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Regioselective Coupling Reactions of Diiodophenol Derivatives

Description: Palladium catalyzed reactions of derivatives of 2,4-diiodophenol are explored. Coupling reactions with a series of terminal alkynes and formylation are found to be efficient and regioselective. Coupling with stananne reagents and alkenes do not work. The nature of the oxygen protecting group is critical. The phytotoxic natural product, Eutypine, is synthesized by using regioselective formylation and alkyne coupling. An approach to the plant antimicrobial compound Plicatin B is examined.
Date: December 1994
Creator: Ji, Jianhua
Partner: UNT Libraries


Description: Project Objective: The overarching objective of the Montana Palladium Research Initiative is to perform scientific research on the properties and uses of palladium in the context of the U.S. Department of Energy'™s Hydrogen, Fuel Cells and Infrastructure Technologies Program. The purpose of the research will be to explore possible palladium as an alternative to platinum in hydrogen-economy applications. To achieve this objective, the Initiatives activities will focus on several cutting-edge research approaches across a range of disciplines, including metallurgy, biomimetics, instrumentation development, and systems analysis. Background: Platinum-group elements (PGEs) play significant roles in processing hydrogen, an element that shows high potential to address this need in the U.S. and the world for inexpensive, reliable, clean energy. Platinum, however, is a very expensive component of current and planned systems, so less-expensive alternatives that have similar physical properties are being sought. To this end, several tasks have been defined under the rubric of the Montana Palladium Research Iniative. This broad swath of activities will allow progress on several fronts. The membrane-related activities of Task 1 employs state-of-the-art and leading-edge technologies to develop new, ceramic-substrate metallic membranes for the production of high-purity hydrogen, and develop techniques for the production of thin, defect-free platinum group element catalytic membranes for energy production and pollution control. The biomimetic work in Task 2 explores the use of substrate-attached hydrogen-producing enzymes and the encapsulation of palladium in virion-based protein coats to determine their utility for distributed hydrogen production. Task 3 work involves developing laser-induced breakdown spectroscopy (LIBS) as a real-time, in situ diagnostic technique to characterize PGEs nanoparticles for process monitoring and control. The systems engineering work in task 4 will determine how fuel cells ”taken as systems behave over periods of time that should show how their reformers and other subsystems deteriorate with time.
Date: May 9, 2012
Creator: McCloskey, John; Douglas, Jay; Young, Trevor; Snyder, Mark; Gurney, Stuart & Peters, Brian
Partner: UNT Libraries Government Documents Department

Nuclear Reactions on the Palladium Isotopes

Description: The problem of interest in this investigation was to determine the cross sections of five nuclear reactions which occur when irradiating natural palladium with neutrons which have energy values of 15.1, 15.9, and 16.3 MeV. The cross sections were measured relative to a copper monitor which was "sandwitched" in with the palladium target.
Date: December 1970
Creator: White, Ronald Lee
Partner: UNT Libraries

Thermal Neutron Capture Cross Sections of the PalladiumIsotopes

Description: Precise gamma-ray thermal neutron capture cross sectionshave been measured at the Budapest Reactor for all elements withZ=1-83,92 except for He and Pm. These measurements and additional datafrom the literature been compiled to generate the Evaluated Gamma-rayActivation File (EGAF), which is disseminated by LBNL and the IAEA. Thesedata are nearly complete for most isotopes with Z<20 so the totalradiative thermal neutron capture cross sections can be determineddirectly from the decay scheme. For light isotopes agreement with therecommended values is generally satisfactory although large discrepanciesexist for 11B, 12,13C, 15N, 28,30Si, 34S, 37Cl, and 40,41K. Neutroncapture decay data for heavier isotopes are typically incomplete due tothe contribution of unresolved continuum transitions so only partialradiative thermal neutron capture cross sections can be determined. Thecontribution of the continuum to theneutron capture decay scheme arisesfrom a large number of unresolved levels and transitions and can becalculated by assuming that the fluctuations in level densities andtransition probabilities are statistical. We have calculated thecontinuum contribution to neutron capture decay for the palladiumisotopes with the Monte Carlo code DICEBOX. These calculations werenormalized to the experimental cross sections deexciting low excitationlevels to determine the total radiative thermal neutron capture crosssection. The resulting palladium cross sections values were determinedwith a precision comparable to the recommended values even when only onegamma-ray cross section was measured. The calculated and experimentallevel feedings could also be compared to determine spin and parityassignments for low-lying levels.
Date: July 17, 2006
Creator: Firestone, R.B.; Krticka, M.; McNabb, D.P.; Sleaford, B.; Agvaanluvsan, U.; Belgya, T. et al.
Partner: UNT Libraries Government Documents Department

