Biofuel alternatives to ethanol: pumping the microbial well (open access)

Biofuel alternatives to ethanol: pumping the microbial well

Engineered microorganisms are currently used for the production of food products, pharmaceuticals, ethanol fuel and more. Even so, the enormous potential of this technology has yet to be fully exploited. The need for sustainable sources of transportation fuels has gener-ated a tremendous interest in technologies that enable biofuel production. Decades of work have produced a considerable knowledge-base for the physiology and pathway engineering of microbes, making microbial engineering an ideal strategy for producing biofuel. Although ethanol currently dominates the biofuel mar-ket, some of its inherent physical properties make it a less than ideal product. To highlight additional options, we review advances in microbial engineering for the production of other potential fuel molecules, using a variety of biosynthetic pathways.
Date: December 2, 2009
Creator: Fortman, J. L.; Chhabra, Swapnil; Mukhopadhyay, Aindrila; Chou, Howard; Lee, Taek Soon; Steen, Eric et al.
Object Type: Article
System: The UNT Digital Library
Development of a Stochastic Inversion Tool To Optimize Agreement Between The Observed And Predicted Seismic Response To CO2 Injection/Migration in the Weyburn-Midale Project (open access)

Development of a Stochastic Inversion Tool To Optimize Agreement Between The Observed And Predicted Seismic Response To CO2 Injection/Migration in the Weyburn-Midale Project

During Phase 1 of the Weyburn Project (2000-2004), 4D reflection seismic data were used to map CO{sub 2} migration within the Midale reservoir, while an extensive fluid sampling program documented the geochemical evolution triggered by CO{sub 2}-brine-oil-mineral interactions. The aim of this task (3b.11) is to exploit these existing seismic and geochemical data sets, augmented by CO{sub 2}/H{sub 2}O injection and HC/H{sub 2}O production data toward optimizing the reservoir model and thereby improving site characterization and dependent predictions of long-term CO{sub 2} storage in the Weyburn-Midale reservoir. Our initial project activities have concentrated on developing a stochastic inversion method that will identify reservoir models that optimize agreement between the observed and predicted seismic response. This report describes the technical approach we have followed, the data that supports it, and associated implementation activities. The report fulfills deliverable D1 in the project's statement of work. Future deliverables will describe the development of the stochastic inversion tool that uses geochemical data to optimize the reservoir model.
Date: December 2, 2009
Creator: Ramirez, A. L.; Hao, Y.; White, D.; Carle, S.; Dyer, K.; Yang, X. et al.
Object Type: Report
System: The UNT Digital Library
The Impact of Wind Power Projects on Residential Property Values in the United States: A Multi-Site Hedonic Analysis (open access)

The Impact of Wind Power Projects on Residential Property Values in the United States: A Multi-Site Hedonic Analysis

With wind energy expanding rapidly in the U.S. and abroad, and with an increasing number of communities considering wind power development nearby, there is an urgent need to empirically investigate common community concerns about wind project development. The concern that property values will be adversely affected by wind energy facilities is commonly put forth by stakeholders. Although this concern is not unreasonable, given property value impacts that have been found near high voltage transmission lines and other electric generation facilities, the impacts of wind energy facilities on residential property values had not previously been investigated thoroughly. The present research collected data on almost 7,500 sales of singlefamily homes situated within 10 miles of 24 existing wind facilities in nine different U.S. states. The conclusions of the study are drawn from eight different hedonic pricing models, as well as both repeat sales and sales volume models. The various analyses are strongly consistent in that none of the models uncovers conclusive evidence of the existence of any widespread property value impacts that might be present in communities surrounding wind energy facilities. Specifically, neither the view of the wind facilities nor the distance of the home to those facilities is found to have …
Date: December 2, 2009
Creator: Hoen, Ben; Wiser, Ryan; Cappers, Peter; Thayer, Mark & Sethi, Gautam
Object Type: Report
System: The UNT Digital Library
Importance of systems biology in engineering microbes for biofuel production (open access)

