Recent Developments in Neutrino Science: A Whole Lot About Almost Nothing (open access)

Recent Developments in Neutrino Science: A Whole Lot About Almost Nothing

Results from Super-K, SNO, and KamLAND provide strong evidence that neutrinos undergo flavor-changing oscillations and therefore have non-zero mass. The {nu}-disappearance observations by KamLAND, assuming CPT conservation, point to matter enhanced (MSW) oscillations with large mixing angles as the solution to the solar neutrino problem--a result consistent with the MSW parameters recently defined by these experiments. This requires that the observed neutrino flavors (e, {mu}, and tau) are not mass eigenstates, but are linear combinations of the mass eigenstates of the neutrino. However, such oscillation experiments can only determine the differences in the masses of the neutrinos, not the absolute scale of neutrino mass. What can be inferred from these experiments is that at least one species of neutrino has a mass greater than 55 meV. In fact, the WMAP observations of large-scale structure point to a sum-neutrino mass of {approx} 0.7 eV (roughly 0.25 eV/species assuming democracy between the flavors). Furthermore, there is still the important issue of whether the neutrino and anti-neutrino are distinct particles (i.e. Dirac type) or not (Majorana type). The only way to answer both of these questions is through neutrinoless double beta decay (DBD) experiments. CUORE (Cryogenic Underground Observatory for Rare Events) is a …
Date: August 22, 2005
Creator: Norman, E B
System: The UNT Digital Library
Heat Transfer from Condensate Droplets Falling through an Immiscible Layer of Tributyl Phosphate (open access)

Heat Transfer from Condensate Droplets Falling through an Immiscible Layer of Tributyl Phosphate

As part of a safety analysis of reactions in two-layer mixtures of nitric acid and tributyl phosphate (TBP), an experiment was conducted to study how steam condensate mixes with the TBP layer when steam passes over a TBP-nitric acid mixture. The experiments showed that the condensate does not form a separate layer on top of the TBP but instead percolates as droplets through the TBP layer. The temperature at the top surface of the TBP layer undergoes a step change increase when the initial condensate droplets reach the surface. Temperatures at the surface and within the TBP and aqueous layers subsequently approach a steady state distribution governed by laminar convection and radiation heat transfer from the vapor space above the two-layer mixture. The rate of temperature increase and the steady state temperature gradient are determined by a characteristic propagation velocity and a streamwise dispersion coefficient for heat transfer. The propagation velocity is the geometric mean of the thermal convection velocities for the organic and aqueous phases, and the dispersion coefficient equals 0.494 times the product of the superficial condensate droplet velocity and the diameter of the test vessel. The value of the dispersion coefficient agrees with the Joshi (1980) correlation …
Date: August 22, 2005
Creator: Laurinat, James E.
System: The UNT Digital Library
Implementing Information Security and Its Technology: A LineManagement Perspective (open access)

Implementing Information Security and Its Technology: A LineManagement Perspective

Assuring the security and privacy of institutionalinformation assets is a complex task for the line manager responsible forinternational and multi-national transactions. In the face of an unsureand often conflicting international legal framework, the line managermust employ all available tools in an Integrated Security and PrivacyManagement framework that ranges from legal obligations, to policy, toprocedure, to cutting edge technology to counter the rapidly evolvingcyber threat to information assets and the physical systems thatinformation systems control.
Date: August 22, 2005
Creator: Barletta, William A.
System: The UNT Digital Library
Separating Hazardous Aerosols from Ambient Aerosols: Role of Fluorescence-Spectral Determination, Aerodynamic Deflector and Pulse Aerodynamic Localizer (PAL) (open access)

Separating Hazardous Aerosols from Ambient Aerosols: Role of Fluorescence-Spectral Determination, Aerodynamic Deflector and Pulse Aerodynamic Localizer (PAL)

An aerosol deflection technique based on the single-shot UV-laser-induced fluorescence spectrum from a flowing particle is presented as a possible front-end bio-aerosol/hazardous-aerosol sensor/identifier. Cued by the fluorescence spectra, individual flowing bio-aerosol particles (1-10 {micro}m in diameter) have been successfully deflected from a stream of ambient aerosols. The electronics needed to compare the fluorescence spectrum of a particular particle with that of a pre-determined fluorescence spectrum are presented in some detail. The deflected particles, with and without going through a funnel for pulse aerodynamic localization (PAL), were collected onto a substrate for further analyses. To demonstrate how hazardous materials can be deflected, TbCl{sub 3} {center_dot} 6H{sub 2}O (a simulant material for some chemical forms of Uranium Oxide) aerosol particles (2 {micro}m in diameter) mixed with Arizona road dust was separated and deflected with our system.
Date: August 22, 2005
Creator: Pan, Yong-Le; Cobler, Patrick J.; Rhodes, Scott A.; Halverson, Justin & Chang, Richard K.
System: The UNT Digital Library
Multimode-diode-pumped gas (alkali-vapor) laser (open access)

Multimode-diode-pumped gas (alkali-vapor) laser

We report the first demonstration of a multimode-diode-pumped gas laser--Rb vapor operating on the 795 nm resonance transition. Peak output of {approx}1 Watt was obtained using a volume-Bragg-grating stabilized pump diode array. The laser's output radiance exceeded the pump radiance by a factor greater than 2000. Power scaling (by pumping with larger diode arrays) is therefore possible.
Date: August 22, 2005
Creator: Page, R H; Beach, R J & Kanz, V K
System: The UNT Digital Library
Density distribution for a polymer adsorbed at an oil-water interface (open access)

