Computational Fluid Dynamics (CFD) Modeling for High Rate Pulverized Coal Injection (PCI) into the Blast Furnace (open access)

Computational Fluid Dynamics (CFD) Modeling for High Rate Pulverized Coal Injection (PCI) into the Blast Furnace

Pulverized coal injection (PCI) into the blast furnace (BF) has been recognized as an effective way to decrease the coke and total energy consumption along with minimization of environmental impacts. However, increasing the amount of coal injected into the BF is currently limited by the lack of knowledge of some issues related to the process. It is therefore important to understand the complex physical and chemical phenomena in the PCI process. Due to the difficulty in attaining trus BF measurements, Computational fluid dynamics (CFD) modeling has been identified as a useful technology to provide such knowledge. CFD simulation is powerful for providing detailed information on flow properties and performing parametric studies for process design and optimization. In this project, comprehensive 3-D CFD models have been developed to simulate the PCI process under actual furnace conditions. These models provide raceway size and flow property distributions. The results have provided guidance for optimizing the PCI process.
Date: October 15, 2008
Creator: Zhou, Dr. Chenn
Object Type: Report
System: The UNT Digital Library
Associations between iron oxyhydroxide nanoparticle growth and metal adsorption/structural incorporation (open access)

Associations between iron oxyhydroxide nanoparticle growth and metal adsorption/structural incorporation

The interaction of metal ions and oxyanions with nanoscale mineral phases has not yet been extensively studied despite the increased recognition of their prevalence in natural systems as a significant component of geomedia. A combination of macroscopic uptake studies to investigate the adsorption behavior of As(V), Cu(II), Hg(II), and Zn(II) onto nanoparticulate goethite ({alpha}-FeOOH) as a function of aging time at elevated temperature (75 C) and synchrotron-based X-ray studies to track changes in both the sorption mode and the rate of nanoparticle growth reveal the effects that uptake has on particle growth. Metal(loid) species which sorb quickly to the iron oxyhydroxide particles (As(V), Cu(II)) appear to passivate the particle surface, impeding the growth of the nanoparticles with progressive aging; in contrast, species that sorb more slowly (Hg(II), Zn(II)) have considerably less impact on particle growth. Progressive changes in the speciation of these particular metals with time suggest shifts in the mode of metal uptake with time, possibly indicating structural incorporation of the metal(loid) into the nanoparticle; this is supported by the continued increase in uptake concomitant with particle growth, implying that metal species may transform from surface-sorbed species to more structurally incorporated forms. This type of incorporation would have implications …
Date: September 15, 2008
Creator: Kim, C. S.; Lentini, C. J. & Waychunas, G. A.
Object Type: Book
System: The UNT Digital Library
Design and analysis of mismatch probes for long oligonucleotide microarrays (open access)

Design and analysis of mismatch probes for long oligonucleotide microarrays

Nonspecific hybridization is currently a major concern with microarray technology. One of most effective approaches to estimating nonspecific hybridizations in oligonucleotide microarrays is the utilization of mismatch probes; however, this approach has not been used for longer oligonucleotide probes. Here, an oligonucleotide microarray was constructed to evaluate and optimize parameters for 50-mer mismatch probe design. A perfect match (PM) and 28 mismatch (MM) probes were designed for each of ten target genes selected from three microorganisms. The microarrays were hybridized with synthesized complementary oligonucleotide targets at different temperatures (e.g., 42, 45 and 50 C). In general, the probes with evenly distributed mismatches were more distinguishable than those with randomly distributed mismatches. MM probes with 3, 4 and 5 mismatched nucleotides were differentiated for 50-mer oligonucleotide probes hybridized at 50, 45 and 42 C, respectively. Based on the experimental data generated from this study, a modified positional dependent nearest neighbor (MPDNN) model was constructed to adjust the thermodynamic parameters of matched and mismatched dimer nucleotides in the microarray environment. The MM probes with four flexible positional mismatches were designed using the newly established MPDNN model and the experimental results demonstrated that the redesigned MM probes could yield more consistent hybridizations. Conclusions: …
Date: August 15, 2008
Creator: Deng, Ye; He, Zhili; Van Nostrand, Joy D. & Zhou, Jizhong
Object Type: Article
System: The UNT Digital Library
Magneto-optical study of the intermediate state in type-I superconductors: Effects of sample shape and applied current (open access)

