Molecular analysis of the metabolic rates of discrete subsurface populations of sulfate reducers (open access)

Molecular analysis of the metabolic rates of discrete subsurface populations of sulfate reducers

Elucidating the in situ metabolic activity of phylogenetically diverse populations of sulfate-reducing microorganisms that populate anoxic sedimentary environments is key to understanding subsurface ecology. Previous pure culture studies have demonstrated that transcript abundance of dissimilatory (bi)sulfite reductase genes is correlated with the sulfate reducing activity of individual cells. To evaluate whether expression of these genes was diagnostic for subsurface communities, dissimilatory (bi)sulfite reductase gene transcript abundance in phylogenetically distinct sulfate-reducing populations was quantified during a field experiment in which acetate was added to uranium-contaminated groundwater. Analysis of dsrAB sequences prior to the addition of acetate indicated that Desulfobacteraceae, Desulfobulbaceae, and Syntrophaceae-related sulfate reducers were the most abundant. Quantifying dsrB transcripts of the individual populations suggested that Desulfobacteraceae initially had higher dsrB transcripts per cell than Desulfobulbaceae or Syntrophaceae populations, and that the activity of Desulfobacteraceae increased further when the metabolism of dissimilatory metal reducers competing for the added acetate declined. In contrast, dsrB transcript abundance in Desulfobulbaceae and Syntrophaceae remained relatively constant, suggesting a lack of stimulation by added acetate. The indication of higher sulfate-reducing activity in the Desulfobacteraceae was consistent with the finding that Desulfobacteraceae became the predominant component of the sulfate-reducing community. Discontinuing acetate additions resulted in a …
Date: April 1, 2011
Creator: Miletto, M.; Williams, K.H.; N'Guessan, A.L. & Lovley, D.R.
System: The UNT Digital Library
Can Ionic Liquids Be Used As Templating Agents For Controlled Design of Uranium-Containing Nanomaterials? (open access)

Can Ionic Liquids Be Used As Templating Agents For Controlled Design of Uranium-Containing Nanomaterials?

Nanostructured uranium oxides have been prepared in ionic liquids as templating agents. Using the ionic liquids as reaction media for inorganic nanomaterials takes advantage of the pre-organized structure of the ionic liquids which in turn controls the morphology of the inorganic nanomaterials. Variation of ionic liquid cation structure was investigated to determine the impact on the uranium oxide morphologies. For two ionic liquid cations, increasing the alkyl chain length increases the aspect ratio of the resulting nanostructured oxides. Understanding the resulting metal oxide morphologies could enhance fuel stability and design.
Date: April 9, 2013
Creator: Visser, A.; Bridges, N. & Tosten, M.
System: The UNT Digital Library
IMPROVED COMPUTATIONAL NEUTRONICS METHODS AND VALIDATION PROTOCOLS FOR THE ADVANCED TEST REACTOR (open access)

IMPROVED COMPUTATIONAL NEUTRONICS METHODS AND VALIDATION PROTOCOLS FOR THE ADVANCED TEST REACTOR

The Idaho National Laboratory (INL) is in the process of modernizing the various reactor physics modeling and simulation tools used to support operation and safety assurance of the Advanced Test Reactor (ATR). Key accomplishments so far have encompassed both computational as well as experimental work. A new suite of stochastic and deterministic transport theory based reactor physics codes and their supporting nuclear data libraries (HELIOS, KENO6/SCALE, NEWT/SCALE, ATTILA, and an extended implementation of MCNP5) has been installed at the INL. Corresponding models of the ATR and ATRC are now operational with all five codes, demonstrating the basic feasibility of the new code packages for their intended purpose. Of particular importance, a set of as-run core depletion HELIOS calculations for all ATR cycles since August 2009 was successfully completed during 2011. This demonstration supported a decision late in the year to proceed with the phased incorporation of the HELIOS methodology into the ATR fuel cycle management process beginning in 2012. On the experimental side of the project, new hardware was fabricated, measurement protocols were finalized, and the first four of six planned physics code validation experiments based on neutron activation spectrometry were conducted at the ATRC facility. Data analysis for the …
Date: April 1, 2012
Creator: Nigg, David W.; Nielsen, Joseph W.; Chase, Benjamin M.; Murray, Ronnie K. & Steuhm, Kevin A.
System: The UNT Digital Library
Experimental Demonstration of Femtosecond Two-Color X-Ray Free-Electron Lasers (open access)

