14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti (open access)

14C/C measurements support Andreev's internode method to determine lichen growth rates in Cladina stygia (Fr.) Ahti

Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of {sup 14}C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using {sup 14}C/C ratios was 6.5 mm {center_dot} yr{sup -1}, which was not significantly different from growth rates derived by Andreev's internode method (average = 6.2 mm {center_dot} yr{sup -1}); thus, suggesting the reliability of Andreev's simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.
Date: December 5, 2007
Creator: Holt, E. & Bench, G.
Object Type: Article
System: The UNT Digital Library
1995 NPTS Databook (open access)

1995 NPTS Databook

Policymakers rely on transportation statistics, including data on personal travel behavior, to formulate strategic transportation policies and to improve the safety and efficiency of the U.S. transportation system. Data on personal travel trends are needed to examine the reliability, efficiency, capacity, and flexibility of the Nation's transportation system to meet current demands and accommodate future demands; to assess the feasibility and efficiency of alternative congestion-alleviating technologies (e.g., high-speed rail, magnetically levitated trains, intelligent vehicle and highway systems); to evaluate the merits of alternative transportation investment programs; and to assess the energy-use and air-quality impacts of various policies. To address these data needs, the Department of Transportation (DOT) initiated an effort in 1969 to collect detailed data on personal travel. The 1969 survey was the first Nationwide Personal Transportation Survey (NPTS). The survey was conducted again in 1977, 1983, 1990, and 1995. The 1995 survey was cosponsored by four DOT agencies: Federal Highway Administration (FHWA), Bureau of Transportation Statistics (BTS), Federal Transit Administration (FTA), and National Highway Traffic Safety Administration (NHTSA). The primary objective of the survey was to collect trip-based data on the nature and characteristics of personal travel. Commercial and institutional travel were not part of the survey.
Date: December 5, 2001
Creator: Hu, P. S.
Object Type: Report
System: The UNT Digital Library
Accelerator physics and technology limitations to ultimate energy and luminosity in very large hadron colliders (open access)

Accelerator physics and technology limitations to ultimate energy and luminosity in very large hadron colliders

The following presents a study of the accelerator physics and technology limitations to ultimate energy and luminosity in very large hadron colliders (VLHCs). The main accelerator physics limitations to ultimate energy and luminosity in future energy frontier hadron colliders are synchrotron radiation (SR) power, proton-collision debris power in the interaction regions (IR), number of events-per-crossing, stored energy per beam and beam-stability [1]. Quantitative estimates of these limits were made and translated into scaling laws that could be inscribed into the particle energy versus machine size plane to delimit the boundaries for possible VLHCs. Eventually, accelerator simulations were performed to obtain the maximum achievable luminosities within these boundaries. Although this study aimed at investigating a general VLHC, it was unavoidable to refer in some instances to the recently studied, [2], 200 TeV center-of-mass energy VLHC stage-2 design (VLHC-2). A more thorough rendering of this work can be found in [3].
Date: December 5, 2002
Creator: al., P. Bauer et
Object Type: Article
System: The UNT Digital Library
Acceptance Test Procedure for New Pumping Instrumentation and Control Skid U (open access)

Acceptance Test Procedure for New Pumping Instrumentation and Control Skid U

This Acceptance Test Procedure (ATP) provides for the inspection and testing of the new Pumping Instrumentation and Control (PIC) skid designed as ''U''. The ATP will be performed after the construction of the PIC skid in the fabrication shop.
Date: December 5, 2000
Creator: Koch, M. R.
Object Type: Report
System: The UNT Digital Library
Actinide Spectroscopy Workshop (open access)

Actinide Spectroscopy Workshop

Actinide materials present an extreme scientific challenge to the materials research community. The complex electronic structures of actinide materials result in many unusual and unique properties that have yet to be fully understood. The difficulties in handling, preparing, and characterizing actinide materials has frequently precluded investigations and has the limited the detailed understanding of these relevant, complex materials. However, modern experiments with actinide materials have the potential to provide key, fundamental information about many long-standing issues concerning actinide materials. This workshop focused on the scientific and technical challenges posed by actinide materials and the potential that synchrotron radiation approaches available at the ALS can contribute to improving the fundamental understanding of actinides materials. Fundamental experimental approaches and results, as well as theoretical modeling and computational simulations, were part of the workshop program.
Date: December 5, 2004
Creator: Tobin, J.G. & Shuh, D.K.
Object Type: Article
System: The UNT Digital Library
Aerodynamic levitation : an approach to microgravity. (open access)

Aerodynamic levitation : an approach to microgravity.

