-1 is a candidate breast tumor suppressor that may exert its effects by promoting correct tissue morphogenesis.
Date: February 4, 2000
Creator: Chen, Huei-Mei; Schmeichel, Karen L; Mian, I. Saira; Lelie`vre, Sophie; Petersen, Ole W & Bissell, Mina J
Object Type: Article
System: The UNT Digital Library
Groundwater Quality Assessment for Waste Management Area U: First Determination (open access)

Groundwater Quality Assessment for Waste Management Area U: First Determination

As a result of the most recent recalculation one of the indicator parameters, specific conductance, exceeded its background value in downgradient well 299-W19-41, triggering a change from detection monitoring to groundwater quality assessment program. The major contributors to the higher specific conductance are nonhazardous constituents (i.e., sodium, calcium, magnesium, chloride, sulfate, and bicarbonate). Nitrate, chromium, and technetium-99 are present and are increasing; however, they are significantly below their drinking waster standards. Interpretation of groundwater monitoring data indicates that both the nonhazardous constituents causing elevated specific conductance in groundwater and the tank waste constituents present in groundwater at the waste management area are a result of surface water infiltration in the southern portion of the facility. There is evidence for both upgradient and waste management area sources for observed nitrate concentrations. There is no indication of an upgradient source for the observed chromium and technetium-99.
Date: August 4, 2000
Creator: Hodges, Floyd N. & Chou, Charissa J.
Object Type: Report
System: The UNT Digital Library
Economic Energy Savings Potential in Federal Buildings (open access)

Economic Energy Savings Potential in Federal Buildings

The primary objective of this study was to estimate the current life-cycle cost-effective (i.e., economic) energy savings potential in Federal buildings and the corresponding capital investment required to achieve these savings, with Federal financing. Estimates were developed for major categories of energy efficiency measures such as building envelope, heating system, cooling system, and lighting. The analysis was based on conditions (building stock and characteristics, retrofit technologies, interest rates, energy prices, etc.) existing in the late 1990s. The potential impact of changes to any of these factors in the future was not considered.
Date: September 4, 2000
Creator: Brown, Daryl R.; Dirks, James A. & Hunt, Diane M.
Object Type: Report
System: The UNT Digital Library
Groundwater Flow and Transport Calculations Supporting the Immobilized Low-Activity Waste Disposal Facility Performance Assessment (open access)

Groundwater Flow and Transport Calculations Supporting the Immobilized Low-Activity Waste Disposal Facility Performance Assessment

This report summarizes the Hanford Site-Wide Groundwater Model and its application to the Immobilized Low-Activity Waste (ILAW) Disposal Facility Performance Assessment (PA). The site-wide model and supporting local-scale models are used to evaluate impacts from the transport of contaminants at a hypothetical well 100 m downgradient of the disposal facilities and to evaluate regional flow conditions and transport from the ILAW disposal facilities to the Columbia River. These models were used to well-intercept factors (WIFs) or dilution factors from a given areal flux of a hypothetical contaminant released to the unconfined aquifer from the ILAW disposal facilities for two waste-disposal options: 1) a remote-handled trench concept and 2) a concrete-vault concept. The WIF is defined as the ratio of the concentration at a well location in the aquifer to the concentration of infiltrating water entering the aquifer. These WIFs are being used in conjunction with calculations of released contaminant fluxes through the vadose zone to estimate potential impacts from radiological and hazardous chemical contaminants within the ILAW disposal facility at compliance points.
Date: December 4, 2000
Creator: Bergeron, Marcel P. & Wurstner, Signe K.
Object Type: Report
System: The UNT Digital Library
Improving DOE-2's RESYS routine: User defined functions to provide more accurate part load energy use and humidity predictions (open access)

Improving DOE-2's RESYS routine: User defined functions to provide more accurate part load energy use and humidity predictions

