Article discussing auditory cortex neurons and primary culture and ion channel activity in rat.

Article on the solubility of anthracene in ternary propanol + butanol + 2,2,4-trimethylpentane solvent mixtures.

We have explored the major technical and conceptual issues relating to the suitability of a diode-pumped solid state laser as a driver for an inertial fusion energy power plant. While solid state lasers have long served as the workhorse of inertial confinement fusion physics studies, the deployment of a driver possessing adequate efficiency, reliability, and repetition rate for inertial fusion energy requires the implementation of several technical innovations discussed in this article.

The Overture framework is an object-oriented environment for solving partial differential equations in two and three space dimensions. It is a collection of C++ libraries that enables the use of finite difference and finite volume methods at a level that hides the details of the associated data structures. Overture can be used to solve problems in complicated, moving geometries using the method of overlapping grids. It has support for grid generation, difference operators, boundary conditions, data-base access and graphics. Short sample code segments are presented to show the power of this approach.

Calculation of river flow is important for managing reservoirs and flood forecasting. In the western United States, a complex terrain which is characterized by steep slopes and narrow valleys often cause a substantial rise of river levels in a short period during heavy precipitation events. Since flood control is one of the major tasks of reservoir operation, inaccurate predictions of precipitation and river flow may cause flooding or waste of water resources. Accurate calculations of river flow need accurate liquid water input to the river system at scales of individual watersheds. Precipitation and snowmelt are the most important natural source of water for a river. Reservoir operations significantly affect river flow in the western United States. Factors such as instantaneous soil water content, vegetation cover, terrain slope and ground water table structure are also crucial for river flow calculation. There are two types of precipitation: rain and snowfall. River flow quickly responds to rainfall while snowfall does not directly affect river flow until it melts afterwards. Therefore, these two types of precipitation must be separately provided to the river flow model for correct calculation of river flows. A large portion of snowfall is accumulated at high terrain during winter months …

The influence of oxygenated hydrocarbons as additives to diesel fuels on ignition, NOx emissions and soot production has been examined using a detailed chemical kinetic reaction mechanism. N-heptane was used as a representative diesel fuel, and methanol, ethanol, dimethyl ether and dimethoxymethane were used as oxygenated fuel additives. It was found that addition of oxygenated hydrocarbons reduced NOx levels and reduced the production of soot precursors. When the overall oxygen content in the fuel reached approximately 25% by mass, production of soot precursors fell effectively to zero, in agreement with experimental studies. The kinetic factors responsible for these observations are discussed.

This paper theoretically compares the performance of simulated annealing and evolutionary algorithms. Our main result is that under mild conditions a wide variety of evolutionary algorithms can be shown to have greater performance than simulated annealing after a sufficiently large number of function evaluations. This class of EAs includes variants of evolutionary strategie and evolutionary programming, the canonical genetic algorithm, as well as a variety of genetic algorithms that have been applied to combinatorial optimization problems. The proof of this result is based on a performance analysis of a very general class of stochastic optimization algorithms, which has implications for the performance of a variety of other optimization algorithm.

Two bulkheads, one composed of high performance concrete and the other of highly compacted sand-bentonite material, have been constructed in a tunnel in unfractured granite rock at the Underground Research Laboratory. The Tunnel Sealing Experiment will characterize the performance of the two bulkheads under applied hydraulic pressures. The chamber between the two bulkheads will be pressurized to approximately 4 MPa, a value representative of the ambient pore pressures in the rock at a depth of 420 m. Instrumentation in the experiment monitors the seepage through and around each bulkhead as well as the changes tot he pure water pressure, and hence changes to the flow directions,in the intact rock. Stresses and displacements in each bulkhead are also monitored. The objective of the experiment is to demonstrate technologies for contrustion of bentonite and concrete bulkheads and to quantify the performance of each bulkhead.

IN THIS PAPER, RESULTS FROM IMPEDANCE MEASUREMENTS ON THE RHIC INJECTION KICKERS ARE REPORTED. THE KICKER IS CONFIGURED AS A ''C'' CROSS SECTION MAGNET WITH INTERLEAVED FERRITE AND HIGH-PERMITTIVITY DIELECTRIC SECTIONS TO ACHIEVE A TRAVELLING WAVE STRUCTURE. THE IMPEDANCE WAS MEASURED USING THE WIRE METHOD, AND ACCURATE RESULTS ARE OBTAINED BY INTERPRETING THE FORWARD SCATTERING COEFFICIENT VIA THE LONG-FORMULA. THE FOUR KICKERS WITH THEIR CERAMIC BEAM TUBES CONTRIBUE AT Z/N-0.22 OMEGA/RING IN THE INTERESTING FREQUENCY RANGE FROM 0.1 TO 1 BHZ, AND LESS ABOVE.

