Resource Type

160 Matching Results

Results open in a new window/tab.

3HE RECOVERY FROM A TRITIUM-AGED LANA75 SAMPLE (open access)

3HE RECOVERY FROM A TRITIUM-AGED LANA75 SAMPLE

{sup 3}He recovery is a topic of recent interest. One potential recovery source is from metal hydride materials once used to store tritium, as the decay product, {sup 3}He, is primarily trapped in the metal lattice, usually in bubbles, with such materials. In 2001, a Tritium Exposure Program (TEP) sample known as LANA75-SP1 was retired and the material was removed from the test cell and stored. Subsequently scoping temperature programmed desorption (TPD) experiments were conducted on that material to see what it might take to drive out He and residual H isotopes (the heel). Two experiments consisted of heating the sample in the presence of an excess of tin (the so-called Sn fusion experiment), and one was a simple TPD with no additives. Prior data on the so-called '21-month bed' material in the 1980's had produced {approx}21 cc of gas per gram of a LANA30 material (LaNi4.7Al0.3), with approximately 67% of that being {sup 3}He and the rest being D{sub 2} (Fig.3). However, the material had to be heated in excess of 850 C to obtain that level. Heating to less produced approximately half that amount of gas. The data also showed that {sup 3}He was released at different temperatures …
Date: December 1, 2010
Creator: Shanahan, K.
System: The UNT Digital Library
Aliovalent titanium substitution in layered mixed Li Ni-Mn-Co oxides for lithium battery applications (open access)

Aliovalent titanium substitution in layered mixed Li Ni-Mn-Co oxides for lithium battery applications

Improved electrochemical characteristics are observed for Li[Ni1/3Co1/3-yMyMn1/3]O2 cathode materials when M=Ti and y<0.07, compared to the baseline material, with up to 15percent increased discharge capacity.
Date: December 1, 2010
Creator: Kam, Kinson & Doeff, Marca M.
System: The UNT Digital Library
Analysis of Off-Board Powered Thermal Preconditioning in Electric Drive Vehicles: Preprint (open access)

Analysis of Off-Board Powered Thermal Preconditioning in Electric Drive Vehicles: Preprint

Following a hot or cold thermal soak, vehicle climate control systems (air conditioning or heat) are required to quickly attain a cabin temperature comfortable to the vehicle occupants. In a plug-in hybrid electric or electric vehicle (PEV) equipped with electric climate control systems, the traction battery is the sole on-board power source. Depleting the battery for immediate climate control results in reduced charge-depleting (CD) range and additional battery wear. PEV cabin and battery thermal preconditioning using off-board power supplied by the grid or a building can mitigate the impacts of climate control. This analysis shows that climate control loads can reduce CD range up to 35%. However, cabin thermal preconditioning can increase CD range up to 19% when compared to no thermal preconditioning. In addition, this analysis shows that while battery capacity loss over time is driven by ambient temperature rather than climate control loads, concurrent battery thermal preconditioning can reduce capacity loss up to 7% by reducing pack temperature in a high ambient temperature scenario.
Date: December 1, 2010
Creator: Barnitt, R. A.; Brooker, A. D.; Ramroth, L.; Rugh , J. & Smith, K. A.
System: The UNT Digital Library
Beyond the Standard Model Higgs Boson Searches at the Tevatron (open access)

Beyond the Standard Model Higgs Boson Searches at the Tevatron

The search for the Higgs boson is one of the main goals in High Energy Physics and one of the highest priorities at Run II of the Tevatron. There are many alternative Higgs boson models beyond the SM, including Supersymmetry (SUSY) and Fermiophobic Higgs bosons, which can actively be probed at the Tevatron, and in the absence of an excess constrained. The latest limits for several SUSY searches are presented in Section 2 and for the Fermiophobic Higgs boson searches in Section 3. More information on all these searches, along with the latest results, can be found on the CDF and D0 public results webpages. Results are presented for beyond the Standard Model Higgs boson searches using up to 4.2 fb{sup -1} of data from Run II at the Tevatron. No significant excess is observed in any of the channels so 95% confidence level limits are presented.
Date: December 1, 2010
Creator: Scanlon, Tim
System: The UNT Digital Library
Challenges Surrounding the Injection and Arrival of Targets at LIFE Fusion Chamber Center (open access)

Challenges Surrounding the Injection and Arrival of Targets at LIFE Fusion Chamber Center

