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Title: Underwater acoustic channel estimation using multiple sources and receivers in shallow waters at very-high frequencies.
Creator: Kaddouri, Samar, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The underwater channel poses numerous challenges for acoustic communication. Acoustic waves suffer long propagation delay, multipath, fading, and potentially high spatial and temporal variability. In addition, there is no typical underwater acoustic channel; every body of water exhibits quantifiably different properties. Underwater acoustic modems are traditionally operated at low frequencies. However, the use of broadband, high frequency communication is a good alternative because of the...
Show moreThe underwater channel poses numerous challenges for acoustic communication. Acoustic waves suffer long propagation delay, multipath, fading, and potentially high spatial and temporal variability. In addition, there is no typical underwater acoustic channel; every body of water exhibits quantifiably different properties. Underwater acoustic modems are traditionally operated at low frequencies. However, the use of broadband, high frequency communication is a good alternative because of the lower background noise compared to low-frequencies, considerably larger bandwidth and better source transducer efficiency. One of the biggest problems in the underwater acoustic communications at high frequencies is time-selective fading, resulting in the Doppler spread. While many Doppler detection, estimation and compensation techniques can be found in literature, the applications are limited to systems operating at low frequencies contained within frequencies ranging from a few hundred Hertz to around 30 kHz.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004384, http://purl.flvc.org/fau/fd/FA00004384
Subject Headings: Adaptive signal processing, MIMO systems, Signal processing -- Ditigal techniques -- Mathematics, Underwater acoustic telemetry, Underwater acoustics -- Evaluation, Wireless communication systems
Format: Document (PDF)

Title: A Study of the Underwater Acoustic Propagation in a Turning Basin Modeled as a Three-Dimensional Duct Closed at One End Using the Method of Images.
Creator: Staska, Matthew D., Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A computer-efficient model of the underwater acoustic propagation m a shallow, three-dimensional duct closed at one end has been developed using the method of images. Presented in this research is the development of this three-dimensional method of images analysis for a rectangular duct. Using this analysis, a model of the impulse response of the acoustic channel is constructed. Also presented in this work is the actual impulse response collected during field experimentation in the south...
Show moreA computer-efficient model of the underwater acoustic propagation m a shallow, three-dimensional duct closed at one end has been developed using the method of images. Presented in this research is the development of this three-dimensional method of images analysis for a rectangular duct. Using this analysis, a model of the impulse response of the acoustic channel is constructed. Also presented in this work is the actual impulse response collected during field experimentation in the south turning basin of Port Everglades in Fort Lauderdale, Florida. The results demonstrate that the impulse response is modeled with a relative echo magnitude error of 1.62 dB at worst, and a relative echo location error varying between 0% and 4% when averaged across multiple measurements and sensor locations.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012557
Subject Headings: Underwater acoustics--Measurement, Wave motion, Theory of, Wave equation--Numerical solutions, Sound-waves--Transmission--Mathematical models
Format: Document (PDF)

Title: Mobile docking of REMUS-100 equipped with USBL-APS to an unmanned surface vehicle: a performance feasibility study.
Creator: Miranda, Mario II, Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The overall objective of this work is to evaluate the ability of homing and docking an unmanned underwater vehicle (Hydroid REMUS 100 UUV) to a moving unmanned surface vehicle (Wave-Adaptive Modular Surface Vehicle USV) using a Hydroid Digital Ultra-Short Baseline (DUSBL) acoustic positioning system (APS), as a primary navigation source. An understanding of how the UUV can rendezvous with a stationary USV first is presented, then followed by a moving USV. Inherently, the DUSBL-APS is...
Show moreThe overall objective of this work is to evaluate the ability of homing and docking an unmanned underwater vehicle (Hydroid REMUS 100 UUV) to a moving unmanned surface vehicle (Wave-Adaptive Modular Surface Vehicle USV) using a Hydroid Digital Ultra-Short Baseline (DUSBL) acoustic positioning system (APS), as a primary navigation source. An understanding of how the UUV can rendezvous with a stationary USV first is presented, then followed by a moving USV. Inherently, the DUSBL-APS is susceptible to error due to the physical phenomena of the underwater acoustic channel (e.g. ambient noise, attenuation and ray refraction). The development of an APS model has allowed the authors to forecast the UUV’s position and the estimated track line of the USV as determined by the DUSBL acoustic sensor. In this model, focus is placed on three main elements: 1) the acoustic channel and sound ray refraction when propagating in an in-homogeneous medium; 2) the detection component of an ideal DUSBL-APS using the Neyman-Pearson criterion; 3) the signal-to-noise ratio (SNR) and receiver directivity impact on position estimation. The simulation tool is compared against actual open water homing results in terms of the estimated source position between the simulated and the actual USBL range and bearing information.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004140, http://purl.flvc.org/fau/fd/FA00004140
Subject Headings: Adaptive signal processing, Mobile robots, Underwater acoustic telemetry
Format: Document (PDF)

