Language

1 Outreach, Education and Domestic Market Enhancement 2 Export Promotion and Assistance (open access)

1 Outreach, Education and Domestic Market Enhancement 2 Export Promotion and Assistance

Geothermal Energy Association supports the US geothermal industry in its efforts to bring more clean geothermal energy on-line throughout the world. Activities designed to accomplish this goal include: (1) developing and maintaining data bases, web pages, (2) commissioning of special studies and reports, (3) preparing, printing and distributing brochures and newsletters, (4) developing exhibits and displays, and participating in trade shows, (5) designing, producing and disseminating audio-video materials, (6) monitoring and coordinating programs carried out by US DOE and other Federal agencies, (7) holding workshops to facilitate communication between researchers and industry and to encourage their recognition of emerging markets for geothermal technology, (8) attending conferences, making speeches and presentation, and otherwise interacting with environmental and other renewable energy organizations and coalitions, (9) hosting events in Washington, DC and other appropriate locations to educate Federal, State and local representatives, environmental groups, the news media, and other about the status and potential of geothermal energy, (10) conducting member services such as the preparation and distribution of a member newsletter related to operating and maintaining s useful and viable association, and (11) performing similar kinds of activities designed to inform others about geothermal energy. The activities of the export promotion aim to …
Date: March 15, 2004
Creator: Geothermal Energy Association
Object Type: Report
System: The UNT Digital Library
A 20-year data set of surface longwave fluxes in the Arctic (open access)

A 20-year data set of surface longwave fluxes in the Arctic

Creation of 20-year data set of surface infrared fluxes from satellite measurements. A reliable estimate of the surface downwelling longwave radiation flux (DLF) is a glaring void in available forcing data sets for models of Arctic sea ice and ocean circulation. We have developed a new method to estimate the DLF from a combination of satellite sounder retrievals and brightness temperatures from the TIROS Operational Vertical Sounder (TOVS), which has flown on NOAA polar-orbiting satellites continuously since late 1979. The overarching goal of this project was to generate a 20-year data set of surface downwelling longwave flux measurements from TOVS data over the Arctic Ocean. Daily gridded fields of DLF were produced with a spatial resolution of (100 km){sup 2} north of 60{sup o}N for 22.5 years rather than only 20. Surface measurements from the field station at Barrow, AK--part of the Atmospheric Radiation Measurement (ARM) Program --and from the Surface Heat Budget of the Arctic (SHEBA) were used to validate the satellite-derived fluxes and develop algorithm improvements for conditions that had resulted in systematic errors in early versions of the algorithm. The resulting data set has already been sent to two other investigators for incorporation into their research, and …
Date: June 15, 2004
Creator: Francis, Jennifer
Object Type: Report
System: The UNT Digital Library
2003 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313 (open access)

2003 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

None
Date: December 15, 2004
Creator: Stockton, M.
Object Type: Report
System: The UNT Digital Library
Accessing High Pressure States Relevant to Core Conditions in the Giant Planets (open access)

Accessing High Pressure States Relevant to Core Conditions in the Giant Planets

We have designed an experimental technique to use on the National Ignition Facility (NIF) laser to achieve very high pressure (P{sub max} > 10 Mbar = 1000 GPa), dense states of matter at moderate temperatures (kT < 0.5 eV = 6000 K), relevant to the core conditions of the giant planets. A discussion of the conditions in the interiors of the giant planets is given, and an experimental design that can approach those conditions is described.
Date: April 15, 2004
Creator: Remington, B. A.; Cavallo, R. M.; Edwards, M. J.; Ho, D. D.; Lorenz, K. T.; Lorenzana, H. E. et al.
Object Type: Article
System: The UNT Digital Library
Acquisition of time-lapse, 6-component, P- and S-wave, crosswell seismic survey with orbital vibrator and of time-lapse VSP for CO2 injection monitoring (open access)

Acquisition of time-lapse, 6-component, P- and S-wave, crosswell seismic survey with orbital vibrator and of time-lapse VSP for CO2 injection monitoring

