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Tax Shelters: Services Provided by External Auditors (open access)

Tax Shelters: Services Provided by External Auditors

A letter report issued by the Government Accountability Office with an abstract that begins "Recent legislative and regulatory changes have addressed the relationship between auditor-provided tax services and auditor independence. At this time, the federal regulatory community is exploring further changes. To contribute to the discussion surrounding these changes, GAO's objectives were to determine (1) according to Internal Revenue Service (IRS) data, how many Fortune 500 companies obtained tax shelter services from their auditor; (2) according to IRS data, in how many Fortune 500 companies did the auditor provide the services to individual company officers or directors; and (3) whether selected Fortune 500 case study companies changed how they obtain tax services from their auditor in recent years. For the first two objectives, GAO used IRS and Standard and Poor's data after finding they were sufficiently reliable for our work. GAO counted a company, officer, or director as obtaining a tax shelter service from the company's external auditor when an auditor that IRS identified as promoting a tax shelter also audited the company in at least one year that the shelter was in effect. For the third objective, independent of any IRS information, GAO selected case studies on the basis …
Date: February 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Immigrant Investors: Small Number of Participants Attributed to Pending Regulations and Other Factors (open access)

Immigrant Investors: Small Number of Participants Attributed to Pending Regulations and Other Factors

A letter report issued by the Government Accountability Office with an abstract that begins "In 1990, Congress established an investor visa category, referred to as EB-5, whereby immigrants are granted conditional residence and after 2 years, permanent residence status in the United States if they invest in a commercial enterprise that will benefit the U.S. economy and create at least 10 full-time jobs. The Basic Pilot Program Extension and Expansion Act of 2003 (P.L. 108-156) mandates that GAO provide certain information regarding the EB-5 employment category. In response to the mandate, this report provides information on immigrant participation, including the number of participants, their countries of origin, and the number who sought U.S. citizenship. Also, this report includes information about the types of business established and where they were established."
Date: April 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Military Bases: Analysis of DOD's 2005 Selection Process and Recommendations for Base Closures and Realignments (open access)

Military Bases: Analysis of DOD's 2005 Selection Process and Recommendations for Base Closures and Realignments

A letter report issued by the Government Accountability Office with an abstract that begins "On May 13, 2005, the Secretary of Defense submitted proposed base realignment and closure (BRAC) actions to an independent commission for its review. The Commission must submit its recommendations to the President by September 8, 2005, for his acceptance or rejection in their entirety. Congress has final action to accept or reject these recommendations in their entirety later this year. The law requires that GAO issue a report on the Department of Defense's (DOD) recommendations and selection process by July 1, 2005. GAO's objectives were to (1) determine the extent to which DOD's proposals achieved its stated BRAC goals, (2) analyze whether the process for developing recommendations was logical and reasoned, and (3) identify issues with the recommendations that may warrant further attention. Time constraints limited GAO's ability to examine implementation details of most of the individual recommended actions."
Date: July 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Social Security Statements: Social Security Administration Should Better Evaluate Whether Workers Understand Their Statements (open access)

Social Security Statements: Social Security Administration Should Better Evaluate Whether Workers Understand Their Statements

A letter report issued by the Government Accountability Office with an abstract that begins "The Social Security Statement is the federal government's main document for communicating with more than 140 million workers about their Social Security benefits. By law, the statement must show an individual's annual earnings, payments into Social Security and Medicare, and projected benefits. The Social Security Administration also uses the statement to explain the various types of Social Security benefits and to encourage greater financial planning for retirement. GAO conducted a review to examine (1) how well recipients understand the current statement, (2) how the Social Security Administration is evaluating the statement's understandability, and (3) the promising practices used by private sector companies and other industrial countries. GAO's information was obtained from its national survey and focus groups of statement recipients, a firm that evaluates benefit statements, officials from three other countries (Canada, Sweden, and the United Kingdom), and other experts from the private sector."
Date: April 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Defense Acquisitions: Plans Need to Allow Enough Time to Demonstrate Capability of First Littoral Combat Ships (open access)

