Resource Type

Country

292 Matching Results

Results open in a new window/tab.

Bacterial Communities of the Coronal Sulcus and Distal Urethra of Adolescent Males (open access)

Bacterial Communities of the Coronal Sulcus and Distal Urethra of Adolescent Males

Article on bacterial communities of the coronal sulcus and distal urethra of adolescent males.
Date: May 11, 2012
Creator: Nelson, David E.; Dong, Qunfeng; Van Der Pol, Barbara; Toh, Evelyn; Fan, Baochang; Katz, Barry P. et al.
System: The UNT Digital Library
Generalization of Entropy Based Divergence Measures for Symbolic Sequence Analysis (open access)

Generalization of Entropy Based Divergence Measures for Symbolic Sequence Analysis

Article on the generalization of entropy based divergence measures for symbolic sequence analysis.
Date: September 17, 2013
Creator: Ré, Miguel A. & Azad, Rajeev K.
System: The UNT Digital Library
Factor structure of the Torrance Tests of Creative Thinking Figural Form A in Kiswahili speaking children: Multidimensionality and influences on creative behavior (open access)

Factor structure of the Torrance Tests of Creative Thinking Figural Form A in Kiswahili speaking children: Multidimensionality and influences on creative behavior

This article provides evidence for the valid use of the Torrance Tests of Creative Thinking (TTCT) in sub-Saharan Africa.
Date: November 19, 2016
Creator: Humble, Steve; Dixon, Pauline & Mpofu, Elias
System: The UNT Digital Library
Fighting Fire with Fire: Modeling the Datacenter-Scale Effects of Targeted Superlattice Thermal Management (open access)

Fighting Fire with Fire: Modeling the Datacenter-Scale Effects of Targeted Superlattice Thermal Management

Local thermal hot-spots in microprocessors lead to worst case provisioning of global cooling resources, especially in large-scale systems. However, efficiency of cooling solutions degrade non-linearly with supply temperature, resulting in high power consumption and cost in cooling - 50 {approx} 100% of IT power. Recent advances in active cooling techniques have shown on-chip thermoelectric coolers (TECs) to be very efficient at selectively eliminating small hot-spots, where applying current to a superlattice film deposited between silicon and the heat spreader results in a Peltier effect that spreads the heat and lowers the temperature of the hot-spot significantly to improve chip reliability. In this paper, we propose that hot-spot mitigation using thermoelectric coolers can be used as a power management mechanism to allow global coolers to be provisioned for a better worst case temperature leading to substantial savings in cooling power. In order to quantify the potential power savings from using TECs in data center servers, we present a detailed power model that integrates on-chip dynamic and leakage power sources, heat diffusion through the entire chip, TEC and global cooler efficiencies, and all their mutual interactions. Our multiscale analysis shows that, for a typical data center, TECs allow global coolers to operate …
Date: November 11, 2010
Creator: Biswas, S; Tiwari, M; Theogarajan, L; Sherwood, T P & Chong, F T
System: The UNT Digital Library
TARGET: A multi-channel digitizer chip for very-high-energy gamma-ray telescopes (open access)

TARGET: A multi-channel digitizer chip for very-high-energy gamma-ray telescopes

The next-generation very-high-energy (VHE) gamma-ray observatory, the Cherenkov Telescope Array, will feature dozens of imaging atmospheric Cherenkov telescopes (IACTs), each with thousands of pixels of photosensors. To be affordable and reliable, reading out such a mega-channel array requires event recording technology that is highly integrated and modular, with a low cost per channel. We present the design and performance of a chip targeted to this application: the TeV Array Readout with GSa/s sampling and Event Trigger (TARGET). This application-specific integrated circuit (ASIC) has 16 parallel input channels, a 4096-sample buffer for each channel, adjustable input termination, self-trigger functionality, and tight window-selected readout. We report the performance of TARGET in terms of sampling frequency, power consumption, dynamic range, current-mode gain, analog bandwidth, and cross talk. The large number of channels per chip allows a low cost per channel ($10 to $20 including front-end and back-end electronics but not including photosensors) to be achieved with a TARGET-based IACT readout system. In addition to basic performance parameters of the TARGET chip itself, we present a camera module prototype as well as a second-generation chip (TARGET 2), both of which have been produced.
Date: August 11, 2011
Creator: Bechtol, K.; Funk, S.; Okumura, A.; Ruckman, L.; Simons, A.; Tajima, H. et al.
System: The UNT Digital Library
A Terrestrial Search for Dark Contents of the Vacuum, Such as Dark Energy, Using Atom Interferometry (open access)

