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Polk County Enterprise (Livingston, Tex.), Vol. 121, No. 22, Ed. 1 Sunday, March 16, 2003
Semi-weekly newspaper from Livingston, Texas that includes local, state and national news along with advertising.
Date:
March 16, 2003
Creator:
White, Barbara
Object Type:
Newspaper
System:
The Portal to Texas History
Archer County News (Archer City, Tex.), No. 3, Ed. 1 Thursday, January 16, 2003
Weekly newspaper from Archer City, Texas that includes local, state, and national news along with advertising.
Date:
January 16, 2003
Creator:
Lewis, Shelley
Object Type:
Newspaper
System:
The Portal to Texas History
Archer County News (Archer City, Tex.), No. 42, Ed. 1 Thursday, October 16, 2003
Weekly newspaper from Archer City, Texas that includes local, state, and national news along with advertising.
Date:
October 16, 2003
Creator:
Lewis, Shelley
Object Type:
Newspaper
System:
The Portal to Texas History
Hondo Anvil Herald (Hondo, Tex.), Vol. 117, No. 3, Ed. 1 Thursday, January 16, 2003
Weekly newspaper from Hondo, Texas that includes local, state, and national news along with extensive advertising.
Date:
January 16, 2003
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Identification of the non-pertechnetate species in Hanford waste tanks, Tc(I) carbonyl complexes
Immobilization of the high-level nuclear waste stored at the Hanford Reservation has been complicated by the presence of soluble, lower-valent technetium species. Previous work by Schroeder and Blanchard has shown that these species cannot be removed by ion-exchange and are difficult to oxidize. The Tc-K edge XANES spectra of the species in Tanks SY-101 and SY-103 were reported by Blanchard, but they could not be assigned to any known technetium complex. We report that the XANES spectra are most likely those of Tc(I) carbonyl species, especially fac-Tc(CO){sub 3}(gluconate){sup 2-}. This is further supported by EXAFS and {sup 99}Tc-NMR studies in nonradioactive simulants of these tank wastes.
Date:
October 16, 2003
Creator:
Lukens, Wayne W.; Shuh, David K.; Schroeder, Norman C. & Ashley, Kenneth R.
Object Type:
Article
System:
The UNT Digital Library
Atomic Scale Chemical and Structural Characterization of Ceramic Oxide Heterostructure Interfaces
The research plan was divided into three tasks: (a) growth of oxide heterostructures for interface engineering using standard thin film deposition techniques, (b) atomic level characterization of oxide heterostructure using such techniques as STEM-2 combined with AFM/STM and conventional high-resolution microscopy (HRTEM), and (c) property measurements of aspects important to oxide heterostructures using standard characterization methods, including dielectric properties and dynamic cathodoluminescence measurements. Each of these topics were further classified on the basis of type of oxide heterostructure. Type I oxide heterostructures consisted of active dielectric layers, including the materials Ba{sub x}Sr{sub 1-x}TiO{sub 3} (BST), Y{sub 2}O{sub 3} and ZrO{sub 2}. Type II heterostructures consisted of ferroelectric active layers such as lanthanum manganate and Type III heterostructures consist of phosphor oxide active layers such as Eu-doped Y{sub 2}O{sub 3}.
Date:
April 16, 2003
Creator:
Singh, R. K.
Object Type:
Report
System:
The UNT Digital Library
Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report
To improve the hot corrosion resistance of YSZ thermal barrier coatings, a 25 {micro}m and a 2 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray and by sol-gel coating method, respectively, onto to the surface of YSZ coating. Indenter test was employed to investigate the spalling of YSZ with and without Al{sub 2}O{sub 3} overlay after hot corrosion. The results showed that Al{sub 2}O{sub 3} overlay acted as a barrier against the infiltration of the molten salt into the YSZ coating during exposure, thus significantly reduced the amount of M-phase of ZrO{sub 2} in YSZ coating. However, a thick Al{sub 2}O{sub 3} overlay was harmful for TBC by increasing compressive stress which causes crack and spalling of YSZ coating. As a result, a dense and thin Al{sub 2}O{sub 3} overlay is critical for simultaneously preventing YSZ from hot corrosion and spalling. In the next reporting period, we will measure or calculate the residue stress within Al{sub 2}O{sub 3} overlay and YSZ coating to study the mechanism of effect of Al{sub 2}O{sub 3} overlay on spalling of YSZ coating.
