A novel optical based RF beam steering system is proposed for phased-array antenna systems. The system, COMPASS (Coherent Optical Monolithic Phased Array Steering System), is based on optical heterodyning employed to produce microwave phase shifting. At the heart of the system is a monolithic Photonic Integrated Circuit (PIC) constructed entirely of passive components. Microwave power and control signal distribution to the antenna is accomplished by optical fiber, thus separating the PIC and its control functions from the antenna. This approach promises to reduce size, weight, and complexity of future phased-array antenna systems.
This update discusses modifications of PRONTO 3D tailored to the design of fast burst nuclear reactors. A thermoelastic constitutive model and spatially variant thermal history load were added for this special application. Included are descriptions of the thermoelastic constitutive model and the thermal loading algorithm, two example problems used to benchmark the new capability, a user's guide, and PRONTO 3D input files for the example problems. The results from PRONTO 3D thermoelastic finite element analysis are benchmarked against measured data and finite difference calculations. PRONTO 3D is a three-dimensional transient solid dynamics code for analyzing large deformations of highly non-linear materials subjected to high strain rates. The code modifications are implemented in PRONTO 3D Version 5.3.3. 12 refs., 30 figs., 9 tabs.
A study was conducted to determine the feasibility of coating gold plated kovar lids with colloidally bonded aluminum oxide. Radiation that is incident on a gold plated lid generates a large number of photoelectrons. These electrons can enhance the damage to microelectronic devices and circuits (ICs). The primary purpose of the coating is to stop the electrons emitted from the lid that would otherwise increase the damage to the IC. A coating system consisting of {approximately}95 wt % alumina (0.5 {mu}m particles) and {approximately}5 wt % colloidal silica (10 nm particles) was developed. The coating was applied to the lids as an aqueous suspension which was then dried to form a porous coating. Coating processing conditions were optimized so that crack-free, uniform coatings with the required thickness ({approximately}80 {mu}m) could be consistently produced. Preliminary data have indicated that the coated lid can be attached to the IC package using current belt furnace sealing procedures. The adhesion and mechanical integrity of the coatings were evaluated by submitting coated lids to centrifuge and shock testing. Selected coatings successfully withstood the shock test and 85% were undamaged after being subjected to an acceleration of 30,000 g's. Several types of radiation tests were performed to determine the effectiveness of the coating to stop electron penetration. Evaluation testing included gamma dose enhancement and X- ray induced photocurrent enhancement. The results for lids with coatings 80 or 150 {mu}m thick were compared with results for uncoated kovar and ceramic lids. 6 refs., 6 figs.
This report documents the as-built operational performance of Sandia's Severe Electrostatic Discharge Tester Version-3 (SSET-3) SN:2 and lists the hardware and additional documentation delivered to Division 2174 on July 31, 1991. (The supplied items are listed.) The primary emphasis of this report is to provide a qualitative and quantitative evaluation of the SSET against requirements derived from the Severe Human Body ESD model (SHBESD) (1), which is defined in terms of an equivalent circuit (Figure 1.1) and a short-circuit current waveform (Figure 1.2). This report also presents supporting information on the calibration and verification of ancillary equipment used to assess the operation of the SSET. While the documentation of the verification and calibration of ancillary equipment is somewhat lengthy, it is considered necessary because the SSET may be used in situations where its output characteristics will be critically scrutinized. Thus, the supporting documentation is necessary to lend credibility to the performance/verification measurements made on the SSET. 5 refs., 36 figs.
This document serves as the proceedings for the manual project review meeting held by Sandia's Photovoltaic Technology Research Division. It contains information supplied by each organization making a presentation at the meeting, which was held July 30 through 31, 1991 at the Sheraton Hotel in Albuquerque, New Mexico. Sessions were held to discuss national photovoltaic programs, one-sun crystalline silicon cell research, concentrator silicon cell research, and concentrating collector development.
One decade ago, Sandia National Laboratories designed and developed a nonpyrotechnic smoke generator capable of producing large quantities of low corrosivity, low toxicity chemical smoke to be used as a visual obscurant in access delay applications. Utilizing the same chemistry, a proof-of-concept advanced smoke generator is presently being tested. The testing is being conducted to evaluate two new concepts providing unique capabilities. Hemispherical stainless steel bladders are installed in spherically shaped chemical storage reservoirs. This provides positive displacement of the chemicals and permits orientation insensitive operation. Also, a specially designed nozzle/valve is being evaluated as a means of providing a multiple initiation capability. Cyclic operation could be accomplished via time delay circuitry, sensor input, or on demand from the control console. These new capabilities provide distinct advantages. Some advantages may be longer obscuration times, optimal volume obscuration, easier facility sizing, no organic seals in contact with the stored chemicals, and elimination of the requirement to use ultrahigh purity nitrogen as a propellant.
