identifier: Gauthier, Jeremy <https://research.library.mun.ca/view/creator_az/Gauthier=3AJeremy=3A=3A.html>   (2018) Development of a high-throughput method of analysis for selected neonicotinoids.  Masters thesis, Memorial University of Newfoundland.

abstract:
Neonicotinoids are a class of insecticides recently developed as more environmentally
friendly alternatives to traditional organophosphate, carbamate, and pyrethroid insecticides.
Through continuously expanding global use of neonicotinoids, they have
become the most widely use insecticides. In addition, there are increasing concerns
regarding their use, particularly regarding their effects on pollinating and aquatic
species. Regulatory agencies are beginning the phase-out and restriction of neonicotinoid
insecticides in Europe and North America.
This research details the development of a comprehensive method of analysis for
neonicotinoid insecticides in aqueous environmental matrices. Analytical methods are
developed for routine, high-throughput, quantitative measurements of neonicotinoids;
and new sampling, extraction, and pre-concentration techniques are examined.
By combining UHPLC with a simpler method and superficially porous column
technology, the elution program for the six neonicotinoids of interest is reduced from
a literature average of 9 minutes, to just 2.7 minutes for baseline separation. Additionally,
tandem mass spectrometry is used to lower instrumental limits of detection.
Separation and extraction procedures can be eliminated entirely through the adaptation
of TDU-DART-MS, methods for which were developed and optimized for the
neonicotinoids. Finally, the novel MIP-SPE procedure is used with high sensitivity
to selectively extract neonicotinoids of interest from environmental matrices. Method detection limits are lowered to fall between 0.1 and 1 ng L⁻¹, and local waterways are
shown to demonstrate a presence of neonicotinoids while using this method.


identifier: Elhajare, Mustafa Ahmed <https://research.library.mun.ca/view/creator_az/Elhajare=3AMustafa_Ahmed=3A=3A.html>   (2018) Experimental investigation of ice accumulation on horizontal axis wind turbines.  Masters thesis, Memorial University of Newfoundland.

type: Thesis NonPeerReviewed

abstract:
Wind energy is the world’s fastest growing source of electricity production. If this trend continues, sites that are plentiful in wind energy will be efficiently utilized. Many sites are located in cold, wet regions such as northern coastal regions of Canada. This thesis studies ice accumulation on wind turbine blade, at several positions, for three different wind speeds at -10 ᵒC and LWC of 0.6 g/m³.
NACA 63415 airfoil was studied in this thesis. The blade model was designed to be suitable to the specifications of wind turbines. The blade was positioned at 0ᵒ, 45ᵒ and 90ᵒ, and the wind speeds were 3.5 m/s, 4 m/s and 5 m/s. In addition, some tests were conducted with changes in the angle of attack, from 0ᵒ to 90ᵒ with the angular position of the blade and wind speed maintained constant. All tests were conducted in a climatic wind chamber with a fan and two spray nozzles. Two different measurements (chord and thickness) are taken at four location of the blade span. All tests adjusted at three hours.
Therefore, these parameters produced the highest accumulation of ice on the chord and the thickness of the blade and recorded the highest weight of ice. In this study, the highest accumulation of ice on the chord and the thickness of the blade was at (V = 5 m/s, θ = 45ᵒ and α = 45ᵒ) where it was approximately 61 mm and 47 mm respectively, and the maximum weight of ice on the blade was 6.7 kg. When the angle of attack changed, the weight of the ice increased slightly, where the highest ice weight at the angle of attack of 90ᵒ was 7.2 kg.


identifier: Jack, Meghann E. (Meghann Elizabeth) <https://research.library.mun.ca/view/creator_az/Jack=3AMeghann_E=2E_=28Meghann_Elizabeth=29=3A=3A.html>   (2018) Nineteenth-century barns in St. Mary's, Nova Scotia.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
This thesis examines adaptation and change in nineteenth-century timber frame barn
building in St. Mary’s, a fertile river valley that extends through Pictou and Guysborough
counties of Northeastern Nova Scotia. The study assesses how barn design evolved on the
St. Mary’s landscape through the identification of a basic chronology of local building
types: Phase I, The Early English Barn (1800 to mid-century) and Phase II, The Reform-
Era Barn (mid-century to early 1900s). The study contextualizes St. Mary’s barns in their
local geographic and economic settings, and within wider nineteenth-century culture.
Barns ultimately reveal changing notions concerning agriculture and the farm in St.
Mary’s. They address the interdependence of farm productivity and built form, and
express the shift towards more intensified, market-oriented, and capitalistic farming
strategies in the mid-to-late decades of the nineteenth century. Barns became larger
through a process of extension as the century progressed, and incorporated new features
such as manure cellars that enhanced agricultural productivity. The barns also speak to
the ways ideological discourses, like reform and improvement, influenced architectural
choice and how competing cultural attitudes toward traditional continuity and progressive
change ultimately moderated the acceptance of new ideas towards farm buildings.


identifier: Bishop, Nicole <https://research.library.mun.ca/view/creator_az/Bishop=3ANicole=3A=3A.html>   (2018) The effects of motion environments on search and rescue task performance and postural control.  Masters thesis, Memorial University of Newfoundland.

abstract:
The purpose of this master’s thesis was to investigate the risks associated with performing
a vigilance task in a simulated moving environment. More specifically, the effects of
simulated motion on both postural stability and the performance of a simulated search and
rescue (SAR) task. Many offshore occupations are considered strenuous and potentially
dangerous in nature due to continuous wave-induced perturbations. These perturbations
are responsible for accidents and injuries related to reduced postural stability and
increased work-related energy demands. To investigate these potential adverse effects, a
single data collection utilized a motion platform and a 360-degree screen which displayed
visuals synchronized to platform motions. The results show that performing a SAR task in
a simulated moving environment has a significant adverse effect on SAR task
performance and postural response. As simulated wave motions increased, there was a
decrease in SAR task performance and increased lower limb muscle activations, as well
as the number of steps taken. These results indicate the likelihood of increased risk of
falls and human factors errors when performing a simulated SAR task in a motion
environment.


identifier: Roy, Shubhagata <https://research.library.mun.ca/view/creator_az/Roy=3AShubhagata=3A=3A.html>   (2018) Numerical modeling of progressive and retrogressive failure of submarine slopes with a sensitive clay layer.  Masters thesis, Memorial University of Newfoundland.

abstract:
Submarine landslides are major concerns in offshore oil and gas development activities, as they can displace an enormous amount of sediment compared to onshore landslides. Among the different triggering factors identified in the past, the presence of a weak strain-softening clay layer and earthquake loading have been considered the primary causes of many large-scale landslides. Depending upon geometry, loading conditions and sediment properties, different types of failure patterns (e.g., slab, spread, ploughing, run-out) have been observed in the field. In the present study, a Eulerian-based finite-element (FE) approach in Abaqus software is used to study large-scale submarine landslides for varying slope angles.
The main objective of the present study is to numerically simulate the failure of submarine slopes with strain-softening clay layers triggered by two factors: i) shear strength reduction in a thin zone of soil which could be occurred due to gas hydrate dissociation, and ii) earthquake loading. Two approaches are used to model earthquake loading: (i) complete dynamic modeling base on acceleration–time history and (ii) modified pseudostatic loading with a simplified pulse of horizontal acceleration. A model for strain-softening behaviour of clay is implemented in the FE simulation, and analyses are performed for varying slope angles over a large seabed section. The FE simulations show that an initial shear band of sufficient length parallel to the seabed in the steeper part of the slope could cause a large-scale landslide by progressive formation of failure planes, both in upslope and downslope areas. In upslope areas, the failure pattern is similar to spreads commonly observed in sensitive clay slopes in onshore environments. In downslope areas, the failures tend to be similar to ploughing. The obtained failure patterns, ploughing distances, and retrogression distances for both types of earthquake loading are compared. Simple pulse-type pseudostatic loading can be used to reasonably model earthquake-induced landslides.


identifier: Kavanagh, Mark B.(Mark Bradley) <https://research.library.mun.ca/view/creator_az/Kavanagh=3AMark_B=2E=28Mark_Bradley=29=3A=3A.html>   (2018) Time-dependent aspects of fracture in ice.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
An important aspect of ice fracture that is yet to be fully resolved in determining the
loads and pressures during an interaction with ice is the presence and growth of fractures.
Practical applications include icebreakers ramming into ice pack or structures
operating in ice-prone regions.
Existing models often use a simplified view of ice mechanics, often based on only
the elastic properties, which tend to overestimate the strength of the ice. It has long
been known that ice exhibits time-dependent properties, including its strength. This
is known from ship ramming experience as well as field and laboratory experiments.
Accounting for these time-dependent aspects of ice behaviour would allow for a more
analytical approach to interaction modelling and complement the empirical data that
is used currently in design practice.
The aim of this thesis is to provide a better understanding of ice fracture that
occurs during an interaction. To better understand the viscoelastic properties of ice,
an extensive review of the literature was performed. In particular, an in-depth review
of linear elastic fracture mechanics was performed, as it it critical to the foundations
of the viscoelastic fracture theory.
To guide the development of a new viscoelastic fracture model, three sets of experiments
were performed. The first was an indentation series, scaled down from similar
field experiments, that displayed several fracture properties of ice. These properties
were rate-dependent fracture, delayed fracture, and scale effects.
The next two series, designed to study a single crack, used ice samples under 4-
point bending. The first of these were constant loading rate test to further study the
rate-dependent fracture properties of ice, resulting in ice that is weaker under faster
loading in a decreasing power law relationship. The second of these applied constant
loads just below the breaking point to show that ice undergoes delayed fracture. The
data suggests a decreasing power law between applied load and time to failure for
these samples.
Building on previous works in viscoelastic fracture theory, and making use of the
insights gained from the experiments, a new model has been developed to predict the
fracture properties of ice. The model accounts for the delayed fracture of ice and
provides insights into the time-dependent fracture properties of ice, as was seen in
the laboratory and field experiments. The model, based on viscoelastic theory, was
shown to reasonably model time to failure for ice beams under constant load, as well
as the fracture strength of ice beams under different loading rates. The model, besides
expanding the old theories to beam bending geometries, was also shown to work for
compact tension specimens with a few minor changes.


