Prioritizing waste generators is necessary to determine which are the best candidates for Pollution Prevention Opportunity Assessments (PPOAs). This paper describes the Sandia National Laboratories/New Mexico (SNL/NM) PPOA Ranking System. The system uses a multimedia approach that considers hazardous and radioactive waste disposal data, and hazardous chemical usage data (from which air emissions are extrapolated). Pollution prevention information is included, from the SNL Pollution Prevention Opportunities database that identifies waste streams that have readily apparent pollution prevention opportunities. The system also considers the relative costs of waste management and the chargeback fees paid for waste generation. From these data, organizations are ranked with an algorithm developed in Microsoft Access{trademark} on a personal computer. The concept could readily be transferred to other facilities needing to decide where to perform PPOAs.
Cost and schedule overruns are often caused by poor requirements that are produced by people who do not understand the requirements process. This report provides a high-level overview of the system requirements process, explaining types, sources, and characteristics of good requirements. System requirements, however, are seldom stated by the customer. Therefore, this report shows ways to help you work with your customer to discover the system requirements. It also explains terminology commonly used in the requirements development field, such as verification, validation, technical performance measures, and the various design reviews.
Parameter estimation for modern viscoplastic constitutive models often requires data from many tests. Sensitivity coefficients can be used to design an efficient test matrix and reduce testing requirements. The present study derives sensitivity coefficients for each model parameter in the Munson-Dawson constitutive model and evaluates them for several load histories.
Knowledge of the charge efficiency of lead-acid batteries near top-of-charge is important to the design of small photovoltaic systems. In order to know how much energy is required from the photovoltaic array in order to accomplish the task of meeting load, including periodic full battery charge, a detailed knowledge of the battery charging efficiency as a function of state of charge is required, particularly in the high state-of-charge regime, as photovoltaic systems are typically designed to operate in the upper 20 to 30% of battery state-of-charge. This paper presents the results of a process for determining battery charging efficiency near top-of-charge and discusses the impact of these findings on the design of small PV systems.
As the successor to SUNMOS [8], the Puma operating system provides a flexible, lightweight, high performance message passing environment for massively parallel computers. Message passing in Puma is accomplished through the use of a new mechanism known as a portal. Puma is currently running on the Intel Paragon and is being developed for the Intel TeraFLOPS machine. In this paper we discuss issues regarding the development of the Argonne National Laboratory/Mississippi State University implementation of the Message Passing Interface standard on top of portals. Included is a description of the design and implementation for both MPI point-to- point and collective communications, and MPI-2 one-sided communications.
The Nuclear Weapons Guidance Team is an interagency committee led by Earl Whiteman, DOE that chartered the generation of EP40100, Concurrent Qualification and its successor EP401099, Concurrent Engineering and Qualification. As this new philosophy of concurrent operations has evolved and as implementation has been initiated, conflicts and insufficiencies in the remaining Engineering Procedures (EPs) have become more apparent. At the Guidance Team meeting in November 1995, this issue was explored and several approaches were considered. It was concluded at this meeting, that a smaller set of interagency EPs described in a hierarchical system could provide the necessary interagency direction to support complex-wide implementation. This set consolidates many existing EP processes where consistency and commonality are critical to success of the extended enterprise. The Guidance Team subsequently chartered an interagency team to initiate development activity associated with the envisioned new EP set. This team had participation from seven Nuclear Weapons Complex (NWC) sites as well as DOE/AL and DP-14 (team members are acknowledged later in this report). Per the Guidance Team, this team, referred to as the Architecture Subcommittee, was to map out and define an EP Architecture for the interagency EPs, make recommendations regarding a more agile process for EP approval and suggest an aggressive timeline to develop the combined EPs. The Architecture Subcommittee was asked to brief their output at the February Guidance Team meeting. This SAND report documents the results of the Architecture Subcommittee`s recommendations.
