384 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Sound Waves"

open access

Effects of crack geometry and material behavior on scattering by cracks for QNDE applications

In work carried out on this project, the usual mathematical modeling of ultrasonic wave scattering by flaws is being extended to account for several typical characteristics of fatigue and stress-corrosion cracks, and the environment of such cracks. Work has been completed on scattering by macrocrack-microcrack configurations. We have also investigated reflection and transmission by a flaw plane consisting of an infinite array of randomly oriented cracks. In another investigation the propagation… more

Date: September 15, 1989

Creator: Achenbach, J. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Thin-film characterization and flaw detection. Final report, February 1, 1993--November 31, 1997

The objectives were to determine the elastic constants of thin films deposited on substrates, to measure residual stress and to detect and characterize defects in thin film substrate configurations. There are many present and potential applications of configurations consisting of a thin film deposited on a substrate. Thin films that are deposited to improve the hardness and/or the thermal properties of surfaces were of principal interest in this work. Thin film technology does, however, also in… more

Date: February 25, 1998

Creator: Achenbach, J. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

PRODUCTION WELL PERFORMANCE ENHANCEMENT USING SONICATION TECHNOLOGY

The objective of this project is to develop a sonic well performance enhancement technology that focuses on near wellbore formations. In order to successfully achieve this objective, a three-year project has been defined with each year consisting of four tasks. The first task is the laboratory-scale study whose goal is to determine the underlying principles of the technology. The second task will develop a scale-up mathematical model to serve as the design guide for tool development. The third … more

Date: December 17, 2003

Creator: Adewumi, Michael A.; Ityokumbul, M. Thaddeus; Watson, Robert W.; Farias, Mario; Heckman, Glenn; Olanrewaju, Johnson et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Investigation of ultrasonic wave interactions with fluid-saturated porous rocks

Investigation of ultrasonic waves, especially the slow compressional wave, with fluid-saturated porous solids, especially rocks. This research effort should fine applications in the geophysical evaluation of fluid-bearing porous rocks where parameters such as tortuosity, permeability, saturation level, and internal impurities are difficult to measure by conventional techniques. The proposed investigation may be divided into three major subtasks: Experimental study of surface wave propagation on… more

Date: January 1, 1990

Creator: Adler, L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

(Investigation of ultrasonic wave interactions with fluid-saturated porous rocks)

During the last two years we have continued our investigation of ultrasonic wave propagation in fluid-filled porous materials. First, we studied the feasibility of using different surface modes to characterize both synthetic and natural rocks. We introduced a novel experimental technique based on the direct generation of surface waves by edge excitation. We used two low-frequency (100--500 kHz) shear transducers in pitch-catch mode to launch and receive the ultrasonic surface wave. The contact … more

Date: January 1, 1992

Creator: Adler, L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A micromachined surface acoustic wave sensor for detecting inert gases

Surface acoustic wave (SAW) sensors must be specifically designed for each application because many variables directly affect the acoustic wave velocity. In the present work, the authors have designed, fabricated, and tested an SAW sensor for detection of metastable states of He. The sensor consists of two sets of micromachined interdigitated transducers (IDTs) and delay lines fabricated by photolithography on a single Y-cut LiNbO{sub 3} substrate oriented for Z-propagation of the SAWs. One set… more

Date: December 31, 1996

Creator: Ahuja, S.; Hersam, M.; Ross, C.; Chien, H. T. & Raptis, A. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sodium boiling detection in LMFBRs (Phase I). 5th quarterly technical progress report, July 1, 1975--October 31, 1975

Progress summarized includes the design of a gamma heated subassembly for sodium boiling experiments and an experiment showing that neutronic noise and acoustic noise caused by sodium boiling are highly correlated in a wide frequency band about the bubble repetition frequency. (DG)

Date: January 1, 1975

Creator: Albrecht, R. W. & McCormick, N. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Sodium boiling detection in LMFBRs (Phase I). 6th quarterly technical progress report, November 1, 1975--December 31, 1975

Progress summarized includes the design of a gamma heated subassembly for sodium boiling experiments. (DG)

Date: January 1, 1975

Creator: Albrecht, R. W. & McCormick, N. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Pattern recognition and tomography using crosswell acoustic data

Measurements of the travel time of acoustic signals transmitted between wells at the Department of Energy Multi-Well Experiment site (MWX) near Rifle, Colorado, are processed and analyzed. Interpretations relevant to sand geometry and continuity have proved possible through inspection of the signal travel time plotted against the coordinates of transmitter and receiver wellbore positions, or against the depth of receiver and ray path inclination. The continuity of several sands between wells is… more

Date: January 1, 1985

Creator: Albright, James N.; Terry, Darrell A. & Bradley, Christopher R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Staggered-grid finite-difference acoustic modeling with the Time-Domain Atmospheric Acoustic Propagation Suite (TDAAPS).