Date:
December 16, 2003
Creator:
Mao, Scott X.
Object Type:
Report
System:
The UNT Digital Library
Electrochemical performance of Sol-Gel synthesized LiFePO{sub 4} in lithium batteries
LiFePO{sub 4}, Li{sub 0.98}Mg{sub 0.01}FePO{sub 4}, and Li{sub 0.96}Ti{sub 0.01}FePO{sub 4} were synthesized via a sol-gel method, using a variety of processing conditions. For comparison, LiFePO{sub 4} was also synthesized from iron acetate by a solid state method. The electrochemical performance of these materials in lithium cells was evaluated and correlated to mean primary particle size and residual carbon structure in the LiFePO{sub 4} samples, as determined by Raman microprobe spectroscopy. For materials with mean agglomerate sizes below 20 {micro}m, an association between structure and crystallinity of the residual carbon and improved utilization was observed. Addition of small amounts of organic compounds or polymers during processing results in carbon coatings with higher graphitization ratios and better electronic properties on the LiFePO{sub 4} samples and improves cell performance in some cases, even though total carbon contents remain very low (<2%). In contrast, no performance enhancement was seen for samples doped with Mg or Ti. These results suggest that it should be possible to design high power LiFePO{sub 4} electrodes without unduly compromising energy density by optimizing the carbon coating on the particles.
Date:
June 16, 2003
Creator:
Hu, Yaoqin; Doeff, Marca M.; Kostecki, Robert & Finones, Rita
Object Type:
Article
System:
The UNT Digital Library
Breazeale Reactor Modernization Program
The Penn State Breazeale Nuclear Reactor is the longest operating licensed research reactor in the nation. The facility has played a key role in educating scientists, engineers and in providing facilities and services to researchers in many different disciplines. In order to remain a viable and effective research and educational institution, a multi-phase modernization project was proposed. Phase I was the replacement of the 25-year old reactor control and safety system along with associated wiring and hardware. This phase was fully funded by non-federal funds. Tasks identified in Phases II-V expand upon and complement the work done in Phase I to strategically implement state-of-the-art technologies focusing on identified national needs and priorities of the future.
Date:
April 16, 2003
Creator:
Davison, C. C.
Object Type:
Report
System:
The UNT Digital Library
Atmospheric Corrosion and Precipitation Runoff From Zinc and Zinc Alloys Surfaces
The long-term atmospheric corrosion performance of rolled zinc and three thermal-sprayed (TS) zinc materials (Zn, Zn-15Al, and Al-12Zn-0.2In) was characterized by measuring corrosion product concentrations in precipitation runoff at coastal marine and inland sites. Corrosion rates and average zinc concentrations in the runoff were greater at the site having higher annual rainfall. Higher chloride concentrations did not seem to affect either the corrosion rates or the zinc concentrations in the runoff at the coastal site compared to those of the inland site. Zinc runoff concentrations were higher for TS Zn than rolled zinc due to the greater surface area of the thermal-sprayed surface. Average cumulative zinc runoff losses for the two sites were: 64 {micro}mol Zn/L for TS Zn, 37 {micro}mol Zn/L for rolled Zn, 24 {micro}mol Zn/L for TS Zn-15Al, and 1.8 {micro}mol Zn/L for TS Al-12Zn-0.2In. Cumulative zinc runoff losses were directly related both to the precipitation rate and to the availability of Zn in metal surfaces, a consequence of surface roughness and surface chemistry properties of the metal.
Date:
March 16, 2003
Creator:
Matthes, S. A.; Cramer, S. D.; Bullard, S. J.; Covino, B. S., Jr. & Holcomb, G. R.
