High statistics W charge asymmetry measurements at the Tevatron {bar p}p collider significantly constrain the u and d quark distributions, and specifically the slope of the d(x)/u(x) in the x range 0.007 to 0.27. The authors present measurements of lepton charge asymmetry as a function of lepton rapidity, A(y{sub l}) at {radical}s = 1.8 TeV for {vert_bar}y{sub l}{vert_bar} < 2.0, for the W decays to electrons and muons recorded by the CDF detector during the 1992-93 run ({approx} 20 pb{sup {minus}1}), and the first {approx} 50 pb{sup {minus}1} of data from the 1994-95 run. These precise data make possible further discrimination between sets of modern parton distributions. In particular it is found that the most recent parton distributions, which included the CDF 1992-93 W asymmetry data in their fits (MRSA, CTEQ3M and GRV94) are still in good agreement with the more precise data from the 1994-95 run. W charge asymmetry results from D0 based on {approx} 6.5 pb{sup {minus}1} data from 1992-1993 run and {approx} 29.7 pb{sup {minus}1} data from 1994-1995 run, using the W decays to muons, are also presented and are found to be consistent with CDF results. In addition, the authors present preliminary measurement of the Drell-Yan …

A detailed chemical kinetic reaction mechanism is used to study the oxidation of n-heptane under several classes of conditions. Experimental results from ignition behind reflected shock waves and in a rapid compression machine were used to develop and validate the reaction mechanism at relatively high temperatures, while data from a continuously stirred tank reactor (cstr) were used to refine the low temperature portions of the reaction mechanism. In addition to the detailed kinetic modeling, a global or lumped kinetic mechanism was used to study the same experimental results. The lumped model was able to identify key reactions and reaction paths that were most sensitive in each experimental regime and provide important guidance for the detailed modeling effort. In each set of experiments, a region of negative temperature coefficient (NTC) was observed. Variation in pressure from 5 to 40 bars were found to change the temperature range over which the NTC region occurred. Both the lumped and detailed kinetic models reproduced the measured results in each type of experiments, including the features of the NTC region, and the specific elementary reactions and reaction paths responsible for this behavior were identified and rate expressions for these reactions were determined.

The Middle Urals is an important Russian industrial region. The key industries are also the most environmentally damaging: mining, metallurgical and chemical industries. There are some 600 large-sized and medium-sized enterprises located within the Middle Urals` region. Their annual solid and gaseous chemical releases have led to exceeding some maximum permissible contaminant concentrations by factors of tens and hundreds. The environmental problems of the Middle Urals are of such magnitude, seriousness, and urgency that the limited available resources can be applied only to the problems of the highest priority in the most cost-effective way. By the combined efforts of scientists from Lawrence Livermore National Laboratory (USA), Institute of Industrial Ecology (Ekaterinburg, Russia) and Russian Federal Nuclear Center (Snezhinsk, Russia) the project on Environmental Priorities Assessment was initiated in 1993. Because the project will cut across a spectrum of Russian environmental, social, and political issues, it has been established as a genuine Russian effort led by Russian principals. Russian participants are the prime movers and decision-makers, and LLNL participants are advisors. A preliminary project has been completed to gather relevant environmental data and to develop a formal proposal for the full priorities assessment project for submittal to the International Science and …

The US DOE through the Mixed Waste Integrated Program, has identified a need to move mixed waste vitrification technology from the laboratory to the field as rapidly as possible. A great deal of work over the last few years has shown the feasibility of immobilizing selected hazardous waste streams in a vitrified product. Lab-scale work has been extended to pilot-scale tests, usually with surrogates of the actual waste. DOE felt that the technology was mature enough to allow demonstration in the field, on actual wastes, with units that would be prototypic of full sized waste treatment equipment. To this end, DOE`s Office of Technology Development sponsored the Westinghouse Savannah River Company (WSRC) to specify, procure, test, and operate a field scale demonstration using mobile equipment. Oak Ridge Reservation was chosen as the initial location for the field demonstration and Martin Marietta Reservation was chosen as the initial location for the field demonstration and Martin Marietta Energy Systems (MMES) tasked with all permitting, site preparation, and field support activities. During September 1993, WSRC used a ``Vendor Forum`` to solicit preliminary proposals for the Transportable Vitrification System (TVS). A number of quality proposals were received and evaluated. A vendor was selected and …