A Terrestrial Search for Dark Contents of the Vacuum, Such as Dark Energy, Using Atom Interferometry

We describe the theory and first experimental work on our concept for searching on earth for the presence of dark contents of the vacuum (DCV) using atom interferometry. Specifically, we have in mind any DCV that has not yet been detected on a laboratory scale, but which might manifest itself as dark energy on the cosmological scale. The experimental method uses two atom interferometers to cancel the effect of earth's gravity and diverse noise sources. It depends upon two assumptions: first, that the DCV possesses some space inhomogeneity in density, and second that it exerts a sufficiently strong nongravitational force on matter. The motion of the apparatus through the DCV should then lead to an irregular variation in the detected matter-wave phase shift. We discuss the nature of this signal and note the problem of distinguishing it from instrumental noise. We also discuss the relation of our experiment to what might be learned by studying the noise in gravitational wave detectors such as LIGO. The paper concludes with a projection that a future search of this nature might be carried out using an atom interferometer in an orbiting satellite. The laboratory apparatus is now being constructed.
Date: June 11, 2012
Creator: Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Muller, Holger; /UC, Berkeley; Perl, Martin L. & /KIPAC, Menlo Park /SLAC
System: The UNT Digital Library
An imaging proton spectrometer for short-pulse laser plasma experiments (open access)

An imaging proton spectrometer for short-pulse laser plasma experiments

Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better characterize these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only measure proton energy distribution with high resolution, but also provide its angular characteristics. The information obtained from this spectrometer compliments those from commonly used diagnostics including radiochromic film packs, CR39 nuclear track detectors, and non-imaging magnetic spectrometers. The basic characterizations and sample data from this instrument are presented.
Date: May 11, 2010
Creator: Chen, H.; Hazi, A.; van Maren, R.; Chen, S.; Fuchs, J.; Gauthier, M. et al.
System: The UNT Digital Library
Definitive Alkene Identification Needed for In-Vitro Studies with Ole (Olefin Synthesis) Proteins (open access)

Definitive Alkene Identification Needed for In-Vitro Studies with Ole (Olefin Synthesis) Proteins

None
Date: July 11, 2011
Creator: Beller, Harry; Goh, Ee-Been & Keasling, Jay
System: The UNT Digital Library
Direct probe of Mott-Hubbard to charge-transfer insulator transition and electronic structure evolution in transition-metal systems (open access)

Direct probe of Mott-Hubbard to charge-transfer insulator transition and electronic structure evolution in transition-metal systems

We report the most direct experimental verification of Mott-Hubbard and charge-transfer insulators through x-ray emission spectroscopy in transition-metal (TM) fluorides. The p-d hybridization features in the spectra allow a straightforward energy alignment of the anion-2p and metal-3d valence states, which visually shows the difference between the two types of insulators. Furthermore, in parallel with the theoretical Zaanen-Sawatzky-Allen diagram, a complete experimental systematics of the 3d Coulomb interaction and the 2p-3d charge-transfer energy is reported and could serve as a universal experimental trend for other TM systems including oxides.
Date: July 11, 2011
Creator: Olalde-Velasco, P.; Jimenez-Mier, J.; Denlinger, J. D.; Hussain, Z. & Yang, W. L.
System: The UNT Digital Library
Electron Correlation Effects in Uranium Dioxide from X-ray Emission Spectroscopy (open access)

Electron Correlation Effects in Uranium Dioxide from X-ray Emission Spectroscopy

None
Date: June 11, 2012
Creator: Yu, S W & Tobin, J G
System: The UNT Digital Library
Present Status And First Results of the Final Focus Beam Line at the KEK Accelerator Test Facility (open access)

Present Status And First Results of the Final Focus Beam Line at the KEK Accelerator Test Facility

ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.
Date: November 11, 2011
Creator: Bambade, P.; Alabau Pons, M.; Amann, J.; Angal-Kalinin, D.; Apsimon, R.; Araki, S. et al.
System: The UNT Digital Library
Coil Creep and Skew-Quadrupole Field Components in the Tevatron (open access)

