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Adding static printing capabilities to the EUV phase-shifting point diffraction interferometer (open access)

Adding static printing capabilities to the EUV phase-shifting point diffraction interferometer

While interferometry is routinely used for the characterization and alignment of lithographic optics, the ultimate performance metric for these optics is printing in photoresist. Direct comparison of imaging and wavefront performance is also useful for verifying and improving the predictive power of wavefront metrology under actual printing conditions. To address these issues, static, small-field printing capabilities are being added to the extreme ultraviolet (EUV) phase-shifting point diffraction interferometer (PS/PDI) implemented at the Advanced Light Source at Lawrence Berkeley National Laboratory. This Sub-field Exposure Station (SES) will enable the earliest possible imaging characterization of the upcoming Engineering Test Stand (ETS) Set-2 projection optics. Relevant printing studies with the ETS projection optics require illumination partial coherence with {sigma} of approximately 0.7. This {sigma} value is very different from the coherent illumination requirements of the EUV PS/PDI and the coherence properties naturally provided by synchrotron undulator beamline illumination. Adding printing capabilities to the PS/PDI experimental system thus necessitates the development of an alternative illumination system capable of destroying the inherent coherence of the beamline. The SES is being implemented with two independent illuminators: the first is based on a novel EUV diffuser currently under development and the second is based on a scanning …
Date: March 1, 2001
Creator: Naulleau, Patrick; Goldberg, Kenneth A.; Anderson, Erik H.; Batson, Phillip; Denham, Paul; Jackson, Keith et al.
System: The UNT Digital Library
Advances in understanding paternally transmitted Chromosomal Abnormalities (open access)

Advances in understanding paternally transmitted Chromosomal Abnormalities

Multicolor FISH has been adapted for detecting the major types of chromosomal abnormalities in human sperm including aneuploidies for clinically-relevant chromosomes, chromosomal aberrations including breaks and rearrangements, and other numerical abnormalities. The various sperm FISH assays have been used to evaluate healthy men, men of advanced age, and men who have received mutagenic cancer therapy. The mouse has also been used as a model to investigate the mechanism of paternally transmitted genetic damage. Sperm FISH for the mouse has been used to detect chromosomally abnormal mouse sperm, while the PAINT/DAPI analysis of mouse zygotes has been used to evaluate the types of chromosomal defects that can be paternally transmitted to the embryo and their effects on embryonic development.
Date: March 1, 2001
Creator: Marchetti, F; Sloter, E & Wyrobek, A J
System: The UNT Digital Library
AN ALGORITHM FOR PARALLEL SN SWEEPS ON UNSTRUCTURED MESHES (open access)

AN ALGORITHM FOR PARALLEL SN SWEEPS ON UNSTRUCTURED MESHES

We develop a new algorithm for performing parallel S{sub n} sweeps on unstructured meshes. The algorithm uses a low-complexity list ordering heuristic to determine a sweep ordering on any partitioned mesh. For typical problems and with ''normal'' mesh partitionings we have observed nearly linear speedups on up to 126 processors. This is an important and desirable result, since although analyses of structured meshes indicate that parallel sweeps will not scale with normal partitioning approaches, we do not observe any severe asymptotic degradation in the parallel efficiency with modest ({le} 100) levels of parallelism. This work is a fundamental step in the development of parallel S{sub n} methods.
Date: March 1, 2001
Creator: PAUTZ, S. D.
System: The UNT Digital Library
ANALYSIS OF 3-D URBAN DATABASES WITH RESPECT TO POLLUTION DISPERSION FOR A NUMBER OF EUROPEAN AND AMERICAN CITIES (open access)