Experimental Demonstration of Femtosecond Two-Color X-Ray Free-Electron Lasers

None
Date: April 9, 2013
Creator: Lutman, A. A.; Coffee, R.; Ding, Y.; Huang, Z.; Krzywinski, J.; Maxwell, T. et al.
System: The UNT Digital Library
Coherent electron cooling proof of principle instrumentation design (open access)

Coherent electron cooling proof of principle instrumentation design

The goal of the Coherent Electron Cooling Proof-of-Principle (CeC PoP) experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to longitudinally cool a single bunch of 40 GeV/u gold ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.
Date: April 15, 2012
Creator: M., Gassner D.; Litvinenko, V.; Michnoff, R.; Miller, T.; Minty, M. & Pinayev, I.
System: The UNT Digital Library
Quantification Of Aluminum Increase Factors for Curtainwall Design Using Finite Element Methods (open access)

Quantification Of Aluminum Increase Factors for Curtainwall Design Using Finite Element Methods

None
Date: April 30, 2013
Creator: Leininger, L D & Gallant, S M
System: The UNT Digital Library
Development of Offshore Wind Recommended Practice for U.S. Waters: Preprint (open access)

Development of Offshore Wind Recommended Practice for U.S. Waters: Preprint

This paper discusses how the American Petroleum Institute oil and gas standards were interfaced with International Electrotechnical Commission and other wind turbine and offshore industry standards to provide guidance for reliable engineering design practices for offshore wind energy systems.
Date: April 1, 2013
Creator: Musial, W. D.; Sheppard, R. E.; Dolan, D. & Naughton, B.
System: The UNT Digital Library
THE USE OF POLYMERS IN RADIOACTIVE WASTE PROCESSING SYSTEMS (open access)

THE USE OF POLYMERS IN RADIOACTIVE WASTE PROCESSING SYSTEMS

The Savannah River Site (SRS), one of the largest U.S. Department of Energy (DOE) sites, has operated since the early 1950s. The early mission of the site was to produce critical nuclear materials for national defense. Many facilities have been constructed at the SRS over the years to process, stabilize and/or store radioactive waste and related materials. The primary materials of construction used in such facilities are inorganic (metals, concrete), but polymeric materials are inevitably used in various applications. The effects of aging, radiation, chemicals, heat and other environmental variables must therefore be understood to maximize service life of polymeric components. In particular, the potential for dose rate effects and synergistic effects on polymeric materials in multivariable environments can complicate compatibility reviews and life predictions. The selection and performance of polymeric materials in radioactive waste processing systems at the SRS are discussed.
Date: April 15, 2013
Creator: Skidmore, E. & Fondeur, F.
System: The UNT Digital Library
Cosmography From Two-Image Lens Systems: Overcoming the Lens Profile Slope Degeneracy (open access)

Cosmography From Two-Image Lens Systems: Overcoming the Lens Profile Slope Degeneracy

None
Date: April 25, 2013
Creator: Suyu, S.H. & /UC, Santa Barbara /KIPAC, Menlo Park
System: The UNT Digital Library
Anisotropies in the Diffuse Gamma-Ray Background Measured By the Fermi LAT (open access)

Anisotropies in the Diffuse Gamma-Ray Background Measured By the Fermi LAT

None
Date: April 4, 2013
Creator: Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Ballet, J.; Barbiellini, G. et al.
System: The UNT Digital Library
Assessing the Battery Cost at Which Plug-In Hybrid Medium-Duty Parcel Delivery Vehicles Become Cost-Effective (open access)

Assessing the Battery Cost at Which Plug-In Hybrid Medium-Duty Parcel Delivery Vehicles Become Cost-Effective

The National Renewable Energy Laboratory (NREL) validated diesel-conventional and diesel-hybrid medium-duty parcel delivery vehicle models to evaluate petroleum reductions and cost implications of hybrid and plug-in hybrid diesel variants. The hybrid and plug-in hybrid variants are run on a field data-derived design matrix to analyze the effect of drive cycle, distance, engine downsizing, battery replacements, and battery energy on fuel consumption and lifetime cost. For an array of diesel fuel costs, the battery cost per kilowatt-hour at which the hybridized configuration becomes cost-effective is calculated. This builds on a previous analysis that found the fuel savings from medium duty plug-in hybrids more than offset the vehicles' incremental price under future battery and fuel cost projections, but that they seldom did so under present day cost assumptions in the absence of purchase incentives. The results also highlight the importance of understanding the application's drive cycle specific daily distance and kinetic intensity.
Date: April 1, 2013
Creator: Ramroth, L. A.; Gonder, J. D. & Brooker, A. D.
System: The UNT Digital Library
High precision measurements of the neutron spin structure in Hall A at Jlab (open access)