identifier: Gao, Xiangpeng <https://research.library.mun.ca/view/creator_az/Gao=3AXiangpeng=3A=3A.html>   (2018) Development of novel polysaccharide based adsorbents for precious metal recovery.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
Biosorption is a green, efficient, and low cost method to recover precious metals from aqueous solutions compared to conventional methods. Over the past two decades, great efforts have been made to fabricate biosorbents to recover precious metals from natural polysaccharides in batch adsorption process. However, most of the studies were focused on mono-metallic solutions, while biosorption from multi-metallic solutions should be addressed as it is more closely parallels the real life scenario. In addition, the adsorption mechanism is not clearly defined, especially for the competitive adsorption of multi metal ions. Moreover, most of the polysaccharide based adsorbents synthesized are not suitable to be packed into fixed-bed columns for large-scale processes due to their poor mechanical strength, improper particle sizes, and extremely slow mass transfer rates. To fill these research gaps, this study mainly focuses on fabrication of polysaccharide based adsorbents with good selectivity as well as physical structure and mechanical strength, understanding the selective adsorption mechanism, and dynamic adsorption in fixed-bed column.
In this work, five polysaccharide-based adsorbents have been synthesized for selective adsorption of precious metals from multi-metallic solutions. Three adsorbents have been synthesized by cross-linking (or gelatinization) the polysaccharides (cellulose or sodium alginate), and then grafting functional groups onto the surface of the adsorbents. These adsorbents have exhibited outstanding selectivity towards precious metals as well as high capacities. Biosorption of Au (III) in acidic media are mediated by the electrostatic and covalent interactions between Au (III) and hydroxyl, carboxyl, amino, and –C=S functional groups. Porous epichlorohydrin/thiourea modified alginate adsorbent (PETA) has been synthesized by direct templating method. PETA has shown great capacities and selectivity as well as remarkable improvement in adsorption kinetics than the nonporous adsorbent. In order to achieve a smaller diameter for the purpose of fixed-bed adsorption test, a microsphere adsorbent (ETA) has been synthesized by facile emulsion method of a water-in-oil emulsion of modified alginate. ETA microspheres were packed into a fixed-bed column and a mathematical model was applied to describe the breakthrough curves of Pd (ІІ) and Cu (ІІ) ions under different experimental conditions.
Several characterization methods were applied to investigate the adsorption mechanism. The polysaccharides, synthesized adsorbents, and the adsorbents after adsorption were characterized by FT-IR spectroscopy to identify the chemical bonds and functional groups. Scanning electron microscope (SEM) images were recorded to observe the surfaces and structures of the adsorbents. X-ray photoelectron spectroscopy (XPS) was used to determine the electron donors and acceptors from the shift of their binding energies. X-ray diffraction (XRD) was used to detect the reduced gold particles.
A transport-dispersive model with a linear driving force kinetics equation was utilized to predict breakthrough curves of Pd (ІІ) and Cu (ІІ) in the fixed-bed packed with ETA microspheres. A pH-dependent competitive Langmuir isotherm was developed and used in the simulation. Effects of flow rates, feed concentrations, and pH values were studied and experimental data were used to validate the mathematical model. The good agreement between the simulated and experimental breakthrough curves confirms that transport–dispersive model is capable of predicting the dynamic adsorption performance over wide operating range.


identifier: Fitzpatrick, Cheryll <https://research.library.mun.ca/view/creator_az/Fitzpatrick=3ACheryll=3A=3A.html>   (2018) When a half and a half are not a whole: putting word problems in context.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
Math word problems can be quite challenging to students. They learn early in their
formal education that there is a proper “procedural recipe” to follow when solving words
problems. Typically, it consists of taking the numbers and keyword(s) that indicate what
mathematical operation should be used coupled with whatever lesson they happen to be
learning at that moment. These word problems are usually very straightforward, applying
one mathematical operation to all the numbers present in the problem, to a situation that
largely ignores any inkling of reality, and does not include any extraneous information.
This style of mathematical problem solving however is not conducive to applying
mathematics in the real world. In the real-world situations are messy, there are often
many unknowns, and there may not always be one correct answer. How does children’s
formal education prepare them for applying their mathematical knowledge to real-world
situations? The research examining this topic has consistently shown that students have
trouble incorporating their real-world knowledge into their solution process for
mathematical word problems that require realistic considerations.
This dissertation investigates the relation between realistic problem solving and
general academic skills while also testing procedures meant to improve realistic problem
solving in Grade 6 students. After reviewing the literature on this topic in Chapter 1,
Chapter 2 focuses on how general academic abilities play a part in children’s abilities to
use their real-world knowledge. Chapter 3 examines interventions aimed at increasing
students realistic responding to realistic word problems. The results of Chapter 2 indicate
that general academic abilities are not predictors of success on realistic word problems;
however, student’s ability to provide realistic responses to realistic word problems was an independent predictor of their performance on standard word problems (e.g., those seen
in mathematics classrooms). This suggests that students’ general problems solving skills
are benefitted by their ability to incorporate realistic reasoning and for this reason
realistic reasoning is a skill worth nurturing. The result of Chapter 3 revealed that having
students respond to realistic word problems with a response sentence was only helpful for
boys and only on a particular type of word problem (Division-with-Remainder; see
Experiment 1), using examples hinders students’ ability to use their realistic knowledge
(Experiment 2), and creating a richer backstory in the word problem also does not
increase student’s use of realistic knowledge. The experiments conducted in Chapter 3
indicate that students are extremely resistant to including realistic knowledge in their
solution process. Chapter 4 provides more general discussion of the findings, and
included some additional findings not discussed in Chapters 2 and 3. Future directions in
this line of research, the implications of the dissertations findings, and some practical
applications were also discussed, but the findings reported here point to the difficulty in
teaching children to apply real-world information in problem solving situations and the
importance of doing so.


identifier: Ortega, Daniel J. Sivira <https://research.library.mun.ca/view/creator_az/Ortega=3ADaniel_J=2E_Sivira=3A=3A.html>   (2018) Alteration of the wetting character of a composite rock, through the use of nanoparticles as an enhanced oil recovery method, Ben Nevis Formation, Hebron Field, Jeanne d'Arc Basin, offshore Newfoundland, Canada.  Masters thesis, Memorial University of Newfoundland.

abstract: The Hebron Field is the fourth major offshore development in eastern Canada. Innovative and efficient techniques, such as nano enhanced oil recovery (Nano-EOR) must be applied to the Hebron Field to improve the low oil recovery projections. This research examined the feasibility of adding SiO2 nanoparticles to seawater for EOR in the Hebron Field, by analyzing the fluid-fluid interactions between nanofluids and oil and determining fluid-fluid-rock interactions between nanofluids, oil and reservoir rocks. The experiments were conducted at Hebron reservoir conditions using standard cores that best represented Ben Nevis Formation facies. Stable SiO2 nanoparticle dispersed in seawater decrease the interfacial tension (IFT), and have the function of reducing the oil-water contact angle, making the wetting character of rock surfaces more strongly water wet. The scanning electron microscope (SEM) and mineral liberation analysis (MLA) results were not conclusive. They did, however, reveal major alterations on quartz, carbonate and clay minerals. Inductively coupled plasma – optical emission spectrometry (ICP-OES) analyses verified the dissolution of carbonate minerals in the standard cores.


identifier: Murrant, Kevin <https://research.library.mun.ca/view/creator_az/Murrant=3AKevin=3A=3A.html>   (2018) Aircraft manoeuvring for sensor aiming.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

title: Aircraft manoeuvring for sensor aiming

abstract:
Airborne sensor aiming can be achieved with a fixed sensor using the manoeuvrability
of an aircraft. Such a method offers advantages in potential sensor coverage
and reduced payload complexity. Without use of a gimbal, an aircraft can be made
more robust and sensor aiming is limited only by the aircraft flight capabilities.
A novel method is developed and demonstrated for performing sensor aiming with
a fixed-wing aircraft. A creative mathematical framework is presented for both a 3D
path following controller and a method to seamlessly achieve sensor aiming while
minimizing path deviation. A simulation environment is developed based on a fit-forpurpose
aircraft model identified from live flight testing and the control algorithms
are validated.
Flight test data is presented demonstrating efficacy of the 3D path following controller.
These demonstrations also serve to validate the aircraft modelling approach
taken during controller development.
Two application examples involving airborne radar aiming for detect and avoid
and gimbal-less ground target tracking are used to illustrate the sensor aiming method.
The proposed sensor aiming methodology is both practical and feasible as supported
by results. The proposed method is applicable to both unmanned and manned aircraft.
Future work involving the concept of manoeuvrable sensors is proposed in the
conclusion.


identifier: Kim, Jenny <https://research.library.mun.ca/view/creator_az/Kim=3AJenny=3A=3A.html>   (2018) Laboratory investigations of silicon dioxide nanoparticle enhanced oil recovery for application in the offshore reservoir, Hebron Field.  Masters thesis, Memorial University of Newfoundland.

abstract: The silicon dioxide nanoparticles for enhanced oil recovery as a water additive is a growing research field. The challenge of using silicon dioxide nanoparticles offshore, such as Hebron Field, is an instability of the nanoparticles in the seawater. The use of hydrochloric acid is proposed as a silicon dioxide nanoparticle stabilizer in seawater, and its effectiveness was investigated at room temperature, and at Hebron Field temperature (62°C) over a 14-day period, via visual examination and particle size measurements. The nanofluids were then prepared by adding hydrochloric acid to the nanoparticles, then dispersing the resulting mixture in seawater for the coreflood experiments. The coreflood experiments conducted at Hebron Field conditions on the Berea sandstone cores, in which 0.01, 0.03 and 0.05 wt% silicon dioxide nanofluids were injected as a tertiary method, showed increasing oil recovery (3.3, 9.3, and 14.9% increments, respectively) with increasing nanoparticle concentration. The coreflood experiment on the Hebron Field core with 0.05 wt% nanofluid also exhibited 11.9% incremental oil recovery. The hydrochloric acid added in the nanofluid was found to have minimal effect on the recovery factor.


