Structural and Morphological Properties of Carbon Supports: Effect on Catalyst Degradation (open access)

Structural and Morphological Properties of Carbon Supports: Effect on Catalyst Degradation

The object of this work was to identify correlations between performance losses of Pt electrocatalysts on carbon support materials and the chemical and morphological parameters that describe them. Accelerated stress testing, with an upper potential of 1.2 V, was used to monitor changes to cathode properties, including kinetic performance and effective platinum surface area losses. The structure and chemical compositions were studied using X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy coupled with Digital Image Processing. As this is an ongoing study, it is difficult to draw firm conclusions, though a trend between support surface area overall performance loss was found to exist.
Date: July 1, 2010
Creator: Patel, Anant; Artyushkova, Kateryna; Atanassov, Plamen; Young, Alan; Dutta, Monica; Ahmad, Zaid et al.
Object Type: Article
System: The UNT Digital Library
Analysis of biostimulated microbial communities from two field experiments reveals temporal and spatial differences in proteome profiles (open access)

Analysis of biostimulated microbial communities from two field experiments reveals temporal and spatial differences in proteome profiles

Stimulated by an acetate-amendment field experiment conducted in 2007, anaerobic microbial populations in the aquifer at the Rifle Integrated Field Research Challenge site in Colorado reduced mobile U(VI) to insoluble U(IV). During this experiment, planktonic biomass was sampled at various time points to quantitatively evaluate proteomes. In 2008, an acetate-amended field experiment was again conducted in a similar manner to the 2007 experiment. As there was no comprehensive metagenome sequence available for use in proteomics analysis, we systematically evaluated 12 different organism genome sequences to generate sets of aggregate genomes, or “pseudo-metagenomes”, for supplying relative quantitative peptide and protein identifications. Proteomics results support previous observations of the dominance of Geobacteraceae during biostimulation using acetate as sole electron donor, and revealed a shift from an early stage of iron reduction to a late stage of iron reduction. Additionally, a shift from iron reduction to sulfate reduction was indicated by changes in the contribution of proteome information contributed by different organism genome sequences within the aggregate set. In addition, the comparison of proteome measurements made between the 2007 field experiment and 2008 field experiment revealed differences in proteome profiles. These differences may be the result of alterations in abundance and population structure …
Date: July 15, 2010
Creator: Callister, S. J.; Wilkins, M. J.; Nicora, C. D.; Williams, K. H.; Banfield, J. F.; VerBerkmoes, N. C. et al.
Object Type: Article
System: The UNT Digital Library
Methane hydrate distribution from prolonged and repeated formation in natural and compacted sand samples: X-ray CT observations (open access)

Methane hydrate distribution from prolonged and repeated formation in natural and compacted sand samples: X-ray CT observations

To study physical properties of methane gas hydrate-bearing sediments, it is necessary to synthesize laboratory samples due to the limited availability of cores from natural deposits. X-ray computed tomography (CT) and other observations have shown gas hydrate to occur in a number of morphologies over a variety of sediment types. To aid in understanding formation and growth patterns of hydrate in sediments, methane hydrate was repeatedly formed in laboratory-packed sand samples and in a natural sediment core from the Mount Elbert Stratigraphic Test Well. CT scanning was performed during hydrate formation and decomposition steps, and periodically while the hydrate samples remained under stable conditions for up to 60 days. The investigation revealed the impact of water saturation on location and morphology of hydrate in both laboratory and natural sediments during repeated hydrate formations. Significant redistribution of hydrate and water in the samples was observed over both the short and long term.
Date: July 1, 2010
Creator: Rees, E.V.L.; Kneafsey, T.J. & Seol, Y.
Object Type: Article
System: The UNT Digital Library
Cleanroom Energy Efficiency: Metrics and Benchmarks (open access)