Using an orbital vibrator source (2-components), and a 40 level 3-component geophone string, a 6-component crosswell survey was acquired before and after a CO2 injection in a saline aquifer. Decomposition of the two source components and component rotation of both source and sensors created good separation of P- and S-wave energy allowing independent analysis of travel time and reflectivity. A time-lapse VSP was also acquired.
Date: July 15, 2004
Creator: Daley, Tom; Daley, T. M.; Myer, L. R. & Majer, E. L.
Object Type: Article
System: The UNT Digital Library
Active Well Neutron Coincidence Assays for U-235 Content in HB-Line Desicooler Repackage Campaign at the Savannah River Site (open access)

Active Well Neutron Coincidence Assays for U-235 Content in HB-Line Desicooler Repackage Campaign at the Savannah River Site

At HB-Line of the Savannah River Site, 4.3 kg of U-235 have been repackaged from FB-Line Desicooler material into a cement matrix in individual one-gallon paint cans for disposition as solid waste. The 4.3 kg of U-235 material were packaged into 172 paint cans with U-235 contents ranging from 8.9 g up to 32 g. Prior to transfer to the Solid Waste Facilities, verification measurements of selected cans were performed to assure valid control of the solid waste. The HB-Line-DOE Sampling Plan designated confirmatory assays, and a total of 67 paint cans were assayed to verify the contents. The Analytical Development Section of the Savannah River National Laboratory selected an active well coincidence neutron counter as the best instrument available to accomplish the assays. The instrument was set up at-line in the thermal excitation mode, and three standard samples that contained 8.9-, 28.5-, and 32.4-g of U-235 were counted for twenty hours of acquisition time each. A linear calibration based on the observed doubles rates was installed in the instrument. Subsequent verification measurements were performed on the selected samples using fifteen one-minute active acquisitions. Of the 67 samples assayed, 53 verification measurements were within the limits greater than or less …
Date: July 15, 2004
Creator: DEWBERRY, RAYMOND
Object Type: Article
System: The UNT Digital Library
Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors (Workshop Report) (open access)

Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors (Workshop Report)

The ''Workshop on Advanced Computational Materials Science: Application to Fusion and Generation IV Fission Reactors'' was convened to determine the degree to which an increased effort in modeling and simulation could help bridge the gap between the data that is needed to support the implementation of these advanced nuclear technologies and the data that can be obtained in available experimental facilities. The need to develop materials capable of performing in the severe operating environments expected in fusion and fission (Generation IV) reactors represents a significant challenge in materials science. There is a range of potential Gen-IV fission reactor design concepts and each concept has its own unique demands. Improved economic performance is a major goal of the Gen-IV designs. As a result, most designs call for significantly higher operating temperatures than the current generation of LWRs to obtain higher thermal efficiency. In many cases, the desired operating temperatures rule out the use of the structural alloys employed today. The very high operating temperature (up to 1000 C) associated with the NGNP is a prime example of an attractive new system that will require the development of new structural materials. Fusion power plants represent an even greater challenge to structural materials …
Date: July 15, 2004
Creator: Stoller, RE
Object Type: Report
System: The UNT Digital Library
Affordable Window Insulation with R-10/inch Rating (open access)

Affordable Window Insulation with R-10/inch Rating

During the performance of contract DE-FC26-00-NT40998, entitled ''Affordable Window Insulation with R-10/inch Value'', research was conducted at Aspen Aerogels, Inc. to develop new transparent aerogel materials suitable for window insulation applications. The project requirements were to develop a formulation or multiple formulations that have high transparency (85-90%) in the visible region, are hydrophobic (will not opacify with exposure to water vapor or liquid), and have at least 2% resiliency (interpreted as recoverable 2% strain and better than 5% strain to failure in compression). Results from an unrelated project showed that silica aerogels covalently bonded to organic polymers exhibit excellent mechanical properties. At the outset of this project, we believed that such a route is the best to improve mechanical properties. We have applied Design of Experiment (DOE) techniques to optimize formulations including both silica aerogels and organically modified silica aerogels (''Ormosils''). We used these DOE results to optimize formulations around the local/global optimization points. This report documents that we succeeded in developing a number of formulations that meet all of the stated criteria. We successfully developed formulations utilizing a two-step approach where the first step involves acid catalyzed hydrolysis and the second step involves base catalyzed condensation to make the …
Date: October 15, 2004
Creator: Begag, Jenifer Marchesi Redouane; Lee, Je Kyun; Ou, Danny; Sonn, Jong Ho; Gould, George & Rhine, Wendell
Object Type: Report
System: The UNT Digital Library
Aging, tumor suppression and cancer: High-wire act! (open access)