Importance of systems biology in engineering microbes for biofuel production

Microorganisms have been rich sources for natural products, some of which have found use as fuels, commodity chemicals, specialty chemicals, polymers, and drugs, to name a few. The recent interest in production of transportation fuels from renewable resources has catalyzed numerous research endeavors that focus on developing microbial systems for production of such natural products. Eliminating bottlenecks in microbial metabolic pathways and alleviating the stresses due to production of these chemicals are crucial in the generation of robust and efficient production hosts. The use of systems-level studies makes it possible to comprehensively understand the impact of pathway engineering within the context of the entire host metabolism, to diagnose stresses due to product synthesis, and provides the rationale to cost-effectively engineer optimal industrial microorganisms.
Date: December 2, 2009
Creator: Mukhopadhyay, Aindrila; Redding, Alyssa M.; Rutherford, Becky J. & Keasling, Jay D.
Object Type: Article
System: The UNT Digital Library
Magnetic vortex dynamics on a picosecond timescale in a hexagonal permalloy pattern (open access)

Magnetic vortex dynamics on a picosecond timescale in a hexagonal permalloy pattern

We have observed a motion of magnetic vortex core in a hexagonal Permalloy pattern by means of Soft X-ray microscopy. Pump-probe stroboscopic observation on a picosecond timescale has been carried out after exciting a ground state vortex structure by an external field pulse of 1 ns duration. Vortex core is excited off from the center position of the hexagonal pattern but the analysis of the core trajectory reveals that the motion is nongyrotropic.
Date: December 2, 2009
Creator: Shim, J.-H.; Kim, D.-H.; Mesler, B.; Moon, J.-H.; Lee, K.-J.; Anderson, E. H. et al.
Object Type: Article
System: The UNT Digital Library
Metabolic engineering of microorganisms for biofuels production: from bugs to synthetic biology to fuels (open access)

Metabolic engineering of microorganisms for biofuels production: from bugs to synthetic biology to fuels

The ability to generate microorganisms that can produce biofuels similar to petroleum-based transportation fuels would allow the use of existing engines and infrastructure and would save an enormous amount of capital required for replacing the current infrastructure to accommodate biofuels that have properties significantly different from petroleum-based fuels. Several groups have demonstrated the feasibility of manipulating microbes to produce molecules similar to petroleum-derived products, albeit at relatively low productivity (e.g. maximum butanol production is around 20 g/L). For cost-effective production of biofuels, the fuel-producing hosts and pathways must be engineered and optimized. Advances in metabolic engineering and synthetic biology will provide new tools for metabolic engineers to better understand how to rewire the cell in order to create the desired phenotypes for the production of economically viable biofuels.
Date: December 2, 2009
Creator: Kuk Lee, Sung; Chou, Howard; Ham, Timothy S.; Soon Lee, Taek & Keasling, Jay D.
Object Type: Article
System: The UNT Digital Library
Neutron Capture Cross Sections from Surrogate Measurements (open access)

Neutron Capture Cross Sections from Surrogate Measurements

None
Date: December 2, 2009
Creator: Escher, J E; Dietrich, F S & Scielzo, N D
Object Type: Article
System: The UNT Digital Library
Ocean Thermal Plantships for Production of Ammonia as the Hydrogen Carrier. (open access)

Ocean Thermal Plantships for Production of Ammonia as the Hydrogen Carrier.

Conventional petroleum, natural gas, and coal are the primary sources of energy that have underpinned modern civilization. Their continued availability in the projected quantities required and the impacts of emission of greenhouse gases (GHGs) on the environment are issues at the forefront of world concerns. New primary sources of energy are being sought that would significantly reduce the emissions of GHGs. One such primary source that can help supply energy, water, and fertilizer without GHG emissions is available in the heretofore unexploited thermal gradients of the tropical oceans. The world's oceans are the largest natural collector and reservoir of solar energy. The potential of ocean energy is limitless for producing base-load electric power or ammonia as the hydrogen carrier and fresh water from seawater. However, until now, ocean energy has been virtually untapped. The general perception is that ocean thermal energy is limited to tropical countries. Therefore, the full potential of at-sea production of (1) ammonia as a hydrogen carrier and (2) desalinated water has not been adequately evaluated. Using ocean thermal plantships for the at-sea co-production of ammonia as a hydrogen carrier and desalinated water offer potential energy, environmental, and economic benefits that support the development of the technology. …
Date: December 2, 2009
Creator: Panchal, C.B.; Pandolfini, P. P.; Kumm, W. H.; Systems, Energy; Univ., Johns Hopkins & Arctic Energies, Ltd.
Object Type: Report
System: The UNT Digital Library
Optical manipulation of ultrafast electron and nuclear motion on metal surfaces (open access)