In hourly energy simulations, it is important to properly predict the performance of air conditioning systems over a range of full and part load operating conditions. An important component of these calculations is to properly consider the performance of the cycling air conditioner and how it interacts with the building. This paper presents improved approaches to properly account for the part load performance of residential and light commercial air conditioning systems in DOE-2. First, more accurate correlations are given to predict the degradation of system efficiency at part load conditions. In addition, a user-defined function for RESYS is developed that provides improved predictions of air conditioner sensible and latent capacity at part load conditions. The user function also provides more accurate predictions of space humidity by adding ''lumped'' moisture capacitance into the calculations. The improved cooling coil model and the addition of moisture capacitance predicts humidity swings that are more representative of the performance observed in real buildings.
Date: August 4, 2000
Creator: Henderson, Hugh I.; Parker, Danny & Huang, Yu J.
Object Type: Article
System: The UNT Digital Library
Stress Corrosion Crack Growth Rate Testing and Analytical Electron Microscopy of Alloy 600 as a Function of Pourbaix Space and Microstructure (open access)

Stress Corrosion Crack Growth Rate Testing and Analytical Electron Microscopy of Alloy 600 as a Function of Pourbaix Space and Microstructure

Stress corrosion crack (SCC) growth rate tests and analytical electron microscopy (AEM) studies were performed over a broad range of environments and heat treatments of Alloy 600. This effort was conducted to correlate bulk environmental conditions such as pH and electrochemical potential (EcP) with the morphology of the SCC crack. Development of a library of AEM morphologies formed by SCC in different environments is an important step in identifying the conditions that lead to SCC in components. Additionally, AEM examination of stress corrosion cracks formed in different environments and microstructures lends insight into the mechanism(s) of stress corrosion cracking. Testing was conducted on compact tension specimens in three environments: a mildly acidic oxidizing environment containing sulfate ions, a caustic environment containing 10% NaOH, and hydrogenated near-neutral buffered water. Additionally, stress corrosion cracking testing of a smooth specimen was conducted in hydrogenated steam. The following heat treatments of Alloy 600 were examined: mill annealed at 980 C (near-neutral water), mill annealed at 1010 C (steam), sensitized (acid and caustic), and mill annealed + healed to homogenize the grain boundary Cr concentration (caustic). Crack growth rate (CGR) testing showed that sensitized Alloy 600 tested in the mildly acidic, oxidizing environment containing sulfate …
Date: October 4, 2000
Creator: Lewis, N.; Attanasio, S. A.; Morton, D. S. & Young, G. A.
Object Type: Report
System: The UNT Digital Library
A genetic approach to improved semi-solid forming of metals. Final report for period September 4, 1999 - March 4, 2000 (open access)

A genetic approach to improved semi-solid forming of metals. Final report for period September 4, 1999 - March 4, 2000

Lack of technology for the production of large inexpensive feedstock, with uniform spherical primary phase throughout as required for semi-solid forming, has restricted realization of the full potential for the semi-solid forming process. Furthermore narrow process windows and alloy chemistry restrictions increase process costs and limit performance attributes possible with existing semi-metal systems. Successful semi-solid forming trials utilizing Chesapeake Composites Corporation's DSC{sup TM} Metals for feedstock indicate that this represents a generic approach to providing a permanent highly uniform, spherical solid phase, without electromagnetic or mechanical shearing. This approach also provides for further growth of semi-solid forming by providing for: low cost large diameter billet stock, reduced semi-solid forming costs, extension of semi-solid forming to new alloy systems, and semi-solid formed components with substantially enhanced physical and mechanical properties.
Date: May 4, 2000
Creator: Klier, Eric M.
Object Type: Report
System: The UNT Digital Library
Dynamic and Thermodynamic Behavior of Carboneous and Hydrogen-Bonding Materials (open access)