Cleanroom Energy Efficiency: Metrics and Benchmarks

Cleanrooms are among the most energy-intensive types of facilities. This is primarily due to the cleanliness requirements that result in high airflow rates and system static pressures, as well as process requirements that result in high cooling loads. Various studies have shown that there is a wide range of cleanroom energy efficiencies and that facility managers may not be aware of how energy efficient their cleanroom facility can be relative to other cleanroom facilities with the same cleanliness requirements. Metrics and benchmarks are an effective way to compare one facility to another and to track the performance of a given facility over time. This article presents the key metrics and benchmarks that facility managers can use to assess, track, and manage their cleanroom energy efficiency or to set energy efficiency targets for new construction. These include system-level metrics such as air change rates, air handling W/cfm, and filter pressure drops. Operational data are presented from over 20 different cleanrooms that were benchmarked with these metrics and that are part of the cleanroom benchmark dataset maintained by Lawrence Berkeley National Laboratory (LBNL). Overall production efficiency metrics for cleanrooms in 28 semiconductor manufacturing facilities in the United States and recorded in the …
Date: July 7, 2010
Creator: Initiative, International SEMATECH Manufacturing; Mathew, Paul A.; Tschudi, William; Sartor, Dale & Beasley, James
Object Type: Article
System: The UNT Digital Library
Statics and Dynamics of Dimensionally and Spatially Constrained Oxides. Summary Progress Report Submitted to Department of Energy Basic Energy Science Division. Division of Materials Science & Engineering. (open access)

Statics and Dynamics of Dimensionally and Spatially Constrained Oxides. Summary Progress Report Submitted to Department of Energy Basic Energy Science Division. Division of Materials Science & Engineering.

Work is reported on nanopatterning of ceramic oxides; microstructure tailoring, control and versatility of nanopatterned oxides; and characterization and localized properties of nanopatterned oxides.
Date: July 31, 2010
Creator: Dravid, Vinayak P.
Object Type: Report
System: The UNT Digital Library
FY09 recycling opportunity assessment for Sandia National Laboratories/New Mexico. (open access)

FY09 recycling opportunity assessment for Sandia National Laboratories/New Mexico.

This Recycling Opportunity Assessment (ROA) is a revision and expansion of the FY04 ROA. The original 16 materials are updated through FY08, and then 56 material streams are examined through FY09 with action items for ongoing improvement listed for most. In addition to expanding the list of solid waste materials examined, two new sections have been added to cover hazardous waste materials. Appendices include energy equivalencies of materials recycled, trends and recycle data, and summary tables of high, medium, and low priority action items.
Date: July 1, 2010
Creator: McCord, Samuel Adam
Object Type: Report
System: The UNT Digital Library
Ice Formation in Gas-Diffusion Layers (open access)

Ice Formation in Gas-Diffusion Layers

Under sub-freezing conditions, ice forms in the gas-diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) drastically reducing cell performance. Although a number of strategies exist to prevent ice formation, there is little fundamental understanding of the mechanisms of freezing within PEMFC components. Differential scanning calorimetry (DSC) is used to elucidate the effects of hydrophobicity (Teflon® loading) and water saturation on the rate of ice formation within three commercial GDLs. We find that as the Teflon® loading increases, the crystallization temperature decreases due to a change in internal ice/substrate contact angle, as well as the attainable level of water saturation. Classical nucleation theory predicts the correct trend in freezing temperature with Teflon® loading.
Date: July 10, 2010
Creator: Dursch, Thomas; Radke, Clayton J. & Weber, Adam Z.
Object Type: Article
System: The UNT Digital Library
On a Pioneering Polymer Electrolyte Fuel Cell Model (open access)

On a Pioneering Polymer Electrolyte Fuel Cell Model

"Polymer Electrolyte Fuel Cell Model" is a seminal work that continues to form the basis for modern modeling efforts, especially models concerning the membrane and its behavior at the continuum level. The paper is complete with experimental data, modeling equations, model validation, and optimization scenarios. While the treatment of the underlying phenomena is limited to isothermal, single-phase conditions, and one-dimensional flow, it represents the key interactions within the membrane at the center of the PEFC. It focuses on analyzing the water balance within the cell and clearly demonstrates the complex interactions of water diffusion and electro-osmotic flux. Cell-level and system-level water balance are key to the development of efficient PEFCs going forward, particularly as researchers address the need to simplify humidification and recycle configurations while increasing the operating temperature of the stack to minimize radiator requirements.
Date: July 7, 2010
Creator: Weber, Adam Z. & Meyers, Jeremy P.
Object Type: Report
System: The UNT Digital Library
Transcription Factors Expressed in Lateral Organ Boundaries: Identification of Downstream Targets (open access)

