JV Task 126 - Mercury Control Technologies for Electric Utilities Burning Bituminous Coal (open access)

JV Task 126 - Mercury Control Technologies for Electric Utilities Burning Bituminous Coal

The EERC developed an applied research consortium project to test cost-effective mercury (Hg) control technologies for utilities burning bituminous coals. The project goal was to test innovative Hg control technologies that have the potential to reduce Hg emissions from bituminous coal-fired power plants by {ge}90% at costs of one-half to three-quarters of current estimates for activated carbon injection (ACI). Hg control technology evaluations were performed using the EERC's combustion test facility (CTF). The CTF was fired on pulverized bituminous coals at 550,000 Btu/hr (580 MJ/hr). The CTF was configured with the following air pollution control devices (APCDs): selective catalytic reduction (SCR) unit, electrostatic precipitator (ESP), and wet flue gas desulfurization system (WFDS). The Hg control technologies investigated as part of this project included ACI (three Norit Americas, Inc., and eleven Envergex sorbents), elemental mercury (Hg{sup 0}) oxidation catalysts (i.e., the noble metals in Hitachi Zosen, Cormetech, and Hitachi SCR catalysts), sorbent enhancement additives (SEAs) (a proprietary EERC additive, trona, and limestone), and blending with a Powder River Basin (PRB) subbituminous coal. These Hg control technologies were evaluated separately, and many were also tested in combination.
Date: March 29, 2009
Creator: Laumb, Jason; Kay, John; Jones, Michael; Pavlish, Brandon; Lentz, Nicholas; McCollor, Donald et al.
Object Type: Text
System: The UNT Digital Library
Chemical Analysis of Impurity Boron Atoms in Diamond Using Soft X-ray Emission Spectroscopy (open access)

Chemical Analysis of Impurity Boron Atoms in Diamond Using Soft X-ray Emission Spectroscopy

To analyze the local structure and/or chemical states of boron atoms in boron-doped diamond, which can be synthesized by the microwave plasma-assisted chemical vapor deposition method (CVD-B-diamond) and the temperature gradient method at high pressure and high temperature (HPT-B-diamond), we measured the soft X-ray emission spectra in the CK and BK regions of B-diamonds using synchrotron radiation at the Advanced Light Source (ALS). X-ray spectral analyses using the fingerprint method and molecular orbital calculations confirm that boron atoms in CVD-B-diamond substitute for carbon atoms in the diamond lattice to form covalent B-C bonds, while boron atoms in HPT-B-diamond react with the impurity nitrogen atoms to form hexagonal boron nitride. This suggests that the high purity diamond without nitrogen impurities is necessary to synthesize p-type B-diamond semiconductors.
Date: March 29, 2008
Creator: Muramatsu, Yasuji; Iihara, Junji; Takebe, Toshihiko & Denlinger, Jonathan D.
Object Type: Article
System: The UNT Digital Library
Dynamic molecular imaging of cardiac innervation using a dual headpinhole SPECT system (open access)

Dynamic molecular imaging of cardiac innervation using a dual headpinhole SPECT system

Typically 123I-MIBG is used for the study of innervation andfunction of the sympathetic nervous system in heart failure. The protocolinvolves two studies: first a planar or SPECT scan is performed tomeasure initial uptake of the tracer, followed some 3-4 hours later byanother study measuring the wash-out of the tracer from the heart. A fastwash-out is indicative of a compromised heart. In this work, a dual headpinhole SPECT system was used for imaging the distribution and kineticsof 123I-MIBG in the myocardium of spontaneous hypertensive rats (SHR) andnormotensive Wistar Kyoto (WKY) rats. The system geometry was calibratedbased on a nonlinear point projection fitting method using a three-pointsource phantom. The angle variation effect of the parameters was modeledwith a sinusoidal function. A dynamic acquisition was performed byinjecting 123I-MIBG into rats immediately after starting the dataacquisition. The detectors rotated continuously performing a 360o dataacquisition every 90 seconds. We applied the factor analysis (FA)methodand region of interest (ROI) sampling method to obtain time activitycurves (TACs)in the blood pool and myocardium and then appliedtwo-compartment modeling to estimate the kinetic parameters. Since theinitial injection bolus is too fast for obtaining a consistenttomographic data set in the first few minutes of the study, we appliedthe FA method directly …
Date: March 29, 2008
Creator: Hu, Jicun; Boutchko, Rostyslav; Sitek, Arkadiusz; Reutter, BryanW.; Huesman, Ronald H. & Gullberg, Grant T.
Object Type: Report
System: The UNT Digital Library
Recent Advances on Hydrogenic Retention in ITER's Plasma-Facing Materials: BE, C, W. (open access)

Recent Advances on Hydrogenic Retention in ITER's Plasma-Facing Materials: BE, C, W.

