Analysis of Events Associated with First Charge of Desicooler Material (open access)

Analysis of Events Associated with First Charge of Desicooler Material

HB-Line's mission included dissolution of uranium-aluminum scrap left over from a U3O8 scrap recovery program begun in 1972 with material returned from Rocky Flats and Oak Ridge. This material has been stored in desicooler containers, and is commonly referred to as the Desicoolers. The Scrap Recovery process includes the dissolution of scrap material and transfer of the resulting solution to H-Canyon for further disposition. During the first charge of this material into the HB-Line dissolvers, the solution heated to boiling without external heat being added. Yellow-colored fumes, which dissipated rapidly, were noted in the glovebox by operators, and a small amount of liquid was noted in the glovebox by operations after dissolver cooldown. This technical report documents analysis of the data from the event with respect to potential Safety Basis violation and the Integrated Safety Management System process. Based on the analysis presented, the safety basis has shown its ability to protect the worker, the facility and the public.
Date: September 15, 2003
Creator: Alexander, D. E.
Object Type: Report
System: The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT (open access)

EARLY ENTRANCE COPRODUCTION PLANT

The 1999 U. S. Department of Energy (DOE) award to Texaco Energy Systems Inc. (presently Texaco Energy Systems LLC, a subsidiary of ChevronTexaco) was made to provide a Preliminary Engineering Design of an Early Entrance Coproduction Plant (EECP). Since the award presentation, work has been undertaken to achieve an economical concept design that makes strides toward the DOE Vision 21 goal. The objective of the EECP is to convert coal and/or petroleum coke to electric power plus transportation fuels, chemicals and useful utilities such as steam. The use of petroleum coke was added as a fuel to reduce the cost of feedstock and also to increase the probability of commercial implementation of the EECP concept. This objective has been pursued in a three phase effort through the partnership of the DOE with prime contractor Texaco Energy Systems LLC and subcontractors General Electric (GE), Praxair, and Kellogg Brown and Root (KBR). ChevronTexaco is providing gasification technology and Rentech's Fischer-Tropsch technology that has been developed for non-natural gas feed sources. GE is providing gas turbine technology for the combustion of low energy content gas. Praxair is providing air separation technology, and KBR is providing engineering to integrate the facility. The objective of …
Date: September 15, 2003
Creator: Benham, Charles; Bohn, Mark; Anderson, John; Berry, Earl; Brent, Fred; He, Ming et al.
Object Type: Report
System: The UNT Digital Library
The ASTRAL Compendium in 2004 (open access)

The ASTRAL Compendium in 2004

The ASTRAL compendium provides several databases and tools to aid in the analysis of protein structures, particularly through the use of their sequences. Partially derived from the SCOP database of protein structure domains, it includes sequences for each domain and other resources useful for studying these sequences and domain structures. The current release of ASTRAL contains 54,745 domains, more than three times as many as the initial release four years ago. ASTRAL has undergone major transformations in the past two years. In addition to several complete updates each year, ASTRAL is now updated on a weekly basis with preliminary classifications of domains from newly released PDB structures. These classifications are available as a stand-alone database, as well as available integrated into other ASTRAL databases such as representative subsets. To enhance the utility of ASTRAL to structural biologists, all SCOP domains are now made available as PDB-style coordinate files as well as sequences. In addition to sequences and representative subsets based on SCOP domains, sequences and subsets based on PDB chains are newly included in ASTRAL. Several search tools have been added to ASTRAL to facilitate retrieval of data by individual users and automated methods. ASTRAL may be accessed at http://astral.stanford.edu/.
Date: September 15, 2003
Creator: Chandonia, John-Marc; Hon, Gary; Walker, Nigel S.; Lo Conte, Loredana; Koehl, Patrice; Levitt, Michael et al.
Object Type: Article
System: The UNT Digital Library
Computational Science at Brookhaven National Laboratory: Three Selected Topics. (open access)

Computational Science at Brookhaven National Laboratory: Three Selected Topics.

