An analysis of model tropospheric response to various forcings (open access)

An analysis of model tropospheric response to various forcings

None
Date: January 30, 2006
Creator: Hnilo, J J & Christy, J R
System: The UNT Digital Library
Plasma"anti-assistance" and"self-assistance" to high power impulse magnetron sputtering (open access)

Plasma"anti-assistance" and"self-assistance" to high power impulse magnetron sputtering

A plasma assistance system was investigated with the goal to operate high power impulse magnetron sputtering (HiPIMS) at lower pressure than usual, thereby to enhance the utilization of the ballistic atoms and ions with high kinetic energy in the film growth process. Gas plasma flow from a constricted plasma source was aimed at the magnetron target. Contrary to initial expectations, such plasma assistance turned out to be contra-productive because it led to the extinction of the magnetron discharge. The effect can be explained by gas rarefaction. A better method of reducing the necessary gas pressure is operation at relatively high pulse repetition rates where the afterglow plasma of one pulse assists in the development of the next pulse. Here we show that this method, known from medium-frequency (MF) pulsed sputtering, is also very important at the much lower pulse repetition rates of HiPIMS. A minimum in the possible operational pressure is found in the frequency region between HiPIMS and MF pulsed sputtering.
Date: January 30, 2009
Creator: Anders, Andre & Yushkov, Georgy Yu.
System: The UNT Digital Library
A cell nanoinjector based on carbon nanotubes (open access)

A cell nanoinjector based on carbon nanotubes

Technologies for introducing molecules into living cells are vital for probing the physical properties and biochemical interactions that govern the cell's behavior. Here we report the development of a nanoscale cell injection system-termed the nanoinjector-that uses carbon nanotubes to deliver cargo into cells. A single multi-walled carbon nanotube attached to an atomic force microscope tip was functionalized with cargo via a disulfide-based linker. Penetration of cell membranes with this 'nanoneedle', followed by reductive cleavage of the disulfide bonds within the cell's interior, resulted in the release of cargo inside the cells. The capability of the nanoinjector was demonstrated by injection of protein-coated quantum dots into live human cells. Single-particle tracking was employed to characterize the diffusion dynamics of injected quantum dots in the cytosol. This new technique causes no discernible membrane or cell damage, and can deliver a discrete number of molecules to the cell's interior without the requirement of a carrier solvent.
Date: January 30, 2007
Creator: Chen, Xing; Kis, Andras; Zettl, Alex & Bertozzi, Carolyn R.
System: The UNT Digital Library
Vortex Characterization for Engineering Applications (open access)

Vortex Characterization for Engineering Applications

Realistic engineering simulation data often have features that are not optimally resolved due to practical limitations on mesh resolution. To be useful to application engineers, vortex characterization techniques must be sufficiently robust to handle realistic data with complex vortex topologies. In this paper, we present enhancements to the vortex topology identification component of an existing vortex characterization algorithm. The modified techniques are demonstrated by application to three realistic data sets that illustrate the strengths and weaknesses of our approach.
Date: January 30, 2008
Creator: Jankun-Kelly, M; Thompson, D S; Jiang, M; Shannahan, B & Machiraju, R
System: The UNT Digital Library
Is there a low energy enhancement in the photon strength function in molybdenum? (open access)

Is there a low energy enhancement in the photon strength function in molybdenum?

Recent claims of a low energy enhancement in the photon strength function of {sup 96}Mo are investigated. Using the DANCE detector the gamma-ray spectra following resonance neutron capture was measured. The spectrum fitting method was used to indirectly extract a photon strength function from the gamma-ray spectra. No strong low energy enhancement in the photon strength function was found.
Date: January 30, 2008
Creator: Sheets, S A
System: The UNT Digital Library
Visible Light Absorption of Binuclear TiOCoII Charge-Transfer UnitAssembled in Mesoporous Silica (open access)

Visible Light Absorption of Binuclear TiOCoII Charge-Transfer UnitAssembled in Mesoporous Silica