Defense Acquisitions: Plans Need to Allow Enough Time to Demonstrate Capability of First Littoral Combat Ships

A letter report issued by the Government Accountability Office with an abstract that begins "To conduct operations in littorals--shallow coastal waters--the Navy plans to build a new class of surface warship: the Littoral Combat Ship (LCS). LCS is being designed to accomplish its missions through systems operating at a distance from the ship, such as helicopters and unmanned vehicles, and that will be contained in interchangeable mission packages. The Navy is using an accelerated approach to buy the LCS, building the ships in "flights." Flight 0, consisting of four ships, will provide limited capability and test the LCS concept. The schedule allows 12 months between the delivery of the first Flight 0 ship and the start of detailed design and construction for Flight 1 ships. Estimated procurement cost of the Flight 0 ships is $1.5 billion. The Congress directed GAO to review the LCS program. This report assesses the analytical basis of LCS requirements; the Navy's progress in defining the concept of operations; the technical maturity of the mission packages; and the basis of recurring costs for LCS."
Date: March 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Military Personnel: DOD Needs to Conduct a Data-Driven Analysis of Active Military Personnel Levels Required to Implement the Defense Strategy (open access)

Military Personnel: DOD Needs to Conduct a Data-Driven Analysis of Active Military Personnel Levels Required to Implement the Defense Strategy

A letter report issued by the Government Accountability Office with an abstract that begins "Congress recently increased active military personnel levels for the Army and the Marine Corps. The Secretary of Defense has undertaken initiatives to use military personnel more efficiently such as rebalancing high-demand skills between active and reserve components. In view of concerns about active personnel, GAO reviewed the ways in which the Department of Defense (DOD) determines personnel requirements and is managing initiatives to assign a greater proportion of active personnel to warfigthing duties. GAO assessed the extent to which the Office of the Secretary of Defense (OSD) (1) has conducted a data-based analysis of active military personnel needed to implement the national defense strategy and (2) has a plan for making more efficient use of active military personnel and evaluating the plan's results."
Date: February 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Financial Audit: American Battle Monuments Commission's Financial Statements for Fiscal Year 2004 and 2003 (open access)

Financial Audit: American Battle Monuments Commission's Financial Statements for Fiscal Year 2004 and 2003

A letter report issued by the Government Accountability Office with an abstract that begins "In accordance with 36 U.S.C. 2103, GAO is responsible for conducting audits of the agencywide financial statements of the American Battle Monuments Commission (the Commission). GAO audited the financial statements of the Commission for the fiscal years ended September 30, 2004, and 2003. The audits were done to determine whether, in all material respects, (1) the Commission's financial statements were reliable, and (2) Commission management maintained effective internal control over financial reporting and compliance with laws and regulations. Also, we tested Commission management's compliance with selected laws and regulations. The American Battle Monuments Commission was created in 1923 to commemorate the sacrifices and achievements of U.S. Armed Forces where they have served overseas since April 6, 1917, and locations within the United States as directed by Congress. The Commission designs, administers, operates, and maintains 24 American military cemeteries on foreign soil and 25 federal memorials, monuments, and markers, 22 of which are on foreign soil. The Commission was also responsible for designing and constructing the national World War II Memorial on the Capitol Mall in Washington, D.C., and for maintaining 4 nonfederal memorials with funds provided …
Date: March 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
High-Risk Series: An Update (open access)

High-Risk Series: An Update

A letter report issued by the Government Accountability Office with an abstract that begins "GAO's audits and evaluations identify federal programs and operations that, in some cases, are high risk due to their greater vulnerabilities to fraud, waste, abuse, and mismanagement. Increasingly, GAO also is identifying high-risk areas to focus on the need for broad-based transformations to address major economy, efficiency, or effectiveness challenges. Since 1990, GAO has periodically reported on government operations that it has designated as high risk. In this 2005 update for the 109th Congress, GAO presents the status of high-risk areas identified in 2003 and new high-risk areas warranting attention by the Congress and the administration. Lasting solutions to high-risk problems offer the potential to save billions of dollars, dramatically improve service to the American public, strengthen public confidence and trust in the performance and accountability of our national government, and ensure the ability of government to deliver on its promises."
Date: January 1, 2005
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
System of systems modeling and analysis. (open access)

System of systems modeling and analysis.