Transcription Factors Expressed in Lateral Organ Boundaries: Identification of Downstream Targets

The processes of lateral organ initiation and patterning are central to the generation of mature plant form. Characterization of the molecular mechanisms underlying these processes is essential to our understanding of plant development. Communication between the shoot apical meristem and initiating organ primordia is important both for functioning of the meristem and for proper organ patterning, and very little is known about this process. In particular, the boundary between meristem and leaf is emerging as a critical region that is important for SAM maintenance and regulation of organogenesis. The goal of this project was to characterize three boundary-expressed genes that encode predicted transcription factors. Specifically, we have studied LATERAL ORGAN BOUNDARIES (LOB), LATERAL ORGAN FUSION1 (LOF1), and LATERAL ORGAN FUSION2 (LOF2). LOB encodes the founding member of the LOB-DOMAIN (LBD) plant-specific DNA binding transcription factor family and LOF1 and LOF2 encode paralogous MYB-domain transcription factors. We characterized the genetic relationship between these three genes and other boundary and meristem genes. We also used an ectopic inducible expression system to identify direct targets of LOB.
Date: July 12, 2010
Creator: Springer, Patricia S.
Object Type: Report
System: The UNT Digital Library
Instrumented Pipeline Initiative (open access)

Instrumented Pipeline Initiative

This report summarizes technical progress achieved during the cooperative agreement between Concurrent Technologies Corporation (CTC) and U.S. Department of Energy to address the need for a for low-cost monitoring and inspection sensor system as identified in the Department of Energy (DOE) National Gas Infrastructure Research & Development (R&D) Delivery Reliability Program Roadmap.. The Instrumented Pipeline Initiative (IPI) achieved the objective by researching technologies for the monitoring of pipeline delivery integrity, through a ubiquitous network of sensors and controllers to detect and diagnose incipient defects, leaks, and failures. This report is organized by tasks as detailed in the Statement of Project Objectives (SOPO). The sections all state the objective and approach before detailing results of work.
Date: July 31, 2010
Creator: Piro, Thomas & Ream, Michael
Object Type: Report
System: The UNT Digital Library
Full multiple scattering analysis of XANES at the Cd L3 and O K edges in CdO films combined with a soft-x-ray emission investigation (open access)

Full multiple scattering analysis of XANES at the Cd L3 and O K edges in CdO films combined with a soft-x-ray emission investigation

X-ray absorption near edge structure (XANES) at the cadmium L3 and oxygen K edges for CdO thin films grown by pulsed laser deposition method, is interpreted within the real-space multiple scattering formalism, FEFF code. The features in the experimental spectra are well reproduced by calculations for a cluster of about six and ten coordination shells around the absorber for L3 edge of Cd and K edge of O, respectively. The calculated projected electronic density of states is found to be in good agreement with unoccupied electronic states in experimental data and allows to conclude that the orbital character of the lowest energy of the conductive band is Cd-5s-O-2p. The charge transfer has been quantified and not purely ionic bonding has been found. Combined XANES and resonant inelastic x-ray scattering measurements allow us to determine the direct and indirect band gap of investigated CdO films to be {approx}2.4-eV and {approx}0.9-eV, respectively.
Date: July 5, 2010
Creator: Demchenko, I. N.; Denlinger, J. D.; Chernyshova, M.; Yu, K. M.; Speaks, D. T.; Olalde-Velasco, P. et al.
Object Type: Article
System: The UNT Digital Library
Liquid Fuel From Bacteria: Engineering Ralstonia eutropha for Production of Isobutanol (IBT) Motor Fuel from CO2, Hydrogen, and Oxygen (open access)

