Weak interaction effects in e/sup +/e/sup -/ annihilation with polarised beams (open access)

Weak interaction effects in e/sup +/e/sup -/ annihilation with polarised beams

Although the standard gauge model of weak and electromagnetic interactions based on the work of Salam and Weinberg has met with great success, there are experimental facts that will require its extension or its modification to a new gauge model; the discovery of a heavy lepton at SLAC and the absence of parity violation in atoms that is expected from the neutral weak current coupling to electrons are discussed. Three tests are proposed that bear on these questions. First, heavy lepton production in e/sup +/e/sup -/ annihilation when one of the incident beams is longitudinally polarized is considered and the purely leptonic decay of this heavy lepton is examined. An asymmetry in the inclusive angular distribution of one charged lepton (electron or muon) is important in determining the structure of weak interactions of the heavy lepton. In fact, this angular asymmetry easily distinguishes between the cases V - A and V + A for the heavy lepton current. Then, the decay channel L ..-->.. ..nu../sub L/ + one hadron is considered (L = heavy lepton) under the same experimental set-up and the inclusive one-hadron angular distribution examined. Parity nonconservation in the decay of the heavy lepton causes a conspicuous forward-backward …
Date: November 2, 1977
Creator: Simard, R.
Object Type: Report
System: The UNT Digital Library
Engineering problems in the development of fusion power reactors (open access)

Engineering problems in the development of fusion power reactors

This paper reviews current progress in the development of fusion power from the engineering point of view and highlights the most outstanding technical issues which must be resolved. (MOW)
Date: November 2, 1976
Creator: Varljen, T. C.
Object Type: Article
System: The UNT Digital Library
Design issues for a laboratory high gain fusion facility (open access)

Design issues for a laboratory high gain fusion facility

In an inertial fusion laboratory high gain facility, experiments will be carried out with up to 1000 MJ of thermonuclear yield. The experiment area of such a facility will include many systems and structures that will have to operate successfully in the difficult environment created by the sudden large energy release. This paper estimates many of the nuclear effects that will occur, discusses the implied design issues and suggests possible solutions so that a useful experimental facility can be built. 4 figs.
Date: November 2, 1987
Creator: Hogan, W.J.
Object Type: Article
System: The UNT Digital Library
OCR vision system, an alternative to bar code (open access)

OCR vision system, an alternative to bar code

This report describes optical character reader system advantages and applications. Comparisons are made to bar code readers. (JDH)
Date: November 2, 1987
Creator: Leader, D R
Object Type: Article
System: The UNT Digital Library
The relation of electrode voltages to charge position in SLC arc and final focus beam position monitors (open access)

The relation of electrode voltages to charge position in SLC arc and final focus beam position monitors

The position of a charged particle beam can be measured with a Beam Position Monitor (BPM) by converting the voltages induced on its array of electrodes into a position offset from the array's center. Most of the BPMs in the Arcs and Final Focus of the SLC use four stripline electrodes arranged symmetrically around the beam; normalized voltage differences are calculated as the difference divided by the sum of voltages on opposite electrode pairs. The resulting number is multiplied by a conversion factor, denoted in this paper as S{sub b}, to give the offset (in millimeters) of the charge from the center of the BPM. Prior to installation in the beam line, the BPMs were calibrated with a charge pulse on a rod. Owing to geometric effects which will be discussed later, a different conversion factor had to be used for calibration. It will be denoted here by S{sub r}. This paper gives the results of calculations and measurements of S{sub r} and S{sub b} for Arc and Final Focus BPMs. This paper also describes the relevant physical properties of the several types of BPMs and calculations of the expected scale factors, the measurement methods used, and gives the results …
Date: November 2, 1989
Creator: Fordham, C.
Object Type: Report
System: The UNT Digital Library
Concentrating-collector mass-production feasibility. Volume I. Final report (open access)

Concentrating-collector mass-production feasibility. Volume I. Final report

The Performance Prototype Trough (PPT) Concentrating Collector consists of four 80-foot modules in a 320-foot row. The collector was analyzed, including cost estimates and manufacturing processes to produce collectors in volumes from 100 to 100,000 modules per year. The four different reflector concepts considered were the sandwich reflector structure, sheet metal reflector structure, molded reflector structure, and glass laminate structure. The sheet metal and glass laminate structures are emphasized with their related structure concepts. A preliminary manufacturing plan is offered that includes: documentation of the manufacturing process with production flow diagrams; labor and material costs at various production levels; machinery and equipment requirements including preliminary design specifications; and capital investment costs for a new plant. Of five reflector designs considered, the two judged best and considered at length are thin annealed glass and steel laminate on steel frame panel and thermally sagged glass. Also discussed are market considerations, costing and selling price estimates, design cost analysis and make/buy analysis. (LEW)
Date: November 2, 1981
Creator: unknown
Object Type: Report
System: The UNT Digital Library
TIBER II/ETR (Engineering Test Reactor) nuclear shielding and optional tritium breeding system: An overview (open access)