Two irradiation test vehicles, designated RERTR-1 and RERTR-2, were inserted into the Advanced Test Reactor in Idaho in August 1997. These tests were designed to obtain irradiation performance information on a variety of potential new, high-density uranium alloy dispersion fuels, including U-10Mo,U-8Mo, U-6Mo, U-4Mo, U-9Nb-3Zr, U-6Nb-4Zr, U-5Nb-3Zr, U-6Mo-1Pt, U-6Mo-0.6Ru and U-10Mo-0.05Sn; the intermetallic compounds U{sub 2}Mo and U{sub 3}Si{sub 2} were also included in the fuel test matrix. These fuels are included in the experiments as ''microplates'' (76 mm x 22 mm x 1.3 mm outer dimensions) with a nominal fuel volume loading of 25% and irradiated at relatively low temperature ({approximately} 100 C). RERTR-1 and RERTR-2 were discharged from the reactor in November 1997 and July 1998, respectively, at calculated peak fuel burnups of 45 and 71 at.%-U{sup 235}. Both experiments are currently under examination at the Alpha Gamma Hot Cell Facility at Argonne National Laboratory in Chicago. This paper presents the postirradiation examination results available to date from these experiments.

Simple tangent, hard site chains near a hard wall are modeled with a Density Functional (DF) theory that uses the direct correlation function, c(r), as its ''input''. Two aspects of this DF theory are focused upon: (1) the consequences of variations in c(r)'s detailed form; and (2) the correct way to introduce c(r) into the DF formalism. The most important aspect of c(r) is found to be its integrated value, {cflx c}(0). Indeed, it appears that, for fixed {cflx c}(0), all reasonable guesses of the detailed shape of c(r) result in surprisingly similar density distributions, {rho}(r). Of course, the more accurate the c(r), the better the {rho}(r). As long as the length scale introduced by c(r) is roughly the hard site diameter and as long as the solution remains liquid-like, the {rho}(r) is found to be in good agreement with simulation results. The c(r) is used in DF theory to calculate the medium-induced-potential, U{sub M}(r) from the density distribution, {rho}(r). The form of U{sub M}(r) can be chosen to be one of a number of different forms. It is found that the forms for U{sub M}(r), which yield the most accurate results for the wall problem, are also those which …

The Experimental Breeder Reactor-II (EBR-II) at Argonne National Laboratory-West (ANL-W) was shutdown in September, 1994. This sodium cooled reactor had been in service since 1964, and by the US Department of Energy (DOE) mandate, was to be placed in an industrially and radiologically safe condition for ultimate decommissioning. The deactivation of a liquid metal reactor presents unique concerns. The first major task associated with the project was the removal of all fueled assemblies. In addition, sodium must be drained from systems and processed for ultimate disposal. Residual quantities of sodium remaining in systems must be deactivated or inerted to preclude future hazards associated with pyrophoricity and generation of potentially explosive hydrogen gas. A Sodium Process Facility (SPF) was designed and constructed to react the elemental sodium from the EBR-II primary and secondary systems to sodium hydroxide for disposal. This facility has a design capacity to allow the reaction of the complete inventory of sodium at ANL-W in less than two years. Additional quantities of sodium from the Fermi-1 reactor are also being treated at the SPF.

The use of principal component (factor) analysis in the analysis EXAFS spectra is described. The components derived from EXAFS spectra share mathematical properties with the original spectra. As a result, the abstract components can be analyzed using standard EXAFS methodology to yield the bond distances and other coordination parameters. The number of components that must be analyzed is usually less than the number of original spectra. The method is demonstrated using a series of spectra from aqueous solutions of uranyl ions.

