Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities (open access)

Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities

Chemical processes taking place in indoor environments can significantly alter the nature and concentrations of pollutants. Exposure to secondary contaminants generated in these reactions needs to be evaluated in association with many aspects of buildings to minimize their impact on occupant health and well-being. Focusing on indoor ozone chemistry, we describe alternatives for improving indoor air quality by controlling chemical changes related to building materials, ventilation systems, and occupant activities.
Date: May 1, 2006
Creator: Morrison, G. C.; Corsi, R. L.; Destaillats, H.; Nazaroff, W. W. & Wells, J. R.
System: The UNT Digital Library
High-Sensitivity Compton Imaging with Position-Sensitive Si and Ge Detectors (open access)

High-Sensitivity Compton Imaging with Position-Sensitive Si and Ge Detectors

None
Date: May 19, 2006
Creator: Vetter, K.; Burks, M.; Cork, C.; Cunningham, M.; Chivers, D.; Hull, E. et al.
System: The UNT Digital Library
Evaluating the energy performance of the first generation of LEED-certified commercial buildings (open access)

Evaluating the energy performance of the first generation of LEED-certified commercial buildings

Over three hundred buildings have been certified under the Leadership in Energy and Environmental Design (LEED) rating system for sustainable commercial buildings as of January 2006. This paper explores the modeled and actual energy performance of a sample of 21 of these buildings that certified under LEED between December 2001 and August 2005, including how extensively the design teams pursued LEED energy-efficiency credits, the modeled design and baseline energy performance, and the actual energy use during the first few years of operation. We collected utility billing data from 2003-2005 and compared the billed energy consumption with the modeled energy use. We also calculated Energy Star ratings for the buildings and compared them to peer groups where possible. The mean savings modeled for the sample was 27% compared to their modeled baseline values. For the group of 18 buildings for which we have both modeled and billed energy use, the mean value for actual consumption was 1% lower than modeled energy use, with a wide variation around the mean. The mean Energy Star score was 71 out of a total of 100 points, higher than the average score of 50 but slightly below the Energy Star award threshold of 75 points. …
Date: May 1, 2006
Creator: Diamond, Rick; Opitz, Mike; Hicks, Tom; Von Neida, Bill & Herrera, Shawn
System: The UNT Digital Library
Inflation model constraints from the Wilkinson Microwave Anisotropy Probe three-year data (open access)

Inflation model constraints from the Wilkinson Microwave Anisotropy Probe three-year data

We extract parameters relevant for distinguishing among single-field inflation models from the Wilkinson Microwave Anisotropy Probe (WMAP) three-year data set, and also from WMAP in combination with the Sloan Digital Sky Survey (SDSS) galaxy power spectrum. Our analysis leads to the following conclusions: (1) the Harrison-Zel'dovich model is consistent with both data sets at a 95% confidence level; (2) there is no strong evidence for running of the spectral index of scalar perturbations; (3) Potentials of the form V {infinity} {phi}{sup P} are consistent with the data for p = 2, and are marginally consistent with the WMAP data considered alone for p = 4, but ruled out by WMAP combined with SDSS. We perform a ''Monte Carlo reconstruction'' of the inflationary potential, and find that: (1) there is no evidence to support an observational lower bound on the amplitude of gravitational waves produced during inflation; (2) models such as simple hybrid potentials which evolve toward an inflationary late-time attractor in the space of flow parameters are strongly disfavored by the data, (3) models selected with even a weak slow-roll prior strongly cluster in the region favoring a ''red'' power spectrum and no running of the spectral index, consistent with …
Date: May 1, 2006
Creator: Kinney, William H.; /SUNY, Buffalo; Kolb, Edward W.; /Fermilab /Chicago U., Astron. Astrophys. Ctr.; Melchiorri, Alessandro; /Rome U. /INFN, Rome et al.
System: The UNT Digital Library
MODIFIED BOROHYDRIDES FOR REVERSIBLE HYDROGEN STORAGE (open access)

