First Principals and Classical Molecular Dynamics Simulations of Solvated Benzene (open access)

First Principals and Classical Molecular Dynamics Simulations of Solvated Benzene

We have performed extensive ab initio and classical MD simulations of benzene in water in order to examine the unique solvation structures that are formed. Qualitative differences between classical and ab initio MD simulations are found and the importance of various technical simulation parameters is examined. Our comparison indicates that non-polarizable classical models are not capable of describing the solute-water interface correctly if local interactions become energetically comparable to water hydrogen bonds. In addition, a comparison is made between a rigid water model and fully flexible water within ab initio MD simulations which shows that both models agree qualitatively for this challenging system.
Date: September 11, 2007
Creator: Allesch, M; Lightstone, F; Schwegler, E & Galli, G
Object Type: Article
System: The UNT Digital Library
Development of a Fluxless Flip Chip Bonding Process for Optical Military Electronics (open access)

Development of a Fluxless Flip Chip Bonding Process for Optical Military Electronics

As military electronics tend to become lighter, smaller, thinner, and lower cost, the use of flip chip technology is becoming more common place to meet system requirements, yet survive environments. This paper explores the development of an optical flip chip application and details the selection/qualification of the substrate. The selected assembly consists of a procured 1x12 Vertical Cavity Surface Emitting Laser (VCSEL) die, having 80um diameter eutectic AuSn solder bumps at 250um pitch and flip chip bonded to a .006” thick 99.6% alumina substrate with .006” diameter thru holes and metallized with 500Å WTi, under minimum 2.0-3.0μm (80-120μ”) thin film deposited Au. An 8 run, 3 factor, 2 level Full Factorial Design of Experiments (DOE) was completed on procured detector arrays and procured ceramic substrates using the Suss Microtec FC150. The optimum settings for the peak temperature, peak time and final die z-height were selected using the ANOVA results and interaction plots. Additional studies were completed to qualify in-house produced substrates. An epoxy glob-top encapsulant was selected to dissipate stress on the flip chip solder joints and to enhance thermal shock performance.
Date: November 11, 2007
Creator: Girardi, Michael
Object Type: Article
System: The UNT Digital Library
Field Evaluation of Low-E Storm Windows (open access)

Field Evaluation of Low-E Storm Windows

A field evaluation comparing the performance of low emittance (low-e) storm windows with both standard clear storm windows and no storm windows was performed in a cold climate. Six homes with single-pane windows were monitored over the period of one heating season. The homes were monitored with no storm windows and with new storm windows. The storm windows installed on four of the six homes included a hard coat, pyrolitic, low-e coating while the storm windows for the other two homeshad traditional clear glass. Overall heating load reduction due to the storm windows was 13percent with the clear glass and 21percent with the low-e windows. Simple paybacks for the addition of the storm windows were 10 years for the clear glass and 4.5 years forthe low-e storm windows.
Date: July 11, 2007
Creator: Drumheller, S. Craig; Kohler, Christian & Minen, Stefanie
Object Type: Article
System: The UNT Digital Library
Technical and Political Assessment of Peaceful Nuclear Power Program Prospects in North Africa and the Middle East (open access)

Technical and Political Assessment of Peaceful Nuclear Power Program Prospects in North Africa and the Middle East

An exceptional number of Middle Eastern and North African nations have recently expressed interest in developing nuclear energy for peaceful purposes. Many of these countries have explored nuclear research in limited ways in the past, but the current focused interest and application of resources towards developing nuclear-generated electricity and nuclear-powered desalination plants is unprecedented. Consequently, questions arise in response to this emerging trend: What instigated this interest? To what end(s) will a nuclear program be applied? Does the country have adequate technical, political, legislative, nonproliferation, and safety infrastructure required for the capability desired? If so, what are the next steps for a country in preparation for a future nuclear program? And if not, what collaboration efforts are possible with the United States or others? This report provides information on the capabilities and interests of 13 countries in the region in nuclear energy programs in light of safety, nonproliferation and security concerns. It also provides information useful for determining potential for offering technical collaboration, financial aid, and/or political support.
Date: September 11, 2007
Creator: Windsor, Lindsay K. & Kessler, Carol E.
Object Type: Report
System: The UNT Digital Library
Stopping the growth of particles to silica-supported mono-nuclear Ru hydride surface species by tuning silica with surface silanes (open access)

