Flight Tests of a Curtiss No. 838-1C2-18 Three-Blade Propeller Having Trailing-Edge Extensions (open access)

Flight Tests of a Curtiss No. 838-1C2-18 Three-Blade Propeller Having Trailing-Edge Extensions

"Flight tests to determine propeller performance have been made of a Curtiss No. 838-102-18 three-blade propeller having trailing-edge extensions on a Republic P-47D-28 airplane in climb and high speed. These tests are a part of a general propeller flight-test program at the Langley Laboratory of the National Advisory Committee for Aeronautics. Results of climb tests indicate that when power is changed from approximately 1475 horsepower at 2550 rpm (roughly normal power) to 2400 horsepower at 2700 rpm (approximately military power) there is a loss in propeller efficiency of 3 percent at an altitude of 7000 feet, and 4 percent at 21,000 feet" (p. 1).
Date: July 16, 1947
Creator: Gardner, John J.
Object Type: Report
System: The UNT Digital Library
Isomer ratio calculations using modeled discrete levels (open access)

Isomer ratio calculations using modeled discrete levels

Isomer ratio calculations were made for the reactions: /sup 175/Lu(n,..gamma..)/sup 176m,g/Lu, /sup 175/Lu(n,2n)/sup 174m,g/Lu, /sup 237/Np(n,2n)/sup 236m,g/Np, /sup 241/Am(n,..gamma..)/sup 242m,g/Am, and /sup 243/Am(n,..gamma..)/sup 244m,g/Am using modeled level structures in the deformed, odd-odd product nuclei. The hundreds of discrete levels and their gamma-ray branching ratios provided by the modeling are necessary to achieve agreement with experiment. Many rotational bands must be included in order to obtain a sufficiently representative selection of K quantum numbers. The levels of each band must be extended to appropriately high values of angular momentum.
Date: October 16, 1984
Creator: Gardner, M. A.; Gardner, D. G. & Hoff, R. W.
Object Type: Article
System: The UNT Digital Library
Absolute dipole gamma-ray strength functions for /sup 176/Lu. Supplement (open access)

Absolute dipole gamma-ray strength functions for /sup 176/Lu. Supplement

We have derived absolute dipole strength-function information for /sup 176/Lu from an average resonance capture study of /sup 175/Lu with 2-keV neutrons and from neutron capture cross-section measurements with neutrons from 30 keV to about 1 MeV. We found that we needed to increase our previous estimate of the relative M1/E1 strengths near 5 MeV by a factor of 3 and to revise downward the absolute magnitude of our E1 strength function. We accomplished the latter, while still maintaining continuity with the photonuclear data, by adjusting the one free parameter in our line shape. The present E1 and M1 strengths now seem correct both near the neutron separation energy and also around 1 MeV.
Date: October 16, 1984
Creator: Gardner, D. G.; Gardner, M. A. & Hoff, R. W.
Object Type: Article
System: The UNT Digital Library
Pair Production Constraints on Superluminal Neutrinos Revisited (open access)

Pair Production Constraints on Superluminal Neutrinos Revisited

We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.
Date: February 16, 2012
Creator: Brodsky, Stanley J. & Gardner, Susan
Object Type: Article
System: The UNT Digital Library
Setup and Performance of the Rhic Injector Accelerators for the 2005 Run With Copper Ions. (open access)

Setup and Performance of the Rhic Injector Accelerators for the 2005 Run With Copper Ions.

Copper ions for the 2005 run [1] of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of these accelerators with copper are reviewed in this paper.
Date: May 16, 2005
Creator: Ahrens, L.; Alessi, J. & Gardner, C. J.
Object Type: Article
System: The UNT Digital Library
The Impact of Intrinsic Heavy Quark Distributions in the Proton on New Physics Searches at the High Intensity Frontier (open access)

The Impact of Intrinsic Heavy Quark Distributions in the Proton on New Physics Searches at the High Intensity Frontier

