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Modeling and Imaging Flexural Plate Wave Devices (open access)

Modeling and Imaging Flexural Plate Wave Devices

Sandia National Laboratories is developing a new form of flexural plate wave device (FPW) for sensor applications. In this device, Lorentz forces cause out of plane vibrations in a silicon nitride membrane. Current induced in transducer lines on the membrane provides information about the amplitude and phase of these surface vibrations. By tracking the large amplitude vibrations that occur at resonant frequencies, it is possible to infer information about loading on the membrane. In fabricating FPWs, it is important to understand the impact that minor defects can have on operation. Through modeling and testing, they are developing resilient designs that provide large amplitude signals with a high tolerance to defects. A finite element model has been developed to perform design trade-off studies, and results from the model are being verified with a unique measurement system that can image Angstrom scale displacements at vibrational frequencies up to 800 kHz. Results from FPW modeling and imaging efforts are presented in this paper.
Date: July 9, 1999
Creator: Adkins, D. R.; Butler, M. A.; Chu, A. S. & Schubert, W. K.
Object Type: Article
System: The UNT Digital Library
Infrastructure, Technology and Applications of Micro-Electro-Mechanical Systems (MEMS) (open access)

Infrastructure, Technology and Applications of Micro-Electro-Mechanical Systems (MEMS)

A review is made of the infrastructure, technology and capabilities of Sandia National Laboratories for the development of micromechanical systems. By incorporating advanced fabrication processes, such as chemical mechanical polishing, and several mechanical polysilicon levels, the range of micromechanical systems that can be fabricated in these technologies is virtually limitless. Representative applications include a micro-engine driven mirror, and a micromachined lock. Using a novel integrated MEMS/CMOS technology, a six degree-of-freedom accelerometer/gyroscope system has been designed by researchers at U.C. Berkeley and fabricated on the same silicon chip as the CMOS control circuits to produce an integrated micro-navigational unit.
Date: July 9, 1999
Creator: Allen, J. J.; Jakubczak, J. F.; Krygowski, T. W.; Miller, S. L.; Montague, S.; Rodgers, M. S. et al.
Object Type: Article
System: The UNT Digital Library
Nuclear Futures Analysis and Scenario Building (open access)

Nuclear Futures Analysis and Scenario Building

This LDRD project created and used advanced analysis capabilities to postulate scenarios and identify issues, externalities, and technologies associated with future ''things nuclear''. ''Things nuclear'' include areas pertaining to nuclear weapons, nuclear materials, and nuclear energy, examined in the context of future domestic and international environments. Analysis tools development included adaptation and expansion of energy, environmental, and economics (E3) models to incorporate a robust description of the nuclear fuel cycle (both current and future technology pathways), creation of a beginning proliferation risk model (coupled to the (E3) model), and extension of traditional first strike stability models to conditions expected to exist in the future (smaller force sizes, multipolar engagement environments, inclusion of actual and latent nuclear weapons (capability)). Accomplishments include scenario development for regional and global nuclear energy, the creation of a beginning nuclear architecture designed to improve the proliferation resistance and environmental performance of the nuclear fuel cycle, and numerous results for future nuclear weapons scenarios.
Date: July 9, 1999
Creator: Arthur, E. D.; Beller, D.; Canavan, G. H.; Krakowski, R. A.; Peterson, P. & Wagner, R. L.
Object Type: Report
System: The UNT Digital Library
Corrosion Behavior of Plasma-Passivated Cu (open access)

Corrosion Behavior of Plasma-Passivated Cu

A new approach is being pursued to study corrosion in Cu alloy systems by using combinatorial analysis combined with microscopic experimentation (the Combinatorial Microlab) to determine mechanisms for copper corrosion in air. Corrosion studies are inherently difficult because of complex interactions between materials and environment, forming a multidimensional phase space of corrosion variables. The Combinatorial Microlab was specifically developed to address the mechanism of Cu sulfidation, which is an important reliability issue for electronic components. This approach differs from convention by focusing on microscopic length scales, the relevant scale for corrosion. During accelerated aging, copper is exposed to a variety of corrosive environments containing sulfidizing species that cause corrosion. A matrix experiment was done to determine independent and synergistic effects of initial Cu oxide thickness and point defect density. The CuO{sub x} was controlled by oxidizing Cu in an electron cyclotron resonance (ECR) O{sub 2} plasma, and the point defect density was modified by Cu ion irradiation. The matrix was exposed to 600 ppb H{sub 2}S in 65% relative humidity air atmosphere. This combination revealed the importance of oxide quality in passivating Cu and prevention of the sulfidizing reaction. A native oxide and a defect-laden ECR oxide both react at …
Date: July 9, 1999
Creator: Barbour, J. C.; Braithwaite, J. W.; Son, K.-A.; Sullivan, J. P.; Missert, N, & Sorensen, N. R.
Object Type: Article
System: The UNT Digital Library
Physical Protection System Upgrades - Optimizing for Performance and Cost (open access)

