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Integrative Analysis of Transgenic Alfalfa (Medicago sativa L.) Suggests New Metabolic Control Mechanisms for Monolignol Biosynthesis (open access)

Integrative Analysis of Transgenic Alfalfa (Medicago sativa L.) Suggests New Metabolic Control Mechanisms for Monolignol Biosynthesis

Article on an integrative analysis of transgenic alfalfa (Medicago sativa L.) suggesting new metabolic control mechanisms for monolignol biosynthesis.
Date: May 2011
Creator: Lee, Yun; Chen, Fang; Gallego-Giraldo, Lina; Dixon, R. A. & Voit, Eberhard O.
System: The UNT Digital Library
Transmission of Information Between Complex Systems: 1/ f resonance (open access)

Transmission of Information Between Complex Systems: 1/ f resonance

In this article, the authors study the transport of information between two complex systems with similar properties.
Date: May 31, 2011
Creator: Aquino, Gerardo; Bologna, Mauro; West, Bruce J. & Grigolini, Paolo
System: The UNT Digital Library
Raman Spectroscopy of UH3 from the Hydrogen Corrosion of Uranium (open access)

Raman Spectroscopy of UH3 from the Hydrogen Corrosion of Uranium

Hydrogen reacts with a uranium surface to form a fine, pyrophoric metal power (UH{sub 3}). Few spectroscopic studies have been conducted to study this reaction. Advances in Raman spectroscopy permit the application of the Raman method to formally difficult areas of chemistry such as the hydrogen corrosion of uranium: availability of multiple laser excitation wavelengths; fiber optics delivery and collection systems; upgraded instrumentation and detection techniques; and development of special enclosed in situ reactor cells. UH{sub 3} vibrations are expected to occur at low frequencies due to extended U-H-U structure.
Date: May 31, 2011
Creator: Smyrl, N. R.; Stowe, A. C. & Powell, G. L.
System: The UNT Digital Library
Density Functional Theory in Surface Chemistry and Catalysis (open access)

Density Functional Theory in Surface Chemistry and Catalysis

Recent advances in the understanding of reactivity trends for chemistry at transition metal surfaces have enabled in silico design of heterogeneous catalysts in a few cases. Current status of the field is discussed with an emphasis on the role of coupling between theory and experiment and future challenges.
Date: May 19, 2011
Creator: Norskov, Jens
System: The UNT Digital Library
Monte Carlo Simulation of a Coded Aperture Thermal Neutron Camera (open access)

Monte Carlo Simulation of a Coded Aperture Thermal Neutron Camera

N/A
Date: May 8, 2011
Creator: I., Dioszegi; Salwen, C. & and Forman, I.
System: The UNT Digital Library
Retrocausal Effects as a Consequence of Quantum Mechanics Refined to Accommodate the Principle of Sufficient Reason (open access)

Retrocausal Effects as a Consequence of Quantum Mechanics Refined to Accommodate the Principle of Sufficient Reason

The principle of sufficient reason asserts that anything that happens does so for a reason: no definite state of affairs can come into being unless there is a sufficient reason why that particular thing should happen. This principle is usually attributed to Leibniz, although the first recorded Western philosopher to use it was Anaximander of Miletus. The demand that nature be rational, in the sense that it be compatible with the principle of sufficient reason, conflicts with a basic feature of contemporary orthodox physical theory, namely the notion that nature's response to the probing action of an observer is determined by pure chance, and hence on the basis of absolutely no reason at all. This appeal to pure chance can be deemed to have no rational fundamental place in reason-based Western science. It is argued here, on the basis of the other basic principles of quantum physics, that in a world that conforms to the principle of sufficient reason, the usual quantum statistical rules will naturally emerge at the pragmatic level, in cases where the reason behind nature's choice of response is unknown, but that the usual statistics can become biased in an empirically manifest way when the reason for …
Date: May 10, 2011
Creator: Stapp, Henry P.
System: The UNT Digital Library
A study of extraterrestrial antineutrino sources with the KamLAND detector (open access)

