identifier: Yuan, Wei <https://research.library.mun.ca/view/creator_az/Yuan=3AWei=3A=3A.html>   (2008) Traveling wavefronts in two biological models.  Masters thesis, Memorial University of Newfoundland.

abstract: In this thesis, we study the traveling wavefronts in two nonlinear reaction-diffusion models: a tumor growth model with contact inhibition and a volume-filling chemotaxis model. -- In Chapter 1, we first review the fundamental literature on reaction-diffusion equations, traveling wave solutions and the biological and mathematical background for the two models which we shall discuss in this thesis. -- In Chapter 2, we investigate a tumor growth model with contact inhibition. We will concentrate on the first type of tumor growth and consider a reaction-diffusion model for competition cells with nonlinear diffusion terms, modeling contact inhibition between normal and tumor cell populations for which wave propagation is usually observed in clinical data. Mathematically, based on a combination of perturbation methods, the Fredholm theory and the Banach fixed point theorem, we theoretically justify the existence of the traveling wave solution. Numerical simulations are finally illustrated to confirm our rigorous results. -- In Chapter 3, we study a volume-filling model of chemotaxis and provide a valid approach to establish the existence of traveling wavefronts via the Banach fixed point theorem. Rigorous results hold either when the chemotactic sensitivity is relatively small or when the wave speed is large. Numerical simulations are presented to illustrate the main results and comparisons of wave patterns in different parameters are demonstrated.


identifier: Yuelei, Yi <https://research.library.mun.ca/view/creator_az/Yuelei=3AYi=3A=3A.html>   (2004) R-Node method and its application in limit analysis of strip foundations.  Masters thesis, Memorial University of Newfoundland.

type: Thesis NonPeerReviewed

abstract: Limit analysis is very useful in the assessment and design of mechanical components and structures. Among the various methods for limit load estimation, approximate methods based on linear elastic finite element analyses are appealing to analysts and designers due to the conceptual insight, economy of computational effort and wide applicability. -- In this thesis, an approximate method for determining the limit loads of foundations on homogeneous and layered cohesive soils and cohesive-frictional soil is presented in detail. The results obtained for layered soils are presented as charts to be used for foundation design. This method makes use of the results of two or more linear elastic analyses. From these linear elastic analyses, load controlled locations called r-nodes are identified and limit loads are determined. The concept of r-nodes (redistribution nodes), which are akin to plastic hinge locations in a structure, forms the basis of this method. Several possible alternative ways of applying the r-node method to pressure-sensitive materials are also presented. -- The results obtained are compared with analytical results and elastic-plastic nonlinear finite element analysis results.


identifier: Yusuf, Abdulrahman Osman <https://research.library.mun.ca/view/creator_az/Yusuf=3AAbdulrahman_Osman=3A=3A.html>   (2013) The role of Islamic culture in transformative learning: perspective transformation among convert Muslims.  Masters thesis, Memorial University of Newfoundland.

abstract: The purpose of this qualitative study was to examine the perspective transformation among convert Muslims and to understand the role of Islamic culture and religious beliefs in shaping Mezirow's transformative learning. Limited research has been conducted addressing perspective transformation and religious conversion. Therefore, this study contributes to understanding the effect of culture and religious conversion on transformative learning. This study uses Mezirow's transformative learning theory as its theoretical framework. To address this purpose, the study examines how convert Muslims perceive their perspective transformation in the context of their religious conversion. Five Canadian converts were selected through a purposeful sampling procedure. Semi-structured interviews were conducted and constant comparative analyses were employed. -- The findings of this study indicate that the participants experience perspective transformation as a result of their conversion, and meaning making is a major role in the understanding of their perspective transformation. The findings also confirm that Islamic culture and religious belief plays a significant role in the participants' meaning structure changes. From the findings, it is concluded that perspective transformation in the context of Islamic religious conversion is also enduring. -- Two practical implications of this study are deduced: the first implication focuses on adult learning and secondly how religion serves as a lens through which reality is recognized and the second implication concentrates on the concept of an Islamic worldview. An Islamic worldview is one based on the concept monotheism (tawhid). Muslims are urged to unify knowledge of understanding self, the creation around oneself, and untimely God and action in order to realize this worldview. This implication is especially important because of the great interest in religious extremism and religious practice in today's world, as it has been evident in recent years that religion has been used to create radicalism views contrary to real views of religion.


identifier: Mostofi Zadeh, Shabnam <https://research.library.mun.ca/view/creator_az/Mostofi_Zadeh=3AShabnam=3A=3A.html>   (2012) Low flow frequency study for Newfoundland and Labrador.  Masters thesis, Memorial University of Newfoundland.

abstract: The objectives of this study were to quantify the characteristics of low flows in rivers of the province of Newfoundland and Labrador, and to develop equations which could be used to estimate the magnitude, frequency, duration, and spells of low flow events. These different aspects of low flows were analyzed by applying methods of flow frequency, flow duration, and flow spell analysis, respectively. Sixty hydrometric stations in the Island of Newfoundland which have more than 20 years of complete data were selected for the current low flow study. Because of the sparseness and shortness of hydrometric data in Labrador, sites with more than 15 years of data were chosen with a total of 12 stations. An L-moment based approach was applied for regional frequency analysis of annual minimum 1-day and 7-day flows for two separate homogeneous regions, Island of Newfoundland, and Labrador and it yielded prediction equations for low flows of different durations and return periods. The performance of these regional models was verified using new sets of data, and showed reliable results. Therefore, one can use these prediction models for ungauged sites in Newfoundland and Labrador. To perform regional flow duration analysis, physiographic parameters of the regions under study were regressed against quantiles of flow duration curves obtained for each hydrometric station to produce a regional model for predicting flow duration curves at any ungauged sites. Regional model of flow durations were validated successfully using a new set of data, and the results were promising. Different hydrological methodologies were applied to define flow spells for rivers in Newfoundland and Labrador, and regional models were defined to predict the annual maximum flow spell variables in Newfoundland and Labrador.


identifier: Zangeneh, Neda <https://research.library.mun.ca/view/creator_az/Zangeneh=3ANeda=3A=3A.html>   (2003) Enhanced Newmark method for seismic analysis of submarine slopes.  Masters thesis, Memorial University of Newfoundland.

abstract: Newmark method of slope displacement analysis has been extensively applied in many slope stability analyses. However, there are some limitations in Newmark method that may lead to non-conservative predictions of slope displacements. To provide more realistic predictions of slope displacements, these limitations are considered throughout the study for enhancing Newmark method. The following additions to the original Newmark method have been included in this study: 1) accounting for seismically induced excess pore water pressure build-up, 2) accounting for excess pore water pressure dissipation after the end of shaking, and 3) accounting for possibility of multiple failure surfaces. Those enhancements are briefly discussed hereafter. -- During an earthquake, non-cohesive soils may experience considerable pore water pressure build-up, which in the limit can lead to a state of zero effective stress and soil liquefaction. Therefore, in such a case, an effective stress approach should be used because a total stress analysis may give highly under-conservative results. In the present effective stress approach, the effects of excess pore water pressure and subsequent changes in soil shear strength are considered. -- Also, after the end of the strong shaking period, pore water pressure starts dissipating. Dissipation of excess pore water pressure causes the soil to regain part of its original shear strength and consequently, the yield acceleration increases and becomes positive. Therefore, in such a case, considering the effects of excess pore water pressure dissipation gives better estimation of permanent slope displacements after the end of shaking. In this study the effects of excess pore water pressure dissipation are also considered, based on the one-dimensional consolidation theory. -- In homogeneous soil deposits the displacements are usually dist1ibuted with depth. For such situation, the rigid block assumption may induce significant differences between actual and predicted slope displacements. Therefore, two moving blocks have been considered to mitigate this limitation of Newmark method. The model is able to reproduce the gradual deformation of soil with depth and therefore provide a more realistic prediction for uniform sand deposits. -- The proposed enhanced Newmark method has been implemented in a computer program.


identifier: Zeng, Zhen <https://research.library.mun.ca/view/creator_az/Zeng=3AZhen=3A=3A.html>   (2006) The language learning experiences and beliefs of Chinese teachers of English as a foreign language.  Masters thesis, Memorial University of Newfoundland.

abstract: This study explored the Language Learning Experiences (LLEs) and beliefs of six non-native speaking (NNS), English as a Foreign Language (EFL) teachers in China and looked for congruencies and inconguencies between the experiences and beliefs. Data collection involved an online questionnaire, an asynchronous focus group as well as individual online interviews over a two-month period. Interpretation of the findings relied on a grounded theory approach. Findings from both within and cross-case analyses highlighted tensions in teachers' LLEs, beliefs and in the connections between the two constructs. Four subcategories defining this core category are as follows: 1) high motivation and learner autonomy versus low confidence; 2) language experience versus lack of access to authentic materials and native-speakers; 3) communication and meaning versus grammar and accuracy; 4) personal versus national goals. The study concludes with implications for second language/EFL teaching and learning as well as for teacher education.


identifier: Zhang, Baozhong <https://research.library.mun.ca/view/creator_az/Zhang=3ABaozhong=3A=3A.html>   (2007) Synthesis of polyphenyl pyrenophanes and pyrenylene-ethynylene nanorings.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: This thesis mainly describes the application of the valence isomerization-dehydrogenation (VID) reaction in the syntheses of cyclic pyrene-containing molecules. -- The pyrene-containing nanorings described in Chapter 2 are named pyrenophynes, which consist of ethylene bridges between each of the two aromatic units. These nanorings are analogs to Oda's para-phenylene-ethynylene derivatives. Several synthetic methods have been attempted. Although the final pyrenylene-ethylnylene nanorings have not been synthesized yet, the formation of a key intermediate tetrathiacyclophyne has been verified by experiment evidence and will be instructive to future research. -- In Chapter 3, the syntheses of pyrenophanes are made up of all aromatic units are described, including the pyrenophane with central para-phenylene, meta-phenylene, and 2,5-thienylene units. Müllen's methodology of building nanographitic sheets was adopted to construct the skeleton of these pyrenophanes. -- In Chapter 4, synthetic investigation focuses on extremely distorted aromatic systems. In order to achieve a more distorted (2,7)pyrenophane than all the previously synthesized ones in the Bodwell group, a series of octaphenyl pyrenophanes with a central aliphatic bridge were synthesized, and the most distorted (2,7)pyrenophane that has only 6 carbon atoms in the bridge was generated using the VID methodology.


