Rare earth (RE) modification of automotive catalysts (e.g., ZrO{sub 2}) for exhaust gas treatment results in outstanding improvement of the structural stability, catalytic functions and resistance to sintering at high temperatures. Owing to the low redox potential of nonstoichiometric CeO{sub 2}, oxygen release and intake associated with the conversion between the 3+ and 4+ oxidation states of the Ce ions in Ce-doped ZrO{sub 2} provide the oxygen storage capacity that is essentially to effective catalytic functions under dynamic air-to-fuel ratio cycling. Doping tripositive RE ions such as La and Nd in ZrO{sub 2}, on the other hand, introduces oxygen vacancies that affect the electronic and ionic conductivity. These effects, in conjunction with the nanostructure and surface reactivity of the fine powders, present a challenging problem in the development of better ZrO{sub 2}-containing three-way catalysts. We have carried out in-situ small-to-wide angle neutron diffraction at high temperatures and under controlled atmospheres to study the structural phase transitions, sintering behavior, and Ce{sup 3+} {leftrightarrow} Ce{sup 4+} redox process. We found substantial effects due to RE doping on the nature of aggregation of nanoparticles, defect formation, crystal phase transformation, and metal-support interaction in ZrO{sub 2} catalysts for automotive emission control.

Japanese automakers have introduced hybrid passenger cars in Japan and will soon do so in the US. In this paper, we report how we used early computer simulation model results to compare the commercial viability of a hypothetical near-term (next decade) hybrid mid-size passenger car configuration under varying fuel price and driving patterns. The fuel prices and driving patterns evaluated are designed to span likely values for major OECD nations. Two types of models are used. One allows the ''design'' of a hybrid to a specified set of performance requirements and the prediction of fuel economy under a number of possible driving patterns (called driving cycles). Another provides an estimate of the incremental cost of the hybrid in comparison to a comparably performing conventional vehicle. In this paper, the models are applied to predict the NPV cost of conventional gasoline-fueled vehicles vs. parallel hybrid vehicles. The parallel hybrids are assumed to (1) be produced at high volume, (2) use nickel metal hydride battery packs, and (3) have high-strength steel bodies. The conventional vehicle also is assumed to have a high-strength steel body. The simulated vehicles are held constant in many respects, including 0-60 time, engine type, aerodynamic drag coefficient, tire …

The authors have performed the reaction {sup 248}Cm({sup 4}He, {sup 3}He) using 98.5-MeV alpha particles from the IUCF cyclotron to populate high-j states in {sup 249}Cm. A tentative assignment of the K{sub 17/2} component of the 1/2{sup +}[880] Nilsson state has been made.

We present direct measurements of the neutral weak anomalous magnetic dipole moment, a{sub {tau}}{sup w}, and neutral weak electric dipole moment, d{sub {tau}}{sup w}, of the tau lepton. The dipole moments are measured by analyzing the decays of {tau} leptons produced in the annihilation of positrons and longitudinally polarized electrons on the Z boson resonance at the SLC. Using 6736 Z decays to {tau}{sup +} {tau}{sup {minus}} pairs elected from our 1993-1998 data sample we obtain Re(a{sub {tau}}{sup w}) = (0.26 {+-} 1.24) x 10{sup {minus}3}, Im(a{sub {tau}}{sup w}) = ({minus}0.02 {+-} 0.66) x 10{sup {minus}3}, Re(d{sub {tau}}{sup w}) = (0.18 {+-} 0.67) x 10 {sup {minus}17} e {center_dot} cm, and Im(D{sub {tau}}{sup w}) = ({minus}0.26 {+-} 0.37) x 10{sup {minus}17} e {center_dot} cm.

The capability of the NLC run in the {gamma}e collision mode to probe the CP-conserving {gamma}WW and {gamma}ZZ anomalous couplings through the use of the polarization asymmetry is reviewed. When combined with other measurements, very strong constraints on both varieties of anomalous couplings can be obtained. We show that these bounds are complementary to those that can be extracted from data taken at the LHC.