A study of extraterrestrial antineutrino sources with the KamLAND detector

We present the results of a search for extraterrestrial electron antineutrinos ({bar {nu}}{sub e}'s) in the energy range 8.3 MeV < E{sub {bar {nu}}}{sub e} < 30.8 MeV using the KamLAND detector. In an exposure of 4.53 kton-year, we identify 25 candidate events. All of the candidate events can be attributed to background, most importantly neutral current atmospheric neutrino interactions, setting an upper limit on the probability of {sup 8}B solar {nu}{sub e}'s converting into {bar {nu}}{sub e}'s at 5.3 x 10{sup -5} (90% C.L.). The present data also allows us to set more stringent limits on the diffuse supernova neutrino flux and on the annihilation rates for light dark matter particles.
Date: May 18, 2011
Creator: Collaboration, The KamLAND; Gando, A.; Gando, Y.; Ichimura, K.; Ikeda, H.; Inoue, K. et al.
System: The UNT Digital Library
Analysis of nuclear proliferation resistance reprocessing and recycling technologies (open access)

Analysis of nuclear proliferation resistance reprocessing and recycling technologies

The PUREX process has been progressively and continuously improved during the past three decades, and these improvements account for successful commercialization of reprocessing in a few countries. The renewed interest in nuclear energy and the international growth of nuclear electricity generation do not equate – and should not be equated -with increasing proliferation risks. Indeed, the nuclear renaissance presents a unique opportunity to enhance the culture of non-proliferation. With the recent revival of interest in nuclear technology, technical methods for prevention of nuclear proliferation are being revisited. Robust strategies to develop new advanced separation technologies are emerging worldwide for sustainability and advancement of nuclear energy with enhanced proliferation resistance. On the other hand, at this moment, there are no proliferation resistance advanced technologies. . Until now proliferation resistance as it applies to reprocessing has been focused on not separating a pure stream of weapons-usable plutonium. France, as an example, has proposed a variant of the PUREX process, the COEX TM process, which does not result on a pure plutonium product stream. A further step is to implement a process based on group extraction of actinides and fission products associated with a homogeneous recycling strategy (UNEX process in the US, GANEX …
Date: May 1, 2011
Creator: Paviet-Hartmann, Patricia; Cerefice, Gary; Stacey, Marcela & Bakhtiar, Steven
System: The UNT Digital Library
Iterative Algorithms for Ptychographic Phase Retrieval (open access)

Iterative Algorithms for Ptychographic Phase Retrieval

Ptychography promises diffraction limited resolution without the need for high resolution lenses. To achieve high resolution one has to solve the phase problem for many partially overlapping frames. Here we review some of the existing methods for solving ptychographic phase retrieval problem from a numerical analysis point of view, and propose alternative methods based on numerical optimization.
Date: May 3, 2011
Creator: Yang, Chao; Qian, Jianliang; Schirotzek, Andre; Maia, Filipe & Marchesini, Stefano
System: The UNT Digital Library
Searches for new physics at the Tevatron (open access)

Searches for new physics at the Tevatron

The Tevatron collider has provided the CDF and D0 experiences with large datasets as input to a rich program of searches for physics beyond the standard model. The results presented here are a partial survey of recent searches conducted by the two collaborations using up to 6 fb{sup -1} of data. The standard model (SM) of particles, despite its remarkable description of experimental data at the elementary particle level, has some deficiencies to explain what is observed in the universe: lack of anti-matter, existence of dark matter, etc. Working at the energy frontier, as was the case at the Tevatron for so many years, gives experimentalists the hope to discover new non-SM particles which would indicate some direction to follow at explaining these SM deficiencies. Over the years, the CDF and D0 experiments have gained experience in the detector responses to all particle types. It allows to look at a large number of different final states searching for deviations from the SM expectations. As the knowledge of detector particle responses becomes more accurate, the complexity of final states can increase. For a given final state signature, the non-observation of deviations from the SM prediction allows to constrain several models at …
Date: May 1, 2011
Creator: Jaffre, Michel
System: The UNT Digital Library
Real-time Studies of Shocked Polycrystalline Materials with Single-Pulse X-ray Diffraction (open access)

