Nanostructured Assemblies of Thermoelectric Composite Materials (open access)

Nanostructured Assemblies of Thermoelectric Composite Materials

At the end of the funding period (March 2003) for our program in ferroelectric oxide nanomaterials, we had 3 publications in print, one more had been submitted and two more were in preparation in peer-reviewed journals and invited symposia lectures had been given since starting the project in the Fall of 1999. We hired two postdoctoral fellows, Dr. Ki-Seog Chang and Dr. Wenzhong Wang. We have also trained two graduate students, Ms. Keri Williams and Ms. Bernadette Hernandez, and one undergraduate student (Mr. Michael Scancella).
Date: February 26, 2008
Creator: Dorhout, Peter K. & Fisher, Ellen R.
Object Type: Report
System: The UNT Digital Library
Evaluating EUV mask pattern imaging with two EUV microscopes (open access)

Evaluating EUV mask pattern imaging with two EUV microscopes

Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool is …
Date: February 26, 2008
Creator: Goldberg, Kenneth A.; Takase, Kei; Naulleau, Patrick P.; Han, Hakseung; Barty, Anton; Kinoshita, Hiroo et al.
Object Type: Article
System: The UNT Digital Library
An Octadentate Luminescent Eu(III) 1,2-HOPO Chelate with PotentAqueous Stability (open access)

An Octadentate Luminescent Eu(III) 1,2-HOPO Chelate with PotentAqueous Stability

None
Date: February 26, 2007
Creator: Moore, Evan G.; Jocher, Christoph J.; Xu, Jide; Werner, Eric J. & Raymond,Kenneth N.
Object Type: Article
System: The UNT Digital Library
Thermal-Structural Analysis of the MacArthur Maze Freeway Collapse (open access)

Thermal-Structural Analysis of the MacArthur Maze Freeway Collapse

At approximately 3:41 AM on the morning of April 29, 2007, a tractor-trailer rig carrying 8,600 gallons (32.6 m{sup 3}) of fuel overturned on Interstate 880 in Oakland, CA. The resultant fire weakened the surrounding steel superstructure and caused a 50-yard (45.7 m) long section of the above connecting ramp from Interstate 80 to Interstate 580 to fail in approximately 18 minutes. In this study, we performed a loosely-coupled thermal-structural finite element analysis of the freeway using the LLNL Engineering codes NIKE3D, DYNA3D and TOPAZ3D. First, we applied an implicit structural code to statically initialize the stresses and displacements in the roadway at ambient conditions due to gravity loading. Next, we performed a thermal analysis by approximating the tanker fire as a moving box region of uniform temperature. This approach allowed for feasible calculation of the fire-to-structure radiative view factors and convective heat transport. We used a mass scaling methodology in the thermal analysis to reduce the overall simulation time so an explicit structural analysis could be used, which provided a more computationally efficient simulation of structural failure. Our approach showed structural failure of both spans due to thermal softening under gravity loading at approximately 20 minutes for a fixed …
Date: February 26, 2008
Creator: Noble, C. R.; Wemhoff, A. P. & McMichael, L. D.
Object Type: Article
System: The UNT Digital Library
Noise in a Calorimeter Readout System Using Periodic Sampling (open access)

Noise in a Calorimeter Readout System Using Periodic Sampling

Fourier transform analysis of the calorimeter noise problem gives quantitative results on (a) the time-height correlation, (b) the effect of background on optimal shaping and on the ENC, (c) sampling frequency requirements, and (d) the relation between sampling frequency and the required quantization error.
Date: February 26, 2009
Creator: Innes, Walter R.
Object Type: Report
System: The UNT Digital Library
Exciton dynamicsstudied via internal THz transitions (open access)

