400 Matching Results

Search Results

Advanced search parameters have been applied.

Small Sample Properties of an Adaptive Filter with Application to Low Volume Statistical Process Control

Description: In many manufacturing environments such as the nuclear weapons complex, emphasis has shifted from the regular production and delivery of large orders to infrequent small orders. However, the challenge to maintain the same high quality and reliability standards while building much smaller lot sizes remains. To meet this challenge, specific areas need more attention, including fast and on-target process start-up, low volume statistical process control, process characterization with small experiments, and estimating reliability given few actual performance tests of the product. In this paper we address the issue of low volume statistical process control. We investigate an adaptive filtering approach to process monitoring with a relatively short time series of autocorrelated data. The emphasis is on estimation and minimization of mean squared error rather than the traditional hypothesis testing and run length analyses associated with process control charting. We develop an adaptive filtering technique that assumes initial process parameters are unknown, and updates the parameters as more data become available. Using simulation techniques, we study the data requirements (the length of a time series of autocorrelated data) necessary to adequately estimate process parameters. We show that far fewer data values are needed than is typically recommended for process control applications. We also demonstrate the techniques with a case study from the nuclear weapons manufacturing complex.
Date: September 1, 1999
Creator: CROWDER, STEPHEN V.
Partner: UNT Libraries Government Documents Department

Chemometric Analysis of Two Dimensional Decay Data: Application to {sup 17}O NMR Relaxation Matrices

Description: The use of {sup 17}O NMR spectroscopy as a tool to investigate aging in polymer systems has recently been demonstrated. Because the natural abundance of {sup 17}O is extremely low (0.037%), the use of labeled {sup 17}O{sub 2} during the oxidation of polymers produces {sup 17}O NMR spectra whose signals arise entirely from the degradation species (i.e. signals from the bulk or unaged material are not observed). This selective isotopic labeling eliminates the impact of interference from the unaged material, cause (1) above. As discussed by Alam et al. spectral overlap between different degradation species as well as errors in quantification remains a major difficulty in {sup 17}O NMR spectroscopy. As a demonstration of the DECRA and CTBSA methods, relaxation matrices obtained from {sup 17}O NMR for model alcohol systems are evaluated. The benefits and limitations of these newly developed chemometric techniques are discussed.
Date: March 18, 1999
Creator: Alam, M.K. & Alam, T.M.
Partner: UNT Libraries Government Documents Department

Historical Exposures to Chemicals at the Rocky Flats Nuclear Weapons Plant: A Pilot Retrospective Exposure Assessment

Description: In a mortality study of white males who had worked at the Rocky Flats Nuclear Weapons Plant between 1952 and 1979, an increased number of deaths from benign and unspecified intracranial neoplasms was found. A case-control study nested within this cohort investigated the hypothesis that an association existed between brain tumor death and exposure to either internally deposited plutonium or external ionizing radiation. There was no statistically significant association found between estimated radiation exposure from internally deposited plutonium and the development of brain tumors. Exposure by job or work area showed no significant difference between the cohort and the control groups. An update of the study found elevated risk estimates for (1) all lymphopoietic neoplasms, and (2) all causes of death in employees with body burdens greater than or equal to two nanocuries of plutonium. There was an excess of brain tumors for the entire cohort. Similar cohort studies conducted on worker populations from other plutonium handling facilities have not yet shown any elevated risks for brain tumors. Historically, the Rocky Flats Nuclear Weapons Plant used large quantities of chemicals in their production operations. The use of solvents, particularly carbon tetrachloride, was unique to Rocky Flats. No investigation of the possible confounding effects of chemical exposures was done in the initial studies. The objectives of the present study are to (1) investigate the history of chemical use at the Rocky Flats facility; (2) locate and analyze chemical monitoring information in order to assess employee exposure to the chemicals that were used in the highest volume; and (3) determine the feasibility of establishing a chemical exposure assessment model that could be used in future epidemiology studies.
Date: February 1, 1999
Creator: Robertson, Janeen Denise
Partner: UNT Libraries Government Documents Department

