Ecological risk assessment (ERA) is a tool used by many regulatory agencies to evaluate the impact to ecological receptors from changes in environmental conditions. Widespread use of ERAs began with the United States Environmental Protection Agency's Superfund program to assess the ecological impact from hazardous chemicals released to the environment. Many state hazardous chemical regulatory agencies have adopted the use of ERAs, and several state regulatory agencies are evaluating the use of ERAs to assess ecological impacts from releases of petroleum and gas-related products. Typical ERAs are toxicologically-based, use conservative assumptions with respect to ecological receptor exposure duration and frequency, often require complex modeling of transport and exposure and are very labor intensive. In an effort to streamline the ERA process, efforts are currently underway to develop default soil screening levels, to identify ecological screening criteria for excluding sites from formal risk assessment, and to create risk-based corrective action worksheets. This should help reduce the time spent on ERAs, at least for some sites. Work is also underway to incorporate bioavailability and spatial considerations into ERAs. By evaluating the spatial nature of contaminant releases with respect to the spatial context of the ecosystem under consideration, more realistic ERAs with respect …

The MINOS experiment is a long-baseline, neutrino-oscillation experiment. In total, 28,000 m{sup 2} of scintillator is needed for the experiment. This is almost 300 tons of finished scintillator. The solution has been the development of an extruded scintillator with a 2-mm deep grove in the upper surface for a wavelength-shifting fiber and a co-extruded TiO{sub 2} coating as a reflector. The TiO{sub 2} coating also allows the scintillator to be directly epoxied into panels. Production and quality control techniques are presented.

Over the course of testing a substantial number of KDP and DKDP crystals from rapid and conventional growth processes, we have discovered that there is a consistent difference in the value of the damage resistance between z-cut and tripler, x-cut and y-cut crystals for a given test fluence. This increase in damage probability for tripler, x and y-cut crystals is consistent for both conventional and rapid growth KDP as well as DKDP. It also holds for unconditioned (S/1) and conditioned (R/l) tests and has values of 2.1 {+-} 0.6 and 1.5 {+-} 0.3 respectively. Testing has also revealed that there is no sensitivity to incident laser polarization. This is in direct contradiction to models based on simple, non-spherical absorbers. This result plus new information on the size and evolution of bulk damage density (see Runkel et al., this proceedings) has led to a reinterpretation of the growth parameter data for rapid growth NIF boules. It now appears that variations in impurity concentration throughout the boule do not affect the damage probability curve as dramatically as previously thought; although, this is still a topic of intensive investigation.

This paper discusses the results of thermal annealing and in-situ second harmonic generation (SHG) damage tests performed on six rapid growth KDP type 1 doubler crystals at 1064 nm (1 {omega}) on the Zeus automated damage test facility. Unconditioned (S/1) and conditioned (R/1) damage probability tests were performed before and after thermal annealing, then with and without SHG on six doubler crystals from the NIF-size, rapid growth KDP boule F6. The tests revealed that unannealed, last-grown material from the boule in either prismatic or pyramidal sectors exhibited the highest damage curves. After thermal annealing at 160 C for seven days, the prismatic sector samples increased in performance ranging from 1.6 to 2.4X, while material from the pyramidal sector increased only modestly, ranging from 1.0 to 1.4X. Second harmonic generation decreased the damage fluence by an average of 20 percent for the S/1 tests and 40 percent for R/1 tests. Conversion efficiencies under test conditions were measured to be 20 to 30 percent and compared quite well to predicted behavior, as modeled by LLNL frequency conversion computer codes. The damage probabilities at the 1 {omega} NIF redline fluence (scaled to 10 ns via t{sup 0.5}) for S/1 tests for the unannealed …

A radiation-hard pixel readout chip, FPIX2, is being developed at Fermilab for the recently approved BTeV experiment. Although designed for BTeV, this chip should also be appropriate for use by CDF and DZero. A short review of this development effort is presented. Particular attention is given to the circuit redesign which was made necessary by the decision to implement FPIX2 using a standard deep-submicron CMOS process rather than an explicitly radiation-hard CMOS technology, as originally planned. The results of initial tests of prototype 0.25{micro} CMOS devices are presented, as are plans for the balance of the development effort.

