Publications

As part of the Strategic Petroleum Reserve (SPR), the Weeks Island oil storage site is a converted salt mine that contains approximately 73 million barrels of oil overlying 0.5 million barrels of brine. The oil is contained on two levels of the converted mine which are connected by a number of shafts and openings. Oil recycle exercises are periodically conducted to test the oil fill and withdrawal systems in which oil is simultaneously injected and withdrawn from two different locations in the lower level, and brine may be transported around the lower level of the mine by the movement of the oil. 11 refs., 16 figs.

An expert system developed to provide assistance to those involved with the creation, modification, interpretation and maintenance of Sandia's Engineering Procedures is described. 6 refs., 2 figs.

The Engineering Graphics System (EGS) is a computer program for use on Digital Equipment Corporation VAXstation color workstations. Its purpose is to manage and plot sets of engineering analysis data for use in reports and presentations. It is capable of producing nearly any type of x-y plot from a set of tabulated data. After the plot curves have been retrieved from the tabulated data, EGS can be used to interactively modify the appearance of the plot for use in a report or presentation. Modifications appear on the workstation display exactly as they appear on final hardcopy, which avoids costly iterations. Hardcopy plots can be made on two different black and white laser printers and on two different color printers, and plots can be converted for use by the Interleaf technical publishing software. 222 figs.

Power deposition measurements have been carried out on the ALT-II toroidal belt pump limiter and the inner bumper limiter in TEXTOR for Ohmic, neutral beam and RF heated discharges. Two infrared cameras and the ALT-II thermocouple array indicate that {lambda}{sub E} remains unchanged (7 mm) in the presence of beams but increases to 10 mm with ICRH. The heating distribution is less uniform on the bumper limiter than on ALT-II, which potentially could explain the differences seen in graphite surface pumping. 9 refs., 3 figs., 1 tab.

The operation of TORE SUPRA at full power (25MW, 30s) has led to the design of a full set of actively pumped carbon limiters to remove at least 8MW and to partially control the particle balance. An interim version is now installed, composed of 5 vertical and one horizontal outboard (OPL) pump limiters, semi-inertially water cooled. The latter is a result of a collaboration between the US DOE and the Association EUR-CEA, it is fully instrumented and therefore can serve as a reference for the final design. Ohmic discharges (1.85T, 740kA, 8.5s) in helium have been used to test the thermal load on and the particle exhaust efficiency of the OPL. In these experiments the plasma is formed on the inner wall (R = 232 cm, a = 76 cm) and subsequently displaced (6 cm) outward, early on the current plateau, to lean on the OPL (R = 238 cm, a = 75 cm). In addition to the limiters above, a non-pumped outboard (ONLP) limiter of identical shape to the OPL served to produce similar discharges for better comparison and determination of particle control. A comparison is made hereafter of the thermal load and particle pumping effects on the OPL when the plasma is in contact either with the OPL/ONPL alone or with the OPL and the vertical limiters together. 3 refs., 1 fig., 2 tabs.

Particle collection, removal, and exhaust by the toroidal belt pump limiter ALT-III have been measured in deuterium discharges with co-, counter-, and balanced injection of 48 keV neutral hydrogen particles. Particle collection increases from 50-80 A to 150-320 A during 1.2 MW of co- or counter-injection or 2.4 MW of balanced injection. The removal rate for pumping at two of the eight blades (3 of 15 scoops) reaches 2.7 Torr-l/s with a removal efficiency of nearly 45%. Extrapolating these results to a full belt with 15 scoops and eight pumps yields 140 amps of removal. This compares favorably with the maximum injectable current of 50 A and suggests that ALT-II with full pumping can provide sufficient exhaust during NI heating. 4 figs.

