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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

ANALYSIS OF ARIAS INTENSITY OF EARTHQUAKE DATA USING SUPPORT VECTOR MACHINE

Adhikari, Nation 01 August 2022 (has links)
In this thesis, a support vector machine (SVM) is used to develop a model to predict Arias Intensity. Arias Intensity is a measure of the strength of ground motions that considers both the amplitude and the duration of ground motions. In this research, a subset of the database from the “Next Generation and the duration of Ground-Motion Attenuation Models” project was used as the training data. The data includes 3525 ground motion records from 175 earthquakes. This research provides the assessment of historical earthquakes using arias intensity data. Support vector machine uses a Kernel function to transform the data into a high dimensional space where relationships between the variables can be efficiently described using simpler models. In this research, after testing several kernel functions, a Gaussian Kernel was selected for the predictive model. The resulting model uses magnitude, epicentral distance, and the shear wave velocity as the predictor of Arias Intensity.
102

Light Emission From Rare Earth-Doped Silicon Oxide Films Deposited By ECR-PECVD

Li, Jing January 2008 (has links)
<p>Silicon oxide films (oxygen-rich or silicon-rich) doped with various rare-earth (RE) [cerium (Ce), terbium (Tb), europium (Eu) and erbium (Er)] elements have been by deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD). The successful in-situ incorporation of high concentrations of RE elements has been confirmed by Rutherford backscattering spectrometry (RBS), and the optical properties of the films were analyzed by Photoluminescence (PL) spectroscopy.</p><p> Ce, Tb, Eu and Er related emission was observed from the films with corresponding doping and was found to be sensitive to RE concentration, the presence of Si nanoclusters (Si-ncs) and annealing induced structural evolution. The significant enhancement of Ce^3 + emission in Ce-doped oxygen-rich films under annealing in flowing N2 at 1200 °C was found to be related to the formation of cerium silicate whose presence was confirmed by Fourier transform infra-red (FTIR) spectra and high-resolution transmission electron microscopy (HR-TEM) images. The observation of intense Tb^3+ emission from Tb-doped oxygen-rich films under nonresonant excitation revealed the presence of indirect excitation processes. The organic ligands introduced from the Tb(tmhd)3 precursor during deposition was considered as the possible sensitizer. The presence of Si-ncs in Ce or Eu-doped silicon-rich films resulted in the quenching of both RE and Si-ncs PL, while in Tb or Er-doped silicon-rich films the coupling between Si-nes and RE ions can excite RE-related emission efficiently. The formation of Si-ncs with sizes of 2-3 nm in Tb-doped silicon-rich films under annealing in flowing N2 at 1100 and 1200 °C was revealed by HR-TEM images.</p> / Thesis / Master of Applied Science (MASc)
103

The Effect of Hydrotherapy on Recovery and Performance During High Intensity Exercise

