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Formation of inner-shell autoionizing CO+ states below the CO++ threshold (open access)

Formation of inner-shell autoionizing CO+ states below the CO++ threshold

We report a kinematically complete experiment on the production of CO{sup +} autoionizing states following photoionization of carbon monoxide below its vertical double ionization threshold. Momentum imaging spectroscopy is used to measure the energies and body-frame angular distributions of both photo- and autoionization electrons, as well as the kinetic energy release (KER) of the atomic ions. This data, in combination with ab initio theoretical calculations, provides insight into the nature of the cation states produced and their subsequent dissociation into autoionizing atomic (O*) fragments.
Date: December 27, 2009
Creator: Osipov, Timur; Weber, Thorsten; Rescigno, Thomas N; Lee, Sun; Orel, Ann; Schoffler, Markus et al.
System: The UNT Digital Library
Cryogenic Field Measurement of Pr2Fe14B Undulator and Performance Enhancement Options at the NSLS-II (open access)

Cryogenic Field Measurement of Pr2Fe14B Undulator and Performance Enhancement Options at the NSLS-II

Short period (14.5mm) hybrid undulator arrays composed of Praseodymium Iron Boron (Pr{sub 2}Fe{sub 14}B) magnets (CR53, NEOMAX, Inc.) and vanadium permendur poles have been fabricated at Brookhaven National Laboratory. Unlike Neodymium Iron Boron (Nd{sub 2}Fe{sub 14}B) magnets which exhibit spin reorientation at temperatures below 150K, PrFeB arrays monotonically increase performance with lower operating temperature. It opens up the posibility for use in operating a cryo-permanent magnet undulator (CPMU) in the range of 40K to 60K where very efficient cryocoolers are available. Magnetic flux density profiles were measured at various temperature ranges from room temperature down to liquid helium (LHe) using the Vertical Testing Facility (VTF) at the National Snchrotron Light Source-II (NSLS-II). Temperature variations of phase error have been characterized. In addition, we examined the use of textured Dysprosium (Dy) poles to replace permendur poles to obtain further improvement in performance.
Date: September 27, 2009
Creator: Tanabe, T.; Chubar, O.; Harder, David A.; Lehecka, Michael; Rank, James; Rakowsky, George et al.
System: The UNT Digital Library
Responsivity of Diamond X-ray Photodiodes Calibrated at NSLS (open access)

Responsivity of Diamond X-ray Photodiodes Calibrated at NSLS

Single crystal, high purity synthetic diamond is used as photoabsorption and carrier transport medium in x-ray photodiodes. While the thermal / mechanical robustness and high x-ray transmission of diamond make such devices attractive for synchrotron instrumentation, state-of-the-art quality material and electrical interfaces further make such detectors feasible. The present work develops methodology for attaining calculable responsivity (photocurrent yield) over a wide range of photon energies (0.2 to 28 keV) to within 5% accuracy. These methods achieve linear response for up to 0.2 W absorbed x-ray power and response time as low as 1 ns. Details of contact formation / robustness and bias configuration are explored.
Date: September 27, 2009
Creator: Keister,J.W.; Smedley, J.; Muller, E. M. & Bohon, J.
System: The UNT Digital Library
Heinz Heinemann.  The Berkeley Years  (1978-1993) (open access)

Heinz Heinemann. The Berkeley Years (1978-1993)

Heinz Heineman came to Berkeley in 1978 and stayed there for 15 years. This was the time of the energy crisis and we did not have anybody like him who had such a tremendous industrial experience with oil and coal conversion technology and science. He was interested in the conversion of coal to gaseous molecules and our studies with model catalysts appealed to him and attracted him. In a way, Heinz Heineman was bigger than life, since he played such a seminal role in the history of American catalysis science.
Date: August 27, 2009
Creator: Coble, Inger M.
System: The UNT Digital Library
HER2 signaling pathway activation and response of breast cancer cells to HER2-targeting agents is dependent strongly on the 3D microenvironment (open access)