Management of tritium inventory remains one of the grand challenges in the development of fusion energy and the choice of plasma-facing materials is a key factor for in-vessel tritium retention. The Atomic and Molecular Data Unit of the International Atomic Energy Agency organized a Coordinated Research Project (CRP) on the overall topic of tritium inventory in fusion reactors during the period 2001-2006. This dealt with hydrogenic retention in ITER's plasma-facing materials, Be, C, W, and in compounds (mixed materials) of these elements as well as tritium removal techniques. The results of the CRP are summarized in this article together with recommendations for ITER. Basic parameters of diffusivity, solubility and trapping in Be, C and W are reviewed. For Be, the development of open porosity can account for transient hydrogenic pumping but long term retention will be dominated by codeposition. Codeposition is also the dominant retention mechanism for carbon and remains a serious concern for both Be and C containing layers. Hydrogenic trapping in unirradiated tungsten is low but will increase with ion and neutron damage. Mixed materials will be formed in a tokamak and these can also retain significant amounts of hydrogen isotopes. Oxidative and photon-based techniques for detritiation of …
Date: March 29, 2008
Creator: Skinner, C H; Alimov, Kh; Bekris, N; Causey, R A; Clark, R.E.H.; Coad, J P et al.
Object Type: Report
System: The UNT Digital Library
Direct contact vs. solvent-shared ion pairs in nicl2 electrolytesmonitored by multiplet effects at the ni(ii) l-edge x-ray absorptionDOC_XNOTE=Published by BESSY, Germany in collaboration with LawrenceBerkeley National Laboratory staff. (open access)

Direct contact vs. solvent-shared ion pairs in nicl2 electrolytesmonitored by multiplet effects at the ni(ii) l-edge x-ray absorptionDOC_XNOTE=Published by BESSY, Germany in collaboration with LawrenceBerkeley National Laboratory staff.

We investigate the local electronic structure in aqueous NiCl{sub 2} electrolytes by Ni L edge x-ray absorption spectroscopy. The experimental findings are interpreted in conjunction with multiplet calculations of the electronic structure and the resulting spectral shape. In contrast to the situation in the solid, the electronic structure in the electrolyte reflects the absence of direct contact Ni-Cl ion pairs. We observe a systematic change of the intensity ratio of singlet and triplet-related spectral features as a function of electrolyte concentration. These changes can be described theoretically by a changed weight of transition matrix contributions with different symmetry. We interpret these findings as being due to progressive distortions of the local symmetry induced by solvent-shared ion pairs.
Date: March 29, 2007
Creator: Aziz, Emad F.; Eisebitt, Stefan; Eberhardt, Wolfgang; de Groot, Frank; Chiou, Jau W.; Dong, Chungi L. et al.
Object Type: Article
System: The UNT Digital Library
Dynamic Data-Driven Event Reconstruction for Atmospheric Releases (open access)

Dynamic Data-Driven Event Reconstruction for Atmospheric Releases

Accidental or terrorist releases of hazardous materials into the atmosphere can impact large populations and cause significant loss of life or property damage. Plume predictions have been shown to be extremely valuable in guiding an effective and timely response. The two greatest sources of uncertainty in the prediction of the consequences of hazardous atmospheric releases result from poorly characterized source terms and lack of knowledge about the state of the atmosphere as reflected in the available meteorological data. We have developed a new event reconstruction methodology that provides probabilistic source term estimates from field measurement data for both accidental and clandestine releases. Accurate plume dispersion prediction requires the following questions to be answered: What was released? When was it released? How much material was released? Where was it released? We have developed a dynamic-data-driven event reconstruction capability that couples data and predictive methods through Bayesian inference to obtain a solution to this inverse problem. The solution consists of a probability distribution of unknown source term parameters. For consequence assessment, we then use this probability distribution to construct a 'composite' forward plume prediction that accounts for the uncertainties in the source term. Since in most cases of practical significance it is …
Date: March 29, 2007
Creator: Mirin, A. A. & Kosovic, B.
Object Type: Report
System: The UNT Digital Library
Eclipsing binary stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample (open access)