Grafting of CoII(NCCH3)2Cl2 onto mesoporous Ti-MCM-41 silicain acetonitrile solution affords binuclear Ti-O-CoII sites on the poresurface under complete replacement of the precursor ligands byinteractions with anchored Ti centers and the silica surface. The CoIIligand field spectrum signals that the Co centers are anchored on thepore surface in tetrahedral coordination. FT-infrared action spectroscopyusing ammonia gas adsorption reveals Co-O-Si bond modes at 831 and 762cm-1. No Co oxide clusters are observed in the as-synthesized material.The bimetallic moieties feature an absorption extending from the UV intothe visible to about 600 nm which is attributed to the TiIV-O-CoII?3TiIII-O-CoIII metal-to-metal charge-transfer (MMCT) transition. Thechromophore is absent in MCM-41 containing Ti and Co centers isolatedfrom each other; this material was synthesized by grafting CoII onto aTi-MCM-41 sample with the Ti centers protected by a cyclopentadienylligand. The result indicates that the appearance of the charge-transferabsorption requires that the metal centers are linked by an oxo bridge,which is additionally supported by XANES spectroscopy. The MMCTchromophore of Ti-O-CoII units has sufficient oxidation power to serve asvisible light electron pump for driving multi-electron transfer catalystsof demanding uphill reactions such as water oxidation.
Date: January 30, 2007
Creator: Han, Hongxian & Frei, Heinz
System: The UNT Digital Library
Synthesis of a Benzodiazepine-derived Rhodium NHC Complex by C-H Bond Activation (open access)

Synthesis of a Benzodiazepine-derived Rhodium NHC Complex by C-H Bond Activation

The synthesis and characterization of a Rh(I)-NHC complex generated by C-H activation of 1,4-benzodiazepine heterocycle are reported. This complex constitutes a rare example of a carbene tautomer of a 1,4-benzodiazepine aldimine stabilized by transition metal coordination and demonstrates the ability of the catalytically relevant RhCl(PCy{sub 3}){sub 2} fragment to induce NHC-forming tautomerization of heterocycles possessing a single carbene-stabilizing heteroatom. Implications for the synthesis of benzodiazepines and related pharmacophores via C-H functionalization are discussed.
Date: January 30, 2008
Creator: Bergman, Roberg G.; Gribble, Jr., Michael W. & Ellman, Jonathan A.
System: The UNT Digital Library
Searches for the Decays B0 to l+- tau-+ and B+ to l+ nu(L=e,mu) using Hadronic Tag Reconstruction (open access)

Searches for the Decays B0 to l+- tau-+ and B+ to l+ nu(L=e,mu) using Hadronic Tag Reconstruction

We present searches for the leptonic decays B{sup +} {yields} {ell}{sup +}{nu} and the lepton flavor violating decays B{sup 0} {yields} {ell}{sup {+-}}{tau}{sup {-+}}, where {ell} = e, {mu}, with data collected by the BABAR experiment at SLAC. This search demonstrates a novel technique in which we fully reconstruct the accompanying {bar B} in {Upsilon}(4S) {yields} B{bar B} events, and look for a monoenergetic lepton from the signal B decay. The signal yield is extracted from a fit to the signal lepton candidate momentum distribution in the signal B rest frame. Using a data sample of approximately 378 million B{bar B} pairs (342 fb{sup -1}), we find no evidence of signal in any of the decay modes. Branching fraction upper limits of {Beta}(B{sup +} {yields} e{sup +}{nu}) < 5.2 x 10{sup -6}, {Beta}(B{sup +} {yields} {mu}{sup +}{nu}) < 5.6 x 10{sup -6}, {Beta}(B{sup 0} {yields} e{sup +}{tau}{sup -}) < 2.8 x 10{sup -5} and {Beta}(B{sup 0} {yields} {mu}{sup +}{tau}{sup -}) < 2.2 x 10{sup -5}, are obtained at 90% confidence level.
Date: January 30, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prudent, X. et al.
System: The UNT Digital Library
The Standard Chemical-Thermodynamic Properties of Phosphorus and Some of its Key Compounds and Aqueous Species: An Evaluation of Differences between the Previous Recommendations of NBS/NIST and CODATA (open access)