Exciton dynamicsstudied via internal THz transitions

We employ a novel, ultrafast terahertz probe to investigatethe dynamical interplay of optically-induced excitons and unboundelectron-hole pairs in GaAs quantum wells. Resonant creation ofheavy-hole excitons induces a new low-energy oscillator linked totransitions between the internal exciton degrees of freedom. The timeresolved terahertz optical conductivity is found to be a probe wellsuited for studies of fundamental processes such as formation, relaxationand ionization of excitons.
Date: February 26, 2003
Creator: Kaindl, R. A.; Hagele, D.; Carnahan, M. A.; Lovenich, R. & Chemla, D. S.
Object Type: Article
System: The UNT Digital Library
Compound-Nuclear Reaction Cross Sections from Surrogate Measurements: Status and Challenges (open access)

Compound-Nuclear Reaction Cross Sections from Surrogate Measurements: Status and Challenges

None
Date: February 26, 2008
Creator: Escher, J.
Object Type: Article
System: The UNT Digital Library
Identifying Oil Exploration Leads using Intergrated Remote Sensing and Seismic Data Analysis, Lake Sakakawea, Fort Berthold Indian Reservation, Willistion Basin (open access)

Identifying Oil Exploration Leads using Intergrated Remote Sensing and Seismic Data Analysis, Lake Sakakawea, Fort Berthold Indian Reservation, Willistion Basin

The Fort Berthold Indian Reservation, inhabited by the Arikara, Mandan and Hidatsa Tribes (now united to form the Three Affiliated Tribes) covers a total area of 1530 mi{sup 2} (980,000 acres). The Reservation is located approximately 15 miles east of the depocenter of the Williston basin, and to the southeast of a major structural feature and petroleum producing province, the Nesson anticline. Several published studies document the widespread existence of mature source rocks, favorable reservoir/caprock combinations, and production throughout the Reservation and surrounding areas indicating high potential for undiscovered oil and gas resources. This technical assessment was performed to better define the oil exploration opportunity, and stimulate exploration and development activities for the benefit of the Tribes. The need for this assessment is underscored by the fact that, despite its considerable potential, there is currently no meaningful production on the Reservation, and only 2% of it is currently leased. Of particular interest (and the focus of this study) is the area under the Lake Sakakawea (formed as result of the Garrison Dam). This 'reservoir taking' area, which has never been drilled, encompasses an area of 150,000 acres, and represents the largest contiguous acreage block under control of the Tribes. Furthermore, …
Date: February 26, 2004
Creator: Reeves, Scott R. & Billingsley, Randal L.
Object Type: Report
System: The UNT Digital Library
Spectroscopy of neutron-rich palladium and cadmium isotopes near A=120 (open access)

Spectroscopy of neutron-rich palladium and cadmium isotopes near A=120

New high-spin levels have been identified in the nucleus {sup 120}Pd from analysis of the coincidence gamma rays observed in the {sup 238}U({alpha}, f{gamma}{gamma}{gamma}) reaction. Recoiling fragments were detected with the Rochester heavy-ion detector array, CHICO, in coincidence with gamma-rays using Gammasphere. An A=110-130 mass-gated {gamma} - {gamma} - {gamma} cube from this experiment was constructed and analyzed for coincident gamma-rays in several nuclei near A=120. New results for neutron-rich {sup 118}Pd and {sup 120}Pd have been obtained. The {sup 120}Pd level scheme was extended to spin of 10{sup +} by building on the new low-energy gamma rays identified in decay studies of {sup 120}Rh. The details of the {sup 118}Pd level scheme derived from this work are compared to previous work. The systematics of the yrast levels in even-even Pd and Cd isotopes are presented and the symmetry of energy levels around N = 68 is discussed. A new 10{sup +} level in {sup 124}Cd has been observed. The population intensity of even-even neutron-rich Cd isotopes is deduced, indicating that nuclides near {sup 120}Cd are preferentially populated following alpha-induced fission of {sup 238}U.
Date: February 26, 2008
Creator: Stoyer, M A & Walters, W B
Object Type: Article
System: The UNT Digital Library
A review of ground-based heavy-ion radiobiology relevant to space radiation risk assessment: Part II. Cardiovascular and immunological effects (open access)

