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Time-resolved Studies of Phase Transition Dynamics in Strongly Correlated Manganites (open access)

Time-resolved Studies of Phase Transition Dynamics in Strongly Correlated Manganites

Ultrafast light pulses can be used to control electronic, magnetic and structural phases of complex solids. Here, we investigate the dynamics of insulator-metal phase transitions in colossal magnetoresistive (CMR) manganites by a combination of femtosecond visible-to-midinfrared pump-probe techniques and transport measurements. We show that an insulator-metal transition can be stimulated in CMR manganites by both above bandgap excitation and selective excitation of individual vibrational degrees of freedom. These two approaches rely on the ultrafast manipulation of parameters controlling the electronic filling and the electronic bandwidth respectively, extending the concepts of filling and bandwidth control to the ultrafast timescale. The ultrafast vibrational control of correlated-electron phases may provide new insights into the role played by lattice vibrations in determining the electronic properties of complex solids.
Date: December 5, 2008
Creator: Rini, M.; Tobey, R.; Dean, N.; Wall, S.; Ehrke, H.; Zhu, Y. et al.
Object Type: Article
System: The UNT Digital Library
Modern Scientific Visualization is more than Just Pretty Pictures (open access)

Modern Scientific Visualization is more than Just Pretty Pictures

While the primary product of scientific visualization is images and movies, its primary objective is really scientific insight. Too often, the focus of visualization research is on the product, not the mission. This paper presents two case studies, both that appear in previous publications, that focus on using visualization technology to produce insight. The first applies"Query-Driven Visualization" concepts to laser wakefield simulation data to help identify and analyze the process of beam formation. The second uses topological analysis to provide a quantitative basis for (i) understanding the mixing process in hydrodynamic simulations, and (ii) performing comparative analysis of data from two different types of simulations that model hydrodynamic instability.
Date: December 5, 2008
Creator: Bethel, E Wes; Rubel, Oliver; Wu, Kesheng; Weber, Gunther; Pascucci, Valerio; Childs, Hank et al.
Object Type: Article
System: The UNT Digital Library
The complete genome sequence of Staphylothermus marinus reveals differences in sulfur metabolism among heterotrophic Crenarchaeota (open access)

The complete genome sequence of Staphylothermus marinus reveals differences in sulfur metabolism among heterotrophic Crenarchaeota

Staphylothermus marinus is an anaerobic, sulfur-reducing peptide fermenter of the archaeal phylum Crenarchaeota. It is the third heterotrophic, obligate sulfur reducing crenarchaeote to be sequenced and provides an opportunity for comparative analysis of the three genomes. The 1.57 Mbp genome of the hyperthermophilic crenarchaeote Staphylothermus marinus has been completely sequenced. The main energy generating pathways likely involve 2-oxoacid:ferredoxin oxidoreductases and ADP-forming acetyl-CoA synthases. S. marinus possesses several enzymes not present in other crenarchaeotes including a sodium ion-translocating decarboxylase likely to be involved in amino acid degradation. S. marinus lacks sulfur-reducing enzymes present in the other two sulfur-reducing crenarchaeotes that have been sequenced - Thermofilum pendens and Hyperthermus butylicus. Instead it has three operons similar to the mbh and mbx operons of Pyrococcus furiosus, which may play a role in sulfur reduction and/or hydrogen production. The two marine organisms, S. marinus and H. butylicus, possess more sodium-dependent transporters than T. pendens and use symporters for potassium uptake while T. pendens uses an ATP-dependent potassium transporter. T. pendens has adapted to a nutrient-rich environment while H. butylicus is adapted to a nutrient-poor environment, and S. marinus lies between these two extremes. The three heterotrophic sulfur-reducing crenarchaeotes have adapted to their habitats, terrestrial …
Date: September 5, 2008
Creator: Anderson, iain J.; Dharmarajan, Lakshmi; Rodriguez, Jason; Hooper, Sean; Porat, Iris; Ulrich, Luke E. et al.
Object Type: Article
System: The UNT Digital Library
Laboratory Investigations of a Low-Swirl Injector with H2 and CH4 at Gas Turbine Conditions (open access)