This report documents the results of an LDRD program entitled 'System of Systems Modeling and Analysis' that was conducted during FY 2003 and FY 2004. Systems that themselves consist of multiple systems (referred to here as System of Systems or SoS) introduce a level of complexity to systems performance analysis and optimization that is not readily addressable by existing capabilities. The objective of the 'System of Systems Modeling and Analysis' project was to develop an integrated modeling and simulation environment that addresses the complex SoS modeling and analysis needs. The approach to meeting this objective involved two key efforts. First, a static analysis approach, called state modeling, has been developed that is useful for analyzing the average performance of systems over defined use conditions. The state modeling capability supports analysis and optimization of multiple systems and multiple performance measures or measures of effectiveness. The second effort involves time simulation which represents every system in the simulation using an encapsulated state model (State Model Object or SMO). The time simulation can analyze any number of systems including cross-platform dependencies and a detailed treatment of the logistics required to support the systems in a defined mission.
Date: January 1, 2005
Creator: Campbell, James E.; Anderson, Dennis James; Longsine, Dennis E. & Shirah, Donald N.
System: The UNT Digital Library
Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors. (open access)

Chemical crosslinking and mass spectrometry studies of the structure and dynamics of membrane proteins and receptors.

Membrane proteins make up a diverse and important subset of proteins for which structural information is limited. In this study, chemical cross-linking and mass spectrometry were used to explore the structure of the G-protein-coupled photoreceptor bovine rhodopsin in the dark-state conformation. All experiments were performed in rod outer segment membranes using amino acid 'handles' in the native protein sequence and thus minimizing perturbations to the native protein structure. Cysteine and lysine residues were covalently cross-linked using commercially available reagents with a range of linker arm lengths. Following chemical digestion of cross-linked protein, cross-linked peptides were identified by accurate mass measurement using liquid chromatography-fourier transform mass spectrometry and an automated data analysis pipeline. Assignments were confirmed and, if necessary, resolved, by tandem MS. The relative reactivity of lysine residues participating in cross-links was evaluated by labeling with NHS-esters. A distinct pattern of cross-link formation within the C-terminal domain, and between loop I and the C-terminal domain, emerged. Theoretical distances based on cross-linking were compared to inter-atomic distances determined from the energy-minimized X-ray crystal structure and Monte Carlo conformational search procedures. In general, the observed cross-links can be explained by re-positioning participating side-chains without significantly altering backbone structure. One exception, between C3 …
Date: March 1, 2005
Creator: Haskins, William E.; Leavell, Michael D.; Lane, Pamela; Jacobsen, Richard B.; Hong, Joohee; Ayson, Marites J. et al.
System: The UNT Digital Library
Control of a high beta maneuvering reentry vehicle using dynamic inversion. (open access)

Control of a high beta maneuvering reentry vehicle using dynamic inversion.

The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to perform the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for …
Date: May 1, 2005
Creator: Watts, Alfred Chapman
System: The UNT Digital Library
Calendar Year 2004 Groundwater Monitoring Report, U.S. Department of Energy Y-12 National Security Complex, Oak Ridge, Tennessee (open access)

Calendar Year 2004 Groundwater Monitoring Report, U.S. Department of Energy Y-12 National Security Complex, Oak Ridge, Tennessee