TIBER II/ETR (Engineering Test Reactor) nuclear shielding and optional tritium breeding system: An overview

TIBER II, the Tokamak Ignition/Burn Experimental Reactor II, is a design concept developed as the US candidate for an International Engineering Test Reactor (ETR). An important objective of this design is to minimize cost by minimizing major radius while providing a wall loading greater than 1.0 MW/m2 and a total fluence greater than 3.0 MWY/m2 needed for blanket module testing. The shielding required for the superconducting TF coils is an important element in setting TIBER II's 3.0m major radius. 6 refs., 1 fig., 1 tab.
Date: November 2, 1987
Creator: Lee, J. D. & Sawan, M.
Object Type: Article
System: The UNT Digital Library
Verifying the Cosmological Utility of Type Ia Supernovae:Implications of a Dispersion in the Ultraviolet Spectra (open access)

Verifying the Cosmological Utility of Type Ia Supernovae:Implications of a Dispersion in the Ultraviolet Spectra

We analyze the mean rest-frame ultraviolet (UV) spectrum ofType Ia Supernovae(SNe) and its dispersion using high signal-to-noiseKeck-I/LRIS-B spectroscopyfor a sample of 36 events at intermediateredshift (z=0.5) discoveredby the Canada-France-Hawaii TelescopeSupernova Legacy Survey (SNLS). Weintroduce a new method for removinghost galaxy contamination in our spectra,exploiting the comprehensivephotometric coverage of the SNLS SNe and theirhost galaxies, therebyproviding the first quantitative view of the UV spectralproperties of alarge sample of distant SNe Ia. Although the mean SN Ia spectrumhas notevolved significantly over the past 40 percent of cosmic history,preciseevolutionary constraints are limited by the absence of acomparable sample ofhigh quality local spectra. The mean UV spectrum ofour z 0.5 SNe Ia and itsdispersion is tabulated for use in futureapplications. Within the high-redshiftsample, we discover significant UVspectral variations and exclude dust extinctionas the primary cause byexamining trends with the optical SN color. Although progenitormetallicity may drive some of these trends, the variations we see aremuchlarger than predicted in recent models and do not follow expectedpatterns.An interesting new result is a variation seen in the wavelengthof selected UVfeatures with phase. We also demonstrate systematicdifferences in the SN Iaspectral features with SN lightcurve width inboth the UV and the optical. Weshow that these intrinsic variations couldrepresent …
Date: November 2, 2007
Creator: Ellis, R. S.; Sullivan, M.; Nugent, P. E.; Howell, D. A.; Gal-Yam, A.; Astier, P. et al.
Object Type: Article
System: The UNT Digital Library
Fault Geomechanics and Carbon Dioxide Leakage Applied to Geological Storage: FY07 Quarterly and Summary Reports (open access)

Fault Geomechanics and Carbon Dioxide Leakage Applied to Geological Storage: FY07 Quarterly and Summary Reports

Safe and permanent storage of carbon dioxide in geologic reservoirs is critical to geologic sequestration. The objective of this study is to quantify the conditions under which a general (simulated) fault network and a specific (field case) fault network will fail and leak carbon dioxide out of a reservoir. Faults present a potential fast-path for CO{sub 2} leakage from reservoirs to the surface. They also represent potential induced seismicity hazards. It is important to have improved quantitative understandings of the processes that trigger activity on faults and the risks they present. Fortunately, the conditions under which leakage along faults is induced can be predicted and quantified given the fault geometry, reservoir pressure, an in-situ stress tensor. We proposed to expand the current capabilities of fault threshold characterization and apply that capability to a site where is CO{sub 2} injection is active or planned. Specifically, we proposed to use a combination of discrete/explicit and continuum/implicit codes to provide constrain the conditions of fault failure. After minor enhancements of LLNL's existing codes (e.g., LDEC), we would create a 3D synthetic model of a common configuration (e.g., a faulted dome). During these steps, we will identify a field site where the necessary information …
Date: November 2, 2007
Creator: Friedmann, S. J. & Morris, J.
Object Type: Report
System: The UNT Digital Library
John B. Little Center Annual Symposium (open access)