The Standard Chemical-Thermodynamic Properties of Phosphorus and Some of its Key Compounds and Aqueous Species: An Evaluation of Differences between the Previous Recommendations of NBS/NIST and CODATA

The aqueous chemistry of phosphorus is dominated by P(V), which under typical environmental conditions (and depending on pH and concentration) can be present as the orthophosphate ions H{sub 3}PO{sub 4}{sup 0}(aq), H{sub 2}PO{sub 4}{sup -}(aq), HPO{sub 4}{sup 2-}(aq), or PO{sub 4}{sup 3-}(aq). Many divalent, trivalent, and tetravalent metal ions form sparingly soluble orthophosphate phases that, depending on the solution pH and concentrations of phosphate and metal ions, can be solubility limiting phases. Geochemical and chemical engineering modeling of solubilities and speciation requires comprehensive thermodynamic databases that include the standard thermodynamic properties for the aqueous species and solid compounds. The most widely used sources for standard thermodynamic properties are the NBS (now NIST) Tables (from 1982 and earlier; with a 1989 erratum) and the final CODATA evaluation (1989). However, a comparison of the reported enthalpies of formation and Gibbs energies of formation for key phosphate compounds and aqueous species, especially H{sub 2}PO{sub 4}{sup -}(aq) and HPO{sub 4}{sup 2-}(aq), shows a systematic and nearly constant difference of 6.3 to 6.9 kJ {center_dot} mol{sup -1} per phosphorus atom between these two evaluations. The existing literature contains numerous studies (including major data summaries) that are based on one or the other of these evaluations. …
Date: January 30, 2007
Creator: Rard, J A & Wolery, T J
System: The UNT Digital Library
Active RF Pulse Compression using Electrically Controlled Semiconductor Switches (open access)

Active RF Pulse Compression using Electrically Controlled Semiconductor Switches

In this paper, we will present our recent results on the research of the ultra-fast high power RF switches based on silicon. We have developed a switch module at X-band which can use a silicon window as the switch. The switching is realized by generation of carriers in the bulk silicon. The carriers can be generated electrically or/and optically. The electrically controlled switches use PIN diodes to inject carrier. We have built the PIN diode switches at X-band, with <300ns switching time. The optically controlled switches use powerful lasers to excite carriers. By combining the laser excitation and electrical carrier generation, significant reduction in the required power of both the laser and the electrical driver is expected. High power test is under going.
Date: January 30, 2008
Creator: Guo, J. & Tantawi, S. G.
System: The UNT Digital Library
How did matter gain the upper hand over antimatter? (open access)

How did matter gain the upper hand over antimatter?

Antimatter exists! We routinely make it in laboratories. For every familiar particle type we find a matching antiparticle with opposite charge, but exactly the same mass. For example, a positron with positive charge has the same mass as an electron; an antiproton with negative charge has the same mass as a proton. Antimatter occurs naturally all over the universe wherever high-energy particles collide. The laws of physics for antimatter are very, very similar to those for antimatter--so far we know only one tiny difference in them, a detail of the weak interactions of quarks that earned Makoto Kobayashi and Toshihide Maskawa a share of the 2008 Nobel Prize for Physics. Our understanding of the early Universe also tells us that after inflation ended equal amounts of matter and antimatter were produced. Today there's a lot of matter in the universe, but very little antimatter. This leaves a big question for cosmology. How did matter gain the upper hand over antimatter? It's a question at the root of our existence. Without this excess, there would be no stars, no Earth, and no us! When a particle meets its antiparticle, they annihilate each other in a flash of radiation. This process removed …
Date: January 30, 2009
Creator: Quinn, Helen
System: The UNT Digital Library
Quality Assurance Source Requirements Traceability Database (open access)