Real-time Studies of Shocked Polycrystalline Materials with Single-Pulse X-ray Diffraction

Characteristic K-α x-rays used for single-pulse XRD are conventionally produced by a 37-stage high-voltage Marx pulse generator coupled to a vacuum needle-and-washer x-ray diode via coaxial transmission line. A large field-of-view x-ray image plate detection system typically enables observation of several Debye-Scherrer rings. Recently, we have developed a fiber-optic reducer, coupled to a CCD camera, to obtain low-noise, large field-of-view images. The direct beam spot is produced by bremsstrahlung radiation attenuated by a twomillimeter tungsten beam stop. Determination of the direct beam position is necessary to perform the ring integration.
Date: May 25, 2011
Creator: Morgan, Dane V.
System: The UNT Digital Library
How Common are the Magellanic Clouds (open access)

How Common are the Magellanic Clouds

We introduce a probabilistic approach to the problem of counting dwarf satellites around host galaxies in databases with limited redshift information. This technique is used to investigate the occurrence of satellites with luminosities similar to the Magellanic Clouds around hosts with properties similar to the Milky Way in the object catalog of the Sloan Digital Sky Survey. Our analysis uses data from SDSS Data Release 7, selecting candidate Milky-Way-like hosts from the spectroscopic catalog and candidate analogs of the Magellanic Clouds from the photometric catalog. Our principal result is the probability for a Milky-Way-like galaxy to host N{sub sat} close satellites with luminosities similar to the Magellanic Clouds. We find that 81 percent of galaxies like the Milky Way have no such satellites within a radius of 150 kpc, 11 percent have one, and only 3.5 percent of hosts have two. The probabilities are robust to changes in host and satellite selection criteria, background-estimation technique, and survey depth. These results demonstrate that the Milky Way has significantly more satellites than a typical galaxy of its luminosity; this fact is useful for understanding the larger cosmological context of our home galaxy.
Date: May 20, 2011
Creator: Liu, Lulu; Gerke, Brian F.; Wechsler, Risa H.; Behroozi, Peter S.; Busha, Michael T. & /KIPAC, Menlo Park /SLAC
System: The UNT Digital Library
Lithium Wall Conditioning And Surface Dust Detection On NSTX (open access)

Lithium Wall Conditioning And Surface Dust Detection On NSTX

Lithium evaporation onto NSTX plasma facing components (PFC) has resulted in improved energy confinement, and reductions in the number and amplitude of edge-localized modes (ELMs) up to the point of complete ELM suppression. The associated PFC surface chemistry has been investigated with a novel plasma material interface probe connected to an in-vacuo surface analysis station. Analysis has demonstrated that binding of D atoms to the polycrystalline graphite material of the PFCs is fundamentally changed by lithium - in particular deuterium atoms become weakly bonded near lithium atoms themselves bound to either oxygen or the carbon from the underlying material. Surface dust inside NSTX has been detected in real-time using a highly sensitive electrostatic dust detector. In a separate experiment, electrostatic removal of dust via three concentric spiral-shaped electrodes covered by a dielectric and driven by a high voltage 3-phase waveform was evaluated for potential application to fusion reactors
Date: May 23, 2011
Creator: Skinner, C. H.; Bell, M. G.; Friesen, F. Q. L.; Heim, B.; Jaworski, M. A.; Kugel, H. et al.
System: The UNT Digital Library
Creep-fatigue of High Temperature Materials for VHTR: Effect of Cyclic Loading and Environment (open access)

Creep-fatigue of High Temperature Materials for VHTR: Effect of Cyclic Loading and Environment

