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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.
21

The Flinders current and upwelling in submarine canyons

Arthur, William Craig, School of Mathematics, UNSW January 2006 (has links)
The continental shelf off South Australia is incised by some of the largest known submarine canyons. Extensive observations of submarine canyons in other parts of the world have shown submarine canyons can result in locally persistent upwelling regions. Along the southern coastline, westward slope currents including anticyclonic eddies and the Flinders Current (FC) can result in favourable conditions for upwelling in the vicinity of these canyons. Little data is available to describe the FC and so we review three global ocean circulation models and their representation of the FC. Though there are considerable differences between the outputs of these three models, this analysis provides a range of potential scales for the structure and transport of the FC. The reasons for the differences between the output of the three models are extensive, but to a first approximation, climatological surface wind stress products are compared. Dynamical descriptions of the flow past submarine canyons are reviewed and in part extended, in particular the vertical scale of the induced motion is estimated as the Rossby height RH. A description of upwelling and downwelling flow incorporating vorticity stretching is also presented. An idealised model of the southern Australian continental shelf and the submarine canyons reveals the circulation is heavily modified by the presence of the canyons, inducing persistent upwelling of dense water onto the downstream shelf. In addition, one prominent feature of the induced circulation ??? a coastal jet ??? is found to be peculiar to flat inner shelf topographies. More realistic topography including a sloped inner shelf results in reduced shoreward transport within the canyon and hence reduced upwelling.
22

Living free radical and photo initiation studies of acrylate, methacrylate and itaconate polymerization systems

