Development of a performance-based industrial energy efficiency indicator for cement manufacturing plants. (open access)

Development of a performance-based industrial energy efficiency indicator for cement manufacturing plants.

Organizations that implement strategic energy management programs have the potential to achieve sustained energy savings if the programs are carried out properly. A key opportunity for achieving energy savings that plant managers can take is to determine an appropriate level of energy performance by comparing the plant performance with that of similar plants in the same industry. Manufacturing plants can set energy efficiency targets by using performance-based indicators. The U.S. Environmental Protection Agency (EPA), through its ENERGY STAR{reg_sign} program, has been developing plant energy performance indicators (EPIs) to encourage a variety of U.S. industries to use energy more efficiently. This report describes work with the cement manufacturing industry to provide a plant-level indicator of energy efficiency for assembly plants that produce a variety of products, including Portland cement and other specialty cement products, in the United States. Consideration is given to the role that performance-based indicators play in motivating change; the steps needed to develop indicators, including interacting with an industry to secure adequate data for an indicator; and the actual application and use of an indicator when complete. How indicators are employed in the EPA's efforts to encourage industries to voluntarily improve their use of energy is discussed as …
Date: July 21, 2006
Creator: Boyd, G. & Sciences, Decision and Information
Object Type: Report
System: The UNT Digital Library
X-ray survival characteristics and genetic analysis for nineSaccharomyces deletion mutants that affect radiation sensitivity (open access)

X-ray survival characteristics and genetic analysis for nineSaccharomyces deletion mutants that affect radiation sensitivity

We examine ionizing radiation (IR) sensitivity and epistasisrelationships of several Saccharomyces mutants affectingpost-translational modifications of histones H2B and H3. Mutantsbre1delta, lge1delta, and rtf1delta, defective in histone H2B lysine 123ubiquitination, show IR sensitivity equivalent to that of the dot1deltamutant that we reported on earlier, consistent with published findingsthat Dot1p requires H2B K123 ubiquitination to fully methylate histone H3K79. This implicates progressive K79 methylation rather thanmono-methylation in IR resistance. The set2delta mutant, defective in H3K36 methylation, shows mild IR sensitivity whereas mutants that abolishH3 K4 methylation resemble wild type. The dot1delta, bre1delta, andlge1delta mutants show epistasis for IR sensitivity. The paf1deltamutant, also reportedly defective in H2B K123 ubiquitination, confers nosensitivity. The rad6delta, rad51null, rad50delta, and rad9deltamutations are epistatic to bre1? and dot1delta, but rad18delta andrad5delta show additivity with bre1delta, dot1delta, and each other. Thebre1delta rad18delta double mutant resembles rad6delta in sensitivity;thus the role of Rad6p in ubiquitinating H2B accounts for its extrasensitivity compared to rad18delta. We conclude that IR resistanceconferred by BRE1 and DOT1 is mediated through homologous recombinationalrepair, not postreplication repair, and confirm findings of a G1checkpoint role for the RAD6/BRE1/DOT1 pathway.
Date: July 21, 2006
Creator: Game, John C.; Williamson, Marsha S. & Baccari, Clelia
Object Type: Article
System: The UNT Digital Library
Microscopic Approaches to Nuclear Structure: Configuration Interaction (open access)

Microscopic Approaches to Nuclear Structure: Configuration Interaction

The configuration interaction (CI) approach to solving the nuclear many-body problem, also known as the interacting shell model, has proven to be powerful tool in understanding the structure of nuclei. The principal criticism of past applications of the shell model is the reliance on empirical tuning to interaction matrix elements. If an accurate description of nuclei far from the valley of stability, where little or no data is available, a more fundamental approach is needed. This starts with recent ab initio approaches with effective interactions in the no-core shell model (NCSM). Using effective-field theory for guidance, fully ab initio descriptions of nuclei up to {sup 16}O with QCD based NN, NNN, and NNNN interactions will be possible within the next five years. An important task is then to determine how to use these NCSM results to develop effective interactions to describe heavier nuclei without the need to resort to an empirical retuning with every model space. Thus, it is likely that more traditional CI applications utilizing direct diagonalization and more fundamental interactions will be applicable to nuclei with perhaps up to one hundred constituents. But, these direct diagonalization CI applications will always be computationally limited due to the rapid increase …
Date: September 21, 2007
Creator: Ormand, W E
Object Type: Article
System: The UNT Digital Library
Drilling Specifications: Well Installations in the 300 Area to Support PNNL’s Integrated Field-Scale Subsurface Research Challenge (IFC) Project (open access)