One of the more important uncertainties of using chemical speciation codes to study dissolution and precipitation of compounds is the results of modeling which depends on the particular thermodynamic database being used. The authors goal is to investigate the effects of different thermodynamic databases on modeling precipitation from concentrated solutions. They used the EQ3/6 codes and the supplied databases to model precipitation in this paper. One aspect of this goal is to compare predictions of precipitation from ideal solutions to similar predictions from nonideal solutions. The largest thermodynamic databases available for use by EQ3/6 assume that solutions behave ideally. However, two databases exist that allow modeling nonideal solutions. The two databases are much less extensive than the ideal solution data, and they investigated the comparability of modeling ideal solutions and nonideal solutions. They defined four fundamental problems to test the EQ3/6 codes in concentrated solutions. Two problems precipitate Ca(OH){sub 2} from solutions concentrated in Ca{sup ++}. One problem tests the precipitation of Ca(OH){sub 2} from high ionic strength (high concentration) solutions that are low in the concentrations of precipitating species (Ca{sup ++} in this case). The fourth problem evaporates the supernatant of the problem with low concentrations of precipitating species. …

The primary reference fuels n-heptane and iso-octane and their mixtures are used as a measure of the tendency of a given automotive fuel to cause knocking or pre-ignition in an internal combustion engine. Consequently, many experimental studies have been performed on these hydrocarbons in an attempt to better understand their oxidation. Shock tube studies at high temperature and pressure have been performed. Low temperature studies, in which species concentration profiles of primary, intermediate and final products, have been carried out using jet stirred flow reactors. In addition, experiments have been performed in CFR engines and fundamental features of n-heptane autoignition have been observed using a rapid compression machine. A detailed chemical kinetic reaction mechanism is employed here to study the oxidation of both fuels. Computed results are compared with experimental data obtained in the High Pressure Turbulent Flow Reactor at Princeton University.

Westinghouse Savannah River Company is implementing productivity improvement concepts into the Waste Minimization Program by focusing on the positive initiatives taken to reduce waste generation at the Savannah River Site. Previous performance measures, based only on waste generation rates, proved to be an ineffective metric for measuring performance and promoting continuous improvements within the Program. Impacts of mission changes and non-routine operations impeded development of baseline waste generation rates and often negated waste generation trending reports. A system was developed to quantify, document and track innovative activities that impact waste volume and radioactivity/toxicity reductions. This system coupled with Management-driven waste disposal avoidance goals is proving to be a powerful tool to promote waste minimization awareness and the implementation of waste reduction initiatives. Measurement of waste not generated, in addition to waste generated, increases the credibility of the Waste Minimization Program, improves sharing of success stories, and supports development of regulatory and management reports

At the Lawrence Livermore National Laboratory, we have prepared a Safety Analysis Report for the Department of Energy on our Building 332 Plutonium Handling Facility. This SAR includes an analysis of potential accident scenarios which could lead to offsite consequences to the public having not only radiological exposures, but also exposures to toxic gases such as chlorine. This paper presents a risk analysis of pressurized chlorine gas system proposed for use at Building 332. The focus of the analysis is to calculate the predicted frequency of an unmitigated leak of chlorine from the system which could result in the dispersal of the entire contents of the gas cylinder to the environment. Modeled are postulated valve leaks or pipe ruptures occurring anywhere in the distribution system, as well as the potential failure of leak mitigation. The fundamental credibility of this type of accident is established. The importance of a reliable leak mitigation system is demonstrated, and the dependence of the results on less than optimal data is discussed in the context of uncertainty and sensitivity analyses.

At the Oak Ridge Y-12 Plant, there are numerous situations in which nuclear criticality safety must be assured and subcriticality demonstrated by some method other than the straightforward use of the double contingency principle. Some cases are cited, and the criticality safety evaluation of contaminated combustible waste collectors is considered in detail. The criticality safety evaluation for combustible collectors is based on applying one very good control to the one controllable parameter. Safety can only be defended when the contingency of excess density is limited to a credible value based on process knowledge. No reasonable single failure is found that will result in a criticality accident. The historically accepted viewpoint is that this meets double contingency, even though there are not two independent controls on the single parameter of interest.