The possibility of an intense proton facility, at 'Project X' or elsewhere, will provide many new opportunities for searches for physics beyond the Standard Model. A Project X can serve a yet broader role in the search for new physics, and in this note we highlight the manner in which thus-enabled studies of the flavor structure of the proton, particularly of its intrinsic heavy quark content, facilitate other direct and indirect searches for new physics. Intrinsic heavy quarks in both light and heavy hadrons play a key role in searches for physics BSM with hadrons - and their study at the Intensity Frontier may prove crucial to establishing its existence.
Date: February 16, 2012
Creator: Brodsky, Stanley & Gardner, Susan
Object Type: Article
System: The UNT Digital Library
High-energy measurements of neutron-induced fission cross-section ratios involving $sup 233$U, $sup 235$U, $sup 238$U, and $sup 239$Pu using the method of threshold cross sections (open access)
Nonoxide ceramic interactions with uranium or carbon. [Reaction of BN, TiN, HfC, CeS, or Ce2S3 with U, C, BeO, W, or Y2O3] (open access)

Nonoxide ceramic interactions with uranium or carbon. [Reaction of BN, TiN, HfC, CeS, or Ce2S3 with U, C, BeO, W, or Y2O3]

The interaction of possible nonoxide containment materials (including boron nitride, titanium nitride, hafnium carbide, and two cerium sulfides) with uranium or carbon has been examined by thermal analysis techniques. Additionally, nonoxide-ceramic interaction with beryllia, tungsten, or yttria was investigated. Hafnium carbide is the least reactive nonoxide ceramic tested.
Date: October 16, 1978
Creator: Holcombe, C.E.
Object Type: Article
System: The UNT Digital Library
Acceleration of Polarized Protons in the Ags With Two Helical Partial Snakes. (open access)

Acceleration of Polarized Protons in the Ags With Two Helical Partial Snakes.

The RHIC spin program requires 2 x 10{sup 11} proton/bunch with 70% polarization. As the injector to RHIC, AGS is the bottleneck for preserving polarization: there is no space for a full snake to overcome numerous depolarizing resonances. An ac dipole and a partial snake have been used to preserve beam polarization in the past few years. Two helical snakes have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate all depolarizing resonances encountered during acceleration. This paper presents the setup and preliminary results.
Date: May 16, 2005
Creator: Huang, H.; Ahrens, L.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C. et al.
Object Type: Article
System: The UNT Digital Library
Monte Carlo simulations of plutonium gamma-ray spectra (open access)

Monte Carlo simulations of plutonium gamma-ray spectra

Monte Carlo calculations were investigated as a means of simulating the gamma-ray spectra of Pu. These simulated spectra will be used to develop and evaluate gamma-ray analysis techniques for various nondestructive measurements. Simulated spectra of calculational standards can be used for code intercomparisons, to understand systematic biases and to estimate minimum detection levels of existing and proposed nondestructive analysis instruments. The capability to simulate gamma-ray spectra from HPGe detectors could significantly reduce the costs of preparing large numbers of real reference materials. MCNP was used for the Monte Carlo transport of the photons. Results from the MCNP calculations were folded in with a detector response function for a realistic spectrum. Plutonium spectrum peaks were produced with Lorentzian shapes, for the x-rays, and Gaussian distributions. The MGA code determined the Pu isotopes and specific power of this calculated spectrum and compared it to a similar analysis on a measured spectrum.
Date: July 16, 1993
Creator: Koenig, Z. M.; Carlson, J. B.; Wang, Tzu-Fang & Ruhter, W. D.
Object Type: Article
System: The UNT Digital Library
Status report to DOE Nuclear Data Committee (open access)

Status report to DOE Nuclear Data Committee

This status report includes brief reports on measurements and calculations of quantities for nuclear data applications and data for reactor safety. Separate abstracts were prepared for those items with a significant amount of data. (RWR)
Date: February 16, 1978
Creator: Anderson, J. D.; Browne, J. C. & Struble, G. L.
Object Type: Report
System: The UNT Digital Library
Performance Limitations in High-Energy Ion Colliders (open access)

Performance Limitations in High-Energy Ion Colliders

High-energy ion colliders (hadron colliders operating with ions other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams limits are set by space charge, charge exchange, and intrabeam scattering effects. The latter leads to luminosity lifetimes of only a few hours for intense heavy ions beams. Currently, the Relativistic Heavy Ion Collider (RHIC) at BNL is the only operating high-energy ion collider. Later this decade the Large Hadron Collider (LHC), under construction at CERN, will also run with heavy ions.
Date: May 16, 2005
Creator: Fischer, W.
Object Type: Article
System: The UNT Digital Library
Third geopressured-geothermal energy conference.Vol 2 (open access)

