Multitasking mesoporous nanomaterials for biorefinery applications (open access)

Multitasking mesoporous nanomaterials for biorefinery applications

Mesoporous silica nanoparticles (MSNs) have attracted great interest for last two decades due to their unique and advantageous structural properties, such as high surface area, pore volume, stable mesostructure, tunable pore size and controllable particle morphology. The robust silica framework provides sites for organic modifications, making MSNs ideal platforms for adsorbents and supported organocatalysts. In addition, the pores of MSNs provide cavities/ channels for incorporation of metal and metal oxide nanoparticle catalysts. These supported metal nanoparticle catalysts benefit from confined local environments to enhance their activity and selectivity for various reactions. Biomass is considered as a sustainable feedstock with potential to replace diminishing fossil fuels for the production of biofuels. Among several strategies, one of the promising methods of biofuel production from biomass is to reduce the oxygen content of the feedstock in order to improve the energy density. This can be achieved by creating C-C bonds between biomass derived intermediates to increase the molecular weight of the final hydrocarbon molecules. In this context, pore size and organic functionality of MSNs are varied to obtain the ideal catalyst for a C-C bond forming reaction: the aldol condensation. The mechanistic aspects of this reaction in supported heterogeneous catalysts are explored. The …
Date: May 2, 2013
Creator: Kandel, Kapil
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Color Glass Condensate, Glasma and the Quark Gluon Plasma in the Context of Recent pPb Results from LHC (open access)

The Color Glass Condensate, Glasma and the Quark Gluon Plasma in the Context of Recent pPb Results from LHC

N/A
Date: February 2, 2013
Creator: McLerran, L.
Object Type: Article
System: The UNT Digital Library
Cast Stone Formulation At Higher Sodium Concentrations (open access)

Cast Stone Formulation At Higher Sodium Concentrations

A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased …
Date: October 2, 2013
Creator: Fox, K. M.; Edwards, T. A. & Roberts, K. B.
Object Type: Report
System: The UNT Digital Library
Final Report Development of Quartz Structures for Ultralow Background High Pressure Phototubes (open access)

Final Report Development of Quartz Structures for Ultralow Background High Pressure Phototubes

This report summarizes the activity of this grant. Due to circumstances beyond the control of the PI, this work was not completed and teh funds were returned to the agency at the end of the funding period.
Date: August 2, 2013
Creator: Webb, Robert C. & White, James T.
Object Type: Report
System: The UNT Digital Library
Axisymmetric curvature-driven instability in a model toroidal geometry (open access)

Axisymmetric curvature-driven instability in a model toroidal geometry

None
Date: July 2, 2013
Creator: Farmer, W. A. & Ryutov, D. D.
Object Type: Article
System: The UNT Digital Library
Toward a Single Mode Free Electron Laser for Coherent Hard X-Ray Experiments (open access)

Toward a Single Mode Free Electron Laser for Coherent Hard X-Ray Experiments

None
Date: July 2, 2013
Creator: Lee, Sooheyong; /SLAC, LCLS /DESY; Huang, Zhirong; Ding, Yuantao; Emma, Paul; /SLAC, LCLS et al.
Object Type: Article
System: The UNT Digital Library
Final Report: The Impact of Carbonate on Surface Protonation, Electron Transfer and Crystallization Reactions in Iron Oxide Nanoparticles and Colloids (open access)

Final Report: The Impact of Carbonate on Surface Protonation, Electron Transfer and Crystallization Reactions in Iron Oxide Nanoparticles and Colloids

This project addresses key issues of importance in the geochemical behavior of iron oxides and in the geochemical cycling of carbon and iron. For Fe, we are specifically studying the influence of carbonate on electron transfer reactions, solid phase transformations, and the binding of carbonate to reactive sites on the edges of particles. The emphasis on carbonate arises because it is widely present in the natural environment, is known to bind strongly to oxide surfaces, is reactive on the time scales of interest, and has a speciation driven by acid-base reactions. The geochemical behavior of carbonate strongly influences global climate change and CO{sub 2} sequestration technologies. Our goal is to answer key questions with regards to specific site binding, electron transfer reactions, and crystallization reactions of iron oxides that impact both the geochemical cycling of iron and CO{sub 2} species. Our work is focused on the molecular level description of carbonate chemistry in solution including the prediction of isotope fractionation factors. We have also done work on critical atmospheric species.
Date: July 2, 2013
Creator: Dixon, David Adams
Object Type: Report
System: The UNT Digital Library
Using Cumulative Number Densities to Compare Galaxies Across Cosmic Time (open access)