Coil Creep and Skew-Quadrupole Field Components in the Tevatron

During the start-up of Run II of the Tevatron Collider program, several issues surfaced which were not present, or not seen as detrimental, during Run I. These included the repeated deterioration of the closed orbit requiring orbit smoothing every two weeks or so, the inability to correct the closed orbit to desired positions due to various correctors running at maximum limits, regions of systematically strong vertical dipole corrections, and the identification of very strong coupling between the two transverse degrees-of-freedom. It became apparent that many of the problems being experienced operationally were connected to a deterioration of the main dipole magnet alignment, and remedial actions were undertaken. However, the alignment alone was not enough to explain the corrector strengths required to handle transverse coupling. With one exception, strong coupling had generally not been an issue in the Tevatron during Run I. Based on experience with the Main Ring, the Tevatron was designed with a very strong skew quadrupole circuit to compensate any quadrupole alignment and skew quadrupole field errors that might present themselves. The circuit was composed of 48 correctors placed evenly throughout the arcs, 8 per sector, evenly placed in every other cell. Other smaller circuits were installed but …
Date: July 11, 2011
Creator: Annala, G.; Harding, D. J.; Syphers, M. J. & /Fermilab
System: The UNT Digital Library
A Heteroepitaxial Perovskite Metal-Base Transistor (open access)

A Heteroepitaxial Perovskite Metal-Base Transistor

'More than Moore' captures a concept for overcoming limitations in silicon electronics by incorporating new functionalities in the constituent materials. Perovskite oxides are candidates because of their vast array of physical properties in a common structure. They also enable new electronic devices based on strongly-correlated electrons. The field effect transistor and its derivatives have been the principal oxide devices investigated thus far, but another option is available in a different geometry: if the current is perpendicular to the interface, the strong internal electric fields generated at back-to-back heterojunctions can be used for oxide electronics, analogous to bipolar transistors. Here we demonstrate a perovskite heteroepitaxial metal-base transistor operating at room temperature, enabled by interface dipole engineering. Analysis of many devices quantifies the evolution from hot-electron to permeable-base behaviour. This device provides a platform for incorporating the exotic ground states of perovskite oxides, as well as novel electronic phases at their interfaces.
Date: August 11, 2011
Creator: Yajima, T.; Hikita, Y. & Hwang, H. Y.
System: The UNT Digital Library
Reco level Smin and subsystem Smin: improved global inclusive variables for measuring the new physics mass scale in MET events at hadron colliders (open access)

Reco level Smin and subsystem Smin: improved global inclusive variables for measuring the new physics mass scale in MET events at hadron colliders

The variable {radical}s{sub min} was originally proposed in [1] as a model-independent, global and fully inclusive measure of the new physics mass scale in missing energy events at hadron colliders. In the original incarnation of {radical}s{sub min}, however, the connection to the new physics mass scale was blurred by the effects of the underlying event, most notably initial state radiation and multiple parton interactions. In this paper we advertize two improved variants of the {radical}s{sub min} variable, which overcome this problem. First we show that by evaluating the {radical}s{sub min} variable at the RECO level, in terms of the reconstructed objects in the event, the effects from the underlying event are significantly diminished and the nice correlation between the peak in the {radical}s{sub min}{sup (reco)} distribution and the new physics mass scale is restored. Secondly, the underlying event problem can be avoided altogether when the {radical}s{sub min} concept is applied to a subsystem of the event which does not involve any QCD jets. We supply an analytic formula for the resulting subsystem {radical}s{sub min}{sup (sub)} variable and show that its peak exhibits the usual correlation with the mass scale of the particles produced in the subsystem. Finally, we contrast {radical}s{sub …
Date: August 11, 2011
Creator: Konar, Partha; Kong, Kyoungchul; Matchev, Konstantin T. & Park, Myeonghun
System: The UNT Digital Library
Surface and Electrochemical Behavior of HSLA in Supercritical CO2-H2O Environment (open access)

Surface and Electrochemical Behavior of HSLA in Supercritical CO2-H2O Environment

General corrosion was observed on high strength low alloy carbon steel after electrochemical impedance spectroscopy experiments (EIS) performed in H{sub 2}O saturated with CO{sub 2} at 50 C and 15.2 MPa. However, general and localized were observed on the same material surfaces after the EIS experiments performed in supercritical CO{sub 2} containing approximately 6100 ppmv H{sub 2}O at 50 C and 15.2 MPa. The general corrosion areas were uniformly covered by the FeCO{sub 3}-like phase identified by X-ray diffraction (XRD). In the area of localized corrosion, XRD also revealed FeCO{sub 3}-rich islands embedded in {alpha}-iron. The energy dispersive X-ray (EDX) analysis revealed high concentrations of iron, carbon, and oxygen in the area affected by general corrosion and in the islands formed in the area of localized corrosion. The real and imaginary impedances were lower in H{sub 2}O saturated with CO{sub 2} than those in the supercritical CO{sub 2} containing the aqueous phase indicating faster corrosion kinetics in the former.
Date: January 11, 2012
Creator: Ziomek-Moroz, M.; Holcomb, G. R.; Tylczak, J.; Beck, J.; Fedkin, M. & Lvov, S.
System: The UNT Digital Library
Searching for optimal mitigation geometries for laser resistant multilayer high reflector coatings (open access)

