Publications

Results 91101–91200 of 96,771

Search results

Jump to search filters

Laboratory accreditation

Pettit, Richard B.

Accreditation can offer many benefits to a testing or calibration laboratory, including increased marketability of services, reduced number of outside assessments, and improved quality of services. Compared to ISO 9000 registration, the accreditation process includes a review of the entire quality system, but in addition a review of testing or calibration procedures by a technical expert and participation in proficiency testing in the areas of accreditation. Within the DOE, several facilities have recently become accredited in the area of calibration, including Sandia National Laboratories, Oak Ridge, AlliedSignal FM and T; Lockheed Martin Idaho Technologies Co., and Pacific Northwest National Lab. At the national level, a new non-profit organization was recently formed called the National Cooperation for Laboratory Accreditation (NACLA). The goal of NACLA is to develop procedures, following national and international requirements, for the recognition of competent accreditation bodies in the US. NACLA is a voluntary partnership between the public and private sectors with the goal of a test or calibration performed once and accepted world wide. The NACLA accreditation body recognition process is based on the requirements of ISO Guide 25 and Guide 58. A membership drive will begin some time this fall to solicit organizational members and an election of a permanent NACLA Board of Directors will follow later this year or early 1999.

More Details

Comparison of bulk- and surface-micromachined pressure sensors

Eaton, W.P.

Two piezoresistive micromachined pressure sensors were compared: a commercially available bulk-micromachined (BM) pressure sensor and an experimental surface-micromachined (SM) pressure sensor. While the SM parts had significantly smaller die sizes, they were outperformed in most areas by the BM parts. This was due primarily to the smaller piezoresistive gauge factor in the polysilicon piezoresistors in the SM parts compared to the single crystal strain gauge used in the BM parts.

More Details

A new method for making shallow p-type junctions

Walsh, David S.

In this paper the authors present a new method for making shallow p-type junctions in silicon by molecular ion implantation. Unlike current molecular ion implantation methods which use boron and fluorine molecules, this new method uses an element which is completely miscible in silicon. Note that fluorine is an element that saturates at a very low concentration in silicon. The compounds used in this new method are boron silicides and boron germanium molecules. These compounds have several distinct advantages including the facts that the co-element silicon (or germanium) has a very high saturation value in the silicon matrix, the co-element is massive and therefore creates more damage during implantation, and the co-element has a larger projected range than the boron. Note that the Rp for fluorine is shallower than that of Boron for a BF{sub 2} implant. Recent experiments indicate that BSi ion beams can be generated in a sputter ion source with efficiencies of 0.5% with respect to the generated Si beam. A plan to develop a new ion source that is compatible with current ion implantation systems is presented.

More Details

A review of accelerator concepts for the Advanced Hydrotest Facility

Maenchen, John E.

The Advanced Hydrotest Facility (AHF) is a facility under consideration by the Department of Energy (DOE) for conducting explosively-driven hydrodynamic experiments. The major diagnostic tool at AHF will be a radiography accelerator having radiation output capable of penetrating very dense dynamic objects on multiple viewing axes with multiple pulses on each axis, each pulse having a time resolution capable of freezing object motion ({approx}50-ns) and achieving a spatial resolution {approx}1 mm at the object. Three accelerator technologies are being considered for AHF by the DOE national laboratories at Los Alamos (LANL), Livermore (LLNL), and Sandia (SNL). Two of these are electron accelerators that will produce intense x-ray pulses from a converter target yielding a dose {approx}1,000--2,000 Rads {at} 1 meter. LLNL has proposed a 16--20 MeV, 3--6 kA linear induction accelerator (LIA) driven by FET-switched modulators driving metglas loaded cavities. SNL has proposed a 12-MeV, 40-kA Inductive Voltage Adder (IVA) accelerator based on HERMES III pulsed power technology. The third option is a 25--50-GeV proton accelerator capable of {approx}10{sup 13} protons/pulse proposed by LANL. This paper will review the current status of the three accelerator concepts for AHF.

More Details

Authenticated tracking and monitoring system (ATMS) tracking shipments from an Australian uranium mine

Schoeneman, J.L.

The Authenticated Tracking and Monitoring System (ATMS) answers the need for global monitoring of the status and location of sensitive items on a worldwide basis, 24 hours a day. ATMS uses wireless sensor packs to monitor the status of the items and environmental conditions. A receiver and processing unit collect a variety of sensor event data. The collected data are transmitted to the INMARSAT satellite communication system, which then sends the data to appropriate ground stations. Authentication and encryption algorithms secure the data during communication activities. A typical ATMS application would be to track and monitor the safety and security of a number of items in transit along a scheduled shipping route. The resulting tracking, timing, and status information could then be processed to ensure compliance with various agreements. Following discussions between the Australian Safeguards Office (ASO), the US Department of Energy (DOE), and Sandia National Laboratories (SNL) in early 1995, the parties mutually agreed to conduct and evaluate a field trial prototype ATMS to track and monitor shipments of uranium ore concentrate (UOC) from an operating uranium mine in Australia to a final destination in Rotterdam, the Netherlands, with numerous stops along the way. During the months of February and March 1998, the trial was conducted on a worldwide basis, with tracking and monitoring stations located at sites in both Australia and the US. This paper describes ATMS and the trial.

More Details

Review of enhanced vapor diffusion in porous media

Webb, Stephen W.

Vapor diffusion in porous media in the presence of its own liquid has often been treated similar to gas diffusion. The gas diffusion rate in porous media is much lower than in free space due to the presence of the porous medium and any liquid present. However, enhanced vapor diffusion has also been postulated such that the diffusion rate may approach free-space values. Existing data and models for enhanced vapor diffusion, including those in TOUGH2, are reviewed in this paper.

More Details

Modeling the effect of excavation-disturbed-zone porosity increase on groundwater inflow to an underground repository

Webb, Stephen W.

The excavation of underground radioactive waste repositories produces conditions where the repository is underpressured relative to the surrounding host rock, resulting in groundwater inflow to the repository. Groundwater has been shown to enhance gas generation from emplaced waste forms, which in turn expedites repository pressurization. Repository pressurization from waste-generated gas results in an increased driving force for dissolved radionuclide movement away from the repository. Repository excavation also produces a zone surrounding the repository having disturbed hydrologic and geomechanical properties. Within this disturbed rock zone (DRZ), intrinsic permeability and porosity change over time due to the formation of microfractures and grain boundary dilation. Additionally, elastic and inelastic changes in pore volume, driven by excavation-related stress redistribution, may cause variations in the near-field fluid pressure and fluid saturation distributions that influence groundwater flow toward the repository excavation. Increased permeability, decreased pore-fluid pressure, and partially saturated conditions within the DRZ also contribute to enhancing potential release pathways away from the repository. Freeze et al. describe an enhanced version of TOUGH2 (called TOUGH28W) and its application to model the coupled processes of gas generation, multiphase flow and geomechanical deformation at the Waste Isolation Pilot Plant (WIPP) repository. This paper describes a new application of TOUGH28W that couples time-dependent DRZ property changes with multiphase groundwater flow around an underground excavation at WIPP. The results are relevant not only to other salt repositories, but also to repositories in other geologic formations where groundwater inflow and DRZ effects are a concern.

More Details

Faster shot-record depth migrations using phase encoding

Ober, Curtis C.

Phase encoding of shot records provides a means of imaging a number of shots within a single migration. This results in a reduction in the required computation for a complete image, a reduction by the number of shots used in each individual migration, trading this increase in speed for additional noise in the resulting image. Some methods for phase encoding have been shown to limit this noise to a tolerable range when combining several shots, enabling speed ups of a factor of a few. In this paper, the authors present a use of phase encoding which allows faster imaging by an order of magnitude or more, with the additional benefit that the individual migrations can be stopped whenever the answer is good enough. This approach may ultimately render 3-D frequency-domain prestack depth migration cost effective.

More Details

Verification experiment on the downblending of high enriched uranium (HEU) at the Portsmouth Gaseous Diffusion Plant. Digital video surveillance of the HEU feed stations

Martinez, R.L.; Tolk, K.; Whiting, N.; Castleberry, K.; Lenarduzzi, R.

As part of a Safeguards Agreement between the US and the International Atomic Energy Agency (IAEA), the Portsmouth Gaseous Diffusion Plant, Piketon, Ohio, was added to the list of facilities eligible for the application of IAEA safeguards. Currently, the facility is in the process of downblending excess inventory of HEU to low enriched uranium (LEU) from US defense related programs for commercial use. An agreement was reached between the US and the IAEA that would allow the IAEA to conduct an independent verification experiment at the Portsmouth facility, resulting in the confirmation that the HEU was in fact downblended. The experiment provided an opportunity for the DOE laboratories to recommend solutions/measures for new IAEA safeguards applications. One of the measures recommended by Sandia National Laboratories (SNL), and selected by the IAEA, was a digital video surveillance system for monitoring activity at the HEU feed stations. This paper describes the SNL implementation of the digital video system and its integration with the Load Cell Based Weighing System (LCBWS) from Oak Ridge National Laboratory (ORNL). The implementation was based on commercially available technology that also satisfied IAEA criteria for tamper protection and data authentication. The core of the Portsmouth digital video surveillance system was based on two Digital Camera Modules (DMC-14) from Neumann Consultants, Germany.

More Details

Creep failure of a reactor pressure vessel lower head under severe accident conditions

Pilch, M.M.; Ludwigsen, J.S.; Chu, T.Y.; Rashid, Y.R.

A severe accident in a nuclear power plant could result in the relocation of large quantities of molten core material onto the lower head of he reactor pressure vessel (RPV). In the absence of inherent cooling mechanisms, failure of the RPV ultimately becomes possible under the combined effects of system pressure and the thermal heat-up of the lower head. Sandia National Laboratories has performed seven experiments at 1:5th scale simulating creep failure of a RPV lower head. This paper describes a modeling program that complements the experimental program. Analyses have been performed using the general-purpose finite-element code ABAQUS-5.6. In order to make ABAQUS solve the specific problem at hand, a material constitutive model that utilizes temperature dependent properties has been developed and attached to ABAQUS-executable through its UMAT utility. Analyses of the LHF-1 experiment predict instability-type failure. Predicted strains are delayed relative to the observed strain histories. Parametric variations on either the yield stress, creep rate, or both (within the range of material property data) can bring predictions into agreement with experiment. The analysis indicates that it is necessary to conduct material property tests on the actual material used in the experimental program. The constitutive model employed in the present analyses is the subject of a separate publication.

More Details

Data surety demonstrations

Herrington, Preston B.

The use of data surety within the International Monitoring System (IMS) is designed to offer increased trust of acquired sensor data at a low cost. The demonstrations discussed in the paper illustrate the feasibility of hardware authentication for sensor data and commands in a retrofit environment and a new system and of the supporting key management system. The individual demonstrations which are summarized in the paper are: (1) demonstration of hardware authentication for communication authentication in a retrofit environment; (2)demonstration of hardware authentication in a new system; and (3) demonstration of key management for sensor data and command authentication.

More Details

Evaluation of infrasound sensors

Kromer, Richard P.

Sandia is evaluating the performance of various infrasound sensors that could be used as part of the International Monitoring Systems (IMS). Specifications for infrasound stations are outlined in CTBT/PC/II/1/Add.2. This document specifies minimum requirements for sensor, digitizer and system. The infrasound sensors evaluation task has the following objectives: provide an overview of the sensors presently in use; evaluate these sensors with respect to the requirements of the IMS.

More Details

Upgrades for truck transportation of SNM in the Russian Federation

Gardner, B.H.; Kornilovich, E.

