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A fast contour descriptor algorithm for supernova imageclassification (open access)

A fast contour descriptor algorithm for supernova imageclassification

We describe a fast contour descriptor algorithm and its application to a distributed supernova detection system (the Nearby Supernova Factory) that processes 600,000 candidate objects in 80 GB of image data per night. Our shape-detection algorithm reduced the number of false positives generated by the supernova search pipeline by 41% while producing no measurable impact on running time. Fourier descriptors are an established method of numerically describing the shapes of object contours, but transform-based techniques are ordinarily avoided in this type of application due to their computational cost. We devised a fast contour descriptor implementation for supernova candidates that meets the tight processing budget of the application. Using the lowest-order descriptors (F{sub 1} and F{sub -1}) and the total variance in the contour, we obtain one feature representing the eccentricity of the object and another denoting its irregularity. Because the number of Fourier terms to be calculated is fixed and small, the algorithm runs in linear time, rather than the O(n log n) time of an FFT. Constraints on object size allow further optimizations so that the total cost of producing the required contour descriptors is about 4n addition/subtraction operations, where n is the length of the contour.
Date: July 16, 2006
Creator: Aragon, Cecilia R. & Aragon, David Bradburn
System: The UNT Digital Library
Development of ITER 15 MA ELMy H-mode Inductive Scenario (open access)

Development of ITER 15 MA ELMy H-mode Inductive Scenario

The poloidal field (PF) coil system on ITER, which provides both feedforward and feedback control of plasma position, shape, and current, is a critical element for achieving mission performance. Analysis of PF capabilities has focused on the 15 MA Q = 10 scenario with a 300-500 s flattop burn phase. The operating space available for the 15 MA ELMy H-mode plasma discharges in ITER and upgrades to the PF coils or associated systems to establish confidence that ITER mission objectives can be reached have been identified. Time dependent self-consistent free-boundary calculations were performed to examine the impact of plasma variability, discharge programming, and plasma disturbances. Based on these calculations a new reference scenario was developed based upon a large bore initial plasma, early divertor transition, low level heating in L-mode, and a late H-mode onset. Equilibrium analyses for this scenario indicate that the original PF coil limitations do not allow low li (<0.8) operation or lower flux states, and the flattop burn durations were predicted to be less than the desired 400 s. This finding motivates the expansion of the operating space, considering several upgrade options to the PF coils. Analysis was also carried out to examine the feedback current …
Date: October 16, 2008
Creator: Kessel, C. E.; Campbell, D.; Gribov, Y.; Saibene, G.; Ambrosino, G.; Casper, T. et al.
System: The UNT Digital Library
An Analysis of the DER Adoption Climate in Japan UsingOptimization Results for Prototype Buildings with U.S. Comparisons (open access)

An Analysis of the DER Adoption Climate in Japan UsingOptimization Results for Prototype Buildings with U.S. Comparisons

This research demonstrates economically optimal distributedenergy resource (DER) system choice using the DER choice and operationsoptimization program, the Distributed Energy Resources Customer AdoptionModel (DER-CAM). DER-CAM finds the optimal combination of installedequipment given prevailing utility tariffs and fuel prices, siteelectrical and thermal loads (including absorption cooling), and a menuof available equipment. It provides a global optimization, albeitidealized, that shows how site useful energy loads can be served atminimum cost. Five prototype Japanese commercial buildings are examinedand DER-CAM is applied to select the economically optimal DER system foreach. Based on the optimization results, energy and emission reductionsare evaluated. Significant decreases in fuel consumption, carbonemissions, and energy costs were seen in the DER-CAM results. Savingswere most noticeable in the prototype sports facility, followed by thehospital, hotel, and office building. Results show that DER with combinedheat and power equipment is a promising efficiency and carbon mitigationstrategy, but that precise system design is necessary. Furthermore, aJapan-U.S. comparison study of policy, technology, and utility tariffsrelevant to DER installation is presented.
Date: June 16, 2006
Creator: Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun & Nishida,Masaru
System: The UNT Digital Library
MULTISCALE MODELING OF POLYMER NANOCOMPOSITES (open access)