The irradiation, disassembly, and processing of two full-scale low-enriched uranium (LEU) targets were recently demonstrated by personnel in the BATAN PUSPIPTEK Facilities (Serpong, Indonesia). Targets were fabricated at Argonne National Laboratory (Argonne, IL, U.S.A.) and shipped to PUSPIPTEK. The processing was done by nearly the same procedure used for the production of {sup 99}Mo from high-enriched uranium (HEU) targets. The BATAN Radioisotope Production Centre produces {sup 99}Mo using the Cintichem process by first dissolving the uranium in an acid cocktail; three proprietary separation steps recover the {sup 99}Mo and purify it from other components of the irradiated uranium. Processing of LEU-metal targets is nearly identical to that used for HEU-oxide targets except (1) a separate dissolver is required and (2) the dissolution cocktail is nitric acid alone rather than a nitric/sulfuric acid mixture. The demonstrations went smoothly except for problems with sampling and gamma analysis to assess product purity. Foils could be removed from targets fabricated from zirconium and/or 304 stainless steel, and processing produced an equivalent yield of {sup 99}Mo/{sup 235}U to that of the HEU target.

Vibrational spectroscopic and electrochemical techniques are among the most useful tools for the elucidation of corrosion-passivation phenomena in metals. The former can provide information on the structure and composition of corrosion films ''in situ'' in aqueous solution environments, while thermodynamic and kinetic information may be obtained using electrochemical techniques. In this paper, we demonstrate the application of Laser Raman Scattering (LRS) and Synchrotrons Far Infrared Reflectance Spectroscopy (SFIRS), coupled with electrochemical methods, for the determination of the structure and composition of surface films on nickel and copper in aqueous solution environment. The corrosion film on nickel has been found to consist of NiO and Ni(OH){sub 2} in the passive region of potential and NiOOH in the transpassive region. The film on copper consists of Cu{sub 2}O, CUO and Cu(OH){sub 2}. We also show for the first time that SFIRS can be used to obtain information on the adsorption of ions on a metal surface with sub-monolayer sensitivity. Adsorption of Cl{sup {minus}}, Br{sup {minus}}, SO{sup {minus}2}, and PO{sub 4}{sup {minus}3} was found to occur at gold electrodes in perchloric acid solution. We also observed that when two different ions are present in solution, the more strongly adsorbed ion determined the corrosion …

In the Mathematics and Computer Science Division at Argonne, the demand for resources on the Onyx 2 exceeds the resources available for consumption. To distribute these scarce resources effectively, we need a scheduling and resource management package with multiple capabilities. In particular, it must accept standard interactive user logins, allow batch jobs, backfill the system based on available resources, and permit system activities such as accounting to proceed without interruption. The package must include a mechanism to treat the graphic pipes as a schedulable resource. Also required is the ability to create advance reservations, offer dedicated system modes for large resource runs and benchmarking, and track the resources consumed for each job run. Furthermore, our users want to be able to obtain repeatable timing results on job runs. And, of course, package costs must be carefully considered. We explored several options, including NQE and various third-party products, before settling on the PBS scheduler.

An in vivo study of vascular welding with a fiber-delivered argon laser was conducted using a canine model. Longitudinal arteriotomies and venotomies were treated on femoral vein and artery. Laser energy was delivered to the vessel wall via a 400 {micro}m optical fiber. The surface temperature at the center of the laser spot was monitored in real time using a hollow glass optical fiber-based two-color infrared thermometer. The surface temperature was limited by either a room-temperature saline drip or direct feedback control of the laser using a mechanical shutter to alternately pass and block the laser. Acute patency was evaluated either visually (leak/no leak) or by in vivo burst pressure measurements. Biochemical assays were performed to investigate the possible laser-induced formation or destruction of enzymatically mediated covalent crosslinks between collagen molecules. Viable welds were created both with and without the use of feedback control. Tissues maintained at 50 C using feedback control had an elevated crosslink count compared to controls, while those irradiated without feedback control experienced a decrease. Differences between the volumetric heating associated with open and closed loop protocols may account for the different effects on collagen crosslinks. Covalent mechanisms may play a role in argon laser vascular …

PDS/PIO is a lightweight, parallel interface designed to support efficient transfers of massive, grid-based, simulation data among memory, disk, and tape subsystems. The higher-level PDS (Parallel Data Set) interface manages data with tensor and unstructured grid abstractions, while the lower-level PIO (Parallel Input/Output) interface accesses data arrays with arbitrary permutation, and provides communication and collective 1/0 operations. Higher-level data abstraction for finite element applications is provided by PXI (Parallel Exodus Interface), which supports, in parallel, functionality of Exodus 11, a finite element data model developed at Sandia National Laboratories. The entire interface is implemented in C with Fortran-callable PDS and PXI wrappers.