The goal of this project is the rapid reduction of risk to truck transportation of SNM in Russia. Enhanced protection is being accomplished by cooperation between the US Department of Energy, MINATOM of Russia, the Russian Ministry of Defense, and various Russian Institutes. This program provides an integrated program of specialized trucks that are equipped with hardened overpack (SNM vault) containers, alarm and communications systems, and armored cabs. Armored escort vehicles are also provided to increase the survivability of the guards escorting convoys. Only indigenous Russian equipment, modified and/or manufactured by Designing Bureau for Motor Vehicle Transport Equipment (KBATO), is provided under this program. The US will not provide assistance in the truck transportation arena without a commitment from the Russian facility to provide heavily armed escorts for SNM movement. Each site conducts a detailed transportation needs assessment study that is used as the basis for prioritizing assistance. The Siberian Chemical Combine (Tomsk-7) was the initial site of cooperation. The designs used at Tomsk-7 are serving as the baseline for all future vehicles modified under this program. In FY98, many vehicles systems have been ordered for various institutes. Many additional systems will be ordered in FY99.

More Details

International Physical Protection Advisory Service

Soo Hoo, Mark S.

Since its inception in 1996, the purpose of the International Physical Protection Advisory Service (IPPAS) has been to provide advice and assistance to International Atomic Energy Agency (IAEA) Member States on strengthening and enhancing the effectiveness of their state system of physical protection of nuclear materials and facilities. Since the protection of nuclear materials and facilities is a Member State`s responsibility, participation within the IPPAS program is voluntary. At the request of a Member State, the IAEA forms a multinational IPPAS team consisting of physical protection specialists. These specialists have broad experience in physical protection system design, implementation, and regulatory oversight. The exact make-up of the team depends upon the needs of the requesting state. IPPAS missions to participating states strive to compare the domestic procedures and practices of the state against international physical protection guidelines (IAEA Information Circular 225) and internationally accepted practice. The missions utilize a top to bottom approach and begin by reviewing the legal and regulatory structure and conclude with reviews of the implementation of the state regulations and international guidelines at individual facilities. IPPAS findings are treated as IAEA Safeguards Confidential Information. To date, IPPAS missions have been concluded in Slovenia, Bulgaria, Romania, Hungary, and Poland.

More Details

U.S.-Russia MPC and A upgrades at the Beloyarsk Nuclear Power Plant

Soo Hoo, Mark S.

During the January 1996 meeting of the Gore-Chernomyrdin Commission, the Beloyarsk Nuclear Power Plant (BNPP) was identified as one of the additional sites for cooperative projects on upgrading Materials Protection, Control and Accounting (MPC and A). Since June 1996, Sandia National Laboratories (SNL), Pacific Northwest National Laboratories (PNNL), and Los Alamos National Laboratory (LANL) have worked with BNPP to upgrade MPC and A at the facility. Some unique challenges were encountered because BNPP has an operating BN-600 600-Megawatt breeder reactor. SNL has been responsible for working with BNPP to implement physical protection upgrades to the Central Alarm Station, Fresh Fuel Storage building, Spent Fuel Storage Area, and Vehicle/Personnel Portal. In addition, improved communication equipment for the Ministry of the Interior (MVD) guards and training of personnel were provided. PNNL has been responsible for coordinating Material Control and Accounting (MC and A) upgrades at BNPP. PNNL, in conjunction with LANL, has implemented such MC and A upgrades as a computerized nuclear materials accounting system, training in MC and A elements, nondestructive assay instrumentation for fresh fuel, installation of a fork detector for measuring spent fuel, and installation of an underwater video camera for verification of spent fuel serial numbers.

More Details

Department of Energy Nuclear Material Protection, Control, and Accounting Program at the Mangyshlak Atomic Energy Complex, Aktau, Republic of Kazakhstan

Case, R.; Berry, R.B.; Eras, A.

As part of the Cooperative Threat Reduction Nuclear Material Protection, Control, and Accounting (MPC and A) Program, the US Department of Energy and Mangyshlak Atomic Energy Complex (MAEC), Aktau, Republic of Kazakstan have cooperated to enhance existing MAEC MPC and A features at the BN-350 liquid-metal fast-breeder reactor. This paper describes the methodology of the enhancement activities and provides representative examples of the MPC and A augmentation implemented at the MAEC.

More Details

The potential use of domestic safeguards interior monitors in International Safeguards

Williams, J.D.

An important future element of International Safeguards instrumentation is expected to be the merging of containment/surveillance and nondestructive assay equipment with domestic physical protection equipment into integrated systems, coupled with remote monitoring. Instrumentation would include interior monitoring and assessment and entry/exit monitoring. Of particular importance is the application of interior monitors in spaces of declared inactivity; for example, in nuclear material storage locations that are entered infrequently. The use of modern interior monitors in International Safeguards offers potential for improving effectiveness and efficiency. Within the context of increased cooperation, one can readily envision increased interaction between International Safeguards and Domestic Safeguards, including increased joint use of State System of Accounting and Control data.

More Details

Characterization techniques for surface-micromachined devices

Eaton, W.P.

Using a microengine as the primary test vehicle, the authors have examined several aspects of characterization. Parametric measurements provide fabrication process information. Drive signal optimization is necessary for increased microengine performance. Finally, electrical characterization of resonant frequency and quality factor can be more accurate than visual techniques.

More Details

International Remote Monitoring Project Argentina nuclear power station remote monitoring system

Schneider, Sigfried L.

A remote monitoring system, designed to monitor spent fuel transfers from wet to dry storage, was installed at the Embalse Nuclear Power Station at Embalse, Argentina. The system consists of 6 gamma and one neutron radiation sensors. Five gamma sensors utilize RF transmission to communicate with Echelon nodes connected to a Local Operating Network (LON). One gamma and one neutron sensor are hardwired to the LON network. Each sensor Echelon node is bound to a single Datalogger that stores data until it receives an acquisition command to download to the Data Acquisition Software (DASW) database. The data from the Datalogger are transferred and stored in the Data Acquisition Software database, which resides on the IAEA MOS-MUX server. At a pre-determined interval, data from the DASW database are converted into Excel files and transferred to the IAEA database every 24 hours. At an predetermined interval all data are transferred to the distribution server located at the ARN laboratory at Ezeiza, Argentina. Remote access to data from the distribution server will be made from IAEA headquarters, Vienna, Austria, from ABACC in Rio de Janeiro, Brazil, from the IAEA field office in Buenos Aires, from ARN, and from Sandia National Laboratories, Albuquerque, New Mexico.

More Details

Deriving and applying generally applicable safety principles

Cooper, Arlin C.

The nuclear detonation safety of modern nuclear weapons depends on a coordinated safety theme incorporating three general safety principles: isolation, inoperability, and incompatibility. The success of this approach has encouraged them to study whether these and/or other principles might be useful in other applications. Not surprisingly, no additional first-principles (based on physical laws) have been identified. However, a more widely applicable definition and application of the principle-based approach has been developed, resulting in a selection of strategies that are basically subsets and varied combinations of the more general principles above. However, identification of principles to be relied on is only one step in providing a safe design. As one other important example, coordinating overall architecture and strategy is essential: the authors term this a safety theme.

More Details

Effective passivation of the low resistivity silicon surface by a rapid thermal oxide/PECVD silicon nitride stack and its application to passivated rear and bifacial Si solar cells

Ruby, Douglas S.

A novel stack passivation scheme, in which plasma silicon nitride (SiN) is stacked on top of a rapid thermal SiO{sub 2} (RTO) layer, is developed to attain a surface recombination velocity (S) approaching 10 cm/s at the 1.3 {Omega}-cm p-type (100) silicon surface. Such low S is achieved by the stack even when the RTO and SiN films individually yield considerably poorer surface passivation. Critical to achieving low S by the stack is the use of a short, moderate temperature anneal (in this study 730 C for 30 seconds) after film growth and deposition. This anneal is believed to enhance the release and delivery of atomic hydrogen from the SiN film to the Si-SiO{sub 2} interface, thereby reducing the density of interface traps at the surface. Compatibility with this post-deposition anneal makes the stack passivation scheme attractive for cost-effective solar cell production since a similar anneal is required to fire screen-printed contacts. Application of the stack to passivated rear screen-printed solar cells has resulted in V{sub oc}`s of 641 mV and 633 mV on 0.65 {Omega}-cm and 1.3 {Omega}-cm FZ Si substrates, respectively. These V{sub oc} values are roughly 20 mV higher than for cells with untreated, highly recombinative back surfaces. The stack passivation has also been used to form fully screen-printed bifacial solar cells which exhibit rear-illuminated efficiency as high as 11.6% with a single layer AR coating.

More Details

Contact modeling for robotics applications

Lafarge, Robert A.

At Sandia National Laboratories (SNL), the authors are developing the ability to accurately predict motions for arbitrary numbers of bodies of arbitrary shapes experiencing multiple applied forces and intermittent contacts. In particular, the authors are concerned with the simulation of systems such as part feeders or mobile robots operating in realistic environments. Preliminary investigation of commercial dynamics software packages led them to the conclusion that they could use commercial software to provide everything they needed except for the contact model. They found that ADAMS best fit their needs for a simulation package. To simulate intermittent contacts, they need collision detection software that can efficiently compute the distances between non-convex objects and return the associated witness features. They also require a computationally efficient contact model for rapid simulation of impact, sustained contact under load, and transition to and from contact conditions. This paper provides a technical review of a custom hierarchical distance computation engine developed at Sandia, called the C-Space Toolkit (CSTk). In addition, they describe an efficient contact model using a non-linear damping term developed by SNL and Ohio State. Both the CSTk and the non-linear damper have been incorporated in a simplified two-body testbed code, which is used to investigate how to correctly model the contact using these two utilities. They have incorporated this model into the ADAMS software using the callable function interface. An example that illustrates the capabilities of the 9.02 release of ADAMS with their extensions is provided.

More Details

Airport testing an explosives detection portal

Rhykerd, C.; Linker, K.; Hannum, D.; Bouchier, F.; Parmeter, J.

At the direction of the US Congress, following the Pan Am 103 and TWA 800 crashes, the Federal Aviation Administration funded development of non-invasive techniques to screen airline passengers for explosives. Such an explosives detection portal, developed at Sandia National Laboratories, was field tested at the Albuquerque International airport in September 1997. During the 2-week field trial, 2,400 passengers were screened and 500 surveyed. Throughput, reliability, maintenance and sensitivity were studied. Follow-up testing at Sandia and at Idaho National Engineering and Environmental Laboratory was conducted. A passenger stands in the portal for five seconds while overhead fans blow air over his body. Any explosive vapors or dislodged particles are collected in vents at the feet. Explosives are removed from the air in a preconcentrator and subsequently directed into an ion mobility spectrometer for detection. Throughput measured 300 passengers per hour. The non-invasive portal can detect subfingerprint levels of explosives residue on clothing. A survey of 500 passengers showed a 97% approval rating, with 99% stating that such portals, if effective, should be installed in airports to improve security. Results of the airport test, as well as operational issues, are discussed.

More Details

Security effectiveness review (SER)

Ek, David R.

As part of the on-going DOE/Russian MPC and A activities at the Institute of Physics and Power Engineering (IPPE) and in order to provide a basis for planning MPC and A enhancements, an expedient method to review the effectiveness of the MPC and A system has been adopted. These reviews involve the identification of appropriate and cost-effective enhancements of facilities at IPPE. This effort requires a process that is thorough but far less intensive than a traditional vulnerability assessment. The SER results in a quick assessment of current and needed enhancements. The process requires preparation and coordination between US and Russian analysts before, during, and after information gathering at the facilities in order that the analysis is accurate, effective, and mutually agreeable. The goal of this paper is to discuss the SER process, including the objectives, time scale, and lessons learned at IPPE.