John B. Little Center Annual Symposium

The Annual Symposium of the John B. Little Center for Radiation Sciences and Environmental Health at the Harvard School of Public Health seeks to educate radiobiologists and biomedical scientists in related areas on the leading research related to the effects of ionizing radiation and related environmental agents in biological systems. This effort seeks to further the training of individuals in this field, and to foment productive interactions and collaborations among scientists at Harvard and with other institutions. The Symposium attracts world-class scientists as speakers, and a broad cross-section of attendees from academic, government, and industrial research centers, as well as editorial staff from leading scientific publications. In order to maintain this quality, funding to support the travel and local expenses of invited speakers is sought, along with funds to allow use of appropriate conference facilities.
Date: November 2, 2007
Creator: Demple, Bruce F.
Object Type: Report
System: The UNT Digital Library
Laboratory measurements on core-scale sediment/hydrate samples topredice reservoir behavior (open access)

Laboratory measurements on core-scale sediment/hydrate samples topredice reservoir behavior

Measurements on hydrate-bearing laboratory and field samplesare necessary in order to provide realistic bounds on parameters used innumerically modeling the production of natural gas from hydrate-bearingreservoirs. The needed parameters include thermal conductivity,permeability, relative permeability-saturation(s) relationships, andcapillary pressure-saturation(s) relationships. We have developed atechnique to make hydrate-bearing samples ranging in scale from coreplug-size to core-size in the laboratory to facilitate making thesemeasurements. In addition to pressure and temperature measurements, weuse x-ray computed tomography scanning to provide high-resolution dataproviding insights on processes occurring in our samples. Several methodsare available to make gas hydrates in the laboratory, and we expect thatthe method used to make the hydrate will impact the behavior of thehydrate sample, and the parameters measured.
Date: November 2, 2005
Creator: Kneafsey, Timothy J.; Seol, Yongkoo; Moridis, George J.; Tomutsa,Liviu & Freifeld, Barry M.
Object Type: Report
System: The UNT Digital Library
Incorporating anisotropic electronic structure in crystallographic determination of complex metals: iron and plutonium (open access)

Incorporating anisotropic electronic structure in crystallographic determination of complex metals: iron and plutonium

None
Date: November 2, 2005
Creator: Moore, K; Laughlin, D; Soderlind, P & Schwartz, A
Object Type: Article
System: The UNT Digital Library
Cleanup Verification Package for the 118-F-7, 100-F Miscellaneous Hardware Storage Vault (open access)

Cleanup Verification Package for the 118-F-7, 100-F Miscellaneous Hardware Storage Vault

This cleanup verification package documents completion of remedial action for the 118-F-7, 100-F Miscellaneous Hardware Storage Vault. The site consisted of an inactive solid waste storage vault used for temporary storage of slightly contaminated reactor parts that could be recovered and reused for the 100-F Area reactor operations.
Date: November 2, 2006
Creator: Appel, M. J.
Object Type: Report
System: The UNT Digital Library
Transmission Electron Microscopy Characterization of Helium Bubbles in Aged Plutonium (open access)

Transmission Electron Microscopy Characterization of Helium Bubbles in Aged Plutonium

The self-irradiation damage generated by alpha decay of plutonium results in the formation of lattice defects, helium, and uranium atoms. Over time, microstructural evolution resulting from the self-irradiation may influence the physical and mechanical properties of the material. In order to assess microstructural changes, we have developed and applied procedures for the specimen preparation, handling, and transmission electron microscopy characterization of Pu alloys. These transmission electron microscopy investigations of Pu-Ga alloys ranging in age up to 42-years old reveal the presence of nanometer-sized helium bubbles. The number density of bubbles and the average size have been determined for eight different aged materials.
Date: November 2, 2004
Creator: Schwartz, A J; Wall, M A; Zocco, T G & Blobaum, K M
Object Type: Article
System: The UNT Digital Library
Proceedings of the 18th Annual Conference on Fossil Energy Materials. (open access)

Proceedings of the 18th Annual Conference on Fossil Energy Materials.

