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LONG-TERM PERFORMANCE OF SOLID OXIDE STACKS WITH ELECTRODE-SUPPORTED CELLS OPERATING IN THE STEAM ELECTROLYSIS MODE (open access)

LONG-TERM PERFORMANCE OF SOLID OXIDE STACKS WITH ELECTRODE-SUPPORTED CELLS OPERATING IN THE STEAM ELECTROLYSIS MODE

Performance characterization and durability testing have been completed on two five-cell high-temperature electrolysis stacks constructed with advanced cell and stack technologies. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. The per-cell active area is 100 cm2. The stack is internally manifolded with compliant mica-glass seals. Treated metallic interconnects with integral flow channels separate the cells. Stack compression is accomplished by means of a custom spring-loaded test fixture. Initial stack performance characterization was determined through a series of DC potential sweeps in both fuel cell and electrolysis modes of operation. Results of these sweeps indicated very good initial performance, with area-specific resistance values less than 0.5 ?.cm2. Long-term durability testing was performed with A test duration of 1000 hours. Overall performance degradation was less than 10% over the 1000-hour period. Final stack performance characterization was again determined by a series of DC potential sweeps at the same flow conditions as the initial sweeps in both electrolysis and fuel cell modes of operation. A final sweep in the fuel cell mode indicated a power density of 0.356 W/cm2, with average per-cell voltage of 0.71 V at …
Date: November 1, 2011
Creator: O'Brien, J. E.; O'Brien, R. C.; Zhang, X.; Tao, G. & Butler, B. J.
System: The UNT Digital Library
A Fisheye Lens for Many Point PDV (open access)

A Fisheye Lens for Many Point PDV

The features of the fisheye lens are illustrated, including a design with reflector prisms. The fisheye fiber map and the beam footprint are shown. Fisheye rough-angle metrology was done and results presented. Next steps are given, including a smaller top fisheye lens element, longer reflector prisms with better mounting, and different fiber arrangements.
Date: November 1, 2011
Creator: Frogget, B.
System: The UNT Digital Library
Transverse modes and instabilities of a bunched beam with space charge and resistive wall impedance (open access)

Transverse modes and instabilities of a bunched beam with space charge and resistive wall impedance

Transverse instability of a bunch in a ring accelerator is considered with space charge and wakefield taken into account. It is assumed that space charge tune shift significantly exceeds the synchrotron tune. Bunch spectrum, instability growth rate, and effects of chromaticity are studied with different bunch and wake forms. Fast instability caused by coupling of transverse modes is studied in detail. It is shown that, for monotonic wakes, the transverse mode coupling instability is possible only with a certain sign of the wake. Its threshold and growth rate are calculated precisely over a wide range of parameters.
Date: November 1, 2011
Creator: Balbekov, V.
System: The UNT Digital Library
Processing Tons of Data with QuickView (open access)

Processing Tons of Data with QuickView

This presentation describes the QuickView software used to process data
Date: November 1, 2011
Creator: Diaz, A. B.
System: The UNT Digital Library
Preliminary results from the MINERvA experiment (open access)

Preliminary results from the MINERvA experiment

The MINERvA experiment, operating since 2009 in the NuMI neutrino beam line at Fermilab, has collected neutrino and antineutrino scattering data on a variety of nuclear targets. The detector is designed to identify events originating in plastic scintillator, lead, carbon, iron, water, and liquid helium. The goal of the experiment is to measure inclusive and exclusive cross sections for neutrino and antineutrino with much greater precision than previous experiments. We present preliminary kinematic distributions for charged current quasi-elastic scattering and other processes.
Date: November 1, 2011
Creator: Harris, Deborah A.
System: The UNT Digital Library
NUMERICAL SIMULATION FOR MECHANICAL BEHAVIOR OF U10MO MONOLITHIC MINIPLATES FOR RESEARCH AND TEST REACTORS (open access)