We present an overview of computational science at Brookhaven National Laboratory (BNL), with selections from three areas: fluids, nanoscience, and biology. The work at BNL in each of these areas is itself very broad, and we select a few topics for presentation within each of them.
Date: September 15, 2003
Creator: Davenport, J. W.; Deng, Y.; Glimm, J. & Samulyak, R.
Object Type: Article
System: The UNT Digital Library
Porting the 3D Gyrokinetic Particle-in-cell Code GTC to the CRAY/NEC SX-6 Vector Architecture: Perspectives and Challenges (open access)

Porting the 3D Gyrokinetic Particle-in-cell Code GTC to the CRAY/NEC SX-6 Vector Architecture: Perspectives and Challenges

Several years of optimization on the super-scalar architecture has made it more difficult to port the current version of the 3D particle-in-cell code GTC to the CRAY/NEC SX-6 vector architecture. This paper explains the initial work that has been done to port this code to the SX-6 computer and to optimize the most time consuming parts. Early performance results are shown and compared to the same test done on the IBM SP Power 3 and Power 4 machines.
Date: September 15, 2003
Creator: Ethier, S. & Lin, Z.
Object Type: Report
System: The UNT Digital Library
Aspects of diffraction at the Tevatron (open access)

Aspects of diffraction at the Tevatron

Results on soft and hard diffraction obtained by the CDF Collaboration at the Fermilab Tevatron {bar p}p Collider are reviewed with emphasis on aspects of the data that point to the underlying QCD mechanism for diffraction. The results are interpreted in terms of a phenomenological approach in which diffraction is due to an exchange of low-x partons subject to color constraints.
Date: September 15, 2003
Creator: Goulianos, K.
Object Type: Article
System: The UNT Digital Library
LHC detector upgrades (open access)

LHC detector upgrades

The LHC detectors are well into their construction phase. The LHC schedule shows first beam to ATLAS and CMS in 2007. Because the LHC accelerator has begun to plan for a ten fold increase in LHC design luminosity (the SLHC or super LHC) it is none too soon to begin to think about the upgrades which will be required of the present LHC detectors. In particular, the tracking systems of ATLAS and CMS will need to be completely rebuilt. Given the time needed to do the R & D, make prototypes, and construct the new detectors and given the accelerator schedule for the SLHC, work needs to begin rather soon.
Date: September 15, 2003
Creator: Green, Dan
Object Type: Article
System: The UNT Digital Library
Design issues for cryogenic cooling of short periodsuperconducting undulators (open access)

Design issues for cryogenic cooling of short periodsuperconducting undulators

Superconducting insertion devices, which produce periodic magnetic fields, have been built and installed in a number of synchrotron-light source storage-rings. For the most part, these devices have been wigglers, which have relatively long period lengths. This report concerns itself with the special cryogenic issues associated with short period undulators. The motivation for considering the incorporation of superconducting technology in insertion device designs is to achieve higher magnetic fields than can be achieved with more conventional permanent magnet technology. Since the peak field decreases sharply with increased magnet gap to period ratio, the cryogenic design of the magnet system is crucial. In particular, the insulation required for a warm vacuum bore device is impractical for short period undulators. This report describes the issues that are related to a cold bore ({approx}4 K) and an intermediate temperature bore (30 to 70 K) designs. The criteria for the use of small cryocoolers for cooling a short period undulator are presented. The problems associated with connecting small coolers to an undulator at 4.2 K are discussed.
Date: September 15, 2003
Creator: Green, M. A.; Dietderich, D. R.; Marks, S.; Prestemon, S. O. & Schlueter, R. D.
Object Type: Article
System: The UNT Digital Library
A heat exchanger between forced flow helium gas at 14 to 18 K andliquid hydrogen at 20 K circulated by natural convection (open access)

A heat exchanger between forced flow helium gas at 14 to 18 K andliquid hydrogen at 20 K circulated by natural convection