Drilling Specifications: Well Installations in the 300 Area to Support PNNL’s Integrated Field-Scale Subsurface Research Challenge (IFC) Project

Part of the 300 Area Integrated Field-Scale Subsurface Research Challenge (IFC) will be installation of a network of high density borings and wells to monitor migration of fluids and contaminants (uranium), both in groundwater and vadose zone, away from an surface infiltration plot (Figure A-1). The infiltration plot will be located over an area of suspected contamination at the former 300 Area South Process Pond (SPP). The SPP is located in the southeastern portion of the Hanford Site, within the 300-FF-5 Operable Unit. Pacific Northwest National Laboratory (PNNL) with the support of FH shall stake the well locations prior to the start of drilling. Final locations will be based on accessibility and will avoid any surface or underground structures or hazards as well as surface contamination.
Date: January 21, 2008
Creator: Bjornstad, Bruce N. & Vermeul, Vince R.
Object Type: Report
System: The UNT Digital Library
THE METABOLSIM AND TOXICITY OF RADIUM-223 IN RATS (open access)

THE METABOLSIM AND TOXICITY OF RADIUM-223 IN RATS

This report covers studies of the excretion and retention of 'tracer' and toxic doses of the 11.2-day Ra{sup 223} isotope, its acute toxicity (organ weight changes, gross and microscopic pathology, and Fe{sup 59} utilization by the bone marrow), and long-term histopathological changes and alterations in the hemogram.
Date: February 21, 1958
Creator: Durbin, Patricia; Durbin, Patricia W.; Asling, C. Willet.; Jeung, Nylan; Williams, Marilyn H.; Post, James. et al.
Object Type: Report
System: The UNT Digital Library
Final Report for "Accurate Numerical Models of the Secondary Electron Yield from Grazing-incidence Collisions". (open access)

Final Report for "Accurate Numerical Models of the Secondary Electron Yield from Grazing-incidence Collisions".

Effects of stray electrons are a main factor limiting performance of many accelerators. Because heavy-ion fusion (HIF) accelerators will operate in regimes of higher current and with walls much closer to the beam than accelerators operating today, stray electrons might have a large, detrimental effect on the performance of an HIF accelerator. A primary source of stray electrons is electrons generated when halo ions strike the beam pipe walls. There is some research on these types of secondary electrons for the HIF community to draw upon, but this work is missing one crucial ingredient: the effect of grazing incidence. The overall goal of this project was to develop the numerical tools necessary to accurately model the effect of grazing incidence on the behavior of halo ions in a HIF accelerator, and further, to provide accurate models of heavy ion stopping powers with applications to ICF, WDM, and HEDP experiments.
Date: October 21, 2008
Creator: Veitzer, Seth A
Object Type: Report
System: The UNT Digital Library
ANGULAR DISTRIBUTION OF FRAGMENTS FROM FISSION INDUCED BY HEAVYIONS IN GOLD AND BISMUTH (open access)

ANGULAR DISTRIBUTION OF FRAGMENTS FROM FISSION INDUCED BY HEAVYIONS IN GOLD AND BISMUTH

We present the results of measurements of the angular distribution of fission fragments produced by irradiation of Au{sup 197} and Bi{sup 209} with various heavy ions. The projectiles, B{sup 11}, C{sup 12}, N{sup 14}, and O{sup 16}, had energies from a few MeV above the Coulomb barrier to 10.4 MeV per nucleon. The gross features of these results can be explained by use of a model and parameters that have been used by others to account for angular distributions of fission fragments from helium-ion bombardments. In detail, however, these results appear to indicate that the models used to predict the average value of the angular momentum of the compound nucleus give values too low near the Coulomb barrier. Furthermore, at high bombarding energies it is necessary to consider the fact that appreciable direct interaction is taking place.
Date: May 21, 1962
Creator: Viola, Victor E.; Thomas, T. Darrah & Seaborg, Glenn T.
Object Type: Report
System: The UNT Digital Library
Negative Transconductance in Apertured Electron Guns (open access)

