Publications

A computer controlled servo-hydraulic mechanical test system has been configured to conduct automated fatigue crack growth testing. This provides two major benefits: it allows continuous cycling of specimens without operator attention over evenings and weekends; and complex load histories, including random loading and spectrum loading, can be applied to the specimens to simulate cyclic loading of engineering structures. The software is written in MTS Multi-User Basic to control test machine output and acquire data at predetermined intervals. Compact tension specimens are cycled according to ASTM specification E647-86. Fatigue crack growth is measured via specimen compliance during the test using a compliance/crack length calibration determined earlier by visual crack length measurements. This setup was used to measure crack growth rates in 6063 aluminum alloy for a variety of cyclic loadings, including spectrum loads. Data collected compared well with tests run manually. 13 figs.

A liquid-metal pool-boiler solar receiver has been proposed to link a paraboloidal-dish concentrator to a Stirling heat engine operating in the temperature range 700--800/degree/C. Preliminary to the construction of a full-scale receiver of this type, a bench-scale version using liquid sodium was designed, built and tested. Conclusions drawn from the test included: (1) boiling instability will occur in the full-scale receiver unless special measures are taken, (2) boiling was stabilized in the bench-scale receiver after the addition of ''artificial cavities'', but other stabilizing influences may also have been present, (3) ''hot restarts'' can under some circumstances lead to unacceptably-high incipient-boiling superheats, (4) no thermal-fatigue damage was evident after 100 hours of boiling interspersed with 24 cooldown periods, (5) 0.01-inch-diameter sheathed thermocouples used to provide an estimate of heated-wall temperature survived over 100 hours at 830/degree/C, and (6) other instrumentation and control techniques that were tested were shown to be appropriate for future full-scale receiver tests. 27 refs., 24 figs., 4 tabs.

A program has been written that allows us to predict the trace-to- trace cross-coupling on printed circuit boards for many geometries of practical interest. It combines multiconductor transmission line analysis with circuit analysis in the time domain. Multiple sections of uniform lines, of varying number and characteristics, can be interconnected by passive circuit elements. These circuit elements may represent physical components or the effects of discontinuities in the lines. These predictions were compared with measurements for simple geometries, with good agreement in both waveshape and amplitude. The major discrepancies were in the amplitudes of fast rising spikes and are probably due to the fact that the predictions did not account for the increasing attenuation at high frequencies. 10 refs., 12 figs.

This report presents preliminary analyses of the Nunnally mass launcher. The Nunnally launcher is much like ones described in US Patents 1,370,200; 1,421,435; and 1,422,427 which were issued to A.L.O. Fauchon-Villeplee in the period 1917--1922. A discussion of why a high conductivity projectile impulsively accelerated in a uniform transverse B-field does not experience a drag force, even for very large magnetic Reynolds numbers (R/sub m/ = 10/sup 2/ /minus/ 10/sup 4/) is also presented. 1 ref., 7 figs.

The thermomechanical fatigue behavior of solder joints is a critical reliability issue in electronic packaging. A need exists for a thorough metallurgical understanding of solder joints in conditions of thermal fatigue. This paper presents a method to test solder joints under conditions of thermomechanical fatigue. This method involves simultaneous imposition of temperature and strain cycles on discrete solder joints in a shear orientation. The stress, microstructure, and number of cycles to failure are monitored. Cycles to failure are determined by a continuous electrical resistance detection method. 60Sn-40Pb and 40Sn-40In-20Pb solder joints were tested using this new method at 20% shear strain. 4 refs., 7 figs.

This report provides an introduction to the capabilities of a new experimental test system recently acquired by Department 1830 and installed into the Organization 1000 bay of the microelectronics Development Laboratory, Building 858. This device - the Nano..delta..Indenter/Trademark/ - is a state of the art ultra-low load indentation hardness tester. It is a computer-controlled load and depth sensing instrument with depth resolution of 0.2 nm and load resolution of 0.3 ..mu..N. Initial testing has now been performed using this machine, verifying that it will be a unique addition to our existing mechanical test capabilities. 3 refs., 8 figs.