Laboratory Investigations of a Low-Swirl Injector with H2 and CH4 at Gas Turbine Conditions

Laboratory experiments were conducted at gas turbine and atmospheric conditions (0.101 < P{sub 0} < 0.810 MPa, 298 < T{sub 0} < 580K, 18 < U{sub 0} < 60 m/s) to characterize the overall behaviors and emissions of the turbulent premixed flames produced by a low-swirl injector (LSI) for gas turbines. The objective was to investigate the effects of hydrogen on the combustion processes for the adaptation to gas turbines in an IGCC power plant. The experiments at high pressures and temperatures showed that the LSI can operate with 100% H{sub 2} at up to {phi} = 0.5 and has a slightly higher flashback tolerance than an idealized high-swirl design. With increasing H{sub 2} fuel concentration, the lifted LSI flame begins to shift closer to the exit and eventually attaches to the nozzle rim and assumes a different shape at 100% H{sub 2}. The STP experiments show the same phenomena. The analysis of velocity data from PIV shows that the stabilization mechanism of the LSI remains unchanged up to 60% H{sub 2}. The change in the flame position with increasing H{sub 2} concentration is attributed to the increase in the turbulent flame speed. The NO{sub x} emissions show a log …
Date: March 5, 2008
Creator: Cheng, R. K.; Littlejohn, D.; Strakey, P.A. & Sidwell, T.
Object Type: Article
System: The UNT Digital Library
High Performance, Three-Dimensional Bilateral Filtering (open access)

High Performance, Three-Dimensional Bilateral Filtering

Image smoothing is a fundamental operation in computer vision and image processing. This work has two main thrusts: (1) implementation of a bilateral filter suitable for use in smoothing, or denoising, 3D volumetric data; (2) implementation of the 3D bilateral filter in three different parallelization models, along with parallel performance studies on two modern HPC architectures. Our bilateral filter formulation is based upon the work of Tomasi [11], but extended to 3D for use on volumetric data. Our three parallel implementations use POSIX threads, the Message Passing Interface (MPI), and Unified Parallel C (UPC), a Partitioned Global Address Space (PGAS) language. Our parallel performance studies, which were conducted on a Cray XT4 supercomputer and aquad-socket, quad-core Opteron workstation, show our algorithm to have near-perfect scalability up to 120 processors. Parallel algorithms, such as the one we present here, will have an increasingly important role for use in production visual analysis systems as the underlying computational platforms transition from single- to multi-core architectures in the future.
Date: June 5, 2008
Creator: Bethel, E. Wes
Object Type: Report
System: The UNT Digital Library
Plutonium Mobility Studies: 216-Z-9 Trench Sample Analysis Results (open access)

Plutonium Mobility Studies: 216-Z-9 Trench Sample Analysis Results

A variety of analyses were conducted on selected sediment samples collected from two wells (299 W15-46 and 299-W15-48) drilled near the 216-Z-9 Trench to elucidate the form and potential for Pu and Am to be mobilized under present conditions and those that could be expected in future remediation scenarios. Analyses included moisture content, determination of the less than sand size fraction (silt plus clay), carbon analysis, SEM/EDS analysis, microwave-assisted acid digestions for total element analysis, and extraction tests using Hanford groundwater as the leachate. Results of the extraction tests were used as input to conduct equilibrium geochemical modeling of the solutions with Geochemist’s Workbench®. Geochemical modeling results for Pu were evaluated in terms of recent conclusions regarding the solubility and redox reactions of Pu by Neck et al. (2007a, 2007b). It was found that the highest concentrations of Pu and Am were associated with sediments of low silt/clay content and occur above silt/clay rich layers within the sediment profile. It was also found that the Pu and Am were relatively enriched in the silt/clay portion of these samples. The fact that the highest concentrations of Pu and Am occurred in sediments with low silt/clay contents suggests that waste solutions had …
Date: September 5, 2008
Creator: Cantrell, Kirk J.; Geiszler, Keith N. & Arey, Bruce W.
Object Type: Report
System: The UNT Digital Library
Catalytic epoxidation of propene with H2O-O2 reactants on Au/TiO2 (open access)

