Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Entrainment and assimilation of xenolithic material during kimberlite ascent is considered to be important in shaping the chemistry of the magma and fuelling magma ascent by driving CO2 exsolution. Previous, but as yet unpublished experimental work from Stellenbosch University has demonstrated that orthopyroxene has a key role in this. Orthopyroxene is a very rare xenocrystic constituent of kimberlite but makes up a considerable fraction of the entrained xenolithic material. The initial study used a natural kimberlite composition (ADF1) doped with a peridotite mineral suite (by weight); 88 % ADF1 5% olivine, 5% orthopyroxene and 2% garnet-spinel intergrowth as a starting composition. The subsequent high PT experiments (1100 to 1300°C and 2.0 to 3.5GPa) established that equilibrium orthopyroxene is stable at 1100°C above 2.5GPa, at 1200°C above 2.5GPa and at 1300°C between 2.0 and 3.5GPa. At lower pressures orthopyroxene is completely digested by the experimental melt by the reaction; Mg2Si2O6 (opx) = Mg2SiO4 (ol) + SiO2 (in liquid). In contrast, clinopyroxene is a common phase in kimberlite and often occurs as more than one generation of crystals. Xenocrystic clinopyroxene is dominated by diopside compositions. However, rare omphacite is sometimes also inherited from an eclogite source. The Omphacite, like orthopyroxene, displays textural evidence of severe disequilibrium and may also contribute to the evolution of kimberlitic melt. Thus, a second study produced experiments on the ADF1 kimberlite material at upper mantle PT conditions (1100 to 1300°C and 2.0 to 4.0GPa) as well as an omphacite doped starting material (ADF1+O). These experiments examine the behaviour of pyroxene in kimberlite magma including the influence this may have on magma buoyancy. Within this PT range omphacitic clinopyroxene breaks-down via complex multipart reactions. At 1100°C and 2.0GPa reaction textures around remnant omphacite suggest that omphacite melts incongruently in a complex reaction similar to: Omp + Melt = Ap + Cr-diop + SiO2-enriched Melt. At 1300°C omphacite melts completely and is perceived to produce peritectic Cr-diopside, calcium-rich olivine, carbonate in the melt as well as enrich the melt in SiO2. The melts produced by both the ADF1+O and ADF1 compositions at 1300°C and 4.0GPa are reduced in SiO2 content and have increased TiO2, Cr2O3, Al2O3, MnO, CaO, K2O and P2O5 compared to their respective starting compositions. However, significantly higher proportions of Ca, Na and Fe observed within the ADF1+O melt is a direct consequence of omphacite melting. The ADF1+O starting composition produced equilibrium orthopyroxene above 1100°C and 4.0GPa as well as at 1300°C above 2.0GPa. At lower pressure the orthopyroxene melts incongruently to form peritectic olivine and more silica-rich melt compositions. This digestion favours CO2 exsolution. The effect of orthopyroxene melting can be seen in the melt compositions produced by the peridotite doped starting material (ADF1+P) of the initial study. At 1300°C and 2.0GPa, ADF1+P produced a siliceous melt (37.0 wt.% SiO2) enriched in Al and alkalis compared to the starting ADF1+P composition. This behaviour is directly attributed to xenocrystic orthopyroxene melting at high temperature. In contrast, at the same PT the original kimberlite (ADF1) composition produces a melt with 28.9 wt.% SiO2 and high Ca and Mg contents. Overall, with an increase in pressure the melts become enriched in alkalis and Al2O3 as a direct result of xenocrystic pyroxene melting. In addition, increased pressure allows for a greater solubility of CO2 within the melt. This results in a lower SiO2 melt content and the increased stabilization of equilibrium silica-rich mineral phases (i.e. olivine and equilibrium orthopyroxene). Within the peridotite doped static system (unpublished) the mineral separates with an average crystal size of 115μm ±10μm were all effectively digested in less than 48hours. Similarly, the omphacite doped experiments consumed the 150μm (±10μm) xenocrysts in under 24 