This thesis is concerned with combustion of liquid biofuels, and possibility of using liquid biofuels for lower heat output power units. Overview of basic usable liquid biofuels in Czech Republic is executed in the beginning of the thesis. This part is focused especially on production method and energy effectivity of rape-oil methyl ester (RME) and bioethanol production. Overview of basic atomization method of liquid fuels is executed in next chapters. The focus is stressed on pneumatic atomization, especially effervescent atomization method, which was used in practical experiment. Practical part contains fossil fuel and selected biofuel (RME) combustion test executed on burner testing device. Basic combustion properties was found and test plan was made before executing the test. Various operating conditions are compared in terms of atomization quality, combustion quality and geometrical characteristics of flame. Usability of tested liquid biofuels for lower heat output power units is evaluated in the conclusion.

Thesis (PhD)--Stellenbosch University, 2012. / Includes bibliography / ENGLISH ABSTRACT: The rationale for this study emerged from a realization that conventional instructional design approaches for introducing Calculus concepts, based on the logical sequencing and structuring of the concepts, did not adequately attend to or address students’ ways of thinking. This was particularly important in a distance education environment where learners depend on instructional texts to make sense of what is being presented, often without support from tutors. The instructional design theory of Realistic Mathematics Education (RME) offered a promising approach for designing learning sequences based on actual investigations of the ways in which students think. This study’s focus was on trialling the process of RME theory-based design using the Fundamental Theorem of Calculus as an example. Curve sketching was prominent in this exercise. Applying RME required developing a hypothetical learning trajectory (HLT) while attempting to adhere to methodological guidelines of design research. In this project, the instructional designer’s conceptualization and interpretation of the derivative-integral construct has had the most immediate implications for the study. The line of inquiry has been largely didactic, in that it was framed by a need to establish ways of introducing the teaching of a mathematical concept following instructional design principles. Throughout the project, the instructional design space has been contested, broken down, rebuilt and, ultimately, enriched by the contributions of the expert teachers and the engagement of participating students. The series of design experiments have revealed knowledge about student reasoning in this learning domain in relation to four main areas of quantifying change, curve sketching, general mathematical reasoning and symbol use. The primary contribution of this research has been a deeper understanding of the extent to which RME can be used as an instruction design theory for planning and introducing a distance teaching Calculus unit. From the study, it is clear that successful adoption of the RME theory is influenced and facilitated by a number of factors, including: careful selection of the concepts and mathematical structures to be presented; a team of experts (mathematicians and mathematics subject didacticians) to research, test and develop the learning activities; opportunities for student interactions; and time and resources for effective RME adoption. More involved research is required to get to the stage of the evolution of a local instructional theory around introducing the derivative-integral relationship as expressed in the Fundamental Theorem of Calculus. / AFRIKAANSE OPSOMMING: Die rasionaal van hierdie studie het uit die besef ontstaan dat konvensionele onderrigontwerpbenaderings vir die bekendstelling van Calculus konsepte, gebaseer op die logiese ordening en strukturering van die konsepte, nie voldoende beantwoord aan die eise van hoe studente dink nie. Dit was van spesifieke belang in die geval van afstandonderwys waar hierdie studente sin moet maak van wat aangebied word, dikwels sonder die ondersteuning van tutors. Die onderrigontwerpteorie van Realistiese Wiskundeonderwys (RWO) bied belowende moontlikhede om leertrajekte te ontwerp wat gebaseer is op werklike ondersoeke van hoe studente dink. Hierdie studie se fokus was om die RWO-gebaseerde teoretiese ontwerp se proses wat die Fundamentele Stelling van Calculus as voorbeeld gebruik, uit te toets. Krommesketsing was prominent in hierdie oefening. Die toepassing van RWO het vereis dat 'n leertrajek ontwikkel moet word terwyl aan die metodologiese vereistes van die ontwikkelingsondersoekbenadering getrou gebly word. In hierdie projek het die onderrigontwerper se konseptualisering en interpretasie van die afgeleide-integraalkonstruk onmiddellike implikasies gehad vir die studie. Die lyn van ondersoek was grootliks didakties van aard. Desnieteenstaande was die instruksionele ontwerpruimte voortdurend beding, afgebreek, herbou en uiteindelik verryk deur die bydraes van die bedrewe onderwysers en die betrokkenheid van die deelnemende studente. Die reeks ontwerpeksperimente het kennis blootgelê van hoe studente in hierdie veld redeneer met betrekking tot die volgende vier hoof areas: kwantifisering van verandering, krommesketsing, algemene wiskundige beredenering en die gebruik van simbole. Die primêre bydrae van hierdie navorsing is die dieper verstaan van die mate waarin RWO gebruik kan word as 'n instruksionele ontwerpteorie vir die beplanning en bekendstelling van 'n Calculus eenheid in afstandsonderrig.Dit is duidelik vanuit die studie dat suksesvolle aanneming van die RWO teorie afhanklik is van 'n aantal faktore: 'n noukeurige seleksie van die konsepte en wiskundige strukture wat aangebied moet word; 'n span van bedrewe wiskundiges en wiskunde vakdidaktici om die leeraktiwiteite na te vors, uit te toets en te ontwikkel; geleenthede vir studente-interaksies, en tyd en bronne vir effektiewe RWO aanpassing. Verdere toegespitsde navorsing hierop is nodig om die fase te bereik van die ontluiking van 'n lokale onderrigteorie oor die bekendstelling van die afgeleide-integraal verwantskap soos uitgedruk in terme van die Fundamentele Stelling van Calculus.

Las guías coaxiales se emplean frecuentemente en la alimentación e interconexión de un elevado número de dispositivos de microondas y ondas milimétricas utilizados en numerosas aplicaciones prácticas (filtros, diplexores, multiplexores, etc.). Por ello, la caracterización rigurosa y eficiente de la excitación coaxial de dispositivos implementados en tecnología guiada es un tema de investigación muy importante que ha sido tratado ampliamente en la literatura técnica. Sin embargo, el número de contribuciones que se dedican a investigar este tema desde un punto de vista multimodal es realmente reducido. El objetivo fundamental de este trabajo consiste en la caracterización multimodal eficiente de la excitación coaxial de dispositivos implementados en guía rectangular utilizando el método BI-RME (Boundary Integral - Resonant Mode Expansion) 3D. En concreto, en este trabajo se caracterizan dos tipos de configuraciones ampliamente utilizadas en la práctica: la excitación coaxial clásica, y la excitación coaxial en configuración colineal. Este último tipo de excitación se emplea comúnmente en los denominados filtros en configuración comb-line, los cuales también son objeto de investigación en el presente trabajo. En particular, se ha desarrollado una herramienta de análisis y diseño muy eficiente desde un punto de vista computacional que permite caracterizar de forma precisa este tipo de filtros. Otro de los objetivos del presente trabajo es el análisis y el diseño de uniones en guía rectangular compensadas con postes conductores de geometría cilíndrica utilizando la técnica BI-RME 3D. Las uniones diseñadas (codos rectos, uniones en T, uniones T mágica y uniones turnstile) presentan una respuesta eléctrica óptima y, además, el trabajo desarrollado demuestra que la posición relativa del poste en la estructura es un parámetro de diseño muy importante que no se había considerado previamente en la literatura técnica dedicada a este tema. / San Blas Oltra, ÁA. (2008). Análisis y diseño de dispositivos pasivos de microondas y milimétricas en guía de ondas con excitación coaxial [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8308 / Palancia