Publications

As part of the United States Department of Energy`s (DOE) Comprehensive Test Ban Treaty (CTBT) research and development effort, a Knowledge Base is being developed. This Knowledge Base will store the regional geophysical research results as well as geographic contexual information and make this information available to the Automated Data Processing (ADP routines) as well as human analysts involved in CTBT monitoring. This paper focuses on the initial development of a browser prototype to be used to interactively examine the contents of the CTBT Knowledge Base. The browser prototype is intended to be a research tool to experiment with different ways to display and integrate the datasets. An initial prototype version has been developed using Environmental Systems Research Incorporated`s (ESRI) ARC/INFO Geographic Information System (GIS) product. The conceptual requirements, design, initial implementation, current status, and future work plans are discussed. 4 refs., 2 figs.

Wireless Asynchronous Transfer Mode (WATM) networks pose new traffic management problems. One example is the effect of user mobility on Usage Parameter Control (UPC). If the UPC algorithm resets after each handoff between wireless-cells, then users can cheat on their traffic contract. This paper derives explicit relationships between a user`s traffic parameters (Peak Cell Rate, Sustained Cell Rate and Maximum Burst Size), their transit time per wireless-cell, their maximum sustained cheating-rate and the Generic Cell Rate Algorithm`s (GCRA`s) Limit (L) parameter. It also shows that the GCRA can still effectively police Constant Bit Rate (CBR) traffic, but not some types of realistic Variable Bit Rate (VBR) traffic.

Recent discoveries in the field of conjugated polymers in environmental stability, regiochemical regularity, and electrical conductivity, particularly of polythiophene and polyaniline, have intensified interest in device applications. Present or anticipated applications include development of electrical circuitry on a molecular scale, as well as conducting and semiconducting materials for a variety of applications including thin film transistors and batteries. The authors have investigated a series of compounds comprising conjugated segments coupled to photochromic elements. The photochromic reaction in these compounds reversibly alters the conjugation length and provides a mechanism for switching both the electrical and optical properties of these materials. The authors are currently investigating the nature and scope of this switching mechanism and preparing extended materials that take advantage of this novel form of switching behavior. Preparation and photochromic behavior of several of these materials are described.

Geotechnical characterization of the Main Drift of the Exploratory Studies Facility was based on borehole data collected in site characterization drilling and on scanline rock mass quality data collected during the excavation of the North Ramp. The Main Drift is the planned 3,131-m near-horizontal tunnel to be excavated at the potential repository horizon for the Yucca Mountain Site Characterization Project. Main Drift borehole data consisted of three holes--USW SD-7, SD-9, and SD-12--drilled along the tunnel alignment. In addition, boreholes USW UZ-14, NRG-6, and NRG-7/7A were used to supplement the database on subsurface rock conditions. Specific data summarized and presented included lithologic and rock structure core logs, rock mechanics laboratory testing, and rock mass quality indices. Cross sections with stratigraphic and thermal-mechanical units were also presented. Topics discussed in the report include geologic setting, geologic features of engineering and construction significance, anticipated ground conditions, and the range of required ground support. Rock structural and rock mass quality data have been developed for each 3-m interval of core in the middle nonlithophysal stratigraphic zone of the Topopah Spring Tuff Formation. The distribution of the rock mass quality data in all boreholes used to characterize the Main Drift was assumed to be representative of the variability of the rock mass conditions to be encountered in the Main Drift. Observations in the North Ramp tunnel have been used to project conditions in the lower lithophysal zone and in fault zones.

The shaft seal system for the Waste Isolation Pilot Plant (WIPP) must provide a barrier to the migration of fluids within the shafts to prevent the release of contaminants to the accessible environment. To investigate the performance of the shaft seal system, a set of fluid flow performance models was developed based upon the physical characteristics of the WIPP shaft seal system and the surrounding geologic media. This paper describes the results of a numerical model used to investigate the long-term potential for brine migration through the shaft seal system. Modeling results demonstrate that the WIPP shaft seal system will effectively limit brine migration within the repository shafts.