Dynamic and Thermodynamic Behavior of Carboneous and Hydrogen-Bonding Materials

Dissociation behavior of carboneous materials with or without fluorine atoms at pressures (P) of tens of gigapascal (GPa) and temperature (T) at several thousand Kelvin is not so well understood. The main issues are: (a) carbon condensation processes and (b) thermodynamics of hydrogen fluoride (HF) produced from dissociation. Item (a) requires information on (i) the melting line of carbon, (ii) liquid carbon, (iii) stability and energy barrier between graphite and diamond clusters, and (iv) kinetics of cluster growth. Item (b) requires knowledge of (v) intermolecular potentials involving HF and (vi) influence of fluorine chemistry on supercritical phase change. The details concerning these issues are described.
Date: February 4, 2000
Creator: Ree, F. H.; Galli, G.; Glosli, J. N.; Gygi, F.; Schwegler, E.; Viecelli, J. A. et al.
Object Type: Article
System: The UNT Digital Library
Definition and Means of Maintaining the Emergency Notification and Evacuation System Portion of the Plutonium Finishing Plant (PFP) Safety Envelope (open access)

Definition and Means of Maintaining the Emergency Notification and Evacuation System Portion of the Plutonium Finishing Plant (PFP) Safety Envelope

The purpose of this document is to provide the definition and means of maintaining the safety envelope (SE) for the Emergency Notification and Evacuation System (ENES). Together with the appendices, it provides: (1) The system requirements for determining system operability (Section 3.0); (2) Evaluations of equipment to determine the safety boundary for the system (Section 4.0); (3) List of system drawings that are annotated to show the SE boundaries (Appendix A); (4) Identification of the SE equipment by reference to systems and drawings (Appendix B); (5) Requirements for the individual SE equipment (Section 4.0); and (6) A list of the operational and surveillance procedures necessary to operate and maintain the system equipment within the SE (Sections 5.0 and 6.0). The Private Automatic Exchange (PAX) phones and PAX switchers are outside the safety envelope defined in WHC-SD-CP-OSR-010, Section 5.4.10, ''Safety Communication and Alarm Systems,'' Section 5.4.1 0.1, ''Major Components and Operating Characteristics,'' and Section 5.4.10.1.12, ''PAX System.'' The PAX override microphone system maintains the safety envelope, and functions as a backup to the evacuation sirens during an emergency.
Date: April 4, 2000
Creator: WHITE, W.F.
Object Type: Report
System: The UNT Digital Library
Cold Vacuum Drying (CVD) Set Point Determination (open access)

Cold Vacuum Drying (CVD) Set Point Determination

The Safety Class Instrumentation and Control (SCIC) system provides active detection and response to process anomalies that, if unmitigated, would result in a safety event. Specifically, actuation of the SCIC system includes two portions. The portion which isolates the MCO and initiates the safety-class helium (SCHe) purge, and the portion which detects and stops excessive heat input to the MCO annulus on high Tempered Water (TW) inlet temperature. For the MCO isolation and purge, the SCIC receives MCO pressure (both positive pressure and vacuum), helium flow rate, bay high temperature switch status, seismic trip status, and time-under-vacuum trips signals. The SCIC system will isolate the MCO and start an SCHe system purge if any of the following occur. (1) Isolation and purge from one of the SCHe ''isolation'' and ''purge'' buttons is manually initiated (administratively controlled). (2) The first vacuum cycle exceeds 8 hours at vacuum, or any subsequent vacuum cycle exceeds 4 hours at vacuum without re-pressurizing the MCO for a minimum of 4 hours. (This is referred to as the 8/4/4 requirement and provides thermal equilibrium within the MCO.) (3) MCO is below atmospheric pressure and the helium flow is below the minimum required to keep hydrogen less …
Date: September 4, 2000
Creator: PHILIPP, B.L.
Object Type: Report
System: The UNT Digital Library
Honeywell Modular Automation System Computer Software Documentation (open access)