Effect of Palladium Form on Tetraphenylborate Decomposition Rate

Description: Palladium catalyzes the decomposition of tetraphenylborate in alkaline solutions. Researchers postulate several decomposition mechanisms that differ in the form of the palladium catalyst. Potential forms include solid and soluble, different soluble species (such as aqueous or organic soluble), and different oxidation states (i.e., 0, II, and IV). Initial tests measured the reactivity and distribution of four Pd forms in tetraphenylborate slurries.
Date: April 28, 1998
Creator: Walker, D. D.
Partner: UNT Libraries Government Documents Department

Permeation and Diffusion of Hydrogen Through Pd Membranes

Description: Hydrogen diffusion through Pd membranes has been measured under non-UHV conditions, i.e., the membranes are evacuated under non-UHV conditions. Despite this, the results indicate that bulk diffusion is the slow step and the diffusion constants agree with earlier workers results where UHV conditions obtained. The activation energy for H2 permeation in the dilute phase was determined from an Arrhenius plot over a series of temperatures from 423 to 503 K. The solubilities of H2 were determined over the same temperature range and from these data, the diffusion constants were determined.
Date: January 29, 2003
Creator: Shanahan, K.L.
Partner: UNT Libraries Government Documents Department

Selective extraction of copper, mercury, silver and palladium ionsfrom water using hydrophobic ionic liquids.

Description: Extraction of dilute metal ions from water was performed near room temperature with a variety of ionic liquids. Distribution coefficients are reported for fourteen metal ions extracted with ionic liquids containing cations 1-octyl-4-methylpyridinium [4MOPYR]{sup +}, 1-methyl-1-octylpyrrolidinium [MOPYRRO]{sup +} or 1-methyl-1-octylpiperidinium [MOPIP]{sup +}, and anions tetrafluoroborate [BF{sub 4}]{sup +}, trifluoromethyl sulfonate [TfO]{sup +} or nonafluorobutyl sulfonate [NfO]{sup +}. Ionic liquids containing octylpyridinium cations are very good for extracting mercury ions. However, other metal ions were not significantly extracted by any of these ionic liquids. Extractions were also performed with four new task-specific ionic liquids. Such liquids containing a disulfide functional group are efficient and selective for mercury and copper, whereas those containing a nitrile functional group are efficient and selective for silver and palladium.
Date: June 25, 2007
Creator: Papaiconomou, Nicolas; Lee, Jong-Min; Salminen, Justin; VonStosch, Moritz & Prausnitz, John M.
Partner: UNT Libraries Government Documents Department

Reactivity of Metal Ions Bound to Water-Soluble Polymers

Description: The intent of this work is to determine the effectiveness of catalysts covalently bound to polymers and to understand the consequences of supporting the catalysts on catalyst efficiency and selectivity. Rhodium phosphine complexes with functional groups for coupling to polymers were prepared. These catalyst precursors were characterized using standard techniques including IR, NMR, and elemental analysis. Studies on the modified catalysts showed that they were still active hydrogenation catalysts. However, tethering of the catalysts to polyamines gave systems with low hydrogenation activity. Analogous biphasic systems were also explored. Phosphine ligands with a surfactant-like structure have been synthesized and used to prepare catalytically active complexes of palladium. The palladium complexes were utilized in Heck-type coupling reactions (e.g. coupling of iodobenzene and ethyl acrylate to produce ethyl cinnamate) under vigorously stirred biphasic reaction conditions, and were found to offer superior performance over a standard water-soluble palladium catalyst under analogous conditions.
Date: June 29, 1999
Creator: Sauer, N.N.; Watkins, J.G.; Lin, M.; Birnbaum, E.R.; Robison, T.W.; Smith, B.F. et al.
Partner: UNT Libraries Government Documents Department