Quality Assurance Source Requirements Traceability Database

At the Yucca Mountain Project the Project Requirements Processing System assists in the management of relationships between regulatory and national/industry standards source criteria, and Quality Assurance Requirements and Description document (DOE/R W-0333P) requirements to create compliance matrices representing respective relationships. The matrices are submitted to the U.S. Nuclear Regulatory Commission to assist in the commission's review, interpretation, and concurrence with the Yucca Mountain Project QA program document. The tool is highly customized to meet the needs of the Office of Civilian Radioactive Waste Management Office of Quality Assurance.
Date: January 30, 2006
Creator: MURTHY, R., NAYDENOVA, A., DEKLEVER, R., BOONE, A.
System: The UNT Digital Library
Fabrication and Characterization of Nanolayer Capacitors (open access)

Fabrication and Characterization of Nanolayer Capacitors

None
Date: January 30, 2008
Creator: Chow, R & Ellis, A D
System: The UNT Digital Library
Spin Dependent Electron Transmission Through Ferromagnetic Thin Films (open access)

Spin Dependent Electron Transmission Through Ferromagnetic Thin Films

None
Date: January 30, 2007
Creator: Komesu, T; Waddill, G D & Tobin, J G
System: The UNT Digital Library
The Rosetta Resources CO2 Storage Project - A WESTCARB Geologic Pilot Test (open access)

The Rosetta Resources CO2 Storage Project - A WESTCARB Geologic Pilot Test

WESTCARB, one of seven U.S. Department of Energypartnerships, identified (during its Phase I study) over 600 gigatonnesof CO2 storage capacity in geologic formations located in the Westernregion. The Western region includes the WESTCARB partnership states ofAlaska, Arizona, California, Nevada, Oregon and Washington and theCanadian province of British Columbia. The WESTCARB Phase II study iscurrently under way, featuring three geologic and two terrestrial CO2pilot projects designed to test promising sequestration technologies atsites broadly representative of the region's largest potential carbonsinks. This paper focuses on two of the geologic pilot studies plannedfor Phase II -referred to-collectively as the Rosetta-Calpine CO2 StorageProject. The first pilot test will demonstrate injection of CO2 into asaline formation beneath a depleted gas reservoir. The second test willgather data for assessing CO2 enhanced gas recovery (EGR) as well asstorage in a depleted gas reservoir. The benefit of enhanced oil recovery(EOR) using injected CO2 to drive or sweep oil from the reservoir towarda production well is well known. EaR involves a similar CO2 injectionprocess, but has received far less attention. Depleted natural gasreservoirs still contain methane; therefore, CO2 injection may enhancemethane production by reservoir repressurization or pressure maintenance.CO2 injection into a saline formation, followed by injection into adepleted natural …
Date: January 30, 2006
Creator: Trautz, Robert; Benson, Sally; Myer, Larry; Oldenburg, Curtis; Seeman, Ed; Hadsell, Eric et al.
System: The UNT Digital Library
Design and implementation of an emergency environmental responsesystem to protect migrating salmon in the lower San Joaquin River,California (open access)

Design and implementation of an emergency environmental responsesystem to protect migrating salmon in the lower San Joaquin River,California

In the past decade tens of millions of dollars have beenspent by water resource agencies in California to restore the nativesalmon fishery in the San Joaquin River and its major tributaries. Anexcavated deep water ship channel (DWSC), through which the river runs onits way to the Bay/Delta and Pacific Ocean, experiences episodes of lowdissolved oxygen which acts as a barrier to anadromous fish migration anda threat to the long-term survival of the salmon run. An emergencyresponse management system is under development to forecast theseepisodes of low dissolved oxygen and to deploy measures that will raisedissolved oxygen concentrations to prevent damage to the fisheryresource. The emergency response management system has been designed tointeract with a real-time water quality monitoring network and is servedby a comprehensive data management and forecasting model toolbox. TheBay/Delta and Tributaries (BDAT) Cooperative Data Management System is adistributed, web accessible database that contains terabytes ofinformation on all aspects of the ecology of the Bay/Delta and upperwatersheds. The complexity of the problem dictates data integration froma variety of monitoring programs. A unique data templating system hasbeen constructed to serve the needs of cooperating scientists who wish toshare their data and to simplify and streamline data uploading into themaster database. …
Date: January 30, 2006
Creator: Quinn, Nigel W.T. & Jacobs, Karl C.
System: The UNT Digital Library
Target plane imager for inertial confinement fusion (open access)

