Thesis (MScEng (Electrical and Electronic Engineering))--Stellenbosch University, 2008. / The nite element method (FEM) is a powerful tool for the computational analysis of a wide range of electromagnetic problems. As the complexity of the problems is increased so are the demands in terms of the computational resources required to obtain a su ciently accurate solution. In an attempt to obtain a desired accuracy at a lower computational cost adaptive and higher order methods are often employed. These methods generally entail re ning the solution only in the areas where greater complexity is required, thus decreasing the total computational demand. The adaptive nite element method is implemented and used to analyse the transverse electric cuto eigenmodes of 2D waveguiding structures. The higher order hierarchical vector basis functions that form part of this implementation are automatically generated to very high orders, with the results presented in excellent agreement to analytical ones where applicable. Accuracy to the order of numeric precision is attained. Using these adaptive methods, it is also possible to achieve improved cost e ciency of the error metrics considered with respect to storage requirements and computational cost.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: An investigation into the cause of undesired sidelobes in the 3D radiation pattern of slotted waveguide arrays is conducted. It is hypothesized that the cross-polarization of the antenna is at fault, along with the possibility that an error is made when designing a linear array. In investigating and finding a solution to the problem, the “Z-slot ” is introduced in conjunction with polarizer plates. The base components are used by a custom optimization algorithm to design reference and solution antennas. Results of the antennas are then compared to ascertain the cause and possible solutions for the unwanted sidelobes. The generic nature of the process may be used to characterize other arbitrary aperture configurations and to design larger antennas. / AFRIKAANSE OPSOMMING: ‘n Ondersoek om die oorsaak van ongewensde sylobbe in die 3D uitstraalpatroon van golfleier-antennas vas te stel. Die hipotese is dat die probleem ontstaan uit die kruis-polarisasie van die antenna, tesame met ‘n verkeerdelikke aanname dat die opstelling liniêr is. Die “Z-Gleuf” tesame met polariseringsplate word voorgestel as hulpmiddel om die moontlikke oorsake te ondersoek. ‘n Gespesialiseerde optime erings-algoritme benut hierdie basiskomponente om beide verwysings- en oplossing-antennas te ontwerp. Resultate van die ontwerpde antennas word dan vergelyk om die oorsaak van die ongewensde sylobbe te vas te stel. Die generiese aard van die proses kan toegepas word op enige gleuf-konfigurasie en om groter antennas mee te ontwerp.

Photonic Crystal structures have been heralded as a disruptive technology for the miniaturization of opto-electronic devices, offering as they do the possibility of guiding and manipulating light in sub-micron scale waveguides. Applications of photonic crystal guiding - the ability to send light around sharp bends or compactly split signals into two or more channels have attracted a great deal of attention. Other effects of this waveguiding mechanism have become apparent, and attracted much interest - the novel dispersion surfaces of photonic crystal structures allow the possibility of “slow light” in a dielectric medium, which as well as the possibility of compact optical delay lines may allow enhanced light-matter interaction, and hence miniaturisation of active optical devices. I also consider a third, more traditional type of photonic crystal, in the form of a grating for surface coupling. In this thesis, I address many of the aspects of passive photonic crystals, from the underlying theory through applied device modelling, fabrication concerns and experimental results and analysis. Further, for the devices studied, I consider both the relative merits of the photonic crystal approach and of my work compared to that of others in the field. Thus, the complete spectrum of photonic crystal devices is covered. With regard to specific results, the highlights of the work contained in this thesis are as follows: Realisation of surface grating couplers in a novel material system demonstrating some of the highest reported fibre coupling efficiencies. Development of a short “injecting” taper for coupling into photonic crystal devices. Optimisation and experimental validation of photonic crystal routing elements (Y-splitter and bend). Exploration of interfaces and coupling for “slow light” photonic crystals.

In this thesis I describe experimental work and present data on the guiding of Rubidium atoms along free-space propagating light beams as well as within hollow core glass fibres, namely photonic crystal fibres. I describe experiments, laser systems and vacuum trap assemblies designed to facilitate this guiding. These experiments are intended to aid progression within the field of cold atom guidance wherein narrow diameter, long distance hollow-fibre guides are a current goal. Realisation of these guides could lead to promising applications such as atom interferometers and spatially accurate, multi-source, atom depositors. Herein, guided fluxes are observed in free-space guiding experiments for distances up to 50mm and up to 10GHz red-detuning from resonance. Additionally hollow-core, Kagome structured, quasi- and true-photonic crystal fibres are characterised. Finally a number of detailed fibre-guiding magneto-optic traps are developed. Both cold atomic-beams and cold atomic clouds are reliably positioned above fibre entrance facets in conjunction with a guiding laser beam coupled into the fibre core. Issues regarding optical flux detection outwith fibre confinement appear to have hindered observation of guided atoms. A far more sensitive detection system has been developed for use in current, ongoing fibre-guide experiments.