Honeywell Modular Automation System Computer Software Documentation

The purpose of this Computer Software Document (CSWD) is to provide configuration control of the Honeywell Modular Automation System (MAS) in use at the Plutonium Finishing Plant (PFP). This CSWD describes hardware and PFP developed software for control of stabilization furnaces. The Honeywell software can generate configuration reports for the developed control software. These reports are described in the following section and are attached as addendum's. This plan applies to PFP Engineering Manager, Thermal Stabilization Cognizant Engineers, and the Shift Technical Advisors responsible for the Honeywell MAS software/hardware and administration of the Honeywell System.
Date: December 4, 2000
Creator: STUBBS, A.M.
Object Type: Report
System: The UNT Digital Library
Waste Handling Practices for the Plutonium Immobilization Plant (open access)

Waste Handling Practices for the Plutonium Immobilization Plant

Solid waste handling operations refers to all activities associated with the segregation, collection, packaging, assay, storage, and removal of solid radioactive waste from radiological facilities. The Plutonium Immobilization Plant (PIP) is expected to generate the following types of radiological waste, as defined in WSRC Manual 1S, ''Waste Acceptance Criteria'': Low level waste; Mixed hazardous waste; TRU waste; and Mixed TRU waste. Historically, waste handling activities have been demanding proportionately larger amounts of labor, time, and space to effectively manage waste in accordance with increasing regulatory requirements. Since the PIP will be designed for an annual throughput of five metric tonnes plutonium, the facility waste handling operations can be expected to have at least twice the impact of such operations at existing facilities.
Date: August 4, 2000
Creator: Severynse, T.F.
Object Type: Report
System: The UNT Digital Library
Synchrotron-Based Experimental Investigations and Numerical Modeling of the Kinetics of Phase Transformations in the Heat Affected Zone of Welds (open access)

Synchrotron-Based Experimental Investigations and Numerical Modeling of the Kinetics of Phase Transformations in the Heat Affected Zone of Welds

Spatially Resolved X-Ray Diffraction (SRXRD) and Time Resolved X-Ray Diffraction (TRXRD) methods are being developed at LLNL for in-situ investigations of phase transformations in the heat-affected zone (HAZ) of welds. In this region of the weld, severe temperature gradients, high peak temperatures and rapid thermal fluctuations occur as the heat source passes through the material. These non-isothermal temperature fluctuations produce HAZ microstructures that cannot be predicted by conventional methods. The unique synchrotron-based experiments being developed here will enable the determination of phase transformation kinetics under true non-isothermal welding conditions, and can be used to aid in the development of models to predict HAZ microstructural evolution under a wide range of welding conditions. Commercially pure titanium, stainless steel alloys and plain carbon steels are currently under investigation.
Date: May 4, 2000
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Role of the Rubisco small subunit. Final report for period May 1, 1997--April 30,2000 (open access)

Role of the Rubisco small subunit. Final report for period May 1, 1997--April 30,2000

CO{sub 2} and O{sub 2} are mutually competitive at the active site of ribulose-1,5-biphosphate (RuBP) carboxylase/oxygenase (Rubisco). Rubisco contains two subunits, each present in eight copies. The 15-kD small subunit is coded by a family of nuclear RbcS genes. Until now, the role of the small subunit in Rubisco structure or catalytic efficiency is not known. Because of other work in eliminating the two RbcS genes in the green algo Chlamydomonas reinhardtii, it is now possible to address questions about the structure-function relationships of the eukaryotic small subunit. There are three specific aims in this project: (1) Alanine scanning mutagenesis is being used to dissect the importance of the {beta}A/{beta}B loop, a feature unique to the eukaryotic small subunit. (2) Random mutagenesis is being used to identify additional residues or regions of the small subunit that are important for holoenzyme assembly and function. (3) Attempts are being made to express foreign small subunits in Chlamydomonas to examine the contribution of small subunits to holoenzyme assembly, catalytic efficiency, and CO{sub 2}/O{sub 2} specificity.
Date: October 4, 2000
Creator: Spreitzer, Robert J.
Object Type: Report
System: The UNT Digital Library
Preparation of Phased and Merged Safety Analysis Reports for New DOE Nuclear Facilities (open access)

