Cognitive models applied to human effectiveness in national security environments (ergonomics of augmented cognition system design and application). (open access)

Cognitive models applied to human effectiveness in national security environments (ergonomics of augmented cognition system design and application).

In complex simulation systems where humans interact with computer-generated agents, information display and the interplay of virtual agents have become dominant media and modalities of interface design. This design strategy is reflected in augmented reality (AR), an environment where humans interact with computer-generated agents in real-time. AR systems can generate large amount of information, multiple solutions in less time, and perform far better in time-constrained problem solving. The capabilities of AR have been leveraged to augment cognition in human information processing. In this sort of augmented cognition (AC) work system, while technology has become the main source for information acquisition from the environment, the human sensory and memory capacities have failed to cope with the magnitude and scale of information they encounter. This situation generates opportunity for excessive cognitive workloads, a major factor in degraded human performance. From the human effectiveness point of view, research is needed to develop, model, and validate simulation tools that can measure the effectiveness of an AR technology used to support the amplification of human cognition. These tools will allow us to predict human performance for tasks executed under an AC tool construct. This paper presents an exploration of ergonomics issues relevant to AR and …
Date: June 1, 2004
Creator: Ntuen, Celestine (North Carolina Agricultural and Technical State University, Greensboro, NC) & Winchester, Woodrow III (North Carolina Agricultural and Technical State University, Greensboro, NC)
Object Type: Report
System: The UNT Digital Library
Colloid and Colloid-Facilitated Contaminant Transport Experiments and Models to Support Assessments of Radionuclide Migration at Yucca Mountain and the Nevada Test Site (open access)

Colloid and Colloid-Facilitated Contaminant Transport Experiments and Models to Support Assessments of Radionuclide Migration at Yucca Mountain and the Nevada Test Site

In recent years, numerous laboratory and field experiments have been conducted to assess and parameterize colloid and colloid-facilitated radionuclide transport for the Yucca Mountain Project and the Nevada Test Site (NTS) Environmental Restoration Project. Radionuclide contamination of ground water currently exists within or near underground nuclear test cavities at the NTS, and the proposed Yucca Mountain high-level nuclear waste repository represents a potential future source of radionuclide contamination of ground water at the NTS. Furthermore, recent field observations have indicated that small amounts of Plutonium, which normally adsorbs very strongly to mineral surfaces in aquifers, can transport quite rapidly and over significant distances in ground water when associated with inorganic colloids (Kersting et al., 1999). Groundwater samples from all over the Nevada Test Site have been analyzed for colloid concentrations and size distributions, and it is clear that there are significant mass loadings of colloids in the ground water at some locations. These colloids represent mobile surface area for potentially transporting strongly-adsorbed radionuclides. Field transport experiments have involved the use of fluorescent-dyed carboxylate-modified latex (CML) microspheres in the 250- to 650-nm diameter size range as surrogates for natural colloids in forced-gradient tracer tests. These experiments have indicated that effective colloid …
Date: June 1, 2004
Creator: Reimus, P.
Object Type: Report
System: The UNT Digital Library
Colloid-Facilitated Plutonium Transport in Saturated Alluvium (open access)

Colloid-Facilitated Plutonium Transport in Saturated Alluvium

Natural groundwater colloids have been recognized as possible agents for enhancing the subsurface transport of strongly-sorbing radionuclides. To evaluate this mechanism, packed-bed column experiments were conducted comparing the simultaneous transport of dissolved plutonium (Pu), Pu sorbed onto natural colloids, 190-nm and 500-nm diameter fluorescent CML microspheres, and tritiated water in saturated alluvium. Experiments were conducted in two columns having slightly different porosities at two flow rates, resulting in average linear velocities (v{sub z}) of 0.6 to 3.65 cm/hr in one column and 0.57 to 2.85 cm/hr in the other. In all experiments, Pu associated with natural colloids transported through alluvium essentially unretarded, while dissolved Pu was entirely retained. These results were consistent with the strong sorption of Pu to alluvium and the negligible desorption from natural colloids, observed in separate batch experiments, over time scales exceeding those of the column experiments. Breakthroughs of natural colloids preceded tritiated water in all experiments, indicating a slightly smaller effective pore volume for the colloids. The enhancement of colloids transport over tritiated water decreased with v{sub z}, implying {approx} 40% enhancement at v{sub z} = 0. The 500-nm CML microspheres were significantly attenuated in the column experiments compared to the 190-nm microspheres, which exhibited …
Date: June 1, 2004
Creator: Abdel-Fattah, A.; Reimus, P.; Ware, S. & Haga, M.
Object Type: Report
System: The UNT Digital Library
Combined Extraction of Cesium, Strontium, and Actinides from Alkaline Media : An Extension of the Caustic-Side Solvent Extraction (CSSX) Process Technology (open access)