This report contains the groundwater and surface water monitoring data that were obtained during calendar year (CY) 2004 at the U.S. Department of Energy (DOE) Y-12 National Security Complex (hereafter referenced as Y-12) on the DOE Oak Ridge Reservation (ORR) in Oak Ridge, Tennessee. The CY 2004 monitoring data were obtained from groundwater and surface water sampling locations in three hydrogeologic regimes at Y-12 (Figure A.1). The Bear Creek Hydrogeologic Regime (Bear Creek Regime) encompasses a section of Bear Creek Valley (BCV) between the west end of Y-12 and the west end of the Bear Creek Watershed (directions are in reference to the Y-12 grid system). The Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime) encompasses the Y-12 industrial facilities and support structures in BCV. The Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime) encompasses a section of Chestnut Ridge south of Y-12. The CY 2004 monitoring data were obtained under the Y-12 Groundwater Protection Program (GWPP) managed by BWXT Y-12, L.L.C. (BWXT) and several monitoring programs managed by Bechtel Jacobs Company LLC (BJC). Data contained in this report meet applicable requirements of DOE Order 450.1 (Environmental Protection Program) regarding evaluation of groundwater and surface water quality in areas: …
Date: September 1, 2005
Creator: unknown
System: The UNT Digital Library
Dipole radiation from a cylindrical hole in the earth. (open access)

Dipole radiation from a cylindrical hole in the earth.

This report examines the problem of an antenna radiating from a cylindrical hole in the earth and the subsequent far-zone field produced in the upper air half space. The approach used for this analysis was to first examine propagation characteristics along the hole for surrounding geologic material properties. Three cases of sand with various levels of moisture content were considered as the surrounding material to the hole. For the hole diameters and sand cases examined, the radiation through the earth medium was found to be the dominant contribution to the radiation transmitted through to the upper half-space. In the analysis presented, the radiation from a vertical and a horizontal dipole source within the hole is used to determine a closed-form expression for the radiation in the earth medium which represents a modified element factor for the source and hole combination. As the final step, the well-known results for a dipole below a half space, in conjunction with the use of Snell's law to transform the modified element factor to the upper half space, determine closed-form expressions for the far-zone radiated fields in the air region above the earth.
Date: August 1, 2005
Creator: Warne, Larry Kevin; Johnson, William Arthur & Basilio, Lorena I.
System: The UNT Digital Library
PACFEST 2004 : enabling technologies for maritime security in the Pacific region. (open access)

PACFEST 2004 : enabling technologies for maritime security in the Pacific region.

In October of 2003 experts involved in various aspects of homeland security from the Pacific region met to engage in a free-wheeling discussion and brainstorming (a 'fest') on the role that technology could play in winning the war on terrorism in the Pacific region. The result was a concise and relatively thorough definition of the terrorism problem in the Pacific region, emphasizing the issues unique to Island nations in the Pacific setting, along with an action plan for developing working demonstrations of advanced technological solutions to these issues. Since PacFest 2003, the maritime dimensions of the international security environment have garnered increased attention and interest. To this end, PacFest 2004 sought to identify gaps and enabling technologies for maritime domain awareness and responsive decision-making in the Asia-Pacific region. The PacFest 2004 participants concluded that the technologies and basic information building blocks exist to create a system that would enable the Pacific region government and private organizations to effectively collaborate and share their capabilities and information concerning maritime security. The proposed solution summarized in this report integrates national environments in real time, thereby enabling effective prevention and first response to natural and terrorist induced disasters through better use of national and …
Date: June 1, 2005
Creator: Moore, Judy Hennessey; Whitley, John B. & Chellis, Craig (Pacific Disaster Center, Kihei, HI)
System: The UNT Digital Library
Habitat Evaluation Procedures (HEP) Report : Oxbow Conservation Area, 2002-2005 Technical Report. (open access)

Habitat Evaluation Procedures (HEP) Report : Oxbow Conservation Area, 2002-2005 Technical Report.

This Habitat Evaluation Procedure (HEP) study was performed to determine baseline habitat units on the Oxbow Conservation Area in Grant County, Oregon. The evaluation is a required part of the Memorandum of Agreement between the Confederated Tribes of the Warm Springs and Bonneville Power Administration (BPA) relating to the acquisition and management of the Oxbow Conservation Area. The HEP team was comprised of individuals from the Washington Department of Fish and Wildlife and the Confederated Tribes of the Warm Springs Reservation of Oregon. The survey was conducted using the following HEP evaluation models for key species: black-capped chickadee (Poecile atricapilla), mallard (Anas platyrhynchos), mink (Mustela vison), western meadowlark (Sturnella neglecta), white-tailed deer (Odocoileus virginiana), and yellow warbler (Dendroica petechia). Cover types used in this survey were conifer forest, irrigated meadow, riparian meadow, upland meadow, riparian shrub, upland shrub, and mine tailings. The project generated 701.3 habitat units for mitigation crediting purposes. Results for each HEP species are: (1) Black-capped chickadee habitat was good, with only isolated areas lacking snags or having low tree canopy cover. (2) Mallard habitat was poor in upland meadows and marginal elsewhere due to a lack of herbaceous/shrub cover and low herbaceous height. (3) Mink habitat …
Date: February 1, 2005
Creator: Cochran, Brian
System: The UNT Digital Library
External Second Gate-Fourier Transform Ion Mobility Spectrometry. (open access)