Stopping the growth of particles to silica-supported mono-nuclear Ru hydride surface species by tuning silica with surface silanes

Tuning silica by replacing surface silanols with silanes allows chemical grafting of Ru(COD)(COT) through a covalent Ru-Si bond, as evidenced by elemental analysis, IR spectroscopy and EXAFS. Treatment of these surface species under H2 at 300 oC yields a mononuclear Ru hydride species, without any sintering of the metal according to TEM and EXAFS analyses. This supported system displays catalytic properties different from those of supported Ru particles (2 nm), selectively hydrogenating olefins over aromatics.
Date: July 11, 2007
Creator: Berthoud, Romain; Fenet, Bernard; Lukens, Wayne; Pelzer, Katrin; Basset, Jean-Marie; Candy, Jean-Pierre et al.
Object Type: Article
System: The UNT Digital Library
Valence band anticrossing in GaBixAs1-x (open access)

Valence band anticrossing in GaBixAs1-x

The optical properties of GaBixAs1-x (0.04< x< 0.08) grown by molecular beam epitaxy have been studied by photomodulated reflectance spectroscopy. The alloys exhibit a strong reduction in the bandgap as well as an increase in the spin-orbit splitting energy with increasing Bi concentration. These observations are explained by a valence band anticrossing model, which shows that a restructuring of the valence band occurs as the result of an anticrossing interaction between the extended states of the GaAs valence band and the resonant T2 states of the Bi atoms.
Date: July 11, 2007
Creator: Alberi, K.; Dubon, O. D.; Walukiewicz, W.; Yu, K. M.; Bertulis, K. & Krotkus, A.
Object Type: Article
System: The UNT Digital Library
IMPROVED WIND AND TURBULENCE MEASUREMENTS USING A LOW-COST 3-D SONIC ANEMOMETER AT A LOW-WIND SITE (open access)

IMPROVED WIND AND TURBULENCE MEASUREMENTS USING A LOW-COST 3-D SONIC ANEMOMETER AT A LOW-WIND SITE

A year of data from sonic anemometer and mechanical wind sensors was analyzed and compared at a low-wind site. Results indicate that 15-minute average and peak 1-second wind speeds (u) from the sonic agree well with data derived from a co-located cup anemometer over a wide range of speeds. Wind direction data derived from the sonic also agree closely with those from a wind vane except for very low wind speeds. Values of standard deviation of longitudinal wind speed ({sigma}{sub u}) and wind direction fluctuations ({delta}{sub {theta}}) from the sonic and mechanical sensors agree well for times with u > 2 ms{sup -1} but show significant differences with lower u values. The most significant differences are associated with the standard deviation of vertical wind fluctuations ({sigma}{sub w}): the co-located vertical propeller anemometer yields values increasingly less than those measured by the sonic anemometer as u decreases from 2.5 approaching 0 ms{sup -1}. The combination of u over-estimation and under-estimation of {sigma}{sub w} from the mechanical sensors at low wind speeds causes considerable under-estimation of the standard deviation of vertical wind angle fluctuations ({sigma}{sub {phi}}), an indicator of vertical dispersion. Calculations of {sigma}{sub {phi}} from sonic anemometer measurements are typically 5{sup …
Date: May 11, 2007
Creator: Bowen, B
Object Type: Report
System: The UNT Digital Library
Promotion of Homologous Recombination and Genomic Stability byRAD51AP1 via RAD51 Recombinase Enhancement (open access)

Promotion of Homologous Recombination and Genomic Stability byRAD51AP1 via RAD51 Recombinase Enhancement

Homologous recombination (HR) repairs chromosome damage and is indispensable for tumor suppression in humans. RAD51 mediates the DNA strand pairing step in HR. RAD51AP1 (RAD51 Associated Protein 1) is a RAD51-interacting protein whose function has remained elusive. Knockdown of RAD51AP1 in human cells by RNA interference engenders sensitivity to different types of genotoxic stress. Moreover, RAD51AP1-depleted cells are impaired for the recombinational repair of a DNA double-strand break and exhibit chromatid breaks both spontaneously and upon DNA damaging treatment. Purified RAD51AP1 binds dsDNA and RAD51, and it greatly stimulates the RAD51-mediated D-loop reaction. Biochemical and cytological results show that RAD51AP1 functions at a step subsequent to the assembly of the RAD51-ssDNA nucleoprotein filament. Our findings provide the first evidence that RAD51AP1 helps maintain genomic integrity via RAD51 recombinase enhancement.
Date: April 11, 2007
Creator: Wiese, Claudia; Dray, Eloise; Groesser, Torsten; San Filippo,Joseph; Shi, Idina; Collins, David W. et al.
Object Type: Article
System: The UNT Digital Library
Microscopic Calculations of 240Pu Fission (open access)