This document is intended to serve as a users guide for the time-domain atmospheric acoustic propagation suite (TDAAPS) program developed as part of the Department of Defense High-Performance Modernization Office (HPCMP) Common High-Performance Computing Scalable Software Initiative (CHSSI). TDAAPS performs staggered-grid finite-difference modeling of the acoustic velocity-pressure system with the incorporation of spatially inhomogeneous winds. Wherever practical the control structure of the co… more

Date: May 1, 2005

Creator: Aldridge, David Franklin; Collier, Sandra L. (U.S. Army Research Laboratory); Marlin, David H. (U.S. Army Research Laboratory); Ostashev, Vladimir E. (NOAA/Environmental Technology Laboratory); Symons, Neill Phillip & Wilson, D. Keith (U.S. Army Cold Regions Research Engineering Lab.)

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Limitations for heterodyne detection of Brillouin scattered light

One means by which elastic properties of a material may be determined is measuring sound wave velocities in the material, from which elastic moduli of interest can be computed. Velocity can be measured by conventional piezoelectric transduction techniques, by applying laser ultrasonics, or by using Brillouin-scattering methods. Brillouin-scattering techniques for determining the sound wave velocity are particularly attractive since they are completely noninvasive. Only a probe beam of light is … more

Date: January 1, 1995

Creator: Allemeier, R. T.; Wagner, J. W. & Telschow, K. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Synthesis of periodic mesoporous silica thin films

We have synthesized periodic mesoporous silica thin films from homogeneous solutions. To synthesize the films, a thin layer of a pH 7 micellar coating solution that contains TMOS (tetramethoxysilane) is dip or spin-coated onto Si wafers, borosilicate glass, or quartz substrates. NH3 gas is diffused into the solution and causes rapid hydrolysis and condensation of the TMOS and the formation of periodic mesoporous thin films within 10 seconds. Combination of homogenous solutions and rapid product… more

Date: June 1, 1996

Creator: Anderson, M. T.; Martin, J. E.; Odinek, J. G. & Newcomer, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

BBN technical memorandum W1310 hydroacoustic network capability studies

This report summarizes work performed under contract to Lawrence Livermore National Laboratory during the period 1 August to 30 November 1997. Four separate tasks were undertaken during this period which investigated various aspects of hydroacoustic network performance using the Hydroacoustic Coverage Assessment Model (HydroCAM). The purpose of this report is to document each of these tasks.

Date: December 1, 1997

Creator: Angell, J., LLNL

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Reactor Vessel and Core Two-Phase Flow Ultrasonic Densitometer

A local ultrasonic density (LUD) detector has been developed by EG and G Idaho, Inc., at the Idaho National Engineering Laboratory (INEL) for the Loss-of-Fluid Test (LOFT) reactor vessel and core two-phase flow density measurements. The principle of operating the sensor is the change in propagation time of a torsional ultrasonic wave in a metal transmission line as a function of the density of the surrounding media. A theoretical physics model is presented which represents the total propagation… more

Date: January 1, 1979

Creator: Arave, A. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ultrasonic Density Detector for Vessel and Reactor Core Two-Phase Flow Measurements

A local ultrasonic density (LUD) detector has been developed by EG and G Idaho, Inc., at the Idaho National Engineering Laboratory for the Loss-of-Fluid Test (LOFT) reactor vessel and core two-phase flow density measurements. The principle of operating the sensor is the change in propagation time of a torsional ultrasonic wave in a metal transmission line as a function of the density of the surrounding media. A theoretical physics model is presented which represents the total propagation time a… more

Date: January 1, 1979

Creator: Arave, A. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Evaluation of infrasonic detection capability for the CTBT/IMS

Evaluation of infrasonic detection capability for the International Monitoring System of the Comprehensive Test Ban Treaty (IMS/CTBT) is made with respect to signal analysis and global coverage. Signal analysis is anecdotally reviewed with respect to composite power, correlation and F-statistic detection algorithms. In the absence of adaptive pre-filtering, either cross-correlation or F-statistic detection is required. As an unbounded quantity, the F-statistic offers potentially greater sensiti… more

Date: September 1, 1996

Creator: Armstrong, W.T.; Whitaker, R.W. & Olson, J.V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent progress in commensurate-incommensurate phase transformations. [Hg/sub 3/-delta AsF/sub 6/; 2H polytype of TaSe/sub 2/]

Three topics are discussed. (1) the nature of long wavelength excitations in Hg/sub 3/-delta AsF/sub 6/, where gapless excitations in addition to the conventional acoustic modes are observed. (2) Thiourea, in which new commensurate phases can be induced by an external electric field. (3) Discommensurations in 2HTaSe/sub 2/, where recent electron diffraction and high resolution x-ray data combine with neutron results to establish a quite complex and subtle behavior. 9 figures.