Alloy 617 is the one of the leading candidate materials for Intermediate Heat eXchangers (IHX) of a Very High Temperature Reactor (VHTR). System start-ups and shut-downs as well as power transients will produce low cycle fatigue (LCF) loadings of components. Furthermore, the anticipated IHX operating temperature, up to 950°C, is in the range of creep so that creep-fatigue interaction, which can significantly increase the fatigue crack growth, may be one of the primary IHX damage modes. To address the needs for Alloy 617 codification and licensing, a significant creep-fatigue testing program is underway at Idaho National Laboratory. Strain controlled LCF tests including hold times up to 1800s at maximum tensile strain were conducted at total strain range of 0.3% and 0.6% in air at 950°C. Creep-fatigue testing was also performed in a simulated VHTR impure helium coolant for selected experimental conditions. The creep-fatigue tests resulted in failure times up to 1000 hrs. Fatigue resistance was significantly decreased when a hold time was added at peak stress and when the total strain was increased. The fracture mode also changed from transgranular to intergranular with introduction of a tensile hold. Changes in the microstructure were methodically characterized. A combined effect of temperature, …
Date: May 1, 2011
Creator: Cabet, Celine; Carroll, L.; Wright, R. & Madland, R.
System: The UNT Digital Library
Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems (open access)

Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring …
Date: May 1, 2011
Creator: Soelberg, Nick & Enneking, Joe
System: The UNT Digital Library
Max Tech Appliance Design: Potential for Maximizing U.S. Energy Savings through Standards (open access)

Max Tech Appliance Design: Potential for Maximizing U.S. Energy Savings through Standards

This study surveyed the technical potential for efficiency improvements in 150 categories of appliances and equipment representing 33 quads of primary energy use across the US economy in 2010 and (1) documented efficient product designs, (2) identified the most promising cross-cutting strategies, and (3) ranked national energy savings potential by end use. Savings were estimated using a method modeled after US Department of Energy priority-setting reports - simplified versions of the full technical and economic analyses performed for rulemakings. This study demonstrates that large savings are possible by replacing products at the end-of-life with ultra-efficient models that use existing technology. Replacing the 50 top energy-saving end-uses (constituting 30 quads of primary energy consumption in 2010) with today's best-on-market equivalents would save {approx}200 quads of US primary energy over 30 years (25% of consumption anticipated there from). For the 29 products for maximum feasible savings potential could be estimated, the savings were twice as high. These results demonstrate that pushing ultra-efficient products to market could significantly escalate carbon emission reductions and is a viable strategy for sustaining large emissions reductions through standards. The results of this analysis were used by DOE for new coverage prioritization, to identify key opportunities for product …
Date: May 6, 2011
Creator: Garbesi, Karina; Desroches, Louis-Benoit; Bolduc, Christopher; Burch, Gabriel; Hosseinzadeh, Griffin & Saltiel, Seth
System: The UNT Digital Library
Ekpyrosis and inflationary dynamics in heavy ion collisions: the role of quantum fluctuations (open access)

Ekpyrosis and inflationary dynamics in heavy ion collisions: the role of quantum fluctuations

We summarize recent significant progress in the development of a first-principles formalism to describe the formation and evolution of matter in very high energy heavy ion collisions. The key role of quantum fluctuations both before and after a collision is emphasized. Systematic computations are now feasible to address early time isotropization, flow, parton energy loss and the Chiral Magnetic Effect.
Date: May 23, 2011
Creator: Dusling, K.; Venugopalan, R. & Gelis, F.
System: The UNT Digital Library
Secondary Pollutants from Ozone Reaction with Ventilation Filters and Degradation of Filter Media Additives (open access)

Secondary Pollutants from Ozone Reaction with Ventilation Filters and Degradation of Filter Media Additives