Negative Transconductance in Apertured Electron Guns

Passing an electron beam through an aperture can serve to reduce the beam current or change the transverse beam profile. For a sufficiently intense beam, space charge will drive a radial expansion of the beam, which may cause the current passing through the aperture to increase even though the current arriving at the aperture is decreasing. When a gridded electron gun is used, this may be expressed by stating that the transconductance of the apertured gun is negative. Here we explain this effect, and explore some of the key factors governing when it can occur and influencing its strength.
Date: September 21, 2007
Creator: Harris, J R & O'Shea, P G
Object Type: Article
System: The UNT Digital Library
IMPACT OF ALUMINATE IONS ON THE PROPERTIES OF SALTSTONE GROUT MIXES (open access)

IMPACT OF ALUMINATE IONS ON THE PROPERTIES OF SALTSTONE GROUT MIXES

It is important to identify and control the operational and compositional variables that impact the important processing and performance properties of Saltstone grout mixes. The grout that is produced at the Saltstone Production Facility (SPF) is referred to as Saltstone and is a waste form that immobilizes low concentrations of radionuclides as well as certain toxic metals. The Saltstone will be disposed of in vaults at Savannah River Site (SRS). An effort referred to as the Saltstone Variability Study has been initiated to achieve this goal. The protocols developed in this variability study are also ideally suited as a tool to assess the impact of proposed changes to the processing flow sheet for Liquid Waste Operations at SRS. One such proposal that is currently under consideration is to introduce a leaching step in the treatment of the High Level Waste (HLW) sludge to remove aluminum prior to vitrification at the Defense Waste Processing Facility (DWPF). This leachate would significantly increase the soluble aluminate concentration in the salt feed that will be processed at the SPF. Consequently, an initial study of the impact of increased aluminate concentration on the Saltstone grout properties was performed. Prior work by Lukens (1) showed that …
Date: February 21, 2008
Creator: Harbour, J; Tommy Edwards, T; Erich Hansen, E & Vickie Williams, V
Object Type: Article
System: The UNT Digital Library
Borehole Seismic Monitoring of Injected CO2 at the Frio Site (open access)

Borehole Seismic Monitoring of Injected CO2 at the Frio Site

As part of a small scale sequestration test (about 1500 tonsof CO2) in a saline aquifer, time-lapse borehole seismic surveys wereconducted to aid in characterization of subsurface CO2 distribution andmaterial property changes induced by the injected CO2. A VSP surveydemonstrated a large increase (about 75 percent) in seismic reflectivitydue to CO2 injection and allowed estimation of the spatial extent of CO2induced changes. A crosswell survey imaged a large seismic velocitydecrease (up to 500 m/s) within the injection interval and provided ahigh resolution image of this velocity change which maps the subsurfacedistribution of CO2 between two wells. Numerical modeling of the seismicresponse uses the crosswell measurements to show that this small CO2volume causes a large response in the seismic reflectivity. This resultdemonstrates that seismic detection of small CO2 volumes in salineaquifers is feasible and realistic.
Date: April 21, 2006
Creator: Daley, Thomas M.; Myer, Larry R.; Hoversten, G.M.; Peterson, JohnE. & Korneev, Valeri A.
Object Type: Article
System: The UNT Digital Library
Microwave Treatment as a Pesticide Alternative for Stored-Products (open access)

Microwave Treatment as a Pesticide Alternative for Stored-Products

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Date: May 21, 2003
Creator: Bigelow, T.; Forrester, S.; Halverson, S.; Halverson, B. & Phillips, T.
Object Type: Report
System: The UNT Digital Library
Object Classification at the Nearby Supernova Factory (open access)

