The Geometric Search Engine is a software system for storing and searching a database of geometric models. The database maybe searched for modeled objects similar in shape to a target model supplied by the user. The database models are generally from CAD models while the target model may be either a CAD model or a model generated from range data collected from a physical object. This document describes key generation, database layout, and search of the database.
This report provides a summary of the work completed in the Source Code Assurance Tool project. This work was done as part of the Laboratory Directed Research and Development program.
This report provides a preliminary functional description of a novel software application, the Source Code Assurance Tool, which would assist a system analyst in the software assessment process. An overview is given of the tool's functionality and design; and how the analyst would use it to assess a body of source code. This work was done as part of a Laboratory Directed Research and Development project.
In this paper we describe a new language, Visual Structure Language (VSL), designed to describe the structure of a program and explain its pieces. This new language is built on top of a general-purpose language, such as C. The language consists of three extensions: explanations, nesting, and arcs. Explanations are comments explicitly associated with code segments. These explanations can be nested. And arcs can be inserted between explanations to show data- or control-flow. The value of VSL is that it enables a developer to better control a code. The developer can represent the structure via nested explanations, using arcs to indicate the flow of data and control. The explanations provide a ''second opinion'' about the code so that at any level, the developer can confirm that the code operates as it is intended to do. We believe that VSL enables a programmer to use in a computer language the same model--a hierarchy of components--that they use in their heads when they conceptualize systems.
We present the tool we built as part of a Laboratory Directed Research and Development (LDRD) project. This tool consists of a commercially-available, graphical editor front-end, combined with a back end ''slicer.'' The significance of the tool is that it shows how to slice across system components. This is an advance from slicing across program components.
This report details experimental data useful in validating radiative transfer codes involving participating media, particularly for cases involving combustion. Special emphasis is on data for pool fires. Features sought in the references are: Flame geometry and fuel that approximate conditions for a pool fire or a well-defined flame geometry and characteristics that can be completely modeled; detailed information that could be used as code input data, including species concentration and temperature profiles and associated absorption coefficients, soot morphology and concentration profiles, associated scattering coefficients and phase functions, specification of system geometry, and system boundary conditions; detailed information that could be compared against code output predictions, including measured boundary radiative energy flux distributions (preferably spectral) and/or boundary temperature distributions; and a careful experimental error analysis so that code predictions could be rationally compared with experimental measurements. Reference data were gathered from more than 35 persons known to be active in the field of radiative transfer and combustion, particularly in experimental work. A literature search was carried out using key words. Additionally, the reference lists in papers/reports were pursued for additional leads. The report presents extended abstracts of the cited references, with comments on available and missing data for code validation, and comments on reported error. A graphic for quick reference is added to each abstract that indicates the completeness of data and how well the data mimics a large-scale pool fire. The references are organized into Lab-Scale Pool Fires, Large-Scale Pool Fires, Momentum-Driven Diffusion Flames, and Enclosure Fires. As an additional aid to report users, the Tables in Appendix A show the types of data included in each reference. The organization of the tables follows that used for the abstracts.
Sandia National Laboratories is developing innovative alternative technology to replace open burn/open detonation (OB/OD) operations for the destruction and disposal of obsolete, excess, and off-spec energetic materials. Alternatives to OB/OD are necessary to comply with increasingly stringent regulations. This program is developing an alternative technology to destruct energetic materials using organic amines with minimal discharge of toxic chemicals to the environment and defining the application of the by-products for the manufacture of structural materials.
Wire explosion experiments have been carried out at the University of Nevada, Reno. These experiments investigated the explosion phase of wires with properties and current-driving conditions comparable to that used in the initial stage of wire array z-pinch implosions on the Z machine at Sandia National Laboratories. Specifically, current pulses similar to and faster than the pre-pulse current on Z (current prior to fast rise in current pulse) were applied to single wire loads to study wire heating and the early development of plasmas in the wire initiation process. Understanding such issues are important to larger pulsed power machines that implode cylindrical wire array loads comprised of many wires. It is thought that the topology of an array prior to its acceleration influences the implosion and final stagnation properties, and therefore may depend on the initiation phase of the wires. Single wires ranging from 4 to 40 pm in diameter and comprised of material ranging from AI to W were investigated. Several diagnostics were employed to determine wire current, voltage, total emitted-light energy and power, along with the wire expansion velocity throughout the explosion. In a number of cases, the explosion process was also observed with x-ray backlighting using x-pinches. The experimental data indicates that the characteristics of a wire explosion depend dramatically on the rate of rise of the current, on the diameter of the wire, and on the heat of vaporization of the wire material. In this report, these characteristics will be described in detail. Of particular interest is the result that a faster current rise produces a higher energy deposition into the wire prior to explosion. This result introduces a different means of increasing the efficiency of wire heating. In this case, the energy deposition along the wire and its subsequent expansion, is uniform compared to a ''slow'' current rise (170 A/ns compared to 22 A /s current rise into a short circuit) and the expansion velocity is larger. The energy deposition and wire expansion is further modified by the wire diameter and material. Investigations of wire diameter indicate that the diameter primarily effects the expansion velocity and energy deposition; thicker wires explode with greater velocities but absorb less energy per atom. The heat of vaporization also categorizes the wire explosion; wires with a low heat of vaporization expand faster and emit less radiation than their high heat of vaporization counterparts.