NMR and NQR reveal substantial structural changes in the metallic phase of La2CuO4+δ which occur below 220 K. The oxygen octahedra in the metallic phase are not tilted at phase separation; upon cooling to 40 K considerable tilt has developed. The low temperature structure is highly disordered.
Previously, we have designed 3-level filters (suitable for implementation on magneto-optic spatial light modulators) to maximize the output signal-to-noise ratio (SNR) and to separately maximize Peak-to-Correlation Energy (PCE) that measures the correlation peak sharpness. In practice, we want the correlation peaks to be sharp (i.e., large PCE) as well as noise-tolerant (i.e., large SNR). In this paper, we will present a new method to optimally combine these two desirable properties into a single optimization procedure. Similar methods to trade off SRN versus Peak Efficiency and PCE versus Peak Efficiency will be presented. Both simulation and experimental results will be included.
We have studied triggering of fuel-coolant interactions, the work performed against the surrounding coolant during the interaction, and the generation of hydrogen produced by melt water chemical reactions with laboratory-scale experiments. We used single drops of three core-melt simulants: (a) molten stoichiometric thermite-generated iron-aluminum oxide melts to simulate the core-melt material that might be produced in the severe accident of an oxide fueled reactor; (b) molten aluminum to simulate melt that might be produced in the severe accident of a nonpower reactor; and (c) an intermediate material, aluminum-enriched iron aluminum oxide thermite, that might simulate severe meltdown of an oxide-metal dispersion fuel (cermet). As a result of these experiments, we have concluded that the peak pressure (or impulse) of the transient is not a governing parameter for the triggering of steam explosions of single drops of melt. We have observed maximum pressure-volume work outputs produced by the aluminum-rich and stoichiometric thermite melts of about 70 and 25 J/g of melt; the corresponding values for molten aluminum at 1273 and 1473 K are about 14 and 21 J/g of melt. The extent of metal-water reaction for the stoichiometric and aluminized melts were 13 and 19%. The aluminum melts at 1273 and 1473 K produced approximately 1 and 3% metal-water reaction.
Sandia National Laboratories is very active in developing multi-dimensional, multi-material shock wave physics codes. One example is the state-of-the-art, three-dimensional Eulerian code CTH which is used at numerous government and university sites. CTH is being ported to both Single Instruction Multiple Data (SIMD) and Multiple Instruction Multiple Data (MIMD) massively parallel computers. The next-generation arbitrary-Lagrangian-Eulerian code RHALE is under development. This paper will discuss these codes. CTH is an Eulerian code for modelling multi-dimensional, multi-material, large deformation, strong shock physics. Finite-volume numerical schemes are used with one-dimensional, two-dimensional and three-dimensional meshes. CTH has models for elastic-plastic materials, porous materials, high explosive detonation, fracture, and energy deposition. Several analytic equations of state are available including ideal gasses, Jones-Wilkins-Lee high explosive reaction products, Mie-Griineisen solids, and sophisticated multi-phase models that are valid for a very broad range of densities and temperatures. Tabular equations of state are also available. Second-order accurate advection schemes are used to minimize the dispersion found in Eulerian codes. Very large three-dimensional calculations may be run efficiently on a CRAY supercomputer because the code is highly vectorized and the data bases reside on the Solid State Disk (SSD). Data bases larger than one hundred million words are commonly used. Sophisticated color post-processing software was developed to aid in interpreting the results. Much of CTH has been ported to both SIMD and MIMD massively parallel computers. The two-dimensional version is running three times faster than a single CPU CRAY/YMP on the 16k node SIMD Connection Machine and five times faster on the 1024 node nCUBE2 MIMD computer. Both of the massively parallel computers can be expanded by a factor of four to eight yielding a system an order of magnitude faster than a CRAY. The next-generation, three-dimensional arbitrary-Lagrangian-Eulerian code RHALE is under development. Finite element techniques are used to integrate the physics through time. The mesh will move with the material (Lagrangian mesh) until the distortion becomes excessive and then the nodes are automatically repositioned to smooth the mesh and improve the accuracy (Eulerian mesh). Node motion occurs only where the distortion is excessive. This results in a code with the best features of both Lagrangian and Eulerian codes. Arbitrary-connectivity meshes are used to generate very complicated and sophisticated meshes. However, this dramatically increases the complexity of the Eulerian algorithms.
