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Multi-color light curves of type Ia supernovae on thecolor-magnitude diagram: A novel step toward more precise distance andextinction estimates (open access)

Multi-color light curves of type Ia supernovae on thecolor-magnitude diagram: A novel step toward more precise distance andextinction estimates

We show empirically that fits to the color-magnituderelation of Type Ia supernovae after optical maximum can provide accuraterelative extragalactic distances. We report the discovery of an empiricalcolor relation for Type Ia light curves: During much of the first monthpast maximum, the magnitudes of Type Ia supernovae defined at a givenvalue of color index have a very small magnitude dispersion; moreover,during this period the relation between B magnitude and B-V color (or B-Ror B-I color) is strikingly linear, to the accuracy of existingwell-measured data. These linear relations can provide robust distanceestimates, in particular, by using the magnitudes when the supernovareaches a given color. After correction for light curve stretch factor ordecline rate, the dispersion of the magnitudes taken at the intercept ofthe linear color-magnitude relation are found to be around 0^m .08 forthe sub-sample of supernovae with (B_max - V_max) ?= 0^m 0.5, andaround 0^m.11 for the sub-sample with (B_max - V_max) ?= 0^m .2.This small dispersion is consistent with being mostly due toobservational errors. The method presented here and the conventionallight curve fitting methods can be combined to further improvestatistical dispersions of distance estimates. It can be combined withthe magnitude at maximum to deduce dust extinction. Theslopes of thecolor-magnitude relation …
Date: January 31, 2003
Creator: Wang, Lifan; Goldhaber, Gerson; Aldering, Greg & Perlmutter, Saul
System: The UNT Digital Library
ENHANCING EFFECTIVENESS OF EMSP PROJECTS THROUGH STRONG CONNECTIONS TO SITE PROBLEMS (open access)

ENHANCING EFFECTIVENESS OF EMSP PROJECTS THROUGH STRONG CONNECTIONS TO SITE PROBLEMS

The Environmental Management Science Program (EMSP) funds basic science research that will lead to reduced remediation cost, schedule, technical uncertainties, and risk for DOE’s environmental clean up. The Tanks Focus Area (TFA) has partnered with EMSP to accomplish those same objectives for DOE’s largest and most expensive remediation effort – to retrieve and immobilize the highly radioactive wastes that are our nation's chief nuclear defense program legacy. TFA has been tasked to facilitate success of the EMSP investment. The key for EMSP projects to contribute to this remediation effort is communication. First, the scientist needs to understand much more about how his scientific results would be used than he could ever learn from the original EMSP solicitation or by reading the referenced DOE needs statements. Second, the scientist’s results must be communicated to the site problem holders in a usable form and in a timely manner such that important information gaps can still be filled by the EMSP project. Research results can be used in a variety of ways besides deployment of new hardware or a new process. When results are USED the site problem holders become “users”. The important aspect that research results are to be used is captured …
Date: July 31, 2003
Creator: Josephson, Gary B. & Hale, Donna
System: The UNT Digital Library
Multi-strange baryon production in Au-Au collisions at sqrt(sNN) = 130 GeV (open access)

Multi-strange baryon production in Au-Au collisions at sqrt(sNN) = 130 GeV

The transverse mass spectra and mid-rapidity yields for {Xi}s and {Omega}s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to {pi}, K, p and {Lambda}s.
Date: July 31, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Voluntary agreements in the industrial sector in China (open access)

Voluntary agreements in the industrial sector in China

China faces a significant challenge in the years ahead to continue to provide essential materials and products for a rapidly-growing economy while addressing pressing environmental concerns. China's industrial sector is heavily dependent on the country's abundant, yet polluting, coal resources. While tremendous energy conservation and environmental protection achievements were realized in the industrial sector in the past, there remains a great gulf between the China's level of energy efficiency and that of the advanced countries of the world. Internationally, significant energy efficiency improvement in the industrial sector has been realized in a number of countries using an innovative policy mechanism called Voluntary Agreements. This paper describes international experience with Voluntary Agreements in the industrial sector as well as the development of a pilot program to test the use of such agreements with two steel mills in Shandong Province, China.
Date: March 31, 2003
Creator: Price, Lynn; Worrell, Ernst & Sinton, Jonathan
System: The UNT Digital Library
Effects of controlled dog hunting on movements of female white-tailed deer. (open access)

Effects of controlled dog hunting on movements of female white-tailed deer.