Local Probe into the Atomic Structure of Metallic Glasses using EELS

Description: Electron energy loss spectroscopy (EELS) is used to extract information on the topological arrangement of atoms around Pd in the bulk-glass-forming Pd{sub 60}Ni{sub 20}P{sub 20}. It is found that the environment around Pd in the glass is only a slight modification of the Pd crystalline structure. However, the modification is enough to allow this alloy to form a glass in bulk. In examining the differences between the structure of crystalline Pd and glassy Pd{sub 60}Ni{sub 20}P{sub 20} it is concluded that incorporation of Ni and P into the structure frustrates the structure enough that glass formation becomes easy.
Date: November 30, 1999
Creator: Alamgir, F.M. & Ito, Y. Schwarz, R.B.
Partner: UNT Libraries Government Documents Department

The Near Elimination of Hysteresis in Pd/Cr2O3 Composites

Description: Although its value varies with the microstructure, hysteresis always accompanies hydride formation and decomposition in Pd(pure)-H, e.g., it is present even in nano-crystalline and thin films. Internal oxidation of Pd0.93Cr0.07 alloys leads to a pure Pd matrix containing nano-crystalline chromia precipitates. The characteristic hysteresis of Pd-H almost disappears in this form of Pd. The reasons for this are discussed. Hysteresis is an almost universal feature of first order solid state transitions. Its presence means that when such a transition is reversed, it follows a different path than that taken in the forward direction leading to a loss of useful work. Hysteresis is, of course, a reflection of the irreversibility of the transition.
Date: July 14, 2004
Partner: UNT Libraries Government Documents Department

Distributed Fiber Optic Gas Sensing for Harsh Environment

Description: This report summarizes work to develop a novel distributed fiber-optic micro-sensor that is capable of detecting common fossil fuel gases in harsh environments. During the 32-month research and development (R&amp;D) program, GE Global Research successfully synthesized sensing materials using two techniques: sol-gel based fiber surface coating and magnetron sputtering based fiber micro-sensor integration. Palladium nanocrystalline embedded silica matrix material (nc-Pd/Silica), nanocrystalline palladium oxides (nc-PdO{sub x}) and palladium alloy (nc-PdAuN{sub 1}), and nanocrystalline tungsten (nc-WO{sub x}) sensing materials were identified to have high sensitivity and selectivity to hydrogen; while the palladium doped and un-doped nanocrystalline tin oxide (nc-PdSnO{sub 2} and nc-SnO{sub 2}) materials were verified to have high sensitivity and selectivity to carbon monoxide. The fiber micro-sensor comprises an apodized long-period grating in a single-mode fiber, and the fiber grating cladding surface was functionalized by above sensing materials with a typical thickness ranging from a few tens of nanometers to a few hundred nanometers. GE found that the morphologies of such sensing nanomaterials are either nanoparticle film or nanoporous film with a typical size distribution from 5-10 nanometers. nc-PdO{sub x} and alloy sensing materials were found to be highly sensitive to hydrogen gas within the temperature range from ambient to 150 C, while nc-Pd/Silica and nc-WO{sub x} sensing materials were found to be suitable to be operated from 150 C to 500 C for hydrogen gas detection. The palladium doped and un-doped nc-SnO{sub 2} materials also demonstrated sensitivity to carbon monoxide gas at approximately 500 C. The prototyped fiber gas sensing system developed in this R&amp;D program is based on wavelength-division-multiplexing technology in which each fiber sensor is identified according to its transmission spectra features within the guiding mode and cladding modes. The interaction between the sensing material and fossil fuel gas results in a refractive index change and optical absorption ...
Date: March 14, 2008
Creator: Wu, Juntao
Partner: UNT Libraries Government Documents Department

Development of an inter-atomic potential for the Pd-H binary system.