Aging, tumor suppression and cancer: High-wire act!

Evolutionary theory holds that aging is a consequence of the declining force of natural selection with age. We discuss here the evidence that among the causes of aging in complex multicellular organisms, such as mammals, is the antagonistically pleiotropic effects of the cellular responses that protect the organism from cancer. Cancer is relatively rare in young mammals, owing in large measure to the activity of tumor suppressor mechanisms. These mechanisms either protect the genome from damage and/or mutations, or they elicit cellular responses--apoptosis or senescence--that eliminate or prevent the proliferation of somatic cells at risk for neoplastic transformation.We focus here on the senescence response, reviewing its causes, regulation and effects. In addition, we describe recent data that support the idea that both senescence and apoptosis may indeed be the double-edged swords predicted by the evolutionary hypothesis of antagonistic pleiotropy--protecting organisms from cancer early in life, but promoting aging phenotypes, including late life cancer, in older organisms.
Date: August 15, 2004
Creator: Campisi, Judith
Object Type: Article
System: The UNT Digital Library
Alternative Conceptual Model for Colloid Generation from Commercial Spent Nuclear Fuel (open access)

Alternative Conceptual Model for Colloid Generation from Commercial Spent Nuclear Fuel

Colloids have the potential to transport strongly sorbing radionuclide contaminants in soils and groundwater aquifers. Recent studies from the Nevada Test Site have indicated the enhanced mobility plutonium, albeit in minute quantities, associated with various silicate minerals (Kersting et al., 1999); however, significant colloidal transport of thorium (Th) and rare earths (RE) in nature, considered to be chemical analogs for plutonium, is rare. Yet, the current Yucca Mountain model for colloids would have predicted extensive Th- and RE migration, given these phases' association with clay minerals. Several studies have pointed to the effect of water flow rate on colloid and particulate migration. In this paper, we examine the benefit of relating water flow rate and the wasteform alteration structure to colloid release.
Date: February 15, 2004
Creator: Buck, Edgar C.; McNamara, Bruce K. & Hanson, Brady D.
Object Type: Report
System: The UNT Digital Library
Analysis of IECC2003 Chiller Heat Recovery for Service Water Heating Requirement for New York State (open access)

Analysis of IECC2003 Chiller Heat Recovery for Service Water Heating Requirement for New York State

The state of New York asked the U.S. Department of Energy to evaluate the cost-effectiveness of the requirement for Heat Recovery for Service Water Heating that exists in the 2003 International Energy Conservation Code to determine whether this requirement should be adopted into the New York State Energy Code. A typical hotel application that would trigger this requirement was examined using whole building simulation software to generate baseline annual chiller and service hot water loads, and a spreadsheet was used to examine the energy savings potential for heat recovery using hourly load files from the simulation. An example application meeting the code requirement was developed, and the energy savings, energy cost savings, and first costs for the heat recovery installation were developed. The calculated payback for this application was 6.3 years using 2002 New York state average energy costs. This payback met the minimum requirements for cost effectiveness established for the state of New York for updating the commercial energy conservation code.
Date: August 15, 2004
Creator: Winiarski, David W.
Object Type: Report
System: The UNT Digital Library
ANALYSIS OF TWO-PHASE FLOW MODELS WITH TWO MOMENTUM EQUATIONS. (open access)

ANALYSIS OF TWO-PHASE FLOW MODELS WITH TWO MOMENTUM EQUATIONS.

