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Superfluid Performance of Tevatron IR Quad Heaters (open access)

Superfluid Performance of Tevatron IR Quad Heaters

A collaborative team from the two laboratories measured the performance of a Tevatron Interaction region (IR) quadrupole at temperatures from 1.8 K to 4.4 K. These studies included measurement of their performance as a function of temperature as well as measurement of the effectiveness of the protection heaters. Heater diffusion times were measured for various temperatures, current levels, and power densities. These results and their implications on the design of magnet protection systems and magnet design operating in this temperature range will be discussed.
Date: December 12, 1996
Creator: Lietzke, A.; McInturff, A. D. & Scanlan, R. M.
System: The UNT Digital Library
Wakimoto realizations of current algebras: an explicit construction (open access)

Wakimoto realizations of current algebras: an explicit construction

A generalized Wakimoto realization of $\widehat\cal G_K$ can be associated with each parabolic subalgebra $\cal P=(\cal G_0 +\cal G_+)$ of a simple Lie algebra $\cal G$ according to an earlier proposal by Feigin and Frenkel. In this paper the proposal is made explicit by developing the construction of Wakimoto realizations from a simple but unconventional viewpoint. An explicit formula is derived for the Wakimoto current first at the Poisson bracket level by Hamiltonian symmetry reduction of the WZNW model. The quantization is then performed by normal ordering the classical formula and determining the required quantum correction for it to generate $\widehat\cal G_K$ by means of commutators. The affine-Sugawara stress-energy tensor is verified to have the expected quadratic form in the constituents, which are symplectic bosons belonging to $\cal G_+$ and a current belonging to $\cal G_0$. The quantization requires a choice of special polynomial coordinates on the big cell of the flag manifold $P\backslash G$. The effect of this choice is investigated in detail by constructing quantum coordinate transformations. Finally, the explicit form of the screening charges for each generalized Wakimoto realization is determined, and some applications are briefly discussed.
Date: November 12, 1996
Creator: de Boer, Jan & Feher, Laszlo
System: The UNT Digital Library
The Pipe-Quadrupole, an Alternative for High Gradient Interaction Region Quadrupole Designs (open access)

The Pipe-Quadrupole, an Alternative for High Gradient Interaction Region Quadrupole Designs

In the design of interaction region (IR) quadrupoles for high luminosity colliders such as the LHC or a possible upgrade of the Tevatron, the radiation heating of the coil windings is an important issue. Two obvious solutions to this problem can be chosen. The first is to reduce the heat load by added shielding, increased cooling with fins or using Nb{sub 3}Sn to increase the temperature margin. The second solution eliminates the conductor from the areas with the highest radiation intensity, which are located on the symmetry-axes of the midplanes of the coils. A novel quadrupole design is presented, in which the conductor is wound on four half-moon shaped supports, forming elongated toroid sections. The assembly of the four shapes yields a quadrupole field with an active flux return path, and a void in the high radiation area. This void can be occupied by a liquid helium cooling pipe to lower the temperature of the windings from the inside. The coil layout, harmonic optimization and mechanical design are shown, together with the calculated temperature rise for the radiation load of the LHC interaction region quadrupoles.
Date: December 12, 1996
Creator: van Oort, J. M. & Scanlan, R. M.
System: The UNT Digital Library
Design and Fabrication of a High Aspect Ratio Cable for a High Gradie nt Quadrupole Magnet (open access)

Design and Fabrication of a High Aspect Ratio Cable for a High Gradie nt Quadrupole Magnet

The Large Hadron Collider interaction regions require quadrupoles with a 70 mm diameter bore, a gradient of 250 T/m, and good cooling so that the magnets can operate in a high radiation background without quenching. In order to meet these stringent requirements, a two-layer magnet with a high aspect ratio cable has been designed. This cable ulilizes the SSC inner and outer layer strands, which have been optimized and are available in large quantities. The initial design parameters for both cables are 15.2 mm width; the inner cable has 38 strands of 0.8 mm diam wire and a keystone angle of 0.99 deg. The outer cable has 46 strands of 0.65 mm diam wire and a keystone angle of 0.69 deg. These cables have been fabricated and then subjected to a number of tests to insure their performance in the quadrupole. These test results, including model coil winding studies, electrical property measurements, and mechanical property measurements will be presented.
Date: December 12, 1996
Creator: Scanlan, R. M.; McInturff, A. D.; Taylor, C. E.; Caspi, S.; Dell'Orco, D.; Higley, H. et al.
System: The UNT Digital Library
Test Results on Nb3Sn Dipole Magnets (open access)