Searching for optimal mitigation geometries for laser resistant multilayer high reflector coatings

Growing laser damage sites on multilayer high reflector coatings can limit mirror performance. One of the strategies to improve laser damage resistance is to replace the growing damage sites with pre-designed benign mitigation structures. By mitigating the weakest site on the optic, the large aperture mirror will have a laser resistance comparable to the intrinsic value of the multilayer coating. To determine the optimal mitigation geometry, the finite difference time domain method (FDTD) was used to quantify the electric-field intensification within the multilayer, at the presence of different conical pits. We find that the field intensification induced by the mitigation pit is strongly dependent on the polarization and the angle of incidence (AOI) of the incoming wave. Therefore the optimal mitigation conical pit geometry is application specific. Furthermore, our simulation also illustrates an alternative means to achieve an optimal mitigation structure by matching the cone angle of the structure with the AOI of the incoming wave, except for the p-polarization wave at a range of incident angles between 30{sup o} and 45{sup o}.
Date: February 11, 2011
Creator: Qiu, S R; Wolfe, J E; Monterrosa, A M; Feit, M D; Pistor, T V & STolz, C J
System: The UNT Digital Library
Discovering New Light States at Neutrino Experiments (open access)

Discovering New Light States at Neutrino Experiments

Experiments designed to measure neutrino oscillations also provide major opportunities for discovering very weakly coupled states. In order to produce neutrinos, experiments such as LSND collide thousands of Coulombs of protons into fixed targets, while MINOS and MiniBooNE also focus and then dump beams of muons. The neutrino detectors beyond these beam dumps are therefore an excellent arena in which to look for long-lived pseudoscalars or for vector bosons that kinetically mix with the photon. We show that these experiments have significant sensitivity beyond previous beam dumps, and are able to partially close the gap between laboratory experiments and supernovae constraints on pseudoscalars. Future upgrades to the NuMI beamline and Project X will lead to even greater opportunities for discovery. We also discuss thin target experiments with muon beams, such as those available in COMPASS, and show that they constitute a powerful probe for leptophilic PNGBs.
Date: August 11, 2011
Creator: Essig, Rouven; Harnik, Roni; Kaplan, Jared & Toro, Natalia
System: The UNT Digital Library
Revisiting the Twist-3 Distribution Amplitudes of $K$ Meson within the QCD Background Field Approach (open access)

Revisiting the Twist-3 Distribution Amplitudes of $K$ Meson within the QCD Background Field Approach

None
Date: July 11, 2013
Creator: Zhong, Tao; U., /Chongqing; Wu, Xing-Gang; U., /SLAC /Chongqing; Han, Hua-Yong; Liao, Qi-Li et al.
System: The UNT Digital Library
U.S. Department of Energy (DOE)--Surface Biogeochemical Research (SBR) 6th Annual PI Meeting: Abstracts (open access)

U.S. Department of Energy (DOE)--Surface Biogeochemical Research (SBR) 6th Annual PI Meeting: Abstracts

On behalf of the Subsurface Biogeochemical Research (SBR) program managers in the Climate and Environmental Sciences Division (CESD), Office of Biological and Environmental Research (BER), welcome to the 2011 SBR Principal Investigators meeting. Thank you in advance for your attendance and your presentations at this year's meeting. As the events in Japan continue to unfold, we are all reminded that the research we perform on radionuclide behavior in the environment has implications beyond legacy waste cleanup and in fact has its place in the discussion on the expanded use of nuclear power. As in the past, there are three broad objectives to the Principal Investigators meeting: (1) to provide opportunities to share research results and promote interactions among the SBR scientists and other invited guests; (2) to evaluate the progress of each project within the program; and (3) to showcase the scientific expertise and research progress over the past year to senior managers within the DOE Office of Science, the technology offices within DOE, and other invited attendees from other Federal Agencies. This past year has seen a few significant changes within BER and within the SBR program. In November, our Associate Director for BER, Anna Palmisano, retired from Federal …
Date: April 11, 2011
Creator: Hazen Ed., T.C.
System: The UNT Digital Library
Online Physics Model Platform (open access)