Title: Performance and limitations of acoustic positioning using a tetrahedral ultra-short baseline array and an acoustic modem source transmitting frequency-hopped sequences.
Creator: Mohamed, Asif I., Florida Atlantic University, Beaujean, Pierre-Philippe, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The operation of unmanned underwater vehicles requires communications with other nearby vehicles as well as accurate positioning to prevent duplication of work, collisions and other mishaps. This thesis details the integration of an ultra-short baseline positioning system with four transducers arranged as a tetrahedron for use with the FAU Dual Purpose Acoustic Modem. The source position is estimated by processing coherently a series of frequency-hopped pulses to obtain a set of bearings,...
Show moreThe operation of unmanned underwater vehicles requires communications with other nearby vehicles as well as accurate positioning to prevent duplication of work, collisions and other mishaps. This thesis details the integration of an ultra-short baseline positioning system with four transducers arranged as a tetrahedron for use with the FAU Dual Purpose Acoustic Modem. The source position is estimated by processing coherently a series of frequency-hopped pulses to obtain a set of bearings, optimally combined through maximum likelihood estimation of the azimuth and elevation. A simulation has been implemented and experiments have been performed in a calibration tank. Model and experiments confirm that the accuracy of this system improves with the number of pulses and the signal-to-noise ratio. A mean positional error of 5.51% can be obtained with an SNR of 20 dB and a single processed pulse, the error decreases to 2.84% using six processed pulses.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13412
Subject Headings: Underwater navigation, Remote submersibles, Computer integrated manufacturing systems, Acoustical engineering, Underwater acoustics--Instruments
Format: Document (PDF)

Title: Maximum likelihood estimates of azimuth and elevation for a frequency-hopped active source using a tetrahedral ultra-short baseline.
Creator: Warin, Raphael., Florida Atlantic University, Beaujean, Pierre-Philippe, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Ultra-Short-BaseLine (USBL) is the most practical underwater acoustic positioning system for autonomous underwater vehicles because of its small space requirement. The objective of this research is to develop a USBL system capable of estimating a source location transmitting frequency-hopped tones sequences. Such sequences are characteristic of spread spectrum signaling used in underwater acoustic communication network. It must be able to provide azimuth and elevation of a modem-type source...
Show moreUltra-Short-BaseLine (USBL) is the most practical underwater acoustic positioning system for autonomous underwater vehicles because of its small space requirement. The objective of this research is to develop a USBL system capable of estimating a source location transmitting frequency-hopped tones sequences. Such sequences are characteristic of spread spectrum signaling used in underwater acoustic communication network. It must be able to provide azimuth and elevation of a modem-type source with an accuracy of 0.3 degrees; for both angles using the synchronization stage of the transmission. The acoustic antenna is composed of four transducers arranged as a tetrahedron. Using the model of Quazi and Lerro, which provides an expression for the variance of the bearing angle, azimuth and elevation of the transmitter are estimated employing maximum likelihood estimation. This system is simulated, tested and calibrated in a tank. Simulated results satisfy the requirement with a SNR of 32dB and 8 symbols. The latest experimental measurements present an accuracy of 3 degrees.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13135
Subject Headings: Underwater acoustics--Instruments, Underwater acoustic telemetry, Signal processing--Technique, Adaptive signal processing
Format: Document (PDF)

