Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to BTEX (benzene, toluene, ethylbenzene, and xylenes) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. MtBE was not degraded within 100 days under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds, and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which …

The performance of object-oriented applications often suffers from the inefficient use of high-level abstractions provided by underlying libraries. Since these library abstractions are user-defined and not part of the programming language itself only limited information on their high-level semantics can be leveraged through program analysis by the compiler and thus most often no appropriate high-level optimizations are performed. In this paper we outline an approach based on source-to-source transformation to allow users to define optimizations which are not performed by the compiler they use. These techniques are intended to be as easy and intuitive as possible for potential users; i.e. for designers of object-oriented libraries, people most often only with basic compiler expertise.

A source evaluation case study is presented for observations of algae toxicity in an intermittent stream passing through the Lawrence Livermore National Laboratory near Livermore, California. A five-step procedure is discussed to determine the cause of water toxicity problems and to determine appropriate environmental management practices. Using this approach, an upstream electrical transfer station was identified as the probable source of herbicides causing the toxicity. In addition, an analytical solution for solute transport in overland flow was used to estimate the application level of 40 Kg/ha. Finally, this source investigation demonstrates that pesticides can impact stream water quality regardless of application within levels suggested on manufacturer labels. Environmental managers need to ensure that pesticides that could harm aquatic organisms (including algae) not be used within close proximity to streams or storm drainages and that application timing should be considered for environmental protection.

Based on annual tritium release rates from the five sources of tritium at Lawrence Livermore National Laboratory and the Tritium Research Laboratory at Sandia National Laboratory, the regulatory dispersion and dose model, CAP88-PC, was used to predict tritium concentrations in air at perimeter and offsite air surveillance monitoring locations for 1986 through 2001. These predictions were compared with mean annual measured concentrations, based on biweekly sampling. Deterministic predictions were compared with deterministic observations using predicted-to-observed ratios. In addition, the uncertainty on observations and predictions was assessed: when the uncertainty bounds of the observations overlapped with the uncertainty bounds of the predictions, the predictions were assumed to agree with the observations with high probability. Deterministically, 54% of all predictions were higher than the observations, and 96% fell within a factor of three. Accounting for uncertainty, 75% of all predictions agreed with the observations; 87% of the predictions either matched or exceeded the observations. Predictions equaled or exceeded observations at those sampling locations towards which the wind blows most frequently, except those in the hills. Under-predictions were seen at locations towards which the wind blows infrequently when released tritium was from elevated sources. When a high fraction of tritium was from area …

We review the attempts to construct black hole/string solutions in asymptotically plane wave spacetimes. First, we demonstrate that geometries admitting a covariantly constant null Killing vector cannot admit event horizons, which implies that pp-waves can't describe black holes. However, relaxing the symmetry requirements allows us to generate solutions which do possess regular event horizons while retaining the requisite asymptotic properties. In particular, we present two solution generating techniques and use them to construct asymptotically plane wave black string/brane geometries.

We review the current status of flavor-changing neutral currents in the charm sector. We focus on the standard-model predictions and identify the main sources of theoretical uncertainties in both charm mixing and rare charm decays. The potential of these observables for constraining short-distance physics in the standard model and its extensions is compromised by the presence of large nonperturbative effects. We examine the possible discovery windows in which short-distance physics can be tested and study the effects of various extensions of the standard model. The current experimental situation and future prospects are reviewed.

None

None

None

None

Results on physics at RHIC using outgoing leptons and photons will be presented from Au+Au collisions at nucleon-nucleon c.m. energies {radical}(sNN) = 130 GeV and 200 GeV, and from p-p collisions at {radical}(sNN) = 200 GeV. Introduction and motivation will be presented both from the theoretical and experimental perspectives. Topics include open charm production via single e{sup {+-}}, J/{Psi} {yields} e{sup +} + e{sup -}, {mu}{sup +} + {mu}{sup -} and inclusive photon production.

Wiggler insertions are expected to occupy a significant portion of the lattice of the Next Linear Collider (NLC) Main Damping Rings (MDR) and have a noticeable impact on the single-particle beam dynamics. Starting from a realistic 3D representation of the magnetic fields we calculate the transfer maps for the wigglers, accounting for linear and nonlinear effects, and we study the beam dynamics with particular attention paid to the Dynamic Aperture(DA). A DA reduction is observed but appears to remain within acceptable limits.

Sloan Digital Sky Survey data for the field of the cluster Pal 5 reveal the existence of a long massive stream of tidal debris spanning an arc of 10{sup o} on the sky. Pal 5 thus provides an outstanding example for tidal disruption of globular clusters in the Milky Way. Radial velocities from VLT spectra show that Pal 5 has an extremely low velocity dispersion, in accordance with the very low mass derived from its total luminosity.

Among hazardous materials those which are most dangerous fall into three categories: chemical, biological, and radioactive. The DOT hazard classes for these three categories are Hazard Class 2.3 (poisonous gases) and 6.1 (toxic substances) for chemical hazards, Hazard Class 6.2 (infectious substances) for biological hazards and Hazard Class 7 for radioactive material (RAM) hazards. The packaging requirements for chemical and biological hazards are outlined and compared with RAM packaging requirements. RAM packages are found to be able to withstand much more severe performance tests than packages for other, more lethal hazards.

The heavy waters of the reactor effluent streams within the Savannah River Plant area transport very low concentrations of fission and activation products through miles of natural streambeds and swamps to the Savannah River. This study emphasizes the effects of environmental factors on the sorption of radionuclides by representative species.

