VictorJuiz/thesis huggingface dataset:
Hypersonic fuel/air mixing enhancement by cantilevered ramp injectors in the presence of wavy walls

In an effort to develop hypersonic air-breathing propulsion systems wavy walls were added to a cantilevered ramp injector to increase the fuel/air mixing in a shock-induced combustion ramjet (shcramjet) engine. Numerical studies of various wavy wall configurations in the vicinity of the cantilevered ramp injector were undertaken using three-dimensional, multispecies Navier-Stokes solvers. Laminar simulations established the amplitude of the wavy walls has a much greater influence upon the resulting flow field than the wall wavelength. The mixing initially increases with amplitude and then decreases as the shocks formed from the wavy wall disrupt the main mixing vortices in the flow. The addition of wavy walls allows for an increase in mixing efficiency of approximately 10%, but in the best case incurs the same degree of losses. Subsequent turbulent studies demonstrated similar flow fields to the laminar cases, with greater the mixing due to increased diffusion, but at the cost of greater losses. As such the mixing efficiency vs. total pressure loss ratios found in the turbulent cases are worse than those found in the laminar cases. It was also found that the effect of the wavy wall is reduced with increasing boundary layer height, but the mixing is augmented due to greater dissipation in the slower flow. This study suggests the addition of wavy walls to cantilevered ramp injectors may not be desired, since they do not provide a significant benefit with minimal detrimental effects.
The effect of temperature on the electrical resistivity of electrodeposited nanocrystalline materials

The electrical resistivity as a function of temperature (4K to 773K) of several electrodeposited nanocrystalline materials (Ni, Ni-Fe, Co) has been examined. The contribution of the grain boundaries to the electrical resistivity was quantified in terms of a specific grain boundary resistivity, which was found to be similar to previous reported values of specific grain boundary resistivity of copper and aluminum obtained from studies involving polycrystalline samples. In the high temperature range, the resistivity of the nanocrystalline samples was monitored under both isokinetic and isothermal heating. A Kissinger type analysis was applied using the temperature corresponding to the maximum rate of change of the resistivity under isokinetic heating at various heat rates. The activation energies calculated by this method were found to be similar to those determined on similar materials using conventional differential scanning calorimetry. The observed time dependence of the resistivity measured isothermally at elevated temperatures was correlated to microstructural changes in the material using the specific grain boundary resistivity. A model involving abnormal grain growth is introduced to explain the resulting shape of the grain growth vs. time curves. This study has shown that electrical resistivity is an excellent characterization tool for nanocrystalline materials giving useful information regarding grain size and degree of thermal stability, as well as some insight into the grain growth kinetics at the various temperatures.
How stimulus dimensions and task requirements affect the focusing of attention

The size of an attended area has been shown to impact processing efficiency (e.g., Castiello & Umilta, 1990); the larger the focus-area, the slower the reaction time (RT) to targets in that area. This study examined the pattern of focus-size effects through a wide range of cue sizes. Experiment 1 failed to find a focus-size effect with either a discrimination or detection task. To determine if a focus-size could be found, Experiment 2 replicated an earlier study (Maringelli & Umilta, 1998) that included more stimulus onset asynchronies (SOAs) and fewer cue sizes than the first experiment. An effect of focus-size was found with the short SOAs, however with half the strength as the original study. Experiment 3 was a modified version of the first experiment, with fewer cue sizes and shorter SOAs. As in the second experiment, a small focus-size effect was found for the middle range of the cue sizes. Overall, the focus-size effect was smaller and weaker than expected, suggesting that the methodological approach and current theorizing of the effect should be further examined.
Some mathematical problems in inhomogeneous cosmology

This thesis deals with two main topics: Matchings of certain space-times in general relativity, and searching for new, exact solutions of Einstein's field equations by using the intrinsic symmetries approach. In the first part of this thesis we investigate the matchings of Friedmann-Lemaître-Robertson-Walker (FLRW) space-times with a Kasner vacuum region. It is already known that a spatially flat FLRW space-time can be joined smoothly to a Kasner vacuum space-time. We extend this result to an open FLRW metric, by explicitly constructing a matching across a three-dimensional hypersurface using the Darmois junction conditions. We then introduce a non-zero cosmological constant and show that its presence has no significant effect on the matchings. We also prove that it is possible to match a certain class of Szekeres solutions to a closed FLRW space-time. This might not be intuitively obvious, since Szekeres's space-times have no symmetry (no Killing vectors), while FLRW space-times are highly symmetrical. In the second part of this thesis we apply the idea of intrinsic symmetries (symmetries operating on three-dimensional submanifolds of space-time rather than on the space-time itself) to search for new inhomogeneous solutions to the field equations. We consider metrics which posses 'a priori' planar symmetries on three-dimensional time-like hypersurfaces. In the vacuum case no new solutions were found, the only solution being the Minkowski space-time. In the non-vacuum case we assume a perfect fluid matter content and a fluid flow orthogonal to the three-spaces 't' = const., and obtain two exact inhomogeneous classes of solutions belonging to the Szekeres-Szafron family of solutions. In addition, we also present coordinate transformations for obtaining an open FLRW metric in a plane symmetric form.
Brave new worlds?, the gender politics of Margaret Cavendish's primary and secondary realms