From the beginning of the geothermal development program, Sandia has performed and supported research into polycrystalline diamond compact (PDC) bits. These bits are attractive because they are intrinsically efficient in their cutting action (shearing, rather than crushing) and they have no moving parts (eliminating the problems of high-temperature lubricants, bearings, and seals.) This report is a summary description of the analytical and experimental work done by Sandia and our contractors. It describes analysis and laboratory tests of individual cutters and complete bits, as well as full-scale field tests of prototype and commercial bits. The report includes a bibliography of documents giving more detailed information on these topics. 26 refs.

Analyses of the final state of collapse of various types of contact-handled waste drums are required to assess of the performance of the waste storage areas in the Waste Isolation Pilot Plant. To provide data for calculations, tests must use simulated, instead of actual waste. Data on the contents of the principal categories of contact-handled transuranic waste from the Idaho National Engineering Laboratory were used to define standard compositions of simulated waste. Categories of baseline waste will be created by mixing appropriate amounts of the simulants together. Selection of materials is discussed. Methods for estimating the consolidation characteristics of simulated waste are also described. Theoretical solid densities, theoretical solid compressibilities, and initial void volumes of various waste components are estimated, and a method for estimating consolidation curves in the absence of experimental data is described. 9 refs., 14 figs., 11 tabs.

The research and development described in this document were conducted within the US Department of Energy's Solar Thermal Technology Program. The goal of the Solar Thermal Technology Program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. This bibliography cites, with a few additions, all the documents that were published by, or sponsored by, Sandia National Laboratories in support of the Department of Energy's Solar Thermal Technology Program and its Distributed Receiver Project. The timing of this updated bibliography is important because it marks the end of an era in which distributed receiver and central receiver research and development were pursued separately. At the beginning of fiscal year 1989, the Department of Energy initiated a restructured solar thermal research and development strategy. The new program is mission oriented, with core technology development activities supporting the missions. For instance, the advanced electric technology mission has an objective to organize industry, user, and government consortia that will field competitive next-generation solar thermal electric system experiments within five years--regardless of whether the systems are distributed or central receivers; and the concentrator development core activity will develop optical materials and concentrators regardless of application.

This document serves as the proceedings for the annual project review meeting held by Sandia's Photovoltaic Cell Research Division and Photovoltaic Technology Division. It contains information supplied by each organization making a presentation at the meeting, which was held 11-13 July 1989 at the Marriott Hotel in Albuquerque, NM. Information supplied by other Sandia contractor and single-page data sheets generated by the cognizant Sandia Technical Liasion for each contract are also included. Sessions were held to discuss national and international photovoltaic programs, one-sun crystalline silicon cell research, concentrator silicon cell research, concentrator III-V cell research, and concentrating collector development.

The Center for Compound Semiconductor Technology (CCST) was formed within the Solid-State Sciences Directorate at Sandia National Laboratories in 1988, as the culmination of a long-term thrust into compound semiconductor research and technology that began about ten years ago. At that time, it was realized that electronic and optoelectronic devices based on compound semiconductors would be necessary for photonic applications, and that they could provide greater radiation hardness, higher speed, and higher operating temperatures than comparable silicon devices and circuits. It was also realized that a successful program would require the development and integration of materials growth and processing capability, solid-state physics research, and device engineering. The program at Sandia grew steadily from the purchase of the first Molecular beam Epitaxy (MBE) system in 1981, and the discovery of strained-layer superlattices in 1982, to the completion of the Compound Semiconductor Research Laboratory in 1989. To more formally organize this effort, Sandia established the CCST in 1988, aided by $10M of funding from DARPA. The CCST comprises most of the compound semiconductor research and development activities in the Solid-State Sciences Directorate. Ongoing programs are funded by the DOE Office of Military Applications, DOE Basic Energy Sciences, DOE Conservation and Renewable Energy, and the Department of Defense. 15 figs.

Sealing a nuclear waste repository in partially saturated tuff presents unique challenges to assuring performance of sealing components. Design and performance of components for sealing shafts, ramps, drifts, and exploratory boreholes depend on specific features of both the repository design and the site; of particular importance is the hydrologic environment in the unsaturated zone, including the role of fracture flow. Repository design features important to sealing of a repository include the size and location of shaft and ramp accesses, excavation methods, and the underground layout features such as grade (drainage direction) and location relative to geologic structure. Uncertainties about seal components relate to the postclosure environment for the seals, the emplacement methods, the material properties, and the potential performance of the components. An approach has been developed to reduce uncertainties and to increase confidence in seal performance; it includes gathering extensive site characterization data, establishing conservative design requirements, testing seal components in laboratory and field environments, and refining designs of both the seals and the repository before seals are installed. 9 refs., 5 figs., 2 tabs.