ANALYSIS OF 3-D URBAN DATABASES WITH RESPECT TO POLLUTION DISPERSION FOR A NUMBER OF EUROPEAN AND AMERICAN CITIES

Models to estimate pollution dispersion and wind flow in cities (both at the city-scale and above) require a parametrical description of the urban canopy. For instance, two key parameters are the aerodynamic roughness length z{sub 0} and the zero-plane displacement height z{sub d}, which are related, amongst others, to the surface drag coefficient, the scale and intensity of turbulence, the depth of the roughness sub-layer and the wind speed profile. The calculation of z{sub 0} and z{sub d}, however, is not straightforward. The classical way to estimate them in open terrain is based on the measurement of wind profile data from a tall mast or, less accurately, on the inference from published roughness values for similar terrain elsewhere (Davenport, 1960; Davenport et al., 2000). Both methods, however, are very difficult to apply to cities, due to the considerable height where wind measurements should be taken (well above the urban canopy) and to the irregularities of urban texture. A promising alternative that has become available in recent years, due to increasing computing resources and the availability of high-resolution 3-D databases in urban areas, is based on the calculation of z{sub 0} and z{sub d} from the analysis and measure of the …
Date: March 1, 2001
Creator: RATTI, C. & AL, ET
System: The UNT Digital Library
AUTOMATED PARAMETRIC EXECUTION AND DOCUMENTATION FOR LARGE-SCALE SIMULATIONS (open access)

AUTOMATED PARAMETRIC EXECUTION AND DOCUMENTATION FOR LARGE-SCALE SIMULATIONS

A language has been created to facilitate the automatic execution of simulations for purposes of enabling parametric study and test and evaluation. Its function is similar in nature to a job-control language, but more capability is provided in that the language extends the notion of literate programming to job control. Interwoven markup tags self document and define the job control process. The language works in tandem with another language used to describe physical systems. Both languages are implemented in the Extensible Markup Language (XML). A user describes a physical system for simulation and then creates a set of instructions for automatic execution of the simulation. Support routines merge the instructions with the physical-system description, execute the simulation the specified number of times, gather the output data, and document the process and output for the user. The language enables the guided exploration of a parameter space and can be used for simulations that must determine optimal solutions to particular problems. It is generalized enough that it can be used with any simulation input files that are described using XML. XML is shown to be useful as a description language, an interchange language, and a self-documented language.
Date: March 1, 2001
Creator: KELSEY, R. L. & AL, ET
System: The UNT Digital Library
Automated Sorting of Transuranic Waste (open access)

Automated Sorting of Transuranic Waste

The HANDSS-55 Transuranic Waste Sorting Module is designed to sort out items found in 55-gallon drums of waste as determined by an operator. Innovative imaging techniques coupled with fast linear motor-based motion systems and a flexible end-effector system allow the operator to remove items from the waste stream by a touch of the finger. When all desired items are removed from the waste stream, the remaining objects are automatically moved to a repackaging port for removal from the glovebox/cell. The Transuranic Waste Sorting Module consists of 1) a high accuracy XYZ Stereo Measurement and Imaging system, 2) a vibrating/tilting sorting table, 3) an XY Deployment System, 4) a ZR Deployment System, 5) several user-selectable end-effectors, 6) a waste bag opening system, 7) control and instrumentation, 8) a noncompliant waste load-out area, and 9) a Human/Machine Interface (HMI). The system is modular in design to accommodate database management tools, additional load-out ports, and other enhancements. Manually sorting the contents of a 55-gallon drum takes about one day per drum. The HANDSS-55 Waste Sorting Module is designed to significantly increase the throughput of this sorting process by automating those functions that are strenuous and tiresome for an operator to perform. The Waste …
Date: March 1, 2001
Creator: Shurtliff, Rodney Marvin
System: The UNT Digital Library
Building Safer Communities: The Integrated Community Safety Approach (open access)

Building Safer Communities: The Integrated Community Safety Approach

This paper discusses an integrated community safety approach to creating safer communities. It defines community broadly to include two categories of community members: “industry” and “neighbors.” Potential community members within the “industry” category include facilities, government/regulators, customers, stockholders, and suppliers. Within the “neighbors” category are towns, cities, counties, states; people/commodity flow systems; news media and special interest groups; environment; and families of employees. Each of these potential community members and its characteristics are discussed. The integrated community safety approach consists of three major activities: (1) define the boundaries of the community; (2) facilitate the sense of community; and (3) address the needs of the community. Defining the boundaries of the community includes determining the geographical and social boundaries; this is accomplished through conducting a hazard analysis and community involvement to identify all of the community members. Facilitating the sense of community includes conducting a capability/needs assessment and continuing community involvement to identify the issues and concerns of community members. Addressing the needs of the community involves master planning to consider safety issues in all community development actions and continuing community education and involvement. The integrated community safety approach is a workable approach for existing industries and their neighbors as well …
Date: March 1, 2001
Creator: Fawcett, Ricky Lee; Kerr, Thomas A & Jordan, Steven Albert
System: The UNT Digital Library
Carbon sequestration with enhanced gas recovery: Identifying candidate sites for pilot study (open access)

