Calculation Package for the Analysis of Performance of Cells 1-6, with Underdrain, of the Environmental Management Waste Management Facility Oak Ridge, Tennessee (open access)

Calculation Package for the Analysis of Performance of Cells 1-6, with Underdrain, of the Environmental Management Waste Management Facility Oak Ridge, Tennessee

This calculation package presents the results of an assessment of the performance of the 6 cell design of the Environmental Management Waste Management Facility (EMWMF). The calculations show that the new cell 6 design at the EMWMF meets the current WAC requirement. QA/QC steps were taken to verify the input/output data for the risk model and data transfer from modeling output files to tables and calculation.
Date: March 30, 2010
Creator: D., Gonzales
Object Type: Report
System: The UNT Digital Library
Effects of Down- and Up-regulated Lignin Biosynthesis in Populus of Soil Carbon Transformation and Storage (open access)

Effects of Down- and Up-regulated Lignin Biosynthesis in Populus of Soil Carbon Transformation and Storage

Our objective is to understand how rates of soil C formation and plant biomass are influenced by changes in plant growth and performance resulting from lowered lignin and altered lignin S/G ratios. A greenhouse study of the effects of altered lignin in SOC formation and plant biomass has been completed as of November 2009. Wild-type (control) and three transgenic aspen lines expressing reduced stem lignin concentrations and/or increased syringyl (S) to guaiacyl (G) ratio lignin were grown in greenhouse mesocosms. Soil was collected from the Colorado Central Plains Experimental Range (CPER) northeast of Fort Collins, Colorado. The Colorado soil is an Olney fine sandy loam (fine-loamy, mixed, superactive, mesic Ultic Haplargrid). Plants at the surface mineral soil up to 5 cm depth were removed and the underlying soil was sampled to a depth of 30 cm. Soils were immediately shipped to Reno, NV. This C4 soil was then used to trace belowground C inputs by the C3 plants into the soil using the 13C natural abundance methods as described in the DOE proposal. Transgenic quaking aspen were generated by the Forest Biotechnology Group at North Carolina State University (NCSU) using Agrobacterium-mediated transformation, the seedlings were then shipped to Reno, NV. …
Date: March 30, 2010
Creator: Chiang, Vincent, L. & Pregitzer, Kurt, S.
Object Type: Report
System: The UNT Digital Library

Fuel Cell Power Model for CHP and CHHP Economics and Performance Analysis

This presentation describes the fuel cell power model for CHP and CHHP economics and performance analysis.
Date: March 30, 2010
Creator: Steward, D. & Penev, M.
Object Type: Presentation
System: The UNT Digital Library
GyPSuM: A Detailed Tomographic Model of Mantle Density and Seismic Wave Speeds (open access)

GyPSuM: A Detailed Tomographic Model of Mantle Density and Seismic Wave Speeds

GyPSuM is a tomographic model fo mantle seismic shear wave (S) speeds, compressional wave (P) speeds and detailed density anomalies that drive mantle flow. the model is developed through simultaneous inversion of seismic body wave travel times (P and S) and geodynamic observations while considering realistic mineral physics parameters linking the relative behavior of mantle properties (wave speeds and density). Geodynamic observations include the (up to degree 16) global free-air gravity field, divergence of the tectonic plates, dynamic topography of the free surface, and the flow-induced excess ellipticity of the core-mantle boundary. GyPSuM is built with the philosophy that heterogeneity that most closely resembles thermal variations is the simplest possible solution. Models of the density field from Earth's free oscillations have provided great insight into the density configuration of the mantle; but are limited to very long-wavelength solutions. Alternatively, simply scaling higher resolution seismic images to density anomalies generates density fields that do not satisfy geodynamic observations. The current study provides detailed density structures in the mantle while directly satisfying geodynamic observations through a joint seismic-geodynamic inversion process. Notable density field observations include high-density piles at the base of the superplume structures, supporting the fundamental results of past normal mode …
Date: March 30, 2010
Creator: Simmons, N A; Forte, A M; Boschi, L & Grand, S P
Object Type: Article
System: The UNT Digital Library
HYDROGEN GENERATION FROM SLUDGE SAMPLE BOTTLES CAUSED BY RADIOLYSIS AND CHEMISTRY WITH CONCETNRATION DETERMINATION IN A STANDARD WASTE BOX (SWB) OR DRUM FOR TRANSPORT (open access)

HYDROGEN GENERATION FROM SLUDGE SAMPLE BOTTLES CAUSED BY RADIOLYSIS AND CHEMISTRY WITH CONCETNRATION DETERMINATION IN A STANDARD WASTE BOX (SWB) OR DRUM FOR TRANSPORT