Prior research suggests that chemical processes taking place on the surface of particle filters employed in buildings may lead to the formation of harmful secondary byproducts. We investigated ozone reactions with fiberglass, polyester, cotton/polyester and polyolefin filter media, as well as hydrolysis of filter media additives. Studies were carried out on unused media, and on filters that were installed for 3 months in buildings at two different locations in the San Francisco Bay Area. Specimens from each filter media were exposed to {approx}150 ppbv ozone in a flow tube under a constant flow of dry or humidified air (50percent RH). Ozone breakthrough was recorded for each sample over periods of {approx}1000 min; the ozone uptake rate was calculated for an initial transient period and for steady-state conditions. While ozone uptake was observed in all cases, we did not observe significant differences in the uptake rate and capacity for the various types of filter media tested. Most experiments were performed at an airflow rate of 1.3 L/min (face velocity = 0.013 m/s), and a few tests were also run at higher rates (8 to 10 L/min). Formaldehyde and acetaldehyde, two oxidation byproducts, were quantified downstream of each sample. Those aldehydes (m/z …
Date: May 1, 2011
Creator: Destaillats, Hugo; Chen, Wenhao; Apte, Michael; Li, Nuan; Spears, Michael; Almosni, Jérémie et al.
System: The UNT Digital Library
A Low Carbon Development Guide for Local Government Actions in China (open access)

A Low Carbon Development Guide for Local Government Actions in China

Local level actions are crucial for achieving energy-saving and greenhouse gas emission reduction targets. Yet it is challenging to implement new policies and actions due to a lack of information, funding, and capacity. This is particularly the case in developing countries such as China. Even though national energy intensity and carbon intensity targets have been set, most local governments do not have the knowledge regarding actions to achieve the targets, the cost-effectiveness of policies, the possible impact of policies, or how to design and implement a climate action plan. This paper describes a guidebook that was developed to motivate and provide local governments in China with information to create an action plan to tackle climate change and increase energy efficiency. It provides a simple step-by-step description of how action plans can be established and essential elements to be included - from preparing a GHG emission inventory to implementation of the plan. The guidebook also provides a comprehensive list of successful policies and best practices found internationally and in China to encourage low carbon development in industry, buildings, transportation, electric power generation, agriculture and forestry. This paper also presents indicators that can be used to define low-carbon development, as well as …
Date: May 1, 2011
Creator: Zheng, Nina; Zhou, Nan; Price, Lynn & Ohshita, Stephanie
System: The UNT Digital Library
Rapidly Moving Divertor Plates In A Tokamak (open access)

Rapidly Moving Divertor Plates In A Tokamak

It may be possible to replace conventional actively cooled tokamak divertor plates with a set of rapidly moving, passively cooled divertor plates on rails. These plates would absorb the plasma heat flux with their thermal inertia for ~10-30 sec, and would then be removed from the vessel for processing. When outside the tokamak, these plates could be cooled, cleaned, recoated, inspected, and then returned to the vessel in an automated loop. This scheme could provide nearoptimal divertor surfaces at all times, and avoid the need to stop machine operation for repair of damaged or eroded plates. We describe various possible divertor plate designs and access geometries, and discuss an initial design for a movable and removable divertor module for NSTX-U.
Date: May 16, 2011
Creator: Zweben, S.
System: The UNT Digital Library
The Structural Disorder and Lattice Stability of (Ba,Sr)(Co,Fe)O3 Complex Perovskites (open access)

The Structural Disorder and Lattice Stability of (Ba,Sr)(Co,Fe)O3 Complex Perovskites

The structural disorder and lattice stability of complex perovskite (Ba,Sr)(Co,Fe)O3, a promising cathode material for solid oxide fuel cells and oxygen permeation membranes, is explored by means of first principles DFT calculations. It is predicted that Ba and Sr ions easily exchange their lattice positions (A-cation disorder) similarly to Co and Fe ions (B-cation disorder). The cation antisite defects (exchange of A- and B-type cations) have a relatively high formation energy. The BSCF is predicted to exist in an equilibrium mixture of several phases and can decompose exothermically into the Ba- and Co-rich hexagonal (Ba,Sr)CoO3 and Sr- and Fe-rich cubic (Ba,Sr)FeO3 perovskites.
Date: May 1, 2011
Creator: S.N.Rashkeev
System: The UNT Digital Library
On scale and magnitude of pressure build-up induced by large-scale geologic storage of CO2 (open access)