Liquid Fuel From Bacteria: Engineering Ralstonia eutropha for Production of Isobutanol (IBT) Motor Fuel from CO2, Hydrogen, and Oxygen

Electrofuels Project: MIT is using solar-derived hydrogen and common soil bacteria called Ralstonia eutropha to turn carbon dioxide (CO2) directly into biofuel. This bacteria already has the natural ability to use hydrogen and CO2 for growth. MIT is engineering the bacteria to use hydrogen to convert CO2 directly into liquid transportation fuels. Hydrogen is a flammable gas, so the MIT team is building an innovative reactor system that will safely house the bacteria and gas mixture during the fuel-creation process. The system will pump in precise mixtures of hydrogen, oxygen, and CO2, and the online fuel-recovery system will continuously capture and remove the biofuel product.
Date: July 15, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Natural Oil Production from Microorganisms: Bioprocess and Microbe Engineering for Total Carbon Utilization in Biofuel Production (open access)

Natural Oil Production from Microorganisms: Bioprocess and Microbe Engineering for Total Carbon Utilization in Biofuel Production

Electrofuels Project: MIT is using carbon dioxide (CO2) and hydrogen generated from electricity to produce natural oils that can be upgraded to hydrocarbon fuels. MIT has designed a 2-stage biofuel production system. In the first stage, hydrogen and CO2 are fed to a microorganism capable of converting these feedstocks to a 2-carbon compound called acetate. In the second stage, acetate is delivered to a different microorganism that can use the acetate to grow and produce oil. The oil can be removed from the reactor tank and chemically converted to various hydrocarbons. The electricity for the process could be supplied from novel means currently in development, or more proven methods such as the combustion of municipal waste, which would also generate the required CO2 and enhance the overall efficiency of MIT’s biofuel-production system.
Date: July 15, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Mechanical Stability Study (open access)

Mechanical Stability Study

None
Date: July 2010
Creator: Krahn, Elizabeth O.; Hebden, Andrew S.; Vandegrift, George F.; Chung, Pei-Lun & Wang, Nien-Hwa Linda
Object Type: Report
System: The UNT Digital Library
Liquid Fuel From Renewable Electricity and Bacteria: Electro-Autotrophic Synthesis of Higher Alcohols (open access)

Liquid Fuel From Renewable Electricity and Bacteria: Electro-Autotrophic Synthesis of Higher Alcohols

Electrofuels Project: UCLA is utilizing renewable electricity to power direct liquid fuel production in genetically engineered Ralstonia eutropha bacteria. UCLA is using renewable electricity to convert carbon dioxide into formic acid, a liquid soluble compound that delivers both carbon and energy to the bacteria. The bacteria are genetically engineered to convert the formic acid into liquid fuel—in this case alcohols such as butanol. The electricity required for the process can be generated from sunlight, wind, or other renewable energy sources. In fact, UCLA’s electricity-to-fuel system could be a more efficient way to utilize these renewable energy sources considering the energy density of liquid fuel is much higher than the energy density of other renewable energy storage options, such as batteries.
Date: July 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Rechargeable Lithium-Air Batteries: Development of Ultra High Specific Energy Rechargeable Lithium-Air Batteries Based on Protected Lithium Metal Electrodes (open access)

Rechargeable Lithium-Air Batteries: Development of Ultra High Specific Energy Rechargeable Lithium-Air Batteries Based on Protected Lithium Metal Electrodes

BEEST Project: PolyPlus is developing the world’s first commercially available rechargeable lithium-air (Li-Air) battery. Li-Air batteries are better than the Li-Ion batteries used in most EVs today because they breathe in air from the atmosphere for use as an active material in the battery, which greatly decreases its weight. Li-Air batteries also store nearly 700% as much energy as traditional Li-Ion batteries. A lighter battery would improve the range of EVs dramatically. Polyplus is on track to making a critical breakthrough: the first manufacturable protective membrane between its lithium–based negative electrode and the reaction chamber where it reacts with oxygen from the air. This gives the battery the unique ability to recharge by moving lithium in and out of the battery’s reaction chamber for storage until the battery needs to discharge once again. Until now, engineers had been unable to create the complex packaging and air-breathing components required to turn Li-Air batteries into rechargeable systems.
Date: July 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Hurricane Intensity, Sea Surface Temperature, and Stochastic Variation (open access)