External Second Gate-Fourier Transform Ion Mobility Spectrometry.

Ion mobility spectrometry (IMS) is recognized as one of the most sensitive and versatile techniques for the detection of trace levels of organic vapors. IMS is widely used for detecting contraband narcotics, explosives, toxic industrial compounds and chemical warfare agents. Increasing threat of terrorist attacks, the proliferation of narcotics, Chemical Weapons Convention treaty verification as well as humanitarian de-mining efforts has mandated that equal importance be placed on the analysis time as well as the quality of the analytical data. (1) IMS is unrivaled when both speed of response and sensitivity has to be considered. (2) With conventional (signal averaging) IMS systems the number of available ions contributing to the measured signal to less than 1%. Furthermore, the signal averaging process incorporates scan-to-scan variations decreasing resolution. With external second gate Fourier Transform ion mobility spectrometry (FT-IMS), the entrance gate frequency is variable and can be altered in conjunction with other data acquisition parameters to increase the spectral resolution. The FT-IMS entrance gate operates with a 50% duty cycle and so affords a 7 to 10-fold increase in sensitivity. Recent data on high explosives are presented to demonstrate the parametric optimization in sensitivity and resolution of our system.
Date: January 1, 2005
Creator: Tarver, Edward E., III
System: The UNT Digital Library
2005 Habitat Evaluation Procedure (HEP) Report for the Calispell Creek Project (open access)

2005 Habitat Evaluation Procedure (HEP) Report for the Calispell Creek Project

On July 13, 2004, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the Calispell Creek property, an acquisition completed by the Kalispel Tribe of Indians in February 2004. Evaluation species and appropriate models include Canada goose, mallard, muskrat, yellow warbler, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The Calispell Creek Project provides a total of 138.17 Habitat Units (HUs) for the species evaluated. Emergent wetland habitat provides 5.16 HUs for mallard and muskrat. Grassland provides 132.02 HUs for mallard and Canada goose. Scrub-shrub vegetation provides 0.99 HUs for yellow warbler and white-tailed deer. The objective of using HEP at the Calispell Creek Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at future points in time so that the effect of management activities on wildlife habitat can be quantified. When combined with other tools, the baseline HEP will be used to determine the most effective on-site management, restoration, and enhancement actions to increase habitat suitability for targeted species. The …
Date: February 1, 2005
Creator: Entz, Ray
System: The UNT Digital Library
CFEST Coupled Flow, Energy & Solute Transport Version CFEST005 Theory Guide (open access)

CFEST Coupled Flow, Energy & Solute Transport Version CFEST005 Theory Guide

This document presents the mathematical theory implemented in the CFEST (Coupled Flow, Energy, and Solute Transport) simulator. The simulator is a three-dimensional finite element model that can be used for evaluating flow and solute mass transport. Although the theory for thermal transport is presented in this guide, it has not yet been fully implemented in the simulator. The flow module is capable of simulating both confined and unconfined aquifer systems, as well as constant and variable density fluid flows. For unconfined aquifers, the model uses a moving boundary for the water table, deforming the numerical mesh so that the uppermost nodes are always at the water table. For solute transport, changes in concentration of a single dissolved chemical constituent are computed for advective and hydrodynamic transport, linear sorption represented by a retardation factor, and radioactive decay. Once fully implemented, transport of thermal energy in the groundwater and solid matrix of the aquifer can also be used to model aquifer thermal regimes. Mesh construction employs “collapsible”, hexahedral finite elements in a three-dimensional coordinate system. CFEST uses the Galerkin finite element method to convert the partial differential equations to algebraic form. To solve the coupled equations for momentum, solute and heat transport, …
Date: November 1, 2005
Creator: Freedman, Vicky L.; Chen, Yousu & Gupta, Sumant K.
System: The UNT Digital Library
Multi-unit operations considerations. (open access)

Multi-unit operations considerations.

