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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
Experimental and Theoretical Investigation of Multiphase Flow in Fractured Porous media, SUPRI TR-116, Topical Report
The fluid transfer parameters between rock matrix and fracture are not well known. Consequently, simulation of fractured reservoirs uses, in general, very crude and unproven hypotheses such as zero capillary pressure in the fracture and/or relative permeability linear with saturation. In order to improve the understanding of flow in fractured media, an experimental study was conducted and numerical simulations of the experiments were made. A laboratory flow apparatus was built to obtain data on water- air imbibition and oil-water drainage displacements in horizontal single-fractured block systems. For this purpose, two configurations have been used: a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. During the experiments, porosity and saturation measurements along the cores have been made utilizing an X-ray Computerized Tomography (CT) scanner. Saturation images were reconstructed in 3-D to observe matrix-fracture interactions. Differences in fluid saturations and relative permeabilities caused by changes in fracture width have also been analyzed.
Date:
August 9, 1999
Creator:
Akin, Serhat; Castanier, Louis M. & German, Edgar Rene Rangel
Object Type:
Report
System:
The UNT Digital Library
Design and testing of cryogenic target systems
General Atomics (GA) together with the University of Rochester/Laboratory for Laser Energetics (UR/LLE) and Los Alamos National Laboratory (LANL), has designed the OMEGA Cryogenic Target System. This system fills, cools, and layers DT targets and places them in the center of the OMEGA Target Chamber. All equipment was procured, assembled, and tested at GA and UR/LLE. GA along with Lawrence Livermore National Laboratory and LANL is designing a test unit to evaluate the key process parameters and design issues associated with fielding cryogenic targets on the National Ignition Facility.
Date:
September 9, 1999
Creator:
Alexander, N. B.; Baugh, W. A.; Bernat, T. P.; Besenbruch, G. E.; Boline, K. K.; Brown, L. C. et al.
Object Type:
Article
System:
The UNT Digital Library
Oral History Interview with Alton O. Crawley, March 9, 1999
Access:
Use of this item is restricted to the UNT Community
Interview with electrical engineer and Army veteran Alton O. Crawley. The interview includes Crawley's personal experiences about the China-Burma-India Theater during World War II, having pre-war civilian jobs in radio/communications work, training for Office of Strategic Services operations, being assigned to Wudu, China, coast watching activities and radio transmissions, and various miscellaneous accounts of his tour of duty in China. The interview includes an appendix with various letters accompanied by a list detailing them, and an itinerary for per diem claims.
Date:
March 9, 1999
Creator:
Alexander, William J. & Crawley, Alton O.
Object Type:
Book
System:
The UNT Digital Library
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 101, Ed. 1 Tuesday, February 9, 1999
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
February 9, 1999
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 121, Ed. 1 Tuesday, March 9, 1999
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
March 9, 1999
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
The Oklahoma Daily (Norman, Okla.), Vol. 83, No. 137, Ed. 1 Friday, April 9, 1999
Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date:
April 9, 1999
Creator:
Allam, Heather
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
MEMS Functional Validation Using the Configuration Space Approach to Simulation and Analysis
We have developed an interactive computer-aided design program that supports mechanical design of devices fabricated in surface micro-machining processes. The program automates kinematic analysis via a novel configuration space computation code, performs real-time simulation, and supports functional parametric design. Designers can visualize system function under a range of operating conditions, can find and correct design flaws, and can optimize performance. We used the program to detect and correct a design flaw in a micro-mechanical indexing mechanism fabricated at Sandia with the SUMMiT process.
Date:
March 9, 1999
Creator:
Allen, J. & Sacks, E.
Object Type:
Article
System:
The UNT Digital Library
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
National Geoscience Data Repository System, Phase III: Implementation and Operation of the Repository
The NGDRS steering committee met at Unocal's offices on October 1, 1998 in Sugar Land, Texas to review and discuss issues of data transfer and the continued development of the Stapleton prospect for establishment of a national core repository. Company representatives reaffirmed their commitment to donate geoscience data to the NGDRS once appropriate facilities are available.