The authors report selectivity and sensitivity for 97-MHz SAW (surface acoustic wave) sensors functionalized with (COO{sup {minus}}){sub 2}/Cu{sup 2+}-terminated, organomercaptan-based, self-assembled monolayers (SAMs). Responses were obtained as a function of SAM formation time on thin Au films of controlled grain size. The authors find that the SAM films (1) preferentially adsorb classes of organic analytes according to simple chemical interaction concepts, (2) reversibly adsorb multilayers of some analytes well below their saturation vapor pressure, (3) adsorb more diisopropylmethylphosphonate (DIMP) at a given partial pressure as SAM solution-phase adsorption time increases, and (4) adsorb more DIMP at a given partial pressure as the grain size of the supporting Au film decreases.

Crushed salt from the host Salado Formation is proposed as a sealing material in one component of a multicomponent seal system design for the shafts of the Waste Isolation Pilot Plant (WIPP), a mined geological repository for storage and disposal of transuranic radioactive wastes located near Carlsbad, New Mexico. The crushed salt will be compacted and placed at a density approaching 90% of the intact density of the host Salado salt. Creep closure of the shaft will further compact the crushed salt over time, thereby reducing the crushed-salt permeability from the initial state and creating an effective long-term seal. A structural model and a fluid flow model have been developed to provide an estimate of crushed-salt reconsolidation rate as a function of depth, time, and pore pressure. Model results are obtained in terms of crushed-salt permeability as a function of time and depth within the salt column. Model results indicate that average salt column permeability will be reduced to 3.3 {times} 10{sup {minus}20} m{sup 2} in about 100 years, which provides for an acceptable long-term seal component.

Underground excavations produce damaged zones surrounding the excavations which have disturbed hydrologic and geomechanical properties. Prediction of fluid flow in these zones must consider both the mechanical and fluid flow processes. Presented here is a methodology which utilizes a mechanical model to predict damage and disturbed rock zone (DRZ) development around the excavation and then uses the predictions to develop time-dependent DRZ porosity relationships. These relationships are then used to adjust the porosity of the DRZ in the fluid flow model based upon the time and distance from the edge of the excavation. The application of this methodology is presented using a site-specific example from the Waste Isolation Pilot Plant, a US Department of Energy facility in bedded salts being evaluated for demonstration of the safe underground disposal of transuranic waste from US defense-related activities.

A specially designed minipermeameter test system, termed the Multisupport Permeameter (MSP), has been developed for direct physical investigation of permeability upscaling. The unique feature of this instrument is its ability to acquire permeability data at multiple sample supports subject to consistent boundary conditions and flow geometries. This device has been employed to physically investigate the permeability upscaling characteristics of a block of Berea Sandstone. Results reveal a number of consistent and distinct trends relating key summary statistics to changes in sample support. Comparisons are drawn between trends in the sample mean measured on the Berea Sandstone and that predicted by three theoretical upscaling models representing three common but different approaches to modeling permeability upscaling.

This report presents the preliminary results of an analysis of China`s water resources, part of an effort undertaken by the National Intelligence Council Medea scientists to improve the understanding of future food production and consumption in the People`s Republic of China. A dynamic water model was developed to simulate the hydrological budgetary processes in five river drainage basins located in northeastern, central, and southern China: the Chang Jiang (Yangtse River), Huanghe (Yellow River), Haihe, Huaihe, and Liaohe. The model was designed to assess the effects of changes in urban, industrial, and agricultural water use requirements on the availability of water in each basin and to develop estimates of the water surpluses and/or deficits in China through the year 2025. The model imposes a sustainable yield constraint, that is, groundwater extraction is not allowed to exceed the sustainable yield; if the available water does not meet the total water use requirements, a deficit results. An agronomic model was also developed to generate projections of the water required to service China`s agricultural sector and compare China`s projected grain production with projected grain consumption requirements to estimate any grain surplus and/or deficit. In future refinements, the agronomic model will interface directly with the water model to provide for the exchange of information on projected water use requirements and available water. The preliminary results indicate that the Chang Jiang basin will have a substantial surplus of water through 2025 and that the Haihe basin is in an ongoing situation. The agricultural water use requirements based on grain production indicate that an agricultural water deficit in the Haihe basin begins before the onset of the modeling period (1980) and steadily worsens through 2025. This assumption is confirmed by reports that groundwater mining is already under way in the most intensely cultivated and populated areas of northern China.