More Details

Cooperation between the Russian Federation and the United States to enhance the existing nuclear-material protection, control, and accounting systems at Mayak Production Association

James, L.T.

The Ministry of the Russian Federation for Atomic Energy (MINATOM) and the US Department of Energy (DOE) are engaged in joint, cooperative efforts to reduce the likelihood of nuclear proliferation by enhancing Material Protection, Control and Accounting (MPC and A) systems in both countries. Mayak Production Association (Mayak) is a major Russian nuclear enterprise within the nuclear complex that is operated by MINATOM. This paper describes the nature, scope, and status of the joint, cooperative efforts to enhance existing MPC and A systems at Mayak. Current cooperative efforts are focused on enhancements to the existing MPC and A systems at two plants that are operated by Mayak and that produce, process, handle and/or store proliferation-sensitive nuclear materials.

More Details

Thermal behavior in the LENS process

Griffith, M.L.

Direct laser metal deposition processing is a promising manufacturing technology which could significantly impact the length of time between initial concept and finished part. For adoption of this technology in the manufacturing environment, further understanding is required to ensure robust components with appropriate properties are routinely fabricated. This requires a complete understanding of the thermal history during part fabrication and control of this behavior. This paper will describe research to understand the thermal behavior for the Laser Engineered Net Shaping (LENS) process, where a component is fabricated by focusing a laser beam onto a substrate to create a molten pool in which powder particles are simultaneously injected to build each layer. The substrate is moved beneath the laser beam to deposit a thin cross section, thereby creating the desired geometry for each layer. After deposition of each layer, the powder delivery nozzle and focusing lens assembly is incremented in the positive Z-direction, thereby building a three dimensional component layer additively. It is important to control the thermal behavior to reproducibly fabricate parts. The ultimate intent is to monitor the thermal signatures and to incorporate sensors and feedback algorithms to control part fabrication. With appropriate control, the geometric properties (accuracy, surface finish, low warpage) as well as the materials` properties (e.g., strength, ductility) of a component can be dialed into the part through the fabrication parameters. Thermal monitoring techniques will be described, and their particular benefits highlighted. Preliminary details in correlating thermal behavior with processing results will be discussed.

More Details

Software development for Laser Engineered Net Shaping

Ensz, M.T.

Laser Engineered Net Shaping, also known as LENS{trademark}, is an advanced manufacturing technique used to fabricate near-net shaped, fully dense metal components directly from computer solid models without the use of traditional machining processes. The LENS{trademark} process uses a high powered laser to create a molten pool into which powdered metal is injected and solidified. Like many SFF techniques, LENS{trademark} parts are made through a layer additive process. In the current system, for any given layer, the laser is held stationary, while the part and its associated substrate is moved, allowing for the each layer`s geometry to be formed. Individual layers are generated by tracing out the desired border, followed by filling in the remaining volume. Recent research into LENS{trademark} has highlighted the sensitivity of the processes to multiple software controllable parameters such as substrate travel velocity, border representation, and fill patterns. This research is aimed at determining optimal border outlines and fill patterns for LENS{trademark} and at developing the associated software necessary for automating the creation of the desired motion control.

More Details

The (safety-related) heat exchangers aging management guideline for commercial nuclear power plants, and developments since 1994

Clauss, John M.

More Details

Manufacturing improvements in the Photovoltaic Manufacturing Technology (PVMaT) Project

Ruby, Douglas S.

The Photovoltaic Manufacturing Technology Project (PVMaT) is a government/industry research and development (R and D) partnership between the US federal government (through the US Department of Energy [DOE]) and members of the US PV industry. The goals of PVMaT are to help the US PV industry improve module manufacturing processes and equipment; accelerate manufacturing cost reductions for PV modules, balance-of-systems components, and integrated systems; increase commercial product performance and reliability; and enhance the investment opportunities for substantial scale-ups of US-based PV manufacturing plant capacities. The approach for PVMaT has been to cost-share risk taking by industry as it explores new manufacturing options and ideas for improved PV modules and other components, advances system and product integration, and develops new system designs, all of which will lead to overall reduced system life-cycle costs for reliable PV end products. The PVMaT Phase 4A module manufacturing R and D projects are just being completed and initial results for the work directed primarily to module manufacture are reported in this paper. Fourteen new Phase 5A subcontracts have also just been awarded and planned R and D areas for the ten focused on module manufacture are described. Finally, government funding, subcontractor cost sharing, and a comparison of the relative efforts by PV technology throughout the PVMaT project are presented.

More Details

Preparation and characterization of phenyl-, benzyl-, and phenethyl-substituted polysilsesquioxanes

American Chemical Society, Polymer Preprints, Division of Polymer Chemistry

Schneider, Duane A.

Polymerization of phenyl-, benzyl-, and phenethyltroalkoxysilanes formed soluble oligo- and polysilsesquixanes. No gels of any of the monomers were observed to form. The molecular weights of the materials prepared and dried at room temperature were near 2K, but would continuously increase with heating at 100°C to between 5-15K. The polymers were structurally characterized by 1H, 13C, and 29Si NMR.

More Details

National Environmental Policy Act (NEPA) compliance at Sandia National Laboratories/New Mexico (SNL/NM)

Wolff, Theodore A.

This report on National Environmental Policy Act (NEPA) compliance at Sandia National Laboratories/New Mexico (SNL/NM) chronicles past and current compliance activities and includes a recommended strategy that can be implemented for continued improvement. This report provides a list of important references. Attachment 1 contains the table of contents for SAND95-1648, National Environmental Policy Act (NEPA) Compliance Guide Sandia National Laboratories (Hansen, 1995). Attachment 2 contains a list of published environmental assessments (EAs) and environmental impact statements (EISs) prepared by SNL/NM. Attachment 3 contains abstracts of NEPA compliance papers authored by SNL/NM and its contractors.

More Details

Damage mechanics characterization on fatigue behavior of a solder joint material

Fang, H.E.

This paper presents the first part of a comprehensive mechanics approach capable of predicting the integrity and reliability of solder joint material under fatigue loading without viscoplastic damage considerations. A separate report will be made to present a comprehensive damage model describing life prediction of the solder material under thermomechanical fatigue loading. The method is based on a theory of damage mechanics which makes possible a macroscopic description of the successive material deterioration caused by the presence of microcracks/voids in engineering materials. A damage mechanics model based on the thermodynamic theory of irreversible processes with internal state variables is proposed and used to provide a unified approach in characterizing the cyclic behavior of a typical solder material. With the introduction of a damage effect tensor, the constitutive equations are derived to enable the formulation of a fatigue damage dissipative potential function and a fatigue damage criterion. The fatigue evolution is subsequently developed based on the hypothesis that the overall damage is induced by the accumulation of fatigue and plastic damage. This damage mechanics approach offers a systematic and versatile means that is effective in modeling the entire process of material failure ranging from damage initiation and propagation leading eventually to macro-crack initiation and growth. As the model takes into account the load history effect and the interaction between plasticity damage and fatigue damage, with the aid of a modified general purpose finite element program, the method can readily be applied to estimate the fatigue life of solder joints under different loading conditions.

More Details

Improved performance of self-aligned, selective-emitter silicon solar cells

Ruby, Douglas S.

The authors improved a self-aligned emitter etchback technique that requires only a single emitter diffusion and no alignment to form self-aligned, patterned-emitter profiles. Standard commercial screen-printed gridlines mask a plasma-etchback of the emitter. A subsequent PECVD-nitride deposition provides good surface and bulk passivation and an antireflection coating. They used full-size multicrystalline silicon (mc-Si) cells processed in a commercial production line and performed a statistically designed multiparameter experiment to optimize the use of a hydrogenation treatment to increase performance. They obtained an improvement of almost a full percentage point in cell efficiency when the self-aligned emitter etchback was combined with an optimized 3-step PECVD-nitride surface passivation and hydrogenation treatment. They also investigated the inclusion of a plasma-etching process that results in a low-reflectance, textured surface on multicrystalline silicon cells. Preliminary results indicate reflectance can be significantly reduced without etching away the emitter diffusion.

More Details

Final report on the development of a 250-kW modular, factory-assembled battery energy storage system

Butler, Paul C.

A power management energy storage system was developed for stationary applications such as peak shaving, voltage regulation, and spinning reserve. Project activities included design, manufacture, factory testing, and field installation. The major features that characterize the development are the modularity of the production, its transportability, the power conversion method that aggregates power on the AC side of the converter, and the use of commonly employed technology for system components. 21 figs.

More Details

Energy storage systems program report for FY97

Butler, Paul C.

Sandia National Laboratories, New Mexico, conducts the Energy Storage Systems Program, which is sponsored by the US Department of Energy`s Office of Utility Technologies. The goal of this program is to collaborate with industry in developing cost-effective electric energy storage systems for many high-value stationary applications. Sandia National Laboratories is responsible for the engineering analyses, contracted development, and testing of energy storage components and systems. This report details the technical achievements realized during fiscal year 1997. 46 figs., 20 tabs.

More Details

Public perspectives on nuclear security. US national security surveys, 1993--1997

Gilliom, Laura R.

This is the third report in a series of studies to examine how US attitudes about nuclear security are evolving in the post-Cold War era and to identify trends in public perceptions and preferences relevant to the evolution of US nuclear security policy. It presents findings from three surveys: a nationwide telephone survey of randomly selected members of the US general public; a written survey of randomly selected members of American Men and Women of Science; and a written survey of randomly selected state legislators from all fifty US states. Key areas of investigation included nuclear security, cooperation between US and Russian scientists about nuclear issues, vulnerabilities of critical US infrastructures and responsibilities for their protection, and broad areas of US national science policy. While international and US national security were seen to be slowly improving, the primary nuclear threat to the US was perceived to have shifted from Russia to China. Support was found for nuclear arms control measures, including mutual reductions in stockpiles. However, respondents were pessimistic about eliminating nuclear armaments, and nuclear deterrence continued to be highly values. Participants favored decreasing funding f/or developing and testing new nuclear weapons, but supported increased investments in nuclear weapons infrastructure. Strong concerns were expressed about nuclear proliferation and the potential for nuclear terrorism. Support was evident for US scientific cooperation with Russia to strengthen security of Russian nuclear assets. Elite and general public perceptions of external and domestic nuclear weapons risks and external and domestic nuclear weapons benefits were statistically significantly related to nuclear weapons policy options and investment preferences. Demographic variables and individual belief systems were systematically related both to risk and benefit perceptions and to policy and spending preferences.

More Details

Building an FTP guard

Sands, P.D.

Classified designs usually include lesser classified (including unclassified) components. An engineer working on such a design needs access to the various sub-designs at lower classification levels. For simplicity, the problem is presented with only two levels: high and low. If the low-classification component designs are stored in the high network, they become inaccessible to persons working on a low network. In order to keep the networks separate, the component designs may be duplicated in all networks, resulting in a synchronization problem. Alternatively, they may be stored in the low network and brought into the high network when needed. The latter solution results in the use of sneaker-net (copying the files from the low system to a tape and carrying the tape to a high system) or a file transfer guard. This paper shows how an FTP Guard was constructed and implemented without degrading the security of the underlying B3 platform. The paper then shows how the guard can be extended to an FTP proxy server or an HTTP proxy server. The extension is accomplished by allowing the high-side user to select among items that already exist on the low-side. No high-side data can be directly compromised by the extension, but a mechanism must be developed to handle the low-bandwidth covert channel that would be introduced by the application.