Prevalent authentication and authorization models for distributed systems provide for the protection of computer systems and resources from unauthorized use. The rules and policies that drive the access decisions in such systems are typically configured up front and require trust establishment before the systems can be used. This approach does not work well for computer software that moderates human-to-human interaction. This work proposes a new model for trust establishment and management in computer systems supporting collaborative work. The model supports the dynamic addition of new users to a collaboration with very little initial trust placed into their identity and supports the incremental building of trust relationships through endorsements from established collaborators. It also recognizes the strength of a users authentication when making trust decisions. By mimicking the way humans build trust naturally the model can support a wide variety of usage scenarios. Its particular strength lies in the support for ad-hoc and dynamic collaborations and the ubiquitous access to a Computer Supported Collaboration Workspace (CSCW) system from locations with varying levels of trust and security.

Fermilab, in collaboration with the DESY laboratory in Hamburg, Germany, has created a petabyte scale data storage infrastructure to meet the requirements of experiments to store and access large data sets. The Fermilab data storage infrastructure consists of the following major storage and data transfer components: Enstore mass storage system, DCache distributed data cache, ftp and Grid ftp for primarily external data transfers. This infrastructure provides a data throughput sufficient for transferring data from experiments' data acquisition systems. It also allows access to data in the Grid framework.

Run II at the Tevatron Collider started at the beginning of March 2001. With extensive upgrades on both detectors and electronics the CDF II began to collect data. This paper reviews early Run II physics results obtained by analyzing data collected before the middle of June 2002. At the present the understanding of the detector performances is rather high so many analysis are already underway.

Equations by Marshall and by Millington and Quirk for calculating hydraulic conductivity from pore-size distribution data are dependent on an arbitrary choice of the exponent on the porosity term and a correct estimate of residual water. This study showed that a revised equation, based on the pore-interaction model of Marshall, accurately predicts hydraulic conductivity for glass beads and a loam soil from the pressure-water content relationships of these porous materials.

This conference paper considers how to use reaction path diagrams to better understand the output of reacting flow simulations. Briefly, these diagrams have long been used to depict the reactants and products in networks of chemical reactions. The diagrams can be generated in several ways from computer simulations of chemically reacting fluids to depict how the fluid moderates the chemistry by determining which species are brought into contact to react in quantity. The concept of a conditional diagram is introduced which depicts the reactions occurring in only a portion of the fluid domain, thus enabling comparisons between different regions of the fluid and the overall reaction network. Several examples are provided of the paths occurring in methane diffusion flames.

Measurements of magnetic susceptibility {chi}(T), specific heat C(T), Hall coefficient R{sub H}(T), and Yb valence {nu} = 2 + n{sub f} [f-occupation number n{sub f} (T) determined from Yb L{sub 3} x-ray absorption measurements] were carried out on single crystals of Yb{sub 1-x}Lu{sub x}Al{sub 3}. The low temperature anomalies observed in {chi}(T) and C(T) corresponding to an energy scale T{sub coh} {approx} 40 K in the intermediate valence, Kondo lattice compound YbAl{sub 3} are suppressed by Lu concentrations as small as 5% suggesting these low-T anomalies are extremely sensitive to disorder and, therefore, are a true coherence effect. By comparing the temperature dependence of various physical quantities to the predictions of the Anderson Impurity Model, the slow crossover behavior observed in YbAl{sub 3}, in which the data evolve from a low-temperature coherent, Fermi-liquid regime to a high temperature local moment regime more gradually than predicted by the Anderson Impurity Model, appears to evolve to fast crossover behavior at x {approx} 0.7 where the evolution is more rapid than predicted. These two phenomena found in Yb{sub 1-x}Lu{sub x}Al{sub 3}, i.e., the low-T anomalies and the slow/fast crossover behavior are discussed in relation to recent theories of the Anderson lattice.

Radon gas concentrations have been monitored as part of the operation of a tunnel (the Exploratory Studies Facility-ESF) at Yucca Mountain to ensure worker safety. The objective of this study was to examine the potential use of the radon data to estimate large-scale formation properties of fractured tuffs. This objective was examined by developing a numerical model, based upon the characteristics of the ESF and the Topopah Spring welded (TSw) tuff unit, capable of predicting radon concentrations for prescribed ventilation conditions. The model was used to address two specific issues. First, it was used to estimate the permeability and porosity of the fractures in the TSw at the length scale of the ESF and extending tens of meters into the TSw, which surrounds the ESF. Second, the model was used to understand the mechanism leading to radon concentrations exceeding a specified level within the ESF. The mechanism controlling radon concentrations in the ESF is a function of atmospheric barometric fluctuations being propagated down the ESF along with ventilated air flow and the slight suction induced by the ventilation exhaust fans at the South Portal of the ESF. These pressure fluctuations are dampened in the TSw fracture continuum according to its …

Accurate timing of ultrafast x-ray probe pulses emitted from a synchrotron radiation source with respect to the signal initiating a process in the sample under study is critical for the investigation of structural dynamics in the femtosecond regime. We describe schemes for achieving accurate timing of femtosecond x-ray synchrotron radiation pulses relative to a pump laser, where x-rays pulses of <100 fs duration are generated from the proposed LUX source based on a recirculating superconducting linac. We present a description of the timing signal generation and distribution systems to minimize timing jitter of the x-rays relative to the experimental lasers.

The Multispectral Thermal Imager (MTI) is a research and development satellite sponsored by the Department of Energy (DOE) for accurate water surface temperature retrieval. MTI uses five thermal spectral bands to retrieve ground temperatures. The application of MTI for land-based temperature and emissivity retrieval has been limited. Savannah River Technology Center conducted several ground truth campaigns at Ivanpah Playa to measure reflectance, temperature and emissivity. The results of MTI temperature and emissivity retrievals and material identification will be discussed in context with the ground truth data.