Combined Extraction of Cesium, Strontium, and Actinides from Alkaline Media : An Extension of the Caustic-Side Solvent Extraction (CSSX) Process Technology

This fundamental research on combined cesium, strontium, and actinide separation from alkaline media by solvent extraction addresses the EM need for more efficient processes for the combined separation of these elements. The goal of this research is to obtain fundamental information for the development of more efficient processes for the combined separation of cesium, strontium, and transuranic elements from high level waste within the U.S. Department of Energy's (U.S. DOE) complex. These improved processes are targeted primarily for treating the wastes present at the U.S. DOE's Hanford and Savannah River sites. Combined separation of the radionuclides from these wastes would permit disposal of the treated waste as low-level waste, significantly reducing the volume of high level waste. Solvent extraction using the calixarene-based CSSX process has been shown to be a very effective separation method for cesium removal from High Level Waste (HLW) present at the U.S. DOE's Savannah River Site (SRS).
Date: June 1, 2004
Creator: Delmau, Laetitia H.; Hobbs, David T. & Raymond, Kenneth N.
Object Type: Report
System: The UNT Digital Library
Commentary: Air-conditioning as a risk for increased use of healthservices (open access)

Commentary: Air-conditioning as a risk for increased use of healthservices

In this issue of the journal, Preziosi et al. [2004] report the first study to assess differences in the utilization of health care related to the presence of air-conditioning in office workplaces. Although the study was simple and cross-sectional, the data variables from questionnaires, and the findings subject to a variety of questions, the findings are striking enough to deserve clarification. The study used a large random national sample of French women assembled for another purpose (to study antioxidant nutrients and prevention of cancer and cardiovascular disease). Participants reported health services and health events in monthly questionnaires over 1 year, and in one questionnaire in the middle of that period also reported whether air-conditioning was in use at their workplace. Fifteen percent of participants reported air-conditioning at work. Analyses adjusting for age and smoking status of participants found increases in most outcomes assessed: use of specific kinds of physicians, sickness absence, and hospital stays. While the increases in odds ratios (OR) and 95% confidence intervals (CI) were statistically significant for only otorhinolaryngology [OR (95% CI) = 2.33 (1.35-4.04)] and sickness absence [1.70 (1.13-2.58)], other increases were notable--dermatology [1.6 (0.98-2.65)]; hospital stay [1.51 (0.92-2.45)], and pneumonology [2.10 (0.65-6.82)]. The least elevated …
Date: June 1, 2004
Creator: Mendell, Mark J.
Object Type: Article
System: The UNT Digital Library
Commissioning of the superconducting ECR ion source VENUS at 18 GHz (open access)