Eclipsing binary stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample

We present a new sample of 4634 eclipsing binary stars in the Large Magellanic Cloud (LMC), expanding on a previous sample of 611 objects and a new sample of 1509 eclipsing binary stars in the Small Magellanic Cloud (SMC), that were identified in the light curve database of the MACHO project. We perform a cross correlation with the OGLE-II LMC sample, finding 1236 matches. A cross correlation with the OGLE-II SMC sample finds 698 matches. We then compare the LMC subsamples corresponding to center and the periphery of the LMC and find only minor differences between the two populations. These samples are sufficiently large and complete that statistical studies of the binary star populations are possible.
Date: March 29, 2007
Creator: Faccioli, L.; Alcock, C.; Cook, K.; Prochter, G.; Protopapas, P. & Syphers, D.
Object Type: Article
System: The UNT Digital Library
HYDROGEN INITIATIVE: AN INTEGRATED APPROACH TOWARD RATIONAL NANOCATALYST DESIGN FOR HYDROGEN PRODUCTION. Technical Report-Year 1 (open access)

HYDROGEN INITIATIVE: AN INTEGRATED APPROACH TOWARD RATIONAL NANOCATALYST DESIGN FOR HYDROGEN PRODUCTION. Technical Report-Year 1

The overall objective of this grant is to develop a rational framework for the discovery of low cost, robust, and active nano-catalysts that will enable efficient hydrogen production. Our approach will be the first demonstration of integrated multiscale model, nano-catalyst synthesis, and nanoscale characterization assisted high throughput experimentation (HTE). We will initially demonstrate our approach with ammonia decomposition on noble metal catalysts. Our research focuses on many elements of the Hydrogen Initiative in the Focus Area of “Design of Catalysts at the Nanoscale’. It combines high-throughput screening methods with various nanostructure synthesis protocols, advanced measurements, novel in situ and ex situ characterization techniques, and multiscale theory, modeling and simulation. This project directly addresses several of the long-term goals of the DOE/BES program. In particular, new nanoscale catalytic materials will be synthesized, characterized and modeled for the production of hydrogen from ammonia and a computational framework will be developed for efficient extraction of information from experimental data and for rational design of catalysts whose impact goes well beyond the proposed hydrogen production project. In the first year of the grant, we have carried out HTE screening using a 16 parallel microreactor coupled with an FTIR analysis system. We screened nearly twenty …
Date: March 29, 2007
Creator: Vlachos, Dionisios G; Buttrey, Douglas J & Lauterbach, Jochen
Object Type: Report
System: The UNT Digital Library
K(alpha) X-ray Emission Spectra from Highly Charged Fe Ions in EBIT (open access)

K(alpha) X-ray Emission Spectra from Highly Charged Fe Ions in EBIT

A detailed spectral model has been developed for the computer simulation of the 2p {yields} 1s K{alpha} X-ray emission from highly charged Fe ions in the Electron Beam Ion Trap (EBIT). The spectral features of interest occur in the range from 1.84 {angstrom} to 1.94 {angstrom}. The fundamental radiative emission processes associated with radiationless electron capture or dielectronic recombination, inner-shell electron collisional excitation, and inner-shell electron collisional ionization are taken in account. For comparison, spectral observations and simulations for high-temperature magnetic-fusion (Tokamak) plasmas are reviewed. In these plasmas, small departures from steady-state corona-model charge-state distributions can occur due to ion transport processes, while the assumption of equilibrium (Maxwellian) electron energy distributions is expected to be valid. Our investigations for EBIT have been directed at the identification of spectral features that can serve as diagnostics of extreme non-equilibrium or transient-ionization conditions, and allowance has been made for general (non-Maxwellian) electron energy distributions. For the precise interpretation of the high-resolution X-ray observations, which may involve the analysis of blended spectral features composed of many lines, it has been necessary to take into account the multitude of individual fine-structure components of the K{alpha} radiative transitions in the ions from Fe XVIII to Fe …
Date: March 29, 2007
Creator: Jacobs, V & Beiersdorfer, P
Object Type: Article
System: The UNT Digital Library
On-Line Oxidation of Volatile Organic Compounds Generated by Sawmill Wood Kilns (open access)