During 1998, the emphasis of our activities was focused mainly on target fabrication. Successful conversion requires a reliable irradiation target; the target being developed uses thin foils of uranium metal, which can be removed from the target hardware for dissolution and processing. This paper describes successes in (1) improving our method for heat-treating the uranium foil to produce a random-small grain structure, (2) improving electrodeposition of zinc and nickel fission-fragment barriers onto the foil, and (3) showing that these fission fragment barriers should be stable during transport of the targets following irradiation. A method was also developed for quantitatively electrodepositing uranium and plutonium contaminants in the {sup 99}Mo. Progress was also made in broadening international cooperation in our development activities.

Laboratory measurements of the electrical resistivity of rocks and synthetic rocks with confining pressures up to 100 bars and temperatures between 20 and 211 C were performed to further investigate how the pore-size distribution and capillarity affects boiling in porous media. Similar to previous measurements on samples from The Geysers, CA, we observed a gradual increase in resistivity when pore pressure was decreased below the phase-boundary pressure of free water, an indication that boiling is controlled not only by temperature and pressure, but also by pore size distribution. Other important phenomena observed were strong resistance fluctuations during boiling that may be chaotic, and salt deposition that caused sample cracking. If confirmed in further experiments, these results may lead to a new geophysical diagnostic for locating boiling in high permeability areas of geothermal reservoirs and for methods of permeability alteration.

In our application, dichroics in a high average power, near-infrared, laser system have short operating lifetimes. These dichroics were used as the resonator fold mirrors and permitted the transmission of the pumping argon (Ar) ion laser light. Representative samples of two different dichroic optics were taken off-line and the transmission performance monitored in various scenarios. Irradiating these optics under resonator vacuum conditions, ({le}1 mT, 11.7 kW/cm{sup 2}, Ar laser running all wavelengths) resulted in a degradation of transmission with time. Irradiating these optics in a rarefied oxygen atmosphere (1 to 10 T of oxygen, 11.7 kW/cm{sup 2}, Ar laser running all wavelengths) the transmission remained steady over a period of days. The transmission loss observed in the optic tested in vacuum was somewhat reversible if the optic was subsequently irradiated in a rarefied oxygen atmosphere. This reversibility was only possible if the transmission degradation was not too severe. Further tests demonstrated that an atmosphere of 10 T of air also prevented the transmission degradation. In addition, tests were performed to demonstrate that the optic damage was not caused by the ultra-violet component in the Ar ion laser. Mechanisms that may account for this behavior are proposed.

An effective two-body nuclear interaction is presented which is a sum of terms separable in coordinate space. Calculations are made using this interaction of some doubly closed-shell spherical nuclei using many-body perturbation theory with the Hartree-Fock state as a reference state. It is demonstrated that the interaction gives good bulk properties in finite nuclei.

Radioactive and hazardous wastes are generated at many national laboratories, military sites, fuel fabrication and enrichment plants, reactors, and many other facilities. At all of these sites, wastes must be separated, categorized, possibly treated, and packed into containers for shipment to waste-storage or disposal sites. Prior to treatment, storage or, shipment, the containers must be characterized to determine the ultimate disposition of the contained waste. Comprehensive and accurate nondestructive evaluation (NDE) and nondestructive assay (NDA) methods can be used to characterize most waste containers in a safe and cost-effective manner without opening them. The Lawrence Livermore National Laboratory (LLNL) is investigating and developing the application of x-ray and {gamma}-ray methods to nonintrusively characterize waste containers and/or items. X-ray NDE methods are being investigated to determine whether they can be used to identify hazardous and nonconforming materials. A {gamma}-ray NDA method is used to identify the radioactive sources within a container and to accurately quantify their strength. In this paper we describe five waste characterization projects being conducted at LLNL that apply both the NDE and NDA methods and present results.

We present a robust, model-independent technique for measuring changes in the dynamics underlying nonlinear time-serial data. We define indicators of dynamical change by comparing distribution functions on the attractor via L{sub 1}-distance and X{sup 2} statistics. We apply the measures to scalp EEG data with the objective of capturing the transition between non-seizure and epileptic brain activity in a timely, accurate, and non-invasive manner. We find a clear superiority of the new metrics in comparison to traditional nonlinear measures as discriminators of dynamical change.