Object Type:
Article
System:
The UNT Digital Library
LONG-TERM MONITORING SENSOR NETWORK
Long-term monitoring (LTM) associated with subsurface contamination sites is a key element of Long Term Stewardship and Legacy Management across the Department of Energy (DOE) complex. However, both within the DOE and elsewhere, LTM is an expensive endeavor, often exceeding the costs of the remediation phase of a clean-up project. The primary contributors to LTM costs are associated with labor. Sample collection, storage, preparation, analysis, and reporting can add a significant financial burden to project expense when extended over many years. Development of unattended, in situ monitoring networks capable of providing quantitative data satisfactory to regulatory concerns has the potential to significantly reduce LTM costs. But survival and dependable operation in a difficult environment is a common obstacle to widespread use across the DOE complex or elsewhere. Deploying almost any sensor in the subsurface for extended periods of time will expose it to chemical and microbial degradation. Over the time-scales required for in situ LTM, even the most advanced sensor systems may be rendered useless. Frequent replacement or servicing (cleaning) of sensors is expensive and labor intensive, offsetting most, if not all, of the cost savings realized with unattended, in situ sensors. To enable facile, remote monitoring of contaminants and …
Date:
October 16, 2003
Creator:
Farrington, Stephen P.; Haas, John W. & Wyck, Neal Van
Object Type:
Report
System:
The UNT Digital Library
FEASIBILITY OF LARGE-SCALE OCEAN CO2 SEQUESTRATION
This report describes research conducted between July 1, 2003 and September 30, 2003 on the use of dry regenerable sorbents for concentration of carbon dioxide from flue gas. Based on 5-cycle fixed bed tests of grade 3 sodium bicarbonate, calcination in carbon dioxide at 160 C does not affect the activity or capacity of the sorbent in subsequent carbonation cycles. Increasing the calcination temperature to 200 C does have an adverse impact on sorbent performance. RTI produced a supported sorbent with a nominal composition of 40% sodium carbonate. While this material has good attrition resistance, the activity, as determined by thermogravimetry, fixed bed testing and analysis of physical properties is insufficient for use as a carbon dioxide sorbent.
Date:
December 16, 2003
Creator:
Brewer, Peter & Barry, James
Object Type:
Report
System:
The UNT Digital Library
Heavy quark energy loss in nuclear medium
Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark.
Date:
September 16, 2003
Creator:
Zhang, Benr-Wei; Wang, Enke & Wang, Xin-Nian
Object Type:
Article
System:
The UNT Digital Library
Laboratory Evaluation of an Electrochemical Noise System for Detection of Localized and General Corrosion of Natural Gas Transmission Pipelines
Gas transmission pipelines are susceptible to both internal (gas side) and external (soil side) corrosion attack. Internal corrosion is caused by the presence of salt laden moisture, CO{sub 2}, H{sub 2}S, and perhaps O{sub 2} in the natural gas. Internal corrosion usually manifests itself as general corrosion. However, the presence of chlorides in entrained water also can lead to pitting corrosion damage. The electrochemical noise technique can differentiate general from localized corrosion and provide estimates of corrosion rates without external perturbation of the corroding system. It is increasingly being applied to field and industrial installations for in situ corrosion monitoring. It has been used here to determine its suitability for monitoring internal and external corrosion damage on gas transmission pipelines. Corrosion measurements were made in three types of environments: (1) aqueous solutions typical of those found within gas pipelines in equilibrium with th e corrosive components of natural gas; (2) biologically-active soils typical of wetlands; and (3) a simulated, unpressurized, internal gas/liquid gas pipeline environment. Multiple sensor designs were evaluated in the simulated pipe environment. Gravimetric measurements were conducted in parallel with the electrochemical noise measurements to validate the results.
Date:
March 16, 2003
Creator:
Bullard, S. J.; Covino, B. S., Jr.; Russell, J. H.; Holcomb, G. R.; Cramer, S. D.; Ziomek-Moroz, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Impermeable Thin Al2O3 Overlay for TBC Protection From Sulfate and Vanadate Attack in Gas Turbines Quarterly Report
To improve the hot corrosion resistance of YSZ thermal barrier coatings, a 25 {micro}m and a 2 {micro}m thick Al{sub 2}O{sub 3} overlay were deposited by HVOF thermal spray and by sol-gel coating method, respectively, onto to the surface of YSZ coating. Indenter test was employed to investigate the spalling of YSZ with and without Al{sub 2}O{sub 3} overlay after hot corrosion. The results showed that Al{sub 2}O{sub 3} overlay acted as a barrier against the infiltration of the molten salt into the YSZ coating during exposure, thus significantly reduced the amount of M-phase of ZrO{sub 2} in YSZ coating. However, a thick Al{sub 2}O{sub 3} overlay was harmful for TBC by increasing compressive stress which causes crack and spalling of YSZ coating. As a result, a dense and thin Al{sub 2}O{sub 3} overlay is critical for simultaneously preventing YSZ from hot corrosion and spalling. In the next reporting period, we will measure or calculate the residue stress within Al{sub 2}O{sub 3} overlay and YSZ coating to study the mechanism of effect of Al{sub 2}O{sub 3} overlay on spalling of YSZ coating.