Magneto-optical study of the intermediate state in type-I superconductors: Effects of sample shape and applied current

The magnetic flux structures in the intermediate state of bulk, pinning-free Type-I superconductors are studied using a high resolution magneto-optical imaging technique. Unlike most previous studies, this work focuses on the pattern formation of the coexisting normal and superconducting phases in the intermediate state. The influence of various parameters such as sample shape, structure defects (pinning) and applied current are discussed in relation to two distinct topologies: flux tubes (closed topology) and laminar (open topology). Imaging and magnetization measurements performed on samples of different shapes (cones, hemispheres and slabs), show that contrary to previous beliefs, the tubular structure is the equilibrium topology, but it is unstable toward defects and flux motion. Moreover, the application of current into a sample with the geometric barrier can replace an established laminar structure with flux tubes. At very high currents, however, there exists a laminar 'stripe pattern.' Quantitative analysis of the mean tube diameter is shown to be in good agreement with the prediction proposed by Goren and Tinkham. This is the first time that this model has been confirmed experimentally. Further research into the flux tube phase shows a direct correlation with the current loop model proposed in the 1990's by Goldstein, Jackson …
Date: August 15, 2008
Creator: Hoberg, Jacob
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Stanley Basin Sockeye Technical Oversight Committee : Meeting Summary, February 21, 2008, Columbia Basin Fish & Wildlife Authority Building, Portland, Oregon. (open access)
Development and Implementation of a Program Management Maturity Model (open access)

Development and Implementation of a Program Management Maturity Model

In 2006, Honeywell Federal Manufacturing & Technologies (FM&T) announced an updatedvision statement for the organization. The vision is “To be the most admired team within the NNSA [National Nuclear Security Administration] for our relentless drive to convert ideas into the highest quality products and services for National Security by applying the right technology, outstanding program management and best commercial practices.” The challenge to provide outstanding program management was taken up by the Program Management division and the Program Integration Office (PIO) of the company. This article describes how Honeywell developed and deployed a program management maturity model to drive toward excellence.
Date: December 15, 2008
Creator: Hartwig, Laura & Smith, Matt
Object Type: Article
System: The UNT Digital Library
Considerations for Emerging Markets for Energy Savings Certificates (open access)

Considerations for Emerging Markets for Energy Savings Certificates

None
Date: September 15, 2008
Creator: Friedman, Barry; Bird, Lori & Barbose, Galen
Object Type: Report
System: The UNT Digital Library
A Reactive Oxide Overlayer on Rh Nanoparticles during CO Oxidation and Its Size Dependence Studied by in Situ Ambient Pressure XPS (open access)

A Reactive Oxide Overlayer on Rh Nanoparticles during CO Oxidation and Its Size Dependence Studied by in Situ Ambient Pressure XPS

None
Date: September 15, 2008
Creator: Grass, Michael E.; Zhang, Yawen; Butcher, Derek R.; Park, Jeong Y.; Li, Yimin; Bluhm, Hendrik et al.
Object Type: Article
System: The UNT Digital Library
Preparation and Characterization of Chemical Plugs Based on Selected Hanford Waste Simulants (open access)

Preparation and Characterization of Chemical Plugs Based on Selected Hanford Waste Simulants