More Details

Small sample properties of an adaptive filter with application to low volume statistical process control

Crowder, Stephen V.

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

More Details

An open framework for risk management

Craft, R.

Risk assessment methodologies are ready to enter their third generation. In this next generation, assessment will be based on a whole system understanding of the system to be assessed. To realize this vision of risk management, the authors have begun development of an extensible software tool kit. This tool kit breaks with the traditional approach to assessment by having the analyst spend the majority of the assessment time building an explicit model that documents in a single framework the various facets of the system, such as the system`s behavior, structure, and history. Given this explicit model of the system, a computer is able to automatically produce a standard assessment products, such as fault trees and event trees. This brings with it a number of advantages relative to current risk management tools. Among these are a greater sense of completeness and correctness in assessment results and the ability to preserve and later employ lessons learned.

More Details

Polymerization of trialkoxysilanes. Effect of the organic substituent on the formation of gels

American Chemical Society, Polymer Preprints, Division of Polymer Chemistry

Loy, Douglas A.

The sol-gel chemistry of a variety of trialkoxysilanes with different organic substituents, with methoxide or ethoxide substituents on silicon was examined at varying monomer concentrations ranging up to neat monomer and with different catalysts. Gels were prepared from tetramethoxysilane and tetraethoxysilane at identical concentrations for purposes of comparison. The polymerization reactions were monitored for the formation of gels, insoluble precipitates, soluble polymers, or polyhedral oligosilsesquioxanes.

More Details

Modeling the infrastructure dynamics of China -- Water, agriculture, energy, and greenhouse gases

Conrad, Stephen H.

A comprehensive critical infrastructure analysis of the People`s Republic of China was performed to address questions about China`s ability to meet its long-term grain requirements and energy needs and to estimate greenhouse gas emissions in China likely to result from increased agricultural production and energy use. Four dynamic computer simulation models of China`s infrastructures--water, agriculture, energy and greenhouse gas--were developed to simulate, respectively, the hydrologic budgetary processes, grain production and consumption, energy demand, and greenhouse gas emissions in China through 2025. The four models were integrated into a state-of-the-art comprehensive critical infrastructure model for all of China. This integrated model simulates diverse flows of commodities, such as water and greenhouse gas, between the separate models to capture the overall dynamics of the integrated system. The model was used to generate projections of China`s available water resources and expected water use for 10 river drainage regions representing 100% of China`s mean annual runoff and comprising 37 major river basins. These projections were used to develop estimates of the water surpluses and/or deficits in the three end-use sectors--urban, industrial, and agricultural--through the year 2025. Projections of the all-China demand for the three major grains (corn, wheat, and rice), meat, and other (other grains and fruits and vegetables) were also generated. Each geographic region`s share of the all-China grain demand (allocated on the basis of each region`s share of historic grain production) was calculated in order to assess the land and water resources in each region required to meet that demand. Growth in energy use in six historically significant sectors and growth in greenhouse gas loading were projected for all of China.

More Details

Discrete-event simulation for the design and evaluation of physical protection systems

Jordan, S.E.; Snell, M.K.; Madsen, M.M.; Smith, J.S.; Peters, B.A.

This paper explores the use of discrete-event simulation for the design and control of physical protection systems for fixed-site facilities housing items of significant value. It begins by discussing several modeling and simulation activities currently performed in designing and analyzing these protection systems and then discusses capabilities that design/analysis tools should have. The remainder of the article then discusses in detail how some of these new capabilities have been implemented in software to achieve a prototype design and analysis tool. The simulation software technology provides a communications mechanism between a running simulation and one or more external programs. In the prototype security analysis tool, these capabilities are used to facilitate human-in-the-loop interaction and to support a real-time connection to a virtual reality (VR) model of the facility being analyzed. This simulation tool can be used for both training (in real-time mode) and facility analysis and design (in fast mode).

More Details

ISIS; An Information-efficient Spectral Imaging System

Sweatt, W.C.

A specialized hyperspectral imager has been developed that preprocesses the spectra from an image before the light reaches the detectors. This "optical computer" does not allow the flexibility of digital post-processing. However, the processing is done in real time and the system can examine = 2 x 10{sup 6} scene pixels/sec. Therefore, outdoors it could search for pollutants, vegetation types, minerals, or man-made objects. On a high- speed production line it could identify defects in sheet products like plastic wrap or film, or on painted or plastic parts. ISIS is a line scan imager. A spectrally dispersed slit image is projected on a Spatial Light Modulator. The SLM is programmed to take the inner product of the spectral intensity vector and a spectral basis vector. The SLM directs the positive and negative parts of the inner product to different linear detector arrays so the signal difference equals the inner product. We envision a system with one telescope and =4 SLMS.

More Details

Engineered Surety Using the Risk Equation (EnSURE)

Jaeger, Cal

Engineered Surety Using the Risk Equation (EnSURE) is a new approach being developed by Sandia National Laboratories for determining and mitigating risk. The EnSURE approach is based on the risk equation, which can be defined by the following equation: R = (Pa)(1-Pe)(C). Where R is risk, Pa is the likelihood of attack, Pe is the system effectiveness and C is the consequence. EnSURE considers each of the components of risk to help in assessing surety (e.g. security, safety, environmental) and providing for the most cost-effective ways to reduce risk. EnSURE is intended to help in evaluating and reducing the risk from either man-caused or natural events. It will help the decision-makers identify possible targets, evaluate the consequences of an event, assess the risk based on the threat and the existing conditions and then help in the application of mitigating measures. EnSURE is in the development stages. It builds on existing and ongoing development activities at Sandia, as well as the considerable work done in the fields of consequence analysis, risk analysis and intelligence. The components of EnSURE include consequences, constraints, threat, target/goal identification, facility/process characterization, evaluation and analysis, system improvement, and decision making. This paper provides a brief description of EnSURE.

More Details

Security message exchange interoperability scenarios

Tarman, Thomas D.

This contribution describes three interoperability scenarios for the ATM Security Message Exchange (SME) protocol. These scenarios include network-wide signaling support for the Security Services Information Element, partial signaling support wherethe SSIE is only supported in private or workgroup ATM networks, and the case where the SSIE is nonsupported by any network elements (exceptthosethat implement security services). Explanatory text is proposed for inclusion infection 2.3 of the ATM Security Specification, Version 1.0.

More Details

Transient radiation effects in D.O.I. optical materials: KD{sup *}P

Simmons-Potter, K.

Department of Energy and Defense Programs systems are becoming increasingly reliant on the use of optical technologies that must perform under a range of ionizing radiation environments. In particular, the radiation response of materials under consideration for applications in direct optical initiation (D.O.I.) schemes must be well characterized. In this report, transient radiation effects observed in a KD*P crystal are characterized. Under gamma exposure with 2 MeV photons in a 20--30 nsec pulse, the authors observe induced absorption at 1.06 {micro}m that causes a peak decrease in overall sample transmittance of only 10%. This induced loss is seen to recover fully within the first 30 {micro}sec.

More Details

Transient radiation effects in D.O.I. optical materials: Schott filter glass

Simmons-Potter, K.

Department of Energy and Defense Programs systems are becoming increasingly reliant on the use of optical technologies that must perform under a range of ionizing radiation environments. In particular, the radiation response of materials under consideration for applications in direct optical initiation (D.O.I.) schemes must be well characterized. In this report, transient radiation effects observed in Schott filter glass S-7010 are characterized. Under gamma exposure with 2 MeV photons in a 20--30 nsec pulse, the authors observe strong initial induced fluorescence in the red region of the spectrum followed by significant induced absorption over the same spectral region. Peak induced absorption coefficients of 0.113 cm{sup {minus}1} and 0.088 cm{sup {minus}1} were calculated at 800 nm and 660 nm respectively.

More Details

High consequence operations safety symposium 2: Proceedings

D'Antonio, Perry E.

From July 29 to 31, 1997, the Surety Assessment Center at Sandia National Laboratories hosted the second international symposium on High Consequence Operations Safety, HCOSSII. The two and one-half day symposium allowed participants to share strategies, methodologies, and experiences in high consequence engineering and system design. The symposium addressed organizational influences on high consequence safety, assessment and analysis processes, lessons-learned from high consequence events, human factors in safety, and software safety. A special session at the end of the symposium featured a presentation by Federal Nuclear Center--All Russian Research Institute of Experimental Physics and Sandia National Laboratories personnel on their joint efforts to establish the International Surety Center for Energy Intensive and High Consequence Systems and Infrastructures.

More Details

3D EM imaging from a single borehole; a numerical feasibility study

Alumbaugh, D.L.

Often the drilling of an oil well is followed by a logging process to characterize the region immediately surrounding the well bore. The electromagnetic (EM) induction tool, which provides the formation resistivity, is among the most frequently run logs. A preliminary study has been conducted to analyze the feasibility of three dimensional (3D) electromagnetic (EM) imaging from a single borehole. The logging tool consists of a vertical magnetic dipole source and multiple 3 component magnetic field receivers offset at different distances from the source. Synthetic data calculated with a 3D finite difference code demonstrate that the phase of the horizontal magnetic fields provides the critical information on the three dimensionality of the medium. A 3D inversion algorithm is then employed to demonstrate the plausibility of 3D inversion using 3 component magnetic field data. Finally, problems associated with introducing biased noise into the horizontal components of the field through misalignment of the logging tool is discussed.

More Details

Infrasound records from U.S. atmospheric tests

Chael, Eric P.

The United States conducted over 100 atmospheric nuclear tests at the Nevada Test Site from 1951 through 1962. Some of the earliest tests caused unexpected damage, primarily broken glass and cracked plaster, in Las Vegas and other surrounding communities. To address this problem, Sandia initiated a program to monitor and predict the pressure waves around NTS. Infrasound recording systems were developed, then field for all tests beginning with Operation Buster in October 1951. Investigators soon discovered that near-surface temperature inversions and wind profiles caused the damaging pressures in Las Vegas. A typical test was recorded at about a dozen stations from the Control Point on NTS to as far away as Pasadena, CA. In addition, some tests in the South Pacific were monitored, as well as numerous chemical explosions. Strip charts recorded signals in the frequency band from 0.05 to 30 Hz, and the paper tapes were achieved at Sandia in the early 1970s. The NTS events ranged in yield from below 1 ton to 74 kilotons; source altitudes varied from near ground level (including some cratering experiments) to as high as 11 km. The resulting data contain a wealth of information on the source function, yield scaling and regional propagation of infrasound signals from atmospheric explosions. The renewed interest in infrasonic monitoring for CTBT verification has prompted the authors to exhume some of the archived records. The authors plan to digitize the signals from several tests and evaluate their applicability to CTBT issues. In addition, they will collect any existing parametric measurements for these records (arrival times, amplitudes, etc.). All data will be converted to CSS database format and made available to the research community. If appropriate, the resulting information could also be included in the Knowledge Base under development for CTBT monitoring.

More Details

Anomaly detection using simulated MTI data cubes derived from HYDICE data

Moya, Mary M.

The US Department of Energy is funding the development of the Multi-spectral Thermal Imager (MTI), a satellite-based multi-spectral (MS) thermal imaging sensor scheduled for launch in October 1999. MTI is a research and development (R and D) platform to test the applicability of multispectral and thermal imaging technology for detecting and monitoring signs of proliferation of weapons of mass destruction. During its three-year mission, MTI will periodically record images of participating government, industrial and natural sites in fifteen visible and infrared spectral bands to provide a variety of image data associated with weapons production activities. The MTI satellite will have spatial resolution in the visible bands that is five times better than LANDSAT TM in each dimension and will have five thermal bands. In this work, the authors quantify the separability between specific materials and the natural background by applying Receiver Operating Curve (ROC) analysis to the residual errors from a linear unmixing. The authors apply the ROC analysis to quantify performance of the MTI. They describe the MTI imager and simulate its data by filtering HYDICE hyperspectral imagery both spatially and spectrally and by introducing atmospheric effects corresponding to the MTI satellite altitude. They compare and contrast the individual effects on performance of spectral resolution, spatial resolution, atmospheric corrections, and varying atmospheric conditions.

