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2012 CHEMISTRY & PHYSICS OF GRAPHITIC CARBON MATERIALS GORDON RESEARCH CONFERENCE, JUNE 17-22, 2012 (open access)

2012 CHEMISTRY & PHYSICS OF GRAPHITIC CARBON MATERIALS GORDON RESEARCH CONFERENCE, JUNE 17-22, 2012

This conference will highlight the urgency for research on graphitic carbon materials and gather scientists in physics, chemistry, and engineering to tackle the challenges in this field. The conference will focus on scalable synthesis, characterization, novel physical and electronic properties, structure-properties relationship studies, and new applications of the carbon materials. Contributors
Date: June 22, 2012
Creator: Fertig, Herbert
Object Type: Article
System: The UNT Digital Library
Defining How a Microbial Cell Senses and Responds to a Redox Active Environment (open access)

Defining How a Microbial Cell Senses and Responds to a Redox Active Environment

This grant was for four years, and the work was designed to look at the mechanisms of extracellular electron transfer by the dissimilatory iron reducing bacteria Shewanella oneidensis MR-1, and other closely related Shewanella strains and species. During this work, we defined many of the basic physiological and biochemical properties of the Shewanella group, Much of which was summarized in review articles. We also finished and published the genome sequence of strain MR-1, the first of the shewanellae to have its genome sequenced. Control at the transcriptional and translational level was studied in collaboration with colleagues at PNNL and ANL. We utilized synchrotron X-ray radiation to image both the bacteria and the metal oxide particles via a technique called STXM, synchrotron X-ray absorption (ref. No.9), and X-ray microbeam analysis. We purified several of the cytochromes involved with metal reduction, and improved gene annotation of the MR-1 genome. The conductive appendages (nanowires) of MR-1 were described and characterized. Comparative genomics and biochemistry revealed that the pathway for the utilization of N-acetyl glucosamine in the various strains of Shewanella exhibited great variability, and had a number of previously unknown genes.
Date: June 22, 2012
Creator: Nealson, Kenneth H.
Object Type: Report
System: The UNT Digital Library
High-speed, multi-channel detector readout electronics for fast radiation detectors (open access)

High-speed, multi-channel detector readout electronics for fast radiation detectors

In this project, we are developing a high speed digital spectrometer that a) captures detector waveforms at rates up to 500 MSPS b) has upgraded event data acquisition with additional data buffers for zero dead time operation c) moves energy calculations to the FPGA to increase spectrometer throughput in fast scintillator applications d) uses a streamlined architecture and high speed data interface for even faster readout to the host PC These features are in addition to the standard functions in our existing spectrometers such as digitization, programmable trigger and energy filters, pileup inspection, data acquisition with energy and time stamps, MCA histograms, and run statistics. In Phase I, we upgraded one of our existing spectrometer designs to demonstrate the key principle of fast waveform capture using a 500 MSPS, 12 bit ADC and a Xilinx Virtex-4 FPGA. This upgraded spectrometer, named P500, performed well in initial tests of energy resolution, pulse shape analysis, and timing measurements, thus achieving item (a) above. In Phase II, we are revising the P500 to build a commercial prototype with the improvements listed in items (b)-(d). As described in the previous report, two devices were built to pursue this goal, named the Pixie-500 and the …
Date: June 22, 2012
Creator: Hennig, Wolfgang
Object Type: Report
System: The UNT Digital Library
LSST Charge-Coupled Device Calibration (open access)

LSST Charge-Coupled Device Calibration

The prototype charge-coupled device created at the Stanford Linear Accelerator Center for the Large Synoptic Survey Telescope must be tested to check its functionality and performance. It was installed into the Calypso telescope in Arizona in November of 2008 for this purpose. Since then it has taken many images of various astronomical objects. By doing photometry on standard stars in these images, we can compare our magnitude results to the known magnitudes of these stars. This comparison allows us to then determine the chip's performance and functional capabilities. Expecting to see first light in 2016, the Large Synoptic Survey Telescope (LSST) is an extremely large ground based telescope that anticipates funding and will be built in Chile. Described as 'Wide-Fast-Deep', the LSST will have an unprecedented wide field of view (ten square degrees for surveys), short exposures (fifteen to thirty seconds and still see faint objects), and the largest digital camera in the world. One of the goals hoped to be achieved with this camera is the measurement of dark matter using strong and weak gravitational lensing. Gravitational lensing occurs when a large cluster of galaxies distorts the light from a galaxy behind this cluster. This causes an arc of …
Date: June 22, 2011
Creator: Stout, Tiarra Johannas & /SLAC, /Idaho State U.
Object Type: Report
System: The UNT Digital Library
Analysis of Femtosecond Timing Noise and Stability in Microwave Components (open access)