Moessbauer spectroscopy has been used to determine the iron-bearing phases in the coal, catalysts, and IOM products used and generated in the Direct Coal Liquefaction (DCL) catalyst testing program at Sandia National Laboratories, New Mexico. DCL experiments were conducted with a Blind Canyon, Utah, coal both thermally and with three different iron-based catalysts: (1) a sulfated hematite catalyst (Fe{sub 2}O{sub 3}/SO{sub 4}{sup 2{minus}}), (2) a 6-line ferrihydrite catalyst, and (3) iron-oxide impregnated directly into coal. The catalysts were added to the coal at both a 0.5 and a 1.0 wt% level and sufficient sulfur was added to ensure complete sulfidation of the iron. The Moessbauer spectrum of the Blind Canyon coal revealed that the major iron-bearing mineral present was ankerite, Ca(Fe,Mg)(CO{sub 3}){sub 2}, which converts firs to {gamma}-Fe (austenitic iron) before undergoing partial sulfidation to pyrrhotite in the thermal runs. The percentages of pyrrhotite formed in the catalytic runs were higher than those in the thermal runs indicating that sulfidation of the added iron occurs more rapidly than with the ankerite. Moessbauer data on the amount of pyrrhotite present does not correlate well with THF and heptane conversion percentages, indicating that other parameters like catalyst dispersion must also be considered.
In this report the authors describe the methods they have developed for producing stable periodic mesoporous silica gels, thin films of mesoporous silica for sensor applications, a route to nonaqueous synthesis, and the use of various additives in controlling the pore size and structure of these materials. Mesoporous silica is formed by templating silica precursors around micelles of cationic quaternary ammonium surfactants. During the synthesis these micelles undergo a phase transition to a hexagonal, lamellar or cubic liquid crystalline state, thus imposing periodic order on the amorphous silica which occupies the interface of the hydrophilic cationic headgroups of the surfactants. The product of the bulk wet synthesis is a gel composed of micron size silica/surfactant particles, each of which consists of one or more crystalline domains of silica condensed around the surfactant template. The wet gel can then be washed and pyrolyzed to remove the surfactant template, yielding the periodic mesoporous silica product.
In an effort to establish joint activities in the disposition of fissile materials from nuclear materials, the US and Russia agreed to conduct joint work to develop consistent comparisons of various alternatives for the disposition of weapons-grade plutonium. Joint working groups were established for the analysis of alternatives for plutonium management for water reactors, fast reactors, storage, geological formations, immobilization and stabilization of solutions and other forms. In addition cross-cutting working groups were established for economic analysis and nonproliferation (NP). This paper reviews the activities of the NP working group in support of these studies. The NP working group provided integrated support in the area of nuclear NP to the other US/Russian Study teams. It involved both domestic safeguards and security and international safeguards. The analysis of NP involved consideration of the resistance to theft or diversion and resistance to retrieval, extraction or reuse.
Polymer-based routes to ceramic oxides take advantage of precursor chemistry and structure to produce materials with a range of pore sizes. Polymer precursor routes to non-oxide ceramics offer products with superior thermal and chemical stability in many cases. Polymethylsilane (PMS), a versatile cross linked SiC precursor, [(MeHSi){sub x}(MeSi){sub y}], was synthesized using published procedures to yield fluid precursors with a low (20--40%) degree of cross linking. Unique, highly cross linked (60--70%), solid polymers were produced under reaction conditions which carefully conserve the volatile monomer. These two polymers were converted to SiC to determine the relative importance of the various contributions to porosity, and to assess the role of precursor structure on porosity development in non-oxides. Initial results indicate that precursor structure has little effect on porosity. The development of the porosity appears to be dominated by high temperature thermochemistry and/or microstructural changes.