More Details

Backside localization of open and shorted IC interconnections

Cole Jr., E.I.; Tangyunyong, P.; Barton, D.L.

A new failure analysis technique has been developed for backside and frontside localization of open and shorted interconnections on ICs. This scanning optical microscopy technique takes advantage of the interactions between IC defects and localized heating using a focused infrared laser ({lambda} = 1,340 nm). Images are produced by monitoring the voltage changes across a constant current supply used to power the IC as the laser beam is scanned across the sample. The method utilizes the Seebeck Effect to localize open interconnections and Thermally-Induced Voltage Alteration (TIVA) to detects shorts. The interaction physics describing the signal generation process and several examples demonstrating the localization of opens and shorts are described. Operational guidelines and limitations are also discussed.

More Details

Effects of microstructural heterogeneity on BGA reliability

Neilsen, Michael K.

The near eutectic 60Sn-40Pb alloy is the most commonly used solder for electrical interconnections in electronic packages. This alloy has a number of processing advantages (suitable melting point of 183 C and good wetting behavior). However, under conditions of cyclic strain and temperature (thermomechanical fatigue), the microstructure of this alloy undergoes a heterogeneous coarsening and failure process that makes the prediction of solder joint lifetime complex. A viscoplastic constitutive model for solder with an internal state variable that tracks microstructural evolution is currently under development. This constitutive model was implemented in to several finite element codes. With this computational capability, the thermomechanical response of solder interconnects, including microstructural evolution, can be predicted. This capability was applied to predict the thermomechanical response of a ball grid array (BGA) solder interconnect. BGAs with both homogeneous and heterogeneous initial microstructures were evaluated. In this paper, the constitutive model used to describe the solder will first be briefly discussed. The results of computational studies to determine the thermomechanical response of BGA solder interconnects will then be presented.

More Details

Use of radiation detectors in remote monitoring for containment and surveillance

Dupree, S.A.

Radiation detectors have been included in several remote monitoring field trial systems to date. The present study considers detectors at Embalse, Argentina, and Oarai, Japan. At Embalse four gamma detectors have been operating in the instrumentation tubes of spent fuel storage silos for up to three years. Except for minor fluctuations, three of the detectors have operated normally. One of the detectors appears never to have operated correctly. At Oarai two gamma detectors have been monitoring a spent-fuel transfer hatch for over 18 months. These detectors have operated normally throughout the period, although one shows occasional noise spikes.

More Details

MPC and A upgrades at the Institute of Theoretical and Experimental Physics (ITEP)

Baumann, Mark J.

Materials Protection, Control and Accounting (MPC and A) equipment upgrades are complete at the Institute of Theoretical and Experimental Physics (ITEP), a site that has significant quantities of weapons-potential nuclear materials. Cooperative work was initiated at this Moscow facility as a part of the US-Russian program to upgrade MPC and A systems. An initial site visit and assessment were conducted in September 1996 to establish communication between ITEP, the US Department of Energy (DOE), and participating US National Laboratories. Subsequently, an agreement was reached to develop two master plans for MPC and A upgrades. Los Alamos National Laboratory (LANL) and Oak Ridge National Laboratory (ORNL) assisted in developing a plan for Material Control and Accounting (MC and A) upgrades, and Sandia National Laboratories (SNL) assisted in developing a plan for Physical Protection System (PPS) upgrades. The MC and A plan included MC and A training, a mass measurement program, nondestructive assay instrumentation, item identification (bar coding), physical inventory taking, portal and hand-held nuclear material monitors, and a nuclear materials accounting system. The PPS plan included basic PPS design training, Central Alarm Station (CAS) relocation and equipment upgrades, a site and critical-building access control system, intrusion detection, alarm assessment, and guard force communications.

More Details

Security improvements for rail movements of SNM

Garcia, M.R.; Gronager, J.E.; Shemigon, N.N.

The US Department of Energy (DOE) and the Russian Special Scientific and Production State Enterprise Eleron have teamed to lead a project to enhance the overall security of Russian Ministry of Atomic Energy (MINATOM) transportation of Special Nuclear Material (SNM) shipments. The effort is called the Railcar Transportation Security Project and is part of the overall DOE Material Protection, Control, and Accounting (MPC and A) program addressing the enhancement of nuclear material control, accounting, and physical protection for Russian SNM. The goal of this MPC and A project is to significantly increase the security of Russian MINATOM highly enriched SNM rail shipments. To accomplish this, the MPC and A Railcar Transportation Security program will provide an enhanced, yet cost effective, railcar transportation security system. The system incorporates a balance between the traditional detection, communications, delay, and response security elements to significantly improve the security of MINATOM SNM shipments. The strategy of this program is to use rapid upgrades to implement mature security technologies as quickly as possible. The rapid upgrades emphasize rapidly deployable delay elements, enhanced radio communications, and intrusion detection and surveillance. Upgraded railcars have begun operation during FY98. Subsequent upgrades will build upon the rapid upgrades and eventually be integrated into a final deployed system configuration. This paper provides an overview of the program, with a summary of performance of the deployed railcars.

More Details

Stabilization of in-tank residual wastes and external-tank soil contamination for the tank focus area, Hanford tank initiative: Applications to the AX Tank Farm

Balsley, Steven D.

A combined engineering and geochemistry approach is recommended for the stabilization of waste in decommissioned tanks and contaminated soils at the AX Tank Farm, Hanford, WA. A two-part strategy of desiccation and gettering is proposed for treatment of the in-tank residual wastes. Dry portland cement and/or fly ash are suggested as an effective and low-cost desiccant for wicking excess moisture from the upper waste layer. Getters work by either ion exchange or phase precipitation to reduce radionuclide concentrations in solution. The authors recommend the use of specific natural and man-made compounds, appropriately proportioned to the unique inventory of each tank. A filler design consisting of multilayered cementitous grout with interlayered sealant horizons should serve to maintain tank integrity and minimize fluid transport to the residual waste form. External tank soil contamination is best mitigated by placement of grouted skirts under and around each tank, together with installation of a cone-shaped permeable reactive barrier beneath the entire tank farm. Actinide release rates are calculated from four tank closure scenarios ranging from no action to a comprehensive stabilization treatment plan (desiccant/getters/grouting/RCRA cap). Although preliminary, these calculations indicate significant reductions in the potential for actinide transport as compared to the no-treatment option.

More Details

Exponential 6 parameterization for the JCZ3-EOS

Hobbs, Michael L.

A database has been created for use with the Jacobs-Cowperthwaite-Zwisler-3 equation-of-state (JCZ3-EOS) to determine thermochemical equilibrium for detonation and expansion states of energetic materials. The JCZ3-EOS uses the exponential 6 intermolecular potential function to describe interactions between molecules. All product species are characterized by r*, the radius of the minimum pair potential energy, and {var_epsilon}/k, the well depth energy normalized by Boltzmann`s constant. These parameters constitute the JCZS (S for Sandia) EOS database describing 750 gases (including all the gases in the JANNAF tables), and have been obtained by using Lennard-Jones potential parameters, a corresponding states theory, pure liquid shock Hugoniot data, and fit values using an empirical EOS. This database can be used with the CHEETAH 1.40 or CHEETAH 2.0 interface to the TIGER computer program that predicts the equilibrium state of gas- and condensed-phase product species. The large JCZS-EOS database permits intermolecular potential based equilibrium calculations of energetic materials with complex elemental composition.

More Details

The Atom-Probe Field Ion Microscope: Applications in Surface M Science

Microscopy and Microanalysis

Kellogg, Gary L.

The ability to locate an individual atom on a surface, remove it in a controlled fashion, and determine its chemical identity makes the atom-probe field-ion microscope an extremely powerful tool for the analysis of solid surfaces. By itself, the field ion microscope has contributed significantly to our understanding of surface atomic structure, single-atom surface diffusion, and the detailed interactions that occur between atoms and defects on surfaces.1 When used in combination with the atom-probe mass spectrometer there have been several additional areas within the traditional definition of "surface science"where the chemical identification capability of the atom probe has led to new insights. In this paper these applications are reviewed focusing on two specific areas: surface segregation in intermetallic alloys and chemical reactions on metal surfaces. The equilibrium distribution of component species in the near surface region of solid solution alloy may be different from the distribution in the bulk.

More Details

Statistical cloud coverage as a function of cloud optical thickness

Brower, K.L.

The time-averaged, daylight fractional statistical cloud coverages as a function of cloud optical thickness and selected values of cloud transmission were determined for various geographic areas using D1 data from the International Satellite Cloud Climatology Project (ISCCP). The regions of interest chosen for this report are: global earth, global sea, global land, global coast, and the six 30{degree}-latitude bands over sea, over land, and over coast with longitude 0{degree}--360{degree}. This statistical information is deduced from data determined from satellite measurements of terrestrial, atmospheric and cloud properties by the International Satellite Cloud Climatology Project. In particular the results are based on the ISCCP D1 data base.

More Details

The 1996 performance assessment for the Waste Isolation Pilot Plant

Anderson, D.R.

The Waste Isolation Pilot Plant (WIPP) is under development by the US Department of Energy (DOE) for the geologic disposal of transuranic (TRU) waste that has been generated at government defense installations in the United States. The WIPP is located in an area of low population density in southeastern New Mexico. Waste disposal will take place in excavated chambers in a bedded salt formation approximately 655 m below the land surface. This presentation describes a performance assessment (PA) carried out at Sandia National Laboratories (SNL) to support the Compliance Certification Application (CCA) made by the DOE to the US Environmental Protection Agency (EPA) in October, 1996, for the certification of the WIPP for the disposal of TRU waste. Based on the CCA supported by the PA described in this presentation, the EPA has issued a preliminary decision to certify the WIPP for the disposal of TRU waste. At present (April 1998), it appears likely that the WIPP will be in operation by the end of 1998.

More Details

Uncertainty analysis in the 1996 performance assessment for the Waste Isolation Pilot Plant

Anderson, D.R.

The appropriate treatment of uncertainty is now widely recognized as an essential component of performance assessments (PAs) for complex systems. When viewed at a high-level, the uncertainty in such analyses can typically be partitioned into two types: (1) stochastic uncertainty, which arises because the system can behave in many different ways and is thus a property of the system itself, and (2) subjective uncertainty, which arises from a lack of knowledge about quantities that are believed to have (or, at least, are assumed to have) fixed values and is thus a property of the analysts carrying out the study. The 1996 PA for the Waste Isolation Pilot Plant (WIPP) carried out at Sandia National Laboratories (SNL) will be used to illustrate the treatment of these two types of uncertainty in a real analysis. In particular, this PA supported a compliance certification application (CCA) by the US Department of Energy (DOE) to the US Environmental Protection Agency (EPA) for the certification of the WIPP for the geologic disposal of transuranic waste. Insights on the conceptual and computational structure of PAs for complex systems gained from these and other analyses are being incorporated into a new software system under development at SNL to facilitate the performance of analyses that maintain a separation between stochastic and subjective uncertainty.

More Details

A simple tool to assess the cost-effectiveness of new bit technology

Bomber, Thomas M.