This dissertation reports the application of nonlinear optical effects for the investigation of vibrational and electronic spectroscopy of molecules adsorbed on thin film metal oxide surfaces and metal oxide surfaces. The main emphasis of the experiments cited here is to introduce the recently developed multi-photon technique, Waveguide Surface Coherent anti-Stokes Raman Scattering Spectroscopy (WSCARS), to the scientific community. Planar optical waveguides have been utilized to generate large optical field enhancements on metal oxide surfaces. Guided waves have been employed to obtain the surface coherent anti-Stokes Raman scattering spectra of pyridine, phenol, benzene, methanol, CD₃OD, 2,4-pentadione, oxygen, ammonia and ND₃ adsorbed onto a ZnO (0001) surface. Vibrational spectra of transient species (O₂⁻) adsorbed on ZnO (0001) surface are also presented. Furthermore, the WSCARS has been used to monitor catalytic hydrogenation of ethylene adsorbed on ZnO (0001) surface. The WSCARS technique is compared with the other vibrational surface probes. Future directions and limitations of the technique are also discussed. Electronic spectra of surface bound species have been examined by resonantly enhanced surface second harmonic generation (SSHG). SHG spectra of trans-cinnamic acid adsorbed on optically cleaned fused silica have been obtained at room temperature and at 4 K. Surface second harmonic generation has been applied to study the adsorption of water and acetone onto thermally grown silicon dioxide/silicon surface. SSHG has been successfully applied to monitor photo-oxidation and photo-reduction of a rutile (110) surface. Experiments are described, data are presented, and surface-adsorbate binding modes are discussed.

Des structures phononiques ou cristaux phononiques constitués de réseaux ordonnés de tubes en acier favorisent l'existence de bandes interdites et de bandes passantes. Les premières sont des domaines fréquentiels où une onde incidente ne peut traverser de telles structures. En introduisant de légères variations sur le positionnement des tubes, il est possible d'élargir considérablement les bandes interdites. En faisant varier l'épaisseur des tubes dans un cristal phononique à symétrie carrée, l'effet d'une onde plane incidente parallèlement à la direction de variation est de créer de fines bandes passantes dans la bande interdite obtenue initialement lorsque les tubes ont même épaisseur. Si l'on envoie l'onde incidence perpendiculairement à la direction de variation de l'épaisseur des tubes, on crée des lentilles acoustiques convergentes ou divergentes déviant les faisceaux acoustiques. Enfin, lorsque dans un cristal composé de tubes en polyéthylène on insère une allée de tubes en acier en forme de virages, les simulations numériques montrent qu'une onde acoustique peut être guidée aux fréquences correspondant aux bandes passantes du cristal phononique entièrement en acier.

Šio baigiamo darbo objektas – gidų pasirengimas. Baigiamo darbo tikslas – apžvelgti gidų rengimo ypatumus Kauno mieste bei įvertinti turistų nuomones, apie gidų teikiamas paslaugas, gidų profesinius įgūdžius, gebėjimus. Tikslui pasiekti keliami šie uždaviniai: 1) Apžvelgti gido paslaugų kaip turizmo produkto dalies ypatumus; 2) Aptarti gidų profesinio rengimo pagrindus; 3) Ištirti Kauno miesto turistų nuomonę apie gidų paslaugas, gidų profesionalumą. Tikslui ir uždaviniams pasiekti naudojami šie tyrimo metodai: analizės, apklausos, matematinis – statistinis. Tyrimo metu nustatyta, jog geriausiai respondentų buvo įvertinti tokie gido paslaugų Kauno mieste rodikliai kaip prieinamumas, paslaugų kokybė bei informacijos sklaida; prasčiausiai - gido paslaugų įvairovė. Vertinant gidų specialiąsias žinias, pastebėta, kad geriausiai buvo įvertintos gidų retorikos, ekskursijų rengimo ir vedimo žinios, tuo tarpu prasčiausiai - psichologijos bendrosios gido žinios. Labiausiai respondentus tenkina gidų savojo temperamento ir nuotaikų valdymas, gidų pastabumas; netenkina - konfliktų prevencija ir valdymas. Anot apklaustųjų turistų, gidai Kauno mieste pasižymi, tvarkingumu, sąžiningumu, sąmoningumu, tačiau jiems trūksta kūrybingumo ir objektyvumo. Kauno miesto gidų paslaugos, lyginant su kitų Lietuvos miestų gidų paslaugomis respondentų vertinamos gerai. Visgi, Kauno miesto gidams, lyginant su kitų miestų gidais, trūksta profesionalumo, patirties, geresnio pritaikymo turistams, nuoširdumo... [toliau žr. visą tekstą] / The finishing work - For guides and training system. Finishing work - an overview of the training system guides Kaunas city and evaluate the tourist views of the courier services, courier professional skills and abilities. In order to achieve the following tasks: 1) Discuss as a tourist guide for the specific characteristics of the product; 2) Analyze the professional preparation of the guides; 3) Perform the tourist city of Kaunas reviews / evaluations of the analysis. Objectives and targets, the following methods: analysis, surveys, mathematical - statistical. The study found that most respondents assessed the following guide for the city of Kaunas indicators of access, quality of service and information-sharing; worst - guide a variety of services. The evaluation guides expertise observed that most guide books were evaluated rhetoric tour preparation and conduct of knowledge, while the lowest - the psychology of the common knowledge of the guide. Most respondents satisfied with the courier's own temperament and mood management, guide attentiveness; not satisfied - conflict prevention and management. According to the respondents tourist guides in Kaunas has, regularity, honesty, awareness, but they lack creativity and objectivity. Kaunas city guides, as compared with other Lithuanian cities courier services respondents evaluated well. However, Kaunas city guides, comparison with other city guides, lack of professionalism, experience, and better application of tourists... [to full text]