HER2 signaling pathway activation and response of breast cancer cells to HER2-targeting agents is dependent strongly on the 3D microenvironment

Development of effective and durable breast cancer treatment strategies requires a mechanistic understanding of the influence of the microenvironment on response. Previous work has shown that cellular signaling pathways and cell morphology are dramatically influenced by three-dimensional (3D) cultures as opposed to traditional two-dimensional (2D) monolayers. Here, we compared 2D and 3D culture models to determine the impact of 3D architecture and extracellular matrix (ECM) on HER2 signaling and on the response of HER2-amplified breast cancer cell lines to the HER2-targeting agents Trastuzumab, Pertuzumab and Lapatinib. We show that the response of the HER2-amplified AU565, SKBR3 and HCC1569 cells to these anti-HER2 agents was highly dependent on whether the cells were cultured in 2D monolayer or 3D laminin-rich ECM gels. Inhibition of {beta}1 integrin, a major cell-ECM receptor subunit, significantly increased the sensitivity of the HER2-amplified breast cancer cell lines to the humanized monoclonal antibodies Trastuzumab and Pertuzumab when grown in a 3D environment. Finally, in the absence of inhibitors, 3D cultures had substantial impact on HER2 downstream signaling and induced a switch between PI3K-AKT- and RAS-MAPKpathway activation in all cell lines studied, including cells lacking HER2 amplification and overexpression. Our data provide direct evidence that breast cancer cells are …
Date: July 27, 2009
Creator: Weigelt, Britta; Lo, Alvin T; Park, Catherine C; Gray, Joe W & Bissell, Mina J
System: The UNT Digital Library
Inhibiting Vimentin or beta 1-integrin Reverts Prostate Tumor Cells in IrECM and Reduces Tumor Growth (open access)

Inhibiting Vimentin or beta 1-integrin Reverts Prostate Tumor Cells in IrECM and Reduces Tumor Growth

Prostate epithelial cells grown embedded in laminin-rich extracellular matrix (lrECM) undergo morphological changes that closely resemble their architecture in vivo. In this study, growth characteristics of three human prostate epithelial sublines derived from the same cellular lineage, but displaying different tumorigenic and metastatic properties in vivo, were assessed in three-dimensional (3D) lrECM gels. M12, a highly tumorigenic and metastatic subline, was derived from the parental prostate epithelial P69 cell line by selection in nude mice and found to contain a deletion of 19p-q13.1. The stable reintroduction of an intact human chromosome 19 into M12 resulted in a poorly tumorigenic subline, designated F6. When embedded in lrECM gels, the nontumorigenic P69 line produced acini with clearly defined lumena. Immunostaining with antibodies to {beta}-catenin, E-cadherin or {alpha}6-, {beta}4- and {beta}1-integrins showed polarization typical of glandular epithelium. In contrast, the metastatic M12 subline produced highly disorganized cells with no evidence of polarization. The F6 subline reverted to acini-like structures exhibiting basal polarity marked with integrins. Reducing either vimentin levels via siRNA interference or {beta}1-integrin expression by the addition of the blocking antibody, AIIB2, reorganized the M12 subline into forming polarized acini. The loss of vimentin significantly reduced M12-Vim tumor growth when assessed by …
Date: July 27, 2009
Creator: Zhang, Xueping; Fournier, Marcia V.; Ware, Joy L.; Bissell, Mina J. & Zehner, Zendra E.
System: The UNT Digital Library
Muon Production in Relativistic Cosmic-Ray Interactions (open access)