An analysis of the standard system of differential equations describing multi-speed flows of multi-phase media is performed. It is proved that the Cauchy problem, as posed in most best-estimate thermal-hydraulic codes, results in unstable solutions and potentially unreliable description of many physical phenomena. A system of equations, free from instability effects, is developed allowing more rigorous numerical modeling.
Date: March 15, 2004
Creator: KROSHILIN,A. E. KROSHILIN,V. E. KOHUT,P.
Object Type: Article
System: The UNT Digital Library
Analytic Expressions for the Angular Resolution of Compton Gamma-ray Detectors (open access)

Analytic Expressions for the Angular Resolution of Compton Gamma-ray Detectors

This paper describes the derivation of analytic expressions for the angular resolution of reconstructing gamma rays detected via Compton interactions. We consider two types of gamma-ray detectors: Compton-ring and electron-tracking devices. In Compton-ring devices, the direction of the scattered electron is not resolved, only the total energy (electron and scattered photon) and the scattered photon direction are measured. The measured quantities define a cone about the axis of the scattered photon direction. The initial photon direction lies along this cone. Thus for single events there is a ring-like ambiguity in the photon direction. By combining multiple events, the intersection of the reconstructed rings will resolve the initial direction of the photon source. In this paper, we derive the resolution of the cone angle for individual rings. Electron-tracking type devices resolve the electron path. Although the scattered electron subsequently undergoes multiple-Coulomb scattering, it is possible to measure the initial electron direction with sufficiently high tracking resolution. By measuring the direction and energy of the electron and the direction of the scattered photon, the initial photon direction can be uniquely determined. The challenge for this type of detector is achieving the high tracking resolution. In Section 2 we derive the well-known Compton …
Date: January 15, 2004
Creator: Wright, D M
Object Type: Report
System: The UNT Digital Library
Anisotropic Flow at RHIC. (open access)

Anisotropic Flow at RHIC.

We present the first measurement of directed flow (v{sub 1}) at the Relativistic Heavy Ion Collider (RHIC). v{sub 1} is found to be consistent with zero at pseudorapidities {eta} from -1.2 to 1.2, then rises to the level of a couple of percent over the range 2.4 < |{eta}| < 4. The latter observation is similar to that from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. We studied the evolution of elliptic flow from p + p collisions through d + Au collision, and onto Au + Au collisions. Measurements of higher harmonics are presented and discussed.
Date: March 15, 2004
Creator: Tang, A. H.
Object Type: Article
System: The UNT Digital Library
Assessment of Various Kinetic Models for the Pyrolysis of a Microgranular Cellulose (open access)

Assessment of Various Kinetic Models for the Pyrolysis of a Microgranular Cellulose

The kinetics of pyrolysis of a micro-crystalline cellulose in nitrogen were studied from TGA and DTG data, obtained with two different modes of heating: a dynamic mode at constant heating rates between 1 and 11 C/min and an isothermal mode at various temperatures, kept constant between 280 and 320 C. In isothermal mode, it appeared very clearly that the mass depletion shows a sigmoid profile characteristic of an auto-accelerated reaction process. This behavior is consistent with kinetics of nuclei-growth, well represented by the models of Avrami-Erofeev and of Prout-Tompkins type. All the other kinetic models commonly applied to the thermal decomposition of solids revealed unsatisfactory. The TGA and DTG data were thus found ideally simulated from a reaction scheme consisting in two parallel reactions, termed 1 and 2, each one described by the kinetic law: DX/DT = -A{sup -E/RT}x{sup n}(1-0.99x){sup n}. Reaction 1 is related to the bulk decomposition of cellulose and is characterized by the set of parameters: E{sub 1}= 202 kJ/mole; n{sub 1}=1; m{sub 1}=0.48. Reaction 2 is related to the slower residual decomposition, which takes place over approximately 350 C and affects only 16 % by weight of the raw cellulose. With m{sub 2} constrained to 1, …
Date: January 15, 2004
Creator: Burnham, A K; Capart, R & Khezami, L
Object Type: Article
System: The UNT Digital Library
Atoms for Peace after Fifty Years (open access)