Date: August 1, 1982

Creator: Axe, J.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of a GaAs Monolithic Surface Acoustic Wave Integrated Circuit

An oscillator technology using surface acoustic wave delay lines integrated with GaAs MESFET electronics has been developed for GaAs-based integrated microsensor applications. The oscillator consists of a two-port SAW delay line in a feedback loop with a four-stage GaAs MESFET amplifier. Oscillators with frequencies of 470, 350, and 200 MHz have been designed and fabricated. These oscillators are also promising for other RF applications.

Date: March 8, 1999

Creator: Baca, A. G.; Casalnuovo, S. C.; Drummond, T. J.; Frye, G. C.; Heller, E. J.; Hietala, V. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Acoustic Wave Chemical Microsensors in GaAs

High sensitivity acoustic wave chemical microsensors are being developed on GaAs substrates. These devices take advantage of the piezoelectric properties of GaAs as well as its mature microelectronics fabrication technology and nascent micromachining technology. The design, fabrication, and response of GaAs SAW chemical microsensors are reported. Functional integrated GaAs SAW oscillators, suitable for chemical sensing, have been produced. The integrated oscillator requires 20 mA at 3 VK, opera… more

Date: September 20, 1998

Creator: Baca, Albert G.; Heller, Edwin J.; Frye-Mason, Gregory C.; Reno, John L.; Kottenstette, Richard; Casalnuovo, Stephen A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Direct and indirect measures of speech articulator motions using low power EM sensors

Low power Electromagnetic (EM) Wave sensors can measure general properties of human speech articulator motions, as speech is produced. See Holzrichter, Burnett, Ng, and Lea, J.Acoust.Soc.Am. 103 (1) 622 (1998). Experiments have demonstrated extremely accurate pitch measurements (< 1 Hz per pitch cycle) and accurate onset of voiced speech. Recent measurements of pressure-induced tracheal motions enable very good spectra and amplitude estimates of a voiced excitation function. The use of the m… more

Date: May 12, 1999

Creator: Barnes, T; Burnett, G; Gable, T; Holzrichter, J F & Ng, L

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ultrasonic angle beam profiling in steel using an EMAT receiver

A system for measuring the beam profile of angle beam search units in steel is described. This technique employs an electromagnetic acoustic transducer (EMAT). The EMAT is sensitive to shear waves polarized parallel to the surface and requires no couplant. A steel block with surfaces cut at angles normal to the ultrasonic beam propagation direction is used. The amplitude distribution of the angle beam is measured at the surface of the test block using the EMAT receiver. The information is recor… more

Date: January 1, 1982

Creator: Becker, F. L. & Busse, L. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Innovative Technology Development Program. Final summary report

Through the Office of Technology Development (OTD), the U.S. Department of Energy (DOE) has initiated a national applied research, development, demonstration, testing, and evaluation program, whose goal has been to resolve the major technical issues and rapidly advance technologies for environmental restoration and waste management. The Innovative Technology Development (ITD) Program was established as a part of the DOE, Research, Development, Demonstration, Testing, and Evaluation (RDDT&E) Pro… more

Date: August 1, 1995

Creator: Beller, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Method for chemically analyzing a solution by acoustic means

A method and apparatus are described for determining a type of solution and the concentration of that solution by acoustic means. Generally stated, the method consists of: immersing a sound focusing transducer within a first liquid filled container; locating a separately contained specimen solution at a sound focal point within the first container; locating a sound probe adjacent to the specimen, generating a variable intensity sound signal from the transducer; measuring fundamental and multipl… more

Date: November 1995

Creator: Beller, L. S.

Item Type: Patent

Partner: UNT Libraries Government Documents Department

open access

Feasibility studies for the Sonic Sensor System for noninvasive temperature measurement in the food processing industry

Feasibility studies for development of the Sonic Sensor System to measure temperature in the interior of particulates during food processing are described. The method involves tomography-based acquisition and interpretation of speed of sound data. The method is found to be feasible, and representative engineering problems and other technical issues are identified. A two-step approach to concept commercialization, involving replacement of the present puncture-and-thermometer method is convention… more

Date: September 1, 1991

Creator: Beller, L.S.; Mikesell, C.R.; Taylor, S.C. & Tow, D.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department