Sandia National Laboratories: The Postwar Decade is organized into two major sections: Part 1: Heritage'' and Part 2: Nuclear Ordnance Engineer for the Nation.'' Within this general structure, the narrative connects a series of subjects, beginning with a Prologue that surveys the national and international events leading to development of the atomic bomb and establishment of the national laboratory complex under the Manhattan Engineer District.

Recent experiments on Lawrence Livermore's ATA indicate that there may be problems with the IFR (Ion Focused Regime) transport of the relativistic electron beam (REB) through the ATA accelerator. For beam currents greater than about 7-kA, the beam is observed to be inverse-tailored with the beam radius increasing from beam head to tail. This inverse-tailoring is considered unfavorable for endo- atmospheric beam propagation. An unusual feature of ATA's laser- produced IFR channel is that it has a rectangular cross-section. One possible explanation for the lack of good beam transport may be ion motion in the IFR channel which disrupts the tail of the beam. In this report an ATA-like electron beam, propagating on a laser-ionized rectangular IFR channel is simulated using the 3-D magnetostatic code BUCKSHOT. The simulations demonstrate that non-axisymmetric ion motion, similar to the ion hose instability, can produce an inverse- tailored electron beam similar to those found in the experiment. The simulation results should be relevant to upcoming TROLL experiments with a laser-ionized IFR channel, with several beam parameters similar to ATA's. 1 ref., 22 figs.

In late 1985, the International Atomic Energy Agency (IAEA) requested the US Program for Technical Assistance to IAEA Safeguards (POTAS) to provide a study which examined sealing concepts for application to spent fuel shipping casks. This request was approved, and assigned to Sandia National Laboratories (Sandia). In the course of this study, discussions were held with personnel in the International Safeguards Community who were familiar with the shipping casks used in their States. A number of shipping casks were examined, and discussions were held with two shipping cask manufacturers in the US. As a result of these efforts, it was concluded that the shipping casks provided an extremely good containment, and that many of the existing casks can be effectively sealed by applying the seal to the cask closure bolts/nuts.

A design for a photodetector quantum efficiency measurement test system is presented. The system hardware and control software are explained and the measurement theory is given. A brief discussion of the operation of the prototype is given. Finally, the article concludes with an example of a quantum efficiency measurement of a sample and a discussion of the errors involved in the measurement. 9 refs., 7 figs.

The Magma Energy Program of the US Department of Energy, Geothermal Technology Division, is planning to begin drilling a deep (6 km) exploration well in Long Valley Caldera, California, in September 1988. The location of the well is in the central part of the caldera, coincident with a large number of shallow (5-7 km) geophysical anomalies identified through many independent investigations. Results from the hole will permit the following: direct investigation of the geophysical anomalies interpreted to be magma; investigation of the patterns and conditions of deep fluid circulation and heat transport below the caldera floor; determination of the amount of collapse and subsequent resurgence of the central portion of Long Valley caldera; and determination of the intrusion history of the central plutonic complex beneath the caldera, and establishment of the relationship of intrusive to eruptive events. The hole will thus provide a stringent test of the hypothesis that magma is still present within the central plutonic complex. If the interpretation of geophysical anomalies is confirmed, the hole will provide the first observations of the environment near a large silicic magma chamber. 80 refs., 7 figs., 2 tabs.

A computer code for analyzing four-gage Anelastic Strain Recovery (ASR) data has been modified for use on a personal computer. This code fits the viscoelastic model of Warpinski and Teufel to measured ASR data, calculates the stress orientation directly, and computes stress magnitudes if sufficient input data are available. The code also calculates the stress orientation using strain-rosette equations, and its calculates stress magnitudes using Blanton's approach, assuming sufficient input data are available. The program is written in FORTRAN, compiled with Ryan-McFarland Version 2.4. Graphics use PLOT88 software by Plotworks, Inc., but the graphics software must be obtained by the user because of licensing restrictions. A version without graphics can also be run. This code is available through the National Energy Software Center (NESC), operated by Argonne National Laboratory. 5 refs., 3 figs.