Zeolite films are sought as components of molecular sieve membranes. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports, depositing oriented zeolites on supports, and dispersing zeolites in polymeric membranes. In most cases, it is very difficult to control and avoid the formation of cracks and/or pinholes. The approach to membrane synthesis is based on hydrothermally converting films of layered aluminosilicates into zeolite films. The authors have demonstrated this concept by preparing zeolite A membranes on alumina supports from kaolin films. The authors have optimized the process parameters not only for desired bulk properties, but also for preparing thin (ca. 5 {micro}m), continuous zeolite A films. Scanning electron microscopy shows highly intergrown zeolite A crystals over most of the surface area of the membrane, but gas permeation experiments indicate existence of mesoporous defects and/or intercrystalline gaps. It has been demonstrated that the thickness of the final zeolite A membrane can be controlled by limiting the amount of precursor kaolin present in the membrane.
This project focuses on the modification of silica and alumina surfaces by titania and hydrous titanium oxide ion-exchange films, and the use of these modified materials as supports for MoS{sub 2} catalysts. FTIR studies of molybdena interaction with {gamma}-Al{sub 2}O{sub 3} demonstrate that at low loadings Mo interacts with the most basic hydroxyl groups, and that these hydroxyls are associated with tetrahedrally coordinated Al. Furthermore, hydrodesulfurization (HDS) activity as a function of Mo loading shows a maximum in specific activity with loading. The Mo species bound to tetrahedrally coordinated Al sites are therefore believed to be inactive for the HDS reaction. Only after the tetrahedral Al sites have completely consumed does molybdena adsorb on the alumina in a manner that leads to an active catalyst. According to this scheme, the activity of alumina supported MoS{sub 2} catalysts could be greatly improved by either titrating the tetrahedral Al sites with a modifier, or by using {alpha}-Al{sub 2}O{sub 3} which contains no tetrahedrally coordinated Al. HDS tests over MoS{sub 2} supported on both {alpha}-Al{sub 2}O{sub 3} and {gamma}-Al{sub 2}O{sub 3} modified by a titania film confirm this hypothesis. Neither support material gives rise to a maximum in activity with Mo loading, but rather exhibits a smooth decrease in activity with loading. Furthermore, for equivalent Mo loadings the activity of both of these support materials exceeds that of unmodified {gamma}-Al{sub 2}O{sub 3} due to the fact that no Mo is tied up in the inactive form. FTIR, XPS, and TEM are currently being used to determine whether the model can indeed account for the observed activity trends. Although the surface area of {alpha}-Al{sub 2}O{sub 3} is too low for use as a commercial catalyst, the titania coated {gamma}-Al{sub 2}O{sub 3} represents an important, practical improvement in support materials for hydrotreating catalysts.
The DOE/DOD Environmental Data Bank was established in 1959 as a central location for storing weapons and equipment environments information from a variety of DOE, DOD, and industrial sources and continues to be maintained by Sandia National Laboratories. The Environmental Data Bank contains approximately 2,900 documents regarding normal and abnormal environments that describe the handling, storage, transportation, use, and general phases, which occur during the life of a weapon system. The Environmental Data Bank contains a vast assortment of resources that document crash, fire, and chemical environments resulting from aircraft, rail, ship, and truck accidents, as well as crash and thermal tests conducted on shipping containers. Also included are studies on the hazards of exposure to liquid natural gas fireballs, chemical fireballs, and hydrogen fireballs. This paper describes the DOE/DOD Environmental Data Bank system, its structure, data sources, and usage, with particular emphasis on its use for safety assessments at Sandia National Laboratories.
In this paper the authors identify factors which influence the safety philosophy used in the US commercial/industrial sector and compare them against those factors which influence nuclear weapons safety. Commercial/industrial safety is guided by private and public safety standards. Generally, private safety standards tend to emphasize product reliability issues while public (i.e., government) safety standards tend to emphasize human factors issues. Safety in the nuclear weapons arena is driven by federal requirements and memoranda of understanding (MOUs) between the Departments of Defense and Energy. Safety is achieved through passive design features integrated into the nuclear weapon. Though the common strand between commercial/industrial and nuclear weapons safety is the minimization of risk posed to the general population (i.e., public safety), the authors found that each sector tends to employ a different safety approach to view and resolve high-consequence safety issues.