Hurricane Intensity, Sea Surface Temperature, and Stochastic Variation

None
Date: July 14, 2010
Creator: Bogen, K. T.; Fischer, L. E. & Jones, E. D.
Object Type: Article
System: The UNT Digital Library
Chip-Scale Nanofabrication of Single Spins and Spin Arrays in Diamond (open access)

Chip-Scale Nanofabrication of Single Spins and Spin Arrays in Diamond

We demonstrate a technique to nanofabricate nitrogen vacancy (NV) centers in diamond based on broad-beam nitrogen implantation through apertures in electron beam lithography resist. This method enables high-throughput nanofabrication of single NV centers on sub-100-nm length scales. Secondary ion mass spectroscopy measurements facilitate depth profiling of the implanted nitrogen to provide three-dimensional characterization of the NV center spatial distribution. Measurements of NV center coherence with on-chip coplanar waveguides suggest a pathway for incorporating this scalable nanofabrication technique in future quantum applications.
Date: July 2, 2010
Creator: Toyli, David M.; Weis, Christoph D.; Fuchs, D.; Schenkel, Thomas & Awschalom, David D.
Object Type: Article
System: The UNT Digital Library
New Electrode Manufacturing Process Equipment: Novel High Energy Density Lithium-Ion Cell Designs via Innovative Manufacturing Process Modules for Cathode and Integrated Separator (open access)

New Electrode Manufacturing Process Equipment: Novel High Energy Density Lithium-Ion Cell Designs via Innovative Manufacturing Process Modules for Cathode and Integrated Separator

BEEST Project: Applied Materials is developing new tools for manufacturing Li-Ion batteries that could dramatically increase their performance. Traditionally, the positive and negative terminals of Li-Ion batteries are mixed with glue-like materials called binders, pressed onto electrodes, and then physically kept apart by winding a polymer mesh material between them called a separator. With the Applied Materials system, many of these manually intensive processes will be replaced by next generation coating technology to apply each component. This process will improve product reliability and performance of the cells at a fraction of the current cost. These novel manufacturing techniques will also increase the energy density of the battery and reduce the size of several of the battery’s components to free up more space within the cell for storage.
Date: July 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Liquid Fuel from Heat-Loving Microorganisms: H2-Dependent Conversion of CO2 to Liquid Electrofuels by Extremely Thermophilic Archaea (open access)

Liquid Fuel from Heat-Loving Microorganisms: H2-Dependent Conversion of CO2 to Liquid Electrofuels by Extremely Thermophilic Archaea

Electrofuels Project: NC State is working with the University of Georgia to create Electrofuels from primitive organisms called extremophiles that evolved before photosynthetic organisms and live in extreme, hot water environments with temperatures ranging from 167-212 degrees Fahrenheit The team is genetically engineering these microorganisms so they can use hydrogen to turn carbon dioxide directly into alcohol-based fuels. High temperatures are required to distill the biofuels from the water where the organisms live, but the heat-tolerant organisms will continue to thrive even as the biofuels are being distilled—making the fuel-production process more efficient. The microorganisms don’t require light, so they can be grown anywhere—inside a dark reactor or even in an underground facility.
Date: July 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Pair-distribution function analysis of the structural valence transition in Cp{sub 2}{sup *}Yb(4,4'-Me{sub 2}-bipy) (open access)

Pair-distribution function analysis of the structural valence transition in Cp{sub 2}{sup *}Yb(4,4'-Me{sub 2}-bipy)