IFE target designers must consider several engineering requirements in addition to the physics requirements for successful target implosion. These considerations include low target cost, high manufacturing throughput, the ability of the target to survive the injection into the fusion chamber and arrive in a condition and physical position consistent with proper laser-target interaction and ease of post-implosion debris removal. This article briefly describes these considerations for the Laser Inertial Fusion-based Energy (LIFE) targets currently being designed.
Date: December 1, 2010
Creator: Miles, R.; Spaeth, M.; Manes, K.; Amendt, P.; Tabak, M.; Bond, T. et al.
System: The UNT Digital Library
CHARM 2010: Experiment summary and future charm facilities (open access)

CHARM 2010: Experiment summary and future charm facilities

The CHARM 2010 meeting had over 30 presentations of experimental results, plus additional future facilities talks just before this summary talk. Since there is not enough time to even summarize all that has been shown from experiments and to recognize all the memorable plots and results - tempting as it is to reproduce the many clean signals and data vs theory figures, the quantum correlations plots, and the D-mixing plots before and after the latest CLEO-c data is added. So, this review will give only my personal observations, exposing my prejudices and my areas of ignorance, no doubt. This overview will be at a fairly high level of abstraction - no re-showing individual plots or results. I ask the forgiveness of those who will have been slighted in this way - meaning all the presents.
Date: December 1, 2010
Creator: Appel, Jeffrey A.
System: The UNT Digital Library
Charmless and Penguin Decays at CDF (open access)

Charmless and Penguin Decays at CDF

Penguin transitions play a key role in the search of New Physics hints in the heavy flavor sector. During the last decade CDF has been exploring this opportunity with a rich study of two-body charmless decays of neutral B mesons into charged final-state particles. After briefly introducing the aspects of this physics peculiar to the hadron collision environment, I report on two interesting results: the first polarization measurement of the B{sub s}{sup 0} {yields} {phi}{phi} decay and the update of the B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} decays analysis.
Date: December 1, 2010
Creator: Dorigo, Mirco & Collaboration, for the CDF
System: The UNT Digital Library
Combination of Standard Model Higgs searches at CDF (open access)

Combination of Standard Model Higgs searches at CDF

We present the latest combination of searches for a standard model (SM) Higgs boson in p{bar p} collisions at {radical}s = 1.96 TeV recorded by the CDF II detector at the Fermilab Tevatron. Using data corresponding to 2.3-5.9 fb{sup -1} of integrated luminosity, we perform searches in a number of different production and decay modes and then combine them to improve sensitivity. No excess in data above that expected from backgrounds is observed; therefore, we set upper limits on the production cross section times branching fraction as a function of the SM Higgs boson mass (m{sub H}). The combined observed (expected) limit is 1.9 (1.8) times the SM prediction at m{sub H} =115 GeV/c{sup 2} and 1.0 (1.1) times the SM prediction at m{sub H} = 165 GeV/c{sup 2}.
Date: December 1, 2010
Creator: Potamianos, Karolos
System: The UNT Digital Library
Combined upper limit on standard model higgs boson production at D0 in $p \bar{p}$ collisions at $\sqrt{s} = 1.96-TeV (open access)

Combined upper limit on standard model higgs boson production at D0 in $p \bar{p}$ collisions at $\sqrt{s} = 1.96-TeV

The latest searches for the Standard Model Higgs boson at a centre-of-mass energy of {radical}s = 1.96 TeV with the D0 and the CDF detectors at the Fermilab Tevatron collider are presented. For the first time since the LEP experiments the sensitivity for a Standard Model Higgs boson has been reached at a Higgs boson mass of 170 GeV/c{sup 2}.
Date: December 1, 2010
Creator: Bernhard, Ralf
System: The UNT Digital Library
CP violation in the D0 -> pi+ pi- decay at CDF (open access)

CP violation in the D0 -> pi+ pi- decay at CDF

We report a measurement of the CP violating asymmetry in D{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays using approximately 215,000 decays reconstructed in about 5.94 fb{sup -1} of CDF data. We use the strong D*{sup +} {yields} D{sup 0}{pi}{sup +} decay ('D* tag') to identify the flavor of the charmed meson at production time and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. Higher statistic samples of Cabibbo-favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without D* tag are used to highly suppress systematic uncertainties due to detector effects. The result, A{sub CP}(D{sup 0} {yields} {pi}{sup +}{pi}{sup -}) = [0.22 {+-} 0.24 (stat.) {+-} 0.11 (syst.)]%, is the world's most precise measurement to date and it is fully consistent with no CP violation.
Date: December 1, 2010
Creator: Morello, Michael Joseph
System: The UNT Digital Library
Data Mining-Aided Crystal Engineering for the Design of Transparent Conducting Oxides: Preprint (open access)