D'Angelo, Gino, J., John C. Kilgo, Christopher E. Comer, Cory D. Drennan, David A. Osborn, and Karl V. Miller. 2003. Effects of controlled dog hunting on movements of female white-tailed deer. In: Proceedings of the Annu. Conf. Southeast. Assoc. Fish and Wildl. Agencies. 57:317-325. This article explores the relationship between controlled dog hunting and the movements of female white tailed deer at the Savannah River Site, South Carolina. The data suggests that short term, controlled dog hunting has little long-term effect on adult, female white-tailed deer movement on the Savannah River Site.
Date: December 31, 2003
Creator: D'Angelo, Gino, J.; Kilgo, John, C.; Comer, Christopher, E.; Drennan, Cory, D.; Osborn, David, A. & Miller, Karl, V.
System: The UNT Digital Library
Temporal development of the plasma composition of Zr and Cr metal plasma streams in a N2 environment (open access)

Temporal development of the plasma composition of Zr and Cr metal plasma streams in a N2 environment

We describe the temporal development of the plasma composition in a pulsed plasma stream generated by cathodic arc. Cathodes of Zr and Cr were operated at various nitrogen pressures. The time resolved plasma composition for the cathode materials was analyzed with time-of-flight charge-to-mass spectrometry, and was found to be a strong function of the nitrogen pressure. Large plasma composition gradients were detected within the first 60 {micro}s of the pulse, the nitrogen ion concentration increasing with increasing pressure. The results are explained by the formation and erosion of a compound layer formed at the cathode surface in the presence of a reactive gas. The average charge state was also found to be affected by the reactive gas pressure as well as by the time after ignition. The charge states were highest in the beginning of the pulse at low nitrogen pressure, decreasing to a steady-state value at higher pressure. These results are of importance for reactive plasma processing and for controlling of the evolution of thin film composition and microstructure.
Date: January 31, 2003
Creator: Rosen, Johanna; Anders, Andre; Hultman, Lars & Schneider, Jochen M.
System: The UNT Digital Library
Implosion of indirectly driven reentrant cone shell target (open access)

Implosion of indirectly driven reentrant cone shell target

In an x-ray driven reentrant cone fast ignition target the x-ray spectrum contains a high energy component that casuses preheating of the reentrant cone and mixing of the gold into the collapsing shell. Direct laser drive might avoid this problem.
Date: October 31, 2003
Creator: Stephens, R. B.; Hatchett, S. P.; Turner, R. E.; Tanaka, K. A. & Kodama, R.
System: The UNT Digital Library
Stochastically generating tree diameter lists to populate forest stands based on the linkage variables, forest type and stand age. (open access)

Stochastically generating tree diameter lists to populate forest stands based on the linkage variables, forest type and stand age.

Forest inventory data were used to develop a stand-age-driven, stochastic predictor of unit-area, frequency-weighted lists of breast high tree diameters (DBH). The average of mean statistics from 40-simulation prediction sets of an independent 78-plot validation dataset differed from the observed validation means by 0.5 cm for DBH, and by 12 trees/h for density. The 40-simulation average of standard deviation, quartile range, maximum value and minimum value differed from the validation dataset, respectively, by 0.3, 1.3, 0.6 and 1.5 cm for DBH, and 10, 42, 29, and 54 trees/h for density. In addition, test statistics were also computed individually for each of the 40 single simulations of the 78-plot validation dataset. In all cases, the test statistics supported the null hypothesis of no difference between simulated and observed DBH lists. When power of these hypothesis test statistics was set to 80%, the calculated minimum detectable differences were still reasonably small at 2.7 cm for mean DBH and 90 trees/h for stocking. Also, the shape and dispersion of simulated mean-DBH/density scatter graphs were similar to the same scatter graph from the observed, validation dataset.
Date: August 31, 2003
Creator: Parresol, B. R. & Lloyd, F. T.
System: The UNT Digital Library
Annotating animal mitochondrial tRNAs: A new scoring scheme and an empirical evaluation of four methods (open access)

Annotating animal mitochondrial tRNAs: A new scoring scheme and an empirical evaluation of four methods