A volume of 600 mL of sludge, in 4.1 L sample bottles (Appendix 7.6), will be placed in either a Super Pig (Ref. 1) or Piglet (Ref. 2, 3) based on shielding requirements (Ref. 4). Two Super Pigs will be placed in a Standard Waste Box (SWB, Ref. 5), as their weight exceeds the capacity of a drum; two Piglets will be placed in a 55-gallon drum (shown in Appendix 7.2). The generation of hydrogen gas through oxidation/corrosion of uranium metal by its reaction with water will be determined and combined with the hydrogen produced by radiolysis. The hydrogen concentration in the 55-gallon drum and SWB will be calculated to show that the lower flammability limit of 5% hydrogen is not reached. The inner layers (i.e., sample bottle, bag and shielded pig) in the SWB and drum will be evaluated to assure no pressurization occurs as the hydrogen vents from the inner containers (e.g., shielded pigs, etc.). The reaction of uranium metal with anoxic liquid water is highly exothermic; the heat of reaction will be combined with the source term decay heat, calculated from Radcalc, to show that the drum and SWB package heat load limits are satisfied. This analysis …
Date: March 30, 2010
Creator: DL, RILEY; AE, BRIDGES & WS, EDWARDS
Object Type: Report
System: The UNT Digital Library
The Impact of Rate Design and Net Metering on the Bill Savings from Distributed PV for Residential Customers in California (open access)

The Impact of Rate Design and Net Metering on the Bill Savings from Distributed PV for Residential Customers in California

Net metering has become a widespread policy in the U.S. for supporting distributed photovoltaics (PV) adoption. Though specific design details vary, net metering allows customers with PV to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption - in effect, compensating the PV generation at retail electricity rates (Rose et al. 2009). While net metering has played an important role in jump-starting the residential PV market in the U.S., challenges to net metering policies have emerged in a number of states and contexts, and alternative compensation methods are under consideration. Moreover, one inherent feature of net metering is that the value of the utility bill savings it provides to customers with PV depends heavily on the structure of the underlying retail electricity rate, as well as on the characteristics of the customer and PV system. Consequently, the value of net metering - and the impact of moving to alternative compensation mechanisms - can vary substantially from one customer to the next. For these reasons, it is important for policymakers and others that seek to support the development of distributed PV to understand both how the bill savings varies …
Date: March 30, 2010
Creator: Darghouth, Naim; Barbose, Galen & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library
MicroCT-Based Skeletal Models for Use in Tomographic Voxel Phantoms for Radiological Protection (open access)

MicroCT-Based Skeletal Models for Use in Tomographic Voxel Phantoms for Radiological Protection

ABSTRACT The University of Florida (UF) proposes to develop two high-resolution image-based skeletal dosimetry models for direct use by ICRP Committee 2’s Task Group on Dose Calculation in their forthcoming Reference Voxel Male (RVM) and Reference Voxel Female (RVF) whole-body dosimetry phantoms. These two phantoms are CT-based, and thus do not have the image resolution to delineate and perform radiation transport modeling of the individual marrow cavities and bone trabeculae throughout their skeletal structures. Furthermore, new and innovative 3D microimaging techniques will now be required for the skeletal tissues following Committee 2’s revision of the target tissues of relevance for radiogenic bone cancer induction. This target tissue had been defined in ICRP Publication 30 as a 10-m cell layer on all bone surfaces of trabecular and cortical bone. The revised target tissue is now a 50-m layer within the marrow cavities of trabecular bone only and is exclusive of the marrow adipocytes. Clearly, this new definition requires the use of 3D microimages of the trabecular architecture not available from past 2D optical studies of the adult skeleton. With our recent acquisition of two relatively young cadavers (males of age 18-years and 40-years), we will develop a series of reference skeletal …
Date: March 30, 2010
Creator: Bolch, Wesley
Object Type: Report
System: The UNT Digital Library
Numerical Stochastic Homogenization Method and Multiscale Stochastic Finite Element Method - A Paradigm for Multiscale Computation of Stochastic PDEs (open access)

Numerical Stochastic Homogenization Method and Multiscale Stochastic Finite Element Method - A Paradigm for Multiscale Computation of Stochastic PDEs