MULTISCALE MODELING OF POLYMER NANOCOMPOSITES

Polymer Nanocomposites are an important class of nanomaterials with potential applications including but not limited to structural and cushion materials, electromagnetic and heat shields, conducting plastics, sensors, and catalysts for various chemical and bio processes. Success in most such applications hinges on molecular-level control of structure and assembly, and a deep understanding of how the overall morphology of various components and the interfaces between them affect the composite properties at the macroscale. The length and time-scales associated with such assemblies are prohibitively large for a full atomistic modeling. Instead we adopt a multiscale methodology in which atomic-level interactions between different components of a composite are incorporated into a coarse-grained simulation of the mesoscale morphology, which is then represented on a numerical grid and the macroscopic properties computed using a finite-elements method.
Date: July 16, 2007
Creator: Maiti, A
System: The UNT Digital Library
Dynamics of Adipocyte Turnover in Humans (open access)

Dynamics of Adipocyte Turnover in Humans

Obesity is increasing in an epidemic fashion in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells is thought to be most important. We show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fat cells stays constant in adulthood in lean and obese and even under extreme conditions, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analyzing the integration of {sup 14}C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in obesity, suggesting a tight regulation of fat cell number that is independent of metabolic profile …
Date: July 16, 2007
Creator: Spalding, K; Arner, E; Westermark, P; Bernard, S; Buchholz, B; Bergmann, O et al.
System: The UNT Digital Library
Relative Biological Effectiveness of HZE Fe Ions for Induction of Micro-Nuclei at Low Doses (open access)

Relative Biological Effectiveness of HZE Fe Ions for Induction of Micro-Nuclei at Low Doses

Dose-response curves for induction of micro-nuclei (MN) was measured in Chinese hamster V79 and xrs6 (Ku80-) cells and in human mammary epithelial MCF10A cells in the dose range of 0.05-1 Gy. The Chinese Hamster cells were exposed to 1 GeV/u Fe ions, 600 MeV/u Fe ions, and 300 MeV/u Fe ions (LETs of 151, 176 and 235 keV/{micro}m respectively) as well as with 320 kVp X-rays as reference. Second-order polynomials were fitted to the induction curves and the initial slopes (the alpha values) were used to calculate RBE. For the repair proficient V79 cells the RBE at these low doses increased with LET. The values obtained were 3.1 (LET=151 keV/{micro}m), 4.3 (LET = 176 keV/{micro}m) and 5.7 (LET = 235 keV/{micro}m), while the RBE was close to 1 for the repair deficient xrs6 cells regardless of LET. For the MCF10A cells the RBE was determined for 1 GeV/u Fe ions and found to be 5.4, slightly higher than for V79 cells. To test the effect of shielding, the 1 GeV/u Fe ion beam was intercepted by various thickness of high-density polyethylene plastic absorbers, which resulted in energy loss and fragmentation. It was found that the MN yield for V79 cells …
Date: January 16, 2007
Creator: Groesser, Torsten; Chun, Eugene & Rydberg, Bjorn
System: The UNT Digital Library
Furnace Blower Electricity: National and Regional Savings Potential (open access)

