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Material dynamics at extreme pressures and strain rates (open access)

Material dynamics at extreme pressures and strain rates

Solid state experiments at extreme pressures (10-100 GPa) and strain rates ({approx}10{sup 6}-10{sup 8}s{sup -1}) are being developed on high-energy laser facilities, and offer the possibility for exploring new regimes of materials science. [Re 2004] These extreme solid-state conditions can be accessed with either shock loading or with quasi-isentropic ramped pressure pulses being developed on the Omega laser. [Ed 2004] Velocity interferometer measurements establish the high strain rates. Constitutive models for solid-state strength under these conditions are tested by comparing 2D continuum simulations with experiments measuring perturbation growth due to the Rayleigh-Taylor instability in solid-state samples. Lattice compression, phase, and temperature are deduced from extended x-ray absorption fine structure (EXAFS) measurements, from which the shock-induced a-w phase transition in Ti is inferred to occur on sub-nanosecond time scales. [Ya 2004] Time resolved lattice response and phase can be inferred from dynamic x-ray diffraction measurements, where the elastic-plastic (1D-3D) lattice relaxation in shocked Cu is shown to occur promptly (< 1 ns). [Lo 2003] Subsequent large-scale MD simulations have elucidated the microscopic dynamics that underlie the 3D lattice relaxation. Deformation mechanisms are identified by examining the residual microstructure in recovered samples. [Re 2004] For example, the slip-twinning threshold in single-crystal Cu …
Date: August 25, 2004
Creator: Remington, Bruce A.; Cavallo, Rob M.; Edwards, Michael J.; Ho, David D.; Lasinski, Barbara F.; Lorenz, Karl T. et al.
Object Type: Article
System: The UNT Digital Library
Cherokeean Herald (Rusk, Tex.), Vol. 155, No. 27, Ed. 1 Wednesday, August 25, 2004 (open access)

Cherokeean Herald (Rusk, Tex.), Vol. 155, No. 27, Ed. 1 Wednesday, August 25, 2004

Weekly newspaper from Rusk, Texas that includes local, state and national news along with extensive advertising.
Date: August 25, 2004
Creator: Whitehead, Marie
Object Type: Newspaper
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0237 (open access)

Texas Attorney General Opinion: GA-0237

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Whether the liens for public improvement district assessments levied against property that was not a homestead at the time of assessment may be enforced by foreclosure even though the property has become a homestead between the date of assessment and the date of the enforcement action (RQ-0187-GA)
Date: August 25, 2004
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0238 (open access)

Texas Attorney General Opinion: GA-0238

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Whether deputy sheriffs are "police officers" for purposes of Local Government Code chapter 174, The Fire and Police Employee Relations Act (RQ-0189-GA)
Date: August 25, 2004
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0239 (open access)

Texas Attorney General Opinion: GA-0239

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Whether the Board of the Professionals Land Surveying may establish a "retired status" catergory for its registrants, set a reduced renewal fee, and waive continuing education requirements for those individuals (RQ-0191-GA)
Date: August 25, 2004
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0240 (open access)

Texas Attorney General Opinion: GA-0240

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Authority of the Board of Pardons and Paroles to consider applications for pardons and based on innocence (RQ-0192-GA)
Date: August 25, 2004
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Fabrication of a Carbon Nanotube-Embedded Silicon Nitride Membrane for Studies of Nanometer-Scale Mass Transport (open access)

Fabrication of a Carbon Nanotube-Embedded Silicon Nitride Membrane for Studies of Nanometer-Scale Mass Transport

