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DEFLAGRATION-TO-DETONATION TRANSITION IN LX-04 AS A FUNCTION OF LOADING DENSITY, TEMPERATURE, AND CONFINEMENT (open access)

DEFLAGRATION-TO-DETONATION TRANSITION IN LX-04 AS A FUNCTION OF LOADING DENSITY, TEMPERATURE, AND CONFINEMENT

The potential for deflagration-to-detonation transition (DDT) in LX-04 (85/15 HMX/Viton) is being evaluated as a function of loading density, temperature, and confinement. In the high confinement arrangement, a matrix of tests will be performed with the LX-04 loaded at {approx}50, 70, 90, and {approx}99 %TMD; and temperatures of ambient, 160 C, and 190 C, at each loading density. A more limited set of tests at medium confinement will be conducted. As expected, LX-04 does not undergo DDT at near TMD loadings in both medium and high confinement, although the later still results in significant fragmentation. In high confinement at pour density (50.3 %TMD), LX-04 does not transit to detonation at 160 C, but does at ambient and 190 C with the shortest run distance to detonation (l) at ambient temperature. With a 70% TMD loading at ambient temperature, l was even less. The limited ambient temperature measurements for l in high confinement are similar to previous data for 91/9 HMX/wax, which has nearly the same %volume of HMX as LX-04.
Date: June 1, 2005
Creator: Sandusky, Harold W.; Granholm, Richard H.; Bohl, Douglas G.; Hare, David E.; Vandersall, Kevin S. & Garcia, Frank
System: The UNT Digital Library
ON-SHELL IMPROVEMENT OF THE MASSIVE WILSON QUARK ACTION. (open access)

ON-SHELL IMPROVEMENT OF THE MASSIVE WILSON QUARK ACTION.

We review a relativistic approach to the heavy quark physics in lattice QCD by applying a relativistic O(a) improvement to the massive Wilson quark action on the lattice. After explaining how power corrections of m{sub Q}a can be avoided and remaining uncertainties are reduced to be of order (a{Lambda}{sub QCD}){sup 2}, we demonstrate a determination of four improvement coefficients in the action up to one-loop level in a mass dependent way. We also show a perturbative determination of mass dependent renormalization factors and O(a) improvement coefficients for the vector and axial vector currents. Some preliminary results of numerical simulations are also presented.
Date: April 1, 2005
Creator: Aoki, S.; Kayaba, Y.; Kuramiashi, Y. & Yamada, N.
System: The UNT Digital Library
On the origin of microcraters on the surface of ion beam bombardedplant cell walls (open access)

On the origin of microcraters on the surface of ion beam bombardedplant cell walls

Ion bombardment of plant and bacterial cellular material has recently been used as a tool for the transfer of exogenous DNA macromolecules into the cell interior region. The precise mechanism that leads to the transfer of macromolecules through the cell envelope is not yet clear, however it has been observed that the ion bombardment is accompanied by the formation of ''microcraters'' on the cell wall, and it is possible that these features provide channels for the macromolecule transfer. Thus the nature and origin of the microcraters is of importance to understanding the DNA transfer phenomenon as well as being of fundamental interest. We report here on some scanning electron microscope observations we have made of onion skin cells that have been subjected to electron beam bombardment of sufficiently high power density to damage the cell wall. The damage seen is much less than and different from the microcraters formed subsequent to ion bombardment. We speculate that the microcraters may originate from the explosive release of gas generated in the biomaterial by ion bombardment.
Date: June 1, 2005
Creator: Salvadori, M. C.; Teixeira, F. S. & Brown, I. G.
System: The UNT Digital Library
Application of deuteron-deuteron (d-d) fusion neutrons to 40ar/39/ar geochronology (open access)

Application of deuteron-deuteron (d-d) fusion neutrons to 40ar/39/ar geochronology

This report talks about Application of deuteron-deuteron (d-d) fusion neutrons to 40ar/39/ar geochronology
Date: January 1, 2005
Creator: Renne, P.; Knight, K. B.; Nomade, S.; Leung, K. N. & Lou, T. P.
System: The UNT Digital Library
Analytical Methodologies for Detection of Gamma-Valerolactone, Delta-Valerolactone, Acephate and Azinphos Methyl and Their Associated Metabolites in Complex Biological Matrices (open access)