Cost or performance targets for new bit technologies can be established with the aid of a drilling cost model. In this paper the authors make simplifying assumptions in a detailed drilling cost model that reduce the comparison of two technologies to a linear function of relative cost and performance parameters. This simple model, or analysis tool, is not intended to provide absolute well cost but is intended to compare the relative costs of different methods or technologies to accomplish the same drilling task. Comparing the simplified model to the detailed well cost model shows that the simple linear cost model provides a very efficient tool for screening certain new drilling methods, techniques, and technologies based on economic value. This tool can be used to divide the space defined by the set of parameters: bit cost, bit life, rate of penetration, and operational cost into two areas with a linear boundary. The set of all the operating points in one area will result in an economic advantage in drilling the well with the new technology, while any set of operating points in the other area indicates that any economic advantage is either questionable or does not exist. In addition, examining the model results can develop insights into the economics associated with bit performance, life, and cost. This paper includes development of the model, examples of employing the model to develop should cost or should perform goals for new bit technologies, a discussion of the economic insights in terms of bit cost and performance, and an illustration of the consequences when the basic assumptions are violated.

More Details

Tech Area II: A history

Ullrich, Rebecca A.

This report documents the history of the major buildings in Sandia National Laboratories` Technical Area II. It was prepared in support of the Department of Energy`s compliance with Section 106 of the National Historic Preservation Act. Technical Area II was designed and constructed in 1948 specifically for the final assembly of the non-nuclear components of nuclear weapons, and was the primary site conducting such assembly until 1952. Both the architecture and location of the oldest buildings in the area reflect their original purpose. Assembly activities continued in Area II from 1952 to 1957, but the major responsibility for this work shifted to other sites in the Atomic Energy Commission`s integrated contractor complex. Gradually, additional buildings were constructed and the original buildings were modified. After 1960, the Area`s primary purpose was the research and testing of high-explosive components for nuclear weapons. In 1994, Sandia constructed new facilities for work on high-explosive components outside of the original Area II diamond-shaped parcel. Most of the buildings in the area are vacant and Sandia has no plans to use them. They are proposed for decontamination and demolition as funding becomes available.

More Details

Plasmas in quasi-static external electric fields

Riley, Merle E.

This work develops some practical approximations needed to simulate a high plasma density volume bounded by walls made of dielectrics or metals which may be either biased or floating in potential. Solving Poisson`s equation in both the high-density bulk and the sheath region poses a difficult computational problem due to the large electron plasma frequency. A common approximation is to assume the electric field is computed in the ambipolar approximation in the bulk and to couple this to a sheath model at the boundaries. Unfortunately, this treatment is not appropriate when some surfaces are biased with respect to others and a net current is present within the plasma. This report develops some ideas on the application of quasi-static external electric fields to plasmas and the self-consistent treatment of boundary conditions at the surfaces. These constitute a generalization of Ohm`s law for a plasma body that entails solving for the internal fields within the plasma and the potential drop and currents through the sheaths surrounding the plasma.

More Details

Progress in photovoltaic system and component improvements

Bower, Ward I.

The Photovoltaic Manufacturing Technology (PVMaT) project is a partnership between the US government (through the US Department of Energy [DOE]) and the PV industry. Part of its purpose is to conduct manufacturing technology research and development to address the issues and opportunities identified by industry to advance photovoltaic (PV) systems and components. The project was initiated in 1990 and has been conducted in several phases to support the evolution of PV industrial manufacturing technology. Early phases of the project stressed PV module manufacturing. Starting with Phase 4A and continuing in Phase 5A, the goals were broadened to include improvement of component efficiency, energy storage and manufacturing and system or component integration to bring together all elements for a PV product. This paper summarizes PV manufacturers` accomplishments in components, system integration, and alternative manufacturing methods. Their approaches have resulted in improved hardware and PV system performance, better system compatibility, and new system capabilities. Results include new products such as Underwriters Laboratories (UL)-listed AC PV modules, modular inverters, and advanced inverter designs that use readily available and standard components. Work planned in Phase 5A1 includes integrated residential and commercial roof-top systems, PV systems with energy storage, and 300-Wac to 4-kWac inverters.

More Details

Economics and performance of PV hybrid power systems: Three case studies

Thomas, Michael G.

The Photovoltaic Systems Assistance Center (PVSAC) of Sandia National Laboratories (SNL) has been supporting the development and implementation of off-grid PV hybrid power systems for many years. Technical support has included: refining hardware; understanding system design techniques; obtaining operation and maintenance data; studying use of energy produced. As part of the program, the PVSAC has provided technical expertise on hybrid systems to many federal agencies including the National Park Service, the Forest Service, the Bureau of Land Management, and the Department of Defense. The goal of these partnerships has been to ensure that reliable and safe PV hybrid systems are specified and procured. At present, a critical review of performance and costs of several representative PV hybrid systems is underway. This paper presents a summary of the performance and economical analyses conducted on three PV hybrid systems.

More Details

Trimode optimizes hybrid power plants. Final report: Phase 2

Bower, Ward I.

In the Phase 2 project, Abacus Controls Inc. did research and development of hybrid systems that combine the energy sources from photovoltaics, batteries, and diesel-generators and demonstrated that they are economically feasible for small power plants in many parts of the world. The Trimode Power Processor reduces the fuel consumption of the diesel-generator to its minimum by presenting itself as the perfect electrical load to the generator. A 30-kW three-phase unit was tested at Sandia National Laboratories to prove its worthiness in actual field conditions. The use of photovoltaics at remote locations where reliability of supply requires a diesel-generator will lower costs to operate by reducing the run time of the diesel generator. The numerous benefits include longer times between maintenance for the diesel engine and better power quality from the generator. 32 figs.

More Details

Development and evaluation of sealing technologies for photovoltaic panels

Glass, Sarah J.

This report summarizes the results of a study to develop and evaluate low temperature glass sealing technologies for photovoltaic applications. This work was done as part of Cooperative Research and Development Agreement (CRADA) No. SC95/01408. The sealing technologies evaluated included low melting temperature glass frits and solders. Because the glass frit joining required a material with a melting temperature that exceeded the allowable temperature for the active elements on the photovoltaic panels a localized heating scheme was required for sealing the perimeter of the glass panels. Thermal and stress modeling were conducted to identify the feasibility of this approach and to test strategies designed to minimize heating of the glass panel away from its perimeter. Hardware to locally heat the glass panels during glass frit joining was designed, fabricated, and successfully tested. The same hardware could be used to seal the glass panels using the low temperature solders. Solder adhesion to the glass required metal coating of the glass. The adhesion strength of the solder was dependent on the surface finish of the glass. Strategies for improving the polyisobutylene (PIB) adhesive currently being used to seal the panels and the use of Parylene coatings as a protective sealant deposited on the photovoltaic elements were also investigated. Starting points for further work are included.

More Details

Partial discharge in a high voltage experimental test assembly

Koss, R.J.

This study was initiated when a new type of breakdown occurred in a high voltage experimental test assembly. An anomalous current pulse was observed, which indicated partial discharges, some leading to total breakdowns. High voltage insulator defects are shown along with their effect on the electrostatic fields in the breakdown region. OPERA electromagnetic field modeling software is used to calculate the fields and present a cause for the discharge. Several design modifications are investigated and one of the simplest resulted in a 25% decrease in the field at the discharge surface.

More Details

Calculating solvation forces and adsorption in complex geometries with a finite element-nonlocal density functional theory method

Douglas Frink, L.J.; Salinger, A.G.

Density functional theories (DFT) for inhomogeneous fluids have been used profitably to study the structure of fluids near surfaces, and to predict solvation forces, adsorption isotherm, and a variety of surface induced phase transitions. However, in nearly all cases, only geometries with 2 symmetry planes (e.g. fluid near a uniform planar interface or a fluid in a uniform cylindrical pore) have been considered. In this paper the authors discuss the generalization of the DFT to cases with either one or no symmetry planes. They present their computational approach, as well as results for charged cylindrical polyelectrolytes and planar surfaces with inhomogeneous chemistry.

More Details

Gradient-driven diffusion using dual control volume grand canonical molecular dynamics

Heffelfinger, Grant S.

The dual control volume grand canonical molecular dynamics (DCV-GCMD) method, designed to enable the dynamic simulation of a system with a steady state chemical potential gradient is first briefly reviewed. A new, novel implementation of the method which enables the establishment of a steady state chemical potential gradient in a multicomponent system without having to insert or delete one of the components is then presented and discussed.

More Details

Geothermal high temperature instrumentation applications

Normann, Randy A.

A quick look at the geothermal industry shows a small industry producing about $1 billion in electric sales annually. The industry is becoming older and in need of new innovative solutions to instrumentation problems. A quick look at problem areas is given along with basic instrumentation requirements. The focus of instrumentation is on high temperature electronics.

More Details

An integrated model of the lithium/thionyl chloride battery

Jungst, Rudolph G.

The desire to reduce the time and cost of design engineering on new components or to validate existing designs in new applications is stimulating the development of modeling and simulation tools. The authors are applying a model-based design approach to low and moderate rate versions of the Li/SOCl{sub 2} D-size cell with success. Three types of models are being constructed and integrated to achieve maximum capability and flexibility in the final simulation tool. A phenomenology based electrochemical model links performance and the cell design, chemical processes, and material properties. An artificial neural network model improves computational efficiency and fills gaps in the simulation capability when fundamental cell parameters are too difficult to measure or the forms of the physical relationships are not understood. Finally, a PSpice-based model provides a simple way to test the cell under realistic electrical circuit conditions. Integration of these three parts allows a complete link to be made between fundamental battery design characteristics and the performance of the rest of the electrical subsystem.

More Details

Energy and power characteristics of Li-ion cells

Nagasubramanian, Ganesan N.

At Sandia National Laboratories the authors are evaluating the energy and power characteristics of commercially available Li-ion cells. Cells of several different sizes (20 Ah, 1.1 Ah, 0.750 Ah and {approximately}0.5 Ah) and geometries (cylindrical and prismatic) from several manufacturers were studied. The cells were pulsed discharged at increasing currents (50 mA to 1,000 mA) over a range of temperatures (+35 C to {minus}40 C) and at different states of charge (4.1 V, open circuit voltage (OCV), fully charged, 3.6 V OCV partially discharged and 3.1 V OCV nearly discharged) and the voltage drop was recorded. The voltage drop was small at ambient and near ambient temperatures indicating that the total cell internal impedance was small under these conditions. However, at {minus} 40 C the voltage drop was significant due to an increase in the cell internal impedance. At a given temperature, the voltage drop increases with decreasing state-of-charge (SOC) or OCV. The cell impedance and other electrochemical properties as a function of temperature and SOC were also measured. The Ragone data indicate that the specific power and specific energy of Li-ion cells of different sizes are comparable and therefore scaling up to {approximately}20 Ah does not affect either the energy or the power.

More Details

Criticality Safety Study of Unirradiated Cintichem Target Storage

Romero, Daniel J.; Parma, Edward J.; Busch, Robert D.

Sandia National Laboratories has been chosen by the US Department of Energy as the primary domestic source for the production of molybdenum-99, utilizing the Annular Core Research Reactor. The method to be used to produce 99Mo through the fission of 235U in 93% enriched UO2 is based on the process formerly used by Cintichem, Inc. of Tuxedo, New York. The UO2 is electroplated in a thin coating to the inside of stainless steel Cintichem targets which will be irradiated in the central region of the reactor core. The proposed on-site storage plan for the unirradiated targets is to store them in a dry, secure compartment similar to a file cabinet. Each cabinet drawer will be initially filled with targets and emptied as targets are removed for irradiation. The main objective of this analysis was to postulate and model a set of incredible accident scenarios beyond the proposed storage plan which would possibly induce criticality with the targets in the safe, and determine the k-effective and its associated standard deviation for these conditions. A parametric analysis was performed using Los Alamos National Laboratory`s MCNP (Monte Carlo Neutral Particle) code, Version 4A.