A membrane consisting of multiwall carbon nanotubes embedded in a silicon nitride matrix was fabricated for fluid mechanics studies on the nanometer scale. Characterization by tracer diffusion and scanning electron microscopy suggests that the membrane is free of large voids. An upper limit to the diffusive flux of D{sub 2}O of 2.4x10-{sup 8} mole/m{sup 2}-s was determined, indicating extremely slow transport. By contrast, hydrodynamic calculations of water flow across a nanotube membrane of similar specifications predict a much higher molar flux of 1.91 mole/m{sup 2}-s, suggesting that the nanotubes produced possess a 'bamboo' morphology. The carbon nanotube membranes were used to make nanoporous silicon nitride membranes, fabricated by sacrificial removal of the carbon. Nitrogen flow measurements on these structures give a membrane permeance of 4.7x10{sup -4} mole/m{sup 2}-s-Pa at a pore density of 4x10{sup 10} cm{sup -2}. Using a Knudsen diffusion model, the average pore size of this membrane is estimated to be 66 nm, which agrees well with TEM observations of the multiwall carbon nanotube outer diameter. These membranes are a robust platform for the study of confined molecular transport, with applications inseparations and chemical sensing.
Date: August 25, 2004
Creator: Holt, J K; Noy, A; Huser, T; Eaglesham, D & Bakajin, O
Object Type: Article
System: The UNT Digital Library
Harmonic cascade FEL designs for LUX, a facility for ultrafast x-ray science (open access)

Harmonic cascade FEL designs for LUX, a facility for ultrafast x-ray science

LUX is a design study to develop concepts for future ultrafast x-ray facilities. Presently, LUX is based on an electron beam accelerated to {approx}3-GeV energy in a superconducting, recirculating linac. Included in the design are multiple free-electron laser (FEL) beamlines which use the harmonic cascade approach to produce coherent XUV and soft X-ray emission beginning with a strong input seed at {approx}200-nm wavelength obtained from a ''conventional'' laser. Each cascade module generally operates in the low-gain regime and is composed of a radiator together with a modulator section, separated by a magnetic chicane. The chicane temporally delays the electron beam pulse in order that a ''virgin'' pulse region (with undegraded energy spread) be brought into synchronism with the radiation pulse. For a given cascade, the output photon energy can be selected over a wide range by varying the seed laser wavelength and the field strength in the undulators. We present numerical simulation results, as well as those from analytical models, to examine certain aspects of the predicted FEL performance. We also discuss lattice considerations pertinent to harmonic cascade FELs, some sensitivity studies and requirements on the undulator alignment, and temporal pulse evolution initiated by short input radiation seeds.
Date: August 25, 2004
Creator: Corlett, John; Fawley, William; Penn, Gregory; Wan, Weishi; Zholents, A.; Reinsch, M. et al.
Object Type: Article
System: The UNT Digital Library
Hybrid 320 Ton Off Highway Haul Truck: Quarterly Technical Status Report 7, DOE/AL68080-TSR07 (open access)

Hybrid 320 Ton Off Highway Haul Truck: Quarterly Technical Status Report 7, DOE/AL68080-TSR07

Analysis and results show hybrid system weight and efficiency affect productivity and fuel usage. Analysis shows equivalent hybrid benefits for adjacent size classes of mine truck. Preparations are ongoing for full power test. The battery cycling test protocol was modified.
Date: August 25, 2004
Creator: Salasoo, Lembit
Object Type: Report
System: The UNT Digital Library
44-BWR WASTE PACKAGE LOADING CURVE EVALUATION (open access)

44-BWR WASTE PACKAGE LOADING CURVE EVALUATION

The objective of this calculation is to evaluate the required minimum burnup as a function of initial boiling water reactor (BWR) assembly enrichment that would permit loading of spent nuclear fuel into the 44 BWR waste package configuration as provided in Attachment IV. This calculation is an application of the methodology presented in ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). The scope of this calculation covers a range of enrichments from 0 through 5.0 weight percent (wt%) U-235, and a burnup range of 0 through 40 GWd/MTU. This activity supports the validation of the use of burnup credit for commercial spent nuclear fuel applications. The intended use of these results will be in establishing BWR waste package configuration loading specifications. Limitations of this evaluation are as follows: (1) The results are based on burnup credit for actinides and selected fission products as proposed in YMP (2003, Table 3-1) and referred to as the ''Principal Isotopes''. Any change to the isotope listing will have a direct impact on the results of this report. (2) The results of 100 percent of the current BWR projected waste stream being able to be disposed of in the 44-BWR waste package with Ni-Gd Alloy …
Date: August 25, 2004
Creator: Scaglione, J.M.
Object Type: Report
System: The UNT Digital Library

