Background: Multidrug-resistant tuberculosis (MDR-TB) patients receive aminoglycosides as part of their treatment. These drugs are ototoxic, and can cause permanent damage to the cochlea, resulting in a debilitating hearing loss, which has a negative impact on an individual's quality of life. Early detection and management of an ototoxic hearing loss can minimise the impact of the hearing loss on the person's social, emotional, and vocational wellbeing. While patients with MDR-TB are often very ill, it might be ideal to use an objective test that does not require active participation from the patient. In this way, the reliability and validity of the test will not be affected by the patient's state. Distortion product otoacoustic emissions (DPOAEs) at 2f1-f2 are a viable option, as it evaluates cochlear function, specifically the outer hair cells, which are affected first by ototoxic medication. Method: This thesis used a sequential study design aimed to determine the DPOAE stimulus parameters that yield (a) the highest level and the most reliable, sensitive and specific DPOAEs reported in the literature, (b) the highest level and the most reliable DPOAEs in healthy, normally hearing adults, and (c) the most sensitive and specific DPOAEs in participants with MDR-TB patients receiving ototoxic medication. High frequency pure tone audiometry (defined in this thesis as frequencies > 8 kHz) was used as the gold standard. Descriptive statistics, the intraclass correlation coefficient, Pearson's correlation coefficient and mixed model analyses were used to analyse the data. Results: Systematic review: The results of the systematic review indicated an L1/L2 setting of 75/75 dB SPL and f2/f1 value from 1.20 to 1.22 yielded the highest level DPOAEs. The systematic review results for stimulus parameters that yielded the highest test-retest reliability, sensitivity and specificity were inconclusive. Preliminary study with healthy normal hearing participants: The results of the preliminary study in healthy, normal-hearing participants indicated that the highest levels of DPOAEs were elicited with L1/L2 intensity levels of 65/65 and 65/55 dB SPL, and f2/f1 ratios of 1.18, 1.20 and 1.22, as determined by mixed model analyses (p < 0.05). These same stimulus parameters yielded the most reliable DPOAEs in both ears, as determined by intraclass correlation coefficient analysis. Main study with healthy, normal-hearing participants: Descriptive statistics and mixed model analysis showed stimulus intensity levels L1/L2 of 65/55 dB SPL, and f2/f1 ratios of 1.18 and 1.20, elicited the largest DPOAEs. The ratio of 1.20 yielded the largest DPOAEs < 5000 Hz and f2/f1 ratio of 1.18 the largest DPOAEs ≥ 5000 Hz. The second highest DPOAE levels were elicit by L1/L2 = 65/65 dB SPL and f2/f1 = 1.18. The test-retest reliability in this sample was not influenced by changing the stimulus parameters, and DPOAEs were only unreliable at an f2 frequency of 8 000 Hz. Study in participants with MDR-TB: Results in participants with MDR-TB receiving ototoxic medication indicated that the highest levels of DPOAEs were elicited with L1/L2 = 65/55 and an f2/f1 ratio of 1.18 at f2 ≥ 5000 Hz, followed by 65/65 and 1.18. For f2 < 5000 Hz, stimulus intensities of L1/L2 = 65/55 and an f2/f1 ratio of 1.20 yielded the largest DPOAE levels. Relating to sensitivity and specificity, the stimulus parameter combination of 65/55 dB and 1.18 detected the highest number of ears with outer hair cell damage in participants with MDR-TB receiving ototoxic medication. Conclusion: It should be considered to use an f2/f1 ratio of 1.18 for f2 ≥ 5000 Hz and 1.20 for f2 < 5000 Hz when monitoring for ototoxicity, to assist with early identification of outer hair cell damage, in conjunction with high frequency pure tone audiometry. This finding needs to be confirmed in a larger sample of participants with MDR-TB receiving ototoxic medication.

An analytical investigation of dynamic compressor characteristics was conducted with the goal to make fundamental improvements in the modeling of dynamic compressor stage characteristics. It was determined that present state-of-the-art in modeling dynamic compressor stage characteristics is the use of steady-state characteristics derived from flow model calculations, with first-order time lag response functions applied to account for dynamic departures from the steady and quasi-steady performance predictions. This investigation developed a blade frequency response function (FRF) method for describing the dynamic blade response. Once the frequency response function of a blade row has been determined, any time or spatially dependent, non-uniform flow can be applied and the model will predict the dynamic blade response. The first step of this research was to develop FRFs based on first-order lag equations and to test the method using these simple transfer functions. The next step was to develop FRFs based on a dynamic blade lift model for a simple, idealized compressor blade row model. It was found that chord length has a strong influence on the FRF, which is related to the fluid transport time through the blade passage. The final step was to incorporate experimental data obtained from a study of dynamic wake response of an isolated rotor. It was assumed that the wake response was well correlated with the dynamic lift response of a blade row. It was found that aerodynamic loading, distortion strength, and span position all influence the frequency response functions, which differ greatly from simple first-order lag equations. It was determined that a number of FRFs are needed to describe the dynamic blade response accurately. / Master of Science