The effect of shrapnel on target chamber components and experiments at large lasers such as the National Ignition Facility at LLNL and the Megajoule Laser at CESTA in France is an important issue in fielding targets and exposure samples. Modeling calculations are likely to be an important component of this effort. Some work in this area has been performed by French workers, who are collaborating with the LLNL on many issues relating to target chamber, experiment-component, and diagnostics survival. Experiments have been performed at the Phebus laser in France to measure shrapnel produced by laser-driven targets; among these shots were experiments that accelerated spheres of a size characteristic of some of the more damaging shrapnel. These spheres were stopped in polyethylene witness plates. The penetration depth is characteristic of the velocity of the shrapnel. Experimental calibration of steel sphere penetration into polyethylene was performed at the CESTA facility. The penetration depth has been reported (ref. 1) and comparisons with modeling calculations have been made (ref. 2). There was interest in a comparison study of the modeling of these experiments to provide independent checks of the calculations. This work has been approved both by DOE headquarters and by the French Atomic …

We present a direct measurement of the parity-violation parameter A{sub c}. The measurement is based on 550k Z{sup 0} decays collected by the SLD detector. The mean electron-beam polarization is |P{sub e}| = 73%. The tagging of c-quark events was performed using two methods: The exclusive reconstruction of D*{sup +}, D{sup +}, and D{sup 0} mesons, and the inclusive P{sub T} spectrum of soft-pions ({pi}{sub s}) in the decay of D*{sup +} {yields} D{sup 0}{pi}{sub s}{sup +}. The results of these two methods are combined to give A{sub c} = 0.688 {+-} 0.035(stat.) {+-} 0.025(sys.) (preliminary).

During Fiscal Year (FY) 1991 and FY 1992, Sandia National Laboratory and Battelle Pacific Northwest Laboratory were assigned the responsibility to generate initial Total System Performance Assessments (TSPAs) of the Yucca Mountain site. The analyses performed by these organizations (called TSPA-1991) are reported in Barnard et al(1992) and Eslinger et al. (1993). During this same time period, Golder Associates Inc. was assigned the task of generating a model capable of analyzing the total system performance of a high-level radioactive waste repository. The developed model, called Repository Integration Program (RIP), is documented in Kossik and Hachey (1993), Miller et al. (1993), and Golder Associates Inc. (1993). In FY 1993, the Civilian Radioactive Waste Management System Contractor was assigned the responsibility to plan, coordinate, and contribute to the second iteration of TSPA-2. Prior to initiating the next TSPA iteration, it was decided that it would be valuable to evaluate the applicability of RIP for use in this iteration. Therefore, analyses were conducted to compare the results generated by RIP to those reported in TSPA-1991. In particular, the aim was to generate a RIP input data set as equivalent as possible to that documented in Barnard et al. (1992) and to analyze the …

There has recently been a study of the potential uses of multimode dielectric structures for wakefield acceleration [1]. This technique is based on adjusting the wakefield modes of the structure to constructively interfere at certain delays with respect to the drive bunch, thus providing an accelerating gradient enhancement over single mode devices. In this report we examine and attempt to clarify the issues raised by this work in the light of the present state of the art in wakefield acceleration.

We consider the interface between a (100) silicon surface and several naturally occurring crystalline silicon dioxide (SiO{sub 2}-silica) polymorphs: {alpha}-quartz, {beta}-cristobalite, tridymite, and keatite. Using a classical empirical potential, we compute the strain energy required for epitaxy for each silica structure. Tridymite is the least energetically favorable epitaxial phase, followed by {alpha}-quartz, then {beta}-cristobalite, while the most energetically favorable phase is keatite. We discuss the implications of this for epitaxial growth, and the crystalline to amorphous transition within atomically thin silica layers.

A high current L-band photocathode rf gun is under development at SRRC (Synchrotron Radiation Research Center, Taiwan) in collaboration with ANL (Argonne National Laboratory, USA). The goal is to produce up to 100 nC charge with the surface field gradient of over 90 MV/m at the center of the photocathode. In this report, they present the detailed design and initial test results. If successful, this gun will be used as the future AWA (Argonne Wakefield Accelerator)[1] high current gun.

The combination of high-brilliance x-ray sources, fast detector systems, wide-bandwidth networks, and parallel computers can substantially reduce the time required to acquire, reconstruct, and visualize high-resolution three-dimensional tomographic datasets. A quasi-realtime computed x-ray microtomography system has been implemented at the 2-BM beamline at the Advanced Photon Source at Argonne National Laboratory. With this system, a complete tomographic data set can be collected in about 15 minutes. Immediately after each projection is obtained, it is rapidly transferred to the Mathematics and Computing Sciences Division where preprocessing and reconstruction calculations are performed concurrently with the data acquisition by a SGI parallel computer. The reconstruction results, once completed, are transferred to a visualization computer that performs the volume rendering calculations. Rendered images of the reconstructed data are available for viewing back at the beamline experiment station minutes after the data acquisition was complete. The fully pipelined data acquisition and reconstruction system also gives us the option to acquire the tomographic data set in several cycles, initially with coarse then with fine angular steps. At present the projections are acquired with a straight-ray projection imaging scheme using 5-20 keV hard x rays in either phase or amplitude contrast mode at a 1-10 pm resolution. …

In this paper we present a design report on a 1-1/2 cell, L Band RF photocathode gun that is capable of generating and accelerating electron beams with peak currents >10 kA. We have performed simulation for bunch intensities in the range of 10-100 nC with peak axial electrical field at the photocathode of 30-100 MV/m. Unlike conventional short electron pulse generation, this design does not require magnetic pulse compression. Based on numerical simulations using SUPERFISH and PARMELA, this design will produce 20-100 nC beam at 18 MeV with rms bunch length 0.6-1.25 mm and normalized transverse emittance 30-108 mm mrad. Applications of this beam for wakefield acceleration is also discussed.