Carbon sequestration with enhanced gas recovery: Identifying candidate sites for pilot study

Depleted natural gas reservoirs are promising targets for carbon dioxide sequestration. Although depleted, these reservoirs are not devoid of methane, and carbon dioxide injection may allow enhanced production of methane by reservoir repressurization or pressure maintenance. Based on the favorable results of numerous simulation studies, we propose a field test of the Carbon Sequestration with Enhanced Gas Recovery (CSEGR) process. The objective of the field test is to evaluate the feasibility of CSEGR in terms of reservoir processes such as injectivity, repressurization, flow and transport of carbon dioxide, and enhanced production of methane. The main criteria for the field site include small reservoir volume and high permeability so that increases in pressure and enhanced recovery will occur over a reasonably short time period. The Rio Vista Gas Field in the delta of California's Central Valley offers potential as a test site, although we are currently looking broadly for other potential sites of opportunity.
Date: March 1, 2001
Creator: Oldenburg, C.M. & Benson, S.M.
System: The UNT Digital Library
THE CERRO GRANDE FIRE, LOS ALAMOS, NEW MEXICO (open access)

THE CERRO GRANDE FIRE, LOS ALAMOS, NEW MEXICO

None
Date: March 1, 2001
Creator: WEBB, M. D. & CARPENTER, K.
System: The UNT Digital Library
Chiral Extrapolation of Lattice Moments of Proton Quark Distributions (open access)

Chiral Extrapolation of Lattice Moments of Proton Quark Distributions

The behavior of the first three nontrivial moments of the nonsinglet quark distribution u - d in the proton is studied as a function of quark mass in order to guide the extrapolation of lattice QCD calculations to the physical region. We propose a simple extrapolation formula, embodying the general constraints of the chiral symmetry of QCD, which provides an excellent fit to the lattice data and the experimental values for each moment.
Date: March 1, 2001
Creator: W. Detnold, W. Melnitchouk, et. Al.
System: The UNT Digital Library
The Clean Air Act and Renewable Energy: Opportunities, Barriers, and Options (open access)

The Clean Air Act and Renewable Energy: Opportunities, Barriers, and Options

This paper examines the opportunities, obstacles, and potential options to promote renewable energy under the CAA and related programs. It deals, in sequence, with the regulation of SO2, NOx, regional haze/particulate matter, and CO2. For each pollutant, the paper discusses the opportunities, barriers, and options for boosting renewables under the CAA. It concludes by comparing the options discussed. The paper is based on a project on environmental regulation and renewable energy in electricity generation conducted by the National Renewable Energy Laboratory for the Office of Power Technologies, Office of Energy Efficiency and Renewable Energy, US Department of Energy.
Date: March 1, 2001
Creator: Wooley, D.R. (Young, Sommer, Ward, Ritzenberg, Wooley, Baker and Moore, LLC); Morss, E.M. (Young, Sommer, Ward, Ritzenberg, Wooley, Baker and Moore, LLC) & Fang, J.M. (National Renewable Energy Laboratory)
System: The UNT Digital Library
THE COLOR DIPOLE APPROACH TO THE DRELL-YAN PROCESS IN PA COLLISIONS (open access)