NUMERICAL SIMULATION FOR MECHANICAL BEHAVIOR OF U10MO MONOLITHIC MINIPLATES FOR RESEARCH AND TEST REACTORS

This article presents assessment of the mechanical behavior of U-10wt% Mo (U10Mo) alloy based monolithic fuel plates subject to irradiation. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Identification of the stress/strain characteristics is important for understanding the in-reactor performance of these plate-type fuels. For this work, three distinct cases were considered: (1) fabrication induced residual stresses (2) thermal cycling of fabricated plates; and finally (3) transient mechanical behavior under actual operating conditions. Because the temperatures approach the melting temperature of the cladding during the fabrication and thermal cycling, high temperature material properties were incorporated to improve the accuracy. Once residual stress fields due to fabrication process were identified, solution was used as initial state for the subsequent simulations. For thermal cycling simulation, elasto-plastic material model with thermal creep was constructed and residual stresses caused by the fabrication process were included. For in-service simulation, coupled fluid-thermal-structural interaction was considered. First, temperature field on the plates was calculated and this field was used to compute the thermal stresses. For time dependent mechanical behavior, thermal …
Date: November 1, 2011
Creator: Shen, Hakan Ozaltun & Herman
System: The UNT Digital Library
Byers Auto Group: A Case Study Into The Economics, Zoning, and Overall Process of Installing Small Wind Turbines at Two Automotive Dealerships in Ohio (open access)

Byers Auto Group: A Case Study Into The Economics, Zoning, and Overall Process of Installing Small Wind Turbines at Two Automotive Dealerships in Ohio

This paper provides the talking points about a case study on the installation of a $600,000 small wind project, the installation process, estimated annual energy production and percentage of energy needs met by the turbines.
Date: November 1, 2011
Creator: Oteri, F. & Sinclair, K.
System: The UNT Digital Library
Measurements of the top quark mass and decay width with the D0 detector (open access)

Measurements of the top quark mass and decay width with the D0 detector

The top quark discovery in 1995 at Fermilab is one of the major proofs of the standard model (SM). Due to its unique place in SM, the top quark is an important particle for testing the theory and probing for new physics. This article presents most recent measurements of top quark properties from the D0 detector. In particular, the measurement of the top quark mass, the top antitop mass difference and the top quark decay width. The discovery of the top quark in 1995 confirmed the existence of a third generation of quarks predicted in the standard model (SM). Being the heaviest elementary particle known, the top quark appears to become an important particle in our understanding of the standard model and physics beyond it. Because of its large mass the top quark has a very short lifetime, much shorter than the hadronization time. The predicted lifetime is only 3.3 {center_dot} 10{sup -25}s. Top quark is the only quark whose properties can be studied in isolation. A Lorentz-invariant local Quantum Field Theory, the standard model is expected to conserve CP. Due to its unique properties, the top quark provides a perfect test of CPT invariance in the standard model. An …
Date: November 1, 2011
Creator: Ilchenko, Yuriy
System: The UNT Digital Library
Further developments in generating type-safe messaging (open access)

Further developments in generating type-safe messaging

At ICALEPCS 09, we introduced a source code generator that allows processes to communicate safely using data types native to each host language. In this paper, we discuss further development that has occurred since the conference in Kobe, Japan, including the addition of three more client languages, an optimization in network packet size and the addition of a new protocol data type. The protocol compiler is continuing to prove itself as an easy and robust way to get applications written in different languages hosted on different computer architectures to communicate. We have two active Erlang projects that are using the protocol compiler to access ACNET data at high data rates. We also used the protocol compiler output to deliver ACNET data to an iPhone/iPad application. Since it takes an average of two weeks to support a new language, we're willing to expand the protocol compiler to support new languages that our community uses.
Date: November 1, 2011
Creator: Neswold, R. & King, C.
System: The UNT Digital Library
Semileptonic Form Factor ratio B_s->D_s/B->D and Its Application to BR(B^0_s->\mu^+\mu^-) (open access)