Object Classification at the Nearby Supernova Factory

We present the results of applying new object classification techniques to the supernova search of the Nearby Supernova Factory. In comparison to simple threshold cuts, more sophisticated methods such as boosted decision trees, random forests, and support vector machines provide dramatically better object discrimination: we reduced the number of nonsupernova candidates by a factor of 10 while increasing our supernova identification efficiency. Methods such as these will be crucial for maintaining a reasonable false positive rate in the automated transient alert pipelines of upcoming large optical surveys.
Date: December 21, 2007
Creator: Aragon, Cecilia R.; Bailey, Stephen; Aragon, Cecilia R.; Romano, Raquel; Thomas, Rollin C.; Weaver, B. A. et al.
Object Type: Article
System: The UNT Digital Library
Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems (open access)

Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems

We propose and analyze a new tool to help solve sparse linear least-squares problems min{sub x} {parallel}Ax-b{parallel}{sub 2}. Our method is based on a sparse QR factorization of a low-rank perturbation {cflx A} of A. More precisely, we show that the R factor of {cflx A} is an effective preconditioner for the least-squares problem min{sub x} {parallel}Ax-b{parallel}{sub 2}, when solved using LSQR. We propose applications for the new technique. When A is rank deficient we can add rows to ensure that the preconditioner is well-conditioned without column pivoting. When A is sparse except for a few dense rows we can drop these dense rows from A to obtain {cflx A}. Another application is solving an updated or downdated problem. If R is a good preconditioner for the original problem A, it is a good preconditioner for the updated/downdated problem {cflx A}. We can also solve what-if scenarios, where we want to find the solution if a column of the original matrix is changed/removed. We present a spectral theory that analyzes the generalized spectrum of the pencil (A*A,R*R) and analyze the applications.
Date: March 21, 2008
Creator: Avron, Haim; Ng, Esmond G. & Toledo, Sivan
Object Type: Article
System: The UNT Digital Library
Kinetic Effects in the Self-Assembly of Pure and Mixed Tetradecyland Octadecylamine Molecules on Mica (open access)

Kinetic Effects in the Self-Assembly of Pure and Mixed Tetradecyland Octadecylamine Molecules on Mica

The self-assembly of tetradecylamine (C14) and of mixtures of tetradecyl and octadecylamine (C18) molecules from chloroform solutions on mica has been studied using atomic force microscopy(AFM). For pure components self-assembly proceeds more slowly for C14 than for C18. In both cases after equilibrium is reached islands of tilted molecules cover a similar fraction of the surface. Images of films formed by mixtures of molecules acquired before equilibrium is reached (short ripening time at room temperature) show only islands with the height corresponding to C18 with many pores. After a long ripening time, when equilibrium is reached, islands of segregated pure components are formed.
Date: September 21, 2005
Creator: Benitez, J. J. & Salmeron, M.
Object Type: Article
System: The UNT Digital Library
Energy Efficiency and Least-Cost Planning: The Best Way to Save Money and Reduce Energy Use in Hawaii (open access)

Energy Efficiency and Least-Cost Planning: The Best Way to Save Money and Reduce Energy Use in Hawaii

If the 500 MW geothermal project on the Big Island of Hawaii is developed as planned, the Wao Kele O Puna rain forest will be severely damaged or destroyed. If this happens the State will lose one of its most precious resources. It would be tragic for this to happen, since on a least-cost basis, the geothermal project does not make economic sense. Improving energy efficiency in the commercial and residential sectors of Hawaii can save about 500 MW of power at a cost of $700 million.
Date: May 21, 1990
Creator: Mowris, Robert J.
Object Type: Report
System: The UNT Digital Library
Comparison of Cluster Lensing Profiles with Lambda CDM Predictions (open access)