A review of ground-based heavy-ion radiobiology relevant to space radiation risk assessment: Part II. Cardiovascular and immunological effects

The future of manned space flight depends on an analysis of the numerous potential risks of travel into deep space. Currently no radiation dose limits have been established for these exploratory missions. To set these standards more information is needed about potential acute and late effects on human physiology from appropriate radiation exposure scenarios, including pertinent radiation types and dose rates. Cancer risks have long been considered the most serious late effect from chronic daily relatively low-dose exposures to the complex space radiation environment. However, other late effects from space radiation exposure scenarios are under study in ground-based accelerator facilities and have revealed some unique particle radiation effects not observed with conventional radiations. A comprehensive review of pertinent literature that considers tissue effects of radiation leading to functional detriments in specific organ systems has recently been published (NCRP National Council on Radiation Protection and Measurements, Information Needed to Make Radiation Protection Recommendations for Space Missions Beyond Low-Earth Orbit, Report 153, Bethesda, MD, 2006). This paper highlights the review of two non-cancer concerns from this report: cardiovascular and immunological effects.
Date: February 26, 2007
Creator: Blakely, Eleanor A. & Chang, Polly Y.
Object Type: Article
System: The UNT Digital Library
Reduction of pertechnetate by acetohydroxamic acid: Formation of [TcNO(AHA)2(H2O)]+ and implications for the UREX process. (open access)

Reduction of pertechnetate by acetohydroxamic acid: Formation of [TcNO(AHA)2(H2O)]+ and implications for the UREX process.

Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the x-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry with the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a the d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but may be augmented by products of reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex (1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent; titration studies indicate a single species from pH 4.5 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The formation of 1 may strongly impact the fate of technetium in the nuclear fuel cycle.
Date: February 26, 2008
Creator: 1Harry Reid Center for Environmental Studies, Nuclear Science and Technology Division, University of Nevada, Las Vegas, Las Vegas, NV, 89154-4006; Gong, Cynthia-May S; Poineau, Frederic; Lukens, Wayne W & Czerwinski, Kenneth R.
Object Type: Article
System: The UNT Digital Library
Stochastic Hard-Sphere Dynamics for Hydrodynamics of Non-Ideal Fluids (open access)

Stochastic Hard-Sphere Dynamics for Hydrodynamics of Non-Ideal Fluids

A novel stochastic fluid model is proposed with a nonideal structure factor consistent with compressibility, and adjustable transport coefficients. This stochastic hard-sphere dynamics (SHSD) algorithm is a modification of the direct simulation Monte Carlo algorithm and has several computational advantages over event-driven hard-sphere molecular dynamics. Surprisingly, SHSD results in an equation of state and a pair correlation function identical to that of a deterministic Hamiltonian system of penetrable spheres interacting with linear core pair potentials. The fluctuating hydrodynamic behavior of the SHSD fluid is verified for the Brownian motion of a nanoparticle suspended in a compressible solvent.
Date: February 26, 2008
Creator: Donev, A; Alder, B J & Garcia, A L
Object Type: Article
System: The UNT Digital Library
Automotive Underhood Thermal Management Analysis Using 3-D Coupled Thermal-Hydrodynamic Computer Models: Thermal Radiation Modeling (open access)

Automotive Underhood Thermal Management Analysis Using 3-D Coupled Thermal-Hydrodynamic Computer Models: Thermal Radiation Modeling