High precision measurements of the neutron spin structure in Hall A at Jlab

Conclusions of this presentation are: (1) JLab energy upgrade will offer new exciting opportunities to study the nucleon (spin) structure such as high precision, unexplored phase space, flavor decomposition; (2) Large technological efforts is in progress to optimally exploit these opportunities; (3) HallA will be the first hall to get the new beam, first experiment expected to run in 2014; (4) A1n likely one of the first experiments to take data in the new 12 GeV era; and (5) SIDIS exp. will follow in couple of years.
Date: April 1, 2012
Creator: Annand, R M; Cates, G; Cisbani, E; Franklin, G B; Liyanage, N; Puckett, A et al.
System: The UNT Digital Library
Surface structure of protonated R-plane-sapphire (1-102) studied by sum frequency vibrational spectroscopy (open access)

Surface structure of protonated R-plane-sapphire (1-102) studied by sum frequency vibrational spectroscopy

Sum frequency vibrational spectroscopy was used to study the protonated R-plane (1{bar 1}02 ) sapphire surface. The OH stretch vibrational spectra show that the surface is terminated with three hydroxyl moieties, two from AlOH{sub 2} and one from Al{sub 2}OH functional groups. The observed polarization dependence allows determination of the orientations of the three OH species. The results suggest that the protonated sapphire (1{bar 1}02 ) surface differs from an ideal stoichimetric termination in a manner consistent with previous X-ray surface diffraction (crystal truncation rod) studies. However, in order to best explain the observed hydrogenbonding arrangement, surface oxygen spacing determined from the X-ray diffraction study requires modification.
Date: April 1, 2011
Creator: Sung, J.; Zhang, L.; Tian, C.; Waychunas, G. A. & Shen, Y. R.
System: The UNT Digital Library
Variations in Map Products Demonstrated During the FRMAC Fukushima Daiichi Response (open access)

Variations in Map Products Demonstrated During the FRMAC Fukushima Daiichi Response

This presentation provides a brief summary of the Fukushima Daiichi disaster, discussion on map uses and production, early phase maps, intermediate phase maps, and late phase maps.
Date: April 3, 2012
Creator: Pemberton, W. J.
System: The UNT Digital Library
Summary of “Future of DIS” Working Group Session (open access)

Summary of “Future of DIS” Working Group Session

Despite the closure of the HERA accelerator in the past few years, much physics still remains to be understood, from the quark and gluon content of the nucleon/nucleus across all x to the still unknown spin structure of the proton. The 'Future of DIS' working group was dedicated to discussions on these and many other subjects. This paper represents a brief overview of the discussions. For further details, please refer to individual contributions.
Date: April 11, 2011
Creator: M., Lamont; Guzey, V. & Polini, A.
System: The UNT Digital Library
Stoichiometry control of the electronic properties of the LaAlO3/SrTiO3 heterointerface (open access)

Stoichiometry control of the electronic properties of the LaAlO3/SrTiO3 heterointerface

None
Date: April 30, 2013
Creator: Sato, H.K.; Bell, C.; Hikita, Y. & Hwang, H.Y.
System: The UNT Digital Library
Experimental Study of Turbulent Mixing in the Richtmyer-Meshkov Instability (open access)

Experimental Study of Turbulent Mixing in the Richtmyer-Meshkov Instability

None
Date: April 5, 2013
Creator: Weber, C R; Haehn, N S; Oakley, J; Rothamer, D & Bonazza, R
System: The UNT Digital Library
Gamma Lines without a Continuum: Thermal Models for the Fermi-LAT 130 GeV Gamma Line (open access)

Gamma Lines without a Continuum: Thermal Models for the Fermi-LAT 130 GeV Gamma Line

None
Date: April 5, 2013
Creator: Bai, Yang; /SLAC /Wisconsin U., Madison; Shelton, Jessie & U., /Yale
System: The UNT Digital Library
Rapid Impedance Spectrum Measurements for State-of-Health Assessment of Energy Storage Devices (open access)