Muon Production in Relativistic Cosmic-Ray Interactions

Cosmic-rays with energies up to 3x1020 eV have been observed. The nuclear composition of these cosmic rays is unknown but if the incident nuclei are protons then the corresponding center of mass energy is sqrt snn = 700 TeV. High energy muons can be used to probe the composition of these incident nuclei. The energy spectra of high-energy (> 1 TeV) cosmic ray induced muons have been measured with deep underground or under-ice detectors. These muons come from pion and kaon decays and from charm production in the atmosphere. Terrestrial experiments are most sensitive to far-forward muons so the production rates aresensitive to high-x partons in the incident nucleus and low-x partons in the nitrogen/oxygen targets. Muon measurements can complement the central-particle data collected at colliders.This paper will review muon production data and discuss some non-perturbative (soft) models that have been used to interpret the data. I will show measurements of TeV muon transverse momentum (pT) spectra in cosmic-ray air showers fromMACRO, and describe how the IceCube neutrino observatory and the proposed Km3Net detector will extend these measurements to a higher pT region where perturbative QCD should apply. With a 1 km2 surface area, the full IceCube detector should observe …
Date: July 27, 2009
Creator: Klein, Spencer
System: The UNT Digital Library
Switchgrass (Panicum virgatum) possesses a divergent family of cinnamoyl CoA reductases with distinct biochemical properties (open access)

Switchgrass (Panicum virgatum) possesses a divergent family of cinnamoyl CoA reductases with distinct biochemical properties

Article on switchgrass (Panicum virgatum) possessing a divergent family of cinnamoyl CoA reductases with distinct biochemical properties.
Date: July 27, 2009
Creator: Escamilla-Treviño, Luis; Shen, Hui; Uppalapati, Srinivasa Rao; Ray, Tui; Tang, Yuhong; Hernandez, Timothy et al.
System: The UNT Digital Library
Theoretical Concepts for Ultra-Relativistic Heavy Ion Collisions (open access)

Theoretical Concepts for Ultra-Relativistic Heavy Ion Collisions

Various forms of matter may be produced in ultra-relativistic heavy ion collisions. These are the Quark GluonPlasma, the Color Glass Condensate , the Glasma and Quarkyoninc Matter. A novel effect that may beassociated with topological charge fluctuations is the Chiral Magnetic Effect. I explain these concepts andexplain how they may be seen in ultra-relatvistic heavy ion collisions
Date: July 27, 2009
Creator: McLerran, L.
System: The UNT Digital Library
Glass Formulation for the Hanford Tank Waste Treatment and Immobilization Plant (Wtp) (open access)

Glass Formulation for the Hanford Tank Waste Treatment and Immobilization Plant (Wtp)

A computational method for formulating Hanford HLW glasses was developed that is based on empirical glass composition-property models, accounts for all associated uncertainties, and can be solved in Excel{sup R} in minutes. Calculations for all waste form processing and compliance requirements included. Limited experimental validation performed.
Date: May 27, 2009
Creator: Kruger, A. A.; Vienna, J. D.; Kim, D. S. & Jain, V.
System: The UNT Digital Library
NEPTUNIUM OXIDE PROCESSING (open access)

NEPTUNIUM OXIDE PROCESSING

The Savannah River Site's HB-Line Facility completed a campaign in which fifty nine cans of neptunium oxide were produced and shipped to the Idaho National Laboratory in the 9975 shipping container. The neptunium campaign was divided into two parts: Part 1 which consisted of oxide made from H-Canyon neptunium solution which did not require any processing prior to conversion into an oxide, and Part 2 which consisted of oxide made from additional H-Canyon neptunium solutions which required processing to purify the solution prior to conversion into an oxide. The neptunium was received as a nitrate solution and converted to oxide through ion-exchange column extraction, precipitation, and calcination. Numerous processing challenges were encountered in order make a final neptunium oxide product that could be shipped in a 9975 shipping container. Among the challenges overcome was the issue of scale: translating lab scale production into full facility production. The balance between processing efficiency and product quality assurance was addressed during this campaign. Lessons learned from these challenges are applicable to other processing projects.
Date: May 27, 2009
Creator: Jordan, J; Watkins, R & Hensel, S
System: The UNT Digital Library
Polarized gun and ERL R and D for eRHIC (open access)