Commissioning of the superconducting ECR ion source VENUS at 18 GHz

During the last year, the VENUS ECR ion source was commissioned at 18 GHz and preparations for 28 GHz operation are now underway. During the commissioning phase with 18 GHz, tests with various gases and metals have been performed with up to 2000 W RF power. The ion source performance is very promising [1,2]. VENUS (Versatile ECR ion source for Nuclear Science) is a next generation superconducting ECR ion source, designed to produce high current, high charge state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the RIA (Rare Isotope Accelerator) front end. The goal of the VENUS ECR ion source project as the RIA R&D injector is the production of 240e{micro}A of U{sup 30+}, a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5e{micro}A of U{sup 48+}, a low current, very high charge state beam. To meet these ambitious goals, VENUS has been designed for optimum operation at 28 GHz. This frequency choice has several design consequences. To achieve the required magnetic confinement, superconducting magnets have to be used. …
Date: June 1, 2004
Creator: Leitner, Daniela; Abbott, Steven R.; Dwinell, Roger D.; Leitner, Matthaeus; Taylor, Clyde E. & Lyneis, Claude M.
Object Type: Report
System: The UNT Digital Library
Complete mitochondrial genome sequence of Urechis caupo, a representative of the phylum Echiura (open access)

Complete mitochondrial genome sequence of Urechis caupo, a representative of the phylum Echiura

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Date: June 1, 2004
Creator: Boore, Jeffrey L.
Object Type: Article
System: The UNT Digital Library
Composition, Reactivity and Regulation of Extracellular Metal-Reducing Structures (Bacterial Nanowires) Produced by Dissimilatory Metal - Reducing Bacteria (open access)

Composition, Reactivity and Regulation of Extracellular Metal-Reducing Structures (Bacterial Nanowires) Produced by Dissimilatory Metal - Reducing Bacteria

Approach. Previously, using conventional and cryoTEM techniques, surface physicochemistry assays, NMR structural analysis, etc., we showed that the structure and composition of Shewanella's lipopolysaccharide (LPS) and capsular polysaccharide (PS) significantly determined overall cell surface physicochemistry. In our study a strong correlation between such macroscopic parameters as surface electronegativity, hydrophobicity or hydrophilicity, and bacterial adhesion to hematite was observed. Rough LPS strains exhibited more than an order higher affinity and maximal sorption capacity to hematite when compared to encapsulated strains. These general trends, however, characterize bacterial adhesion only as a bulk process, being unable to reveal finer mechanisms taking place at the level of an individual cell. Cell surface physicochemical and structural heterogeneity suggests much more complex interactions at the bacterial-mineral interface than predicted by such approaches operating within macroscopic parameters.
Date: June 1, 2004
Creator: Beveridge, Terrance J.
Object Type: Report
System: The UNT Digital Library
A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite (Project No.: 81959) (open access)

A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite (Project No.: 81959)

NO3 cancrinite and NO3 sodalite haves been found as a common sodium alumino-silicate forming in strongly caustic and alkaline aqueous solutions associated with radioactive High Level Waste (HLW) stored in many underground tanks and also in nuclear waste treatment facilities such as the Savannah River Site (SRS). The appearance of these phases have created very expensive problems in waste treatment plants by fouling process evaporators in the SRS waste processing facility. Therefore, in order to prevent their formation an assessment of the relative stability, formation kinetics, and the ion-exchange characteristics of these two phases in HLW solutions needs to be investigated. The goals of this project are to: (1) Develop a robust equilibrium thermodynamic framework to accurately describe the formation of NO3 cancrinite and NO3 sodalite. (2) Provide quantification and characterization of the solid precipitation rates through long-term batch kinetic experiments and novel analytical techniques. (3) Investigate the partitioning and ion exchange properties of these zeolitic phases with respect to radionuclides and RCRA metal species. This also includes compositional and structural characterization of ion exchanged solids elucidate the exchange properties of these phases.
Date: June 1, 2004
Creator: Colon, Carlos F. Jove; Navrotsky, Alexandra; Krumhansl, James L.; Nyman, May & Liu, Qingyuan
Object Type: Report
System: The UNT Digital Library
Compressed air energy storage monitoring to support refrigerated mined rock cavern technology. (open access)

Compressed air energy storage monitoring to support refrigerated mined rock cavern technology.