Over forty safety and security related research and development projects have been initiated between Sandia National Laboratories and the Russian nuclear weapons laboratories VNIIEF and VNIITF. About half of these projects have been completed. All relate to either safety or security methodology development, processes, accident environment analysis and testing, accident databases, assessments or product design of devices. All projects have a potential benefit to various safety or security programs and some may directly have commercial applications. In general, these projects could benefit risk assessments associated with systems that could result in accidents or incidents having high public consequences. These systems typically have already been engineered to have very low assessed probabilities of occurrence of such accidents or incidents. This paper gives an overview of the Sandia surety program with a focus on the potential for future collaboration between Sandia, three Russian Institutes; VNIIEF, VNIITF and VNIIA, and other industry and government organizations. The intent is to serve as an introduction to a roundtable session on Russian Safety Collaboration at the 14th International System Safety Conference. The current Sandia collaboration program scope and rationale is presented along with the evolved program focus. An overview of the projects is given and a few specific projects are briefly highlighted with tangible results to date.
Much work has been devoted to high consequence events with low frequency of occurrence. Characteristic of these events are bridge failure (such as that of the Tacoma Narrows), building failure (such as the collapse of a walkway at a Kansas City hotel), or compromise of a major chemical containment system (such as at Bhopal, India). Such events, although rare, have an extreme personal, societal, and financial impact. An interesting variation is demonstrated by financial losses due to fraud and abuse in the money management system. The impact can be huge, entailing very high aggregate costs, but these are a result of the contribution of many small attacks and not the result of a single (or few) massive events. Public awareness is raised through publicized events such as the junk bond fraud perpetrated by Milikin or gross mismanagement in the failure of the Barings Bank through unsupervised trading activities by Leeson in Singapore. These event,s although seemingly large (financial losses may be on the order of several billion dollars), are but small contributors to the estimated $114 billion loss to all types of financial fraud in 1993. This paper explores the magnitude of financial system losses and identifies new areas for analysis of high consequence events including the potential effect of malevolent intent.
One of the benefits resulting from the collapse of the Soviet Union is the increased dialogue currently taking place between American and Russian nuclear weapons scientists in various technical arenas. One of these arenas currently being investigated involves collaborative studies which illustrate how risk assessment is perceived and utilized in the Former Soviet Union (FSU). The collaborative studies indicate that, while similarities exist with respect to some methodologies, the assumptions and approaches in performing risk assessments were, and still are, somewhat different in the FSU as opposed to that in the US. The purpose of this paper is to highlight the present knowledge of risk assessment methodologies and philosophies within the two largest nuclear weapons laboratories of the Former Soviet Union, Arzamas-16 and Chelyabinsk-70. Furthermore, This paper will address the relative progress of new risk assessment methodologies, such as Fuzzy Logic, within the framework of current risk assessment methods at these two institutes.
Over the past several years, the authors have performed experimental studies focused on understanding small-scale flow processes within discrete fractures and individual matrix blocks; much of the understanding gained in that time differs from that underlying the basic assumptions used in effective media representations. Here they synthesize the process level understanding gained from their laboratory studies to explore how such small-scale processes may influence the behavior of fluid flow in fracture networks and ensembles of matrix blocks at levels sufficient to impact the formulation of intermediate-scale effective media properties. They also explore, by means of a thought experiment, how these same small-scale processes could couple to produce a large-scale system response inconsistent with current conceptual models based on continuum representations of flow through unsaturated, fractured rock. Based on their findings, a number of modifications to existing dual permeability models are suggested that should allow them improved applicability; however, even with these modifications, it is likely that continuum representations of flow through unsaturated fractured rock will have limited validity and must therefore be applied with caution.