Microscopic Calculations of 240Pu Fission

Hartree-Fock-Bogoliubov calculations have been performed with the Gogny finite-range effective interaction for {sup 240}Pu out to scission, using a new code developed at LLNL. A first set of calculations was performed with constrained quadrupole moment along the path of most probable fission, assuming axial symmetry but allowing for the spontaneous breaking of reflection symmetry of the nucleus. At a quadrupole moment of 345 b, the nucleus was found to spontaneously scission into two fragments. A second set of calculations, with all nuclear moments up to hexadecapole constrained, was performed to approach the scission configuration in a controlled manner. Calculated energies, moments, and representative plots of the total nuclear density are shown. The present calculations serve as a proof-of-principle, a blueprint, and starting-point solutions for a planned series of more comprehensive calculations to map out a large set of scission configurations, and the associated fission-fragment properties.
Date: September 11, 2007
Creator: Younes, W & Gogny, D
Object Type: Report
System: The UNT Digital Library
CHARACTERIZATION OF THERMALLY DAMAGED LX-17 (open access)

CHARACTERIZATION OF THERMALLY DAMAGED LX-17

Thermal damage was applied to LX-17 at 190 C for several hours. The damaged LX-17 samples, after cooled down to room temperature, were characterized for their material properties (density, porosity, permeability, moduli), safety, and performance. Weight losses upon thermal exposure were insignificant (< 0.1% wt.). The damaged LX-17 samples expanded, resulting in a bulk density reduction of 4.3%. Subsequent detonation measurements (cylinder tests) were conducted on the thermally-damaged LX-17 samples. The results showed that the fractions of damaged LX-17 reacted were slightly lower than those of pristine LX-17. The thermally damaged LX-17 had a detonation velocity of 7.315 mm/{micro}s, lower than that (7.638 mm/{micro}s) of pristine LX-17. Detonation energy density for the damaged LX-17 was 5.08 kJ/cm{sup 3}, about 9.0% lower than the detonation energy density of 5.50 kJ/cm{sup 3} for the pristine LX-17. The break-out curves showed reaction zone lengths for pristine LX-17 and damaged LX-17 were similar but the damaged samples had ragged detonation fronts.
Date: July 11, 2007
Creator: Hsu, P C
Object Type: Article
System: The UNT Digital Library
SAVANNAH RIVER SITE CAPABILITIES FOR CONDUCTING INGESTION PATHWAY CONSEQUENCE ASSESSMENTS FOR EMERGENCY RESPONSE (open access)

SAVANNAH RIVER SITE CAPABILITIES FOR CONDUCTING INGESTION PATHWAY CONSEQUENCE ASSESSMENTS FOR EMERGENCY RESPONSE

Potential airborne releases of radioactivity from facilities operated for the U. S. Department of Energy at the Savannah River Site could pose significant consequences to the public through the ingestion pathway. The Savannah River National Laboratory has developed a suite of technologies needed to conduct assessments of ingestion dose during emergency response, enabling emergency manager at SRS to develop initial protective action recommendation for state agencies early in the response and to make informed decisions on activation of additional Federal assets that would be needed to support long-term monitoring and assessment activities.
Date: December 11, 2007
Creator: Hunter, C
Object Type: Article
System: The UNT Digital Library
Estimation of Radiation Doses in the Marshall Islands Based on Whole Body Counting of Cesium-137 (137Cs) and Plutonium Urinalysis (open access)

Estimation of Radiation Doses in the Marshall Islands Based on Whole Body Counting of Cesium-137 (137Cs) and Plutonium Urinalysis