This report presents the results of preparation and characterization of chemical plugs based on selected Hanford Site waste simulants. Included are the results of chemical plug bench testing conducted in support of the M1/M6 Flow Loop Chemical Plugging/Unplugging Test (TP-RPP-WTP-495 Rev A). These results support the proposed plug simulants for the chemical plugging/ unplugging tests. Based on the available simulant data, a set of simulants was identified that would likely result in chemical plugs. The three types of chemical plugs that were generated and tested in this task consisted of: 1. Aluminum hydroxide (NAH), 2. Sodium aluminosilicate (NAS), and 3. Sodium aluminum phosphate (NAP). While both solvents, namely 2 molar (2 M) nitric acid (HNO3) and 2 M sodium hydroxide (NaOH) at 60°C, used in these tests were effective in dissolving the chemical plugs, the 2 M nitric acid was significantly more effective in dissolving the NAH and NAS plugs. The caustic was only slightly more effecting at dissolving the NAP plug. In the bench-scale dissolution tests, hot (60°C) 2 M nitric acid was the most effective solvent in that it completely dissolved both NAH and NAS chemical plugs much faster (1.5 – 2 x) than 2 M sodium hydroxide. …
Date: September 15, 2008
Creator: Mattigod, Shas V.; Wellman, Dawn M.; Parker, Kent E.; Cordova, Elsa A.; Gunderson, Katie M.; Baum, Steven R. et al.
Object Type: Report
System: The UNT Digital Library
Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect (open access)

Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect

Corrosion of steel canisters, stored in a repository for spent fuel and high-level nuclear wastes, leads to the generation and accumulation of hydrogen gas in the backfilled emplacement tunnels, which may significantly affect long-term repository safety. Previous studies used H{sub 2} generation rates based on the volume of the waste or canister material and the stoichiometry of the corrosion reaction. However, iron corrosion and H{sub 2} generation rates vary with time, depending on factors such as amount of iron, water availability, water contact area, and aqueous and solid chemistry. To account for these factors and feedback mechanisms, we developed a chemistry model related to iron corrosion, coupled with two-phase (liquid and gas) flow phenomena that are driven by gas-pressure buildup associated with H{sub 2} generation and water consumption. Results indicate that by dynamically calculating H{sub 2} generation rates based on a simple model of corrosion chemistry, and by coupling this corrosion reaction with two-phase flow processes, the degree and extent of gas pressure buildup could be much smaller compared to a model that neglects the coupling between flow and reactive transport mechanisms. By considering the feedback of corrosion chemistry, the gas pressure increases initially at the canister, but later decreases …
Date: October 15, 2008
Creator: Xu, T.; Senger, R. & Finsterle, S.
Object Type: Article
System: The UNT Digital Library
Final Report of the Simulation Optimization Task Force (open access)

Final Report of the Simulation Optimization Task Force

This is the final report of the ATLAS Simulation Optimization Task Force, establishedin June of 2007. This note justifies the selected Geant4 version, physics list, and range cuts to be used by the default ATLAS simulation for initial data taking and beyond. The current status of several projects, including detector description, simulation validation, studies of additional Geant4 parameters, and cavern background, are reported.
Date: December 15, 2008
Creator: Collaboration, ATLAS; Rimoldi, A.; Carli, T.; Dell'Acqua, A.; Froidevaux, D.; Gianotti, F. et al.
Object Type: Article
System: The UNT Digital Library
Atomic structure of nanometer-sized amorphous TiO2 (open access)

Atomic structure of nanometer-sized amorphous TiO2

Amorphous titania (TiO{sub 2}) is an important precursor for synthesis of single-phase nanocrystalline anatase. We synthesized x-ray amorphous titania by hydrolysis of titanium ethoxide at the ice point. Transmission electron microscopy examination and nitrogen gas adsorption indicated the particle size of the synthesized titania is {approx} 2 nm. Synchrotron wide-angle x-ray scattering (WAXS) was used to probe the atomic correlations in this amorphous sample. Atomic pair-distribution function (PDF) derived from Fourier transform of the WAXS data was used for reverse Monte Carlo (RMC) simulations of the atomic structure of the amorphous TiO{sub 2} nanoparticles. Molecular dynamics simulations were used to generate input structures for the RMC. X-ray absorption spectroscopy (XAS) simulations were used to screen candidate structures obtained from the RMC by comparing with experimental XAS data. The structure model that best describes both the WAXS and XAS data shows that an amorphous TiO{sub 2} particle consists of a highly distorted shell and a small strained anatase-like crystalline core. The average coordination number of Ti is 5.3 and most Ti-O bonds are populated around 1.940 {angstrom}. Relative to bulk TiO{sub 2}, the reduction of the coordination number is primarily due to the truncation of the Ti-O octahedra at the amorphous …
Date: October 15, 2008
Creator: Zhang, H.; Chen, B.; Banfield, J. F. & Waychunas, G. A.
Object Type: Article
System: The UNT Digital Library
Recent advances in well-based monitoring of CO2 sequestration (open access)

