In sea turtles, body condition can be evaluated through subjective body condition scoring (BCS), calculating body condition index (BCI), and clinical blood parameters. The goal of this study was to analyze ultrasonography of subcutaneous fat depth as a method to estimate body condition in 10 green and 8 loggerhead sea turtle carcasses using two types of portable ultrasound technologies, the Ibex Evo® and the Renco Lean-Meater®. Despite the general lack of significant correlations between ultrasound-assisted, gross, and histological measurements, the dorsal shoulder and lateral neck were determined to provide the most consistent images of subcutaneous fat. Florida live-captured green turtles were sampled and ultrasound-assisted fat depth measurements were taken at the dorsal shoulder region; however, there were no significant correlations found between fat depth and BCI or blood analytes (PCV, total protein). BCI reference quartiles were created using associations between BCI and BCS to help provide biological context to BCI data and allow for rapid categorization of sea turtle body condition. / Includes bibliography. / Thesis (MS)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

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Heterogeneities in concrete caused by the random distribution of aggregate in the cement-paste matrix lead to strong scattering of ultrasound waves at wavelengths on the order of the aggregate. Use of these high frequencies is necessary to detect damage at an early stage, something that is not possible with conventional ultrasonic methods. The ultrasound energy density in this regime can be described by the diffusion equation. The objective of this research is to develop a quantitative understanding of the effects of additional scattering sources, such as small cracks in the cement-paste matrix, on the parameters of the diffusion equation; these parameters are the diffusion and the dissipation coefficients. Experimentally measured ultrasonic waves are processed using the diffusion theory to determine the diffusivity and the dissipation coefficients as a function of frequency. The samples employed are made of a Portland cement-paste matrix and regular aggregate such as gravel and sand. The results provide a basic understanding of the repeatability and consistency of diffusion measurements, with an emphasis on the nondestructive evaluation of damage in concrete. In addition, a method to describe concrete in the coherent regime is examined. Existing wave propagation models for inhomogeneous materials deal with two-phase mixtures, mostly the matrix-inclusion system such as fiber-reinforced composites. There are, however, numerous examples of multi-phase materials in which more than one phase is suspended in a matrix-phase. This research considers concrete, in which cement paste and aggregates with different sizes and mechanical properties are mixed together. Most of the models for two-phase composites cannot be extended to a multi-phase composite. Among others, the effective medium theory is considered here for two reasons: first, the formalism in this theory can easily be extended to multi-phase cases; second, the theory does not strictly define a specific microstructure between phases, which allows for a simulation of the microstructure in which different inclusions are in contact. The mathematical formulation is presented that yields the formulae for the effective density and the effective bulk and shear moduli. Finally, the calculated wave speeds and attenuations for different materials are compared with experimental results.

Context: Large numbers of bats are killed by collisions with wind turbines and there is at present no accepted method of reducing or preventing this mortality. We designed a system, which detects and records any bats’ activity in and around the surroundings of wind turbines. The system can help to study bats by identifying the species that are present in that particular locality. Objectives: The main objective of this thesis is to design an ultrasound-based IoT system, which detects the bats to prevent them from clashing with wind turbines. The design is based on a study of bats’ behaviors. Methods: The system has been developed using User-Driven Design, UDD, approach. The required functionalities have been embedded into IoT based system. An ultrasonic technology along with other sensors are used. The sensors are intended to activate monitoring during favorable conditions for bat activity. Results: A model of a system has been developed. The model was implemented into a prototype. Recorded bats’ activities are uploaded to a server by employing a suitable app, which informs the user about the activities of bats' various sub-species. Conclusions: A surveillance for bats approaching the wind farms within 80 m has been developed. The monitoring system is activated when the weather conditions are favorable for bat activities.

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Typescript (photocopy). / Digitized by Kansas Correctional Industries

This work is centered on low-frequency and high-frequency multiphysics problems of piezoelectric structures submerged in a quiescent fluid domain for the applications of vibration energy harvesting, biomimetic actuation, and contactless acoustic energy transfer. In the first part of this research, Macro-Fiber Composite (MFC)-based piezoelectric structures are employed for underwater mechanical base excitation and electrical biomimetic actuation in bending mode at low frequencies (the fundamental underwater bending resonance being in the infrasonic frequency range). The MFC technology (fiber-based piezoelectric composites with interdigitated electrodes) exploits the effective 33-mode of piezoelectricity, and strikes a balance between structural deformation and force levels for actuation to use in underwater locomotion, in addition to offering high power density for energy harvesting to enable battery-less aquatic sensors. Following in-air electroelastic composite model development, the fundamental research problem is to establish semi-analytical models that can predict the underwater dynamics of thin MFC cantilevers for different length-to-width aspect ratios. In-air analytical electroelastic dynamics of MFCs is therefore coupled with added mass and nonlinear hydrodynamic damping effects of fluid to describe the underwater electrohydroelastic dynamics in harvesting and actuation. To this end, passive plates of different aspect ratios are tested to extract and explore the repeatability of the inertia and drag coefficients in Morison’s equation. The focus is placed on the first two bending modes in this semi-empirical approach. In particular, electrode segmentation is studied for performance enhancement in the second bending mode. Additionally, nonlinear dependence of the output power density to aspect ratio is characterized theoretically and experimentally in the underwater base excitation problem. In the second part of this work, Ultrasonic Acoustic Energy Transfer via piezoelectric transduction is investigated theoretically and experimentally. Contactless energy transfer using acoustic excitation offers larger distances of power transmission as compared to well-studied inductive method. Various transmitter configurations (e.g. spherical, cylindrical, and focused) are explored for energy transfer to a piezoelectric receiver bar (operating in the longitudinal/thickness mode) that is shunted to a generalized resistive-reactive circuit. Fixed-free and free-free mechanical boundary conditions of the receiver are explored in detail. The resulting multiphysics analytical model framework is compared with finite-element simulations and experiments conducted in fluid (water and oil). Optimal piezoelectric receiver material and electrical loading conditions are sought for performance and bandwidth enhancement.

A method for acquiring and analyzing ultrasonic wavefields to characterize scattering from defects is described. A laser vibrometer and XY scanner are used to record high resolution wavefield data for angle-beam waves propagating in both a defect-free plate and a plate containing crack-like defects emanating from a through-hole. The properties of angle-beam wave propagation are first studied, which include wave generation mechanisms, propagation trajectories, and apparent phase velocities on the measurement surface. Scattering from a defect of interest is then analyzed by subtracting wavefields recorded before and after introduction of the defect. Wavefield subtraction is very sensitive to unavoidable spatial misalignment, which must be corrected prior to subtraction. Two methods for aligning wavefield data sets prior to subtraction are described and their performance is assessed. Several methods for characterizing scattering, including radial energy plots and scattering patterns, are described and used to quantify scattering from the introduced defects. Finally, efficacy of the scattering characterization methods is discussed and recommendations are made for future work.