226 Matching Results

Search Results

Advanced search parameters have been applied.

PHASE 1 Technical Letter Report – TS-00358: Portable Acoustic Contraband Detector

Description: This TLR provides the results of all PNNL managed activities on this project, and contains a description of the data acquisition configuration and testing protocols, results and conclusions from this work. This TLR is part of the final deliverables package submitted to the client during the Phase 1 Go/No-Go meeting in Richland, Washington, on July 31, 2007.
Date: July 31, 2007
Creator: Diaz, Aaron A.
Partner: UNT Libraries Government Documents Department

Acoustic 3D imaging of dental structures

Description: Our goals for the first year of this three dimensional electodynamic imaging project was to determine how to combine flexible, individual addressable; preprocessing of array source signals; spectral extrapolation or received signals; acoustic tomography codes; and acoustic propagation modeling code. We investigated flexible, individually addressable acoustic array material to find the best match in power, sensitivity and cost and settled on PVDF sheet arrays and 3-1 composite material.
Date: February 1, 1997
Creator: Lewis, D.K.; Hume, W.R. & Douglass, G.D.
Partner: UNT Libraries Government Documents Department

Closing remarks on Faraday Discussion 107: Interactions of acoustic waves with thin films and interfaces

Description: The papers in this Faraday Discussion represent the state-of-the-art in using acoustic devices to measure the properties of thin films and interfaces. Sauerbrey first showed that the mass sensitivity of a quartz crystal could be used to measure the thickness of vacuum-deposited metals. Since then, significant progress has been made in understanding other interaction mechanisms between acoustic devices and contacting media. Bruckenstein and Shay and Kanazawa and Gordon showed that quartz resonators could be operated in a fluid to measure surface mass accumulation and fluid properties. The increased understanding of interactions between acoustic devices and contacting media has allowed new information to be obtained about thin films and interfaces. These closing remarks will summarize the current state of using acoustic techniques to probe thin films and interfaces, describe the progress reported in this Faraday Discussion, and outline some remaining problems. Progress includes new measurement techniques, novel devices, new applications, and improved modeling and data analysis.
Date: November 1, 1997
Creator: Martin, S.J.
Partner: UNT Libraries Government Documents Department

Humanitarian mine detection by acoustic resonance

Description: The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL ...
Date: March 1, 1998
Creator: Kercel, S.W.
Partner: UNT Libraries Government Documents Department

Solid Rocket Motor Acoustic Testing

Description: Acoustic data are often required for the determination of launch and powered flight loads for rocket systems and payloads. Such data are usually acquired during test firings of the solid rocket motors. In the current work, these data were obtained for two tests at a remote test facility where we were visitors. This paper describes the data acquisition and the requirements for working at a remote site, interfacing with the test hosts.
Date: March 31, 1999
Creator: Rogers, J.D.
Partner: UNT Libraries Government Documents Department

Hydroacoustic Evaluation of Juvenile Salmonid Passage at The Dalles Dam Spillway, 2006

Description: The objective of this study was to determine detailed vertical, horizontal, intensive, and diel distributions of juvenile salmonid passage at the spillway at The Dalles Dam from April 12 to July16, 2006. These data are being applied in the Spillway Improvements Program to position release pipes for direct injury and mortality studies and to provide baseline data for assessment of the vortex suppression devices scheduled for deployment in 2007. We estimated fish distributions from hydroacoustic data collected with split-beam transducers arrayed across Bays 1 through 9 and 14. Spill at ~20 kcfs per bay was bulked at Bays 1-6, although the other bays were opened at times during the study to maintain a 40% spill percentage out of total project discharge. The vertical distribution of fish was skewed toward the surface during spring, but during summer, passage peaked at 2-3 m above the spillway ogee. Fish passage rates (number per hour) and fish densities (number per kcfs) were highest at Bay 6, followed by passage at Bay 5. This result comports with spillway horizontal distribution data from radio telemetry and hydroacoustic studies in 2004. The vertical and horizontal distribution of fish passage at bays 5 and 6 was much more variable during spring than summer and more variable at bay 5 than bay 6. Diel distribution data revealed that fish passage was highest during 0600-0700 h in spring; otherwise passage was reasonably uniform on a diel basis. This study substantiates the purpose of the spillway vortex suppression device to re-distribute downstream migrants away from Bay 6 toward Bays 1-5.
Date: May 24, 2007
Creator: Johnson, Gary E.; Khan, Fenton; Skalski, John R.; Rakowski, Cynthia L.; Richmond, Marshall C. & Serkowski, John A.
Partner: UNT Libraries Government Documents Department