Using Cumulative Number Densities to Compare Galaxies Across Cosmic Time

None
Date: October 2, 2013
Creator: Behroozi, Peter; Marchesini, Danilo; Wechsler, Risa; Muzzin, Adam; Papovich, Casey & Stefanon, Mauro
Object Type: Report
System: The UNT Digital Library
A Variational Method for Interpolation Between Zone Centers in 2-D Geometry (open access)

A Variational Method for Interpolation Between Zone Centers in 2-D Geometry

None
Date: May 2, 2013
Creator: Brooks, E D & Szoke, A
Object Type: Report
System: The UNT Digital Library
Nonproliferation and National Security Training Global Security Through Science Partnerships (open access)

Nonproliferation and National Security Training Global Security Through Science Partnerships

N/A
Date: August 2, 2013
Creator: S., Rohatgi U. & Verdugo, D.
Object Type: Report
System: The UNT Digital Library
NV Energy Large-Scale Photovoltaic Integration Study: Intra-Hour Dispatch and AGC Simulation (open access)

NV Energy Large-Scale Photovoltaic Integration Study: Intra-Hour Dispatch and AGC Simulation

The uncertainty and variability with photovoltaic (PV) generation make it very challenging to balance power system generation and load, especially under high penetration cases. Higher reserve requirements and more cycling of conventional generators are generally anticipated for large-scale PV integration. However, whether the existing generation fleet is flexible enough to handle the variations and how well the system can maintain its control performance are difficult to predict. The goal of this project is to develop a software program that can perform intra-hour dispatch and automatic generation control (AGC) simulation, by which the balancing operations of a system can be simulated to answer the questions posed above. The simulator, named Electric System Intra-Hour Operation Simulator (ESIOS), uses the NV Energy southern system as a study case, and models the system’s generator configurations, AGC functions, and operator actions to balance system generation and load. Actual dispatch of AGC generators and control performance under various PV penetration levels can be predicted by running ESIOS. With data about the load, generation, and generator characteristics, ESIOS can perform similar simulations and assess variable generation integration impacts for other systems as well. This report describes the design of the simulator and presents the study results showing …
Date: January 2, 2013
Creator: Lu, Shuai; Etingov, Pavel V.; Meng, Da; Guo, Xinxin; Jin, Chunlian & Samaan, Nader A.
Object Type: Report
System: The UNT Digital Library
Materials Solutions for Hydrogen Delivery in Pipelines (open access)

Materials Solutions for Hydrogen Delivery in Pipelines

The main objective of the study is as follows: Identify steel compositions/microstructures suitable for construction of new pipeline infrastructure and evaluate the potential use of the existing steel pipeline infrastructure in high pressure gaseous hydrogen applications. The microstructures of four pipeline steels were characterized and tensile testing was conducted in gaseous hydrogen and helium at pressures of 5.5 MPa (800 psi), 11 MPa (1600 psi) and 20.7 MPa (3000 psi). Based on reduction of area, two of the four steels that performed the best across the pressure range were selected for evaluation of fracture and fatigue performance in gaseous hydrogen at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi). The basic format for this phase of the study is as follows: Microstructural characterization of volume fraction of phases in each alloy; Tensile testing of all four alloys in He and H{sub 2} at 5.5 MPa (800 psi), 11 MPa (1600 psi), and 20.7 MPa (3000 psi). RA performance was used to choose the two best performers for further mechanical property evaluation; Fracture testing (ASTM E1820) of two best tensile test performers in H{sub 2} at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi); Fatigue testing (ASTM E647) of …
Date: January 2, 2013
Creator: Ningileri, Shridas T.; Boggess, Todd A & Stalheim, Douglas
Object Type: Report
System: The UNT Digital Library
Measuring the hot-electron population using time-resolved, hard x-ray detectors on the NIF (open access)