The goal of the radiation modeling effort was to develop and implement a radiation algorithm that is fast and accurate for the underhood environment. As part of this CRADA, a net-radiation model was chosen to simulate radiative heat transfer in an underhood of a car. The assumptions (diffuse-gray and uniform radiative properties in each element) reduce the problem tremendously and all the view factors for radiation thermal calculations can be calculated once and for all at the beginning of the simulation. The cost for online integration of heat exchanges due to radiation is found to be less than 15% of the baseline CHAD code and thus very manageable. The off-line view factor calculation is constructed to be very modular and has been completely integrated to read CHAD grid files and the output from this code can be read into the latest version of CHAD. Further integration has to be performed to accomplish the same with STAR-CD. The main outcome of this effort is to obtain a highly scalable and portable simulation capability to model view factors for underhood environment (for e.g. a view factor calculation which took 14 hours on a single processor only took 14 minutes on 64 processors). …
Date: February 26, 2002
Creator: Pannala, S.; D'Azevedo, E. & Zacharia, T.
Object Type: Report
System: The UNT Digital Library
2009 EVALUATION OF TRITIUM REMOVAL AND MITIGATION TECHNOLOGIES FOR WASTEWATER TREATMENT (open access)

2009 EVALUATION OF TRITIUM REMOVAL AND MITIGATION TECHNOLOGIES FOR WASTEWATER TREATMENT

Since 1995, a state-approved land disposal site (SALDS) has received tritium contaminated effluents from the Hanford Site Effluent Treatment Facility (ETF). Tritium in this effluent is mitigated by storage in slow moving groundwater to allow extended time for decay before the water reaches the site boundary. By this method, tritium in the SALDS is isolated from the general environment and human contact until it has decayed to acceptable levels. This report contains the 2009 update evaluation of alternative tritium mitigation techniques to control tritium in liquid effluents and groundwater at the Hanford site. A thorough literature review was completed and updated information is provided on state-of-the-art technologies for control of tritium in wastewaters. This report was prepared to satisfy the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-026-07B (Ecology, EPA, and DOE 2007). Tritium separation and isolation technologies are evaluated periodically to determine their feasibility for implementation to control Hanford site liquid effluents and groundwaters to meet the Us. Code of Federal Regulations (CFR), Title 40 CFR 141.16, drinking water maximum contaminant level (MCL) for tritium of 20,000 pOll and/or DOE Order 5400.5 as low as reasonably achievable (ALARA) policy. Since the 2004 evaluation, there have been …
Date: February 26, 2009
Creator: KJ, LUECK; DJ, GENESSE & GE, STEGEN
Object Type: Report
System: The UNT Digital Library
Calibration of Chemical Kinetic Models Using Simulations of Small-Scale Cookoff Experiments (open access)

Calibration of Chemical Kinetic Models Using Simulations of Small-Scale Cookoff Experiments

Establishing safe handling limits for explosives in elevated temperature environments is a difficult problem that often requires extensive simulation. The largest influence on predicting thermal cookoff safety lies in the chemical kinetic model used in these simulations, and these kinetic model reaction sequences often contain multiple steps. Several small-scale cookoff experiments, notably Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), One-Dimensional Time-to-Explosion (ODTX), and the Scaled Thermal Explosion (STEX) have been performed on various explosives to aid in cookoff behavior determination. Past work has used a single test from this group to create a cookoff model, which does not guarantee agreement with the other experiments. In this study, we update the kinetic parameters of an existing model for the common explosive 2,4,6-Trinitrotoluene (TNT) using DSC and ODTX experimental data at the same time by minimizing a global Figure of Merit based on hydrodynamic simulated data. We then show that the new kinetic model maintains STEX agreement, reduces DSC agreement, and improves ODTX and TGA agreement when compared to the original model. In addition, we describe a means to use implicit hydrodynamic simulations of DSC experiments to develop a reaction model for TNT melting.
Date: February 26, 2008
Creator: Wemhoff, A P; Becker, R C & Burnham, A K
Object Type: Article
System: The UNT Digital Library
Nuclear reactions used for superheavy element research (open access)