identifier: Zhang, Chen <https://research.library.mun.ca/view/creator_az/Zhang=3AChen=3A=3A.html>   (2012) Estimation and forecasting of a lag 2 dynamic model for infectious diseases.  Masters thesis, Memorial University of Newfoundland.

abstract: When a common infectious disease is first detected in a community, it may quickly spread out through air, water, public facilities and personal contacts. At a given time point, each infected individual may or may not infect other individuals in the community. Meanwhile, it is also possible that some individuals who carry the same disease travel into the community. In the present work, we discuss estimation and forecasting of an extension to the lag 1 longitudinal dynamic model for correlated data used by Oyet & Sutradhar (2011) for modelling the spread of infectious disease. The lag 1 model only allow individuals with infection at time point t–1 to cause new infections at time point t. Clearly, if at time point t–2, there is an individual who is still infected by the disease, it is also possible for this individual to infect others at time point t. The present model discussed in this work allows for such a possibility. During the modelling, we consider stationary and nonstationary covariates. We also extend the model to situations where unobservable community effect and the latent community effect is present. The regression parameter β and the parameter of latent community effect δ 2/γ are estimated by generalized quasi-likelihood (GQL) approach. The correlation parameters ρ1 and ρ2 are estimated by using method of moments. In each of the cases, we examined the accuracy of the estimates and forecasts through simulation studies.


identifier: Zhang, Daiying <https://research.library.mun.ca/view/creator_az/Zhang=3ADaiying=3A=3A.html>   (2011) Femtosecond laser microfabrication for opto-microfluidic devices in glass.  Masters thesis, Memorial University of Newfoundland.

abstract: The femtosecond laser has been a powerful tool to achieve laser processing and microfabrication due to the advantages of unprecedented high peak intensity, a small heat-affected zone and the capability of three dimensional fabrication on micro-/nano-scales. -- In recent years, opto-microfluidics has emerged and progressed rapidly with many practical applications. Various microchannels and optical components have been integrated into a palm-size chip to accomplish optical measurements, clinical diagnostics, molecular analysis, and chemical synthesis. Opto-microfluidic devices significantly reduce reagent consumption, waste production, analysis time and labour costs. -- In this dissertation, femtosecond laser microfabrication for the opto-microfluidic devices in fused silica is studied. Femtosecond laser microfabrication on the surface and in the bulk of the samples is achieved using analysis on the influence of various fabrication parameters. Fabrication of surface / bulk microchannels of variable specifications has been demonstrated by femtosecond laser microfabrication assisted by hydrofluoric acid etching. The feasibility of fabricating of waveguides in glass with femtosecond lasers has also been proved. Laminar flow and particle counting are accomplished with the femtosecond laser microfabricated opto-microfluidic devices. The effectiveness of these prototype opto-microfluidic devices is investigated.


identifier: Zhang, Fang <https://research.library.mun.ca/view/creator_az/Zhang=3AFang=3A=3A.html>   (2006) Global dynamics of some spatially heterogeneous population models.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: The conjoining of nonlinear dynamics and biology has brought about significant advances in both areas, with biology promoting developments in the theory of dynamical systems and nonlinear dynamics providing a tool for understanding biological phenomena. Since the 1970's, various differential equations models have been proposed to study the evolutionary (long term) behavior of interacting species, the transmission of infectious diseases, biological invasions and disease spread. The purpose of this PhD thesis research project is to investigate the global dynamics and traveling waves in some spatially heterogeneous population models. -- In chapter 1, we present some elementary concepts and theorems based on the theories of uniform persistence and coexistence state, chain transitive sets, monotone dynamics, spreading speeds and traveling waves. -- In chapter 2, we study the global dynamics of a non-autonomous predator-prey system with dispersion. We establish sufficient conditions for uniform persistence and global extinction, the existence, uniqueness, and global stability of the positive periodic solutions. After that, we lift these results to asymptotically periodic systems. -- It has been observed that population dispersal affects the spread of many infectious diseases. An epidemic model in a patchy environment with periodic coefficients is investigated in chapter 3. Motivated by the works of Wang and Zhao [51], we present a disease transmission model with population dispersal among n patches, and we assumed that these coefficients are periodic with a common period due to the seasonal effects. We focus mainly on establishing a threshold between the extinction and the uniform persistence of the disease, and the conditions under which the positive periodic solution is globally asymptotically stable. -- In the book [41], L. Rass and J. Radcliffe raised an open problem on the spreading speed and traveling waves for an epidemic model on the integer lattice Z. We address this problem in chapter 4 by appealing to the theory of spreading speeds and traveling waves for monotone semiflows [34]. More precisely, we establish the existence of asymptotic speeds of spread, and show that this spreading speed coincides with the minimal wave speed for monotone traveling waves. -- Chapter 5 is devoted to the investigation of the asymptotic behavior for a reaction diffusion model with a quiescent stage, which was proposed by Hadeler and Lewis [18]. By appealing to the theory of spreading speeds and traveling waves for monotone semiflows, we establish the existence of asymptotic speed of spread and show that it coincides with the minimal wave speed for monotone traveling waves. By the theory of monotone dynamical systems and the persistence theory, we prove a threshold type result on the global stability of either the zero solution or a unique positive steady state in the case where the spatial domain is bounded.  -- To illustrate the obtained mathematical results, we also provide numerical simulations in chapters 2-5. -- At last, we summarize the results we have obtained in the thesis, and also point out some problems for future research in chapter 6.


identifier: Zhang, Hongbing <https://research.library.mun.ca/view/creator_az/Zhang=3AHongbing=3A=3A.html>   (1993) The analysis of organic constituents in leaves by pyrolysis-gas chromatography and its application to selected environmental effects on plants.  Masters thesis, Memorial University of Newfoundland.

abstract: Forest decline has caused great concern in North America. In recent years, the relationship between environmental stress and the concentration of certain organic compounds in plant leaves, e.g., carbohydrates, phenolics and tannins, has been recognized. Traditional methods for the determination of organic constituents in leaves are very difficult as well as time-consuming. As an alternative method of analysis, Pyrolysis-Gas Chromatography-Mass Spectrometry (PY-GC-MS) can be a rapid and comprehensive method to profile the chemical composition of biomaterials. Furthermore, enhanced structural information of biomolecules containing acidic functional groups has been obtained by a modification of direct pyrolysis - simultaneous pyrolysis methylation (SPM). Initial investigations were focused on the characterization of important classes of biomarkers (e.g., tannins, phenolics) in leaves, and, optimization of sample preparation procedures and pyrolysis conditions. Finally, the pyrolytic techniques were examined as a tool to quantify the compositional changes in leaves of trees which have been subjected to different environment stresses. Results will be reported for three field applications 1) the effect of thinning on balsam fir trees 2) the effect of fertilization on kalmia plant 3) and the effect of ozone on white pine trees. It was found that certain pyrolysates of carbohydrates, tannins and of a dihydrochalcone where good indicators of fertilization and water stress. Two unique pyrolysate bio-markers were discovered in white pine needles as indicators of ozone fumigation levels and ozone damage.


identifier: Zhang, Jianjun, 1967 July 31- <https://research.library.mun.ca/view/creator_az/Zhang=3AJianjun,_1967_July_31-=3A=3A.html>   (2003) An algorithm for the extraction of ocean wave information from bistatic HF groundwave radar data: a simulation.  Masters thesis, Memorial University of Newfoundland.

abstract: In this thesis an algorithm is developed for the inverse problem of bistatic scattering from the ocean surface. Narrow beam bistatic high frequency (HF) radar data from the ocean surface are simulated and the non-directional ocean wave spectrum is recovered. The water depth is set to be arbitrary. Zero-mean Gaussian noise from external sources is taken into account. -- The bistatic HF radar cross sections are applied to the general-depth water case. The second-order cross section of patch scattering is a two-dimensional Fredholm-type integral equation of first kind. It contains a non-linear product of ocean wave directional spectrum factors in its integrand. The energy inside the first-order cross section is derived to normalize this integrand. The unknown ocean wave spectrum is represented by truncated Fourier series. The integral equation is then converted to a matrix equation and a singular value decomposition (SVD) method is invoked to pseudo-invert the kernel matrix. The non-directional ocean wave spectrum is obtained from the Fourier coefficient α₀. -- The zero-mean Gaussian noise from external sources is added to simulate pulsed HF radar clutter from the ocean surface. The power spectral densities of the clutter and noise are obtained by means of a periodogram. The combination of power spectral densities of clutter and noise makes the simulated bistatic radar data correspond more closely with actual observations. The inverse algorithm is carried out with respect to radar data for varying water depths, wind velocities, and radar operating frequencies. The results are compared with the original ocean wave spectrum.


identifier: Zhang, Kai <https://research.library.mun.ca/view/creator_az/Zhang=3AKai=3A=3A.html>   (2001) Thermodynamics of aqueous 2-amino-2-methyl-1-propanol and 2-amino-2-methyl-1-propanol hydrochloride over a wide range of temperature and pressure: apparent molar volumes, heat capacities, excess molar heat capacities, volumes, and expansibilities.  Masters thesis, Memorial University of Newfoundland.

abstract: Please see thesis for abstract.


identifier: Zhang, Lei <https://research.library.mun.ca/view/creator_az/Zhang=3ALei=3A=3A.html>   (2004) Cholinrergic excitation of dopamine neurons in the ventral tegmental area.  Masters thesis, Memorial University of Newfoundland.

