No description available.

This DMA dissertation provides a pragmatic and coherent way of interpreting a piece of post-tonal music, Four Songs of Solitude, by John Harbison. In this study, a modified Schenkerian analysis, namely linear analysis, serves as a methodological tool for the performer to identify and understand the implicit focal pitches, linear progressions, musical directions, and background structures of the music. By exploring this modified Schenkerian approach to interpreting post-tonal music in-depth, the performer is expected to achieve convincing results in performance on stage.

Optimistiese self-evaluasies oor die vermoë om take uit te voer is belangrik vir sukses in verskeie aspekte van menswees. Wanneer mense sulke self-evaluasies doen en selfdoeltreffendheids-persepsies vorm maak hulle van inligting uit verskeie bronne gebruik. Volgens teorieë wat spesifiek verband hou met self-evaluasie is mense tydens die vorming van sulke persepsies omtrent die self veral afhanklik van inligting bekom deur sosiale vergelyking. Hierteenoor beklemtoon teorieë wat meer met selfdoeltreffendheid verband hou, die belangrikheid van self-verwysende inligting soos gevorm tydens prestasie-ervarings. Die doel met hierdie navorsing is om die ordening van die bronne van inligting, wat tydens die vorming van selfdoeltreffendheids-persepsies gebruik word, te ondersoek. Die resultate sal bydra om belangrike vrae te beantwoord oor die voorbereiding van mense vir die uitvoering van uitdagende take. In 'n eksperiment (N=1 723) wat op 'n Solomon-vier-groep-ontwerp geskoei is, is drie vorme van inligting wat persepsies kan beïnvloed aan drie eksperimentele groepe verskaf terwyl daar vyf kontrolegroepe was. Die effek van die ingrepe is met 'n vraelys gemeet. Die resultate toon dat selfdoeltreffendheidspersepsies meer deur selfverwysende inligting as deur sosiale vergelykings-inligting beïnvloed word. Dit is ook bevind dat die verskaffing van addisionele inligting nie 'n kumulatiewe effek tydens die vorming van selfdoeltreffendheidspersepsies het nie. Die implikasies van die resultate ten opsigte van die praktyk en teoretiese beskouinge is in die laaste instansie bespreek. / Optimistic self-evaluation regarding the ability to cany out tasks is important for success in various fields ofhuman endeavour. When people do such self-evaluations and fmm self-efficacy perceptions, they make use of information from various sources. According to theories related to self-evaluation, people engaged in forming such perceptions about themselves largely depend on information gained through social comparison. However, theories of self-efficacy emphasize the importance of self-referenced information, such as those formed through enactive attainments. The purpose of this research is to examine the collation of sources of information used in forming self-efficacy perceptions. The results will help to answer important questions about preparing people to perform challenging tasks. In an experiment (N=l 723) modelled on the Solomon Four Group Design, three types of information likely to influence perceptions were supplied to three experimental groups, while there were five control groups. The effects of the interventions were measured by means of a questionnaire. Results confirmed that perceptions of self-efficacy are more profoundly influenced by self-referenced information than by social comparisons. It was also found that additional information did not have a cumulative effect dming the forming of self -efficacy perceptions. The implications of the results with respect to practical and theoretical viewpoints are discussed in the final instance. / Psychology / D.Litt. et Phil. (Sielkunde)

