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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

The Effects of Compressibility on the Propagation of Premixed Deflagration

Fecteau, Andre 11 July 2019 (has links)
The thesis addresses the influence of compressible effects on the stability of deflagration waves. Due to the quasi-isobaric nature of slow flames, compressible effects in laminar flames are usually neglected. Nevertheless, turbulent deflagrations may propagate at substantially higher speeds, suggesting that compressible effects may play a role in their dynamics. In the present thesis, the stability of diffusion-dominated high-speed deflagrations is addressed. The deflagration is studied in the thickened regime, hence addressing the long wavelength limit of these deflagrations. The deflagrations are modelled by the compressible reactive Navier-Stokes equations with a single-step Arrhenius reaction model. The 2D stability of the steady traveling-wave solution is studied by direct simulation. It is found that, as the flame compressibility becomes significant, not only does the growth rates of the cellular profile of the deflagration waves increase, but the traditional correlation of the burning velocity and the flame surface area become far less strong. Significant compression regions form in front of the nonlinear flames. These compression regions have been found to increase the growth rates by increasing the temperature of the unburned gas in front of the flames, as well as convecting the flame forward. The results show that the flame propagation velocity in references to the unburned gas was significantly faster than the burning velocity. The vorticity was given consideration, as the compressibility of flame increase one can expect the baroclinic source to be of greater significance. The vorticity was show to, in effect, increase as compressibility increases while unexpectedly having a stabilizing direction of rotation on the cellular structure of the flames.
202

Approaches to new DNA-repair inhibitors for applications in cancer therapy

Dhami, Archana January 2008 (has links)
5-Aminoisoquinolin-1(2H)-one hydrochloride (5-AIQ.HCI) is a potent, water-soluble PARP-1 inhibitor that exhibits outstanding activity in a wide range of disease models in vivo. The aim of this project is the design and synthesis of derivatives with substituents at the 4-positoin of 5-AIQ. The modes of cyclisation of methyl 2-(substituted)alkynyl-3-nitrobenzoates with different electrophiles (ICI, PhSeCI, HgSO4) were studied. The exclusive formation of isocoumarins demonstrates the influence of the nitro group in directing electrophile-driven cyclisations towards the 6-endo-dig mode. The crystal structure of 5-nitro-3-phenyl-4-phenylselenylisocoumarin showed intermolecular and intramolecular ?-stacking. Attempted synthesis of 4-benzyl-5-nitroisoquinolin-1-one by selective reduction of the nitrile of methyl 2-(1-cyano-2-phenylethyl)-3-nitrobenzamide failed. Bromination of 5-nitro-isoquinolin-1-one gave 4-bromo-5-nitroisoquinolin-1-one but Pd(0)-catalysed cross-couplings (Stille, Sonogashira, Suzuki-Miyaura) of this and of 4-bromo-5-AIQ failed. An alternative approach was Pd-catalysed cyclisation of N-(2-alkenyl)-2-iodo-3-nitrobenzamides. Reaction of N,N-diallyl-2-iodo-3-nitrobenzamide with Pd(PPh₃)₄ gave 2-allyl-4-methyl-5-nitroisoquinolin-1-one and 2-allyl-4-methylene-5-nitro-3,4-dihydro-isoquinolin-1-one. N-Benzhydryl-N-cinnamyl-2-iodo-3-nitrobenzamide gave 2-benz-hydryl-4-benzyl-5-nitroisoquinolin-1-one and 2-benzhydryl-4-benzylidene-5-nitro-3,4-dihydroisoquinolin-1-one. These products are not interconvertible. The secondary amides N-allyl-2-iodo-3-nitrobenzamide and N N-((substituted)-cinnamyl)-2-iodo-3-nitrobenzamide gave good yields of the required 4-methyl- and 4-((substituted)-benzyl)-5-nitroisoquinolin-1-ones, respectively, under optimised conditions (Pd(PPh₃)₄, Et₃N, Bu₄NCI, 150°C, rapid heating). Hydrogen gave 4-methyl- and 4-benzyl-5-amino-isoquinolin-1-ones. The 4-substituted 5-AIQs were evaluated for inhibition of recombinant human PARP-1 activity. Three were more potent than 5-AIQ; 5-amino-4-methylisoquinolin-1-one (IC₅₀ = 0.25 μM), 5-amino-4-benzylisoquinolin-1-one (IC₅₀ = 0.5 μM) and 5-amino-4-bromoisoquinolin-1-one (IC₅₀ = 1.0 μM).
203