abstract: Ventral tegmental area dopaminergic neurons are critically involved in brain mechanisms of reward, motivation, and emotional arousal. The natural cholinergic agonist nicotine is highly addictive and believed to cause addiction through activating the central dopamine system. In this thesis, we used perforated patch-clamp recording to examine the effects of the cholinergic agonist carbachol on the excitability of dopamine neurons in brain slices. Results from these experiments revealed that bath application of carbachol (20 μM) for 1-2 min excited most cells in the VTA regardless of their membrane characteristics and neurochemical identities. Muscarinic and nicotinic receptors appeared to contribute equally to carbachol-induced excitation. A majority of cells putatively identified as dopaminergic based on the expression of hyperpolarization-activated current and dopamine-induced autoinhibition, responded to carbachol with depolarization and an increased rate of firing. Of these cells, 13% responded to the carbachol with a switching of firing pattern from tonic firing to bursting. Carbachol-induced excitation and bursting were all reversible and could be prevented by combined muscarinic and nicotinic antagonism. -- The synaptic blocker cocktail containing 100 μM APV (NMDA receptor blocker), 10 μM CNQX (AMPA receptor blocker) and 100 μM picotoxin (GABAA receptor blocker) did not alter carbachol's effect on neuronal excitability and bursting. In addition, a small proportion of dopamine cells were spontaneously bursting in the slice. The characteristics of these bursts were very similar to those induced by carbachol. Both spontaneous and carbachol-induced bursting could be blocked by the non-selective Ca²⁺ channel blocker cadmium and the L-type Ca²⁺ channel blocker nifedipine, while blocking the T-type Ca²⁺ channels did not have any effect on bursting. Spontaneous and induced bursting occurred on a slow, large amplitude membrane oscillation or hump potential which was dependent on Ca²⁺ entry through voltage-gated Ca²⁺ channels, and more specifically through the L-type Ca²⁺ channels. -- In summary, the present investigation provides evidence that cholinergic excitation of dopamine cells is mainly postsynaptic. More importantly, cholinergic activation can serve as a trigger that switches the firing mode of dopamine cells and promotes burst firing. Burst firing induced as such is dependent on Ca²⁺ entry through the L-type Ca²⁺ channels, suggesting a new target for modulating the central dopamine system.


identifier: Zhang, Ning <https://research.library.mun.ca/view/creator_az/Zhang=3ANing=3A=3A.html>   (2013) Capacitary estimates for Hessian operators.  Masters thesis, Memorial University of Newfoundland.

abstract: Please see thesis for abstract.


identifier: Zhang, Wei <https://research.library.mun.ca/view/creator_az/Zhang=3AWei=3A=3A.html>   (2010) Development of new techniques for impregnated diamond coring bit wear measurement in conventional rotary drilling and vibration assisted rotary drilling.  Masters thesis, Memorial University of Newfoundland.


identifier: Zhang, Yi <https://research.library.mun.ca/view/creator_az/Zhang=3AYi=3A=3A.html>   (2012) Traveling wavefronts of non-local reaction-diffusion models for cell adhesion and cancer invasion.  Masters thesis, Memorial University of Newfoundland.

abstract: Cell adhesion is a fundamental mechanism binding a cell to a surface, extracellular matrix or another cell through cell adhesion molecules. This cell behavior is involved in various biological processes including embryogenesis, migration and invasion, tissue remodeling and wound healing. This paper investigates the existence of traveling wavefronts of a non-local reaction-diffusion model for cell behavior proposed first by Armstrong et al. (J. Theor. Biol. , 243 (2006), 98-113), and by Sherratt et al. (European J. Appl. Math., 20 (2009), 123-144). We provide a valid approach by using perturbation methods and the Banach fixed point theorem to show the existence of wavefronts for the model with some suitable parameter values. Numerically, the solutions with initial step functions eventually stabilize to a smooth wavefront for a relatively small adhesion coefficient. We also consider the application of this model to study the cancer invasion process, which results in a. system with solutions reflecting the relation between cell-cell and cell-matrix adhesion in t he cancer invasion regulation. Using the same method employed in the cell-adhesion model, the existence of traveling wavefronts to this system is established. Finally numerical simulations are presented to verify the effectiveness of our proposed theoretical results and to demonstrate some new phenomena that deserve further study in the future.


identifier: Zhang, Ying <https://research.library.mun.ca/view/creator_az/Zhang=3AYing=3A=3A.html>   (2011) An analysis of international students' self-identified competencies gained through a co-curricular career development program.  Masters thesis, Memorial University of Newfoundland.

abstract: International students form a potential pool of highly skilled immigrants in Canada. Literature shows that during their transition to employment international students encounter different barriers, including language barriers, cultural difficulties, policy barriers, and so on. Limited academic research had been conducted regarding how career development programs in post-secondary institutions help international students with transition to employment. -- This study aimed to investigate how the Professional Skills Development Program (PSDP) at Memorial University helped international students with transition to employment. A case study approach with mixed methods was employed. The findings of this study confirmed the importance of providing job search techniques to international students. The major findings also revealed how networking and service learning playa significant role in helping international students gain essential career competencies to enhance their transition to employment. Understanding what competencies international students self-identified through their participation in the PSDP will facilitate future career development programs in providing better services for international students.


identifier: Zhang, Yuxiang <https://research.library.mun.ca/view/creator_az/Zhang=3AYuxiang=3A=3A.html>   (2012) Global dynamics of some population models with spatial dispersal.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: Spatial evolution is a very important phenomenon in ecology and epidemiology. In mathematics, integro-difference/differential equations or reaction-diffusion equations are often used to describe different spatial spread/invasion phenomena. In this thesis, we investigate the global dynamic of some integro-difference and reaction-diffusion population models with spatial dispersal and temporal heterogeneities. -- In Chapter 1, we present some basic terminologies and theorems which are used in this thesis. They are involved in monotone dynamics, spreading speeds and traveling waves, basic reproduction ratio, and chain transitive sets. -- Chapter 2 is devoted to investigate the spatial dynamics for a class of discrete-time recursion systems, which describe the spatial propagation of two competitive invaders. The existence and global stability of bistable traveling waves are established for such systems under appropriate conditions. -- In Chapter 3, we study spreading speeds and traveling waves for a class of reaction-diffusion equations with distributed delay. Such an equation describes growth and diffusion in a population where the individuals enter a quiescent phase exponentially and stay quiescent for some arbitrary time that is given by a probability density function. The existence of the spreading speed and its coincidence with the minimum wave speed of monostable traveling waves are established via the finite-delay approximation approach. We also prove the existence of bistable traveling waves in the case where the associated reaction system admits a bistable structure. Moreover, the global stability and uniqueness of the bistable waves are obtained in the case where the density function has zero tail. -- In Chapter 4, we investigate a periodic reaction-diffusion competition model, which describes the propagation of two competitive species in bad and good seasons. The existence and global stability of time-periodic bistable traveling waves are established for such a system under appropriate conditions. -- In order to study the evolution dynamics of the Lyme disease in a periodic environment, in Chapter 5, we propose a reaction-diffusion Lyme disease model with seasonality. In the case of a bounded habitat, we obtain a threshold result on the global stability of either disease-free or endemic periodic solution. In the case of an unbounded habitat, we establish the existence of the disease spreading speed and its coincidence with the minimal wave speed for time-periodic traveling wave solutions. We also estimate parameter values based on some published data, and use them to study the Lyme disease transmission in Port Dove, Ontario. -- In Chapter 6, we present a brief summary of this thesis and some future works.


identifier: Zhao, Guming <https://research.library.mun.ca/view/creator_az/Zhao=3AGuming=3A=3A.html>   (2003) Thinking and teaching for a narrative perspective.  Masters thesis, Memorial University of Newfoundland.

abstract: This thesis has no abstract.


identifier: Zhao, Jian Ping <https://research.library.mun.ca/view/creator_az/Zhao=3AJian_Ping=3A=3A.html>   (1996) Excess molar enthalpies of carbon dioxide with polar solvents in the vicinity of the critical point.  Masters thesis, Memorial University of Newfoundland.

abstract: Please see thesis for abstract.


identifier: Zhao, Wei <https://research.library.mun.ca/view/creator_az/Zhao=3AWei=3A=3A.html>   (2003) A moving boundary approach for cylinders subjected to high internal pressure.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: This dissertation proposes a novel analytical approach for elastic plastic analysis of thick wall cylinders under internal pressure. It involves two parametric functions and piecewise linearization of the stress strain curve. A deformation type of relationship is combined with Hooke's law in such a way that stress strain law has the same form in all linear segments of the material curve, but each segment involves different material parameters. -- This approach incorporates the deformed geometry in elastic plastic analysis of thick wall cylinders. Using an iterative procedure based on the principle of virtual work, this approach accounts for the effect of deformed geometry due to high internal pressure. The resulting analytical formulation is capable of predicting stress, strain, displacement, and energy on a moving boundary basis. -- The analytical formulation for autofrettaged cylinders obeying work hardening material behavior has also been presented. An iterative implementation procedure for shakedown pressure calculation has been developed. Shakedown pressures have been calculated for both undeformed geometry and deformed geometry. The proposed formulation has also been applied to plastic collapse load estimation. Calculations indicate that the moving boundary approach provides conservative plastic collapse load estimation compared with the traditional small deformation theory. -- This moving boundary approach is appropriate for inelastic analysis including autofrettage, shakedown, and limit analysis on thick wall cylinders. The comparison of the analytical formulation with the ANSYS inelastic finite element analysis is favorable. -- The effect of deformed geometry on inelastic analysis has been assessed on thick wall cylinders subject to high internal pressure. The discrepancy of results between the proposed method and small deformation theory has been analyzed. Calculation indicates that the difference of energy is significant for high internal pressures. -- The J integral of thick wall cylinders with circumferential flaw has been evaluated using the ANSYS finite element program. The result indicates a significant difference between the analysis using large deformation and small deformation theories. This difference depends on the magnitudes of the internal pressure, and is dependent on the material behavior. It indicates that neglecting the difference can be unconservative when evaluating the inelastic fracture parameter, J integral. Therefore the proposed approach is appropriate for representing energy of deformation in the energy approach in fracture mechanics, as it incorporates the effect of geometric change due to high internal pressures. -- As the analytical approach can be implemented by MAPLE program, this method represents an alternative assessment tool that can be used for inelastic analysis of thick wall cylinders, which is usually performed by the more expensive and elaborate nonlinear finite element analysis.


identifier: Zheng, Nan <https://research.library.mun.ca/view/creator_az/Zheng=3ANan=3A=3A.html>   (2005) Analysis of binary phospholipid bilayers with a self-consistent field theory.  Masters thesis, Memorial University of Newfoundland.