Description: Ongoing research at Sandia National Laboratories has been in the area of developing models and simulation methods that can be used to uncover and illuminate the material defects created during He bubble growth in aging bulk metal tritides. Previous efforts have used molecular dynamics calculations to examine the physical mechanisms by which growing He bubbles in a Pd metal lattice create material defects. However, these efforts focused only on the growth of He bubbles in pure Pd and not on bubble growth in the material of interest, palladium tritide (PdT), or its non-radioactive isotope palladium hydride (PdH). The reason for this is that existing inter-atomic potentials do not adequately describe the thermodynamics of the Pd-H system, which includes a miscibility gap that leads to phase separation of the dilute (alpha) and concentrated (beta) alloys of H in Pd at room temperature. This document will report the results of research to either find or develop inter-atomic potentials for the Pd-H and Pd-T systems, including our efforts to use experimental data and density functional theory calculations to create an inter-atomic potential for this unique metal alloy system.
Date: September 1, 2007
Creator: Zimmerman, Jonathan A.; Hoyt, Jeffrey John (McMaster University, Hamilton, Ontario, Canada); Leonard, Francois Leonard; Griffin, Joshua D. & Zhou, Xiao Wang
Partner: UNT Libraries Government Documents Department

Effect of palladium dispersion on the capture of toxic components from fuel gas by palladium-alumina sorbents

Description: The dispersion and location of Pd in alumina-supported sorbents prepared by different methods was found to influence the performance of the sorbents in the removal of mercury, arsine, and hydrogen selenide from a simulated fuel gas. When Pd is well dispersed in the pores of the support, contact interaction with the support is maximized, Pd is less susceptible to poisoning by sulfur. and the sorbent has better long-term activity for adsorption of arsine and hydrogen selenide. but poorer adsorption capacity for Hg. As the contact interaction between Pd and the support is lessened the Pd becomes more susceptible to poisoning by sulfur. resulting in higher capacity for Hg, but poorer long-term performance for adsorption of arsenic and selenium.
Date: January 1, 2011
Creator: Baltrus, J.P.; Granite, E.J.; Rupp, E.C.; Stanko, D.C.; Howard, B. & Pennline, H.W.
Partner: UNT Libraries Government Documents Department

High-Performance Palladium Based Membrane for Hydrogen Separation and Purification

Description: The mission of the DOE's Fuel Cell Technologies'™Hydrogen Fuels R&D effort is to research, develop, and validate technologies for producing, storing, and delivering hydrogen in an efficient, clean, safe, reliable, and affordable manner. A key program technical milestone for hydrogen technology readiness is to produce hydrogen from diverse, domestic resources at $2.00-$3.00 per gallon of gasoline equivalent (gge) delivered, untaxed. Low-cost, high-temperature hydrogen separation membranes represent a key enabling technology for small-scale distributed hydrogen production units. Availability of such membranes with high selectivity and high permeability for hydrogen will allow their integration with hydrocarbon reforming and water gas shift reactions, potentially reducing the cost of hydrogen produced. Pd-metal-based dense membranes are known for their excellent hydrogen selectivity and permeability characteristics, however, utilization of these membranes has so far been limited to small scale niche markets for hydrogen purification primarily due to the relatively high cost of Pd-alloy tubes compared to pressure swing adsorption (PSA) units. This project was aimed at development of thin-film Pd-alloy membranes deposited on Pall Corporation's DOE-based AccuSep® porous metal tube substrates to form a composite hydrogen separation membrane for these applications. Pall's composite membrane development addressed the typical limitations of composite structures by developing robust membranes capable of withstanding thermal and mechanical stresses resulting from high temperature (400C), high pressure (400 psi steam methane reformer and 1000 psi coal) operations and thermal cycling involved in conventional hydrogen production. In addition, the Pd-alloy membrane composition was optimized to be able to offer the most stability in the typical synthesis gas environments produced by reforming of natural gas and bio-derived liquid fuels (BILI) validating the technical effectiveness and economic feasibility of the technology demonstrated. Results from this research added technology and product design information that offers the potential to significantly advance the commercial viability of hydrogen production.
Date: January 31, 2012
Creator: Hopkins, Scott
Partner: UNT Libraries Government Documents Department

