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Heat transfer augmentation in channels with porous copper inserts.
None
Date:
May 19, 1998
Creator:
Kuzay, T. M.
Object Type:
Article
System:
The UNT Digital Library
On the Use of Reanalysis Data for Wind Resource Assessment
The goal of the U.S. Department of Energy (DOE) Wind Energy Program's wind resource assessment group located at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, is to improve the characterization of the wind resource in many regions of the world in support of the U.S. wind energy industry. NREL characterizes the level of the available wind resource at wind turbine hub heights (typically 30 m to 50 m above ground level) using wind power density, expressed in units of Watts per square meter. Wind power density values are frequently used to classify the wind resource level with the higher wind power classes assigned to areas with high power density values. NREL has developed a wind assessment methodology to produce wind resource maps useful for wind prospecting and wind energy project implementation. The methodology integrates information from global climatic data sets and also involves a critical meteorologic analysis of the climatic data. It is in the context of the critical meteorological analysis and the automated mapping system that we plan to evaluate the usefulness of Reanalysis data for wind assessment purposes.
Date:
November 19, 1998
Creator:
Schwartz, M. N. & George, R. L.
Object Type:
Article
System:
The UNT Digital Library
Evolution of 2D Potts Model Grain Microstructures from an Initial Hillert Size Distribution
Grain growth experiments and simulations exhibit self-similar grain size distributions quite different from that derived via a mean field approach by Hillert [ 1]. To test whether this discrepancy is due to insufficient anneal times, two different two-dimensional grain structures with realistic topologies and Hillert grain size distributions are generated and subjected to grain growth via the Monte Carlo Potts Model (MCPM). In both cases, the observed self-similar grain size distributions deviate from the initial Hillert form and conform instead to that observed in MCPM grain growth simulations that start from a random microstructure. This suggests that the Hillert grain size distribution is not an attractor.
Date:
October 19, 1998
Creator:
Battaile, C.C. & E.A., Holm
Object Type:
Article
System:
The UNT Digital Library
Design of high density gamma-phase uranium alloys for LEU dispersion fuel applications.
Uranium alloys are candidates for the fuel phase in aluminum matrix dispersion fuels requiring high uranium loading. Certain uranium alloys have been shown to have good irradiation performance at intermediate burnup. Previous studies have shown that acceptable fission gas swelling behavior and fuel-aluminum interaction is possible only if the fuel alloy can be maintained in the high temperature body-centered-cubic {gamma}-phase during fabrication and irradiation, i.e., at temperatures at which {alpha}-U is the equilibrium phase. Transition metals in Groups V through VIII are known to allow metastable retention of the gamma phase below the equilibrium isotherm. These metals have varying degrees of effectiveness in stabilizing the gamma phase. Certain alloys are metastable for very long times at the relatively low fuel temperatures seen in research reactor operation. In this paper, the existing data on the gamma stability of binary and ternary uranium alloys is analyzed. The mechanism and kinetics of decomposition of the gamma phase are assessed with the help of metal alloy theory. Alloys with the highest possible uranium content, good gamma-phase stability, and good neutronic performance are identified for further metallurgical studies and irradiation tests. Results from theory will be compared with experimentally generated data.
Date:
October 19, 1998
Creator:
Hofman, G. L.
Object Type:
Article
System:
The UNT Digital Library
Estimation of upper bound probabilities for rare events resulting from nearby explosions
It is sometimes necessary to deploy, transport and store weapons containing high explosives (HE) in proximity. Accident analyses of these activities may include nearby explosion scenarios in which fragments from an exploding (donor) weapon impact a second (acceptor) weapon. Weapon arrays are designed to miti- gate consequences to potential acceptor weapons, but unless initiation of an accep- tor's HE is impossible, outcomes such as detonation must be considered. This paper describes an approach for estimating upper bound probabilities for fragment- dominated scenarios in which outcomes are expected to be rare events. Other aspectsl,z of nearby explosion problems were addressed previously. An example scenario is as follows. A donor weapon is postulated to detonate, and fragments of the donor weapon casing are accelerated outward. Some of the fragments may strike a nearby acceptor weapon whose HE is protected by casing materials. Most impacts are not capable of initiating the acceptor's HE. However, a sufficiently large and fast fragment could produce a shock-to-detonation transi- tion (SDT), which will result in detonation of the acceptor. Our approach will work for other outcomes of fragment impact, but this discussion focuses on detonation. Experiments show that detonating weapons typically produce a distribution of casing fragment …
Date:
September 19, 1998
Creator:
Luck, L.B.