The Muon Ionization Cooling Experiment (MICE) has three 350-mm long liquid hydrogen absorbers to reduce the momentum of 200 MeV muons in all directions. The muons are then re-accelerated in the longitudinal direction by 200 MHz RF cavities. The result is cooled muons with a reduced emittance. The energy from the muons is taken up by the liquid hydrogen in the absorber. The hydrogen in the MICE absorbers is cooled by natural convection to the walls of the absorber that are in turn cooled by helium gas that enters at 14 K. This report describes the MICE liquid hydrogen absorber and the heat exchanger between the liquid hydrogen and the helium gas that flows through passages in the absorber wall.
Date: September 15, 2003
Creator: Green, M. A.; Ishimoto, S.; Lau, W. & Yang, S.
Object Type: Article
System: The UNT Digital Library
Focusing solenoids for the MICE cooling channel (open access)

Focusing solenoids for the MICE cooling channel

This report describes a design for focusing solenoids for the low beta sections for the proposed Muon Ionization Cooling Experiment (MICE). There are three focusing solenoid pairs that will be around the muon absorbers for MICE. The two solenoid coils have an inside diameter of 510 mm, a length of 180 mm, and a thickness of 100 mm. A distance of 260 mm separates the two coils in the pair. The coils are designed to operate at opposite polarity, in order to create a gradient field in the low beta sections of the MICE cooling channel. As result, the force pushing the coil pair apart approaches 270 metric tons when the coils operate close to the short sample current for the superconductor. The forces between the coils will be carried by a support structure that is both on the inside and the outside the coils. During some modes of operation for MICE, the coils may operate at the same polarity, which means that the force between the coils pushes them together. The focusing magnet must be designed for both modes of operation. This support structure for the coils will be part of the focusing magnet quench protection system.
Date: September 15, 2003
Creator: Green, M.A.; Baynham, E.; Barr, G.; Lau, W.; Rochford, J.H. & Yang, S.
Object Type: Article
System: The UNT Digital Library
Developing Smart Seismic Arrays: A Simulation Environment, Observational Database, and Advanced Signal Processing (open access)

Developing Smart Seismic Arrays: A Simulation Environment, Observational Database, and Advanced Signal Processing

Seismic imaging and tracking methods have intelligence and monitoring applications. Current systems, however, do not adequately calibrate or model the unknown geological heterogeneity. Current systems are also not designed for rapid data acquisition and analysis in the field. This project seeks to build the core technological capabilities coupled with innovative deployment, processing, and analysis methodologies to allow seismic methods to be effectively utilized in the applications of seismic imaging and vehicle tracking where rapid (minutes to hours) and real-time analysis is required. The goal of this project is to build capabilities in acquisition system design, utilization and in full 3D finite difference modeling as well as statistical characterization of geological heterogeneity. Such capabilities coupled with a rapid field analysis methodology based on matched field processing are applied to problems associated with surveillance, battlefield management, finding hard and deeply buried targets, and portal monitoring. This project benefits the U.S. military and intelligence community in support of LLNL's national-security mission. FY03 was the final year of this project. In the 2.5 years this project has been active, numerous and varied developments and milestones have been accomplished. A wireless communication module for seismic data was developed to facilitate rapid seismic data acquisition and …
Date: September 15, 2003
Creator: Harben, P E; Harris, D; Myers, S; Larsen, S; Wagoner, J; Trebes, J et al.
Object Type: Report
System: The UNT Digital Library
C-200 Series Tanks Vacuum Retrieval System Aerosol Test Results (open access)