Semileptonic Form Factor ratio B_s->D_s/B->D and Its Application to BR(B^0_s->\mu^+\mu^-)

We present a (2+1)-flavor lattice QCD calculation of the form factor ratio between the semileptonic decays {bar B}{sub s}{sup 0} {yields} D{sub s}{sup +}l{sup -}{bar {nu}} and {bar B}{sup 0} {yields} D{sup +}l{sup -}{bar {nu}}. This ratio is an important theoretical input to the hadronic determination of the B meson fragmentation fraction ratio f{sub s}/f{sub d} which enters in the measurement of BR(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -}). Small lattice spacings and high statistics enable us to simulate the decays with a dynamic final D meson of small momentum and reliably extract the hadronic matrix elements at nonzero recoil. We report our preliminary result for the form factor ratio at the corresponding momentum transfer of the two decays f{sub 0}{sup (s)} (M{sub {pi}}{sup 2})/f{sub 0}{sup (d)} (M{sub K}{sup 2}).
Date: November 1, 2011
Creator: Du, Daping; DeTar, Carleton; Kronfeld, Andreas; Laiho, Jack; Meurice, Yannick & Qiu, Si-wei
System: The UNT Digital Library
Search for the Standard Model Higgs boson in final states with $b$ quarks at the Tevatron (open access)

Search for the Standard Model Higgs boson in final states with $b$ quarks at the Tevatron

We present the result of searches for a low mass Standard Model Higgs boson produced in association with a W or a Z boson at a center-of-mass energy of {radical}s = 1.96 TeV with the CDF and D0 detectors at the Fermilab Tevatron collider. The search is performed in events containing one or two b tagged jets in association with either two leptons, or one lepton and an imbalance in transverse energy, or simply a large imbalance in transverse energy. Datasets corresponding to up to 8.5 fb{sup -1} of integrated luminosity are considered in the analyses. These are the most powerful channels in the search for a low mass Higgs boson at the Tevatron. Recent sensitivity improvements are discussed. For a Higgs mass of 115 GeV/c{sup 2}, the expected sensitivity for the most sensitive individual analyses reaches 2.3 times the SM prediction at 95% confidence level (C.L.), with all limits below 5 times the SM. Additionally, a WZ/ZZ cross-section measurement is performed to validate the analysis techniques deployed for searching for the Higgs.
Date: November 1, 2011
Creator: Potamianos, Karolos
System: The UNT Digital Library
A novel digitization scheme with FPGA-base TDC for beam loss monitors operating at cryogenic temperature (open access)

A novel digitization scheme with FPGA-base TDC for beam loss monitors operating at cryogenic temperature

Recycling integrators are common current-to-frequency converting circuits for measurements of low current such as that produced by Fermilab's cryogenic ionization chambers. In typical digitization/readout schemes, a counter is utilized to accumulate the number of pulses generated by the recycling integrator to adequately digitize the total charge. In order to calculate current with reasonable resolution (e.g., 7-8 bits), hundreds of pulses must be accumulated which corresponds to a long sampling period, i.e., a very low sampling rate. In our new scheme, an FPGA-based Time-to-Digital Convertor (TDC) is utilized to measure the time intervals between the pulses output from the recycling integrator. Using this method, a sample point of the current can be made with good resolution (>10 bits) for each pulse. This effectively increases the sampling rates by hundreds of times for the same recycling integrator front-end electronics. This scheme provides a fast response to the beams loss and is potentially suitable for accelerator protection applications. Moreover, the method is also self-zero-suppressed, i.e., it produces more data when the beam loss is high while it produces significantly less data when the beam loss is low.
Date: November 1, 2011
Creator: Wu, Jinyuan & Warner, Arden
System: The UNT Digital Library
Constants and Pseudo-Constants of Coupled Beam Motion in the PEP-II Rings (open access)