This document is the final report for the Compressed Air Energy Storage Monitoring to Support Refrigerated-Mined Rock Cavern Technology (CAES Monitoring to Support RMRCT) (DE-FC26-01NT40868) project to have been conducted by CAES Development Co., along with Sandia National Laboratories. This document provides a final report covering tasks 1.0 and subtasks 2.1, 2.2, and 2.5 of task 2.0 of the Statement of Project Objectives and constitutes the final project deliverable. The proposed work was to have provided physical measurements and analyses of large-scale rock mass response to pressure cycling. The goal was to develop proof-of-concept data for a previously developed and DOE sponsored technology (RMRCT or Refrigerated-Mined Rock Cavern Technology). In the RMRCT concept, a room and pillar mine developed in rock serves as a pressure vessel. That vessel will need to contain pressure of about 1370 psi (and cycle down to 300 psi). The measurements gathered in this study would have provided a means to determine directly rock mass response during cyclic loading on the same scale, under similar pressure conditions. The CAES project has been delayed due to national economic unrest in the energy sector.
Date: June 1, 2004
Creator: Lee, Moo Yul & Bauer, Stephen J.
Object Type: Report
System: The UNT Digital Library
COMPUTATIONAL FLUID DYNAMICS BASED INVESTIGATION OF SENSITIVITY OF FURNACE OPERATIONAL CONDITIONS TO BURNER FLOW CONTROLS (open access)

COMPUTATIONAL FLUID DYNAMICS BASED INVESTIGATION OF SENSITIVITY OF FURNACE OPERATIONAL CONDITIONS TO BURNER FLOW CONTROLS

This is the extended second Semiannual Technical Report for DOE Cooperative Agreement No: DE-FC26-02NT41580. The goal of this project is to systematically assess the sensitivity of furnace operational conditions to burner air and fuel flows in coal fired utility boilers. Our approach is to utilize existing baseline furnace models that have been constructed using Reaction Engineering International's (REI) computational fluid dynamics (CFD) software. Using CFD analyses provides the ability to carry out a carefully controlled virtual experiment to characterize the sensitivity of NOx emissions, unburned carbon (UBC), furnace exit CO (FECO), furnace exit temperature (FEGT), and waterwall deposition to burner flow controls. The Electric Power Research Institute (EPRI) is providing co-funding for this program, and instrument and controls experts from EPRI's Instrument and Controls (I&C) Center are active participants in this project. This program contains multiple tasks and good progress is being made on all fronts.
Date: June 1, 2004
Creator: Cremer, Marc; Chen, Zumao; Wang, Dave & Wolff, Paul
Object Type: Report
System: The UNT Digital Library
Concentrator Photovoltaic Qualification Standards for Systems Using Refractive and Reflective Optics: Preprint (open access)

Concentrator Photovoltaic Qualification Standards for Systems Using Refractive and Reflective Optics: Preprint

This paper describes a proposed international qualification standard for photovoltaic (PV) systems generating electricity from concentrated sunlight. The standard's purpose is to provide stress tests and procedures to identify any component weaknesses in a system. If no weaknesses are identified during qualification, both the manufacturer and the customer can expect a more reliable product. In 2002, we began developing the standard, under the auspices of the International Electrotechnical Commission (IEC), that would describe testing procedures for concentrator PV systems using reflecting (mirrors) or refractive (lenses) optics for focusing sunlight onto solar cells. The initial draft of the IEC standard was based on the first concentrator PV qualification standard published by the Institute of Electrical and Electronics Engineers (IEEE) in the United States in 2001. Well-developed U.S. concentrator technologies use refractive optics, and the IEEE standard needed improvement for testing systems with reflective optics. Furthermore, with record III-V solar cell efficiencies above 37%, concentrator PV developers around the world would like to incorporate such cells into their next generation of technologies. The paper will highlight significant differences between the proposed IEC standard and the earlier IEEE standard.
Date: June 1, 2004
Creator: McConnell, R.; Ji, L.; Lasich, J. & Mansfield, R.
Object Type: Article
System: The UNT Digital Library
Concordant lipoprotein and weight responses to dietary fat changein identical twins with divergent exercise levels (open access)

Concordant lipoprotein and weight responses to dietary fat changein identical twins with divergent exercise levels

