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This research explores the possibility of reproducing mixing decisions of a skilled audio engineer with minimal human interaction that can improve the overall listening experience of musical mixtures, i.e., intelligent mixing. By producing a balanced mix automatically musician and mixing engineering can focus on their creativity while the productivity of music production is increased. We focus on the two essential aspects of such a system, frequency and dynamics. This thesis presents an intelligent strategy for multitrack frequency and dynamics processing that exploit the interdependence of input audio features, incorporates best practices in audio engineering, and driven by perceptual models and subjective criteria. The intelligent frequency processing research begins with a spectral characteristic analysis of commercial recordings, where we discover a consistent leaning towards a target equalization spectrum. A novel approach for automatically equalizing audio signals towards the observed target spectrum is then described and evaluated. We proceed to dynamics processing, and introduce an intelligent multitrack dynamic range compression algorithm, in which various audio features are proposed and validated to better describe the transient nature and spectral content of the signals. An experiment to investigate the human preference on dynamic processing is described to inform our choices of parameter automations. To provide a perceptual basis for the intelligent system, we evaluate existing perceptual models, and propose several masking metrics to quantify the masking behaviour within the multitrack mixture. Ultimately, we integrate previous research on auditory masking, frequency and dynamics processing, into one intelligent system of mix optimization that replicates the iterative process of human mixing. Within the system, we explore the relationship between equalization and dynamics processing, and propose a general frequency and dynamics processing framework. Various implementations of the intelligent system are explored and evaluated objectively and subjectively through listening experiments.

One of the most challenge issues in oil and gas industry is the corrosion ofpipeline materials caused by carbon dioxide (CO2) and hydrogen sulfide (H2S). Theprecipitation of corrosion product layers, their characteristics, composition, and kinetics,play a key role in governing corrosion behaviors. The present project is focused on onekey aspect in understanding and modeling the effect of surface layers: the investigation ofthe precipitation kinetics of corrosion product on carbon steel, the most preferredconstruction material in the field. The study focuses as well on brines containing highconcentrations of dissolved NaCl, a situation also commonly encountered in the oil andgas industry. The first part of the project aims at improving the accuracy in thedetermination of species concentration in CO2 and H2S aqueous environments. Theconsumption of ferrous ions due to the presence of chloride ions was addressed. Severalexpressions related to H2O/CO2 and H2O/H2S equilibrium speciation were updated basedon literature data. A previously well accepted expression for iron carbonate (FeCO3)solubility limit was re-calibrated against experimental data to better account for saltconcentration effects. A methodology was developed for using Electrochemical QuartzCrystal Microbalance (EQCM) for the study of precipitation kinetics of both ironcarbonate and iron sulfide (FeS), as EQCM is a technique providing very accurate in-situmeasurement of surface mass change. Repeatable and consistent precipitation rates ofFeCO3 obtained via the EQCM across different substrates, temperatures, and sodiumchloride (NaCl) concentrations suggest that increasing NaCl from 1 wt.% to 9 wt.% didnot change the precipitation rate significantly. Based on the measurements, a kineticsmodel was proposed to describe the FeCO3 precipitation rate in CO2 environments withvaried NaCl concentrations. For FeS, the inherent complexity of the system limited thescope of the study and the applicability of the EQCM measurements. However, a linearrelationship between its precipitation rate and saturation level was observed in 1 wt.%NaCl solutions. Kinetics models for FeS precipitation were proposed consideringdifferent possible FeS precipitation pathways. It was also noticed that FeS was affectedmore by surface water chemistry than bulk water chemistry when the saturation level waslow in the bulk solution. This requires a better understanding of surface speciation.Consequently, in the last part of this work, a mechanistic model was modified to predictuniform corrosion behavior of carbon steel in CO2 and H2S environments based on waterchemistry on steel surface. By enabling the prediction in polarization conditions, thismodified model showed that the surface speciation can be significantly different frombulk speciation with or without polarization.

D-region is the lowest part of the ionosphere, ranging from about 60 km to 90 km. This thesis uses incoherent scatter radar (ISR) data obtained from the Arecibo Observatory, Puerto Rico, to study the D-region structure and associated phenomena. We have described a methodology of the data processing. The thesis focuses on the relationship between ISR spectral width and ionospheric parameters in the D-region, such as ion temperature, ion-neutral collision frequency and ion mass. The effects that negative ions and Doppler broadening have on the ISR spectrum are discussed. A detailed discussion on the ion-mass and ISR spectral width is included in this study.

