Accelerator modeling at SPEAR (open access)

Accelerator modeling at SPEAR

The response matrix, consisting of the closed orbit change at each beam position monitor (BPM) due to corrector magnet excitations, was measured and analyzed in order to calibrate a linear optics model of SPEAR. The model calibration was accomplished by varying model parameters to minimize the chi-square difference between the measured and the model response matrices. The singular value decomposition (SVD) matrix inversion method was used to solve the simultaneous equations. The calibrated model was then used to calculate corrections to the operational lattice. The results of the calibration and correction procedures are presented.
Date: May 23, 1997
Creator: LeBlanc, G. & Corbett, W.J.
Object Type: Article
System: The UNT Digital Library
Accurate atomistic simulations of the Peierls barrier and kink-pair formation energy for {lt}111{gt} screw dislocations in bcc-Mo (open access)

Accurate atomistic simulations of the Peierls barrier and kink-pair formation energy for {lt}111{gt} screw dislocations in bcc-Mo

Using multi-ion MGPT interatomic potentials derived from first- principles generalized pseudopotential theory, we have performed accurate atomistic simulations on the energetic of dislocation motion in the bcc transition metal Mo. Our calculated results include the (110) and (211) generalized stacking fault ({gamma}) energy surfaces, the Peierls stress required to move an ideal straight <111> screw dislocation, and the kink-pair formation energy for nonstraight screw dislocations. Many-body angular forces, which are accounted for in the present theory through explicit three- and four-ion potentials, are quantitatively important to such properties for the bcc transition metals. This is demonstrated explicitly through the calculated {gamma} surfaces, which are found to be 10-50% higher in energy than those obtained with pure radial-force models. The Peierls stress for an applied <111>/{l_brace}112{r_brace} shear is computed to be about 0.025{mu}, where {mu} is the bulk shear modulus. For zero applied stress, stable kink pairs are predicted to form for kink lengths greater than 4b, where b is the magnitude of the Burgers vector. For long kinks greater than 15b, the calculated asymptotic value of the kink-pair formation energy is 2.0 eV.
Date: May 23, 1997
Creator: Xu, W. & Moriarty, J.A.
Object Type: Article
System: The UNT Digital Library
Advanced ceramics for land-based gas turbine applications. Final report (open access)

Advanced ceramics for land-based gas turbine applications. Final report

In order to increase the efficiency of land-based gas turbines, inlet gas temperatures have to be increased, and the amount of air which cools the turbine vanes has to be reduced, to the maximum extent possible. Presently, thermal barrier coatings (TBC`s) are the state of the art in achieving these goals. However, since TBC`s are very thin (typically 100 {mu}m), they have clearly limitations. Since all-ceramic turbine vanes would be a very large and risky development step, Westinghouse is considering to protect the leading edges of turbine vanes with high-performance ceramics. This might be done by either replacing the leading edge with a suitably shaped ceramic part, or by modifying the vanes such that they can accommodate ceramic inserts. Among the most important criteria for the success of ceramics in such applications are (a) thermodynamic compatibility with the turbine vane alloy, (b) sufficient thermal shock resistance to survive the thermal cycling during operation and in particular during emergency shut-down, and a design considering the thermal expansion mismatch of the metallic and ceramic components. This paper presents results of work performed on SiC, SiN, and aluminas.
Date: May 23, 1997
Creator: Schneibel, J.H.; Ludeman, E. & Sabol, S.M.
Object Type: Report
System: The UNT Digital Library
FUTURE CLIMATE MODELING SCENARIOS (open access)

FUTURE CLIMATE MODELING SCENARIOS

None
Date: May 23, 1997
Creator: F.J. SCHELLING, S.L. THOMPSON
Object Type: Report
System: The UNT Digital Library
High Efficiency Vapor-Fed AMTEC System for Direct Conversion. Appendices for Final Report (open access)

High Efficiency Vapor-Fed AMTEC System for Direct Conversion. Appendices for Final Report

This report consists of four appendices for the final report. They are: Appendix A: 700 C Vapor-Fed AMTEC Cell Calculations; Appendix B: 700 C Vapor-Fed AMTEC Cell Parts Drawings; Appendix C: 800 C Vapor-Fed AMTEC Cell Calculations; and Appendix D: 800 C Wick-Pumped AMTEC Cell System Design.
Date: May 23, 1997
Creator: Anderson, W. G. & Bland, J. J.
Object Type: Report
System: The UNT Digital Library
High Efficiency Vapor-Fed AMTEC System for Direct Conversion. Final Report (open access)