This thesis tests whether the theory that estrangement allows reconceptions of gender politics holds in the liminal and secondary worlds of Margaret Cavendish, a writer deeply, if ambivalently, committed to Fancy. Her work is often subversive, but withdraws when the social order is threatened. In order to assess whether Cavendish's gender politics change in her secondary worlds, her primary-world work must first be examined. Here, Cavendish is contradictory on female nature, education, public authority, speech, cross-dressing, and marriage, reflecting her multiple and divided concept of subjectivity. She always remains committed to female chastity and obedience, however, and to social order. Relationships between women are also consistently problematic in her primary-world work. This does not completely change in her liminal worlds. The feminocentric imaginative worlds or new societies of 'The Convent of Pleasure, Lady Contemplation', and 'The Female Academy', all become unstable, only surviving if they carefully negotiate with the primary world. In 'Blazing World', the Empress reforms its misogynist religion and government, but change threatens this utopia's stability, and the Empress apparently withdraws her reforms. The 'Blazing World' finally becomes an ambivalent text on female rule and nature, despite the discursive and educational spaces created for women and the celebration of female friendship. In contrast, the more stable world of "Assaulted and Pursued Chastity" does not fundamentally attempt to challenge gender politics, although the text radically realigns gender and genre, destabilizes sex and gender (if only in terms of the protagonist), and women finally become good rulers. If subversiveness is kept within careful bounds, recuperation becomes unnecessary. Aemelia Lanyer, Rachel Speght, and Anne Bradstreet also experiment with the opportunities available for women in fantasy, but the primary world often destroys these liminal and secondary worlds, showing a feminine vulnerability to Fortune. In contrast, the pragmatic Aphra Behn dismisses secondary worlds. Reflecting the ephemerality of feminine fancy, Cavendish's secondary and liminal worlds only occasionally depart from the contradictions inherent in her gender politics in the primary world.
Ras-mediated mitogenic and angiogenic signaling in human astrocytomas, a novel therapeutic target

Diffuse astrocytomas are the most common primary malignant tumours of the central nervous system, and carry a dismal prognosis. With varying frequency, these tumours are characterized by the deletion or functional inactivation of various tumour suppressor genes ('p53', pRb, p16, ' PTEN'/'MMAC1, DMBT1', and putative tumour suppressor genes on chromosome 10 and 19q). Furthermore, they are characterized by the overexpression of Platelet-derived Growth Factor Receptors (PDGFR) and their cognate ligands, the amplification and overexpression of the Epidermal Growth Factor Receptor (EGFR), the expression of a constitutively phosphorylated truncated EGFR (EGFRvIII), and overexpression (with or without amplification) of 'MDM2, c-myc, N-myc', and 'CDK4'. Finally, they are characterized by their extensive neovascularization. We have proposed that despite the absence of activating 'Ras' mutations in these tumours, the overexpression of PDGFR, EGFR, EGFRvIII and other receptor tyrosine kinases functionally activates the Ras signaling pathway. In the present thesis, we demonstrate that astrocytomas demonstrate activation of the Ras signaling pathway, and that inhibition of this pathway results in impaired tumour growth. The development of putative Ras inhibitors, including farnesyl transferase inhibitors (FTIs), has generated tremendous interest; we demonstrate that astrocytomas appear to be a rational target for FTIs.
The operation of whiteness and forgetting in Africville, a geography of racism

In the 1960s the City of Halifax dismantled the black community of Africville under a program of urban renewal and 'slum clearance'. Africville's 400 residents were evicted from their homes, in many cases receiving insufficient financial compensation. From that time on, the City has defended its actions by citing the deplorable living conditions in Africville, obscuring its own creation of these conditions through years of neglect and the refusal of essential services. In the 1980s, the space of Africville was made into a public park, which remains a site of contestation, protest and commemoration. The City of Halifax continues to deny financial compensation to former residents, has never issued a public admission of wrongdoing and has actively maneuvered to silence protest. This dissertation traces the events around this history as a chain of evictions of Africville from its own space. The regulatory measures taken by the city of Halifax are theorized as a series of choices--rather than inevitably necessary moves--which constituted Africville in various ways: as a slum, then as a 'problem' which was solved, and more recently as a white communal space in which past violence is rendered invisible. The aim of my analysis in this work is not an explication of the experiences of Africville residents, or of the experience of African Canadians in general, but rather a critical mapping of the actions of the white municipality of Halifax in Africville's history. I argue that these acts of regulation of black spaces and bodies logically follow one another in creating a 'geography of racism'. In tracing the continuing management of space over time, I demonstrate how whites in positions of privilege and authority come to know themselves as legitimately dominant. In critiquing the effective erasure of racism and violence in the white story of Africville, I illustrate how these dominant social actors construct their innocence through particular forms of commemoration.
Scattered data interpolation using an alternate differential equation interpolant