Analysis of Femtosecond Timing Noise and Stability in Microwave Components

To probe chemical dynamics, X-ray pump-probe experiments trigger a change in a sample with an optical laser pulse, followed by an X-ray probe. At the Linac Coherent Light Source, LCLS, timing differences between the optical pulse and x-ray probe have been observed with an accuracy as low as 50 femtoseconds. This sets a lower bound on the number of frames one can arrange over a time scale to recreate a 'movie' of the chemical reaction. The timing system is based on phase measurements from signals corresponding to the two laser pulses; these measurements are done by using a double-balanced mixer for detection. To increase the accuracy of the system, this paper studies parameters affecting phase detection systems based on mixers, such as signal input power, noise levels, temperature drift, and the effect these parameters have on components such as the mixers, splitters, amplifiers, and phase shifters. Noise data taken with a spectrum analyzer show that splitters based on ferrite cores perform with less noise than strip-line splitters. The data also shows that noise in specific mixers does not correspond with the changes in sensitivity per input power level. Temperature drift is seen to exist on a scale between 1 and …
Date: June 22, 2011
Creator: Whalen, Michael R. & /SLAC, /Stevens Tech.
Object Type: Report
System: The UNT Digital Library
Effectiveness of alumina armor plate against high velocity projectiles (open access)

Effectiveness of alumina armor plate against high velocity projectiles

The thickness of alumina armor plate is determined which will stop a 10-g steel projectile traveling at 2.1 and 3.0 mm/s.
Date: June 22, 1976
Creator: Hord, B. L.
Object Type: Report
System: The UNT Digital Library
Provisional Process Specifications for the Attachment of Support Rails by Electrical Resistance Spot Welding (open access)

Provisional Process Specifications for the Attachment of Support Rails by Electrical Resistance Spot Welding

This report presents provisional specifications for the modifications and additions to the Lead Dip Canning Process for Heat Treated Uranium for the production test fabrication of projection fuel elements by resistance spot welding.
Date: June 22, 1960
Creator: Padgett, E. V.
Object Type: Report
System: The UNT Digital Library
190-C pump capacity (open access)

190-C pump capacity

The purpose of this document is to update 190-C pump capacity information previous released in HW-52449{sup 1} and HW-58580{sup 2}. Improvements in motor cooling has resulted in raising the previous 3500 HP limit to 3660 HP{sup 3} thus increasing total pumping capacity.
Date: June 22, 1959
Creator: Watson, D. F.
Object Type: Report
System: The UNT Digital Library
Final report for Allied-Signal Aerospace Company, Kansas City Division on protective glove permeation analysis (open access)

Final report for Allied-Signal Aerospace Company, Kansas City Division on protective glove permeation analysis

We conducted 25 separate glove fabric permeation studies during this project. The permeations were carried out in the small (1 inch) glass ASTM cell. One other permeation study was carded out with a large (two inch) modified ASTM cell for comparison with the small cell results. We also compared the LLNL procedure from both large and small cells with the standard ASTM test procedure which uses a liquid solution on the breakthrough side of the fabric (the liquid is then sampled on a periodic basis). In all comparisons we observed a close-correlation in breakthrough times between the two procedures and the two cell sizes. In the course of this study, we tested ten different glove materials. These included neoprene (original ASTM round-robin sheet stock, 16 mil thickness), Edmont Sol-Vex (nitrile), Pioneer nitrile, Pioneer Pylox (polyvinyl chloride), North Viton (trademark for fluoroelastomers), North SilverShield (Norfoil, trademark for a flexible metallized laminate), Safety 4 4H (patented plastic laminate), and QRP PolyTuff (polyurethane) 20G-2000 (5 mil), 23G-2300 (1.5 mil), and 25G-2500 (1.5 mil). Three of the glove materials, Viton and Silver Shield (North), and 4H (Safety 4), did not allow any permeation measurable by our system to either 1,2-dichloroethane or 3% diphenylmercury (in …
Date: June 22, 1990
Creator: Swearengen, P. M.; Johnson, J. S. & Priante, S. J.
Object Type: Report
System: The UNT Digital Library
Proposed solid state diffusion bonding (SSDB) process: Gas pressure bonding (open access)