THE COLOR DIPOLE APPROACH TO THE DRELL-YAN PROCESS IN PA COLLISIONS

In the target rest frame and at high energies, Drell-Yan (DY) dilepton production looks like bremsstrahlung of massive photons, rather than parton annihilation. The projectile quark is decomposed into a series of Fock states. Configurations with fixed transverse separations are interaction eigenstates for pp scattering. The DY cross section can then be expressed in terms of the same color dipole cross section as DIS. This approach is especially suitable to describe nuclear effects, since it allows to apply Glauber multiple scattering theory. We go beyond the Glauber eikonal approximation by taking into account transitions between interaction eigenstates. We calculate nuclear shadowing at large Feynman-x{sub f} for DY in proton-nucleus collisions, compare to existing data from E772 and make predictions for RHIC. Nuclear effects on the transverse momentum distribution are also investigated.
Date: March 1, 2001
Creator: KOPELIOVICH, B. & AL, ET
System: The UNT Digital Library
A COMPARISON OF FOUR METHODS FOR DETERMINING PRECIPITABLE WATER VAPOR CONTENT FROM MULTI-SPECTRAL DATA (open access)

A COMPARISON OF FOUR METHODS FOR DETERMINING PRECIPITABLE WATER VAPOR CONTENT FROM MULTI-SPECTRAL DATA

Determining columnar water vapor is a fundamental problem in remote sensing. This measurement is important both for understanding atmospheric variability and also from removing atmospheric effects from remotely sensed data. Therefore discovering a reliable and if possible automated method for determining water vapor column abundance is important. There are two standard methods for determining precipitable water vapor during the daytime from multi-spectral data. The first method is the Continuum Interpolated Band Ratio (CIBR) (see for example King et al. 1996). This method assumes a baseline and measures the depth of a water vapor feature as compared to this baseline. The second method is the Atmospheric Pre-corrected Differential Absorption technique (APDA) (see Schlaepfer et al. 1998); this method accounts for the path radiance contribution to the top of atmosphere radiance measurement which is increasingly important at lower and lower reflectance values. We have also developed two methods of modifying CIBR. We use a simple curve fitting procedure to account for and remove any systematic errors due to low reflectance while still preserving the random spread of the CIBR values as a function of surface reflectance. We also have developed a two-dimensional look-up table for CIBR; CIBR using this technique is a …
Date: March 1, 2001
Creator: HIRSCH, K. & AL, ET
System: The UNT Digital Library
COMPARISON OF MONTE CARLO METHODS FOR NONLINEAR RADIATION TRANSPORT (open access)

COMPARISON OF MONTE CARLO METHODS FOR NONLINEAR RADIATION TRANSPORT

Five Monte Carlo methods for solving the nonlinear thermal radiation transport equations are compared. The methods include the well-known Implicit Monte Carlo method (IMC) developed by Fleck and Cummings, an alternative to IMC developed by Carter and Forest, an ''exact'' method recently developed by Ahrens and Larsen, and two methods recently proposed by Martin and Brown. The five Monte Carlo methods are developed and applied to the radiation transport equation in a medium assuming local thermodynamic equilibrium. Conservation of energy is derived and used to define appropriate material energy update equations for each of the methods. Details of the Monte Carlo implementation are presented, both for the random walk simulation and the material energy update. Simulation results for all five methods are obtained for two infinite medium test problems and a 1-D test problem, all of which have analytical solutions. Conclusions regarding the relative merits of the various schemes are presented.
Date: March 1, 2001
Creator: MARTIN, W. R. & BROWN, F. B.
System: The UNT Digital Library
COMPREHENSIVE STRUCTURAL STUDY OF PRE-AND POST-HEAT TREATED COMPRESSION MOLDED POLYURETHANE SAMPLES OF VARYING COMPOSITION STUDIES BY SCANNING PROBE TECHNIQUES (open access)

COMPREHENSIVE STRUCTURAL STUDY OF PRE-AND POST-HEAT TREATED COMPRESSION MOLDED POLYURETHANE SAMPLES OF VARYING COMPOSITION STUDIES BY SCANNING PROBE TECHNIQUES

Only a limited number of structural studies have been performed on polyurethanes using scanning probe techniques to determine both the microstructure and the corresponding distribution of hard and soft segments within samples. This type of information is needed to better understand the mechanical properties of these materials and to facilitate modeling. In order to address these issues, we have fabricated a series of compression molded segmented poly(ester urethane) samples with hard (HS) to soft segment ratios from 19 to 100%. Samples were examined using scanning probe phase imaging techniques to obtain the topography and corresponding distribution of hard domains before and after heating at 100 C. A number of significant differences were observed between the pre- and post-heat treated samples. Variations in structure and heat-induced morphological changes were directly related to HS content. Fine strand- or fibril-like structures were most prominent in the 23 and 19% HS sample but first appeared at 30% HS. Harder, thicker elongated structures dominated the surface of the 100% HS sample and were seen to a limited extent on all samples, especially after annealing and quenching. The 23% HS sample surface structure depended on quenching rate and time after treatment.
Date: March 1, 2001
Creator: HAWLEY, M.; ORLER, E. & AL, ET
System: The UNT Digital Library
Creased-Plastic Rock Permeameter for Hydrogeology Students (open access)