Catalytic epoxidation of propene with H2O-O2 reactants on Au/TiO2

Au/TiO{sub 2} catalysts form hydroperoxy species from H{sub 2}O-O{sub 2} mixtures at near-ambient temperatures. These species can be used in the selective epoxidation of propene to propylene oxide.
Date: November 5, 2008
Creator: Ojeda, Manuel & Iglesia, Enrique
Object Type: Article
System: The UNT Digital Library
Metrics for the National SCADA Test Bed Program (open access)

Metrics for the National SCADA Test Bed Program

The U.S. Department of Energy Office of Electricity Delivery and Energy Reliability (DOE-OE) National SCADA Test Bed (NSTB) Program is providing valuable inputs into the electric industry by performing topical research and development (R&D) to secure next generation and legacy control systems. In addition, the program conducts vulnerability and risk analysis, develops tools, and performs industry liaison, outreach and awareness activities. These activities will enhance the secure and reliable delivery of energy for the United States. This report will describe metrics that could be utilized to provide feedback to help enhance the effectiveness of the NSTB Program.
Date: December 5, 2008
Creator: Craig, Philip A.; Mortensen, J. & Dagle, Jeffery E.
Object Type: Report
System: The UNT Digital Library
Evaluation of the Reproductive Success of Wild and Hatchery Steelhead in Hatchery and Natural and Hatchery Environments : Annual Report for 2008. (open access)

Evaluation of the Reproductive Success of Wild and Hatchery Steelhead in Hatchery and Natural and Hatchery Environments : Annual Report for 2008.

This report summarizes the field, laboratory, and analytical work from December 2007 through November 2008 on a research project that investigates interactions and comparative reproductive success of wild and hatchery origin steelhead (Oncorhynchus mykiss) trout in Forks Creek, a tributary of the Willapa River in southwest Washington. First, we continued to successfully sample hatchery and wild (i.e., naturally spawned) adult and wild smolt steelhead at Forks Creek. Second, we revealed microsatellite genotype data for adults and smolts through brood year 2008. Finally, four formal scientific manuscripts were published in 2008 and two are in press, one is in revision and two are in preparations.
Date: December 5, 2008
Creator: Quinn, Thomas P.; Seamons, todd; Hauser, Lorenz & Naish, Kerry
Object Type: Report
System: The UNT Digital Library
Beta-cell Assembly for the Quad Gas Sampling Detector (open access)

Beta-cell Assembly for the Quad Gas Sampling Detector

The beta-cells used in the beta-gamma detector have taken time to develop and to standardize the assembly of them. In making the assembly routine it is important to have step by step assembly instructions as well as a list of potential problems and their solutions. This document attempts to accomplish these goals.
Date: May 5, 2008
Creator: Cooper, Matthew W.; Bowyer, Ted W.; McIntyre, Justin I.; Hayes, James C.; Heimbigner, Tom R.; Ripplinger, Michael D. et al.
Object Type: Report
System: The UNT Digital Library
Design, Installation and Performance of the New insulator for NSTX CHI Experiments (open access)

Design, Installation and Performance of the New insulator for NSTX CHI Experiments

Coaxial Helicity Injection (CHI), a non-inductive method to initiate plasma and generate toroidal plasma current, is being investigated in the National Spherical Torus Experiment (NSTX). The center stack and outer vacuum vessel are separated by insulating gaps at the top and bottom of the slim central column so that a high voltage (up to 2 kV) can be applied between them from a pulsed power supply or a capacitor bank to initiate an arc discharge. In the presence of a suitable poloidal magnetic field, the discharge is initiated at the lower gap (the injector gap) and because of the strong toroidal field develops a helical structure resulting in substantial toroidal plasma current being driven. In NSTX, up to 390 kA of toroidal current has been generated for an injected current of 25 kA. The early investigations of CHI however frequently developed arcs across the insulator at the top of the machine (the absorber gap), which terminated the desired discharge. This arcing greatly restricted the operational space available for CHI studies. During 2002, the absorber region was modified to suppress these arcs. The new design includes a new ceramic insulator on the high field side of the absorber region with a …
Date: March 5, 2008
Creator: Mueller, D.; Chrzanowski, J.; Gates, D.; Menard, J.; Raman, R.; Jarboe, T. R. et al.
Object Type: Article
System: The UNT Digital Library
Transition Plan for the K-1203 Sewage Treatment Plant, East Tennessee Technology Park, Oak Ridge, Tennessee (open access)