On-Line Oxidation of Volatile Organic Compounds Generated by Sawmill Wood Kilns

The primary purpose of this project was to evaluate the effectiveness of the use of hydrogen peroxide in combination with ultra-violet (UV) light for the reduction in the amount of volatile organic compounds (VOC’s) released into the environment during wood drying in sawmill kilns. As originally envisioned the scope of work included the optimization of reaction parameters i.e. pH, peroxide concentration, UV light intensity that would lead to successful destruction of VOC’s. The second phase involved development of a prototypical reactor that could be taken to a sawmill kiln for demonstration of treatment of a slipstream. However, after some of our initial experiments, we were forced to limit ourselves to more modest testing and development. During the project period we designed and constructed a small-scale reactor that was connected to the off-gas from a small wood drying kiln located at the Forest Products Lab at Mississippi State University. We ran a number of tests where we varied the process parameters (peroxide concentration, pH and UV light intensity) with no reasonable amount of VOC destruction. We employed a number of ways to atomize the peroxide into the kiln off-gas including using Laskin nozzles to see if that would improve the VOC …
Date: March 29, 2007
Creator: Kumar, R. Arun; Steele, Philip & Patterson, W. Dean
Object Type: Report
System: The UNT Digital Library
POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS (open access)

POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the material transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 …
Date: March 29, 2007
Creator: Eibling, R; Erich Hansen, E & Bradley Pickenheim, B
Object Type: Report
System: The UNT Digital Library
Science & Technology Review May 2007 (open access)

Science & Technology Review May 2007

None
Date: March 29, 2007
Creator: Radousky, H. B.
Object Type: Report
System: The UNT Digital Library
Advances in Electromagnetic Modelling through High Performance Computing (open access)

Advances in Electromagnetic Modelling through High Performance Computing

Under the DOE SciDAC project on Accelerator Science and Technology, a suite of electromagnetic codes has been under development at SLAC that are based on unstructured grids for higher accuracy, and use parallel processing to enable large-scale simulation. The new modeling capability is supported by SciDAC collaborations on meshing, solvers, refinement, optimization and visualization. These advances in computational science are described and the application of the parallel eigensolver Omega3P to the cavity design for the International Linear Collider is discussed.
Date: March 29, 2006
Creator: Ko, K.; Folwell, N.; Ge, L.; Guetz, A.; Lee, L.; Li, Z. et al.
Object Type: Report
System: The UNT Digital Library
Argonne National Laboratory Summary Site Environmental Report for Calendar Year 2004. (open access)

Argonne National Laboratory Summary Site Environmental Report for Calendar Year 2004.

This report talks about Argonne National Laboratory summary site environmental report for calendar year 2004
Date: March 29, 2006
Creator: Golchert, N. W.
Object Type: Report
System: The UNT Digital Library
Beam Losses in the Extraction Line of a TeV E+ E- Linear Collider With a 20-Mrad Crossing Angle (open access)

Beam Losses in the Extraction Line of a TeV E+ E- Linear Collider With a 20-Mrad Crossing Angle

In this paper, we perform a detailed study of the power losses along the postcollision extraction line of a TeV e+e- collider with a crossing angle of 20 mrad between the beams at the interaction point. Five cases are considered here: four luminosity configurations for ILC and one for CLIC. For all of them, the strong beam-beam effects at the interaction point lead to an emittance growth for the outgoing beams, as well as to the production of beamstrahlung photons and e+e- pairs. The power losses along the 20 mrad extraction line, which are due to energy deposition by a fraction of the disrupted beam, of the beamstrahlung photons and of the e+e- coherent pairs, were estimated in the case of ideal collisions, as well as with a vertical position or angular o set at the interaction point.
Date: March 29, 2006
Creator: Ferrari, A.; U., /Uppsala & Nosochkov, Y.
Object Type: Report
System: The UNT Digital Library
Borehole Data Package for One CY 2005 CERCLA Well 699-S20-E10, 300-FF-5 Operable Unit, Hanford Site, Washington (open access)

Borehole Data Package for One CY 2005 CERCLA Well 699-S20-E10, 300-FF-5 Operable Unit, Hanford Site, Washington

This report supplies the information obtained during drilling, characterization, and installation of the new groundwater monitoring well. This document also provides a compilation of hydrogeologic and well construction information obtained during drilling, well development, and sample collection/analysis activities.
Date: March 29, 2006
Creator: Williams, Bruce A.; Bjornstad, Bruce N.; Lanigan, David C.; Keller, Jason M. & Rockhold, Mark L.
Object Type: Report
System: The UNT Digital Library
Final Report: Developing Liquid Protection Schemes for Fusion Energy Reactor First Walls (open access)

Final Report: Developing Liquid Protection Schemes for Fusion Energy Reactor First Walls

