We report results on the use of neural nets, and the closely related radial basis nets'', to analyze experimental time series from electro-chemical systems. We show how the nets may be used to derive a map that describes the nonlinear system, and how reserving an extra input line'' of the network allows one to learn the system behavior dependent on a control variable. Pruning'' of the network after training appears to result in elimination of spurious connection weights and enhanced predictive accuracy. Subsequent analysis of the learned map using techniques of bifurcation theory allows both nonlinear system identification and accurate and efficient predictions of long-term system behavior. The electrochemical system that was used involved the electrodissolution of copper in phosphoric acid. This system exhibits interesting low dimensional dynamics such transitions from steady state to oscillatory behavior and from period-one to period-two oscillations. This analysis provides an example of methodology that can be fruitful in understanding systems for which no adequate phenomenological model exists, or for which predictions of system behavior given a large scale, complicated model is inherently impractical. 17 refs., 2 figs.

A high level of current dependent bunch lengthening has been observed on the North damping ring of the Stanford Linear Collider (SLC). At currents of 3 {times} 10{sup 10} this behavior does not appear to degrade the machine's performance significantly. However, at the higher currents that are envisioned for the future one fears that its performance could be greatly degraded due to the phenomenon of bunch lengthening. This was the motivation for the work described in this paper. In this paper we calculate the longitudinal impedance of the damping ring vacuum chamber. More specifically, in this paper we find the response function of the ring to a short Gaussian bunch, which we call the Green function wake. In addition, we try to estimate the relative importance of the different vacuum chamber objects, in order to see how we might reduce the ring impedance. This paper also describes bunch length measurements performed on the North damping ring. We use the Green function wake, discussed above, to compute the bunch lengthening. Then we compare these results with those obtained from the measurements. In addition, we calculate the current dependence of the tune distribution.

The CDF detector has collected data for an integrated luminosity of 4.4 pb{sup {minus}1} during the 1988--89 Tevatron Collider run. This sample has been used to search for the top quark. We report here the results of the analysis of the electron-muon topology. We find that a top mass in the 28 to 72 GeV is excluded at the 95% confidence level. The same limits apply to a possible fourth generation, charge {minus}1/3, b{prime} quark decaying via the charged current. 21 refs., 14 figs.

The charge of this group was to evaluate the physics that can be done with a high luminosity {mu} scattering experiment at FNAL using the upgraded Tevatron muon beam, and consider the apparatus required. In this report, the physics that can be accomplished with a high luminosity {mu} scattering experiment is evaluated. The CERN and FNAL {mu} beams are compared in the context of such an experiment. The expected muon flux with the upgraded machine is estimated. Two possible detectors are compared: the air-core toroid experiment proposed by Guyot et al., and an upgraded version of the E665 double-diode apparatus now in place at FNAL. The relative costs of the detectors are considered. A list of detailed questions that need to be answered regarding the double-diode experiment has be compiled. 2 refs., 10 figs., 2 tabs.

This paper presents preliminary transport calculations for radionuclide movement at Yucca Mountain. Several different realizations of spatially distributed sorption coefficients are used to study the sensitivity of radionuclide migration. These sorption coefficients are assumed to be functions of the mineralogic assemblages of the underlying rock. The simulations were run with TRACRN{sup 1}, a finite-difference porous flow and radionuclide transport code developed for the Yucca Mountain Project. Approximately 30,000 nodes are used to represent the unsaturated and saturated zones underlying the repository in three dimensions. Transport calculations for a representative radionuclide cation, {sup 135}Cs, and anion, {sup 99}Tc, are presented. Calculations such as these will be used to study the effectiveness of the site`s geochemical barriers at a mechanistic level and to help guide the geochemical site characterization program. The preliminary calculations should be viewed as a demonstration of the modeling methodology rather than as a study of the effectiveness of the geochemical barriers. The model provides a method for examining the integration of flow scenarios with transport and retardation processes as currently understood for the site. The effects on transport of many of the processes thought to be active at Yucca Mountain may be examined using this approach. 11 refs., …