Polarized gun and ERL R and D for eRHIC

At Jefferson Laboratory charge density and charge lifetime during electron beam delivery are over 2 x 10{sup 5} C/cm{sup 2} and 200 C, respectively. A 200 C charge lifetime at 2 mA corresponds to 10{sup 5} seconds. In a more recent result, charge lifetimes of about an order of magnitude larger were achieved by a load-lock gun with a larger cathode area.
Date: May 27, 2009
Creator: Ben-Zvi, Ilan
System: The UNT Digital Library
RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH (open access)

RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH

A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically …
Date: May 27, 2009
Creator: Maxwell, S. & Jones, V.
System: The UNT Digital Library
Results of Compact Stellarator Engineering Trade Studies (open access)

Results of Compact Stellarator Engineering Trade Studies

number of technical requirements and performance criteria can drive stellarator costs, e.g., tight tolerances, accurate coil positioning, low aspect ratio (compactness), choice of assembly strategy, metrology, and complexity of the stellarator coil geometry. With the completion of a seven-year design and construction effort of the National Compact Stellarator Experiment (NCSX) it is useful to interject the NCSX experience along with the collective experiences of the NCSX stellarator community to improving the stellarator configuration. Can improvements in maintenance be achieved by altering the stellarator magnet configuration with changes in the coil shape or with the combination of trim coils? Can a mechanical configuration be identified that incorporates a partial set of shaped fixed stellarator coils along with some removable coil set to enhance the overall machine maintenance? Are there other approaches that will simplify the concepts, improve access for maintenance, reduce overall cost and improve the reliability of a stellarator based power plant? Using ARIES-CS and NCSX as reference cases, alternative approaches have been studied and developed to show how these modifications would favorably impact the stellarator power plant and experimental projects. The current status of the alternate stellarator configurations being developed will be described and a comparison made to the …
Date: May 27, 2009
Creator: Brown, Tom; Bromberg, L. & Cole, M.
System: The UNT Digital Library
VALIDATION OF ANALYTICAL METHODS AND INSTRUMENTATION FOR BERYLLIUM MEASUREMENT: REVIEW AND SUMMARY OF AVAILABLE GUIDES, PROCEDURES, AND PROTOCOLS (open access)

VALIDATION OF ANALYTICAL METHODS AND INSTRUMENTATION FOR BERYLLIUM MEASUREMENT: REVIEW AND SUMMARY OF AVAILABLE GUIDES, PROCEDURES, AND PROTOCOLS

Method validation is the process of evaluating whether an analytical method is acceptable for its intended purpose. For pharmaceutical methods, guidelines from the United States Pharmacopeia (USP), International Conference on Harmonisation (ICH), and the United States Food and Drug Administration (USFDA) provide a framework for performing such valications. In general, methods for regulatory compliance must include studies on specificity, linearity, accuracy, precision, range, detection limit, quantitation limit, and robustness. Elements of these guidelines are readily adapted to the issue of validation for beryllium sampling and analysis. This document provides a listing of available sources which can be used to validate analytical methods and/or instrumentation for beryllium determination. A literature review was conducted of available standard methods and publications used for method validation and/or quality control. A comprehensive listing of the articles, papers and books reviewed is given in the Appendix. Available validation documents and guides are listed therein; each has a brief description of application and use. In the referenced sources, there are varying approches to validation and varying descriptions of the valication process at different stages in method development. This discussion focuses on valication and verification of fully developed methods and instrumentation that have been offered up for use …
Date: May 27, 2009
Creator: Ekechukwu, A
System: The UNT Digital Library
WASTE DISPOSITION ON THE HANFORD PLATEAU REMEDIATION CONTRACT (open access)

WASTE DISPOSITION ON THE HANFORD PLATEAU REMEDIATION CONTRACT

None
Date: May 27, 2009
Creator: Moak, Don J.; Triner, Glen C. & Waters, Mike S.
System: The UNT Digital Library
California Wintertime Precipitation in Regional and Global Climate Models (open access)