MODIFIED BOROHYDRIDES FOR REVERSIBLE HYDROGEN STORAGE

This paper reports the results in the effort to destabilize lithium borohydride for reversible hydrogen storage. A number of metals, metal hydrides, metal chlorides and complex hydrides were selected and evaluated as the destabilization agents for reducing dehydriding temperature and generating dehydriding-rehydriding reversibility. It is found that some additives are effective. The Raman spectroscopic analysis shows the change of B-H binding nature.
Date: May 10, 2006
Creator: Au, Ming
System: The UNT Digital Library
The Main Injector Beam Position Monitor Front-End Software (open access)

The Main Injector Beam Position Monitor Front-End Software

The front-end software developed for the Main Injector (MI) BPM upgrade is described. The software is responsible for controlling a VME crate, equipped with a Motorola PowerPC board running the VxWorks operating system, a custom made timing board and up to 10 commercial digitizer boards. The complete MI BPM system is composed of 7 independent units, each collecting data from 19 to 38 BPM pickups. The MI BPM system uses several components already employed on the successful upgrade of another Fermilab machine, the Tevatron. The front-end software framework developed for the Tevatron BPM upgrade is the base for building the MI front-end software. The framework is implemented in C++ as a generic component library (GBPM) that provides an event-driven data acquisition environment. Functionality of GBPM is extended to meet MI BPM requirements, such as the ability to handle and manage data from multiple cycles; perform readout of the digitizer boards without disrupting or missing subsequent cycles; transition between closed orbit and turn-by-turn modes within a cycle, using different filter and timing configurations; and allow the definition of new cycles during normal operation.
Date: May 1, 2006
Creator: Piccoli, Luciano; Foulkes, Stephen; Votava, Margaret & Briegel, Charles
System: The UNT Digital Library
CThC7 25 nJ Passively Mode-Locked Fiber Laser at 1080 nm (open access)

CThC7 25 nJ Passively Mode-Locked Fiber Laser at 1080 nm

None
Date: May 19, 2006
Creator: Messerly, M J; Dawson, J W; Barty, C J; An, J & Kim, D
System: The UNT Digital Library
Texture Control in Cerium Oxide Films (Poster) (open access)

Texture Control in Cerium Oxide Films (Poster)

The conclusions are: (1) Texture control is possible in cerium oxide by epitaxial growth or adjusting the substrate angle; (2) Biaxial (111) texture emerges with inclined angle depositions on glass; and (3) Biaxial (200) texture emerges by epitaxial growth on YSZ.
Date: May 1, 2006
Creator: van Hest, M. F. A. M.; Leenheer, A. J.; Perkins, J. D.; Teplin, C. W. & Ginley, D. S.
System: The UNT Digital Library
Plasma Surface Modification of Polymer Backsheets: Origins of Future Interfacial Barrier/Backsheet Failure (Poster) (open access)

Plasma Surface Modification of Polymer Backsheets: Origins of Future Interfacial Barrier/Backsheet Failure (Poster)

Flexible polymer substrates coated with inorganic oxide moisture barriers are a potential replacement for glass backsheets in thin-film PV (photovoltaic) modules. Silicon oxynitride (SiO{sub x}N{sub y}) deposited by plasma enhanced chemical vapor deposition (PECVD) on polyethylene terephthalate (PET) represents one potential new backsheet candidate. Barrier deposition runs at NREL have included a nitrogen-rich plasma pretreatment prior to barrier deposition with the intention of cleaning the PET surface and enhancing adhesion of the SiO{sub x}N{sub y} barrier film to PET; however, test coupons of PET/barrier/EVA/TPE failed after damp-heat exposure. (EVA is ethylene vinyl acetate and TPE is Tedlar{reg_sign}-PET-EVA). PET substrates exposed to plasma conditions similar to those used in pretreatment were examined by X-ray photoelectron spectroscopy (XPS) to reveal that new low molecular weight PET fragments were created at the PET surface. These fragments are responsible for barrier/PET interfacial failure and barrier transfer to the EVA encapsulant side following damp heat exposure.
Date: May 1, 2006
Creator: Pankow, J. W. & Glick, S. H.
System: The UNT Digital Library
Formation of ZnTe:Cu/Ti Contacts at High Temperature for CdS/CdTe Devices: Preprint (open access)