identifier: Shikon, Violaine <https://research.library.mun.ca/view/creator_az/Shikon=3AViolaine=3A=3A.html>   (2018) An analysis of larval fish community structure and capelin (Mallotus villosus) early life dynamics on the Northeast coast of Newfoundland.  Masters thesis, Memorial University of Newfoundland.

abstract:
Coastal embayments of Newfoundland are key spawning and nursery areas for
numerous socioeconomically and ecologically important fish species. Survival during the
vulnerable larval stage regulates recruitment and adult population dynamics. Larval fish
community structure and larval capelin population dynamics were examined over two
years in two relatively unstudied northern coastal embayments of Newfoundland (White
Bay and Notre Dame Bay) and compared to that of Trinity Bay. Differences in
community structure were driven primarily by sampling month, with no significant
differences observed between years and among bays. However, larval capelin otolith
microstructure analyses revealed that growth was significantly higher in the northern bays
in 2015, but lower in 2016, relative to Trinity Bay. This research suggests that seasonally
driven larval fish community structure is consistent along much of the Northeast coast of
Newfoundland, while larval capelin dynamics vary spatially, and these spatial differences
in growth and abundance may vary substantially on an interannual basis.


identifier: Bégin, Daniel <https://research.library.mun.ca/view/creator_az/B=E9gin=3ADaniel=3A=3A.html>   (2018) Life and death of volunteered geographic information contributors in a large online community - the case of OpenStreetMap.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
The advent of the Web 2.0 has democratized both the production and dissemination of knowledge by enabling communities of online contributors to generate content collectively. This thesis focuses on “Volunteered Geographic Information” (VGI), a type of user-generated content (UGC) oriented toward geographic information. The provided content is known to be highly heterogeneous in coverage, nature and quality, reflecting a patchwork of motivations, interests, knowledge and skills of individual contributors. Characterizing VGI data requires understanding contributors’ behaviour. Typologies of contributors are proposed in an attempt to link VGI contributors with the nature of the data they provide. Those typologies are directly or indirectly related to the time spent by the contributors in a project, but they do not use a formal temporal perspective to understand their behaviour. We considered the time spent by contributors in a given VGI project as an essential component for understanding their contribution patterns (e.g. volume, content, quality).
In order to fill this knowledge gap regarding how the time in the project may have impacted contributors’ behaviors, I analyzed the behaviour of the OpenStreetMap (OSM) contributors, of a large VGI community. I identified different events that affected enrollments and withdrawals over a project’s history using time series analyses. I established the phases of contributors’ life cycle using survival analyses and linked their contributions to the different phases.
Six distinct phases were identified in the life cycle of OSM contributors. Analyses revealed that these phases were grouped into three major stages: An “Assessment” stage that last a few months, followed by an “Engagement” stage that can extend over more than a decade, to eventually move to a “Detachment” stage over which the contributors leave the project. Analysis of contributions at each phase revealed that contributors’ behaviour is dominated by two distinct processes. When contributors enroll in a project, they seem to be driven by a learning-adaptation-dominated process before switching to a cumulative-damage-dominated process followed by a withdrawal from the project. In parallel, I found that the diffusion of innovation theory (DoIT) had an important impact all along the project’s history. This research not only shed light on online contributions but also reveals different aspects of human behaviours.


identifier: Butler, Erika D. <https://research.library.mun.ca/view/creator_az/Butler=3AErika_D=2E=3A=3A.html>   (2018) Iron amino-phenolate complexes as catalysts for CO₂ activation.  Masters thesis, Memorial University of Newfoundland.

abstract:
The increase of CO₂ emissions in the atmosphere from the burning of fossil fuels has been linked to global climate change. Therefore, finding methods to utilize CO₂, a greenhouse gas, as a C1 feedstock has become of interest. The utilization of CO₂ is beneficial as it is an inexpensive, abundan feedstock with low toxicity, and it can react with epoxides to produce polycarbonates or cyclic carbonates; both of which have several applications. Cyclic carbonates can act as polar aprotic green solvents as well as chemical intermediates for the synthesis of other small molecules and polymers, while polycarbonates can be used to synthesize several biodegradable plastics. Using iron to catalyze these reactions has its own benefits as iron is inexpensive, abundant, and biocompatible.
Both the formation of cyclic carbonates and polycarbonates was carried out using iron(III) amino-bis(phenolate) complexes. The iron(III) complexes were characterized by UV-vis spectroscopy, MALDI-TOF MS, and elemental analysis. These complexes were capable of selectively producing cyclic carbonate from carbon dioxide and several epoxides, and reaction parameters could be fine tuned to reduce temperature and reaction time. Polycarbonates were also synthesized selectivity from CO₂ and cyclohexene oxide (CHO) in high yields with moderate molecular weights and low dispersities. Polycarbonate synthesis could be carried out at low pressures and temperatures, which is not common for iron catalyst systems. Isolated polymers were studied further using NMR spectroscopy, GPC analysis, and MALDI-TOF MS.


identifier: MacDonald, Shamus Y. <https://research.library.mun.ca/view/creator_az/MacDonald=3AShamus_Y=2E=3A=3A.html>   (2017) “Dh’fheumadh iad àit’ a dheanamh” (They would have to make a Place): land and belonging in Gaelic Nova Scotia.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
This thesis explores the way land has been perceived, described and experienced by Scottish
Gaels in Nova Scotia. It examines how attitudes towards land are maintained and perpetuated
through oral traditions and how oral history, legends and place names have fostered a sense of
belonging in an adopted environment. Drawing on archival research and contemporary
ethnographic fieldwork in Gaelic and English, it explores how people give anonymous aspects of
the natural and built environment meaning, how personal and cultural significance is attached to
landscapes, and how oral traditions contribute to a sense of place.
Exploring a largely unofficial tradition, my thesis includes a survey of Gaelic place
names in Nova Scotia that shows how settlers and their descendants have interpreted their
surroundings and instilled them with a sense of Gaelic identity. It also considers local traditions
about emigration and settlement, reflecting on the messages these stories convey to modern
residents and how they are used to construct an image of the past that is acceptable to the
present.
Given its focus on land, this work investigates the protective attitude towards property
long ascribed to Highland Gaels in the province, considering local perspectives of this claim and
evaluating its origins. It also examines the personal and cultural impact of social stratification
based on land in the region, namely between properties located along the shore and those in the
backlands. Providing a more holistic understanding of rural depopulation, my thesis challenges
romantic views that frame out-migration as a symptom of cultural wanderlust, demonstrating
connections to linguistic and cultural loss and making clear the continued importance land plays
in the lives of those who moved away. Taken together, this material explores the complex and
highly developed connection to land expressed by Gaels in Nova Scotia and provides a case
study of how an immigrant group can invest a landscape with meaning over time.


identifier: Rayner, Gemma <https://research.library.mun.ca/view/creator_az/Rayner=3AGemma=3A=3A.html>   (2018) The behavioural interactions between the American lobster (Homarus americanus) and the invasive green crab (Carcinus maenas).  Masters thesis, Memorial University of Newfoundland.

abstract: The American lobster (Homarus americanus) is the most commercially important decapod species in Newfoundland. Since the 1990s, fishery landings in Placentia Bay, Newfoundland have been steadily decreasing. The invasive green crab (Carcinus maenas) was first recorded in North Harbour (Placentia Bay) most likely in 2002, and shortly after this, lobster landings decreased by 34% compared to previous years. Analyses of the behavioural interactions between the two species around a food source and a baited trap were used to better understand the potential impacts of green crabs on lobsters in the natural environment. The presence of green crabs (1-25 animals) had no significant effect on the ability of lobsters to acquire food, but they did negatively impact lobster food consumption when present in high numbers (150 crabs). Agonistic interactions between the two species increased with green crab density. Green crabs also significantly affected lobster behaviour around a baited trap; when green crabs were present and could freely move around the trap, a lobster approached, attempted to enter and successfully entered less frequently compared to trials when no crabs were present. Analyses of predator-prey interactions between adult lobsters and green crabs were also used to determine if lobsters from Newfoundland would recognise green crabs as a potential prey item. Lobsters originating from Nova Scotia and Newfoundland actively consumed green crabs of all sizes and the size of the green crab determined the likelihood of being damaged and consumed by a lobster. The longer a green crab remained in the presence of a lobster, the more likely it would be captured and eaten. This research provides information on the potential impact of green crab on the lobster fishery in Newfoundland and Labrador and may be used by stakeholders in the management this fishery.


identifier: Zurgani, Mohamed Abdulhakim <https://research.library.mun.ca/view/creator_az/Zurgani=3AMohamed_Abdulhakim=3A=3A.html>   (2018) Flexural behaviour of high strength steel fibre normal and lightweight concrete beams.  Masters thesis, Memorial University of Newfoundland.