Comparison of Cluster Lensing Profiles with Lambda CDM Predictions

We derive lens distortion and magnification profiles of four well known clusters observed with Subaru. Each cluster is very well fitted by the general form predicted for Cold Dark Matter (CDM) dominated halos, with good consistency found between the independent distortion and magnification measurements. The inferred level of mass concentration is surprisingly high, 8 < c{sub vir} < 15 (<c{sub vir}> = 10.39 {+-} 0.91), compared to the relatively shallow profiles predicted by the {Lambda}CDM model, c{sub vir} = 5.06 {+-} 1.10 (for <M{sub vir}> = 1.25 x 10{sup 15} M{sub {circle_dot}}/h). This represents a 4{sigma} discrepancy, and includes the relatively modest effects of projection bias and profile evolution derived from N-body simulations, which oppose each other with little residual effect. In the context of CDM based cosmologies, this discrepancy implies some modification of the widely assumed spectrum of initial density perturbations, so clusters collapse earlier (z {ge} 1) than predicted (z < 0.5) when the Universe was correspondingly denser.
Date: May 21, 2008
Creator: Broadhurst, Tom; U., /Tel Aviv; Umetsu, Keiichi; /Taipei, Inst. Astron. Astrophys.; Medezinski, Elinor; U., /Tel Aviv et al.
Object Type: Article
System: The UNT Digital Library
A Beamline for High Pressure Studies at the Advanced Light Source With a Superconducting Bending Magnet as the Source (open access)

A Beamline for High Pressure Studies at the Advanced Light Source With a Superconducting Bending Magnet as the Source

A new facility for high-pressure diffraction and spectroscopy using diamond anvil high-pressure cells has been built at the Advanced Light Source on Beamline 12.2.2. This beamline benefits from the hard X-radiation generated by a 6 Tesla superconducting bending magnet (superbend). Useful x-ray flux is available between 5 keV and 35 keV. The radiation is transferred from the superbend to the experimental enclosure by the brightness preserving optics of the beamline. These optics are comprised of: a plane parabola collimating mirror (M1), followed by a Kohzu monochromator vessel with a Si(111) crystals (E/{Delta}E {approx} 7000) and a W/B{sub 4}C multilayer (E/{Delta}E {approx} 100), and then a toroidal focusing mirror (M2) with variable focusing distance. The experimental enclosure contains an automated beam positioning system, a set of slits, ion chambers, the sample positioning goniometry and area detectors (CCD or image-plate detector). Future developments aim at the installation of a second end station dedicated for in situ laser-heating on one hand and a dedicated high-pressure single-crystal station, applying both monochromatic as well as polychromatic techniques.
Date: April 21, 2005
Creator: Kunz, M.; MacDowell, A. A.; Caldwell, W. A.; Cambie, D.; Celestre, R. S.; Domning, E. E. et al.
Object Type: Article
System: The UNT Digital Library
Earth Systems Science and Engineering (open access)

Earth Systems Science and Engineering

Providing the essential energy and water systems to support human needs while understanding and addressing their environmental consequences is a watershed problem for the 21st century. The LLNL Earth System Science and Engineering Program seeks to provide the scientific understanding and technological expertise to help provide solutions at both global and regional scales. Our work is highly collaborative with universities, laboratories and industrial partners across the world and involves observational data, laboratory experiments, and numerical simulations. The energy systems we have enjoyed for the last 100 years have resulted in the advanced standard of living in the developed world and a major emerging problem with climate change. Now we face a simultaneous realization that our reliance on fossil fuels is a source of conflict and economic disruption as well as causing potentially abrupt, even catastrophic global climate change. The climate and energy problem is perhaps the greatest challenge ever faced by mankind. Fossil fuel remains the least expensive and most available source of energy and the basis of our economy. The use of fossil fuels, especially over the last 100 years has led to a 30% increase in CO{sub 2} in the atmosphere. The problem is growing. The population of …
Date: February 21, 2006
Creator: Rotman, D A
Object Type: Report
System: The UNT Digital Library
K-alpha conversion efficiency measurments for x-ray scattering in inertial confinement fusion plasmas (open access)

K-alpha conversion efficiency measurments for x-ray scattering in inertial confinement fusion plasmas

The conversion efficiency of ultra short-pulse laser radiation to K-{alpha} x-rays has been measured for various chlorine-containing targets to be used as x-ray scattering probes of dense plasmas. The spectral and temporal properties of these sources will allow spectrally-resolved x-ray scattering probing with picosecond temporal resolution required for measuring the plasma conditions in inertial confinement fusion experiments. Simulations of x-ray scattering spectra from these plasmas show that fuel capsule density, capsule ablator density, and shock timing information may be inferred.
Date: November 21, 2006
Creator: Kritcher, A L; Neumayer, P; Urry, M K; Robey, H; Niemann, C; Landen, O L et al.
Object Type: Article
System: The UNT Digital Library
Discrimination Report: ESTCP UXO Discrimination Study, ESTCPProject #MM-0437 (open access)