On scale and magnitude of pressure build-up induced by large-scale geologic storage of CO2

The scale and magnitude of pressure perturbation and brine migration induced by geologic carbon sequestration is discussed assuming a full-scale deployment scenario in which enough CO{sub 2} is captured and stored to make relevant contributions to global climate change mitigation. In this scenario, the volumetric rates and cumulative volumes of CO{sub 2} injection would be comparable to or higher than those related to existing deep-subsurface injection and extraction activities, such as oil production. Large-scale pressure build-up in response to the injection may limit the dynamic storage capacity of suitable formations, because over-pressurization may fracture the caprock, may drive CO{sub 2}/brine leakage through localized pathways, and may cause induced seismicity. On the other hand, laterally extensive sedimentary basins may be less affected by such limitations because (i) local pressure effects are moderated by pressure propagation and brine displacement into regions far away from the CO{sub 2} storage domain; and (ii) diffuse and/or localized brine migration into overlying and underlying formations allows for pressure bleed-off in the vertical direction. A quick analytical estimate of the extent of pressure build-up induced by industrial-scale CO{sub 2} storage projects is presented. Also discussed are pressure perturbation and attenuation effects simulated for two representative sedimentary basins …
Date: May 1, 2011
Creator: Zhou, Q. & Birkholzer, J. T.
System: The UNT Digital Library
Assessment of the Economic Potential of Microgrids for Reactive Power Supply (open access)

Assessment of the Economic Potential of Microgrids for Reactive Power Supply

As power generation from variable distributed energy resources (DER) grows, energy flows in the network are changing, increasing the requirements for ancillary services, including voltage support. With the appropriate power converter, DER can provide ancillary services such as frequency control and voltage support. This paper outlines the economic potential of DERs coordinated in a microgrid to provide reactive power and voltage support at its point of common coupling. The DER Customer Adoption Model assesses the costs of providing reactive power, given local utility rules. Depending on the installed DER, the cost minimizing solution for supplying reactive power locally is chosen. Costs include the variable cost of the additional losses and the investment cost of appropriately over-sizing converters or purchasing capacitors. A case study of a large health care building in San Francisco is used to evaluate different revenue possibilities of creating an incentive for microgrids to provide reactive power.
Date: May 1, 2011
Creator: Appen, Jan von; Marnay, Chris; Stadler, Michael; Momber, Ilan; Klapp, David & Scheven, Alexander von
System: The UNT Digital Library
Using an Energy Performance Based Design-Build Process to Procure a Large Scale Low-Energy Building: Preprint (open access)

Using an Energy Performance Based Design-Build Process to Procure a Large Scale Low-Energy Building: Preprint

This paper will review a procurement, acquisition, and contract process of a large-scale replicable net zero energy (ZEB) office building. The owners developed and implemented an energy performance based design-build process to procure a 220,000 ft2 office building with contractual requirements to meet demand side energy and LEED goals. We will outline the key procurement steps needed to ensure achievement of our energy efficiency and ZEB goals. The development of a clear and comprehensive Request for Proposals (RFP) that includes specific and measurable energy use intensity goals is critical to ensure energy goals are met in a cost effective manner. The RFP includes a contractual requirement to meet an absolute demand side energy use requirement of 25 kBtu/ft2, with specific calculation methods on what loads are included, how to normalize the energy goal based on increased space efficiency and data center allocation, specific plug loads and schedules, and calculation details on how to account for energy used from the campus hot and chilled water supply. Additional advantages of integrating energy requirements into this procurement process include leveraging the voluntary incentive program, which is a financial incentive based on how well the owner feels the design-build team is meeting the RFP …
Date: May 1, 2011
Creator: Pless, S.; Torcellini, P. & Shelton, D.
System: The UNT Digital Library