Date:
December 16, 2003
Creator:
Mao, Scott X.
Object Type:
Report
System:
The UNT Digital Library
Role of Ash Deposits in the High Temperature Corrosion of Boiler Tubes
Ash deposits cause accelerated corrosion of waterwall boiler tubes in waste to energy (WTE) incinerators. To study this effect, a series of experiments were planned to determine the mechanism of corrosion of carbon steel boiler tubes under ash deposits. Results reported here were for carbon steel tubes exposed to an environment consisting of O{sub 2}, CO{sub 2}, N{sub 2}, and water vapor. Future experiments will include HCl and SO{sub 2}. Test procedures included both isothermal and thermal gradient tests. Temperatures ranged from 300 C to 510 C for the isothermal tests and a metal/gas temperature of 450/670 C for the thermal gradient test. Initial results indicated that increasing temperature caused the isothermal corrosion rates of ash-covered samples to increase. A shakedown test of a thermal gradient test apparatus was conducted at a metal/gas temperature of 450/670 C, a more severe environment than normally encountered in WTE waterwalls. Results showed that the corrosion rate under those conditions exceeds the isothermal corrosion rates at the same metal temperature by a factor of 2 or more.
Date:
March 16, 2003
Creator:
Covino, B. S., Jr.; Russell, J. H.; Cramer, S. D.; Holcomb, G. R.; Bullard, S. J.; Ziomek-Moroz, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Wafer Bonding and Epitaxial Transfer of GaSb-based Epitaxy to GaAs for Monolithic Interconnection of Thermophotovoltaic Devices
GaInAsSb/AlGaAsSb/InAsSb/GaSb epitaxial layers were bonded to semi-insulating GaAs handle wafers with SiO{sub x}/Ti/Au as the adhesion layer for monolithic interconnection of thermophotovoltaic (TPV) devices. Epitaxial transfer was completed by removal of the GaSb substrate, GaSb buffer, and InAsSb etch-stop layer by selective chemical etching. The SiO{sub x}/TiAu provides not only electrical isolation, but also high reflectivity and is used as an internal back-surface reflector. Characterization of wafer-bonded epitaxy by high-resolution x-ray diffraction and time-decay photoluminescence indicates minimal residual stress and enhancement in optical quality. 0.54-eV GaInAsSb cells were fabricated and monolithically interconnected in series. A 10-junction device exhibited linear voltage building with an open-circuit voltage of 1.8 V.
Date:
June 16, 2003
Creator:
Wang, C. A.; Shiau, D. A.; Murphy, P. G.; O'brien, P. W.; Huang, R. K.; Connors, M. K. et al.
Object Type:
Report
System:
The UNT Digital Library
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sqrt(sNN) = 200 GeV
Identified mid-rapidity particle spectra of {pi}{sup {+-}}, K{sup {+-}}, and p({bar p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R{sub dAu}) between (p+ {bar p}) and charged hadrons (h) in the transverse momentum range 1.2 < p{sub T} < 3.0 GeV/c is measured to be 1.19 {+-} 0.05(stat) {+-} 0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + {bar p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.
Date:
September 16, 2003
Creator:
Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type:
Article
System:
The UNT Digital Library
TOP500 Supercomputers for November 2003
22nd Edition of TOP500 List of World s Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 22nd edition of the TOP500 list of the worlds fastest supercomputers was released today (November 16, 2003). The Earth Simulator supercomputer retains the number one position with its Linpack benchmark performance of 35.86 Tflop/s (''teraflops'' or trillions of calculations per second). It was built by NEC and installed last year at the Earth Simulator Center in Yokohama, Japan.
Date:
November 16, 2003
Creator:
Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack & Simon, Horst D.
Object Type:
Report
System:
The UNT Digital Library
Longevity of Emplacement Drift Ground Support Materials for LA
The purpose of this analysis report is to evaluate and document the inclusion or exclusion of the disruptive events features, events, and processes (FEPs) with respect to modeling used to support the total system performance assessment for license application (TSPA-LA). A screening decision, either ''Included'' or ''Excluded,'' is given for each FEP, along with the technical basis for screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d), (e), and (f) [DIRS 156605]. The FEPs addressed in this report deal with both seismic and igneous disruptive events, such as fault displacements through the repository and an igneous intrusion into the repository. For included FEPs, this analysis summarizes the implementation of the FEP in TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded). Previous versions of this report were developed to support the total system performance assessments (TSPA) for various prior repository designs. This revision addresses the repository design for the license application (LA).
