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The Sword of Data: Does Human-Centered Design Fulfill Its Rhetorical Responsibility? (open access)

The Sword of Data: Does Human-Centered Design Fulfill Its Rhetorical Responsibility?

This article discusses human-centered design, the guiding philosophy and process for more than twenty years in the field of design from both practice and pedagogy perspectives.
Date: July 2010
Creator: Friess, Erin
System: The UNT Digital Library
Beyond the Death of Linear Response: 1/f Optimal Information Transport (open access)

Beyond the Death of Linear Response: 1/f Optimal Information Transport

Article discussing research on linear response and 1/f optimal information transport.
Date: July 21, 2010
Creator: Aquino, Gerardo; Bologna, Mauro; Grigolini, Paolo & West, Bruce J.
System: The UNT Digital Library
Analytical solutions for a two-level system driven by a class of chirped pulses (open access)

Analytical solutions for a two-level system driven by a class of chirped pulses

Article on analytical solutions for a two-level system driven by a class of chirped pulses.
Date: July 6, 2010
Creator: Jha, Pankaj K. & Rostovtsev, Yuri V.
System: The UNT Digital Library
Flavin-Catalyzed Insertion of Oxygen into Rhenium-Methyl Bonds (open access)

Flavin-Catalyzed Insertion of Oxygen into Rhenium-Methyl Bonds

Article discussing flavin-catalyzed insertion of oxygen into rhenium-methyl bonds.
Date: July 24, 2010
Creator: Pouy, Mark J.; Milczek, Erika M.; Figg, Travis M.; Otten, Brooke M.; Prince, Bruce M.; Gunnoe, T. Brent et al.
System: The UNT Digital Library
Computational criteria for establishing reflex from plasticity to hardwiring (open access)

Computational criteria for establishing reflex from plasticity to hardwiring

Article accompanying a poster for the 2010 Computational Neuroscience Annual Meeting. This article discusses computational criteria for establishing reflex from plasticity to hardwiring.
Date: July 20, 2010
Creator: Tam, Nicoladie D.
System: The UNT Digital Library
Temporal associative memory (TAM) by spike-timing dependent plasticity (open access)

Temporal associative memory (TAM) by spike-timing dependent plasticity

Article accompanying a poster presentation for the 2010 Computational Neuroscience Meeting. This article discusses spike-timing dependent plasticity.
Date: July 2010
Creator: Tam, Nicoladie D.
System: The UNT Digital Library
Variables governing emotion and decision-making: human objectivity underlying its subjective perception (open access)

Variables governing emotion and decision-making: human objectivity underlying its subjective perception

This article accompanies a poster presentation on the variables governing emotion and decision-making.
Date: July 2010
Creator: Tam, Nicoladie D.
System: The UNT Digital Library
A General Treatment of Solubility 4. Description and Analysis of a PCA Model for Ostwald Solubility Coefficients (open access)

A General Treatment of Solubility 4. Description and Analysis of a PCA Model for Ostwald Solubility Coefficients

Article discussing a general treatment of solubility and a description and analysis of a principal component analysis (PCA) model for Ostwald solubility coefficients.
Date: July 1, 2010
Creator: Tulp, Indrek; Dobchev, Dimitar A.; Katritzky, Alan R.; Acree, William E. (William Eugene) & Maran, Uko, 1966-
System: The UNT Digital Library
People who Expect to Enter Psychotherapy are Prone to Believing that They Have Forgotten Memories of Childhood Trauma and Abuse (open access)

People who Expect to Enter Psychotherapy are Prone to Believing that They Have Forgotten Memories of Childhood Trauma and Abuse

Article discussing people who expect to enter psychotherapy being prone to believing that they have forgotten memories of childhood trauma and abuse.
Date: July 8, 2010
Creator: Rubin, David C. & Boals, Adriel
System: The UNT Digital Library
Genome-wide analysis of phenylpropanoid defence pathways (open access)