Test Results on Nb3Sn Dipole Magnets

A cosine theta type dipole magnet using Nb{sub 3}Sn conductor have been designed, built and tested. D19H is a two-layer dipole magnet with a Nb{sub 3}Sn inner layer and a NbTi outer layer. Coil-pairs are connected with two of the four Nb{sub 3}Sn splices in a high field region, and compressed by a ring and collet system. It trained well at 4.4K, but poorly at 1.8K. Strain gages revealed that the coil-ends were not loaded well enough for high field operation (after cool-down), so another thermal cycle is planned. The low end-load is believed to be the cause of several mysteries observed during operation. Except for the outer-layer 1.8 K training difficulty, the magnet's operation was encouraging.
Date: December 12, 1996
Creator: Lietzke, A. F.; Benjegerdes, R.; Caspi, S.; Dell'Orco, D.; Harnden, W.; McInturff, A. D. et al.
System: The UNT Digital Library
Nb3Sn Artificial Pinning Microstructures (open access)

Nb3Sn Artificial Pinning Microstructures

Extension of the APC approach to Nb{sub 3}Sn requires that a second phae be incorporated into the Nb{sub 3}Sn layer. The second phase would increase pinning strength by either reducing the grain size or by the second phase pinning the flux itwelf. The following criteria for elements to be candidates for the APC approach are: (1) they must form intermetallic compounds with Cu or Sn and (2) they must have negligible solubility in Cu and Nb or they must be strong oxide formers. many of the rare earth elements satisfy these criteria. To circumvent the large strains required to produce wires with a fine distribution of the second phase, film deposition techniques have been used. Critical current densities for Nb films doped with Ti and Y are about 4,000 A/mm{sup 2} at 6T and 4.2 K.
Date: December 12, 1996
Creator: Dietderich, D. R. & Scanlan, R. M.
System: The UNT Digital Library
Solubility of Anthracene in Binary Alcohol + 2-Pentanol and Alcohol + 4-Methyl-2-pentanol Solvent Mixtures (open access)

Solubility of Anthracene in Binary Alcohol + 2-Pentanol and Alcohol + 4-Methyl-2-pentanol Solvent Mixtures

Article on the solubility of anthracene in binary alcohol + 2-pentanol and alcohol + 4-methyl-2-pentanol solvent mixtures.
Date: July 12, 1996
Creator: Powell, Joyce R.; McHale, Mary E. R.; Kauppila, Ann-Sofi M. & Acree, William E. (William Eugene)
System: The UNT Digital Library
Solubility of Pyrene in Binary Alcohol + Cyclohexanol and Alcohol + 1-Pentanol Solvent Mixtures at 299.2 K (open access)

Solubility of Pyrene in Binary Alcohol + Cyclohexanol and Alcohol + 1-Pentanol Solvent Mixtures at 299.2 K

Article on the solubility of pyrene in binary alcohol + cyclohexanol and alcohol + 1-pentanol solvent mixtures at 299.2 K.
Date: November 12, 1996
Creator: McHale, Mary E. R.; Horton, Ann-Sofi M.; Padilla, Sandra A.; Trufant, Ashantè L.; De La Sancha, Noé U.; Vela, Ernesto et al.
System: The UNT Digital Library
Solubility of Benzil in Binary Alkane + Methyl tert-Butyl Ether Solvent Mixtures (open access)