Object Type:
Article
System:
The UNT Digital Library
The RERTR Program : a status report.
This paper describes the progress achieved by the Reduced Enrichment for Research and Test Reactors (RERTR) Program in collaboration with its many international partners since its inception in 1978. A brief summary of the results that the program had attained by the end of 1997 is followed by a detailed review of the major events, findings, and activities that took place in 1998. The past year was characterized by exceptionally important accomplishments and events for the RERTR program. Four additional shipments of spent fuel from foreign research reactors were accepted by the U.S. Altogether, 2,231 spent fuel assemblies from foreign research reactors have been received by the U.S. under the acceptance policy. Fuel development activities began to yield solid results. Irradiations of the first two batches of microplates were completed. Preliminary postirradiation examinations of these microplates indicate excellent irradiation behavior of some of the fuel materials that were tested. These materials hold the promise of achieving the pro am goal of developing LEU research reactor fuels with uranium density in the 8-9 g /cm{sup 3} range. Progress was made in the Russian RERTR program, which aims to develop and demonstrate the technical means needed to convert Russian-supplied research reactors to …
Date:
October 19, 1998
Creator:
Travelli, A.
Object Type:
Article
System:
The UNT Digital Library
Development of practical damage-mapping and inspection systems
We have developed and are continuing to refine semi-automated technology for the detection and inspection of surface and bulk defects and damage in large laser optics Different manifestations of the DAMOCLES system (Damage and Artifact Mapping Of Coherent-Laser-Exposed Substrates) provide an effective and economical means of being able to detect, map and characterize surface and bulk defects which may become precursors of massive damage in optics when subjected to high-fluence laser irradiation Subsequent morphology and evolution of damage due to laser irradiation can be tracked efficiently The strength of the Damocles system is that it allows for immediate visual observation of defects in an entire optic, which can range up to l-meter dimensions, while also being able to provide digital map and magnified images of the defects with resolutions better than 5 µm.
Date:
August 19, 1998
Creator:
Rainer, F.
Object Type:
Article
System:
The UNT Digital Library
Conformational Diversity in (Octaethylporphinato) (trichloroacetato)iron(III) Derivatives
Treatment of [Fe(OEP)]20 with trichloroacetic acid results in ruffled formation of (octaethylporphinato trichloroacetato)iron(HI). Various crystalline solvates can be isolated, depending on the crystallization solvent. Initial crystallization with CHC13/hexanes resulted in the isolation of an unsolvated form. [Fe(OEP)(02C2C13 )]. This form contains distinct porphyrin core conformations at the same site: one is domed and the other is ruffled. Crystal data for [Fe(OEP)(02C2C13 )]: Q = 14.734(4) .4. b = 13.674(1) .\. c = 17..541 [,.5] .~. 3 = 90.67(1)0, V = 35-!5.8(14) .\3. monoclinic. space group R1/ n. Z = 4. Subsequent crystallization with CHC13/hexanes resulted in a new crystalline form, [Fe(OEP)(OzC2C13 )~.- CHC13; the porphyrin core is slightly ruffled. Crystal data for [Fe(OEP)(OoC2C13 )]. CHC13: a =12.323(1) .~, 6 = 13.062(3) .\. C = 14.327(2) .$, Q = 89.32(1)", .3 = 113.36(2)0. :~ = 105.26(1)'. V = `2031.3(6) .\3. triclinic. space group Pi. Z = 2. Crystallization with CH2C12/hexanes resulted in the isolation of yet another form, [Fe(OEP) (02 C2C13)]. H02C2C13. which contains two independent molecules in the unit cell: molecule is slightly saddled and molecule B is modestly ruffled. Crystal data for [Fe(OEP)(02ClC13 )]. H02C2C13: a = 13.148(3) .\, b = 13.45.5(3) A, c = Q3.761(5) -& ~ = …
Date:
October 19, 1998
Creator:
Cheng, B.; Ma, J.; Neal, T.J.; Scheidt, W.R.; Schulz, C.E. & Shelnutt, J.A.