Risk Management is the optimization of safety programs. This requires a formal systems approach to hazards identification, risk quantification, and resource allocation/risk acceptance as opposed to case-by-case decisions. The Management Oversight and Risk Tree (MORT) has gained wide acceptance as a comprehensive formal systems approach covering all aspects of risk management. It (MORT) is a comprehensive analytical procedure that provides a disciplined method for determining the causes and contributing factors of major accidents. Alternatively, it serves as a tool to evaluate the quality of an existing safety system. While similar in many respects to fault tree analysis, MORT is more generalized and presents over 1500 specific elements of an ideal ''universal'' management program for optimizing occupational safety.

The possibilities for future physics and experiments involving weak and electromagnetic interactions, neutrino oscillations, general hard scattering and experiments involving nuclear targets were explored. The studies were limited to the physics accessible using fixed target experimentation. While some of the avenues explored turn out to be relatively unrewarding in the light of competition elsewhere in the world, there are a number of positive conclusions reached about experimentation in the energy range available to the Main Injector and Tevatron. Some of the experiments would benefit from the increased intensity available from the Tevatron utilizing the Main Injector, while some require this increase. Finally, some of the experiments would use the Main Injector low energy, high intensity extracted beams directly. A program of electroweak and hard scattering experiments at fixed target energies retains the potential for important contributions to physics. The key to major parts of this program would appear to be the existence of the Main Injector. 115 refs, 17 figs.

In this paper we review the progress of the shell-model approach to understanding the properties of light exotic nuclei (A < 40). By shell-model'' we mean the consistent and large-scale application of the classic methods discussed, for example, in the book of de-Shalit and Talmi. Modern calculations incorporate as many of the important configurations as possible and make use of realistic effective interactions for the valence nucleons. Properties such as the nuclear densities depend on the mean-field potential, which is usually separately from the valence interaction. We will discuss results for radii which are based on a standard Hartree-Fock approach with Skyrme-type interactions.

We have designed and built a high-temperature, plasma-assisted, chemical vapor deposition system to deposit multilayer optical coatings of SiO{sub 2} and doped-SiO{sub 2} flat substrates. The coater concept and design is an outgrowth of our recent work with Schott Glasswerke demonstrating the use of plasma assisted CVD to prepare very high damage threshold optical coatings. The coater is designed to deposit up to several thousand alternating quarterwave layers of SiO{sub 2} and doped SiO{sub 2} substrate at deposition rates up to several microns per minute. The substrate is resistively heated to about 1000{degree}C during the deposition phase of the process. The plasma is driven by a 13.56 MHz RF unit capable of producing power densities of up to 140 W cm{sup {minus}3} in the reaction zone. The coater is designed to be adaptable to microwave generated plasmas, as well as RF. Reactant gas flow rates of up to 10 slm can be achieved at a 10 tar operating pressure. Reactants consist of O{sub 2}, SiCl{sub 4} and a volatile halogenated dopant. These gases react in the plasma volume producing SiO{sub 2} with dopant concentrations of up to a few percent. A variable dopant concentration is used to produce index differences …

This presentation is intended to familiarize non-platers with electrolytic and electroless deposition techniques and how these methods are used to manufacture non-reinforced metal parts by the electroforming process. The techniques enable manufacture of complex shapes, often at lower cost than other forming methods. Electroless techniques are deposition methods which provide uniform deposits of very low porosity without the use of electrical current. In electroforming, the part is formed by deposition on a mandrel or preform, from which it is subsequently separated. 10 refs., 1 fig.

Nickel-Phosphorus alloys are attractive materials for diamond turning applications such as fabrication of large optics and other high precision parts. Although the mechanism is not understood, diamond tool wear is minimized when the phosphorus content of the deposit is greater than 11% (wgt). In recent years, increased attention has been directed at electrodeposition as an alternate to electroless deposition for producing Ni-P alloys. One principal advantage of the electrodeposition process is that alloys with 14--15% P can be obtained; another is that an order of magnitude greater deposition thickness can be provided if necessary. This paper compares diamond turning results for electrodeposited and electroless Ni-P alloys and shows that the electrodeposited coatings provide promising results. 28 refs., 7 figs., 1 tab.