An assessment of the physical fitness demands of one day cricket using global positioning system tracking software

Webster, Zane January 2017 (has links)
Magister Sport, Recreation and Exercise Science - MSRES / Cricket is a highly technically skilled-based game, which consists of four distinct disciplines (batting, bowling, fielding, and wicket keeping) with varying physiological and biomechanical demands. There are three standardized professional versions of the game, namely, test match or multi-day cricket, limited overs or one-day cricket and Twenty-20 or T20 cricket. One-day games consist of two innings with each team getting a chance to bat and bowl. One innings encompasses fifty overs and the game generally lasts for approximately 6 hours. Although research has been conducted on the physical demands of cricket, not many studies compare the differences of these demands between different playing positions. Furthermore, there is a lack of research around the differences between professional and amateur level cricket players.
204

Ring-opening polymerisation of 1,3-Dioxolan-4-ones

Cairns, Stefan Alexander January 2018 (has links)
Polyesters have been realised as a viable replacement for slow or non-degrading petroleum derived polymers. A variety of aliphatic polyesters, e.g. poly(lactic acid), have received a lot of attention because they are produced from renewable feedstocks and have the ability to biodegrade and bioassimilate. Poly(lactic acid)'s broader family, poly(α-hydroxy acid)s, have been produced with a wide variety of properties, that has given polyesters the potential for a more diverse range of applications. However, their synthesis has proven difficult. This thesis investigates a family of 1,3-dioxolan-4-ones as a monomer source to ease difficulties in current synthetic routes. Polymerisation of the parent 1,3-dixoxolan-4-one was tested. The copolymerisation of Llactide and 1,3-dioxolan-4-one was conducted with various monomer feedstocks. Ringopening polymerisation of 1,3-dioxolan-4-one led to the formation of paraformaldehyde as a polymerisation by-product. The copolymerisation was found to be best controlled when using a coordination-insertion type catalyst. 1,3-dioxolan-4-one was also copolymerised with ε-caprolactone and β-butyrolactone to produce copolymers with various compositions. The formation of poly(lactic acid) and poly(mandelic acid) from 5-methyl-1,3-dioxolan- 4-one and 5-phenyl-1,3-dioxolan-4-one was investigated. Poly(lactic acid) and poly(mandelic acid) were synthesised with either isotactic or atactic tacticities. Molecular weights were found to be lower than the expected values. A variety of MeAl(salen) catalysts were explored for the polymerisation of 5-methyl-1,3-dioxolan-4-one and catalysts ligated with tertiary-butyl substituted salens were found to have higher rates of polymerisation and reached high conversions. Altering the diimine bridge in the ligand led to variations in rates of polymerisation and molecular weights. The cause of the decrease in molecular weight was found to be caused by a side reaction. The side reaction was bypassed by polymerising 2,2,5- trimethyl-1,3-dioxolan-4-one and 2,2-dimethyl-5-phenyl-1,3-dioxolan-4-one to form poly(lactic acid) and poly(mandelic acid), respectively, with the expulsion of acetone. The scope of 1,3-dioxolan-4-ones capable of being polymerised to form poly(α-hydroxy acid)s was expanded to include iso-propyl, cyclohexyl, normal-butyl, iso-butyl, propargyl, chloromethyl and benzyloxymethyl substituents at the five position. The glass transition temperatures accessible from this synthetic route was expanded (22-105 °C). Kinetic experiments revealed the impact of the substituents steric bulk on the rate of polymerisation and points toward a coordination-insertion mechanism. Poly(lactic acid-co-glycolic acid) was copolymerised with 5-propargyl-1,3-dioxolan-4-one to incorporate alkynyl functionality and hence Raman spectroscopy showed the polymer had a distinct peak at 2128 cm-1. Following post-polymerisation modification of poly(lactic acid-co-3-chloro-2-hydroxypropanoic acid) copolymers, acrylate functionalised polymers were produced. The copolymers were shown to be capable of crosslinking poly(α-hydroxy acid) and poly(methyl methacrylate).
205