Range gated imaging experiments using gated intensifiers

Description: A variety of range gated imaging experiments using high-speed gated/shuttered proximity focused microchannel plate image intensifiers (MCPII) are reported. Range gated imaging experiments were conducted in water for detection of submerged mines in controlled turbidity tank test and in sea water for the Naval Coastal Sea Command/US Marine Corps. Field experiments have been conducted consisting of kilometer range imaging of resolution targets and military vehicles in atmosphere at Eglin Air Force Base for the US Air Force, and similar imaging experiments, but in smoke environment, at Redstone Arsenal for the US Army Aviation and Missile Command (AMCOM). Wavelength of the illuminating laser was 532 nm with pulse width ranging from 6 to 12 ns and comparable gate widths. These tests have shown depth resolution in the tens of centimeters range from time phasing reflected LADAR images with MCPII shutter opening.
Date: March 1, 1999
Creator: McDonald, T.E. Jr.; Yates, G.J.; Cverna, F.H.; Gallegos, R.A.; Jaramillo, S.A.; Numkena, D.M. et al.
Partner: UNT Libraries Government Documents Department

Quantum cryptography for secure free-space communications

Description: The secure distribution of the secret random bit sequences known as key material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is a new technique for secure key distribution with single-photon transmissions: Heisenberg`s uncertainty principle ensures that an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). The authors have developed experimental quantum cryptography systems based on the transmission of non-orthogonal photon polarization states to generate shared key material over line-of-sight optical links. Key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. The authors have developed and tested a free-space quantum key distribution (QKD) system over an outdoor optical path of {approximately}1 km at Los Alamos National Laboratory under nighttime conditions. Results show that free-space QKD can provide secure real-time key distribution between parties who have a need to communicate secretly. Finally, they examine the feasibility of surface to satellite QKD.
Date: March 1, 1999
Creator: Hughes, R. J.; Buttler, W. T.; Kwiat, P. G.; Lamoreaux, S. K.; Luther, G. G.; Morgan, G. L. et al.
Partner: UNT Libraries Government Documents Department

ASCI application performance and the impact of commodity processor architectural trends

Description: The DOE Accelerated Strategic Computing Initiative (ASCI) is an applications-driven program requiring use of scalable, high-performance architectures to meet aggressive engineering needs related to safety of the Nation`s nuclear stockpile. ASCI will accelerate development of computational methods and tools for predictive simulation and for virtual prototyping needed to re-certify the existing stockpile, assess the effects of component aging, and to evaluate accident scenarios. The purpose of this paper is to summarize recent performance results from an important ASCI-related application and to speculate on how trends within the computer industry and in computer architecture relate to these results.
Date: June 1999
Creator: Lubeck, O.; Hoisie, A.; Bassetti, F.; Cameron, K.; Luo, Y. & Wasserman, H.
Partner: UNT Libraries Government Documents Department

An explicit model of expanding cylindrical shells subjected to high explosive detonations

Description: A viscoplastic constitutive model was formulated to model the high strain-rate expansion of thin cylindrical shells subjected to internal explosive detonations. This model provides insight into the development of plastic instabilities, which occur on the surface of the shells prior to failure. The effects of shock heating and damage in the form of microvoid nucleation, growth, and coalescence were incorporated using the Johnson-Cook strength model with the Mie-Grueneisen equation of state and a modified Gurson yield surface. This model was implemented into ABAQUS/Explicit as a user material subroutine. A cylindrical copper shell was modeled using both axisymmetric and plane strain elements. The high explosive material inside of the cylinder was simulated using the high explosive burn model in ABAQUS/Explicit. Two experiments were conducted involving explosive-filled, copper cylinders and good agreement was obtained between the numerical results and experimental data.
Date: April 1, 1999
Creator: Martineau, R.L.; Prime, M.B.; Anderson, C.A. & Smith, F.W.
Partner: UNT Libraries Government Documents Department

Thermal Decomposition Characteristics of Orthorhombic Ammonium Perchlorate (o-AP)

Description: Preliminary STMBMS and SEM results of the thermal decomposition of AP in the orthorhombic phase are presented. The overall decomposition is shown to be complex and controlled by both physical and chemical processes. The data show that the physical and chemical processes can be probed and characterized utilizing SEM and STMBMS. The overall decomposition is characterized by three distinguishing features: an induction period, and accelerator period and a deceleratory period. The major decomposition event occurs in the subsurface of the AP particles and propagates towards the center of the particle with time. The amount of total decomposition is dependent upon particle size and increases from 23% for {approximately}50{micro}m-diameter AP to 33% for {approximately}200{micro}m-diameter AP. A conceptual model of the physical processes is presented. Insight into the chemical processes is provided by the gas formation rates that are measured for the gaseous products. To our knowledge, this is the first presentation of data showing that the chemical and physical decomposition processes can be identified from one another, probed and characterized at the level that is required to better understand the thermal decomposition behavior of AP. Future work is planned with the goal of obtaining data that can be used to develop a mathematical description for the thermal decomposition of o-AP.
Date: March 1, 1999
Creator: Behrens, R. & Minier, L.
Partner: UNT Libraries Government Documents Department