Discrimination Report: ESTCP UXO Discrimination Study, ESTCPProject #MM-0437

The FY06 Defense Appropriation contains funding for the 'Development of Advanced, Sophisticated, Discrimination Technologies for UXO Cleanup' in the Environmental Security Technology Certification Program. In 2003, the Defense Science Board observed: 'The problem is that instruments that can detect the buried UXOs also detect numerous scrap metal objects and other artifacts, which leads to an enormous amount of expensive digging. Typically 100 holes may be dug before a real UXO is unearthed! The Task Force assessment is that much of this wasteful digging can be eliminated by the use of more advanced technology instruments that exploit modern digital processing and advanced multi-mode sensors to achieve an improved level of discrimination of scrap from UXOs.' Significant progress has been made in discrimination technology. To date, testing of these approaches has been primarily limited to test sites with only limited application at live sites. Acceptance of discrimination technologies requires demonstration of system capabilities at real UXO sites under real world conditions. Any attempt to declare detected anomalies to be harmless and requiring no further investigation require demonstration to regulators of not only individual technologies, but of an entire decision making process. This discrimination study was be the first phase in what is …
Date: December 21, 2007
Creator: Gasperikova, Erika; Smith, J. Torquil; Morrison, H. Frank & Becker, Alex
Object Type: Report
System: The UNT Digital Library
Delaware Basin Monitoring Annual Report (open access)

Delaware Basin Monitoring Annual Report

The Delaware Basin Drilling Surveillance Program (DBDSP) is designed to monitor drilling activities in the vicinity of the Waste Isolation Pilot Plant (WIPP). This program is based on Environmental Protection Agency (EPA) requirements. The EPA environmental standards for the management and disposal of transuranic (TRU) radioactive waste are codified in 40 CFR Part 191 (EPA 1993). Subparts B and C of the standard address the disposal of radioactive waste. The standard requires the Department of Energy (DOE) to demonstrate the expected performance of the disposal system using a probabilistic risk assessment or performance assessment (PA). This PA must show that the expected repository performance will not release radioactive material above limits set by the EPA's standard. This assessment must include the consideration of inadvertent drilling into the repository at some future time.
Date: September 21, 2002
Creator: Washington Regulatory and Environmental Services
Object Type: Report
System: The UNT Digital Library
OXYGEN ISOTOPIC COMPOSITIONS OF THE ALLENDE TYPE C CAIs: EVIDENCE FOR ISOTOPIC EXCHANGE DURING NEBULAR MELTING AND ASTEROIDAL THERMAL METAMORPHISM (open access)

OXYGEN ISOTOPIC COMPOSITIONS OF THE ALLENDE TYPE C CAIs: EVIDENCE FOR ISOTOPIC EXCHANGE DURING NEBULAR MELTING AND ASTEROIDAL THERMAL METAMORPHISM

