Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry (open access)

Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry

For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI earth system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous …
Date: May 15, 2010
Creator: Berryman, J.G.
Object Type: Article
System: The UNT Digital Library
ARM Climate Research Facility Instrumentation Status and Information April 2010 (open access)

ARM Climate Research Facility Instrumentation Status and Information April 2010

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: May 15, 2010
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Design and Synthesis of Mixed Oxides Nanoparticles for Biofuel Applications (open access)

Design and Synthesis of Mixed Oxides Nanoparticles for Biofuel Applications

The work in this dissertation presents the synthesis of two mixed metal oxides for biofuel applications and NMR characterization of silica materials. In the chapter 2, high catalytic efficiency of calcium silicate is synthesized for transesterfication of soybean oil to biodisels. Chapter 3 describes the synthesis of a new Rh based catalyst on mesoporous manganese oxides. The new catalyst is found to have higher activity and selectivity towards ethanol. Chapter 4 demonstrates the applications of solid-state Si NMR in the silica materials.
Date: May 15, 2010
Creator: Chen, Senniang
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Value and Technology Assessment to Enhance the Business Case for the CERTS Microgrid (open access)

Value and Technology Assessment to Enhance the Business Case for the CERTS Microgrid

The CERTS Microgrid concept is an advanced approach for enabling integration of, in principle, an unlimited quantity of distributed energy resources into the electricity grid. A key feature of a microgrid, is its ability, during a utility grid disturbance, to separate and isolate itself from the utility seamlessly with no disruption to the loads within the microgrid (including no reduction in power quality). Then, when the utility grid returns to normal, the microgrid automatically resynchronizes and reconnects itself to the grid, in an equally seamless fashion. What is unique about the CERTS Microgrid is that it can provide this technically challenging functionality without extensive (i.e., expensive) custom engineering. In addition, the design of the CERTS Microgrid also provides high system reliability and great flexibility in the placement of distributed generation within the microgrid. The CERTS Microgrid offers these functionalities at much lower costs than traditional approaches by incorporating peer-to-peer and plug-and-play concepts for each component within the Microgrid. The predecessor to the current project involved the construction of and completion of initial testing using the world's first, full-scale, inverter-based, distributed generation test bed. The project demonstrated three advanced techniques, collectively referred to as the CERTS Microgrid concept, which collectively significantly …
Date: May 15, 2010
Creator: Lasseter, Robert & Eto, Joe
Object Type: Report
System: The UNT Digital Library