Nuclear reactions used for superheavy element research

Some of the most fascinating questions about the limits of nuclear stability are confronted in the heaviest nuclei. How many more new elements can be synthesized? What are the nuclear and chemical properties of these exotic nuclei? Does the 'Island of Stability' exist and can we ever explore the isotopes inhabiting that nuclear region? This paper will focus on the current experimental research on the synthesis and characterization of superheavy nuclei with Z > 112 from the Dubna/Livermore collaboration. Reactions using 48Ca projectiles from the U400 cyclotron and actinide targets ({sup 233,238}U, {sup 237}Np, {sup 242,244}Pu, {sup 243}Am, {sup 245,248}Cm, {sup 249}Cf) have been investigated using the Dubna Gas Filled Recoil Separator in Dubna over the last 8 years. In addition, several experiments have been performed to investigate the chemical properties of some of the observed longer-lived isotopes produced in these reactions. Some comments will be made on nuclear reactions used for the production of the heaviest elements. A summary of the current status of the upper end of the chart of nuclides will be presented.
Date: February 26, 2008
Creator: Stoyer, M A
Object Type: Article
System: The UNT Digital Library
Nonaqueous Phase Liquid Dissolution in Porous Media: Multi-Scale Effects of Multi-Component Dissolution Kinetics on Cleanup Time (open access)

Nonaqueous Phase Liquid Dissolution in Porous Media: Multi-Scale Effects of Multi-Component Dissolution Kinetics on Cleanup Time

Industrial organic solvents such as trichloroethylene (TCE) and tetrachloroethylene (PCE) constitute a principal class of groundwater contaminants. Cleanup of groundwater plume source areas associated with these compounds is problematic, in part, because the compounds often exist in the subsurface as dense nonaqueous phase liquids (DNAPLs). Ganglia (or 'blobs') of DNAPL serve as persistent sources of contaminants that are difficult to locate and remediate (e.g. Fenwick and Blunt, 1998). Current understanding of the physical and chemical processes associated with dissolution of DNAPLs in the subsurface is incomplete and yet is critical for evaluating long-term behavior of contaminant migration, groundwater cleanup, and the efficacy of source area cleanup technologies. As such, a goal of this project has been to contribute to this critical understanding by investigating the multi-phase, multi-component physics of DNAPL dissolution using state-of-the-art experimental and computational techniques. Through this research, we have explored efficient and accurate conceptual and numerical models for source area contaminant transport that can be used to better inform the modeling of source area contaminants, including those at the LLNL Superfund sites, to re-evaluate existing remediation technologies, and to inspire or develop new remediation strategies. The problem of DNAPL dissolution in natural porous media must be viewed …
Date: February 26, 2007
Creator: McNab, W.; Ezzedine, S. & Detwiler, R.
Object Type: Report
System: The UNT Digital Library
Technical Letter Report - Analysis of Ultrasonic Data on Piping Cracks at Ignalina Nuclear Power Plant Before and After Applying a Mechanical Stress Improvement Process, JCN-N6319, Task 2 (open access)

Technical Letter Report - Analysis of Ultrasonic Data on Piping Cracks at Ignalina Nuclear Power Plant Before and After Applying a Mechanical Stress Improvement Process, JCN-N6319, Task 2

Pacific Northwest National Laboratory (PNNL) is assisting the United States Nuclear Regulatory Commission (NRC) in developing a position on the management of primary water stress corrosion cracking (PWSCC) in piping systems previously analyzed for leak-before-break (LBB). Part of this work involves determining whether inspections alone are sufficient or if inspections plus mitigation techniques are needed. The work described in this report addresses the reliability of ultrasonic phased-array (PA) examinations for inspection of cracks that have been subjected to the mitigation method of mechanical stress improvement process (MSIP). It is believed that stresses imparted during MSIP may make ultrasonic crack responses in piping welds more difficult to detect and accurately characterize. To explore this issue, data were acquired, both before and after applying MSIP, and analyzed from cracked areas in piping at the Ignalina Nuclear Power Plant (INPP) in Lithuania. This work was performed under NRC Project JCN-N6319, PWSCC in Leak-Before-Break Systems.
Date: February 26, 2008
Creator: Anderson, Michael T.; Cumblidge, Stephen E. & Crawford, Susan L.
Object Type: Report
System: The UNT Digital Library
October 2008 Monitoring Results for Barnes, Kansas. (open access)

October 2008 Monitoring Results for Barnes, Kansas.