Physical Protection System Upgrades - Optimizing for Performance and Cost

CPA--Cost and Performance Analysis--is an architecture that supports analysis of physical protection systems and upgrade options. ASSESS (Analytic System and Software for Evaluating Security Systems), a tool for evaluating performance of physical protection systems, currently forms the cornerstone for evaluating detection probabilities and delay times of the system. Cost and performance data are offered to the decision-maker at the systems level and to technologists at the path-element level. A new optimization engine has been attached to the CPA methodology to automate analyses of many combinations (portfolios) of technologies. That engine controls a new analysis sequencer that automatically modifies ASSESS PPS files (facility descriptions), automatically invokes ASSESS Outsider analysis and then saves results for post-processing. Users can constrain the search to an upper bound on total cost, to a lower bound on level of performance, or to include specific technologies or technology types. This process has been applied to a set of technology development proposals to identify those portfolios that provide the most improvement in physical security for the lowest cost to install, operate and maintain at a baseline facility.
Date: July 9, 1999
Creator: Bouchard, Ann M. & Hicks, Mary Jane
Object Type: Article
System: The UNT Digital Library
Perry Daily Journal (Perry, Okla.), Vol. 106, No. 133, Ed. 1 Friday, July 9, 1999 (open access)

Perry Daily Journal (Perry, Okla.), Vol. 106, No. 133, Ed. 1 Friday, July 9, 1999

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History
[Letter from George W. Bush to Charles Francis, July 19, 1999] (open access)

[Letter from George W. Bush to Charles Francis, July 19, 1999]

A letter from George W. Bush to Charles C. Francis thanking him for serving as a vice chair during Bush's campaign fundraising reception in D.C.
Date: July 9, 1999
Creator: Bush, George W.
Object Type: Letter
System: The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Friday, July 9, 1999 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Friday, July 9, 1999

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Sealy News (Sealy, Tex.), Vol. 112, No. 56, Ed. 1 Friday, July 9, 1999 (open access)

The Sealy News (Sealy, Tex.), Vol. 112, No. 56, Ed. 1 Friday, July 9, 1999

Semiweekly newspaper from Sealy, Texas that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Chionsini, Brandi
Object Type: Newspaper
System: The Portal to Texas History
Altus Times (Altus, Okla.), Vol. 100, No. 95, Ed. 1 Friday, July 9, 1999 (open access)

Altus Times (Altus, Okla.), Vol. 100, No. 95, Ed. 1 Friday, July 9, 1999

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Cole, Carol
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Baytown Sun (Baytown, Tex.), Vol. 77, No. 216, Ed. 1 Friday, July 9, 1999 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 77, No. 216, Ed. 1 Friday, July 9, 1999

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Dobbs, Gary
Object Type: Newspaper
System: The Portal to Texas History
Measurement of the B Quark Fragmentation Function in Z{sup 0} Decays (open access)

Measurement of the B Quark Fragmentation Function in Z{sup 0} Decays

We present preliminary results of a new measurement of the inclusive b quark fragmentation function in Z{sup 0} decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 150,000 hadronic Z{sup 0} events recorded in the SLD experiment at SLAC between 1996 and 1997. The small and stable SLC beam spot and the CCD-based vertex detector are used to reconstruct topological B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used in this technique. We measure the B energy with good efficiency and resolution over the full kinematic range. We compare the measured scaled B hadron energy distribution with several functional forms of the B hadron energy distribution and predictions of several models of b quark fragmentation. Several functions are excluded by the data. The average scaled energy of the weakly decaying B hadron is measured to be x{sub B} = 0.714 {+-} 0.005 (stat) {+-} 0.007 (syst) {+-} 0.002 (model) (preliminary).
Date: July 9, 1999
Creator: Dong, Danning
Object Type: Report
System: The UNT Digital Library
Structure and Dynamics of Quasi-Ordered Systems (open access)

Structure and Dynamics of Quasi-Ordered Systems

The functionality of many materials of both fundamental and technological interest is often critically dependent on the nature and extent of any disorder that may be present. In addition, it is often difficult to understand the nature of disorder in quite well ordered systems. There is therefore an urgent need to develop better tools, both experimental and computational, for the study of such quasi-ordered systems. To this end, the authors have used neutron diffraction studies in an attempt to locate small metal clusters or molecules randomly distributed inside microporous catalytic materials. Specifically, they have used pair distribution function (PDF) analysis, as well as inelastic neutron scattering (INS) spectroscopy, to study interactions between adsorbate molecules and a microporous matrix. They have interfaced these experimental studies with computations of PDF analysis as well as modeling of the dynamics of adsorbates. These techniques will be invaluable in elucidating the local structure and function of many of these classes of materials.
Date: July 9, 1999
Creator: Eckert, Juergen; Redondo, Antonio; Henson, Neil J.; Wang, Wanshu & Hay, P. Jeffrey
Object Type: Report
System: The UNT Digital Library
Energy Matters, July 1999 (open access)