A comparison of the response of a captive carried store to both reverberant wave acoustic excitation and the field environment

Description: Stores that are carried on high performance military aircraft are exposed to severe vibroacoustic environments from several different sources. Sandia National Laboratories conducted a test program to determine the viability of reproducing these field 10 environments with a combined vibroacoustic test. This paper will present the results of that test series emphasizing the methods used to derive the laboratory inputs that produce the {open_quotes}best{close_quotes} possible match for the field response.
Date: October 1, 1996
Creator: Cap, J.S.; Togami, T.C. & Hollingshead, J.R.
Partner: UNT Libraries Government Documents Department

Nondestructive testing of ceramic components: Cooperative research and development agreement completion report

Description: In a joint Cooperative Research and Development Agreement (CRADA) between Martin Marietta Energy Systems (MMES) and an industrial partner, Y-12 has been evaluating nondestructive evaluation (NDE) techniques to identify the quality of high strength aluminum oxide tubes used in laser applications. In Phase I, several NDE techniques were developed to inspect the tubes. In Phase II a correlation between detected defects, actual failure mode and strength of the tubes was developed. In Phase II the industrial partner supplied tubes manufactured under a variety of conditions and containing material defects expected from process control variations. The tubes were inspected at MMES utilizing a variety of available acoustic techniques. After inspection, ring tensile specimens were fabricated to determine the tensile strength. The data were evaluated utilizing Weibull statistics to determine the statistical impact of the defects upon strength and correlate the data with the nondestructive evaluations of the tubes and observed defect distribution.
Date: December 22, 1994
Creator: Carpenter, D.A.; Dews, T.W.; Moyer, M.W. & Oakes, R.E.
Partner: UNT Libraries Government Documents Department

Molecular recognition in gas sensing: Results from acoustic wave and in-situ FTIR measurements

Description: Surface acoustic wave (SAW) measurements were combined with direct, in-situ molecular spectroscopy to understand the interactions of surface-confined sensing films with gas-phase analytes. This was accomplished by collecting Fourier-transform infrared external-reflectance spectra (FTIR-ERS) on operating SAW devices during dosing of their specifically coated surfaces with key analytes.
Date: June 1, 1998
Creator: Hierlemann, A.; Ricco, A.J.; Bodenhoefer, K. & Goepel, W.
Partner: UNT Libraries Government Documents Department

Monolithic GaAs surface acoustic wave chemical microsensor array

Description: A four-channel surface acoustic wave (SAW) chemical sensor array with associated RF electronics is monolithically integrated onto one GaAs IC. The sensor operates at 690 MHz from an on-chip SAW based oscillator and provides simple DC voltage outputs by using integrated phase detectors. This sensor array represents a significant advance in microsensor technology offering miniaturization, increased chemical selectivity, simplified system assembly, improved sensitivity, and inherent temperature compensation.
Date: March 9, 2000
Creator: HIETALA,VINCENT M.; CASALNUOVO,STEPHEN A.; HELLER,EDWIN J.; WENDT,JOEL R.; FRYE-MASON,GREGORY CHARLES & BACA,ALBERT G.
Partner: UNT Libraries Government Documents Department

Origins of viscoelastic dissipation in self-assembled organic monolayers

Description: Although self-assembled monolayers (SAMs) are promising candidates for interfacial lubricants in micro-electromechanical systems, the relationship between the monolayer structure and its viscoelastic properties is not understood. Using Acoustic Wave Damping (AWD), the authors have measured the complex shear modulus of linear alkane thiol monolayers, HS(CH{sub 2}){sub n{minus}1}CH{sub 3} denoted as C{sub n}, on Au(111)-textured substrates. The AWD technique measures the elastic energy storage and dissipative loss within a SAM adsorbed onto the electrodes of a quartz crystal microbalance. For C{sub 12}, C{sub 14} and C{sub 18} SAMs, the storage modulus increases with alkane chain length, but the loss modulus exhibits no systematic correlation. To investigate the origins of energy dissipation, the authors used a new, high-sensitivity oscillator circuit to simultaneously monitor the adsorption kinetics and acoustic damping during monolayer growth from the gas phase. For both C{sub 9} and C{sub 12} thiols, the dissipation in the growing monolayer can be correlated with distinct two-dimensional fluid phases and the nucleation and growth of condensed-phase islands.
Date: April 1, 1998
Creator: Shinn, N.D. & Michalske, T.A.
Partner: UNT Libraries Government Documents Department

