Shippagan Gully is a highly dynamic tidal inlet located on the Gulf of St-Lawrence near Le Goulet, New Brunswick. This tidal inlet is highly unusual due to the fact that the inlet has two open boundaries with phase lagged tidal cycles that drives flow through the inlet. Over the past few decades, the shipping activities through the inlet have been threatened due to the narrowing of the navigation channel caused by deposited sediment on the east side of the channel. Many engineering projects have been undertaken at Shippagan Gully in order to try and mitigate the deposition problem. However, these attempts have either been unsuccessful or the engineered structures have deteriorated over the years. This study uses the CMS-Flow and CMS-Wave numerical models to provide guidance concerning the response of the inlet to various potential interventions aimed at improving navigation safety.

The evolution of the sulphur content of humic substances extracted from a near-shore sediment core was investigated. Special attention was taken to avoid S contamination of the humic materials during sample handling and extraction. The S/C ratios increased continuously with depth to values which strongly suggest S addition to the humic matrix during early diagenesis by reactions between organic matter and H₂S or its oxidation products. The light isotopic composition of this organic sulphur supports this view; however, subsequent isotopic exchange has obscured the mechanism initially involved. Since a large fraction of the enrichment occurred above the sulphidic zone, redox boundaries, such as the interface of anoxic microniches within the more oxidized zones, or the sulphidic/suboxic boundary of the sediment column, must have been important sites for S addition. The influence of sulphur enrichment on the complexing capacity of humic materials was also investigated, and it was shown that S-addition increases significantly the number of sites on which Cu is irreversibly bound. Iodine is characteristically enriched at the surface of hemipelagic and nearshore sediments deposited under oxygenated conditions. In such sediments, bulk I/Corg ratios usually decrease with depth to values which are characteristic of anoxic sediments, reflecting a preferential release of iodine during early diagenesis. There is some debate as to whether sedimentary iodine is associated with the iron oxyhydroxide phase or with the organic fraction, and whether the decrease in I/Corg with depth is due to the dissolution of the iron oxyhydroxides or the decomposition of labile organic matter. In this study, it is shown that in a surficial hemipelagic sediment sample and in a nearshore sediment core iodine is mainly associated with the organic fraction and, moreover, that humic substances are involved in the surficial iodine enrichment. Laboratory experiments on the uptake and release of iodine by and from sedimentary humic substances also suggest a mechanism whereby humic materials reduce iodate at the sediment/water interface to an electrophilic iodine species which further reacts with the organic matter to produce iodinated organic molecules. During burial, this excess iodine could be displaced from the organic matrix by nucleophiles such as sulphide ions or thiosulphate, thus providing a possible explanation for the decrease in I/corg ratio with depth observed in many nearshore and hemipelagic sediments. Bulk metal concentrations were measured in the sediments of Saanich Inlet in an attempt to establish the occurrence of trace metal enrichments in the anoxic central basin. Ba, Ni, V, Cr, Zn, Pb, Cu, and Mo were found to be enriched in the anoxic ooze over the possible contributions from lithogenous sources. Spatial and seasonal variations in the chemical composition of the settling particulates collected with interceptor traps gave further indications of the mode of incorporation of these metals. Biogenic Ba and Cr appeared to be associated with opaline silica, although alternative explanations are also possible, particularly for Ba. Zinc seemed to be added to the sediment essentially in association with planktonic materials, while Cu required an additional source directly linked to the anoxic environment. Similarly, Ni, V, and Mo were added to the anoxic sediments by reactions occurring at the sediment-water interface. In the nearshore environment studied here, these metals were not associated to any significant extent with planktonic materials, particularly Ni and Mo. Of all the elements analyzed, Mo showed the largest enrichment in the anoxic sediments of Saanich Inlet. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Turbidity currents, both continuous flow and surge-type, have been detected with acoustic sounders operating at 42.5, 107 and 200, kHz. The turbidity currents are associated with the discharge of mine tailing into Rupert Inlet. A linear relation is obtained between the backscattered acoustic signal at 200 kHz and the one-half power of suspended particulate concentration from 10 to 1000 mg 1⁻¹. This relation is consistent with Rayleigh scattering theory in form and (relative to a standard target) amplitude, and is used to generate a cross-sectional profile of sediment concentration in the discharge plume. Estimates of surge speeds from the acoustic records based on a universal shape for density current heads range from 30 to 120 cm s⁻¹. The excess density of one surge was estimated from the reverberation amplitude to be 0.12 g cm⁻³. The additional attenuation of sound waves by suspended particles