Laser conditioning has been shown to improve the laser damage threshold of some optical coatings by greater than 2x. Debate continues within the damage community regarding laser-conditioning mechanisms, but it is clear that nodular ejection is one of the byproducts of the laser conditioning process. To better understand why laser conditioning is so effective, photothermal microscopy was used to measure absorption of coating defects before and after laser exposure. Although a modest absorption reduction was expected due to the lower electric field peaks within a pit and the absence of potentially absorbing nodular seeds, surprisingly, absorption reductions up to 150x were observed. Photothermal microscopy has also been successfully used to correlate laser-induced damage threshold and absorption of defects in hafnia/silica multilayer optical coatings. Defects with high absorption, as indicated by high photothermal signal, have low damage thresholds. Previously a linear correlation of damage threshold and defect photothermal signal was established with films designed and damage tested at 1{omega} (1053 nm) and Brewster's angle (56.4{sup o}), but characterized by photothermal microscopy at 514.5 nm and near-normal angle of incidence (10{sup o}). In this study coatings designed, characterized by photothermal microscopy, and damage tested at the same wavelength, incident angle, and polarization …

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Population synthesis studies of binaries are always limited by a myriad of uncertainties from the poorly understood effects of binary mass transfer and common envelope evolution to the many uncertainties that still remain in stellar evolution. But the importance of these uncertainties depends both upon the objects being studied and the questions asked about these objects. Here I review the most critical uncertainties in the population synthesis of gamma-ray burst progenitors. With a better understanding of these uncertainties, binary population synthesis can become a powerful tool in understanding, and constraining, gamma-ray burst models. In turn, as gamma-ray bursts become more important as cosmological probes, binary population synthesis of gamma-ray burst progenitors becomes an important tool in cosmology.

The technical papers presented in this special publication represent the efforts of students from 16 colleges and universities across North America. Over 600 students have participated in the Ethanol Vehicle Challenge since its inception in 1998. The 2000 Ethanol Vehicle Challenge was the final year of this successful 3-year advanced vehicle competition series. The papers presented are enhanced and expanded versions of those prepared in advance of the competition by the participating student engineers. They describe the design elements, construction details, and performance of the dedicated ethanol vehicles brought to the Challenge by the participating universities. The goal of this competition was to demonstrate the potential of E85 (85% denatured ethanol and 15% hydrocarbon primer) to significantly lower emissions and improve the performance, fuel efficiency and cold starting of vehicles fueled by ethanol. The competition series began with a Request for Proposals in January 1997. A letter announcing and soliciting interest in the competition (Notice of Interest) was sent to all accredited engineering programs and two-year technical schools in the US and Canada. The Notice described the competition and the requirements for the conversion of a 1997 Chevrolet Malibu to dedicated E85 operation. On the basis of the submitted proposals, …

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Results are reported from recently performed bulk-damage, pulse-scaling experiments on DKDP tripler samples taken from NIF-size, rapid-growth boule BD7. The tests were performed on LLNL's Optical Sciences Laser. A matrix of samples was exposed to single shots at 351 mn (3 {omega}) with average fluences from 4 to 8 J/cm{sup 2} for pulse durations of 1, 3 and 10 ns. The damage sites were scatter-mapped after testing to determine the damage evolution as a function of local beam fluence. The average bulk damage microcavity (pinpoint) density varied nearly linearly with fluence with peak values of approximately 16,000 pp/mm{sup 3} at 1 ns, 10,000 pp/mm{sup 3} at 3 ns and 400 pp/mm{sup 3} at 10 ns for fluences in the 8-10 J/cm{sup 2} range. The average size of a pinpoint was 10(+14,-9) {micro}m at 1 ns, 37 {+-} 20 {micro}m at 3 ns and {approx} 110 {micro}m at 10 ns, although all pulse durations produced pinpoints with a wide distribution of sizes. Analysis of the pinpoint density data yielded pulse-scaling behavior of t{sup 0.35}. Significant planar cracking around the pinpoint as was observed for the 10 ns case but not for the 1 and 3 ns pulses. Crack formation around pinpoints …

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The problem of generating light neutrinos within supersymmetric models is discussed. It is shown that the hierarchy of scales induced by supersymmetry breaking can give rise to suppression factors of the correct order of magnitude to produce experimentally allowed neutrino spectra.

Undulator beamlines at third-generation synchrotrons x-ray sources are designed to use the high-brilliance radiation that is contained in the central cone of the generated x-ray beams. The rest of the x-ray beam is often unused. Moreover, in some cases, such as in the zone-plate-based microfocusing beamlines, only a small part of the central radiation cone around the optical axis is used. In this paper, a side-station branch line at the Advanced Photon Source that takes advantage of some of the unused off-axis photons in a microfocusing x-ray beamline is described. Detailed information on the design and analysis of a high-heat-load water-cooled monochromator developed for this beamline is provided.