The microstructure and mechanical properties of high purity aluminum implanted with 20 at. % oxygen to a depth of roughly 500 nm and subjected to various thermal histories have been examined. Transmission electron microscopy and Rutherford-backscattering spectrometry were used to characterize the depth and nature of the implanted zone. As implanted, the material appears to contain a homogeneous distribution of disordered precipitates with sizes of 1.5-3.5 nm. Annealing at 450 or 550{degree}C/1 hr induces ordering of the precipitates but only causes slight coarsening. Ultra-low load identation hardness testing was used to probe the mechanical response of the surface-modified material. The data from the hardness tests were interpreted through the use of a finite-element model; the results indicate the flow stresses of an implanted and annealed layer are as high as 1600 MPa. The as-implanted material is much harder, approaching 3300 MPa. The degree of strengthening expected for the as-implanted and post-annealed material on the basis of the observed microstructure was estimated using several micromechanical models, and the results conform to the findings from indentation testing. 9 refs., 5 figs.

It has been observed on TEXTOR that in low density discharges the electrons gain enough energy to emit relativistic synchrotron radiation in the 3--6 {mu}m IR-range, and this radiation is due to electrons with energies up to 30 MeV. The momentum in perpendicular direction amounts to about 1/10 of the longitudinal one. The total number of runaways is of the order of 10{sup 16} electrons, and they carry a current of about 20% of the total plasma current. 3 refs., 1 fig.

The surface properties of symmetric microphase separated diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA) were investigated using X-ray photoelectron spectroscopy (XPS), the specular reflectivity of neutrons and secondary ion mass spectrometry (SIMS). PS, the lower surface energy component, exhibited a preferential affinity for the free surface. For copolymers that are far from the bulk microphase separation transition (MST), the surface consists of a layer of pure PS. When the system is close to the MST the surface is a mixture of PS and PMMA. The PS surface excess can be described by a N-{sup 1/2} dependence, where N is the number if segments that comprise the copolymer chain. It is shown that the surface undergoes an ordering transition at a temperature T{sub s} that is above that of the bulk MST. The ordering of the bulk lamellar morphology is induced by an ordering at the surface. This is analogous to the ferromagnetic order observed in systems such as Gd at temperatures above the bulk Curie temperature. The results here are discussed in light of previous work on copolymer surfaces and in light of mean field theory. 31 refs., 8 figs.

Oxygen ion beam bombardment has been studied as a means for incorporating oxygen into thin films of Y-Ba-Cu-oxide either by enhancing the transport of oxygen to substrates during ion-beam sputtering, or by direct incorporation of oxygen by ion-assisted deposition. Optical emission spectroscopy was used to study the ion-beam bombardment of bulk superconducting targets as the oxygen content of the ion beam was varied between 0% (pure argon) and 100% oxygen. This showed that oxygen did not directly combine with metallic elements in the target to increase the oxygen content of the stream of particles moving toward the substrate. The oxygen content of the sputter beam did, however, change the relative emission intensity from the various target components. Addition of a second ion beam directing an oxygen beam toward the substrate as the film is grown, caused large variations in the stoichiometry of the deposited films. At low ion currents, no increase in the oxygen content of the films was detected, while at relatively high currents, the oxygen incorporation increased. However, the sputtering of the metallic components of the film increased, leading to very low growth rates. 8 refs., 5 figs.

Intense beams of light ions are being developed at Sandia National Laboratories as a promising driver option for Inertial Confinement Fusion (ICF) implosions. The Particle Beam Fusion Accelerator II (PBFA II) will provide the physics basis for light-ion-beam driven ICF targets. Recent progress made in ion beam generation focusing on PBFA II has led to a record 5.4 TW/cm{sup 2} peak focal intensity with {gt}80 kJ proton energy delivered to a 6-mm diameter sphere. The driver-development program on PBFA II is reviewed. A design concept for a light ion beam driver for the Laboratory Microfusion Facility is also presented. 34 refs., 9 figs., 1 tab.