Furnace Blower Electricity: National and Regional Savings Potential

Currently, total electricity consumption of furnaces is unregulated, tested at laboratory conditions using the DOE test procedure, and is reported in the GAMA directory as varying from 76 kWh/year to 1,953 kWh/year. Furnace blowers account for about 80percent of the total furnace electricity consumption and are primarily used to distribute warm air throughout the home during furnace operation as well as distribute cold air during air conditioning operation. Yet the furnace test procedure does not provide a means to calculate the electricity consumption during cooling operation or standby, which account for a large fraction of the total electricity consumption. Furthermore, blower electricity consumption is strongly affected by static pressure. Field data shows that static pressure in the house distribution ducts varies widely and that the static pressure used in the test procedure as well as the calculated fan power is not representative of actual field installations. Therefore, accurate determination of the blower electricity consumption is important to address electricity consumption of furnaces and air conditioners. This paper compares the potential regional and national energy savings of two-stage brushless permanent magnet (BPM) blower motors (the blower design option with the most potential savings that is currently available in the market) to …
Date: May 16, 2008
Creator: Center, Florida Solar Energy; Franco, Victor; Franco, Victor; Lutz, Jim; Lekov, Alex & Gu, Lixing
System: The UNT Digital Library
Estimates of Optimal Backward Perturbations for Linear LeastSquares Problems (open access)

Estimates of Optimal Backward Perturbations for Linear LeastSquares Problems

Numerical tests are used to validate a practical estimatefor the optimal backward errors of linear least squares problems. Thissolves a thirty-year-old problem suggested by Stewart andWilkinson.
Date: July 16, 2007
Creator: Grcar, Joseph F.; Saunders, M.A. & Su, Zheng
System: The UNT Digital Library
HOM and LOM Coupler Optimizations for the ILC Crab Cavity (open access)

HOM and LOM Coupler Optimizations for the ILC Crab Cavity

None
Date: July 16, 2007
Creator: Xiao, L.; Ko, K.; Li, Z.; Ng, C.; Schussman, G.; Seryi, A. et al.
System: The UNT Digital Library
On the non-invariance of space and time scale ranges under Lorentztransformation, and its implications for the study of relativisticinteractions (open access)

On the non-invariance of space and time scale ranges under Lorentztransformation, and its implications for the study of relativisticinteractions

We present an analysis which shows that the ranges of space and time scales spanned by a system are not invariant under the Lorentz transformation. This implies the existence of a frame of reference which minimizes an aggregate measure of the range of space and time scales. Such a frame is derived for example cases: free electron laser, laser-plasma accelerator, and particle beam interacting with electron clouds. Implications for experimental, theoretical and numerical studies are discussed. The most immediate relevance is the reduction by orders of magnitude in computer simulation run times for such systems.
Date: January 16, 2007
Creator: Vay, J. L.
System: The UNT Digital Library
Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes (open access)

Effect of Titanium Substitution on the Compatiblity of Electrodeswith Pyrrolidinium-Based Ionic Liquid Electrolytes

The quest for the development of rechargeable lithium-metal batteries has attracted vigorous worldwide research efforts because this system offers the highest theoretical specific energy [1]. For this to be achieved, the repetitive deposition and stripping of lithium must be close to fully reversible. Thus, alternative electrolytes have been investigated, such as the room-temperature ionic liquid (RTILs). Lithium can be cycled with a high degree of reversibility with efficiencies exceeding 99% using systems based on N-methyl N-alkyl pyrrolidinium (P{sub 1X}{sup +}) combined with the TFSI anion [2]. More recent efforts have been directed towards systems based on P{sub 1X}{sup +} cations with the FSI anion and appear to be even more promising [3,4]. In this work, we discuss to what extent RTILs based on P{sub 1X}{sup +} cations with TFSI or FSI anions can be used as electrolytes for rechargeable Li batteries. In particular, their physical and chemical properties are thoroughly discussed so as to explain the difference observed in their electrochemical behavior. Although these two systems seem to be stable against lithium, their compatibilities with cathode materials require full assessment as well. Thus, various manganese oxide cathodes are investigated in this study. Strategies to minimize cathode dissolution are also debated, …
Date: May 16, 2007
Creator: Saint, Juliette A.; Shin, Joon-Ho; Best, Adam; Hollenkamp,Anthony; Kerr, John & Doeff, Marca M.
System: The UNT Digital Library
The Assembly of Galaxy Clusters (open access)

