Publications

High pressure Hugoniot and release equation of state data are provided for samples from three Nevada Test Site rock units. These are the MC-2 and MC-3 members of the P-Tunnel (Paintbrush) Tuff and the N-Tunnel (Tunnel Bed) Tuff. The technique used provides continuous release trajectories from the Hugoniot pressure down to approximately half of the Hugoniot pressure. Hugoniot and release results for the MC-2 and MC-3 members are very similar, while the Hugoniot of the N-Tunnel Tuff is somewhat stiffer, consistent with the higher density of this tuff as tested. The materials were tested at less than full saturation; correcting for this tends to narrow the difference in the properties of the two rock types sufficiently that the data do not provide a basis for predicting significantly different groundshock properties of the three units, leaving unexplained the anomalously high groundshock attenuation observed in the Mission Cyber event (performed in the MC-2 unit of the Paintbrush tuff). 26 refs., 61 figs., 9 tabs.

During rapid solidification, nonequilibrium interface kinetics alter the predictions of the Mullins-Sekerka theory for the stability of a planar interface against cellular breakdown. The velocity-dependence of the partition coefficient and of the Sn concentration at the onset of cellular breakdown have been measured during pulsed laser melting of Si--Sn alloys. The Mullins-Sekerka theory is modified by inserting a velocity-dependent partition coefficient and a velocity-dependent slope of the kinetic liquids,'' both of which are extracted from the Continuous Growth Model for interface kinetics. These nonequilibrium interface kinetic effects increase the predicted critical concentration for cellular breakdown by two orders of magnitude for Sn in Si, and account fairly well for the experimental results. 34 refs., 3 figs.

Several models of runaway electron generation during a disruption are described and applied to the problem of determining the radiation loss and energy limit of runaway electrons. In particular the prediction of orbits and energy limits for proposed ITER design are discussed. It was found that resonance between the electron gyrofrequency and the fundamental ripple frequency can lead to large synchrotron radiation losses and create an upper bound on runaway energy. Interactions with the second harmonic of the ripple field are very sensitive to ripple amplitude and may lead to a further reduction in runaway energy. In ITER this effect can limit the runaway energy to values of 270 MeV. A lump circuit model of the plasma can be used to determine the coupled interactions of the runaway currents with the plasma and control circuit currents. Depending on what is assumed about the perpendicular energy of the runaway electrons. Maximum values of runaway energy predicted for ITER are in the range of 35 to 120 MeV. 4 refs., 15 figs.

A bilateral teleoperation system consists of a local master manipulator and a remotely located slave manuipulator. Generalized velocity commands are sent forward from the master to the slave, and generalized force/torque information is reflected'' back from the slave to the master. Often there is a transmission delay incurred when communicating between the two subsystems which causes instability in the bilateral teleoperator. Recently, a solution for this instability problem was found, based on mimicking the behavior of a lossless transmission line. Although this solution provides steady-state force and velocity tracking, it does not provide steady-state force and position tracking, as is desired for bilateral teleoperation. In this paper a modification is given to the basic control law which overcomes this difficulty. 13 refs., 6 figs., 1 tab.

This document serves as the proceedings for the annual project review meeting held by Sandia's Photovoltaic Cell Research Division and Photovoltaic Technology Division. It contains information supplied by each organization making a presentation at the meeting, which was held August 7 through 9, 1990 at the Sheraton Hotel in Albuquerque, New Mexico. Sessions were held to discuss national photovoltaic programs, one-sun crystalline silicon cell research, concentrator silicon cell research, concentrator 3-5 cell research, and concentrating collector development.

The Center for Compound Semiconductor-Technology (CCST)at Sandia National Laboratories encompasses the full range of required activities--theoretical and experimental solid-state physics, materials science, crystal growth, device design, and fabrication--to develop the next generation of electronic and optoelectronic devices. Semiconductor electronics are vital to the communications and computer industries and to the nation's defense. Compound semiconductors offer very high-speed electronics and integrated optical and electronic capabilities not available with silicon, and will underlie future electronic, optoelectronic, and photonic technologies. The purpose of the CCST is to perform collaborative research generic to electronic and optoelectronic technologies in compound semiconductors. The CCST also includes related research in high-temperature superconducting electronics and hybrid superconductor-semiconductor devices. Facilities in the CCST include extensive molecular-beam epitaxy and metal-organic chemical vapor deposition crystal growth capabilities, a 400-keV ion implanter, and a new 3700 net square foot, class 1000/100 clean room with state-of-the-art processing equipment. Addition of an electron-beam lithography system to permit fabrication of devices with feature sizes below 100 nm is planned for the near future.