Szablan, Zachary Peter, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2008 (has links)
This thesis work has focused on the study of itaconate monomers and photo-initiation processes in acrylate, methacrylate and itaconate monomer systems. Novel information pertaining to photo-initiator derived radical species and their reactivity, as well as the behaviour of itaconate polymerization systems is presented in detail. The knowledge gained from the photo-initiation studies is utilized as a precursor to mark polymer chains using nitrones as radical spin traps and the applicability of this technique discussed. The sterically hindered monomers dimethyl itaconate (DMI), di-n-butyl itaconate (DBI) and dicyclohexyl itaconate (DCHI) were polymerized via reversible addition fragmentation chain transfer (RAFT) free radical polymerization. The RAFT mediated polymerization of these monomers displayed hybrid living behaviour (a mix of conventional and living free radical polymerization characteristics) of varying degrees depending on the molecular structure of the RAFT agent employed. DCHI was also polymerized using atom transfer radical polymerization (ATRP). The resulting molecular weight distributions are broad for the RAFT mediated systems (1.2 ≤ PDI ≤ 3.4). The molecular weight distributions generated via the ATRP of DCHI are narrower (1.2 ≤ PDI ≤ 1.5). Chain transfer to monomer constants for the itaconate monomers DMI, DBI and DCHI have been determined at 60 ??C (CDMI = 1.4⋅10-3, CDBI = 1.3⋅10-3 and CDCHI = 1.0⋅10-3) and are relatively large in comparison to similar 1,1-disubstituted systems, suggesting that the transfer to monomer reaction is significant. PREDICI?? simulations confirm that a significant chain transfer to monomer step results in broad molecular weight distributions. Viscosity of the polymerizing system has also been shown to be an important factor in the resulting width of the molecular weight distributions. Chain extension of RAFT capped pDCHI and pDBI yield molecular weight distributions that progressively shift to higher molecular weights. Thermogravimetric analysis (TGA) of pDCHI-block-pStyrene copolymers indicates thermal degradation in two separate steps for the pDCHI and pStyrene blocks. Conventional pulsed laser polymerization coupled with size exclusion chromatography (PLP-SEC) as well as multi-pulse pulsed laser polymerization (MP-PLP) has been employed to study the depropagation kinetics of DMI, DBI DCHI and di(4-tert butylcyclohexyl) itaconate (DBCHI). The effective rate coefficient of propagation, kp eff, was determined for DMI, DBI and DCHI in bulk and solution of cyclohexanone (DCHI), N-methylformamide (DMI and DBI) and anisole (DBCHI) for monomer concentrations between 0.7 &lt cM 0 &lt 7.1 mol L-1 in a wide temperature range (0 &lt T &lt 90 ??C). The resulting Arrhenius plots (i.e. ln kp eff vs. 1/RT) displayed a significant curvature in the higher temperature regimes and were analyzed in their respective linear and curved sections to yield the activation parameters of the forward and reverse reaction. Mark-Houwink-Kahn Sakurada parameters for pDBI and pDBCHI were determined in tetrahydrofuran at 40 ??C using triple detection gel permeatation chromatography. High resolution Electrospray Ionization - Quadrupole Ion Trap Mass Spectrometry (ESIMS) was applied to study the polymeric product spectrum generated by the pulsed laser polymerization (PLP) of methyl methacrylate (MMA), methyl acrylate (MA), butyl acrylate (BA) and DMI at temperatures ≤ 0 ??C in the presence of various photo-initiators including 2,2-dimethoxy-2-phenylacetophenone (DMPA), benzoin, benzil, benzoin ethyl ether (BEE) 2,2-azobisisobutyronitrile (AIBN) and bis(2,4,6-trimethyl-benzoyl)- phenylphosphinoxide (Irgacure 819) to study the reactivity of primary and potential secondary derived radical fragments from photolytically induced fragmentation. Termination products, both combination and disproportionation, were identified with high accuracy. Results have been compiled in a user friendly table presenting the reactivity of the various photolysis product fragments towards the different monomers. Energy deposition into the MA/photo-initiator systems is found to have no influence on the product distributions of the MA polymers produced via photo-initiation under the conditions examined. For various photo-initiators employed, products congruent to that of chain transfer to monomer species in the DMI photo-polymerizations are observed, conclusively illustrating that chain transfer to monomer is a significant reaction pathway in itaconate free radical polymerizations. Both the benzoyl and acetal fragments generated as a result of DMPA photo cleavage were found to initiate and highly likely terminate polymerization. Under the conditions studied, the acetal radical produced upon DMPA photolysis fragment further to yield methyl radicals which seem to act predominantly as terminating moieties. Both the benzoyl and ether fragments produced as a result of benzoin photo cleavage were found to act as initiating and probable terminating species, indicating that the ether radical fragment does not act exclusively as a terminating species. Additionally, increasing laser intensity and/or irradiation repetition rate (i.e., energy deposition into the system) results in more complex product distributions of the MMA polymers produced via photo-initiation (with the exception of AIBN). Temperature was determined to have a minor influence on the resulting product distribution under the conditions examined. Polymerization systems utilizing Irgacure 819 give complex product spectra due to the formation of second generation radical species resulting in several initiator fragments incorporated into a single polymer chain. A novel method utilizing PLP in free radical polymerization has been developed for marking of polymer chains with radical spin traps. By introducing a so-called “marker” (nitroxide derived from a nitrone), which specifically terminates propagating radicals via combination, a polymer subdistribution is generated which can be measured by ESI-MS and may potentially be utilized to determine propagation rate coefficients of ultimate accuracy. The general methodology of the technique in which such marker radicals are generated via reaction of an initiating radical with a nitrone is demonstrated on the examples of butyl acrylate (BA) and vinyl acetate (VAc).
23

Investigating the key determinants in up-scaling undifferentiated growth of human embryonic stem cells in bioreactor systems