Date:
November 9, 1999
Creator:
American Geological Institute
Object Type:
Report
System:
The UNT Digital Library
An Experimental Investigation of Foam Flow in Homogeneous and Heterogeneous Porous Media, SUPRI TR-112
Foam is used to reduce the high mobility of gas-drive fluids and improve the contact between oil and these injected fluids. We require a better understanding of the effect of surfactant concentration on foam flow in porous media. Besides this, the literature on foam flow and transport in heterogeneous systems is sparse although the field situation is primarily heterogeneous and multidimensional. In this study, foam flow experiments were conducted first in homogeneous sand packs to investigate the effect of surfactant concentration on foam flow and then a heterogeneous experimental setup was prepared to observe heterogeneity and multidimensional flow effects on foam propagation. The homogeneous core experiments were conducted in a cylindrical aluminum core holder that was packed with a uniform Ottawa sand. Sand permeability is about 7.0 Darcy. The experiments were interpreted in terms of evolution of in-situ water saturation as a function of time by the usage of CT scanner, cumulative water, and pressure drop across the core. At very low surfactant concentration, no significant benefit was observed. But when stable foam generation started sweep efficiency (water recovery), breakthrough time, and pressure drop increased as surfactant concentration increased.
Date:
August 9, 1999
Creator:
Apaydin, Osman G.; Bertin, Henri; Castanier, Louis M. & Kovscek, Anthony R.
Object Type:
Report
System:
The UNT Digital Library
Fabrication, Packaging, and Performance of VCSELs and Photodetectors for Space Applications
Optocouplers are used for a variety of applications aboard spacecraft including electrical isolation, switching and power transfer. Commercially available light emitting diode (LED)-based optocouplers have experienced severe degradation of light output due to extensive displacement damage occurring in the semiconductor lattice caused by energetic proton bombardment. A new optocoupler has been designed and fabricated which utilizes vertical cavity surface emitting laser (VCSEL) and resonant cavity photodetector (RCPD) technologies for the optocoupler emitter and detector, respectively. Linear arrays of selectively oxidized GaAs/AlGaAs VCSELS and RCPDS, each designed to operate at a wavelength of 850nm, were fabricated using an airbridge contacting scheme. The airbridged contacts were designed to improve packaging yields and device reliability by eliminating the use of a polyimide planarizing layer which provided poor adhesion to the bond pad metallization. Details of the airbridged optocoupler fabrication process are reported. Discrete VCSEL and RCPD devices were characterized at temperatures between {minus}100 to 100 C. Devices were packaged in a face-to-face configuration to form a single channel optocoupler and its performance was evaluated under conditions of high-energy proton bombardment.
Date:
March 9, 1999
Creator:
Armendariz, M. G.; Briggs, R. D.; Choquette, K. D.; Geib, K. M. & Serkland, D. K.
Object Type:
Article
System:
The UNT Digital Library
Toward a common component architecture for high-performance scientific computing
This paper describes work in progress to develop a standard for interoperability among high-performance scientific components. This research stems from growing recognition that the scientific community must better manage the complexity of multidisciplinary simulations and better address scalable performance issues on parallel and distributed architectures. Driving forces are the need for fast connections among components that perform numerically intensive work and parallel collective interactions among components that use multiple processes or threads. This paper focuses on the areas we believe are most crucial for such interactions, namely an interface definition language that supports scientific abstractions for specifying component interfaces and a ports connection model for specifying component interactions.
Date:
June 9, 1999
Creator:
Armstrong, R.; Gannon, D.; Geist, A.; Katarzyna, K.; Kohn, S.; McInnes, L. et al.
Object Type:
Article
System:
The UNT Digital Library
Savannah River Site Environmental Data for 1998
This document presents data from Savannah River Site routine effluent monitoring and environmental surveillance programs.
Date:
June 9, 1999
Creator:
Arnett, M.
Object Type:
Report
System:
The UNT Digital Library
Savannah River Site Environmental Report for 1998
The mission at the Savannah River Site (SRS) is focused primarily on support of the national defense, nonproliferation, and environmental cleanup. SRS-through its prime operating contractor, Westinghouse Savannah River Company-continues to maintain a comprehensive environmental monitoring program.
Date:
June 9, 1999
Creator:
Arnett, M.
Object Type:
Report
System:
The UNT Digital Library
[Letter from Ken Arnold to Charlyne Creger, June 9, 1999]
Letter from Ken Arnold to Charlyne Creger requesting information about the Women Ariforce Service Pilots and the Soviet women pilots for The Remembering Project he is working on.