Several nuclear weapons programs have or are pursuing the implementation of multi-unit operations for tasks such as disassembly and inspection, and rebuild. A multi-unit operation is interpreted to mean the execution of nuclear explosive operating procedures in a single facility by two separate teams of technicians. The institution of a multi-unit operations program requires careful consideration of the tools, resources, and environment provided to the technicians carrying out the work. Therefore, a systematic approach is necessary to produce safe, secure, and reliable processes. In order to facilitate development of a more comprehensive multi-unit operations program, the current work details categorized issues that should be addressed prior to the implementation of multi-unit operations in a given weapons program. The issues have been organized into the following categories: local organizational conditions, work process flow/material handling/workplace configuration, ambient environmental conditions, documented safety analysis, and training.
Date: September 1, 2005
Creator: Gilmore, Walter E. (Los Alamos National Laboratory, Los Alamos, NM); Bennett, Thomas C. (Lawrence Livermore National Laboratory, Albuquerque, NM) & Brannon, Nathan Gregory
System: The UNT Digital Library
Technology Gap Analysis for the Detection of Process Signatures Using Less Than Remote Methods (open access)

Technology Gap Analysis for the Detection of Process Signatures Using Less Than Remote Methods

Although remote sensing methods offer advantages for monitoring important illicit process activities, remote and stand-off technologies cannot successfully detect all important processes with the sensitivity and certainty that is desired. The main scope of the program is observables, with a primary focus on chemical signatures. A number of key process signatures elude remote or stand-off detection for a variety of reasons (e.g., heavy particulate emissions that do not propagate far enough for detection at stand-off distances, semi-volatile chemicals that do not tend to vaporize and remain in the environment near the source, etc.). Some of these compounds can provide persistent, process-specific information that is not available through remote techniques; however, the associated measurement technologies have their own set of advantages, disadvantages and technical challenges that may need to be overcome before additional signature data can be effectively and reliably exploited. The main objective of this report is to describe a process to identify high impact technology gaps for important less-than-remote detection applications. The subsequent analysis focuses on the technology development needed to enable exploitation of important process signatures. The evaluation process that was developed involves three interrelated and often conflicting requirements generation activities: • Identification of target signature chemicals with …
Date: January 1, 2005
Creator: Hartman, John S.; Atkinson, David A.; Lind, Michael A.; Maughan, A. D. & Kelly, James F.
System: The UNT Digital Library
Validation of a simple turbulence model suitable for closure of temporally-filtered Navier-Stokes equations using a helium plume. (open access)

Validation of a simple turbulence model suitable for closure of temporally-filtered Navier-Stokes equations using a helium plume.

A validation study has been conducted for a turbulence model used to close the temporally filtered Navier Stokes (TFNS) equations. A turbulence model was purposely built to support fire simulations under the Accelerated Strategic Computing (ASC) program. The model was developed so that fire transients could be simulated and it has been implemented in SIERRA/Fuego. The model is validated using helium plume data acquired for the Weapon System Certification Campaign (C6) program in the Fire Laboratory for Model Accreditation and Experiments (FLAME). The helium plume experiments were chosen as the first validation problem for SIERRA/Fuego because they embody the first pair-wise coupling of scalar and momentum fields found in fire plumes. The validation study includes solution verification through grid and time step refinement studies. A formal statistical comparison is used to assess the model uncertainty. The metric uses the centerline vertical velocity of the plume. The results indicate that the simple model is within the 95% confidence interval of the data for elevations greater than 0.4 meters and is never more than twice the confidence interval from the data. The model clearly captures the dominant puffing mode in the fire but under resolves the vorticity field. Grid dependency of the …
Date: June 1, 2005
Creator: Tieszen, Sheldon Robert; Domino, Stefan Paul & Black, Amalia Rebecca
System: The UNT Digital Library
Characterization of soot properties in two-meter JP-8 pool fires. (open access)

Characterization of soot properties in two-meter JP-8 pool fires.