Atoms for Peace after Fifty Years

President Eisenhower's hopes for nuclear technology still resonate, but the challenges to fulfilling them are much different today. On December 8, 1953, President Eisenhower, returning from his meeting with the leaders of Britain and France at the Bermuda Summit, flew directly to New York to address the United Nations General Assembly. His presentation, known afterwards as the ''Atoms for Peace'' speech, was bold, broad, and visionary. Eisenhower highlighted dangers associated with the further spread of nuclear weapons and the end of the thermonuclear monopoly, but the president also pointed to opportunities. Earlier that year, Stalin had died and the Korean War armistice was signed. Talks on reunification of Austria were about to begin. The speech sought East-West engagement and outlined a framework for reducing nuclear threats to security while enhancing the civilian benefits of nuclear technology. One specific proposal offered to place surplus military fissile material under the control of an ''international atomic energy agency'' to be used for peaceful purposes, especially economic development. Eisenhower clearly recognized the complex interrelationships between different nuclear technologies and the risks and the benefits that accrue from each. The widespread use of civilian nuclear technology and absence of any use of a nuclear weapon …
Date: March 15, 2004
Creator: Joeck, N; Lehman, R; Vergino, E & Schock, R
Object Type: Article
System: The UNT Digital Library
An Automated System for Measuring Microphysical and Radiative Cloud Characteristics from a Tethered Balloon (open access)

An Automated System for Measuring Microphysical and Radiative Cloud Characteristics from a Tethered Balloon

OAK-B135 The rate of climate change in polar regions is now felt to be a harbinger of possible global warming. Long-lived, relatively thin stratus clouds play a predominant role in transmitting solar radiation and trapping long wave radiation emitted from open water and melt ponds. In situ measurements of microphysical and radiative properties of Arctic and Antarctic stratus clouds are needed to validate retrievals from remote measurements and simulations using numerical models. While research aircraft can collect comprehensive microphysical and radiative data in clouds, the duration of these aircraft is relatively short (up to about 12 hours). During the course of the Phase II research, a tethered balloon system was developed that supports miniaturized meteorological, microphysical and radiation sensors that can collect data in stratus clouds for days at a time. The tethered balloon system uses a 43 cubic meter balloon to loft a 17 kg sensor package to altitudes u p to 2 km. Power is supplied to the instrument package via two copper conductors in the custom tether. Meteorological, microphysical and radiation data are recorded by the sensor package. Meteorological measurements include pressure, temperature, humidity, wind speed and wind direction. Radiation measurements are made using a 4-pi radiometer …
Date: March 15, 2004
Creator: Lawson, Dr. Paul
Object Type: Report
System: The UNT Digital Library
Automating Shallow Seismic Imaging (open access)

Automating Shallow Seismic Imaging

This report covers a one-year, no-cost extension that was requested and received in 2003; the extension runs through September 14, 2004. The extension has been used to continue data analysis and prepare additional manuscripts for submission to refereed journals. The primary research focus of the original three-year period of funding was to develop and demonstrate an automated method of conducting two-dimensional (2D) shallow-seismic surveys with the goal of saving time, effort, and money. Tests involving the second generation of the hydraulic geophone-planting device dubbed the ''Autojuggie'' showed that large numbers of geophones can be placed quickly and automatically and can acquire high-quality data, although not under all conditions (please see the Status and Results of Experiments sections for details). In some easy-access environments, this device could make shallow seismic surveying considerably more efficient and less expensive. The most recent research analyzed the difference in seismic response of the geophones with variable geophone spike length and geophones attached to various steel media. Experiments investigated the azimuthal dependence of the quality of data relative to the orientation of the rigidly attached geophones. Other experiments designed to test the hypothesis that the data are being amplified in much the same way that an …
Date: June 15, 2004
Creator: Steeples, Don W.
Object Type: Report
System: The UNT Digital Library
Axisymmetric Tandem Mirrors: Stabilization and Confinement Studies (open access)