Third geopressured-geothermal energy conference.Vol 2

Twenty papers were included covering the Edna Delcambre Test Well, legal studies, environmental studies, economic studies, and resource utilization. Separate abstracts were prepared for each paper. (MHR)
Date: November 16, 1977
Creator: Meriwether, J.
Object Type: Article
System: The UNT Digital Library
Buggy-Top (open access)

Buggy-Top

Patent for certain new and useful improvements in buggy tops, including instructions and illustrations.
Date: January 16, 1900
Creator: Hughes, James F.
Object Type: Patent
System: The Portal to Texas History
A Method to Improve Activation of Implanted Dopants in SiC (open access)

A Method to Improve Activation of Implanted Dopants in SiC

Implantation of dopant ions in SiC has evolved according to the assumption that the best electrical results (i.e., carrier concentrations and mobility) is achieved by using the highest possible processing temperature. This includes implantation at > 600 C followed by furnace annealing at temperatures as high as 1,750 C. Despite such aggressive and extreme processing, implantation suffers because of poor dopant activation, typically ranging between < 2%--50% with p-type dopants represented in the lower portion of this range and n-types in the upper. Additionally, high-temperature processing can led to several problems including changes in the stoichiometry and topography of the surface, as well as degradation of the electrical properties of devices. A novel approach for increasing activation of implanted dopants in SiC and lowering the activation temperature will be discussed. This approach utilizes the manipulation of the ion-induced damage to enhance activation of implanted dopants. It will be shown that nearly amorphous layers containing a small amount of residual crystallinity can be recrystallized at temperatures below 900 C with little residual damage. It will be shown that recrystallization traps a high fraction of the implanted dopant residing within the amorphous phase (prior to annealing) onto substitutional sites within the SiC …
Date: January 16, 2001
Creator: Holland, O.W.
Object Type: Article
System: The UNT Digital Library
Stress analysis of the LOFT modular DTT flowmeter for LOCE transients (L1-5 and L2-4) (open access)

Stress analysis of the LOFT modular DTT flowmeter for LOCE transients (L1-5 and L2-4)

An analysis is presented of combined stresses in the LOFT Modular DTT for specified temperature gradients. All combined stress intensities are shown to stay within applicable allowable stress intensities. A fatigue analysis is also presented which indicates that the LOFT Modular DTT will withstand 70,000 blowdown cycles. The LOFT Modular DTT is shown to meet the Class 1 stress requirments. A stress analysis of the tab region of the newly designed MDTT tab-type shroud is included. This stress analysis shows that the Class 1 stress requirements are met by the tab-type MDTT shroud design and that this design imposes no fatigue life limitation on the MDTT.
Date: August 16, 1978
Creator: Mosby, W.R.
Object Type: Report
System: The UNT Digital Library
Non-Core Dry Hole Drilling at Cove Mesa, Arizona (open access)

Non-Core Dry Hole Drilling at Cove Mesa, Arizona

Abstract: A drilling program was conducted by the Atomic Energy Commission on Cove Mesa, Arizona to further develop uranium and vanadium ore reserves that are vital to the National Defense. The drilling was performed by the Minerals Engineering Company of Grand Junction, Colorado. Uranium and vanadium ore horizons are found in the Salt Wash member of the Morrison formation on Cove Mesa.
Date: June 16, 1952
Creator: Garcia, Raymond J.
Object Type: Report
System: The UNT Digital Library
Enhanced coal hydrogasification via oxidative pretreatment (open access)

Enhanced coal hydrogasification via oxidative pretreatment

The gasification of coal char by hydrogen is much slower than in steam or carbon dioxide; moreover, hydrogasification rate in pure hydrogen decreases sharply with conversion for most carbons. To overcome this kinetic behavior, the oxidation of the char prior to and during hydrogasification has been investigated as a means of enhancing hydro gasification rate. Kinetic rate studies under well-characterized conditions have been complemented by careful surface analyses to characterize oxygen on the char surface prior to and during hydrogasification.
Date: April 16, 1992
Creator: Miller, D.J.
Object Type: Report
System: The UNT Digital Library
Enhanced coal hydrogasification via oxidative pretreatment. Final technical report (open access)

Enhanced coal hydrogasification via oxidative pretreatment. Final technical report