Analytical Methodologies for Detection of Gamma-Valerolactone, Delta-Valerolactone, Acephate and Azinphos Methyl and Their Associated Metabolites in Complex Biological Matrices

Non-invasive biomonitoring for chemicals of interest in law enforcement and similar monitoring of pesticides, together with their metabolites, can not only save money but can lead to faster medical attention for individuals exposed to these chemicals. This study describes methods developed for the analysis of gamma-valerolactone (GVL), delta-valerolactone (DVL), acephate, and azinphos methyl in saliva and serum. Liquid chromatography/mass spectrometry (LC/MS) operated in the negative and positive ion mode and gas chromatography/mass spectrometry (GC/MS) were used to analyze GVL and DVL. Although both analytical techniques worked well, lower detection limits were obtained with GC/MS. The lactones and their corresponding sodium salts were spiked into both saliva and serum. The lactones were isolated from saliva or serum using newly developed extraction techniques and then subsequently analyzed using GC/MS. The sodium salts of the lactones are nonvolatile and require derivatization prior to analysis by this method. N-methyl-N-(t-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) was ultimately selected as the reagent for derivatization because the acidic conditions required for reactions with diazomethane caused the salts to undergo intramolecular cyclization to the corresponding lactones. In vitro studies were conducted using rat liver microsomes to determine other metabolites associated with these compounds. Azinphos methyl and acephate are classified as organophosphate pesticides, …
Date: January 1, 2005
Creator: Zink, Erica; Clark, Ryan; Grant, Karen; Campbell, James & Hoppe, Erik
System: The UNT Digital Library
Arsenic Sulfide Nanowire Formation on Fused Quartz Surfaces (open access)

Arsenic Sulfide Nanowire Formation on Fused Quartz Surfaces

Arsenic sulfide (AsxSy) nanowires were synthesized by an evaporation-condensation process in evacuated fused quartz ampoules. During the deposition process, a thin, colored film of AsxSy was deposited along the upper, cooler portion of the ampoule. The ampoule was sectioned and the deposited film analyzed using scanning electron microscopy (SEM) to characterize and semi-quantitatively evaluate the microstructural features of the deposited film. A variety of microstructures were observed that ranged from a continuous thin film (warmer portion of the ampoule), to isolated micron- and nano-scale droplets (in the intermediate portion), as well as nanowires (colder portion of the ampoule). Experiments were conducted to evaluate the effects of ampoule cleaning methods (e.g. modify surface chemistry) and quantity of source material on nanowire formation. The evolution of these microstructures in the thin film was determined to be a function of initial pressure, substrate temperature, substrate surface treatment, and initial volume of As2S3 glass. In a set of two experiments where the initial pressure, substrate thermal gradient, and surface treatment were the same, the initial quantity of As2S3 glass per internal ampoule volume was doubled from one test to the other. The results showed that AsxSy nanowires were only formed in the test with …
Date: January 1, 2005
Creator: Olmstead, J.; Riley, B. J.; Johnson, B. R. & Sundaram, S. K.
System: The UNT Digital Library
A Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors (open access)

A Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors

We have performed a search for bursts of gravitational waves associated with the very bright Gamma Ray Burst GRB030329, using the two detectors at the LIGO Hanford Observatory. Our search covered the most sensitive frequency range of the LIGO detectors (approximately 80-2048 Hz), and we specifically targeted signals shorter than {approx_equal}150 ms. Our search algorithm looks for excess correlated power between the two interferometers and thus makes minimal assumptions about the gravitational waveform. We observed no candidates with gravitational wave signal strength larger than a pre-determined threshold. We report frequency dependent upper limits on the strength of the gravitational waves associated with GRB030329. Near the most sensitive frequency region, around {approx_equal}250 Hz, our root-sum-square (RSS) gravitational wave strain sensitivity for optimally polarized bursts was better than h{sub RSS} {approx_equal} 6 x 10{sup -21} Hz{sup -1/2}. Our result is comparable to the best published results searching for association between gravitational waves and GRBs.
Date: January 1, 2005
Creator: Abbott, B.; Abbott, R.; Adhikari, R.; Ageev, A.; Allen, B.; Amin, R. et al.
System: The UNT Digital Library
Observation of parity violation in the Omega- ---> Lambda K- decay (open access)