Axisymmetric Tandem Mirrors: Stabilization and Confinement Studies

The 'Kinetic Stabilizer' has been proposed as a means of MHD stabilizing an axisymmetric tandem mirror system. The K-S concept is based on theoretical studies by Ryutov, confirmed experimentally in the Gas Dynamic Trap experiment in Novosibirsk. In the K-S beams of ions are directed into the end of an 'expander' region outside the outer mirror of a tandem mirror. These ions, slowed, stagnated, and reflected as they move up the magnetic gradient, produce a low-density stabilizing plasma. At the Lawrence Livermore National Laboratory we have been conducting theoretical and computational studies of the K-S Tandem Mirror. These studies have employed a low-beta code written especially to analyze the beam injection/stabilization process, and a new code SYMTRAN (by Hua and Fowler) that solves the coupled radial and axial particle and energy transport in a K-S TM. Also, a 'legacy' MHD stability code, FLORA, has been upgraded and employed to benchmark the injection/stabilization code and to extend its results to high beta values. The FLORA code studies so far have confirmed the effectiveness of the K-S in stabilizing high-beta (40%) plasmas with stabilizer plasmas the peak pressures of which are several orders of magnitude smaller than those of the confined plasma. …
Date: July 15, 2004
Creator: Post, R F; Fowler, T K; Bulmer, R; Byers, J; Hua, D & Tung, L
Object Type: Article
System: The UNT Digital Library
Benson Beach Demonstration Project: Composition and Abundance of Biota at Three Alternative Sump Sites (open access)

Benson Beach Demonstration Project: Composition and Abundance of Biota at Three Alternative Sump Sites

The Portland District of the U.S. Army Corps of Engineers is investigating plans to provide sediment to nourish beaches north of the Mouth of the Columbia River (MCR). Under the currently designed proposal, sediment dredged from the MCR will be temporarily stored at one of three proposed areas south of the North Jetty before being redredged and moved by a cutterhead pipeline dredge over the jetty to nourish Benson Beach. Resulting potential impacts to resident Dungeness crab (Cancer magister) and fishes represent one of the criteria for evaluating each of the alternative locations. To establish the species composition and relative abundance of crabs and fishes associated with each of the three proposed sump areas, researchers from the Pacific Northwest National Laboratory Marine Sciences Division completed nine field sampling trips from July 8, 2003, to November 1, 2003, for a total of 113 successful trawls comprising an area of over 7.4 ha (74,156 m2). This report documents the results of that effort. To understand the relative risk of losses to crab populations associated with dredging impacts at the sump alternative areas, it is recommended that a modified dredge impact model be developed using the data collected in this study. This model …
Date: January 15, 2004
Creator: Williams, Greg D.; Pearson, Walter H.; Evans, Nathan R. & Anderson, Michael G.
Object Type: Report
System: The UNT Digital Library
Biological treatment of concentrated hazardous, toxic, andradionuclide mixed wastes without dilution (open access)

Biological treatment of concentrated hazardous, toxic, andradionuclide mixed wastes without dilution

Approximately 10 percent of all radioactive wastes produced in the U. S. are mixed with hazardous or toxic chemicals and therefore can not be placed in secure land disposal facilities. Mixed wastes containing hazardous organic chemicals are often incinerated, but volatile radioactive elements are released directly into the biosphere. Some mixed wastes do not currently have any identified disposal option and are stored locally awaiting new developments. Biological treatment has been proposed as a potentially safer alternative to incineration for the treatment of hazardous organic mixed wastes, since biological treatment would not release volatile radioisotopes and the residual low-level radioactive waste would no longer be restricted from land disposal. Prior studies have shown that toxicity associated with acetonitrile is a significant limiting factor for the application of biotreatment to mixed wastes and excessive dilution was required to avoid inhibition of biological treatment. In this study, we demonstrate that a novel reactor configuration, where the concentrated toxic waste is drip-fed into a complete-mix bioreactor containing a pre-concentrated active microbial population, can be used to treat a surrogate acetonitrile mixed waste stream without excessive dilution. Using a drip-feed bioreactor, we were able to treat a 90,000 mg/L acetonitrile solution to less than …
Date: June 15, 2004
Creator: Stringfellow, William T.; Komada, Tatsuyuki & Chang, Li-Yang
Object Type: Report
System: The UNT Digital Library
Biosphere dose conversion Factor Importance and Sensitivity Analysis (open access)