Measurements of the thermophysical and structural properties of liquid materials at high temperature have undergone considerable development in the past few years. Following improvements in electromagnetic levitation, aerodynamic levitation associated with laser heating has shown promise for assessing properties of different molten materials (metals, oxides, and semiconductors), preserving sample purity over a wide range of temperatures and under different gas environments. The density, surface tension and viscosity are measured with a high-speed video camera and an image analysis system. Results on nickel and alumina show that small droplets can be considered in the first approximation to be under microgravity conditions. Using a non-invasive contactless technique recently developed to measure electrical conductivity, results have been extended to variety of materials ranging from liquid metals and liquid semiconductors to ionically conducting materials. The advantage of this technique is the feasibility of monitoring changes in transport occurring during phase transitions and in deeply undercooled states.
Date: December 5, 2000
Creator: Glorieux, B.; Saboungi, M.-L.; Millot, F.; Enderby, J. & Rifflet, J.-C.
Object Type: Article
System: The UNT Digital Library
ALS user meeting features 10th anniversary celebration (open access)

ALS user meeting features 10th anniversary celebration

The Advanced Light Source (ALS) saw first light on October 5, 1993, not quite to the day but close to 10 years before the 2003 ALS Users Association meeting, held October 6-8. Fittingly, the proceedings included retrospectives from two of the key players in the early history of the ALS, David Attwood and Jay Marx, and a display of photographs chronicling its construction and commissioning. Science highlights, highlights from young researchers, and posters constituted the meat of the program on Monday and Tuesday morning, while workshops took over Tuesday afternoon and all day Wednesday.
Date: December 5, 2003
Creator: Robinson, Art
Object Type: Article
System: The UNT Digital Library
Analysis of Rayleigh-Taylor Instability: Statistics on Rising Bubbles and Falling Spikes (open access)

Analysis of Rayleigh-Taylor Instability: Statistics on Rising Bubbles and Falling Spikes

None
Date: December 5, 2007
Creator: Kamath, C; Gezahegne, A & Miller, P
Object Type: Report
System: The UNT Digital Library
Analysis of the Effects of Compositional and Configurational Assumptions on Product Costs for the Thermochemical Conversion of Lignocellulosic Biomass to Mixed Alcohols -- FY 2007 Progress Report (open access)

Analysis of the Effects of Compositional and Configurational Assumptions on Product Costs for the Thermochemical Conversion of Lignocellulosic Biomass to Mixed Alcohols -- FY 2007 Progress Report

The purpose of this study was to examine alternative biomass-to-ethanol conversion process assumptions and configuration options to determine their relative effects on overall process economics. A process-flow-sheet computer model was used to determine the heat and material balance for each configuration that was studied. The heat and material balance was then fed to a costing spreadsheet to determine the impact on the ethanol selling price. By examining a number of operational and configuration alternatives and comparing the results to the base flow sheet, alternatives having the greatest impact the performance and cost of the overall system were identified and used to make decisions on research priorities.
Date: December 5, 2008
Creator: Zhu, Yunhua; Gerber, Mark A.; Jones, Susanne B. & Stevens, Don J.
Object Type: Report
System: The UNT Digital Library
Annotating user-defined abstractions for optimization (open access)

Annotating user-defined abstractions for optimization

This paper discusses the features of an annotation language that we believe to be essential for optimizing user-defined abstractions. These features should capture semantics of function, data, and object-oriented abstractions, express abstraction equivalence (e.g., a class represents an array abstraction), and permit extension of traditional compiler optimizations to user-defined abstractions. Our future work will include developing a comprehensive annotation language for describing the semantics of general object-oriented abstractions, as well as automatically verifying and inferring the annotated semantics.
Date: December 5, 2005
Creator: Quinlan, D; Schordan, M; Vuduc, R & Yi, Q
Object Type: Article
System: The UNT Digital Library
Anthropogenically-Induced Climate Change: Final Report (open access)