The hypervelocity impact of a particle on a surface generates a jet of shocked material which is thrown from the impact site. A simple analytic model has been developed to obtain expressions for the evolution of this jet of ejecta. The analysis is based on applying the conservation equations of mass and momentum to the problem of a normal impact of a sphere against a semi-infinite flat target. Expressions are developed for the evolution of the jet velocity, jet release point and the locus of points which describe the ejecta envelope. These analytical ejecta profiles are compared with high speed photographs of impact jet formation.
Many robot control algorithms for high performance in-contact operations including hybrid force/position, stiffness control and impedance control approaches require the command the joint torques. However, most commercially available robots do not provide joint torque command capabilities. The joint command at the user level is typically position or velocity and at the control developer level is voltage, current, or pulse-width, and the torque generated is a nonlinear function of the command and joint position. To enable the application of high performance in-contact control algorithms to commercially available robots, and thereby facilitate technology transfer from the robot control research community to commercial applications, an methodology has been developed to linearize the torque characteristics of electric motor-amplifier combinations. A four degree of freedom Adept 2 robot, having pulse-width modulation amplifiers and both variable reluctance and brushless DC motors, is converted to operate from joint torque commands to demonstrate the methodology. The commercial robot controller is replaced by a VME-based system incorporating special purpose hardware and firmware programmed from experimental data. The performance improvement is experimentally measured and graphically displayed using three-dimensional plots of torque vs command vs position. The average percentage torque deviation over the command and position ranges is reduced from as much as 76% to below 5% for the direct-drive joints 1, 2 and 4 and is cut by one half in the remaining ball-screw driven joint 3. Further, the torque deviation of the direct-drive joints drops below 2.5% if only the upper 90% of the torque range is considered. 23 refs., 20 figs., 2 tabs.
The mechanical behavior of crushed natural rock salt is of concern to the Waste Isolation Pilot Plant (WIPP) Project because excavated salt is a candidate material for use as backfill around the waste packages and in storage rooms, shafts and other underground openings. To complement existing studies on the compaction behavior of dry and damp (i.e., unsaturated) crushed rock salt under hydrostatic compression, we initiated an extensive experimental program to evaluate (1) the effect of brine-saturation on the consolidation rates and terminal densities of crushed salt subjected to hydrostatic compression, and (2) the influence of small deviatoric stresses on the consolidation rate damp crushed rock salt. This investigation is incomplete, and laboratory facilities are limited, therefore, in this report we review available results, in order to make available preliminary estimates of the effects of brine-saturation and shear stress on consolidation. Experiments with brine were carried out under nominally drained conditions. Experiments completed to data include five hydrostatic compaction tests on brine-saturated samples, run at pressures ranging from 1.72 to 10.34 MPa, and two prototype shear consolidation experiments run at a mean stress of 3.45 MPa and a stress difference of 0.69 MPa. Both sets of experiments were run at 20{plus minus}0.5 {degrees}C. Although the experiments on brine-saturated crushed rock salt exhibit several discrepancies, we can draw the following conclusions. (1) Though effects associated with brine-saturated apparently have a retarding effect on consolidation, rates are reduced by less than an order of magnitude when compared with unsaturated specimens. Despite saturation, high fractional densities (>0.95) are attainable even on laboratory time scales using pressures well below lithostatic at the WIPP ({approx} 15 MPa). 23 refs., 26 figs., 5 tabs.
The MERLIN 2 program is designed to transfer data between finite element meshes of arbitrary geometry. The program is structured to accurately interpolate previously computed solutions onto a given mesh and format the resulting data for immediate use in another analysis program. Data from either two-dimensional or three-dimensional meshes may be considered. The theoretical basis and computational algorithms used in the program are described and complete user instructions are presented. Several example problems are included to demonstrate program usage. 13 refs. 15 figs.