Creased-Plastic Rock Permeameter for Hydrogeology Students

This article discusses the use of creased-plastic permeameters as an inexpensive way for students to estimate the hydraulic conductivity of local rock aquifers.
Date: March 2001
Creator: Hudak, Paul F.
System: The UNT Digital Library
Debris Transport Characteristics (open access)

Debris Transport Characteristics

None
Date: March 1, 2001
Creator: Maji, A. K.; Marshall, B.; Rao, D. V.; Letellier, B. & Shaffer, C.
System: The UNT Digital Library
DETAILED ANALYSIS OF THE SECOND ZEUS CRITICAL EXPERIMENT WITH MCNP (open access)

DETAILED ANALYSIS OF THE SECOND ZEUS CRITICAL EXPERIMENT WITH MCNP

None
Date: March 1, 2001
Creator: MOSTELLER, R. & JAEGERS, P.
System: The UNT Digital Library
DYNAMIC DEFORMATION AND DAMAGE IN CAST GAMMA-TiAl DURING TYALOR CYLINDER IMPACT: EXPERIMENTS AND MODEL VALIDATION (open access)

DYNAMIC DEFORMATION AND DAMAGE IN CAST GAMMA-TiAl DURING TYALOR CYLINDER IMPACT: EXPERIMENTS AND MODEL VALIDATION

The dynamic deformation, damage evolution, and cracking in two cast gamma titanium aluminide alloys has been investigated experimentally and theoretically. The purpose of this study was to create and validate experimentally a finite-element model of the high speed impact of a cylindrical {gamma}-TiAl projectile into a steel block in order to evaluate the accuracy of {gamma} constitutive properties used in FEA simulations. In this paper the damage evolution, cracking, and validation of the constitutive response of Ti-48-2-2 and WMS cast gamma alloys is discussed. The utility of validating the high-rate impact behavior of engineering aerospace materials using Taylor cylinder impact testing is detailed.
Date: March 1, 2001
Creator: GRAY, G. & AL, ET
System: The UNT Digital Library
Effects of buoyancy on the flowfields of lean premixed turbulentv-flames (open access)

Effects of buoyancy on the flowfields of lean premixed turbulentv-flames

Open laboratory turbulent flames used for investigating fundament flame turbulence interactions are greatly affected by buoyancy. Though much of our current knowledge is based on observations made in these open flames, the effects of buoyancy are usually not included in data interpretation, numerical analysis or theories. This inconsistency remains an obstacle to merging experimental observations and theoretical predictions. To better understanding the effects of buoyancy, our research focuses on steady lean premixed flames propagating in fully developed turbulence. We hypothesize that the most significant role of buoyancy forces on these flames is to influence their flowfields through a coupling with mean and fluctuating pressure fields. Changes in flow pattern alter the mean aerodynamic stretch and in turn affect turbulence fluctuation intensities both upstream and downstream of the flame zone. Consequently, flame stabilization, reaction rates, and turbulent flame processes are all affected. This coupling relates to the elliptical problem that emphasizes the importance of the upstream, wall and downstream boundary conditions in determining all aspects of flame propagation. Therefore, buoyancy has the same significance as other parameters such as flow configuration, flame geometry, means of flame stabilization, flame shape, enclosure size, mixture conditions, and flow conditions.
Date: March 1, 2001
Creator: Cheng, R. K.; Bedat, B.; Yegian, D. T. & Greenberg, P.
System: The UNT Digital Library
Emittance growth for the thermalization of space-charged nonuniformities (open access)