abstract:
An experimental study was conducted to investigate the flexural behaviour of high strength normal and lightweight reinforced concrete beams with steel fibres. Three different mixtures were developed for each type of concrete with three different steel fibre volume ratios. The target compressive strength was 85 MPa. Material and structural experimental programs were performed. In the material investigation, twenty four prisms with dimensions of 100 mm × 100 mm × 400 mm and one hundred and twenty cylinders with dimensions of 100 mm × 200 mm were cast, cured and tested to determine the mechanical properties for all different mixtures. The investigated mechanical properties included the compressive strength, splitting tensile strength, modulus of rupture and flexural toughness.
In the structural investigation, a series of six high strength lightweight aggregate (LWAC) concrete reinforced beams and six high strength normal weight (NWC) reinforced concrete beams were cast and tested. The beams were 200 mm × 400 mm × 3200 mm and were simply supported on a clear span of 2900 mm. The main variables in this study were the concrete type (normal weight concrete and light weight aggregate concrete), steel fibre volume ratio, (0 %, 0.375%, 0.75%), and the longitudinal reinforcement ratio, (0.85%, 1.50%). The structural behaviour of the test beams was examined in terms of load-deflection behaviour, steel reinforcement strain, concrete strain, crack pattern, crack width, crack spacing, mode of failure and ultimate moment capacity.
The test results revealed that the addition of steel fibres to high strength lightweight or normal weight concrete improved the mechanical properties. The compressive strength, splitting tensile strength and the modulus of rupture of fibrous LWAC and NWC concrete increased compared to the plain concrete.
Adding steel fibre to both high strength normal and lightweight concrete increased both cracked and un-cracked stiffness in addition to increasing the ultimate flexural capacity. The steel fibres also enhanced the cracking behaviour for both NWC and LWAC beams, reduced the crack widths and increased the number of the cracks for both type of concrete. The LWAC beams developed more cracks but less cracks width compared to their identical NWC beams. The ductility indexes of fibrous and non-fibrous NWC beams were higher than the ductility indexes measured for the corresponding LWAC beams.
For all fibre reinforced NWC and LWAC beams, CSA A23.3-14, ACI 318-08, EC2-04, and EC2-91 codes overestimated the maximum crack width due to the fact that these models do not consider the presence of steel fibres. The Rilem TC162-TDF was found to accurately predict the maximum crack width of fibrous NWC beams. However, the model was seen to be conservative when predicting the maximum crack width for fibrous LWAC beams.


identifier: Masrob, Mohamed Ali <https://research.library.mun.ca/view/creator_az/Masrob=3AMohamed_Ali=3A=3A.html>   (2018) A smart power system stabilizer for dynamic reduction of a power system model.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
This thesis focuses on studying the dynamic stability of power systems and improving them by the addition of smart power system stabilizers (PSSs). A conventional design technique of a power system stabilizer that uses a single machine connected to an infinite bus through a transmission line (SMIB) has been widely used for study of elecromechanical perturbations. This approach requires estimating the external equivalent impedance and the voltage at an external bus for each machine in a multi-machine system.
This study will use the conventional mathematical method, which represents a power system with some modifications. The dynamic model is linearized by taking the high voltage side on the generation unit as a reference instead of the infinite bus voltage. By using this modification, several improvements are accomplished, the main ones of which are: the estimation of states is eliminated, the time consumed in estimating calculations is reduced, the parameters of the model are independent of the external system, and the PSS design for each machine is independent in a multi-machine environment system. This strategy enables a PSS to be designed for a single machine and then implemented in a multi-machine system.
Power systems have advanced to the point that they now cover vast geographical areas. Consequently, they are not only quite complicated, but the system orders are also high. As the complexity of these systems increases, so does the difficulty of examining their dynamic stability and adjusting their controllers. In this research, to address these issues, the reduced model technique has been employed to mathematically define smaller system models from existing models, such that the properties of both systems are comparable properties.
The parameters of the PSS are determined based on a modified Heffron- Phillips model of the power system at certain operating conditions where it can provide reliable performance. Since the power systems are highly nonlinear with configurations and parameters that change with time, a typical PSS design, which is based on a linearized model of the power system, cannot guarantee its performance in practical operating environments. The present study attempts to overcome this limitation by implementing smart power system stabilizers. In the context of this thesis the word smart means novel technique.
An artificial neural network power system stabilizer (ANN-PSS), a novel multi input fuzzy logic power system stabilizer (FLPSS), and a modified multi-resolution proportional-integral-derivative power system stabilizer (MMR-PID-PSS), based on the dynamic reduction of a power system model. These PSSs have been developed to refine the power system dynamic performance by adjusting the regulator’s parameters in real-time simulation under various operating conditions.
In the first part of this research, the digital simulations results using the proposed ANN-PSS and FLPSS are carried out on a single machine connected to a network and are then compared with conventional Lead-Lag PSS. The results show that the power system with FLPSS has a better dynamic response over a wide range of operating conditions and parameter changes. Next, the digital simulations results using the proposed MMR-PID-PSS is carried out on a single machine connected to the network, a 4-machine 10-bus power system, and a 10-machine 39-bus power system and then compared with FLPSS. The results validate the effectiveness of the proposed MMR-PID-PSS regarding reduced overshoot, undershoot, and settling time under a different type of disturbances.


identifier: Minka, Eric <https://research.library.mun.ca/view/creator_az/Minka=3AEric=3A=3A.html>   (2018) A voice was heard in Ramah: the uncontrollable and uncomfortable tears of Black parents as they navigate complex parenting rules and processes in Toronto.  Masters thesis, Memorial University of Newfoundland.

abstract: Where children grow up has a major impact on what they become as adults. Towards achieving what is optimal for one’s children, parents across cultures carry out different parenting practices. Despite this, Black parents in Canada feel their parenting practices are unfairly targeted by Child Welfare Agencies (CWA), resulting in the overrepresentation of Black children in the welfare system. This thesis presents qualitative findings on Black parents’ knowledge, perceptions, and experiences of navigating through complex Child protection rules and processes in Toronto, Canada. Results revealed that Black parenting experiences are shaped and influenced by cultural knowledge and perceived anti-Black racism in Canada, yet CWA hardly consider this information in their engagements with Black families. Further, most participants had negative perceptions of CWA as people who disunite families and racially target Black families. The study reifies that CWA need to take necessary steps to understand the complex contexts of Black parenting.


identifier: Soliman, Ahmed <https://research.library.mun.ca/view/creator_az/Soliman=3AAhmed=3A=3A.html>   (2018) Automated hand hygiene monitoring system using imagery and bluetooth low energy sensors.  Masters thesis, Memorial University of Newfoundland.

abstract:
This thesis designs and implements a hand hygiene monitoring system using Bluetooth low
energy and imagery sensors. As the cost of treating healthcare-associated infections
increases, the need for monitoring and improving hand hygiene compliance percentages
for healthcare providers increases. Several techniques for hand hygiene compliance
monitoring exist, but it was found that electronic automated systems are the most reliable
solution because they provide more accurate continuous compliance measurements for
lower cost. Other similar systems based on a variety of technologies exist, however, they
are either uniquely evidence based, so that they capture hygiene moments and apply a
statistical model for hygiene opportunities, and they, therefore, do not provide real-time
information; or they require human interference to determine compliance rendering them
not fully automated. In this thesis, available monitoring techniques, focusing on automated
electronic systems, are first introduced. Then, a novel automated hand hygiene monitoring
system, capable of capturing hygiene moments with more than 90% precision, is proposed.
The proposed system was first tested in a lab environment with private rooms setup, the
system was also tested in semi-private rooms setup and then implemented in the
Hematology and Oncology Department at the Health Sciences Center of Eastern Health for
a pilot study. The study showed a high correlation between the compliance rates calculated
by the proposed system compared to the compliance rates found by direct observers.


identifier: Al-Jabea, Ibrahem <https://research.library.mun.ca/view/creator_az/Al-Jabea=3AIbrahem=3A=3A.html>   (2018) Equivariant cohomology and GKM-sheaves.  Masters thesis, Memorial University of Newfoundland.

title: Equivariant cohomology and GKM-sheaves

abstract:
If a topological group T acts on a topological space X, we may define the equivariant
cohomology ring H*T(X). Due to its importance, several techniques have been developed
to study equivariant cohomology. Goresky, Kottwitz, and MacPherson proved
that of T torus action with a certain condition (GKM-manifold) the equivariant cohomology
ring H*T(X) has a combinatorial description. More recently, T. Baird applied
GKM-methods to general equivariantly formal compact T-manifold X. He developed
a new class of sheaves (GKM-sheaves), and proved that the equivariant cohomology of
X is isomorphic to the global sections of a GKM-sheaf FX. The purpose of this thesis
is studying the GKM-theory and GKM-sheaves. In particular, we study the higher
cohomology of GKM-sheaves and generalize the theory to compact T-manifolds for which H*T(X) is reflexive.


identifier: Alruhaymi, Maryam <https://research.library.mun.ca/view/creator_az/Alruhaymi=3AMaryam=3A=3A.html>   (2018) Ultrasound imaging operation capture and image analysis for speckle noise reduction and detection of shadows.  Masters thesis, Memorial University of Newfoundland.

abstract:
Ultrasound is becoming increasingly important in medicine, both as a diagnostic tool
and as a therapeutic modality. At present, experienced sonographers observe trainees
as they generate hundreds of images, constantly providing them feedback and eventually
deciding if they have the appropriate skills and knowledge to perform ultrasound
independently.
This research seeks to advance towards developing an automated system capable of
assessing the motion of an ultrasound transducer and differentiate between a novice,
an intermediate and an expert sonographer. The research in this thesis synchronizes
the ultrasound images with three depth sensors (Microsoft Kinect) placed on the top,
left and right side of the patient to ensure the visibility of the ultrasound probe.
Videos obtained from the three categories of sonographers are manually labeled and
compared using Studiocode Development Environment to complete the items on the
medical form checklist.
Next, this thesis investigates and applies well known techniques used to smooth and
suppress speckle noise in ultrasound images by using quality metrics to test their
performance and show the benefits each one can contribute. Finally, this thesis investigates
the problem of shadow detection in ultrasound imaging and proposes to detect shadows automatically with an ultrasound confidence map using a random
walks algorithm. The results show that the proposed algorithm achieves an accuracy
of automatic detection of up to 85%, based on both the expert and manual
segmentation.


identifier: Rashid, Mohammad Mamun Ur <https://research.library.mun.ca/view/creator_az/Rashid=3AMohammad_Mamun_Ur=3A=3A.html>   (2018) Development of a modified material balance equation for complex reservoirs with the inclusion of fluid velocity.  Masters thesis, Memorial University of Newfoundland.

