Measured energy savings from the application of reflective roofsin 2 small non-residential buildings (open access)

Measured energy savings from the application of reflective roofsin 2 small non-residential buildings

Energy use and environmental parameters were monitored in two small (14.9 m{sup 2}) non-residential buildings during the summer of 2000. The buildings were initially monitored for about 1 1/2 months to establish a base condition. The roofs of the buildings were then painted with a white coating and the monitoring was continued. The original solar reflectivities of the roofs were about 26%; after the application of roof coatings the reflectivities increased to about 72%. The monitored electricity savings were about 0.5kWh per day (33 Wh/m2 per day). The estimated annual savings are about 125kWh per year (8.4 kWh/m2); at a cost of $0.1/kWh, savings are about $0.86/m2 per year. Obviously, it costs significantly more than this amount to coat the roofs with reflective coating, particularly because of the remote locations of these buildings. However, since the prefabricated roofs are already painted green at the factory, painting them a white (reflective) color would bring no additional cost. Hence, a reflective roof saves energy at no incremental cost.
Date: January 14, 2003
Creator: Akbari, Hashem
System: The UNT Digital Library
Global Cooling: Increasing World-Wide Urban Albedos to Offset CO2 (open access)

Global Cooling: Increasing World-Wide Urban Albedos to Offset CO2

Modification of urban albedos reduces summertime urban temperatures, resulting in a better urban air quality and building air-conditioning savings. Furthermore, increasing urban albedos has the added benefit of reflecting some of the incoming global solar radiation and countering to some extent the effects of global warming. In many urban areas, pavements and roofs constitute over 60% of urban surfaces (roof 20-25%, pavements about 40%). Using reflective materials, both roof and the pavement albedos can be increased by about 0.25 and 0.10, respectively, resulting in a net albedo increase for urban areas of about 0.1. Many studies have demonstrated building cooling-energy savings in excess of 20% upon raising roof reflectivity from an existing 10-20% to about 60% (a U.S. potential savings in excess of $1 billion (B) per year in net annual energy bills). On a global basis, our preliminary estimate is that increasing the world-wide albedos of urban roofs and paved surfaces will induce a negative radiative forcing on the earth equivalent to removing {approx} 22-40 Gt of CO{sub 2} from the atmosphere. Since, 55% of the emitted CO{sub 2} remains in the atmosphere, removal of 22-40 Gt of CO{sub 2} from the atmosphere is equivalent to reducing global CO{sub …
Date: January 14, 2008
Creator: Akbari, Hashem; Menon, Surabi & Rosenfeld, Arthur
System: The UNT Digital Library
Tracking down the origin of Arc plasma science. I. Early pulsed and oscillating discharges (open access)

Tracking down the origin of Arc plasma science. I. Early pulsed and oscillating discharges

None
Date: January 14, 2003
Creator: Anders, Andre
System: The UNT Digital Library
Tracking down the origin of Arc plasma science. II. Early continuous discharges (open access)

Tracking down the origin of Arc plasma science. II. Early continuous discharges

None
Date: January 14, 2003
Creator: Anders, Andre
System: The UNT Digital Library
Use of EBSD Data in Numerical Analyses (open access)

Use of EBSD Data in Numerical Analyses

Experimentation, theory and modeling have all played vital roles in defining what is known about microstructural evolution and the effects of microstructure on material properties. Recently, technology has become an enabling factor, allowing significant advances to be made on several fronts. Experimental evidence of crystallographic slip and the basic theory of crystal plasticity were established in the early 20th Century, and the theory and models evolved incrementally over the next 60 years. (Asaro provides a comprehensive review of the mechanisms and basic plasticity models.) During this time modeling was primarily concerned with the average response of polycrystalline aggregates. While some detailed finite element modeling (FEM) with crystal plasticity constitutive relations was done in the early 1980s, such simulations over taxed the capabilities of the available computer hardware. Advances in computer capability led to a flurry of activity in finite element modeling in the next 10 years, increasing understanding of microstructure evolution and pushing the limits of theories and material characterization. Automated Electron Back Scatter Diffraction (EBSD) has produced a similar revolution in material characterization. The data collected is extensive and many questions about the evolution of microstructure and its role in determining mechanic properties can now be addressed. It is …
Date: January 14, 2000
Creator: Becker, R & Wiland, H
System: The UNT Digital Library
The influence of cut off lows on sulfate burdens over the North Atlantic during April, 1987 (open access)

The influence of cut off lows on sulfate burdens over the North Atlantic during April, 1987