is important in turbidity currents and may be used to estimate suspended particulate concentration. Thermal processes contribute very little to the additional attenuation by particles with the grain densities of common minerals. A leveed submarine channel extended from the point of the tailing discharge (outfall) over the surface of the tailing deposit as early as 1974. The upper reach of this system was buried in 1978, and by late 1979 a new channel had developed. In 1976-77, the original channel consisted of: (1) a left-hooking upper reach with an average slope of 2.2°, (2) a middle reach (1° slope) with pronounced meanders (700-1100 m wavelengths) "increasing in curvature with distance downstream and (3) a straight lower reach (0.5° slope). The cross-sectional area of the channel decreased with distance downstream, excepting an increase in the first 100-200 m, until the channel disappeared about 5.5 km from the outfall. Acoustic records of the discharge plume in bends indicate overspill from the outer bank and an upward tilt of the upper interface away from the centre of bend curvature. The interfacial slope is steeper than indicated by the cross-channel difference in levee heights. These records together with observed tidal currents suggest that the left hook in the upper reach is caused by a mechanism similar to that which has been suggested for deep-sea channels. Turbidites in gravity cores from the levees are present as layers of vertically-graded, Cu-rich and Fe-poor sand and silt, some of which have load-casted flame-structures or load-pockets at their basai contacts. These layers comprise more of the sediment column with distance down-channel, suggesting that levee-building by overbank spillage from continuous flow becomes less important, and that most of the material transported through the lower reach is carried by turbidity surges. Surge recurrence intervals of 2-5 d are obtained from the number turbidites per core and the local deposition rate. The latter ranged from 0.3-4 m yr⁻¹, as given by changes in water depth, in tailing thickness from seismic reflection surveys, and in diatom frustule abundance in the cores. A model of continuous turbidity flow in submarine channels including entrainment is applied to the Rupert Inlet channel. Results are consistent with a sediment budget based on changes in the tailing deposit volume, and with turbidity surge recurrence intervals. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Aspects of the biology of the sepiolid squid Rossia pacifica Berry were studied from specimens obtained by otter trawling at Cape Lazo Gully and Saanich Inlet, British Columbia. Temperature, salinity, and sediment size at Cape Lazo Gully varied from 7.18°C to 11.00°C, 28.01 °/oo to 30.21 °/oo, and from less than l00μd to over 250μd respectively. Living specimens in the laboratory exhibited color changes from dark red-brown to opalescent grey-green. They did not mimic the color of the substrate. Comparisons of the morphometric indices of R. pacifica with other species of this genus showed differences in some indices but not in others. The arm formula is inconsistent, the most common being 3>2>4>1 and 3>2=4>1. The lower beak differs from that of R. maarosoma by having a "tooth" on its shoulder. In an aquarium Rossia spent most of its time resting on the bottom either in a horizontal position or with the anterior end elevated. The squid usually formed a depression in the sandy bottom to rest in. In some instances they threw sand onto their backs. Fish were caught with the tentacles and held with the arms while being eaten. Stomach analysis revealed that crustacea were present in 86.6% of the stomachs that contained food, while fish were present in 16.6%. Shrimp formed the largest portion of the crustacea in the diet. Bivalve molluscs, squid, and ostracods were occasionally found. Proportions of crustacea to fish in the diet were higher in smaller squid and decreased in larger animals. Seasonal variations in the diet were correlated with the biomass of shrimp in the area where the squid were collected; when a low biomass of shrimp was present the squid had a higher proportion of fish in their diet. The female R. pacifica are slightly larger than the males of the same age and grow to a larger size than do the males. The male and female reproductive systems are described. Gonad indices show that the ovaries and nidamental glands begin to mature when the females have a dorsal mantle length of approximately 24.0 mm. Spermatophores were not found in males smaller than 22 mm mantle length. The proportion of males containing spermatophores was 9% at 22 mm and increased through 17% at 24 mm, 50% at 26 mm to 90% at 28 mm. During mating the male attaches to the female from below by means of his second, third, and fourth pairs of arms. Spermatophores are transferred into the dorsal region of the female's pallial cavity by his dorsal, hectocotylized arms. The sex ratio of males to females found at Cape Lazo Gully was 1.2:1.0. Spawning occurs in the fall with the most active period occurring from August through October. This may be correlated with an increase in the water temperature, during this time. The squid have a life span of one year, at the end of which they mate, spawn, and die. / Graduate