High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances

Description: The project team consisting of Southwest Research Institute{reg_sign} (SwRI{reg_sign}), Georgia Institute of Technology (GT), the Colorado School of Mines (CSM), TDA Research, and IdaTech LLC was focused on developing a robust, poison-tolerant, hydrogen selective free standing membrane to produce clean hydrogen. The project completed on schedule and on budget with SwRI, GT, CSM, TDA and IdaTech all operating independently and concurrently. GT has developed a robust platform for performing extensive DFT calculations for H in bulk palladium (Pd), binary alloys, and ternary alloys of Pd. Binary alloys investigated included Pd96M4 where M = Li, Na, Mg, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. They have also performed a series of calculations on Pd{sub 70}Cu{sub 26}Ag{sub 4}, Pd{sub 70}Cu{sub 26}Au{sub 4}, Pd{sub 70}Cu{sub 26}Ni{sub 4}, Pd{sub 70}Cu{sub 26}Pt{sub 4}, and Pd{sub 70}Cu{sub 26}Y{sub 4}. SwRI deposited and released over 160 foils of binary and ternary Pd alloys. There was considerable work on characterizing and improving the durability of the deposited foils using new alloy compositions, post annealing and ion bombardment. The 10 and 25 {micro}m thick films were sent to CSM, TDA and IdaTech for characterization and permeation testing. CSM conducted over 60 pure gas permeation tests with SwRI binary and ternary alloy membranes. To date the PdAu and PdAuPt membranes have exhibited the best performance at temperatures in the range of 423-773 C and their performance correlates well with the predictions from GT. TDA completed testing under the Department of Energy (DOE) WGS conditions on over 16 membranes. Of particular interest are the PdAuPt alloys that exhibited only a 20% ...
Date: December 31, 2010
Creator: Coulter, K.
Partner: UNT Libraries Government Documents Department

Deep oxidation of methane on particles derived from YSZ-supported Pd-Pt-(O) coatings synthesized by pulsed filtered cathodic arc

Description: Methane conversion tests were performed on Pd, PdOy, Pd0.6Pt0.4Oy and Pd0.4Pt0.6Oy thin films deposited on yttria stabilized zirconia (YSZ) substrates. Pt containing films exhibited poor activity and high reducibility. As-deposited Pd and PdOy films showed good activity and transformed, during the cycling process, to particles dispersed on the YSZ substrates. The higher reaction rate of initially PdOy films was explained by a better dispersion of the catalyst. A drop of the reaction rate was observed when the temperature exceeded 735oC and 725oC for initially Pd and PdOy, respectively, which can be associated with the high-temperature reduction of PdO into Pd.
Date: December 12, 2008
Creator: Horwat, D.; Endrino, J.L.; Boreave, A.; Karoum,R.; Pierson, J.F.; Weber, S. et al.
Partner: UNT Libraries Government Documents Department

Effect of H2S on performance of Pd4Pt alloy membranes

Description: The effect of H2S on the performance of a hydrogen separation membrane with the composition Pd4Pt was evaluated at 350, 400 and 450°C. Exposure to hydrogen containing 1000 ppm H2S and 10%He resulted in two performance trends. At 350°C, a continuous decline in flux was observed which was attributed to the growth of sulphide corrosion on the membrane surface linked to surface contamination by stainless steel derived particles. At 400 and 450°C, the H2 flux decreased sharply followed by a slow recovery. This trend was attributed to Pt enrichment of the surface resulting from extraction of Pd through the formation of Pd4Pt. Also at 400 and 450°C, stainless steel based particle contamination was found to modify and/or enhance the corrosive effects of the H2S containing test gas. The implications of the metallic and/or metal sulphide surface contaminant effects are significant in that these contaminants could result in severe performance degradation and ultimately even mechanical failure.
Date: January 1, 2008
Creator: Howard, B.H. & Morreale, B.D.
Partner: UNT Libraries Government Documents Department

The Interaction of Dissolved H with Internally Oxidized Pd-Rh Alloys

Description: Binary Pd-M alloys containing small amounts of readily oxidizable solute metals such as M equals Al, Mg, or Zr, can be internally oxidized to form essentially pure Pd matrices containing a second phase of nano-sized oxide precipitates. During internal oxidation Pd atoms are transported to the surface forming Pd nodules while vacancies are transported from the surface to the metal/oxide interface relieving the compressive stress which develops within the alloy due to the expanding metal oxide precipitates. The Pd alloys that have been studied contain that form very stable oxides.
Date: April 20, 2001
Creator: Shanahan, K.L.
Partner: UNT Libraries Government Documents Department