The authors have presented examples from a modeling study of the development of sulfur burdens over North America, the North Atlantic Ocean and Europe during April, 1987 using observation-derived meteorological data to represent the actual conditions for this period, focusing on the influence of cut-off lows on SO{sub 2} and sulfate column burdens over the North Atlantic Ocean. The analysis demonstrates that these systems can serve either as sources or sinks of sulfate, and that the major factor governing their resulting effect is the position during its formative stages relative to (a) sources of moisture, and (b) sulfur emissions, which regulates the availability of sulfur, cloud liquid water for sulfur oxidation, and the amount of precipitation for sulfate removal produced in the later stages of the life cycle.
Date: January 14, 2001
Creator: Benkovitz, C. M.; Miller, M. A.; Schwartz, S. E. & Kwon, O. U.
System: The UNT Digital Library
Noble gases and cosmogenic radionuclides in the Eltanin Pacific meteorite (open access)

Noble gases and cosmogenic radionuclides in the Eltanin Pacific meteorite

A 1.5 cm long, 1.2 g specimen of the Eltanin meteorite was found at 10.97 m depth in Polarstern piston core PS2704-1. The early studies indicated that the small fragments of the Eltanin meteorite was debris from a km-sized asteroid which impacted into the deep-ocean basin. In this study, the authors measured {sup 39}Ar-{sup 40}Ar age, noble gases, and cosmogenic radionuclides in splits of specimen as a part of consortium studies of Eltanin meteorite. They concluded that the specimen was about 3 m deep from the asteroid surface. The exposure age of the Eltanin asteroid was about 20 Myr.
Date: January 14, 2000
Creator: Bogard, D D; Garrison, D H; Caffee, M W; Kyte, F & Nishiizumi, K
System: The UNT Digital Library
Highly 15N-Enriched Chondritic Clasts in the Isheyevo Meteorite (open access)

Highly 15N-Enriched Chondritic Clasts in the Isheyevo Meteorite

The metal-rich carbonaceous chondrites (CB and CH) have the highest whole-rock {sup 15}N enrichment ({delta}{sup 15}N up to +1500{per_thousand}), similar to {delta}{sup 15}N values reported in micron-sized regions (hotspots) of Interplanetary Dust Particles (IDPs) of possibly cometary origin and fine-grained matrices of unmetamorphosed chondrites. These {sup 15}N-rich hotspots are commonly attributed to low-temperature ion-molecule reactions in the protosolar molecular cloud or in the outer part of the protoplanetary disk. The nature of the whole-rock {sup 15}N enrichment of the metal-rich chondrites is not understood. We report a discovery of a unique type of primitive chondritic clasts in the CH/CB-like meteorite Isheyevo, which provides important constraints on the origin of {sup 15}N anomaly in metal-rich chondrites and nitrogen-isotope fractionation in the Solar System. These clasts contain tiny chondrules and refractory inclusions (5-15 {micro}m in size), and abundant ferromagnesian chondrule fragments (1-50 {micro}m in size) embedded in the partly hydrated, fine-grained matrix material composed of olivines, pyroxenes, poorly-organized aromatic organics, phyllosilicates and other hydrous phases. The mineralogy and oxygen isotope compositions of chondrules and refractory inclusions in the clasts are similar to those in the Isheyevo host, suggesting formation at similar heliocentric distances. In contrast to the previously known extraterrestrial samples, the …
Date: January 14, 2009
Creator: Bonal, L; Huss, G R; Krot, A N; Nagashima, K; Ishii, H A; Bradley, J P et al.
System: The UNT Digital Library
Spatially Continuous Mixed Simplified P2-P1 Solutions for Multidimensional Geometries (open access)

Spatially Continuous Mixed Simplified P2-P1 Solutions for Multidimensional Geometries

The simplified P{sub N} (SP{sub N}) angular approximation to the neutron transport equation has received renewed interest in recent years [1-3]. The even-order simplified P{sub 2} angular approximation has been shown to yield improved accuracy over the P{sub 1} (diffusion) angular approximation for problems in which the P{sub 1} approximation is reasonably accurate [1]. In particular, integral quantities such as reaction rates and eigenvalues computed by the SP{sub 2} approximation are typically more accurate. The SP{sub 2} scalar flux spatial distributions are also often more accurate than the P{sub 1} distributions away from material interfaces and source discontinuities. However, the SP{sub 2} scalar flux distributions are spatially discontinuous at material interfaces and source discontinuities. These spatial discontinuities are unphysical, aesthetically displeasing, and can lead to large inaccuracies near interfaces. Brantley [4] has recently investigated combining the P{sub 1} and P{sub 2} angular approximations in planar geometry to eliminate the discontinuities in the P{sub 2} scalar flux distributions near material interfaces and source discontinuities. In essence, the P{sub 1} angular approximation is used at material interfaces and source discontinuities to obtain spatially continuous scalar flux distributions; the P{sub 2} angular approximation is utilized elsewhere to take advantage of its improved accuracy. …
Date: January 14, 2005
Creator: Brantley, P S & Tomasevic, D I
System: The UNT Digital Library
Exposure History of Separated Phases from the Kapoeta Meteorite (open access)