The 18th Annual conference on Fossil Energy Materials was held in Knoxville, Tennessee, on June 2 through June 4, 2004. The meeting was sponsored by the U.S. Department of Energy's (DOE) Office of Fossil Energy through the Advanced Research Materials Program (ARM). The objective of the ARM Program is to conduct research and development on materials for longer-term fossil energy applications, as well as for generic needs of various fossil fuel technologies. The management of the program has been decentralized to the DOE Oak Ridge Operations Office and Oak Ridge National Laboratory (ORNL). The research is performed by staff members at ORNL and by researchers at other national laboratories, universities, and in private industry. The work is divided into the following categories: (1) structural, ceramics, (2) new alloys and coatings, (3) functional materials, and (4) technology development and transfer.
Date: November 2, 2004
Creator: Judkins, RR
Object Type: Report
System: The UNT Digital Library
MRF Applications: Measurement of Process-dependent Subsurface Damage in Optical Materials using the MRF Wedge Technique (open access)

MRF Applications: Measurement of Process-dependent Subsurface Damage in Optical Materials using the MRF Wedge Technique

Understanding the behavior of fractures and subsurface damage in the processes used during optic fabrication plays a key role in determining the final quality of the optical surface finish. During the early stages of surface preparation, brittle grinding processes induce fractures at or near an optical surface whose range can extend from depths of a few mm to hundreds of mm depending upon the process and tooling being employed. Controlling the occurrence, structure, and propagation of these sites during subsequent grinding and polishing operations is highly desirable if one wishes to obtain high-quality surfaces that are free of such artifacts. Over the past year, our team has made significant strides in developing a diagnostic technique that combines magnetorheological finishing (MRF) and scanning optical microscopy to measure and characterize subsurface damage in optical materials. The technique takes advantage of the unique nature of MRF to polish a prescribed large-area wedge into the optical surface without propagating existing damage or introducing new damage. The polished wedge is then analyzed to quantify subsurface damage as a function of depth from the original surface. Large-area measurement using scanning optical microscopy provides for improved accuracy and reliability over methods such as the COM ball-dimple technique. …
Date: November 2, 2005
Creator: Menapace, J A; Davis, P J; Steele, W A; Wong, L L; Suratwala, T I & Miller, P E
Object Type: Article
System: The UNT Digital Library
Growth of thick, crystalline material using dc-magnetron sputtering in Mag1 deposition chamber (open access)

Growth of thick, crystalline material using dc-magnetron sputtering in Mag1 deposition chamber

We demonstrated dense, non-columnar growth of thick Mo films by moving the substrates in and out of the plasma thus allowing the surface reconstruction and by interrupting the growth with Si layers. The multilayers made this way have very smooth surface, about 1.3 nm rms high spatial frequency roughness, while also maintaining the periodicity of a reflective coating. These preliminary results hint that the surface reconstruction is an important physical process that controls the growth mechanisms. Further studies, combined with theoretical modeling, are essential to further our knowledge on how to predict and control desired microstructure for different materials.
Date: November 2, 2005
Creator: Bajt, S; Alameda, J; Baker, S & Taylor, J S
Object Type: Report
System: The UNT Digital Library
Diffusion-controlled spherulite growth in obsidian inferred from H2O concentration profiles (open access)

Diffusion-controlled spherulite growth in obsidian inferred from H2O concentration profiles

Spherulites are spherical clusters of radiating crystals that occur naturally in rhyolitic obsidian. The growth of spherulites requires diffusion and uptake of crystal forming components from the host rhyolite melt or glass, and rejection of non-crystal forming components from the crystallizing region. Water concentration profiles measured by synchrotron-source Fourier transform spectroscopy reveal that water is expelled into the surrounding matrix during spherulite growth, and that it diffuses outward ahead of the advancing crystalline front. We compare these profiles to models of water diffusion in rhyolite to estimate timescales for spherulite growth. Using a diffusion-controlled growth law, we find that spherulites can grow on the order of days to months at temperatures above the glass transition. The diffusion-controlled growth law also accounts for spherulite size distribution, spherulite growth below the glass transition, and why spherulitic glasses are not completely devitrified.
Date: November 2, 2007
Creator: Watkins, Jim; Watkins, Jim; Manga, Michael; Huber, Christian & Martin, Michael C.
Object Type: Article
System: The UNT Digital Library
America's Atomic Army: The Historical Archaeology of Camp Desert Rock (open access)

America's Atomic Army: The Historical Archaeology of Camp Desert Rock

Established in 1951, Camp Desert Rock served as the training ground for America's 'Atomic Army'. For the next six years, U.S. ground troops traveled to the Nevada desert to participate in military maneuvers during atmospheric atomic weapons testing. Nearly 60,000 soldiers received physical and psychological training in atomic warfare. Abandoned when atmospheric testing ended, Camp Desert Rock was dismantled and its buildings moved to other locations. Today, the camp appears as a sterile expanse of desert marked by rock-lined tent platforms, concrete foundations, and trash scatters. Although visually unimposing, the site is rich with the history of America's nuclear testing program.
Date: November 2, 2007
Creator: Edwards, Susan R.
Object Type: Article
System: The UNT Digital Library
Bower Cabin (open access)