Feasibility of High Frequency Acoustic Imaging for Inspection of Containments

Description: The Nuclear Regulatory Commission has a program at the Oak Ridge National Laboratory to provide assistance in their assessment of the effects of potential degradation on the structural integrity and Ieaktightness of metal containment vessels and steel liners of concrete containment in nuclear power plants. One of the program objectives is to identify a technique(s) for inspection of inaccessible portions of the containment pressure boundary. Acoustic imaging has been identified as one of these potential techniques. A numerical feasibility study investigated the use of high-frequency bistatic acoustic imaging techniques for inspection of inaccessible portions of the metallic pressure boundary of nuclear power plant containment. The range-dependent version of the OASES Code developed at the Massachusetts Institute of Technology was utilized to perform a series of numerical simulations. OASES is a well developed and extensively tested code for evaluation of the acoustic field in a system of stratified fluid and/or elastic layers. Using the code, an arbitrary number of fluid or solid elastic layers are interleaved, with the outer layers modeled as halfspaces. High frequency vibrational sources were modeled to simulate elastic waves in the steel. The received field due to an arbitrary source array can be calculated at arbitrary depth and range positions. In this numerical study, waves that reflect and scatter from surface roughness caused by modeled degradations (e.g., corrosion) are detected and used to identify and map the steel degradation. Variables in the numerical study included frequency, flaw size, interrogation distance, and sensor incident angle.Based on these analytical simulations, it is considered unlikely that acoustic imaging technology can be used to investigate embedded steel liners of reinforced concrete containment. The thin steel liner and high signal losses to the concrete make this application difficult. Results for portions of steel containment embedded in concrete are more encouraging in that ...
Date: August 1, 1998
Creator: Corrado, C.N.; Bondaryk, J.E. & Godino, V.
Partner: UNT Libraries Government Documents Department

Acoustic techniques in nuclear safeguards

Description: Acoustic techniques can be employed to address many questions relevant to current nuclear technology needs. These include establishing and monitoring intrinsic tags and seals, locating holdup in areas where conventional radiation-based measurements have limited capability, process monitoring, monitoring containers for corrosion or changes in pressure, and facility design verification. These acoustics applications are in their infancy with respect to safeguards and nuclear material management, but proof-of-principle has been demonstrated in many of the areas listed.
Date: July 1, 1995
Creator: Olinger, C.T. & Sinha, D.N.
Partner: UNT Libraries Government Documents Department

Multi-Exciter Vibroacoustic Simulation of Hypersonic Flight Vibration

Description: Many aerospace structures must survive severe high frequency, hypersonic, random vibration during their flights. The random vibrations are generated by the turbulent boundary layer developed along the exterior of the structures during flight. These environments have not been simulated very well in the past using a fixed-based, single exciter input with an upper frequency range of 2 kHz. This study investigates the possibility of using acoustic ardor independently controlled multiple exciters to more accurately simulate hypersonic flight vibration. The test configuration, equipment, and methodology are described. Comparisons with actual flight measurements and previous single exciter simulations are also presented.
Date: November 11, 1999
Creator: GREGORY,DANNY LYNN; CAP,JEROME S.; TOGAMI,THOMAS C.; NUSSER,MICHAEL A. & HOLLINGSHEAD,JAMES RONALD
Partner: UNT Libraries Government Documents Department