Optimistiese self-evaluasies oor die vermoë om take uit te voer is belangrik vir sukses in verskeie aspekte van menswees. Wanneer mense sulke self-evaluasies doen en selfdoeltreffendheids-persepsies vorm maak hulle van inligting uit verskeie bronne gebruik. Volgens teorieë wat spesifiek verband hou met self-evaluasie is mense tydens die vorming van sulke persepsies omtrent die self veral afhanklik van inligting bekom deur sosiale vergelyking. Hierteenoor beklemtoon teorieë wat meer met selfdoeltreffendheid verband hou, die belangrikheid van self-verwysende inligting soos gevorm tydens prestasie-ervarings. Die doel met hierdie navorsing is om die ordening van die bronne van inligting, wat tydens die vorming van selfdoeltreffendheids-persepsies gebruik word, te ondersoek. Die resultate sal bydra om belangrike vrae te beantwoord oor die voorbereiding van mense vir die uitvoering van uitdagende take. In 'n eksperiment (N=1 723) wat op 'n Solomon-vier-groep-ontwerp geskoei is, is drie vorme van inligting wat persepsies kan beïnvloed aan drie eksperimentele groepe verskaf terwyl daar vyf kontrolegroepe was. Die effek van die ingrepe is met 'n vraelys gemeet. Die resultate toon dat selfdoeltreffendheidspersepsies meer deur selfverwysende inligting as deur sosiale vergelykings-inligting beïnvloed word. Dit is ook bevind dat die verskaffing van addisionele inligting nie 'n kumulatiewe effek tydens die vorming van selfdoeltreffendheidspersepsies het nie. Die implikasies van die resultate ten opsigte van die praktyk en teoretiese beskouinge is in die laaste instansie bespreek. / Optimistic self-evaluation regarding the ability to cany out tasks is important for success in various fields ofhuman endeavour. When people do such self-evaluations and fmm self-efficacy perceptions, they make use of information from various sources. According to theories related to self-evaluation, people engaged in forming such perceptions about themselves largely depend on information gained through social comparison. However, theories of self-efficacy emphasize the importance of self-referenced information, such as those formed through enactive attainments. The purpose of this research is to examine the collation of sources of information used in forming self-efficacy perceptions. The results will help to answer important questions about preparing people to perform challenging tasks. In an experiment (N=l 723) modelled on the Solomon Four Group Design, three types of information likely to influence perceptions were supplied to three experimental groups, while there were five control groups. The effects of the interventions were measured by means of a questionnaire. Results confirmed that perceptions of self-efficacy are more profoundly influenced by self-referenced information than by social comparisons. It was also found that additional information did not have a cumulative effect dming the forming of self -efficacy perceptions. The implications of the results with respect to practical and theoretical viewpoints are discussed in the final instance. / Psychology / D.Litt. et Phil. (Sielkunde)

Master of Music / Department of Music / Frank C. Tracz / This document was submitted to the Graduate School of Kansas State University as a partial requirement for the Master’s of Music Education degree. It contains information about music education philosophy, what defines quality literature, theoretical and historical analyses, and rehearsal plans for each of the three pieces that were performed on the Graduate Student Conducting Recital on Wednesday, March 11, 2009. Selections performed on the recital included in the document’s analysis portion include Four Scottish Dances by Malcolm Arnold, arranged by John Paynter, Mosaic, Op. 30 by Mario Gaetano, and Celebration Fanfare from “Stepping Stones” by Joan Tower, arranged by Jack Stamp. The analytical methods employed in this document and the rehearsal techniques listed are based on the Blocker/Miles unit studies and macro-micro-macro concepts from the Teaching Music Through Performance in Band book series.