Solubility of Benzil in Binary Alkane + Methyl tert-Butyl Ether Solvent Mixtures

Article on the solubility of benzil in binary alkane + methyl tert-butyl ether solvent mixtures.
Date: September 12, 1996
Creator: McHale, Mary E. R.; Powell, Joyce R.; Kauppila, Ann-Sofi M. & Acree, William E. (William Eugene)
System: The UNT Digital Library
Solubility of Anthracene in Binary Alkane + Methyl tert-Butyl Ether Solvent Mixtures at 298.15 K (open access)

Solubility of Anthracene in Binary Alkane + Methyl tert-Butyl Ether Solvent Mixtures at 298.15 K

Article on the solubility of anthracene in binary alkane + methyl tert-butyl ether solvent mixtures at 298.15 K.
Date: September 12, 1996
Creator: McHale, Mary E. R.; Kauppila, Ann-Sofi M. & Acree, William E. (William Eugene)
System: The UNT Digital Library
Solubility of Anthracene in Binary Alcohol + 2-Propoxyethanol Solvent Mixtures (open access)

Solubility of Anthracene in Binary Alcohol + 2-Propoxyethanol Solvent Mixtures

Article on the solubility of anthracene in binary alcohol + 2-propoxyethanol solvent mixtures.
Date: March 12, 1996
Creator: McHale, Mary E. R.; Powell, Joyce R.; Kauppila, Ann-Sofi M. & Acree, William E. (William Eugene)
System: The UNT Digital Library
Linear Response of Hamiltonian Chaotic Systems as a Function of the Number of Degrees of Freedom (open access)

Linear Response of Hamiltonian Chaotic Systems as a Function of the Number of Degrees of Freedom

This article discusses the linear response of Hamiltonian chaotic systems as a function of the number of degrees of freedom.
Date: August 12, 1996
Creator: Bianucci, Marco; Mannella, Riccardo & Grigolini, Paolo
System: The UNT Digital Library
Career toolbox - the decision paper: A tool to facilitate decision-making (open access)

Career toolbox - the decision paper: A tool to facilitate decision-making

Guidelines for writing a decision paper are presented. The purpose of the decision paper is to present complex issues in an organized format; it is especially helpful when timeliness is important. The writing style and format of the decision paper are described. The format for a decision paper includes the issue or problem statement, relevant background material, options or alternatives, discussion, recommendation, coordination/endorsement, and record of decision.
Date: November 12, 1996
Creator: Williams, J.L. & Petersen, T.P.
System: The UNT Digital Library
Large-eddy simulation in complex domains using the finite element method (open access)

Large-eddy simulation in complex domains using the finite element method

Finite element methods (FEM) are demonstrated in combination with large-eddy simulations (LES) as a valuable tool for the study of turbulent, separating channel flows, specifically the flow over a backward facing step.
Date: November 12, 1996
Creator: McCallen, R.C.; Kornblum, B.T. & Kollman, W.
System: The UNT Digital Library
Quantitative high resolution electron microscopy of grain boundaries (open access)

Quantitative high resolution electron microscopy of grain boundaries

The {Sigma}11 (113)/[1{bar 1}0] symmetric tilt grain boundary has been characterized by high resolution transmission electron microscopy. The method by which the images are prepared for analysis is described. The statistics of the image data have been found to follow a normal distribution. The electron-optical imaging parameters used to acquire the image have been determined by nonlinear least-square image simulation optimization within the perfect crystal region of the micrograph. A similar image simulation optimization procedure is used to determine the atom positions which provide the best match between the experimental image and the image simulation.
Date: December 12, 1996
Creator: Campbell, G.H., King, W.E., Cohen, D., Carter, C.B.
System: The UNT Digital Library
Development and Evaluation of First Wall Materials for the National Ignition Facility (open access)

Development and Evaluation of First Wall Materials for the National Ignition Facility