hours. Thus, it is suggested that xenocrystic pyroxene is unstable in these experimental kimberlitic melt compositions and is likely to be efficiently assimilated in less than 24 hours. These experimental melts most likely resemble those of natural systems under upper mantle PT conditions. Therefore, pyroxene melting increases the silica content of the melt which in turn drives CO2 exsolution and ascent. / AFRIKAANSE OPSOMMING: Meevoering en assimilasie van xenolitiese materiaal gedurenende kimberliet bestyging is beskou as belangrik in verband met die vorming van die chemie van die magma, en bevorder magma bestyging deur die aandrywing van CO2 ontmenging. Vorige, maar ongepubliseerde eksperimentele werk vanaf Stellenbosch Universiteit het gedemonstreer dat ortopirokseen ‘n sleutelrol hierin het, omrede ortopirokseen ‘n baie skaars xenokristiese bestanddeel van kimberliet is maar ‘n aansienlike fraksie van die meevoerde xenolitiese materiaal moet opmaak. Hierdie studie het ‘n natuurlike primere kimberliet komposisie (ADFI) gedoop met ‘n peridotiet mineraal reeks (per gewig); 88 % ADF1 5% olivien, 5% ortopirokseen en 2% granaat-spinel ingroeiing as begin komposisie gebruik. Die daaropvolgende hoë DT eksperimente (1100 tot 1300°C en 2.0 tot 3.5GPa) het vasgestel dat ewewigsortopirokseen stabiel is teen 1100°C bo 2.5GPa, 1200°C bo 2.5GPa en teen 1300°C vanaf 2.0 tot 3.5Gpa. Teen laer druk word ortopirokseen geheel verteer deur die eksperimentele smelting volgens die reaksie Mg2Si2O6 (opx) = Mg2SiO4 (ol) + SiO2 (in vloeistof). In kontras hiermee is clinopirokseen algemeen in kiemberliet en kom dikwels voor as meer as een generasie se kristalle. Diopsiet komposisies domineer xenokristiese klinopirokseen. Seldsame omfasiet is tog somtyds ook geërf vanaf ‘n eklogiet bron. Die omfasiet, soos ortopirokseen, vertoon teksturuele bewys van ernstige disekwilibrium en mag ook bydra tot die evolusie van kimberlitiese smelt. Dus was daar addisionele eksperimente uitgevoer op die ADF1 kimberliet material teen hoër mantel DT kondisies (1100 tot 1300°C en 2.0 tot 4.0GPa), asook ‘n begin materiaal gedoop met omfasiet (ADF1+O). Hierdie eksperimente ondersoek die gedrag van pirokseen in kiemberliet magma, asook die invloed wat dit sal hê op die dryfvermoë van die magma. Binne hierdie DT reeks breek omfasitiese klinopirokseen af via komplekse multideel reaksie prosesse. Teen 1100°C en 2.0Gpa stel reaksie teksture rondom die oorblywende omfasiet voor dat omfasiet ongelykvormig smelt deur ‘n komplekse reaksie soortgelyk aan: Omp + Smelt = Ap + Cr-diop + SiO2-verrykde Smelt. Teen 1300°C smelt omfasiet volkome en is waargeneem om peritektiese Cr-diopsiet, kalsiumryke olivien en kalsiet te produseer, sowel as dat dit die smelt verryk in SiO2. Die smeltings geprodiseer deur die ADF1+O en ADF1 massa komposisies teen 1300°C en 4.0GPa is verlaag in SiO2 inhoud en bevat verhoogde TiO2, Cr2O3, Al2O3, MnO, CaO, K2O en P2O5 in vergelyking met die onderskeie begin komposisies. Aansienlike hoër proporsies van Ca, Na en Fe is egter waargeneem in die ADF1+O smelt en is ‘n direkte gevolg van die smelting van omfasiet. Die ADF1+O begin samestelling het ewewigsortopirokseen bo 1100°C en 4.0Gpa geproduseer en massa teen 1300°C en 2.0 tot 4.0GPa. Teen laer druk smelt hierdie pirokseen inkongruent om peritektiese olivien en meer silika-ryke smelt samestellings te vorm, en ontmeng CO2. Die effek van ortopirokseen smelting kan aanskou word in die smelt samestellings wat produseer is deur die begin materiaal wat gedoop is in peridotiet (ADF1+P), in die oorspronklike studie. Teen 1300°C en 2.0GPa het ADF1+P ‘n silikahoudende smelt (37.0 wt.