A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data

Description: Aerospace payloads, such as satellites, are subjected to vibroacoustic excitation during launch. Sandia's MTI satellite has recently been certified to this environment using a combination of base input random vibration and reverberant acoustic noise. The initial choices for the acoustic and random vibration test specifications were obtained from the launch vehicle Interface Control Document (ICD). In order to tailor the random vibration levels for the laboratory certification testing, it was necessary to determine whether vibration energy was flowing across the launch vehicle interface from the satellite to the launch vehicle or the other direction. For frequencies below 120 Hz this issue was addressed using response limiting techniques based on results from the Coupled Loads Analysis (CLA). However, since the CLA Finite Element Analysis FEA model was only correlated for frequencies below 120 Hz, Statistical Energy Analysis (SEA) was considered to be a better choice for predicting the direction of the energy flow for frequencies above 120 Hz. The existing SEA model of the launch vehicle had been developed using the VibroAcoustic Payload Environment Prediction System (VAPEPS) computer code [1]. Therefore, the satellite would have to be modeled using VAPEPS as well. As is the case for any computational model, the confidence in its predictive capability increases if one can correlate a sample prediction against experimental data. Fortunately, Sandia had the ideal data set for correlating an SEA model of the MTI satellite--the measured response of a realistic assembly to a reverberant acoustic test that was performed during MTI's qualification test series. The first part of this paper will briefly describe the VAPEPS modeling effort and present the results of the correlation study for the VAPEPS model. The second part of this paper will present the results from a study that used a commercial SEA software package [2] to study the ...
Date: November 15, 1999
Creator: CAP,JEROME S. & TRACEY,BRIAN
Partner: UNT Libraries Government Documents Department

Studies of ultrasonic beam spread in thick sections

Description: The use of hemispherical holes seems to be a valid procedure for monitoring both forward and lateral beam spread. Provided subsequent data analysis and checks show agreement, this type of reflector would be recommended for Code application. The preliminary evaluation of the 45/sup 0/, 2.25 MHz, 2.54-cm (1-in.) circular transducer case shows consistent results and determines an effective beam width that impacts scanning overlap or index. Additional work should be conducted in order to determine the effects of search unit differences (especially those affecting spectrum, near field, and small changes in the angular orientation). These search unit differences are expected to have even more effect on data for larger angles (e.g., 70/sup 0/). A decided improvement in the determination of the linear parameters such as slope and intercept could be obtained by using a greater number of side-drilled holes and hemispherical reflectors. The increased number of data points should greatly improve the quality of the linear fit and help determine reproducibility of the method.
Date: January 1, 1981
Creator: McClung, R.W.; Cook, K.V. & Latimer, P.J.
Partner: UNT Libraries Government Documents Department

Techniques for classifying acoustic resonant spectra

Description: A second-generation nondestructive evaluation (NDE) system that discriminates between different types of chemical munitions is under development. The NDE system extracts features from the acoustic spectra of known munitions, builds templates from these features, and performs classification by comparing features extracted from an unknown munition to a template library. Improvements over first-generation feature extraction template construction and classification algorithms are reported. Results are presented on the performance of the system and a large data set collected from surrogate-filled munitions.
Date: December 31, 1995
Creator: Roberts, R. S.; Lewis, P. S.; Chen, J. T. & Vela, O. A.
Partner: UNT Libraries Government Documents Department

04 nuclear safety: pressure piping crack monitoring detection of metal overstress by acoustic emission. Progress report, July-September 1966

Description: The three main areas of effort have been: (1) definition of the general acoustic response pattern related to the gross aspects of forming and extending a crack in various materials, (2) development of a monitor system prototype concept exclusive of transducers and (3) development of a suitable, high temperature transducer. Tests using double cantilever beam (DCB) specimens of various materials to establish conditions of crack formation and growth have indicated that material ductility is a major controlling factor in the acoustic response pattern. It appears to effect both acoustic emission intensity and the point in the crack formation-growth sequence at which the main emission occurs. A concept has been developed for the prototype of a full scale monitor system. Hardware development is being limited to the analyzer portion of the system at this time because it is the part most significant to demonstrating feasibility of the intended application. Signal level and signal rate are both being investigated as possible parameters for evaluating acoustic emission data. Of the various transducers for potential high temperature application, the capacitive or electrostatic transducer now looks most promising. A significant improvement in sensitivity has been achieved and a trial model used during recent tests produced generally satisfactory data. The sequence of effort on the program is being adjusted somewhat from that previously outlined. Some of the more detailed investigative phases will receive only moderate attention, temporarily, in favor of first demonstrating the basic feasibility of detecting acoustic emission and making a meaningful analysis under postulated service conditions.
Date: October 28, 1966
Creator: Hutton, P H
Partner: UNT Libraries Government Documents Department