Target plane imager for inertial confinement fusion

The Nova laser, completed in December 1984 at Lawrence Livermore National Laboratory, is being used to conduct inertial confinement fusion experiments. It is capable of focusing more than 100 kJ of energy on small fusion targets. This paper discusses an optical system called the target plane imager that is used during the beam alignment phase of these experiments. The TPI includes a three meter long periscope with a wide field of view, F/3 objective. The telescope relays images of the target focal plane to viewing optics and a video sensor located outside the target chamber. Operation of the system is possible at three wavelengths: 1.05..mu.., 0.527..mu.., and 0.351..mu... These are the three wavelengths at which the ten Nova laser beams can irradiate targets. Both nearfield and farfield images of the ten beams can be viewed with the TPI. This instrument is used to properly align the laser to the target before each target irradiation.
Date: January 30, 1985
Creator: Swift, C. D.; Bliss, E. S.; Jones, W. A. & Seppala, L. G.
System: The UNT Digital Library
Solid state track detectors in the inertial confinement fusion program at LLL. [CR-39 and cellulose nitrate detectors] (open access)

Solid state track detectors in the inertial confinement fusion program at LLL. [CR-39 and cellulose nitrate detectors]

Two recent conference papers on the use of cellulose nitrate and CR-39 to diagnose laser fusion targets are combined with a chronological introduction and update to efforts in this area.
Date: January 30, 1980
Creator: Ceglio, N. M. & Benton, E. V.
System: The UNT Digital Library
Public participation at Fernald: FERMCO`s evolving role (open access)

Public participation at Fernald: FERMCO`s evolving role

In an effort to improve public involvement in the site restoration decision making process, the DOE has established site specific advisory boards, of which the Fernald Citizens Task Force is one. The Fernald Task Force is focused on making recommendations in four areas: (1) What should be the future use of the site? (2) Determinations of cleanup levels (how clean is clean?) (3) Where should the wastes be disposed of? (4) What should be the cleanup priorities? Because these questions are being asked very early in the decision-making process, the answers are necessarily qualified, and are based on a combination of preliminary data, assumptions, and professional judgment. The requirement to make progress in the absence of accurate data has necessitated FERMCO and the Task Force to employ an approach similar to sensitivity analysis, in which a range of possible data values are evaluated and the relative importance of the various factors is assessed. Because of its charter to provide recommendations of future site use, the Task Force has developed a sitewide perspective, compared to the more common operable unit specific focus of public participation under CERCLA. The relationship between FERMCO and the Task Force is evolving toward one of partnership …
Date: January 30, 1995
Creator: Williams, J. B.; Fellman, R. W. & Brettschneider, D. J.
System: The UNT Digital Library
Fernald waste management and disposition (open access)

Fernald waste management and disposition

Historically waste management within the Department of Energy complex has evolved around the operating principle of packaging waste generated and storing until a later date. In many cases wastes were delivered to onsite waste management organizations with little or no traceability to origin of generation. Sites then stored their waste for later disposition offsite or onsite burial. While the wastes were stored, sites incurred additional labor costs for maintaining, inspecting and repackaging containers and capital costs for storage warehouses. Increased costs, combined with the inherent safety hazards associated with storage of hazardous material make these practices less attractive. This paper will describe the methods used at the Department of Energy`s Fernald site by the Waste Programs Management Division to integrate with other site divisions to plan in situ waste characterization prior to removal. This information was utilized to evaluate and select disposal options and then to package and ship removed wastes without storage.
Date: January 30, 1995
Creator: West, M. L.; Fisher, L. A.; Frost, M. L. & Rast, D. M.
System: The UNT Digital Library
Progress in Horizontal and Slant-Path Imaging Speckle Imaging (open access)