An experimental investigation of the wake of a low-speed axial-flow compressor rotor was conducted with and without the presence of steady inlet total pressure distortions. The steady three-dimensional rotor inlet flow was obtained by a five-hole pneumatic pressure probe, while the one-dimensional rotor exit data were obtained using a piggyback steady/unsteady total pressure probe in non-nulling mode. Both inlet and exit flow conditions were measured in the stationary frame of reference. Results indicate increases in wake thickness and magnitude of total pressure defect as blade loading increased into the distortion cycle. The wake suction side jet increased in width and magnitude as blade loading increased, which appears to be a response to flow blockage caused by the growing boundary layer on the blades. Based on one-dimensional exit total pressure conditions with respect to the distortion screen, the dynamic response of the intra-blade passage flow does not appear to be a function of blade loading, measurement span, or distortion intensity within the ranges tested. Unsteady one-dimensional rotor exit suction side jet width and magnitude varied a great deal within and outside of the distorted region, and were only moderately correlated to inlet flow conditions. Changes in the unsteady one-dimensional rotor wake width and magnitude were usually in phase with and strongly correlated to changes in the inlet flow conditions. / Master of Science

The interfacial heat transfer coefficient is an important variable regarding the subject of metal castings. The error associated with the experimental temperature data must be dealt with appropriately so that they do not significantly affect the resulting interfacial heat transfer coefficient. The systematic and random errors are addressed using a combination of three-dimensional finite element modeling and the matrix transform method, respectively. Experimentally obtained A356 permanent mold casting data was used to estimate the interfacial heat transfer coefficient corresponding to common industrial mold coatings.

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Nowadays the development of the screen technology is really fast, there are lcd, led, oled screen and many kinds of screens. They all have their own advantages and disadvantages, LCD screen is usually constrained by the size, and the LED screen is usually constrained by the resolution. In this thesis I will introduce a tiled projection screen which combined LED and LCD together. My major work is to develop algorithms which are used to solve three major problems. The first problem is the radial distortion caused by the lens. This problem is different from the usual distortion correction problem, the method used in this thesis is a reverse process of the camera calibration and the key is to simulate the distortion formula. The second problem is the complex brightness condition of the tiled projected image. In the thesis a non-linear edge blending method is applied so the projected images could merge together seamlessly. The third problem is combination of the LED and the LCD without harming the resolution of the whole picture. The result shows that the size and the resolution have been improved greatly. / Thesis / Master of Applied Science (MASc)

An experimental investigation was conducted in a static ground test facility to determine the flow quality of a serpentine inlet duct incorporating active flow control for several simulated flight conditions. The total pressure distortion at the aerodynamic interface plane (AIP) was then used to predict the resulting stability for a compression system. This study was conducted using a model of a compact, low observable, engine inlet duct developed by Lockheed Martin. A flow control technique using air injection through microjets at 1% of the inlet mass flow rate was developed by Lockheed Martin to improve the quality of the flow exiting the inlet duct. Both the inlet duct and the flow control technique were examined at cruise condition and off-design simulated flight conditions (angle of attack and asymmetric distortion). All of the experimental tests were run at an inlet throat Mach number of 0.55 and a resulting Reynolds number of 1.76*105 based on the hydraulic diameter at the inlet throat. For each of the flight conditions tested, the flow control scheme was found to improve the flow uniformity and reduce the inlet distortion at the AIP. For simulated cruise condition, the total pressure recovery was improved by ~2% with the addition of flow control. For the off-design conditions of angle of attack and asymmetric distortion, the total pressure recovery was improved by 1.5% and 2% respectively. All flight conditions tested showed a reduction in circumferential distortion intensity with flow control. The cruise condition case showed reduced maximum circumferential distortion of 70% with the addition of flow control. A reduction in maximum circumferential distortion of 40% occurred for the angle of attack case with flow control, and 30% for the asymmetric distortion case with flow control. The inlet total pressure distortion was used to predict the changes in stability margin of a compression system due to design and off-design flight conditions and the improvement of the stability margin with the addition of flow control. A parallel compressor model (DYNTECC) was utilized to predict changes in the stability margin of a representative compression system (NASA Stage 35). Without flow control, all three cases show similar reduced stability margins on the order of 30% of the original stability margin for NASA Stage 35 at 70% corrected rotor speed. With the addition of flow control, the cruise condition tested improved the stability margin to 80% of the original value while the off-design conditions recover to 60% of the original margin. Overall, the flow control has been found to be extremely beneficial in improving the operating range of a compression system for the same inlet duct without flow control. / Ph. D.

This study examined test-taking attitudes and response distortion on a personality test. Consistent with our hypotheses, applicants were found to have significantly more positive test-taking attitudes and exhibit a greater degree of response distortion as compared to incumbents. In addition, test-taking attitudes were significantly associated with response distortion. However, test-taking attitudes failed to affect work performance or validity in the incumbent sample. Limitations and implications for future research are discussed. / Ph. D.