Emittance growth for the thermalization of space-charged nonuniformities

Beams injected into a linear focusing channel typically have some degree of space-charge nonuniformity. In general, injected particle distributions with systematic charge nonuniformities are not equilibria of the focusing channel and launch a broad spectrum of collective modes. These modes can phase-mix and have nonlinear wave-wave interactions which, at high space-charge intensities, results in a relaxation to a more thermal-like distribution characterized by a uniform density profile. This thermalization can transfer self-field energy from the initial space-charge nonuniformity to the local particle temperature, thereby increasing beam phase space area (emittance growth). In this paper, we employ a simple kinetic model of a continuous focusing channel and build on previous work that applied system energy and charge conservation to quantify emittance growth associated with the collective thermalization of an initial azimuthally symmetric, rms matched beam with a radial density profile that is hollowed or peaked. This emittance growth is shown to be surprisingly modest even for high beam intensities with significant radial structure in the initial density profile.
Date: March 1, 2001
Creator: Lund, Steven M.; Barnard, John J. & Lee, Edward P.
System: The UNT Digital Library
An Energy Recovery Electron Linac-on-Proton Ring Collider (open access)

An Energy Recovery Electron Linac-on-Proton Ring Collider

Electron-proton colliders with center of mass energies between 14 GeV and 30 GeV and luminosities at the 10{sup 33} level have been proposed recently as a means for studying hadronic structure [1]. Electron beam polarization appears to be crucial for the majority of experiments. Two accelerator design scenarios have been examined in detail: colliding rings [2] and recirculating linac-on-ring [3]. Although the linac-on-ring scenario is not as well understood as the ring-ring scenario, comparable luminosities appear feasible, while the linac-on-ring option presents a significant advantage with spin manipulations. Rf power and beam dump requirements make the linac-on-ring option viable only if the electron linac recovers the beam energy, a technology demonstrated at Jefferson Lab's IR FEL, with cw current up to 5 mA and beam energy up to 50 MeV [4]. We begin with a brief overview of the Jefferson Lab energy recovery FEL and summarize the benefits of energy recovery. The feasibility of an energy recovery linac-ring collider is investigated and two conceptual point designs are shown. Luminosity projections for the linac-ring scenario based on fundamental limitations are presented. Accelerator physics issues are discussed and we conclude with a list of required R and D for the realization of …
Date: March 1, 2001
Creator: Merminga, L.; Krafft, G. & Lebedev, V.
System: The UNT Digital Library
Equilibrium and Nonequilibrium Foundations of Free Energy Computational Methods (open access)

Equilibrium and Nonequilibrium Foundations of Free Energy Computational Methods

Statistical mechanics provides a rigorous framework for the numerical estimation of free energy differences in complex systems such as biomolecules. This paper presents a brief review of the statistical mechanical identities underlying a number of techniques for computing free energy differences. Both equilibrium and nonequilibrium methods are covered.
Date: March 1, 2001
Creator: Jarzynski, C.
System: The UNT Digital Library
ESTIMATION OF RELATIVISTIC ACCRETION DISK PARAMETERS FROM IRON LINE EMISSION (open access)

ESTIMATION OF RELATIVISTIC ACCRETION DISK PARAMETERS FROM IRON LINE EMISSION

The observed iron K{alpha} fluorescence lines in Seyfert I galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the emission. Here we present an analysis of the geometrical and kinematic properties of the disk based on the extreme frequency shifts of a line profile as determined by measurable flux in both the red and blue wings. The edges of the line are insensitive to the distribution of the X-ray flux over the disk, and hence provide a robust alternative to profile fitting of disk parameters. Our approach yields new, strong bounds on the inclination angle of the disk and the location of the emitting region. We apply our method to interpret observational data from MCG-6-30-15 and find that the commonly assumed inclination 30{degree} for the accretion disk in MCG-6-30-15 is inconsistent with the position of the blue edge of the line at a 3{sigma} level. A thick turbulent disk model or the presence of highly ionized iron may reconcile the bounds on inclination from the line edges with the full line profile fits based on simple, geometrically thin disk models. The bounds on the innermost radius of disk emission indicate that the …
Date: March 1, 2001
Creator: PARIEV, V.; BROMLEY, B. & MILLER, W.
System: The UNT Digital Library