Genome-wide analysis of phenylpropanoid defence pathways

Article on genome-wide analysis of phenylpropanoid defence pathways.
Date: July 30, 2010
Creator: Naoumkina, Marina A.; Zhao, Qiao; Gallego-Giraldo, Lina; Dai, Xinbin; Zhao, Patrick Xuechun & Dixon, R. A.
System: The UNT Digital Library
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.
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.
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.
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
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.
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.
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.
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.
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
System: The UNT Digital Library
Cryogenic safety aspect of the low -$\beta$ magnest systems at the Large Hadron Collider (LHC) (open access)

Cryogenic safety aspect of the low -$\beta$ magnest systems at the Large Hadron Collider (LHC)

The low-{beta} magnet systems are located in the LHC insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process and will allow proton collisions at a luminosity of up to 10{sup 34}cm{sup -2}s{sup -1}. Large radiation dose deposited at the proximity of the beam collisions dictate stringent requirements for the design and operation of the systems. The hardware commissioning phase of the LHC was completed in the winter of 2010 and permitted to validate this system safe operation. This paper presents the analysis used to qualify and quantify the safe operation of the low-{beta} magnet systems in the Large Hadron Collider (LHC) for the first years of operation.
Date: July 1, 2010
Creator: Darve, C.
System: The UNT Digital Library
Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements (open access)

Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements

We report time-resolved Kerr effect measurements of magnetization dynamics in ferromagnetic SrRuO{sub 3}. We observe that the demagnetization time slows substantially at temperatures within 15K of the Curie temperature, which is {approx} 150K. We analyze the data with a phenomenological model that relates the demagnetization time to the spin flip time. In agreement with our observations the model yields a demagnetization time that is inversely proportional to T-T{sub c}. We also make a direct comparison of the spin flip rate and the Gilbert damping coefficient showing that their ratio very close to k{sub B}T{sub c}, indicating a common origin for these phenomena.
Date: July 30, 2010
Creator: Kantner, C. L. S.; Langner, M. C.; Siemons, W.; Blok, J. L.; Koster, G.; Rijnders, A.J. H. M. et al.
System: The UNT Digital Library
Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems (open access)

Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems

Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90percent of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems …
Date: July 8, 2010
Creator: Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon & Lee, Eleanor S.
System: The UNT Digital Library
Nonlinear Broadband Photoluminescence of Graphene Induced by Femtosecond Laser Irradiation (open access)

Nonlinear Broadband Photoluminescence of Graphene Induced by Femtosecond Laser Irradiation

Upon femtosecond laser irradiation, a bright, broadband photoluminescence is observed from graphene at frequencies well above the excitation frequency. Analyses show that it arises from radiative recombination of a broad distribution of nonequilibrium electrons and holes, generated by rapid scattering between photoexcited carriers within tens of femtoseconds after the optical excitation. Its highly unusual characteristics come from the unique electronic and structural properties of graphene.
Date: July 1, 2010
Creator: Liu, Wei-Tao; Wu, S.W.; Schuck, P.J.; Salmeron, Miquel; Shen, Y.R. & Wang, F.
System: The UNT Digital Library
Engineering the Electronic Band Structure for Multiband Solar Cells (open access)

Engineering the Electronic Band Structure for Multiband Solar Cells

Using the unique features of the electronic band structure of GaNxAs1-x alloys, we have designed, fabricated and tested a multiband photovoltaic device. The device demonstrates an optical activity of three energy bands that absorb, and convert into electrical current, the crucial part of the solar spectrum. The performance of the device and measurements of electroluminescence, quantum efficiency and photomodulated reflectivity are analyzed in terms of the Band Anticrossing model of the electronic structure of highly mismatched alloys. The results demonstrate the feasibility of using highly mismatched alloys to engineer the semiconductor energy band structure for specific device applications.
Date: July 12, 2010
Creator: Lopez, N.; Reichertz, L. A.; Yu, K. M.; Campman, K. & Walukiewicz, W.
System: The UNT Digital Library