This thesis investigated the effects of intergroup contact on different types of collective action tendencies among advantaged and disadvantaged groups. Studies 1 and 2 tested the simultaneous effects of intergroup contact and established predictors of collective action on collective action tendencies and ingroup and outgroup oriented policies among Blacks and Whites in South Africa, and compared the effects of intergroup contact and social identity on collective action tendencies via relative deprivation and group efficacy. The findings revealed that while social identity was positively associated with collective action tendencies, both directly and indirectly, effects of contact were negative and indirect via relative deprivation and group efficacy. Studies 3 and 4 investigated the effects of contact and social identity on collective action tendencies via perceived threats. Using data from Turkish and Kurdish groups in Turkey, I found that social identity predicted collective action tendencies positively, both directly and indirectly, while it predicted outgroup attitudes negatively and indirectly via perceived threats. Intergroup contact, on the other hand, predicted outgroup attitudes positively, both directly and indirectly, and collective action tendencies negatively via perceived threats. In Study 5, intergroup contact was positively associated, both directly and indirectly, via perspective taking and collective guilt, associated with outgroup oriented collective action tendencies. In Study 6, the effect of social identity on ingroup oriented collective action was positive and direct. Intergroup contact with the weaker minority group, on the other hand, was positively associated with outgroup oriented collective action tendencies via perspective taking. Additionally, intergroup contact with the majority outgroup moderated this relationship. When participants reported more contact with the majority group, intergroup contact with the weaker minority was not associated with outgroup oriented collective action tendencies. However, when the participants reported less contact with the majority group, intergroup contact positively predicted outgroup oriented collective action tendencies. Finally, Study 7 investigated the effects of two different dimensions of contact, contact with the majority and minority on collective action, via outgroup attitudes, dual-identification, and common ingroup identity in a three wave longitudinal design (N=610) among Turkish Cypriots in northern Cyprus. While the results did not support findings from the previous studies on the so-called paradoxical effects of contact on collective action tendencies, they revealed a robust negative reciprocal relationship between outgroup attitudes toward Greek Cypriots and collective action tendencies.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This artistic research dissertation employs the principles and practices of contact improvisation in a literary performative to describe and demonstrate this somatic form’s potential as a complex system of embodied knowing. For strategic and thematic purposes, chapters in this dissertation are referred to as Streams. The First Stream motivates the methodological approaches and emergent strategies employed in the researcher’s simultaneous practices of teaching, researching and writing about contact improvisation. The Second Stream is offered as an oral testimony of the researcher’s attempt to find practical solutions for the increasing complexity apparent in her work environment during the last two decades. It is written primarily as a first-person narrative with references by other somatic and contact improvisation practitioners embedded in the body of the narrative and presented as personal subconscious/collective unconscious interjections. The Third Stream uses a locally-emergent artistic research strategy termed Secondary Primacy to critically and creatively engage with existing literature. The observations of theorists and practitioners from the researcher’s own context (theatre and drama), as well as from a diversity of interrelated disciplines (including psychology, sociology, evolutionary biology, quantum physics, pedagogy and visual art) are presented in an autonomous authorial voice employing the performative strategy of what if. This strategy serves to demonstrate the researcher’s experience of the link between personal subconscious and collective unconscious motivations for action and exposes the transdisciplinary ground upon which many of the ideas and observations voiced in other Streams, in particular about contact improvisation as a complex system of embodied knowing, are implicitly dependent. The Fourth Stream discusses contact improvisation as a complex system foregrounding the particular characteristics of nonlinearity, paradox, emergence and additional capacity introduced in the Second and Third Streams. The Fifth Stream demonstrates convergences and overlaps between contemporary theories about agency, embodiment and transformation as they may apply to educators in tertiary educational performing arts contexts. This discussion is interspersed with accounts of the researcher’s own attempts – through her performing arts educational practice - to understand agency and transformation as workable elements. The Sixth Stream is offered as a personal philosophy of action. The implicit values and strategies of the researcher that were exposed in previous Streams are here distilled and presented as affirmations and Actions motivating the sustained use, by the researcher within her localized educational context, of contact improvisation as a foundational somatic approach for performers. In keeping with the positioning of this dissertation as artistic research, the literary framing devices of a Foreword and Afterword are used to draw a reader’s attention to the practicebased nature of the subject under discussion. / AFRIKAANSE OPSOMMING: Hierdie artistieke navorsingsverhandeling gebruik die beginsels en praktyke van kontakimprovisasie in ‘n literêre performatief om hierdie somatiese vorm se potensiaal as ‘n komplekse sisteem van verpersoonlikte kundigheid te beskryf en te demonstreer. Vir strategiese en tematiese doeleindes word daar in hierdie verhandeling na hoofstukke as Strome verwys. Die Eerste Stroom motiveer die metodologiese benaderinge en voortspruitende strategieë wat aangewend word in die navorser se gelyktydige onderrig van, en navorsing en skrywe oor, kontakimprovisasie. Die Tweede Stroom word aangebied as ‘n mondelinge betuiging van die navorser se poging om praktiese oplossings te vind vir die toenemende kompleksiteit in haar omgewing oor die laaste twee dekades. Hierdie Stroom word primêr as ‘n eerste persoon narratief aangebied met behulp van verwysings deur ander somatiese en kontakimprovisasie praktisyns wat in die narratief geanker en aangebied word as persoonlike onbewustelike/kollektiewe onbewuste tussenwerpsels. In die Derde Stroom word ‘n plaaslik ontwikkelde artistieke navorsingstrategie, naamlik Sekondêre Voorrang, gebruik om die konvensionele literatuurstudie op kreatiewe wyse te herinterpreteer. Die waarnemings van teoretici en praktisyns uit die navorsers se eie studieveld (teater en drama), sowel as uit ‘n verskeidenheid van interafhanklike studievelde (onder andere psigologie, sosiologie, evolusionêre biologie, kwantum fisika, pedagogie en visuele kuns) word aangebied as ‘n outonome outeursbedoelde stem en maak gebruik van ‘n performatiewe what if. Díe strategie dien as ‘n metode om die navorsers se ervaring van die implisiete afhanklikhied tussen persoonlike onderbewussyn en kollektiewe onbewustheid motiverings vir aksie te demonstreer, en die transdisiplinêre grond van idees en waarnemings, in die besonder oor kontakimprovisasie as ‘n komplekse sisteem van verpersoonlikte kennis, te ontgin en bloot te lê. In die Vierde Stroom word kontakimprovisasie as ‘n komplekse sisteem bespreek en die eienskappe van nie-liniariteit, paradoks, ontluiking en addisionele kapasiteit wat in die Tweede en Derde Strome bespreek is, is verder op die voorgrond geplaas. Die Vyfde Stroom toon die sameloop en ooreenkomste aan tussen teorieë oor tussenkoms, verpersoonliking en transformasie soos van toepassing mag wees op opvoeders in ‘n tersiêre opvoedkundige performance konteks. Hierdie bespreking is afgewissel met vertellings van die navorser se eie pogings - deur haar uitvoerende kunste opvoedkundige praktyk – om agentskap en transformasie as werkbare elemente te verstaan. Die Sesde Stroom word aangebied as ‘n persoonlike filosofie van handeling. Die implisiete waardes en strategieë van die navorser, soos bloot gelê in die vorige Strome, word hier gesuiwer en aangebied as bekragtiging en Aksies vir die volgehoue gebruik, deur die navorser in haar eie gelokaliseerde opvoedkundige konteks, van kontakimprovisasie as ‘n grondleggende somatieke benadering vir performers. As deel van hierdie verhandeling se posisionering as artistieke navorsing word ‘n Voorwoord en Slotwoord gebruik om die leser se aandag te vestig op die verpersoonlikte aard van die onderwerp onder bespreking.