Observation of parity violation in the Omega- ---> Lambda K- decay

The {alpha} decay parameter in the process {Omega}{sup -} {yields} {Lambda}K{sup -} has been measured from a sample of 4.50 million unpolarized {Omega}{sup -} decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [1.78 {+-} 0.19(stat) {+-} 0.16(syst)] x 10{sup -2}. This is the first unambiguous evidence for a nonzero {alpha} decay parameter, and hence parity violation, in the {Omega}{sup -} {Lambda}K{sup -} decay.
Date: May 1, 2005
Creator: Lu, L. C.; U., /Virginia; Burnstein, R. A.; Chakravorty, A.; Chen, Y. C.; Choong, W.-S. et al.
System: The UNT Digital Library
Evidence for the decay Sigma+ ---> p mu+ mu- (open access)

Evidence for the decay Sigma+ ---> p mu+ mu-

We report the first evidence for the decay {Sigma}{sup +} {yields} p{mu}{sup +}{mu}{sup -} from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ratio is {Beta}({Sigma}{sup +} {yields} p{mu}{sup +}{mu}{sup -}) = [8.6{sub -5.4}{sup +6.6}(stat) {+-} 5.5(syst)] x 10{sup -8}. The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, {Sigma}{sup +} {yields} pP{sup 0},P{sup 0} {yields} {mu}{sup +}{mu}{sup -} with a P{sup 0} mass of 214.3 {+-} 0.5 MeV/c{sup 2} and branching ratio {Beta}({Sigma}{sup +} {yields} pP{sup 0}, P{sup 0} {yields} {mu}{sup +}{mu}{sup -}) = [3.1{sub -1.9}{sup +2.4}(stat) {+-} 1.5(syst)] x 10{sup -8}.
Date: January 1, 2005
Creator: Park, HyangKyu; U., /Michigan; Burnstein, R. A.; Chakravorty, A.; Chen, Y. C.; Choong, W. S. et al.
System: The UNT Digital Library
Search for Delta S = 2 nonleptonic hyperon decays (open access)

Search for Delta S = 2 nonleptonic hyperon decays

A sensitive search for the rare decays {Omega}{sup -} {yields} {Lambda}{pi}{sup -} and {Xi}{sup 0} {yields} p{pi}{sup -} has been performed using data from the 1997 run of the HyperCP (Fermilab E871) experiment. Limits on other such processes do not exclude the possibility of observable rates for |{Delta}S| = 2 nonleptonic hyperon decays, provided the decays occur through parity-odd operators. They obtain the branching-fraction limits {Beta}({Omega}{sup -} {yields} {Lambda}{pi}{sup -}) < 2.9 x 10{sup -6} and {Beta}({Xi}{sup 0} {yields} p{pi}{sup -}) < 8.2 x 10{sup -6}, both at 90% confidence level.
Date: March 1, 2005
Creator: White, C. G.; /IIT, Chicago; Burnstein, R. A.; Chakravorty, A.; Chan, A.; Chen, Y. C. et al.
System: The UNT Digital Library
Search for the lepton-number-violating decay Xi- ---> p mu- mu- (open access)

Search for the lepton-number-violating decay Xi- ---> p mu- mu-

None
Date: May 1, 2005
Creator: Rajaram, D.; Burnstein, R. A.; Chakravorty, A.; Chan, A.; Chen, Y. C.; Choong, W. S. et al.
System: The UNT Digital Library
Measurement of the alpha asymmetry parameter for the Omega- ---> Lambda K- decay (open access)

Measurement of the alpha asymmetry parameter for the Omega- ---> Lambda K- decay

None
Date: February 1, 2005
Creator: Chen, Y. C.; /Taiwan, Inst. Phys.; Burnstein, R. A.; Chakravorty, A.; Chan, A.; Choong, W. S. et al.
System: The UNT Digital Library
Measurement of the p - anti-p ---> W gamma + X cross section at s**(1/2) = 1.96-TeV and WW gamma anomalous coupling limits (open access)