We investigate the performance of DEI, an approach [9] that computes off-mesh approximations of PDE solutions, and can also be used as a technique for scattered data interpolation. We compare the new approach with two methods from the collection of ACM algorithms: Algorithms 752, and 790. For the general case of unstructured meshes, we found it necessary to modify the original DEI. The resulting method, ADEI, adjusts the parameter of the interpolant, obtaining better performance. Finally, we measure ADEI's performance using different sets of scattered data and test functions. The results show that ADEI is better if not comparable to the best of the available scattered data interpolation techniques.
Stratigraphy and mineralization of the Bongara MVT zinc-lead district, northern Peru

The Bongara MVT zinc-lead district is located in the sub-Andean fold-and-thrust belt of the northern Peruvian Eastern Foreland Basin. Lower Mesozoic Pucara Group carbonates form a craton-margin platform that represents the first marine transgression of the Andean Cycle. The northern Pucara Group developed discordantly over piano-key shaped horst-and-graben terrestrial sequences formed under extensional tectonic conditions. Lithofacies differences within the Pucara Group are a result of deposition along paleogeographic basement highs through the Utcubamba Valley. MVT-style zinc-lead mineralization is hosted within Pucara carbonates associated with pervasive dolomitization, pseudobrecciation, and structural zones of carbonate dissolution. Mineralization is predominantly sphalerite, galena, and pyrite observed as replacive and open-space filling textures. The paragenetic sequence includes early burial and compaction-related carbonate cements, and later diagenetic/epigenetic zoned sparry dolomite and calcite. Petrographic and isotopic analysis suggests that early and late diagenetic alteration associated with mineralization occurred through an interconnected, district-wide, structurally controlled plumbing system.
Coping strategies and well-being during adolescene and early adulthood

The coping strategies of adolescents and young adults were examined to: (a) determine the patterns of coping in this population; (b) investigate developmental influences (e.g., age, gender, race, and SES) on the use of coping strategies; and (c) examine the relationship between coping and well-being. 128 participants completed a semi-structured interview assessing their use of coping strategies during their own stressful life event. Significant age, gender, and race effects were found in the type of, and frequency with which, coping strategies were used. Young adults reported using more positive cognitive restructuring whereas adolescents used more problem-focused support. Race effects indicated that African Americans used avoidant actions more than Whites. Gender adherence to cultural expectations and socialization were found; males more frequently endorsed active coping whereas females more frequently endorsed support-seeking coping. Significant correlations were found between coping styles, coping resources, and well-being.
Modelling, routing and architecture in active networks

This dissertation proposes a new cost model for active networks and employs it to develop novel active routing and agent placement algorithms. In addition, a new architecture for deployment of active network nodes IS proposed which transforms almost any Internet host into an active node using the Java Virtual Machine embedded in the host browser. Cost models implied or expressed in passive networks do not take into account the processing performed at nodes and the alterations of the flows from hop to hop. Furthermore, the roles of network nodes and flows change in the active network paradigm. No longer do the nodes alone compute and enforce the network routes in an indiscriminate fashion. The active packets or flows decide their own routes only with assistance from the network nodes. Through implementations of network mechanisms such as routing, connection admission and reservation, I show the need for and the advantages of the proposed cost model. A practical and flexible active routing algorithm developed based on this model optimally places active processes or agents on the internal nodes of the network to minimize the total end-to-end cost of the flow. Finally, Java applets and Java-enabled web browsers are combined to transform any Internet host to an active node instantly. This approach, which requires no hardware or software installation, forms the basis of successful deployment and test of an interactive service. The power of this ubiquitous approach lies in its potential to expand the coverage of active applications rapidly and seamlessly.
A comparison of stochastic separated flow models for particle dispersion in turbulent flows

This thesis investigates Stochastic Separated Flow (SSF) models for particle dispersion in turbulent flows. A new model is presented that incorporates a temporal and a spatial autocorrelation in the description of the fluctuating component of the turbulent gas-phase velocity. This model and four SSF models available in the literature are evaluated analytically and by comparing predictions with the grid-generated turbulence experiments of Snyder and Lumley (1971), and Wells and Stock (1983). Results are discussed and deficiencies in the models explored. The new model of Hennick and Lightstone compensates for the crossing trajectory effect with the inclusion of a spatial correlation based on the relative velocity of the particle and the timestep employed. Promising results are obtained using this model.
Community participation in educational reform, a Jamaican experience