Anthropogenically-Induced Climate Change: Final Report

Paper number 1 addresses the fact that the procedure used in the Earth Radiation Budget Experiment for identifying the presence of clouds over snow/ice surfaces is known to have shortcomings, and this is corroborated through use of surface insolation measurements at the South Pole as an independent means of identifying clouds. These surface insolation measurements are then used to validate the more detailed cloud identification scheme used in the follow-up Clouds and the Earth's Radiant Energy System (CERES), and this validation is extended to the polar night through use of CERES measurements of the outgoing longwave radiation. General circulation models (GCMs) are highly sophisticated computer tools for modeling climate change, and they incorporate a large number of physical processes and variables. One of the most important challenges is to properly account for water vapor (clouds and humidity) in climate warming. In this Perspective, Cess discusses results reported in the same issue by Soden et al. in which water vapor feedback effects are tested by studying moistening trends in the upper troposphere. Satellite observations of atmospheric water vapor are found to agree well with moisture predictions generated by one of the key GCMs, showing that these feedback effects are being properly …
Date: December 5, 2008
Creator: Cess, Robert D.
Object Type: Report
System: The UNT Digital Library
Aperture studies for the AP2 anti-proton Line at Fermilab (open access)

Aperture studies for the AP2 anti-proton Line at Fermilab

The AP2 beamline transports anti-protons from the production target to the Debuncher ring. For many years the observed aperture has been smaller than that estimated from linear, on-energy optics. We have investigated possible reasons for the aperture restriction and have identified several possible sources, including residual vertical dispersion from alignment errors and chromatic effects due to very large chromatic lattice functions. We discuss the possible sources, suggest some remedies, and propose specific studies, where needed, to evaluate suspected problems.
Date: December 5, 2003
Creator: Reichel, Ina; Zisman, Michael & Placidi, Massimo
Object Type: Report
System: The UNT Digital Library
Application of the PSUADE tool for Sensitivity Analysis of an Engineering Simulation (open access)

Application of the PSUADE tool for Sensitivity Analysis of an Engineering Simulation

None
Date: December 5, 2007
Creator: Hsieh, H
Object Type: Report
System: The UNT Digital Library
Assessment of Unabated Facility Emission Potentials for Evaluating Airborne Radionuclide Monitoring Requirements at Pacific Northwest National Laboratory - 2003 (open access)

Assessment of Unabated Facility Emission Potentials for Evaluating Airborne Radionuclide Monitoring Requirements at Pacific Northwest National Laboratory - 2003

Assessments were performed to evaluate compliance with the airborne radionuclide emission monitoring requirements in the National Emission Standards for Hazardous Air Pollutants (NESHAP - U.S. Code of Federal Regulations, Title 40, Part 61, Subpart H) and Washington Administrative Code (WAC) 246-247: Radiation Protection - Air Emissions. In these assessments, potential unabated offsite doses were evaluated for emission locations at facilities owned by the U.S. Department of Energy and operated by Pacific Northwest National Laboratory (PNNL) on the Hanford Site. This report describes the inventory-based methods and provides the results for the assessment performed in 2003.
Date: December 5, 2003
Creator: Ballinger, Marcel Y.; Sula, Monte J.; Gervais, Todd L. & Edwards, Daniel L.
Object Type: Report
System: The UNT Digital Library
Avian Survey and Field Guide for Osan Air Base, Korea. (open access)

Avian Survey and Field Guide for Osan Air Base, Korea.