Alexander Scriabin's style and musical gestures in the late piano sonatas : Sonata No.8 as a template towards a paradigm for interpretation and performance

Seah, Stefanie Huei-Ling January 2011 (has links)
Alexander Scriabin's piano sonatas are largely regarded as the most significant works in the genre since Beethoven. They outline the development of his compositional style from the youthful Chopinesque works, to his mature, idiosyncratic post-tonal offerings. According to his close friend, biographer, and critic Leonid Sabaneyev, despite Scriabin's philosophy suffering “from too many manifest faults”, his late music is “incomprehensible and incomplete” when “severed from his philosophy”. Consequently, this treatise focuses on Scriabin's unique compositional voice through an examination of his idiosyncratic musical gestures, and the points of their interaction/intersection with his eclectic philosophizing. Recognizing the absence of a substantial interpretive system that reconciles Scriabin's music with his philosophical outlook in the available Scriabin-scholarship, this dissertation investigates the impact of his mystical beliefs upon his compositional style. This is largely achieved through the identification and scrutiny of symbolic gestures in his idiosyncratic pianistic style. Part 1 constitutes the examination of Scriabin's symbolic gestures that routinely feature in his late works: unity, summons, light, flight, occult, resonance, sensuality, eroticism, ecstasy, and transformation/dissipation. Part 2 discusses Sonata no.8, which stands to benefit the most from a gestural reading, due to the near absence of the composer's customary vivid French annotations. A brief discussion regarding issues of interpretation and performance of that sonata and Scriabin's late keyboard works completes this dissertation. The investigative method outlined above, in synergy with the composer's complex beliefsystem, develops a new gestural framework for perceiving and interpreting Scriabin's work; one that blurs the conventional distinctions between musicologist and performer, enabling informed conceptualizations and gestalt performances of these ‘symbolist' works. Sonata No.8 is used as a matrix upon which this theoretical approach is applied. Through relative comparisons and references to the other late sonatas, the Eighth is proffered as an interpretive model upon which analogous interpretations may be based.
206

Trench modernism : William Orpen's career as war artist

Cuzman, Miruna Sinziana January 2015 (has links)
In response to growing German propaganda during the First World War, the British Government formed a special Propaganda Department, which used visual art as a means of boosting up the morale of civilians and British soldiers on the Front. The War Artists‟ Scheme brought into being under the auspices of the Propaganda Department in 1914 allowed some of the most promising British artists to produce memorable paintings. The works documented the numerous sites of the Western and Eastern Front. In addition, the artists employed under the scheme presented the nation with portraits of notable military and political figures engaged in the war effort. This thesis investigates how William Orpen, an established society portraitist and A.R.A., fits into the War Artists‟ Scheme. His position was problematic: as a painter working in an early twentieth-century descriptive vein and older than other artists at the Front, how did he fare in this troubled context? Orpen‟s work on the Western Front (France and Flanders) has been so far neglected and considered to be of little relevance in comparison to what other avant-garde artists produced during the same time span. The thesis investigates how Orpen, although painting in an early twentieth-century representational style considered slightly passé, embedded in his works innovative means of expression, creating vivid, haunting imagery, adding to a body of work which was supposed to be documentary a depth reminiscent of ecclesiastic artistic practice. The thesis attempts to re-evaluate Orpen‟s war oeuvre, an aspect of the artist‟s rich imagery hitherto left to oblivion.
207