Based on the mineralogy and petrography, coarse-grained, igneous, anorthite-rich (Type C) calcium-aluminum-rich inclusions (CAIs) in the CV3 carbonaceous chondrite Allende have been recently divided into three groups: (i) CAIs with melilite and Al,Ti-diopside of massive and lacy textures (coarse grains with numerous rounded inclusions of anorthite) in a fine-grained anorthite groundmass (6-1-72, 100, 160), (ii) CAI CG5 with massive melilite, Al,Ti-diopside and anorthite, and (iii) CAIs associated with chondrule material: either containing chondrule fragments in their peripheries (ABC, TS26) or surrounded by chondrule-like, igneous rims (93) (Krot et al., 2007a,b). Here, we report in situ oxygen isotopic measurements of primary (melilite, spinel, Al,Ti-diopside, anorthite) and secondary (grossular, monticellite, forsterite) minerals in these CAIs. Spinel ({Delta}{sup 17}O = -25{per_thousand} to -20{per_thousand}), massive and lacy Al,Ti-diopside ({Delta}{sup 17}O = -20{per_thousand} to -5{per_thousand}) and fine-grained anorthite ({Delta}{sup 17}O = -15{per_thousand} to -2{per_thousand}) in 100, 160 and 6-1-72 are {sup 16}O-enriched relative spinel and coarse-grained Al,Ti-diopside and anorthite in ABC, 93 and TS26 ({Delta}{sup 17}O ranges from -20{per_thousand} to -15{per_thousand}, from -15{per_thousand} to -5{per_thousand}, and from -5{per_thousand} to 0{per_thousand}, respectively). In 6-1-72, massive and lacy Al,Ti-diopside grains are {sup 16}O-depleted ({Delta}{sup 17}O {approx} -13{per_thousand}) relative to spinel ({Delta}{sup 17}O = -23{per_thousand}). Melilite is the …
Date: February 21, 2008
Creator: Krot, A N; Chaussidon, M; Yurimoto, H; Sakamoto, N; Nagashima, K; Hutcheon, I D et al.
Object Type: Article
System: The UNT Digital Library
Characterization of Direct-Push Vadose Zone Sediments from the 241-B and 241-BX Tank Farms (open access)

Characterization of Direct-Push Vadose Zone Sediments from the 241-B and 241-BX Tank Farms

Geochemical tests provide evidence for the transit of a plume of caustic waste solution through the sediment column at the Hanford 241-B and -BX Tank Farms. Direct-push samples recovered from boreholes surrounding Tanks 241-B-110 and 241-BX-102 and related waste transfer lines and diversion boxes included sediments typical of those previously recovered from other localities on the Hanford Site. The Hanford formation sediments are dominantly quartzo-feldspathic sands strewn with lithic fragments, displaying a range of particle size distributions and sorting characteristics. Some moderately well-sorted, fine-grained lithologies are interpreted as lenticular bodies irregularly dispersed in coarser-grained, more poorly sorted sediments. Tier I tests conducted on the vadose zone sediments revealed an inverse correlation between moisture content and sediment size fraction (i.e., there is greater moisture content in finer-grained sediments). The Tier I tests also showed that the pore water solutions were likely sodium-rich, moderately saline, and possessed higher pH values than background (untainted) sediments. These data are characteristic of sediments that have encountered sodium-rich, saline, caustic waste solution, as documented in other reports at other suspect contamination sites around Hanford. Analyses of solutions from 1:1 water extracts reveal relatively balanced cation and anion concentrations, indicating that most of the geochemical species have …
Date: December 21, 2007
Creator: Brown, Christopher F.; Icenhower, Jonathan P.; Um, Wooyong; Bjornstad, Bruce N.; Valenta, Michelle M.; Iovin, Cristian et al.
Object Type: Report
System: The UNT Digital Library
A table-top femtosecond time-resolved soft x-ray transient absorption spectrometer (open access)

A table-top femtosecond time-resolved soft x-ray transient absorption spectrometer

A laser-based, table-top instrument is constructed to perform femtosecond soft x-ray transient absorption spectroscopy. Ultrashort soft x-ray pulses produced via high-order harmonic generation of the amplified output of a femtosecond Ti:sapphire laser system are used to probe atomic core-level transient absorptions in atoms and molecules. The results provide chemically specific, time-resolved dynamics with sub-50-fs time resolution. In this setup, high-order harmonics generated in a Ne-filled capillary waveguide are refocused by a gold-coated toroidal mirror into the sample gas cell, where the soft x-ray light intersects with an optical pump pulse. The transmitted high-order harmonics are spectrally dispersed with a home-built soft x-ray spectrometer, which consists of a gold-coated toroidal mirror, a uniform-line spaced plane grating, and a soft x-ray CCD camera. The optical layout of the instrument, design of the soft x-ray spectrometer, and spatial and temporal characterization of the high-order harmonics are described. Examples of static and time-resolved photoabsorption spectra collected on this apparatus are presented.
Date: May 21, 2008
Creator: Leone, Stephen; Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E. & Leone, Stephen R.
Object Type: Article
System: The UNT Digital Library