Online Physics Model Platform

None
Date: October 11, 2013
Creator: Dohan, D.; Shen, G.; /Brookhaven; Chu, P.; Zhang, Y.; /Michigan State U., NSCL et al.
System: The UNT Digital Library
Order and disorder in the local and long-range structure of the spin-glass pyrochlore, Tb{sub 2}Mo{sub 2}O{sub 7} (open access)

Order and disorder in the local and long-range structure of the spin-glass pyrochlore, Tb{sub 2}Mo{sub 2}O{sub 7}

To understand the origin of the spin-glass state in molybdate pyrochlores, the structure of Tb{sub 2}Mo{sub 2}O{sub 7} is investigated using two techniques: the long-range lattice structure was measured using neutron powder diffraction (NPD), and local structure information was obtained from the extended x-ray absorption fine structure (EXAFS) technique. While the long-range structure appears generally well ordered, enhanced mean-squared site displacements on the O(1) site and the lack of temperature dependence of the strongly anisotropic displacement parameters for both the Mo and O(1) sites indicate some disorder exists. Likewise, the local structure measurements indicate some Mo-Mo and Tb-O(1) nearest-neighbor disorder exists, similar to that found in the related spin-glass pyrochlore, Y{sub 2}Mo{sub 2}O{sub 7}. Although the freezing temperature in Tb{sub 2}Mo{sub 2}O{sub 7}, 25 K, is slightly higher than in Y{sub 2}Mo{sub 2}O{sub 7}, 22 K, the degree of local pair distance disorder is actually less in Tb{sub 2}Mo{sub 2}O{sub 7}. This apparent contradiction is considered in light of the interactions involved in the freezing process.
Date: February 11, 2011
Creator: Jiang, Yu; Huq, Ashfia; Booth, Corwin H.; Ehlers, Georg; Greedan, John E. & Gardner, Jason S.
System: The UNT Digital Library
Summary of “Future of DIS” Working Group Session (open access)

Summary of “Future of DIS” Working Group Session

Despite the closure of the HERA accelerator in the past few years, much physics still remains to be understood, from the quark and gluon content of the nucleon/nucleus across all x to the still unknown spin structure of the proton. The 'Future of DIS' working group was dedicated to discussions on these and many other subjects. This paper represents a brief overview of the discussions. For further details, please refer to individual contributions.
Date: April 11, 2011
Creator: M., Lamont; Guzey, V. & Polini, A.
System: The UNT Digital Library
Lessons Learned from the 200 West Pump and Treatment Facility Construction Project at the US DOE Hanford Site - A Leadership for Energy and Environmental Design (LEED) Gold-Certified Facility (open access)

Lessons Learned from the 200 West Pump and Treatment Facility Construction Project at the US DOE Hanford Site - A Leadership for Energy and Environmental Design (LEED) Gold-Certified Facility

CH2M Hill Plateau Remediation Company (CHPRC) designed, constructed, commissioned, and began operation of the largest groundwater pump and treatment facility in the U.S. Department of Energy’s (DOE) nationwide complex. This one-of-a-kind groundwater pump and treatment facility, located at the Hanford Nuclear Reservation Site (Hanford Site) in Washington State, was built to an accelerated schedule with American Recovery and Reinvestment Act (ARRA) funds. There were many contractual, technical, configuration management, quality, safety, and Leadership in Energy and Environmental Design (LEED) challenges associated with the design, procurement, construction, and commissioning of this $95 million, 52,000 ft groundwater pump and treatment facility to meet DOE’s mission objective of treating contaminated groundwater at the Hanford Site with a new facility by June 28, 2012. The project team’s successful integration of the project’s core values and green energy technology throughout design, procurement, construction, and start-up of this complex, first-of-its-kind Bio Process facility resulted in successful achievement of DOE’s mission objective, as well as attainment of LEED GOLD certification, which makes this Bio Process facility the first non-administrative building in the DOE Office of Environmental Management complex to earn such an award.
Date: January 11, 2013
Creator: Dorr, Kent A.; Ostrom, Michael J. & Freeman-Pollard, Jhivaun R.
System: The UNT Digital Library
Development of MMC Gamma Detectors for Nuclear Analysis (open access)

Development of MMC Gamma Detectors for Nuclear Analysis

None
Date: July 11, 2013
Creator: Bates, C. R.; Pies, C.; Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C. et al.
System: The UNT Digital Library