Stacey, Douglas 06 1900 (has links)
Athletes use a wide range of interventions to promote recovery from strenuous exercise, but few data are available regarding the efficacy of such practices. OBJECTIVE: To examine the effectiveness of commonly used interventions [Rest, light exercise (AR), contrast therapy (CT) and cryotherapy (CR)] during recovery between bouts of intense exercise. We tested the hypothesis that hydrotherapy interventions (CT and CR) would induce favorable physiological and/or psychological alterations such that performance would be improved versus AR and Rest. METHODS: In Study I, 12 active men (25-35 yrs; VO2peak = 46±3 ml·kg-1·min-1; mean±SD) performed 5 consecutive days of HI exercise (4-6 bouts x 30 sec 'all out' Wingate Tests, with 4-min recovery, each day). After each training session, subjects either rested for 20 min (CON, n=6) or completed a CT protocol (n=6) that consisted of alternating cold (10°C) and hot (40°C) tubs using a 4x2:3 min ratio. Performance measures [Peak (Wmax) and mean (Wmean) power, VO2peak, and a 250 kJ Time Trial (TT)] were assessed before and after the HIT. In Study II, 9 active men (29±6 yr, VO2peak = 44±8 ml·kg-1·min-1) performed 3 exercise trials separated by 1 wk. Each trial consisted of 3 x 50 KJ time trials(~100-120%VO2peak) with a different 20-min recovery period [CON, AR (cycling@ SOW) or CR (cold tub@ 10°C)] between rides each week. Venous blood samples were obtained after each recovery period, and analyzed for lactate, interleukin-6, neutrophils, and lymphocytes. Questionnaires designed to assess exercise preparedness were also completed daily in both studies. RESULTS: In Study I, Wmax and TT performance improved after 5 d of HI exercise (time effect, P<0.05), but there were no differences between groups (Wmax-CT: Post: 1310±45 vs Pre: 1215±86; CON: Post: 1343±54 vs Pre: 1220±74 W: TT-CT: Post: 15.8±0.6 vs Pre: 16.7±0.7; Rest: Post: 18.1±1.0 vs Pre: 18.8±1.2 min, means±SEM). In Study II, TT performance averaged 118±10 sec for bout 1 and was 8% and 14% slower during bouts 2 (128±11 sec) and 3 (134±11 sec), respectively, with no difference between treatments (Time effect, P≤0.05). Blood lactate was lower after AR compared to CR and Rest, and neutrophils and lymphocytes were higher and lower respectively (P≤0.05), after CR (8.7±1.3 and 1.4±0.2 x 109cells/L) versus AR (7.1±1.0 and 1.6±0.1) and Rest (6.7±0.7 and 1.6±0.1). With respect to the psychological measurements, the CT and CR groups in both studies reported feeling more revitalized after each treatment session and greater preparedness for subsequent exercise (Treatment effect, P≤.05). CONCLUSIONS: Exercise performance during repeated bouts of intense cycling was not influenced by the type of recovery intervention employed, either during a single session or over the course of a 5 d training session. CR caused greater perturbations in blood immune markers and most notably, hydrotherapy interventions created the perception that subjects were better prepared for subsequent exercise. / Thesis / Master of Science (MS)
104

Teachers' stages of concern about a school-wide educational reform

Aneke, Norbert O. 06 June 2008 (has links)
This study sought to verify the stages of concern theory according to Hall, Wallace, and Dossette (1973), using a school-wide educational reform. Furthermore, changes in teachers' concern profiles as a function of education levels, teaching areas, hours of reform-related training, and adoption-proneness were studied. In particular, teachers' concern profiles about implementing the High Schools That Work (HSTW) reform in Virginia were studied. One thousand two hundred and seven teachers in 19 sites implementing the HSTW reform in Virginia participated in the study. Of the purposive sample of 1207 teachers to whom study questionnaires were forwarded by mail, 674 responded and returned their questionnaires. The questionnaire consisted of three sections: the Stages of Concern section (Hall, Wallace, & Dossette, 1973), the Adoption-proneness section (Oscarson, 1977), and the demographic information section. Data were analyzed, using descriptive statistics and multivariate analysis of variance procedures (α = .05). Results revealed that teachers with no HSTW reform experience (N = 131) had highest concern at the personal stage, followed by teachers in their first year of experience (N = 207), and teachers in their second year of experience (N = 230). Teachers in their third year of experience (N = 70) revealed the least concern at the personal stage. There was significant change in teachers’ concern associated with amount of experience F(21, 1880) = 12.32, p = .00 (p < .05). Teachers with more experience had peak concerns at the consequences and collaboration stages while teachers with less experience had peak concern at the personal stage. Results agreed with the theory which states that as experience in reform use increases, concern moves from informational and personal stages to consequences and collaboration stages. Change in teachers’ concern as a function of education level was significant F(28, 2502) = 2.09, p = .001 (p < .05). Teachers with doctoral degrees, followed by those with 30 credit hours above the master's degree, revealed more collaboration concern than teachers with associate, bachelor’s, and master's degrees. Concern change due to teaching area was not significant F(7, 630) = 1.81, p = .08 (p > .05). The concern profiles of vocational and academic teachers were parallel and coincident, but not level. Teachers’ concern change as a function of hours of related training was significant F(14, 1256) = 12.12, p = .00 (p< .05). Teachers with no reform-related training had peak concern at the personal stage while those with more than 15 hours of training had peak concerns at the collaboration and consequences stages. Teachers who had 15 hours or less of training had lower personal concern than those who had no training, but higher than those who had more than 15 hours of training. Teachers’ concern as a function of adoption-proneness was significant F(7, 630) = 14.53, p = .00 (p < .05). While all the teachers revealed similar informational, personal, and management concerns, teachers who were more adoption-prone had more intense concern at the consequences and collaboration stages. / Ph. D.
105