Nevada Test Site, site treatment plan 1999 annual update

Description: A Site Treatment Plan (STP) is required for facilities at which the US Department of Energy Nevada Operations Office (DOE/NV) generates or stores mixed waste (MW), defined by the Federal Facility Compliance Act (FFC Act) as waste containing both a hazardous waste subject to the Resource Conservation and Recovery Act (RCRA) and a radioactive material subject to the Atomic Energy Act. This STP was written to identify specific treatment facilities for treating DOE/NV generated MW and provides proposed implementation schedules. This STP was approved by the Nevada Division of Environmental Protection (NDEP) and provided the basis for the negotiation and issuance of the FFC Act Consent Order (CO) dated March 6, 1996, and revised June 15, 1998. The FFC Act CO sets forth stringent regulatory requirements to comply with the implementation of the STP.
Date: March 1, 1999
Partner: UNT Libraries Government Documents Department

Flow distribution in the accelerator-production-of-tritium target

Description: Achieving nearly uniform flow distributions in the accelerator production of tritium (APT) target structures is an important design objective. Manifold effects tend to cause a nonuniform distribution in flow systems of this type, although nearly even distribution can be achieved. A program of hydraulic experiments is underway to provide a database for validation of calculational methodologies that may be used for analyzing this problem and to evaluate the approach with the most promise for achieving a nearly even flow distribution. Data from the initial three tests are compared to predictions made using four calculational methods. The data show that optimizing the ratio of the supply-to-return-manifold areas can produce an almost even flow distribution in the APT ladder assemblies. The calculations compare well with the data for ratios of the supply-to-return-manifold areas spanning the optimum value. Thus, the results to date show that a nearly uniform flow distribution can be achieved by carefully sizing the supply and return manifolds and that the calculational methods available are adequate for predicting the distributions through a range of conditions.
Date: January 1, 1999
Creator: Siebe, D.A.; Spatz, T.L.; Pasamehmetoglu, K.O. & Sherman, M.P.
Partner: UNT Libraries Government Documents Department

Evaluation of the hydrologic source term from underground nuclear tests in Frenchman Flat at the Nevada Test Site: The Cambric test

Description: The objectives of this project are to develop and apply a modeling frame- work to quantitatively evaluate the nature and extent of radionuclide migration within the immediate, near field environment about an underground nuclear test. Specifically, it will involve evaluation of ² The speciation and abundance of radionuclides that are introduced into groundwater as aqueous species or colloids, and ² The rate and extent of radionuclide movement, dilution, and reaction in groundwater surrounding the working point of a test. To be clear, interest will only be focused on processes that have occurred well after the nuclear test, as opposed to the more dynamic processes that take place during or immediately after detonation. The meaning of "near field" in this case will loosely refer to a volume of diameter 4-8 R<sub>c</sub>, centered on the working point and chimney of the test, where Rc is the radius of the blast cavity. For a given nuclear test, this information will collectively comprise the test's "hydrologic source term". This work relies on and is being supported by existing data, analyses, and interpretations that have been made at the Nevada Test Site (NTS) during the American nuclear test program and previous and ongoing studies related to radionuclide migration in the subsurface (Kersting, 1996).
Date: March 23, 1999
Creator: Bourcier, W L; Bruton, C J; Carle, S F; Kersting, A B; Pawloski, G A; Rard, J A et al.
Partner: UNT Libraries Government Documents Department

The History of Metals and Ceramics Division

Description: The division was formed in 1946 at the suggestion of Dr. Eugene P. Wigner to attack the problem of the distortion of graphite in the early reactors due to exposure to reactor neutrons, and the consequent radiation damage. It was called the Metallurgy Division and assembled the metallurgical and solid state physics activities of the time which were not directly related to nuclear weapons production. William A. Johnson, a Westinghouse employee, was named Division Director in 1946. In 1949 he was replaced by John H Frye Jr. when the Division consisted of 45 people. He was director during most of what is called the Reactor Project Years until 1973 and his retirement. During this period the Division evolved into three organizational areas: basic research, applied research in nuclear reactor materials, and reactor programs directly related to a specific reactor(s) being designed or built. The Division (Metals and Ceramics) consisted of 204 staff members in 1973 when James R. Weir, Jr., became Director. This was the period of the oil embargo, the formation of the Energy Research and Development Administration (ERDA) by combining the Atomic Energy Commission (AEC) with the Office of Coal Research, and subsequent formation of the Department of Energy (DOE). The diversification process continued when James O. Stiegler became Director in 1984, partially as a result of the pressure of legislation encouraging the national laboratories to work with U.S. industries on their problems. During that time the Division staff grew from 265 to 330. Douglas F. Craig became Director in 1992.
Date: January 1, 1999
Creator: Craig, D.F.
Partner: UNT Libraries Government Documents Department