Circadian rhythms are cycles of physiology and behavior that repeat at daily intervals (~24 hours) and are present in all kingdoms of life. The expression of many genes involved in carbohydrate and lipid metabolism is under circadian control. Circadian rhythms are driven by circadian oscillators at the molecular level via transcriptional and post-translational feedback loops generated by a set of interplaying clock proteins. The ratio of reduced to oxidized nicotinamide cofactors has been shown to regulate the DNA binding activity of CLOCK(NPAS2):BMAL1 transcription factor complexes. The structural basis for this interaction is unknown. Crystals were obtained of the bHLH domains of CLOCK and BMAL1 bound to E-box DNA, but the initial crystals failed to produce high-resolution diffraction patterns. The effects and affinities of the nicotinamide cofactors on protein dimer formation or E-box DNA binding were determined, but failed to see any direct evidence for NADPH binding to CLOCK or BMAL1. Nocturnin is a mammalian protein that exhibits a sharp peak of expression at early night, and is thought to regulate circadian gene expression post-transcriptionally by acting as a deadenylase, degrading of poly(A) tails from circadian mRNAs transcribed from clock controlled genes. Genetic studies have shown nocturnin rhythmically regulates target transcripts directly or indirectly in tissues such as adipose, liver, and muscle. Therefore, nocturnin is a potential key mediator between the circadian clock and energy metabolism and a potential target for understanding and treating metabolic disease. The function and mechanism of nocturnin remain unclear. Constructs for producing catalytically active nocturnin have been designed and cloned. Assays for monitoring nocturnin deadenylase activity have been designed and optimized. Substrate scope and preliminary kinetic characterization of nocturnin have been carried out. Recently, three natural products containing a novel core scaffold indolotryptoline with antitumor activity have been isolated from soil actinomycetes. One of them is borregomycin A, of which gene cluster includes two genes encoding proteins with homology to previously described two-component tryptophan halogenases. However, no crystal structures have been reported for the flavin reductase components of two-component halogenases. BorF has been predicted to be its flavin reductase component. The crystal structure of flavin reductase BorF with bound FAD was determined to 2.37 Å in this study.

The objective of this work is to gain information that could be used to design full scale mixing systems, and also could develop a design guide that can provide a reliable prediction of the power draw of different types of impellers. To achieve this goal, the power number behavior, including three operation regimes, the limits of the operation regimes, and the effect of baffling on power number, was compared across the full Reynolds number spectrum for Newtonian fluids in a laboratory-scale agitator. Six industrially significant impellers were tested, including three radial flow impellers: D-6, CD-6, and S-4, and also three axial flow impellers: P-4, SC-3, and HE-3.Results in laminar regime indicate that baffling has no effect on power number in this operation regime. There is an inversely proportional relationship between power number and Reynolds number. The upper limit for this operation regime should be lower than 10, the limit commonly noted in the literature. The product of power number and Reynolds number in this particular regime is approximately proportional to the number of blades for these six impellers; however, other shape factors that were not included in this study also contribute to it.In turbulent operation, baffling has a significant effect on power number: the power number for most impellers remains relatively constant in the baffled configuration while that for unbaffled configuration decreases with increasing Reynolds number. The impeller blade number is not the dominant factor that affects power number in this regime. Two hydrofoil impellers, SC-3 and HE-3, exhibit much lower power numbers when compared with the other impellers. Additionally, the impellers with higher power numbers in baffled tank tend to have lower ratios between unbaffled power number and average baffled power number when comparing at same Reynolds number.No difference between two configurations, baffled and unbaffled, exists at low Reynolds number end of transitional regime, and the difference starts at intermediate Reynolds number and increases with an increase of Reynolds number. In the baffled configuration, four out of six impellers exhibit a minimum power number. In the unbaffled configuration, power numbers drop with increasing Reynolds number throughout the entire transitional regime for all impellers. The ratio of unbaffled to turbulent average power number for the six impellers retains a consistent order through the entire Reynolds number range with two high efficiency impellers having the highest ratio, then pitched blade impeller, and three radial flow impellers having the lowest ratios.