Study of 2,5-Diaminoimidazolone, a Mutagenic Product of Oxidation of Guanine in DNA

Pollard, Hannah Catherine J 01 December 2017 (has links)
2,5-diaminoimidazolone (Iz) is an important product of a 4-electron oxidation of guanine. The present research focuses on the mechanisms of formation of Iz via pathways initiated by guanine oxidation by one-electron oxidants (OEOs) generated by X-ray radiolysis in aqueous solutions. The kinetics of formation and yields of Iz in reactions of native highly polymerized DNA with different OEOs have been compared using an HPLC-based quantitative analysis of low-molecular products generated from the reaction of DNA-bound Iz with primary amines. Mechanisms of Iz formation in DNA have been investigated including oxygen and superoxide dependence as well as the hypothesis that 8-oxo-G, another product of guanine oxidation, is not a major precursor to Iz. Results indicate Iz is produced in significant quantities in DNA from guanine oxidation and the efficiency of its formation correlates with the reduction potential and selectivity of a given OEO.
208

The One Man Crew: The Creating and Sustaining of a Master Folk Artist

Williams, Heidi Jean 01 May 2014 (has links)
Folk art is the art of everyday life. Framing homes can be artistic when done with a degree of exemplary expertise. Jerry Saville is a master folk artist because of his special skills and techniques exhibited in his trade of carpentry. This research provides a glimpse into a carpenter’s life to discover what creates and sustains a master carpenter. Through desire, drive, dedication (time/practice), life experience/opportunity (apprenticeship), purpose, and a community of support, Jerry Saville became a master folk artist.
209

Transitioning from Student to Nurse Practitioner Using the One-Minute-Preceptor Model

Seymour, Yetrevias 01 January 2019 (has links)
Nurse practitioners (NPs) are significant members of the health care team. Variation and lack of standardization in the practicum preparation of the NP has been identified as problematic. There is a need to improve NPs preparation to efficiently and independently impact health care. This project presented the 1-minute-preceptor (OMP) model as a standard tool in the practicum preparation of the NP through a preceptor-focused continuing education session. The aim of the OMP is to help ensure that students are exposed to the level of critical thinking and problem solving needed in the role of an independent, efficient NP. Knowles's adult learning theory and the educational design process model provided the theoretical framework and guided the development, implementation, and evaluation of the continuing education program. Participation in the continuing education program was voluntary. Pretests, posttests, and evaluations of the continuing education session were collected and analyzed. Ten preceptors participated in the educational session and evaluation. Based on pretest and posttest results, knowledge of the OMP model improved from 70% before the education program to 100% after the program. Participants also indicated interest in using a tool capable of ensuring an effective student-preceptor encounter, and 100% stated they would use the information presented in future preceptor–student interactions. Continuing education program evaluation results indicated participant satisfaction with the presentation. To positively impact social change, the findings of this project may be used by NPs and preceptors to effectively and efficiently impact patient outcomes early in practice.
210

Maximal Rank-One Spaces of Matrices Over Chain Semirings

Scully, Daniel Joseph 01 May 1988 (has links)
Vectors and matrices over the Boolean (0,1) semiring have been studied extensively along with their applications to graph theory. The Boolean (0,1) semiring has been generalized to a class of semirings called chain semirings. This class includes the fuzzy interval. Vectors and matrices over chain semirings are examined. Rank-1 sets of vectors are defined and characterized. These rank-1 sets of vectors are then used to construct spaces of matrices (rank-1 spaces) with the property that all nonzero matrices in the space have semiring rank equal to 1. Finally, three classes of maximal (relative to containment) rank-1 spaces are identified.

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