Exposure History of Separated Phases from the Kapoeta Meteorite

The cosmogenic radionuclides, {sup 10}Be (1.5 Ma), {sup 26}Al (0.705 Ma), {sup 36}Cl (0.301 Ma), and {sup 53}Mn (3.7 Ma) were measured in selected clasts and matrix samples from the howardite Kapoeta. This work is an extension of that based on {sup 10}Be and {sup 26}Al [1]. Recent work based on measurements of cosmogenic {sup 21}Ne suggest the possibility of a complex recent exposure history for Kapoeta. The measurement of these radionuclides, in conjunction with production rates based on Monte Carlo calculations, can constrain exposure conditions and durations. Taken together, the radionuclide data are entirely consistent with a single stage 4{pi} exposure lasting {approximately} 3 Ma.
Date: January 14, 2000
Creator: Caffee, M W; Nishiizumi, K & Mazarik, J
System: The UNT Digital Library
Mixed Electromagnetic and Circuit Simulations using a Higher-Order Hybrid Formulation (open access)

Mixed Electromagnetic and Circuit Simulations using a Higher-Order Hybrid Formulation

Standard surface impedance approximations are invalid at lower frequencies approaching DC since the cross sections of conductors are smaller than the skin depth. Hence, a volumetric formulation is typically used at these low frequencies for broadband simulation as necessitated in digital or ultra-wideband systems since the skin effect can be modeled explicitly. This modeling requires fine and frequency dependent volume meshing. However, an approach using higher-order elements and/or bases may alleviate these requirements. The intent of this paper is to present a tightly coupled circuit and hybrid boundary element (or integral equation)/finite element based electromagnetic simulation that has been coded in EIGER.
Date: January 14, 2004
Creator: Champagne, N J; Jandhyala, V & Rockway, J D
System: The UNT Digital Library
Assessing Caregiver for Team Interventions (ACT): A New Paradigm for Comprehensive Hospice Quality Care (open access)

Assessing Caregiver for Team Interventions (ACT): A New Paradigm for Comprehensive Hospice Quality Care

Article on a new paradigm for comprehensive hospice quality care and Assessing Caregivers for Team Interventions (ACT).
Date: January 14, 2009
Creator: Demiris, George; Oliver, Debra Parker & Wittenberg-Lyles, Elaine
System: The UNT Digital Library
Modeling Fluid Flow and Electrical Resistivity in Fractured Geothermal Reservoir Rocks (open access)

Modeling Fluid Flow and Electrical Resistivity in Fractured Geothermal Reservoir Rocks

Phase change of pore fluid (boiling/condensing) in rock cores under conditions representative of geothermal reservoirs results in alterations of the electrical resistivity of the samples. In fractured samples, phase change can result in resistivity changes that are more than an order of magnitude greater than those measured in intact samples. These results suggest that electrical resistivity monitoring may provide a useful tool for monitoring the movement of water and steam within fractured geothermal reservoirs. We measured the electrical resistivity of cores of welded tuff containing fractures of various geometries to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction. We then used the Nonisothermal Unsaturated Flow and Transport model (NUFT) (Nitao, 1998) to simulate the propagation of boiling fronts through the samples. The simulated saturation profiles combined with previously reported measurements of resistivity-saturation curves allow us to estimate the evolution of the sample resistivity as the boiling front propagates into the rock matrix. These simulations provide qualitative agreement with experimental measurements suggesting that our modeling approach may be used to estimate resistivity changes induced by boiling in more complex systems.
Date: January 14, 2003
Creator: Detwiler, R. L.; Roberts, J. J.; Ralph, W. & Bonner, B. P.
System: The UNT Digital Library
Development of one-equation transition/turbulence models (open access)

Development of one-equation transition/turbulence models

This paper reports on the development of a unified one-equation model for the prediction of transitional and turbulent flows. An eddy viscosity--transport equation for nonturbulent fluctuation growth based on that proposed by Warren and Hassan is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittency function based on the work of Dhawan and Narasimha. The model predicts both the onset and extent of transition. Low-speed test cases include transitional flow over a flat plate, a single element airfoil, and a multi-element airfoil in landing configuration. High-speed test cases include transitional Mach 3.5 flow over a 5{degree} cone and Mach 6 flow over a flared-cone configuration. Results are compared with experimental data, and the grid-dependence of selected predictions is analyzed.
Date: January 14, 2000
Creator: Edwards, J. R.; Roy, C. J.; Blottner, F. G. & Hassan, H. A.
System: The UNT Digital Library
Synthesis of superlow friction carbon films from hydrogen-rich acetylene plasmas. (open access)

Synthesis of superlow friction carbon films from hydrogen-rich acetylene plasmas.