Background/Objective: The purpose of this study is to testthe extent that individual lipoprotein responses to diet can beattributed to genes in the presence of divergent exercise levels.Design:Twenty-eight pairs of male monozygotic twins (one mostly sedentary, theother running an average of 50 km/week more than the sedentary twin) wentfrom a 6-week 40 percent fat diet to a 6-week 20 percent fat diet in acrossover design. The diets reduced fat primarily by reducing saturatedand polyunsaturated fat (both from 14 percent to 4 percent), whileincreasing carbohydrate intake from 45 percent to 65 percent. Results:Despite the twins' differences in physical activity, the dietarymanipulation produced significantly correlated changes (P<0.05) in thetwin's total cholesterol (r=0.56), low-density lipoprotein(LDL)-cholesterol (r=0.70), large, buoyant LDL (Sf7-12, r=0.52), apo A-I(r=0.49), Lp(a) (r=0.49), electrophoresis measurements of LDL-I (LDLsbetween 26 and 28.5 nm diameter, r=0.48), LDL-IIB (25.2-24.6 nm, r=0.54),LDL-IV (22-24.1 nm, r=0.50), and body weights (r=0.41). Replacing fatswith carbohydrates significantly decreased the size and ultracentrifugeflotation rate of the major LDL, the LDL mass concentrations of Sf7-12,LDL-I, high-density lipoprotein (HDL)-cholesterol and apo A-I, andsignificantly increased LDL-IIIA (24.7-25.5 nm diameter) and Lp(a).Conclusions: Even in the presence of extreme exercise difference, genessignificantly affect changes in LDL, apo A-I, Lp(a) and body weight whendietary fats are replaced …
Date: June 1, 2004
Creator: Williams, Paul T.; Blanche, Patricia J.; Rawlings, Robin & Krauss, Ronald M.
Object Type: Article
System: The UNT Digital Library
Control of Temperature for Health and Productivity Inoffices (open access)

Control of Temperature for Health and Productivity Inoffices

Indoor temperature is one of the fundamental characteristics of the indoor environment. It can be controlled with different accuracy depending on the building and its HVAC system. The purpose of this study was to evaluate the potential benefits of improved temperature control, and apply the information for a cost-benefit analyses. The indoor temperature affects several human responses, including thermal comfort, perceived air quality, sick building syndrome symptoms and performance in work. In this study we focused on the effects of temperature on performance in work. We collected and analyzed the literature relating the performance in work and temperature. The results of multiple studies are relatively consistent and show an average relationship of 2% decrement in work performance per degree C when the temperature is above 25 C. Less data were available on the performance in low temperatures. However, studies show a strong effect on manual tasks with temperatures below thermal neutrality as soon as the temperature of hands decreased due to control of blood flow. When the estimated productivity decrement from elevated temperatures was applied to data from a study of night-time ventilative cooling, the estimated value of productivity improvements were 32 to 120 times greater than the cost of …
Date: June 1, 2004
Creator: Seppanen, Olli; Fisk, William J. & Faulkner, David
Object Type: Article
System: The UNT Digital Library
Corrective Action Investigation Plan for Corrective Action Unit 151: Septic Systems and Discharge Area, Nevada Test Site, Nevada, Rev. No.: 0 (open access)

Corrective Action Investigation Plan for Corrective Action Unit 151: Septic Systems and Discharge Area, Nevada Test Site, Nevada, Rev. No.: 0