The physics of hadron colliders is briefly reviewed. Issues for further study are presented. Particular attention is given to the physics opportunities for a high luminosity ({ge} 100 pb{sup {minus}1}/experiment/run) Upgrade of the Tevatron Collider. 25 refs., 10 figs., 2 tabs.

The need for the next generation electron-positron collider is discussed within the context of the Standard Model and the physics that must lie beyond it.

The initial motivation for this work was the reported discovery in January 1989 of a 1/2 millisecond pulsar in the remnant of the spectacular supernova, 1987A. The status of this discovery has come into grave doubt as of data taken by the same group in February, 1990. At this time we must consider that the millisecond signal does not belong to the pulsar. The existence of a neutron star in remnant of the supernova is suspected because of recent observations on the light curve of the remnant, and of course by the neutrino burst that announced the supernova. However its frequency is unknown. I can make a strong case that a pulsar rotation period of about 1 ms divides those that can be understood quite comfortably as neutron stars, and those that cannot. What we will soon learn is whether there is an invisible boundary below which pulsar periods do not fall, in which case, all are presumable neutron stars, or whether there exist sub- millisecond pulsars, which almost certainly cannot be neutron stars. Their most plausible structure is that of a self-bound star, a strange-quark-matter star. The existence of such stars would imply that the ground state of the …

Characterizing Fast Flux Test Facility (FFTF) core restraint system performance has been ongoing since the first operating cycle. Characterization consists of prerun analysis for each core load, in-reactor and postirradiation measurements of subassembly withdrawal loads and deformations, and using measurement data to fine tune predictive models. Monitoring FFTF operations and performing trend analysis has made it possible to gain insight into core restraint system performance and head off refueling difficulties while maximizing component lifetimes. Additionally, valuable information for improved designs and operating methods has been obtained. Focus is on past operating experience, emphasizing performance improvements and avoidance of potential problems. 4 refs., 12 figs., 2 tabs.

A monolithically integrated detector-preamplifier on high-resistivity silicon has been designed, fabricated and characterized. The detector is a fully depleted p-i-n diode and the preamplifier is implemented in a depletion-mode PMOS process which is compatible with detector processing. The amplifier is internally compensated and the measured gain-bandwidth product is 30 MHz with an input-referred noise of 15 nV/{radical}Hz in the white noise regime. Measurements with an Am{sup 241} radiation source yield an equivalent input noise charge of 800 electrons at 200 ns shaping time for a 1.4 mm{sup 2} detector with on-chip amplifier in an experimental setup with substantial external pickup.

Drift chambers are one of the position sensing technologies used in cosmic ray balloon and satellite experiments with potential application to the next generation of detectors for space flight. A low mass TPC type drift chamber, employing 8 distinct drift regions within a single gas volume has been built, tested and used at the LBL Bevalac. From the drift time X-coordinate, spatial resolutions below 100 {mu}m are obtained for a variety of heavy ions with selected trigger modes. The Y-coordinate is determined by pickup pads located behind the anode wire, thereby providing both X and Y coordinates from the same avalanche. Results from different timing schemes, {delta}-ray effects and the pickup pad resolution are presented. 6 refs., 5 figs.

The US Department of Energy, through its Yucca Mountain Project Office, has been conducting prototype activities in welded and non-welded tuff. These activities are in preparation for characterization of the Yucca Mountain area, which is under consideration as a site for a geologic repository in which high-level nuclear waste could be safely stored. Investigators from organizations that will conduct the site investigation have been afforded opportunity, through the prototype program, to test, evaluate, and develop instruments, equipment, and methods. The Exploratory Shaft Facility will be used to collect significant amounts of underground site characterization data. The prototype tests are conducted under similar conditions. 3 refs., 4 figs.