California Wintertime Precipitation in Regional and Global Climate Models

In this paper, wintertime precipitation from a variety of observational datasets, regional climate models (RCMs), and general circulation models (GCMs) is averaged over the state of California (CA) and compared. Several averaging methodologies are considered and all are found to give similar values when model grid spacing is less than 3{sup o}. This suggests that CA is a reasonable size for regional intercomparisons using modern GCMs. Results show that reanalysis-forced RCMs tend to significantly overpredict CA precipitation. This appears to be due mainly to overprediction of extreme events; RCM precipitation frequency is generally underpredicted. Overprediction is also reflected in wintertime precipitation variability, which tends to be too high for RCMs on both daily and interannual scales. Wintertime precipitation in most (but not all) GCMs is underestimated. This is in contrast to previous studies based on global blended gauge/satellite observations which are shown here to underestimate precipitation relative to higher-resolution gauge-only datasets. Several GCMs provide reasonable daily precipitation distributions, a trait which doesn't seem tied to model resolution. GCM daily and interannual variability is generally underpredicted.
Date: April 27, 2009
Creator: Caldwell, P M
System: The UNT Digital Library
LITERATURE SURVEY OF GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS (open access)

LITERATURE SURVEY OF GASEOUS HYDROGEN EFFECTS ON THE MECHANICAL PROPERTIES OF CARBON AND LOW ALLOY STEELS

Literature survey has been performed for a compendium of mechanical properties of carbon and low alloy steels following hydrogen exposure. The property sets include yield strength, ultimate tensile strength, uniform elongation, reduction of area, threshold stress intensity factor, fracture toughness, and fatigue crack growth. These properties are drawn from literature sources under a variety of test methods and conditions. However, the collection of literature data is by no means complete, but the diversity of data and dependency of results in test method is sufficient to warrant a design and implementation of a thorough test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).
Date: April 27, 2009
Creator: Lam, P; Andrew Duncan, A; Robert Sindelar, R & Thad Adams, T
System: The UNT Digital Library
Resonant Kicker System Development at SLAC (open access)

Resonant Kicker System Development at SLAC

The design and installation of the Linear Coherent Light Source [1] at SLAC National Accelerator Laboratory has included the development of a kicker system for selective beam bunch dumping. The kicker is based on an LC resonant topology formed by the 50 uF energy storage capacitor and the 64 uH air core magnet load which has a sinusoidal pulse period of 400us. The maximum magnet current is 500 A. The circuit is weakly damped, allowing most of the magnet energy to be recovered in the energy storage capacitor. The kicker runs at a repetition rate of 120Hz. A PLC-based control system provides remote control and monitoring of the kicker via EPICS protocol. Fast timing and interlock signals are converted by discrete peak-detect and sample-hold circuits into DC signals that can be processed by the PLC. The design and experimental characterization of the system are presented.
Date: April 27, 2009
Creator: Beukers, Tony; Krzaszczak, John; Larrus, Marc & Lira, Antonio de
System: The UNT Digital Library
Suzaku Observations of PSR B1259-63: A New Manifestation of Relativistic Pulsar Wind (open access)

Suzaku Observations of PSR B1259-63: A New Manifestation of Relativistic Pulsar Wind