Identification of transfer RNAs in animal mitochondrial genomes is important for many areas of genome analysis including phylogenetic reconstruction, understanding inheritance of disease, and identifying forensic materials. Animal mitochondrial tRNAs differ from the canonical tRNAs in both their secondary structure and level of conservation of nucleotide sequence and therefore, conventional tRNA or general RNA searching software cannot be used for identification and custom methods are required. Here we present the results of an experimental analysis of four different methods tested on a large dataset consisting of 5,720 tRNAs extracted from the entire set of complete animal mitochondrial genomes in GenBank. Methods were evaluated based on number of false negatives and false positives. Additionally, we present a new scoring scheme customized for animal mitochondrial tRNAs.
Date: December 31, 2003
Creator: Wyman, Stacia K. & Boore, Jeffrey L.
System: The UNT Digital Library
Compact neutron generator development at LBNL (open access)

Compact neutron generator development at LBNL

A wide variety of applications ranging from medical (BNCT, Boron Neutron Capture Therapy) and basic science (neutron imaging, material studies) to homeland security (explosive detection and nuclear material non-proliferation) are in need of compact, high flux neutron generators. The Plasma and Ion Source Technology Group in the Lawrence Berkeley National Laboratory is developing various neutron generators for these applications. These neutron generators employed either the D-D or the D-T fusion reaction for the neutron production. The deuterium or deuterium-tritium gas mixture is ionized in an RF-driven plasma source. The ions are then accelerated to {approx}100 keV energy using high current, high voltage DC-power supply to a target where the 2.45 MeV (for D-D reaction) or 14 MeV (for the D-T reaction) neutrons are generated. The development of two different types of neutron tubes are being discussed in this presentation, namely compact, pulsed operation neutron generators and cw, high yield neutron generators. These generators are currently operating at D-D neutron yields of 108 n/s and 109 n/s respectively. A facility, incorporating the larger neutron generator, has been constructed for Prompt Gamma Activation Analysis (PGAA) and Neutron Activation Analysis (NAA) measurements.
Date: December 31, 2003
Creator: Reijonen, J.; English, G.; Firestone, R.; Giquel, F.; King, M.; Leung, K. N. et al.
System: The UNT Digital Library
Masses, lifetimes, and decays of B hadrons at the Tevatron (open access)

Masses, lifetimes, and decays of B hadrons at the Tevatron

The latest results in B physics from the CDF and D0 experiments at the Tevatron are presented, including inclusive b lifetime measurement, exclusive lifetime measurement of the B{sub s}. Promising samples collected by CDF with its Secondary Vertex Trigger are shown as well.
Date: October 31, 2003
Creator: Vacavant, L.
System: The UNT Digital Library
Matching the Capabilities of Higher Education Institutions with the Technology Needs of the Y-12 National Security Complex (open access)
Effect of immiscible liquid contaminants on P-wave transmission through natural aquifer samples (open access)

Effect of immiscible liquid contaminants on P-wave transmission through natural aquifer samples

We performed core-scale laboratory experiments to examine the effect of non-aqueous phase liquid (NAPL) contaminants on P-wave velocity and attenuation in heterogeneous media. This work is part of a larger project to develop crosswell seismic methods for minimally invasive NAPL detection. The test site is the former DOE Pinellas Plant in Florida, which has known NAPL contamination in the surficial aquifer. Field measurements revealed a zone of anomalously high seismic attenuation, which may be due to lithology and/or contaminants (NAPL or gas phase). Intact core was obtained from the field site, and P-wave transmission was measured by the pulse-transmission technique with a 500 kHz transducer. Two types of samples were tested: a clean fine sand from the upper portion of the surficial aquifer, and clayey-silty sand with shell fragments and phosphate nodules from the lower portion. Either NAPL trichloroethene or toluene was injected into the initially water-saturated sample. Maximum NAPL saturations ranged from 30 to 50% of the pore space. P-wave velocity varied by approximately 4% among the water-saturated samples, while velocities decreased by 5 to 9% in samples at maximum NAPL saturation compared to water-saturated conditions. The clay and silt fraction as well as the larger scatterers in the …
Date: January 31, 2003
Creator: Geller, Jil T.; Ajo-Franklin, Jonathan B. & Majer, Ernest L.
System: The UNT Digital Library
Results on intense beam focusing and neutralization from the neutralized beam experiment (open access)

Results on intense beam focusing and neutralization from the neutralized beam experiment

We have demonstrated experimental techniques to provide active neutralization for space-charge dominated beams as well as to prevent uncontrolled ion beam neutralization by stray electrons. Neutralization is provided by a localized plasma injected from a cathode arc source. Unwanted secondary electrons produced at the wall by halo particle impact are suppressed using a radial mesh liner that is positively biased inside a beam drift tube. We present measurements of current transmission, beam spot size as a function of axial position, beam energy and plasma source conditions. Detailed comparisons with theory are also presented.
Date: October 31, 2003
Creator: Roy, P. K.; Yu, S. S.; Eylon, S.; Henestroza, E.; Anders, A.; Bieniosek, F. M. et al.
System: The UNT Digital Library
B and c quark production at CDF, {radical} s = 1.96 TeV (open access)