This report summarizes the results of the avian surveys conducted at Osan Air Base (AB). This ongoing survey is conducted to comply with requirements of the Environmental Governing Standards (EGS) for the Republic of Korea, the Integrated Natural Resources Management Plan (INRMP) for Osan AB, and the 51st Fighter Wing's Bird Aircraft Strike Hazard (BASH) Plan. One hundred ten bird species representing 35 families were identified and recorded. Seven species are designated as Natural Monuments, and their protection is accorded by the Korean Ministry of Culture and Tourism. Three species appear on the Korean Association for Conservation of Nature's (KACN's) list of Reserved Wild Species and are protected by the Korean Ministry of Environment. Combined, ten different species are Republic of Korea (ROK)-protected. The primary objective of the avian survey at Osan AB was to determine what species of birds are present on the airfield and their respective habitat requirements during the critical seasons of the year. This requirement is specified in Annex J.14.c of the 51st Fighter BASH Plan 91-212 (51 FW OPLAN 91-212). The second objective was to initiate surveys to determine what bird species are present on Osan AB throughout the year and from the survey results, …
Date: December 5, 2006
Creator: Levenson, J.
Object Type: Report
System: The UNT Digital Library
Business Development Executive (BDE) Program (open access)

Business Development Executive (BDE) Program

The IPST BDE (Institute of Paper Science and Technology Business Development Executive) program was initiated in 1997 to make the paper industry better aware of the new manufacturing technologies being developed at IPST for the U.S. pulp and paper industry's use. In April 2000, the BDE program management and the 20 BDEs, all retired senior level industry manufacturing and research executives, were asked by Ms. Denise Swink of OIT at DOE to take the added responsibility of bringing DOE developed energy conservation technology to the paper industry. This project was funded by a DOE grant of $950,000.
Date: December 5, 2005
Creator: Rice, E.J. "Woody" & Frederick, W. James
Object Type: Report
System: The UNT Digital Library
CALIBRATION OF ONLINE ANALYZERS USING NEURAL NETWORKS (open access)

CALIBRATION OF ONLINE ANALYZERS USING NEURAL NETWORKS

Neural networks were used to calibrate an online ash analyzer at the Usibelli Coal Mine, Healy, Alaska, by relating the Americium and Cesium counts to the ash content. A total of 104 samples were collected from the mine, with 47 being from screened coal, and the rest being from unscreened coal. Each sample corresponded to 20 seconds of coal on the running conveyor belt. Neural network modeling used the quick stop training procedure. Therefore, the samples were split into training, calibration and prediction subsets. Special techniques, using genetic algorithms, were developed to representatively split the sample into the three subsets. Two separate approaches were tried. In one approach, the screened and unscreened coal was modeled separately. In another, a single model was developed for the entire dataset. No advantage was seen from modeling the two subsets separately. The neural network method performed very well on average but not individually, i.e. though each prediction was unreliable, the average of a few predictions was close to the true average. Thus, the method demonstrated that the analyzers were accurate at 2-3 minutes intervals (average of 6-9 samples), but not at 20 seconds (each prediction).
Date: December 5, 2003
Creator: Ganguli, Rajive; Walsh, Daniel E. & Yu, Shaohai
Object Type: Report
System: The UNT Digital Library
Cesium-137 in the Sediments of Fourmile Creek (open access)

Cesium-137 in the Sediments of Fourmile Creek

The Nonproliferation Technology Section (NTS) was requested by the Environmental Restoration Division (ER) to aid in completing ground-truth measurements of aerial overflight data in support of the Integrator Operable Unit (IOU) program at the Savannah River Site (SRS). The IOU's at the SRS are under investigation as a possible pathway for the release of contamination from past SRS activities to off-unit receptors and the environment. The IOU's are defined as surface water bodies and associated wetlands, including the water, sediment and related biota. The objective of the IOU program is to: assess the risk to potential human and ecological receptors from IOU contamination; evaluate the impact of inactive and active waste units and operating facilities on the IOU quality; determine if IOU early actions, including reprioritization of operable units implementation schedules, are necessary; and complete the remedial investigation/feasibility study process, defining the nature and extent of IOU contamination, remedial action objectives, and final remediation goals.
Date: December 5, 2002
Creator: Beals, D.M.
Object Type: Report
System: The UNT Digital Library
COMPARISON OF RESPONSE OF 9977 TEST PACKAGES TO ANALYTICAL RESULTS (open access)