The continued miniaturization and proliferation of electronics is met with significant thermal management challenges. Decreased size, increased power densities, and diverse operating environments challenge the limitations of conventional thermal management schemes and materials. To enable the continuation of these trends thermal interface materials (TIMs) that are used to enhance heat conduction and provide stress relief between adjacent layers in a electronic package must be improved. Forests comprised of nominally vertically aligned carbon nanotubes (CNTs), having outstanding thermal and mechanical properties, are excellent candidates for next-generation thermal interface materials (TIMs). However, despite nearly a decade of research, TIMs based on vertically aligned CNT forests have yet to harness effectively the high thermal conductivity of individual CNTs. One of the key obstacles that has limited the performance of CNT TIMs is the presence of high thermal contact resistances between the CNT free ends and the surfaces comprising the interface. The aim of this research is to better understand the mechanisms by which the thermal contact resistance of CNT forest thermal interfaces can be reduced and to use this understanding towards the design of effective and to scalable processing methods. Contact area and weak bonding between the CNT tips and opposing surface are identified as factors that contribute significantly to the thermal contact resistance. Three strategies are explored that utilize these mechanisms as instruments for reducing the contact resistance; i) liquid softening, ii) bonding with surface modifiers, and iii) bonding with nanoscale polymer coatings. All three strategies are found to reduce the thermal contact resistance at the CNT forest tips to below 1 mm2-K/W, a value to where it is no longer the factor limiting heat conduction in CNT forest TIMs. These strategies are also relatively low-cost and amenable to scaling for production when compared to existing metal-based bonding strategies.