The Sandia downhole seismic source produces vertically polarized shear waves of variable frequency. While the source has been successfully tested in the field, the practicality of the source for reservoir characterization has not been established. The principal question is whether sufficient power can be supplied to the source through practical means so that sufficient energy output can be maintained. Here we investigate the feasibility of several schemes to provide power to the Sandia downhole seismic source. 4 refs., 5 figs., 5 tabs.

Traditionally, pyrolysis combined with infrared, IR, detection of the decomposition products for the analysis of small (<1 mg) samples has been limited due to the size and geometry of commercially available pyrolysis chambers. To reduce the sample size requirements for pyrolysis-IR a system has been designed and built that allows various microgram sized polymer samples to be examined. The design incorporates a commercial pyrolysis system with a small chamber built from readily available parts. Minimal modifications of these components are required to build the system. The micropyrolyzer has been used to successfully identify various filled epoxy samples, such as three Epon 828 samples: 0.46 mg of alumina filled; 0.15 mg of mica filled; and 0.28 mg of glass microballoon, GMB, filled. 7 refs., 6 figs.

The fracture toughness of several ductile cast iron (DCI) alloys has been calculated according to two versions of the ASTM Standard covering the determination of J/sub Ic/. The original version (ASTM E 813-81) had previously been used to establish the relationship between ferritic DCI alloys and the graphite nodule spacing. The J/sub Ic/ values were recalculated by the methods of the revised version of the ASTM Standard (ASME 813-87), and were found to be 5 to 8% higher than those determined by the original standard. A linear regression analysis was used to reaffirm that the fracture toughness is directly related to the graphite nodule size or spacing. 6 refs., 8 figs., 3 tabs.

The lightning literature extant through the end of 1988 has been reviewed and used to develop an updated generic, or baseline, direct-strike lightning environment for nuclear weapon Stockpile-to-Target Sequence documents. The supporting rationale for recommended changes is given, along with a discussion of the interpretation of the environment for weapon nuclear safety assessment. 13 refs., 2 tabs.

An initial feasibility study has been completed on the ultrasonic welding of Tophet C (Ni-24 Fe-16 Cr) bridgewire to Hastelloy C-276 (Ni-16 Cr-15 Mo-4 W) pin material. A key feature of this work is that it employed a hybrid microcircuitry ultrasonic wire bonder. Much greater productivity can be expected from this process compared with traditional bridgewire welding methods. Three different ultrasonic tool designs were investigated. After selection of the best design, pull test data were acquired for both the 1st and 2nd weld locations in both heel and toe directions. Values up to 94% of the bridgewire tensile strength were obtained. With the equipment used both raised and flat bridgewire configurations are possible. While much work is still necessary to prove in the process for production applications, the work completed to date indicates the ultrasonic welding process merits further investigation. 6 figs.

Sandia National Laboratories (SNL), Albuquerque is located south of Albuquerque on Kirtland Air Force Base. Because radionuclides are potentially released in small quantities from its research activities, SNL, Albuquerque has a continuing environmental monitoring program which analyzes for cesium-137, tritium, uranium, alpha emitters, and beta emitters in water, soil, air, and vegetation. A total of 5.23 curies of argon-41 were released as a result of SNL, Albuquerque operations in 1988. The albuquerque population received an estimated 0.04 person-rem from airborne radioactive releases, whereas it received greater than 44,500 person-rem from naturally occurring radionuclides. A nonradioactive effluent monitoring program at SNL, Albuquerque includes groundwater, stormwater and sewage monitoring. Results indicate that the groundwater has not been impacted by the chemical waste landfill. Preliminary testing of stormwater showed that no pollutants were above minimum detectable levels. A program to investigate potential remedial action sites has been started. 47 refs., 12 figs., 19 tabs.

The Tonopah Test Range is located about 140 air miles north of Las Vegas, Nevada, and covers 624 square miles within the Nellis Air Force base Bombing and Gunnery Range. The range is used for various USDOE and USDOD program tests that are critical to national defense. Activities that affect the environment are mainly road construction, preparation of instrumentation sites, and disturbance of the terrain from weapons testing. Monitoring of the test range is done routinely by the US Environmental Protection Agency (EPA) to supplement Sandia's monitoring effort associated with Sandia test activities. EPA monitoring results for 1988 indicate that test range operations do not adversely affect the off-site environment or the public. 14 refs., 2 figs., 11 tabs.