Date:
September 16, 2003
Creator:
Tang, D.
Object Type:
Report
System:
The UNT Digital Library
An Examination of Rebuild America Partnership Accomplishments and the Factors Influencing Them
The Rebuild America program was established in 1994 to accelerate the adoption of energy efficiency measures and practices in existing public facilities, commercial buildings, and multifamily housing units. More recently, the program has expanded to include new construction as well. The program encourages the formation of partnerships involving state and local governments, private businesses, and other organizations to help identify and solve problems related to energy use in buildings. Rebuild America does not directly fund actual building improvements. Instead, it provides the Rebuild Partners with the technical tools and assistance they need to plan and implement building projects and stimulates other entities to make substantial investments in energy efficiency. At the request of the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy, staff at Oak Ridge National Laboratory studied the Rebuild America program for the purpose of identifying key factors associated with successful operations. Substantial amounts of data were collected directly from Rebuild America partnerships concerning the results achieved by each of their individual projects, both committed and completed. In addition, data were collected from secondary sources on a limited number of factors describing partnership setting and characteristics. By combining these two data sets, we were able …
Date:
October 16, 2003
Creator:
Schweitzer, M.
Object Type:
Report
System:
The UNT Digital Library
HTGR Unit Fuel Pebble k-infinity Results Using Chord Length Sampling
There is considerable interest in transport models that will permit the simulation of neutral particle transport through stochastic mixtures. Chord length sampling techniques that simulate particle transport through binary stochastic mixtures consisting of spheres randomly arranged in a matrix have been implemented in several Monte Carlo Codes [1-3]. Though the use of these methods is growing, the accuracy and efficiency of these methods has not yet been thoroughly demonstrated for an application of particular interest--a high temperature gas reactor fuel pebble element. This paper presents comparison results of k-infinity calculations performed on a LEUPRO-1 pebble cell. Results are generated using a chord length sampling method implemented in a test version of MCNP [3]. This Limited Chord Length Sampling (LCLS) method eliminates the need to model the details of the micro-heterogeneity of the pebble. Results are also computed for an explicit pebble model where the TRISO fuel particles within the pebble are randomly distributed. Finally, the heterogeneous matrix region of the pebble cell is homogenized based simply on volume fractions. These three results are compared to results reported by Johnson et al [4], and duplicated here, using a cubic lattice representation of the TRISO fuel particles. Figures of Merit for the …
Date:
June 16, 2003
Creator:
Donovan, T.J. & Danon, Y.
Object Type:
Report
System:
The UNT Digital Library
Portable Monitor for Tritium in Air
In the handling of tritium associated with heavy water moderator, there is a possibility that some of it, in the form of tritiated hydrogen or water vapor, may become airborne. An instrument is needed which will quantitatively measure tritium in air in order to protect personnel from the radiation hazard associated with tritium. This paper describes a portable air sampler developed to monitor concentrations of tritium in air between 4 x 10-5 and 1600 x 10-5 microcurie per cubic centimeter.
Date:
January 16, 2003
Creator:
Anthony, J.D.
Object Type:
Article
System:
The UNT Digital Library
2001 - 2002 Upper Three Runs Sequence of Earthquakes at the SRS, South Carolina
On October 08, 2001 a small felt earthquake occurred near Upper Three Runs Creek in the north central area of the Savannah River Site, South Carolina. Seven very small aftershocks followed the main event with the last one occurring March 06, 2002. All activity occurred within a small area. Further analysis of collected data indicates a correlation of this low level seismic activity with a small northwest trending structure observed in detailed gravity and magnetic data. Both single event and composite focal mechanisms were derived using local and regional stations. Results indicated predominantly dip-slip motion along a fault striking NNW at 335 degrees and dipping 41 degrees to the southwest. A 3D plot of the eight hypocenters clearly defines a fault plane nearly analogous to that obtained from the focal solutions. The Upper Three Runs series of events is another example of a separate class of earthquakes that occur within the central Piedmont and upper Coastal Plain of South Carolina. The Upper Three Runs sequence of events demonstrates that shallow intersections of structures interpreted from potential field data can be the foci for localized stress concentrations where microearthquake activity can occur. These earthquakes are attributable to small scale faults associated …
Date:
October 16, 2003
Creator:
Stevenson, Donald A.
Object Type:
Article
System:
The UNT Digital Library