abstract: This thesis applies a self-consistent field theory of compressible, fully hydrated phospholipid binary mixtures to an idealized model of binary bilayers. The theory is extended to calculate the average order parameter and gauche isomer number on each layer, as well as distributions of the chain-segments. It then makes calculations for a series of mixtures to present systematically the effects of composition and chain length mismatch on the structural properties, and to make comparison with experiments. In the theory, the effective fields, and the inhomogeneous particle and bond distributions throughout the bilayer interior are related self-consistently. This allows numerical calculation of all these properties. -- Experimental results for binary mixtures such as distearoylphosphatidylcholine (DSPC)/dimyristoylphosphatidylcholine (DMPC) and galactosylceramide (GalCer)/1-stearoyl-2-oleoyl phosphatidylcholine (SOPC) show the influence of chain length mismatch and composition on each component, in particular a feature called the "second plateau" in the order parameter profile near the tail of the long chain. To interpret and compare with these systems and phenomena are the foci of this work.


identifier: Zheng, Nan <https://research.library.mun.ca/view/creator_az/Zheng=3ANan=3A=3A.html>   (2013) Inference in stochastic volatility models for Gaussian and t data.  Masters thesis, Memorial University of Newfoundland.

abstract: Two competing analytical approaches, namely, the generalized method of moments (GMM) and quasi-maximum likelihood (QML) are widely used in statistics and econometrics literature for inferences in stochastic volatility models (SVMs). Alternative numerical approaches such as Markov chain Monte Carlo (MCMC), simulated maximum likelihood (SML) and Bayesian approaches are also available. All these later approaches are, however, based on simulations. Tagore (2010) revisited the analytical estimation approaches and proposed simpler and more efficient method of moments (MM) and approximate GQL (AGQL) inferences for the estimation of the volatility parameters. However, Tagore (2010) did not consider the estimation of the intercept parameter (γ0) in the SV model, and also the model was confined to the normal based errors only. -- In this thesis, we first extend Tagore's MM and AGQL approaches (Tagore 2010) to the estimation of all parameters of the SV model including the so-called intercept parameter γ0. Second, we modify the existing QML approach and unlike Tagore (2010) include this approach in the simulation study. Furthermore, all three approaches are applied to analyze a real life dataset. -- Next, we consider a t-distribution based SV model, and apply the aforementioned estimation approaches for all parameters including a new degrees of freedom parameter of the t-distribution. Simulation studies are conducted to examine the relative performances of the estimation approaches. We also compute the kurtosis of the t-distribution based SV models and make an exact comparison with those of normal distribution based SV models. The estimation effect of parameters on the kurtosis is given for a special case.


identifier: Zhong, Ning <https://research.library.mun.ca/view/creator_az/Zhong=3ANing=3A=3A.html>   (2004) Color segmentation based on adjustable fuzzy neural networks and high level understanding of maps.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: To digitize and record electronically the huge collection of topographical maps, development of a framework for computer-based color segmentation and high-level map understanding has shown an increasing importance. -- Color map segmentation requires special treatment with respect to line features. However, few research efforts have been put into this area. A novel approach of color segmentation based on adjustable fuzzy neural networks is proposed. The approach is capable of capturing pixel variations along thin line features. Based on a physics model, two heuristics have been derived, which suggest certain pixel variation behaviors in overlapping and boundary areas respectively. Fuzzy neural networks combined with self-adjustment components have been developed. The self-adjustment components dynamically adjust sample pixels among different sample clusters in neural network training. A feature that distinguishes this method from previous supervised neural computing methods is that, by adoption of self-adjustment architectures, it does not strictly require that all samples should have their desired outputs given in advance. Experiments show that the developed method can produce satisfactory segmentation results. -- This study also proposes a novel method for high-level map understanding. A Description Logics (DL) language, GALL(l,D), is introduced to represent spatial objects and their relationships. A set of derivation rules is then proposed to derive a special grammar, called map grammar, from the DL representation. Thus, the map understanding process can be treated as a grammar parsing process. The map grammar is different from traditional grammars in that: (1) it allows for ambiguity; and (2) the input is a collection of primitive map objects instead of an ordered sequence of tokens. A map grammar parsing algorithm based on the Multiple Path Stack (MPS) is proposed. One advantage of this approach is that the knowledge representation is verifiable at design time. In addition, the implementation based on this approach is more robust and highly reusable, since the knowledge representation is separated from the inference mechanism. This research is a first step towards applying DL theory to map understanding. A prototype map understanding system was developed and applied on several test maps. The results show that this method can obtain a satisfactory interpretation of map phenomena.


identifier: Zhong, Ying <https://research.library.mun.ca/view/creator_az/Zhong=3AYing=3A=3A.html>   (2010) Preparation of epigallocatechin gallate esters and evaluation of their antioxidant, antiviral, anti-inflammatory and anticancer effects.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: Epigallocatechin gallate (EGCG), a major green tea polyphenol, has been widely studied and proposed as a functional food ingredient and nutraceutical for therapeutic use. However, EGCG is highly hydrophilic with poor solubility in lipophilic media which hinders its widespread application in foods and affects its absorption in vivo, resulting in limited uptake by the cells and bioavailability when ingested orally. Therefore, it is important to alter the hydrophilicity/lipophilicity balance (HLB) of EGCG in order to take better advantage of its multifunctional properties. This work investigated structural modification of EGCG, more specifically esterification with fatty acids of different chain length and degree of unsaturation, as an approach to improving the lipophilicity while maintaining the maximum efficacy or even introducing novel bioactivities not found in the original EGCG. Additional perspectives may exist using the health beneficial omega-3 polyunsaturated fatty acids (PUFA) as acyl donors. For this purpose, lipophilic ester derivatives of EGCG with butyric, stearic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids were prepared, and their bioactivities evaluated, including antioxidant activities in different model systems, anti-inflammatory, antiviral and anticancer activities. The results indicated that lipophilization by esterification, especially with omega-3 PUFA, significantly improved the antioxidant and anti-inflammatory activity of EGCG. Moreover, the ester derivatives totally arrested colon cancer in mice, and exhibited an anti-HCV (hepatitis C virus) activity 1700-folds greater than that of the positive control embelin. These findings strongly suggest that the EGCG ester derivatives are of great potential as lipophilic alternatives of the water-soluble EGCG and may serve as novel functional ingredients for food, cosmetics, and nutraceutical/therapeutical applications and for use in medicine and natural health products.


identifier: Zhou, Ningzhang <https://research.library.mun.ca/view/creator_az/Zhou=3ANingzhang=3A=3A.html>   (2004) Further progress towards enantioselective total synthesis of the bisbenzyltetrahydroisoquinoline alkaloid (-)-cycleanine.  Masters thesis, Memorial University of Newfoundland.

abstract: Bisbenzylisoquinoline (BBIQ) alkaloids are a large group of compounds which outnumber those of most of the other alkaloid families. These compounds occur in many different plants and usually display a variety of pharmacological properties such as antitumor and antibacterial activities. The two benzylisoquinoline subunits in BBIQs can be connected through an oxygen atom or by carbon-carbon linkage. The subunits may have the same or opposite configurations at their asymmetric centres. BBIQs may also contain dihydroisoquinoline or tetrahydroisoquinoline units. A vast number of possible structures may be constructed in this way which make BBIQs very interesting synthetic targets. -- In this thesis, the asymmetric synthesis of the BBIQ (-)-cycleanine was attempted. A chiral auxiliary-assisted diastereoselective Bischler-Napieralski cyclization was used to form the two correct tetrahydroisoquinoline subunits. Two different methods of recently reported improved Ullmann coupling methods, namely (a) N,N-dimethylglycine promoted coupling, and (b) 2,2,6,6-tetramethylheptane-3,5-dione-accelerated coupling were first employed to build the framework of the target molecule. The use of a methodology of using a mild SNAr reaction between phenols and electron-deficient aryl fluorides was also evaluated. In addition, some efforts at making some intermediates for the total synthesis more synthetically accessible are also discussed.


identifier: Zhou, Yang <https://research.library.mun.ca/view/creator_az/Zhou=3AYang=3A=3A.html>   (2003) Relationship between α-amylase degradation and the structure and physicochemical properties of legume starches.  Masters thesis, Memorial University of Newfoundland.

abstract: Starches from different cultivars of black beans, pinto beans, smooth peas, lentils and wrinkled peas were isolated and their composition, physicochemical properties and susceptibility towards porcine pancreatic a-amylase were determined. -- The yield of starch ranged from 16.4 to 34.1% on a whole seed basis. The shape of the granules in black bean, pinto bean, smooth pea and lentil varied from round to oval to irregular, while compounds in rounded rosette were observed for wrinkled pea starch. Bound and total lipids ranged from 0.26 to 0.80% and 0.35 to 0.84%, respectively. The total amylose content of black bean, pinto bean, smooth pea and lentil were in the range of 30.5-39.3%, whereas that of wrinkled pea was much higher (78.4%). The percentage of lipid-complexed amylose in native starches ranged from 10.3 to 12.2%. The X-ray diffraction pattern was of the 'B' type in wrinkled pea starch and of the 'C' type in the other starches. The relative crystallinity and the 'B' polymorphic content ranged from 17.7 to 33.4% and 27.1 to 92.2%, respectively. Wrinkled pea starch exhibited the lowest relative crystallinity (17.7%) and the highest 'B' polymorphic content (92.2%). -- The swelling factor (SF) and the extent of amylose leaching (AML) of native starches were in the range of 3.4-17.7 and 11.0-17.8%, respectively. The gelatinization temperatures (To , Tp, Tc) and enthalpy (ΔH) of native starches (with the exception of wrinkled pea starch) were in the range of 60.0-65.7°C, 66.0-76.5°C, 76.4-88.8°C, and 14.6-20.1mJ/mg, respectively. Differences in SF, AML, To , Tp, Tc, and ΔH between cultivars of the same species were more pronounced in black bean and lentil starches. Wrinkled pea starch did not show an endothermic peak indicating that starch chain interactions within the amorphous domains were more extensive in wrinkled pea starch. -- All starches exhibited a biphasic hydrolysis pattern, i.e. a relatively rapid rate initially followed by a progressively decreasing rate thereafter. Wrinkled pea starch exhibited a much higher initial hydrolysis velocity than did the other starches. Cultivars of black bean and lentil showed significant differences in their initial velocities. However, differences in initial velocity between cultivars of smooth pea and pinto bean were not significant. Black bean, lentil and wrinkled pea starches showed a plateau at 93, 85 and 65% hydrolysis, respectively. The time taken for the appearance of the plateau was identical for the black bean cultivars, but was different for the lentil cultivars. Pinto bean and smooth pea cultivars showed no plateau. At the end of the assay period (120h), cultivars of each legume species were hydrolyzed to the same extent, and the extent of hydrolysis among the legume species followed the order: black bean > lentil > smooth pea > pinto bean > wrinkled pea. Scanning electron micrographs showed that starches were slightly eroded during the initial hydrolysis stage (<20% hydrolysis), but the integrity of most of the granules was well maintained. However, roughened surfaces and disc like depressions were obvious for all starches, except for lentil starch. No morphological differences were observed between cultivars from the same species for both native and hydrolyzed starches. The X-ray diffraction pattern and the 'B' polymorphic content of all starches remained unchanged upon hydrolysis. However, the relative crystallinity increased in wrinkled pea, but remained unchanged in the other starches. On hydrolysis, the apparent amylose content decreased in all starches. The extent of this decrease was most pronounced in wrinkled pea. In all starches, the enthalpy of gelatinization decreased, and the gelatinization transition temperatures increased slightly, on hydrolysis. -- This study demonstrated that differences in the composition and physicochemical properties of starch between cultivars from the same species were marginal. The rate and extent of hydrolysis were influenced mainly by structural organization and interactions of the starch chains within the native granule, as well as by the extent of association between hydrolyzed amylose chains.