Object Type:
Article
System:
The UNT Digital Library
Calibration of an Advanced Photon Source linac beam position monitor used for positron position measurement of a beam containing both positrons and electrons.
The Advanced Photon Source (APS) linac beam position monitors can be used to monitor the position of a positron beam also containing electrons. To accomplish this task, both the signal at the bunching frequency of 2856 MHz and the signal at 2 x 2856 MHz are acquired and processed for each stripline. The positron beam position is obtained by forming a linear combination of both 2856- and 5712-MHz signals for each stripline and then performing the standard difference over sum computation. The required linear combination of the 2856- and 5712-MHz signals depends on the electrical calibration of each stripline/cable combination. In this paper, the calibration constants for both 2856-MHz and 5712-MHz signals for each stripline are determined using a pure beam of electrons. The calibration constants are obtained by measuring the 2856- and 5712-MHz stripline signals at various electron beam currents and positions. Finally, the calibration constants measured using electrons are used to determine positron beam position for the mixed beam case.
Date:
May 19, 1998
Creator:
Sereno, N. S.
Object Type:
Article
System:
The UNT Digital Library
Tank 241-TX-118, core 236 analytical results for the final report
This document is the analytical laboratory report for tank 241-TX-118 push mode core segments collected between April 1, 1998 and April 13, 1998. The segments were subsampled and analyzed in accordance with the Tank 241-TX-118 Push Mode Core sampling and Analysis Plan (TSAP) (Benar, 1997), the Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995), the Data Quality Objective to Support Resolution of the Organic Complexant Safety Issue (Organic DQO) (Turner, et al, 1995) and the Historical Model Evaluation Data Requirements (Historical DQO) (Sipson, et al., 1995). The analytical results are included in the data summary table (Table 1). None of the samples submitted for Differential Scanning Calorimetry (DSC) and Total Organic Carbon (TOC) exceeded notification limits as stated in the TSAP (Benar, 1997). One sample exceeded the Total Alpha Activity (AT) analysis notification limit of 38.4{micro}Ci/g (based on a bulk density of 1.6), core 236 segment 1 lower half solids (S98T001524). Appropriate notifications were made. Plutonium 239/240 analysis was requested as a secondary analysis. The statistical results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group in accordance with the Memorandum of Understanding (Schreiber, 1997) and are …
Date:
November 19, 1998
Creator:
Esch, Ruth A.
Object Type:
Report
System:
The UNT Digital Library
Combining Noise Factors and Process Parameters in a Response Surface
This presentation covers the strategy and analysis of an experiment to characterize a gas tungsten arc welding process. The experiment combined four uncontrolled noise factors and four controlled process parameters. A nontraditional response surface design was employed. Multiple responses were modeled. Optimal settings for the process parameters to successfully weld the widest range of the pertinent product features were identified. Thus, the process was made ''robust'' against ''noise'' factors. Comparisons are made between the experimental and analytical approach taken versus the Taguchi style of experimentation and analysis. This comparison is mainly done with respect to the information gained, such as product design criteria, incoming material specifications, and process adjustments for nonconforming material.
Date:
March 19, 1998
Creator:
Wyckoff, James
Object Type:
Article
System:
The UNT Digital Library
Code Development for Control Design Applications: Phase I: Structural Modeling
The design of integrated controls for a complex system like a wind turbine relies on a system model in an explicit format, e.g., state-space format. Current wind turbine codes focus on turbine simulation and not on system characterization, which is desired for controls design as well as applications like operating turbine model analysis, optimal design, and aeroelastic stability analysis. This paper reviews structural modeling that comprises three major steps: formation of component equations, assembly into system equations, and linearization.
Date:
November 19, 1998
Creator:
Bir, G. S. & Robinson, M.