This diploma thesis contains several individual parts. It's especially about summary in the area of one-way inlets: the energy efficiency of the inlets and influence of the neighbouring inlets on them, the phases of creation of surface vortices, the influence on the vortex structures by the mutual operation of the neighbouring inlets and also the methods used to determine the critical and safe depth of dive of inlet against the creation of surface vortices. It also includes the description of process and the evaluation of laboratory tests, which are focused on the assessment of the effect of the mutual operation of inlets on their energy efficiency and the creation of higher intensity surface vortices. Important part of this diploma thesis is also a comparison of the achieved results with the results of the authors who have dealt with this issue.

Within a gas turbine engine, the turbine nozzle guide vanes are subjected to very harsh conditions from the highly turbulent and hot gases exiting the combustor. The temperature and pressure fields exiting combustors are highly nonuniform and dictate the heat transfer and aero losses that occur in the turbine passages. To better understand these effects, the goal of this work was to develop an adjustable combustor exit profile simulator for the Turbine Research Facility (TRF) at the Air Force Research Laboratory. The TRF is a high temperature, high pressure, short duration blow-down test facility that is capable of matching several aerodynamic and thermal nondimensional engine parameters including Reynolds number, Mach number, pressure ratio, corrected mass flow, gas to metal temperature ratio, and corrected speed. The primary research objective was to design, install, and verify a non-reacting simulator device that can provide representative combustor exit total pressure and temperature profiles to the inlet of the TRF turbine test section. This required the upstream section of the facility to be redesigned into multiple concentric annuli that serve the purpose of injecting high momentum dilution jets and low momentum film cooling jets into a central annular chamber, similar to a turbine engine combustor. The design of the section allows for variations in injection levels to generate different pressure profiles with elevated turbulence. The dilution and film cooling temperatures can also be varied to create a variety of exit temperature profiles similar to real combustors. The impact of the generated temperature and pressure profiles on turbine heat transfer and secondary flow development was ultimately investigated. Proposed optimal inlet conditions for the turbine tested in this research effort were determined based on the measured data corresponding to the combustor simulator exit profiles that minimized vane heat transfer and total pressure loss. / Ph. D.

An increased understanding of how inlet flow distortion affects transonic fans enables improved fan design and performance prediction. Inlet distortion refers to non-uniformities in the incoming flow properties. Complex inlet ducts in high performance aircraft result in distorted flow at the fan inlet. In this thesis, two studies were performed using Unsteady Reynolds-Averaged Navier Stokes (URANS) simulations. The first study focused on understanding how the transition abruptness between the clean and distorted sector in the inlet Pt profile as well as the circumferential extent of the distorted sector affect distortion transfer and generation through a transonic fan. Simulations on two main distortion sector sizes were carried out. For each sector size, variants with decreasing levels of transition abruptness were applied to the inlet of fan. Simulations were conducted at various operating points, ranging from choke to near-stall. Fourier-based distortion descriptors were used to quantify levels of distortion transfer and generation at various axial locations. It is shown that variations in rotor incidence occur as a result of the applied Pt distortion at the inlet. A less abrupt transition diminishes the local extrema in rotor incidence, which in turn reduces the amount of distortion transfer and generation through the rotor. The near-stall condition is affected most of all operating points considered, with a 23.4% average reduction in the amount of distortion transfer at any span. The size the inlet distorted sector affects the amount of distortion transfer and generation, particularly at the near-stall operating point. This is shown to be due to the dynamic response of the fan. The second study compared the mechanisms of stall inception for cases of both clean and distorted inlet flow. In each instance, the mechanism of stall inception is shown to be interactions between the detached bow shock and the tip clearance vortex. These interactions result in the formation of two vortices within the blade passage. The location and strength of these vortices affect the LE spillage in the adjacent blade rows. Stall inception occurs when the bow shock has moved far enough upstream to allow the resultant vortices from shock/tip clearance vortex interaction to pass in front of the leading edge. When inlet distortion is present, mass redistribution upstream of the fan results in variations in rotor incidence. Within the high incidence region, the bow shock is detached 3.9%-8.1% chord more than the clean inlet case, making LE spillage more severe. The rotating stall cell grows out of the stalled passages present at the near-stall operating point and ultimately extends 180° circumferentially and 18.7% span radially. Understanding the effects of distortion on the mechanisms of stall inception will allow appropriate steps to be taken to extend the stable operating range of modern commercial and high performance fans.