B and c quark production at CDF, {radical} s = 1.96 TeV

Measurements of heavy quark production at the Tevatron have previously shown discrepancies with theoretical predictions. The increased luminosity of Run 2 will allow CDF to investigate b and c quark production more precisely. In this review three measurements, based on a subset of current data are presented: charm meson production; J/{psi} production; production of an energetic photon in conjunction with a b or c quark jet.
Date: October 31, 2003
Creator: Shears, T.
System: The UNT Digital Library
Hard QCD at the Tevatron (open access)

Hard QCD at the Tevatron

Results from QCD studies at the Tevatron from new Run 2 data are presented. The inclusive jet cross section and dijet mass spectrum are measured at {radical}s = 1960 GeV by the CDF and D0 collaborations. CDF also reports results of searches for new particles decaying into dijets, and a study of jet shapes.
Date: October 31, 2003
Creator: Mesropian, C.
System: The UNT Digital Library
Evolutionary conservation of regulatory elements in vertebrate HOX gene clusters (open access)

Evolutionary conservation of regulatory elements in vertebrate HOX gene clusters

Due to their high degree of conservation, comparisons of DNA sequences among evolutionarily distantly-related genomes permit to identify functional regions in noncoding DNA. Hox genes are optimal candidate sequences for comparative genome analyses, because they are extremely conserved in vertebrates and occur in clusters. We aligned (Pipmaker) the nucleotide sequences of HoxA clusters of tilapia, pufferfish, striped bass, zebrafish, horn shark, human and mouse (over 500 million years of evolutionary distance). We identified several highly conserved intergenic sequences, likely to be important in gene regulation. Only a few of these putative regulatory elements have been previously described as being involved in the regulation of Hox genes, while several others are new elements that might have regulatory functions. The majority of these newly identified putative regulatory elements contain short fragments that are almost completely conserved and are identical to known binding sites for regulatory proteins (Transfac). The conserved intergenic regions located between the most rostrally expressed genes in the developing embryo are longer and better retained through evolution. We document that presumed regulatory sequences are retained differentially in either A or A clusters resulting from a genome duplication in the fish lineage. This observation supports both the hypothesis that the conserved …
Date: December 31, 2003
Creator: Santini, Simona; Boore, Jeffrey L. & Meyer, Axel
System: The UNT Digital Library
High-resolution NMR of anisotropic samples with spinning away from the magic angle (open access)

High-resolution NMR of anisotropic samples with spinning away from the magic angle

High-resolution NMR of samples in the solid state is typically performed under mechanical sample spinning around an axis that makes an angle, called the magic angle, of 54.7 degrees with the static magnetic field. There are many cases in which geometrical and engineering constraints prevent spinning at this specific angle. Implementations of in-situ and ex-situ magic angle field spinning might be extremely demanding because of the power requirements or an inconvenient sample size or geometry. Here we present a methodology based on switched angle spinning between two angles, none of which is the magic angle, which provide both isotropic and anisotropic information. Using this method, named Projected Magic Angle Spinning, we were able to obtain resolved isotropic chemical shifts in spinning samples where the broadening is mostly inhomogeneous.
Date: March 31, 2003
Creator: Sakellariou, Dimitris; Meriles, Carlos A.; Martin, Rachel W. & Pines, Alexander
System: The UNT Digital Library
Pion-Kaon correlations in central Au+Au collisions at {radical}(s{sub NN}) = 130 GeV (open access)

Pion-Kaon correlations in central Au+Au collisions at {radical}(s{sub NN}) = 130 GeV

No abstract prepared.
Date: July 31, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Extruding plastic scintillator at Fermilab (open access)

Extruding plastic scintillator at Fermilab

An understanding of the costs involved in the production of plastic scintillators and the development of a less expensive material have become necessary with the prospects of building very large plastic scintillation detectors. Several factors contribute to the high cost of plastic scintillating sheets, but the principal reason is the labor-intensive nature of the manufacturing process. In order to significantly lower the costs, the current casting procedures had to be abandoned. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. This concept was tested and high quality extruded plastic scintillator was produced. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. This paper will discuss the characteristics of extruded plastic scintillator and its raw materials, the different manufacturing techniques and the current R&D program at Fermilab.
Date: October 31, 2003
Creator: Pla-Dalmau, Anna; Bross, Alan D. & Rykalin, Victor V.
System: The UNT Digital Library
Netest: A Tool to Measure the Maximum Burst Size, Available Bandwidth and Achievable Throughput (open access)