Formation of ZnTe:Cu/Ti Contacts at High Temperature for CdS/CdTe Devices: Preprint

We study the performance of CdS/CdTe thin-film devices contacted with ZnTe:Cu/Ti of various thickness at a higher-than-optimum temperature of {approx}360 C. At this temperature, optimum device performance requires the same thickness of ZnTe:Cu as for similar contacts formed at a lower temperature of 320 C. C-V analysis indicates that a ZnTe:Cu layer thickness of {approx}< 0.5 mu m does not yield the degree of CdTe net acceptor concentration necessary to reduce space charge width to its optimum value for n-p device operation. The thickest ZnTe:Cu layer investigated (1 mu m) yields the highest CdTe net acceptor concentration, lowest value of Jo, and highest Voc. However, performance is limited for this device by poor fill factor. We suggest poor fill factor is due to Cu-related acceptors compensating donors in CdS.
Date: May 1, 2006
Creator: Gessert, T. A.; Asher, S.; Johnston, S.; Duda, A.; Young, M. R. & Moriarty, T.
System: The UNT Digital Library
New Physics Searches at the Tevatron and the LHC (open access)

New Physics Searches at the Tevatron and the LHC

The Tevatron Run-II started data-taking in spring 2001 and several searches for new particles have been performed. The preliminary 2005 results are concisely reviewed for the experiments CDF and D0. Model-independent and model-dependent limits on Higgs boson and Supersymmetric particle production are set and interpretations are given. Several limits from the LEP era have been extended. The outlook for the Tevatron and the prospects for the ATLAS and CMS experiments at the LHC for selected searches are briefly addressed.
Date: May 1, 2006
Creator: Sopczak, Andre
System: The UNT Digital Library
GLAST Tracker (open access)

GLAST Tracker

The Large Area Telescope (LAT) on board the Gamma-ray Large-Area Space Telescope (GLAST) is a pair-conversion gamma-ray detector designed to explore the gamma-ray universe in the 20 MeV--300 GeV energy band. The Tracker subsystem of the LAT will perform tracking of electron and positrons to determine the origin of the gamma-ray. The design and performance of the GLAST LAT Tracker are described in this paper.
Date: May 1, 2006
Creator: Tajima, Hiroyasu
System: The UNT Digital Library
The System of Nanosecond 280-KeV He+ Pulsed Beam (open access)

The System of Nanosecond 280-KeV He+ Pulsed Beam

At Fast Neutron Research Facility, the 150 kV-pulses neutron generator is being upgraded to a 280-kV-pulsed-He beam for time-of-flight Rutherford backscattering spectrometry. It involves replacing the existing beam line elements by a multicusp ion source, a 400-kV accelerating tube, 45{sup o}-double focusing dipole magnet and quadrupole lens. The multicusp ion source is a compact filament-driven of 2.6 cm in diameter and 8 cm in length. The current extracted is 20.4 {micro}A with 13 kV of extraction voltage and 8.8 kV of Einzel lens voltage. The beam emittance has found to vary between 6-12 mm mrad. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. An optimized geometry for the 280 keV pulsed helium ion beam will be presented and discussed. The PARMELA code has been used to optimize the space charge effect, resulting in pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between chopper and buncher have been included in the optimization of …
Date: May 1, 2006
Creator: Junphong, P.; Ano, V.; Lekprasert, B.; Suwannakachorn, D.; Thongnopparat, N.; Vilaithong, T. et al.
System: The UNT Digital Library
Near infrared detectors for SNAP (open access)