The thermal hazard posed by large hydrocarbon fires is dominated by the radiative emission from high temperature soot. Since the optical properties of soot, especially in the infrared region of the electromagnetic spectrum, as well as its morphological properties, are not well known, efforts are underway to characterize these properties. Measurements of these soot properties in large fires are important for heat transfer calculations, for interpretation of laser-based diagnostics, and for developing soot property models for fire field models. This research uses extractive measurement diagnostics to characterize soot optical properties, morphology, and composition in 2 m pool fires. For measurement of the extinction coefficient, soot extracted from the flame zone is transported to a transmission cell where measurements are made using both visible and infrared lasers. Soot morphological properties are obtained by analysis via transmission electron microscopy of soot samples obtained thermophoretically within the flame zone, in the overfire region, and in the transmission cell. Soot composition, including carbon-to-hydrogen ratio and polycyclic aromatic hydrocarbon concentration, is obtained by analysis of soot collected on filters. Average dimensionless extinction coefficients of 8.4 {+-} 1.2 at 635 nm and 8.7 {+-} 1.1 at 1310 nm agree well with recent measurements in the overfire …
Date: February 1, 2005
Creator: Suo-Anttila, Jill Marie; Jensen, Kirk A. & Blevins, Linda Gail (Sandia National Laboratories, Livermore, CA)
System: The UNT Digital Library
Synthesis of a photoresponsive polymer and its incorporation into an organic superlattice. (open access)

Synthesis of a photoresponsive polymer and its incorporation into an organic superlattice.

The synthesis of a photoswitchable polymer by grafting an azobenzene dye to methacrylate followed by polymerization is presented. The azobenzene dye undergoes a trans-cis photoisomerization that causes a persistent change in the refractive index of cast polymer films. This novel polymer was incorporated into superlattices prepared by spin casting and the optical activity of the polymer was maintained. A modified coextruder that allows the rapid production of soft matter superlattices was designed and fabricated.
Date: January 1, 2005
Creator: Morales, Alfredo Martin; Rondeau, Chris J. (Sandia National Laboratories, Albuquerque, NM); McElhanon, James Ross & Cole, Phillip James (Sandia National Laboratories, Albuquerque, NM)
System: The UNT Digital Library
Toxin studies using an integrated biophysical and structural biology approach. (open access)

Toxin studies using an integrated biophysical and structural biology approach.

Clostridial neurotoxins, such as botulinum and tetanus, are generally thought to invade neural cells through a process of high affinity binding mediated by gangliosides, internalization via endosome formation, and subsequent membrane penetration of the catalytic domain activated by a pH drop in the endosome. This surface recognition and internalization process is still not well understood with regard to what specific membrane features the toxins target, the intermolecular interactions between bound toxins, and the molecular conformational changes that occur as a result of pH lowering. In an effort to elucidate the mechanism of tetanus toxin binding and permeation through the membrane a simple yet representative model was developed that consisted of the ganglioside G{sub tlb} incorporated in a bilayer of cholesterol and DPPC (dipalmitoylphosphatidyl choline). The bilayers were stable over time yet sensitive towards the binding and activity of whole toxin. A liposome leakage study at constant pH as well as with a pH gradient, to mimic the processes of the endosome, was used to elucidate the effect of pH on the toxin's membrane binding and permeation capability. Topographic imaging of the membrane surface, via in situ tapping mode AFM, provided nanoscale characterization of the toxin's binding location and pore formation …
Date: March 1, 2005
Creator: Last, Julie A.; Schroeder, Anne E.; Slade, Andrea Lynn; Sasaki, Darryl Yoshio; Yip, Christopher M. (University of Toronto, Toronto, Ontario, Canada) & Schoeniger, Joseph S. (Sandia National Laboratories, Livermore, CA)
System: The UNT Digital Library