abstract:
Material Balance Equation (MBE) is among the most widely used techniques to estimate the
reserve of any types of hydrocarbon reservoir. Complex reservoirs, such as fractured oil
reservoir and shale gas reservoir have been recognized as a potential energy sources where a
substantial amount of reserve are trapped. Modified MBE for complex reservoir enhances the
accuracy and assists production engineers to take a proper decision regarding the selection of
the recovery techniques. The one of the aims of this study is to review the existing knowledge
and find out the significant gap in previous research on numerous recently developed material
balance equation. The central goal of this work is to develop two modified MBE for the
mentioned reservoir types. These equations include the velocity of the fluid and other rocks
and fluid properties: viscosity, permeability and length of the reservoir. The results showed
that incorporating the velocity and other fluid properties increases the recovery of the reserves.
An important factor to derive an MBE is effective compressibility which is ultimately
influenced by fluid velocity, viscosity and permeability. A sensitivity analysis has been
conducted that shows the influence of the change of these properties on effective
compressibility. Performing reserve estimation procedure without shut in is a big challenge for
the production engineer. No researcher has introduced any parameter of fluid velocity in MBE
which are so far reviewed in this study. Because of the absence of velocity in the established
MBE, production is needed to be shut in to estimate the reserve. The developed material
balance model includes this important velocity term which enhances the recovery of reserves
and allows to calculate the reserve without shut in. The results of the modelling and sensitivity
analysis can be a future guideline to develop an impressive material balance model for fractured
reservoir.


identifier: Bisnaire, Alexandre Charest <https://research.library.mun.ca/view/creator_az/Bisnaire=3AAlexandre_Charest=3A=3A.html>   (2018) Oceanic redox conditions across the Cambrian-Ordovician boundary.  Masters thesis, Memorial University of Newfoundland.

abstract:
Trace element and isotope geochemistry is used to evaluate paleoenvironments.
Uranium and molybdenum geochemistry in particular have been used as reliable
paleoredox indicators, leading to valuable developments. Here, these proxies are applied
to the transgressive sedimentary succession spanning the Cambrian ‒ Ordovician GSSP
boundary section of the Cow Head Group exposed at Green Point, western
Newfoundland (Canada).
In Chapter 2, the distal slope environment of deposition is evaluated based on the
green to black shales’ geochemistry. It underwent significant changes during the
transgression occurring around the Cambrian-Ordovician boundary. As the platform
became increasingly flooded and more carbonate-dominated, the cratonic siliciclastic
supply decreased, lowering the proportion of Al (6.2±1.1 wt% to 5.2±1.0 wt%), Cr
(64±12 ppm to 55±10 ppm), Sc (9.1±1.8 ppm to 7.5±1.6 ppm), Th (7.4±1.2 ppm to
5.9±1.4 ppm) and Cs (3.7±1.0 ppm to 2.6±0.8 ppm) and increasing the proportion of Ca
(3.8±3.0 wt% to 4.8±2.8 wt%) in the shales. Conditions became more reducing as
relative sea level rose, becoming more strongly suboxic, with more frequent anoxic
intervals. Due to short-term fluctuations (reflected in the highly variable lithology), this
is reflected most accurately by the higher proportion of shales demonstrating significant
U and Mo authigenic enrichment above the anomaly level, and their relationship to
higher TOC values. Bioproductivity was low throughout the section, based on low P (494±141 ppm), Ni (32.8±10.5 ppm) and Cu (36.1±16.8 ppm). Bioproductivity variation
across the anomaly level could not be ascertained however. The geochemical patterns
observed correlate well with the carbonate carbon isotope stratigraphy, clearly defining
trends and systems tract.
In Chapter 3, we focus on Mo and U elemental and isotopic geochemistry. We first
evaluate the relationship of U/Mo ratio vs U and Mo (both concentrations and EFs) in the
Green Point shales and compare the results to several modern and Phanerozoic-aged
siliciclastic environments to evaluate repeatability and predictability. Secondly, this
method is applied to the Green Point carbonates and modern Bahamas carbonates. In the
third part of this chapter, we focus on the δ⁹⁸Mo ratios from the Green Point carbonates
and their reliability as a predictive paleoredox tool. Uranium and Molybdenum were
found to have divergent relationships to the U/Mo ratios. In the Green Point shales, the
relationship between U/Moauth vs MoEF or UEF enrichment factors were found to be
reliable redox indicators, particularly U/Moauth vs MoEF. When applied to other
siliciclastic datasets, plotting U/Moauth to MoEF or UEF yielded a different yet consistent
pattern relative to the UEF vs MoEF plot of Algeo and Tribovillard (2009), differentiating
oxygen levels, most notably within the suboxic range, and marine basin restriction.
Within the carbonates, the main factor controlling the low U concentrations was calcite
being the carbonate species present. The decrease across the anomaly is likely due to the
TOC decrease; enhanced by low dissolved porewater sulfide levels and the presence of
carbonate material. The positive U/Mo vs U trend supports the conclusion that authigenic enrichment was not tot the main control on observed variations. The Mo
values were within the range of previously carbonates, indicating pH and carbonate
species present may not affect Mo enrichment. The U/Mo vs Mo plot behaved like in the
shales, showing potential as a redox indicator. When applied to the Bahamas carbonates,
both relationships consistently differentiated low and high pore-water sulfide levels, and
shows potential to differentiate paleoenvironments. The Mo isotope ratios were
interpreted as being a mixed detrital-authigenic signature, and so are minimum values.
The increase across the anomaly level suggests increasingly reducing conditions during
the deposition of the Green Point carbonates. This agrees with previous interpretations,
indicating δ⁹⁸Mo ratios are reliable at Green Point.


identifier: Gauthier, Matt <https://research.library.mun.ca/view/creator_az/Gauthier=3AMatt=3A=3A.html>   (2018) Wave-assisted propulsion for autonomous surface vehicles.  Masters thesis, Memorial University of Newfoundland.

abstract:
Renewable energies, such as solar and wind, have been employed in the recent past to
power and propel unmanned marine vehicles. In most cases however, the possibility of
using wave energy is not considered. Therefore, in this thesis project, the thrust generating
capacity of an oscillating hydrofoil in head seas is investigated. A mathematical
model is presented that computes the forces on a two-dimensional hydrofoil oscillating
in pitch. Existing empirical force coefficients are used to estimate the horizontal and
vertical forces generated by the hydrofoil based on the effective angle of attack. A
simulation case is then developed in OpenFOAM enabling the effects of wave height,
wave frequency, foil pitch amplitude, and forward speed to be studied. To evaluate
theoretical and simulation results, a hydrodynamic testing platform is developed using
a DC motor to actuate the foil and a four load cell arrangement to measure forces. The
experiments are performed in the wave tank of Memorial University of Newfoundland.
Design of experiments methodologies are used to develop regression equations for
simulated and physical data. A comparison of both model equations reveals that the
simulation model is slightly offset from the physical model; however both models show
that thrust can be achieved in head seas by using an actively pitch-controlled hydrofoil
in low current conditions.


identifier: Sanguinetti, Tomas <https://research.library.mun.ca/view/creator_az/Sanguinetti=3ATomas=3A=3A.html>   (2017) Reaching livability: designing accessible cities for all.  Masters thesis, Memorial University of Newfoundland.

abstract: While sustainability dominates the discourse in urban theory and practice, a growing literature has recognized the importance of liveability in city-making. Livability is the sum of factors that contribute to a city's quality of life. One significant factor is access to services and goods for pedestrians, an aspect of planning that scholars and planners have long neglected. Accessible amenities fulfil a city’s function and are an essential component of ‘good urban form’: a material and ethical morphology of the city that privileges compactness and mixed land uses to integrate amenities and people. Cities around the world, especially those in North America, face challenges that stem from sprawling urban forms. As a result, constrains to access for the pedestrian abound. Importantly, this phenomenon exists beyond global and globalizing cities. Indeed, while the literature focuses on larger cities, there is an increasing need to explore and understand the fate of medium and smaller cities. This study contributes to the small city scholarship by offering a descriptive assessment of access to amenities in a mid-size Canadian city, St. John’s (NL), through an analysis of census and business microdata between 2006 and 2010. I argue that given St. John’s urban form (low-density, disconnected streets, low mix use, car-friendly), access to amenities is low across the metropolitan region. My findings have several significant results: first, the average minimum distances to amenities exceed the established walking standard of 500m across the St. John’s metropolitan area; second, there is a mismatch of population to amenity across the region; third, vulnerable demographic groups like the young and the elderly who are in higher need of amenities typically enjoy better access than others; and fourth, accessibility is better where urban form is more compact. Finally, I conclude that accessibility in St. John's is spatially unequal, but fairly equitable, and that areas with higher accessibility are concentrated in old City of St. John's.


identifier: Tong, Jinjun <https://research.library.mun.ca/view/creator_az/Tong=3AJinjun=3A=3A.html>   (2018) Time series and state space model with generalized extreme value distributed marginals and α-stable distributed errors.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
This thesis is mainly focused on the estimation and filtering of extreme events time
series and models with generalized extreme value distributed marginals and the multiplicative
errors from α-stable distribution.
First a non-linear time series with Fréchet distributed marginals and α-stable
distributed errors is considered. To estimate the stability parameter, three recursive
procedures are proposed. The first is based on the Hill estimation, the second is a
modified Fan’s estimation that uses the property of the α-stable distribution, and the
last is an application of Kantorovich-Wasserstain metric.
For the state space model with generalized extreme value distributed marginals
and α-stable distributed errors, the estimation is more complex, especially when the
stability parameters are small. In the model with Gumbel distributed marginals, if
one of the stability parameter is known, a procedure that generates an ensemble from
the known error distribution by Monte Carlo followed by estimation is proposed. For
a model with generalized extreme value distributed marginals and unknown stability
parameters, first a recursive regression estimation is applied to obtain the generalized
extreme valued parameters, then the Yule-Walker estimation or generalized least
square regression model is used to estimate the stability parameters.
Regarding filtering, the estimation of unobserved states and their empirical conditional
densities are our interests. The estimation of states is obtained numerically
via Monte Carlo, based on the model structure. This procedure outperforms Kalman
filter. As to the empirical conditional density, sequential importance sampling with
different importance functions, particle filter with discrete sample space, auxiliary
particle filter and plain linearization are used and compared.
The asymptotic properties and rates of convergence of the proposed estimations are
studied analytically and through simulation. The methods and procedures developed
in this thesis have been applied to analyze the air pollution data in New York city.