River Protection Project FY 2000 Multi Year Work Plan Summary

Description: The River Protection Project (RPP), formerly the Tank Waste Remediation System (TWRS), is a major part of the U.S. Department of Energy's (DOE) Office of River Protection (ORP). The ORP was established as directed by Congress in Section 3139 of the Strom Thurmond National Defense Authorization Act for Fiscal Year (FY) 1999. The ORP was established to elevate the reporting and accountability for the RPP to the DOE-Headquarters level. This was done to gain Congressional visibility and obtain support for a major $10 billion high-level liquid waste vitrification effort.
Date: August 27, 1999
Creator: LENSEIGNE, D.L.
Partner: UNT Libraries Government Documents Department

Design-Only Conceptual Design Report: Plutonium Immobilization Plant

Description: This design-only conceptual design report was prepared to support a funding request by the Department of Energy Office of Fissile Materials Disposition for engineering and design of the Plutonium Immobilization Plant, which will be used to immobilize up to 50 tonnes of surplus plutonium. The siting for the Plutonium Immobilization Plant will be determined pursuant to the site-specific Surplus Plutonium Disposition Environmental Impact Statement in a Plutonium Deposition Record of Decision in early 1999. This document reflects a new facility using the preferred technology (ceramic immobilization using the can-in-canister approach) and the preferred site (at Savannah River). The Plutonium Immobilization Plant accepts plutonium from pit conversion and from non-pit sources and, through a ceramic immobilization process, converts the plutonium into mineral-like forms that are subsequently encapsulated within a large canister of high-level waste glass. The final immobilized product must make the plutonium as inherently unattractive and inaccessible for use in nuclear weapons as the plutonium in spent fuel from commercial reactors and must be suitable for geologic disposal. Plutonium immobilization at the Savannah River Site uses: (1) A new building, the Plutonium Immobilization Plant, which will convert non-pit surplus plutonium to an oxide form suitable for the immobilization process, immobilize plutonium in a titanate-based ceramic form, place cans of the plutonium-ceramic forms into magazines, and load the magazines into a canister; (2) The existing Defense Waste Processing Facility for the pouring of high-level waste glass into the canisters; and (3) The Actinide Packaging and Storage Facility to receive and store feed materials. The Plutonium Immobilization Plant uses existing Savannah River Site infra-structure for analytical laboratory services, waste handling, fire protection, training, and other support utilities and services. The Plutonium Immobilization Plant may share the disposition of the 50 tonnes of plutonium with the mixed oxide fuel/reactor disposition alternative. For this ...
Date: January 1, 1999
Creator: DiSabatino, A. & Loftus, D.
Partner: UNT Libraries Government Documents Department

Radiocesium Discharges and Subsequent Environmental Transport at the Major U.S. Weapons Production Facilities

Description: Radiocesium is one of the more prevalent radionuclides in the environment as a result of weapons production related atomic projects in the United States and the former Soviet Union. Radiocesium discharges during the 1950's account for a large fraction of the historical releases from U.S. weapons production facilities. Releases of radiocesium to terrestrial and aquatic ecosystems during the early ,years of nuclear weapons production provided the opportunity to conduct multidisciplinary studies on the transport mechanisms of this potentially hazardous radionuclide. The major U.S. Department of Energy facilities (Oak Ridge Reservation in Tennessee, Hanford Site near Richland, Washington, and Savannah River Site near Aiken, South Carolina) are located in regions of the country that have different geographical characteristics. The facility siting provided diverse backgrounds for the development of an understanding of environmental factors contributing to the fate and transport of radiocesium. In this paper, we summarize the significant environmental releases of radiocesium in the early -years of weapons production and then discuss the historically significant transport mechanisms for r37Cs at the three facilities that were part of the U.S. nuclear weapons complex.
Date: November 14, 1999
Creator: Garten, Jr. C.T.; Hamby, D.M. & Schreckhise, R.G.
Partner: UNT Libraries Government Documents Department

