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Free-electron lasers (FELs) are among the world's most intense artificial artificial sources of coherent light and are tunable to various wavelengths, including the X-ray spectrum. X-ray FELs (XFELs) are extremely useful for diffraction experiments to study molecules, materials, and quantum systems. A FEL consists of an electron accelerator and a structure of magnets called an undulator. The undulator has a periodic magnetic field, and when an electron beam passes through the undulator, the Lorentz force forces the electrons to oscillate and emit what is known asspontaneous undulator radiation. Initially, the undulator radiation is spontaneously emitted and incoherent. However, aAs the electrons interact with this initial spontaneous undulator radiation, they change their relative positions and form micro-bunches of electrons. These microbunches are shorter than the undulator radiation wavelength. Hence, the waves emitted by the electrons from the same microbunch arethey become in phase, meaning the radiation is now coherent with the radiation field, and the state of coherence develops. This process is known as self-amplified spontaneous emission (SASE). Due to the coherence, tThe radiation intensity grows exponentially along the undulator, forming several peaks in the radiation pulse known as SASE spikes. One technique for obtaining ultra-short laser pulses is to isolate single SASE spikes by controlling where, along the electron beam, the SASE spikes can grow. This growth limitation is archieved by modulating the electron energies, thus only allowing electrons at specific positions along the electron beam to radiate. In addition, to keep positive interference between undulator radiation from electrons with different energies, the energy modulation must be compensated with a gradient of the magnetic field amplitude of the undulator, so-called tapering. There are plans to implement this technique at one of the beamlines at the European X-ray FEL (EuXFEL) to generate attosecond X-ray pulses and study quantum systems. One goal of the design process is to choose design parameters for the electron beam's modulation amplitude and the undulator's tapering coefficient. These design parameters shall be chosen so that the XFEL will have as short pulse duration as possible while at the same time not getting too low peak power. This thesis aims to study the effect of electron energy modulation and undulator tapering on the SASE and how the modulation amplitude and the tapering coefficient affect the XFEL's peak power and pulse duration. A model was developed to simulate SASE with a modulated electron beam in a tapered undulator. With this model, a parameter scan gave the average peak power and pulse duration as functions of the modulation amplitude and the tapering coefficient. The parameter scan showed that the peak power and the pulse duration decrease as the modulation amplitude and the tapering coefficient increase. Therefore, a trade-off exists between high peak power and short pulse duration. It was possible to exclude sets of the parameters that gave too low peak power or long pulse duration. This study also found an optimum range for the tapering coefficient where the peak power had a local maximum without a significant increase in pulse duration. The physics behind this optimal tapering coefficient is also discussed in connection to the electrons' energy modulation.

Ziel dieser Arbeit ist, einen historischen Überblick über den Aufbau des Kapitalmarktes in BuH zu geben und einen kritischen und wissenschaftlichen Beitrag zu der noch relativ jungen Diskussion rund um den Transformationsprozess und dessen Auswirkungen und Ergebnissen zu leisten. Durch die Transformation des gesellschaftlichen Eigentums, die sogenannte Privatisierung, wurde der Kapitalmarkt ins Leben gerufen. Als Fazit wird auf die Auswirkungen des Transformationsprozess in Hinblick auf die gesamtwirtschaftliche Situation näher eingegangen. Die Arbeit bezieht sich auf die Entwicklung, die Besonderheiten und die Probleme des Kapitalmarktes sowie die gesetzlichen Rahmenbedingungen in BuH. Vor dem Hintergrund dieses Transformationsprozesses versucht diese Arbeit den Aufbau und die weitere Entwicklung der Börse in Sarajewo zu untersuchen und zu analysieren. Letzendlich soll beurteilt werden, ob der Transformationsprozess erfolgreich war und wo ein eventueller Nachholbedarf besteht.

