Unmanned Vehicles for U.S. Naval Forces:  Background and Issues for Congress (open access)

Unmanned Vehicles for U.S. Naval Forces: Background and Issues for Congress

None
Date: May 31, 2006
Creator: O'Rourke, Ronald
Object Type: Report
System: The UNT Digital Library
The Value of Distributed Generation under Different TariffStructures (open access)

The Value of Distributed Generation under Different TariffStructures

Distributed generation (DG) may play a key role in a modern energy system because it can improve energy efficiency. Reductions in the energy bill, and therefore DG attractiveness, depend on the electricity tariff structure; a system created before widespread adoption of distributed generation. Tariffs have been designed to recover costs equitably amongst customers with similar consumption patterns. Recently, electric utilities began to question the equity of this electricity pricing structure for standby service. In particular, the utilities do not feel that DG customers are paying their fair share of transmission and distribution costs - traditionally recovered through a volumetric($/kWh) mechanism - under existing tariff structures. In response, new tariff structures with higher fixed costs for DG have been implemented in New York and in California. This work analyzes the effects of different electricity tariff structures on DG adoption. First, the effects of the new standby tariffs in New York are analyzed in different regions. Next generalized tariffs are constructed, and the sensitivity to varying levels of the volumetric and the demand ($/kW, i.e. maximum rate) charge component are analyzed on New York's standard and standby tariff as well as California's standby tariff. As expected, DG profitability is reduced with standby …
Date: May 31, 2006
Creator: Firestone, Ryan; Magnus Maribu, Karl & Marnay, Chris
Object Type: Article
System: The UNT Digital Library
Veterans’ Medical Care: FY2007 Appropriations (open access)

Veterans’ Medical Care: FY2007 Appropriations

None
Date: May 31, 2006
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Where Water is Oxidized to Dioxygen: Structure of thePhotosynthetic Mn4Ca Cluster (open access)

Where Water is Oxidized to Dioxygen: Structure of thePhotosynthetic Mn4Ca Cluster

Oxidation of water to dioxygen is catalyzed withinphotosystem II (PSII) by a Mn4Ca cluster, the structure of which remainselusive. Polarized extended X-ray absorption fine structure (EXAFS)measurements on PSII single crystals constrain the Mn4Ca cluster geometryto a set of three similar high-resolution structures. Combining polarizedEXAFS and X-ray diffraction data, the cluster was placed within PSIItaking into account the overall trend of the electron density of themetal site and the putative ligands. The structure of the cluster fromthe present study is unlike either the 3.0 or 3.5 Angstrom resolutionX-ray structures, and other previously proposed models.
Date: May 31, 2006
Creator: Yano, Junko; Kern, Jan; Sauer, Kenneth; Latimer, Matthew J.; Pushkar, Yulia; Biesiadka, Jacek et al.
Object Type: Article
System: The UNT Digital Library
X-ray Digital Radiography and Computed Tomography of ICF and HEDP Materials, Subassemblies and Targets (open access)

X-ray Digital Radiography and Computed Tomography of ICF and HEDP Materials, Subassemblies and Targets

Inertial confinement fusion (ICF) and high energy density physics (HEDP) research are being conducted at large laser facilities, such as the University of Rochester's Laboratory for Laser Energetics OMEGA facility and the Lawrence Livermore National Laboratory's (LLNL) National Ignition Facility (NIF). At such facilities, millimeter-sized targets with micrometer structures are studied in a variety of hydrodynamic, radiation transport, equation-of-state, inertial confinement fusion and high-energy density experiments. The extreme temperatures and pressures achieved in these experiments make the results susceptible to imperfections in the fabricated targets. Targets include materials varying widely in composition ({approx}3 < Z < {approx}82), density ({approx}0.03 to {approx}20 g/cm{sup 3}), geometry (planar to spherical) and embedded structures (joints to subassemblies). Fabricating these targets with structures to the tolerances required is a challenging engineering problem the ICF and HEDP community are currently undertaking. Nondestructive characterization (NDC) provides a valuable tool in material selection, component inspection, and the final pre-shot assemblies inspection. X-rays are a key method used to NDC these targets. In this paper we discuss X-ray attenuation, X-ray phase effects, and the X-ray system used, its performance and application to characterize low-temperature Raleigh-Taylor and non-cryogenic double-shell targets.
Date: May 31, 2006
Creator: Brown, W. D. & Martz, H. E., Jr.
Object Type: Article
System: The UNT Digital Library