Transition Plan for the K-1203 Sewage Treatment Plant, East Tennessee Technology Park, Oak Ridge, Tennessee

The K-1203 Sewage Treatment Plant (STP) was previously used to treat and process all sanitary sewage waste from the East Tennessee Technology Park (ETTP). The plant was shut down on May 29, 2008 as a result of the transition of sewage treatment for ETTP to the City of Oak Ridge. The City of Oak Ridge expanded the Rarity Ridge Sewage Treatment Plant (RRSTP) to include capacity to treat the waste from the ETTP and the Community Reuse Organization of East Tennessee (CROET) constructed a new ETTP lift station and force main to RRSTP. In preparation for the shutdown of K-1203, the US Department of Energy (DOE) in conjunction with Operation Management International (OMI) developed a shut down plan to outline actions that need to occur prior to the transition of the facility to Bechtel Jacob Company, LLC (BJC) for decontamination and demolition (D and D). This plan outlines the actions, roles, and responsibilities for BJC in order to support the transition of the K-1203 STP from OMI to the BJC Surveillance and Maintenance (S and M) and D and D programs. The D and D of the K-1203 Facilities is planned under the Comprehensive Environmental Response, Compensation, and Liability Act …
Date: October 5, 2008
Creator: J., Hoffmeister
Object Type: Report
System: The UNT Digital Library
A VUV photoionization measurement and ab-initio calculation of the ionization energy of gas phase SiO2 (open access)

A VUV photoionization measurement and ab-initio calculation of the ionization energy of gas phase SiO2

In this work we report on the detection and vacuum-ultraviolet (VUV) photoionization of gas phase SiO2 generated in situ via laser ablation of silicon in a CO2 molecular beam. The resulting species are investigated by single photon ionization with tunable VUV synchrotron radiation and mass analyzed using reflectron mass spectrometry. Photoionization efficiency (PIE) curves are recorded for SiO and SiO2 and ionization energy estimates are revealed from such measurements. A state-to-state ionizationenergy of 12.60 (+-0.05) eV is recorded by fitting two prominent peaks in the PIE curve for the following process: 1SUM O-Si-O --> 2PRODg [O-Si-O]+. Electronic structure calculations aid in the interpretation of the photoionization process and allow for identification of the symmetric stretch of 2PRODg [O-Si-O]+ which is observed in the PIE spectrum to be 0.11 eV (890 cm-1) above the ground state of the cation and agrees with the 892 cm-1 symmetric stretch frequency calculated at the CCSD(T)/aug-cc-pVTZ level.
Date: December 5, 2008
Creator: Kostko, Oleg; Ahmed, Musahid & Metz, Ricardo B.
Object Type: Article
System: The UNT Digital Library
Molecular Surface Chemistry by Metal Single Crystals and Nanoparticles from Vacuum to High Pressure. (open access)

Molecular Surface Chemistry by Metal Single Crystals and Nanoparticles from Vacuum to High Pressure.

Model systems for studying molecular surface chemistry have evolved from single crystal surfaces at low pressure to colloidal nanoparticles at high pressure. Low pressure surface structure studies of platinum single crystals using molecular beam surface scattering and low energy electron diffraction techniques probe the unique activity of defects, steps and kinks at the surface for dissociation reactions (H-H, C-H, C-C, O{double_bond}O bonds). High-pressure investigations of platinum single crystals using sum frequency generation vibrational spectroscopy have revealed the presence and the nature of reaction intermediates. High pressure scanning tunneling microscopy of platinum single crystal surfaces showed adsorbate mobility during a catalytic reaction. Nanoparticle systems are used to determine the role of metal-oxide interfaces, site blocking and the role of surface structures in reactive surface chemistry. The size, shape and composition of nanoparticles play important roles in determining reaction activity and selectivity.
Date: April 5, 2008
Creator: Somorjai, Gabor A. & Park, Jeong Y.
Object Type: Article
System: The UNT Digital Library
Thermodynamic Characterization of Mexico City Aerosol during MILAGRO 2006 (open access)