Biosphere dose conversion Factor Importance and Sensitivity Analysis

This report presents importance and sensitivity analysis for the environmental radiation model for Yucca Mountain, Nevada (ERMYN). ERMYN is a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis concerns the output of the model, biosphere dose conversion factors (BDCFs) for the groundwater, and the volcanic ash exposure scenarios. It identifies important processes and parameters that influence the BDCF values and distributions, enhances understanding of the relative importance of the physical and environmental processes on the outcome of the biosphere model, includes a detailed pathway analysis for key radionuclides, and evaluates the appropriateness of selected parameter values that are not site-specific or have large uncertainty.
Date: October 15, 2004
Creator: Wasiolek, M.
Object Type: Report
System: The UNT Digital Library
Biosynthetic Approaches to Isotope Enrichment for Applications in Neutron Scattering and High Field NMR Spectroscopy: Methylotrophic (open access)

Biosynthetic Approaches to Isotope Enrichment for Applications in Neutron Scattering and High Field NMR Spectroscopy: Methylotrophic

Limitations in current isotopic labeling methods present a substantial bottleneck for the application of advanced structural techniques to many important biochemical problems. New tools are required to efficiently produce the necessary labeling patterns in biochemical precursors and incorporate them into protein molecules for structural studies. This project proposed involved one aspect of this problem, the development of expression vectors for a methylotrophic bacterium, Methylobacterium extorquens AM1. If high-level, efficient expression could be obtained in such a bacterium, it would be possible to use low-cost {sup 2}H- and/or {sup 13}C-labeled substrates such as methanol to label proteins. The Lidstrom laboratory at the University of Washington worked closely with the collaborators at Los Alamos National Laboratories in the development and use of these vectors. (1) Overexpression of a target gene, bacterial dehalogenase--This enzyme was expressed in Methylobacterium extorquens AM1 using a high level methanol-inducible promoter, the mxaF promoter. High expression was achieved, but most was in an insoluble form. They expressed this protein in a mutant lacking polybetahydroxybutyrate granules, and high expression was achieved, up to 10% of the total soluble protein. The recombinant protein was purified and shown to be active, with characteristics similar to the enzyme produced in E. coli. …
Date: September 15, 2004
Creator: lidstrom, Mary E.
Object Type: Report
System: The UNT Digital Library
Boundary Layer Cloudiness Parameterizations Using ARM Observations (open access)

Boundary Layer Cloudiness Parameterizations Using ARM Observations

This study used DOE ARM data and facilities to: (1) study macroscopic properties of continental stratus clouds at SGP and the factors controlling these properties, (2) develop a scientific basis for understanding the processes responsible for the formation of boundary layer clouds using ARM observations in conjunction with simple parametric models and LES, and (3) evaluate cumulus cloud characteristics retrieved from the MMCR operating at TWP-Nauru. In addition we have used high resolution 94 GHz observations of boundary layer clouds and precipitation to: (1) develop techniques for using high temporal resolution Doppler velocities to study large-eddy circulations and turbulence in boundary layer clouds and estimate the limitations of using current and past MMCR data for boundary layer cloud studies, (2) evaluate the capability and limitations of the current MMCR data for estimating reflectivity, vertical velocities, and spectral under low- signal-to-noise conditions associated with weak no n-precipitating clouds, (3) develop possible sampling modes for the new MMCR processors to allow for adequate sampling of boundary layer clouds, and (4) retrieve updraft and downdraft structures under precipitating conditions.
Date: September 15, 2004
Creator: Albrecht, Bruce
Object Type: Report
System: The UNT Digital Library