More Details

PRONTO3D users` instructions: A transient dynamic code for nonlinear structural analysis

Attaway, Stephen W.; Brown, Kevin H.; Mello, F.J.; Heinstein, Martin W.; Swegle, Jeffrey W.

This report provides an updated set of users` instructions for PRONTO3D. PRONTO3D is a three-dimensional, transient, solid dynamics code for analyzing large deformations of highly nonlinear materials subjected to extremely high strain rates. This Lagrangian finite element program uses an explicit time integration operator to integrate the equations of motion. Eight-node, uniform strain, hexahedral elements and four-node, quadrilateral, uniform strain shells are used in the finite element formulation. An adaptive time step control algorithm is used to improve stability and performance in plasticity problems. Hourglass distortions can be eliminated without disturbing the finite element solution using either the Flanagan-Belytschko hourglass control scheme or an assumed strain hourglass control scheme. All constitutive models in PRONTO3D are cast in an unrotated configuration defined using the rotation determined from the polar decomposition of the deformation gradient. A robust contact algorithm allows for the impact and interaction of deforming contact surfaces of quite general geometry. The Smooth Particle Hydrodynamics method has been embedded into PRONTO3D using the contact algorithm to couple it with the finite element method.

More Details

An Effective Waste Management Process for Segregation and Disposal of Legacy Mixed Waste at Sandia National Laboratories/New Mexico

Hallman, Anne K.

Sandia National Laboratories/New Mexico (SNL/NM) is a research and development facility that generates many highly diverse, low-volume mixed waste streams. Under the Federal Facility Compliance Act, SNL/NM must treat its mixed waste in storage to meet the Land Disposal Restrictions treatment standards. Since 1989, approximately 70 cubic meters (2500 cubic feet) of heterogeneous, poorly characterized and inventoried mixed waste was placed in storage that could not be treated as specified in the SNL/NM Site Treatment Plan. A process was created to sort the legacy waste into sixteen well- defined, properly characterized, and precisely inventoried mixed waste streams (Treatability Groups) and two low-level waste streams ready for treatment or disposal. From June 1995 through September 1996, the entire volume of this stored mixed waste was sorted and inventoried through this process. This process was planned to meet the technical requirements of the sorting operation and to identify and address the hazards this operation presented. The operations were routinely adapted to safely and efficiently handle a variety of waste matrices, hazards, and radiological conditions. This flexibility was accomplished through administrative and physical controls integrated into the sorting operations. Many Department of Energy facilities are currently facing the prospect of sorting, characterizing, and treating a large inventory of mixed waste. The process described in this paper is a proven method for preparing a diverse, heterogeneous mixed waste volume into segregated, characterized, inventoried, and documented waste streams ready for treatment or disposal.

More Details

AT-400A compliance test report

Glass, R.E.

In 1993 Sandia was directed to design containers for the long-term storage and transport of nuclear weapons origin fissile material. This program was undertaken at the direction of the US Department of Energy and in cooperation with Lawrence Livermore National Laboratory and Los Alamos National Laboratory. Lawrence Livermore National Laboratory and Los Alamos National Laboratory were tasked with developing the internal fixturing for the contents. The hardware is being supplied by AlliedSignal Federal Manufacturing and Technologies, and the packaging process has been developed at Mason and Hanger Corporation`s Pantex Plant. The unique challenge was to design a container that could be sealed with the fissile material contents; and, anytime during the next 50 years, the container could be transported with only the need for the pre-shipment leak test. This required a rigorous design capable of meeting the long-term storage and transportation requirements. This report addresses the final testing that was undertaken to demonstrate compliance with US radioactive materials transport regulations.

More Details

Surface-micromachined 1MHz oscillator with low-noise Pierce configuration

Roessig, T.A.; Howe, R.T.; Pisano, A.P.; Smith, J.H.

A prototype high frequency tuning fork oscillator has been fabricated and tested in an integrated surface micromachining technology. The amplifier circuitry uses a capacitive current detection method, which offers superior noise performance over previous resistive methods. The prototype device has an output frequency of 1.022 MHz and exhibits a noise floor of {minus}88 dBc/Hz at a distance of 500 Hz from the carrier. The dominant source of frequency instability is the nonlinearity introduced by the use of parallel plate actuation.

More Details

Investigating a reliable covariance control scheme for MDOF systems

Field Jr., R.V.; Bergman, L.A.

The authors attempt to extend their previous efforts towards a reliable control scheme that guarantees a specified degree of reliability for civil engineering structures. Herein, a two degree of freedom system is examined. Covariance control techniques are explored to design a compensator that will provide optimal closed loop performance, while satisfying a constraint on system reliability. It was found for the system under examination that a stable control does not exist that also meets the target reliability level. Alternate formulations continue to be investigated.

More Details

Testing of an actively damped boring bar featuring structurally integrated PZT stack actuators

Redmond, James M.

This paper summarizes the results of cutting tests performed using an actively damped boring bar to minimize chatter in metal cutting. A commercially available 2 inch diameter boring bar was modified to incorporate PZT stack actuators for controlling tool bending vibrations encountered during metal removal. The extensional motion of the actuators induce bending moments in the host structure through a two-point preloaded mounting scheme. Cutting tests performed at various speeds and depths of cuts on a hardened steel workpiece illustrate the bar`s effectiveness toward eliminating chatter vibrations and improving workpiece surface finish.

More Details

Physico-chemical stability of solid surfaces: Final report

Michalske, Terry A.

The application of physico-chemical phenomena to either increase machinability of hard materials, improve the wear resistance of cutting surfaces, or enhance sintering of particle compacts can have large economic impact on technologies ranging from materials forming processes to oil well drilling. Unfortunately, the broad application of these physico-chemical principles is limited by the authors ability to predict the optimum conditions for a wide variety of materials surfaces. Predictive models must be built upon understanding of the elementary events involved in surface damage and mobility. The authors have developed a new approach to examine the fundamental mechanisms controlling physico-chemical surface stability that combines: (1) atomic-scale control of surface contact forces and displacements under well controlled adsorbate conditions using the Interfacial Force Microscope, (2) atomic-level imaging of surface and near-surface structure and defects using Field Ion Microscopy, and (3) first-principles modeling of the effect of surface stress on adsorbate bonding interactions and the subsequent generation of surface damage. This unique combination of approaches has provided new insights into observed physico-chemical phenomena and provided the basis for developing true predictive models that are needed for wide application of these important new approaches to modifying the surface sensitive properties of materials.

More Details

Post-test comparison of thermal-hydrologic measurements and numerical predictions for the in situ single heater test, Yucca Mountain, Nevada

Ballard, Sanford B.

The Single Heater Test (SHT) is a sixteen-month-long heating and cooling experiment begun in August, 1996, located underground within the unsaturated zone near the potential geologic repository at Yucca Mountain, Nevada. During the 9 month heating phase of the test, roughly 15 m{sup 3} of rock were raised to temperatures exceeding 100 C. In this paper, temperatures measured in sealed boreholes surrounding the heater are compared to temperatures predicted by 3D thermal-hydrologic calculations performed with a finite difference code. Three separate model runs using different values of bulk rock permeability (4 microdarcy to 5.2 darcy) yielded significantly different predicted temperatures and temperature distributions. All the models differ from the data, suggesting that to accurately model the thermal-hydrologic behavior of the SHT, the Equivalent Continuum Model (ECM), the conceptual basis for dealing with the fractured porous medium in the numerical predictions, should be discarded in favor of more sophisticated approaches.

More Details

Gas releases from salt

Ehgartner, Brian L.

The occurrence of gas in salt mines and caverns has presented some serious problems to facility operators. Salt mines have long experienced sudden, usually unexpected expulsions of gas and salt from a production face, commonly known as outbursts. Outbursts can release over one million cubic feet of methane and fractured salt, and are responsible for the lives of numerous miners and explosions. Equipment, production time, and even entire mines have been lost due to outbursts. An outburst creates a cornucopian shaped hole that can reach heights of several hundred feet. The potential occurrence of outbursts must be factored into mine design and mining methods. In caverns, the occurrence of outbursts and steady infiltration of gas into stored product can effect the quality of the product, particularly over the long-term, and in some cases renders the product unusable as is or difficult to transport. Gas has also been known to collect in the roof traps of caverns resulting in safety and operational concerns. The intent of this paper is to summarize the existing knowledge on gas releases from salt. The compiled information can provide a better understanding of the phenomena and gain insight into the causative mechanisms that, once established, can help mitigate the variety of problems associated with gas releases from salt. Outbursts, as documented in mines, are discussed first. This is followed by a discussion of the relatively slow gas infiltration into stored crude oil, as observed and modeled in the caverns of the US Strategic Petroleum Reserve. A model that predicts outburst pressure kicks in caverns is also discussed.

More Details

Estimation of constitutive parameters for the Belridge Diatomite, South Belridge Diatomite Field

Fredrich, Joanne T.

A cooperative national laboratory/industry research program was initiated in 1994 that improved understanding of the geomechanical processes causing well casing damage during oil production from weak, compactible formations. The program focused on the shallow diatomaceous oil reservoirs located in California`s San Joaquin Valley, and combined analyses of historical field data, experimental determination of rock mechanical behavior, and geomechanical simulation of the reservoir and overburden response to production and injection. Sandia National Laboratories` quasi-static, large-deformation structural mechanics finite element code JAS3D was used to perform the three-dimensional geomechanical simulations. One of the material models implemented in JAS3D to simulate the time-independent inelastic (non-linear) deformation of geomaterials is a generalized version of the Sandler and Rubin cap plasticity model (Sandler and Rubin, 1979). This report documents the experimental rock mechanics data and material cap plasticity models that were derived to describe the Belridge Diatomite reservoir rock at the South Belridge Diatomite Field, Section 33.

More Details

Guidebook for performance assessment parameters used in the Waste Isolation Pilot Plant compliance certification application. Volume 1: Main report

Kelly, Susan

The Waste Isolation Pilot Plant (WIPP) Compliance Certification Application (CCA) Performance Assessment (PA) Parameter Database and its ties to supporting information evolved over the course of two years. When the CCA was submitted to the Environmental Protection Agency (EPA) in October 1996, information such as identification of parameter value or distribution source was documented using processes established by Sandia National Laboratories WIPP Quality Assurance Procedures. Reviewers later requested additional supporting documentation, links to supporting information, and/or clarification for many parameters. This guidebook is designed to document a pathway through the complex parameter process and help delineate flow paths to supporting information for all WIPP CCA parameters. In addition, this report is an aid for understanding how model parameters used in the WIPP CCA were developed and qualified. To trace the source information for a particular parameter, a dual-route system was established. The first route uses information from the Parameter Records Package as it existed when the CCA calculations were run. The second route leads from the EPA Parameter Database to additional supporting information.

More Details

Cylindrical target Li-beam-driven hohlraum experiments

Derzon, Mark S.