An important capability in conducting underground nuclear tests is to be able to determine the nuclear test yield accurately within hours after a test. Due to a nuclear test moratorium, the seismic method that has been used in the past has not been exercised since a non-proliferation high explosive test in 1993. Since that time, the seismic recording system and the computing environment have been replaced with modern equipment. This report describes the actions that have been taken to preserve the capability for determining seismic yield, in the event that nuclear testing should resume. Specifically, this report describes actions taken to preserve seismic data, actions taken to modernize software, and actions taken to document procedures. It concludes with a summary of the current state of the data system and makes recommendations for maintaining this system in the future.
This report describes testing of prototype InfiniBand{trademark} host channel adapters from Intel Corporation, using the Linux(reg sign) operating system. Three generations of prototype hardware were obtained, and Linux device drivers were written which exercised the data movement capabilities of the cards. Latency and throughput results obtained were similar to other SAN technologies, but not significantly better.
This project set out to scientifically-tailor ''smart'' interfacial films and 3-D composite nanostructures to exhibit photochromic responses to specific, highly-localized chemical and/or mechanical stimuli, and to integrate them into optical microsystems. The project involved the design of functionalized chromophoric self-assembled materials that possessed intense and environmentally-sensitive optical properties (absorbance, fluorescence) enabling their use as detectors of specific stimuli and transducers when interfaced with optical probes. The conjugated polymer polydiacetylene (PDA) proved to be the most promising material in many respects, although it had some drawbacks concerning reversibility. Throughout his work we used multi-task scanning probes (AFM, NSOM), offering simultaneous optical and interfacial force capabilities, to actuate and characterize the PDA with localized and specific interactions for detailed characterization of physical mechanisms and parameters. In addition to forming high quality mono-, bi-, and tri-layers of PDA via Langmuir-Blodgett deposition, we were successful in using the diacetylene monomer precursor as a surfactant that directed the self-assembly of an ordered, mesostructured inorganic host matrix. Remarkably, the diacetylene was polymerized in the matrix, thus providing a PDA-silica composite. The inorganic matrix serves as a perm-selective barrier to chemical and biological agents and provides structural support for improved material durability in microsystems. Our original goal was to use the composite films as a direct interface with microscale devices as optical elements (e.g., intracavity mirrors, diffraction gratings), taking advantage of the very high sensitivity of device performance to real-time dielectric changes in the films. However, our optical physics colleagues (M. Crawford and S. Kemme) were unsuccessful in these efforts, mainly due to the poor optical quality of the composite films.
The intention of this project was to collaborate with Harvard University in the general area of nanoscale structures, biomolecular materials and their application in support of Sandia's MEMS technology. The expertise at Harvard was crucial in fostering these fundamentally interdisciplinary developments. Areas that were of interest included: (1) nanofabrication that exploits traditional methods (from Si technology) and developing new methods; (2) self-assembly of organic and inorganic systems; (3) assembly and dynamics of membranes and microfluidics; (4) study of the hierarchy of scales in assembly; (5) innovative imaging methods; and (6) hard (engineering)/soft (biological) interfaces. Specifically, we decided to work with Harvard to design and construct an experimental test station to measure molecular transport through single nanopores. The pore may be of natural origin, such as a self-assembled bacterial protein in a lipid bilayer, or an artificial structure in silicon or silicon nitride.
This report documents work supporting the Sandia National Laboratories initiative in Distributed Energy Resources (DERs) and Supervisory Control and Data Acquisition (SCADA) systems. One approach for real-time control of power generation assets using feedback control, Quantitative feedback theory (QFT), has recently been applied to voltage, frequency, and phase-control of power systems at Sandia. QFT provided a simple yet powerful philosophy for designing the control systems--allowing the designer to optimize the system by making design tradeoffs without getting lost in complex mathematics. The feedback systems were effective in reducing sensitivity to large and sudden changes in the power grid system. Voltage, frequency, and phase were accurately controlled, even with large disturbances to the power grid system.