Oral History Interview with Norman Mailer, August 25, 2004

Access: Use of this item is restricted to the UNT Community
Interview with Norman Mailer, novelist and Army veteran. The interview includes Mailer's personal experiences about World War II in the Philippines, Army life, jungle patrols, and the Japanese surrender in Tokyo Bay. Mailer talks about the role of his wartime experiences in his novel, The Naked and the Dead.
Date: August 25, 2004
Creator: Johnston, Glenn T. & Mailer, Norman
Object Type: Book
System: The UNT Digital Library
The Archer Advocate (Holliday, Tex.), Vol. 2, No. 21, Ed. 1 Wednesday, August 25, 2004 (open access)

The Archer Advocate (Holliday, Tex.), Vol. 2, No. 21, Ed. 1 Wednesday, August 25, 2004

Weekly newspaper from Holliday, Texas that includes local, state, and national news along with advertising.
Date: August 25, 2004
Creator: Thomas, John
Object Type: Newspaper
System: The Portal to Texas History
The Baytown Sun (Baytown, Tex.), Vol. 83, No. 268, Ed. 1 Wednesday, August 25, 2004 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 83, No. 268, Ed. 1 Wednesday, August 25, 2004

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: August 25, 2004
Creator: Cash, Wanda Garner
Object Type: Newspaper
System: The Portal to Texas History
The Cuero Record (Cuero, Tex.), Vol. 110, No. 34, Ed. 1 Wednesday, August 25, 2004 (open access)

The Cuero Record (Cuero, Tex.), Vol. 110, No. 34, Ed. 1 Wednesday, August 25, 2004

Weekly newspaper from Cuero, Texas that includes local, state, and national news along with advertising.
Date: August 25, 2004
Creator: Rea, Glenn
Object Type: Newspaper
System: The Portal to Texas History
Bounds and Estimates for Elastic Constants of Random Polycrystals of Laminates (open access)

Bounds and Estimates for Elastic Constants of Random Polycrystals of Laminates

In order to obtain formulas providing estimates for elastic constants of random polycrystals of laminates, some known rigorous bounds of Peselnick, Meister, and Watt are first simplified. Then, some new self-consistent estimates are formulated based on the resulting analytical structure of these bounds. A numerical study is made, assuming first that the internal structure (i.e., the laminated grain structure) is not known, and then that it is known. The purpose of this aspect of the study is to attempt to quantify the differences in the predictions of properties of the same system being modeled when such internal structure of the composite medium and spatial correlation information is and is not available.
Date: August 25, 2004
Creator: Berger, E. L.
Object Type: Article
System: The UNT Digital Library
Large-Actuator-Number Horizontal Path Correction of Atmospheric Turbulence utilizing an Interferometric Phase Conjugate Engine (open access)

Large-Actuator-Number Horizontal Path Correction of Atmospheric Turbulence utilizing an Interferometric Phase Conjugate Engine

An adaptive optical system used to correct horizontal beam propagation paths has been demonstrated. This system utilizes an interferometric wave-front sensor and a large-actuator-number MEMS-based spatial light modulator to correct the aberrations incurred by the beam after propagation along the path. Horizontal path correction presents a severe challenge to adaptive optics systems due to the short atmospheric transverse coherence length and the high degree of scintillation incurred by laser propagation along these paths. Unlike wave-front sensors that detect phase gradients, however, the interferometric wave-front sensor measures the wrapped phase directly. Because the system operates with nearly monochromatic light and uses a segmented spatial light modulator, it does not require that the phase be unwrapped to provide a correction and it also does not require a global reconstruction of the wave-front to determine the phase as required by gradient detecting wave-front sensors. As a result, issues with branch points are eliminated. Because the atmospheric probe beam is mixed with a large amplitude reference beam, it can be made to operate in a photon noise limited regime making its performance relatively unaffected by scintillation. The MEMS-based spatial light modulator in the system contains 1024 pixels and is controlled to speeds in excess …
Date: August 25, 2004
Creator: Baker, K. L.; Stappaerts, E. A.; Gavel, D.; Tucker, J.; Silva, D. A.; Wilks, S. C. et al.
Object Type: Article
System: The UNT Digital Library
Excitation Cross Section Measurement for n=3 to n=2 Line Emission in Fe{sup 20+} to Fe{sup 23+} (open access)