The authors performed a series of experiments on the Particle Beam Fusion Accelerator II (PBFA II) in May, 1994, and obtained a brightness temperature of 61 {+-} 2 eV for an ion-beam heated hohlraum. The hohlraum was a 4-mm-diameter, right-circular cylinder with a 1.5-mm-thick gold wall, a low-density CH foam fill, and a 1.5- or 3-mm-diameter diagnostic aperture in the top. The nominal parameters of the radially-incident PBFA II Li ion beam were 9 MeV peak energy ({approximately}10 MeV at the gas cell) at the target at a peak power of 2.5 {+-} 0.3 TW/cm{sup 2} and a 15 ns pulse width. Azimuthal variations in intensity of a factor of 3, with respect to the mean, were observed. Nonuniformities in thermal x-ray emission across the area of the diagnostic hole were also observed. Time-dependent hole-closure velocities were measured: the time-averaged velocity of {approximately}2 cm/{micro}s is in good agreement with sound speed estimates. Unfolded x-ray spectra and brightness temperatures as a function of time are reported and compared to simulations. Hole closure corrections are discussed with comparisons between XRD and bolometer measurements. Temperature scaling with power on target is also presented.

More Details

Understanding and control of optical performance from ceramic materials

Barbour, J.C.

This report summarizes a two-year Laboratory-Directed Research and Development (LDRD) program to gain understanding and control of the important parameters which govern the optical performance of rare-earth (RE) doped ceramics. This LDRD developed the capability to determine stable atomic arrangements in RE doped alumina using local density functional theory, and to model the luminescence from RE-doped alumina using molecular dynamic simulations combined with crystal-field calculations. Local structural features for different phases of alumina were examined experimentally by comparing their photoluminescence spectra and the atomic arrangement of the amorphous phase was determined to be similar to that of the gamma phase. The luminescence lifetimes were correlated to these differences in the local structure. The design of both high and low-phonon energy host materials was demonstrated through the growth of Er-doped aluminum oxide and lanthanum oxide. Multicomponent structures of rare-earth doped telluride glass in an alumina and silica matrix were also prepared. Finally, the optical performance of Er-doped alumina was determined as a function of hydrogen content in the host matrix. This LDRD is the groundwork for future experimentation to understand the effects of ionizing radiation on the optical properties of RE-doped ceramic materials used in space and other radiation environments.

More Details

An evaluation of technical review of federal laboratory research: Findings from a US Department of Energy technical review pilot

Kuswa, Glenn W.

Recommendations for improving the process for expert panel reviews of technical and programmatic aspects of science and technology programs are provided based on an evaluation study of pilot reviews for two programs at Sandia National Laboratories. These reviews were part of a larger Technical Review Pilot for the US Department of Energy (DOE). Both the Sandia Pulse Power program and Solar Thermal Electric program (a virtual lab with NREL) reviews used the recommended four DOE review criteria, but motivation for the review and the review process differed. These differences provide insight into recommendations for ways to improve the review of DOE`s multifaceted technical programs. Recommendations are: (1) Review when the program has specific need for information or validation. There is no one size fits all correct time or reason to review technical programs. (2) Tailor the four DOE criteria to the program and its need for information and explain them to the Review Panel. (3) Pay attention to the review process. Spend more time in preparation and pre-review and on briefings on the review outcomes. (4) Evaluate reviews to determine how to do them better. The survey instrument is provided for those who wish to modify it for their own use.

More Details

Just what exactly is a warhead? An analysis of Russian/English translations and definitions

Hadley, A.

That there are significant definitional differences between languages is a statement of the obvious. It logically follows that definitional ambiguity occurs when translating a term from one language to another. The far-reaching implications of this fact, however, are not as widely recognized. One word that has been and will continue to be significant is warhead. This analysis (1) examines the different translations and definitions of the word warhead in English and Russian; (2) discusses the usage of warhead in the context of arms control; and (3) explores the implications definitional differences have for future negotiations. It specifically utilizes treaty texts, as well as the Helsinki agreement text, to construct a contextual use of warhead. It is concluded that if US policymakers are committed to including nuclear explosive devices in START III force reductions, negotiators must identify and use a more specific term than warhead or boyegolovka. Also included as an appendix are copies of the signed Helsinki agreement in both English and Russian.

More Details

Importance of energy efficiency in the design of the Process and Environmental Technology Laboratory (PETL) at Sandia National Laboratories, New Mexico (NM)

Wrons, Ralph J.

As part of the design of the Process and Environmental Technology Laboratory (PETL) in FY97, an energy conservation report (ECR) was completed. The original energy baseline for the building, established in Title 1 design, was 595,000 BTU/sq. ft./yr, site energy use. Following the input of several reviewers and the incorporation of the various recommendations into the Title 2 design, the projected energy consumption was reduced to 341,000 BTU/sq. ft./yr. Of this reduction, it is estimated that about 150,000 BTU/sq. ft./yr resulted from inclusion of more energy efficient options into the design. The remaining reductions resulted from better accounting of energy consumption between Title 1 ECR and the final ECR. The energy efficient features selected by the outcome of the ECR were: (1) Energy Recovery system, with evaporative cooling assist, for the Exhaust/Make-up Air System; (2) Chilled Water Thermal Storage system; (3) Premium efficiency motors for large, year-round applications; (4) Variable frequency drives for all air handling fan motors; (4) Premium efficiency multiple boiler system; and (5) Lighting control system. The annual energy cost savings due to these measures will be about $165,000. The estimated annual energy savings are two million kWhrs electric, and 168,000 therms natural gas, the total of which is equivalent to 23,000 million BTUs per year. Put into the perspective of a typical office/light lab at SNL/NM, the annual energy savings is equal the consumption of a 125,000 square foot building. The reduced air emissions are approximately 2,500 tons annually.

More Details

Theoretical energy release of thermites, intermetallics, and combustible metals

Fischer, S.H.

Thermite (metal oxide) mixtures, intermetallic reactants, and metal fuels have long been used in pyrotechnic applications. Advantages of these systems typically include high energy density, impact insensitivity, high combustion temperature, and a wide range of gas production. They generally exhibit high temperature stability, and possess insensitive ignition properties. In this paper, the authors review the applications, benefits, and characteristics of thermite mixtures, intermetallic reactants, and metal fuels. Calculated values for reactant density, heat of reaction (per unit mass and per unit volume), and reaction temperature (without and with consideration of phase changes and the variation of specific heat values) are tabulated. These data are ranked in several ways, according to density, heat of reaction, reaction temperature, and gas production.

More Details

Molecular recognition in gas sensing: Results from acoustic wave and in-situ FTIR measurements

Ricco, A.J.

Surface acoustic wave (SAW) measurements were combined with direct, in-situ molecular spectroscopy to understand the interactions of surface-confined sensing films with gas-phase analytes. This was accomplished by collecting Fourier-transform infrared external-reflectance spectra (FTIR-ERS) on operating SAW devices during dosing of their specifically coated surfaces with key analytes.

More Details

Reduction of Np(VI) and Pu(VI) by organic chelating agents

Moore, Robert C.

The reduction of NpO{sub 2}{sup 2+} and PuO{sub 2}{sup 2+} by oxalate, citrate, and ethylenediaminetetraacetic acid (EDTA) was investigated in low ionic strength media and brines. This was done to help establish the stability of the An(VI) oxidation state depended on the pH nd relative strength of the various oxidation state-specific complexes. At low ionic strength and pH 6, NpO{sub 2}{sup 2+} was rapidly reduced to form NpO{sub 2}{sup +} organic complexes. At longer times, Np(IV) organic complexes were observed in the presence of citrate. PuO{sub 2}{sup 2+} was predominantly reduced to Pu{sup 4+}, resulting in the formation of organic complexes or polymeric/hydrolytic precipitates. The relative rates of reduction to the An(V) complex were EDTA > citrate > oxalate. Subsequent reduction to An(IV) complexes, however, occurred in the following order: citrate > EDTA > oxalate because of the stability of the An(VI)-EDTA complex. The presence of organic complexants led to the rapid reduction of NpO{sub 2}{sup 2+} and PuO{sub 2}{sup 2+} in G-Seep brine at pHs 5 and 7. At pHs 8 and 10 in ERDA-6 brine, carbonate and hydrolytic complexes predominated and slowed down or prevented the reduction of An(VI) by the organics present.

More Details

Testing, expanding and implementing pollution prevention tools for environmental restoration and decontamination and decommissioning

Roybal, J.A.

Pollution Prevention (P2) programs and projects within the DOE Environmental Restoration (ER) and Decontamination and Decommissioning (D and D) Programs have been independently developed and implemented at various sites. As a result, unique, innovative solutions used at one site may not be known to other sites, and other sites may continue to duplicate efforts to develop and implement similar solutions. Several DOE Program offices have funded the development of tools to assist ER/D and D P2 projects. To realize the full value of these tools, they need to be evaluated and publicized to field sites. To address these needs and concerns, Sandia National Laboratory (SNL/NM), Los Alamos National Laboratory (LANL), and the Oak Ridge Field Office (DOE-OR) have teamed to pilot test DOE training and tracking tools; transfer common P2 analyses between sites, and evaluate and expand P2 tools and methodologies. The project is supported by FY 98 DOE Pollution Prevention Complex-Wide Project Funds. This paper presents the preliminary results for each of the following project modules: Training, Waste Tracking Pilot, Information Exchange, Evaluate P2 Tools for ER/D and D, Field Test of P2 Tools; and DOE Information Exchange.

More Details

Sandia bicycle commuters group -- pollution prevention at Sandia National Laboratories, New Mexico

Wrons, Ralph J.

The Sandia Bicycle Commuters Group (SBCG) formed three years ago for the purpose of addressing issues that impact the bicycle commuting option. The meeting that launched the SBCG was scheduled in conjunction with National Bike-to-Work day in May 1995. Results from a survey handed out at the meeting solidly confirmed the issues and that an advocacy group was needed. The purpose statement for the Group headlines its web site and brochure: ``Existing to assist and educate the SNL workforce bicyclist on issues regarding Kirtland Air Force Base (KAFB) access, safety and bicycle-supporting facilities, in order to promote bicycling as an effective and enjoyable means of commuting.`` The SNL Pollution Prevention (P2) Team`s challenge to the SNL workforce is to ``prevent pollution, conserve natural resources, and save money``. In the first winter of its existence, the SBCG sponsored a winter commute contest in conjunction with the City`s Clean Air Campaign (CAC). The intent of the CAC is to promote alternative (to the single-occupant vehicle) commuting during the Winter Pollution Advisory Period (October 1--February 28), when the City runs the greatest risk of exceeding federal pollution limits.

More Details

Contact force modeling between non convex objects using a nonlinear damping model

Lafarge, Robert A.

At Sandia National Laboratories, the authors are developing the ability to accurately predict motions for arbitrary numbers of bodies of arbitrary shapes experiencing multiple applied forces and intermittent contacts. In particular, they are concerned with the simulation of systems such as part feeders or mobile robots operating in realistic environments. Preliminary investigation of commercial dynamics software packages led us to the conclude that they could use a commercial code to provide everything they needed except for the contact model. They found that ADAMS best fit the needs for a simulation package. To simulate intermittent contacts, they need collision detection software that can efficiently compute the distances between non-convex objects and return the associated witness features. They also require a computationally efficient contact model for rapid simulation of impact, sustained contact under load, and transition to and from contact conditions. This paper provides a technical review of a custom hierarchical distance computation engine developed at Sandia, called the C-Space Toolkit (CSTk). In addition, the authors describe an efficient contact model using a non-linear damping term developed at Ohio State. Both the CSTk and the non-linear damper have been incorporated in a simplified two-body testbed code, which is used to investigate how to correctly model the contact using these two utilities. They have incorporated this model into ADAMS SOLVER using the callable function interface. An example that illustrate the capabilities of the 9.02 release of ADAMS with the extensions is provided.

More Details
Results 91101–91200 of 96,771
Results 91101–91200 of 96,771