This paper attempts to evaluate Training for Trainers (T4T) as an aid for developing healthy and sustained church planting movements (CPMs). The thesis is that Training for Trainers (T4T) can enable and sustain (by the Spirit’s power) healthy church planting movements because a discipleship process is built into the methodology that develops believers in their personal and communal growth and equips them to repeat the process with other individuals they reach. The very format of the T4T process provides a context for developing disciples inwardly and training disciples to minister outwardly. The T4T process continues over the course of months and years to systematically move believers through the essential stages of sustained church planting movements: Bridges in conversations with the lost from non-spiritual topics to the gospel in order to find those God is preparing (knowing whom to talk to and how to start) • Reproducible evangelism methods that are effective in the local context and can be learned by any new believer • Reproducible discipleship that addresses both short-term and long-term spiritual growth in a manner appropriate to the local worldview and able to be passed on by a new believer • Reproducible church models appropriate to the local context and able to be led and passed on by new believers • Leadership development and multiplication patterns that develop leaders rapidly in the context of ministry and enable the number of leaders to keep pace with the number of new churches. T4T moves each new generation of disciples (trainers) and churches through this process because it casts vision for and gives loving accountability for disciples to truly become trainers of others. It does this primarily through a three-thirds training process. T4T is training for trainers who will train trainers who will train trainers. T4T attempts to initiate movements of God in which at least four generations of new disciples and churches emerge. This paper evaluates T4T is based on case studies, survey instruments and biblical principles and then offers recommendations for CPM practitioners. / Christian Spirituality, Church History & Missiology / D. Th.(Missiology)

Thesis (MMed)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: Introduction: Of the volatile anaesthetic agents, desflurane causes the greatest degree of potentiation of the neuromuscular blocking drugs (NMB). The purpose of this study was to determine whether desflurane prolongs the effects of 3xED95 doses of rocuronium and cisatracurium to the same degree. The two NMB represent potent and less potent classes respectively. Methods: Informed, written consent was obtained from 63 adult patients scheduled for routine surgery. They were randomly allocated to one of four groups to receive either desflurane-sufentanil (end-tidal partial pressure 4.0 kPa) or propofol-sufentanil anaesthesia and either rocuronium (0.9mg/kg) or cisatracurium (0.15mg/kg). All patients received a target-controlled sufentanil infusion (0.5 ng/ml). Neuromuscular blockade was recorded using accelerometry (TOFGUARD ®, Organon) while patients recovered spontaneously to a Train-of-Four ratio of 0.9 (TOFR0.9). Data were analysed using one- and two-way analysis of variance. The main effects were the types of anaesthetic and NMB on indices of recovery. Results: Compared with propofol-sufentanil anaesthesia, mean times to recovery to T125% and TOFR0.9, were prolonged by desflurane-sufentanil (p<0.01). There were no interactions. Mean prolongation of time to TOFR0.9 was 41 min (SD 36) for cisatracurium and 26.6 min (SD 39) for rocuronium. Discussion: Whereas previous studies did not reveal prolongation of the duration of action of rocuronium by desflurane, we demonstrated a statistically significant prolongation of the spontaneous recovery times of both rocuronium and cisatracurium by desflurane. From the data we could not conclude that there was a difference between the two NMB. A power study revealed that in order to detect a difference between times to recovery to TOF0.9, a sample size of 101 subjects per group would be required. Conclusion: Desflurane prolongs the mean time to spontaneous recovery from neuromuscular blockade after 3xED95 doses of both cisatracurium (a potent NMB) and rocuronium (a less potent NMB). There was wide inter-individual variation in times to