Recent advances in well-based monitoring of CO2 sequestration

Recent CO{sub 2} sequestration pilot projects have implemented novel approaches to well-based subsurface monitoring aimed at increasing the amount and quality of information available from boreholes. Some of the drivers for the establishment of new well-based technologies and methodologies arise from: (1) the need for data to assess physical and geochemical subsurface processes associated with CO{sub 2} emplacement; (2) the high cost of deep boreholes and need to maximize data yield from each; (3) need for increased temporal resolution to observe plume evolution; (4) a lack of established processes and technologies for integrated permanent sensors in the oil and gas industry; and (5) a lack of regulatory guidance concerning the amount, type, and duration of monitoring required for long-term performance confirmation of a CO{sub 2} storage site. In this paper we will examine some of the latest innovations in well-based monitoring and present examples of integrated monitoring programs.
Date: October 15, 2008
Creator: Freifeld, B.; Daley, T.; Hovorka, S.; Henninges, J.; Underschultz, J. & Sharma, S.
Object Type: Article
System: The UNT Digital Library
Independent Verification Survey Report for the Offsite Portion of the Potential Release Site-7 Abandoned Sanitary Line, Miamisburg Closure Project, Miamisburg, Ohio (open access)

Independent Verification Survey Report for the Offsite Portion of the Potential Release Site-7 Abandoned Sanitary Line, Miamisburg Closure Project, Miamisburg, Ohio

The ORISE objective was to confirm that the remedial action process implemented by the contractor was in accordance with the PRS-7 Work Package. Following removal of the sanitary line, the soil beneath the line would be sampled to determine if remediation was required (ARC 2007a).
Date: August 15, 2008
Creator: Weaver, P. C.
Object Type: Report
System: The UNT Digital Library
Scrape-off Layer Current Model for Filament Structure Observed during Edge Localized Modes (ELMs) in the DIII-D Tokamak (open access)

Scrape-off Layer Current Model for Filament Structure Observed during Edge Localized Modes (ELMs) in the DIII-D Tokamak

The plasma in tokamaks often exhibits a relaxation oscillation called the edge localized mode (ELM), which is generally attributed to MHD instability driven by strong gradients at the plasma boundary. It is shown here that field-aligned currents flowing just outside the boundary may also play a role in the ELM process. The poloidal perturbation magnetic field during ELMs in the DIII–D tokamak calculated from measured currents can reproduce prominent observed features, including a narrow magnetic structure at the outboard midplane similar to filaments observed earlier in DIII–D and NSTX.
Date: April 15, 2008
Creator: Hironori Takahashi, E. D. Fredrickson, and M.J. Schaffer
Object Type: Report
System: The UNT Digital Library
Technical Basis of Scaling Relationships for the Pretreatment Engineering Platform (open access)

Technical Basis of Scaling Relationships for the Pretreatment Engineering Platform

Pacific Northwest National Laboratory has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Waste Treatment Plant (RPP-WTP) project to perform research and development activities. The Pretreatment Engineering Platform (PEP) is being designed and constructed as part of a plan to respond to an issue raised by the WTP External Flowsheet Review Team (EFRT) entitled “Undemonstrated Leaching Processes” and numbered M12. The PEP replicates the WTP leaching process using prototypic equipment and control strategies. The approach for scaling PEP performance data to predict WTP performance is critical to the successful resolution of the EFRT issue. This report describes the recommended PEP scaling approach, PEP data interpretation and provides recommendations on test conduct and data requirements.
Date: July 15, 2008
Creator: Kuhn, William L.; Arm, Stuart T.; Huckaby, James L.; Kurath, Dean E. & Rassat, Scot D.
Object Type: Report
System: The UNT Digital Library
Modeling the diffusion of Na+ in compacted water-saturated Na-bentonite as a function of pore water ionic strength (open access)