High Efficiency Vapor-Fed AMTEC System for Direct Conversion. Final Report

The Alkali Metal Thermal to Electric Converter (AMTEC) is a high temperature, high efficiency system for converting thermal to electrical energy, with no moving parts. It is based on the unique properties of {beta}{double_prime}-alumina solid electrolyte (BASE), which is an excellent conductor of sodium ions, but an extremely poor conductor of electrons. When the inside of the BASE is maintained at a higher temperature and pressure, a concentration gradient is created across the BASE. Electrons and sodium atoms cannot pass through the BASE. However, the sodium atoms are ionized, and the sodium ions move through the BASE to the lower potential (temperature) region. The electrons travel externally to the AMTEC cell, providing power. There are a number of potential advantages to a wick-pumped, vapor-fed AMTEC system when compared with other designs. A wick-pumped system uses capillary forces to passively return liquid to the evaporator, and to distribute the liquid in the evaporator. Since the fluid return is self-regulating, multiple BASE tubes can use a single remote condenser, potentially improving efficiency in advanced AMTEC designs. Since the system is vapor-fed, sodium vapor is supplied at a uniform temperature and flux to the BASE tube, even with non-uniform heat fluxes and temperatures …
Date: May 23, 1997
Creator: Anderson, W. G. & Bland, J. J.
Object Type: Report
System: The UNT Digital Library
Immobilization technology down-selection radiation barrier approach (open access)

Immobilization technology down-selection radiation barrier approach

Six immobilization technology projects variants, previously selected for evaluation during the PEIS/ROD process, have been evaluated with respect to the nine basic criteria for fissile materials disposition. Metrics for the criteria were developed to facilitate a comparative analysis of the technology variants. The six technology variants are grouped according to their radiation barrier approach. Information and data for the technology options were provided by limited experimental studies, definitions of process flowsheets, and preliminary evaluations of facility concepts and costs.
Date: May 23, 1997
Creator: Gray, L.W. & Gould, T.H.
Object Type: Report
System: The UNT Digital Library
Magnetometer calibration and test procedure (open access)

Magnetometer calibration and test procedure

Nuclear waste has been sluiced and pumped from storage tank 241-AX-104, leaving a contaminated heel volume. These operations did not include measurements of the removed waste volume leaving an unknown heel volume in the tank. A magnetometer transducer will be lowered through tank riser ports to rest on the heel`s surface. The heel thickness will control the distance between the transducer and the tank`s bottom The instrument`s output varies with the distance from a magnetic mass, such as the tank`s steel bottom, thereby enabling a measurement of the heel depth. Measurements at several tank locations will permit an estimate of the tank`s heel volume. The magnetometer`s output is influenced by adjacent magnetic materials, such as the tank walls, air lift circulators or other equipment installed in the tank. An adjacent vertical steel surface produces a voltage offset in the instrument`s output. Measurements near a tank wall or other tank components may be corrected by noting the offset before the instrument`s output is influenced by the tank bottom. An unlevel or uneven heel surface could orient the magnetometer transducer so that it is not vertically level. The magnetometer readings are influenced by these skewed transducer orientations. The magnitude of these errors …
Date: May 23, 1997
Creator: Squier, D. M.
Object Type: Report
System: The UNT Digital Library
Quantum groups, roots of unity and particles on quantized Anti-de Sitter space (open access)

Quantum groups, roots of unity and particles on quantized Anti-de Sitter space

Quantum groups in general and the quantum Anti-de Sitter group U{sub q}(so(2,3)) in particular are studied from the point of view of quantum field theory. The author shows that if q is a suitable root of unity, there exist finite-dimensional, unitary representations corresponding to essentially all the classical one-particle representations with (half) integer spin, with the same structure at low energies as in the classical case. In the massless case for spin {ge} 1, {open_quotes}naive{close_quotes} representations are unitarizable only after factoring out a subspace of {open_quotes}pure gauges{close_quotes}, as classically. Unitary many-particle representations are defined, with the correct classical limit. Furthermore, the author identifies a remarkable element Q in the center of U{sub q}(g), which plays the role of a BRST operator in the case of U{sub q}(so(2,3)) at roots of unity, for any spin {ge} 1. The associated ghosts are an intrinsic part of the indecomposable representations. The author shows how to define an involution on algebras of creation and anihilation operators at roots of unity, in an example corresponding to non-identical particles. It is shown how nonabelian gauge fields appear naturally in this framework, without having to define connections on fiber bundles. Integration on Quantum Euclidean space and sphere …
Date: May 23, 1997
Creator: Steinacker, H.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Russia’s Nuclear Forces: Doctrine and Force Structure Issues (open access)