Title: High-speed acoustic communication in shallow water using spatio-temporal adaptive array processing.
Creator: Beaujean, Pierre-Philippe, Florida Atlantic University, LeBlanc, Lester R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A novel method of achieving stable high-speed underwater acoustic communication with a fairly low-complexity of implementation is proposed. The proposed approach is to split the space and time processing into two separate sub-optimal processes. As a result, processing complexity is significantly reduced and the instabilities associated with large tap vectors at large time-frequency spread products are reduced. The proposed space-time signal processing method utilizes a different beamformer...
Show moreA novel method of achieving stable high-speed underwater acoustic communication with a fairly low-complexity of implementation is proposed. The proposed approach is to split the space and time processing into two separate sub-optimal processes. As a result, processing complexity is significantly reduced and the instabilities associated with large tap vectors at large time-frequency spread products are reduced. The proposed space-time signal processing method utilizes a different beamformer optimization strategy compared to the time domain optimization strategy. This allows to separately adjust the adaptation parameters for the spatial and temporal characteristics of the signal, which have vastly different requirements. The time domain signal is subject to variations in phase that require rapid filter updates whereas the directional characteristics of the signal do not vary appreciably over the message length and do not require a rapid adaptation response. The proposed method allows for high-speed underwater acoustic communication in very shallow water using coherent modulation techniques, and offers a series of unique features: significant reduction of the signal-to-noise and interference ratio (SNIR), improvement of the bandwidth efficiency by reduction of the forward-error coding redundancy requirements, real-time evaluation of the time-spread by Doppler spread product (BL) and channel stability estimate. Experimental results demonstrate that stable acoustic communication can be achieved at rates of 32000 bits per second at a distance of 3 km, in 40 feet of water and in sea-state 2 conditions. Fast and slow fading properties of the channel are measured, as the BL product can vary by a decade in 116 ms, and by two decades within minutes, from 0.001 to 0.1. The real-time analysis shows a strong correlation between time spread, Doppler spread, spatial coherence of the acoustic channel and communication performance. Overall, this research provides more scientific and experimental ground to understand the limitations of multi-channel adaptive receiver techniques in terms of stability, hardware requirements and channel tracking capability.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/11952
Subject Headings: Underwater acoustic telemetry, Adaptive signal processing
Format: Document (PDF)

Title: Placement and Denoising of Total Magnetic Field Sensors Onboard an AUV in Support of Geophysical Navigation.
Creator: Cracchiolo, Timothy, Beaujean, Pierre-Philippe, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The objective of this thesis is to study the proper placement and denoising of Total Field Magnetometers (TFM) installed on an Autonomous Underwater Vehicle (AUV), in support of a long-term goal to perform geophysical navigation based on total field magnetic sensing. This new form of navigation works by using the magnetic field of the Earth as a source of reference to find the desired heading. The primary tools used in this experiment are a REMUS 100 AUV, a QuSpin scalar magnetometer, and a...
Show moreThe objective of this thesis is to study the proper placement and denoising of Total Field Magnetometers (TFM) installed on an Autonomous Underwater Vehicle (AUV), in support of a long-term goal to perform geophysical navigation based on total field magnetic sensing. This new form of navigation works by using the magnetic field of the Earth as a source of reference to find the desired heading. The primary tools used in this experiment are a REMUS 100 AUV, a QuSpin scalar magnetometer, and a TwinLeaf vector magnetometer. The Earth’s magnetic field was measured over periods of several hours to determine the range of values it provides under natural conditions. Digital filters were created to digitally reduce fluctuations caused by sources of external interference and sources of internal interference. To mitigate the issue of platform based interference, two methods were examined. These methods involved the use of the Tolles-Lawson model and Wavelet Multiresolution Analysis. The Tolles-Lawson model is used to determine the compensation coefficients from a calibration mission to mitigate the effects from the permanently detected magnetic field, the induced magnetic field, eddy currents. and the geomagnetic field. Wavelet multiresolution analysis follows the same basic steps as Fourier transformations and is used to analyze time series with power sources in motion over a frequency spectrum. Several acquisitions were run with the QuSpin in various locations around and along REMUS, and it was concluded that placing the sensor at the very front of the vessel which is approximately 1.8 [m] from the DC motor, with assistance from wavelet analysis was acceptable for the project.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00013972
Subject Headings: Autonomous underwater vehicles, Magnetometers, Magnetic fields, Remote sensing
Format: Document (PDF)