Proposed solid state diffusion bonding (SSDB) process: Gas pressure bonding

This report presents a technical and economic study of the lead-dip canning process compared to two types of solid state diffusion bonding processes (hot-press die and gas pressure bonding) for Hanford production fuel elements (exclusive of NPR). It is concluded that either bonding process has potential advantages over the lead-dip process. The gas pressure bonding process has advantages over the hot-press die process.
Date: June 22, 1960
Creator: Weakley, E. A.
Object Type: Report
System: The UNT Digital Library
Natural gas monthly, June 1993 (open access)

Natural gas monthly, June 1993

The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information.
Date: June 22, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
100 Area D4 Project Semi-Annual 2006 Building Completion Report, August 2005 - April 2006 (open access)

100 Area D4 Project Semi-Annual 2006 Building Completion Report, August 2005 - April 2006

This report documents the decontamination, decommissioining (D&D) and the demolition of select facilities in the 100 Area of the Hanford Site as required by DOE G 430.1-4.
Date: June 22, 2006
Creator: Griff, B. C.
Object Type: Report
System: The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition (open access)

Development of a Novel Catalyst for NO Decomposition

Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date: June 22, 2007
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type: Report
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

The work under this grant consisted of encouraging community activities for the development of parallel programming patterns. This work was in conjunction with the research performed under the Pmodels award - where research was pursued on the development for new parallel programming models. Work on programming patterns does not have, as a goal, the invention of new technology. Rather, it is about codifying existing practice, so as to provide practitioners with a common language. This facilitates education and communication between practitioners. In addition, it helps in the design of new parallel frameworks and languages. One major issue in their design is expressiveness: To what extent does the language or framework facilitates the expression of common programming patterns. In order to assess expressiveness in any useful way, it is necessary to identify those common patterns.
Date: June 22, 2009
Creator: Snir, Marc
Object Type: Report
System: The UNT Digital Library
Optimal tuning and calibration of bendable mirrors with slope measuring profilers (open access)

Optimal tuning and calibration of bendable mirrors with slope measuring profilers

We describe a technique to optimally tune and calibrate bendable x-ray optics for sub-micron focusing. The focusing is divided between two elliptically cylindrical reflecting elements, a Kirkpatrick-Baez (KB) pair. Each optic is shaped by applying unequal bending couples to each end of a flat mirror. The developed technique allowsoptimal tuning of these systems using surface slope data obtained with a slope measuring instrument, the long trace profiler (LTP). Due to the near linearity of the problem, the minimal set of data necessary for the tuning of each bender, consists of only three slope traces measured before and after a single adjustment of each bending couple. The data are analyzed with software realizing a method of regression analysis with experimentally found characteristic functions of the benders. The resulting approximation to the functional dependence of the desired shape provides nearly final settings. Moreover, the characteristic functions of the benders found in the course of tuning, can be used for retuning to a new desired shape without removal from the beamline and re-measuring. We perform a ray trace, using profiler data for the finally tuned optics, predicting the performance to be expected during use of the optics on the beamline.
Date: June 22, 2009
Creator: McKinney, Wayne; Kirschman, Jonathan; MacDowell, Alastair; Warwick, Tony & Yashchuk, Valeriy
Object Type: Article
System: The UNT Digital Library
METHOD TO PREVENT SULFUR ACCUMULATION INSIDE MEMBRANE ELECTRODE ASSEMBLY (open access)

METHOD TO PREVENT SULFUR ACCUMULATION INSIDE MEMBRANE ELECTRODE ASSEMBLY

HyS is conceptually the simplest of the thermochemical cycles and involves only sulfur chemistry. In the HyS Cycle hydrogen gas (H{sub 2}) is produced at the cathode of the electrochemical cell (or electrolyzer). Sulfur dioxide (SO{sub 2}) is oxidized at the anode to form sulfuric acid (H{sub 2}SO{sub 4}) and protons (H{sup +}) as illustrated below. A separate high temperature reaction decomposes the sulfuric acid to water and sulfur dioxide which are recycled to the electrolyzers, and oxygen which is separated out as a secondary product. The electrolyzer includes a membrane that will allow hydrogen ions to pass through but block the flow of hydrogen gas. The membrane is also intended to prevent other chemical species from migrating between electrodes and undergoing undesired reactions that could poison the cathode or reduce overall process efficiency. In conventional water electrolysis, water is oxidized at the anode to produce protons and oxygen. The standard cell potential for conventional water electrolysis is 1.23 volts at 25 C. However, commercial electrolyzers typically require higher voltages ranging from 1.8 V to 2.6 V [Kirk-Othmer, 1991]. The oxidation of sulfur dioxide instead of water in the HyS electrolyzer occurs at a much lower potential. For example, the …
Date: June 22, 2009
Creator: Steimke, J.; Steeper, T.; Herman, D.; Colon-Mercado, H. & Elvington, M.
Object Type: Report
System: The UNT Digital Library
Data Acquisition in a High Harmonic Generation Lab and at LCLS (open access)