Prowse, Andrew Benjamin James, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2008 (has links)
Human Embryonic Stem (hES) cells will potentially have important applications in regenerative medicine, drug discovery and therapeutics. However, the current methods of hES cell culture limit their use in future applications due mostly to the inability to culture undifferentiated hES cells in sufficient numbers and the concern of animal derived products used in culture methods potentially implementing an immune rejection in transplantiation recipients. This project investigated two approaches for improving the culture of undifferentiated hES cells for future application in bioreactor systems. Firstly, proteins from the conditioned medium of three hES cell supportive fibroblast lines (human fetal, human neonatal and mouse embryonic fibroblasts) were identified using two-dimensional liquid chromatography, tandem mass spectrometry. This proteomic analysis identified 175 unique proteins including those from key pathways already implicated in the maintenance of human embryonic stem cell pluripotency including the Wnt, BMP/TGF-β1, activin/inhibin and insulin like growth factor-1 pathways. Identification of proteins in fibroblast conditioned medium will aid the development of a defined medium for undifferentiated hES cell culture. The second approach examined culture of hES cells in hypoxic conditions (5% O2) compared to standard normoxic conditions in CO2 incubators (20% O2). Feeder layer and feeder free culture conditions were examined in the two O2 concentrations. hES cell colonies grown in hypoxic culture had improved percentages of pluripotent cells (judged by increases in cells expressing SSEA-4, Tra-1-60 and nanog and reduction of BMP-4), stable karyotypes and increased proliferation. The maintenance of pluripotency, apoptosis and proliferation was complicated by the detection of the cell surface marker CD30. Proteomic identification and investigation into oxidative stress indicated the presence of antioxidant enzymes such as superoxide dismutases, catalases and peroxiredoxins in human fetal fibroblast conditioned medium and their regulation of redox homeostasis may play a significant role in the maintenance of hES cell pluripotency, apoptosis and proliferation. Together these investigations significantly contribute to the current body of knowledge for the undifferentiated culture of hES cells. Identification of conditioned medium proteins and the benefits of hypoxic culture of hES cells will aid the development of a defined, reproducible method of hES cell scale-up in bioreactor systems.
24

Selective detection in an iterative soft interference cancellation receiver

Sun, Kyung Tae (John), Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2006 (has links)
This thesis proposes an idea to selectively detect the code bits in an iterative soft interference cancellation multiuser receiver. It is of a great interest to reduce the complexity of the multiuser detectors in order to achieve faster multiuser communication systems. Although the suboptimum detector has much less complexity than the optimum, the detections are made on each code bit of all users through-out every iteration. Selective detection greatly reduces the amount of calculation by re-detecting only the unreliably detected code bits from the second iteration. Simulation results show that the number of detections is significantly reduced, while the performance is maintained. Necessary background information to understand the working principles of the iterative soft cancellation receiver is presented as well. Selective detection may also be used in any other receiver structures with iterative procedures to provide much less complexity. Hence, it is able to handle much more complicated receiver structures, or implement the system to a mobile device where the computational ability is much less than at the base station.
25

Sustainability and the struggle for hegemony in Australian architectural education.

Graham, Peter M., School of Architecture, UNSW January 2008 (has links)
This study is situated within the contested fields of architectural education and sustainable development. It seeks to identify ideological positions within discourses related to these fields in order to explain documented resistance to the integration of sustainable design curricula in architectural education. To understand resistance to such integration we must go beyond identifying the problem. To affect curriculum change it is necessary not only to have a design for a desired state, but also to gain the power to implement it. This assumption demands both an understanding of the power relations that support the status quo and an acceptance of curriculum development as a process of ideological struggle. Hence, efforts to reform architectural education need to be informed by an understanding of the hegemonic struggles which shape architectural curricula. Existing research in the field of sustainable design education has not focussed on such issues. International studies have not considered curricula as manifestations of a history of ideological struggle. Nor have detailed studies of sustainable design education in schools of architecture been conducted in Australia. This study has addressed these knowledge gaps by investigating histories of ideas in architectural and sustainability education. A critical discourse analysis was conducted of the handbook descriptions of architectural courses in Sydney over the last thirty years, and of courses offered in 2007 by all Australian schools of architecture. This analysis was supported by curriculum mapping to reveal the power relations inherent in architectural curricula. The research has identified strategies of hegemonic struggle which affect the hegemony of ideologies in Australian architectural education and the positioning of sustainable design curricula within this contested field. I have found that sustainable design curricula are marginalised in Australian architecture courses and that this marginalisation has been historically constructed. I have also exposed hegemonic strategies that reproduce such marginalisation within curricula.
26