Modeling the diffusion of Na+ in compacted water-saturated Na-bentonite as a function of pore water ionic strength

Assessments of bentonite barrier performance in waste management scenarios require an accurate description of the diffusion of water and solutes through the barrier. A two-compartment macropore/nanopore model (on which smectite interlayer nanopores are treated as a distinct compartment of the overall pore space) was applied to describe the diffusion of {sup 22}Na{sup +} in compacted, water-saturated Na-bentonites and then compared with the well-known surface diffusion model. The two-compartment model successfully predicted the observed weak ionic strength dependence of the apparent diffusion coefficient (D{sub a}) of Na{sup +}, whereas the surface diffusion model did not, thus confirming previous research indicating the strong influence of interlayer nanopores on the properties of smectite clay barriers. Since bentonite mechanical properties and pore water chemistry have been described successfully with two-compartment models, the results in the present study represent an important contribution toward the construction of a comprehensive two-compartment model of compacted bentonite barriers.
Date: August 15, 2008
Creator: Bourg, I.C.; Sposito, G. & Bourg, A.C.M.
Object Type: Article
System: The UNT Digital Library
Lower Snake River Fish and Wildlife Compensation Plan Grande Ronde and Imnaha Basins Annual Operation Plan for the Period of February 1, 2008 - January 31, 2009. (open access)

Lower Snake River Fish and Wildlife Compensation Plan Grande Ronde and Imnaha Basins Annual Operation Plan for the Period of February 1, 2008 - January 31, 2009.

None
Date: February 15, 2008
Creator: Oregon. Department of Fish and Wildlife.
Object Type: Report
System: The UNT Digital Library
A Reactive Oxide Overlayer on Rh Nanoparticles during CO Oxidation and Its Size Dependence Studied by in Situ Ambient Pressure XPS (open access)

A Reactive Oxide Overlayer on Rh Nanoparticles during CO Oxidation and Its Size Dependence Studied by in Situ Ambient Pressure XPS

CO oxidation is one of the most studied heterogeneous reactions, being scientifically and industrially important, particularly for removal of CO from exhaust streams and preferential oxidation for hydrogen purification in fuel cell applications. The precious metals Ru, Rh, Pd, Pt, and Au are most commonly used for this reaction because of their high activity and stability. Despite the wealth of experimental and theoretical data, it remains unclear what is the active surface for CO oxidation under catalytic conditions for these metals. In this communication, we utilize in situ synchrotron ambient pressure X-ray photoelectron spectroscopy (APXPS) to monitor the oxidation state at the surface of Rh nanoparticles during CO oxidation and demonstrate that the active catalyst is a surface oxide, the formation of which is dependent on particle size. The amount of oxide formed and the reaction rate both increase with decreasing particle size.
Date: September 15, 2008
Creator: Grass, Michael E.; Zhang, Yawen; Butcher, Derek R.; Park, Jeong Y.; Li, Yimin; Bluhm, Hendrik et al.
Object Type: Article
System: The UNT Digital Library
FY 2007 Progress Report for Upper Columbia United Tribes' Regional Coordination. (open access)

FY 2007 Progress Report for Upper Columbia United Tribes' Regional Coordination.

This report is a summary of activities conducted over the fiscal year 2007 contract period to fulfill requirements to coordinate Upper Columbia United Tribes (UCUT) interests within the Columbia River Basin. This coordination was specific to the implementation of portions of the Integrated Fish and Wildlife Program within the purview of the Northwest Power and Conservation Council and Bonneville Power Administration.
Date: December 15, 2008
Creator: Michel, D.R.
Object Type: Report
System: The UNT Digital Library
Stripping foils at RHIC (open access)

Stripping foils at RHIC

There are two major science programs at the Relativistic Heavy Ion Collider (RHIC). These are the heavy ion program, which collides beams of fully stripped ions, and the polarized proton program. A wide variety of stripper foils and carbon targets are used throughout the RHIC accelerator chain to facilitate these collisions. Each stripper and target has unique properties and functions. Those characteristics will be discussed, as well as recent efforts to improve their performance.
Date: September 15, 2008
Creator: Steski,D.B. & Thieberger, P.
Object Type: Article
System: The UNT Digital Library
Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials (open access)

Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials

Matrix-assisted laser desorption/ionization(MALDI) mass spectrometry(MS) has been widely used for analysis of biological molecules, especially macromolecules such as proteins. However, MALDI MS has a problem in small molecule (less than 1 kDa) analysis because of the signal saturation by organic matrixes in the low mass region. In imaging MS (IMS), inhomogeneous surface formation due to the co-crystallization process by organic MALDI matrixes limits the spatial resolution of the mass spectral image. Therefore, to make laser desorption/ionization (LDI) MS more suitable for mass spectral profiling and imaging of small molecules directly from raw biological tissues, LDI MS protocols with various alternative assisting materials were developed and applied to many biological systems of interest. Colloidal graphite was used as a matrix for IMS of small molecules for the first time and methodologies for analyses of small metabolites in rat brain tissues, fruits, and plant tissues were developed. With rat brain tissues, the signal enhancement for cerebroside species by colloidal graphite was observed and images of cerebrosides were successfully generated by IMS. In addition, separation of isobaric lipid ions was performed by imaging tandem MS. Directly from Arabidopsis flowers, flavonoids were successfully profiled and heterogeneous distribution of flavonoids in petals was observed for …
Date: May 15, 2008
Creator: Cha, Sangwon
Object Type: Thesis or Dissertation
System: The UNT Digital Library
High Density n-Si/n-TiO2 Core/Shell Nanowire Arrays with Enhanced Photoactivity (open access)

High Density n-Si/n-TiO2 Core/Shell Nanowire Arrays with Enhanced Photoactivity

There are currently great needs to develop low-cost inorganic materials that can efficiently perform solar water splitting as photoelectrolysis of water into hydrogen and oxygen has significant potential to provide clean energy. We investigate the Si/TiO2 nanowire heterostructures to determine their potential for the photooxidation of water. We observed that highly dense Si/TiO2 core/shell nanowire arrays enhanced the photocurrent by 2.5 times compared to planar Si/TiO2 structure due to their low reflectance and high surface area. We also showed that n-Si/n-TiO2 nanowire arrays exhibited a larger photocurrent and open circuit voltage than p-Si/n-TiO2 nanowires due to a barrier at the heterojunction.
Date: November 15, 2008
Creator: Hwang, Yun Jeong; Boukai, Akram & Yang, Peidong
Object Type: Article
System: The UNT Digital Library
The effects of gas-fluid-rock interactions on CO2 injection and storage: Insights from reactive transport modeling (open access)

The effects of gas-fluid-rock interactions on CO2 injection and storage: Insights from reactive transport modeling

Possible means of reducing atmospheric CO{sub 2} emissions include injecting CO{sub 2} in petroleum reservoirs for Enhanced Oil Recovery or storing CO{sub 2} in deep saline aquifers. Large-scale injection of CO{sub 2} into subsurface reservoirs would induce a complex interplay of multiphase flow, capillary trapping, dissolution, diffusion, convection, and chemical reactions that may have significant impacts on both short-term injection performance and long-term fate of CO{sub 2} storage. Reactive Transport Modeling is a promising approach that can be used to predict the spatial and temporal evolution of injected CO{sub 2} and associated gas-fluid-rock interactions. This presentation will summarize recent advances in reactive transport modeling of CO{sub 2} storage and review key technical issues on (1) the short- and long-term behavior of injected CO{sub 2} in geological formations; (2) the role of reservoir mineral heterogeneity on injection performance and storage security; (3) the effect of gas mixtures (e.g., H{sub 2}S and SO{sub 2}) on CO{sub 2} storage; and (4) the physical and chemical processes during potential leakage of CO{sub 2} from the primary storage reservoir. Simulation results suggest that CO{sub 2} trapping capacity, rate, and impact on reservoir rocks depend on primary mineral composition and injecting gas mixtures. For example, models …
Date: October 15, 2008
Creator: Xiao, Y.; Xu, T. & Pruess, K.
Object Type: Article
System: The UNT Digital Library