Deflection of large near-earth objects

Description: The Earth is periodically hit by near Earth objects (NEOs) ranging in size from dust to mountains. The small ones are a useful source of information, but those larger than about 1 km can cause global damage. The requirements for the deflection of NEOs with significant material strength are known reasonably well; however, the strength of large NEOs is not known, so those requirements may not apply. Meteor impacts on the Earth`s atmosphere give some information on strength as a function of object size and composition. This information is used here to show that large, weak objects could also be deflected efficiently, if addressed properly.
Date: January 11, 1999
Creator: Canavan, G. H.
Partner: UNT Libraries Government Documents Department

Solid Phase Microextraction and Miniature Time-of-Flight Mass Spectrometer

Description: A miniature mass spectrometer, based on the time-of-flight principle, has been developed for the detection of chemical warfare agent precursor molecules. The instrument, with minor modifications, could fulfill many of the needs for sensing organic molecules in various Defense Programs, including Enhanced Surveillance. The basic footprint of the instrument is about that of a lunch box. The instrument has a mass range to about 300, has parts-per-trillion detection limits, and can return spectra in less than a second. The instrument can also detect permanent gases and is especially sensitive to hydrogen. In volume, the device could be manufactured for under $5000.
Date: January 26, 1999
Creator: Hiller, j.m.
Partner: UNT Libraries Government Documents Department

Corrosion in Non-Hermetic Microelectronic Devices

Description: Many types of integrated and discrete microelectronic devices exist in the enduring stockpile. In the past, most of these devices have used conventional ceramic hermetic packaging (CHP) technology. Sometime in the future, plastic encapsulated microelectronic (PEM) devices will almost certainly enter the inventory. In the presence of moisture, several of the aluminum-containing metallization features common to both types of packaging become susceptible to atmospheric corrosion (Figure 1). A breach in hermeticity (e.g., due to a crack in the ceramic body or lid seal) could allow moisture and/or contamination to enter the interior of a CHP device. For PEM components, the epoxy encapsulant material is inherently permeable to moisture. A multi-year project is now underway at Sandia to develop the knowledge base and analytical tools needed to quantitatively predict the effect of corrosion on microelectronic performance and reliability. The issue of corrosion-induced failure surfaced twice during the past year because cracks were found in their ceramic bodies of two different CHP devices: the SA371 1/3712 MOSFET and the SA3935 ASIC (acronym for A Simple Integrated Circuit). Because of our inability to perform a model-based prediction at that time, the decision was made to determine the validity of the corrosion concern for these specific situations by characterizing the expected environment and assessing its relative degree of corrosivity. The results of this study are briefly described in this paper along with some of the advancements made with the predictive model development.
Date: March 16, 1999
Creator: Braithwaite, J. W. & Sorensen, N. R.
Partner: UNT Libraries Government Documents Department

Source and path corrections, feature selection, and outlier detection applied to regional event discrimination in China

Description: The authors are investigating techniques to improve regional discrimination performance in uncalibrated regions. These include combined source and path corrections, spatial path corrections, path-specific waveguide corrections to construct frequency-dependent amplitude corrections that remove attenuation, corner frequency scaling, and source region/path effects (such as blockages). The spatial method and the waveguide method address corrections for specific source regions and along specific paths. After applying the above corrections to phase amplitudes, the authors form amplitude ratios and use a combination of feature selection and outlier detection to choose the best-performing combination of discriminants. Feature selection remains an important issue. Most stations have an inadequate population of nuclear explosions on which to base discriminant selection. Additionally, mining explosions are probably not good surrogates for nuclear explosions. The authors are exploring the feasibility of sampling the source and path corrected amplitudes for each phase as a function of frequency in an outlier detection framework. In this case, the source identification capability will be based on the inability of the earthquake source model to fit data from explosion sources.
Date: March 1, 1999
Creator: Hartse, H.E.; Taylor, S.R.; Phillips, W.S. & Velasco, A.A.
Partner: UNT Libraries Government Documents Department