identifier: Ramasamy, Abiraami <https://research.library.mun.ca/view/creator_az/Ramasamy=3AAbiraami=3A=3A.html>   (2018) Variability of microbial taxonomic and functional diversities across management boundaries in a boreal podzol.  Masters thesis, Memorial University of Newfoundland.

abstract:
Land capability classification describes boreal podzols as soils with severe to moderately severe
limitations that restrict the capability of the land to produce crops. Nevertheless, they are used
for crop production and it is predicted that more boreal podzols will be converted from forestry
use to agricultural uses. This usually requires intensive conservation and fertility improvement
practices aimed at correcting the excessively low pH and improving soil carbon parameters.
Under such management, it is expected that the biotic parameters and drivers of soil fertility
would be drastically affected. It is hypothesized that mass and energy fluxes across the edge of a
cropped field, between natural and managed conditions of soil, will alter the diversity of
microbial populations and their fertility relevant functions.
To verify this, I surveyed a cropped field and its immediate surrounding areas, located within a
Boreal Forest Ecosystem in Western Newfoundland. The surrounding areas, outside the four
field edges covered four distinct non-cropped conditions, i.e. forested, wetland, grassland and
grassed farm road border. Bacterial taxonomic diversity was assessed via a 16S rRNA obtained
through an Illumina MiSeq PE 250bp amplicon sequencing of the V4 hypervariable region.
Fungal taxonomic diversity was assessed on an ITS dataset obtained through an Illumina MiSeq
PE 250bp amplicon sequencing of the ITS1-2 region. A predictive functional profiling of the
bacterial community, based on the 16S rRNA results (PICRUSt) was then carried out. Results are
contextualized by standard abiotic soil parameters and compared to potential nitrogen mineralization rates
along a management intensity gradient, i.e. a gradient crossing from natural to cropped conditions. Both
surface and subsurface layers were considered. Standard and exploratory statistics were carried out and
included an analysis of ecological indicators for population diversity. Statistical analysis was carried out
separately on soil physicochemical properties, microbial taxonomic diversity, and microbial functional
diversity. Correlational analyses between microbial diversity and physicochemical properties and were
carried out separately. It was found that, while the natural conditions tested had distinct diversities, the
results became increasingly similar towards the field centre, away from the natural edge. Thus, land
management affects the taxonomic and functional diversity of microorganisms and also found
that the shift in taxonomic and functional diversity is directly related to the distance from the
natural areas.


identifier: Comeau, Emilie M. <https://research.library.mun.ca/view/creator_az/Comeau=3AEmilie_M=2E=3A=3A.html>   (2018) Effect of NKG2C absence on natural killer cell phenotype and function in human immunodeficiency virus/cytomegalovirus co-infection.  Masters thesis, Memorial University of Newfoundland.

abstract: Natural killer (NK) cells expressing NKG2C and CD57 expand following human cytomegalovirus (CMV) infection. This NK cell subset downregulates FcεR1γ and acquires enhanced capacity to mediate antibody-dependent cellular cytotoxicity (ADCC). Expansion of these differentiated NK cells is exaggerated in human immunodeficiency virus (HIV) infection. Individuals lacking the gene encoding NKG2C have diminished resistance to HIV, but it remains unclear whether differentiation into NK cells with superior ADCC is impaired in NKG2Cnull individuals. Therefore, our objective was to investigate if CMV-driven NK cell differentiation into enhanced killers is impaired in NKG2Cnull HIV-infected individuals. Phenotypic (CD57⁺, FcεR1γ⁻) and functional (IFN-γ, TNF-α induction and cytotoxicity) NK cell responses were compared between NKG2Cnull and matched NKG2C-expressing individuals by flow cytometry following stimulation through natural cytotoxicity receptors (using K562 cells) or CD16 (using monoclonal antibody, 3G8). Cytotoxicity was measured in ⁵¹Chromium release assays against anti-CD16-coated P815 cells (redirected lysis) and anti-human leukocyte antigen (HLA) class I antibody-coated C1R cells (classical ADCC). Antibodies were titrated to determine concentrations producing half maximal responses (EC₅₀) to compare sensitivity. Our data indicate highly similar CMV-driven NK cell differentiation in terms of both general phenotype and function, regardless of NKG2C genotype. The observed equivalency between groups suggests alternate routes of CMV-driven NK cell differentiation, which are independent of NKG2C.


identifier: Razavi, Haniyesadat <https://research.library.mun.ca/view/creator_az/Razavi=3AHaniyesadat=3A=3A.html>   (2018) Using guided data collection to improve the quality of citizen science user-generated content.  Masters thesis, Memorial University of Newfoundland.

abstract: With the advent of Web 2.0, there has been tremendous growth in User-Generated Content (UGC), wherein members of the general public participate in contributing information online. Citizen science is a popular form of UGC in which participants support scientific data collection or analysis. However, in projects that rely on citizens to contribute data, obtaining data that is of sufficient quality to be useful for research is challenging. Among the challenges in obtaining data are: lack of control over the content of data supplied; lack of incentive to contribute; and lack of system flexibility to capture unanticipated data. Any of these challenges may lead to low-quality data that might not be useful in scientific research. Improving the data collection phase in online citizen science may facilitate capturing higher quality data. The primary purpose of this research is to propose and evaluate guidance features to support data entry to increase the quality of data collected. An experiment under three different conditions was conducted based on a citizen science project in the biology domain. Three types of guidance were tested to determine which is more effective in assisting the contributors in species identification (a widely used level of classification that is useful in biology research). The results demonstrate that using a guidance feature assists contributors in identifying species. Moreover, the guidance enables contributors to provide data of better quality in terms of relevance and objectivity. This thesis concludes by summarizing implications and provides suggestions for future study.


identifier: Savoie, Judith <https://research.library.mun.ca/view/creator_az/Savoie=3AJudith=3A=3A.html>   (2018) Utility assessment of otolith microchemistry for salmon fishery management and MP-AES analytical system for food safety in Lake Melville, Labrador.  Masters thesis, Memorial University of Newfoundland.

abstract:
Atlantic salmon (Salmo salar) Food, Social, and Ceremonial (FSC) fishery in Lake Melville, Labrador, is an important food source for Indigenous communities living around Lake Melville. The feasibility of using analytical tools to provide information for fishery management and to enable healthcare authorities to ensure food security and safety was assessed in this thesis. First, the feasibility of using otolith elemental concentrations as natural markers of natal river were investigated by using Na, Mg, K, Mn, Zn, Rb, Sr, and Ba concentrations in juvenile and adult salmon. Juvenile salmon were sampled in 11 watersheds flowing into Lake Melville, while adult salmon samples were collected from the FSC fishery. Discrete juvenile otolith elemental composition among watersheds was demonstrated by linear discriminant function analysis, reassigning juveniles accurately to their natal river 89 % (range 73 % - 100 %) of the time on average. Natal river of adults was inferred based on the juvenile dataset. Most of the adult salmon were assigned to the Kenamu River, but the assignment performances seemed to be limited by the interannual and spatial variability of the natal rivers’ chemistry. The results obtained demonstrated that the use of otolith microchemistry as a tool for providing information on natal river for fishery management and ensure food security in Lake Melville is promising but further research is required.
Second, the feasibility of using microwave plasma-atomic emission spectrometry (MP-AES) to quantify mercury at low concentrations in Lake Melville salmon muscle tissue was assessed. The method developed was validated by using certified reference material (DORM-3) and by mercury quantification of the salmon tissue performed by an accredited laboratory using cold vapor-atomic fluorescence spectrometry (CV-AFS) and by MP-AES. Mercury concentrations quantified by MP-AES were not significantly different than those obtained by an accredited laboratory, indicating that MP-AES can accurately quantify mercury. The MP-AES limit of detection (0.005 μg g⁻¹ wet weight) is well below the mercury consumption limit (0.2 μg g⁻¹ wet weight) recommended by Health Canada for FSC fisheries. Our results also demonstrated that the Atlantic salmon in Lake Melville are safe to consume (range 0.04 – 0.07 μg g⁻¹ wet weight) and will serve as references for monitoring this fishery after the impoundment of Muskrat Falls. Finally, we concluded that MP-AES is a suitable analytical system for mercury quantification to assess and monitor food safety.


identifier: Bagum, Monuara <https://research.library.mun.ca/view/creator_az/Bagum=3AMonuara=3A=3A.html>   (2018) Development of an environmentally safe additive with natural material for drilling fluid application.  Masters thesis, Memorial University of Newfoundland.

abstract: Efficient and optimistic drilling operations depend on a number of parameters such as drilling fluid (DF) additives. Present demands of DF and future challenges have prompted researchers to develop environmentally-friendly drilling fluids with minimum impact on the environment. Aloe Vera does not contain any toxic compound; it has been used in cosmetic and medicine for thousands of years because of its medicinal value. The present investigation leads toward the development of an environmentally-friendly mud additive using Aloe Vera instead of chemical compound. The elemental analysis of Aloe Vera is conducted using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). A particle distribution test is conducted to determine the particle sizes of the Aloe Vera sample. Complete rheological tests and filtration tests of the different concentrations of mud additives are performed to investigate the feasibility of this new additive. Particle size distribution (PSD) helps to determine the proper size of the sample so that the fluid loss, cutting collection and formation damage can be quantified. The compositional test confirms the presence of containing elements. The four representative recipes of the DF are formed with this additive along the base material bentonite. Rheological properties and other related investigations are carried out with different sizes of the sample particle and mud preparation formula. A comparative study is performed along with other additives with respect to rheological, environmental and economic benefit. This study suggests Aloe Vera can be used as a potential DF additive that is environmentally-friendly instead of toxic chemicals. The investigation confirms the benefit of this new additive.


identifier: Mirhendi, S. Sadra <https://research.library.mun.ca/view/creator_az/Mirhendi=3AS=2E_Sadra=3A=3A.html>   (2018) Discovering Type 1 diabetes patient subgroups through integrative analysis of heterogeneous data.  Masters thesis, Memorial University of Newfoundland.