Preparation of Phased and Merged Safety Analysis Reports for New DOE Nuclear Facilities

The Spent Nuclear Fuels Project (SNFP) is charged with moving to storage 2,100 metric tons of spent nuclear fuel elements left over from plutonium production at DOE'S Hanford site in Washington state. Two new facilities, the Cold Vacuum Drying Facility (CVDF) and the Canister Storage Building (CSB) are in final construction. In order to meet aggressive schedule commitments, the SNFP chose to prepare the safety analysis reports (SAR's) in phases that covered only specific portions of each facility's design as it was built. Each SAR also merged the preliminary and final safety analysis reports into a single SAR, thereby covering all aspects of design, construction, and operation for that portion (phase) of the facility. A policy of ''NRC equivalency'' was also implemented in parallel with this effort, with the goal of achieving a rigor of safety analysis equivalent to that of NRC-licensed fuel processing facilities. DOE Order 5480.23. ''Nuclear Safety Analysis Reports'' allows preparation of both a phased and a merged SAR to accelerate construction schedules. However, project managers must be aware that such acceleration is not guaranteed. Managers considering this approach for their project should be cognizant of numerous obstacles that will be encountered. Merging and phasing SAR's will …
Date: April 4, 2000
Creator: Bishop, G. E.
Object Type: Report
System: The UNT Digital Library
Conceptual design of a compact positron tomograph for prostateimaging (open access)

Conceptual design of a compact positron tomograph for prostateimaging

We present a conceptual design of a compact positron tomograph for prostate imaging using a pair of external curved detector banks, one placed above and one below the patient. The lower detector bank is fixed below the patient bed, and the top bank adjusts vertically for maximum sensitivity and patient access. Each bank is composed of 40conventional block detectors, forming two arcs (44 cm minor, 60 cm major axis) that are tilted to minimize attenuation and positioned as close as possible to the patient to improve sensitivity. The individual detectors are angled to point towards the prostate to minimize resolution degradation in that region. Inter-plane septa extend 5 cm beyond the scintillator crystals to reduce random and scatter backgrounds. A patient is not fully encircled by detector rings in order to minimize cost,causing incomplete sampling due to the side gaps. Monte Carlo simulation (including random and scatter) demonstrates the feasibility of detecting a spherical tumor of 2.5 cm diameter with a tumor to background ratio of2:1, utilizing the number of events that should be achievable with a6-minute scan after a 10 mCi injection (e.g., carbon-11 choline or fluorine-18 fluorocholine).
Date: November 4, 2000
Creator: Huber, J. S.; Derenzo, S. E.; Qi, J.; Moses, W. W.; Huesman, R. H. & Budinger, T. F.
Object Type: Article
System: The UNT Digital Library
Evaluation of Proposed New LLW Disposal Activity Disposal of Compacted Job Control Waste, Non-compactible, Non-incinerable Waste, And Other Wasteforms In Slit Trenches (open access)

Evaluation of Proposed New LLW Disposal Activity Disposal of Compacted Job Control Waste, Non-compactible, Non-incinerable Waste, And Other Wasteforms In Slit Trenches

The effect of trench disposal of low-level wasteforms that were not analyzed in the original performance assessment for the E-Area low-level waste facility, but were analyzed in the revised performance assessment is evaluated. This evaluation was conducted to provide a bridge from the current waste acceptance criteria, which are based on the original performance assessment, to those that will be developed from the revised performance assessment. The conclusion of the evaluation is that any waste except for materials that would retain radionuclides more strongly than soil that meets the radionuclide concentration of package limits for trench burial based on the revised performance assessment, and presented in Table 1 of this document, is suitable for trench disposal; provided that, for cellulosic material the current 40 percent restriction is retained. Table 2 of this document lists materials acceptable for trench disposal.
Date: May 4, 2000
Creator: WILHITE, ELMERL.
Object Type: Report
System: The UNT Digital Library
A joint U.S.-China demonstration energy efficient office building (open access)