spontaneous recovery. Any difference in the mean prolongations between the different types of NMB is unlikely to be of clinical importance. / AFRIKAANSE OPSOMMING: Inleiding Van al die vlugtige narkosemiddels veroorsaak desfluraan die grootste mate van potensiasie van die neuromuskulêre blokkeermiddels. Die doel van hierdie studie was om vas te stel of desfluraan wel die effek van driedubbel die ED95 dosis van rokuronium en cisatrakurium tot dieselfde mate sal verleng. Metodiek Geskrewe ingeligte toestemming is verkry van 63 pasiënte wat voorgedoen het vir roetiene chirurgiese prosedures. Pasiënte is lukraak in een van vier groepe ingedeel om of desfluraansufentaniel (eind-gety parsieële druk 4.0 kPa) of propofol-sufentaniel narkose en of rokuronium (0.9 mg/kg) of cisatrakurium (0.15 mg/kg) te ontvang. Alle pasiënte het 'n teiken-beheerde sufentaniel infusie (0.5 ng/ml). Neuromuskulêre blokkade is waargeneem met behulp van aksellerometrie (TOF-GUARD, Organon) terwyl pasiënte spontaan herstel het tot “reeks-van-vier” verhouding (Engels “Train-of-four” ratio) 0.9 (TOFR0.9). Data analise is gedoen met behulp van een- en tweerigting analise van variansie. Resultate Desfluraan-sufentaniel het die gemiddelde hersteltyd tot T125% en TOFR0.9 verleng in vergelyking met propofol-sufentaniel. Geen interaksies is waargeneem nie. Gemiddelde verlenging van TOFR0.9 vir cisatrakurium was 41 minute (standaardafwyking 36) en vir rokuronium 26.6 minute (standaardafwyking 39). Bespreking Vorige studies kon nie vasstel of desfluraan die werkingsduur van rokuronium verleng nie. Ons het in hierdie studie vasgestel dat desfluraan wel 'n statisties beduidende verlenging in die hersteltyd van beide rokuronium en cisatrakurium veroorsaak. Ons kon egter nie 'n verskil tussen die twee neuromuskulêre agente aandui nie. 'n onderskeidingsvermoëstudie het getoon dat ten minste 101 pasiënte per groep benodig sou word om 'n beduidende verskil tussen die hersteltye tot TOFR0.9 te verkry. Gevolgtrekking Desfluraan verleng die gemiddelde hersteltyd tot spontane herstel van neuromuskulêre blokkade na driedubbele ED95 dosisse van beide cisatrakurium en rokuronium. Daar was egter groot interindividuele variasie ten opsigte van spontane hersteltyd. Enige verskille in die gemiddelde verlenging is onwaarskynlik van kliniese belang.

Dissertation (PhD)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: This thesis uses Mikhail Bakhtin's theory of dialogism, as well as postmodernism, to open up faultlines in satire, and to explore and challenge various perceptions and discourses surrounding and related to it. Both dialogism and postmodernism are used to suggest fresh approaches to satire, by repositioning it in relation to other discourses and reframing it as a complex dynamic, rather than a closed and inflexible system. Chapter 1 of the thesis opens with an historical survey of the beginnings and subsequent development of satire. It also contains a general discussion of the nature of satiric strategies and opens the door for the incorporation of postmodern perspectives into the argument. Chapter 2 contrasts the issues of morality and re-presentation in satire, arguing that satirists do not simply invite their audience to condemn, but offer them an opportunity to discover alternative worlds. The affinity between satire and postmodernism is emphasised by the postmodern predilection for modes highly favoured by satire: allegory, parody and fantasy. In Chapter 3 the issue of language and its referents is explored, starting with Saussure's theory of how the signifier and the signified function. It is argued that satire has never respected this fixed relationship, and that it is in this respect similar to deconstruction. The last part of the chapter is devoted to examining four key socio-political discourses - psychoanalysis, ideology, propaganda and political myth - in relation to satire. These four discourses are, like satire, intent on influencing the perceptions which people have of the world. The intention in juxtaposing these discourses is to create a dialogic process which will throw a fresh light on all of them, including satire itself. The four socio-political discourses named above play an important part in Animal Farm and Nineteen Eighty-Four, and are relevant to the subsequent discussion of these novels. Chapter 4 consists of a detailed