Multiscale modeling of stochastic systems, or uncertainty quantization of multiscale modeling is becoming an emerging research frontier, with rapidly growing engineering applications in nanotechnology, biotechnology, advanced materials, and geo-systems, etc. While tremendous efforts have been devoted to either stochastic methods or multiscale methods, little combined work had been done on integration of multiscale and stochastic methods, and there was no method formally available to tackle multiscale problems involving uncertainties. By developing an innovative Multiscale Stochastic Finite Element Method (MSFEM), this research has made a ground-breaking contribution to the emerging field of Multiscale Stochastic Modeling (MSM) (Fig 1). The theory of MSFEM basically decomposes a boundary value problem of random microstructure into a slow scale deterministic problem and a fast scale stochastic one. The slow scale problem corresponds to common engineering modeling practices where fine-scale microstructure is approximated by certain effective constitutive constants, which can be solved by using standard numerical solvers. The fast scale problem evaluates fluctuations of local quantities due to random microstructure, which is important for scale-coupling systems and particularly those involving failure mechanisms. The Green-function-based fast-scale solver developed in this research overcomes the curse-of-dimensionality commonly met in conventional approaches, by proposing a random field-based orthogonal expansion approach. …
Date: March 30, 2010
Creator: Xu, X. Frank
Object Type: Report
System: The UNT Digital Library
Power scaling analysis of fiber lasers and amplifiers based on non-silica materials (open access)

Power scaling analysis of fiber lasers and amplifiers based on non-silica materials

A developed formalism for analyzing the power scaling of diffraction limited fiber lasers and amplifiers is applied to a wider range of materials. Limits considered include thermal rupture, thermal lensing, melting of the core, stimulated Raman scattering, stimulated Brillouin scattering, optical damage, bend induced limits on core diameter and limits to coupling of pump diode light into the fiber. For conventional fiber lasers based upon silica, the single aperture, diffraction limited power limit was found to be 36.6kW. This is a hard upper limit that results from an interaction of the stimulated Raman scattering with thermal lensing. This result is dependent only upon physical constants of the material and is independent of the core diameter or fiber length. Other materials will have different results both in terms of ultimate power out and which of the many limits is the determining factor in the results. Materials considered include silica doped with Tm and Er, YAG and YAG based ceramics and Yb doped phosphate glass. Pros and cons of the various materials and their current state of development will be assessed. In particular the impact of excess background loss on laser efficiency is discussed.
Date: March 30, 2010
Creator: Dawson, J W; Messerly, M J; Heebner, J E; Pax, P H; Sridharan, A K; Bullington, A L et al.
Object Type: Article
System: The UNT Digital Library
Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter (open access)

Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter

Isotopically labile organic hydrogen in fossil fuels occupies chemical positions that participate in isotopic exchange and in chemical reactions during thermal maturation from kerogen to bitumen, oil and gas. Carbon-bound organic hydrogen is isotopically far less exchangeable than hydrogen bound to nitrogen, oxygen, or sulfur. We explore why organic hydrogen isotope ratios express a relationship with organic nitrogen isotope ratios in kerogen at low to moderate maturity. We develop and apply new techniques to utilize organic D/H ratios in organic matter fractions and on a molecular level as tools for exploration for fossil fuels and for paleoenvironmental research. The scope of our samples includes naturally and artificially matured substrates, such as coal, shale, oil and gas.
Date: March 30, 2010
Creator: Schimmelmann, Arndt & Mastalerz, Maria
Object Type: Report
System: The UNT Digital Library
Valence-state Model of Strain-dependent Mn L2,3 X-ray Magnetic Circular Dichroism from Ferromagnetic Semiconductors (open access)

Valence-state Model of Strain-dependent Mn L2,3 X-ray Magnetic Circular Dichroism from Ferromagnetic Semiconductors

We present a valence-state model to explain the characteristics of a recently observed pre-edge feature in Mn L{sub 3} x-ray magnetic circular dichroism (XMCD) of ferromagnetic (Ga,Mn)As and (Al,Ga,Mn)As thin films. The prepeak XMCD shows a uniaxial anisotropy, contrary to the cubic symmetry of the main structures induced by the crystalline electric field. Reversing the strain in the host lattice reverses the sign of the uniaxial anisotropy. With increasing carrier localization, the prepeak height increases, indicating an increasing 3d character of the hybridized holes. Hence, the feature is ascribed to transitions from the Mn 2p core level to unoccupied p-d hybridized valence states. The characteristics of the prepeak are readily reproduced by the model calculation taking into account the symmetry of the strain-, spin-orbit-, and exchange-split valence states around the zone center.
Date: March 30, 2010
Creator: van der Laan, G.; Edmonds, K. W.; Arenholz, E.; Farley, N. R. S. & Gallagher, B. L.
Object Type: Article
System: The UNT Digital Library