Data Acquisition in a High Harmonic Generation Lab and at LCLS

In this paper, we examine data acquisition in a high harmonic generation (HHG) lab and preliminary data analysis with the Cyclohexadiene Collaboration at the Linac Coherent Lightsource (LCLS) at SLAC National Accelerator Laboratory. HHG experiments have a large number of parameters that need to be monitored constantly. In particular, the pressure of the target is critical to HHG yield. However, this pressure can fluctuate wildly and without a tool to monitor it, it is difficult to analyze the correlation between HHG yield and the pressure. I used the Arduino microcontroller board and created a complementary MATLAB graphical user interface (GUI), thereby enhancing the ease with which users can acquire time-stamped parameter data. Using the Arduino, it is much easier to match the pressure to the corresponding HHG yield. Collecting data by using the Arduino and the GUI is flexible, user-friendly, and cost-effective. In the future, we hope to be able to control and monitor parts of the lab with the Arduino alone. While more parameter information is needed in the HHG lab, we needed to reduce the amount of data during the cyclohexadiene collaboration. This was achieved by sorting the data into bins and filtering out unnecessary details. This method …
Date: June 22, 2011
Creator: Hirokawa, Takako
Object Type: Report
System: The UNT Digital Library
Impedances of Laminated Vacuum Chambers (open access)

Impedances of Laminated Vacuum Chambers

First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].
Date: June 22, 2011
Creator: Burov, A. & Lebedev, V.
Object Type: Report
System: The UNT Digital Library
Improving Phase Measurement Procedures for Pump-Probe Experiments (open access)

Improving Phase Measurement Procedures for Pump-Probe Experiments

Pump-probe experiments use a visible laser to excite an atom or molecule, while an X-ray pulse measures its shape. The phases and pulse times of each beam are used to calculate the object's positing at a given time - a moving picture of the chemical reaction. Currently, the fastest X-ray pulses can travel a time-length of five femtoseconds. However, present-day phase measurements can only be done as quickly as 50 femtoseconds. The purpose of this research is to explore ways in which phase-timing measurements can be improved. Three experiments are undergone to find the key factors in phase-timing. Different frequency mixers, the radio frequency (RF) components used for phase measurement, are tested for the highest sensitivity. These same mixers are then tested using two different power splitters for the lowest noise-to-sensitivity ratio. Lastly, the temperature dependency of phase is explored by testing each component at a range of temperatures to see how the phase is affected. This research demonstrated that certain mixers were more sensitive than others; on average, one mixer performed the best with a sensitivity of 0.0230 V/ps. The results also showed that same mixer combined with one splitter gave the best noise-to-sensitivity ratio overall with an average …
Date: June 22, 2011
Creator: Perkins, Cara P.
Object Type: Report
System: The UNT Digital Library
Investigation into Nanostructured Lanthanum Halides and CeBr{sub 3} for Nuclear Radiation Detection (open access)

Investigation into Nanostructured Lanthanum Halides and CeBr{sub 3} for Nuclear Radiation Detection

This slide-show presents work on radiation detection with nanostructured lanthanum halides and CeBr{sub 3}. The goal is to extend the gamma energy response on both low and high-energy regimes by demonstrating the ability to detect low-energy x-rays and relatively high-energy activation prompt gamma rays simultaneously using the nano-structured lanthanum bromide, lanthanum fluoride, cerium bromide, or other nanocrystal material. Homogeneous and nano structure cases are compared.
Date: June 22, 2011
Creator: Guss, P., Guise, R., Mukhopadhyay, S., Yuan, D.
Object Type: Article
System: The UNT Digital Library
Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope (open access)

Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope

The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope provides charged particle rejection for the Large Area Telescope (LAT). We use two calibrations used by the ACD to conduct three studies on the performance of the ACD. We examine the trending of the calibrations to search for damage and find a timescale over which the calibrations can be considered reliable. We also calculated the number of photoelectrons counted by a PMT on the ACD from a normal proton. Third, we calculated the veto efficiencies of the ACD for two different veto settings. The trends of the calibrations exhibited no signs of damage, and indicated timescales of reliability for the calibrations of one to two years. The number of photoelectrons calculated ranged from 5 to 25. Large errors in the effect of the energy spectrum of the charged particles caused these values to have very large errors of around 60 percent. Finally, the veto efficiencies were found to be very high at both veto values, both for charged particles and for the lower energy backsplash spectrum. The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope is a detector system built around the silicon strip tracker …
Date: June 22, 2011
Creator: Kachulis, Chris
Object Type: Report
System: The UNT Digital Library
Plot/SurfW: Plotting Utility for EDGE2D Output (open access)

Plot/SurfW: Plotting Utility for EDGE2D Output

This report describes a utility that was developed to display EDGE2D results. The utility is focused on results that relate to impurity density, velocity, and particle fluxes in the SOL and divertor. Due to the complicated nature of 2D impurity sources, the concentration of the thermal force near the separatrix and near the divertor entrance, the impurity flow pattern and impurity densities are not necessarily easy to visualize. Thus, we wanted a utility that allowed simple and quick visualization of the impurity behavior. In order to achieve this we overlaid the divertor hardware for plots inside the divertor and we expanded the appearance of the main chamber SOL by plotting distance along the field lines vs. SOL depth with the density (or velocity or flux or other quantity) the false colour. Also, we allowed for the plotted variable to be a function of the other EDGE2D result variables. __________________________________________________
Date: June 22, 2012
Creator: Strachan, W.M. Davis and J.D.
Object Type: Report
System: The UNT Digital Library
X-Band RF Gun Development (open access)

X-Band RF Gun Development

In support of the MEGa-ray program at LLNL and the High Gradient research program at SLAC, a new X-band multi-cell RF gun is being developed. This gun, similar to earlier guns developed at SLAC for Compton X-ray source program, will be a standing wave structure made of 5.5 cells operating in the pi mode with copper cathode. This gun was designed following criteria used to build SLAC X-band high gradient accelerating structures. It is anticipated that this gun will operate with surface electric fields on the cathode of 200 MeV/m with low breakdown rate. RF will be coupled into the structure through a final cell with symmetric duel feeds and with a shape optimized to minimize quadrupole field components. In addition, geometry changes to the original gun, operated with Compton X-ray source, will include a wider RF mode separation, reduced surface electric and magnetic fields.
Date: June 22, 2012
Creator: Vlieks, Arnold; Dolgashev, Valery; Tantawi, Sami; Anderson, Scott; Hartemann, Fred & Marsh, Roark
Object Type: Article
System: The UNT Digital Library
Investigation of novel decay B _____ ____(2S)____K at BaBar (open access)

Investigation of novel decay B _____ ____(2S)____K at BaBar

We investigate the undocumented B meson decay, B{sup +} {yields} {Psi}(2S){omega}K{sup +}. The data were collected with the BaBar detector at the SLAC PEP-II asymmetric-energy e{sup +}e{sup -} collier operating at the {gamma}(4S) resonance, a center-of-mass energy of 10.58 GeV/c{sup 2}. The {gamma}(4S) resonance primarily decays to pairs of B-mesons. The BaBar collaboration at the PEP-II ring was located at the SLAC National Accelerator Laboratory and was designed to study the collisions of positrons and electrons. The e{sup -}e{sup +} pairs collide at asymmetric energies, resulting in a center of mass which is traveling at relativistic speeds. The resulting time dilation allows the decaying particles to travel large distances through the detector before undergoing their rapid decays, a process that occurs in the in the center of mass frame over extremely small distances. As they travel through silicon vertex trackers, a drift chamber, a Cerenkov radiation detector and finally an electromagnetic calorimeter, we measure the charge, energy, momentum, and particle identification in order to reconstruct the decays that have occurred. While all well understood mesons currently fall into the qq model, the quark model has no a priori exclusion of higher configuration states such as qqqq which has led experimentalists …
Date: June 22, 2011
Creator: Schalch, Jacob & /SLAC, /Oberlin Coll.
Object Type: Report
System: The UNT Digital Library