Data Mining-Aided Crystal Engineering for the Design of Transparent Conducting Oxides: Preprint

The purpose of this paper is to accelerate the pace of material discovery processes by systematically visualizing the huge search space that conventionally needs to be explored. To this end, we demonstrate not only the use of empirical- or crystal chemistry-based physical intuition for decision-making, but also to utilize knowledge-based data mining methodologies in the context of finding p-type delafossite transparent conducting oxides (TCOs). We report on examples using high-dimensional visualizations such as radial visualization combined with machine learning algorithms such as k-nearest neighbor algorithm (k-NN) to better define and visualize the search space (i.e. structure maps) of functional materials design. The vital role of search space generated from these approaches is discussed in the context of crystal chemistry of delafossite crystal structure.
Date: December 1, 2010
Creator: Suh, C.; Kim, K.; Berry, J. J.; Lee, J. & Jones, W. B.
System: The UNT Digital Library
Detecting active comets with SDSS (open access)

Detecting active comets with SDSS

Using a sample of serendipitously discovered active comets in the Sloan Digital Sky Survey (SDSS), we develop well-controlled selection criteria for greatly increasing the efficiency of comet identification in the SDSS catalogs. After follow-up visual inspection of images to reject remaining false positives, the total sample of SDSS comets presented here contains 19 objects, roughly one comet per 10 million other SDSS objects. The good understanding of selection effects allows a study of the population statistics, and we estimate the apparent magnitude distribution to r {approx} 18, the ecliptic latitude distribution, and the comet distribution in SDSS color space. The most surprising results are the extremely narrow range of colors for comets in our sample (e.g. root-mean-square scatter of only {approx}0.06 mag for the g-r color), and the similarity of comet colors to those of jovian Trojans. We discuss the relevance of our results for upcoming deep multi-epoch optical surveys such as the Dark Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope (LSST), and estimate that LSST may produce a sample of about 10,000 comets over its 10-year lifetime.
Date: December 1, 2010
Creator: Solontoi, Michael; Ivezic, Zeljko; West, Andrew A.; Claire, Mark; Juric, Mario; Becker, Andrew et al.
System: The UNT Digital Library
Development of Performance Acceptance Test Guidelines for Large Commercial Parabolic Trough Solar Fields: Preprint (open access)

Development of Performance Acceptance Test Guidelines for Large Commercial Parabolic Trough Solar Fields: Preprint

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the EPC contractor or owners. In lieu of the present absence of engineering code developed for this purpose, NREL has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. The fundamental differences between acceptance of a solar power plant and a conventional fossil-fired plant are the transient nature of the energy source and the necessity to utilize an analytical performance model in the acceptance process. These factors bring into play the need to establish methods to measure steady state performance, potential impacts of transient processes, comparison to performance model results, and the possible requirement to test, or model, multi-day performance within the scope of the acceptance test procedure. The power block and BOP are not within the boundaries of this guideline. The current guideline is restricted to the solar thermal performance of parabolic trough systems and has been critiqued by a broad range of stakeholders in CSP development and technology.
Date: December 1, 2010
Creator: Kearney, D. & Mehos, M.
System: The UNT Digital Library
The ecloud measurement setup in the Main Injector (open access)

The ecloud measurement setup in the Main Injector

Ecloud has been observed in many high intensity accelerators which can limit the amount of current that can be stored in them. In particular, for ProjectX, the amount of beam current that will be stored in the MI (Main Injector) will be {approx}160 x 10{sup 12} protons while the present maximum intensity is {approx}45 x 10{sup 12} protons which is about 3.5x less beam. Although ecloud has been observed in the MI, it has not caused instabilities at the present running conditions. However, there is no guarantee that instabilities caused by ecloud will not be a problem at ProjectX intensities. Therefore, a program has been started to study the ecloud effects with both computer simulations and experiments. In this paper, we will be focusing our attention on how coatings can affect the production of secondary electrons. We have installed an ecloud measurement setup in a straight section of MI which consists of one coated and one uncoated beam pipe with the same physical dimensions and at the same location, together with four retarding field analyzers (RFAs) and three sets of beam position monitors (BPMs) which can be used for the microwave measurements. An ecloud measurement setup was installed in a …
Date: December 1, 2010
Creator: Tan, C.Y.; Backfish, M.; Zwaska, R. & /Fermilab
System: The UNT Digital Library
Electrospun a-Si using Liquid Silane/Polymer Inks (open access)