The Cp{sup ∗}{sub 2} Yb(L) class of compounds, where Cp{sup ∗}=pentamethylcyclopentadienyl = C{sub 5}Me{sub 5} and L is either a 1,4-diazabutadiene or bipy = 2,2′-bipyridine related ligand, have provided excellent analogies to the Kondo state on the nanoscale. Cp{sup ∗}{sub 2} Yb(4,4′-Me{sub 2}-bipy) furthers this analogy by demonstrating a valence transition as the sample is cooled below 200 K. Here, pair-distribution function (PDF) analysis of x-ray powder diffraction data demonstrate that the Cp{sup ∗}{sub 2}Yb(4,4′-Me{sub 2}-bipy) molecule is virtually unchanged through the valence transition. However, the molecule’s stacking arrangement is altered through the valence transition.
Date: July 20, 2010
Creator: Booth, C H; Bauer, E D; Bozin, E S; Billinge, S J L & Walter, M D
Object Type: Article
System: The UNT Digital Library
Liquid Fuel From Microbial Communities: Electroalcoholgenesis: Bioelectrochemical Reduction of CO2 to Butanol (open access)

Liquid Fuel From Microbial Communities: Electroalcoholgenesis: Bioelectrochemical Reduction of CO2 to Butanol

Electrofuels Project: MUSC is developing an engineered system to create liquid fuels from communities of interdependent microorganisms. MUSC is first pumping carbon dioxide (CO2) and renewable sources of electricity into a battery-like cell. A community of microorganisms uses the electricity to convert the CO2 into hydrogen. That hydrogen is then consumed by another community of microorganisms living in the same system. These new microorganisms convert the hydrogen into acetate, which in turn feed yet another community of microorganisms. This last community of microorganisms uses the acetate to produce a liquid biofuel called butanol. Similar interdependent microbial communities can be found in some natural environments, but they’ve never been coupled together in an engineered cell to produce liquid fuels. MUSC is working to triple the amount of butanol that can be produced in its system and to reduce the overall cost of the process.
Date: July 1, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Existing and Past Methods of Test and Rating Standards Related to Integrated Heat Pump Technologies (open access)

Existing and Past Methods of Test and Rating Standards Related to Integrated Heat Pump Technologies

This report evaluates existing and past US methods of test and rating standards related to electrically operated air, water, and ground source air conditioners and heat pumps, 65,000 Btu/hr and under in capacity, that potentiality incorporate a potable water heating function. Two AHRI (formerly ARI) standards and three DOE waivers were identified as directly related. Six other AHRI standards related to the test and rating of base units were identified as of interest, as they would form the basis of any new comprehensive test procedure. Numerous other AHRI and ASHRAE component test standards were also identified as perhaps being of help in developing a comprehensive test procedure.
Date: July 1, 2010
Creator: Reedy, Wayne R.
Object Type: Report
System: The UNT Digital Library
What Can China Do? China's Best Alternative Outcome for Energy Efficiency and CO2 Emissions (open access)

What Can China Do? China's Best Alternative Outcome for Energy Efficiency and CO2 Emissions

After rapid growth in economic development and energy demand over the last three decades, China has undertaken energy efficiency improvement efforts to reduce its energy intensity under the 11th Five Year Plan (FYP). Since becoming the world's largest annual CO{sub 2} emitter in 2007, China has set reduction targets for energy and carbon intensities and committed to meeting 15% of its total 2020 energy demand with non-fossil fuel. Despite having achieved important savings in 11th FYP efficiency programs, rising per capita income and the continued economic importance of trade will drive demand for transport activity and fuel use. At the same time, an increasingly 'electrified' economy will drive rapid power demand growth. Greater analysis is therefore needed to understand the underlying drivers, possible trajectories and mitigation potential in the growing industrial, transport and power sectors. This study uses scenario analysis to understand the likely trajectory of China's energy and carbon emissions to 2030 in light of the current and planned portfolio of programs, policies and technology development and ongoing urbanization and demographic trends. It evaluates the potential impacts of alternative transportation and power sector development using two key scenarios, Continued Improvement Scenario (CIS) and Accelerated Improvement Scenario (AIS). CIS represents …
Date: July 1, 2010
Creator: G. Fridley, David; Zheng, Nina & T. Aden, Nathaniel
Object Type: Report
System: The UNT Digital Library