Optical manipulation of ultrafast electron and nuclear motion on metal surfaces

We study the unoccupied electronic structure and dynamics of chemisorbed atoms and molecules on metal surfaces by time resolved two-photon photoemission (TR-2PP). spectroscopy, low temperature scanning tunneling microscopy (LT-STM), and theory. Our research concerns simple atomic adsorbates such as alkali and alkaline earth atoms, which provide fundamentally important models for adsorbate-surface interactions, and more complex adsorbates such as fullerenes on noble metals, which illustrate emergent interfacial properties that derive from intrinsic molecular attributes, and moleculemolecule and molecule-surface interactions. Our goal is to understand how these interactions contribute to formation of the interfacial electronic structure, and how thus formed electronic properties affect interfacial phenomena of importance to energy transduction and storage. Moreover, we explore how the interfacial electronic excitation drives dynamical phenomena such as charge transfer and surface femtochemistry.
Date: December 2, 2009
Creator: Petek, Hrvoje
Object Type: Report
System: The UNT Digital Library
TANK FARMS OEPRATIONS RECOVERY ACT WASTE INITIATIVES (open access)

TANK FARMS OEPRATIONS RECOVERY ACT WASTE INITIATIVES

None
Date: December 2, 2009
Creator: DE, SWENSON
Object Type: Article
System: The UNT Digital Library
The Adoption of Advanced Fuel Cycle Technology Under a Single Repository Policy (open access)

The Adoption of Advanced Fuel Cycle Technology Under a Single Repository Policy

Develops the tools to investiage the hypothesis that the savings in repository space associated with the implementation of advanced nuclear fuel cycles can result in sufficient cost savings to offset the higher costs of those fuel cycles.
Date: November 2, 2009
Creator: Wilson, Paul
Object Type: Report
System: The UNT Digital Library
Age estimation in forensic sciences: Application of combined aspartic acid racemization and radiocarbon analysis (open access)

Age estimation in forensic sciences: Application of combined aspartic acid racemization and radiocarbon analysis

Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster, since the age at death, birth date and year of death, as well as gender, can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization has shown reproducible and more precise results. In this paper we analyze teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that above-ground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ({sup 14}C) which have been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel and ten of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R2=0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 0.6 {+-} 04 years. Aspartic acid racemization also showed …
Date: November 2, 2009
Creator: Alkass, K.; Buchholz, B. A.; Ohtani, S.; Yamamoto, T.; Druid, H. & Spalding, S. L.
Object Type: Article
System: The UNT Digital Library
Boron-Lined Neutron Detector Measurements (open access)

Boron-Lined Neutron Detector Measurements

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. Reported here are the results of tests of a newly designed boron-lined proportional counter option. This testing measured the neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Reuter Stokes.
Date: November 2, 2009
Creator: Lintereur, Azaree T.; Kouzes, Richard T.; Ely, James H.; Erikson, Luke E. & Siciliano, Edward R.
Object Type: Report
System: The UNT Digital Library
Critical Evaluation of the ISCCP Simulator Using Ground-Based Remote Sensing Data (open access)

Critical Evaluation of the ISCCP Simulator Using Ground-Based Remote Sensing Data

Given the known shortcomings in representing clouds in Global Climate Models (GCM) comparisons with observations are critical. The International Satellite Cloud Climatology Project (ISCCP) diagnostic products provide global descriptions of cloud top pressure and column optical depth that extends over multiple decades. The necessary limitations of the ISCCP retrieval algorithm require that before comparisons can be made between model output and ISCCP results the model output must be modified to simulate what ISCCP would diagnose under the simulated circumstances. We evaluate one component of the so-called ISCCP simulator in this study by comparing ISCCP and a similar algorithm with various long-term statistics derived from the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility ground-based remote sensors. We find that were a model to simulate the cloud radiative profile with the same accuracy as can be derived from the ARM data, then the likelihood of that occurrence being placed in the same cloud top pressure and optical depth bin as ISCCP of the 9 bins that have become standard ranges from 30% to 70% depending on optical depth. While the ISCCP simulator improved the agreement of cloud-top pressure between ground-based remote sensors and satellite observations, we find minor …
Date: November 2, 2009
Creator: Mace, G. G.; Houser, S.; Benson, S.; Klein, S. A. & Min, Q.
Object Type: Article
System: The UNT Digital Library
HRTEM Study of Oxide Nanoparticles in K3-ODS Ferritic Steel Developed for Radiation Tolerance (open access)