Electrospun a-Si using Liquid Silane/Polymer Inks

Amorphous silicon nanowires (a-SiNWs) were prepared by electrospinning cyclohexasilane (Si{sub 6}H{sub 12}) admixed with polymethylmethacrylate (PMMA) in toluene. Raman spectroscopy characterization of these wires (d {approx} 50-2000 nm) shows 350 C treatment yields a-SiNWs. Porous a-SiNWs are obtained using a volatile polymer.
Date: December 1, 2010
Creator: Schulz, D.L.; Hoey, J.M.; Smith, J.; Lovaasen, J.; Braun, C.; Dai, X. et al.
System: The UNT Digital Library
Energy-efficient specialization of functional units in a Coarse-Grained Reconfigurable Array (open access)

Energy-efficient specialization of functional units in a Coarse-Grained Reconfigurable Array

Functional units provide the backbone of any spatial accelerator by providing the computing resources. The desire for having rich and expensive functional units is in tension with producing a regular and energy-efficient computing fabric. This paper explores the design trade-off between complex, universal functional units and simpler, limited functional units. We show that a modest amount of specialization reduces the area-delay-energy product of an optimized architecture to 0.86x a baseline architecture. Furthermore, we provide a design guideline that allows an architect to customize the contents of the computing fabric just by examining the profile of benchmarks within the application domains. Functional units are the core of compute-intensive spatial accelerators. They perform the computation of interest with support from local storage and communication structures. Ideally, the functional units will provide rich functionality, supporting operations ranging from simple addition, to fused multiply-adds, to advanced transcendental functions and domain specific operations like add-compare-select. However, the total opportunity cost to support the more complex operations is a function of the cost of the hardware, the rate of occurrence of the operation in the application domain, and the inefficiency of emulating the operation with simpler operators. Examples of operations that are typically emulated in spatial …
Date: December 1, 2010
Creator: Van Essen, Brain; Panda, Robin; Wood, Aaron; Ebeling, Carl & Hauck, Scott
System: The UNT Digital Library
Error handling strategies in multiphase inverse modeling (open access)

Error handling strategies in multiphase inverse modeling

Parameter estimation by inverse modeling involves the repeated evaluation of a function of residuals. These residuals represent both errors in the model and errors in the data. In practical applications of inverse modeling of multiphase flow and transport, the error structure of the final residuals often significantly deviates from the statistical assumptions that underlie standard maximum likelihood estimation using the least-squares method. Large random or systematic errors are likely to lead to convergence problems, biased parameter estimates, misleading uncertainty measures, or poor predictive capabilities of the calibrated model. The multiphase inverse modeling code iTOUGH2 supports strategies that identify and mitigate the impact of systematic or non-normal error structures. We discuss these approaches and provide an overview of the error handling features implemented in iTOUGH2.
Date: December 1, 2010
Creator: Finsterle, S. & Zhang, Y.
System: The UNT Digital Library
Evaluating Future Standards and Codes with a Focus on High Penetration Photovoltaic (HPPV) System Deployment (Poster) (open access)

Evaluating Future Standards and Codes with a Focus on High Penetration Photovoltaic (HPPV) System Deployment (Poster)

Poster displaying solutions for evaluating future standards and codes for high penetration photovoltaic (HPPV) systems.
Date: December 1, 2010
Creator: Coddington, M.; Kroposki, B.; Basso, T. & Lynn, K.
System: The UNT Digital Library
First Experiences with LHC Grid Computing and Distributed Analysis (open access)

First Experiences with LHC Grid Computing and Distributed Analysis

In this presentation the experiences of the LHC experiments using grid computing were presented with a focus on experience with distributed analysis. After many years of development, preparation, exercises, and validation the LHC (Large Hadron Collider) experiments are in operations. The computing infrastructure has been heavily utilized in the first 6 months of data collection. The general experience of exploiting the grid infrastructure for organized processing and preparation is described, as well as the successes employing the infrastructure for distributed analysis. At the end the expected evolution and future plans are outlined.
Date: December 1, 2010
Creator: Fisk, Ian
System: The UNT Digital Library
IDR muon capture front end and variations (open access)