Origins and destinations: representation in the theatre of Romeo Castellucci

Lyandvert, Max, School of Theatre, Film & Media, UNSW January 2006 (has links)
This thesis: Origins and Destinations: Representation in the theatre of Romeo Castellucci, investigates the working methodology of the Italian theatre director, Romeo Castellucci and his company, Societas Raffaello Sanzio. It provides an account of Societas Raffaello Sanzio???s history, working methods, a detailed reading of the thematic and philosophical landscape in their works especially Genesi: from the museum of sleep, and the cycle: Tragedia Endogonidia, and a discussion on the company???s artistic process towards the formation of its compositions and performances. This research and investigation is based on numerous viewings of most of the company???s theatre works created in the last six years, interviews with Romeo Castellucci as well as other participating artists, two privileged periods of observation (residencies) in Italy of the rehearsal and creation processes of three shows, and the analysis and discussion of some of the key critical and intellectual responses to the work of Romeo Castellucci. The thematic focus of the thesis is the notion of Origins and Destinations, and its relationship with the language of representation in Romeo Castellucci???s theatre. The theoretical discussion in the thesis is organised around Giorgio Agamben???s notion of Potentiality within the composition and content of Castellucci???s theatre. This concept provides a link between the key ideas of Origins, Destinations and Representation. Castellucci???s application of Agamben???s Potentiality deconstructs dramatic structure, narrative and action down to the fundamentals of the act itself, separated from its meaningful context. It is the conclusion of this thesis, that in the instant of this singular act, Romeo Castellucci manages to represent a point where origin and destination meet, or a point where they both are, for an instant, one and the same thing.
27

Being and doing ???Bengali-Muslims??? in Sydney: the construction of Halal and Haram.

Mahmood, Raasheed, School of Sociology & Anthropology, UNSW January 2006 (has links)
This is a study against essentialist generalisations. Empirically, the study has been conducted to understand the food related practices among the Bengali-Muslim migrants in Sydney based on the dichotomy of Halal (permitted in Islam) and Haram (prohibited in Islam). Instead of evaluating Islam and Muslim communities as monolithic and undifferentiated this study reveals the localised actualisation of Islam which serves as a conditioning factor for these Bengali-Muslim migrants. Adopting a naturalistic methodological approach a number of ethnographic tools have been used to reveal the complex multifaceted processes through which Sydney???s Bengali-Muslim migrants negotiate the situational convergence and divergence between their ethnic identity as Bengali and their religious identity as Muslim. As a significant site of this interplay this study discovers from their food related practices that the Bengali-Muslim migrants in Sydney construct the notion of Halal-Haram food rules and regulations through the dialectics of their Bengali-informed Islam. The Bengali version of Islam poses considerable challenge to the modernist opposition between secularism and religion which is quite inadequate to understand the way the Bengali-Muslims historically negotiate both of these in the form of overlapping consensus. The findings of the study exhibit that this situationally shifting emphasis on their secular Bengali identity at one point of time and on their religious Muslim identity at another determines their decisive practices regarding food consumption in a Western cultural milieu. The Bengali-Muslim migrant participants of this study tend to perceive the notion of Halal-Haram in multiple ways so as to fit the pragmatic realities of their migrant life, which eventually leads them to reconstruct, renegotiate or even discard the scriptural/theological/authoritative discourse. Such underlying properties of food practices vindicate the argument that any stereotypically standardised notion of ???Islam??? is inadequate to understand varied Muslim migrant communities across the globe. Rather specific Muslim migrant community should be studied along with a profound understanding of their very contextual nature and historical formations.
28

Second skin: exploring perceptions of contemporaryknitting.