This report describes the phenomenological equations and the numerical procedures used by the CONTAIN 1.1 code to determine the conditions within nuclear power plant containment during a severe accident. The CONTAIN detailed models provide the capability to mechanistically calculate the containment internal thermalhydraulic conditions and the amount of radioactive matter that would be released to the environment if there were a leak from the containment. Note that the CONTAIN models can be verified by comparing the code calculations to experimental results. The models described include those to account for the flows of mass and energy between containment compartments, the exchange of energy between the atmosphere and heat structures, the thermodynamic conditions, the distributions of aerosols, the decay and transport of fission products, the deflagration of hydrogen and carbon monoxide, boiling water reactor suppression pool behavior, and engineering safety features, including a spray, fan coolers, and an ice condenser. These models are solved with implicit coupling, where appropriate, to obtain a stable and computationally efficient solution. 52 refs., 36 figs., 9 tabs.
The Primary Standards Laboratory (PSL) operates a system-wide primary standards and calibration program for the US Department of Energy, Albuquerque Operations Office (DOE/AL). The PSL mission is as follows: to develop and maintain primary standards; to calibrate electrical, physical, and radiation reference standards for customer laboratories (DOE/Al integrated contractors); to conduct technical surveys and audits of these laboratories; and to recommend and implement system-wide improvements. This report summarizes activities of the PSL for the second half of 1990 and provides information pertinent to the operation of the DOE/AL Standards and Calibration Program. Specific areas covered include development projects, improvement projects, calibration and special measurements, surveys and audits, and significant events. Activities in these areas have been at a lower than normal level because of response to increased Environment, Safety, and Health (ES H) concerns and preparation for a Tiger Team visit. Appendices include certifications and reports, commercial calibration laboratories, PSL memoranda, and National Institute of Standards and Technology ((NIST)--formerly the National Bureau of Standards (NBS)) test numbers.
Sandia National Laboratories has developed an advanced self-contained tracking control system for use with one- or two-axis tracking solar arrays. The SolarTrak system computes the sun's position based on the time and stored position data, and then controls two motors to point the tracker at the sun without using sun sensors. When used with a photovoltaic concentrator array, the system initially performs a self-alignment routine using array-generated current to locate the sun. The routine computes six numbers that are used during the normal operation to correct the array pointing for the tracker's installation misalignment. This enables the tracker to point accurately even with installation misalignments of up to several degrees. The SolarTrak system consists of a control board, which contains a Motorola 68HC11 microcontroller, a power supply board, motor-interface boards, and a hand-held user interface board, which contains a liquid-crystal display and an input keypad. This report contains a thorough discussion of the controller software and hardware, including control algorithms, parts lists and estimated costs (about $300 per system). The performance measured on two trackers is reviewed. Tracking accuracy was better than {plus minus}0.1{degrees} over a full day on one system. A thorough user's manual is included. Companies interested in licensing the technology should contact the Technology Transfer Division of Sandia National Laboratories. 20 refs., 53 figs., 5 tabs.
Simulated DHLW (Defense High Level Waste) package performance tests were carried out at the WIPP (Waste Isolation Pilot Plant) by emplacing a number of waste canisters containing electrical heaters into the floor of the mine. Peak temperatures were about 130{degrees}C, and the tests ran for three years. During this time, an unanticipated large amount of water was collected from heater hole BO42. A study was, therefore, undertaken to determine if this fluid was derived from normal weep brines. This was accomplished by comparing the amount of salt deposited by the dried weep brines with the volume of condensed steam collected during the test. Documenting the post-test condition of the various backfills was the other objective of this report. In spite of being exposed to acidic vapors, the bentonite-sand backfill retained its mineralogic integrity. However, the bentonite-sand backfill compacted between the canister and the wall only achieved a density that was about three quarters that of a pore-free material. The bentonite backfill also showed evidence of hair-line cracks through which steam had left the vicinity of the canister. In contrast, compacted crushed salt backfill exhibited no evidence of through-going cracks and was compacted to better than 99% of that of pure nonporous sodium chloride. Thus, the seal provided by a crushed salt backfill appears to be superior to that provided by bentonite. 13 refs., 6 tabs.
This report provides system designers with basic human factors information and guidelines for designing and developing the software user interface. A brief discussion of the user interface design philosophy is presented, followed by an overview of the user interface options available (such as color and highlighting), candidate approaches, and discussion of general display concepts and user interface features. We have presented information to facilitate discussions of user interface options, to aid in making final user interface design decisions, and to further the refinement of the user interface. We provide a candidate questionnaire for evaluating your software user interface. 41 refs., 3 tabs.