Bower Cabin

The Bower Cabin, located in southern Nevada, was built and occupied by B.M. Bower and her family during the early 1920s. Bower, a prominent writer of western novels, had over 90 novels to her credit. She wrote 11 of the stories while living at the cabin and, at times, incorporated the surrounding landscape features, including the cabin site itself, into them. The site was subsequently used by a gang of rustlers and for a mining base camp. Archaeological research has identified the remnants of the main structures at the site as well as the artifact material and nearby mining activities associated with the Bower and later occupations.
Date: November 2, 2007
Creator: Drollinger, Harold
Object Type: Article
System: The UNT Digital Library
Phenomenology of the left-right twin Higgs model (open access)

Phenomenology of the left-right twin Higgs model

The twin Higgs mechanism was proposed recently to solve the little hierarchy problem. We study the implementation of the twin Higgs mechanism in left-right models. At the TeV scale, heavy quark and gauge bosonsappear, with rich collider phenomenology. In addition, there are extra Higgs bosons, some of which couple to both the standard model fermion sector and the gauge sector, while others couple to the gauge bosons only. We present the particle spectrum and study the general features of the collider phenomenology of this class of model at the Large Hadron Collider.
Date: November 2, 2006
Creator: Goh, Hock-Seng; Goh, Hock-Seng & Su, Shufang
Object Type: Article
System: The UNT Digital Library
The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007), (open access)

The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007),

This paper bundles 40 contributions by the IceCube collaboration that were submitted to the 30th International Cosmic Ray Conference ICRC 2007. The articles cover studies on cosmic rays and atmospheric neutrinos, searches for non-localized, extraterrestrial {nu}{sub e}, {nu}{sub {mu}} and {nu}{sub {tau}} signals, scans for steady and intermittent neutrino point sources, searches for dark matter candidates, magnetic monopoles and other exotic particles, improvements in analysis techniques, as well as future detector extensions. The IceCube observatory will be finalized in 2011 to form a cubic-kilometer ice-Cherenkov detector at the location of the geographic South Pole. At the present state of construction, IceCube consists of 52 paired IceTop surface tanks and 22 IceCube strings with a total of 1426 Digital Optical Modules deployed at depths up to 2350 m. The observatory also integrates the 19 string AMANDA subdetector, that was completed in 2000 and extends IceCube's reach to lower energies. Before the deployment of IceTop, cosmic air showers were registered with the 30 station SPASE-2 surface array. IceCube's low noise Digital Optical Modules are very reliable, show a uniform response and record waveforms of arriving photons that are resolvable with nanosecond precision over a large dynamic range. Data acquisition, reconstruction and simulation …
Date: November 2, 2007
Creator: Collaboration, IceCube & Ackermann, M.
Object Type: Article
System: The UNT Digital Library
Application of MeV ions to the analysis and modification of high temperature superconducting materials (open access)

Application of MeV ions to the analysis and modification of high temperature superconducting materials

In analyzing the composition of high {Tc} superconducting materials using heavy-ion RBS we discovered that the electronic excitation of the target caused mixing to occur. To study this effect we made superlattice structures of alternating thin layers of Ba{sub 2}YCu{sub 3}O{sub 6+x} and BaF{sub 2}. At this point in the process some mixing has occurred, but the individual layers are still visible. However, as the bombardment continued the layers were mixed together. It may well be that one can use this phenomenon to produce high {Tc} materials with a wide range of compositions. In this report, we discuss modifications to the high {Tc} superconductors and the subsequent analysis. 10 figs.
Date: November 2, 1990
Creator: Tombrello, T.A.
Object Type: Report
System: The UNT Digital Library
On the extragalactic origin of gamma-ray bursts (open access)

On the extragalactic origin of gamma-ray bursts

A theory to explain the origin of extragalactic gamma ray bursts is presented. Collisions of black dwarf and neutron stars with a subsequent fragmentation of the dwarf producing relativistic particle accelerations toward the neutron star and a resulting turbulent flow of material at the neutron star surface is postulated. (DWL)
Date: November 2, 1984
Creator: Johnson, M. & Teller, E.
Object Type: Article
System: The UNT Digital Library