Micropulsation data recorded at Palo Alto, California during 1963-4 and Ralston, Alberta during 1967 have been used to study "Intervals of pulsations of diminishing period" (IPDP). IPDP's are found to be generated in the dusk-midnight quadrant of the magnetosphere at an equatorial distance of about 6 earth radii. An intensive study of the Ralston data reveals that IPDP's occur during the expansive phase of magnetospheric substorms. It is proposed that IPDP's are generated by a cyclotron instability between energetic protons and left-hand ion cyclotron waves. Their main characteristics are determined by the perturbations of the dusk-midnight sector of the magnetosphere by magnetospheric substorms. One of the main disturbances in that region is a slow decrease and then sudden increase in the magnetic field corresponding to the buildup and decay of a partial ring current. IPDP's show an increase in midfrequency due to the change in the cyclotron instability frequency produced by the increasing magnetic field. This theory is tested by a comparison of frequency increase of IPDP's observed at Ralston and magnetic field increase in the magnetosphere observed by the ATS-1 satellite. Other conditions necessary for IPDP generation are then discussed. It is shown that different combinations of these conditions result in the generation of hm emissions and band type micropulsations. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This thesis investigated the use of a static acoustic data logger known as a Cetacean and Porpoise Detection (C-POD) device for monitoring two species of dolphins that occur in Mossel Bay, South Africa: the Indo-Pacific bottlenose dolphin, Tursiops aduncus, and the Indian Ocean humpback dolphin, Sousa plumbea. These two species have a near shore distribution which brings them into frequent contact with human activities such as boating, fishing, desalination plants and the onshore component of gas extraction facilities which can potentially affect their behaviour and populations dynamics. Although both species are relatively well studied within South Africa in terms of biology and abundance, this has been limited to the KwaZulu-Natal coast and Algoa Bay with little information available for areas west of Algoa Bay, and almost no information available locally on their acoustic behaviour. This study aimed to: 1) calculate the detection range and effective detection radius (EDR) of C-PODs for T. aduncus and S. plumbea taking into account environmental and group parameters that may affect these and 2) distinguish T. aduncus from S. plumbea based on temporal variation in specific echolocation click parameters. Field work took place in Mossel Bay from a land-based platform during the period May 2013 to August 2014. A surveyor‟s theodolite was used to collect positional data on dolphins and behavioural information was collected through visual observations. A C-POD was deployed near the land based site and serviced and downloaded on a monthly basis for the same survey period. Visual detections were matched to acoustic detections (echolocation clicks) made within a 60 sec and 30 sec time window. Data were analysed using the software programme R. General Estimating Equations (GEE) were used to 1) model the detection probability and EDR of a C-POD for both species during both time windows; 2) model differences between the two species for seven click parameters produced by the C-POD. The impact of background noise on C-POD detections was also assessed. As cetaceans are not the only form of sound in a marine environment distinguishing dolphin clicks from all other noise sources can be a challenge. Sources of background noise include clicking shrimp, movement of sediment, boat traffic and chorusing by reef fish and crustaceans during reproductive or territorial displays and storms which can either mask the clicks produced by dolphins or fill up the memory card. Data collected from two different deployment locations at different depths were subsequently compared after significant ix interference from other noise source was detected at the first deployment location. Mean number of detected dolphin clicks after filtering increased from 6463.33 to 97820 clicks per deployment and mean number of minutes in which detections were recorded increased from 0.23 min to 2.79 min per deployment. Average detection probability for bottlenose dolphins was 0.357 (95% CI: 0.352 - 0.363) for the 60 sec window and 0.257 (95% CI: 0.253 - 0.262) for the 30 second window. For humpback dolphins the average detection probability was 0.084 (95% CI: 0.082 - 0.087) for the 60 sec window, and 0.043 (95% CI: 0.042 - 0.044) for the 30 sec window. EDR for bottlenose dolphins was 1161.38 mm (95% CI: 1150.14m – 1172.62 m) for the 60 sec window and 1035.761 m (95% CI: 1024.89 m – 1046. 64 m) for the 30 sec window. EDR for humpback dolphins was 765.25m (95% CI: 755.64 m – 774.85 m) for the 60 sec window and 751.00 m (95% CI: 741. 40 m – 760. 60 m) for the 30 sec window. Detection probability and EDR were higher for bottlenose dolphins than humpback dolphins over both time windows. For both species, during both windows, detection probability was significantly influenced by group size (p < 0.05). Four out of the seven parameters produced by the C-POD yielded significant pairwise differences (p < 0.05) between the species. Average inter-click interval was the only co-variable that was significant in the GEE model. The average ICI for bottlenose dolphins was 55.91 ms (95% CI: 51.23 – 60.60) whilst the average ICI for humpback dolphins was longer at 119.76 ms (95% CI: 119.76 – 174.00). The interaction between average ICI and modal frequency was also significant (p < 0.05) indicating that a combination of co-variables might be required in order to differentiate between the two species. Despite the small sample size and the challenges associated with acoustic studies in a noisy marine environment this study provided valuable information regarding the use of static acoustic data loggers such as C-POD in South Africa. As newer versions of C-POD are frequently introduced many of the challenges encountered in this study will be minimized. / Dissertation (MSc)--University of Pretoria, 2016. / Zoology and Entomology / Unrestricted