Thermodynamic Characterization of Mexico City Aerosol during MILAGRO 2006

Fast measurements of aerosol and gas-phase constituents coupled with the ISORROPIA-II thermodynamic equilibrium model are used to study the partitioning of semivolatile inorganic species and phase state of Mexico City aerosol sampled at the T1 site during the MILAGRO 2006 campaign. Overall, predicted semivolatile partitioning agrees well with measurements. PM{sub 2.5} is insensitive to changes in ammonia but is to acidic semivolatile species. For particle sizes up to 1 {micro}m diameter, semi-volatile partitioning requires 30-60 min to equilibrate; longer time is typically required during the night and early morning hours. When the aerosol sulfate-to-nitrate molar ratio is less than unity, predictions improve substantially if the aerosol is assumed to follow the deliquescent phase diagram. Treating crustal species as 'equivalent sodium' (rather than explicitly) in the thermodynamic equilibrium calculations introduces important biases in predicted aerosol water uptake, nitrate and ammonium; neglecting crustals further increases errors dramatically. This suggests that explicitly considering crustals in the thermodynamic calculations is required to accurately predict the partitioning and phase state of aerosols.
Date: December 5, 2008
Creator: Fountoukis, C.; Nenes, A.; Sullivan, A.; Weber, R.; VanReken, T.; Fischer, M. et al.
Object Type: Article
System: The UNT Digital Library
Development of a New Stratigraphic Trap Exploration Using Elastic-Wave Seismic Technology (open access)

Development of a New Stratigraphic Trap Exploration Using Elastic-Wave Seismic Technology

Vecta acquired 9 square miles of 9-C seismic data in Mountrail County, North Dakota with the Mission Canyon shoreline as a primary target. Vecta contracted the Institute Francais du Petrole in order to co-develop a more rigorous multicomponent seismic interpretation product. The final interpretation was very unique in that it utilized not only the 9-C seismic data but also the new jointly developed software. A Mission Canyon anomaly was developed in 2006; however, it was of insufficient size to be a commercial target at the time. Therefore, Vecta analyzed the shear data for anisotropy within the Bakken formation and successfully reentered an abandoned producer within the project area and drilled a horizontal leg through the anomalous zones of the middle member of the Bakken formation. The well was open hole completed, swab tested, sand fraced, and swab tested some more. No shows of oil were ever seen from the Bakken formation, but the well yielded considerable amounts of formation water. The well has been abandoned as non-commercial. From the swab tests, one may conclude considerable permeability exists in the formation, thus confirming the utility of the shear wave to detect fractures within the targeted formation.
Date: February 5, 2008
Creator: DeVault, Bryan
Object Type: Report
System: The UNT Digital Library
Imaging with Mass Spectrometry: A SIMS and VUV-Photoionization Study of Ion-Sputtered Atoms and Clusters from GaAs and Au (open access)

Imaging with Mass Spectrometry: A SIMS and VUV-Photoionization Study of Ion-Sputtered Atoms and Clusters from GaAs and Au

A new mass spectrometry surface imaging method is presented in which ion-sputtered neutrals are postionized by wavelength-tunable vacuum ultraviolet (VUV) light from a synchrotron source. Mass spectra and signal counts of the photoionized neutrals from GaAs (100) and Au are compared to those of the secondary ions. While clusters larger than dimers are more efficiently detected as secondary ions, certain species, such as As2, Au and Au2, are more efficiently detected through the neutral channel. Continuously tuning the photon wavelength allows photoionization efficiency (PIE) curves to be obtained for sputtered Asm (m=1,2) and Aun (n=1-4). From the observed ionization thresholds, sputtered neutral As and Au show no clear evidence of electronic excitation, while neutral clusters have photoionization onsets shifted to lower energies by ~;;0.3 eV. These shifts are attributed to unresolved vibrational and rotational excitations. High-spatial resolution chemical imaging with synchrotron VUV postionization is demonstrated at two different photon energies using a copper TEM grid embedded in indium. The resulting images are used to illustrate the use of tunable VUV light for verifying mass peak assignments by exploiting the unique wavelength-dependent PIE of each sputtered neutral species. This capability is valuable for identifying compounds when imaging chemically complex systems with …
Date: December 5, 2008
Creator: Takahashi, Lynelle; Zhou, Jia; Wilson, Kevin R.; Leone, Stephen R. & Ahmed, Musahid
Object Type: Article
System: The UNT Digital Library
Rapid Response Small Machining NNR Project 703025 (open access)