discussion of Animal Farm, in which the various layers comprising the work are examined. The satirical aspects of the novel are closely related to the fabular and fairy tale elements which are an important part of its constitution. These elements or levels are juxtaposed with the historical details alluded to continuously in Animal Farm and indicate its close concern with the world outside the novel. Chapter 5 consists of a detailed exploration of Nineteen Eighty-Four, which is illuminated by a process of dialogism between the modernist ideology from which the novel springs and the postmodern perspective introduced into the thesis, as well as the four socio-political discourses mentioned earlier. The main postmodern theories used in this chapter are those of Foucault. The last section of the thesis demonstrates how Orwell's personal experience drives his satire, and relates this specifically to a discussion of utopia / dystopia in satire. / AFRIKAANSE OPSOMMING: Die Dialogiek van Satire: Fokuspunte en Breuke in Orwell se Animal Farm en Nineteen Eighty-Four: Hierdie proefskrif maak gebruik van Mikhail Bakhtin se teorie van dialogisme, sowel as die postmodernisme, om die breuke in satire bloot te le, en om die verskillende persepsies en diskoerse wat verband hou met die satire te ondersoek en te bevraagteken. Beide die dialogisme en die postmodernisme word gebruik om nuwe perspektiewe op satire te open, deur dit te herposisioneer in verhouding tot ander diskoerse en dit voor te stel in terme van 'n komplekse dinamika eerder as 'n geslote en onbuigsame sisteem. Die eerste hoofstuk van die proefskrif begin met 'n historiese oorsig van die oorspronge en daaropvolgende ontwikkeling van satire. Dit omvat ook 'n algemene bespreking van die aard van satiriese strateqiee en open die moontlikheid om postmodernistiese perspektiewe in die argument te integreer. Hoofstuk 2 kontrasteer die kwessies van moraliteit en representasie in satire met mekaar; daar word geargumenteer dat satirici nie net hulle gehore uitnooi om te veroordeel nie, maar hulle die geleentheid gee om alternatiewe werelde te ontdek. Die verwantskap tussen satire en postmodernisme word benadruk deur die postmodernisme se voorliefde vir die modi waaraan die satire so dikwels voorkeur gee: allegorie, parodie en fantasie. In hoofstuk 3 word die kwessie van taal en referensialiteit ondersoek, beginnende by Saussure se teorie oor die funksionering van die betekenaar en die betekende. Daar word geargumenteer dat satire nog nooit die vaste verhouding tussen betekenaar en betekende eerbiedig het nie, en dat dit in hierdie opsig verwant is aan die dekonstruksie. Die laaste gedeelte van die hoofstuk word gewy aan 'n ondersoek van vier sentrale sosio-politiese diskoerse - psigoanalise, ideologie, propaganda en politieke mitologie - in verhouding met satire. Hierdie vier diskoerse is, soos satire, daarop ingestel om mense se persepsies/opvattings van die. wereld te verander. Die doelstelling met die jukstaposisie van hierdie diskoerse is die skep van 'n dialogiese proses wat al vier hierdie diskoerse, insluitende satire, in 'n nuwe lig sal stel. Die genoemde sosio-politiese diskoerse speel 'n belangrike rol in Animal Farm en Nineteen Eighty-Four, en is relevant vir die daaropvolgende bespreking van die romans. Hoofstuk 4 bestaan uit 'n gedetailleerde bespreking van Animal Farm, waarin daar ondersoek ingestel word na die verskillende lae waaruit die roman bestaan. Die satiriese aspekte van die roman word in noue verband gebring met die fabulere en die feeverhaalelemente wat so 'n belangrike deel uitmaak van die roman se samestelling. Hierdie elemente of vlakke word gejukstaponeer met die historiese detail waarna daar deurlopend in Animal Farm verwys word en wat die noue bemoeienis met die wereld buite die roman aandui. Hoofstuk 5 bestaan uit 'n intensiewe ondersoek van Nineteen Eighty-Four, wat belig word deur 'n proses van dialogisme tussen die modernistiese ideologie waaruit die roman spruit en die postmodernistiese perspektiewe wat in die proefskrif ingevoer word. Die belangrikste postmodernistiese teoriee wat in hierdie hoofstuk gebruik word, is die van Foucault. Die laaste afdeling van die proefskrif demonstreer hoedat Orwell se persoonlike ervaring bepalend is vir sy satire en bring dit spesifiek in verband met 'n bespreking van utopie/distopie in satire.