Over the last year, the Georgia Tech group has experimentally studied vertical turbulent sheets of water issuing downwards into atmospheric pressure air at Reynolds numbers Re = U{sub 0}{delta}/{nu} = 53,000 and 120,000 and Weber numbers We = {rho}U{sub o} {sup 2}{delta}/{sigma} = 2,900 and 18,000, respectively. Here, U{sub o} is the average jet speed, {delta} is the jet thickness (short dimension) at the nozzle exit ({delta} = 1 cm), and {nu}, {rho} and {sigma} are the kinematic viscosity and density of water and the surface tension at the air-water interface, respectively. These Re and We values are about 50% and 20% of the prototypical values for HYLIFE-II, respectively. In this report, the flow coordinate system is defined so that the origin is at the center of the nozzle exit, with the x-axis along the flow direction, the y-axis along the long dimension of the nozzle, and the z-axis along the short dimension of the nozzle (cf. Fig. 1). During the final year of this project, we have made three contributions in the area of thermal-hydraulics of thick liquid protection, namely: (1) Experimentally demonstrated that removing as little as 1% of the total mass flux using boundary-layer (BL) cutting can …
Date: March 29, 2006
Creator: Abdel-Khalik, Minami Yoda Said I.
Object Type: Report
System: The UNT Digital Library
In-Situ Cleaning of Metal Cathodes using a Hydrogen Ion Beam (open access)

In-Situ Cleaning of Metal Cathodes using a Hydrogen Ion Beam

Metal photocathodes are commonly used in high-field RF guns because they are robust, straightforward to implement and tolerate relatively poor vacuum compared to semi-conductor cathodes. However these cathodes have low quantum efficiency (QE) even at UV wavelengths, and still require some form of cleaning after installation in the gun. A commonly used process for improving the QE is laser cleaning. In this technique the UV drive laser is focused to a small diameter close to the metal's damage threshold and then moved across the surface to remove contaminants. This method does improve the QE, but can produce non-uniform emission and potentially damage the cathode. Ideally an alternative process which produces an atomically clean, but unaltered surface is needed. In this paper we explore using a hydrogen ion (H-ion) beam to clean a copper cathode. We describe QE measurements over the wavelength range of interest as a function of integrated exposure to an H-ion beam. We also describe the data analysis to obtain the work function and derive a formula of the QE for metal cathodes. Our measured work function for the cleaned sample is in good agreement with published values, and the theoretical QE as a function of photon wavelength …
Date: March 29, 2006
Creator: Dowell, D. H.; King, F. K.; Kirby, R. E. & Schmerge, J. F.
Object Type: Report
System: The UNT Digital Library
Membrane composition analysis by imaging mass spectrometry (open access)

Membrane composition analysis by imaging mass spectrometry

Membranes on solid supports offer an ideal format for imaging. Secondary ion mass spectrometry (SIMS) can be used to obtain composition information on membrane-associated components. Using the NanoSIMS50, images of composition variations in membrane domains can be obtained with a lateral resolution better than 100 nm. By suitable calibration, these variations in composition can be translated into a quantitative analysis of the membrane composition. Progress towards imaging small phase-separated lipid domains, membrane-associated proteins and natural biological membranes will be described.
Date: March 29, 2006
Creator: Boxer, S G; Kraft, M L; Longo, M; Hutcheon, I D & Weber, P K
Object Type: Article
System: The UNT Digital Library
Nb-Pb Superconducting RF Gun (open access)

Nb-Pb Superconducting RF Gun

We report on the status of an electron RF-gun made of two superconductors: niobium and lead. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead, as compared to other superconducting metals. The concept, mentioned in a previous paper, follows the attractive approach of all niobium superconducting RF-gun as it has been proposed by the BNL group. Measured values of quantum efficiency for lead at various photon energies, analysis of recombination time of photon-broken Cooper pairs for lead and niobium, and preliminary cold test results are discussed in this paper.
Date: March 29, 2006
Creator: Sekutowicz, J.; Iversen, J.; Kreps, G.; Moller, W. D.; Singer, W.; Singer, X. et al.
Object Type: Report
System: The UNT Digital Library
Nuclear Gamma-Ray Spectroscopy at the Limit of Particle Spectroscopy (open access)