In an earlier paper, we reported that it is possible to train a first-order multi-layer feedforward network with backpropagation to classify raw 8-bit images of vehicles. We concluded that a linear feedforward network is capable of within-class generalization when trained with perspective views taken every 10{degree}, but it is incapable of one-class generalization. This paper describes the results of a set of experiments to train a feedforward network with second-order inputs to perform one-class classification on image data. We compare the results of the first-order network and the second-order network and show that the second order network is better able to generalize as a one-class classifier. 7 refs., 6 figs.

Short communication.

Ion beam studies on radiation enhanced sublimation (RES) have shown that above 800{degree} C energetic ions incident on graphite produce erosion in the form of carbon atoms with thermal energies and that the erosion rate rises roughly exponentially with temperature. Until recently, the question remained whether RES would scale linearly with flux over three to four orders of magnitude to the plasma edge fluxes in CIT and ITER, where the predicted erosion rates would severely limit the designs for plasma-facing components. Also, RES and carbon self-sputtering may also be involved in the carbon blooms'' observed in TFTR and JET. The data reported here from PISCES, a plasma source at UCLA, are the first RES data at fluxes approaching the plasma edge conditions in a large tokamak and they show little reduction from a direct linear dependence upon flux. Erosion rates measured by weight loss are reported for POCO graphite exposed to helium plasmas for a temperature range from 900--2000{degree} C, ion energies of 30--300 eV, ion fluxes of 1--6 {times} 10{sup 18} cm{sup {minus}2} s{sup {minus}1}, densities of 2--10 {times} 10{sup 12} cm{sup {minus}3} and electron temperatures of 4-10 eV. For these conditions, the amount of redeposition and carbon self-sputtering was minimal. Over 1700{degree} C, there is evidence of electron emission from the sample. 26 refs., 4 figs., 1 tabs.

Silicon power diodes, transistors, thyristors and other devices can be damaged by elevated temperatures, temperature cycling, and radiation. In this paper we discuss the vulnerability of devices that integrate bipolar and MOSFET (metal-oxide-semiconductor-field-effect transistor) devices onto a single chip. Such devices offer the advantages of good current carrying capability that is characteristic of bipolar structures and high impedance control nodes that are characteristic of MOSFET devices. Devices located near a space-based fission power source will be subjected to high temperatures, temperature cycling, naturally occurring radiation, radiation from the reactor; and these devices may be subjected to radiation from or caused by weapons used to attack the power source. Damaging radiation includes electrons and protons trapped in naturally occurring radiation belts, electrons pumped into these belts as a result of nuclear explosions, cosmic rays, neutrons from the reactor, and high energy photons (gamma rays and x-rays). 3 refs., 2 figs.

We consider problems related to the computation of Hermite and Smith normal forms of integer matrices, and more generally matrices over a principal ideal ring. First, we show that if the matrix A is m {times} n, with rank m and integer entries bounded in absolute value by T, then the Hermite normal form can be computed in O(m{sup 2}nB(m log(mT))) bit operations, where B(t) denotes a function that bounds the time required to perform the extended Euclidean algorithm on two t bit integers. Furthermore we show that the Smith normal form can be computed in O(m{sup 3}nB(m log(mT))log(mT)) bit operations. In the second part of the paper we apply fast matrix multiplication techniques to the problem of triangularizing a matrix over a ring using elementary column operations. We also prove that matrix inversion and multiplication are equivalent in complexity over an arbitrary Principal Ideal Domain, generalizing a result of Bunch and Hopcroft. We then apply our general results to obtain an algorithm for triangularizing integer matrices that has a faster running timer than the known Hermite normal form algorithms. The triangular matrix that is computed has small entries like the Hermite normal form, and will suffice for many applications. In the last part of the paper, we discuss a probabilistic method for calculating Smith normal forms. 17 refs.

We have examined several crystals belonging to the Tl-2122 structure type (Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8} with c = 29{angstrom}), and have shown that cation solid solution occurs. Such cation disorder appears to be responsible for the observed small differences in lattice parameters reported by various investigators and to contribute towards the substantial variation in the superconducting transition temperatures. 10 refs., 2 tabs.