This Corrective Action Investigation Plan (CAIP) contains project-specific information for conducting site investigation activities at Corrective Action Unit (CAU) 151: Septic Systems and Discharge Area, Nevada Test Site, Nevada. Information presented in this CAIP includes facility descriptions, environmental sample collection objectives, and criteria for the selection and evaluation of environmental corrective action alternatives. Corrective Action Unit 151 is located in Areas 2, 12, 18, and 20 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 151 is comprised of the nine Corrective Action Sites (CAS) listed below: (1) 02-05-01, UE-2ce Pond; (2) 12-03-01, Sewage Lagoons (6); (3) 12-04-01, Septic Tanks; (4) 12-04-02, Septic Tanks; (5) 12-04-03, Septic Tank; (6) 12-47-01, Wastewater Pond; (7) 18-03-01, Sewage Lagoon; (8) 18-99-09, Sewer Line (Exposed); and (9) 20-19-02, Photochemical Drain. The CASs within CAU 151 are discharge and collection systems. Corrective Action Site 02-05-01 is located in Area 2 and is a well-water collection pond used as a part of the Nash test. Corrective Action Sites 12-03-01, 12-04-01, 12-04-02, 12-04-03, and 12-47-01 are located in Area 12 and are comprised of sewage lagoons, septic tanks, associated piping, and two sumps. The features are a part of …
Date: June 1, 2004
Creator: Strand, David A.
Object Type: Report
System: The UNT Digital Library
Corrective Action Investigation Plan for Corrective Action Unit 551: Area 12 Muckpiles, Nevada Test Site, Nevada, Rev. No.: 0 (open access)

Corrective Action Investigation Plan for Corrective Action Unit 551: Area 12 Muckpiles, Nevada Test Site, Nevada, Rev. No.: 0

This Corrective Action Investigation Plan (CAIP) contains project-specific information including facility descriptions, environmental sample collection objectives, and criteria for conducting site investigation activities at Corrective Action Unit (CAU) 551, Area 12 muckpiles, Nevada Test Site (NTS), Nevada. This CAIP has been developed in accordance with the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996) that was agreed to by the State of Nevada, the U.S. Department of Energy (DOE), and the U.S. Department of Defense. Corrective Action Unit 551 is located in Area 12 of the NTS, which is approximately 110 miles (mi) northwest of Las Vegas, Nevada (Figure 1-1). Area 12 is approximately 40 miles beyond the main gate to the NTS. Corrective Action Unit 551 is comprised of the four Corrective Action Sites (CASs) shown on Figure 1-1 and listed below: (1) 12-01-09, Aboveground Storage Tank and Stain; (2) 12-06-05, Muckpile; (3) 12-06-07, Muckpile; and (4) 12-06-08, Muckpile. Corrective Action Site 12-01-09 is located in Area 12 and consists of an above ground storage tank (AST) and associated stain. Corrective Action Site 12-06-05 is located in Area 12 and consists of a muckpile associated with the U12 B-Tunnel. Corrective Action Site 12-06-07 is located in Area 12 and …
Date: June 1, 2004
Creator: Strand, David A.
Object Type: Report
System: The UNT Digital Library
Corrective Action Investigation Plan for Corrective Action Unit 551: Area 12 Muckpiles, Nevada Test Site, Nevada, Rev. No. 0 (open access)

Corrective Action Investigation Plan for Corrective Action Unit 551: Area 12 Muckpiles, Nevada Test Site, Nevada, Rev. No. 0

This Corrective Action Investigation Plan (CAIP) contains project-specific information including facility descriptions, environmental sample collection objectives, and criteria for conducting site investigation activities at Corrective Action Unit (CAU) 551, Area 12 muckpiles, Nevada Test Site (NTS), Nevada. This CAIP has been developed in accordance with the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996) that was agreed to by the State of Nevada, the U.S. Department of Energy (DOE), and the U.S. Department of Defense. Corrective Action Unit 551 is located in Area 12 of the NTS, which is approximately 110 miles (mi) northwest of Las Vegas, Nevada (Figure 1-1). Area 12 is approximately 40 miles beyond the main gate to the NTS. Corrective Action Unit 551 is comprised of the four Corrective Action Sites (CASs) shown on Figure 1-1 and listed below: (1) 12-01-09, Aboveground Storage Tank and Stain; (2) 12-06-05, Muckpile; (3) 12-06-07, Muckpile; and (4) 12-06-08, Muckpile. Corrective Action Site 12-01-09 is located in Area 12 and consists of an above ground storage tank (AST) and associated stain. Corrective Action Site 12-06-05 is located in Area 12 and consists of a muckpile associated with the U12 B-Tunnel. Corrective Action Site 12-06-07 is located in Area 12 and …
Date: June 1, 2004
Creator: Boehlecke, Robert F.
Object Type: Report
System: The UNT Digital Library
Corrosion prevention of Oregon's reinforced coastal bridges (open access)