The near-field, explosive dispersal of a liquid into air has been explored using a combination of analytical and numerical models. The near-field flow regime is transient, existing only as long as the explosive forces produced by the detonation of the burster charge dominate or are approximately equal in magnitude to the aerodynamic drag forces on the liquid. The near-field model provides reasonable initial conditions for the far-field model, which is described in a separate report. The near-field model consists of the CTH hydrodynamics code and a film instability model. In particular, the CTH hydrodynamics code is used to provide initial temperature, pressure, and velocity fields, and bulk material distribution for the far-field model. The film instability model is a linear stability model for a radially expanding fluid film, and is used to provide a lower bound on the breakup time and an upper and lower bound on the initial average drop diameter for the liquid following breakup. Predictions of the liquid breakup time and the initial arithmetic average drop diameter from the model compare favorably with the sparse experimental data. 26 refs., 20 figs., 8 tabs.

This report highlights Sandia National Laboratories' work in the following areas: photometrics and optical development; still and time-lapse photography; real-time motion photography; high-speed photography; image-motion photography; schlieren photography; ultra-high-speed photography; electronic imaging; shuttered video and high-speed video; infrared imaging radiometry; exoatmospheric photography and videography; microdensitometry and image analysis; and optical system design and development.

This report describes reference concepts for a hydrogen-oxygen combustion, turboalternator power system that supplies power during battle engagement to a space-based, ballistic missile defense platform. All of the concepts are open''; that is, they exhaust hydrogen or a mixture of hydrogen and water vapor into space. We considered the situation where hydrogen is presumed to be free to the power system because it is also needed to cool the platform's weapon and the situation where hydrogen is not free and its mass must be added to that of the power system. We also considered the situation where water vapor is an acceptable exhaust and the situation where it is not. The combination of these two sets of situations required four different power generation systems, and this report describes each, suggests parameter values, and estimates masses for each of the four. These reference concepts are expected to serve as a baseline'' to which other types of power systems can be compared, and they are expected to help guide technology development efforts in that they suggest parameter value ranges that will lead to optimum system designs. 7 refs., 18 figs., 5 tabs.

This report covers the development of improved assembly processes for the Quartz Digital Accelerometer cantilever. In this report we discuss improved single-assembly tooling, the development of tooling and processes for precision application of polyimide adhesive, the development of the wafer scale assembly procedure, and the application of eutectic bonding to cantilever assembly. 2 refs., 17 figs.

A computer code, PREGO, has been developed to perform calculations for three related problems: reflection of an acoustic wave against a layered viscoelastic medium: (water/medium); transmission of an acoustic wave through such a medium (water/medium/water); and radiation of an acoustic wave through such a medium: (medium/water). This code draws an experience gained in writing and using a predecessor code, IMPEDE, which was devised to calculate the steady state reflection of an acoustic wave impinging on a layered substrate of elastic or viscoelastic materials. That code employed a finite element formulation to discretize the complex-valued, second order ordinary differential equations for monochromatic steady state acoustics. The principles of numerical analysis that underlie PREGO are different and less subject to discretization error than those used in IMPEDE. The formulation used in PREGO is similar to that of higher dimensional boundary integral formulations in that it uses closed form expressions for the complex velocity fields in each layer, given in terms of the velocities at the boundary of that layer. The solutions for each layer are coupled together by requiring that stresses and velocities be continuous across interfaces. 5 refs., 4 figs.