None
Date: January 14, 2002
Creator: Erdemir, A; Eryilmaz, O. L.; Kazmanli, M. K. & Fenske, G.
System: The UNT Digital Library
DYNAMICAL RESPONSE OF QUASI ID MOTT INSULATORS. (open access)

DYNAMICAL RESPONSE OF QUASI ID MOTT INSULATORS.

At low energies certain one dimensional Mott insulators can be described in terms of an exactly solvable quantum field theory, the U(1) Thirring model. Using exact results derived from integrability we determine dynamical properties like the frequency dependent optical conductivity and the single-particle Green's function. We discuss the effects of a small temperature and the effects on interchain tunneling in a model of infinitely many weakly coupled chains.
Date: January 14, 2004
Creator: Essler, F. H. L. & Tsvelika, A. M.
System: The UNT Digital Library
A Linear RFQ Ion Trap for the Enriched Xenon Observatory (open access)

A Linear RFQ Ion Trap for the Enriched Xenon Observatory

The design, construction, and performance of a linear radio-frequency ion trap (RFQ) intended for use in the Enriched Xenon Observatory (EXO) are described. EXO aims to detect the neutrinoless double-beta decay of {sup 136}Xe to {sup 136}Ba. To suppress possible backgrounds EXO will complement the measurement of decay energy and, to some extent, topology of candidate events in a Xe filled detector with the identification of the daughter nucleus ({sup 136}Ba). The ion trap described here is capable of accepting, cooling, and confining individual Ba ions extracted from the site of the candidate double-beta decay event. A single trapped ion can then be identified, with a large signal-to-noise ratio, via laser spectroscopy.
Date: January 14, 2008
Creator: Flatt, B.; Green, M.; Wodin, J.; DeVoe, R.; Fierlinger, P.; Gratta, G. et al.
System: The UNT Digital Library
Comment on ``Experimental Free Energy Reconstruction From Single-Molecule Force Spectroscopy Using Jarzynski's Equality'' (open access)

Comment on ``Experimental Free Energy Reconstruction From Single-Molecule Force Spectroscopy Using Jarzynski's Equality''

Harris, Song and Kiang [1] (HSK) describe their results on reconstructing the free energy profiles for both the stretch of the titin polymer, and the unfolding of an individual I27 domain. The new finding reported in [1] is the measurement of the free energy barrier (or activation energy) to unfolding the I27 domain. Due to a misinterpretation of the mechanics involved, the free energy surface (and thus the energy barrier) to unfolding the I27 domain was not measured.
Date: January 14, 2008
Creator: Friddle, R. W.
System: The UNT Digital Library
Development of a Certified Low-Level Waste Stream from Analytical Laboratory Operations at Lawrence Livermore National Laboratory (open access)

Development of a Certified Low-Level Waste Stream from Analytical Laboratory Operations at Lawrence Livermore National Laboratory

Chemistry and Materials Science Environmental Services (CES) is LLNL's on-site environmental analytical laboratory, analyzing approximately 2500 samples annually generally for waste characterization purposes. Due to the lack of process knowledge for analyzed samples, the waste produced by CES has traditionally been characterized on a ''worst-case'' basis as RCRA-hazardous mixed waste. By instituting rigorous ''up-front'' waste characterization, including segregation of acutely/extremely hazardous materials, utilizing regulatory exemptions, and developing a novel radiological characterization strategy, CES was able to receive approval for a certified LLW waste stream, adequately characterized for disposal at the Nevada Test Site. In the 10 months of operating history, CES has diverted 33% of its waste (by mass) from mixed to LLW. This will result in significant cost savings and reduction in waste re-handling/personnel exposure.
Date: January 14, 2005
Creator: Gaylord, R. F.; Drake, J. A. & Gallagher, P. J.
System: The UNT Digital Library
Radiation Diffusion: An Overview of Physical and Numerical Concepts (open access)