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The aims of this thesis are to identify all possible modes of operaton for a multi-stage axial flow compressor; then to characterise the performance, attempt to numerically model operation, and determine the main flow field features for each mode. Four quadrant axial flow compressor operation occurs when the direction of flow through the compressor or the sign of the pressure difference across the compressor reverses, or any combination of these. Depending on the direction of rotation of the compressor, six modes of operation are possible in the four quadrants of the performance map. The rotor rotates in the design direction for three modes, and in the opposite direction for the other three. The stationary-rotor pressure characteristic is S-shaped and passes through the second and fourth quadrants. A three-stage axial flow compressor operating in the incompressible flow regime was used for the experimental investigation. Flow through the compressor was reversed or augmented by means of an auxiliary axial flow fan. Compressor performance was measured by means of static pressure tappings, a turbine anemometer calibrated to measure forward and reversed volumetric flow and a load cell for torque measurement. The inter-blade row flow fields were measured with pneumatic probes and 50 μm cylindrical hot film probes. Three dimensional single blade-passage Navier-Stokes simulations were performed using the Numeca FineTurbo package. Steady state simulations used a mixing plane approach. A nonlinear harmonic approximation was used for time-unsteady simulations. Unstalled first quadrant operation was unremarkable, and good agreement was obtained between experimental and numerical data. A single stall cell was detected experimentally during stalled operation, which was not modelled numerically. In the fourth quadrant for positive rotation, (windmilling), the compressor acts as an inefficient turbine. Flow separates from the pressure surface of the blade, rendering the steady-state mixing plane approach unsuitable. The performance characteristic curves for second quadrant for positive rotation, are discontinuous with those of first quadrant operation. The temperature rise in the working fluid is significantly higher than at design point. Periodic flow structures occurring across two blade passages were detected at all flow coefficients investigated, invalidating numerical modelling assumptions. Better agreement was obtained between experimental and numerical data from a case found in literature. If the compressor operates as a compressor in reverse (third quadrant operation), significant separation occurs on the pressure surface of all blades, and flow conditions resemble severe first quadrant stall. Separation becomes less severe at larger flow rates, allowing numerical simulation, though this is sensitive to the initial flow field. In the the part of the second quadrant, where the compressor rotates in reverse, it operates as a turbine. The blade angles and the direction of curvature match the flow angles and turning well, leading to high turbine efficiencies. Numerical simulations yielded good agreement with measured results, but were again sensitive to the initial flow field. Fourth quadrant operation with negative rotation occurs when flow is forced through the compressor in the design direction. Large separation bubbles are attached to the pressure surfaces of rotor and stator blades, so virtually all throughflow occurs near the hub and casing / AFRIKAANSE OPSOMMING: Die doelwitte van hierdie tesis is om al die moontlike werkmodusse vir ’n bestaande multi-stadium aksiaalvloei kompressor uit te ken; om dan die gedrag te gekarakteriseer, ’n poging aan te wend om die werking numeries te modelleer, en die belangrikste vloeiveldkenmerke vir elke modus te bepaal. Vier-kwadrant aksiaalvloei kompressor werking vind plaas as die rigting van die vloei deur die kompressor, of die teken van die drukverskil oor die kompressor omkeer, of enige kombinasie daarvan. Afhangende van die rigting van rotasie van die kompressor is ses operasionele modusse moontlik in die vier kwadrante van die kompressorkaart. Die rotor draai in die ontwerprigting vir drie van die modes, en in die teenoorgestelde rigting vir die ander drie. Die stilstaande-rotor drukkarakteristiek is S-vormig gaan deur die tweede en vierde kwadrante. ’n Drie-stadium onsamedrukbare vloei aksiaalvloei kompressor is vir die eksperimentele ondersoek gebruik. Vloei deur die kompressor is omgekeer of aangehelp deur middel van ’n aksiaalvloei hulpwaaier. Kompressor werking is gemeet deur middel van statiese druk meetpunte