Energy Matters, July 1999

This issue of Energy Matters focuses on selling an energy-efficient project to management. There are also articles on combined heat and power systems, inspecting steam traps for efficient system, root cause failure analysis on AC induction motors, and performance optimization tips.
Date: July 9, 1999
Creator: Erickson, E.
Object Type: Book
System: The UNT Digital Library
Neutrino Physics at Fermilab (open access)

Neutrino Physics at Fermilab

The Liquid Scintillator Neutrino Detector (LSND), located at the LANSCE (formerly LAMPF) linear accelerator at Los Alamos National Laboratory, has seen evidence for the oscillation of neutrinos, and hence neutrino mass. That discovery was the impetus for this LDRD project, begun in 1996. The goal of this project was to define the appropriate technologies to use in a follow up experiment and to set in place the requirements for such an experiment.
Date: July 9, 1999
Creator: Federspiel, F.; Garvey, G.; Louis, W.C.; Mills, G.B.; Tayloe, R.; Sandberg, V. et al.
Object Type: Report
System: The UNT Digital Library
Bent solenoid simulations for the muon cooling experiment (open access)

Bent solenoid simulations for the muon cooling experiment

The muon collider captures pions using solenoidal fields. The pion are converted to muons as they are bunched in an RF phase rotation system. Solenoids are used to focus the muons as their emitance is reduced during cooling. Bent solenoids are used to sort muons by momentum. This report describes a bent solenoid system that is part of a proposed muon cooling experiment. The superconducting solenoid described in this report consists of a straight solenoid that is 1.8 m long, a bent solenoid that is 1.0 m to 1.3 m long and a second straight solenoid that is 2.6 m long. The bent solenoid bends the muons over an angle of 57.3 degrees (1 radian). The bent solenoid has a minor coil radius (to the center of the coil) that is 0.24 m and a major radius (of the solenoid axis) of 1.0 m. The central induction along the axis is 3.0 T There is a dipole that generates an induction of 0.51 T, perpendicular to the plane of the bend, when the induction on the bent solenoid axis is 3.0 T.
Date: July 9, 1999
Creator: Green, M. A.; Eyssa, Y. M.; Kenney, S.; Miller, J. R. & Prestemon, S.
Object Type: Article
System: The UNT Digital Library
Refrigeration options for the Advanced Light Source Superbend Dipole Magnets (open access)

Refrigeration options for the Advanced Light Source Superbend Dipole Magnets

The 1.9 GeV Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) produces photons with a critical energy of about 3.1 kev at each of its thirty-six 1.3 T gradient bending magnets. It is proposed that at three locations around the ring the conventional gradient bending magnets be replaced with superconducting bending magnets with a maximum field of 5.6 T. At the point where the photons are extracted, their critical energy will be about 12 keV. In the beam lines where the SuperBend superconducting magnets are installed, the X ray brightness at 20 keV will be increased over two orders of magnitude. This report describes three different refrigeration options for cooling the three SuperBend dipoles. The cooling options include: (1) liquid helium and liquid nitrogen cryogen cooling using stored liquids, (2) a central helium refrigerator (capacity 70 to 100 W) cooling all of the SuperBend magnets, (3) a Gifford McMahon (GM) cryocooler on each of the dipoles. This paper describes the technical and economic reasons for selecting a small GM cryocooler as the method for cooling the SuperBend dipoles on the LBNL Advanced Light Source.
Date: July 9, 1999
Creator: Green, M. A.; Hoyer, E. H.; Schlueter, R. D.; Taylor, C. E.; Zbasnik, J. & Wang, S. T.
Object Type: Article
System: The UNT Digital Library
Close Encounters of Asteroids and Comets to Planets (open access)

Close Encounters of Asteroids and Comets to Planets

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors find by numerical simulations that the elongated-potato shape that is characteristic of Earth-crossing asteroids (ECAs) is likely the result of previous close tidal encounters with Earth. Some meteoroids graze the atmosphere of Earth before returning to space (at reduced speed). They used a spherical atmospheric model to study such grazers to find the condition under which they are captured into gravitationally bound orbits around Earth. They find that for about every thousand iron asteroids that hit the Earth, one is captured into a gravitational-bound orbit. Some fraction of these captured objects will have their orbits stabilized for many revolutions by tidal encounters with the Moon and the sun. They have also studied how the damage produced by such grazing and near-grazing asteroids differs from that produced by asteroids that hit Earth more directly.
Date: July 9, 1999
Creator: Hills, J.G.; Goda, M.P. & Solem, J.C.
Object Type: Report
System: The UNT Digital Library
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 255, Ed. 1 Friday, July 9, 1999 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 255, Ed. 1 Friday, July 9, 1999