Rapid Response Small Machining NNR Project 703025

This project was an effort to develop a machining area for small sized parts that is capable of delivering product with a quick response time. This entailed focusing efforts on leaning out specific work cells that would result in overall improvement to the entire machining area. This effort involved securing the most efficient available technologies for these areas. In the end, this incorporated preparing the small machining area for transformation to a new facility.
Date: December 5, 2008
Creator: Kanies, Tim
Object Type: Report
System: The UNT Digital Library
Air Conditioner Compressor Performance Model (open access)

Air Conditioner Compressor Performance Model

During the past three years, the Western Electricity Coordinating Council (WECC) Load Modeling Task Force (LMTF) has led the effort to develop the new modeling approach. As part of this effort, the Bonneville Power Administration (BPA), Southern California Edison (SCE), and Electric Power Research Institute (EPRI) Solutions tested 27 residential air-conditioning units to assess their response to delayed voltage recovery transients. After completing these tests, different modeling approaches were proposed, among them a performance modeling approach that proved to be one of the three favored for its simplicity and ability to recreate different SVR events satisfactorily. Funded by the California Energy Commission (CEC) under its load modeling project, researchers at Pacific Northwest National Laboratory (PNNL) led the follow-on task to analyze the motor testing data to derive the parameters needed to develop a performance models for the single-phase air-conditioning (SPAC) unit. To derive the performance model, PNNL researchers first used the motor voltage and frequency ramping test data to obtain the real (P) and reactive (Q) power versus voltage (V) and frequency (f) curves. Then, curve fitting was used to develop the P-V, Q-V, P-f, and Q-f relationships for motor running and stalling states. The resulting performance model ignores the …
Date: September 5, 2008
Creator: Lu, Ning; Xie, YuLong & Huang, Zhenyu
Object Type: Report
System: The UNT Digital Library
Preserving Nuclear Grade Knowledge (open access)

Preserving Nuclear Grade Knowledge

When people think of the government they think of the President, or Congress, or the Internal Revenue Service (IRS), but there are thousands of people in government-related jobs doing things most don’t really notice everyday. You can find them everywhere, from the space science folks at NASA, to the Federal Bureau of Investigations (FBI) watching out for the bad guys. There are Rangers, and Social Workers, Nurses and Agricultural Managers. They are people working to keep the many facets of the USA rolling. One very diverse bunch is The Department of Energy (DOE) , a group who is expanding the ways we make and save energy to power our cars, homes, and businesses. Tucked away under the DOE is the National Nuclear Security Administration, the NNSA is an agency that maintains the safety, security, and reliability of the U.S. nuclear weapons stockpile. It works to reduce global danger from weapons of mass destruction. It provides the U.S. Navy with safe nuclear propulsion, and it responds to nuclear and radiological emergencies in the United States and abroad, and it supports efforts in science and technology*. (* DOE/NNSA/KCP website info)
Date: February 5, 2008
Creator: Lange, Bob
Object Type: Article
System: The UNT Digital Library
Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons (open access)

Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons

The reactions of the methylidyne radical (CH) with ethylene, acetylene, allene, and methylacetylene are studied at room temperature using tunable vacuum ultraviolet (VUV) photoionization and time-resolved mass spectrometry. The CH radicals are prepared by 248 nm multiphoton photolysis of CHBr3 at 298 K and react with the selected hydrocarbon in a helium gas flow. Analysis of photoionization efficiency versus VUV photon wavelength permits isomer-specific detection of the reaction products and allows estimation of the reaction product branching ratios. The reactions proceed by either CH insertion or addition followed by H atom elimination from the intermediate adduct. In the CH + C2H4 reaction the C3H5 intermediate decays by H atom loss to yield 70(+-8)percent allene, 30(+-8)percent methylacetylene and less than 10percent cyclopropene, in agreement with previous RRKM results. In the CH + acetylene reaction, detection of mainly the cyclic C3H2 isomer is contrary to a previous RRKM calculation that predicted linear triplet propargylene to be 90percent of the total H-atom co-products. High-level CBS-APNO quantum calculations and RRKM calculation for the CH + C2H2 reaction presented in this manuscript predict a higher contribution of the cyclic C3H2 (27.0percent) versus triplet propargylene (63.5percent) than these earlier predictions. Extensive calculations on the C3H3 and …
Date: December 5, 2008
Creator: Goulay, Fabien; Trevitt, Adam J.; Meloni, Giovanni; Selby, Talitha M.; Osborn, David L.; Taatjes, Craig A. et al.
Object Type: Article
System: The UNT Digital Library
"Workshop to Promote and Coordinate U.S.A. Contributions to AMMA on Land Surface, Water Cycle, Aerosol and Radiation Budget Issues". (open access)

"Workshop to Promote and Coordinate U.S.A. Contributions to AMMA on Land Surface, Water Cycle, Aerosol and Radiation Budget Issues".

RIMS ID: ER64245-1028054-0012347 Consistent with the original proposal (dated February 28, 2006), the grant supported the participation in the above Workshop of a diverse group of West African, British, and American atmospheric scientists. All of these individuals contributed strongly to Workshop, with the result that ARM’s involvement in and contribution to AMMA was enhanced with respect to land surface, water cycle, aerosol, and radiation issues. Also, the Workshop gave these participants early exposure to ARM’s 2007 CLASIC Campaign over the U.S. Southern Great Plains, which is addressing parts of the same problem complex. The following eight individuals were fully funded (complete airfare, accommodations, registration, meals) to participate in the Workshop -- Dr. Aiguo Dai (NCAR, USA), Dr. Adamou Ousmane Manga (University of Niamey, Niger), Professor Abdelkrim Ben Mohamed (University of Niamey, Niger), Dr. Gary Robinson (University of Reading, UK), Dr. Amadou Gaye (University of Dakar, Senegal), Dr. Anne Jefferson (NOAA, USA), Dr. Aondover Tarhule (University of Oklahoma, USA), and Dr. Sally McFarlane (Pacific Northwest National Laboratory, USA). Partial funding also was provided for Professor Peter Lamb (University of Oklahoma, USA). To deepen the involvement of ARM in AMMA, the grant also paid for participation in the AMMA Special Observing Period …
Date: May 5, 2008
Creator: Lamb, Peter
Object Type: Report
System: The UNT Digital Library
CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS (open access)

CHEMICAL SAFETY: ASKING THE RIGHT QUESTIONS

Recent reports have shown that, despite efforts to the contrary, chemical accidents continue to occur at an unacceptable rate and there is no evidence that this rate is decreasing. Based on this observation, one can conclude that previous analyses have not accurately identified and implemented appropriate fixes to eliminate identified root causes for chemical events. Based on this, it is time to reevaluate chemical accident data with a fresh eye and determine (a) what corrective actions have already been identified but have not been implemented, (b) what other root causes may be involved, and (c) what new corrective actions should be taken to eliminate these newly identified root causes.
Date: August 5, 2008
Creator: Simmons, F
Object Type: Article
System: The UNT Digital Library
Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States (open access)

Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States

When direct reactions populate highly excited, unbound configurations in the residual nucleus, the nucleus may further evolve into a compound nucleus. Alternatively, the residual system may decay by emitting particles into the continuum. Understanding the relative weights of these two processes as a function of the angular momentum and parity deposited in the nucleus is important for the surrogate-reaction technique. A particularly interesting case is compound-nucleus formation via the (d, p) reaction, which may be a useful tool for forming compound nuclei off the valley of stability in inverse-kinematics experiments. We present here a study of the compound formation probability for a closely-related direct reaction, direct-semidirect radiative neutron capture.
Date: February 5, 2008
Creator: Dietrich, F S
Object Type: Article
System: The UNT Digital Library