identifier: Zhu, Jun <https://research.library.mun.ca/view/creator_az/Zhu=3AJun=3A=3A.html>   (2004) Development of polypyrrole/nafion composite membranes and a dynamic hydrogen reference electrode for direct methanol fuel cells.  Masters thesis, Memorial University of Newfoundland.

abstract: One major goal of this research was to increase the fuel efficiency and cell performance of direct methanol fuel cells (DMFCs) by decreasing the methanol crossover from the anode to the cathode. Polypyrrole/Nafion composite membranes were prepared, and factors influencing the modification procedures were studied. An optimized, reproducible modification procedure was developed. The composite membranes outperformed pure Nation 115 but need a longer activation time. The polarization and electrochemical impedance spectroscopy measurements showed that the activation process was due to two main factors: slow membrane hydration and slow cathode activation. The composite membranes showed an over 40% reduction in methanol crossover and a 70% increase in membrane resistance relative to Nafion 115. To further decrease the membrane resistance, counter ions were provided in the modification process. Poly[3-(pyrrole-l-yl)propanesulfonate ]/Nafion composite membranes were also prepared to address this problem. -- Another major goal was to develop and characterize a micro reference electrode to resolve the anode and cathode behavior in a fuel cell. An edge type Pt wire Dynamic Hydrogen Electrode (DHE) reference electrode was developed and used in a hydrogen proton exchange membrane fuel cell and a DMFC. The advantage of this DHE is that it is easy to use and does not require modification of the fuel cell hardware. This reference electrode provided good qualitative information. However, potential drift over long times makes it inappropriate for long-term measurements.


identifier: Zhu, Lin <https://research.library.mun.ca/view/creator_az/Zhu=3ALin=3A=3A.html>   (2006) Model riser test for vortex induced vibration in a sheared current.  Masters thesis, Memorial University of Newfoundland.

abstract: This thesis describes a laboratory investigation and a method for analysis of multi-mode vortex induced vibration of a flexible slender riser model which was subjected to a sheared current and a uniform current. The Reynolds number of the tests was in the region from 2127 to 40,171 which belonged to the subcritical range. -- The model riser was made of an 8.5 m long and 0.047 m diameter rubber hose. Twenty pairs of accelerometers were spaced inside the rubber hose to monitor the in-line and crossflow vortex induced vibration responses which will be abbreviated as VIV responses later. The simplified shear flow was produced by a 4 m or 3.5 m long and 38 cm diameter PVC pipe. The model riser segment covered by the PVC pipe stayed in still water and the other part was subjected to a uniform velocity. -- A total of 120 test runs were conducted in the VIV experiment. The test flow velocity range was from 0.1 to 1.0 m/s and increments were 0.1 m/s. The duration of each run was two minutes. Most tests were done twice for the same velocity profile and same pretension in respectively up run test and down run test. The so-called up run test denotes that test current velocities change from low to high. In contrast, the down run test represents that test current velocities change from high to low. In addition, a thirty minute data acquisition sustained test was performed in a sheared current. -- The test analysis was conducted in the time-domain, the frequency-domain and the space-domain. Close attention was paid to investigation of the multi-mode responses, the lock in phenomenon, the difference between the up run test and down run test, and sudden changes occurring in the thirty minute data acquisition sustained test. -- In the thesis, a comparison method is used to help understand the behavior of the VIV responses. The riser VIV test results in uniform currents had been completed before. These test results were familiar to us. Through comparing the test results in the sheared currents with the uniform currents, the test results in sheared currents can be understood better. A rough comparison of the two uniform tests in the Ice Tank and in the Flume Tank is done. Here it was found that reduced velocity V* corresponding to the model VIV maximum amplitude does not change in between these two tests.


identifier: Zimmermann, Emily W. <https://research.library.mun.ca/view/creator_az/Zimmermann=3AEmily_W=2E=3A=3A.html>   (2012) Escape-related behaviour of Atlantic cod (Gadus morhua): motivation to escape from sea cages and spatiotemporal dispersal post-escape.  Masters thesis, Memorial University of Newfoundland.

abstract: This study addresses the potential for interaction between escapee farmed and wild cod following escape from aquaculture sea cages. The first chapter introduces the topic of fish escapes from a behavioural perspective. The second chapter investigates the role of suboptimal conditions and individual temperament on net biting behaviour. The data suggest that appropriate feeding levels combined with cage enrichment, as well as good net maintenance, may lead to reduced net interactions and thus fewer holes, reducing the potential for fish to escape. In the third chapter, I used acoustic telemetry to determine the spatiotemporal distribution of local wild cod and escapee farmed cod following a simulated escape. Farmed cod dispersed from the cage site rapidly and mixed with local wild cod, suggesting a high potential for interactions and highlighting the importance of reducing escapes before they occur. These results can be applied to reduce the number of escapes, streamlining the development of the industry before mitigation becomes too difficult and costly to implement.


identifier: Zou, Yubo <https://research.library.mun.ca/view/creator_az/Zou=3AYubo=3A=3A.html>   (2006) Decycling and dominating cubes and grids.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: Please see thesis for abstract.


identifier: Zubayer, Hossan Mohammad <https://research.library.mun.ca/view/creator_az/Zubayer=3AHossan_Mohammad=3A=3A.html>   (2011) Design analysis of line-start interior permanent magnet synchronous motor.  Masters thesis, Memorial University of Newfoundland.

abstract: The past 25 years have been a significant period with advances in the development of interior permanent magnet machines. Over this period, line-start interior permanent magnet synchronous motors have expanded their presence in the industrial and domestic marketplace from few specialized niche markets in high efficiency machine tools, household appliances, small utility motors and servo drives to mass-produced automotive applications. A closer examination reveals that several different knowledge-based technological advancements and market forces as well as consumer demand for high efficiency requirements have combined, sometimes in fortuitous ways, to accelerate the development of the improved new small energy efficient motors. -- Compared with squirrel-cage induction machines, line-start permanent magnet machines have high efficiency and high power factor because they exhibit two torque components namely the permanent magnet torque and the reluctance torque. Though the stator of a permanent magnet motor is the same as that of an induction motor, numerous configurations are possible in term of the ways the permanent magnet is placed in the rotor. In order to find the optimized structure, line-start permanent magnet synchronous machines with different rotor structures will be comparatively studied in terms of dynamics and steady state performance and transient process with finite element method. -- The advances in computing power have seen numerical methods like Finite Element Analysis (FEA) being employed n various design problems of interior permanent magnet (IPM) motors. This thesis presents the design, analysis and simulation of line-start IPM synchronous motors. Analytical derivations are provided. Taking into account inherent advantages of numerical methods like FEA for optimum design, shape and orientation of IPM motors, simulation codes for laboratory IPM motors are presented. Three sets of rotors for the IPMSM are analyzed using time-stepping FEA. This works provide cost effective simulations. The simulated results are compared with those published in the literature for verifications.


identifier: Zulaika, Joseba <https://research.library.mun.ca/view/creator_az/Zulaika=3AJoseba=3A=3A.html>   (1977) Fishing as a cultural system.  Masters thesis, Memorial University of Newfoundland.

title: Fishing as a cultural system

abstract: The ethnography for this thesis was carried out among Spanish deep-sea trawlermen fishing in the Northwest Atlantic ("Terranova"). After an introductory chapter, in which the spatial and social structures on board are outlined, as well as the juridical status and the specific technical performance of a Pareja ("Pair" of cod-trawlers dragging conjointly), the main body of the thesis aims to examine the features that culturally define the occupation of fishing. Emphasis is given to the proposition that fishermen create their own cultural context in response to their ecological and institutional experience. -- Although economic motivations are the raison d'etre of the "Terranova" fishing, the relations that the seamen evolve from within the marine environment, and the translation of the economic motivations to the levels of cognition and emotion, are direct subjects of this cultural analysis. The unpredictable fishing fluctuations are mentally organized around the key concept of luck, that becomes the condition of possibility for economic and emotional gratification. The conceptual order emerging from the indeterminacy of luck is systematically described. The view is taken that power on board participates in the system of signification involving luck. -- Likewise, the organization of social reality on board in the forms of time schedules, working conditions, safety guarantees, and so on, can only be understood in the light of a peculiar sense of order that the arbitrary causation of luck originates. -- Fishermen's emotional life is structured on the triangle represented by ship, foreign port, and home. The projective nature of ~he relations with family is stressed, in contrast with the severe limits of the actual family relations on shore. The foreign port offers the opportunity for a sexual double standard, which is revealing of the nature of the institutional life on board. The peculiar ethos of "being a fisherman" is described in the context of the relations developed from the ecological and cultural reality. -- Finally, the seamen's saying that "Terranova is a very round wheel" is intended as a metaphor, its signifying unity bringing together the environmental, social, cognitive, and emotional relations of fishing, as well as serving to recall the recent Canadian declaration of the 200-mile limit that implies for the near future a sudden end to all Spanish fishing in Terranova.