HRTEM Study of Oxide Nanoparticles in K3-ODS Ferritic Steel Developed for Radiation Tolerance

Crystal and interfacial structures of oxide nanoparticles and radiation damage in 16Cr-4.5Al-0.3Ti-2W-0.37 Y{sub 2}O{sub 3} ODS ferritic steel have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. Oxide nanoparticles with a complex-oxide core and an amorphous shell were frequently observed. The crystal structure of complex-oxide core is identified to be mainly monoclinic Y{sub 4}Al{sub 2}O{sub 9} (YAM) oxide compound. Orientation relationships between the oxide and the matrix are found to be dependent on the particle size. Large particles (> 20 nm) tend to be incoherent and have a spherical shape, whereas small particles (< 10 nm) tend to be coherent or semi-coherent and have a faceted interface. The observations of partially amorphous nanoparticles and multiple crystalline domains formed within a nanoparticle lead us to propose a three-stage mechanism to rationalize the formation of oxide nanoparticles containing core/shell structures in as-fabricated ODS steels. Effects of nanoparticle size and density on cavity formation induced by (Fe{sup 8+} + He{sup +}) dual-beam irradiation are briefly addressed.
Date: November 2, 2009
Creator: Hsiung, L; Fluss, M; Tumey, S; Kuntz, J; El-Dasher, B; Wall, M et al.
Object Type: Article
System: The UNT Digital Library
NDCX-II project commencing at LBNL (open access)

NDCX-II project commencing at LBNL

None
Date: November 2, 2009
Creator: Friedman, Alex & Kwan, Joe
Object Type: Article
System: The UNT Digital Library
Phase 1 Final Technical Report - MgB2 Synthesis for High Field Performance (open access)

Phase 1 Final Technical Report - MgB2 Synthesis for High Field Performance

Accelerator Technology Corp. (ATC) has successfully completed its Phase 1 effort to devel-op rf plasma torch synthesis of MgB2 superconducting powder. The overall objective is to de-velop a way to introduce homogeneous alloying of C and SiC impurities into phase-pure MgB2. Several groups have attained remarkable benefits from such alloying in raising the upper critical field Hc2 from ~14 T to ~30 T (bulk) and ~50 T (thin films). But no one has succeeded in pro-ducing that benefit homogeneously, so that current transport in a practical powder-in-tube (PIT) conductor is largely the same as without the alloying. ATC has conceived the possibility of attaining such homogeneity by passing aerosol suspen-sions of reactant powders through an rf plasma torch, with each reactant transported on a stream-line that heats it to an optimum temperature for the synthesis reaction. This procedure would uniquely access non-equilibrium kinetics for the synthesis reaction, and would provide the possi-bility to separately control the temperature and stoichiometry of each reactant as it enters the mixing region where synthesis occurs. It also facilitates the introduction of seed particles (e.g. nanoscale SiC) to dramatically enhance the rate of the synthesis reaction compared to gas-phase synthesis in rf plasma reported by …
Date: November 2, 2009
Creator: Bhatia, Mohit & McIntyre, Peter
Object Type: Report
System: The UNT Digital Library
Evaluation Of Automated Low-Field Nuclear Magnetic Resonance (NMR) Relaxometry For Analysis Of Silicone Polymers (open access)

Evaluation Of Automated Low-Field Nuclear Magnetic Resonance (NMR) Relaxometry For Analysis Of Silicone Polymers

Screening studies and Design of Experiments (DoE) were performed to evaluate measurement variation of a new, non-destructive Nuclear Magnetic Resonance (NMR) test system designed to assess age-induced degradation of Outer Pressure Pads (OPP). The test method and results from 54,275 measurements are described. A reduction in measurement error was obtained after metal support struts were replaced with plastic support struts adjacent to the front position of the test chamber. However, remaining interference and a lack of detecting any age-related degradation prevent the use of the NMR system as a non-destructive surveillance test for OPPs. A cursory evaluation of the system with cellular silicone samples obtained more uniform results with increased error as measurements approached the sample’s edge.
Date: October 2, 2009
Creator: Wilson, M. H.
Object Type: Report
System: The UNT Digital Library
A multi-channel gel electrophoresis and continuous fraction collection apparatus for high throughput protein separation and characterization (open access)