We present results for the 8:1 thermal cavity problem using FIDAP on 3 meshes--each using 3 elements. A brief summary of related results is also included. This contribution comes via the rather versatile and general commercial finite element code, FIDAP. This code still offers the user a wide selection with respect to element choices, statement of governing equations, (e.g., advective form, divergence form) implicit time integrators (variable-step or fixed step, first-order or second-order), and solution techniques for both the nonlinear and linear sets of equations. We have tested quite a number of these variations on this problem; here we report on an interesting subset and will present the remainder at the conference.

Nonlinear edge preserving smoothing often is performed prior to medical image segmentation. The goal of the nonlinear smoothing is to improve the accuracy of the segmentation by preserving changes in image intensity at the boundaries of structures of interest, while smoothing random variations due to noise in the interiors of the structures. Methods include median filtering and morphology operations such as gray scale erosion and dilation, as well as spatially varying smoothing driven by local contrast measures. Rather than irreversibly altering the image data prior to segmentation, the approach described here has the potential to unify nonlinear edge preserving smoothing with segmentation based on differential edge detection at multiple scales. The analysis of n-D image data is decomposed into independent 1-D problems that can be solved quickly. Smoothing in various directions along 1-D profiles through the n-D data is driven by a measure of local structure separation, rather than by a local contrast measure. Isolated edges are preserved independent of their contrast, given an adequate contrast to noise ratio.

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At the Thirteenth International Symposium on Heavy Ion Inertial Fusion (HIF Symposium), we presented magnet shielding calculations for 72-, 128, 200, and 288-beam versions of the HYLIFE-II power plant design. In all cases, we found the radiation-limited lifetimes of the last set of final focusing magnets to be unacceptably short. Since that time, we have completed follow-on calculations to improve the lifetime of the 72-beam case. Using a self-consistent final focusing model, we vary parameters such as the shielding thicknesses and compositions, focusing length, angle-of-attack to the target, and the geometric representation of the flibe pocket, chamber, and blanket. By combining many of these shielding features, we are able to demonstrate a magnet shielding design that would enable the last set of final focusing magnets to survive for the lifetime of the power plant.

A 24 g aluminum sphere was shot at a sparse array of cylinders with nominal initial projectile velocity of 4 and 5 km/s. Pressure profiles were measured with cased carbon resistor gages at two locations in a projectile impacted water filled cylinder and two of its neighbors on three shots. The pressure maxima were in the 1-13 kbars range. The experiments are modeled with the ALE3D code and several techniques are used to concentrate zoning at places of interest. There is excellent agreement between the measured and calculated pressure profiles for two shots and good agreement for the third. Comparison of the calculated pressure profiles with those from more refined calculations for two shots suggest that we are near convergence with respect to zone size.

The production of nuclei up to and including the light s-process component at A {approx} 60-90 is calculated for all stages of stable and explosive nuclear burning in stars of 15 and 25 M{sub {circle_dot}}. An extended nuclear reaction network of 480 isotopes is employed along with approximately two dozen recent revisions to key nuclear reaction rates. As noted previously, the new rates suggest a greatly diminished production of {sup 17}O and {sup 18}O in massive stars. {sup 22}Ne is also moderately enhanced. We find that a combination of pre-explosive s-process, {gamma}-process, and (mild) r-processes in massive stars give a consistently solar production of almost all isotopes from mass 64 through 90. However, even after the late stages of evolution are complete and the explosion is over, this same group of elements is overproduced compared to what is needed for the sun, especially in the 25 M{sub {circle_dot}} model.

The present work continues our effort to perform an integrated safety analysis for the HYLIFE-II inertial fusion energy (IFE) power plant design. Recently we developed a base case for a severe accident scenario in order to calculate accident doses for HYLIFE-II. It consisted of a total loss of coolant accident (LOCA) in which all the liquid flibe (Li{sub 2}BeF{sub 4}) was lost at the beginning of the accident. Results showed that the off-site dose was below the limit given by the DOE Fusion Safety Standards for public protection in case of accident, and that his dose was dominated by the tritium released during the accident.

A new and different time variant pulse processing system has been developed based on a simple CR-RC filter and two analog switches. The new pulse processing technique combines both ballistic deficit immunity and resilience to parallel noise without a significant compromise to the low energy resolution, generally considered a mutually exclusive requirement. The filter is realized by combining two different pulse-shaping techniques. One of the techniques creates a low rate of curvature at the pulse peak, which reduces ballistic deficit, while the second technique increases the tolerance to low frequency noise by modifying the noise history. Several experimental measurements are presented, including tests on a co-planar grid CdZnTe detector. Improvements on both the resolution and line shape are shown for the 662 keV line of 137Cs.

Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support.