Membrane inlet mass spectrometry was used to observe nitric oxide in the well-studied reaction of nitrite with hemoglobin. The membrane inlet was submerged in the reaction solutions and measured NO in solution via its flux across a semipermeable membrane leading to the mass spectrometer detecting the mass-to-charge ratio m/z 30. This method measures NO directly in solution and is an alternate approach compared with methods that purge solutions to measure NO. Addition to deoxy-Hb(FeII) (near 38 μM heme concentration) of nitrite in a range of 80 μM to16 mM showed no accumulation of either NO or N2O3 on a physiologically relevant time scale with a sensitivity near 1 nM. The addition of nitrite to oxy-Hb(FeII) and met-Hb(FeIII) did not accumulate free NO to appreciable extents. These observations show that for several minutes after mixing nitrite with hemoglogin, free NO does not accumulate to levels exceeding the equilibrium level of NO. The presence of cyanide ions did not alter the appearance of the data; however, the presence of 2 mM mercuric ions at the beginning of the experiment with deoxy-Hb(FeII) shortened the initial phase of NO accumulation and increased the maximal level of free, unbound NO by about twofold. These experiments appear consistent with no role of met-Hb(FeIII) in the generation of NO and an increase in nitrite reductase activity caused by the presumed binding of mercuric to cysteine residues. These results raise questions about the ability of reduction of nitrite mediated by deoxy-Hb(FeII) to play a role in vasodilation.

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Thesis advisor: Gail Kineke / Thesis advisor: Noah Snyder / Salt marshes are some of the world’s richest ecosystems and provide a plethora of benefits to coastlines and bays in terms of storm protection and chemistry. To ensure salt marsh survival under increasing rates of sea level rise, management practices have been trending towards natural sustainability measures to increase marsh resilience. To benefit these efforts, it is necessary to understand how natural salt marshes respond to environmental change in terms of sediment deposition and evolution of vegetation and open water. This study uses aerial image digitization to understand how Nauset Marsh in Cape Cod MA, a protected salt marsh on Cape Cod National Seashore, has responded to sea level rise and half a century of inlet migration. Digitized images from 1974-2019 were used to track changes to vegetation extent and open water features during study periods of different inlet migration stages. Observed changes were used to ascertain trends of marsh loss or adaptation based on previous research on ponding cycles and vegetation extent. Results indicate that Nauset Marsh has been relatively stable over the last half century, with the most significant change observed in Vegetated Marsh loss of 6.71% ± 3.19 primarily due to edge erosion near the present-day inlet. Despite net feature stability, significant differences in feature evolution trends were observed during different stages of inlet migration. Most notably, inlet breaching and migration correlated with dynamic feature changes throughout the marsh, while the static inlet period correlated with expansion of open water features near the inlet location. The evolution of Nauset Marsh suggests that inlet migration improves marsh resilience through periodic increases in sediment deposition in a natural salt marsh with sufficient sediment supply. / Thesis (MS) — Boston College, 2023. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.