The Assembly of Galaxy Clusters

We study the formation of fifty-three galaxy cluster-size dark matter halos (M = 10{sup 14.0-14.76} M{sub {circle_dot}}) formed within a pair of cosmological {Lambda}CDM N-body simulations, and track the accretion histories of cluster subhalos with masses large enough to host {approx} 0.1L{sub *} galaxies. By associating subhalos with cluster galaxies, we find the majority of galaxies in clusters experience no 'pre-processing' in the group environment prior to their accretion into the cluster. On average, {approx} 70% of cluster galaxies fall into the cluster potential directly from the field, with no luminous companions in their host halos at the time of accretion; and less than {approx} 12% are accreted as members of groups with five or more galaxies. Moreover, we find that cluster galaxies are significantly less likely to have experienced a merger in the recent past ({approx}< 6 Gyr) than a field halo of the same mass. These results suggest that local, cluster processes like ram-pressure stripping, galaxy harassment, or strangulation play the dominant role in explaining the difference between cluster and field populations at a fixed stellar mass; and that pre-evolution or past merging in the group environment is of secondary importance for setting cluster galaxy properties for most …
Date: May 16, 2008
Creator: Berrier, Joel C.; Stewart, Kyle R.; Bullock, James S.; Purcell, Chris W.; Barton, Elizabeth J. & Wechsler, Risa H.
System: The UNT Digital Library
ARPES study of the evolution of band structure and charge density wave properties in RTe3 ( R=Y , La, Ce, Sm, Gd, Tb, and Dy) (open access)

ARPES study of the evolution of band structure and charge density wave properties in RTe3 ( R=Y , La, Ce, Sm, Gd, Tb, and Dy)

We present a detailed angle-resolved photoemission spectroscopy (ARPES) investigation of the RTe3 family, which sets this system as an ideal"textbook" example for the formation of a nesting driven charge density wave (CDW). This family indeed exhibits the full range of phenomena that can be associated to CDWinstabilities, from the opening of large gaps on the best nested parts of Fermi surface (up to 0.4 eV), to the existence of residual metallic pockets. ARPES is the best suited technique to characterize these features, thanks to its unique ability to resolve the electronic structure in k space. An additional advantage of RTe3 is that theband structure can be very accurately described by a simple two dimensional tight-binding (TB) model, which allows one to understand and easily reproduce many characteristics of the CDW. In this paper, we first establish the main features of the electronic structure by comparing our ARPES measurements with the linear muffin-tinorbital band calculations. We use this to define the validity and limits of the TB model. We then present a complete description of the CDW properties and of their strong evolution as a function of R. Using simple models, we are able to reproduce perfectly the evolution of gaps …
Date: January 16, 2008
Creator: Hussain, Zahid; Brouet, Veronique; Yang, Wanli; Zhou, Xingjiang; Hussain, Zahid; Moore, R. G. et al.
System: The UNT Digital Library
Giant Dipole Resonance in the hot and thermalized 132Ce nucleus: damping of collective modes at finite temperature (open access)

Giant Dipole Resonance in the hot and thermalized 132Ce nucleus: damping of collective modes at finite temperature

The {gamma} decay of the Giant Dipole Resonance in the {sup 132}Ce compound nucleus with temperature up to {approx} 4 MeV has been measured. The symmetric {sup 64}Ni + {sup 68}Zn at E{sub beam} = 300, 400, 500 MeV and the asymmetric reaction {sup 16}O + {sup 116}Sn at E{sub beam} = 130, 250 MeV have been investigated. Light charged particles and {gamma} rays have been detected in coincidence with the recoiling compound system. In the case of the mass symmetric {sup 64}Ni induced reaction the {gamma} and charged particle spectral shapes are found to be consistent with the emission from a fully equilibrated compound nuclei and the GDR parameters are extracted from the data using a statistical model analysis. The GDR width is found to increase almost linear with temperature. This increase is rather well reproduced within a model which includes both the thermal fluctuation of the nuclear shape and the lifetime of the compound nucleus.
Date: June 16, 2006
Creator: Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Brambilla, S. et al.
System: The UNT Digital Library
Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation (open access)

Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation

The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-based method with 3D open boundary conditions and longitudinal periodic boundary conditions. This code was completely rewritten in the late 1990s based on a message passing parallel programming paradigm using Fortran 90 and MPI following an object-oriented software design. This improved the code's scalability on large parallel computer systems and also gave the code better software maintainability and extensibility [2]. In the following years, under the SciDAC-1 accelerator project, the code was extended to include more accelerating and focusing elements such as DTL, CCL, superconducting linac, solenoid, dipole, multipoles, and others. Besides the original split-operator based integrator, a direct integration of Lorentz equations of motion using a leap-frog algorithm was also added to the IMPACT code to handle arbitrary external nonlinear fields. This integrator can read in 3D electromagnetic …
Date: November 16, 2006
Creator: Qiang, J. & Ryne, R.D.
System: The UNT Digital Library
Lepton Flavour Violation And Baryon Number Non-Conservation in tau to Lambda + h (open access)

Lepton Flavour Violation And Baryon Number Non-Conservation in tau to Lambda + h

We have searched for the violation of baryon number B and lepton number L in the (B - L)-conserving modes {tau}{sup -} {yields} {bar {Lambda}}{pi}{sup -} and {tau}{sup -} {yields} {bar {Lambda}}K{sup -} as well as the (B - L)-violating modes {tau}{sup -} {yields} {Lambda}{pi}{sup -} and {tau}{sup -} {yields} {Lambda}K{sup -} using 237 fb{sup -1} of data collected with the BaBar detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings. We do not observe any signal and we determine preliminary upper limits on the branching fractions {Beta}({tau}{sup -} {yields} {bar {Lambda}}{pi}{sup -}) < 5.9 x 10{sup -8}, {Beta}({tau}{sup -}{yields} {Lambda}{pi}{sup -}) < 5.8 x 10{sup -6}, {Beta}({tau}{sup -} {yields} {bar {Lambda}}K{sup -}) < 7.2 x 10{sup -8}, and {Beta}({tau}{sup -} {yields} {Lambda}K{sup -}) < 15 x 10{sup -8} at 90% confidence level.
Date: November 16, 2007
Creator: Lafferty, G.D.
System: The UNT Digital Library
Toroidally Asymmetric Distributions of Hydrocarbon (CD) Emission and Chemical Sputtering Sources in DIII-D (open access)

Toroidally Asymmetric Distributions of Hydrocarbon (CD) Emission and Chemical Sputtering Sources in DIII-D

Measurements in DIII-D show that the carbon chemical sputtering sources along the inner divertor and center post are toroidally periodic and highest at the upstream tile edge. Imaging with a tangentially viewing camera and visible spectroscopy were used to monitor the emission from molecular hydrocarbons (CH/CD) at 430.8 nm and deuterium neutrals in attached and partially detached divertors of low-confinement mode plasmas. In contrast to the toroidally periodic CD distribution, emission from deuterium neutrals was observed to be toroidally symmetric along the inner strike zone. The toroidal distribution of the measured tile surface temperature in the inner divertor correlates with that of the CD emission, suggesting larger parallel particle and heat fluxes to the upstream tile edge, either due to toroidal tile gaps or height steps between adjacent tiles.
Date: May 16, 2006
Creator: Groth, M.; Brooks, N. H.; Fenstermacher, M. E.; Lasnier, C. J.; McLean, A. G. & Watkins, J. G.
System: The UNT Digital Library
Kaolinite dissolution and precipitation kinetics at 22oC and pH4 (open access)