IDR muon capture front end and variations

The (International Design Report) IDR neutrino factory scenario for capture, bunching, phase-energy rotation and initial cooling of {mu}'s produced from a proton source target is explored. It requires a drift section from the target, a bunching section and a {phi}-{delta}E rotation section leading into the cooling channel. The rf frequency changes along the bunching and rotation transport in order to form the {mu}'s into a train of equal-energy bunches suitable for cooling and acceleration. Optimization and variations are discussed. An important concern is rf limitations within the focusing magnetic fields; mitigation procedures are described. The method can be extended to provide muons for a {mu}{sup +}-{mu}{sup -} Collider; variations toward optimizing that extension are discussed.
Date: December 1, 2010
Creator: Neuffer, David; Prior, Gersende; Rogers, Christopher; Snopok, Pavel & Yoshikawa, Cary
System: The UNT Digital Library
Irony and the 'yoga wars' (open access)

Irony and the 'yoga wars'

Article discussing the debated topic of whether yoga is a Hindu or Secular practice and the potential causes and impacts of how and why this subject is being debated.
Date: December 2010
Creator: Jain, Pankaj
System: The UNT Digital Library
Line-Focus Solar Power Plant Cost Reduction Plan (open access)

Line-Focus Solar Power Plant Cost Reduction Plan

Line-focus solar collectors, in particular parabolic trough collectors, are the most mature and proven technology available for producing central electricity from concentrated solar energy. Because this technology has over 25 years of successful operational experience, resulting in a low perceived risk, it is likely that it will continue to be a favorite of investors for some time. The concentrating solar power (CSP) industry is developing parabolic trough projects that will cost billions of dollars, and it is supporting these projects with hundreds of millions of dollars of research and development funding. While this technology offers many advantages over conventional electricity generation -- such as utilizing plentiful domestic renewable fuel and having very low emissions of greenhouse gases and air pollutants -- it provides electricity in the intermediate power market at about twice the cost of its conventional competitor, combined cycle natural gas. The purpose of this document is to define a set of activities from fiscal year 2011 to fiscal year 2016 that will make this technology economically competitive with conventional means.
Date: December 1, 2010
Creator: Kutscher, Charles; Mehos, Mark; Turchi, Craig; Glatzmaier, Greg & Moss, Timothy
System: The UNT Digital Library
Macro-System Model: A Federated Object Model for Cross-Cutting Analysis of Hydrogen Production, Delivery, Consumption and Associated Emissions; Preprint (open access)

Macro-System Model: A Federated Object Model for Cross-Cutting Analysis of Hydrogen Production, Delivery, Consumption and Associated Emissions; Preprint

It is commonly accepted that the introduction of hydrogen as an energy carrier for light-duty vehicles involves concomitant technological development of infrastructure elements, such as production, delivery, and consumption, all associated with certain emission levels. To analyze these at a system level, the suite of corresponding models developed by the United States Department of Energy and involving several national laboratories is combined in one macro-system model (MSM). The macro-system model is being developed as a cross-cutting analysis tool that combines a set of hydrogen technology analysis models. Within the MSM, a federated simulation framework is used for consistent data transfer between the component models. The framework is built to suit cross-model as well as cross-platform data exchange and involves features of 'over-the-net' computation.
Date: December 1, 2010
Creator: Ruth, M.; Diakov, V.; Goldsby, M. E. & Sa, T. J.
System: The UNT Digital Library
Model-Based Analysis of Electric Drive Options for Medium-Duty Parcel Delivery Vehicles: Preprint (open access)

Model-Based Analysis of Electric Drive Options for Medium-Duty Parcel Delivery Vehicles: Preprint

Medium-duty vehicles are used in a broad array of fleet applications, including parcel delivery. These vehicles are excellent candidates for electric drive applications due to their transient-intensive duty cycles, operation in densely populated areas, and relatively high fuel consumption and emissions. The National Renewable Energy Laboratory (NREL) conducted a robust assessment of parcel delivery routes and completed a model-based techno-economic analysis of hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle configurations. First, NREL characterized parcel delivery vehicle usage patterns, most notably daily distance driven and drive cycle intensity. Second, drive-cycle analysis results framed the selection of drive cycles used to test a parcel delivery HEV on a chassis dynamometer. Next, measured fuel consumption results were used to validate simulated fuel consumption values derived from a dynamic model of the parcel delivery vehicle. Finally, NREL swept a matrix of 120 component size, usage, and cost combinations to assess impacts on fuel consumption and vehicle cost. The results illustrated the dependency of component sizing on drive-cycle intensity and daily distance driven and may allow parcel delivery fleets to match the most appropriate electric drive vehicle to their fleet usage profile.
Date: December 1, 2010
Creator: Barnitt, R. A.; Brooker, A. D. & Ramroth, L.
System: The UNT Digital Library