C-200 Series Tanks Vacuum Retrieval System Aerosol Test Results

The radioactive wastes stored in tanks 241-C-201, 241-C-202, 241-C-203, and 241-C-204 (the C-200 series tanks) are to be retrieved with the C-200 vacuum retrieval system (VRS). The VRS will suck the waste up through an articulated mast system, separate it from the suspending air, collect and transfer it to a receiver batch tank, and return the air as exhaust to the waste tank being retrieved. An analysis of potential accidents has indicated that a break in the line used to return the exhaust to the waste tank could release unacceptable quantities of suspended radioactive material to the environment. To estimate the quantity of suspended material and determine accident risks, CH2M HILL and Pacific Northwest National Laboratory (PNNL) conducted tests with the VRS using nonradioactive waste simulants at the Hanford Cold Test Facility. This report describes the tests conducted and presents and discusses the results.
Date: September 15, 2003
Creator: Huckaby, James L.; Glissmeyer, John A. & Gray, Paul E.
Object Type: Report
System: The UNT Digital Library
Marginal Stability Boundaries for Infinite-n Ballooning Modes in a Quasi-axisymmetric Stellarator (open access)

Marginal Stability Boundaries for Infinite-n Ballooning Modes in a Quasi-axisymmetric Stellarator

A method for computing the ideal-MHD stability boundaries in three-dimensional equilibria is employed. Following Hegna and Nakajima [Phys. Plasmas 5 (May 1998) 1336], a two-dimensional family of equilibria are constructed by perturbing the pressure and rotational-transform profiles in the vicinity of a flux surface for a given stellarator equilibrium. The perturbations are constrained to preserve the magnetohydrodynamic equilibrium condition. For each perturbed equilibrium, the infinite-n ballooning stability is calculated. Marginal stability diagrams are thus constructed that are analogous to (s; a) diagrams for axisymmetric configurations. A quasi-axisymmetric stellarator is considered. Calculations of stability boundaries generally show regions of instability can occur for either sign of the average magnetic shear. Additionally, regions of second-stability are present.
Date: September 15, 2003
Creator: Hudson, S. R. & Hegna, C. C.
Object Type: Report
System: The UNT Digital Library
Constructing Integrable High-pressure Full-current Free-boundary Stellarator Magnetohydrodynamic Equilibrium Solutions (open access)

Constructing Integrable High-pressure Full-current Free-boundary Stellarator Magnetohydrodynamic Equilibrium Solutions

For the (non-axisymmetric) stellarator class of plasma confinement devices to be feasible candidates for fusion power stations it is essential that, to a good approximation, the magnetic field lines lie on nested flux surfaces; however, the inherent lack of a continuous symmetry implies that magnetic islands responsible for breaking the smooth topology of the flux surfaces are guaranteed to exist. Thus, the suppression of magnetic islands is a critical issue for stellarator design, particularly for small aspect ratio devices. Pfirsch-Schluter currents, diamagnetic currents, and resonant coil fields contribute to the formation of magnetic islands, and the challenge is to design the plasma and coils such that these effects cancel. Magnetic islands in free-boundary high-pressure full-current stellarator magnetohydrodynamic equilibria are suppressed using a procedure based on the Princeton Iterative Equilibrium Solver [Reiman and Greenside, Comp. Phys. Comm. 43 (1986) 157] which iterate s the equilibrium equations to obtain the plasma equilibrium. At each iteration, changes to a Fourier representation of the coil geometry are made to cancel resonant fields produced by the plasma. The changes are constrained to preserve certain measures of engineering acceptability and to preserve the stability of ideal kink modes. As the iterations continue, the coil geometry and …
Date: September 15, 2003
Creator: Hudson, S. R.; Monticello, D. A.; Reiman, A. H.; Strickler, D. J.; Hirshman, S. P.; Ku, L. P. et al.
Object Type: Report
System: The UNT Digital Library
PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP: THEORY STUDIES FOR POLARIZED PP SCATTERING (VOLUME 53) (open access)

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP: THEORY STUDIES FOR POLARIZED PP SCATTERING (VOLUME 53)