There is growing acceptance in the field of education that the home-school relationship is a crucial and integral factor in the effective management of schools, and the overall education change process. This issue has become relevant to the Jamaican education context due to the education reform process now underway, which is exploring alternative and effective means of educational management. In addition, parents and school officials are also demanding that the education process be more effective and representative. This thesis aims to explore the issue of community and parental involvement in the reform process of the Jamaican system of education. The research will address the following issues: (1) What is the value and effectiveness of community and parental involvement in the process of school management at the institution to be studied? (2) What measures or strategies are in place to encourage and strengthen the home-school relationship? (3) What are some of the challenges hindering the home-school relationship? (4) What strategies can be recommended to address the challenges, and strengthen the home-school relationship, and the overall management of the school system in question? It is hoped that the findings rendered from this research will provide valuable insight and practical recommendations to the school administration at the research site; and also serve as a guide to educational policy-makers and practitioners as they attempt to enhance and strengthen the home/school relationship, a significant educational benefit.
Factual matters, visual evidence in documentary fiction

This study examines the use of visual evidence in documentary fiction and considers its relation to issues of rhetorical argumentation, epistemological value, and belief. Taking into account both the factual and fictional components of this genre, particular attention is given to the interface between visual documents that appeal to the "real" and documentary fiction's subversive narrative techniques that force into admittance the constructed and fictional nature of such documents. It is argued that the interplay between the "real" and the artificial is what incites readers of documentary fiction to belief. In the documentary fictions chosen for this study, visual evidence both reflects and functions alongside the narrative's fundamental concern for accuracy and truth as well as its overt declarations of fictionality. Because documentary fiction admits the incongruity between what is and what is documented, readers are encouraged repeatedly to shift referential criteria from the external correspondence with the factual world to the internal coherence of the fictional text. Indeed, the paradoxical unity of factual event and fictional reconstruction encourages readers to engage in interpretative manoeuvres that reflect most directly the union of historical reality and imaginative speculation that informs the truthfulness of all documentation and shapes its power to impart meaning. The evidential images incorporated in documentary fictions are epistemologically sound precisely because they simultaneously stand as visual testimony of a precise historical moment and entice readers towards the creation of a fantastic historical past. Visual evidence is introduced into the narrative fabric of many documentary fictions in order to establish more forcefully the collusion between objective reality and fictional reconstruction that informs truth.
Biologic properties of platelet-derived microparticles, characterization of mechanisms of generation and adhesion

Platelet-derived microparticles (MP) are procoagulant membrane microvesicles generated upon platelet activation and observed in thrombocytopenic and thrombotic clinical states. The mechanism of MP formation and their adhesive properties are poorly understood. We characterize the roles of fibrinogen, its binding peptides and GPIIb/IIIa receptor in thrombin induced human platelet MP formation utilizing flow cytometry. Further, we characterize and compare platelets and MP adhesion to surface-bound ligands (fibrinogen, fibrin and collagen type I) using a unique, static, microsphere based adhesion assay, flow cytometry and scanning electron microscopy. MP formation was metal ion, fibrinogen and GPIIb/IIIa dependent. Specific GPIIb/IIIa reagents (antibodies, drugs) and fibrinogen peptides (RGDS, H12) and antibodies fully abolished MP formation. MP adhesion to immobilized vascular ligands was metal-ion dependent and receptor-ligand specific. In conclusion, fibrinogen (RGDS, H12) and GPIIb/IIIa are absolutely required for thrombin induced MP generation. Further, MPs adhesion to fibrinogen, fibrin and collagen-coated surfaces is mechanistically similar to that of platelets.
Hegel's critique of the concept of consciousness, its relevance to contemporary epistemology and philosophy of mind

This study develops a particular interpretation of G. W. F. Hegel's ' Phenomenology of Spirit', and extends it to contemporary philosophical concerns. I claim that the 'Phenomenology' is a critique of an epistemic concept, 'consciousness', and that the 'Phenomenology ' should therefore be viewed generally as a critique of mentalism. 'Mentalism' refers to both a body of beliefs and certain habits of thought that presuppose the subjectivity of mind, and that picture mind and mental items as standing in a problematic relation to what is taken to be the objectivity of reality. I claim that the interpretation of Hegel as a critic of mentalism clarifies Hegel's overall systematic intentions, and therefore clarifies the relation of the 'Phenomenology' to the 'Science of Logic'. I argue that the reading of Hegel that is developed here is relevant to contemporary philosophy. I examine works by John McDowell, Robert Brandom, and Ludwig Wittgenstein. I draw analogies between Hegel and the later Wittgenstein, who I claim was also a critic of mentalism. I argue that insofar as Hegel and Wittgenstein are critics of mentalism, it is a significant error to read either of them as espousing any form of idealism.