A novel laser Doppler linear encoder system (LDLE) has been developed at the Advanced Photon Source, Argonne National Laboratory. A self-aligning 3-D multiple-reflection optical design was used for the laser Doppler displacement meter (LDDM) to extend the encoder system resolution. The encoder is compact [about 70 mm(H) x 100 mm(W) x 250 mm(L)] and it has sub-Angstrom resolution, 100 mm/sec measuring speed, and 300 mm measuring range. Because the new device affords higher resolution, as compared with commercial laser interferometer systems, and yet cost less, it will have good potential for use in scientific and industrial applications.

Luminosity monitors are needed in each experiment doing spin physics at RHIC. They concentrate on the luminosity aspects here because, for example, with a 10{sup {minus}3} raw asymmetry in an experiment, an error of 10{sup {minus}4} in the luminosity is as significant as a 10% polarization error. Because luminosity is a property of how two beams overlap, the luminosity at an interaction region must be measured at that interaction region in order to be relevant to the experiment at that interaction region. The authors will have to do the physics and the luminosity measurements by using labels on the event sums according to the polarization labels on the colliding bunches. Most likely they will not have independent polarization measurement on each bunch, but only on all the filled bunches in a ring, or perhaps all the bunches that are actually used in an experiment. Most analyses can then be handled by using the nine combinations gotten from three kinds of bunches in each ring, +, {minus} and empty bunches. The empty bunches are needed to measure beam-gas background, (and some, like six in a row, are needed for the beam abort). Much of the difficulty comes from the fact that …

Slow-strain-rate tensile tests (SSRTs) and posttest fractographic analyses by scanning electron microscopy were conducted on 16 austenitic stainless steel (SS) alloys that were irradiated at 289 C in He. After irradiation to {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2} and {approx}0.9 x 10{sup 21} n{center_dot}cm{sup {minus}2} (E >1 MeV), significant heat-to-heat variations in the degree of intergranular and transgranular stress corrosion cracking (IGSCC and TGSCC) were observed. Following irradiation to a fluence of {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2}, a high-purity laboratory heat of Type 316L SS (Si {approx} 0.024 wt%) exhibited the highest susceptibility to IGSCC. The other 15 alloys exhibited negligible susceptibility to IGSCC at this low fluence. The percentage of TGSCC on the fracture surfaces of SSRT specimens of the 16 alloys at {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2} (E > 1 MeV) could be correlated well with N and Si concentrations; all alloys that contained <0.01 wt.% N and <1.0 wt. % Si were susceptible, whereas all alloys that contained >0.01 wt.% N or >1.0 wt.% Si were relatively resistant. High concentrations of Cr were beneficial. Alloys that contain <15.5 wt.% Cr exhibited greater percentages of TGSCC and IGSCC than those alloys with {approx}18 wt.% Cr, whereas …

FTIR and EXAFS spectroscopic measurements were performed on Pb(II)EDTA adsorbed on goethite as functions of pH (4-6), Pb(II)EDTA concentration (0.11 {micro}M - 72 {micro}M), and ionic strength (16 {micro}M - 0.5M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA{sup 2{minus}}. Since substantial uptake of PbEDTA(II){sup 2{minus}} occurred in the samples, we infer that Pb(II)EDTA{sup 2{minus}} adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. We propose the term ''hydration-sphere'' for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups, and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The similarity of Pb(II) uptake isotherms to those of other divalent metal ions complexed by EDTA suggests that they too adsorb by these mechanisms. The lack of …

The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. Over the past decade, a large database identifying the partitioning and emitted concentrations of several toxic metals on the list of HAPs has been developed. Laboratory data have also been generated to help define the general behavior of several elements in combustion systems. These data have been used to develop empirical and probabalistic models to predict emissions of trace metals from coal-fired power plants. While useful for providing average emissions of toxic species, these empirically based models fail when extrapolated beyond their supporting database. This represents a critical gap; over the coming decades, new fuels and combustion systems will play an increasing role in our nation's power generation system. For example, new fuels, such as coal blends or beneficiated fuels, new operating conditions, such as low-NO burners or staged combustion, or new power x systems, for example, those being developed under the DoE sponsored Combustion 2000 programs and integrated …

An invention is described which relates to a patented process and to a motor driven mandrel apparatus (Patent No. 4,546,816) which has the property to roll without slip (or friction) or to roll with controlled friction on the inside surface of a non rotating hollow round. Each point on the circumferential surface of the mandrel describes a hypocycloidal curve or a curve with a hypocycloidal characteristic during the operation of the mandrel.