% SiO2) produseer wat verryk is in Al en alkalies in vergelyking met die ADF1+P massa samestelling. Hierdie gedrag is direk toegeskryf aan die xenokristiese ortopirokseen wat smelt teen hoë temperatuur. In kontras hiermee, teen dieselfde DT kondisies produseer die oorspronklike kiemberliet (ADF1) massa ‘n smelt met 28.86 gewigspersentasie SiO2 en hoë Ca en Mg inhoud. In die algeheel word die smeltings verryk in alkalies en Al2O3 teen verhoogde druk as ‘n derekte gevolg van xenokristiese pirokseen smelting. Verder laat verhoogde druk toe vir hoër oplosbaarheid van CO2 in die smelt, wat lei tot laer SiO2 inhoud en ‘n toename in stabilisering van ewewigs silika-ryke mineraal fases (dws. olivien en ewewigsortopirokseen). In die peridotiet gedoopde statiese sisteem (ongepubliseerd), was die mineraal skeiding met ‘n gemiddelde kristal grootte van 115μm ±10μm almal effektief verteer in minder as 48 ure. Soortgelyk hieraan het die omfasiet gedoopde eksperimente die 150μm (±10μm) sade onder 24 ure verteer. Dus stel dit voor dat xenokristiese pirokseen in naatuurlike sisteme onstabiel is in kiemberlietiese smelt samestellings en sal waarskynlik geassimileer wees in miner as 24 ure en ‘n meer silica-ryke kiemberlietiese smelt samestelling produseer terwyl dit CO2, ontmenging en bestyging aandryf.

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Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The common presence of large volumes of coarse-grained olivine in kimberlite magmas has been proposed to attest to the volume of mantle xenolith material that has been disaggregated during the ascent of the magma. Orthopyroxene should constitute 10-50 vol% of mantle xenoliths in kimberlites, some of which must be disaggregated into the kimberlite, yet it is typically absent. This work tests the stability of orthopyroxene in ascending kimberlite magma by conducting experiments at pressures between 2.0 and 3.5 GPa and temperatures between 1100 and 1300°C. The starting material consisted of natural hypabyssal kimberlite that is close in composition to primary group I kimberlite magma with 5wt% orthopyroxene sourced from a natural peridotite added. At higher temperatures and pressures it is seen that orthopyroxene quantities exceed that of the starting material, but at lower temperatures and pressures it is absent. These results indicate that orthopyroxene is not stable in the magma composition investigated within the shallower part of the sub-continental lithospheric mantle. Based on increased olivine volumes in the experiments where orthopyroxene disappeared, as well as textural relationships between olivine and orthopyroxene, it is found that orthopyroxene dissolution is incongruent along the reaction Mg2Si2O6 (opx) = Mg2SiO4 (ol) + SiO2 (in the liquid). It is concluded that this reaction leads to a maximum addition of 5.5 vol% peritectic olivine to the kimberlite as it ascends through the depths equivalent to a pressure window of 2.0 to 3.5 GPa. / AFRIKAANSE OPSOMMING: The common presence of large volumes of coarse-grained olivine in kimberlite magmas has been proposed to attest to the volume of mantle xenolith material that has been disaggregated during the ascent of the magma. Orthopyroxene should constitute 10-50 vol% of mantle xenoliths in kimberlites, some of which must be disaggregated into the kimberlite, yet it is typically absent. This work tests the stability of orthopyroxene in ascending kimberlite magma by conducting experiments at pressures between 2.0 and 3.5 GPa and temperatures between 1100 and 1300°C. The starting material consisted of natural hypabyssal kimberlite that is close in composition to primary group I kimberlite magma with 5wt% orthopyroxene sourced from a natural peridotite added. At higher temperatures and pressures it is seen that orthopyroxene quantities exceed that of the starting material, but at lower temperatures and pressures it is absent. These results indicate that orthopyroxene is not stable in the magma composition investigated within the shallower part of the sub-continental lithospheric mantle. Based on increased olivine volumes in the experiments where orthopyroxene disappeared, as well as textural relationships between olivine and orthopyroxene, it is found that orthopyroxene dissolution is incongruent along the reaction Mg2Si2O6 (opx) = Mg2SiO4 (ol) + SiO2 (in the liquid). It is concluded that this reaction leads to a maximum addition of 5.5 vol% peritectic olivine to the kimberlite as it ascends through the depths equivalent to a pressure window of 2.0 to 3.5 GPa.