In the past two runs of RHIC, the first measurements with polarized proton beams have been performed. For many years to come, the RHIC spin program will offer exciting physics, exploring QCD and the nucleon in new ways. The aim of this small workshop was to attract several spin theorists to the center for about two weeks, in order to collaborate with both experimentalists and theorists at RBRC, and to initiate and/or complete studies of relevance to RHIC spin. A major focus of polarized-pp measurements at RHIC is on measuring the spin-dependent gluon density, {Delta}g. A channel for accessing {Delta}g is high-p{sub T} pion production. The unpolarized cross section for this reaction has been measured by PHENIX and was found in good agreement with a perturbative-QCD based (NLO) calculation. It was a remarkable and exciting coincidence that PHENIX presented also the first results for the spin asymmetry for {rvec p}{rvec p} {yields} {pi}{sup 0}X during this workshop. This sparked a lot of additional activity and discussion. First steps toward the interpretation of the data were taken. Marco Stratmann and Barbara Jager (Regensburg University) presented recent work on the NLO calculation of the polarized cross section and the spin asymmetry, setting …
Date: September 15, 2003
Creator: KRETZER,S. VOGELSANG,W.
Object Type: Report
System: The UNT Digital Library
Grid-based Parallel Data Streaming Implemented for the Gyrokinetic Toroidal Code (open access)

Grid-based Parallel Data Streaming Implemented for the Gyrokinetic Toroidal Code

We have developed a threaded parallel data streaming approach using Globus to transfer multi-terabyte simulation data from a remote supercomputer to the scientist's home analysis/visualization cluster, as the simulation executes, with negligible overhead. Data transfer experiments show that this concurrent data transfer approach is more favorable compared with writing to local disk and then transferring this data to be post-processed. The present approach is conducive to using the grid to pipeline the simulation with post-processing and visualization. We have applied this method to the Gyrokinetic Toroidal Code (GTC), a 3-dimensional particle-in-cell code used to study microturbulence in magnetic confinement fusion from first principles plasma theory.
Date: September 15, 2003
Creator: Klasky, S.; Ethier, S.; Lin, Z.; Martins, K.; McCune, D. & Samtaney, R.
Object Type: Report
System: The UNT Digital Library
Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the Nine R/V Korr Cruises Comprising the Indian Ocean CO<sub>2</sub>Survey (WOCE Sections I8SI9S, I9N, I8NI5E, I3, I5WI4, I7N, I1, I10, and I2; December 1, 1994-January 19, 1996) (open access)

Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the Nine R/V Korr Cruises Comprising the Indian Ocean CO<sub>2</sub>Survey (WOCE Sections I8SI9S, I9N, I8NI5E, I3, I5WI4, I7N, I1, I10, and I2; December 1, 1994-January 19, 1996)

This document describes the procedures and methods used to measure total carbon dioxide (TCO{sub 2}) and total alkalinity (TALK) at hydrographic stations taken during the R/V Knorr Indian Ocean cruises (Sections I8SI9S, I9N, I8NI5E, I3, I5WI4, I7N, I1, I10, and I2) in 1994-1996. The measurements were conducted as part of the World Ocean Circulation Experiment (WOCE). The expedition began in Fremantle, Australia, on December 1, 1994, and ended in Mombasa, Kenya, on January 22, 1996. During the nine cruises, 12 WOCE sections were occupied. Total carbon dioxide was extracted from water samples and measured using single-operator multiparameter metabolic analyzers (SOMMAs) coupled to coulometers. The overall precision and accuracy of the analyses was {+-} 1.20 {micro}mol/kg. The second carbonate system parameter, TALK, was determined by potentiometric titration. The precision of the measurements determined from 962 analyses of certified reference material was {+-} 4.2 {micro}mol/kg (REFERENCE). This work was supported by grants from the National Science Foundation, the U. S. Department of Energy, and the National Oceanographic and Atmospheric Administration. The R/V Knorr Indian Ocean data set is available as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center (CDIAC). The NDP consists of 18 oceanographic data files, two …
Date: September 15, 2003
Creator: Kozyr, A.V.
Object Type: Report
System: The UNT Digital Library
DPAL: A New Class of Lasers for CW Power Beaming at Ideal Photovoltaic Cell Wavelengths (open access)

DPAL: A New Class of Lasers for CW Power Beaming at Ideal Photovoltaic Cell Wavelengths