Netest: A Tool to Measure the Maximum Burst Size, Available Bandwidth and Achievable Throughput

Distinguishing available bandwidth and achievable throughput is essential for improving network applications' performance. Achievable throughput is the throughput considering a number of factors such as network protocol, host speed, network path, and TCP buffer space, where as available bandwidth only considers the network path. Without understanding this difference, trying to improve network applications' performance is like ''blind men feeling the elephant'' [4]. In this paper, we define and distinguish bandwidth and throughput, and debate which part of each is achievable and which is available. Also, we introduce and discuss a new concept - Maximum Burst Size that is crucial to the network performance and bandwidth sharing. A tool, netest, is introduced to help users to determine the available bandwidth, and provides information to achieve better throughput with fairness of sharing the available bandwidth, thus reducing misuse of the network.
Date: January 31, 2003
Creator: Jin, Guojun & Tierney, Brian
System: The UNT Digital Library
Corrosion of Exhaust and Filtration Equipment in a Radioactive Waste Incinerator (open access)

Corrosion of Exhaust and Filtration Equipment in a Radioactive Waste Incinerator

Condensation in the exhaust gas system of an incinerator burning low activity radioactive wastes led to numerous corrosion developments and rapid failure of the discharge filters. The problem was traced to insufficient reheat of the exhaust gases following scrubbing. Rust particulate and moisture loaded the filters, leading to water accumulation, chloride cracking of the filter housings, and plugging and tearing of the filter media itself. To mitigate the problem, the exhaust gas temperature was increased, thermal insulation was installed on the ductwork, and the interiors of the ducts and new filter housings were lined with a protective coating.
Date: October 31, 2003
Creator: Jenkins, C. F.
System: The UNT Digital Library
Quantifying the Contribution of Lubrication Oil Carbon to Particulate Emissions from a Diesel Engine (open access)

Quantifying the Contribution of Lubrication Oil Carbon to Particulate Emissions from a Diesel Engine

The contribution of lubrication oil to particulate matter (PM) emissions from a Cummins B5.9 Diesel engine was measured using accelerator mass spectrometry to trace carbon isotope concentrations. The engine operated at fixed medium load (285 N-m (210 ft.lbs.) at 1600 rpm) used 100% biodiesel fuel (8100) with a contemporary carbon-14 ({sup 14}C) concentration of 103 amol {sup 14}C mg C. The {sup 14}C concentration of the exhaust CO{sub 2} and PM were 102 and 99 amol {sup 14}C/mg C, respectively. The decrease in {sup 14}C content in the CO, and PM are due to the consumption of lubrication oil which is {sup 14}C-free. Approximately 4% of the carbon in PM came from lubrication oil under these operating conditions.
Date: January 31, 2003
Creator: Buchholz, B. A.; Dibble, R. W.; Rich, D. & Cheng, A. S.
System: The UNT Digital Library
Atomistic modeling of diffusional phasetransformations with elastic strain (open access)

Atomistic modeling of diffusional phasetransformations with elastic strain

Phase transformations in 2xxx series aluminium alloys (Al-Cu-Mg) are investigated with an off-lattice atomistic kinetic Monte Carlo simulation incorporating the effects of strain around misfitting atoms and vacancies. Atomic interactions are modelled by Finnis-Sinclair potentials constructed for these simulations. Vacancy diffusion is modelled by comparing the energies of trial states, where the system is partially relaxed for each trial state. No special requirements are made about the description of atomic interactions, making our approach suitable for more fundamentally based models such as tight binding if sufficient computational resources are available. Only a limited precision is required for the energy of each trial state, determined by the value of kBT. Since the change in the relaxation displacement field caused by a vacancy hop decays as 1/r{sup 3} , it is sufficient to determine the next move by relaxing only those atoms in a sphere of finite radius centred on the moving vacancy. However, once the next move has been selected, the entire system is relaxed. Simulations of the early stages of phase separation in Al-Cu with elastic relaxation show an enhanced rate of clustering compared to those performed on the same system with a rigid lattice.
Date: October 31, 2003
Creator: Mason, D R; Rudd, R E & Sutton, A P
System: The UNT Digital Library