Title: ESTIMATION OF THE PHYSICAL PROPERTIES OF CORRODING REBAR IN REINFORCED CONCRETE USING BIOT-STOLL MODEL INVERSION.
Creator: Brogden, Matthew, Beaujean, Pierre-Philippe, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The detection of rebar corrosion in reinforced concrete is important due to the high costs of corrosion related damages to infrastructure. One such method of rebar corrosion lies in the use of non-destructive ultrasonic testing. To date, acoustic methods require either the training of an artificial neural network or a theory of acoustic wave propagation. Using a more complete acoustic model such as the Biot-Stoll model avoids algorithm training requirements by directly modeling the acoustic...
Show moreThe detection of rebar corrosion in reinforced concrete is important due to the high costs of corrosion related damages to infrastructure. One such method of rebar corrosion lies in the use of non-destructive ultrasonic testing. To date, acoustic methods require either the training of an artificial neural network or a theory of acoustic wave propagation. Using a more complete acoustic model such as the Biot-Stoll model avoids algorithm training requirements by directly modeling the acoustic environment. A problem with this method lies in the complexity of the model and the selection of free parameters. The problem of parameter selection is addressed by a series of targeted measurements using ultrasonic transducers on a set of existing reinforced concrete samples placed in a saltwater solution. This data can then be analyzed by a non-linear least squares solver to produce a better fit for the acoustic signal.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00014032
Subject Headings: Reinforcing bars--Corrosion, Reinforced concrete, Acoustics, Ultrasonics
Format: Document (PDF)

Title: Optimized Parameters Fitting of a Poro-Elastic Acoustic Model with Ultrasonic Measurements for the Monitoring of Corroding Rebar in Reinforced Concrete.
Creator: Shaffer, Samuel, Beaujean, Pierre-Philippe, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Traditional techniques of observing cracking within reinforced structures can be invasive, leading to an increased risk of added corrosion to structures already undergoing corrosive processes. The research presented in this document improves upon a nondestructive method for detecting early crack formation in reinforced concrete. This method includes using acoustic signaling to add a layer of salt water between the sensor and analyzed sample. Following the collection of surface and rebar echo...
Show moreTraditional techniques of observing cracking within reinforced structures can be invasive, leading to an increased risk of added corrosion to structures already undergoing corrosive processes. The research presented in this document improves upon a nondestructive method for detecting early crack formation in reinforced concrete. This method includes using acoustic signaling to add a layer of salt water between the sensor and analyzed sample. Following the collection of surface and rebar echo responses, an adapted version of the novel Biot-Stoll method is used to model sound propagation for poro-elastic mediums. Testing of model parameters and variables has improved the root mean square error (RMSE) by up to 63.7% when studying the full signal, and up to 62.6% for the rebar echo locations. These improvements signify better curve fitting between simulated and measured responses, which lead to increased accuracy in the model parameter outputs.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014265
Subject Headings: Reinforced concrete, Reinforcing bars--Corrosion, Ultrasonic testing
Format: Document (PDF)

Title: BACKGROUND STRUCTURE FUNCTIONS, A BASIS TO REDUCE ACOUSTIC POWER REQUIREMENTS AND IMPROVE IMAGES.
Creator: Kobold, Michael C., Beaujean, Pierre-Philippe J., Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Background Structure Functions (BSFs) are wavefront distortion metrics, functions of Sound Speed Profiles (SSPs) that are functions of depth. Use of these BSFs is a synthesis form of Matched Field Processing (MFP) that detects signals that are otherwise lost to receivers. Underwater Acoustics (UWA) can use these models to forecast communication and imaging performance and to reduce power radiated into the sea. This reduction of Transmission Loss (TL) occurs because the commercial wavefront...
Show moreBackground Structure Functions (BSFs) are wavefront distortion metrics, functions of Sound Speed Profiles (SSPs) that are functions of depth. Use of these BSFs is a synthesis form of Matched Field Processing (MFP) that detects signals that are otherwise lost to receivers. Underwater Acoustics (UWA) can use these models to forecast communication and imaging performance and to reduce power radiated into the sea. This reduction of Transmission Loss (TL) occurs because the commercial wavefront control has an input format that accepts BSFs. The BSF plots represent the purely statistical distortion for communications and remote sensing. Another source of TL reduction comes from the enclosed BSF-based phase and phase variance forecasting that protects equalizers from losing phase-lock. Protecting the equalizers protects the Signal To Noise (SNR) ratios. This dissertation derives the UWA version of these metrics and applies them to the following locations of our SSPs: The BSFs use measured, corrected, and verified SSP groups for 132 different locations in the Atlantic Ocean and the Gulf of Mexico from a Navy Ocean Atlas, as well as 64 SSPs in two areas in the littorals, Port Everglades, and Saint Andrew Bay, plus tidal variations. Since BSFs digitize the propagation into one or more segments, our purely statistical phase screen model uses only 3 or 4 degrees of freedom (DOFs) per segment compared to many dozen DOFs for conventional structure functions. The BSFs forecast communications and imaging performance, including range, in locations where acoustic measurements are not available, but SSPs are. A separate algorithm forecasts Gouy phase anomalies from background SSPs, which otherwise requires a priori knowledge of anomaly location and use of Catastrophe theory due to ray theory failure at focuses. Avoiding these anomalies and loss of Phase-Locked Loops (PLLs) also helps maintain SNR and lowers transmission power requirements. Combining with phase parameters and performance forecasts improves UWA propagation efficiency using the background (SSPs). In a spatial version of delay equalization, BSF analysis also produces the enclosed Shear Distortion Ratios (SDRs) for the same locations mentioned above, to allow optimum selection of image enhancement algorithms that mitigate image shear distortion.
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Date Issued: 2024
PURL: http://purl.flvc.org/fau/fd/FA00014395
Subject Headings: Underwater acoustics, Sound--Speed, Ocean engineering
Format: Document (PDF)