Practical aspects of acoustic plastic pipe location

Description: Many gas distribution company operation and maintenance activities require precise knowledge of the location of buried plastic piping. Plastic pipe cannot be located if the tracer wire is gone or was never installed. Under sponsorship of the Southern California Gas Company, IGT successfully demonstrated an acoustic plastic pipe location technique and is developing the technique into a practical field instrument an acoustic signal is injected directly into the gas at a service. The acoustic signal travels in the gas in the pipes, not in the pipe wall. As the acoustic wave travels along the pipe, some of the sound radiates from the pipe through the soil to the surface of the ground. An array of sensors on the surface of the ground perpendicular to the pipe detects the acoustic signal, thereby locating the Pipe. Two different acoustic measurements are used. The first measurement locates the pipe to within {plus_minus} 3-ft. Then the second technique determines the location of the pipe to within {plus_minus} 6-in.
Date: December 31, 1993
Creator: Huebler, J. E.; Campbell, B. K. & Ching, G. K.
Partner: UNT Libraries Government Documents Department

Energy calibration scheme for acoustic emission

Description: The calibration technique described is an attempt to determine the actual energy release from the events causing emission bursts in beryllium and to quantitatively evaluate the effects of specimen geometry on the apparent energy per burst. (GHT)
Date: September 13, 1977
Creator: Adams, R. O. & Heiple, C. R.
Partner: UNT Libraries Government Documents Department

Method and apparatus for determining material structural integrity

Description: Disclosed are a nondestructive method and apparatus for determining the structural integrity of materials by combining laser vibrometry with damping analysis to determine the damping loss factor. The method comprises the steps of vibrating the area being tested over a known frequency range and measuring vibrational force and velocity vs time over the known frequency range. Vibrational velocity is preferably measured by a laser vibrometer. Measurement of the vibrational force depends on the vibration method: if an electromagnetic coil is used to vibrate a magnet secured to the area being tested, then the vibrational force is determined by the coil current. If a reciprocating transducer is used, the vibrational force is determined by a force gauge in the transducer. Using vibrational analysis, a plot of the drive point mobility of the material over the preselected frequency range is generated from the vibrational force and velocity data. Damping loss factor is derived from a plot of the drive point mobility over the preselected frequency range using the resonance dwell method and compared with a reference damping loss factor for structural integrity evaluation.
Date: January 1, 1994
Creator: Pechersky, M.J.
Partner: UNT Libraries Government Documents Department

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

Description: 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 include high {Tc} superconductor films, films for magnetic recording, superlattices and films for band-gap engineering and quantum devices. The studies that were carried out on this project also have relevance to these applications. Both the film and the substrate are generally anisotropic. A line-focus acoustic microscope has been used to measure the speed of surface acoustic waves (SAW) in the thin film/substrate system. This microscope has unique advantages for measurements in anisotropic media. Analytical and numerical techniques have been employed to extract the desired information on the thin film from the measured SAW data. Results include: (1) analytical and numerical techniques for the direct problem and for inverse methods; (2) measurements of homogeneous and superlattice film constants; (3) investigation of the effect of surface roughness and (4) measurements of residual stresses.
Date: February 25, 1998
Creator: Achenbach, J.D.
Partner: UNT Libraries Government Documents Department

Non-destructive evaluation techniques for chemical weapons destruction

Description: fThe safe and verifiable disposition, either by incineration or chemical neutralization of chemical warfare (CW) agents requires correct {ital a priori} identification of each munition or container to be processed. A variety of NDE techniques have been used or tested for the examination and characterization of munitions. In the U.S., three widely used techniques are X-ray radiography, acoustic resonance spectroscopy (ARS), and prompt gamma ray neutron activation analysis (PINS). The technical bases, instrumental implementations, and applications of the U.S. versions of these methods are briefly discussed. 10 refs., 2 figs., 1 tab.
Date: September 1, 1996
Creator: Hartwell, J.K. & Caffrey, A.J.
Partner: UNT Libraries Government Documents Department