Industrial heritage tourism has been in focus for many academic studies and tourism is an alternative developmental tool for mines and contributes to their economic success. This thesis is about the Falu Mine in Dalarna, Sweden, which has World Heritage status since 2001 and is one of the biggest attractions in the region. Its history and cultural importance are reasons for the importance of preserving the heritage. The Falu Mine is under the management of the Great Copper Mountain Trust and one of their ambitions is to ensure the continuous popularity among domestic and international visitors. In order to gain a better understanding of the visitors and to find strategies to improve performance, a visitor survey has been conducted in the summer of 2011. It is the authors believe that the guides of the Falu Mine have the best available insight and that their perceptions help to add to the understanding about the visitors. Therefore, this thesis aims to explore the perceptions of the guides about their visitors, to investigate how the perceptions correspond to the statistical results and to study if there are any differences between domestic and international visitors. The mixed methods approach will increase the depth and accuracy of the results, by linking qualitative with quantitative data. The results show that differences between domestic and international visitors exist, both proven by interviews with the guides and the visitor survey. These differences occur in the factors, such as level of education of the visitors, group size and number of children in the group, knowledge of the visitors prior to and after the visit, sources of information and the fulfillment of the visitor expectations. The perceptions emphasize how these differences impact the guided tours. The guides of the Falu Mine have to be aware of those differences in order to adjust the tour accordingly, as well as the management of the Falu Mine can use this knowledge in order to identify strategies for improving performance.

Magister Artium - MA / Academic libraries worldwide are using the digital content management and information sharing LibGuides as a platform to provide and promote subject or course orientated information resources, to share knowledge, to provide information literacy education, utilize the Web 2.0 features to communicate with users to support teaching, learning and research. This study explored the use of LibGuides by four departments in the Community and Health Science (CHS) Faculty at the University of the Western Cape (UWC) among students, academics and the faculty librarian. A descriptive case study research design with a sequential explanatory mixed methods approach was adopted. As data gathering tools web based questionnaires, face to face interviews and system generated LibGuides page views were employed. Findings revealed that although the CHS librarian spent quality time to create LibGuides and to expose faculty members to them, only a few students and teaching staff actually used the LibGuides and that there was confusion between LibGuides and study or course guides. Those who used LibGuides, found the information resources they contained useful – especially course specific resources. Students and teaching staff being made aware of LibGuides demonstrated willingness to use them, thus librarians should deploy strategies to market, promote and educate users of LibGuides by amongst others, seeking collaboration. The impact of the study was revealed by a teaching staff embedding CHS LibGuides in e-learning courses, teaching staff introducing LibGuides during lectures and students approaching the CHS librarian for training. It is recommended that the CHS librarian incorporate suggested information resources into LibGuides, that LibGuides awareness should be raised, more training be done and that further research to explore the use and benefits of LibGuides at UWC be undertaken. It is recommended that library managers deploy strategies to reach out to faculties to enhance the use of library resources using LibGuides.

This study examines the factors that shape decision-making in relation to the development of Learner Teacher Support Materials (LTSMs) in South Africa by focusing on the processes that govern the development of Foundation Phase LTSMs, and on how publishers understand the educational nature of LTSMs that will lead to effective literacy acquisition. Findings are based on elite interviews with members of senior management in the publishing industry, and triangulated with interviews with authors and academic specialists of Foundation Phase. It was found that the close alignment between government directives and processes and the publishing industry form the core of all LTSM development and production, creating some symbiosis as well as restraints. Factors that shape the production of LTSMs include full compliance with the specific outcomes of the curriculum; producing LTSMs that are affordable in terms of set criteria by selection committees; selection committees that, determine acceptance of LTSMs for placement on approved lists; time frames that preclude in-depth research and trialling, a market that is deeply stratified and where this stratification is reinforced by curriculum imperatives relating to language; and the monitoring of classroom productivity through the filling in of Learner Book worksheets. Best practice strategies for literacy acquisition requires materials considerably beyond what the industry is producing for South Africa’s most disadvantaged markets, namely the English First Additional Language market. Teacher training done by both publishers and the Department of Basic Education suggest a different conceptualisation of Teachers’ Guides are required in order for professional development to take place through LTSMs.