This project will provide a waste water treatment system to efficiently strip tritium from certain Mound generated waste water streams. After stripping the tritium from the water stream, the tritium will be further purified into a fully reusable form. The by-product streams, both liquid and gaseous, will be within applicable standards and can be released directly to the environment. The major components of the system consist of the following: an organic cleanup unit for the incoming waste stream, to be located inside a new glovebox in SW 149B; catalytic exchange columns and electrolysis cells, and a hydrogen recombiner to be located inside new gloveboxes in T-57; hydride storage beds and a cryogenic distillation unit to be located inside new gloveboxes in T-16; control instrumentation, and tie-in lines to utilities as required. All major components of this system have been tested and successfully operated in a small pilot plant.

As a part of the International Remote Monitoring Project, during March 1995, a Remote Monitoring System (RMS) was installed at the Embalse Nuclear Power Station in Embalse, Argentina. This system monitors the status of four typical Candu spent fuel dry storage silos. The monitoring equipment for each silo consists of analog sensors for temperature and gamma radiation measurement; digital sensors for motion detection; and electronic fiber-optic seals. The monitoring system for each silo is connected to a wireless Authenticate Item Monitoring System (AIMS). This paper describes the operation of the RMS during the first year of the trial and presents the results of the signals reported by the system compared with the on site inspections conducted by the regulatory bodies, ABACC, IAEA, ENREN. As an additional security feature, each sensor periodically transmits authenticated State-of-Health (SOH) messages. This feature provides assurance that all sensors are operational and have not been tampered with. The details of the transmitted information and the incidents of loss of SOH, referred to as Missing SOH Event, and the possible causes which produced the MSOHE are described. The RMS at the embalse facility uses gamma radiation detectors in a strong radiation field of spent fuel dry storage …

Mechanical assembly and maintenance of the prototype National Ignition Facility amplifiers in the Amplifier Module Prototype Laboratory (AMPLAB) at Lawrence Livermore National Laboratory requires specialized equipment designed to manipulate large and delicate amplifier components in a safe and clean manner. Observations made during the operation of this assembly and maintenance equipment in AMPLAB provide design guidance for similar tools being built for the National Ignition Facility. Fixtures used for amplifier frame installation, laser slab and flashlamp cassette assembly, transport, and installation, and in-situ blastshield exchange are presented. Examples include a vacuum slab gripper, slab handling clean crane, slab cassette assembly fixture, sealed transport vehicle for slab cassette movement between the cleanroom and amplifier, slab cassette transfer fixture between the cleanroom and transport vehicle, and equipment needed for frame assembly unit, blastshield, an d flashlamp cassette installation and removal. The use of these tools for amplifier assembly, system reconfiguration, reflector replacement, and recovery from an abnormal occurrence such as a flashlamp explosion is described. Observations are made on the design and operation of these tools and their contribution to the final design.

A steamflood recently initiated by Mobil Development and Production U.S. at the Lost Hills No 3 oil field in California is notable for its shallow depth and the application of electromagnetic (EM) geophysical techniques to monitor the subsurface steam flow. Steam was injected into three stacked eastward-dipping unconsolidated oil sands at depths from 60 to 120 m; the plume is expected to develop as an ellipsoid aligned with the regional northwest-southeast strike. Because of the shallow depth of the sands and the high viscosity of the heavy oil, it is important to track the steam in the unconsolidated sediments for both economic and safety reasons. Crosshole and surface-to-borehole electromagnetic imaging were applied for reservoir characterization and steamflood monitoring. The crosshole EM data were collected to map the interwell distribution of the high-resistivity oil sands and to track the injected steam and hot water. Measurements were made in two fiberglass-cased observation wells straddling the steam injector on a northeast-southwest profile. Field data were collected before the steam drive, to map the distribution of the oil sands, and then 6 and 10 months after steam was injected, to monitor the expansion of the steam chest. Resistivity images derived from the collected data …

Activities during May, 1976, were directed toward installation of the venturi scrubber in the off gas system of the cyclone incinerator and data collection and analysis of samples collected earlier. The report describes the venturi scrubber installation; particulate data; vinyl chloride and hydrocarbon analysis of the off gas stream; HCl determination in the off gas stream; and NOx analysis of the off gas stream.