Text in English with summaries and keywords in English, Afrikaans and Zulu / Presented in two volumes. Volume 2 contains colour photographs / Bibliography: (volume 1: leaves 181-219) / The history of South African ceramics of the twentieth and twenty-first centuries tends to be presented in a compartmentalised manner in that it focuses on the leading exponents within genres and is limited to an investigation of the contexts that have an immediate bearing on their oeuvres. The result is a fragmented (and sometimes biased) view of the role players, circumstances, influences and incentives that have come to define South African ceramics. The thesis introduces key contributors who have hitherto been considered in relation to crafts and fine art but whose work with ceramic materials places them firmly within the ambit of South African ceramics. It also positions and evaluates the roles of the formal and informal twentieth-century educational and training agencies that, within the constraints of imposed political dogma, produced ceramists who successfully challenged staid Western aesthetics. Particular attention is given to how the black “traditional potters” exercised agency in negotiating a contemporary (as opposed to an ethnographic) presence in which they referenced the forms, meanings and values of “traditional pottery” to meet the expectations of the collector’s market. The thesis posits that the ceramists’ quest to claim an identity (or an “indigeneity”) in the turbulent political era of the later twentieth century has parallels with the intent and outcomes of African Modernism. African Modernism, which arose in postcolonial countries, sought to challenge Western binaries of art, craft, identity and presence and typically made use of hybridity to that end. The same presence of hybridity is evident in twentieth-century South African ceramics, which must be read as an engagement with a multi-cultural society within which the ceramists sought to position themselves. The thesis illustrates the progression of hybrid features from an initially crude and superficial referencing of indigenous and African material culture to subjective translations of that culture that are presented in innovative approaches. This theme is further explored in relation to South African ceramics of the twenty-first century, and evidence suggests that some of the ceramists’ oeuvres can now be considered transcultural and even transnational. The thesis, which is by its nature an enquiry that presents new or reassessed evidence is neither a fully inclusive nor an absolutist revision of the history of ceramics. / Die geskiedenis van Suid-Afrikaanse keramiekkuns van die twintigste en een-entwintigste eeu is geneig om op ʼn onderverdeelde wyse voorgehou te word, omdat dit op die hoofeksponente in genres fokus en beperk is tot ʼn ondersoek na die kontekste wat ʼn direkte uitwerking op hul oeuvres het. Die resultaat is ʼn gefragmenteerde (en soms bevooroordeelde) beskouing van die rolspelers, omstandighede, invloede en aansporings wat Suid-Afrikaanse keramiekkuns definieer. Die tesis stel sleutelbydraers bekend wat tot dusver met handwerk en beeldende kuns verbind is, maar wie se werk met keramiekmateriale hulle sonder twyfel binne die sfeer van Suid-Afrikaanse keramiekkuns plaas. Daarbenewens posisioneer en evalueer die tesis die rolle van die formele en informele twintigsteeeuse opvoeding- en opleidingsagentskappe wat, binne die beperkings van voorgeskrewe politieke dogma, keramiste opgelewer het wat oninspirerende Westerse estetika suksesvol betwis het. Aandag word veral geskenk aan hoe die swart “tradisionele pottebakkers” bemiddeling uitgeoefen het in die verwesenliking van ʼn kontemporêre (teenoor ʼn etnografiese) teenwoordigheid waarin hulle verwys het na die vorme, betekenisse en waardes van “tradisionele pottebakkery” om aan die verwagtinge van die versamelaarsmark te voldoen. Die tesis voer aan dat daar parallelle bestaan tussen die keramis se soeke om op ʼn (inheemse) identiteit te kan aanspraak maak in die onstuimige politieke era van die latere twintigste eeu, en die oogmerke en uitkomste van Afrika-modernisme. Afrika-modernisme het in na-koloniale