We observed PSR B1259-63, a young non-accreting pulsar orbiting around a Be star SS 2883, eight times with the Suzaku satellite from July to September 2007, to characterize the X-ray emission arising from the interaction between a pulsar relativistic wind and Be star outflows. The X-ray spectra showed a featureless continuum in 0.6-10 keV, modeled by a power law with a wide range of photon index 1.3-1.8. When combined with the Suzaku PIN detector which allowed spectral analysis in the hard 15-50 keV band, X-ray spectra do show a break at {approx} 5 keV in a certain epoch. Regarding the PSR B1259-63 system as a compactified pulsar wind nebula, in which e{sup {+-}} pairs are assumed to be accelerated at the inner shock front of the pulsar wind, we attribute the X-ray spectral break to the low-energy cutoff of the synchrotron radiation associated with the Lorentz factor of the relativistic pulsar wind {gamma}{sub 1} {approx} 4 x 10{sup 5}. Our result indicates that Comptonization of stellar photons by the unshocked pulsar wind will be accessible (or tightly constrained) by observations with the Fermi Gamma-ray Space Telescope during the next periastron passage. The PSR B1259-63 system allows us to probe the …
Date: April 27, 2009
Creator: Uchiyama, Yasunobu; Tanaka, Takaaki; Takahashi, Tadayuki; Mori, Koji & Nakazawa, Kazuhiro
System: The UNT Digital Library
THERMAL EVALUATION OF DRUM TYPE RADIOACTIVE MATERIAL PACKAGING ARRAYS IN STORAGE (open access)

THERMAL EVALUATION OF DRUM TYPE RADIOACTIVE MATERIAL PACKAGING ARRAYS IN STORAGE

Drum type packages are routinely used to transport radioactive material (RAM) in the U.S. Department of Energy (DOE) complex. These packages are designed to meet the federal regulations described in 10 CFR 71.[1] In recent years, there has been a greater need to use these packagings to store the excess fissile material, especially plutonium for long term storage. While the design requirements for safe transportation of these packagings are well defined, the requirements for safe long term storage are not well established. Since the RAM contents in the packagings produce decay heat, it is important that they are stored carefully to prevent overheating of the containment vessel (CV) seals to prevent any leakage and the impact limiter to maintain the package structural integrity. This paper analyzes different storage arrays for a typical 9977 packaging for thermal considerations and makes recommendations for their safe storage under normal operating conditions.
Date: April 27, 2009
Creator: Gupta, N
System: The UNT Digital Library
Surfactant-Assisted Hydrothermal Synthesis of Single Phase Pyrite FeS2 Nanocrystals (open access)

Surfactant-Assisted Hydrothermal Synthesis of Single Phase Pyrite FeS2 Nanocrystals

Iron pyrite nanocrystals with high purity have been synthesized through a surfactant-assisted hydrothermal reaction under optimum pH value. These pyrite nanocrystals represent a new group of well-defined nanoscale structures for high-performance photovoltaic solar cells based on non-toxic and earth abundant materials.
Date: March 27, 2009
Creator: Wadia, Cyrus; Wu, Yue; Gul, Sheraz; Volkman, Steven; Guo, Jinghua & Alivisatos, Paul
System: The UNT Digital Library
Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions (open access)

Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions

We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.
Date: February 27, 2009
Creator: Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B. & Salmeron, Miquel
System: The UNT Digital Library
The Response of Long-Span Bridges to Low Frequency, Near-Fault Earthquake Ground Motions (open access)

The Response of Long-Span Bridges to Low Frequency, Near-Fault Earthquake Ground Motions

Historical seismic hazard characterizations did not include earthquake ground motion waveforms at frequencies below approximately 0.2 Hz (5 seconds period). This resulted from limitations in early strong motion instrumentation and signal processing techniques, a lack of measurements in the near-field of major earthquakes and therefore no observational awareness, and a delayed understanding in the engineering community of the potential significance of these types of motions. In recent years, there is a growing recognition of the relevance of near-fault, low frequency motions, particularly for long-period structures such as large bridges. This paper describes a computationally based study of the effects of low frequency (long-period) near-fault motions on long-span bridge response. The importance of inclusion of these types of motions for long span cable supported bridges is demonstrated using actual measured broad-band, near-fault motions from large earthquakes.
Date: February 27, 2009
Creator: McCallen, David; Astaneh-Asl, A.; Larsen, S.C. & Hutchings, Larry
System: The UNT Digital Library