Turbulence Modulation of Polydisperse Particles in a Square Particle-Laden Jet: Numerical Investigation

Gray, Sandria Lutrica 06 June 2012 (has links)
The purpose of this study is to numerically investigate the turbulence modulation of polydisperse particles in a square particle-laden jet. Turbulence modulation describes the effects of fluctuating velocity and intensity when the particles and continuous fluid interact in a turbulent flow field. The rate at which turbulence modulation is altered is dependent upon parameters such as particle size, mass loading, Stokes number, coupling, volume fraction and mechanisms of turbulence modulation. This study modifies the analytical model developed by Yarin and Hetsroni (1993) to account for the transitional drag regime for coarse polydisperse particles. The particles under study are dilute, inert and spherical, with relatively high Stokes numbers, and classified as having two-way coupling with the fluid. The new analytical model is compared to numerical results using the Computational Fluid Dynamics (CFD) software FLUENT (ANSYS, Inc.). The turbulence model employed is the standard k-ε model. This study will analyze the effects of varying mass content and particle ratios to investigate how turbulence modulation is influenced. The new model and the CFD results show good agreement in the cases where the mass contents of each particle size are equal. This study will also look into the effects of polydispersion, and the concentration distribution, for indoor air applications. It was found that, in certain cases, the monodisperse assumption slightly over-predicts the concentration distribution in the enclosed region. / Master of Science
106

A Photoelastic Investigation into the Effects of Cracks and Boundary Conditions on Stress Intensity Factors in Bonded Specimens

Gloss, Kevin T. 15 May 2000 (has links)
An investigation into the influence of cracks in bonded specimens is conducted. Photoelastic specimens containing a bondline are subjected to a constant displacement boundary condition created by bonded end grips. Specimens containing various crack orientations are analyzed to determine stress intensity factors at the induced crack tips. Specimens containing interface and sub-interface cracks were investigated. Two global geometries were used in this investigation, square and rectangular. The constant displacement boundary condition was induced on the specimen through dead weights hung from bonded aluminum end grips. Stress intensity factors were determined using photoelastic techniques. The stress intensity factors were examined to determine trends in the results as a function of changes in geometry. The effects of the induced boundary condition, the specimen geometry, and the bondline were investigated. The results from this investigation were compared to known solutions with a similar specimen geometry. These tests exhibited influences from the bondline, the boundary conditions, and the specimen geometry. The bondline tended to decrease the stress intensity factor for specimens with small crack lengths and tended to increase the stress intensity factor for specimens containing long crack lengths. As the crack length increased so too did the stress intensity factor. A reduction in the bondline to crack distance with sub-interface crack specimens caused a reduction in the stress intensity factor. A reduction in the global height of the specimen caused a reduction in the stress intensity factor also. The results from this investigation will aid in the understanding of the influence of interface and sub-interface cracks in bonded specimens. / Master of Science
107