A multi-channel gel electrophoresis and continuous fraction collection apparatus for high throughput protein separation and characterization

To facilitate a direct interface between protein separation by PAGE and protein identification by mass spectrometry, we developed a multichannel system that continuously collects fractions as protein bands migrate off the bottom of gel electrophoresis columns. The device was constructed using several short linear gel columns, each of a different percent acrylamide, to achieve a separation power similar to that of a long gradient gel. A Counter Free-Flow elution technique then allows continuous and simultaneous fraction collection from multiple channels at low cost. We demonstrate that rapid, high-resolution separation of a complex protein mixture can be achieved on this system using SDS-PAGE. In a 2.5 h electrophoresis run, for example, each sample was separated and eluted into 48-96 fractions over a mass range of 10-150 kDa; sample recovery rates were 50percent or higher; each channel was loaded with up to 0.3 mg of protein in 0.4 mL; and a purified band was eluted in two to three fractions (200 L/fraction). Similar results were obtained when running native gel electrophoresis, but protein aggregation limited the loading capacity to about 50 g per channel and reduced resolution.
Date: October 2, 2009
Creator: Choi, Megan; Nordmeyer, Robert A.; Cornell, Earl; Dong, Ming; Biggin, Mark D. & Jin, Jian
Object Type: Article
System: The UNT Digital Library
On Skew-Symmetric Splitting and Entropy Conservation Schemes for the Euler Equations (open access)

On Skew-Symmetric Splitting and Entropy Conservation Schemes for the Euler Equations

None
Date: October 2, 2009
Creator: Sjogreen, B & Yee, H C
Object Type: Article
System: The UNT Digital Library
Production of ra225 Precursor for ac225/bi213 Generators. Final Crada Report. (open access)

Production of ra225 Precursor for ac225/bi213 Generators. Final Crada Report.

Russian subcontractors shipped two small deliveries of Ra225 to PNNL for evaluation. The activity was close to the requisite amount in the subcontract. The first labeled properly; the second did not. This showed that the Russians could supply Ra225 to the US; however they proved unable to meet future demands for larger amounts of activity. The US DOE attempts to get Ra225 from Russian should be terminated; the Russians, under Rosatom, are not interested in this business.
Date: October 2, 2009
Creator: Ehst, D. A.
Object Type: Report
System: The UNT Digital Library
Supply of purified Th228 for Ra224 generators. Final CRADA Report . (open access)

Supply of purified Th228 for Ra224 generators. Final CRADA Report .

CRADA was terminated when it was determined that the Russians could not perform the terms of the subcontract. It became apparent that the Russians would not be a reliable source of Th228, as a precursor in the decay chain which leads to Ra224. Their government policies will prohibit the export of Th228 in quantities needed for commercial cancer therapy.
Date: October 2, 2009
Creator: Ehst, D. A.
Object Type: Report
System: The UNT Digital Library
Technology development for Sr-89 production with 100kW medical isotope production system (MIPS-100). Final CRADA Report. (open access)

Technology development for Sr-89 production with 100kW medical isotope production system (MIPS-100). Final CRADA Report.

None
Date: October 2, 2009
Creator: Ehst, D. A.
Object Type: Report
System: The UNT Digital Library
Theory of Electron-Ion Collisions (open access)

Theory of Electron-Ion Collisions

Collisions of electrons with atoms and ions play a crucial role in the modeling and diagnostics of fusion plasmas. In the edge and divertor regions of magnetically confined plasmas, data for the collisions of electrons with neutral atoms and low charge-state ions are of particular importance, while in the inner region, data on highly ionized species are needed. Since experimental measurements for these collisional processes remain very limited, data for such processes depend primarily on the results of theoretical calculations. Over the period of the present grant (January 2006 – August 2009), we have made additional improvements in our parallel scattering programs, generated data of direct fusion interest and made these data available on The Controlled Fusion Atomic Data Center Web site at Oak Ridge National Laboratory. In addition, we have employed these data to do collsional-radiative modeling studies in support of a variety of experiments with magnetically confined fusion plasmas.
Date: October 2, 2009
Creator: Griffin, Donald C.
Object Type: Report
System: The UNT Digital Library