Object Type:
Article
System:
The UNT Digital Library
Fluorinated Dodecaphenylporphyrins: Synthetic and Electrochemical Studies Including the First Evidence of Intramolecular Electron Transfer Between an Fe(II) Porphyrin -Anion Radical and an Fe(I) Porphyrin
Dodecaphenylporphyrins with varying degrees of fluorination of the peripheral phenyl rings (FXDPPS) were synthesized as model compounds for studying electronic effects in nonplan~ porphyrins, and detailed electrochemical studies of the chloroiron(HI) complexes of these compounds were undertaken. The series of porphyrins, represented as FeDPPCl and as FeFXDPPCl where x = 4, 8 (two isomers), 12, 20,28 or 36, could be reversibly oxidized by two electrons in dichloromethane to give n-cation radicals and n-dications. All of the compounds investigated could also be reduced by three electrons in benzonitrile or pyridine. In benzonitrile, three reversible reductions were observed for the unfluorinated compound FeDPPC1, whereas the FeFXDPPCl complexes generally exhibited irreversible first and second reductions which were coupled to chemical reactions. The chemical reaction associated with the first reduction involved a loss of the chloride ion after generation of Fe FXDPPC1. The second chemical reaction involved a novel intramolecular electron transfer between the initially generated Fe(H) porphyrin n-anion radical and the final Fe(I) porphyrin reduction product. In pyridine, three reversible one electron reductions were observed with the second reduction affording stable Fe(II) porphyrin o - anion radicals for ail of the complexes investigated.
Date:
October 19, 1998
Creator:
D'Souza, Francis; Forsyth, Timothy P.; Fukuzumi, Shunichi; Kadish, Karl M.; Krattinger, Benedicte; Lin, Min et al.
Object Type:
Article
System:
The UNT Digital Library
Preprocessing of backprojection images in the McClellan Nuclear Radiation Center tomography system
Neutron tomography is being investigated as a nondestructive technique for quantitative assessment of low atomic mass impurity concentration in metals. Neutrons maximize the sensitivity given their higher cross sections for low Z isotopes while tomography provides the three dimensional density information. The specific application is the detection of Hydrogen down to 200 ppm weight in aircraft engine compressor blades. A number of preprocessing corrections have been implemented for the backprojection images in order to achieve the detection requirements for a testing rate of three blades per hour. Among the procedures are corrections for neutron scattering and beam hardening. With these procedures the artifacts in tomographic reconstructions are shown to be less than the signal for 100 ppm hydrogen in titanium alloy samples.
Date:
February 19, 1998
Creator:
Gibbons, M. R., LLNL
Object Type:
Report
System:
The UNT Digital Library
Request for modification of 200 Area effluent treatment facility final delisting
A Delisting Petition submitted to the U.S. Environmental Protection Agency in August 1993 addressed effluent to be generated at the 200 Area Effluent Treatment Facility from treating Hanford Facility waste streams. This Delisting Petition requested that 71.9 million liters per year of treated effluent, bearing the designation 'F001' through 'F005', and/or 'F039' that is derived from 'F001' through 'F005' waste, be delisted. On June 13, 1995, the U.S. Environmental Protection Agency published the final rule (Final Delisting), which formally excluded 71.9 million liters per year of 200 Area Effluent Treatment Facility effluent from ''being listed as hazardous wastes'' (60 FR 31115 now promulgated in 40 CFR 261). Given the limited scope, it is necessary to request a modification of the Final Delisting to address the management of a more diverse multi-source leachate (F039) at the 200 Area Effluent Treatment Facility. From past operations and current cleanup activities on the Hanford Facility, a considerable amount of both liquid and solid Resource Conservation and Recovery Act of 1976 regulated mixed waste has been and continues to be generated. Ultimately this waste will be treated as necessary to meet the Resource Conservation and Recovery Act Land Disposal Restrictions. The disposal of this waste …
Date:
November 19, 1998
Creator:
BOWMAN, R.C.