Kaolinite dissolution and precipitation kinetics at 22oC and pH4

Dissolution and precipitation rates of low defect Georgia kaolinite (KGa-1b) as a function of Gibbs free energy of reaction (or reaction affinity) were measured at 22 C and pH 4 in continuously stirred flow through reactors. Steady state dissolution experiments showed slightly incongruent dissolution, with a Si/Al ratio of about 1.12 that is attributed to the re-adsorption of Al on to the kaolinite surface. No inhibition of the kaolinite dissolution rate was apparent when dissolved aluminum was varied from 0 and 60 {micro}M. The relationship between dissolution rates and the reaction affinity can be described well by a Transition State Theory (TST) rate formulation with a Temkin coefficient of 2 R{sub diss} (mol/m{sup 2}s) = 1.15 x 10{sup -13} [1-exp(-{Delta}G/2RT)]. Stopping of flow in a close to equilibrium dissolution experiment yielded at solubility constant for kaolinite at 22 C of 10{sup 7.57}. Experiments on the precipitation kinetics of kaolinite showed a more complex behavior. One conducted using kaolinite seed that had previously undergone extensive dissolution under far from equilibrium conditions for 5 months showed a quasi-steady state precipitation rate for 105 hours that was compatible with the TST expression above. After this initial period, however, precipitation rates decreased by an …
Date: July 16, 2007
Creator: Yang, Li & Steefel, Carl I.
System: The UNT Digital Library
Development Status of the ILC Marx Modulator (open access)

Development Status of the ILC Marx Modulator

The ILC Marx Modulator is under development as a lower cost alternative to the 'Baseline Conceptual Design' (BCD) klystron modulator. Construction of a prototype Marx is complete and testing is underway at SLAC. The Marx employs solid state elements, IGBTs and diodes, to control the charge, discharge and isolation of the modules. The prototype is based on a stack of sixteen modules, each initially charged to {approx}11 kV, which are arranged in a Marx topology. Initially, eleven modules combine to produce the 120 kV output pulse. The remaining modules are switched in after appropriate delays to compensate for the voltage droop that results from the discharge of the energy storage capacitors. Additional elements will further regulate the output voltage to {+-} 0.5%. The Marx presents several advantages over the conventional klystron modulator designs. It is physically smaller; there is no pulse transformer (quite massive at these parameters) and the energy storage capacitor bank is quite small, owing to the active droop compensation. It is oil-free; voltage hold-off is achieved using air insulation. It is air cooled; the secondary air-water heat exchanger is physically isolated from the electronic components. This paper outlines the current developmental status of the prototype Marx. It …
Date: June 16, 2008
Creator: Nguyen, M.; Beukers, T.; Burkhart, C.; Larsen, R.; Olsen, J. & Tang, T.
System: The UNT Digital Library
Commissioning Results of the LCLS Injector (open access)

Commissioning Results of the LCLS Injector

The Linac Coherent Light Source (LCLS) is a SASE xray Free-Electron Laser (FEL) project presently under construction at SLAC. The injector section, from drive-laser and RF photocathode gun through first bunch compressor chicane, was installed in fall 2006. Initial system commissioning with an electron beam has recently been completed. The second phase of construction, including second bunch compressor and full linac, is planned for 2008. In this paper, we report experimental results and experience gained during the first phase of machine commissioning. This includes the cathode, drive laser, RF photocathode gun, linac booster section, S-band and X-band RF systems, first bunch compressor, and the various beam diagnostics.
Date: November 16, 2007
Creator: Dowell, D. H.; Akre, R.; Ding, Y.; Emma, P.; Frisch, J.; Gilevich, S. et al.
System: The UNT Digital Library
Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough. (open access)

Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough.