Source studies over a wide range in earthquake magnitude

Taylor, David W. January 1988 (has links)
The concept of similarity (that earthquake source parameters obey scaling relations) and the empirical linear relation between magnitude and the log₁₀ of the number of events (the Gutenberg-Richter relation) describe well the behavior and recurrence of many earthquake data sets. The universality of these relations are tested herein using a suite of earthquakes from the southeast comer of Hokkaido Island, Japan. Within this active seismic region, over 11,100 events ranging in magnitude from 0 to 7.1 were cataloged by the Hokkaido University network in the period 1976-1986 with epicentral distances of less than 50 km from the Carnegie broadband station KMU. Two subsets of the events are examined herein: crustal earthquakes, those with locations shallower than 45 km and above the top of the subducting Pacific plate, and subduction earthquakes, those with locations below 60 km within the subducting plate. The frequency of occurrence versus magnitude relations for both the crustal and subduction events are nonlinear with a definite decrease in the number of detected events for lower magnitudes, but the subduction events have proportionally more large earthquakes and fewer small earthquakes than the crustal data suite. A completeness analysis indicates that the catalogs are complete to less than magnitude 2, which is clearly in the nonlinear region, suggesting that the observed curvature of the frequency-magnitude curves is not due to incompleteness of the catalogs. Hence, a single, linear Gutenberg-Richter relation is inadequate for describing the frequency of occurrence of these events. The ratio of the frequency-magnitude curves gives a remarkably linear relation from magnitude 1 to magnitude 5, indicating that in terms of fitting these frequency-magnitude curves to higher order polynomials, the crustal and subduction data sets have identical higher order coefficients, and their curvature difference is caused by only the constant and linear coefficients. A possible cause for the difference in the recurrence relations is the increased lithostatic load with depth. In an attempt to gain insight into the frequency of occurrence characteristics of the data, the seismic energy release of the crustal and subduction regions was calculated as a function of time. Evaluation of the energy release versus time indicates that there was a precursory energy decrease prior to the m<sub>L</sub> = 7.1 event in 1982. Analysis of energy release appears to be a potentially useful and relatively objective technique for studying precursory quiescence. Using data from the Carnegie broadband station KMU, seismic source scaling relations were derived for 21 crustal and 24 subduction events. Using Q-corrected SV and SH amplitude spectra and assuming an average focal mechanism, spectral parameters (zero frequency level and comer frequency) were estimated using the objective technique of Snoke (1987). Cepstral filtering was employed both to remove the effect of multiple arrivals, as well as to increase the objectivity with which parameters were determined. The resulting moment versus magnitude relations indicate a significant change in slope around magnitude 3.5 and moment 2 x 10²⁰ dyne-cm. Brune radii average 0.3 km over the range 10¹⁸ to 10²¹ dyne-cm, and increase from 0.6 to 2 km over the range 10²² to 10²⁵ dyne-cm. Log Brune stress drop was found to be linearly correlated with log moment with a slope of approximately unity below 10²¹ dyne-cm, and highly correlated but with a slightly smaller slope above that point. For lower moments, stress drops increase with moment from 0.035 bar to 10 bar, and for higher moments, stress drops range from 10-822 bar, with most values near 100 bar. These variations of radius and stress drop with moment for moments below 10²¹ dyne-cm is inconsistent with the similarity hypothesis. Stress drop versus moment relations were compared with those from a study for the Matsushiro region, Japan, which is characterized by a shallow, localized crustal seismicity. No significant difference is found between the scaling relations for the crustal earthquakes, subduction earthquakes, and Matsushiro earthquakes taken separately, even though the tectonic stress is expected to be quite different in the three regions. We conclude that the calculated scaling relations are not directly determined by the tectonic stress. / Ph. D.
108