We have conducted an extensive investigation of the split cavity oscillator (SCO) using particle-in-cell simulation. The goal of this work is to test and optimize an inverse diode rf convertor for use with a cylindrical SCO, while simultaneously determining factors that control rf extraction efficiency. We present results from simulations of several configurations including the SCO with inverse diode extractor, the SCO in conjunction with post-acceleration and inverse diode extraction, and the SCO, using electron beams with a variety of currents, voltages, and radii. 7 refs., 8 figs.
This report presents an assessment of ambient temperature rechargeable lithium batteries for electric vehicle applications. It was prepared for the Department of Energy, Office of Propulsion Systems. The status of development programs in industry and research laboratories was determined for several positive and negative electrode materials and for organic liquid and solid polymer electrolytes. Recommendations are suggested for future research and development activities. 217 refs.
The hydrodynamic blast created by the initiation of a 1 kev X-ray source from an arc-induced ionized gas column, involves density and temperature ratios of such magnitude that the strong shock theory of propagation from continuum fluid mechanics does not apply. Because these simulations occurs in a near vacuum, the continuum equations of motion break down and become invalid during the expansion process as the wavefront density decreases. This report summarizes an approximate treatment of the hydrodynamics of a strong explosion followed by an expanding wavefront in a near vacuum. The analysis was performed in support of the Saturn program to assist the test engineers in the design of a shroud which is optimized to receive the maximum cold X-ray radiation through its aperture while minimizing the hydrodynamic damage to the rest specimens. The analytical treatment uses mass conversion and the assumption of a liner velocity profile to assess the dynamic behavior of the developing wavefront. This technique provides a first estimate of the gas motion and pressure pulse and indicates some general trends of the hydrodynamic phenomenon. 9 refs., 16 figs., 1 tab.
NASA has proposed that the solar concentrator for the manned space station, referred to as the Solar Concentrator Advanced Development (SCAD) dish, undergo terrestrial testing prior to being deployed in space. Because reliable flight concentrator performance is so important, independent tests of the SCAD concentrator are needed to demonstrate the offset parabolic concept and validate the computer codes needed for predicting concentrator flux profile and power generating capability. This report documents the first phase of a three-phase project to test the SCAD concentrator on sun. The three phases of the project are (1) Feasibility of On-Sun Testing; (2) Detailed Design and Fabrication of Test Fixtures; and (3) Testing and Analysis of Results. The objectives of Phase 1 are to evaluate the feasibility of testing the concentrator on sun in a terrestrial environment and to determine the potential for accurately predicting its performance in space. The feasibility study includes: an evaluation of terrestrial structures to support and track the concentrator; an assessment of methods for protecting the concentrator from the environment when it is not on test; the selection of the most feasible support structure and protection system; an evaluation of the effects of terrestrial solar power levels and sunshapes on the verification of computer codes for predicting the on-orbit performance of the concentrator; the development of a preliminary test plan complete with procedures and instrumentation; and the development of schedule and cost estimates for Phases 2 and 3 of the project.
This report describes a computer-controlled densitometer and software designed for qualitative and semiquantitative analyses of photographically recorded atomic emission spectra. The instrument provides a number of operational features and unique capabilities for spectrochemical analyses. The purpose of this research was the evaluation of the automated densitometer system and computer algorithms for identifying and measuring atomic emission spectra from photographs. 11 refs., 10 figs., 5 tabs.
We have obtained Raman spectra of icosahedral boron-rich solids. The spectra of α-rhombohedral boron, boron arsenide, and boron phosphide are consistent with highly-ordered materials. Polarization studies have resulted in symmetry assignments for most of the Raman bands of α-rhombohedral boron. In contrast, the Raman spectra of the boron carbides reveal local substitutional disorder. They also change progressively as a function of carbon content. A structural model for the boron carbides has been developed to explain the Raman and infrared absorption spectra, x-ray data, and electrical and thermal transport properties. Raman spectra of boron carbide samples enriched in 10B, 11B, and 13C reveal details of the atomic motions. The vibrational frequencies and exceptionally narrow linewidths of certain Raman modes are discussed in terms of a ‘‘strong’’ bond model. In this model certain vibrational modes involving relatively stiff bonds between chain atoms, chain and icosahedral atoms, and atoms on different icosahedra are decoupled from the boride lattice by weak, intraicosahedral bonds.