The gasification of coal char by hydrogen is much slower than in steam or carbon dioxide; moreover, hydrogasification rate in pure hydrogen decreases sharply with conversion for most carbons. To overcome this kinetic behavior, the oxidation of the char prior to and during hydrogasification has been investigated as a means of enhancing hydro gasification rate. Kinetic rate studies under well-characterized conditions have been complemented by careful surface analyses to characterize oxygen on the char surface prior to and during hydrogasification.
Date: April 16, 1992
Creator: Miller, D. J.
Object Type: Report
System: The UNT Digital Library
SIMULATION OF NET INFILTRATION FOR MODERN AND POTENTIAL FUTURE CLIMATES (open access)

SIMULATION OF NET INFILTRATION FOR MODERN AND POTENTIAL FUTURE CLIMATES

This Analysis/Model Report (AMR) describes enhancements made to the infiltration model documented in Flint et al. (1996) and documents an analysis using the enhanced model to generate spatial and temporal distributions over a model domain encompassing the Yucca Mountain site, Nevada. Net infiltration is the component of infiltrated precipitation, snowmelt, or surface water run-on that has percolated below the zone of evapotranspiration as defined by the depth of the effective root zone, the average depth below the ground surface (at a given location) from which water is removed by evapotranspiration. The estimates of net infiltration are used for defining the upper boundary condition for the site-scale 3-dimensional Unsaturated-Zone Ground Water Flow and Transport (UZ flow and transport) Model (CRWMS M&O 2000a). The UZ flow and transport model is one of several process models abstracted by the Total System Performance Assessment model to evaluate expected performance of the potential repository at Yucca Mountain, Nevada, in terms of radionuclide transport (CRWMS M&O 1998). The net-infiltration model is important for assessing potential repository-system performance because output from this model provides the upper boundary condition for the UZ flow and transport model that is used to generate flow fields for evaluating potential radionuclide transport …
Date: June 16, 2000
Creator: Heveal, J. A.
Object Type: Report
System: The UNT Digital Library
Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry (open access)

Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the …
Date: March 16, 2006
Creator: McJimpsey, E. L.; Steele, P. T.; Coffee, K. R.; Fergenson, D. P.; Riot, V. J.; Woods, B. W. et al.
Object Type: Article
System: The UNT Digital Library
Measuring the efficacy of a root biobarrier with x-ray computed tomography (open access)

Measuring the efficacy of a root biobarrier with x-ray computed tomography

X-ray computed tomography is a useful tool for investigating soil physical properties nondestructively. There is a need to develop proper calibration relationships between soil properties and the x-ray absorption coefficient. The objective of the work was to evaluate soil factors affecting the x-ray absorption coefficient. Based on a theoretical analysis, experimental data from five soils and on results of several other investigators, it was concluded that for many applications, one calibration relationship is applicable to a wide range of soils. The montmorillinitic clay used in the study required special handling due to the extreme shrinkage of this soil upon drying. Knowledge of chemical composition enables approximations but not exact predictions of the x-ray absorption coefficient. The results suggested some reasonable alternative to exhaustive calibration for each anticipated soil condition. Quantification of root activity in terms of root growth and indirectly through water uptake is necessary for understanding plant growth dynamics. X-ray computed tomography (CT) enables qualitative as well as two quantitative outputs, one of which can lead to conclusions regarding root activity. A greenhouse study involving soil columns (Lakeland sand, bulk density 1.4 Mg/m{sup 3}) planted to soybean, Bahiagras, and control (no vegetation) was conducted in 1989. A treflan based …
Date: August 16, 1990
Creator: Tollner, E. W. & Murphy, C. E. Jr.
Object Type: Report
System: The UNT Digital Library
Dynamic Topography Change of the Eastern U. S. since 4 Ma: Implications for Sea Level and Stratigraphic Architecture of Passive Margins (open access)

Dynamic Topography Change of the Eastern U. S. since 4 Ma: Implications for Sea Level and Stratigraphic Architecture of Passive Margins

None
Date: August 16, 2011
Creator: Rowley, D B; Forte, A M; Moucha, R; Mitrovica, J X; Simmons, N A & Grand, S P
Object Type: Article
System: The UNT Digital Library
POLARIZED PROTON COLLISIONS AT RHIC. (open access)

POLARIZED PROTON COLLISIONS AT RHIC.

The Relativistic Heavy Ion Collider provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC. In 2002, polarized proton beams were first accelerated to 100 GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. Optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limited conditions are reported.
Date: May 16, 2005
Creator: Bai, M.; Ahrens, L.; Alekseev, I. G.; Alessi, J. & AL., ET
Object Type: Article
System: The UNT Digital Library