Constants and Pseudo-Constants of Coupled Beam Motion in the PEP-II Rings

Constants of beam motion help as cross checks to analyze beam diagnostics and the modeling procedure. Pseudo-constants, like the betatron mismatch parameter or the coupling parameter det C, are constant till certain elements in the beam line change them. This can be used to visually find the non-desired changes, pinpointing errors compared with the model.
Date: November 1, 2011
Creator: Decker, F. J.; Colocho, W. S.; Wang, M. H.; Yan, Y. T. & Yocky, G.
System: The UNT Digital Library
The Lederman Science Center: Past, Present, Future (open access)

The Lederman Science Center: Past, Present, Future

For 30 years, Fermilab has offered K-12 education programs, building bridges between the Lab and the community. The Lederman Science Center is our home. We host field trips and tours, visit schools, offer classes and professional development workshops, host special events, support internships and have a strong web presence. We develop programs based on identified needs, offer programs with peer-leaders and improve programs from participant feedback. For some we create interest; for others we build understanding and develop relationships, engaging participants in scientific exploration. We explain how we created the Center, its programs, and what the future holds.
Date: November 1, 2011
Creator: Bardeen, Marjorie G.
System: The UNT Digital Library
ACYSYS in a box (open access)

ACYSYS in a box

The Accelerator Control System at Fermilab has evolved to enable this relatively large control system to be encapsulated into a 'box' such as a laptop. The goal was to provide a platform isolated from the 'online' control system. This platform can be used internally for making major upgrades and modifications without impacting operations. It also provides a standalone environment for research and development including a turnkey control system for collaborators. Over time, the code base running on Scientific Linux has enabled all the salient features of the Fermilab's control system to be captured in an off-the-shelf laptop. The anticipated additional benefits of packaging the system include improved maintenance, reliability, documentation, and future enhancements.
Date: November 1, 2011
Creator: Briegel, C.; Finstrom, D.; Hendricks, B.; King, C.; Lackey, S.; Neswold, R. et al.
System: The UNT Digital Library
Updated Search for $B_s \to \mu^+$ mu- at CDF (open access)

Updated Search for $B_s \to \mu^+$ mu- at CDF

The decay B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} is very sensitive to contributions from new physics processes. Thus the Tevatron and LHC experiments are hunting for an observation of a B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} signal. In this article the updated search for B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup -} and B{sup 0} {yields} {mu}{sup +}{mu}{sup -} by the CDF experiment is presented. The CDF result was received with great interest because an excess over the background expectation is seen, although of modest statistical significance and still consistent with the prediction of a standard model signal and other experimental results.
Date: November 1, 2011
Creator: Kuhr, Thomas & /Karlsruhe, Inst. Technol. /Karlsruhe U., EKP
System: The UNT Digital Library
THE MATHEMATICAL ANALYSIS OF A NOVEL APPROACH TO MAXIMIZE WASTE RECOVERY IN A LIFE SUPPORT SYSTEM (open access)

THE MATHEMATICAL ANALYSIS OF A NOVEL APPROACH TO MAXIMIZE WASTE RECOVERY IN A LIFE SUPPORT SYSTEM

NASA has been evaluating closed-loop atmosphere revitalization architectures that include carbon dioxide (CO2) reduction technologies. The CO2 and steam (H2O) co-electrolysis process is one of the reduction options that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide (CO) and hydrogen (H2) mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. Two process models were developed to evaluate novel approaches for energy storage and resource recovery in a life support system. In the first model, products from the INL co-electrolysis process are combined to produce methanol fuel. In the second co-electrolysis, products are separated with a pressure swing adsorption (PSA) process. In both models the fuels are burned with added oxygen to produce H2O and CO2, the original reactants. For both processes, the overall power increases as the syngas ratio, H2/CO, increases because more water is needed to produce more hydrogen at a set CO2 incoming flow rate. The power for the methanol cases is less than pressure swing adsorption, …
Date: November 1, 2011
Creator: McKellar, Michael G.; Wood, Rick A.; Stoots, Carl M.; Mulloth, Lila & Luna, Bernadette
System: The UNT Digital Library
Application of Vacuum Salt Distillation Technology for the Removal of Fluoride and Chloride from Legacy Fissile Materials (open access)