Measurement of the p - anti-p ---> W gamma + X cross section at s**(1/2) = 1.96-TeV and WW gamma anomalous coupling limits

The WW{gamma} triple gauge boson coupling parameters are studied using p{bar p} {yields} {ell}{nu}{gamma} + X({ell} = e, {mu}) events at {radical}s = 1.96 TeV. The data were collected with the D0 detector from an integrated luminosity of 162 pb{sup -1} delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for p{bar p} {yields} W({gamma}) + X {yields} {ell}{nu}{gamma} + X with E{sub T}{sup {gamma}} > 8 GeV and {Delta}R{sub {ell}{gamma}} > 0.7 is 14.8 {+-} 1.6(stat) {+-} 1.0(syst) {+-} 1.0(lum) pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88 < {Delta}{kappa}{sub {gamma}} < 0.96 and -0.20 < {lambda}{sub {gamma}} < 0.20.
Date: March 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for single top quark production in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for single top quark production in p anti-p collisions at s**(1/2) = 1.96-TeV

We present a search for electroweak production of single top quarks in the s-channel and t-channel using neural networks for signal-background separation. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy of 1.96 TeV and find no evidence for a single top quark signal. The resulting 95% confidence level upper limits on the single top quark production cross sections are 6.4 pb in the s-channel and 5.0 pb in the t-channel.
Date: May 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
The Upgraded D0 detector (open access)

The Upgraded D0 detector

The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.
Date: July 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, D. L.; Adams, M. et al.
System: The UNT Digital Library
The Sloan Digital Sky Survey Quasar Catalog. 3. Third data release (open access)

The Sloan Digital Sky Survey Quasar Catalog. 3. Third data release

We present the third edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of the 46,420 objects in the SDSS Third Data Release that have luminosities larger than M{sub i} = -22 (in a cosmology with H{sub 0} = 70 km s{sup -1} Mpc{sup -1}, {Omega}{sub M} = 0.3, and {Omega}{sub {Lambda}} = 0.7), have at least one emission line with FWHM larger than 1000 km s{sup -1} or are unambiguously broad absorption line quasars, are fainter than i = 15.0, and have highly reliable redshifts. The area covered by the catalog is {approx} 4188 deg{sup 2}. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.47; the high-redshift sample includes 520 quasars at redshifts greater than four, of which 17 are at redshifts greater than five. For each object the catalog presents positions accurate to better than 0.2'' rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200 at a spectral resolution …
Date: March 1, 2005
Creator: Schneider, Donald P.; Hall, Patrick B.; Richards, Gordon T.; Vanden Berk, Daniel E.; Anderson, Scott F.; Fan, Xiao-Hui et al.
System: The UNT Digital Library
Time dependant quantum efficiency and dark current measurements in an RF photocathode injector with a high quantum efficiency cathode (open access)

Time dependant quantum efficiency and dark current measurements in an RF photocathode injector with a high quantum efficiency cathode

Studies of photo-emission and field emission behavior in an RF gun have been carried out. Unexpected phenomena were observed. In situ changes in the cathode's quantum efficiency and dark current with time were seen during operation of the photo-injector. These changes were correlated with the magnetostatic field at the cathode. In addition, multipacting has been observed under certain conditions. Recent measurements indicate a correlation between multipacting and anomalous photo- and field emission behavior.
Date: May 1, 2005
Creator: Fliller, R. P., III; Edwards, H. & Hartung, W.
System: The UNT Digital Library
Use of Lasers to Study the Impact of Fractionation and Condensation on the Toxicity of Nuclear Weapon Fallout (open access)

Use of Lasers to Study the Impact of Fractionation and Condensation on the Toxicity of Nuclear Weapon Fallout

An experimental concept has been developed to collect data to aid in the refinement of simulation programs designed to predict the fallout effects arising from surface and shallowly buried nuclear weapon detonations. These experiments, called the Condensation Debris Experiments (CDE), are intended to study the condensation/fractionation of material that is liberated following an initial deposition of laser energy onto a small, characterized target. The CDE effort also encompasses target development and material studies as well as supporting computational efforts studying radiation hydrodynamics, computational fluid dynamics, and relevant neutron activation processes (not discussed here).
Date: April 1, 2005
Creator: Vidnovic, T., III; Bradley, K. S.; Debonnel, C. S.; Dipeso, G.; Fournier, K.; Karpenko, V. P. et al.
System: The UNT Digital Library
Absolute X-Ray Yields from Laser-Irradiated, Ge-doped Aerogel Targets (open access)