Several low-Z refractory materials are evaluated for use as the NIF first wall in terms of their cost and ability to survive laser light, target emissions and debris, as well as be cleanable and not outgas excessively. Best performers contain B, C, or both, with B{sub 4}C being the best overall. It appears possible at this time that plasma-sprayed B{sub 4}C can be fabricated with low enough porosity and cost to be preferred to hot-pressed B{sub 4}C, the conservative choice.
Date: June 12, 1996
Creator: Burnham, A. K.; Tobin, M. T.; Anderson, A. T.; Honea, E. C.; Skulina, K. M.; Milam, D. et al.
System: The UNT Digital Library
NIF: Impacts of chemical accidents and comparison of chemical/radiological accident approaches (open access)

NIF: Impacts of chemical accidents and comparison of chemical/radiological accident approaches

The US Department of Energy (DOE) proposes to construct and operate the National Ignition Facility (NIF). The goals of the NIF are to (1) achieve fusion ignition in the laboratory for the first time by using inertial confinement fusion (ICF) technology based on an advanced-design neodymium glass solid-state laser, and (2) conduct high-energy-density experiments in support of national security and civilian applications. The primary focus of this paper is worker-public health and safety issues associated with postulated chemical accidents during the operation of NIF. The key findings from the accident analysis will be presented. Although NIF chemical accidents will be emphasized, the important differences between chemical and radiological accident analysis approaches and the metrics for reporting results will be highlighted. These differences are common EIS facility and transportation accident assessments.
Date: January 12, 1996
Creator: Lazaro, M. A.; Policastro, A. J. & Rhodes, M.
System: The UNT Digital Library
Geostatistics and cost-effective environmental remediation (open access)

Geostatistics and cost-effective environmental remediation

Numerous sites within the U.S. Department of Energy (DOE) complex have been contaminated with various radioactive and hazardous materials by defense-related activities during the post-World War II era. The perception is that characterization and remediation of these contaminated sites will be too costly using currently available technology. Consequently, the DOE Office of Technology Development has funded development of a number of alternative processes for characterizing and remediating these sites. The former Feed-Materials Processing Center near Fernald, Ohio (USA), was selected for demonstrating several innovative technologies. Contamination at the Fernald site consists principally of particulate uranium and derivative compounds in surficial soil. A field-characterization demonstration program was conducted during the summer of 1994 specifically to demonstrate the relative economic performance of seven proposed advanced-characterization tools for measuring uranium activity of in-situ soils. These innovative measurement technologies are principally radiation detectors of varied designs. Four industry-standard measurement technologies, including conventional, regulatory-agency-accepted soil sampling followed by laboratory geochemical analysis, were also demonstrated during the program for comparative purposes. A risk-based economic-decision model has been used to evaluate the performance of these alternative characterization tools. The decision model computes the dollar value of an objective function for each of the different characterization approaches. The …
Date: April 12, 1996
Creator: Rautman, C.A.
System: The UNT Digital Library
The development of a monitoring system for use in Iraq (open access)

The development of a monitoring system for use in Iraq

In April 1993, the United Nations Special Commission (UNSCOM), through the U.S. Department of State, requested hardware to monitor two rocket motor test stands in Iraq. The Department of Energy`s Lawrence Livermore National Laboratory responded with project Dustcloud. Within two weeks of the request, LLNL delivered two video monitoring systems which were deployed to Iraq and installed at the Al Azim solid motor test site and the Al Rafah liquid engine test site, each about 75 km from Baghdad. The original request included a set of loosely defined requirements to perform remote monitoring in accordance with applicable United Nations Resolutions. The Sheraton Hotel in Baghdad was to be the site of the central monitoring station. While these first systems satisfied the original requirements, they were technically cumbersome and did not lend themselves to easy expansion, or mass production. A request for a second phase design was received in May 1994. The second phase design provided a more general solution to the monitoring requirement and extended the number of monitored facilities to a total of 25 and provided a continuous monitoring capability at a mutually agreed upon site located outside of the monitored country. The Phase II hardware was placed in …
Date: August 12, 1996
Creator: Fuess, D.A.
System: The UNT Digital Library
Management of data quality of high level waste characterization (open access)