High explosive violent reaction (HEVR) from slow heating conditions

Description: The high explosives (HEs) developed and used at the Los Alamos National Laboratory are designed to be insensitive to impact and thermal insults under all but the most extreme conditions. Nevertheless, violent reactions do occasionally occur when HE is involved in an accident. The HE response is closely dependent on the type of external stimulus that initiates the reaction. For example, fast heating of conventional HE will probably result in fairly benign burning, while long-term, slow heating of conventional HE is more likely to produce an HEVR that will do much more damage to the immediate surroundings. An HEVR (High Explosive Violent Reaction) can be defined as the rapid release of energy from an explosive that ranges from slightly faster than a deflagration (very rapid burning) to a reaction that approaches a detonation. A number of thermal analyses have been done to determine slow heat/cook-off conditions that produce HE self-heating that can build up to a catastrophic runaway reaction. The author specifies the conditions that control reaction violence, describes experiments that produced an HEVR, describes analyses done to determine a heating rate threshold for HEVR, and lists possible HEVR situations.
Date: March 1, 1999
Creator: Vigil, A.S.
Partner: UNT Libraries Government Documents Department

The use of propagation path corrections to improve regional seismic event location in western China

Description: In an effort to improve the ability to locate seismic events in western China using only regional data, the authors have developed empirical propagation path corrections (PPCs) and applied such corrections using both traditional location routines as well as a nonlinear grid search method. Thus far, the authors have concentrated on corrections to observed P arrival times for shallow events using travel-time observations available from the USGS EDRs, the ISC catalogs, their own travel-tim picks from regional data, and data from other catalogs. They relocate events with the algorithm of Bratt and Bache (1988) from a region encompassing China. For individual stations having sufficient data, they produce a map of the regional travel-time residuals from all well-located teleseismic events. From these maps, interpolated PPC surfaces have been constructed using both surface fitting under tension and modified Bayesian kriging. The latter method offers the advantage of providing well-behaved interpolants, but requires that the authors have adequate error estimates associated with the travel-time residuals. To improve error estimates for kriging and event location, they separate measurement error from modeling error. The modeling error is defined as the travel-time variance of a particular model as a function of distance, while the measurement error is defined as the picking error associated with each phase. They estimate measurement errors for arrivals from the EDRs based on roundoff or truncation, and use signal-to-noise for the travel-time picks from the waveform data set.
Date: March 1, 1999
Creator: Steck, L. K.; Cogbill, A. H. & Velasco, A. A.
Partner: UNT Libraries Government Documents Department

Mechanical Properties for Fracture Analysis of Mild Steel Storage Tasks

Description: Mechanical properties of 1950's vintage, A285 Grade B carbon steels have been compiled for elastic-plastic fracture mechanics analysis of storage tanks (Lam and Sindelar, 1999). The properties are from standard Charpy V-notch (CVN), 0.4T planform Compact Tension (C(T)), and Tensile (T) specimens machined from archival steel from large water piping. The piping and storage tanks were constructed in the 1950s from semi-killed, hot-rolled carbon steel plate specified as A285 Grade B. Evaluation of potential aging mechanisms at both service conditions shows no loss in fracture resistance of the steel in either case.Site and literature data show that the A285, Grade B steel, at and above approximately 70 degrees Fahrenheit, is in the upper transition to upper shelf region for absorbed energy and is not subject to cleavage cracking or a brittle fracture mode. Furthermore, the tank sidewalls are 1/2 or 5/8-inch thick, and therefore, the J-resistance (JR) curve that characterizes material resistance to stable crack extension under elastic-plastic deformation best defines the material fracture toughness. The JR curves for several heats of A285, Grade B steel tested at 40 degrees Fahrenheit, a temperature near the average ductile-to-brittle (DBTT) transition temperature (CVN {at} 15 ft-lb), are presented. This data is applicable to evaluate flaw stability of the storage tanks that are operated above 70 degrees Fahrenheit since, even at 40 degrees Fahrenheit, crack advance is observed to proceed by ductile tearing.
Date: March 3, 1999
Creator: Sindelar, R.L.
Partner: UNT Libraries Government Documents Department

Federal Emergency Management Information System (FEMIS) Bill of Materials (BOM) for FEMIS Version 1.4.6

Description: This document describes the hardware and software required for the Federal Emergency Management Information System version 1.4.6 (FEMIS{copyright} v1.4.6). FEMIS is designed for a single Chemical Stockpile Emergency Preparedness Program (CSEPP) site that has multiple Emergency Operations Centers (EOCs). Each EOC has personal computers (PCs) that emergency planners and operations personnel use to do their jobs. These PCs are connected via a local area network (LAN) to servers that provide EOC-wide services. Each EOC is interconnected to other EOCS via a Wide Area Network (WAN).
Date: March 12, 1999
Creator: Homer, B.J., Johnson, D.M.; Wood, B.M.; Stoops, L.R.; Fangman, P.M.; Johnson, R.L.; Loveall, R.M. et al.
Partner: UNT Libraries Government Documents Department