Excitation Cross Section Measurement for n=3 to n=2 Line Emission in Fe{sup 20+} to Fe{sup 23+}

Electron impact excitation cross sections have been measured for iron L-shell 3 {yields} 2 lines of FeXXI to FeXXIV at the EBIT-II electron beam ion trap using a crystal spectrometer and a 6 x 6-element array microcalorimeter. The cross sections were determined by direct normalization to the well established cross section of radiative electron capture and a summary of calculated energy dependent radiative recombination cross sections for electron capture into the ground state fine structure levels of Fe{sup 16+} to Fe{sup 23+} ions is given. The measurement results for 17 lines and their comparison with model calculations are presented. While agreement of the model calculations with experiment is good for most measured lines, significant discrepancies were found for a few lines, including the strongest line in Fe XXI.
Date: August 25, 2004
Creator: Chen, H; Beiersdorfer, P; Scofield, J; Brown, G; Boyce, K; Kelley, R L et al.
Object Type: Article
System: The UNT Digital Library
The Colony Courier-Leader (The Colony, Tex.), Vol. 23, No. 29, Ed. 1 Wednesday, August 25, 2004 (open access)

The Colony Courier-Leader (The Colony, Tex.), Vol. 23, No. 29, Ed. 1 Wednesday, August 25, 2004

Weekly newspaper from The Colony, Texas that includes local, state, and national news along with advertising.
Date: August 25, 2004
Creator: Sorter, Dave
Object Type: Newspaper
System: The Portal to Texas History
Deposit Summary (open access)

Deposit Summary

Deposit summary with a total of $20.00 on August 23, 2004.
Date: August 25, 2004
Creator: unknown
Object Type: Text
System: The UNT Digital Library
[News Clip: Church Bus Trial] captions transcript

[News Clip: Church Bus Trial]

Video footage from the NBC 5 television station in Fort Worth, Texas, to accompany a news story. This story aired at 6 P.M.
Date: August 25, 2004
Creator: KXAS-TV (Television station : Fort Worth, Tex.)
Object Type: Video
System: The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 106, No. 125, Ed. 1 Wednesday, August 25, 2004 (open access)

Altus Times (Altus, Okla.), Vol. 106, No. 125, Ed. 1 Wednesday, August 25, 2004

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: August 25, 2004
Creator: Andrews, Mike
Object Type: Newspaper
System: The Gateway to Oklahoma History
Current-enhanced SASE using an optical laser and its applicationto the LCLS (open access)

Current-enhanced SASE using an optical laser and its applicationto the LCLS

We propose a significant enhancement of the electron peak current entering a SASE undulator by inducing an energy modulation in an upstream wiggler magnet via resonant interaction with an optical laser, followed by microbunching of the energy-modulated electrons at the accelerator exit. This current enhancement allows a reduction of the FEL gain length. The x-ray output consists of a series of uniformly spaced spikes, each spike being temporally coherent. The duration of this series is controlled by the laser pulse and in principle can be narrowed down to just a single, 200-attosecond spike. Given potentially absolute temporal synchronization of the x-ray spikes to the energy-modulating laser pulse, this scheme naturally makes pump-probe experiments available to SASE FEL's. We also study various detrimental effects related to the high electron peak current.
Date: August 25, 2004
Creator: Zholents, Alexander A.; Fawley, William M.; Emma, Paul; Huang,Zhirong; Reiche, Sven & Stupakov, Gennady
Object Type: Article
System: The UNT Digital Library
The Optimist (Abilene, Tex.), Vol. 93, No. 2, Ed. 1, Wednesday, August 25, 2004 (open access)

The Optimist (Abilene, Tex.), Vol. 93, No. 2, Ed. 1, Wednesday, August 25, 2004

Tri-weekly student newspaper from Abilene Christian University in Abilene, Texas that includes local, state and campus news along with advertising.
Date: August 25, 2004
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 89, No. 294, Ed. 1 Wednesday, August 25, 2004 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 89, No. 294, Ed. 1 Wednesday, August 25, 2004

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: August 25, 2004
Creator: Broaddus, Matthew B.
Object Type: Newspaper
System: The Gateway to Oklahoma History