Radiation Diffusion: An Overview of Physical and Numerical Concepts

An overview of the physical and mathematical foundations of radiation transport is given. Emphasis is placed on how the diffusion approximation and its transport corrections arise. An overview of the numerical handling of radiation diffusion coupled to matter is also given. Discussions center on partial temperature and grey methods with comments concerning fully implicit methods. In addition finite difference, finite element and Pert representations of the div-grad operator is also discussed
Date: January 14, 2005
Creator: Graziani, F R
System: The UNT Digital Library
Sensor Development and Readout Prototyping for the STAR Pixel Detector (open access)

Sensor Development and Readout Prototyping for the STAR Pixel Detector

The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D{sup 0} by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 {micro}s integration time, 400 M pixels and a coverage of -1 < {eta} < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.
Date: January 14, 2009
Creator: Greiner, L.; Anderssen, E.; Matis, H. S.; Ritter, H. G.; Stezelberger, T.; Szelezniak, M. et al.
System: The UNT Digital Library
Gauge unification in higher dimensions (open access)

Gauge unification in higher dimensions

A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z{sub 2}'s (Z{sub 2} and Z{sub 2}{prime}), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge symmetry breaking, doublet-triplet splitting, and a vanishing of proton decay from operators of dimension 5. Until 4d supersymmetry is broken, all proton decay from dimension 4 and dimension 5 operators is forced to vanish by an exact U(1){sub R} symmetry. Quarks and leptons and their Yukawa interactions are located at the Z{sub 2} orbifold fixed points, where SU(5) is unbroken. A new mechanism for introducing SU(5) breaking into the quark and lepton masses is introduced, which originates from the SU(5) violation in the zero-mode structure of bulk multiplets. Even though SU(5) is absent at the Z{sub 2}{prime} orbifold fixed point, the brane threshold corrections to gauge coupling unification are argued to be negligibly small, while the logarithmic corrections are small and in a direction which improves the agreement with the experimental measurements of the gauge couplings. Furthermore, the X gauge boson mass is lowered, so that p {yields} e{sup +}{pi}{sup 0} is expected with a rate within about one order of magnitude of the current …
Date: January 14, 2001
Creator: Hall, Lawrence & Nomura, Yasunori
System: The UNT Digital Library
A Time Projection Chamber for precision 239Pu(n,f) cross section measurement (open access)

A Time Projection Chamber for precision 239Pu(n,f) cross section measurement

High precision measurements of the {sup 239}Pu(n,f) cross section have been identified as important for the Global Nuclear Energy Partnership (GNEP) and other programs. Currently the uncertainty on this cross section is of the order 2-3% for neutron energies below 14 MeV and the goal is to reduce this to less than 1%. The Time Projection Chamber (TPC) has been identified as a possible tool to make this high precision measurement.
Date: January 14, 2008
Creator: Heffner, M
System: The UNT Digital Library
High Harmonic Fast Wave Heating Efficiency Enhancemen and Current Drive at Longer Wavelength on the National Spherical Torus Experiment (open access)

High Harmonic Fast Wave Heating Efficiency Enhancemen and Current Drive at Longer Wavelength on the National Spherical Torus Experiment

High harmonic fast wave heating and current drive (CD) are being developed on the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 41, 1435 (2001)] for supporting startup and sustainment of the ST plasma. Considerable enhancement of the core heating efficiency (η) from 44% to 65% has been obtained for CD phasing of the antenna (strap-to-strap φ = -90o, kφ = -8 m-1) by increasing the magnetic field from 4.5 kG to 5.5 kG. This increase in efficiency is strongly correlated to moving the location of the onset density for perpendicular fast wave propagation (nonset ∝ ΒΦ× k|| 2/w) away from the antenna face and wall, and hence reducing the propagating surface wave fields. RF waves propagating close to the wall at lower BΦ and k|| can enhance power losses from both the parametric decay instability (PDI) and wave dissipation in sheaths and structures around the machine. The improved efficiency found here is attributed to a reduction in the latter, as PDI losses are little changed at the higher magnetic field. Under these conditions of higher coupling efficiency, initial measurements of localized CD effects have been made and compared with advanced RF code simulations
Date: January 14, 2008
Creator: J. Hosea, R. E. Bell, B.P. LeBlanc, C.K. Phillips, G. Taylor, E. Valeo, J.R. Wilson, E.F. Jaeger, P.M. Ryan, J. Wilgen, H. Yuh, F. Levinton, S. Sabbagh, K. Tritz, J. Parker, P.T. Bonoli, R. Harvey, and the NSTX Team
System: The UNT Digital Library