Corrosion prevention of Oregon's reinforced coastal bridges

The Oregon Department of Transportation (Oregon DOT) maintains more than 120 coastal bridges; many are reinforced concrete structures over 15 m (50 ft) in length. Twelve of these bridges are historic structures. Oregon DOT is concerned about the ongoing deterioration of these bridges, rising maintenance and repair costs, and the need to protect Oregon’s large investment in coastal bridges. Over 80,000 m2 (850,000 ft2) of coastal bridge surface have been repaired and protected from further chloride-induced corrosion damage by using conductive coating anodes. Most of the anode area is thermal-sprayed (TS) Zn. Other anode materials include TS Ti, Zn-hydrogel, and conductive carbon paint. TS Zn anodes are estimated to have a service life exceeding 25 years but exhibit increasing anode polarization with age. Catalyzed TS Ti anodes develop no significant anode polarization and have exhibited stable long-term performance over 8 years of service. Galvanic Zn-hydrogel anodes produce a stable protection current with no evidence of aging effects over 6 years of service. The conductive carbon paint anode operates at a low anode current density and consumption rate with a low rate of acidification at the anode-concrete interface, which has contributed to a stable protection current over 17 years of service.
Date: June 1, 2004
Creator: Bullard, Sophie J.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Cryer. C.B (Oregon Dept. of Transportation, Salem, OR) et al.
Object Type: Article
System: The UNT Digital Library
Critical Heat Flux in Inclined Rectangular Narrow Gaps (open access)

Critical Heat Flux in Inclined Rectangular Narrow Gaps

In light of the TMI-2 accident, in which the reactor vessel lower head survived the attack by molten core material, the in-vessel retention strategy was suggested to benefit from cooling the debris through a gap between the lower head and the core material. The GAMMA 1D (Gap Apparatus Mitigating Melt Attack One Dimensional) tests were conducted to investigate the critical heat flux (CHF) in narrow gaps with varying surface orientations. The CHF in an inclined gap, especially in case of the downward-facing narrow gap, is dictated by bubble behavior because the departing bubbles are squeezed. The orientation angle affects the bubble layer and escape of the bubbles from the narrow gap. The test parameters include gap sizes of 1, 2, 5 and 10 mm and the open periphery, and the orientation angles range from the fully downward-facing (180o) to the vertical (90o) position. The 15 ×35 mm copper test section was electrically heated by the thin film resistor on the back. The heater assembly was installed to the tip of the rotating arm in the heated water pool at the atmospheric pressure. The bubble behavior was photographed utilizing a high-speed camera through the Pyrex glass spacer. It was observed that …
Date: June 1, 2004
Creator: Kim, Jeong J.; Kim, Yong H.; Kim, Seong J.; Noh, Sang W.; Suh, Kune Y.; Rempe, Joy L. et al.
Object Type: Article
System: The UNT Digital Library
Critical time step for a bilinear laminated composite Mindlin shell element. (open access)

Critical time step for a bilinear laminated composite Mindlin shell element.

The critical time step needed for explicit time integration of laminated shell finite element models is presented. Each layer is restricted to be orthotropic when viewed from a properly oriented material coordinate system. Mindlin shell theory is used in determining the laminated response that includes the effects of transverse shear. The effects of the membrane-bending coupling matrix from the laminate material model are included. Such a coupling matrix arises even in the case of non-symmetric lay-ups of differing isotropic layers. Single point integration is assumed to be used in determining a uniform strain response from the element. Using a technique based upon one from the literature, reduced eigenvalue problems are established to determine the remaining non-zero frequencies. It is shown that the eigenvalue problem arising from the inplane normal and shear stresses is decoupled from that arising from the transverse shear stresses. A verification example is presented where the exact and approximate results are compared.
Date: June 1, 2004
Creator: Hammerand, Daniel Carl
Object Type: Report
System: The UNT Digital Library
Crop Insurance: USDA Needs to Improve Oversight of Insurance Companies and Develop a Policy to Address Any Future Insolvencies (open access)