The new class of diode pumped alkali vapor lasers (DPALs) offers high efficiency cw laser beams at wavelengths which efficiently couple to photovoltaic (PV) cells: silicon cells at 895 nm (cesium), and GaAs cells at 795 nm (rubidium) and at 770 nm (potassium). DPAL electrical efficiencies of 25-30% are projected, enabling PV cell efficiencies {approx}40% (Si) and {approx}60% (GaAs). Near-diffraction-limited DPAL device power scaling into the multi-kilowatt regime from a single aperture is projected.
Date: September 15, 2003
Creator: Krupke, W F; Beach, R J; Payne, S A; Kanz, V K & Early, J T
Object Type: Article
System: The UNT Digital Library
Regulation of the transcriptional activator NtrC1: Structural studies of the regulatory and AAA{sup +} ATPase domains (open access)

Regulation of the transcriptional activator NtrC1: Structural studies of the regulatory and AAA{sup +} ATPase domains

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Date: September 15, 2003
Creator: Lee, Seok-Yong; De La Torre, Armando; Yan, Dalai; Kustu, Sydney; Nixon, Tracy B. & Wemmer, David E.
Object Type: Article
System: The UNT Digital Library
Supporting integrated design through interlinked tools: The Labs21 toolkit (open access)

Supporting integrated design through interlinked tools: The Labs21 toolkit

The sustainable design of complex building types such as laboratories and hospitals can be particularly challenging, given their inherent complexity of systems, health and safety requirements, long-term flexibility and adaptability needs, energy use intensity, and environmental impacts. Tools such as design guides, energy benchmarking, and LEED rating systems are especially helpful to support sustainable design in such buildings. Furthermore, designers need guidance on how to effectively and appropriately use each tool within the context of an integrated design process involving multiple actors with various objectives. Toward this end, the Laboratories for the 21st Century (Labs21) program has developed an interlinked set of tools -- the Labs21 Toolkit -- to support an integrated design process for sustainable laboratories. Labs21 is a voluntary partnership program sponsored by the U.S. Environmental Protection Agency (EPA) and U.S. Department of Energy (DOE) to improve the environment al performance of U.S. laboratories. In this paper, we present the Labs21 Toolkit, and illustrate how these tools can be used to support sustainable design within an integrated design process. The tool kit includes core information tools, as well as process-related tools, as indicated below: Core information tools: -A Design Guide, which is a compendium of publications on energy …
Date: September 15, 2003
Creator: Mathew, Paul; Bell, Geoffrey; Carlisle, Nancy; Sartor, Dale; van Geet, Otto; Lintner, William et al.
Object Type: Article
System: The UNT Digital Library
Brighter Screens for Nondestructive Digital X-ray Radiography (open access)

Brighter Screens for Nondestructive Digital X-ray Radiography

Fine resolution, bright X-ray screens are needed for digital radiography and material characterization at the Y-12 National Security Complex (Y-12). Current technology is simply not adequate for transferring high-energy X-ray images to visible light for demanding digital applications. Low energy radiography and especially emerging tomographic technologies are severely hampered for Y-12 nondestructive evaluation (NDE) applications by dim screens with poor resolution. Also, the development of more advanced materials characterization techniques, such as electron backscatter diffraction (EBSD), is driven by a design agency desire for tighter specifications and more uniform materials. Brighter screens would allow us to probe materials on a finer scale, leading to a better understanding of material behavior. A number of X-ray screen materials were studied that would be suitable for direct replacement in existing digital imaging systems. Spectroscopic evaluations were first made for a several candidates and indicated that lutetium orthosilicate (LSO) would be a promising candidate for MeV images. A relative comparison of brightness at various energies was then completed which showed that cesium iodide (CsI) could increase brightness by over an order of magnitude. Since image quality is also important for better screens, the resolving capabilities of candidate materials were measured. Resolution measurements were completed …
Date: September 15, 2003
Creator: Miller, A. C., Jr.; Bell, Z. W. & Carpenter, D. A.
Object Type: Report
System: The UNT Digital Library
The National Ignition Facility High-Energy Ultraviolet Laser System (open access)