Rapid Impedance Spectrum Measurements for State-of-Health Assessment of Energy Storage Devices

Harmonic compensated synchronous detection (HCSD) is a technique that can be used to measure wideband impedance spectra within seconds based on an input sum-of-sines signal having a frequency spread separated by harmonics. The battery (or other energy storage device) is excited with a sum-of-sines current signal that has a duration of at least one period of the lowest frequency. The voltage response is then captured and synchronously detected at each frequency of interest to determine the impedance spectra. This technique was successfully simulated using a simplified battery model and then verified with commercially available Sanyo lithium-ion cells. Simulations revealed the presence of a start-up transient effect when only one period of the lowest frequency is included in the excitation signal. This transient effect appears to only influence the low-frequency impedance measurements and can be reduced when a longer input signal is used. Furthermore, lithium-ion cell testing has indicated that the transient effect does not seem to impact the charge transfer resistance in the mid-frequency region. The degradation rates for the charge transfer resistance measured from the HCSD technique were very similar to the changes observed from standardized impedance spectroscopy methods. Results from these studies, therefore, indicate that HCSD is a …
Date: April 1, 2012
Creator: Christophersen, Jon P.; Morrison, John L.; Motloch, Chester G. & Morrison, William H.
System: The UNT Digital Library
Method to Branch and Bound Large SBO State Spaces (open access)

Method to Branch and Bound Large SBO State Spaces

Traditional Probabilistic Risk Assessment (PRA) me
Date: April 1, 2013
Creator: Tokuhiro, Akira & Hiromoto, Robert
System: The UNT Digital Library
A Laser Optical System to Remove Low Earth Orbit Space Debris (open access)

A Laser Optical System to Remove Low Earth Orbit Space Debris

None
Date: April 15, 2013
Creator: Phipps, C. R.; Baker, K. L.; Libby, S. B.; Liedahl, D. A.; Olivier, S. S.; Pleasance, L. D. et al.
System: The UNT Digital Library
Multiplexed gas spectroscopy using tunable VCSELs (open access)

Multiplexed gas spectroscopy using tunable VCSELs

Detection and identification of gas species using tunable laser diode laser absorption spectroscopy has been performed using vertical cavity surface emitting lasers (VCSEL). Two detection methods are compared: direct absorbance and wavelength modulation spectroscopy (WMS). In the first, the output of a DC-based laser is directly monitored to detect for any quench at the targeted specie wavelength. In the latter, the emission wavelength of the laser is modulated by applying a sinusoidal component on the drive current of frequency {omega}, and measuring the harmonics component (2{omega}) of the photo-detected current. This method shows a better sensitivity measured as signal to noise ratio, and is less susceptible to interference effects such as scattering or fouling. Gas detection was initially performed at room temperature and atmospheric conditions using VCSELs of emission wavelength 763 nm for oxygen and 1392 nm for water, scanning over a range of approximately 10 nm, sufficient to cover 5-10 gas specific absorption lines that enable identification and quantization of gas composition. The amplitude and frequency modulation parameters were optimized for each detected gas species, by performing two dimensional sweeps for both tuning current and either amplitude or frequency, respectively. We found that the highest detected signal is observed …
Date: April 10, 2012
Creator: Bond, T; Bond, S; McCarrick, J; Zumstein, J; Chang, A; Moran, B et al.
System: The UNT Digital Library
Next-to-Leading Order W 5-Jet Production at the LHC (open access)

Next-to-Leading Order W 5-Jet Production at the LHC

None
Date: April 9, 2013
Creator: Bern, Z.; Dixon, L. J.; Cordero, F. Febres; Hoeche, S.; Ita, H.; Kosower, D. A. et al.
System: The UNT Digital Library
Form factors from lattice QCD (open access)

Form factors from lattice QCD

Precision computation of hadronic physics with lattice QCD is becoming feasible. The last decade has seen precent-level calculations of many simple properties of mesons, and the last few years have seen calculations of baryon masses, including the nucleon mass, accurate to a few percent. As computational power increases and algorithms advance, the precise calculation of a variety of more demanding hadronic properties will become realistic. With this in mind, I discuss the current lattice QCD calculations of generalized parton distributions with an emphasis on the prospects for well-controlled calculations for these observables as well. I will do this by way of several examples: the pion and nucleon form factors and moments of the nucleon parton and generalized-parton distributions.
Date: April 1, 2012
Creator: Renner, Dru
System: The UNT Digital Library