Nuclear Gamma-Ray Spectroscopy at the Limit of Particle Spectroscopy

The research project ''Nuclear Gamma-Ray Spectroscopy at the Limit of Particle Stability'' with sponsor ID ''DE-FG02-04ER41334'' started late-summer 2004 and aims at the investigation of highly excited low-spin states of selected key-nuclei in the vicinity of the particle separation threshold by means of high-resolution gamma-ray spectroscopy in electromagnetic excitation reactions. This work addresses nuclear structures with excitation energies close to the binding energy or highly excited off-yrast states in accordance with the NSAC milestones. In 2005 the program was extended towards additional use of virtual photons and theoretical description of the low-lying collective excitations in the well deformed nuclei.
Date: March 29, 2006
Creator: Pietralla, Dr. Norbert
Object Type: Report
System: The UNT Digital Library
Observation of a Charmed Baryon Decaying to D0 p at a Mass Near 2.94 GeV/c2 (open access)

Observation of a Charmed Baryon Decaying to D0 p at a Mass Near 2.94 GeV/c2

A search for charmed baryons decaying to D{sup 0}p reveals two states: the {Lambda}{sub c}(2880){sup +} baryon and a previously unobserved state at a mass of [2939.8 {+-} 1.3 (stat.) {+-} 1.0 (syst.)] MeV/c{sup 2} and with an intrinsic width of [17.5 {+-} 5.2 (stat.) {+-} 5.9 (syst.)] MeV. Consistent and significant signals are observed for the K{sup -}{pi}{sup +} and K{sup -}{pi}{sup +}{pi}{sup -}{pi}{sup +} decay modes of the D{sup 0} in 287 fb{sup -1} annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D{sup +}p spectrum of doubly-charged partners. The mass and intrinsic width of the {Lambda}{sub c}(2880){sup +} baryon and relative yield of the two baryons are also measured.
Date: March 29, 2006
Creator: Aubert, B.
Object Type: Report
System: The UNT Digital Library
Quarterly progress report for Q2 FY06 for Complex Transient Events in Materials Studied Using Ultrafast Electron Probes and Terascale Simulation (FWP SCW0289) (open access)

Quarterly progress report for Q2 FY06 for Complex Transient Events in Materials Studied Using Ultrafast Electron Probes and Terascale Simulation (FWP SCW0289)

In this quarter (Q2 FY06), the DTEM underwent a substantial reconfiguration of its laser systems. The cathode laser system was changed to provide greater numbers of electrons per pulse by lengthening the time duration of the pulse to 30 ns. The greater number of electrons per pulse has allowed us to acquire high quality pulsed images and diffraction patterns. The spatial resolution in the single pulsed image has been measured at better than 20 nm. The diffraction patterns are now more comparable to conventional electron microscope operation. Examples are found in the body of the report. We summarize important achievements in the following list: (1) Instrument performance and design improvements--(A) The laser system was changed for the cathode photoemission system (75 ns at 1053 nm wavelength converted to 30ns at 211 nm wavelength) to give longer electron pulses at the same current to yield more electrons per pulse. (B) New specimen drive laser constructed. (C) New computer monitored and controlled alignment systems installed for both laser systems to facilitate laser alignment through a user friendly computer interface. (2) Experimental Progress--(A) The spatial resolution of pulsed images was tested by imaging a cross-section of multilayer thin foils with 30 nm and …
Date: March 29, 2006
Creator: Campbell, G. H.
Object Type: Report
System: The UNT Digital Library
The Scientific Publications of Richard H. Dalitz, FRS (1925-2006) (open access)

The Scientific Publications of Richard H. Dalitz, FRS (1925-2006)

Professor Richard H. Dalitz passed away on January 13, 2006. He was almost 81 years old and his outstanding contributions are intimately connected to some of the major breakthroughs of the 20th century in particle and nuclear physics. These outstanding contributions go beyond the Dalitz Plot, Dalitz Pair and CDD poles that bear his name. He pioneered the theoretical study of strange baryon resonances, of baryon spectroscopy in the quark model, and of hypernuclei, to all of which he made lasting contributions. His formulation of the ''{theta} - {tau} puzzle'' led to the discovery that parity is not a symmetry of the weak interactions. A brief scientific evaluation of Dalitz's major contributions to particle and nuclear physics is hereby presented, followed by the first comprehensive list of his scientific publications, as assembled from several sources. The list is divided into two categories: the first, main part comprises Dalitz's research papers and reviews, including topics in the history of particle physics, biographies and reminescences; the second part lists book reviews, public lectures and obituaries authored by Dalitz, and books edited by him. This provides the first necessary step towards a more systematic research of the Dalitz heritage in modern physics.
Date: March 29, 2006
Creator: Aitchison, Ian J.R.; Close, Frank E.; Gal, Avraham & Millener, D.John
Object Type: Report
System: The UNT Digital Library