Object Type:
Report
System:
The UNT Digital Library
Validation of a Model for a Two-Bladed Flexible Rotor System: Progress to Date
At the National Renewable Energy Laboratory, we tested a very flexible wind turbine. This machine, the Cannon Wind Eagle turbine, exhibited an ability to significantly reduce the rotor flap-wise bending moments through a unique combination of a flexible rotor and hub design. In parallel to this testing effort, we developed analytical models of this machine using our simulation codes. The goal of this work was to validate the analytical models of this machine by comparing analytical predictions to measured results from the real machine. We first describe briefly the simulation codes used in this study. We then describe the wind turbine we analyzed. We then describe analytical model validation progress for this flexible rotor and show preliminary validation results. Finally, we make conclusions and state our plans for future studies.
Date:
November 19, 1998
Creator:
Wright, A. D.; Kelley, N. D. & Osgood, R. M.
Object Type:
Article
System:
The UNT Digital Library
Development of nondestructive evaluation methods for structural ceramics.
During the past year, the focus of our work on nondestructive evaluation (NDE) methods was on the development and application of these methods to technologies such as ceramic matrix composite (CMC) hot-gas filters, CMC high-temperature heat exchangers, and CMC ceramic/ceramic joining. Such technologies are critical to the ''Vision 21 Energy-Plex Fleet'' of modular, high-efficiency, low-emission power systems. Specifically, our NDE work has continued toward faster, higher sensitivity, volumetric X-ray computed tomographic imaging with new amorphous silicon detectors to detect and measure axial and radial density variations in hot-gas filters and heat exchangers; explored the potential use of high-speed focal-plane-array infrared imaging technology to detect delaminations and variations in the thermal properties of SiC/SiC heat exchangers; and explored various NDE methods to characterize CMC joints in cooperation with various industrial partners. Work this year also addressed support of Southern Companies Services Inc., Power Systems Development Facility, where NDE is needed to assess the condition of hot-gas candle filters. This paper presents the results of these efforts.
Date:
August 19, 1998
Creator:
Ellingson, W. A.
Object Type:
Article
System:
The UNT Digital Library
ISIS; An Information-efficient Spectral Imaging System
A specialized hyperspectral imager has been developed that preprocesses the spectra from an image before the light reaches the detectors. This "optical computer" does not allow the flexibility of digital post-processing. However, the processing is done in real time and the system can examine = 2 x 10{sup 6} scene pixels/sec. Therefore, outdoors it could search for pollutants, vegetation types, minerals, or man-made objects. On a high- speed production line it could identify defects in sheet products like plastic wrap or film, or on painted or plastic parts. ISIS is a line scan imager. A spectrally dispersed slit image is projected on a Spatial Light Modulator. The SLM is programmed to take the inner product of the spectral intensity vector and a spectral basis vector. The SLM directs the positive and negative parts of the inner product to different linear detector arrays so the signal difference equals the inner product. We envision a system with one telescope and =4 SLMS.
Date:
July 19, 1998
Creator:
Boye, C. A.; Descour, M. R.; Gentry, S. M.; Grotbeck, C. L.; Stallard, B. R. & Sweatt, W. C.
Object Type:
Article
System:
The UNT Digital Library
Thin Film Photovoltaics
The motivation to develop thin film technologies dates back to the inception of photovoltaics. It is an idea based on achieving truly low-cost photovoltaics appropriate for mass production and energy significant markets. The key to the idea is the use of pennies worth of active materials. Since sunlight carries relatively little energy in comparison with combustion-based energy sources, photovoltaic (PV) modules must be cheap to produce energy that can be competitive. Thin films are presumed to be the answer to that low-cost requirement. But how cheap do they have to be? The following is an oversimplified analysis that allows some insight into this question.
Date:
November 19, 1998
Creator:
Zweibel, K.
Object Type:
Article
System:
The UNT Digital Library
A neutronic feasibility study for LEU conversion of the WWR-SM research reactor in Uzbekistan.