abstract:
Type 1 diabetes (T1D) is a disease in which the body immune system attacks
the β-cells. As a result, very little, or no insulin is released to control the level of
glucose in the blood. Our research investigates whether groups of patients at higher
risk for developing T1D complications can be identified by integrating demographic,
clinical and genetic data. Regarding this purpose, we explore two methods including
Generalized Low Rank Models (GLRM) and Similarity Network Fusion (SNF) to
investigate our T1D dataset and to determine groups of patients at higher risk of
developing complications related to T1D.
By applying the stated methods, we have identified groups of patients suffering
from nerve damage, high blood pressure, dyslipidemia, and thyroid diseases. This
result could be used as the basis to achieve a predictive model that could allow
patients and health-care providers to take preemptive steps to reduce the risk of
developing T1D related complications.


identifier: Zhong, Jinghan <https://research.library.mun.ca/view/creator_az/Zhong=3AJinghan=3A=3A.html>   (2016) Investigation of Bit-Rock Interaction for Rotary Drilling and Influence on Penetration Rate.  Masters thesis, Memorial University of Newfoundland.

abstract: In this thesis a comprehensive investigation of non-natural vibration on enhanced drilling performance is studied. The Drilling Technology Laboratory (DTL) at Memorial University of Newfoundland has been working on a passive Vibration Assisted Rotational Drilling (p-VARD) tool which helps to increase the drilling rate of penetration (ROP) during laboratory testing and filed work for this couple of years. It has been proven by laboratory experiments and filed work that axial vibration can play a dramatically positive role in improving drilling ROP. Meanwhile, the laboratory measurement and field trial results show that the new passive vibration tool with sensor-sub can provide compatible and accurate data to identify drill string motions including rotatory speed, bit orientation, and bit vibrations including axial, lateral, torsional vibrations and bit whirl. These raw data from each drilling experiment can supply a sufficient research basis for numerical simulation. This thesis focuses on the effect of axial vibration on polycrystalline diamond compact (PDC) bit drilling performance using Discrete Element Method (DEM) simulation and experiments with the new vibration tool. Drill-off tests were conducted in the laboratory with axial vibration on the drill string. Vibration properties were adjusted by different settings of spring compliance and dampening layers. In order to study the cutting performance of the new tool, a PFC2D (Particle Flow Code in 2 Dimensions) numerical model was developed to simulate the micro-crack generation and propagation during the drilling process in synthetic rock samples. This experimental data was used to calibrate this numerical model to real drilling situations. The analyses of the Mechanic Specific Energy (MSE), the Material Removal Rate (MRR) and the Depth of Cut (DOC) are compared with a non-vibration case to evaluate ROP and drilling efficiency. The simulations result demonstrated significant increase in drilling performance when the p-VARD tool was used in the process. Simulation results of the two types of conditions of tools were analyzed and compared in lab and field work experiment respectively. The experimental data agrees with numerical simulation results which indicate it as a promising method to simulate PDC cutter-rock interaction with DEM modelling using the new pVARD tool.


identifier: Dalton, David Raymond <https://research.library.mun.ca/view/creator_az/Dalton=3ADavid_Raymond=3A=3A.html>   (2018) On Backus average in modelling guided waves.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
This thesis is a collection of five research papers. The first two are related to the Backus
average. The second two are about guided waves. The fifth ties the two topics together.
In the first paper we derive expressions for elasticity parameters of a homogeneous
generally anisotropic medium that is long-wave-equivalent to a stack of thin generally anisotropic
layers, and examine the mathematical underpinnings of the formulation.
In the second paper we examine commutativity and noncommutativity of translational
averages over a spatial variable and rotational averages over a symmetry group at a point. In
general there is no commutativity but for weak anisotropy, which is common in near-surface
seismology, there is approximate commutativity.
In the third paper we review forward-modelling expressions for Love and quasi-Rayleigh
waves and examine the sensitivity of Love and quasi-Rayleigh waves to model parameters.
In the fourth paper we perform a Pareto Joint Inversion, using Particle Swarm Optimization,
of synthetic dispersion curve data to obtain model parameters including densities,
elasticity parameters, and layer thickness.
In the fifth paper we tie together the two topics of Backus average and guided waves
by examining the applicability of the Backus average in modelling of guided waves. As
expected, the Backus average is applicable only for low frequencies and/or thin layers and
the results become worse when there is a strong nonalternating vertical inhomogeneity with
near-surface low-velocity layers.


identifier: Kayode, Oluwadairo <https://research.library.mun.ca/view/creator_az/Kayode=3AOluwadairo=3A=3A.html>   (2018) Multilateral well modeling from compartmentalized reservoirs.  Masters thesis, Memorial University of Newfoundland.

abstract: The existence of compartmentalization in oil and gas fields have been a major industry challenge for decades. This phenomenon introduces some complexity and uncertainty in the prediction of well productivities and the overall hydrocarbon recovery factor. In the past, multiple vertical wells were drilled to increase recovery. The recent advancement of the multilateral and completions technology made multilateral wells a viable alternative to produce multiple reservoir compartments, most especially offshore. Reservoir compartments may possess a set of unique characteristics, such as average pressures, thicknesses, permeabilities, and porosity distribution. This variation in properties introduced complex dynamics in forecasting the commingled production figures and overall recovery factor from complex reservoir structures using advanced well systems. Existing analytical and semi-analytical productivity models due to the simplifying assumptions in their development are only suitable for first approximations and early estimates in field applications. In this work, a comparison is made between the more widely known finite difference numerical method and the finite volume numerical discretization method in field productivity predictions. The Matlab Reservoir Simulation Toolbox (MRST) which is a collection of open source codes, based on the finite volume discretization methodology is used to develop the reservoir compartment and multilateral well model used in this study. We investigate the pressure drop behavior over time through the lateral for a conventional well completion and compare with the pressure drop behavior for a smart well completion with downhole flow control devices for flow control and optimization. Several cases of compartmentalized reservoirs with faults of varying orientation and sealing capacity is then investigated. The production profile results obtained from the base reservoir case from MRST is compared to those from the IMEX simulator tool in CMG (Computer Modeling Group), a commercial reservoir simulator, based on the finite difference numerical discretization method. The results we obtain show a more accurate production profile prediction based on the finite volume method over the finite difference method, as expected. The ability of the simulation toolbox as well as the importance of using an improved and more efficient numerical discretization scheme in solving an increasingly complex array of reservoir structures and advanced well geometries, with multiphase fluid flow is demonstrated. Finally, an adjoint gradient – based method of optimization implemented in the toolbox is used to investigate the optimization potential of using the smart well completions versus a conventional well completion with the net present value as the objective function. Results obtained show that an investment in smart completions for the multilateral well ultimately yields a higher net cash flow and net present value over a conventional well of equivalent length designed without smart completions.


identifier: Powell, Theresa <https://research.library.mun.ca/view/creator_az/Powell=3ATheresa=3A=3A.html>   (2018) Pressing intent: printed pamphlets for James I's royal entry into London (1604).  Masters thesis, Memorial University of Newfoundland.

abstract: The royal entry of King James I to London in 1604 was a monumental event hosted by the City of London to welcome the ruler ceremoniously to his new realm. The City was primarily responsible for the planning and execution of the event for which they hired some of the foremost dramatists, poets, and artists of the period. Adorned with pageantry and spectacle, the ceremony followed the conventions of the early modern royal entry tradition. Unlike previous English entries, however, the 1604 triumph was memorialized and publicized in three separate printed pamphlets: The Magnificent Entertainment by Thomas Dekker (London: Thomas Man the Younger, 1604); B. Jon: His Part of King James, His Royall and Magnificent Entertainement by Ben Jonson (London: Edward Blount, 1604); and The Arches of Triumph by Stephen Harrison (London: John Sudbury and George Humble, 1604). Through an analysis of the textual and paratextual aspects of the three pamphlets, this thesis examines how the printed records of James I’s London entry communicated politicized messages that are reflective of each writer’s relationship with the City, the Crown, and the Court. The thesis argues that the pamphlets played an instrumental role in the authors’ self-fashioning and in the positioning of their works in the contemporary print market. Moreover, the three pamphlets together reveal the diversification of the pamphlet genre and the emergence and proliferation of new forms of print media at the beginning of the seventeenth century.


identifier: Wang, Xiaowei <https://research.library.mun.ca/view/creator_az/Wang=3AXiaowei=3A=3A.html>   (2018) Several aspects of e-waste problems---e-waste definitions, international trading patterns, and China's solutions.  Masters thesis, Memorial University of Newfoundland.