Under the auspices of the U.S. Department of Energy (USDOE), researchers from the Lawrence Livermore National Laboratory (LLNL) have recently implemented a series of initiatives to address long-term radiological surveillance needs at former nuclear test sites in the Republic of the Marshall Islands (RMI). The aim of this radiological surveillance monitoring program (RSMP) is to provide timely radiation protection for individuals in the Marshall Islands with respect to two of the most important internally deposited fallout radionuclides-cesium-137 ({sup 137}Cs) and long-lived isotopes 239 and 240 of plutonium ({sup 239+240}Pu) (Robison et al., 1997 and references therein). Therefore, whole-body counting for {sup 137}Cs and a sensitive bioassay for the presence of {sup 239+240}Pu excreted in urine were adopted as the two most applicable in vivo analytical methods to assess radiation doses for individuals in the RMI from internally deposited fallout radionuclides (see Hamilton et al., 2006a-c; Bell et al., 2002). Through 2005, the USDOE has established three permanent whole-body counting facilities in the Marshall Islands: the Enewetak Radiological Laboratory on Enewetak Atoll, the Utrok Whole-Body Counting Facility on Majuro Atoll, and the Rongelap Whole-Body Counting Facility on Rongelap Atoll. These whole-body counting facilities are operated and maintained by trained Marshallese technicians. …
Date: June 11, 2007
Creator: Daniels, J.I.; Hickman, D.P.; Kehl, S.R. & Hamilton, T.F.
Object Type: Report
System: The UNT Digital Library
Response to Comment on "The National Ignition Facility Laser Performance Status" (open access)

Response to Comment on "The National Ignition Facility Laser Performance Status"

We appreciate Stephen Bodner's continuing interest in the performance of the NIF laser system. However, we find it necessary to disagree with the conclusions he reached in his comments [Appl. Opt. 47, XXX (2008)] on 'National Ignition Facility Laser Performance Status' [Appl. Opt. 46, 3276 (2007)]. In fact, repeated and ongoing tests of the NIF beamlines have demonstrated that NIF can be expected not only to meet or exceed its requirements as established in the mid-1990s in the document National Ignition Facility Functional Requirements and Primary Criteria [Revision 1.3, Report NIF-LLNL-93-058 (1994)], but also to have the flexibility that provides for successfully meeting an ever expanding range of mission goals, including those of ignition.
Date: December 11, 2007
Creator: Haynam, C A; Sacks, R A; Moses, E I; Manes, K; Haan, S & Spaeth, M L
Object Type: Article
System: The UNT Digital Library
Remaining Sites Verification Package for the 100-C-9:1 Main Process Sewer Collection Line, Waste Site Reclassification Form 2004-012 (open access)

Remaining Sites Verification Package for the 100-C-9:1 Main Process Sewer Collection Line, Waste Site Reclassification Form 2004-012

The 100-C-9:1 main process sewer pipeline, also known as the twin box culvert, was a dual reinforced process sewer that collected process effluent from the 183-C and 190-C water treatment facilities, discharging at the 132-C-2 Outfall. For remedial action purposes, the 100-C-9:1 waste site was subdivided into northern and southern sections. The 100-C-9:1 subsite has been remediated to achieve the remedial action objectives specified in the Remaining Sites ROD. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: June 11, 2007
Creator: Dittmer, L. M.
Object Type: Report
System: The UNT Digital Library
Uncertainty Detection for NIF Normal Pointing Images (open access)

Uncertainty Detection for NIF Normal Pointing Images

The National Ignition Facility at the Lawrence Livermore National Laboratory when completed in 2009, will deliver 192-beams aligned precisely at the center of the target chamber producing extreme energy densities and pressures. Video images of laser beams along the beam path are used by automatic alignment algorithms to determine the position of the beams for alignment purposes. However, noise and other optical effects may affect the accuracy of the calculated beam location. Realistic estimation of the uncertainty is necessary to assure that the beam is monitored within the clear optical path. When the uncertainty is above a certain threshold the automated alignment operation is suspended and control of the beam is transferred to a human operator. This work describes our effort to quantify the uncertainty of measurement of the most common alignment beam.
Date: September 11, 2007
Creator: Awwal, Abdul A.S.; Law, Clement & Ferguson, S. Walter
Object Type: Article
System: The UNT Digital Library
Results of Chemical Analyses in Support of Yucca Mountain Studies (open access)