En esta tesis se tratan diferentes aspectos de la acústica presente en un telescopio submarino de neutrinos, principalmente en dos vertientes: en el sistema de posicionamiento acústico utilizado para la monitorización de las posiciones de los módulos ópticos presentes a lo largo del detector, así como en sistemas para detección acústica de neutrinos, técnica que actualmente está en fase de estudio. Todos los estudios realizados están enmarcados dentro de dos colaboraciones europeas para el diseño, construcción y operación de telescopios submarinos de neutrinos: Antares (en fase de operación) y KM3NET (en fase de diseño). Objetivos. Los objetivos de este trabajo pueden resumirse en los siguientes aspectos: - Estudios y análisis del sistema de posicionamiento acústico de Antares. Desarrollo del software para la para la automatización del procesado de los datos de dicho sistema e incorporación de los resultados en la base de datos del experimento. Análisis de los datos proporcionados por dicho sistema con el fin de validar su correcto funcionamiento. - Diseño y desarrollo del sistema de posicionamiento acústico para KM3NeT, telescopio unas 20 veces más grande que Antares. - Estudios para la evaluación de la generación acústica paramétrica para el desarrollo de un calibrador compacto capaz de generar señales tipo neutrino útiles en sistemas de detección acústica. Elementos de la metodología a destacar. Cabe destacar aquí que el trabajo se ha desarrollado en el marco de dos colaboraciones internacionales: ANTARES y KM3NeT, financiados con fondos europeos y nacionales. Por su contexto y el carácter de las actividades realizadas ha sido necesaria la formación en distintos campos: telescopios de neutrinos y astropartículas, pero también en otras áreas como la acústica submarina. Además, se ha desarrollado diversas capacidades y destrezas en diversos ámbitos: en instrumentación, en aplicaciones informáticas, en análisis de datos, etc. Más concretamente, se ha trabajado en aplicaciones informáticas para los desarrollos y análisis en ANTARES. / Bou Cabo, M. (2011). Acoustics for underwater neutrino telescopes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10989 / Palancia

abstract: Acoustic emission (AE) signals have been widely employed for tracking material properties and structural characteristics. In this study, the aim is to analyze the AE signals gathered during a scanning probe lithography process to classify the known microstructure types and discover unknown surface microstructures/anomalies. To achieve this, a Hidden Markov Model is developed to consider the temporal dependency of the high-resolution AE data. Furthermore, the posterior classification probability and the negative likelihood score for microstructure classification and discovery are computed. Subsequently, a diagnostic procedure to identify the dominant AE frequencies that were used to track the microstructural characteristics is presented. In addition, machine learning methods such as KNN, Naive Bayes, and Logistic Regression classifiers are applied. Finally, the proposed approach applied to identify the surface microstructures of additively manufactured Ti-6Al-4V and show that it not only achieved a high classification accuracy (e.g., more than 90\%) but also correctly identified the microstructural anomalies that may be subjected to further investigation to discover new material phases/properties. / Dissertation/Thesis / Masters Thesis Statistics 2020

1) Test the accuracy of the Welch Allyn Microtympanometer against standard tympanometry. 2) Correlate preoperative clinical findings with: • Microtympanometry • Standard tympanometry 3) Assess influence of induction by gas anaesthesia on: • Post-induction microtympanometry • Intraoperative myringotomy findings 4) Assess the practicality of using the Welch Allyn Microtympanometer as a screening tool in Pre-School audiological testing.