identifier: Abu-Kharma, Mahmoud <https://research.library.mun.ca/view/creator_az/Abu-Kharma=3AMahmoud=3A=3A.html>   (2005) Collision-induced absorption of the first overtone bands of H₂ and D₂.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: Enhancement spectra of the collision-induced absorption (CIA) of H₂ in its first overtone region 7500- 9500 cm⁻¹ in binary mixtures H₂ - N₂ and H₂ - CO were studied at 298 K for base densities of H₂ in the range 89 - 145 amagat and for partial densities of N₂ and CO in the range 19 - 392 amagat. The observed spectra consist of the quadrupolar double transitions: Q₂(J) (H₂) + S₀(J), O₀(J) and Q₀(J) (N2/CO), O₂(J) (H₂) + Q₀(J) (N₂/CO) and S₂(J) (H₂) + Q₀(J) (N₂/CO) with J = 0 to 4 for H₂ and J = 1 to 25 for N₂/CO. Enhancement absorption profiles of H₂-N₂ and H₂-CO were modelled by a total of 434 components of quadrupolar double transitions. The observed spectra agree with theoretical spectra and confirm that the isotropic overlap induction is absent in the 2 - 0 band of H₂ unlike in the CIA spectra of the fundamental band of H₂. The present analysis also confirms that there is no contribution from the electric dipole of CO to the induction mechanism in H₂ - CO mixtures. -- CIA spectra in the first overtone region from 5250 to 7250 cm⁻¹ of pure D₂ were studied at 77, 201 and 298 K. The observed spectra were modelled by a total of 92, 214 and 267 components of double vibrational transitions respectively. Enhancement spectra of the CIA in the first overtone region 5000 to 7000 cm⁻¹ of D₂ in D₂ - N₂ were studied at 298 K for a base density of D₂ of 73 amagat and for partial densities of N₂ in the range 150 - 370 amagat. The observed spectra were modelled with a total of 1176 components of double vibrational transitions. Enhancement spectra of the CIA in the first overtone region 5500 to 6750 cm⁻¹ of D₂ in the D₂-Ar, D₂-Kr and D₂-Xe binary mixtures were studied at room temperature for base densities of D₂ in the range 55 to 251 amagat and for partial densities of Ar, Kr and Xe in the range 46 to 384 amagat. The observed spectra consist of the following quadrupolar transitions: O₂(3), O₂(2), Q₂(J), J = 1 to 5 and S₂ (J), J = 0 to 5 of D₂. -- The observed spectra confirm that the isotropic overlap interaction does not contribute to the absorption of the first overtone band, unlike in the CIA spectra of the fundamental band. The binary and ternary absorption coefficients were determined from the integrated absorption coefficients of the band. Profile analysis of the observed spectra was carried out using the Birnbaum-Cohen line shape function for each component of the band and the characteristic half-width parameters δ₁ and δ₂ for the transitions were determined.


identifier: Abukharmh, Reem <https://research.library.mun.ca/view/creator_az/Abukharmh=3AReem=3A=3A.html>   (2007) The implementation of a probabilistic risk based inspection approach.  Masters thesis, Memorial University of Newfoundland.

abstract: Equipment and units in the hydrocarbon and chemical process industry are subject to several deterioration mechanisms that could lead to a loss of containment. This work presents an enhancement of a risk based inspection methodology earlier presented by Kallen (2002). This risk based inspection methodology uses a stochastic gamma function to model the materials deterioration rate. Using the prior knowledge of the deterioration rate and a Bayesian updating method, a posterior material deterioration model is found for two cases: perfect and imperfect inspections. Then, this material deterioration model is used to estimate the optimal inspection, replacement and failure times. -- Estimating inspection times depends on the material deterioration rate, age of the equipment, original material thickness, and the number of previous inspections that were carried on. The optimal inspection time aims to reduce the risk of failure due to deterioration mechanisms by maintaining the value of the equipment's damage factor as low as possible.


identifier: Abuzaytoun, Reem <https://research.library.mun.ca/view/creator_az/Abuzaytoun=3AReem=3A=3A.html>   (2005) The effect of bioactive constituents on plant oil stability.  Masters thesis, Memorial University of Newfoundland.

abstract: Algal oils and oils rich in alpha-linolenic acid (ALA), and gamma-linolenic acid (GLA) have been used for the treatment of a wide range of nutritional and clinical disorders. The algal oils of interest were arachidonic acid single cell oil (ARASCO), docosahexaenoic acid single cell oil (DRASCO), and a single cell oil rich in docosahexaenoic acid (DHA) and docosapentaenoic acid (n-6 DPA) (OMEGA-GOLD oil). Flax oil contains ALA, and hemp oil is rich in both ALA and GLA. Little information is available about the oxidative stability of these nutritional oils and their bioactive minor constituents. Therefore, this research was initiated to evaluate the oxidative stability of flax, hemp, ARASCO, DRASCO, and OMEGA-GOLD oil, as well as their minor component-stripped counterparts, in the dark at 60°C and under fluorescent light at 2rc. Several analytical methods were used to assess the oxidative stability of these oils. Oil extracts were also investigated for their radical scavenging activity towards the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical by a spectrophotometric method and measuring their total phenolic contents. -- The results indicate that bioactive constituents of these nutritional oils play a major role in their oxidative stability in the dark as well as in the light. However, the fatty acid composition of the oil and the total tocopherols as well as the type of pigments present contribute to their stability. It was found that non-stripped flax and hemp were more stable than their corresponding stripped counterparts. However, non-stripped hemp oil had a higher oxidative stability than non-stripped flax oil as indicated in radical scavenging activity towards DPPH radical and total phenolic contents. On the other hand, DHASCO contains a significant level of natural radical scavengers and phenolic compounds that contribute to its higher stability compared to ARASCO and the OMEGA-GOLD oil. The results demonstrate the importance of minor oil components on their oxidative stability, which will reflect on their food and supplement value as well as shelf life.


identifier: Acharya, Smita <https://research.library.mun.ca/view/creator_az/Acharya=3ASmita=3A=3A.html>   (1977) The influence of low and high level questions and reading ability on achievement in tenth grade social studies.  Masters thesis, Memorial University of Newfoundland.

abstract: The purpose of this study was to determine the effects of different intellectual levels of questions upon the learning of high and low reading ability students. -- Eight grade-ten history classes were selected from the Burin Peninsula Integrated School Board. Each class used the same history unit, however, treatment group 1 (T1) received high-level questions as supporting learning experience, treatment group 2 (T2) received low-level questions as supporting learning experience, and treatment group 3 (T3) received no supporting learning experience. At each treatment there were students of high and low reading ability (determined by Stanford Achievement Test, Form W). A final achievement test was constructed by the researcher and administered to all students at the end of three weeks. The test contained twenty low and twenty high level questions based on the material covered by the questions. -- The statistical procedures used to analyze the data included a 2 x 3 Analysis of Variance, and the Scheffe Method of Multiple Comparisons on the main effects, two 1 x 3 Analysis of Variances and two Scheffe Method of Multiple Comparison of simple effects. -- Analysis of the data revealed that questions are central to learning. The student s working with both high and low questions outperformed the control group. High reading ability students outperformed the Low readers. Furthermore, the high reading ability students seemed to achieve better results when working with high level questions while low reading ability students seemed to obtain best results with low level questions. Both the treatment groups did significantly better than their control group.


identifier: Abedin, S. M. Tareque <https://research.library.mun.ca/view/creator_az/Abedin=3AS=2E_M=2E_Tareque=3A=3A.html>   (2007) Synthesis, structure, magnetism, and coordination chemistry of some self assembled polynuclear clusters and grids of first row transition metal ions derived from polytopic hydrazone ligands.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: A collection of hydrazone based ligands ranging from simple ditopic to pentatopic have been synthesized and allowed to react with different transition metals ions (e.g. Mn(II), Cu(II) ). The ligands varied in terms of their coordination capability (ditopic vs. tritopic ), terminal functional group (e.g.  -NH₂, vs. -CH₃), and overall ligand flexibility (e.g. rigid pyridine vs. -NH central piece). The ditopic ligand (e.g. pomp) gave tetranuclear M(II)₄(M = Mn(II), Cu(II)) complexes when treated with Mn(II) and Cu(II) metal salts. In all of the tetranuclear complexes, metal ions were hydrazone oxygen bridged except for the copper case where Cu(II) centers were bridged by a mixture of N-N diazine and hydrazone oxygen groups. Intramolecular antiferromagnetism was observed in all cases. Tritopic ligands with a flexible secondary -NH central piece yielded mostly trinuclear linear complexes with Cu(II) and trinuclear nonlinear complexes with Mn(II) ions. The inability of this class of ligands to form nonanuclear grids was attributed to the unusual flexible nature of the ligands which is unsuitable for grid formation. Intramolecular antiferromagnetism was observed in all of the trinuclear complexes. Tritopic ligands with pyridine as a relatively rigid center piece (e.g. 2pomp) yielded [3 x 3] nonanuclear Mn(II)₉ grids when reacted with Mn(II). However, with Cu(II) ions this ligand yielded octanuclear Cu(II)₈ pinwheel clusters. All of the Mn(II)₉ grids showed intramolecular antiferromagnetism whereas pinwheels were found to show ferromagnetism, which is relatively rare in this class of polynuclear complexes. Changing the choice to two different donor functional groupings gave two unprecedented outcomes. An oxalic acid dihydrazide based ditopic ligand yielded an inorganic [2] catenane, with mixed oxidation states when reacted with Co(II) ions. This is the first example of an inorganic cobalt catenane. However, due to large metal separations, no magnetic exchange coupling was observed in the complex. In another instance, an extended tritopic ligand formed an enormous Cu(II)₃₆ cluster using the extra coordination capability of the oxime substituents at two ends of the ligand. The cluster showed intramolecular antiferromagnetism. A logical and symmetric extension of the tritopic ligand led to a pentatopic ligand which gave a [5 x 5] square Mn(II)₂₅ cluster. STM imaging techniques were employed to explore the structure of the cluster. Topographic images clearly showed the [5 x 5] square grid-like array on a HOPG surface.


identifier: Acheampong, Edward Asafo-Adjei <https://research.library.mun.ca/view/creator_az/Acheampong=3AEdward_Asafo-Adjei=3A=3A.html>   (1993) Study of the growth parameters of the yeast Phaffia rhodozyma and its production of astaxanthin in peat hydrolysates.  Masters thesis, Memorial University of Newfoundland.