Near infrared detectors for SNAP

Large format (1k x 1k and 2k x 2k) near infrared detectors manufactured by Rockwell Scientific Center and Raytheon Vision Systems are characterized as part of the near infrared R&D effort for SNAP (the Super-Nova/Acceleration Probe). These are hybridized HgCdTe focal plane arrays with a sharp high wavelength cut-off at 1.7 um. This cut-off provides a sufficiently deep reach in redshift while it allows at the same time low dark current operation of the passively cooled detectors at 140 K. Here the baseline SNAP near infrared system is briefly described and the science driven requirements for the near infrared detectors are summarized. A few results obtained during the testing of engineering grade near infrared devices procured for the SNAP project are highlighted. In particular some recent measurements that target correlated noise between adjacent detector pixels due to capacitive coupling and the response uniformity within individual detector pixels are discussed.
Date: May 23, 2006
Creator: Schubnell, M.; Barron, N.; Bebek, C.; Brown, M. G.; Borysow, M.; Cole, D. et al.
System: The UNT Digital Library
Polycrystalline Thin Film Photovoltaics: From the Laboratory to Solar Fields; Preprint (open access)

Polycrystalline Thin Film Photovoltaics: From the Laboratory to Solar Fields; Preprint

We review the status of commercial polycrystalline thin-film solar cells and photovoltaic (PV) modules, including current and projected commercialization activities.
Date: May 1, 2006
Creator: von Roedern, B.; Ullal, H. S. & Zweibel, K.
System: The UNT Digital Library
The Dark Energy Survey instrument design (open access)

The Dark Energy Survey instrument design

We describe a new project, the Dark Energy Survey (DES), aimed at measuring the dark energy equation of state parameter, w, to a statistical precision of {approx}5%, with four complementary techniques. The survey will use a new 3 sq. deg. mosaic camera (DECam) mounted at the prime focus of the Blanco 4m telescope at the Cerro-Tololo International Observatory (CTIO). DECam includes a large mosaic camera, a five element optical corrector, four filters (g,r,i,z), and the associated infrastructure for operation in the prime focus cage. The focal plane consists of 62 2K x 4K CCD modules (0.27''/pixel) arranged in a hexagon inscribed within the 2.2 deg. diameter field of view. We plan to use the 250 micron thick fully-depleted CCDs that have been developed at the Lawrence Berkeley National Laboratory (LBNL). At Fermilab, we will establish a packaging factory to produce four-side buttable modules for the LBNL devices, as well as to test and grade the CCDs. R&D is underway and delivery of DECam to CTIO is scheduled for 2009.
Date: May 1, 2006
Creator: Flaugher, B.
System: The UNT Digital Library
Comparative Studies of Proton Accelerators for High Power Applications. (open access)

Comparative Studies of Proton Accelerators for High Power Applications.

There are many applications requiring high power proton accelerators of various kinds. However, each type of proton accelerator can only provide beam with certain characteristics, hence the match of accelerators and their applications need careful evaluation. In this talk, the beam parameters and performance limitations of linac, cyclotron, synchrotron, and FFAG accelerators are studied and their relative merits for application in neutron, muon, neutrino, and ADS will be assessed in terms of beam energy, intensity, bunch length, repetition rate, and beam power requirements. A possible match between the applications and the accelerator of choice is presented in a matrix form. The accelerator physics and technology issues and challenges involved will also be discussed.
Date: May 29, 2006
Creator: Weng, W. T.
System: The UNT Digital Library
Dynamic response of single crystalline copper subjected to quasi-isentropic laser and gas-gun driven loading (open access)

Dynamic response of single crystalline copper subjected to quasi-isentropic laser and gas-gun driven loading

Single crystalline copper was subjected to quasi-isentropic compression via gas-gun and laser loading at pressures between 18 GPa and 59 GPa. The deformation substructure was analyzed via transmission electron microscopy (TEM). Twins and laths were evident at the highest pressures, and stacking faults and dislocation cells in the intermediate and lowest pressures, respectively. The Preston-Tonks-Wallace (PTW) constitutive description was used to model the slip-twinning process in both cases.
Date: May 22, 2006
Creator: Meyers, M; Jarmakani, H; McNaney, J; Schneider, M; Nguyen, J & Kad, B
System: The UNT Digital Library
Measurement of the Masses and Lifetimes of B Hadrons at the Tevatron (open access)