Measuring the hot-electron population using time-resolved, hard x-ray detectors on the NIF

None
Date: August 2, 2013
Creator: Hohenberger, M.; Palmer, N. E.; LaCaille, G.; Dewald, E. L.; Divol, L.; Bond, E. J. et al.
Object Type: Article
System: The UNT Digital Library
Wide Bandgap Extrinsic Photoconductive Switches (open access)

Wide Bandgap Extrinsic Photoconductive Switches

None
Date: July 2, 2013
Creator: Sullivan, J S
Object Type: Thesis or Dissertation
System: The UNT Digital Library
A Description of the Mechanistic Dart - Thermal Dispersion Fuel Performance Code and Application to Irradiation Behavior Analysis of U-Mo/Al (open access)

A Description of the Mechanistic Dart - Thermal Dispersion Fuel Performance Code and Application to Irradiation Behavior Analysis of U-Mo/Al

None
Date: July 2, 2013
Creator: Ye, B.; Rest, J. & Kim, Y.S. (Nuclear Engineering Division)
Object Type: Report
System: The UNT Digital Library
Active Measurement of Memory Resource Consumption (open access)

Active Measurement of Memory Resource Consumption

None
Date: May 2, 2013
Creator: Guix, M C & Bronevetsky, G
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF GLASS AND GLASS CERAMIC PROPPANTS FROM GAS SHALE WELL DRILL CUTTINGS (open access)

DEVELOPMENT OF GLASS AND GLASS CERAMIC PROPPANTS FROM GAS SHALE WELL DRILL CUTTINGS

The objective of this study was to develop a method of converting drill cuttings from gas shale wells into high strength proppants via flame spheroidization and devitrification processing. Conversion of drill cuttings to spherical particles was only possible for small particle sizes (< 53 {micro}m) using a flame former after a homogenizing melting step. This size limitation is likely to be impractical for application as conventional proppants due to particle packing characteristics. In an attempt to overcome the particle size limitation, sodium and calcium were added to the drill cuttings to act as fluxes during the spheroidization process. However, the flame former remained unable to form spheres from the fluxed material at the relatively large diameters (0.5 - 2 mm) targeted for proppants. For future work, the flame former could be modified to operate at higher temperature or longer residence time in order to produce larger, spherical materials. Post spheroidization heat treatments should be investigated to tailor the final phase assemblage for high strength and sufficient chemical durability.
Date: October 2, 2013
Creator: Johnson, F. & Fox, K.
Object Type: Report
System: The UNT Digital Library
Algorithm Development for the Enhanced Radiological Nuclear Inspection and Evaluation (ERNIE) Tool (open access)

Algorithm Development for the Enhanced Radiological Nuclear Inspection and Evaluation (ERNIE) Tool

None
Date: August 2, 2013
Creator: Jacomb-Hood, T W
Object Type: Report
System: The UNT Digital Library
Empirical Parameterization of the K - \to Pi - Pi0 Pi0 Decay Dalitz Plot (open access)

Empirical Parameterization of the K - \to Pi - Pi0 Pi0 Decay Dalitz Plot

None
Date: July 2, 2013
Creator: Batley, J. R.; Culling, A. J.; Kalmus, G.; Lazzeroni, C.; Munday, D. J.; Slater, M. W. et al.
Object Type: Article
System: The UNT Digital Library
Monte Carlo Simulation Tool Installation and Operation Guide (open access)