Management of data quality of high level waste characterization

Over the past 10 years, the Hanford Site has been transitioning from nuclear materials production to Site cleanup operations. High-level waste characterization at the Hanford Site provides data to support present waste processing operations, tank safety programs, and future waste disposal programs. Quality elements in the high-level waste characterization program will be presented by following a sample through the data quality objective, sampling, laboratory analysis and data review process. Transition from production to cleanup has resulted in changes in quality systems and program; the changes, as well as other issues in these quality programs, will be described. Laboratory assessment through quality control and performance evaluation programs will be described, and data assessments in the laboratory and final reporting in the tank characterization reports will be discussed.
Date: June 12, 1996
Creator: Winters, W. I.
System: The UNT Digital Library
Progress toward a performance based specification for diamond grinding wheels (open access)

Progress toward a performance based specification for diamond grinding wheels

This work sought to improve the communication between users and makers of fine diamond grinding wheels. A promising avenue for this is to formulate a voluntary product standard that comprises performance indicators that bridge the gap between specific user requirements and the details of wheel formulations. We propose a set of performance specifiers of figures-of-merit, that might be assessed by straightforward and traceable testing methods, but do not compromise proprietary information of the wheel user of wheel maker. One such performance indicator might be wheel hardness. In addition we consider technologies that might be required to realize the benefits of optimized grinding wheels. A non-contact wheel-to- workpiece proximity sensor may provide a means of monitoring wheel wear and thus wheel position, for wheels that exhibit high wear rates in exchange for improved surface finish.
Date: November 12, 1996
Creator: Taylor, J. S.; Piscotty, M. S. & Blaedel, K. L.
System: The UNT Digital Library
Systems reliability analysis for the national ignition facility (open access)

Systems reliability analysis for the national ignition facility

A Reliability, Availability and Maintainability (RAM) analysis was initiated for the National Ignition Facility (NIF). The NIF is an inertial confinement fusion research facility designed to achieve controlled thermonuclear reaction; the preferred site for the NIF is the Lawrence Livermore National Laboratory (LLNL). The NIF RAM analysis has three purposes: (1) to allocate top level reliability and availability goals for the systems, (2) to develop an operability model for optimum maintainability, and (3) to determine the achievability of the allocated goals of the RAM parameters for the NIF systems and the facility operation as a whole. An allocation model assigns the reliability and availability goals for front line and support systems by a top-down approach; reliability analysis uses a bottom-up approach to determine the system reliability and availability from component level to system level.
Date: June 12, 1996
Creator: Majumdar, K.C.; Annese, C.E.; MacIntyre, A.T. & Sicherman, A.
System: The UNT Digital Library
Sub-50 femtosecond, multiterwatt Ti:sapphire laser system (open access)

Sub-50 femtosecond, multiterwatt Ti:sapphire laser system

We discuss a Ti:sapphire laser system based on chirped pulse amplification which produces over 750 mJ in sub-50 femtosecond pulses. We also describe a novel, all-reflective stretcher with a stretching ratio of 30,000.
Date: March 12, 1996
Creator: Banks, P. S.; Zweiback, J.; Fochs, S. N.; Stuart, B. C. & Perry, M. D.
System: The UNT Digital Library
Wavelet/scalar quantization compression standard for fingerprint images (open access)

Wavelet/scalar quantization compression standard for fingerprint images

US Federal Bureau of Investigation (FBI) has recently formulated a national standard for digitization and compression of gray-scale fingerprint images. Fingerprints are scanned at a spatial resolution of 500 dots per inch, with 8 bits of gray-scale resolution. The compression algorithm for the resulting digital images is based on adaptive uniform scalar quantization of a discrete wavelet transform subband decomposition (wavelet/scalar quantization method). The FBI standard produces archival-quality images at compression ratios of around 15 to 1 and will allow the current database of paper fingerprint cards to be replaced by digital imagery. The compression standard specifies a class of potential encoders and a universal decoder with sufficient generality to reconstruct compressed images produced by any compliant encoder, allowing flexibility for future improvements in encoder technology. A compliance testing program is also being implemented to ensure high standards of image quality and interchangeability of data between different implementations.
Date: June 12, 1996
Creator: Brislawn, C.M.
System: The UNT Digital Library