Nuclear power plants present the fire protection community with unique challenges. In addition to the traditional concerns of life safety and property loss prevention, nuclear safety analysts must also be concerned with the impact of fires on the safe operability of the nuclear reactor. Safe shutdown equipment must be protected from fire damage. When nuclear power plants were first designed and built, fire safety considerations were based primarily on the same criteria applied to general industrial facilities, primarily those concerning life safety and property loss prevention. This practice continued until 1975 when the Brown's Ferry nuclear reactor site experienced a severe cable tray fire. The fire burned for over seven hours, due in part to the reluctance of on-site personnel to use water on the fire for fear of shorting out critical electrical circuits. 4 figs.

The radiation spectrum constituents of interest to microelectronics are prompt gamma or x-ray, total dose, neutrons (or protons), and cosmic radiation. Each of these constituents has a unique effect upon microelectronic components and requires unique techniques to improve the microelectronic radiation tolerance to such an exposure. This paper reviews the radiation effects associated with the natural space and nuclear reactor radiation environment, that is to say, total dose, neutrons, and cosmic rays. 2 refs., 6 figs.

Shock-induced reaction synthesis (SRS) is used for solid state processing of Ni-Al, Ni-Si, and Nb-Si type compounds, starting with elemental powder mixtures. The constituent elemental powders are blended in different stoichiometries and packed at 65% density in stainless steel capsules. A steel flyer plate, accelerated by the detonation of an explosive, impacts the powder containing capsules embedded in a steel recovery fixture backed by a momentum trap. The shock wave generated upon impact triggers a self-sustaining, exothermic reaction between the elemental powder constituents, thereby synthesizing the compound and at the same time consolidating the porous mass into 12mm diameter by 5mm thick compacts. The characteristics of the SRS technique and the structural features of the shock synthesized products will be discussed. 18 refs., 11 figs.

Preliminary BUCKSHOT simulations of a recirculating linear accelerator have been made. Two accelerator configurations have been examined for a variety of beam currents (10-40 kA). The first configuration is an attempt to simulate conditions accessible to near-term experiments. The second configuration tries to mock up a next generation application type machine. 3 figs.

Hypervelocity launchers are used to study the high-pressure equation of state of materials in regimes inaccessible by other methods. Two-stage light gas guns have been extremely useful for these applications, but have a practical velocity limit of about 8--9 km/s for impact studies. In this paper, we describe a three-stage launcher consisting of a two-stage light gas gun combined with a third-stage railgun, which overcomes previous velocity limitations pertaining to two-stage guns. This launcher is being developed for operation to 15 km/s and has achieved projectile velocities of 7.2 km/s to date. 10 refs., 9 figs., 1 tab.

The in-plane linear elastic constants of woven fabric are determined in terms of the specific fabric microstructure. The fabric is assumed to be a spatially periodic interlaced network of orthogonal yarns and the individual yarns are modeled as extensible elastica. These results indicate that a significant coupling of bending and stretching effects occurs during deformation. Results of this theoretical analysis compare favorable with measured in-plane elastic constants for Vincel yarn fabrics. 17 refs., 2 figs., 1 tab.

The utility of the magnetically insulated transmission line oscillator (MILO) as a high power microwave source depends on how efficiently power can be extracted from it. We have designed a slow-wave stepped transformer for the purpose of axially extracting microwave power from a 3.6 GHz coaxial MILO. The slow-wave transformer design was optimized using particle-in-cell simulation, and tested in experiments performed on the HPM Simulation Division's GEMINI and GYPSY water Blumlein pulse power sources. In this paper we summarize the slow-wave stepped transformer design, and describe MILO axial power extraction experiments which yielded up to 300 MW of radiated power. 10 refs., 4 figs., 2 tabs.

This presentation is a case study of the system that was developed to move data between our mainframe HRIS and the REGISTRAR. It not only contains a description of the system itself but of the factors that come into play in deciding whether to implement a system at all and in deciding what kind of system to implement.