COMPARISON OF RESPONSE OF 9977 TEST PACKAGES TO ANALYTICAL RESULTS

Each of the hypothetical accident test cases for the 9977 prototypes was included in the battery of finite element structural analyses performed for the package. Comparison of the experimental and analytical results provides a means of confirming that the analytical model correctly represents the physical behavior of the package. The ability of the analytical model to correctly predict the performance of the foam overpack material for the crush test is of particular interest. The dissipation of energy in the crushing process determines the deceleration of the package upon impact and the duration of the impact. In addition, if the analytical model correctly models the foam behavior, the predicted deformation of the package will match that measured on the test articles. This study compares the deformations of the test packages with the analytical predictions. In addition, the impact acceleration and impact duration for the test articles are compared with those predicted by the analyses.
Date: December 5, 2007
Creator: Smith, A & Tsu-Te Wu, T
Object Type: Article
System: The UNT Digital Library
Compressible Multiphase Flows in an ALE Framework (open access)

Compressible Multiphase Flows in an ALE Framework

None
Date: December 5, 2003
Creator: Stevens, David; Nelson, B.; Fogarty, P.; Eberle, C. & Ulrickson, M.
Object Type: Article
System: The UNT Digital Library
Continuum description of avalanches in granular media. (open access)

Continuum description of avalanches in granular media.

A continuum theory of partially fluidized granular flows is proposed. The theory is based on a combination of the mass and momentum conservation equations with the order parameter equation which describes the transition between flowing and static components of the granular system. We apply this model to the dynamics of avalanches in chutes. The theory provides a quantitative description of recent observations of granular flows on rough inclined planes (Daerr and Douady 1999): layer bistability, and the transition from triangular avalanches propagating downhill at small inclination angles to balloon-shaped avalanches also propagating uphill for larger angles.
Date: December 5, 2000
Creator: Aranson, I. S. & Tsimring, L. S.
Object Type: Article
System: The UNT Digital Library
A cosmic perspective from Lapland in 2001 (open access)

A cosmic perspective from Lapland in 2001

A convergence of ideas, observations and technology have led to the greatest period of cosmological discovery yet. Over the past three years we have determined the basic features of our Universe. We are now challenged to make sense of what we have found. The outcome of planned experiments and observations as well as new ideas will be required. If we succeed, ours truly will be a Golden Age of Cosmology.
Date: December 5, 2002
Creator: Turner, Michael s.
Object Type: Article
System: The UNT Digital Library
Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons (open access)

Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons

The reactions of the methylidyne radical (CH) with ethylene, acetylene, allene, and methylacetylene are studied at room temperature using tunable vacuum ultraviolet (VUV) photoionization and time-resolved mass spectrometry. The CH radicals are prepared by 248 nm multiphoton photolysis of CHBr3 at 298 K and react with the selected hydrocarbon in a helium gas flow. Analysis of photoionization efficiency versus VUV photon wavelength permits isomer-specific detection of the reaction products and allows estimation of the reaction product branching ratios. The reactions proceed by either CH insertion or addition followed by H atom elimination from the intermediate adduct. In the CH + C2H4 reaction the C3H5 intermediate decays by H atom loss to yield 70(+-8)percent allene, 30(+-8)percent methylacetylene and less than 10percent cyclopropene, in agreement with previous RRKM results. In the CH + acetylene reaction, detection of mainly the cyclic C3H2 isomer is contrary to a previous RRKM calculation that predicted linear triplet propargylene to be 90percent of the total H-atom co-products. High-level CBS-APNO quantum calculations and RRKM calculation for the CH + C2H2 reaction presented in this manuscript predict a higher contribution of the cyclic C3H2 (27.0percent) versus triplet propargylene (63.5percent) than these earlier predictions. Extensive calculations on the C3H3 and …
Date: December 5, 2008
Creator: Goulay, Fabien; Trevitt, Adam J.; Meloni, Giovanni; Selby, Talitha M.; Osborn, David L.; Taatjes, Craig A. et al.
Object Type: Article
System: The UNT Digital Library
Damping Investigations of a Simplified Frictional Shear Joint (open access)

Damping Investigations of a Simplified Frictional Shear Joint

None
Date: December 5, 2000
Creator: Smallwood, D.O.; Gregory, D.L. & Coleman, R.G.
Object Type: Article
System: The UNT Digital Library