Absolute X-Ray Yields from Laser-Irradiated, Ge-doped Aerogel Targets

None
Date: July 1, 2005
Creator: Fournier, K. B.; Tobin, M.; Poco, J. F.; Bradley, K.; Coverdale, C. A.; Beutler, D. et al.
System: The UNT Digital Library
Dopants and Defects in InN and InGaN Alloys (open access)

Dopants and Defects in InN and InGaN Alloys

We have performed systematic studies of the effects of high-energy particle irradiation on the properties of InGaN alloys. In agreement with the amphoteric defect model, irradiation of InN produces donor-like defects. The electron concentration increases with increasing radiation dose and saturates at 4 x 10{sup 20} cm{sup -3} at very high doses. We find that the increase of the electron concentration causes a large blue-shift of the absorption edge, which is well-explained by the Burstein-Moss effect. The maximum electron concentration decreases with increasing Ga fraction in irradiated In{sub 1-x}Ga{sub x}N alloys as the conduction band edge approaches the Fermi level stabilization energy (E{sub FS}). For x > 0.66 the conduction band edge moves above E{sub FS} and the irradiation of n-type films produces acceptor-like defects, resulting in a reduced free electron concentration. An analysis of the concentration dependence of the electron mobility in InN indicates that the dominant defects in irradiated InN are triply-charged donors. Finally, we show that InN films doped with Mg acceptors behave like undoped films above a threshold radiation dose.
Date: April 1, 2005
Creator: Walukiewicz, W.; Jones, R. E.; Li, S. X.; Yu, K. M.; Ager, J. W., III; Haller, E. E. et al.
System: The UNT Digital Library
Direct-Write Contacts for Solar Cells (open access)

Direct-Write Contacts for Solar Cells

We report on our project to develop inkjet printable contacts for solar cells. Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. Thick, highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and PCB have been printed at 100-200 C in air and N2, respectively. Ag grids were inkjet-printed on Si solar cells and fired through silicon nitride AR layer at 850 C resulting in 8% cells. Next-generation multicomponent inks (including etching agents) have also been developed with improved fire-through contacts leading to higher cell efficiencies. The approach developed can be easily extended to other conductors such as Pt, Pd, and Au, etc. In addition, PEDOT-PSS polymer-based conductors were inkjet-printed with the conductivity as good or better than those of polymer-based conductors.
Date: January 1, 2005
Creator: Kaydanova, T.; van Hest, M. F. A. M.; Miedaner, A.; Curtis, C. J.; Alleman, J. L.; Dabney, M. S. et al.
System: The UNT Digital Library
Proposed Route to Thin Film Crystal Si Using Biaxially Textured Foreign Template Layers (open access)

Proposed Route to Thin Film Crystal Si Using Biaxially Textured Foreign Template Layers

We have developed a new approach to growing photovoltaic-quality crystal silicon (c-Si) films on glass. Other approaches to film c-Si focus on increasing grain size in order to reduce the deleterious effects of grain boundaries. Instead, we have developed an approach to align the silicon grains biaxially (both in and out of plane) so that 1) grain boundaries are "low-angle" and have less effect on the electronic properties of the material and 2) subsequent epitaxial thickening is simplified. They key to our approach is the use of a foreign template layer that can be grown with biaxial texture directly on glass.
Date: November 1, 2005
Creator: Teplin, C. W.; Ginley, D. S.; van Hest, M. F. A. M.; Perkins, J. D.; Young, D. L.; Stradins, P. et al.
System: The UNT Digital Library
X-Ray Imaging Of Cryogenic Deuterium-Tritium Layers In A Beryllium Shell (open access)

X-Ray Imaging Of Cryogenic Deuterium-Tritium Layers In A Beryllium Shell

None
Date: June 1, 2005
Creator: Kozioziemski, B. J.; Sater, J. D.; Moody, J. D.; Sanchez, J. J.; London, R. A.; Barty, A. et al.
System: The UNT Digital Library