The National Ignition Facility High-Energy Ultraviolet Laser System

The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1 .&amp;Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the world's largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF's 192 energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will allow the study of physical processes at temperatures approaching 10{sup 8} K and 10{sup 11} Bar, conditions that exist naturally only in the interior of stars, planets and in nuclear weapons. NIF is now entering the first phases of its laser commissioning program. The first four beams of the NIF laser system have generated 106 kilojoules of infrared light and over 10 kJ at the third harmonic (351 nm). NIF's target experimental systems are also being installed in preparation for experiments to begin in late 2003. This paper provides a detailed look the NIF laser systems, …
Date: September 15, 2003
Creator: Moses, E I
Object Type: Article
System: The UNT Digital Library
Interannual Variability in Global Soil Respiration on a 0.5 Degree Grid Cell Basis (1980-1994) (open access)

Interannual Variability in Global Soil Respiration on a 0.5 Degree Grid Cell Basis (1980-1994)

We used a climate-driven regression model to develop spatially resolved estimates of soil-CO{sub 2} emissions from the terrestrial land surface for each month from January 1980 to December 1994, to evaluate the effects of interannual variations in climate on global soil-to-atmosphere CO{sub 2} fluxes. The mean annual global soil-CO{sub 2} flux over this 15-y period was estimated to be 80.4 (range 79.3-81.8) Pg C. Monthly variations in global soil-CO{sub 2} emissions followed closely the mean temperature cycle of the Northern Hemisphere. Globally, soil-CO{sub 2} emissions reached their minima in February and peaked in July and August. Tropical and subtropical evergreen broad-leaved forests contributed more soil-derived CO{sub 2} to the atmosphere than did any other vegetation type ({approx}30% of the total) and exhibited a biannual cycle in their emissions. Soil-CO{sub 2} emissions in other biomes exhibited a single annual cycle that paralleled the seasonal temperature cycle. Interannual variability in estimated global soil-CO{sub 2} production is substantially less than is variability in net carbon uptake by plants (i.e., net primary productivity). Thus, soils appear to buffer atmospheric CO{sub 2} concentrations against far more dramatic seasonal and interannual differences in plant growth. Within seasonally dry biomes (savannas, bushlands, and deserts), interannual variability in …
Date: September 15, 2003
Creator: Raich, J.W.
Object Type: Report
System: The UNT Digital Library
The Innovations, Technology and Waste Management Approaches to Safely Package and Transport the World's First Radioactive Fusion Research Reactor for Burial (open access)

The Innovations, Technology and Waste Management Approaches to Safely Package and Transport the World's First Radioactive Fusion Research Reactor for Burial

Original estimates stated that the amount of radioactive waste that will be generated during the dismantling of the Tokamak Fusion Test Reactor will approach two million kilograms with an associated volume of 2,500 cubic meters. The materials were activated by 14 MeV neutrons and were highly contaminated with tritium, which present unique challenges to maintain integrity during packaging and transportation. In addition, the majority of this material is stainless steel and copper structural metal that were specifically designed and manufactured for this one-of-a-kind fusion research reactor. This provided further complexity in planning and managing the waste. We will discuss the engineering concepts, innovative practices, and technologies that were utilized to size reduce, stabilize, and package the many unique and complex components of this reactor. This waste was packaged and shipped in many different configurations and methods according to the transportation regulations and disposal facility requirements. For this particular project, we were able to utilize two separate disposal facilities for burial. This paper will conclude with a complete summary of the actual results of the waste management costs, volumes, and best practices that were developed from this groundbreaking and successful project.
Date: September 15, 2003
Creator: Rule, Keith; Perry, Erik; Chrzanowski, Jim; Viola, Mike & Strykowsky, Ron
Object Type: Report
System: The UNT Digital Library