Measurement of the Masses and Lifetimes of B Hadrons at the Tevatron

The latest results for the B Hadron sector at the Tevatron Collider are summarized. The properties of B hadrons can be precisely measured at the Tevatron. In particularly they will focus on the masses and lifetimes. The new Tevatron results for the CP violation in B Hadrons are also discussed.
Date: May 1, 2006
Creator: Catastini, Pierluigi
System: The UNT Digital Library
Search for R-parity violating supersymmetry via the LL anti-E couplings lambda(121), lambda(122) or lambda(133) in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for R-parity violating supersymmetry via the LL anti-E couplings lambda(121), lambda(122) or lambda(133) in p anti-p collisions at s**(1/2) = 1.96-TeV

A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings {lambda}{sub 121}, {lambda}{sub 122}, or {lambda}{sub 133} is presented. The data, corresponding to an integrated luminosity of L {approx} 360 pb{sup -1}, were collected from April 2002 to August 2004 with the D0 detector at the Fermilab Tevatron Collider, at a center-of-mass energy of {radical}s = 1.96 TeV. This analysis considers final states with three charged leptons with the flavor combinations ee{ell}, {mu}{mu}{ell}, and ee{tau} ({ell} = e or {mu}). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the lightest neutralino and chargino are derived in two supersymmetric models.
Date: May 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Effect on Sb on the Properties of GaInP Top Cells: Preprint (open access)

Effect on Sb on the Properties of GaInP Top Cells: Preprint

It is well known that the efficiency of GaInP/GaAs tandem solar cells is limited by the band gap of the GaInP top cell, which, in turn, is determined by the degree of compositional ordering in GaInP base layer. Attempts to raise the band gap by the addition of Al to the top cell have met with limited success due to the strong affinity between Al and oxygen. Here we investigate a different approach. It has been shown that the presence of antimony on the surface of GaInP during its growth suppresses the ordering process and increases the band gap. In this paper, we study the effects of Sb on the properties of GaInP top cells. We show that, in addition to raising the band gap of GaInP, it also increases the incorporation of Zn and changes the relative incorporation of Ga and In. These effects depend strongly on the substrate orientation, growth temperature and rate, and the Sb/P ratio in the gas phase. We show that the band gap of the GaInP top cell (and the Voc) can be increased without reducing the minority carrier collection efficiency. The implications of these results are presented and discussed.
Date: May 1, 2006
Creator: Olson, J. M.; McMahon, W. E. & Kurtz, S.
System: The UNT Digital Library
A geoneutrino experiment at Homestake (open access)

A geoneutrino experiment at Homestake

A significant fraction of the 44 TW of heat dissipation from the Earth's interior is believed to originate from the decays of terrestrial uranium and thorium. The only estimates of this radiogenic heat, which is the driving force for mantle convection, come from Earth models based on meteorites, and have large systematic errors. The detection of electron antineutrinos produced by these uranium and thorium decays would allow a more direct measure of the total uranium and thorium content, and hence radiogenic heat production in the Earth. They discuss the prospect of building an electron antineutrino detector approximately 700 m{sup 3} in size in the Homestake mine at the 4850 feet level. This would allow us to make a measurement of the total uranium and thorium content with a statistical error less than the systematic error from the current knowledge of neutrino oscillation parameters. It would also allow us to test the hypothesis of a naturally occurring nuclear reactor at the center of the Earth.
Date: May 31, 2006
Creator: Tolich, Nikolai; Chan, Yuen-Dat; Currat, Charles A.; Decowski, M.Patrick; Fujikawa, Brian K.; Henning, Reyco et al.
System: The UNT Digital Library
Anodic Kinetics of NiCrMo Alloys During Localized Corrosion (open access)

Anodic Kinetics of NiCrMo Alloys During Localized Corrosion

This report describes how to acquire localized Corrosion kinetic maps for a series of NiCrMo alloys.
Date: May 3, 2006
Creator: Newman, R.C. & He, D.X.
System: The UNT Digital Library
Electron cooling in the recycler ring (open access)

Electron cooling in the recycler ring

None
Date: May 1, 2006
Creator: Shemyakin, Alexander
System: The UNT Digital Library