lande ontstaan en het beoog om Westerse binêre pare van kuns, handwerk, identiteit en teenwoordigheid te betwis; om hierdie doel te bereik is hibridisme gewoonlik gebruik. Dieselfde teenwoordigheid van hibridisme kan gesien word in Suid-Afrikaanse keramiekkuns van die twintigste eeu, wat beskou moet word as ʼn gemoeidheid met ʼn multikulturele samelewing waarin die keramiste hulself probeer posisioneer. Die tesis illustreer die vooruitgang van hibriede eienskappe, van ʼn aanvanklik onafgewerkte en oppervlakkige verwysing na inheemse en Afrika- materiële kultuur, na subjektiewe interpretasies van daardie kultuur wat in innoverende benaderings voorgehou word. Hierdie tema word verder ondersoek in verband met SuidAfrikaanse keramiekkuns van die een-en-twintigste eeu, en bewyse dui daarop dat sommige van die keramiste se oeuvres nou as transkultureel en selfs as transnasionaal beskou kan word. Die tesis, wat in wese ʼn ondersoek is wat nuwe of hersiende bewyse voorhou, is nóg ʼn ten volle inklusiewe nóg ʼn absolutistiese hersiening van die geskiedenis van keramiekkuns. / Umlando weseramiki yaseNingizimu Afrika kwikhulu leminyaka lamashumi amabili namashumi amabili nanye uvamise ukwethulwa ngendlela ehlukaniswe ngezigaba ngokuthi igxile phezu kwezingcweti ezihola phambili ngaphakathi komkhakha wezinhlobo kanti lokhu kugxile kuphela kuphenyo lwezizinda ezinomthintela osheshayo phezu kwemisebenzi yonke yalezo zingcweti. Umphumela ukhombisa umbono owehlukene (kanti ngesinye isikhathi umbono owencike kwingxenye eyodwa) wabadlalindima, wezimo, wemithelela kanye neziphembeleli ezichaza iseramiki eNingizimu Afrika. Ithesisi yethula abagaleli abasemqoka ukufika manje okudala benakiwe mayelana nemisebenzi yobuciko kanye nemisetshenzana yobuciko obuncane kodwa imisebenzi yayo yomatheriyali weseramiki ibabeka ngaphakathi komkhakha wezeseramiki eNingizimu Afrika. Lokhu kuphinde futhi kuhlole izindima zezinhlaka zemfundo nezoqeqesho ezihlelekile nezingahlelekile, lezo ngaphaklathi kwezihibhe zohlelo olumatasa lwepolitiki, lukhiqize osolwazi bezeseramiki abaphonsele inselele ngempumelelo osolwazi bezobuhle beNtshonalanga. Kugxilwe kakhulu kwindlela ababumbi bendabuko abamnyama “traditional potters” abasebenzisa ngayo ubummeli uma bexoxisana ukubonakala emsebenzini wesikhathi samanje (njengoba lokhu kuphambene ne-ethinigrafi) lapho baye bariferensa izindlela, izincazelo kanye nezinga lobugugu bobuciko bendabuko bokubumba ukufeza izinhloso ezilindelwe zemakethe yabaqoqi bomsebenzi wobuciko. Ithesisi iyasho ukuthi impokophelo yosolwazi bezeseramiki yokuzitholela uphawu oluchaza ubunjalo babo (or an “indigeneity”) esikhathini esibucayi sezepolitiki sekhulu leminyaka yamashumi amabili inezimpawu ezifanayo ngenhloso kanye nemiphumela yohlelo lwesimanjemanje sase-Afrika African Modernism. Uhlelo lwe-African Modernism, oluqhamuka kumazwe avele ngemuva kombuso wobukoloni, luphonsela inselele yezinhlelo zobuciko, yesithombe sobuciko kanye nobukhona bobuciko kanti ikakhulukazi bukhandwe ngobuciko bokuhlanganisa izinhlobo (hybridity) ezahlukile. Ubukhona bohlelo lokusebenzisa izinhlaka ezahlukile lwe-hybridity lubonakala kwimisebenzi yeseramiki yesenshuwari yamashumi amabili yaseNingizimu Afrika, okufanele ifundwe njengomsebenzi ohlanganiswe ndawonye nomphakathi wamasiko amaningi, kanti ngalo msebenzi ababumbi beseramiki bafuna ukuziphakamisa ngawo. Ithesisi ikhombisa intuthuko yezimpawu wumsebenzi oyingxubevange (hybrid) ovela kwindlela yokureferensa eluhlaza neyobuciko bamaqhinga bosiko lwendabuko lomatheriyeli wase-Afrika ukuphawula ngemisebenzi ehunyushiwe yalolo siko eyethulwe ngezindlela ezinamaqhinga amasha. Lesi sihloko siqhubekela phambili nokuhlolwa mayelana nohlelo lweseramiki eNingizimu Afrika kwisenshuwari yamashumi amabili, kanti ubufakazi buyasho ukuthi eminye imisebenzi yosolwazi bobuciko beseramiki ingathathwa njengemisebenzi ekhombisa ukushintsha amasiko kanye nokushintsha kwesizwe. Ithesisi, ngokwemvelo yayo ingumbuzo owethula ubufakazi obusha noma ubufakazi obubuyekeziwe, le thesis ayiwona umsebenzi oxuba konke futhi ayikona ukubuyekezwa kwangempela komlando weseramiki. / Art History, Visual Arts and Musicology / D. Phil. (Art)