A performance assessment methodology has been developed for use by the US Nuclear Regulatory Commission in evaluating license applications for low-level waste disposal facilities. This report provides a summary of background reports on the development of the methodology and an overview of the models and codes selected for the methodology. The overview includes discussions of the philosophy and structure of the methodology and a sequential procedure for applying the methodology. Discussions are provided of models and associated assumptions that are appropriate for each phase of the methodology, the goals of each phase, data required to implement the models, significant sources of uncertainty associated with each phase, and the computer codes used to implement the appropriate models. In addition, a sample demonstration of the methodology is presented for a simple conceptual model. 64 refs., 12 figs., 15 tabs.

Glass-to-metal seals are an integral part of many electronic components. When seals are formed at elevated temperatures and cooled to room temperature, residual stresses are generated by the unequal thermal contractions of the constituent materials. The combination of high stress and low fracture resistance of glass makes it extremely difficult to design and build hermetic glass-to-metal seals. Rigorous and robust stress analyses must incorporate the complex and coupled changes in volumetric strain and stress relaxation which occur as glass passes through the liquid/solid temperature regime. The phenomenological behavior of glass can be modeled viscoelastically. The theory and numerical discretization of the viscoelastic equations is presented for use in finite element programs. Vectorizable integration schemes are derived for both the traditional hereditary integrals of viscoelasticity and the equivalent rate forms of the equations. The general behavior of glass is discussed and related to the viscoelastic model. Solutions to discretized viscoelastic equations are applied to an example problem and compared to results obtained from experimental data. The viscoelastic model of glass provides a new capability to analyze and design actual manufacturing processes by predicting, a priori, the effects of temperature history on the residual stress state.

Kerberos is a network user authentication system that was recently developed at the Massachusetts Institute of Technology (MIT). It has been adopted by Sandia National Laboratories, Albuquerque, for use in the Secure Supercomputing Network (SSN) which is currently under development. FTP and TELNET are two of the most important network applications for the SSN, which is to use the TCP/IP protocol suite. FTP provides capabilities for bulk file transfer between nodes and TELNET provides a remote interactive login capability across the network. This design describes how authentication is currently performed in FTP and TELNET using clear text passwords and proposes a method for modifying them to use Kerberos authentication.

When the boundary integral equation method is applied to exterior acoustics problems, singularities occur in the resulting algebraic equations at various frequencies associated with the eigenvalues of an interior problem. These frequencies are referred to as forbidden,'' and various methods have been devised to overcome the computational difficulties presented at these frequencies. The work presented here is an extension to the CHIEF method in that higher derivatives, in addition to the function itself, are constrained to be zero at selected points in the interior domain. Whereas the relative success of either method depends on the quantity and selection of interior points, the SuperCHIEF method requires fewer interior points and is less sensitive to point selection, resulting in improved robustness without significant increase in computational complexity. 3 refs., 14 refs.

Massively parallel computers and computer networks are beginning to appear as an integral part of the scientific computing workplace. This report documents the goals and the corresponding development plan of the massively parallel project of Departments 1530 and 1420. The main goal of the project is to provide a clear understanding of the issues and difficulties involved in bringing the current production hydrocode CTH to the state of being portable to a number of currently available parallel computing architectures. In the process of this research, various working versions of the code will be produced. 6 refs., 6 figs.

This report examines effects of aging on cables, connections, and containment electrical penetration assemblies (EPAs). Aging is defined as the cumulative effects that occur to a component with the passage of time. If unchecked, these effects can lead to a loss of function and a potential impairment of plant safety. This study includes a review of component usage in nuclear power plants; a review of some commonly used components and their materials of construction; a review of the stressors that the components might be exposed to in both normal and accident environments; a compilation and evaluation of industry failure data; a discussion of component failure modes and causes; and a brief description of current industry testing and maintenance practices. 51 refs., 12 figs., 12 tabs.

CEPXS/ONELD is a discrete ordinates code package for one-dimensional coupled electron-photon transport over the energy range of 100 MeV to 1.0 keV. In this Results Guide, CEPXS/ONELD predictions are compared to the predictions of Monte Carlo codes and to experiment. These comparisons are made for a variety of quantities, including energy deposition, charge deposition and electron current spatial profiles as well as electron and photon spectra. Sensitivity studies are presented that show how the numerical approximations of CEPXS/ONELD can affect the accuracy of predictions. Guidelines for the efficient and accurate use of the code package are given. All examples involve one-dimensional planar geometry and non-adjoint transport. 35 refs.