A brief description of the Exploratory Shaft based site characterization testing program for the Yucca Mountain Project of the permanent disposal of high level radioactive waste is briefly described in this paper. Details of the testing program are presented in the DOE-issued Site Characterization Plan. Overview of the current planning process and status of various activities is briefly described. This study will reevaluate the mining method, ESF location and any changes in the ESF testing program. 2 refs., 2 figs., 1 tab.

To implement an efficient data-parallel program on a non-shared memory MIMD multicomputer, data and computations must be properly partitioned to achieve good load balance and locality of reference. Programs with irregular data reference patterns often require irregular partitions. Although good partitions may be easy to determine, they can be difficult or impossible to implement in programming languages that provide only regular data distributions, such as blocked or cyclic arrays. We are developing Onyx, a programming system that provides a shared memory model of distributed data structures and extends the concept of data distribution to include irregular and dynamic distributions. This provides a powerful means to specify irregular partitions. Perhaps surprisingly, programs using it can also execute efficiently. In this paper, we describe and evaluate the Onyx implementation of a model problem that repeatedly executes an irregular but fixed data reference pattern. On an NCUBE hypercube, the speed of the Onyx implementation is comparable to that of carefully handwritten message-passing code.

The development of implicit methods of particle-in-cell (PIC) computer simulation in recent years, and their merger with older hybrid methods have created a new arsenal of simulation techniques for the treatment of complex practical problems in plasma physics. The new implicit hybrid codes are aimed at transitional problems that lie somewhere between the long time scale, high density regime associated with MHD modeling, and the short time scale, low density regime appropriate to PIC particle-in-cell techniques. This transitional regime arises in ICF coronal plasmas, in pulsed power plasma switches, in Z-pinches, and in foil implosions. Here, we outline how such a merger of implicit and hybrid methods has been carried out, specifically in the ANTHEM computer code, and demonstrate the utility of implicit hybrid simulation in applications. 25 refs., 5 figs.

At the Solar Energy Research Institute (SERI), we carried out tests to measure the effects of leading-edge roughness on an S809 airfoil using a 10-m, three-bladed, horizontal-axis wind turbine (HAWT). The rotor employed a constant-chord (.457 m) blade geometry with zero twist. Blade structural loads were measured with strain gages mounted at 9 spanwise locations. Airfoil pressure measurements were taken at the 80% spanwise station using 32 pressure taps distributed around the airfoil surface. Detailed inflow measurements were taken using nine R.M. Young Model 8002 propvane anemometers on a vertical plane array (VPA) located 10 m upwind of the test turbine in the prevailing wind direction. The major objective of this test was to determine the sensitivity of the S809 airfoil to roughness on a rotating wind turbine blade. We examined this effect by comparing several parameters. We compared power curves to show the sensitivity of whole rotor performance to roughness. We used pressure measurements to generate pressure distributions at the 80% span which operates at a Reynolds number (Re) of 800,000. We then integrated these distributions to determine the effect of roughness on the section&#x27;s lift and pressure-drag coefficients. We also used the shapes of these distributions to understand …

This paper discusses the relationship between surface energy and compressibility as they relate to the nucleus. 5 refs., 4 figs. (LSP)

In this paper we present an overview of the EGS4 Code System -- a general purpose package for the Monte Carlo simulation of the transport of electrons and photons. During the last 10-15 years EGS has been widely used to design accelerators and detectors for high-energy physics. More recently the code has been found to be of tremendous use in medical radiation physics and dosimetry. The problem-solving capabilities of EGS4 will be demonstrated by means of a variety of practical examples. To facilitate this review, we will take advantage of a new add-on package, called SHOWGRAF, to display particle trajectories in complicated geometries. These are shown as 2-D laser pictures in the written paper and as photographic slides of a 3-D high-resolution color monitor during the oral presentation. 11 refs., 15 figs.