SRS history and experience with palladium diffusers. Revision 1

Description: The Savannah River Site (SRS) has processed tritium in support of national defense programs since 1955. Palladium diffusers have been used extensively for separating hydrogen isotopes from inert gases (such as argon, helium, and nitrogen). In almost forty years of service, the design of the diffuser has been steadily improving. Several diffuser designs from different manufacturers have been evaluated at SRS. The operating experience gained from these designs together with failure analyses performed on failed units have led to several recommendations for improved diffuser designs and operating methods. This experience gained at SRS and the following recommendations form the basis of this report. Even though palladium diffuser technology has proven to be reliable, SRS has examined several alternative technologies over the past several years. This report will also review some of these promising alternatives.
Date: August 11, 1995
Creator: Clark, E.A.; Dauchess, D.A.; Heung, L.K.; Rabun, R.L. & Motyka, T.
Partner: UNT Libraries Government Documents Department


Description: Over the last quarter, we developed procedures for producing free-standing, defect free films using rigid silicon and glass substrates over areas up to 12 square inches. Since formation of contiguous Pd-Cu films in the 2-3 {micro}m-thick range is ultimately governed by the size of the particle contamination on the supporting substrate surface, we have adopted techniques utilized by the semiconductor industry to reduce and eventually eliminate particle contamination. We have found these techniques to be much more effective on rigid substrates and have made a down select decision on removal methods (a key milestone) based on these results and the performance of membranes fabricated by this technique. The path to fabricating even larger membranes is straightforward and will be demonstrated in the coming months. Hydrogen permeation tests were also conducted this quarter on as-deposited, Pd-Cu membranes, between 6-14 {micro}m-thick. In the case of a 6 {micro}m-thick film, the pure hydrogen flux at 20 psig and {approx}260 C was 36 cm{sup 3}(STP)/cm{sup 2} min. This flux corresponds to a pure hydrogen permeability of 7.4 {center_dot} 10{sup -5} cm{sup 3} cm cm{sup -2} s{sup -1} cm Hg{sup -1/2} at 250 C. This value is within 20% of the pure hydrogen permeability at 250 C reported in the McKinley patent. In the case of a 14 {micro}m-thick membrane tested at 350 C, the pure hydrogen flux, measured before initiating a pinhole-size leak, was 2.1 {center_dot} 10{sup -5} cm{sup 3}(STP) {center_dot} cm/cm{sup 2} {center_dot} s {center_dot} cm Hg{sup 0.5}. This value is considerably lower than the expected permeability of Pd{sub 60}Cu{sub 40} materials at 400 C. To date, essentially all of the sputtered deposited Pd-Cu thin film membranes have had palladium compositions that were as much as 3% greater than the ideal 60 weight percent composition (this is a direct consequence of sputtering from ...
Date: January 28, 2005
Creator: Lanning, B. & Arps, J.
Partner: UNT Libraries Government Documents Department

Comment on ''Thermal Behavior of Polarized Pd/D Electrodes Prepared by Co-Deposition''

Description: This paper presents the basics of this model, including what physical conditions could produce a calibration constant shift and what might cause those conditions to arise. The new evidences are discussed and it is shown that the possibility of at-the-electrode recombination cannot be eliminated, in fact prior photographic evidence is shown to be reasonable evidence of this phenomenon. Thus in the absence of definitive data, the conclusion that apparent excess heat arises from a nuclear cause is premature. If the apparent excess heat signal is not representative of a true heat source, but is instead an equipment/method malfunction, integrating the signal is of no value. This paper proposes that is the situation, and will therefore focus on examining the phenomenon of apparent excess enthalpy (sometimes called excess heat). Not addressed will be the myriad of other purported evidences of nuclear reactions. The apparent excess heat claims form the largest block of claims for a nuclear FPHE cause, and the correlation of apparent excess heat with apparent nuclear ash detection is often cited as evidence of the nuclear nature of the FPHE. But confidence in the validity of the apparent excess heat signal is of critical importance in validating a nuclear explanation. If the heat signal is erroneous, any correlation to nuclear ash production must also be erroneous, and the nuclear ash measurements likely spurious. This is a critical realization.
Date: July 14, 2004
Partner: UNT Libraries Government Documents Department