Risk assessment techniques vary from purely qualitative approaches, through a regime of semi-qualitative to the more traditional quantitative. Constraints such as time, money, manpower, skills, management perceptions, risk result communication to the public, and political pressures all affect the manner in which risk assessments are carried out. This paper surveys some risk matrix techniques, examining the uses and applicability for each. Limitations and problems for each technique are presented and compared to the others. Risk matrix approaches vary from purely qualitative axis descriptions of accident frequency vs consequences, to fully quantitative axis definitions using multi-attribute utility theory to equate different types of risk from the same operation.

Lawrence Livermore National Laboratory (LLNL)l is developing a prototype imaging radar for inspecting steel reinforced concrete bridge decks. The system is designed to acquire Synthetic Aperture Radar (SAR) data and provide high-resolution images of internal structure, flaws, and defects enabling bridge inspectors to nondestructively evaluate and characterize bridge deck condition. Concrete delamination resulting from corrosion of steel reinforcing bars (rebars) is an important structural defect that the system is designed to detect. The prototype system uses arrays of compact, low-cost Micropower Impulse Radar (MIR) modules, supported by appropriate data acquisition and storage subsystems, to generate and collect the radar data, and unique imaging codes to reconstruct images of bridge deck internals. In this paper, we provide an overview of the prototype system concept, discuss its expected performance, and present recent experimental results showing the capability of this approach to detect thin delamination simulations embedded in concrete.

Recent QCD results from the CDF and D0 experiments at the Fermilab Tevatron collider are reviewed.

This paper reports on the feasibility of using Acoustic Emission (AE) for sensing the proximity of a grinding wheel to a glass workpiece, both prior to contact and in the early stages of contact. Our measured AE signals indicate that we can track the position of the grinding wheel as it approaches the workpiece through the turbulent coolant layer and than as contact initiates with a workpiece during spherical generation. Our data for the initial contact region is dominated by cyclical bursts of AE that appear to correspond to tool spindle motion errors. Our principal goal is to minimize the time required to {open_quote}find the part{close_quote} without damaging the surface of a brittle workmaterial, i.e. during the transition from a fast approach to the much slower final in-feed required for the grinding operation. Our results also suggest that AE is useful as a gauging signal in determining the position of the grinding wheel with respect to the machine tool.

Microscopic time reversibility and macroscopic irreversibility are a paradoxical combination. This was first observed by J. Loschmidt in 1876 and was explained, for conservative systems, by L. Boltzmann the following year. Both these features are also present in modern simulations of classic many-body systems in steady nonequilibrium states. We illustrate them here for the simplest possible models, a continuous one-dimensional model of field-driven diffusion, the so-called driven Lorentz gas or Galton Board, and an ergodic time reversible dissipative map.

This paper describes a relatively inexpensive, fast, and easy to execute approach to mapping the volumetric errors of a machine tool, coordinate measuring machine, or robot. An error map is used to characterize a machine or to improve its accuracy by compensating for the systematic errors. The method consists of three steps: (1) modeling the relationship between the volumetric error and the current state of the machine; (2) acquiring error data based on length measurements throughout the work volume; and (3) optimizing the model to the particular machine.

The NORAPS model has been used to simulate the motion of Hurricane Erin over Florida. A triplynested grid was used to capture the meteorological features which span from regional to local scales with the highest resolution nest centered at the Kennedy Space Center area. The simulated storm track agreed remarkably well with the observed path of the hurricane. There was also good qualitative agreement between the computed surface precipitation pattern and observations based on radar signatures. Although the validity of the Kuo- type cumulus parameterization scheme used in the model was marginal and even questionable on the finest resolution (4 km) nest, the simulated results were nevertheless qualitatively reasonable. The results generated by NORAPS from the simulation of such a numerical challenging meteorological event were very encouraging. Our next step is to use the meteorological information from the model to provide wind fields for dispersion model simulations of potential atmospheric releases.