Staff of the Telemetry Technology Development Department (2664) have, in support of the U.S. Interior Department Mineral Management Services (MMS), developed and deployed the Seafloor Earthquake Measurement System IV (SEMS IV). The result of this development project is a series of three fully operational seafloor seismic monitor systems located at offshore platforms: Eureka, Grace, and Irene. The instrument probes are embedded from three to seven feet into the seafloor and hardwired to seismic data recorders installed top side at the offshore platforms. The probes and underwater cables were designed to survive the seafloor environment with an operation life of five years. The units have been operational for two years and have produced recordings of several minor earthquakes in that time. Sandia Labs will transfer operation of SEMS IV to MMS contractors in the coming months. 29 figs., 25 tabs.

SANTOS is a finite element program designed to compute the quasistatic, large deformation, inelastic response of two-dimensional planar or axisymmetric solids. The code is derived from the transient dynamic code PRONTO 2D. The solution strategy used to compute the equilibrium states is based on a self-adaptive dynamic relaxation solution scheme, which is based on explicit central difference pseudo-time integration and artificial mass proportional damping. The element used in SANTOS is a uniform strain 4-node quadrilateral element with an hourglass control scheme to control the spurious deformation modes. Finite strain constitutive models for many common engineering materials are included. A robust master-slave contact algorithm for modeling sliding contact is implemented. An interface for coupling to an external code is also provided. 43 refs., 22 figs.

In order to probe the response of silicone door gasket materials to a postulated severe accident in an Italian nuclear power plant, compression stress relaxation (CSR) and compression set (CS) measurements were conducted under combined radiation (approximately 6 kGy/h) and temperature (up to 230{degrees}C) conditions. By making some reasonable initial assumptions, simplified constant temperature and dose rates were derived that should do a reasonable job of simulating the complex environments for worst-case severe events that combine overall aging plus accidents. Further simplification coupled with thermal-only experiments allowed us to derive thermal-only conditions that can be used to achieve CSR and CS responses similar to those expected from the combined environments that are more difficult to simulate. Although the thermal-only simulations should lead to sealing forces similar to those expected during a severe accident, modulus and density results indicate that significant differences in underlying chemistry are expected for the thermal-only and the combined environment simulations. 15 refs., 31 figs., 15 tabs.

The U.S. Department of Transportation Research & Special Programs Administration (DOT-RSPA) has sponsored a project at Sandia National Laboratories to evaluate the protection provided by current packagings used for truck and rail transport of materials that have been classified as Poison Inhalation Hazards (PIH) and to recommend performance standards for these PIH packagings. Hazardous materials span a wide range of toxicity and there are many parameters used to characterize toxicity; for any given hazardous material, data are not available for all of the possible toxicity parameters. Therefore, it was necessary to select a toxicity criterion to characterize all of the PIH compounds (a value of the criterion was derived from other parameters in many cases) and to calculate their dispersion in the event of a release resulting from a transportation accident. Methodologies which account for material toxicity and dispersal characteristics were developed as a major portion of this project and applied to 72 PIH materials. This report presents details of the PIH material toxicity comparisons, calculation of their dispersion, and their classification into five severity categories. 16 refs., 5 figs., 7 tabs.

A restrictive flow orifice (RFO) can be used to limit the uncontrolled release of system media upon component or line failure in a gas handling system and can thereby enhance the system safety. This report describes a new RFO product available from the Swagelok Companies and specifies the gas flow characteristics of this device. A family of four different sizes of RFO devices is documented.

High strength, hermetic braze joints between ceramic components have been produced using high energy electron beams. With a penetration depth into a typical ceramic of {approximately}1 cm for a 10 MeV electron beam, this method provides the capability for rapid, transient brazing operations where temperature control of critical components is essential. The method deposits energy directly into a buried joint, allowing otherwise inaccessible interfaces to be brazed. Because of transient heating, higher thermal conductivity, lower heat capacity, and lower melting temperature of braze metals relative to the ceramic materials, a pulsed high power beam can melt a braze metal without producing excessive ceramic temperatures. We have demonstrated the feasibility of this process related to ceramic coupons as well as ceramic and glass tubes. The transient thermal response was predicted, using as input the energy absorption predicted from the coupled electron-photon transport analysis. The joining experiments were conducted with an RF Linac accelerator at 10-13 MV. The repetition rate of the pulsed beam was varied between 8 and 120 Hz, the average beam current was varied between 8 and 120 microamps, and the power was varied up to 1.5 kW. These beam parameters gave a beam power density between 0.2 to 2 kW/cm{sup 2}. The duration of the joining runs varied from 5 to 600 sec. Joining experiments have provided high strength between alumina - alumina and alumina - cermet joints in cylindrical geometry. These joints provided good hermetic seals. A series of tests was conducted to determine the minimum beam power and exposure time for producing, a hermetic seal.

