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  • 1
    Online Resource
    Online Resource
    An investigation of the capabilities of a short hydrophone array towed by an ocean glider
    Acoustical Society of America (ASA) ; 2007
    In:  The Journal of the Acoustical Society of America Vol. 122, No. 5_Supplement ( 2007-11-01), p. 3009-3009
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 122, No. 5_Supplement ( 2007-11-01), p. 3009-3009
    Abstract: During the Shallow Water Experiment (SW06) a Webb Slocum glider, deployed by Rutgers University, demonstrated that gliders are promising vehicles for towing short acoustic arrays. The gliders saw-tooth trajectory allows for sampling the water column at varying depths and ranges. Further, the glider provides a low-speed platform, allowing for a flow-noise free towed array, which is ideal for the processing of low level signals. One attractive application for glider-towed arrays is target tracking. By using the passive synthetic aperture effect, coupled with a near-field model for the signal, the coordinates of an acoustic source can be estimated using a Kalman filter, but without the necessity of the maneuver normally required by bearings-only tracking. This is possible since the large aperture traced out by the glider permits wavefront curvature to be exploited for range estimation. Using synthetic narrowband data, it is shown that the range and bearing of a low-level acoustic source can be estimated without changing the gliders course. The algorithm is based on an Unscented Kalman Filter. Also, an approach for the broadband problem is outlined. [Work sponsored by the Office of Naval Research.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2942749
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2007
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Underwater gliders as acoustic receiving platforms
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2526-2526
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 130, No. 4_Supplement ( 2011-10-01), p. 2526-2526
    Abstract: Acoustic data were collected on a single hydrophone towed by a Webb Slocum glider deployed by Rutgers University, during the shallow water experiment (SW06), on the continental shelf, of New Jersey. The geometry of the experiment provided for adequate recording of the 224 and 400 Hz tomography sources. A follow-up study of the New Jersey Tuckerton Field Station provided a rudimentary noise analysis showing the glider's capabilities as an acoustic receiving platform. The glider's saw-tooth glide profile allows for vertical sampling of the water column with periodic surfaces for GPS fixes and data transfer via satellite phone. The glider provides a low-noise and low-speed platform, potentially enabling detection of low level signals. [Work sponsored by the Office of Naval Research.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3655082
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
    Online Resource
    Measurements of 3-D propagation effects at a shelfbreak front
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3222-3222
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3222-3222
    Abstract: Acoustic data collected on two Webb Slocum gliders deployed by Rutgers University during the Shallow Water Experiment (SW06) on the continental shelf off New Jersey are presented. Acoustic recording systems were attached to the two gliders, which also collected oceanographic data. These gliders periodically surfaced for GPS fixes and data transfer via satellite phone. A major goal of these measurements was to quantify 3-D propagation effects including the horizontal analog to the classical Lloyd’s mirror. The Lloyd’s mirror effect is produced by the fact that fronts can totally internally reflect sound incident upon them at low grazing angles. The direct and reflected arrivals can add up to produce an interference pattern in range, potentially increasing the received intensity level by 6 dB [Lynch et al., IEEE J. Ocean. Eng., in press]. The gliders crossed the shelfbreak front at ranges of approximately 20 km from the sources and in water depths of approximately 80 m. Measurements of the acoustic arrivals from 224 and 400 Hz tomography sources are compared to 3D modeling results. The increase in the intensity level predicted by the horizontal ray-vertical mode model is discussed. [Work supported by Office of Naval Research.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4788189
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Analysis and modeling of broadband airgun data influenced by nonlinear internal waves
    Acoustical Society of America (ASA) ; 2004
    In:  The Journal of the Acoustical Society of America Vol. 116, No. 6 ( 2004-12-01), p. 3404-3422
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 116, No. 6 ( 2004-12-01), p. 3404-3422
    Abstract: To investigate acoustic effects of nonlinear internal waves, the two southwest tracks of the SWARM 95 experiment are considered. An airgun source produced broadband acoustic signals while a packet of large nonlinear internal waves passed between the source and two vertical linear arrays. The broadband data and its frequency range (10–180 Hz) distinguish this study from previous work. Models are developed for the internal wave environment, the geoacoustic parameters, and the airgun source signature. Parabolic equation simulations demonstrate that observed variations in intensity and wavelet time–frequency plots can be attributed to nonlinear internal waves. Empirical tests are provided of the internal wave-acoustic resonance condition that is the apparent theoretical mechanism responsible for the variations. Peaks of the effective internal wave spectrum are shown to coincide with differences in dominant acoustic wavenumbers comprising the airgun signal. The robustness of these relationships is investigated by simulations for a variety of geoacoustic and nonlinear internal wave model parameters.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.1819499
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2004
    detail.hit.zdb_id: 1461063-2
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  • 5
    Online Resource
    Online Resource
    Thimble into Ladybird: Nietzsche, Frobenius, and Bachofen in the Later Work of D. H. Lawrence
    Walter de Gruyter GmbH ; 1978
    In:  arca Vol. 13, No. 1-3 ( 1978), p. 161-176
    Details
    In: arca, Walter de Gruyter GmbH, Vol. 13, No. 1-3 ( 1978), p. 161-176
    Type of Medium: Online Resource
    ISSN: 0003-7982 , 1613-0642
    URL: Article
    DOI: 10.1515/arca.1978.13.1-3.161
    RVK:
    EA 1000
    Language: English
    Publisher: Walter de Gruyter GmbH