Date:
June 9, 1999
Creator:
Arnold, Ken
Object Type:
Letter
System:
The Portal to Texas History
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
Safety and environmental advantages of using tritium-lean targets for inertial fusion
While traditional inertial fusion energy target designs typically use equimolar portions of deuterium and tritium and have areal densities ({rho}r) of {approx} 3 g/cm{sup 2}, significant safety and environmental (S and E) advantages may be obtained through the use of high-density ({rho}r {approx} 10 g/cm{sup 2}) targets with tritium components as low as 0.5%. Such targets would absorb much of the neutron energy within the target and could be self-sufficient from a tritium breeding point of view. Tritium self-sufficiency within the target would free target chamber designers from the need to use lithium-bearing blanket materials, while low inventories within each target would translate into low inventories in target fabrication facilities. Absorption of much of the neutron energy within the target, the extremely low tritium inventories, and the greatly moderated neutron spectrum, make ''tritium-lean'' targets appear quite attractive from an S and E perspective.
Date:
August 9, 1999
Creator:
Arzeni, S.; Latkowski, J. F.; Logan, B. G.; Meier, W. R.; Moir, R. W.; Perkins, L. J. et al.
Object Type:
Article
System:
The UNT Digital Library
Optical Spectroscopy Measurements of Shock Waves Driven by Intense Z-Pinch Radiation
Z-pinches created using the Z accelerator generate {approximately}220 TW, 1.7 MJ radiation pulses that heat large ({approximately}10 cm{sup 3}) hohlraums to 100-150 eV temperatures for times of order 10 nsec. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 nsec duration in 6-mm-diameter samples. In this paper we demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy measurements because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metalization in transparent materials, and characterization of …
Date:
April 9, 1999
Creator:
Asay, J.; Bailey, J. E.; Carlson, A. L.; Chandler, G. A.; Hall, C. A.; Hanson, D. et al.
Object Type:
Article
System:
The UNT Digital Library
Novel Metal-Sulfur-Based Air-Stable Passivation of GaAs with Very Low Surface State Densities
A new air-stable electronic surface passivation for GaAs and other III-V compound semiconductors that employs sulfur and a suitable metal ion, e.g., Zn, and that is robust towards plasma dielectric deposition has been developed. Initial improvements in photoluminescence are twice that of S-only treatments and have been preserved for >11 months with SiO{sub x}N{sub y} dielectric encapsulation. Photoluminescence and X-ray photoelectron spectroscopies indicate that the passivation consists of two major components with one being stable for >2 years in air. This process improves heterojunction bipolar transistor current gain for both large and small area devices.
Date:
August 9, 1999
Creator:
Ashby, Carol I.H.; Baca, Albert G.; Chang, P.-C; Hafich, M.J.; Hammons, B.E. & Zavadil, Kevin R.
Object Type:
Article
System:
The UNT Digital Library
Novel ultrasound scintillator
This development project addressed the need for a faster, less expensive method of transmission ultrasound. It utilized the principle of frustrated total internal reflection to transduce acoustic pressure into optical modulation. These data were acquired an entire 2D plane at a time. This report described the modeling and verification of a final sensor design.
Date:
February 9, 1999
Creator:
Ashby, E; Ciarlo, D; Kallman, J S & Thomas, G
Object Type:
Report
System:
The UNT Digital Library
Implementation of smoothing by spectral dispersion on Beamlet and NIF
The performance of the Beamlet laser with one dimensional smoothing by spectral dispersion (1D SSD) implemented is investigated. Measurements of the near field beam quality, nonlinear breakup, and transmission through spatial filter pinholes show a modest effect only at large SSD divergence. No measurable effect was found at the divergence level planned for indirect drive ignition experiments. The efficiency of conversion to the third harmonic was also measured with SSD present and found to be somewhat larger than expected from an ideal plane wave model.
Date:
June 9, 1999
Creator:
Auerbach, J M; Moran, B D; Murray, J E; Rothenberg, J E; Wegner, P J & Weiland, T L
Object Type:
Article
System:
The UNT Digital Library
Particle Production in 158.A GeV 208Pb+208Pb Collisions
The production of neutral pions in 158A GeV {sup 208}Pb+{sup 208}Pb collisions has been studied in the WA98 experiment. The centrality dependence of the neutral pion production is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with more than about 50 participants. The transverse mass spectrum is analyzed in terms of a thermal model with hydrodynamic expansion. The high accuracy and large kinematic coverage of the measurement constrains the extracted freeze-out parameters, and provides information on the freeze-out velocity profile.
Date:
January 9, 1999
Creator:
Awes, T.C.
Object Type:
Article
System:
The UNT Digital Library
High Energy Physics division semiannual report of research activities, January 1, 1998--June 30, 1998.
This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1, 1998 through June 30, 1998. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.
Date:
March 9, 1999
Creator:
Ayres, D. S.; Berger, E. L.; Blair, R.; Bodwin, G. T.; Drake, G.; Goodman, M. C. et al.
Object Type:
Report
System:
The UNT Digital Library