The Implications of Different Types of Diet and Exercise on Human Health

Clayton, BethAnne C 01 July 2016 (has links)
There is need for enhanced prevention and treatment methods to combat sedentary lifestyle, obesity, and chronic disease by investigating the impact of specific exercise modalities and dietary factors on human health. The purposes of this study were: 1) to assess self-selected and perceived exercise intensity during High-Intensity Functional Training (HIFT) between males and females and to determine variables that predict self-selected exercise intensity (%VO2max) and/or perceived intensity (RPE) and 2) to investigate the impact of obesity on skeletal muscle metabolism in response to lipid oversupply by analyzing the responses of genes linked with fatty acid oxidation and inflammation in lean and obese subjects. Males and females were recruited to complete a 15min HIFT circuit wearing a metabolic analyzer, reporting RPE during and after the exercise bout. Obese and lean females were recruited to provide skeletal muscle cell biopsies for harvesting cell cultures from which to measure change in gene expression after exposure to a high lipid treatment. The first study results demonstrate that females exercised at a significantly higher self-selected exercise intensity while also reporting a lower RPE (p < 0.05). The second study revealed differential gene expression response and pathway activation related to lipid metabolism and inflammation between the lean and obese. In conclusion, gender plays a significant role in the intensity self-selected and the RPE reported during HIFT, suggesting HIFT may be an optimal home-based modality for female clients. Additionally, the skeletal muscle metabolic and inflammatory gene expression of the lean and obese respond differently to a high fat exposure and may provide further evidence of mechanisms linking obesity to metabolic disease.
109

Three-dimensional broadband intensity probe for measuring acoustical parameters

Miah, Khalid Hossian 19 October 2009 (has links)
Measuring different acoustical properties have been the key in reducing noise and improving the sound quality from various sources. In this report, a broadband (200 Hz – 6.5 kHz) three-dimensional seven-microphone intensity probe system is developed to measure the sound intensity, and total energy density in different acoustical environments. Limitations of most commercial intensity probes in measuring the three-dimensional intensity for a broadband sound field was the main motivation in developing this probe. The finite-difference error and the phase mismatch error which are the two main errors associated with the intensity measurements are addressed in this report. As for the physical design, seven microphones were arranged in a two-concentric arrays with one microphone located at the center of the probe. The outer array is for low-frequencies (200 Hz – 1.0 kHz), and the inner one is for high-frequencies (1.0 kHz – 6.5 kHz). The screw adjustable center microphone is used for the microphone calibration, and as the reference microphone of the probe. The simultaneous calibrations of all the microphones in the probe were done in the anechoic room. Theories for the intensity and the energy densities calculations for the probe were derived from the existing four-microphone probe configuration. Reflection and diffraction effects on the intensity measurements due to the presence of the microphones, and the supporting structures were also investigated in this report. Directivity patterns of the calculated intensity showed the omnidirectional nature of the probe. The intensity, and total energy density were calculated and compared with the ideal values in the anechoic room environment. Characterization of sound fields in a reverberant enclosed space, and sound source identification are some applications that were investigated using this probe. Results of different measurements showed effectiveness of the probe as a tool to measure key acoustical properties in many practical environments. / text
110

Use of Phase and Amplitude Gradient Estimation for Acoustic Source Characterization and Localization

Lawrence, Joseph Scott 01 July 2018 (has links)
Energy-based acoustic quantities provide vital information about acoustic fields and the characterization of acoustic sources. Recently, the phase and amplitude gradient estimator (PAGE) method has been developed to reduce error and extend bandwidth of energy-based quantity estimates. To inform uses and applications of the method, analytical and experimental characterizations of the method are presented. Analytical PAGE method bias errors are compared with those of traditional estimation for two- and three-microphone one-dimensional probes. For a monopole field when phase unwrapping is possible, zero bias error is achieved for active intensity using three-microphone PAGE and for specific acoustic impedance using two-microphone PAGE. A method for higher-order estimation in reactive fields is developed, and it is shown that a higher-order traditional method outperforms higher-order PAGE for reactive intensity in a standing wave field. Extending the applications of PAGE, the unwrapped phase gradient is used to develop a method for directional sensing with improved bandwidth and arbitrary array response.

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