in die omhulsel, ’n turbine anemometer wat gekalibreer is om vorentoe en omgekeerde volumetriese vloei te meet, en ’n lassel vir wringmoment meting. Interlemryvloeivelde is opgemeet met pneumatiese sensors en 50-μm silindriese warm film sensors. Drie-dimensionele Navier-Stokes simulasies is uitgevoer vir ’n enkele lem van elke lemry, met behulp van die Numeca FineTurbo sagtewarepakket. ’n Mengvlakbenadering is gebruik vir bestendige toestand simulasies, terwyl ’n nie-linere harmoniese benadering gebruik is vir die tyd-afhanklike simulasies. Ongestaakte eerste kwadrant werking was alledaags, en goeie ooreenkoms is gevind tussen die eksperimentele en numeriese data. ’n Enkele staak-sel is eksperimenteel ontdek tydens gestaakte werking. Gestaakte werking is nie numeries gemodelleer nie. In die vierde kwadrant vir positiewe rotasie, (”windmeulwerking”), werk die kompressor as ’n ondoeltreffende turbine. Vloei-wegbrekinging op die lem drukoppervlaktes maak die bestendige toestand mengvlakbenadering ongeskik. In die kenlyne vir tweede kwadrant positiewe rotasie, is daar ’n diskontinu¨ıteit in die prestasie karakteristiekkrommes vir die eerste en tweede kwadrant werking. Die temperatuurstyging in die werk- vloeistof is beduidend ho¨er as as by die ontwerppunt. Periodiese vloeistrukture wat oor twee lemme plaasvind is gevind by alle vloei ko¨effisi¨ente wat ondersoek is, en dit maak die numeriese modellering aannames ongeldig. Beter ooreenkoms tussen die eksperimentele en numeriese data iss verkry met ’n geval wat uit die literatuur gevind is. Indien die kompressor werk as ’n kompressor in omgekeerde (derde kwadrant weking), vind beduidende wegbreking op die drukoppervlak van al die lemme plaas, wat lyk soos ernstige gestaakte eerste kwadrant werking. Die vloeiskeiding raak minder ernstig by ’n groter vloeitempo, wat numeriese nabootsing toelaat, maar die nabootsings is sensitief vir die aanvanklike vloeiveld. In die tweede kwadrant, by omgekeerde rotasie, werk die kompressor as ’n turbine. Die lemhoeke en die rigting van lemkromming stem ooreen met die vloeihoeke en verwringing, wat lei tot ho¨er turbine doeltreffendheid. Numeriese nabootsings stem goed ooreen met gemete resultate, maar is weereens sensitief vir die keuse van die aanvanklike vloeiveld. Vierde kwadrant werking met negatiewe rotasie vind plaas wanneer die lug gedwing word om deur die kompressor in die ontwerprigting te vloei. Groot skeidingborrels sit vas aan die drukoppervlaktes van alle lemme, sodat meeste deurvloei naby die naaf en die omhulsel plaas vind.

In this thesis, exergy based SI engine model optimisation (EBSIEMO) is studied and evaluated. A four-stroke bi-fuel spark ignition (SI) engine is modelled for optimisation of engine performance based upon exergy analysis. An artificial neural network (ANN) is used as an emulator to speed up the optimisation processes. Constrained particle swarm optimisation (CPSO) is employed to identify parameters such as equivalence ratio and ignition time for optimising of the engine performance, based upon maximising 'total availability'. In the optimisation process, the engine exhaust gases standard emission were applied including brake specific CO (BSCO) and brake specific NOx (BSNOx) as the constraints. The engine model is developed in a two-zone model, while considering the chemical synthesis of fuel, including 10 chemical species. A computer code is developed in MATLAB software to solve the equations for the prediction of temperature and pressure of the mixture in each stage (compression stroke, combustion process and expansion stroke). In addition, Intake and exhaust processes are calculated using an approximation method. This model has the ability to simulate turbulent combustion and compared to computational fluid dynamic (CFD) models it is computationally faster and efficient. The selective outputs are cylinder temperature and pressure, heat transfer, brake work, brake thermal and volumetric efficiency, brake torque, brake power (BP), brake specific fuel consumption (BSFC), brake mean effective pressure (BMEP), concentration of CO2, brake specific CO (BSCO) and brake specific NOx (BSNOx). In this model, the effect of engine speed, equivalence ratio and ignition time on performance parameters using gasoline and CNG fuels are analysed. In addition, the model is validated by experimental data using the results obtained from bi-fuel engine tests. Therefore, this engine model was capable to predict, analyse and useful for optimisation of the engine performance parameters. The exergy based four-stroke bi-fuel (CNG and gasoline) spark ignition (SI) engine model (EBSIEM) here is used for analysis