This thesis investigates federalism and civil conflict. Past work linking federalism and civil conflict has investigated the factors that pacify or aggravate conflict, but most such studies have examined the effect of decentralization on conflict onset, as opposed to the form federalism takes (such as congruent vs incongruent forms, for example). I collect data on civil conflict, the institutional characteristics of federalist states and fiscal decentralization. My theoretical expectations are that federations who treat federal subjects differently than others, most commonly in an ethnically based manner, are likely to experience greater levels of conflict incidence and more severe conflict. I find support for these expectations, suggesting more ethnically based federations are a detriment to peace preservation. I close with case studies that outline three different paths federations have taken with regards to their federal subunits.

The kinetics of incongruent reduction between sapphire and oxygen-controlled Mg-Al melts was studied by measuring spinel-layer thickness, sample-weight change and sample-thickness change as a function of time at various temperatures. To eliminate the crucible contamination caused by impurities in commercial MgO crucibles, self-made high-purity MgO crucibles were achieved by gelcasting method, which is an attractive ceramic-forming technique for making high-purity ceramic parts. The oxygen-controlled alloys were obtained by the three-phase-equilibrium experiments at various temperatures. To avoid MgO formation, the oxygen-controlled alloys prepared at relatively lower temperatures were used for incongruent reaction at relatively higher temperatures. That is to say, the oxygen-controlled alloys prepared at 900°C, 1000°C, and 1100°C were used for spinel formation at 1000°C, 1100°C, and 1200°C, respectively. The experiments were conducted in a vertical furnace, and sapphire wafers were hung vertically in high-purity MgO crucibles so that the natural convection induced by the density change in the melt could be investigated. Experimental results obtained at 1000°C, 1100°C, and 1200°C showed that the spinel layer thickness on two kinds of sapphire wafers, namely {0001} and , followed orientation-independent parabolic kinetics, indicating the diffusion in spinel was one of the rate-limiting steps. In addition, the spinel layer thickness was not a function of position. The results of sample-thickness- change measurements also indicated that the effect of natural convection could be neglected. XPS, XRD, and TEM were also employed to characterize some samples in this study. Based on a simple model where the diffusion in spinel was the only rate-limiting step, the governing partial differential equations for diffusion and fluid dynamics were solved by the finite element method. The calculated theoretical parabolic constants at various temperatures were compared with these experimental results, and a good agreement was obtained. Some preliminary studies were also made on the morphologies of spinel particles at the nucleation stage. It was found that the triangular {111} faces of spinel particles were parallel to the surface of {0001} sapphire substrate. The product shape was consistent with the tetrahedron composed of {111} faces. The morphology of spinel particles on a sapphire substrate was more complicated in that the triangular {111} faces of spinel had to be inclined at a certain angle to the substrate in order to maintain the orientation relationship.