Thesis. 1976. Ph.D.--Massachusetts Institute of Technology. Dept. of Psychology. / Microfiche copy available in Archives and Humanities. / Bibliography: leaves 45-49. / by Larry M. Leibler. / Ph.D.

Indiana University-Purdue University Indianapolis (IUPUI) / This research focuses on the detection of arterial blockage due to LDL (low density lipoprotein). Arterial blockages are related to two kinds of fats LDL and the HDL. HDL being the good fat, the patient does not have to undergo the biopsy, while in case of LDL, biopsy should be performed. Issues associated with invasive approaches raise safety concerns for patients such as infection, longer operation durations, longer recovery time etc. This research focuses on a noninvasive imaging technique to detect the kind of block age. Photo acoustic approach was investigated in order to simulate human tissues leading to medical diagnosis and treatment. Photo acoustic imaging involves production of an image on absorption of laser pulses. The laser pulses are further scattered and absorbed producing heat. The goals of the study were to categorize the type of the tissue materials based on the output temperature distribution via IR sensors and reflected acoustic waves via acoustic pressure sensors. The reflected acoustic wave and IR thermal distribution may be applied towards arterial blockages to differentiate the different types of tissue layers. The simulation results should have implications towards the future implementation of the practical devices and system. Parameters including energy levels, tissue thicknesses, frequencies, penetration depth, and the densities of the LDL/HDL fat materials were considered. Various energy pulses; 1j, 3j, and 5j were considered as input sources to the tissue materials (single or multi layers). The simulated layers considered in the study were the skin, bone, blood, and fat cells. The temperature and acoustic pressure response over the various layers were analyzed for the detection of blockages. The ndings of the temperature and acoustic pressure ranges can be detected by MEMS/NEMS (Micro electro mechanical systems/ nano electro mechanical systems) sensors, such as IR and Piezoelectric devices. Bioheat and acoustic wave equations were solved simultaneously using COMSOL software for multiple layers. The proper boundary conditions were provided in the solutions of these equations. The scattering and transmission acoustic wave, and the temperature distributions, may be used as guide to the integrated sensor system design for future consideration. The simulation was performed in four stages: (1) Single layer and multiple layers at a given frequency and energy level (2) Multiple layers at a given frequency for different energy levels (3) Multiple layers at a given energy level for different frequency and (4) Multiple layers at a given frequency and energy levels with different size tissues. The simulation results showed that a range of acoustic pressure between 240 and 260 need to be detected, with a di erential temperature distribution in kelvin range. Power pulses of 10MPa showed a temperature change of 175, which is believed to be within the exible substrate sensing devices that may be used for the practical model of this research. The thesis covers a proposed system for the practical model following the simulation results received in this study.

No description available.

The term soundscape, used for the first time at the end of 1970s, refers to the sum of the sounds that can be heard and perceived by people in a specific environment. The concept of soundscape has recently received attention in planning and design disciplines. Recent studies on soundscape have shown that the acoustic environment plays an important role for the comfort of site users. Hence, this research investigates how objective measurement of soundscape might be different from subjective perceptions of users in the Mississippi State University Campus as a public open space due to demographic and climatic variations. The public open spaces studied in the Mississippi State University Campus include four locations: the Mitchell Memorial Library, the Colvard Student Union, the Bell Island, and the Sanderson Center. These locations were evaluated through objective measurement, and subjective evaluation.

With existing numerical models for fluid particle systems in CHEM, the acoustic-particle interactions associated with two-phase dilute dispersed flow can be captured and the particle model can be validated using experimental and analytical data and verified using numerical techniques. The experimental and analytical data come from Zink and Delsasso and provides data for particles of diameters 5 to 15 microns for frequencies between 500Hz to 13600Hz. In the particle number density measurements by Zink and Delsasso there was a 10% estimated error range. Using the fourth order skew symmetric flux in CHEM and the built in Eulerian and Lagrangian particle models, the sound wave dissipation was captured and found to be within the margin of error. Two additional tests were conducted to measure the effect of nonlinear acoustics and increased bulk density on the dissipation. Nonlinear effects showed no significant effect and the linear increase in bulk density showed a linear increase in dissipation.