Results of Chemical Analyses in Support of Yucca Mountain Studies

Ground water monitoring for the Nye County Early Warning Drilling Program (NCEWDP) was established to monitor underground water sources of the area and to protect communities surrounding the Nevada Test Site (NTS) from potential radionuclide contamination of these water sources. It provides hydrological information pertaining to groundwater flow patterns and recharge issues in the vicinity of Yucca Mountain. The Harry Reid Center for Environmental Studies (HRC) obtained groundwater samples from select NCEWDP wells shown in Figure 1. These samples were analyzed for major cations, major anions, trace elements, rare earth elements, alkalinity, pH and conductivity. These geochemical results can be used to evaluate the degree of interaction between the aquifers sampled, leading to a thorough mapping of the aquifer system. With increased analysis down gradient of the Yucca Mountain area, evaluations can identify viable groundwater flow paths and establish mixing of the groundwater systems. Tracer tests provide insight into groundwater flow characteristics and transport processes of potential contaminants. These tests are important for contaminant migration issues including safe disposal of hazardous and radioactive materials and remediation of potentially released contaminants. At a minimum, two conservative (non-sorbing) tracers with different diffusion coefficients are used for each tracer test. The tracer test …
Date: December 11, 2007
Creator: Daniels, Jeanette
Object Type: Report
System: The UNT Digital Library
Simulation of Biological Flow and Transport in Complex Geometries using Embedded Boundary / Volume-of-Fluid Methods (open access)

Simulation of Biological Flow and Transport in Complex Geometries using Embedded Boundary / Volume-of-Fluid Methods

None
Date: July 11, 2007
Creator: Trebotich, D.
Object Type: Article
System: The UNT Digital Library
A multiplexed reverse transcriptase PCR assay for identification of viral respiratory pathogens at point-of-care (open access)

A multiplexed reverse transcriptase PCR assay for identification of viral respiratory pathogens at point-of-care

We have developed a nucleic acid-based assay that is rapid, sensitive, specific, and can be used for the simultaneous detection of 5 common human respiratory pathogens including influenza A, influenza B, parainfluenza type 1 and 3, respiratory syncytial virus, and adenovirus group B, C, and E. Typically, diagnosis on an un-extracted clinical sample can be provided in less than 3 hours, including sample collection, preparation, and processing, as well as data analysis. Such a multiplexed panel would enable rapid broad-spectrum pathogen testing on nasal swabs, and therefore allow implementation of infection control measures, and timely administration of antiviral therapies. This article presents a summary of the assay performance in terms of sensitivity and specificity. Limits of detection are provided for each targeted respiratory pathogen, and result comparisons are performed on clinical samples, our goal being to compare the sensitivity and specificity of the multiplexed assay to the combination of immunofluorescence and shell vial culture currently implemented at the UCDMC hospital. Overall, the use of the multiplexed RT-PCR assay reduced the rate of false negatives by 4% and reduced the rate of false positives by up to 10%. The assay correctly identified 99.3% of the clinical negatives, 97% of adenovirus, 95% …
Date: April 11, 2007
Creator: Letant, S. E.; Ortiz, J. I.; Tammero, L.; Birch, J. M.; Derlet, R. W.; Cohen, S. et al.
Object Type: Article
System: The UNT Digital Library
Qualification of Automated Low-Field NMR Relaxometry for Quality Control of Polymers in a Production Setting (open access)

Qualification of Automated Low-Field NMR Relaxometry for Quality Control of Polymers in a Production Setting

Implementation of a low field time-domain NMR scanner as a diagnostic tool in the production of new polymer components is described in the context of qualification of a new QA/QC device. A study to determine the optimal experimental parameters was performed and a robotic autosampler was built to enable scanning of multiple pads. Relationships between T{sub 2} values and physical properties of DC745 slabs were investigated, and the appropriate sampling parameters for the production setting were determined. Two versions of a robotic autosampler were built, and for the component described here a fourth radial axis was required in addition to traditional X, Y, and Z movement to eliminate the large variability in T{sub 2} due to inconsistent sample coverage caused by complex rib geometry of the component. Data show that with appropriate choice of experimental conditions of the NMR detector and the detection geometry of the robotic autosampler, sufficient resolution of variations in crosslink density on the millimeter scale could be determined. All data to date demonstrates that low-field NMR devices are a feasible tool for use in production settings for non-destructive quality control of polymer components.
Date: May 11, 2007
Creator: Chinn, S; Cook-Tendulkar, A; Maxwell, R; Wheeler, H; Wilson, M & Xie, Z
Object Type: Article
System: The UNT Digital Library
Massively Parallel QCD (open access)