Monte Carlo Simulation Tool Installation and Operation Guide

This document provides information on software and procedures for Monte Carlo simulations based on the Geant4 toolkit, the ROOT data analysis software and the CRY cosmic ray library. These tools have been chosen for its application to shield design and activation studies as part of the simulation task for the Majorana Collaboration. This document includes instructions for installation, operation and modification of the simulation code in a high cyber-security computing environment, such as the Pacific Northwest National Laboratory network. It is intended as a living document, and will be periodically updated. It is a starting point for information collection by an experimenter, and is not the definitive source. Users should consult with one of the authors for guidance on how to find the most current information for their needs.
Date: September 2, 2013
Creator: Aguayo Navarrete, Estanislao; Ankney, Austin S.; Berguson, Timothy J.; Kouzes, Richard T.; Orrell, John L.; Troy, Meredith D. et al.
Object Type: Report
System: The UNT Digital Library
Acquisition of an In-House X-ray Scattering Facility for Nanostructure Characterization and Student Training (open access)

Acquisition of an In-House X-ray Scattering Facility for Nanostructure Characterization and Student Training

This equipment grant was specifically dedicated to the development of a "state of the art" x-ray scattering facility...
Date: August 2, 2013
Creator: Schuller, Ivan K.
Object Type: Report
System: The UNT Digital Library
Phase 1 Feasibility Study, Canby Cascaded Geothermal Project, April 2, 2013 (open access)

Phase 1 Feasibility Study, Canby Cascaded Geothermal Project, April 2, 2013

A small community in Northern California is attempting to use a local geothermal resource to generate electrical power and cascade residual energy to an existing geothermal district heating system, greenhouse, and future fish farm and subsequent reinjection into the geothermal aquifer, creating a net-zero energy community, not including transportation.
Date: April 2, 2013
Creator: Merrick, Dale E.
Object Type: Report
System: The UNT Digital Library
Scalable Methods for Electronic Excitations and Optical Responses of Nanostructures: Mathematics to Algorithms to Observables (open access)

Scalable Methods for Electronic Excitations and Optical Responses of Nanostructures: Mathematics to Algorithms to Observables

Kohn-Sham density functional theory (DFT) is a powerful, well-established tool for the study of condensed phase electronic structure. However, there are still a number of situations where its applicability is limited. The basic theme of our research is the development of first principles electronic structure approaches for condensed matter that goes beyond what can currently be done with standard implementations ofKohn-Sham DFT. Our efforts to this end have focused on two classes or' methods. The first addresses the well-lmown inability of DFT to handle strong, many-body electron correlation effects. Our approach is a DFT -based embedding theory, to treat localized features (e.g. impurity, adsorbate, vacancy, etc.) embedded in a periodic, metallic crystal. A description for the embedded region is provided by explicitly correlated, ab initio wave function methods. DFT, as a fo1n1ally ground state theory, does not give a good description of excited states; an additional feature of our approach is the ability to obtain excitations localized in this region. We apply our method to a first-principles study of the adsorption of a single magnetic Co ada tom on non-magnetic Cu( 111 ), a known Kondo system whose behavior is governed by strong electron correlation. � The second class of …
Date: February 2, 2013
Creator: Carter, Emily A
Object Type: Report
System: The UNT Digital Library
Systems Level Regulation of Rhythmic Growth Rate and Biomass Accumulation in Grasses (open access)

Systems Level Regulation of Rhythmic Growth Rate and Biomass Accumulation in Grasses

Several breakthroughs have been recently made in our understanding of plant growth and biomass accumulation. It was found that plant growth is rhythmically controlled throughout the day by the circadian clock through a complex interplay of light and phytohormone signaling pathways. While plants such as the C4 energy crop sorghum (Sorghum bicolor (L.) Moench) and possibly the C3 grass (Brachypodium distachyon) also exhibit daily rhythms in growth rate, the molecular details of its regulation remain to be explored. A better understanding of diurnally regulated growth behavior in grasses may lead to species-specific mechanisms highly relevant to future strategies to optimize energy crop biomass yield. Here we propose to devise a systems approach to identify, in parallel, regulatory hubs associated with rhythmic growth in C3 and C4 plants. We propose to use rhythmicity in daily growth patterns to drive the discovery of regulatory network modules controlling biomass accumulation.
Date: May 2, 2013
Creator: Kay, Steve A.
Object Type: Report
System: The UNT Digital Library