Charge exchange results in the transfer of momentum from an ion to a neutral atom, thus it is equivalent to a slowing down mechanism for ions. This might be helpful in IFR propagation of relativistic electron beams. The effect of charge exchange on the ion hose instability and channel expansion after beam passage is investigated in this report. For parameters of interest to current experiments, it is found that the effect on growth of the ion hose instability is insignificant, but there is significant reduction in the energy of the expanding ions after passage of the electron beam. 5 refs., 5 figs.

The nickel/hydrogen battery was developed in the 1970s as an energy storage subsystem for commercial communication satellites. The advantages offered by nickel/hydrogen batteries, including long life, low maintenance and high reliability, make it very attractive for terrestrial applications such as stand-alone photovoltaic systems. The major drawback to the wider use of the nickel/hydrogen battery is its high initial cost. Sandia National Laboratories has directed cost-shared contracts at Comsat Laboratories and Johnson Controls, Inc. to reduce the cost, and a battery consisting of prismatic cells in a common pressure vessel has evolved. Contract deliverables include cells and batteries that are evaluated at Sandia. This report summarizes the results over the past two years of both cycle and solar testing. 6 refs., 12 figs., 5 tabs.

This report will present the development history, characterization data and the qualification activities for the SA3646. This device is manufactured by SEEQ Technology Inc., with part number LM28C256-250/B and is a 256K Electricity Erasable Programmable Read Only Memory (EEPROM). 14 refs., 25 figs.

A computational fluids dynamics scheme is presented to solve the unsteady Thin-Layer Navier-Stokes (TLNS) equations over a blunt body at high altitude, high Mach number atmospheric reentry flow conditions. This continuum approach is directed to low density hypersonic flows by accounting for non-zero bulk viscosity effects in near frozen flow conditions. The TLNS equations are solved over an axisymmetric body at zero incidence relative to the free stream. The time dependent axisymmetric governing equations are transformed into a computational plane, then cast into weak conservative form and solved using a first-order fully implicit scheme in time with second-order flux vector splitting for spatial derivatives. The physical domain is defined over representative sphere and sphere/cone geometries using a body-fitted clustered algebraic grid within a fixed domain (i.e., shock capturing). At the present time, nonequilibrium thermo-chemistry effects are not modeled. Catalytic wall, ionization and radiation effects are also excluded from the current analysis. However, the significant difference from previous studies is the inclusion of the capability to model non-zero bulk viscosity effects. The importance of bulk viscosity is reviewed and blunt body flow field solutions are presented to illustrate the potential contribution of this phenomena at high altitude hypersonic conditions. The current technique is compared with experimental data and other approximate continuum solutions. A variety of test cases are also presented for a wide range of free stream Mach conditions.

This report documents the development and testing of the 375492, a Schottky barrier diode die, similar to the Hewlett-Packard 5082-0094. 18 figs., 4 tabs.

This document contains the technical specifications and implementation details for the Product Evaluation Management Information System (PREMIS) Version 1.1.2. This document does not include the requirements analysis or design information and is not intended as a user's guide. The INGRES Applications-by-Forms (ABF) software development tool was used to specify and define the modules and screens which comprise the PREMIS application. Several external procedures are called by the ABF procedures; these have been written in VAX/VMS DCL (Digital Command Language) and SQL (Standard Query Language). These specifications together with the PREMIS information model and corresponding database definition constitute the PREMIS Version 1.1.2 technical specification and implementation description presented herein.

The feasibility of performing, numerous spent fuel cask operations using fully integrated robotic systems is under evaluation. Using existing technology, operational and descriptive software and hardware in the form of robotic end effectors are being designed in conjunction with interfacing cask components. A robotic radiation and contamination survey system has been developed and used on mock-up cask hardware to evaluate the impact of such fully automated operations on cask design features and productivity. Based on experience gained from the survey system, numerous health physics operations can be reliably performed with little human intervention using a fully automated system. Such operations can also significantly reduce time requirements for cask-receiving operations. 7 refs., 51 figs., 6 tabs.