Clifton-Cunningham, Alana, Design Studies, College of Fine Arts, UNSW January 2008 (has links)
Using written and studio research, the above research question is interrogated through a body of practical work, that evolved into a static exhibition titled Second skin: new knitting at The Ivan Dougherty Gallery, Paddington, New South Wales, Australia, in January/February 2008. This thesis examines knitting as a form of constructed textile in an historical and contemporary context and explores the integral relationship it has with fashion and textiles, as well as questioning the significance of interplay between fashion and art. The primary aim of this research is to explore contemporary knitwear designers working in the high-fashion’ area of design and investigate how they are challenging traditionally established rules and perceptions, and potentially blur the boundaries of what is considered fashion design, into art. While conceptual fashion design has always been a debateable issue among fashion scholars as to whether it can be viewed as fashion, antifashion or possibly art, this thesis examines the influences of modernity and deconstruction in relation to knitting, to establish a conclusion regarding the contemporary position and understanding of knitting in society at present. Through gathering both primary and secondary research nationally and internationally, knitting has been examined in relation to the ways in which contemporary designers working in the realm of knitting are unravelling these traditionally based preconceptions, and analysing what they are accomplishing through the use of mixed media applications, post-knitting treatments, yarn and stitch manipulation, and challenging sculptural form to create a new visual language through artisanal production. The body of work presented explores the concepts established in the written research relative to perception and deconstruction, and provokes questions which challenge the notion of knitting as fashion, art or both. Through hand and machine knitting techniques, Second skin: new knitting examines body scarification in the form of tribal markings, which allows each pieces to transform into a second skin that convey interpretive narratives and visual messages. The predominant medium utilised is 100% Australian wool and in conjunction, incorporates mixed media materials such as silk organza and semi precious stones, and technological processes include laser cutting and etching of Tasmanian oak veneer and leather.
29

I came, I saw, I ???? Contemporary Australian representations that return the tourist gaze

Vogler, Agnes, School of English, UNSW January 2005 (has links)
This thesis adopts post-colonial theory as a reading strategy to address both fiction and interdisciplinary critical writing on the subject of tourism. The introduction argues for the viability of this methodology, highlighting similarities between the ideological underpinnings of tourism and imperialism, especially in relation to the power of the gaze. The first chapter draws on analyses of early exploration and travel writing to advance the argument that as the ideology of empire was encoded in travel writing, so contemporary tourist culture, in so far as it has inherited this discourse, continues to operate within it. I suggest that in much the same way as the explorer???s gaze was a form of creating knowledge disseminated through writing, fiction constitutes a cultural production that contests the power of the gaze. The second chapter focuses on the ambivalent effects of the commodification of culture caused by the tourist industry. I argue that cultural tourism, centred on heritage and history, has constituted a platform from which to review conventional representations of Australian history in a way that demonstrates the relevance of heritage to contemporary national narratives. The third and final chapter examines the relationship between cultural performances in tourism and subject formation, contending that the repetitive nature of performance offers an ideal opportunity to interpolate transformative views of both locals and tourists into the conventional tourist discourse.
30

Computational model of epirentinal stimulation

Cheng, Jia, Graduate School of Biomedical Engineering, Faculty of Engineering, UNSW January 2005 (has links)
The quality of visual perception with epiretinal electric stimulation strongly depends on the configuration of electrode arrays. Such arrays at the surface of the retina should excite only cells within a local area, but in practice, they exhibit some cross-talk, possibly leading to a smearing of focal activation of the retina. In this study, a passive model of extracellular voltage distribution arising from epiretinal stimulation is solved using the method of finite differences, in order to explore the voltage and current distributions of a hexagonal electrode array configuration. Results of this study suggest that the hexagonal electrode arrangement is effective in providing targeted focal activation of retinal tissue. Cross-talk between hexagonal clusters may be minimized by stimulus paradigms which utilize six return (or guard) electrodes around each stimulus electrode.

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