Burn-in effects are used to demonstrate the potential impact of thermally activated aging effects on functional and parametric radiation hardness. These results have implications on hardness assurance testing. Techniques for characterizing aging effects are proposed.

Sandia has developed PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack. and MITLs on PBFA II with hardware of a new design. The PBFA-Z accelerator was designed to deliver 20 MA to a 15-mg z-pinch load in 100 ns. The accelerator was modeled using circuit codes to determine the time-dependent voltage and current waveforms at the input and output of the water lines, the insulator stack, and the MITLs. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack consists of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stacks was evaluated using IVORY, a 2-D PIC code. This paper will describe the insulator stack design, present the results of the ELECTRO and IVORY analyses, and show the results of the stack measurements.

In recent years, technological advances have significantly enhanced the capability to produce milli- and micro-sized components which may be incorporated into the design of small, less costly, reproducible and more reliable nuclear weapons components. Two promising micro-scale processing technologies are Silicon surface micromachining (SMM), a process derived from microelectronics fabrication, and LIGA, a process involving electrodeposition of metals into a polymeric mask containing very fine, sharp features. Complicated SMM structures with micron sized features such as microengines, gears and pop-up mirrors have already been successfully developed. As part of an overall broad effort to develop mechanical test capability of millisized and microsized structures, a mechanical test system has been designed and assembled with the primary goal of characterizing the mechanical properties of LIGA synthesized structures and materials. The current system utilizes many off-the-shelf items including an MTS 3,000 pound 1.0 inch travel hydraulic actuator and an Interface 100 pound load cell. Load, stroke and displacement control is provided by an MTS TestStar system and two 0.100 inch LVDT displacement gages situated in a parallel arrangement at the specimen. Load resolution is on the order of 50 {micro} oz. and displacement resolution less than 45 {micro} inch. The system can test dynamically up to 100 hz at 0.005 inch actuator displacement and loads of 100 lb., statically at up to 250 lb. (limited by the load cell). The scope and flexibility of the microscale test system extends far beyond simply testing LIGA synthesized parts. A detailed description of the machine and a diverse set of results are presented in this report.

Commercial airframes exceeding 20 service years often develop crack and corrosion flaws. Bonded composite doublers offer a cost effective method to safely extend aircraft lives. The Federal Aircraft Authority (FAA) has completed a project to introduce composite doubler repair technology to the commercial aircraft industry. Instead of riveting steel or aluminum plates for repair, a single composite doubler may be bonded to the damaged structure. Adhesive bonding eliminates stress concentrations caused by fastener holes. Composites are readily formed into complex shapes for repairing irregular components. Also, composite doublers can be tailored to meet specific anisotropy needs, eliminating structural stiffening in directions other than those required. Other advantages include corrosion resistance, a high strength-to-weight ratio, and potential time savings in installation. One phase of this study developed general methodologies and test programs to ensure proper performance of the technique. A second phase focused on reinforcement of an L-1011 door frame, and encompassed all lifetime tasks such as design, analysis, installation, and nondestructive inspection. This paper overviews the project and details the activities conducted to gain FAA approval for composite doubler use. Structural tests evaluated the damage tolerance and fatigue performance of composite doublers while finite element models were generated to study doubler design issues. Nondestructive inspection procedures were developed and validated using full-scale test articles. Installation dry-runs demonstrated the viability of applying composite doublers in hangar environments. The project`s documentation package was used to support installation of a Boron-Epoxy composite repair on a Delta Air Lines L-1011 aircraft. A second product of the results is a Lockheed Service Bulletin which allows the door corner composite doubler to be installed on all L-1011 aircraft. 9 refs., 10 figs., 2 tabs.