The goal of this work is to extend the use of existing path expression theory and methodologies to ensure that critical software event sequences are maintained even in the face of malevolent attacks and harsh or unstable operating environments. This will be accomplished by providing dynamic fault management measures directly to the software developer and to their varied development environments. This paper discusses the perceived problems, a brief overview of path expressions, and the author`s proposed extension areas. The authors discuss how the traditional path expression usage and implementation differs from the intended usage and implementation.
Garnet phosphors have potential for use in field emission displays (FEDs). Green-emitting Gd{sub 3}Ga{sub 5}O{sub 12}:Tb (GGG:Tb) and Y{sub 3}Al{sub 5}O{sub 12}:Tb (YAG:Tb) are possible alternatives to ZnO:Zn, because of their excellent resistance to burn, low-voltage efficiency, (3.5 lm/W from GGG:Tb at 800 V), and saturation resistance at high power densities. Hydrothermal and combustion synthesis techniques were employed to improve the low-voltage efficiency of YAG:Tb, and Y{sub 3}Ga{sub 5}O{sub 12}:Tb (YGG:Tb). Synthetic technique did not affect low-voltage (100--1,000 V) efficiency, but affected the particle size, morphology, and burn resistance. The small particle size phosphors obtained via hydrothermal (<1 {micro}m) and combustion reactions (<1 {micro}m) would benefit projection TV, high-definition TV (HDTV), and heads-up displays (HUDs), where smaller pixel sizes are required for high resolution.
Inductively Coupled Plasma (ICP) sources are extremely promising for large-area, high-ion density etching or deposition processes. In this review the authors compare results for GaAs and GaN etching with both ICP and Electron Cyclotron Resonance (ECR) sources on the same single-wafer platform. The ICP is shown to be capable of very high rates with excellent anisotropy for fabrication of GaAs vias or deep mesas in GaAs or GaN waveguide structures.
Vulnerability analyses for information systems are complicated because the systems are often geographically distributed. Sandia National Laboratories has assembled an interdisciplinary team to explore the applicability of probabilistic logic modeling (PLM) techniques (including vulnerability and vital area analysis) to examine the risks associated with networked information systems. The authors have found that the reliability and failure modes of many network technologies can be effectively assessed using fault trees and other PLM methods. The results of these models are compatible with an expanded set of vital area analysis techniques that can model both physical locations and virtual (logical) locations to identify both categories of vital areas simultaneously. These results can also be used with optimization techniques to direct the analyst toward the most cost-effective security solution.
The in-scattering processes, which reduce the decay of the active medium polarization, should be included in a consistent treatment of semiconductor laser gain. The in-scattering processes affect the laser gain by decreasing the influence of the high k-states, which contribute absorption to the spectrum. A theory, based on the semiconductor-Bloch equations with the effects of carrier-carrier scattering treated at the level of the quantum kinetic equations in the Markov limit, predicts gain spectra that do not exhibit absorption below the renormalized band gap, in agreement with experiment. When compared to gain calculations where the in-scattering contribution is neglected, the theory predicts markedly different properties for intrinsic laser parameters, such as peak gain, gain bandwidth, differential gain and carrier density at transparency, especially at low carrier densities.
Critical software must be safe, secure, and dependable. Traditionally, these have been pursued as separate disciplines. This presentation looks at the traditional approaches and highlights commonalities and differences among them. Each can learn from the history of the others. More importantly, it is imperative to seek a systems approach which blends all three.
Test data on canonical weapon-like fixtures are used to validate previously developed analytical bounding results. The test fixtures were constructed to simulate (but be slightly worse than) weapon ports of entry but have known geometries (and electrical points of contact). The exterior of the test fixtures exhibited exterior resonant enhancement of the incident fields at the ports of entry with magnitudes equal to those of weapon geometries. The interior consisted of loaded transmission lines adjusted to maximize received energy or voltage but incorporating practical weapon geometrical constraints. New analytical results are also presented for bounding the energies associated with multiple bolt joints and for bounding the exterior resonant enhancement of the exciting fields.