abstract:
Electrical and electronic equipment has infiltrated into every aspect of our lives, and created great waste problems. These problems have become popularized as electronic waste (e-waste) and received increasing attention both from the public and the govern-ment. This thesis concentrates on three different aspects of these problems: the definition of e-waste, the pattern of the global trade of e-waste, and China‘s e-waste problems and solutions.
Many countries‘ government documents related to e-waste have provided their own definitions of e-waste, but these definitions vary. This variety in e-waste definitions can bring significant problems (Khetriwal et al., 2011; Cantin and Bury, 2012; Milovantseva and Fitzpatrick, 2015). However, only a few researchers have focused on this area, and none of these studies have considered e-waste definitions other than the ones from the EU Directive and American states. This study collects formal e-waste definitions from countries all over the world, published in English or Chinese, and finds their differences mainly lay in two areas: 1) the approaches to defining their covered equipment; and 2) how the covered equipment becomes waste. The influences of these differences are that they determine a different overall nature of the e-waste issue in the jurisdiction where given regulations apply. Different definitions of e-waste lead to different e-waste volumes and compositions, different responsible parties, and different possible solutions. The differences show that e-waste has no natural definition, and that the e-waste problem is an indeterminate problem (Wynne, 1987).
Multiple e-waste problems have been caused by the international transfer of e-waste (BAN, 2002; Greenpeace International, 2005; Greenpeace, 2008; BAN, 2016). The second part of this research examines data from the United Nations COMTRADE database using a proxy method and analyzes the temporal pattern of the global trade of e-waste. This analysis results in three main findings: 1) the total international trade volume of at least certain types of e-waste has grown remarkably in the last 20 years, in which the summation of several of the biggest trade transactions account for the bulk of the total trade; 2) between 1996 and 2015, more than 80% of the international trade of e-waste measured by the COMTRADE data was intra-regional trade; and 3) the results of the trade data analysis can tell different stories when different categorization schemes for 'developing' and 'developed' countries are used to classify the trade data. Under the Basel Convention categorization scheme, the amount of the transfer of e-waste from developed countries to developing countries is very small, while under the World Trade Organization scheme (WTO), the volume of this type of trade is big and growing. These findings point to a broader problem than the specifics of either the Basel Convention or the WTO. It means not only the category of e-waste but also the categorization defined by the countries generate a fundamentally indeterminate waste management problem (more generally, see Wynne, 1987).
China has been famous as a global e-waste recipient with a terribly destroyed environment (Puckett and Byster, 2002; Tong and Wang 2004; Schwarzer et al., 2005; On-gondo, Willianms, and Cherrett, 2011; CNN, 2013), the second largest e-waste generator (Wei and Liu, 2012; StEP, n.d.), and the largest producer and consumer of electronic ap-pliances in the world (Chi et al., 2011). The third part of this thesis will comprehensively analyze the situation of China‘s e-waste problems and the effectiveness of China‘s policy solutions. This research finds that the volumes of e-waste generated inside China and e-waste already smuggled into China are both large and neither issue should be ignored by police makers. However, the Chinese government treats domestic e-waste and smuggled e-waste in completely different ways. For the domestic e-waste, China has successfully built a regulation system to control it. If collected under this system, China‘s formal e-waste disposal industry has the ability to dispose of more than 90% of its domestic e-waste. Even though problems still exist with this system (e.g., collection remains a prob-lem), the conclusion can still be drawn that the Chinese government has put great efforts into trying to control its domestic e-waste problem. Meanwhile, the e-waste already smuggled into China remains largely uncontrolled. China‘s policy approach toward its e-waste importation is a trade ban. This ban policy has not been replaced for nearly ten years and it appears to be not working well. This finding is supported by evidence coming from different sources. Every piece of e-waste already smuggled into China will end up in the informal e-waste disposal industry. The Chinese public as well as their government will still have to suffer environmental problems brought by this industry. The Chinese government still needs to take more actions to enforce domestic environmental laws that cover issues of environmental quality raised by the processing of e-waste already smuggled into the country.


identifier: Almasi, Seyed Mehrzad <https://research.library.mun.ca/view/creator_az/Almasi=3ASeyed_Mehrzad=3A=3A.html>   (2018) Investigation of vertex centralities in human gene-disease networks.  Masters thesis, Memorial University of Newfoundland.

abstract:
Studying associations among genes and diseases provides an important avenue for
a better understanding of genetic-related disorders, phenotypes and other complex
diseases. Research has shown that many complex human diseases cannot be attributed
to a particular gene, but a set of interacting genes. The effect of a specific
gene on multiple diseases is called pleiotropy and interactions among several genes
to contribute to a specific disease is called epistasis. In addition, many human genetic
disorders and diseases are known to be related to each other through frequently
observed co-occurrences. Studying the correlations among multiple diseases helps us
better understand the common genetic background of diseases and develop new drugs
that can treat them more effectively and avoid side effects. Meanwhile, network science
has seen an increase in applications to model complex biological systems, and
can be a powerful tool to elucidate the correlations of multiple human diseases as
well as interactions among associated genes. In this thesis, known disease-gene associations
are represented using a weighted bipartite network. Subsequently, two new
networks are extracted. One is the weighted human disease network to show the
correlations of diseases, and the other is the weighted gene network to capture the
interactions among genes. We propose two new centrality measures for the weighted
human disease network and the weighted gene network. We evaluate our centrality
measurements and compare them with the most commonly used centralities in biological
networks including degree, closeness, and betweenness. The results show that
our new centrality methods can find more important vertices since the removal of
the top-ranked vertices leads to a higher decline rate of the network efficiency. Our identified key diseases and genes hold the potential of helping better understand the
genetic background and etiologies of complex human diseases.


identifier: Turner, Joshua <https://research.library.mun.ca/view/creator_az/Turner=3AJoshua=3A=3A.html>   (2018) Constitutive behaviour of ice under compressive states of stress and its application to ice-structure interactions.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract:
In this work the multiaxial constitutive theory for the viscoelastic deformation of
ice developed by Jordaan and others is examined and modified. The microstructural
changes undergone by the material while under deformation have been modelled via
a finite collection of state variables which represent the average “damage” within
a region (originally coined to describe the degradation of mechanical components,
damage is here used to refer to any change in microstructure). The accumulation of
damage causes an enhancement in creep deformation via the process of microcracking
at low pressures, or dynamic recrystallization and pressure melting at high pressures.
The damage evolution is modelled based on Schapery’s approach, modified to include
the effects of low- and high-pressure damage separately. The damage rate is influenced
by confining pressure, axial stress, and temperature, with a pressure-temperature shift
function introduced to define the relationship between pressure and temperature.
An exploratory series of triaxial tests was carried out in the laboratory at Memorial
University; a description of the program, sample preparation, testing equipment, and
procedure are provided. These tests were designed to investigate the deformation of
ice under high shear and confining pressure. The ice samples were found to have an
upper limit to their strength, failing at a stress difference (which is equivalent to the
von Mises stress for a traditional triaxial test) of 26.0 ± 1.6 MPa. Thin sections of the
samples showed the region along the fault to be highly recrystallized. The amount of
recrystallization was found to decrease with distance from the fault line, with nearly
half of the failed sample being practically undamaged in some cases.
The role of numerous properties on ice-structure interactions have been investigated via a numerical scheme and the finite element program ABAQUS. The properties
examined include: the effect of elastic damage; the inclusion of power-law breakdown;
the implementation of a non-linear damage exponent; the effect of the highshear
elastic failure discovered in the above experiments, and; the use of a pressuretemperature
shift function for high-pressure damage.
Constant elastic properties were found to most closely resemble the results of
indentation experiments, particularly with the addition of the non-linear damage
exponent. Power-law breakdown was found to be suppressed under confining pressure,
and had little effect upon the qualitative behaviour of an ice-structure interaction.
Implementing the high-shear elastic limit of 26.0 MPa on the von Mises stress was
found to produce plastic deformation, instead of the expected viscoelastic behaviour;
the internal stress along the fault-line of a sample is likely higher by a factor of five,
leading to the discrepancy in behaviour. Applying the limit via a reduction in elastic
modulus led to results more consistent with experimental evidence.
A pressure-temperature shift function based on the process of pressure melting was
used to enhance or inhibit the accumulation of recrystallization damage; pressures at
one temperature were translated to the corresponding pressure at the reference temperature
of -10 ◦C by assuming either a constant distance from melting point or a constant
homologous temperature. The results were promising, producing the expected
differences in loading and layer development. Extension to a reference temperature
of -22 ◦C, the temperature limit for pressure melting, is worth consideration.


identifier: Chen, Jianguang <https://research.library.mun.ca/view/creator_az/Chen=3AJianguang=3A=3A.html>   (2018) Ground penetrating radar surveying and sediment coring analysis of a post-glacial lake, Eastern Newfoundland.  Masters thesis, Memorial University of Newfoundland.

abstract:
Ground penetrating radar (GPR) is a relatively newly developed high-frequency electromagnetic technique that has been widely used in the shallow subsurface investigation for the last few decades. Recently, a GPR survey of a small organic-rich post-glacial lake (Grassy Pond) in Eastern Newfoundland shows significant continuous laminations within the lake sediments in the GPR profiles. Since there have been very few GPR stratigraphy studies of lacustrine sediments, the main focus of this project is on the correlation between the sediment stratigraphy and the GPR sub-bottom profiles. Secondary interests are: to estimate the carbon content of a typical small inland lake to help assess how such bodies have contributed to the carbon budget since the last glaciation; and to investigate chemical variability within the sediments.
The work in this project includes GPR surveying, sediment coring, and sediment physical, geochemical and chronostratigraphic data acquisition, calibration and correlation. First of all, 50 and 100 MHz GPR surveys were completed on Grassy Pond when the lake surface was frozen in the winter. Bathymetric and depth-to-bedrock maps were created from the GPR profiles. Based on these two maps, a sediment distribution map was also created and this was used to choose sediment coring locations. Four sediment cores were collected by using a rod-driven piston corer, and additional GPR profiles were collected over these core locations. The cores were then scanned by a Multi-Sensor Core Logger (MSCL) to determine the physical properties. After that, the cores were sub-sampled and geochemically analyzed by ICP-OES. Selected sediment samples were also analyzed for C and N contents and isotopes, and radiocarbon dated. Lastly, the linkage was made between the geophysical and geochemical data, and a simple GPR forward model was created based on the sediment physical properties to enhance the data interpretation and correlation.
The results show that the lake sediments of Grassy Pond are highly-organic and water-rich. Forward models of EM wave reflections show that the laminated GPR reflections within the sediments are caused by variations in water content. The geochemical analysis shows that the water content is anti-correlated to the lithic elemental concentrations. Since the lithic inputs can reflect past climate changes, we suggest that paleoclimatic changes may ultimately be responsible for the laminations seen in the GPR profiles. The carbon budge of Grassy Pond is calculated based on the sediment volume and average carbon content of the sediments, and it is estimated as 29 kg/m², which is significantly higher than forest soils.
Besides these major results, one of our basal sediment samples is dated back to 8.6 radiocarbon years ago, which corresponds to the end of last glaciation in the same region of Newfoundland. The sediments of Grassy Pond are found to be highly enriched in arsenic (As) and molybdenum (Mo), likely associated with the erosion of iron oxide minerals in the surrounding land, as Grassy Pond overlies the alteration zone of a gold prospect. In the deepest sediment core, many elements show a concentration peak near 6.3k years ago when the regional climate started to become drier, and erosion rates increased.