Density distribution for a polymer adsorbed at an oil-water interface

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Date: August 22, 2005
Creator: Cai, Jun & Prausnitz, John M.
System: The UNT Digital Library
Coupled Climate Model Appraisal a Benchmark for Future Studies (open access)

Coupled Climate Model Appraisal a Benchmark for Future Studies

The Program for Climate Model Diagnosis and Intercomparison (PCMDI) has produced an extensive appraisal of simulations of present-day climate by eleven representative coupled ocean-atmosphere general circulation models (OAGCMs) which were developed during the period 1995-2002. Because projections of potential future global climate change are derived chiefly from OAGCMs, there is a continuing need to test the credibility of these predictions by evaluating model performance in simulating the historically observed climate. For example, such an evaluation is an integral part of the periodic assessments of climate change that are reported by the Intergovernmental Panel on Climate Change. The PCMDI appraisal thus provides a useful benchmark for future studies of this type. The appraisal mainly analyzed multi-decadal simulations of present-day climate by models that employed diverse representations of climate processes for atmosphere, ocean, sea ice, and land, as well as different techniques for coupling these components (see Table). The selected models were a subset of those entered in phase 2 of the Coupled Model Intercomparison Project (CMIP2, Covey et al. 2003). For these ''CMIP2+ models'', more atmospheric or oceanic variables were provided than the minimum requirements for participation in CMIP2. However, the appraisal only considered those climate variables that were supplied from …
Date: August 22, 2005
Creator: Phillips, T. J.; AchutaRao, K.; Bader, D.; Covey, C.; Doutriaux, C. M.; Fiorino, M. et al.
System: The UNT Digital Library
Status Of Cryogenic Layering For NIF Ignition Targets (open access)

Status Of Cryogenic Layering For NIF Ignition Targets

Recent advances in cryogenic layering include the development of a self-contained and self-filling cro hohlraum, application of phase contrast x-ray measurements for ice layer characterization, an ice layer achieved with beta-layering which meets the NIF specification for surface roughness at 1.5 K below the triple point. In addition, recent results on target integration in a hohlraum show effective layer control using heaters on the hohlraum.
Date: August 22, 2005
Creator: Moody, J. D.; Kozioziemski, B. J.; London, R. L.; Montgomery, D. S.; Sanchez, J. J.; Sater, J. D. et al.
System: The UNT Digital Library
STRIPES AND SUPERCONDUCTIVITY IN CUPRATE SUPERCONDUCTORS (open access)

STRIPES AND SUPERCONDUCTIVITY IN CUPRATE SUPERCONDUCTORS

One type of order that has been observed to compete with superconductivity in cuprates involves alternating charge and antiferromagnetic stripes. Recent neutron scattering studies indicate that the magnetic excitation spectrum of a stripe-ordered sample is very similar to that observed in superconducting samples. In fact, it now appears that there may be a universal magnetic spectrum for the cuprates. One likely implication of this universal spectrum is that stripes of a dynamic form are present in the superconducting samples. On cooling through the superconducting transition temperature, a gap opens in the magnetic spectrum, and the weight lost at low energy piles up above the gap; the transition temperature is correlated with the size of the spin gap. Depending on the magnitude of the spin gap with respect to the magnetic spectrum, the enhanced magnetic scattering at low temperature can be either commensurate or incommensurate. Connections between stripe correlations and superconductivity are discussed.
Date: August 22, 2005
Creator: TRANQUADA, J.M.
System: The UNT Digital Library
Re-Visiting SPEAR After 25 Years (Presentation material) (open access)

Re-Visiting SPEAR After 25 Years (Presentation material)

The SPEAR machine was completed in 1972. It consists of a single ring about 80 meters in diameter and started its very productive life as a positron-electron collider circulating beams up to 4 GeV. Synchrotron radiation research began almost immediately parasitically, then as half the program in the 1980s, and then became the whole program in 1991. The original network surveys used optical theodolites and invar tapes to place ring monuments in their ideal positions at constant offsets from the lines of ring quadrupoles. Optical tooling techniques were used to reference the monuments and survey offset targets on fixtures attached to the magnets. For more than 20 years neither the monuments nor magnets were restored to their ideal positions; the obvious discrepancies were simply ''feathered''. In 1992 SLC technology was used for the first time to re-measure the network and map the magnets. The discovery of many multiple-millimeter problems spurred planning for a 1995 global re-alignment. In 1995, all storage ring magnets and beamlines were mapped and moved. The band of displacements from ideal was reduced from about +/- 5mm to +/- 0.5mm. Upon start-up, beam stored without correctors.
Date: August 22, 2005
Creator: Pietryka, M.; Gaydosh, M. & King, T.
System: The UNT Digital Library
Optical Tooling with a Laptop Data Collector (Presentation material) (open access)

Optical Tooling with a Laptop Data Collector (Presentation material)

It has long been understood that the transposition of data from printouts to data collection sheets, and the subsequent manipulation of this data with measurement values, is an obvious error source in optical tooling projects. Ideas for computerized data collection have been under consideration for some time, yet they lacked the versatility needed for even the most typical optical tooling jobs. Surveyors experienced with optical tooling were used to designing the measurement strategy that worked best for each job. There was no canned formula that worked with every case. After extensive field testing a program was developed that worked in as many cases as possible. The program contains ideal files for components and monumentation, format sheets for set-up and measurement of components, and a summary sheet of work accomplished so far. This allows for the step by step movement through the measurement process.
Date: August 22, 2005
Creator: Perry, M.; Gaudreault, F. M.; Gaydosh, M. & Rogers, M.
System: The UNT Digital Library