Application of Vacuum Salt Distillation Technology for the Removal of Fluoride and Chloride from Legacy Fissile Materials

Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and the Savannah River Site (SRS) HB-Line Facility designed, developed, tested, and successfully deployed a production-scale system for the distillation of sodium chloride (NaCl) and potassium chloride (KCl) from plutonium oxide (PuO{sub 2}). Subsequent efforts adapted the vacuum salt distillation (VSD) technology for the removal of chloride and fluoride from less-volatile halide salts at the same process temperature and vacuum. Calcium chloride (CaCl{sub 2}), calcium fluoride (CaF{sub 2}), and plutonium fluoride (PuF{sub 3}) were of particular concern. To enable the use of the same operating conditions for the distillation process, SRNL employed in situ exchange reactions to convert the less-volatile halide salts to compounds that facilitated the distillation of halide without removal of plutonium. SRNL demonstrated the removal of halide from CaCl{sub 2}, CaF{sub 2} and PuF{sub 3} below 1000 C using VSD technology.
Date: November 1, 2011
Creator: Pierce, R. & Caldwell, T.
System: The UNT Digital Library
Measurement of CP--violating asymmetries in $D^0\to\pi^+\pi^-$ and $D^0\to K^+K^-$ decays at CDF (open access)

Measurement of CP--violating asymmetries in $D^0\to\pi^+\pi^-$ and $D^0\to K^+K^-$ decays at CDF

We report on a measurement of CP-violating asymmetries (A{sub CP}) in the Cabibbo-suppressed D{sup 0} {yields} {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} K{sup +}K{sup -} decays reconstructed in a data sample corresponding to 5.9 fb{sup -1} of integrated luminosity collected by the upgraded Collider Detector at Fermilab. We use the strong decay D*{sup +} {yields} D{sup 0}{pi}{sup +} to identify the flavor of the charmed meson at production and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. High-statistics samples of Cabibbo-favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without a D*{sup {+-}} tag are used to correct for instrumental effects and significantly reduce systematic uncertainties. We measure A{sub CP}(D{sup 0} {yields} {pi}{sup +}{pi}{sup -}) = (+0.22 {+-} 0.24(stat) {+-} 0.11 (syst))% and A{sub CP}(D{sup 0} {yields} K{sup +}K{sup -}) = (-0.24 {+-} 0.22 (stat) {+-} 0.09 (syst))%, in agreement with CP conservation. These are the most precise determinations from a single experiment to date. Under the assumption of negligible direct CP violation in D{sup 0} {yields} {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} K{sup +}K{sup -} decays, the results provide an upper limit to the CP-violating asymmetry in D{sup 0} mixing, |A{sub CP}{sup ind}(D{sup 0})| …
Date: November 1, 2011
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
System: The UNT Digital Library
Benchmarking of Graphite Reflected Critical Assemblies of UO2 (open access)

Benchmarking of Graphite Reflected Critical Assemblies of UO2

A series of experiments were carried out in 1963 at the Oak Ridge National Laboratory Critical Experiments Facility (ORCEF) for use in space reactor research programs. A core containing 93.2% enriched UO2 fuel rods was used in these experiments. The first part of the experimental series consisted of 253 tightly-packed fuel rods (1.27 cm triangular pitch) with graphite reflectors [1], the second part used 253 graphite-reflected fuel rods organized in a 1.506 cm triangular pitch [2], and the final part of the experimental series consisted of 253 beryllium-reflected fuel rods with a 1.506 cm triangular pitch. [3] Fission rate distribution and cadmium ratio measurements were taken for all three parts of the experimental series. Reactivity coefficient measurements were taken for various materials placed in the beryllium reflected core. The first part of this experimental series has been evaluated for inclusion in the International Reactor Physics Experiment Evaluation Project (IRPhEP) [4] and the International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbooks, [5] and is discussed below. These experiments are of interest as benchmarks because they support the validation of compact reactor designs with similar characteristics to the design parameters for a space nuclear fission surface power systems. [6]
Date: November 1, 2011
Creator: Marshall, Margaret A. & Bess, John D.
System: The UNT Digital Library
Performance Assessment of Single Electrode-Supported Solid Oxide Cells Operating in the Steam Electrolysis Mode (open access)