Crop Insurance: USDA Needs to Improve Oversight of Insurance Companies and Develop a Policy to Address Any Future Insolvencies

A letter report issued by the General Accounting Office with an abstract that begins "U.S. Department of Agriculture's (USDA) Risk Management Agency (RMA) administers the federal crop insurance program in partnership with insurance companies who share in the risk of loss or gain. In 2002, American Growers Insurance Company (American Growers), at the time, the largest participant in the program, was placed under regulatory control by the state of Nebraska. To ensure that policyholders were protected and that farmers' claims were paid, RMA agreed to fund the dissolution of American Growers. To date, RMA has spent about $40 million. GAO was asked to determine (1) what factors led to the failure of American Growers, (2) whether RMA procedures were adequate to monitor companies' financial condition, and (3) how effectively and efficiently RMA handled the dissolution of American Growers."
Date: June 1, 2004
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Cross-sectional relationships of exercise and age to adiposity in60,617 male runners (open access)

Cross-sectional relationships of exercise and age to adiposity in60,617 male runners

The objective of this report is to assess in men whether exercise affects the estimated age-related increase in adiposity, and contrariwise, whether age affects the estimated exercise-related decrease in adiposity. Cross-sectional analyses of 64,911 male runners who provided data on their body mass index (97.6 percent), waist (91.1 percent), hip (47.1 percent), and chest circumferences (77.9 percent). Between 18 to 55 years old, the decline in BMI with weekly distance run (slope+-SE) was significantly greater in men 25-55 years old (slope+-:-0.036+-0.001 kg/m2 per km/wk) than in younger men (-0.020+-0.002 kg/m 2 per km/wk). Declines in waist circumference with running distance were also significantly greater in older than younger men (P&lt;10-9 for trend),i.e., the slopes decreased progressively from -0.035+-0.004 cm per km/wk in 18-25 year old men to -0.097+-0.003 cm per km/wk in 50-55 year old men. Increases in BMI with age were greater for men who ran under 16km/wk than for longer distance runners. Waist circumference increased with age at all running levels, but the increase appeared to diminish by running further (0.259+-0.015 cm per year if running&lt;8 km/wk and 0.154+-0.003 cm per year for&gt;16 km/wk). In men over 50 years old, BMI declined -0.038+-0.001 kg/m2 per km/wk run when …
Date: June 1, 2004
Creator: Williams, Paul T. & Pate, Russell R.
Object Type: Article
System: The UNT Digital Library
The Department of State's Patterns of Global Terrorism Report: Trends, State Sponsors, and Related Issues (open access)

The Department of State's Patterns of Global Terrorism Report: Trends, State Sponsors, and Related Issues

This report highlights trends and data found in the State Department’s annual Patterns of Global Terrorism report, (Patterns 2003) and addresses selected issues relating to its content.
Date: June 1, 2004
Creator: Perl, Raphael F.
Object Type: Report
System: The UNT Digital Library
Department of Veterans Affairs: Federal Gulf War Illnesses Research Strategy Needs Reassessment (open access)

Department of Veterans Affairs: Federal Gulf War Illnesses Research Strategy Needs Reassessment

A letter report issued by the General Accounting Office with an abstract that begins "More than a decade after the 1991 Persian Gulf War, there is continued interest in the federal response to the health concerns of Gulf War veterans. Gulf War veterans' reports of unexplained illnesses and possible exposures to various health hazards have prompted numerous federal research projects on Gulf War illnesses. This research has been funded primarily by the Department of Veterans Affairs (VA), the Department of Defense (DOD), and the Department of Health and Human Services. GAO is reporting on (1) the status of research and investigations on Gulf War illnesses, (2) the efforts that have been made by VA and DOD to monitor cancer incidence among Gulf War veterans, and (3) VA's communication and collaboration with the Research Advisory Committee on Gulf War Veterans' Illnesses (RAC)."
Date: June 1, 2004
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library