The WWR-SM research reactor in Uzbekistan has operated at 10 MW since 1979, using Russian-supplied IRT-3M fuel assemblies containing 90% enriched uranium. Burnup tests of three full-sized IRT-3M FA with 36% enrichment were successfully completed to a burn up of about {approximately}50% in 1987-1989. In August 1998, four IRT-3M FA with 36% enriched uranium were loaded into the core to initiate conversion of the entire core to 36% enriched fuel. This paper presents the results of equilibrium fuel cycle comparisons of the reactor using HEU (90%) and HEU (36%) IRT-3M fuel and compares results with the performance of IRT-4M FA containing LEU (19.75%). The results show that an LEU (19.75%) density of 3.8 g/cm{sup 3} is required to match the cycle length of the HEU (90%) core and an LEU density 3.9 g/cm{sup 3} is needed to match the cycle length of the HEU (36%) core.
Date:
October 19, 1998
Creator:
Rakhmanov, A.
Object Type:
Article
System:
The UNT Digital Library
Summary of Tritium Tracking and Groundwater Monitoring at the Hanford Site 200 Area SALDS - FY 1998
Treated water from the 200 Area Effluent Treatment Facility (ETF) is discharged to a disposal site in accordance with the State Waste Discharge Permit ST-4500. This disposal site is referred to as the State-Approved Land Disposal Site (SALDS). In accordance with the discharge permit, the groundwater at the SALDS is routinely sampled. The results of the groundwater sampling are reported in quarterly discharge monitoring reports. In 1997, the USDOE also committed to the issuance of an annual summary report of groundwater monitoring results and evaluation with updates to the groundwater monitoring plan as appropriate. This report summarizes the groundwater information for FY 1998.
Date:
October 19, 1998
Creator:
DB Barnett, MP Bergeron, CR Cole, MD Freshley, SK Wurstner
Object Type:
Report
System:
The UNT Digital Library
Evaluation of 241-AZ tank farm supporting phase 1 privatization waste feed delivery
This evaluation is one in a series of evaluations determining the process needs and assessing the adequacy of existing and planned equipment in meeting those needs at various double-shell tank farms in support of Phase 1 privatization. A number of tank-to-tank transfers and waste preparation activities are needed to process and feed waste to the private contractor in support of Phase 1 privatization. The scope of this evaluation is limited to process needs associated with 241-AZ tank farm during the Phase 1 privatization.
Date:
November 19, 1998
Creator:
Carlson, A. B.
Object Type:
Report
System:
The UNT Digital Library
Solution exchange corrosion testing with the glass-zeolite ceramic waste form in demineralized water at 90{degree}C.
A ceramic waste form of glass-bonded zeolite is being developed for the long-term disposition of fission products and transuranic elements in wastes from the U.S. Department of Energy's spent nuclear fuel conditioning activities. Solution exchange corrosion tests were performed on the ceramic waste form and its potential base constituents of glass, zeolite 5A, and sodalite as part of an effort to qualify the ceramic waste form for acceptance into the Civilian Radioactive Waste Management System. Solution exchange tests were performed at 90 C by replacing 80 to 90% of the leachate with fresh demineralized water after set time intervals. The results from these tests provide information about corrosion mechanisms and the ability of the ceramic waste form and its constituent materials to retain waste components. The results from solution exchange tests indicate that radionuclides will be preferentially retained in the zeolites without the glass matrix and in the ceramic waste form, with respect to cations like Li, K, and Na. Release results have been compared for simulated waste from candidate ceramic waste forms with zeolite 5A and its constituent materials to determine the corrosion behavior of each component.
Date:
May 19, 1998
Creator:
Simpson, L. J.
Object Type:
Article
System:
The UNT Digital Library
Self-Organized Growth of Alloy Superlattices
We predict theoretically and demonstrate experimentally the spontaneous formation of a superlattice during crystal growth. When a strained alloy grows by "step flow", the steps at the surface form periodic bunches. The resulting modulated strain biases the incorporation of the respective alloy components at different steps in the bunch, leading to the formation of a superlattice. X-ray diffraction and electron microscopy for SiGe grown on Si give clear evidence for such spontaneous superlattice formation.
Date:
October 19, 1998
Creator:
Chason, E.; Floro, J. A.; Follstaedt, D. M.; Lagally, M. G.; Liu, F.; Tersoff, J. et al.
Object Type:
Article
System:
The UNT Digital Library