A coordinated program in inspection system research was started at the Federal Aviation Administration (FAA) Technical Center in 1990 as part the National Aging Aircraft Research Program. The primary objectives of the Inspection Systems Research Initiative are to act in concert with other government agencies and private industry to develop improved inspection techniques to address specific airframe and engine inspection problems and to evaluate and validate existing and emerging inspection systems. Advanced conventional technologies, emerging technologies, or combinations of technologies are investigated for their ability to accurately and reliably detect cracks, disbonds, corrosion, and other damage. This paper will present an overview of the FAA inspection system research initiative with special focus on the successes through validation and technology transfer.

Goal was Assembly Test Chips (ATCs) which could be used for evaluating plastic encapsulation technologies. Circuits were demonstrated for measuring Au-Al wirebond and Al metal corrosion failure rates during accelerated temperature and humidity testing. The test circuits on the ATC02.5 chip were very sensitive to extrinsic or processing induced failure rates. Accelerated aging experiments were conducted with unpassivated triple track Al structures on the ATC02.6 chip; the unpassivated tracks were found to be very sensitive to particulate contamination. Some modifications to existing circuitry were suggested. The piezoresistive stress sensing circuitry designed for the ATC04 test chip was found suitable for determining the change in the state of mechanical stress at the die when both initial and final measurements were made near room temperature (RT). Attempt to measure thermal stress between RT and a typical polymer glass transition temperature failed because of excessive die resistor- substrate leakage currents at the high temperature end; suitable circuitry changes were developed to overcome this problem. One temperature and humidity experiment was conducted with Sandia developed static radom access memory parts to examine non-corrosion CMOS failures; this objective was not achieved, but corrosion failure at the metal to Si contacts on the die surface could be detected. This 2-year effort resulted in new designs for test circuits which could be used on an advanced ATC for reliability assessment in Defense Programs electronics development projects.

There is a need for hypersonic wind-tunnel testing at about mach 10 and above using natural air and simulating temperatures and pressures which are prototypic of flight at 50 km altitude or below. With traditional wind-tunnel techniques, gas cooling during expansion results in exit temperatures which are too low. Miles, et al., have proposed overcoming this difficulty by heating the air with a laser beam as it expands in the wind-tunnel nozzle. This report discusses an alternative option of using a high-power electron beam to heat the air as it expands. In the e-beam heating concept, the electron beam is injected into the wind-tunnel nozzle near the exit and then is guided upstream toward the nozzle throat by a strong axial magnetic field. The beam deposits most of its power in the dense air near the throat where the expansion rate is greatest. A conceptual design is presented for a large-scale system which achieves Mach 14 for 0.1 seconds with an exit diameter of 2.8 meters. It requires 450 MW of electron beam power (5 MeV at 90 A). The guiding field is 500 G for most of the transport length and increases to 100 kG near the throat to converge the beam to a 1.0-cm diameter. The beam generator is a DC accelerator using a Marx bank (of capacitors) and a diode stack with a hot cathode. 14 refs. 38 figs., 9 tabs.

The role that drilling technology development can play in reducing the cost of geothermal power is examined. Factors contributing to the relatively high cost of geothermal drilling are discussed, and potential technology improvements that could reduce those costs are identified. Projects under way at Sandia National Laboratories to address these technology needs are summarized, and estimates are made of the potential drilling cost savings resulting from these projects.

Prior to 1989 {sup 99}Mo was produced in the US by a single supplier, Cintichem Inc., Tuxedo, NY. Because of problems associated with operating its facility, in 1989 Cintichem elected to decommission the facility rather than incur the costs for repair. The demise of the {sup 99}Mo capability at Cintichem left the US totally reliant upon a single foreign source, Nordion International, located in Ottawa Canada. In 1992 the DOE purchased the Cintichem {sup 99}Mo Production Process and Drug Master File (DMF). In 1994 the DOE funded Sandia National Laboratories (SNL) to produce {sup 99}Mo. Although Cintichem produced {sup 99}Mo and {sup 99m}Tc generators for many years, there was no requirement for process validation which is now required by the Food and Drug Administration (FDA). In addition to the validation requirement, the requirements for current Good manufacturing Practices were codified into law. The purpose of this paper is to describe the process validation being conducted at SNL for the qualification of SNL as a supplier of {sup 99}Mo to US pharmaceutical companies.