Column flotation cells have become the most popular machine designed for industrial applications that require the separation and concentration of wanted or unwanted minerals from the rest material associated in a pulp. To achieve this process separation an air sparging device, which is required to produce bubbles in the flotation cell is required. In column flotation operations, Sparger sparging devices are employed in column flotation operations to generate small bubbles into the cell with the aim to carry the the desired mineral to the surface for later be recovered and proceeded. However, field studies suggest that air injector sparging systems are not always optimized. Two of the reasonsReasons that contributinge to the lack of optimization areis unfavorable state are: (i) ineffective internal design of the sparging system, and (ii) poor operation techniques employed inby the industrial processing industrial plants. The present project intends to better understand sparging performance into the column cell and how to optimize sparging systems more effectively. To achieve this end, With this in mind, data of for gas-water injection rate, froth addition, and inlet-pressure have been collected and analyzed. The This data not only will facilitate an insight of to better operational practices that plant operators can employ to improve column performance, but it also will make it possible to correct flaws in the design of the sparging systems currently used in column flotation operations. / Master of Science

This thesis presents the results of a study of the effect of variations of systemic parameters on the structural response of single degree of freedom systems subjected to Incremental Dynamic Analysis. The systemic parameters are mass, stiffness, damping, yield strength and geometric stiffness. Each of these parameters was varied one at a time while the other values were kept constant. For each variation of parameters a set of single-record IDA curves was obtained. Five to six ground motions were used for this study to generate the single-record IDA curves. These ground motions were scaled prior to their application on the structure. The scaling factor was based on the spectral acceleration at the fundamental frequency of the structure at 5% of critical damping. The scale factor is affected if the system parameters are changed. An important issue for this study was whether to persist with scaling corresponding to the median value from the range of the values of the parameter or to update the scaling according to the system. Based on some tests using both methods, the median scaling approach was found to be more suitable. The IDA curves for variation of parameters were then investigated to identify any trends that may help in qualitatively predicting the response of a system relative to another system. The response was measured by the peak displacement and the maximum base shear of the system. A clear trend was identified when the damping or the yield strength was varied. However, no definite trend was observed when the material stiffness or the geometric stiffness of the system was varied. / Master of Science

Second harmonic (SH) microscopy represents a powerful tool for the investigation of crystalline systems, such as ferroelectrics and their domain walls (DWs). Under the condition of normal dispersion, i.e., the refractive index at the SH wavelength is larger as compared to the refractive index at the fundamental wavelength, n(2ω) . n(ω), bulk crystals will generate no SH signal. Should the bulk, however, contain DWs, an appreciable SH signal will still be detectable at the location of DWs stemming from the Čerenkov mechanism. In this work, we demonstrate both how SH signals are generated in bulk media and how the Čerenkov mechanism can be inhibited by using anomalous dispersion, i.e., n(ω) . n(2ω). This allows us to quantitatively estimate the relative strength of the Čerenkov compared to other SH contrast mechanisms in DWs, such as the interference contrast. The results are in agreement with previous experiments based on the geometric separation of the signals. Due to the observed, strong Čerenkov contrast, such signal contributions may not be neglected in polarimetry studies of ferroelectric DWs in the future.

The Memphis, Tennessee National Weather Service (NWS) currently has issues with their atmospheric dispersion index (LVORI), and is looking for a new index that better represents smoke dispersion in their County Warning Area (CWA). Forecast soundings at hour 00 and hour 48 from the North American Mesoscale (NAM) model were collected at various locations in the southeastern United States. Using the data collected, a new index equation was developed. A bootstrapping analysis was performed to determine if the mean index number corresponding to low visibility was statistically significantly different and greater than the mean index number corresponding to high visibility for forecast hour 00 and hour 48. Based on the results of this study, the mean index number was greater for low visibility, but was not statistically significantly different for forecast hour 00. For forecast hour 48, the mean index number was greater and statistically significantly different for low visibility.

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(This thesis consists of two parts.) Part I Comparison of Traveling Wave and Gain-Clamped Semiconductor Optical Amplifiers. Today's Wavelength Division Multiplexing (WDM) optical networks are getting dynamic light-path reconfigurable and optical transparent. Optical amplification without optoelectronic conversion is a key technology in all-optical networks. semiconductor optical amplifier (SOA) is a very potential device in this field. Besides the linear amplification, the nonlinear features of SOA make it has a broad application in wavelength conversion, tunable wavelength filter, optical switching and optical logic. The simple structure and very compact size of SOA indicate the essential low-cost and compatibility of integration. Resonant cavity is the basic structure of conventional SOAs, while gain-clamped SOAs (GC-SOAs) provide a constant gain which raises a lot of interests in applications. SOA with Distributed Bragg Reflectors (DBR) is one of the structures to realize the clamped gain. In this thesis the performances of traveling wave SOA (TW-SOA) and DBR-SOA are compared through a dynamic model. This model consists of a distributed feedback wave equation, a carrier rate equation and a material gain model, thereby can be used to simulate both of the two SOAs. To balance the time cost of simulation and the accuracy of the result, three important non-physical parameters, simulated bandwidth, cavity discritization and frequency discretizaiton, are investigated. The simulation results show that DBR-SOA has a very stable device gain which is independent on input optical power. From a noise level point of view DBR-SOA and TW-SOA have different characteristics. These comparison is conducted with both large signal input and small signal input. In addition, a desirable application, SOA in a multi-channel WDM system, is also simulated with GC-SOA and TW-SOA. The Bit Error Rate (BER) of TW-SOA increases greatly due to inter-channel cross talk, while the BER of GC-SOA is virtually constant with the variation of WDM channel number. Another application, wavelength converter, shows TW-SOA is very useful in non-linear application. Part II Impact of Dispersion on Hybrid of Frequency-Hopped Optical CDMA and WDMA Networks. A new analytical formula for analysis of the system performance of the Hybrid of Wavelength Division Multiple Access (WDMA) and Code Division Multiple Access (CDMA) is developed and presented. The effects of fiber dispersion and inter-channel crosstalk are considered and their impact on system performance is analyzed in terms of power penalty. Finally, methods to overcome the effects of the fiber dispersion are discussed. / Thesis / Master of Applied Science (MASc)