Performance Assessment of Single Electrode-Supported Solid Oxide Cells Operating in the Steam Electrolysis Mode

An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. Results presented in this paper were obtained from single cells, with an active area of 16 cm{sup 2} per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes ({approx}10 {mu}m thick), nickel-YSZ steam/hydrogen electrodes ({approx}1400 {mu}m thick), and modified LSM or LSCF air-side electrodes ({approx}90 {mu}m thick). The purpose of the present study is to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of voltage-current (VI) sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-term testing, first in the fuel cell mode, then in the electrolysis mode. Results generally indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of an improved single-cell test apparatus developed specifically for these experiments.
Date: November 1, 2011
Creator: Zhang, X.; O'Brien, J. E.; O'Brien, R. C. & Petigny, N.
System: The UNT Digital Library
Integrating Nuclear Energy to Oilfield Operations – Two Case Studies (open access)

Integrating Nuclear Energy to Oilfield Operations – Two Case Studies

Fossil fuel resources that require large energy inputs for extraction, such as the Canadian oil sands and the Green River oil shale resource in the western USA, could benefit from the use of nuclear power instead of power generated by natural gas combustion. This paper discusses the technical and economic aspects of integrating nuclear energy with oil sands operations and the development of oil shale resources. A high temperature gas reactor (HTGR) that produces heat in the form of high pressure steam (no electricity production) was selected as the nuclear power source for both fossil fuel resources. Both cases were based on 50,000 bbl/day output. The oil sands case was a steam-assisted, gravity-drainage (SAGD) operation located in the Canadian oil sands belt. The oil shale development was an in-situ oil shale retorting operation located in western Colorado, USA. The technical feasibility of the integrating nuclear power was assessed. The economic feasibility of each case was evaluated using a discounted cash flow, rate of return analysis. Integrating an HTGR to both the SAGD oil sands operation and the oil shale development was found to be technically feasible for both cases. In the oil sands case, integrating an HTGR eliminated natural gas …
Date: November 1, 2011
Creator: Robertson, Eric P.; Nelson, Lee O.; McKellar, Michael G.; Gandrik, Anastasia M. & Patterson, Mike W.
System: The UNT Digital Library
Spark Plasma Sintering of Fuel Cermets for Nuclear Reactor Applications (open access)

Spark Plasma Sintering of Fuel Cermets for Nuclear Reactor Applications

The feasibility of the fabrication of tungsten based nuclear fuel cermets via Spark Plasma Sintering (SPS) is investigated in this work. CeO2 is used to simulate fuel loadings of UO2 or Mixed-Oxide (MOX) fuels within tungsten-based cermets due to the similar properties of these materials. This study shows that after a short time sintering, greater than 90 % density can be achieved, which is suitable to possess good strength as well as the ability to contain fission products. The mechanical properties and the densities of the samples are also investigated as functions of the applied pressures during the sintering.
Date: November 1, 2011
Creator: Zhong, Yang; O'Brien, Robert C.; Howe, Steven D.; Jerred, Nathan D.; Schwinn, Kristopher; Sudderth, Laura et al.
System: The UNT Digital Library
Western Red-tailed Skink Distribution in Southern Nevada (open access)

Western Red-tailed Skink Distribution in Southern Nevada

This slide show reports a study to: determine Western Red-tailed Skink (WRTS) distribution on Nevada National Security Site (NNSS); identify habitat where WRTS occur; learn more about WRTS natural history; and document distribution of other species.
Date: November 1, 2011
Creator: Hall, D. B. and Gergor, P. D.
System: The UNT Digital Library