of bi-fuel SI engines. Since, the first law of thermodynamic (the FLT), alone is not able to afford an appropriate comprehension into engine operations. Therefore, this thesis concentrates on the SI engine operation investigation using the developed engine model by the second law of thermodynamic (the SLT) or exergy analysis outlook (exergy based SI engine model (EBSIEM)) In this thesis, an efficient approach is presented for the prediction of total availability, brake specific CO (BSCO), brake specific NOx (BSNOx) and brake torque for bi-fuel engine (CNG and gasoline) using an artificial neural network (ANN) model based on exergy based SI engine (EBSIEM) (ANN-EBSIEM) as an emulator to speed up the optimisation processes. In the other words, the use of a well trained an ANN is ordinarily much faster than mathematical models or conventional simulation programs for prediction. The constrained particle swarm optimisation (CPSO)-EBSIEM (EBSIEMO) was capable of optimising the model parameters for the engine performance. The optimisation results based upon availability analysis (the SLT) due to analysing availability terms, specifically availability destruction (that measured engine irreversibilties) are more regarded with higher priority compared to the FLT analysis. In this thesis, exergy based SI engine model optimisation (EBSIEMO) is studied and evaluated. A four-stroke bi-fuel spark ignition (SI) engine is modelled for optimisation of engine performance based upon exergy analysis. An artificial neural network (ANN) is used as an emulator to speed up the optimisation processes. Constrained particle swarm optimisation (CPSO) is employed to identify parameters such as equivalence ratio and ignition time for optimising of the engine performance, based upon maximising 'total availability'. In the optimisation process, the engine exhaust gases standard emission were applied including brake specific CO (BSCO) and brake specific NOx (BSNOx) as the constraints. The engine model is developed in a two-zone model, while considering the chemical synthesis of fuel, including 10 chemical species. A computer code is developed in MATLAB software to solve the equations for the prediction of temperature and pressure of the mixture in each stage (compression stroke, combustion process and expansion stroke). In addition, Intake and exhaust processes are calculated using an approximation method. This model has the ability to simulate turbulent combustion and compared to computational fluid dynamic (CFD) models it is computationally faster and efficient. The selective outputs are cylinder temperature and pressure, heat transfer, brake work, brake thermal and volumetric efficiency, brake torque, brake power (BP), brake specific fuel consumption (BSFC), brake mean effective pressure (BMEP), concentration of CO2, brake specific CO (BSCO) and brake specific NOx (BSNOx). In this model, the effect of engine speed, equivalence ratio and ignition time on performance parameters using gasoline and CNG fuels are analysed. In addition, the model is validated by experimental data using the results obtained from bi-fuel engine tests. Therefore, this engine model was capable to predict, analyse and useful for optimisation of the engine performance parameters. The exergy based four-stroke bi-fuel (CNG and gasoline) spark ignition (SI) engine model (EBSIEM) here is used for analysis of bi-fuel SI engines. Since, the first law of thermodynamic (the FLT), alone is not able to afford an appropriate comprehension into engine operations. Therefore, this thesis concentrates on the SI engine operation investigation using the developed engine model by the second law of thermodynamic (the SLT) or exergy analysis outlook (exergy based SI engine model (EBSIEM)) In this thesis, an efficient approach is presented for the prediction of total availability, brake specific CO (BSCO), brake specific NOx (BSNOx) and brake torque for bi-fuel engine (CNG and gasoline) using an artificial neural network (ANN) model based on exergy based SI engine (EBSIEM) (ANN-EBSIEM) as an emulator to speed up the optimisation processes. In the other words, the use of a well trained an ANN is ordinarily much faster than mathematical models or conventional simulation programs for prediction. The constrained particle swarm optimisation (CPSO)-EBSIEM (EBSIEMO) was capable of optimising the model parameters for the engine performance. The optimisation results based upon availability analysis (the SLT) due to analysing availability terms, specifically availability destruction (that measured engine irreversibilties) are more regarded with higher priority compared to the FLT analysis.