This report is divided into two parts: a study of the glass transition in confined geometries, and formation mechanisms of block copolymer mesophases by solvent evaporation-induced self-assembly. The effect of geometrical confinement on the glass transition of polymers is a very important consideration for applications of polymers in nanotechnology applications. We hypothesize that the shift of the glass transition temperature of polymers in confined geometries can be attributed to the inhomogeneous density profile of the liquid. Accordingly, we assume that the glass temperature in the inhomogeneous state can be approximated by the Tg of a corresponding homogeneous, bulk polymer, but at a density equal to the average density of the inhomogeneous system. Simple models based on this hypothesis give results that are in remarkable agreement with experimental measurements of the glass transition of confined liquids. Evaporation-induced self-assembly (EISA) of block copolymers is a versatile process for producing novel, nanostructured materials and is the focus of much of the experimental work at Sandia in the Brinker group. In the EISA process, as the solvent preferentially evaporates from a cast film, two possible scenarios can occur: microphase separation or micellization of the block copolymers in solution. In the present investigation, we established the conditions that dictate which scenario takes place. Our approach makes use of scaling arguments to determine whether the overlap concentration c* occurs before or after the critical micelle concentration (CMC). These theoretical arguments are used to interpret recent experimental results of Yu and collaborators on EISA experiments on Silica/PS-PEO systems.
In exploring the question of how humans reason in ambiguous situations or in the absence of complete information, we stumbled onto a body of knowledge that addresses issues beyond the original scope of our effort. We have begun to understand the importance that philosophy, in particular the work of C. S. Peirce, plays in developing models of human cognition and of information theory in general. We have a foundation that can serve as a basis for further studies in cognition and decision making. Peircean philosophy provides a foundation for understanding human reasoning and capturing behavioral characteristics of decision makers due to cultural, physiological, and psychological effects. The present paper describes this philosophical approach to understanding the underpinnings of human reasoning. We present the work of C. S. Peirce, and define sets of fundamental reasoning behavior that would be captured in the mathematical constructs of these newer technologies and would be able to interact in an agent type framework. Further, we propose the adoption of a hybrid reasoning model based on his work for future computational representations or emulations of human cognition.
This article summarizes information related to the automated course of action (COA) development effort. The information contained in this document puts the COA effort into an operational perspective that addresses command and control theory, as well as touching on the military planning concept known as effects-based operations. The sections relating to the COA effort detail the rationale behind the functional models developed and identify technologies that could support the process functions. The functional models include a section related to adversarial modeling, which adds a dynamic to the COA process that is missing in current combat simulations. The information contained in this article lays the foundation for building a unique analytic capability.
This report is an update to previous ''smart gun'' work and the corresponding report that were completed in 1996. It incorporates some new terminology and expanded definitions. This effort is the product of an open source look at what has happened to the ''smart gun'' technology landscape since the 1996 report was published.
The Comprehensive Test Ban Treaty of 1996 banned any future nuclear explosions or testing of nuclear weapons and created the CTBTO in Vienna to implement the treaty. The U.S. response to this was the cessation of all above and below ground nuclear testing. As such, all stockpile reliability assessments are now based on periodic testing of subsystems being stored in a wide variety of environments. This data provides a wealth of information and feeds a growing web of deterministic, physics-based computer models for assessment of stockpile reliability. Unfortunately until 1996 it was difficult to relate the deterministic materials aging test data to component reliability. Since that time we have made great strides in mathematical techniques and computer tools that permit explicit relationships between materials degradation, e.g. corrosion, thermo-mechanical fatigue, and reliability. The resulting suite of tools is known as CRAX and the mathematical library supporting these tools is Cassandra. However, these techniques ignore the historical data that is also available on similar systems in the nuclear stockpile, the DoD weapons complex and even in commercial applications. Traditional statistical techniques commonly used in classical re liability assessment do not permit data from these sources to be easily included in the overall assessment of system reliability. An older, alternative approach based on Bayesian probability theory permits the inclusion of data from all applicable sources. Data from a variety of sources is brought together in a logical fashion through the repeated application of inductive mathematics. This research brings together existing mathematical methods, modifies and expands those techniques as required, permitting data from a wide variety of sources to be combined in a logical fashion to increase the confidence in the reliability assessment of the nuclear weapons stockpile. The application of this research is limited to those systems composed of discrete components, e.g. those that can be characterized as operating or not operating. However, there is nothing unique about the underlying principles and the extension to continuous subsystem/systems is straightforward. The framework is also laid for the consideration of systems with multiple correlated failure modes. While an important consideration, time and resources limited the specific demonstration of these methods.