A joint U.S.-China demonstration energy efficient office building

In July 1998, USDOE and China's Ministry of Science and Technology (MOST) signed a Statement of Work to develop a demonstration energy-efficient office building and demonstration center in Beijing that will eventually house the Administrative Center for China's Agenda 21 (ACCA21). The statement calls for the Chinese side to be responsible for the basic construction of the 13,000 m{sup 2} 9-story building, the US side for technical assistance and the incremental costs of the energy efficiency improvements, and the joint establishment of a Demonstration Center to provide outreach and exhibit energy-efficient building technologies. The US technical team made several trips to China to meet with ACCA21 and the design team, and used the DOE-2.1E simulation program to analyze the energy performance of a preliminary building design and study alternative designs and energy-efficient strategies. A feasibility study completed in September found the largest and most cost-effective savings potentials in reducing cooling and lighting energy use, and identified eight generic measures in lighting, windows, daylighting, and HVAC systems and controls. Following these and other recommendations from the US team, the design team produced a schematic cross-shaped building design that, based on the DOE-2 analysis, lowered total energy use by 40% compared to …
Date: August 4, 2000
Creator: Zimmerman, Mary Beth; Huang, Yu JoeWatson, Rob; Shi, Han; Judkoff, Ron & She rman, Micah
Object Type: Article
System: The UNT Digital Library
STEW: A Nonlinear Data Modeling Computer Program (open access)

STEW: A Nonlinear Data Modeling Computer Program

A nonlinear data modeling computer program, STEW, employing the Levenberg-Marquardt algorithm, has been developed to model the experimental {sup 239}Pu(n,f) and {sup 235}U(n,f) cross sections. This report presents results of the modeling of the {sup 239}Pu(n,f) and {sup 235}U(n,f) cross-section data. The calculation of the fission transmission coefficient is based on the double-humped-fission-barrier model of Bjornholm and Lynn. Incident neutron energies of up to 5 MeV are considered.
Date: March 4, 2000
Creator: Chen, H.
Object Type: Report
System: The UNT Digital Library
PFP Public Automatic Exchange (PAX) Commercial Grade Item (CGI) Critical Characteristics (open access)

PFP Public Automatic Exchange (PAX) Commercial Grade Item (CGI) Critical Characteristics

This document specifies the critical characteristics for Commercial Grade Items (CGI) procured for use within the safety envelope of PFP's PAX system as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that the equipment must meet in order to properly perform its safety function. There may be several manufacturers or models that meet the critical characteristics for any one item.
Date: April 4, 2000
Creator: White, W. F.
Object Type: Report
System: The UNT Digital Library
Final Report for High Precision Short-Pulse Laser Ablation System for Medical Applications (open access)

Final Report for High Precision Short-Pulse Laser Ablation System for Medical Applications

During the three year LDRD funding period, we studied the ablation characteristics of biological tissues using ultrashort pulse lasers (USPL) with pulse widths varying from 100 femtoseconds to tens of picoseconds. During the first year, we performed extensive theoretical studies to develop an improved understanding of the USPL ablation process. Two optical signals were tested for feasibility of use in real-time feedback systems during high repetition rate ablation. In the second year, we devised a real-time, feedback-controlled USPL ablation system, based on luminescence, which may be useful for sensitive micro-spinal surgeries. Effective laser parameters were identified to reduce collateral damage. The final year of the project focused on quantification of the pressure pulse induced by USPL ablation of water surfaces representing biological tissues. Results of these studies were presented in invited talks at domestic and international conferences and numerous journal articles were published (see bibliography). This effort has increased our scientific understanding of physical processes important for the therapeutic biomedical application of ultrashort pulse lasers, and has taken the first steps toward practical realization of such applications.
Date: March 4, 2000
Creator: Kim, B. M.; Feit, M.; Rubenchik, A. & Marion, J.
Object Type: Report
System: The UNT Digital Library