The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at Barnes, Kansas, during most of the interval 1949-1974. Carbon tetrachloride contamination was initially detected in 1986 in the town's public water supply wells. In 2006-2007, the CCC/USDA conducted a comprehensive targeted investigation at and near its former property in Barnes to characterize this contamination. Those results were reported previously (Argonne 2008a). In November 2007, the CCC/USDA began quarterly groundwater monitoring at Barnes. The monitoring is being conducted on behalf of the CCC/USDA by Argonne National Laboratory, in accord with the recommendations made in the report for the 2006-2007 targeted investigation (Argonne 2008a). The objective is to monitor the carbon tetrachloride contamination identified in the groundwater at Barnes. The sampling is presently conducted in a network of 28 individual monitoring wells (at 19 distinct locations), 2 public water supply wells, and 1 private well (Figure 1.1). The results of the 2006-2007 targeted investigation and the subsequent monitoring events in November 2007 (Argonne 2008b), March 2008 (Argonne 2008c), and July 2008 (Argonne 2008d) demonstrated the presence of carbon tetrachloride contamination in groundwater at levels exceeding the Kansas Department of Health and Environment (KDHE) Tier 2 …
Date: February 26, 2009
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Environmental Compliance and Protection Program Description Oak Ridge, Tennessee (open access)

Environmental Compliance and Protection Program Description Oak Ridge, Tennessee

The objective of the Environmental Compliance and Protection (EC and P) Program Description (PD) is to establish minimum environmental compliance requirements and natural resources protection goals for the Bechtel Jacobs Company LLC (BJC) Oak Ridge Environmental Management Cleanup Contract (EMCC) Contract Number DE-AC05-98OR22700-M198. This PD establishes the work practices necessary to ensure protection of the environment during the performance of EMCC work activities on the US Department of Energy's (DOE's) Oak Ridge Reservation (ORR) in Oak Ridge, Tennessee, by BJC employees and subcontractor personnel. Both BJC and subcontractor personnel are required to implement this PD. A majority of the decontamination and demolition (D and D) activities and media (e.g., soil and groundwater) remediation response actions at DOE sites on the ORR are conducted under the authority of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). CERCLA activities are governed by individual CERCLA decision documents (e.g., Record of Decision [ROD] or Action Memorandum) and according to requirements stated in the Federal Facility Agreement for the Oak Ridge Reservation (DOE 1992). Applicable or relevant and appropriate requirements (ARARs) for the selected remedy are the requirements for environmental remediation responses (e.g., removal actions and remedial actions) conducted under CERCLA.
Date: February 26, 2009
Creator: Bechtel Jacobs
Object Type: Report
System: The UNT Digital Library
On the importance of nuclear quantum motions in near edge x-ray absorption fine structure (NEXAFS) spectroscopy of molecules (open access)

On the importance of nuclear quantum motions in near edge x-ray absorption fine structure (NEXAFS) spectroscopy of molecules

We report the effects of sampling nuclear quantum motion with path integral molecular dynamics (PIMD) on calculations of the nitrogen K-edge spectra of two isolated organic molecules. S-triazine, a prototypical aromatic molecule occupying primarily its vibrational ground state at room temperature, exhibits substantially improved spectral agreement when nuclear quantum effects are included via PIMD, as compared to the spectra obtained from either a single fixed-nuclei based calculation or from a series of configurations extracted from a classical molecular dynamics trajectory. Nuclear quantum dynamics can accurately explain the intrinsic broadening of certain features. Glycine, the simplest amino acid, is problematic due to large spectral variations associated with multiple energetically accessible conformations at the experimental temperature. This work highlights the sensitivity of NEXAFS to quantum nuclear motions in molecules, and the necessity of accurately sampling such quantum motion when simulating their NEXAFS spectra.
Date: February 26, 2009
Creator: Schwartz, Craig P.; Uejio, Janel S.; Saykally, Richard J. & Prendergast, David
Object Type: Article
System: The UNT Digital Library
TANK 40 FINAL SB5 CHEMICAL CHARACTERIZATION RESULTS PRIOR TO NP ADDITION (open access)