Progress in Horizontal and Slant-Path Imaging Speckle Imaging

The difficulty in terrestrial imaging over long horizontal or slant paths is that atmospheric aberrations and distortions reduce the resolution and contrast in images recorded at high resolution. This paper will describe the problem of horizontal-path imaging, briefly cover various methods for imaging over horizontal paths and then describe the speckle imaging method actively being pursued at LLNL. We will review some closer range (1-3 km range) imagery of people we have already published, as well as show new results of vehicles we have obtained over longer slant-range paths greater than 20 km.
Date: January 30, 2003
Creator: Carrano, C J
System: The UNT Digital Library
A geomechanical mechanism that counteracts flow channeling induced by reservoir thermal drawdown (open access)

A geomechanical mechanism that counteracts flow channeling induced by reservoir thermal drawdown

None
Date: January 30, 2013
Creator: Fu, P; Hao, Y & Carrigan, C R
System: The UNT Digital Library
Quantum Raman spectroscopy. II. Isotope ratio measurements in oxygen and nitrogen (open access)

Quantum Raman spectroscopy. II. Isotope ratio measurements in oxygen and nitrogen

Measurements of the /sup 14/N/sup 15/N//sup 14/N/sup 14/N and /sup 16/O/sup 18/O//sup 16/O/sup 16/O Raman intensity ratios have been made in air samples and pure gas samples. A high-resolution double monochromator was used with a C31034A-02 PM tube to count the photons scattered from a low-powered laser beam (1--2 watts). Standard high-speed modular electronics (approximately 10 ns resolution) were used to process the output pulses. The ..delta..J = 0 vibrational bands of /sup 14/N/sup 15/N and /sup 16/O/sup 18/O were observed to be essentially free of all interference except dark noise of approximately 3 counts/sec. The adjacent rotational structure of /sup 14/N/sup 14/N and /sup 16/O/sup 16/O showed no appreciable overlap with the ..delta..J = 0 bands of interest. Detailed spectra, comparison of the Raman intensity ratios with mass spectrometer isotope ratios, and Raman cross section data for /sup 14/N/sup 15/N and /sup 16/O/sup 18/O are presented. The applicability of Raman scattering as a technique for precision measurement of isotope ratios is discussed.
Date: January 30, 1975
Creator: Bloom, S. D.; Harney, R. C. & Milanovich, F. P.
System: The UNT Digital Library
SOIL DESICCATION TECHNIQUES STRATEGIES FOR IMMOBILIZATION OF DEEP VADOSE CONTAMINANTS AT THE HANFORD CENTRAL PLATEAU (open access)

SOIL DESICCATION TECHNIQUES STRATEGIES FOR IMMOBILIZATION OF DEEP VADOSE CONTAMINANTS AT THE HANFORD CENTRAL PLATEAU

Deep vadose zone contamination poses some of the most difficult remediation challenges for the protection of groundwater at the Hanford Site where processes and technologies are being developed and tested for use in the on-going effort to remediate mobile contamination in the deep vadose zone, the area deep beneath the surface. Historically, contaminants were discharged to the soil along with significant amounts of water, which continues to drive contaminants deeper in the vadose zone toward groundwater. Soil desiccation is a potential in situ remedial technology well suited for the arid conditions and the thick vadose zone at the Hanford Site. Desiccation techniques could reduce the advance of contaminants by removing the pore water to slow the rate of contaminants movement toward groundwater. Desiccation technologies have the potential to halt or slow the advance of contaminants in unsaturated systems, as well as aid in reduction of contaminants from these same areas. Besides reducing the water flux, desiccation also establishes capillary breaks that would require extensive rewetting to resume pore water transport. More importantly, these techniques have widespread application, whether the need is to isolate radio nuclides or address chemical contaminant issues. Three different desiccation techniques are currently being studied at Hanford.
Date: January 30, 2012
Creator: MW, BENECKE; GB, CHRONISTER & MJ, TRUEX
System: The UNT Digital Library