    Publication Date: 1978
    detail.hit.zdb_id: 120646-1
    detail.hit.zdb_id: 2158551-9
    SSG: 7,12
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  • 6
    Online Resource
    Online Resource
    Frequency analysis of broadband acoustic signals propagating through nonlinear internal waves
    Acoustical Society of America (ASA) ; 2000
    In:  The Journal of the Acoustical Society of America Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2830-2830
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2830-2830
    Abstract: Nonlinear internal waves along the ocean thermocline are known to affect modal compositions and other properties of acoustic signals. Such nonlinear waves were observed during the SWARM 95 Orthogonal Propagation Experiment, where extensive data were collected from two broadband sources. One source was a 30-s linear frequency modulated sweep signal, and the other was a 0.1-s airgun shot. Both sources were repeated every minute and received by two vertical linear arrays several kilometers away. Sound speed profiles were measured near the source and the receiver arrays simultaneously. The influences of internal waves on the broadband frequency behavior of received and simulated signals are described. Features of energy spectral density and of transmission loss versus frequency plots are used to detect resonant frequencies where anomalous loss occurs. A time-frequency analysis of received signals at several ranges is performed to determine modal propagation characteristics, including modal transitions of the signals passing through the internal waves. An objective of this study is to link acoustic signal behavior to internal wave properties such as wavelength, packet length, and amplitude. [Work supported by ONR.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.429134
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2000
    detail.hit.zdb_id: 1461063-2
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  • 7
    Online Resource
    Online Resource
    A dear searcher into comparisons: The rhetoric of Ellen Goodman
    Informa UK Limited ; 1984
    In:  Quarterly Journal of Speech Vol. 70, No. 1 ( 1984-02), p. 69-79
    Details
    In: Quarterly Journal of Speech, Informa UK Limited, Vol. 70, No. 1 ( 1984-02), p. 69-79
    Type of Medium: Online Resource
    ISSN: 0033-5630 , 1479-5779
    URL: Article
    DOI: 10.1080/00335638409383677
    RVK:
    EQ 1000
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 1984
    detail.hit.zdb_id: 2066946-X
    SSG: 7,11
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  • 8
    Online Resource
    Online Resource
    The forum
    Informa UK Limited ; 1968
    In:  Quarterly Journal of Speech Vol. 54, No. 2 ( 1968-04), p. 154-163
    Details
    In: Quarterly Journal of Speech, Informa UK Limited, Vol. 54, No. 2 ( 1968-04), p. 154-163
    Type of Medium: Online Resource
    ISSN: 0033-5630 , 1479-5779
    URL: Article
    DOI: 10.1080/00335636809382885
    RVK:
    EQ 1000
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 1968
    detail.hit.zdb_id: 2066946-X
    SSG: 7,11
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  • 9
    Online Resource
    Online Resource
    Analysis of internal wave interactions with broadband acoustic signals propagating along the shelf during the SWARM’95 experiment
    Acoustical Society of America (ASA) ; 2000
    In:  The Journal of the Acoustical Society of America Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2830-2830
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 107, No. 5_Supplement ( 2000-05-01), p. 2830-2830
    Abstract: A multi-institution experiment was conducted in 1995 on the New Jersey continental shelf to assess the Shallow Water Acoustic propagation in Random Media (SWARM’95). Two major source/receiver geometries were established. One was parallel to the continental shelf edge and the other was perpendicular. The orthogonal propagation consisted of two broadband sources transmitting signals perpendicular to the direction of internal wave field. The first signal was a transient airgun source (0.1-s duration), while the second was a linear frequency modulated sweep (30-s duration). Placed above and below the thermocline, these sources were transmitting signals every minute for a few hours at one location. Here we present a 2-h segment of these observations during 4 August 1995 when nonlinear internal waves were present. The transmissions were received by two vertical line arrays at different ranges and angles from the source. The dependence on the azimuth between the internal waves and the acoustic transmissions was examined. It is found that sound speed fluctuations induced by internal waves cause a 10–12-min temporal variations in the intensity of received signals. These temporal variations are azimuthally dependent since the environment is anisotropic due to internal solitary waves. [Work supported by ONR.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.429312
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2000
    detail.hit.zdb_id: 1461063-2
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  • 10
    Online Resource
    Online Resource
    Generalized response of a sphere embedded in a viscoelastic medium excited by an ultrasonic radiation force
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 130, No. 3 ( 2011-09-01), p. 1133-1141
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 130, No. 3 ( 2011-09-01), p. 1133-1141
    Abstract: The response of an embedded sphere in a viscoelastic medium excited by acoustic radiation force has been studied in both the time- and frequency-domains. This model is important because it can be used to characterize the viscoelastic properties of the medium by fitting the response to the theoretical model. The Kelvin–Voigt model has been used exclusively in these models. An extension to the previously reported models is described so that any viscoelastic rheological model can be used. This theoretical development describes the generalized embedded sphere response both in the time and frequency domains. Comparing the results from derivations in both domains showed very good agreement with a median absolute error (MAE) ranging from 0.0044 to 0.0072. Good agreement is demonstrated with finite element model simulations and the theory with a MAE of 0.006. Lastly, results for characterization of gelatin and rubber materials with the new theory are shown where the MAE values were used to determine which rheological model best describes the measured responses.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3613939
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
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