Development & Optimization of Materials and Processes for a Cost Effective Photoelectrochemical Hydrogen Production System (open access)

Development & Optimization of Materials and Processes for a Cost Effective Photoelectrochemical Hydrogen Production System

The overall project objective was to apply high throughput experimentation and combinatorial methods together with novel syntheses to discover and optimize efficient, practical, and economically sustainable materials for photoelectrochemical production of bulk hydrogen from water. Automated electrochemical synthesis and photoelectrochemical screening systems were designed and constructed and used to study a variety of new photoelectrocatalytic materials. We evaluated photocatalytic performance in the dark and under illumination with or without applied bias in a high-throughput manner and did detailed evaluation on many materials. Significant attention was given to -Fe2O3 based semiconductor materials and thin films with different dopants were synthesized by co-electrodeposition techniques. Approximately 30 dopants including Al, Zn, Cu, Ni, Co, Cr, Mo, Ti, Pt, etc. were investigated. Hematite thin films doped with Al, Ti, Pt, Cr, and Mo exhibited significant improvements in efficiency for photoelectrochemical water splitting compared with undoped hematite. In several cases we collaborated with theorists who used density functional theory to help explain performance trends and suggest new materials. The best materials were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visual spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS). The photoelectrocatalytic performance of the thin films was evaluated and their incident photon
Date: January 17, 2011
Creator: McFarland, Eric W.
System: The UNT Digital Library
Field Campaign Guidelines (ARM Climate Research Facility) (open access)

Field Campaign Guidelines (ARM Climate Research Facility)

The purpose of this document is to establish a common set of guidelines for the Atmospheric Radiation Measurement (ARM) Climate Research Facility for planning, executing, and closing out field campaigns. The steps that guide individual field campaigns are described in the Field Campaign Tracking database tool and are tailored to meet the scope of each specific field campaign.
Date: January 17, 2011
Creator: Voyles, JW
System: The UNT Digital Library
Accelerating Innovation: How Nuclear Physics Benefits Us All (open access)

Accelerating Innovation: How Nuclear Physics Benefits Us All

From fighting cancer to assuring food is safe to protecting our borders, nuclear physics impacts the lives of people around the globe every day. In learning about the nucleus of the atom and the forces that govern it, scientists develop a depth of knowledge, techniques and remarkable research tools that can be used to develop a variety of often unexpected, practical applications. These applications include devices and technologies for medical diagnostics and therapy, energy production and exploration, safety and national security, and for the analysis of materials and environmental contaminants. This brochure by the Office of Nuclear Physics of the USDOE Office of Science discusses nuclear physics and ways in which its applications fuel our economic vitality, and make the world and our lives safer and healthier.
Date: January 1, 2011
Creator: unknown
System: The UNT Digital Library
Voronoi Tessellations and Their Application to Climate and Global Modeling (open access)

Voronoi Tessellations and Their Application to Climate and Global Modeling

We review the use of Voronoi tessellations for grid generation, especially on the whole sphere or in regions on the sphere. Voronoi tessellations and the corresponding Delaunay tessellations in regions and surfaces on Euclidean space are defined and properties they possess that make them well-suited for grid generation purposes are discussed, as are algorithms for their construction. This is followed by a more detailed look at one very special type of Voronoi tessellation, the centroidal Voronoi tessellation (CVT). After defining them, discussing some of their properties, and presenting algorithms for their construction, we illustrate the use of CVTs for producing both quasi-uniform and variable resolution meshes in the plane and on the sphere. Finally, we briefly discuss the computational solution of model equations based on CVTs on the sphere.
Date: January 1, 2011
Creator: Ju, Lili; Ringler, Todd & Gunzburger, Max
System: The UNT Digital Library
36th Annual International Conference on Infrared Millimeter and Terahertz Waves (open access)

36th Annual International Conference on Infrared Millimeter and Terahertz Waves

The Major Topic List of the 2011 conference featured a category entitled “IR, millimeter-wave, and THz spectroscopy,” another entitled “Gyro- Oscillators and Amplifiers, Plasma Diagnostics,” and a third called “Free Electron Lasers and Synchrotron Radiation.” Topical areas of interest to meeting participants include millimeter-wave electronics, high-power sources, high-frequency communications systems, and terahertz sensing and imaging, all of which are prominent in the research portfolios of the DOE. The development and study of new materials, components, and systems for use in the IR, THz, and MMW regions of the spectrum are of significant interest as well. a series of technical sessions were organized on the following topics:  terahertz metamaterials and plasmonics;  imaging techniques and applications;  graphene spectroscopy;  waveguide concepts;  gyrotron science and technology;  ultrafast terahertz measurements; and  quantum cascade lasers.
Date: January 1, 2011
Creator: Mittleman, Daniel M.
System: The UNT Digital Library