Russia’s Nuclear Forces: Doctrine and Force Structure Issues

None
Date: May 23, 1997
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Strategy for resolution of the flammable gas safety issue (open access)

Strategy for resolution of the flammable gas safety issue

This document provides a strategy for resolution of the Flammable Gas Safety Issue. It defines the key elements required for the following: Closing the Flammable Gas Unreviewed Safety Question (USQ); Providing the administrative basis for resolving the safety issue; Defining the data needed to support these activities; and Providing the technical and administrative path for removing tanks from the Watch List.
Date: May 23, 1997
Creator: Johnson, G. D.
Object Type: Report
System: The UNT Digital Library
Tank characterization report for single-shell tank 241-C-109 (open access)

Tank characterization report for single-shell tank 241-C-109

One of the major functions of the Tank Waste Remediation System (TWRS) is to characterize wastes in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis, along with other available information about a tank, are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-C-109. The objectives of this report are: (1) to use characterization data in response to technical issues associated with tank 241 C-109 waste; and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. The response to technical issues is summarized in Section 2.0, and the best-basis inventory estimate is presented in Section 3.0. Recommendations regarding safety status and additional sampling needs are provided in Section 4.0. Supporting data and information are contained in the appendices.
Date: May 23, 1997
Creator: Simpson, B. C.
Object Type: Report
System: The UNT Digital Library
Texas Register, Volume 22, Number 39, Pages 4399-4554, May 23, 1997 (open access)

Texas Register, Volume 22, Number 39, Pages 4399-4554, May 23, 1997

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.
Date: May 23, 1997
Creator: Texas. Secretary of State.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Tobacco Advertising: Whether the FDA's Restrictions Violate Freedom of Speech (open access)

Tobacco Advertising: Whether the FDA's Restrictions Violate Freedom of Speech

This report considers whether the provisions of the FDA's final rule restricting the advertising of cigarettes and smokeless tobacco products violates the First Amendment's guarantee of freedom of speech.
Date: May 23, 1997
Creator: Cohen, Henry
Object Type: Report
System: The UNT Digital Library
Tobacco Advertising: Whether the FDA's Restrictions Violate Freedom of Speech (open access)

Tobacco Advertising: Whether the FDA's Restrictions Violate Freedom of Speech

None
Date: May 23, 1997
Creator: Cohen, Henry
Object Type: Report
System: The UNT Digital Library
Tomographic Site Characterization Using CPT, ERT, and GPR (open access)

Tomographic Site Characterization Using CPT, ERT, and GPR

The U.S. Department of Energy (DOE) is responsible for the cleanup of inactive DOE sites and for bringing DOE sites and facilities into compliance with federal, state and local laws and regulations. The DOE's Office of Environmental Management (EM) needs advanced technologies that can make environmental restoration and waste management operations more efficient and less costly. These techniques are required to better characterize the physical, hydrogeological, and chemical properties of the subsurface while minimizing and optimizing the use of boreholes and monitoring wells. Today the cone penetrometer technique (CPT) is demonstrating the value of a minimally invasive deployment system fix site characterization. Applied Research Associates is developing two new sensor packages for site characterization and monitoring. The two new methods are: . Electrical Resistivity Tomography (ERT) and . Ground Penetrating Radar (GPR) Tomography. These sensor systems are now integrated with the Cone Penetrometer Technique (CPT). The results of this program now make it possible to install ERT and GPR units by CPT methods and thereby reduce installation costs and total costs for ERT and GPR surveys. These two techniques can complement each other in regions of low resistivity where ERT is more effective and regions of high resistivity where GPR …
Date: May 23, 1997
Creator: Morey, Rexford M.
Object Type: Report
System: The UNT Digital Library