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Personer med könsöverskridande beteende är en grupp med större risk för psykisk ohälsa jämfört med resten av befolkningen. Ett professionellt bemötande är en viktig del av behandlingsprocessen och påverkar terapeutiskt utfall. Tidigare forskning visar brister i kontakten mellan vårdpersonal och personer med könsöverskridande beteende. Det saknas dock studier som fokuserar på psykologer och deras arbete med denna klientgrupp. Syftet med föreliggande studie är att undersöka psykologers upplevelse av klienter med könsöverskridande beteende. Studien har en kvalitativ ansats. Semistrukturerade intervjuer genomfördes med fem psykologer som hade erfarenhet av klienter med könsöverskridande beteende. Resultaten pekar på att könsöverskridande beteende är ett ämne som väcker både intresse och engagemang, men också en viss osäkerhet hos psykologer. Det framkommer att psykologers förförståelse och personliga inställningar spelar en stor roll i arbetet med klientgruppen när utbildningen och tillgången till information i ämnet är begränsad. En icke-patologiserande syn på könsöverskridande beteende dominerar, men även motsatsen förekommer. Ytterligare forskning krävs för att kartlägga på vilket sätt psykologrelaterade faktorer påverkar behandlingen av personer med könsöverskridande beteende. En annan viktig aspekt är hur befintlig kunskap kan implementeras i läroplaner för psykologers grundutbildning och effektivt spridas bland yrkesverksamma. / People with gender-incongruent behaviors have a higher risk for psychiatric problems compared to others. A professional approach is an important part of the treatment process and will influence the therapeutic outcome. Earlier research shows deficits in the contact between care personnel and people with gender-incongruent behaviours. There are no studies focusing on psychologists and their work with this client group. The aim of this study is to research psychologists’ subjective experience of clients with gender-incongruent behaviours. The study uses a qualitative method. The research data was collected with semi-structured interviews with five psychologists that had some experience with clients with gender-incongruent behaviours. The results point to gender-incongruent behaviors being a topic that evokes both interest and commitment, but also some insecurity in psychologists. Psychologists’ preconceptions and personal beliefs play a big role during the work with these clients when education and access to information on the topic is limited. A non-pathologizing outlook on gender-incongruent behaviours dominates, but the opposite also exists. More research is needed to map out in which way psychologist-related factors influence treatment of people with gender-incongruent behaviours. Another important aspect is how existing knowledge can be implemented in psychologists’ basic training and how it can be spread effectively amongst professionals.

Indiana University-Purdue University Indianapolis (IUPUI) / Empirical research on the uncanny valley has primarily been concerned with visual elements. The current study is intended to show how manipulating auditory variables of the stimuli affect participant’s ratings. The focus of research is to investigate whether an uncanny valley effect occurs when humans are exposed to stimuli that have an incongruity between auditory and visual aspects. Participants were exposed to sets of stimuli which are both congruent and incongruent in their levels of audio/visual humanness. Explicit measures were used to explore if a mismatch in the human realism of facial and vocal aspects produces an uncanny valley effect and attempt to explain a possible cause of this effect. Results indicate that an uncanny valley effect occurs when humans are exposed to stimuli that have an incongruity between auditory and visual aspects.

Scaling in green liquor handling systems is a persistent problem in many kraft mills. Scaling is commonly believed to be the result of pirssonite (Na2Ca(CO3)2∙2H2O) deposition. In this work, scale characterization was performed by analyzing 12 scale samples obtained from 10 kraft mills. Only 4 samples were identified as pirssonite while the remaining consisted of CaCO3. The predominant presence of CaCO3 in the scale samples was found to be the result of selective dissolution of Na2CO3 from pirssonite scale, leaving CaCO3 behind. Experimental studies were also conducted to study pirssonite solubility under green liquor conditions. Results obtained from these studies were used to create and validate a database for pirssonite in the OLI Systems® software to predict its formation. This database was used to generate a family of pirssonite solubility curves that can be used by the kraft mills as operational guidelines to prevent pirssonite precipitation.