Massively Parallel QCD

The theory of the strong nuclear force, Quantum Chromodynamics (QCD), can be numerically simulated from first principles on massively-parallel supercomputers using the method of Lattice Gauge Theory. We describe the special programming requirements of lattice QCD (LQCD) as well as the optimal supercomputer hardware architectures that it suggests. We demonstrate these methods on the BlueGene massively-parallel supercomputer and argue that LQCD and the BlueGene architecture are a natural match. This can be traced to the simple fact that LQCD is a regular lattice discretization of space into lattice sites while the BlueGene supercomputer is a discretization of space into compute nodes, and that both are constrained by requirements of locality. This simple relation is both technologically important and theoretically intriguing. The main result of this paper is the speedup of LQCD using up to 131,072 CPUs on the largest BlueGene/L supercomputer. The speedup is perfect with sustained performance of about 20% of peak. This corresponds to a maximum of 70.5 sustained TFlop/s. At these speeds LQCD and BlueGene are poised to produce the next generation of strong interaction physics theoretical results.
Date: April 11, 2007
Creator: Soltz, R.; Vranas, P.; Blumrich, M.; Chen, D.; Gara, A.; Giampap, M. et al.
Object Type: Article
System: The UNT Digital Library
Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines (open access)

Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines

A comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75 C and at 90 C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions.
Date: August 11, 2007
Creator: Rebak, R B; Ilevbare, G O & Carranza, R M
Object Type: Article
System: The UNT Digital Library
Seismic Source and Path Calibration in the Korean Peninsula, Yellow Sea (open access)

Seismic Source and Path Calibration in the Korean Peninsula, Yellow Sea

Two significant seismic events were analyzed using the crustal velocity model developed under this contract. The M{sub W} = 4.55 Korea earthquake of January 20, 2007 occurred in the Republic of Korea on land and within the dense digital seismic network. Using P-wave arrivals from 60 broadband, short-period and acceleration stations, the event occurred at 37.68N, 128.58E at a depth of 7.5 km at 20070120115653.8. Source inversion was performed using the accelerometer recordings in the 0.05-0.20 Hz band the broadband data in the 0.02-0.10 Hz band, with identical focal mechanisms and source depths of 9 and 11 km, respectively. This is the largest event on land in South Korea since the M{sub W} 4.7 event on December 13, 1996. Forward modeling of the waveforms at INCN and MDJ indicates the ability of the current model to match observations on the Korean Peninsula and the effect of significant pulse shape modification for paths that partially cross the Sea of Japan. The results of using the local network data provide a ground truth point for other studies analyzing seismic events on the peninsula. The isotropic seismic moment of the October 9, 2006 North Korea explosion was estimated from the Rayleigh-wave spectral amplitudes …
Date: July 11, 2007
Creator: Herrmann, R. B.; Walter, W. R. & Pasyanos, M.
Object Type: Article
System: The UNT Digital Library
Determining Transition State Geometries in Liquids Using 2D-IR (open access)

Determining Transition State Geometries in Liquids Using 2D-IR

Many properties of chemical reactions are determined by the transition state connecting reactant and product, yet it is difficult to directly obtain any information about these short-lived structures in liquids. We show that two-dimensional infrared (2D-IR) spectroscopy can provide direct information about transition states by tracking the transformation of vibrational modes as a molecule crossed a transition state. We successfully monitored a simple chemical reaction, the fluxional rearrangement of Fe(CO)5, in which the exchange of axial and equatorial CO ligands causes an exchange of vibrational energy between the normal modes of the molecule. This energy transfer provides direct evidence regarding the time scale, transition state, and mechanism of the reaction.
Date: December 11, 2007
Creator: Harris, Charles; Cahoon, James F.; Sawyer, Karma R.; Schlegel, Jacob P. & Harris, Charles B.
Object Type: Article
System: The UNT Digital Library
Remaining Sites Verification Package for the 100-C-9:2 Sanitary Sewer Pipelines, Waste Site Reclassification Form 2004-013 (open access)

Remaining Sites Verification Package for the 100-C-9:2 Sanitary Sewer Pipelines, Waste Site Reclassification Form 2004-013

The 100-C-9:2 sanitary sewer pipelines include the feeder pipelines associated with the 1607-B8, the 1607-B9, the 1607-B10 and the 1607-B11 septic systems. Contaminated soil and piping from the feeder lines to the septic systems were removed and disposed of. The remaining soil in the excavations has been shown to meet the remedial action objectives specified in the Remaining Sites ROD. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.
Date: July 11, 2007
Creator: Dittmer, L. M.
Object Type: Report
System: The UNT Digital Library