abstract: Salmonid aquaculture as a supplement to the world’s protein resources increased substantially in the 1980s resulting an increase in the market for astaxanthin, the principal carotenoid of salmon. Consumer acceptance of farmed salmonids depends on the color of the flesh. Since fish are unable to synthesize these pigments, they must be supplied to the diet. Currently, synthetic astaxanthin and canthaxanthin are used as pigmenters but there is considerable interest in using biological sources of astaxanthin in the aquaculture industry. – The yeast Phaffia rhodozyma has the potential as an industrial pigment source but its use is limited by the low quantities of astaxanthin in the yeast and also the high cost of growth media. Peat is one of the most abundant and inexpensive resources of the world. The liquid extract from peat contains fermentable carbohydrates which have been used in the production of various microorganisms. – A comprehensive study on the efficiency and yield of the production of yeast biomass and astaxanthin in peat hydrolysate has been carried out by a biotechnological process using Phaffia rhodozyma. The peat hydrolysates used in the present study were prepared by acid and non-acid hydrolyses process at various temperatures ranging from 185-225°C. The sugars present in the peat hydrolysate were determined. The total reducing sugars constitute about 20.66% of the total carbohydrate concentration (TCH). – The substrate concentration that supported the best growth of P. rhodozyma was 30gL⁻¹ for the non-acid hydrolysate and 15gL⁻¹ for the acid hydrolysate. The non-acid hydrolysate produced a dry biomass concentration of 4.04 ± 0.11 gL⁻¹, a yield coefficient of 34.82 ± 0.98% and an efficiency of 13.48 ± 0.1% whilst the acid hydrolysate produced a biomass concentration of 4.30 ± 0.04 gL⁻¹, a yield coefficient of 36.74 ± 1.13% and an efficiency of 14.33 ± 0.1%. These results were obtained at a pH of 7.0, an incubation temperature of 18°C, and a fermentation time of 120 hours. The best inoculum ratio was 5% (v·v⁻¹) and agitation speed was 200 r.p.m. – Of the six peat hydrolysates provided, the acid hydrolysate prepared at a temperature of 185°C (PH4-02-185) was found to support the best growth. The astaxanthin content of the yeast grown in the best acid and non-acid hydrolysates were determined. The acid hydrolysate produced an astaxanthin content of 1567 μg·g⁻¹ yeast. These values compare favorably with those reported by other researchers. – The nutritional requirements of P. rhodozyma grown in the best peat hydrolysate were studied in an effort to enhance the growth and astaxanthin production by this yeast. Organic source of nitrogen were found to promote the growth of and astaxanthin production by the yeast better than ammonium salts of inorganic acids. The addition of increasing concentrations of yeast extract resulted in increase in biomass concentration, yield coefficient, efficiency and astaxanthin content. On the other hand, addition of potassium phosphate to the medium increased the dry biomass concentration but decreased the astaxanthin concentration of the yeast. – Experiments were conducted in 2L fermenters to study the growth kinetics and astaxanthin production by the yeast in peat hydrolysate. The best growth produced a biomass concentration of 4.86 ± 0.12 g·L⁻¹ and an astaxanthin content of 1079 ± 17 μg·g⁻¹ yeast after 120 hours of fermentation. The optimum agitation speed was 250 r.p.m. The optimal aeration required for the production of astaxanthin was found to be 0.5 vvm. Higher agitation speeds reduced biomass production but had no effect on astaxanthin production. Similarly, aeration rates did not have any significant impact on astaxanthin production. The maximum specific growth rate, μmax of the yeast grown in peat hydrolysate was found to be 0.038 h⁻¹. – The chemical composition of the P. rhodozyma cell biomass was analyzed. The crude protein content was found to be 47%, with 5% ash, 19% total lipids, and reasonable amounts of tryptophan, arginine, leucine phenylalanine, threonine, glycine and other amino acids. The yeast was found to contain high quantities of unsaturated fatty acids.


identifier: Adams, Christina <https://research.library.mun.ca/view/creator_az/Adams=3AChristina=3A=3A.html>   (2007) Representations of identity: Canadian girls and pop culture.  Masters thesis, Memorial University of Newfoundland.

abstract: This thesis has no abstract.


identifier: Adams, Marion M. <https://research.library.mun.ca/view/creator_az/Adams=3AMarion_M=2E=3A=3A.html>   (1982) A study of the effectiveness of an instructional unit incorporating the use of the calculator on students' problem solving ability in working with routine word problems.  Masters thesis, Memorial University of Newfoundland.

abstract: The main purpose of this study was to investigate the effect of an instructional unit incorporating the use of the calculator on students I problem solving ability in working with routine word problems. More specifically, the instructional unit I s effect on the number of processes and key processes utilized, the number of correct solutions, and the number of computational errors made was investigated. -- The sample consisted of 10 students enrolled in a grade 10 mathematics course designed for low ability students. The textbook for this course was Consumer Related Mathematics. (Kravitz and Brant, 1971) -- A test consisting of 10 routine word problems was administered to each student individually as a pretest. Students were asked to verbalize their thoughts as they attempted to reach solutions to the problems, and the interviews were recorded on cassette tapes. Following the pretest the results of each student’s performance was coded using the coding sheet. -- A calculator orientation unit and an instructional unit were devised for use in the study. The primary purpose of the calculator-orientation unit was to instruct students on proper calculator usage and the calculator’s relationship to problem solving. A class set of calculators (Model TI-1035) was provided for each class period. The main purpose of the instructional unit was to teach students key processes to be used in problem solving, and how these processes could be applied to different types of problems. The emphasis when teaching the unit was on these key processes with particular attention given to those processes in which students exhibited weaknesses. The duration of the instructional period, including the calculator-orientation unit, was four weeks. Following the instructional unit, students were administered a parallel form of the pretest as a posttest. Students' performances were recorded individually on a cassette tape, and the results coded on the coding sheet. -- Significant gains were reported on a number of key processes utilized by students following instruction. Significant gains were also made in the number of correct solutions. Also, a significant decrease in the number of computational errors made was reported. -- An important observation made from the study was that allowing students to verbalize their thoughts while solving routine words problems provides a basis for instruction directed towards the specific weaknesses of the students involved. Recommendations were made that the study be replicated in other geographical areas, with larger samples and with students of differing abilities. Also the long-term effects of such units need to be investigated.


identifier: Adams, Sara <https://research.library.mun.ca/view/creator_az/Adams=3ASara=3A=3A.html>   (2005) Environmental monitoring of effluent plumes in coastal Newfoundland.  Masters thesis, Memorial University of Newfoundland.

abstract: It is important to first understand the components and fate of an effluent plume in the receiving environment before its effects can be fully understood. The purpose of this work was to identify sensing technologies that can be used to monitor an effluent plume in the coastal environment and use selected sensors to compare the observed results with a predictive model. -- The three major coastal wastewater streams in Newfoundland and Labrador are seafood processing effluent, municipal wastewater and produced water. Each has various properties and components that should be considered when studying the plumes' potential effects. Once an outfall is established in a coastal environment, it is essential to continue monitoring to determine if there are any effects to the receiving environment. Both traditional and in situ sampling can be utilized in this task. Traditional sampling involves the use of bottles or divers to obtain samples at predefined coordinates. In situ sampling refers to the use of continuous sensors on a platform such as an autonomous underwater vehicle (AUV) to obtain measurements instantaneously (or the duration of sensor processing time) without the removal of the specimen or sample. In situ sensors are capable of measuring physical, chemical or biological parameters. -- Seafood processing waste represents the largest source of organic wastes in the province of Newfoundland and Labrador, yet is the least understood. Therefore, it was selected for further study. Trials were conducted at a seafood processing plant in Aquaforte, NL in October, 2004. Measurements were taken with a fluorometer (calibrated to detect rhodamine WT), a CTD sensor (used to measure conductivity, temperature and depth) and a dissolved oxygen sensor mounted on the back of an 18 ft inflatable boat equipped with an electric trolling motor to limit plume disturbance. Continuous spatial data corresponding to sensor information was obtained using a global positioning system (GPS) unit. Spatial and oceanographic data were integrated to obtain a visual and quantitative representation of the plume. -- Temperatures in Aquaforte Harbour were relatively constant with variations within one degree Celsius. Salinity was correlated with temperature and was shown to decrease towards the outer harbour region. Dissolved oxygen values were found to be supersaturated for all trials. Rhodamine WT (RWT) was found to follow a typical plume trend and was used for further plume analysis. -- A comparison of the R WT plume was conducted with the plume dispersion model, CORMIX. It was determined that this type of model can be used to simulate seafood processing wastes given that all the variables in the model are known. The trials were successful in demonstrating the use of this sensor package and dispersion model for monitoring a seafood processing effluent plume.


identifier: Adeoti, Ibraheem Adetunji <https://research.library.mun.ca/view/creator_az/Adeoti=3AIbraheem_Adetunji=3A=3A.html>   (2011) Characterization and alternative use study of fly ash.  Masters thesis, Memorial University of Newfoundland.

abstract: In the generation of power from fossil fuels and biomass, fly ash (FA) is produced and represents both an environmental and economic cost with respect to disposal. However, it also represents a re-use opportunity. Increasing solid waste disposal costs and a focus on sustainable processing necessitates research in alternative uses for fly ash. In this thesis, two ash samples, hog-boiler precipitate ash sample (HBP) and mixed ash pond sample (MAP) from the AV-cell pulp and paper plant were examined for their chemical, physical, thermal, and mineralogical properties. Other physio-chemical properties like density, pH and buffering power were also determined. -- Characterization results were used to determine and test alternative uses for FA. Result shows that the samples are rich source of alum inosilicate, SiO₂, CaO, and Al₂O₃ which are feedstock for adsorption and zeolite synthesis. The concentration of SiO₂ to Al₂O₃ is greater than 1.5 therefore indicating good potential for zeolite synthesis. The FAs pH was between 10.0 and 13.0 with buffering power ranges from 0.5 to 4.9 mmol/pH, as such, were tested for acid mine drainage (AMD) neutralization. Treated effluent water final pH was between 9.0 and 12.2 with contaminant removal efficiency of 85%. Neutralization residue was treated hydrothermally and resulted in an increased adsorption properties zeolite, tested for AMD treatment and yielded above 90% contaminant removal efficiency. The total chemical species (SiO₂ + Al₂O₃ + CaCO₃ + CaO + Na₂O + K₂O + MgO Fe₂O₃) is greater than 90 wt.% hence, the FAs were tested for permeable reactive barriers (PRB) application and its contaminant removal efficiency was also greater than 90% with final treated effluent water pH ranges between 8.4 and 12.2. -- Overall, AMD treatment with FA provides a low cost, environmentally safe and beneficial use of what would be considered a waste.