Title: Location-Aware Source Routing Protocol for Underwater Acoustic Networks of AUVs.
Creator: Carlson, Edward A., Beaujean, Pierre-Philippe J., An, Edgar
Date Issued: 2012
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1155_2012_765924_1629746277
Format: Citation

Title: Wavelet de-noising applied to vibrational envelope analysis methods.
Creator: Bertot, Edward Max, Khoshgoftaar, Taghi M., Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: In the field of machine prognostics, vibration analysis is a proven method for detecting and diagnosing bearing faults in rotating machines. One popular method for interpreting vibration signals is envelope demodulation, which allows a technician to clearly identify an impulsive fault source and its severity. However incipient faults -faults in early stages - are masked by in-band noise, which can make the associated impulses difficult to detect and interpret. In this thesis, Wavelet De...
Show moreIn the field of machine prognostics, vibration analysis is a proven method for detecting and diagnosing bearing faults in rotating machines. One popular method for interpreting vibration signals is envelope demodulation, which allows a technician to clearly identify an impulsive fault source and its severity. However incipient faults -faults in early stages - are masked by in-band noise, which can make the associated impulses difficult to detect and interpret. In this thesis, Wavelet De-Noising (WDN) is implemented after envelope-demodulation to improve accuracy of bearing fault diagnostics. This contrasts the typical approach of de-noising as a preprocessing step. When manually measuring time-domain impulse amplitudes, the algorithm shows varying improvements in Signal-to-Noise Ratio (SNR) relative to background vibrational noise. A frequency-domain measure of SNR agrees with this result.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004080, http://purl.flvc.org/fau/fd/FA00004080
Subject Headings: Fluid dynamics, Signal processing, Structural dynamics, Wavelet (Mathematics)
Format: Document (PDF)

Title: The Comprehensive Evaluation of Performance and Environmental Influence on MPSK Modulated High-Speed Acoustic Communications in Shallow Water.
Creator: Proteau, Joshua C., Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A daily study spanning a month of the shallow water acoustic channel was conducted to estimate the environmental influence on performance of an underwater acoustic communications system. An automated acoustic modem transmitted phase-coherent modulated sequences of identical data with 186 dB re IpPa source level, at coded rates from 4000 to 16000 bits/s with 4 or 8 kHz symbol bandwidth, three times daily for a month. A 64 channel Mills-Cross receiver array was used with horizontal and vertical...
Show moreA daily study spanning a month of the shallow water acoustic channel was conducted to estimate the environmental influence on performance of an underwater acoustic communications system. An automated acoustic modem transmitted phase-coherent modulated sequences of identical data with 186 dB re IpPa source level, at coded rates from 4000 to 16000 bits/s with 4 or 8 kHz symbol bandwidth, three times daily for a month. A 64 channel Mills-Cross receiver array was used with horizontal and vertical beams each containing 32 and 33 elements respectively, spaced 0.03 meters apart, with a sampling frequency of 72 kHz. Source and receiver were deployed at depths of 20 meters respectively, with a 720 meter separation range. Environmental measurements of wind velocity and direction, surface wave activity, current and sound velocity profiles, and tidal measurements were performed. Results demonstrate reliable achievement of high data-rate shallow water acoustic communications using phase-coherent modulation techniques.
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Date Issued: 2006
PURL: http://purl.flvc.org/fau/fd/FA00012541
Subject Headings: Underwater acoustics--Measurement, Artificial satellites in telecommunication, Underwater acoustic telemetry, Signal processing--Digital techniques
Format: Document (PDF)