Desulfovibrio vulgaris Hildenborough belongs to a class ofsulfate-reducing bacteria (SRB) and is found ubiquitously in nature.Given the importance of SRB-mediated reduction for bioremediation ofmetal ion contaminants, ongoing research on D. vulgaris has been in thedirection of elucidating regulatory mechanisms for this organism under avariety of stress conditions. This work presents a global view of thisorganism's response to elevated growth temperature using whole-celltranscriptomics and proteomics tools. Transcriptional response (1.7-foldchange or greater; Z>1.5) ranged from 1,135 genes at 15 min to 1,463genes at 120 min for a temperature up-shift of 13oC from a growthtemperature of 37oC for this organism and suggested both direct andindirect modes of heat sensing. Clusters of orthologous group categoriesthat were significantly affected included posttranslationalmodifications; protein turnover and chaperones (up-regulated); energyproduction and conversion (down-regulated), nucleotide transport,metabolism (down-regulated), and translation; ribosomal structure; andbiogenesis (down-regulated). Analysis of the genome sequence revealed thepresence of features of both negative and positive regulation whichincluded the CIRCE element and promoter sequences corresponding to thealternate sigma factors ?32 and ?54. While mechanisms of heat shockcontrol for some genes appeared to coincide with those established forEscherichia coli and Bacillus subtilis, the presence of unique controlschemes for several other genes was also evident. Analysis of proteinexpression levels using …
Date: September 16, 2005
Creator: Chhabra, S. R.; He, Q.; Huang, K. H.; Gaucher, S. P.; Alm, E. J.; He, Z. et al.
System: The UNT Digital Library
ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS (open access)

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS

Comprehensive test ban monitoring in terms of location and discrimination has progressed significantly in recent years. However, the characterization of sources and the estimation of low yields remains a particular challenge. As the recent Korean shot demonstrated, we can probably expect to have a small set of teleseismic, far-regional and high-frequency regional data to analyze in estimating the yield of an event. Since stacking helps to bring signals out of the noise, it becomes useful to conduct comparable analyses on neighboring events, earthquakes in this case. If these auxiliary events have accurate moments and source descriptions, we have a means of directly comparing effective source strengths. Although we will rely on modeling codes, 1D, 2D, and 3D, we will also apply a broadband calibration procedure to use longer periods (P>5s) waveform data to calibrate short-period (P between .5 to 2 Hz) and high-frequency (P between 2 to 10 Hz) as path specify station corrections from well-known regional sources. We have expanded our basic Cut-and-Paste (CAP) methodology to include not only timing shifts but also amplitude (f) corrections at recording sites. The name of this method was derived from source inversions that allow timing shifts between 'waveform segments' (or cutting the …
Date: July 16, 2007
Creator: Helmberger, D; Tromp, J & Rodgers, A
System: The UNT Digital Library
LOCALIZED CORROSION OF A537 STEEL IN SIMULATED WASTE TANK SOLUTION (open access)

LOCALIZED CORROSION OF A537 STEEL IN SIMULATED WASTE TANK SOLUTION

None
Date: October 16, 2008
Creator: Hoffman, E
System: The UNT Digital Library
Autocatalytic water dissociation on Cu(110) at near ambient conditions (open access)

Autocatalytic water dissociation on Cu(110) at near ambient conditions

Autocatalytic dissociation of water on the Cu(110) metal surface is demonstrated based on X-ray photoelectron spectroscopy studies carried out in-situ under near ambient conditions of water vapor pressure (1 Torr) and temperature (275-520 K). The autocatalytic reaction is explained as the result of the strong hydrogen-bond in the H{sub 2}O-OH complex of the dissociated final state, which lowers the water dissociation barrier according to the Broensted-Evans-Polanyi relations. A simple chemical bonding picture is presented which predicts autocatalytic water dissociation to be a general phenomenon on metal surfaces.
Date: May 16, 2007
Creator: Mulleregan, Alice; Andersson, Klas; Ketteler, Guido; Bluhm, Hendrik; Yamamoto, Susumu; Ogasawara, Hirohito et al.
System: The UNT Digital Library