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Horn, Richard A.
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Boerne Star (Boerne, Tex.), Vol. 94, No. 55, Ed. 1 Friday, July 9, 1999 (open access)

The Boerne Star (Boerne, Tex.), Vol. 94, No. 55, Ed. 1 Friday, July 9, 1999

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Keasling, Edna & Fierro, Jennifer
Object Type: Newspaper
System: The Portal to Texas History
The Hopkins County Echo (Sulphur Springs, Tex.), Vol. 204, No. 28, Ed. 1 Friday, July 9, 1999 (open access)

The Hopkins County Echo (Sulphur Springs, Tex.), Vol. 204, No. 28, Ed. 1 Friday, July 9, 1999

Weekly newspaper from Sulphur Springs, Texas that includes local, state, and national news along with advertising.
Date: July 9, 1999
Creator: Keys, Scott & Lamb, Bill
Object Type: Newspaper
System: The Portal to Texas History
Molecular Dynamics Simulation of the Structure and Properties of Lithium Phosphate Glasses (open access)

Molecular Dynamics Simulation of the Structure and Properties of Lithium Phosphate Glasses

A new forcefield model was developed for the computer simulation of phosphate materials that have many important applications in the electronics and biomedical industries. The model provides a fundamental basis for the evaluation of phosphate glass structure and thermodynamics. Molecular dynamics simulations of a series of lithium phosphate glass compositions were performed using the forcefield model. A high concentration of three-membered rings (P{sub 3}O{sub 3}) occurs in the glass of intermediate composition (0.2 Li{sub 2}O {center_dot} 0.8P{sub 2}O{sub 5}) that corresponds to the minimum in the glass transition temperature curve for the compositional series. Molecular orbital calculations of various phosphate ring clusters indicate an increasing stabilization of the phosphate ring structure going from two- to four-membered rings.
Date: July 9, 1999
Creator: Liang, J-J; Cygan, R.T. & Alam, T.M.
Object Type: Article
System: The UNT Digital Library
Measurement of the Probability for Gluon Splitting into b{bar b} in Z{sup 0} Decays (open access)

Measurement of the Probability for Gluon Splitting into b{bar b} in Z{sup 0} Decays

We present a preliminary measurement of the rate of gluon splitting into bottom quarks, g {r_arrow} b{bar b}, in hadronic Z{sup 0} decays collected by SLD between 1996 and 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. 4-jet events were identified, and a topological vertex-mass technique was applied to each jet in order to identify b or {bar b} jets. The upgraded CCD based vertex detector gives very high B-tagging efficiency, especially for B hadrons of the low energies typical of this process. The two most nearly collinear b/{bar b} jets were tagged as originating from g {r_arrow} b{bar b}. We measured the rate of secondary b/{bar b} production per hadronic event, g{sub b{bar b}}, to be (3.07 {+-} 0.71(stat.) {+-} 0.66(syst.)) x 10{sup {minus}3} (preliminary).
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library
A Preliminary Direct Measurement of the Parity-Violating Coupling of the Z{sup 0} to Strange Quarks, A{sub s} (open access)

A Preliminary Direct Measurement of the Parity-Violating Coupling of the Z{sup 0} to Strange Quarks, A{sub s}

We present an updated direct measurement of the parity-violating coupling of the Z{sup 0} to strange quarks, A{sub s}, derived from the full SLD data sample of approximately 550,000 hadronic decays of Z{sup 0} bosons produced with a polarized electron beam and recorded by the SLD experiment at SLAC between 1993 and 1998. Z{sup 0} {r_arrow} s{bar s} events are tagged by the presence in each event hemisphere of a high-momentum K{sup {+-}}, K{sub s} or {Lambda}{sup 0}/{bar {Lambda}}{sup 0} identified using the Cherenkov Ring Imaging Detector and/or a mass tag. The CCD vertex detector is used to suppress the background from heavy-flavor events. The strangeness of the tagged particle is used to sign the event thrust axis in the direction of the initial s quark. The coupling A{sub s} is obtained directly from a measurement of the left-right-forward-backward production asymmetry in polar angle of the tagged s quark. The background from u{bar u} and d{bar d} events is measured from the data, as is the analyzing power of the method for s{bar s} events. We measure: A{sub s} = 0.85 {+-} 0.06(stat.) {+-} 0.07(syst.)(preliminary).
Date: July 9, 1999
Creator: Muller, David
Object Type: Report
System: The UNT Digital Library