TANK 40 FINAL SB5 CHEMICAL CHARACTERIZATION RESULTS PRIOR TO NP ADDITION

A sample of Sludge Batch 5 (SB5) was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). This sample was also analyzed for chemical composition including noble metals. Prior to radionuclide inventory analyses, a final sample of the H-canyon Np stream will be added to bound the Np addition anticipated for Tank 40. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to DWPF as SB5. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB5 sample was transferred from the shipping container into a 4-L high density polyethylene vessel and solids allowed to settle overnight. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 239 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon{reg_sign} vessels and four in Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Due to the …
Date: February 26, 2009
Creator: Bannochie, C & Damon Click, D
Object Type: Report
System: The UNT Digital Library
Bioforensics: Characterization of biological weapons agents by NanoSIMS (open access)

Bioforensics: Characterization of biological weapons agents by NanoSIMS

The anthrax attacks of Fall 2001 highlight the need to develop forensic methods based on multiple identifiers to determine the origin of biological weapons agents. Genetic typing methods (i.e., DNA and RNA-based) provide one attribution technology, but genetic information alone is not usually sufficient to determine the provenance of the material. Non-genetic identifiers, including elemental and isotopic signatures, provide complementary information that can be used to identify the means, geographic location and date of production. Under LDRD funding, we have successfully developed the techniques necessary to perform bioforensic characterization with the NanoSIMS at the individual spore level. We have developed methods for elemental and isotopic characterization at the single spore scale. We have developed methods for analyzing spore sections to map elemental abundance within spores. We have developed rapid focused ion beam (FIB) sectioning techniques for spores to preserve elemental and structural integrity. And we have developed a high-resolution depth profiling method to characterize the elemental distribution in individual spores without sectioning. We used these newly developed methods to study the controls on elemental abundances in spores, characterize the elemental distribution of in spores, and to study elemental uptake by spores. Our work under this LDRD project attracted FBI and …
Date: February 26, 2007
Creator: Weber, P K; Ghosal, S; Leighton, T J; Wheeler, K E & Hutcheon, I D
Object Type: Report
System: The UNT Digital Library
Feed Preparation for Source of Alkali Melt Rate Tests (open access)

Feed Preparation for Source of Alkali Melt Rate Tests

The purpose of the Source of Alkali testing was to prepare feed for melt rate testing in order to determine the maximum melt-rate for a series of batches where the alkali was increased from 0% Na{sub 2}O in the frit (low washed sludge) to 16% Na{sub 2}O in the frit (highly washed sludge). This document summarizes the feed preparation for the Source of Alkali melt rate testing. The Source of Alkali melt rate results will be issued in a separate report. Five batches of Sludge Receipt and Adjustment Tank (SRAT) product and four batches of Slurry Mix Evaporator (SME) product were produced to support Source of Alkali (SOA) melt rate testing. Sludge Batch 3 (SB3) simulant and frit 418 were used as targets for the 8% Na{sub 2}O baseline run. For the other four cases (0% Na{sub 2}O, 4% Na{sub 2}O, 12% Na{sub 2}O, and 16% Na{sub 2}O in frit), special sludge and frit preparations were necessary. The sludge preparations mimicked washing of the SB3 baseline composition, while frit adjustments consisted of increasing or decreasing Na and then re-normalizing the remaining frit components. For all batches, the target glass compositions were identical. The five SRAT products were prepared for testing …
Date: February 26, 2005
Creator: Stone, M. E. & Lambert, D. P.
Object Type: Report
System: The UNT Digital Library