Title: Small Anodic Polarization as a Mean to Modestly Accelerate Rebar Corrosion.
Creator: da Silveira, Gabrielle Pimentel, Presuel-Moreno, Francisco, Pierre-Philippe, Beaujean, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The study of non-invasive techniques to analyze the propagation of corrosion in steel reinforced concrete structures proves to be a great alternative to better understanding the corrosive process of rebar and increasing its useful life. The study presented in this document examines the evolution of steel reinforced concrete corrosion over time by applying a small anodic current over four samples, one with a single rebar (16X) and three with three rebars. The rebars were interconnected to...
Show moreThe study of non-invasive techniques to analyze the propagation of corrosion in steel reinforced concrete structures proves to be a great alternative to better understanding the corrosive process of rebar and increasing its useful life. The study presented in this document examines the evolution of steel reinforced concrete corrosion over time by applying a small anodic current over four samples, one with a single rebar (16X) and three with three rebars. The rebars were interconnected to apply the anodic current and accelerate their corrosion. Galvanostatic Pulse (GP) was used. This method applies a constant current pulse to the rebar for 150 seconds while monitoring the potential of the rebars. Each rebar's corrosion current was assessed using GP measurements when no anodic current was applied, and the rebars were disconnected. Sample 16X additionally underwent ultrasonic acoustic analysis by collecting the surface and rebar echo response with a transducer and modeling the sound propagation for poroelastic media with an adapted version of the novel Biot-Stoll method.
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Date Issued: 2024
PURL: http://purl.flvc.org/fau/fd/FA00014491
Subject Headings: Reinforced concrete--Corrosion, Reinforced concrete--Analysis, Nondestructive testing
Format: Document (PDF)

Title: Task Allocation and Path Planning for Collaborative Autonomous Underwater Vehicles Operating through an Underwater Acoustic Network.
Creator: Deng, Yueyue, Beaujean, Pierre-Philippe J., An, Edgar, Carlson, Edward
Date Issued: 2013
PURL: http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1155_2013_483095_1629813605
Format: Citation

FAU Theses and Dissertations (28)	+ -
FAU College Collections (7)	+ -

Underwater acoustic telemetry (8)	+ -
Adaptive signal processing (7)	+ -
Underwater acoustics--Measurement (5)	+ -
Acoustical engineering (3)	+ -
Marine sediments--Acoustic properties (3)	+ -

Underwater acoustics (3)	+ -
MIMO systems (2)	+ -
Reinforced concrete (2)	+ -
Reinforcing bars--Corrosion (2)	+ -
Remote submersibles (2)	+ -
Seawater--Acoustic properties (2)	+ -
Signal processing (2)	+ -
Signal processing--Digital techniques (2)	+ -
Sonar (2)	+ -
Underwater acoustics -- Evaluation (2)	+ -
Underwater acoustics--Instruments (2)	+ -
Underwater acoustics--Mathematical models (2)	+ -
Underwater navigation (2)	+ -
Wave-motion, Theory of. (2)	+ -
Wireless communication systems (2)	+ -
Acoustic surface waves. (1)	+ -
Acoustics (1)	+ -
Adaptive signal processing. (1)	+ -
Animal communication. (1)	+ -
Artificial satellites in telecommunication (1)	+ -
Autonomous underwater vehicles (1)	+ -
Bioacoustics. (1)	+ -
Computer integrated manufacturing systems (1)	+ -
Deep-sea sounding (1)	+ -
Electromagnetic waves--Scattering (1)	+ -

Electronic Thesis or Dissertation (28)	+ -
article (7)	+ -

Beaujean, Pierre-Philippe (28)	+ -
Florida Atlantic University (28)	+ -
College of Engineering and Computer Science (19)	+ -
Department of Ocean and Mechanical Engineering (18)	+ -
Beaujean, Pierre-Philippe J. (6)	+ -

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