published_or_final_version / Language Studies / Master / Master of Arts

<p>The purpose of this thesis was to study the influence of manufacturing variations on gear performance. The manufacturing variations inherent in different manufacturing methods were studied to include the effect of real surfaces. Real surfaces have surface irregularities at least on some scale, which can significantly influence how loads are transmitted at the gear contact. To some extent, the lubricant design can help to prevent contact that could lead to tooth failures by forming a protective surface boundary layer. An experimental study was used to consider the compositions of these layers with a surface analysis method.</p><p>In Paper <strong>A</strong> a robust design approach was used to find out to what extent the current standard for calculation of surface durability treats manufacturing variations and the choice of lubricant. The results show that the simplest calculation method used is not enough to predict the effect of these on surface durability. Additionally, the standard quality levels are poorly incorporated in the standard calculating procedures for surface durability, and the quality of the gear tooth is restricted to include only a few parameters.</p><p>In Paper <strong>B</strong> a pin-on-disc machine was used to evaluate the tribofilm formation by the additives and the corresponding wear occurring in the boundary lubrication regime in environmentally adapted lubricants. Studies of the additive and base fluid interaction were carried out using glow discharge-optical emission spectroscopy. It was found that the chemically reacted surface boundary layers played an important role in terms of wear. More specifically, the oxide layer thickness had significant influence on wear. The findings also demonstrate the complexity of lubrication design formulations coupled to these layers. For example, it was found that the pre-existing surface boundary layer (before any lubricant had been added) played an important role in allowing the lubricant to react properly with the surfaces.</p><p>The aim of Paper <strong>C</strong> was to contribute to the knowledge of how different surface topographies, tied to manufacturing methods, influence the early life contact conditions in gears. Topographical measurements of differently manufactured tooth flanks were used as data input to a contact analysis program. The variation in surface topography inherent in the manufacturing method was found to have a strong influence on the contact area ratio.</p>

<p><strong>Syfte: </strong>Syftet med studien var att ta reda på hur stor skillnad det gör för medelvärdet på det slutgiltiga intraokulära trycket (IOP) då det mäts en, två, tre eller sex gånger med en noncontact tonometer. Syftet var också att komma fram till vilket antal mätningar som borde vara det korrekta.</p><p><strong>Metod: </strong>Alla mätningar utfördes med hjälp av Topcons non-contact tonometer CT-80A. Mätningarna upprepades på båda ögonen till dess att sex korrekta värden hade mätts upp. Högerögat mättes alltid först. Alla försökspersoner i studien hade normala IOP-värden. IOP mättes på både höger och vänster öga på 60 försökspersoner i åldern 18-50 år.</p><p><strong>Resultat</strong>: Studien visar att medelvärdet för IOP sjunker ju fler mätningar som görs. Medelvärdena (± SD) för mätning 1, 1-2, 1-3 och 1-6 är 15,70 ± 2,81 mmHg, 15,37 ± 2,58 mmHg, 15,14 ± 2,41 mmHg respektive 14,78 ± 2,44 mmHg på högerögonen. Motsvarande värden är 14,43 ± 2,25 mmHg, 14,42 ± 2,15 mmHg, 14,38 ± 2,18 mmHg respektive 14,25 ± 2,21 mmHg på vänsterögonen. Skillnaden mellan medelvärdena är statistiskt signifikanta på högerögat men inte på vänsterögat. Det finns en minskning i IOP-värdet mellan första och andra mätningen på 4 mmHg eller mer, på sju högerögon och två vänsterögon. Vid jämförelse mellan ögonen är skillnaden statistiskt signifikant för den första mätningen och medelvärdet för mätning 1-2, men inte för medelvärdena för mätning 1-3 och 1-6. För att skillnaden mellan ögonen ska vara under 4 mmHg hos alla försökspersoner i studien krävs att minst tre mätningar inkluderas i medelvärdet.</p><p><p><strong>Slutsats: </strong>Eftersom det i vissa fall finns en stor sänkning i IOP mellan första och andra mätningen på högerögat, bör minst två mätningar göras i en screeningsituation. Uppmäts då ett IOP som är minst 3 mmHg lägre än gränsen för ett onormalt IOP så räcker det med dessa två. Är IOP närmare gränsen än så bör minst tre mätningar tas för att se om IOPvärdet förändras. Studien visar även att tre mätningar eliminerar de stora skillnader som uppmätts mellan ögonen hos försökspersonerna. Om första mätningen är mycket högre än övriga, eller om ett så korrekt värde som möjligt eftersträvas, så kan fyra mätningar tas och ett medelvärde beräknas på de tre sista.</p></p>

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