identifier: Adsett, Daniel Eric Alvin <https://research.library.mun.ca/view/creator_az/Adsett=3ADaniel_Eric_Alvin=3A=3A.html>   (2012) Equivocal transcendence: situating Heidegger's ontology within a medieval schema.  Masters thesis, Memorial University of Newfoundland.

abstract: During the Middle Ages, scholastic thinkers debated the question of whether being is univocal, anaological, or equivocal. Drawing from the tension between Thomistic analogia entis and Scotistic univocity, I argue that Heidegger’s early ontology crosses the boundaries that demarcate this triple distinction between univocal, analogical, and equivocal being. In Heidegger’s ontology, being is univocal insofar as it is considered in itself and analogical insofar as Dasein, non-Dasein entities, and being are concerned, while the relationship between god and being is equivocal. These relationships are, in turn, hierarchically related such that equivocity grounds univocity which is, in turn, more fundamental than analogy. Now, because the equivocal relationship between God and being is more fundamental than the univocity of being, Heidegger’s fundamental ontology is governed by a more primordial commitment to keep God at a distance. Hence, the hierarchy that obtains between the three medieval categories brings into suspicion Heidegger’s allegedly basic ontology. Far from being a neutral articulation of the way being reveals itself, Heidegger’s ontology is, more fundamentally, theologically grounded.


identifier: Ahmad, Masood <https://research.library.mun.ca/view/creator_az/Ahmad=3AMasood=3A=3A.html>   (2013) Affordable filtration technology of safe drinking water for rural Newfoundland and Labrador.  Masters thesis, Memorial University of Newfoundland.

abstract: The main objective of this study is to design a cost-effective filtration system to reduce natural organic matter (NOM) in the intake water source and also to remove trihalomethanes (THMs) and haloacetic acids (HAAs) in the drinking water systems of Torbay and Pouch Cove communities near St. John’s. To reduce the concentration of THMs and HAAs, a series of experiments were conducted on tap water using an inexpensive adsorbent. The results showed more than 95% removal of THMs and 35% of HAAs in the Pouch Cove drinking water using activated carbon. Another test was conducted with clean carbon without activation which shows significant removal of chloroform, bromodichloromethane, and bromoform in the THMs group and a high percentage removal of bromchloracetic acid, dichloroacetic acid, trichloroacetic acid, and dibromoacetic acid in the HAA group. Clean carbon was also used to remove total organic carbon (TOC) in the intake water source before chlorination. The results showed more than 92% removal to TOC from Pouch Cove and 65% removal from the Torbay intake water. The results showed that the formation potential of THMs and HAAs are significantly reduced due to low TOC values in the filtered water and low-cost adsorbent can be used as an effective adsorbent to supply safe drinking water to rural communities.


identifier: Ahshan, Razzaqul <https://research.library.mun.ca/view/creator_az/Ahshan=3ARazzaqul=3A=3A.html>   (2013) Renewable sources based micro-grid control schemes and reliability modeling.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: This thesis has no abstract.


identifier: Ahuja, Sunil <https://research.library.mun.ca/view/creator_az/Ahuja=3ASunil=3A=3A.html>   (1984) Dynamic balancing of rotors supported on fluid film bearings using finite element analysis.  Masters thesis, Memorial University of Newfoundland.

abstract: This thesis presents a comprehensive analysis of a multi-rotor bearing system, that includes realistic end support conditions. It provides a design engineer with the present day technology available in carrying out a balancing analysis. The design is based on minimizing the flexural response, due to mass unbalance. -- The model is developed based on the finite element approach which provides a convenient and accurate means of balancing a rotor-bearing system. The model incorporates the effects of translational, and rotational inertia, and gyroscopic moments, using the consistent matrix approach in conjunction with dynamic matrix reduction technique, modal analysis, and least-square balancing technique. The use of matrix reduction technique for determining a equivalent reduced system, provides subsequent saving of both computational time and space on the digital computer. This allows modelling of complex rotor system conveniently, while retaining only those degree of freedom essential to the solution of the problem. The modal analysis used is an effective means of determining the unbalance force response, for systems with unsymmetric stiffness and damping matrices. The least-square method for balancing, is used to include balancing cases where the number of measuring lanes exceeds the number of balancing planes. This represents most actual balancing situations, and allows an increase in the input data, whereby the consequence of a single error in data tends to decrease. The balancing at one speed is usually sufficient to bring the rotor amplitude down over its entire speed range. Further, flexibility in rotor balancing is provided by including the effect of varying the location, and number of balancing planes.


identifier: Akbarali, Hamid I. <https://research.library.mun.ca/view/creator_az/Akbarali=3AHamid_I=2E=3A=3A.html>   (1987) A pharmacological study of some relaxation processes in the rat oesophageal tunica muscularis mucosae.  Doctoral (PhD) thesis, Memorial University of Newfoundland.

abstract: This thesis deals with pharmacological properties of rat oesophageal smooth muscle, viz. the tunica muscularis mucosae (TMM). Although the TMM contains the bulk of smooth muscle of the rodent oesophagus, its function is not fully understood. However, recent evidence supports an active role for the TMM in oesophageal motility. Present concepts of the processes involved in oesophageal peristalsis have emphasised the importance of neural inhibitory mechanisms in the smooth muscle layer of the oesophagus. The present study was thus chiefly concerned with relaxation responses of the TMM. -- The presence of a submucous ganglionated plexus in the isolated TMM was demonstrated by histological examination. The nerve plexus was found to contain acetyl- and butryl-cholinesterases and various peptide immunoreactive nerve fibres such as vasoactive intestinal peptide and calcitoningene related peptide. Adrenergic innervation was sparse in the proximal and supradiaphramatic portion of the TMM; serotonin was observed to be localised to mast cells but not to nervous elements. -- In the presence of cholinoceptor-induced tone relaxation responses were elicited in the TMM by field-stimulation and by stimulation of the vagus provided excitatory responses to electrical stimulation were blocked. Relaxations were also examined to pharmacological agents. -- Field-stimulation of the isolated TMM produced both a tetrodotoxin (TTX) -sensitive and TTX-insensitive relaxation. The former was sensitive to guanethidine in the distal but not in the proximal segment. The TTX-insensitive response was unaffected by a variety of pharmacological agents and not abolished by cold storage. It was however diminished by cooling and by calcium antagonists. This form of relaxation was characterised as purely myogenic and a consequence of K⁺ efflux activated by calcium entry through potential-operated channels following field-stimulation. Vagally-stimulated relaxations in the whole oesophagus preparation were insensitive to hexamethonium. Relaxations to pharmacological agents such as 5HT and A23187 were found to have a regional gradient with the proximal TMM segments being more responsive than the distal segments. -- This study demonstrates that the isolated TMM with its attached submucous plexus is capable of relaxing to both electrical and pharmacological stimuli.


identifier: Akbari, Babak <https://research.library.mun.ca/view/creator_az/Akbari=3ABabak=3A=3A.html>   (2011) Polycrystalline diamond compact bit-rock interaction.  Masters thesis, Memorial University of Newfoundland.

abstract: A physical model of a single PDC (Polycrystalline Diamond Compact) cutter interacting with rock surface is developed, and its most important characteristic is the ability of inputting different force on cutter profiles and outputting cutter penetration. The model is developed in 2 dimensions simplifying the three dimensional cutter movement by a 2 dimensional plane. The model is simulated using the Distinct Element Method and simulation results for the single cutter are interpreted. Simple theories are then proposed to extend the results to a full PDC. -- Model inputs encompass parameters such as force profile and horizontal velocity profile on the cutter and also pressure on the rock specimen and the model outputs include dynamic parameters such as cut depth and penetration profile and energy consumed by the cutter. -- Relating different types of model inputs and outputs to drilling operational parameters is explained. Approaches to tackle a certain drilling problem relating to the efficiency of particular down-the-hole tools exerting dynamic force profiles on the bit using this model are also explained in detail. -- Results show that adding force oscillation generally improves the drilling performance; however, the improvement diminishes as the bottomhole pressure increases. Also, regardless of the force oscillations, the rate of penetration decreases linearly with logarithm of the bottomhole pressure.


identifier: Akinnola, Ayobamidele Philip <https://research.library.mun.ca/view/creator_az/Akinnola=3AAyobamidele_Philip=3A=3A.html>   (2005) Bioremediation of diesel contaminated soil using biostimulation, bioaugmentation and bulking agents.  Masters thesis, Memorial University of Newfoundland.

abstract: Petroleum hydrocarbons account for approximately 60% of contaminated sites in Canada. Atlantic Canada, especially in the Eastern region of the Province of Newfoundland and Labrador, which is known for quite a number of hydrocarbon-contaminated soils. Laboratory experiments in two phases were undertaken to compare the influence of nutrients, inocula and bulking agents additions on the bioremediation of diesel-fuel contaminated soil over a 90-day testing period. Phase I experiments determined the effect of one type of nutrient (either poultry manure or liquid cow manure), one type of inoculum (either indigenous or exogenous microbial inoculum) and one type of bulking agent (either sand or hay) on the degradation of diesel fuel in soil. Phase II experiments involved a series of laboratory-based experiments conducted to study the interactions among the nutrients, inocula and bulking agents additions. -- After a 90-day experimental period, 96.6% degradation was achieved in contaminated soil containing clean Ottawa sand as a bulking agent in phase I experiments while 96.2% degradation was achieved in contaminated soil containing an inoculum of soil indigenous microbes and clean Ottawa sand in phase II experiments. The biodegradation results were analyzed to determine the most significant factors and interactions using Design-Expert® version 6 software for Design of Experiments. Additions of nutrients and bulking agents was found to be statistically significant, while the addition of inocula and the interactions among the nutrients, inocula and bulking agents were statistically significant.