This thesis presents a comprehensive study of Anglo-Saxon writings that contain embedded textual runic letters. Whilst all of the compositions included in this thesis have been discussed previously, this has not taken place in a single unified study. In addition, such previous studies tend to be biased heavily towards, on the one hand, treating the texts as literary constructs divorced from the manuscript page (with the runes interesting but marginal details) or, on the other, towards examining the runes alone and studying them for their linguistic and historical significance with little regard for the literary contexts in which they appear. My aim is to bridge this gap by providing close readings of the poems which focus primarily on their use of runes and the impact that this has on our understanding of both the runic and literary practices of the period. In this way, connections can be made between the different compositions in which runes are used, and a literary context can be proposed for this form of script-mixing. It is my argument that all of the works discussed in this thesis are in various ways thematically focused on acts of writing, visual communication, and the nature of the written word. The visual disconnect between the two scripts on the manuscript page allows the authors of these works to highlight the inherently written nature of their content. Moreover, the runic letters themselves are used in all of these texts specifically in order to represent the written word, in a way that roman letters are not. This thesis concludes that textual runes are consistently used throughout these works to signify not just specific letters or words that carry some importance within the texts, but simultaneously to represent the written word itself.

No description available.

This thesis confronts, explores, and attempts to meaningfully interpret a surprising nexus of stimulating cruces and paradoxes in Old English poetry and prose and Old Norse skaldic and Eddic poetry. The study focuses on the complex linguistic and literary manifestations of darkness, a complex and long-underestimated phenomenon for which the most appropriate term is ‘shadow’. Rather than operating with modern categories and traditional dichotomies (light/darkness), I attempt to approach the evidence on its own terms, working from the words, their collocations, and narrow contexts up to larger literary assessments. Furthermore, the comparative Old English/Old Norse approach can provide both contextualisation for the findings and control over what we can and cannot infer from them. Reflecting these methodologies (presented in Chapter 1), the core part of the thesis (Chapters 2-5) unfolds from semantics and style to texts and literary traditions, alternating at both stages between Old English and Old Norse. Chapters 2-3 provide an in-depth examination of the formal and stylistic features and the immediate textual environments of ‘shadow’, enabling the reconstruction of semantic values and associations. In Chapters 4-5, I conduct close readings of the most relevant and revealing Old English and Old Norse texts. My case studies are further contextualised by enlarging the focus of enquiry and correlating the deployment of ‘shadow’ with questions of manuscript context, medium (prose/verse), form (skaldic/Eddic), genre (mythological/heroic/religious), and wider literary-historical links. Chapter 6 brings together the evidence for the existence, nature, and function of a ‘shadow’ theme, or themes, in Old English and Old Norse poetic language. Evaluating the significance of the parallels between the two traditions as well as within them, I recontextualise ‘shadow’ in relation to chronology, history, inheritance, contact and influence, and society and culture. The findings also afford new perspectives that can reshape our understanding of the underlying poetics.

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / IRIG 106-86 Chapter 8 describes the standard for acquisition of MIL-STD-1553 traffic flow. All incoming words (command, status, or data) are transmitted and fill words are used to maintain continuous data output. If all incoming words are not needed, or if other data such as sampled analog data from transducers are also to be transmitted, then a different approach is warranted. Selected data from the avionics bus can be placed into predefined PCM words, eliminating the transmission of useless data, and optimizing the bandwidth available to a Class I telemetry system. The engineering considerations and constraints for avionics bus data acquisition and analysis will be explored in this paper.

The intricacies and exceptions of high vowel deletion in Old English have been the subject of much debate in recent historical phonology. Traditional philological handbooks such as Campbell (1959) describe the process within the assumptions of the Neogrammarian tradition. As such, high vowel deletion has been described as a phonological process that removes historically high and synchronically unstressed vowels after a heavy syllable, or two light syllables. However, the descriptions in these handbooks also reveal that exceptions are common, and as per the Neogrammarian tradition, these are usually assumed to be the result of analogy. In contrast, recent studies have sought to account for the exceptions in a way that lends more explanatory power (e.g. Stratal Optimality accounts including Bermúdez-Otero 2005). Such accounts have shown that there is more to the exceptions than analogy, and that phonological rules, as their synchronic activity declines, can become entangled with other morphological and phonological conditioning, due to the high levels of surface opacity that causes them to become unlearnable. Many of the accounts of high vowel deletion have focused on the West Saxon of Alfred (Early WS) and Ælfric (late WS), and recent descriptions of high vowel deletion have largely focused upon the noun declensions (e.g. Bermúdez-Otero in prep) and the weak verb preterites (Minkova 2012). In this study, I focus in particular upon the behaviour of high vowel deletion in the strong and weak verbs; including the past participles and both the present and preterites. The selected data represent the Early West Saxon dialect and also the Late Northumbrian dialect found in the Lindisfarne Gospel gloss. Discussion of the process as found in nouns and adjectives will also be incorporated. The study has two larger aims: 1. To provide an analysis of syncope for newly collected data sets from Early West Saxon and Lindisfarne verbs, and 2. To contribute to the debate surrounding how to account for morphophonological interaction within inflexional paradigms. The data reveal evidence to show that high vowel deletion is indeed suffering from the demise of its original phonological conditions in the verbs. It is not argued however that full lexicalization has yet taken place throughout the verbs. Instead, the data present a range of degrees of morphologization, within which the original phonological conditions have become supplemented by additional morphological conditions. Additional phonological conditioning is also in evidence. The Lindisfarne strong past participles, it is argued, represent a morphological category within which weight-based syncope is synchronically blocked. The wider question of how and why morphological and phonological conditions come to be added to existing phonological processes is addressed, and I argue that such phenomena result from unsustainable levels of opacity in the grammar (Anderson 1989), and that a theoretical framework that allows for the interaction of phonology and morphology within the grammar is necessary. The Optimality Theoretic analyses proposed in this study have the benefit of accounting for instances of phonologization through constraint interaction. It is also argued that the ways in which morphological category determines a) the way in which a phonological condition applies, and b) whether it applies at all, is best analysed using cophonological analyses (Anttila 2002a etc.).

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / In modern aircraft there is a proliferation of avionics buses. Some of these buses use industry wide standards such as ARINC 429 or AFDX while others are based on proprietary protocols. For many of the newer bus types there can be thousands of parameters on each bus. In a distributed data acquisition system the flight test engineer needs to record all of the data from each bus and monitor selected parameters in real time. There are numerous different approaches to acquiring, transmitting and recording data from avionics buses. In modern FTI there is also a proliferation of standards for recording and transmission including IRIG 106 Chapter 10, iNET and IENA. In this paper some common approaches to bus monitoring are compared and contrasted for popular buses such as ARINC 429, AFDX and Time Triggered Protocol. For each bus type the best approach is selected for reliable acquisition, speed of configuration, low latency telemetry and compact recording which is optimized for playback.

Ce travail présente un modèle de pile à combustible plus approprié au domaine du génie électrique. Le modèle qui en résulte doit être en mesure d'intégrer des circuits électroniques de puissance et de donner des informations plus pertinentes que les modèles empiriques de type circuit. Les phénomènes du coeur de pile à combustible ont été étudiés. Les analogies entre mécanique des fluides et électricité ont été utilisés dans ce travail. Nous avons introduit le principe du flux d'énergie à notre modèle. Ceci garantit l'analogie appropriée entre deux différents domaines de l'ingénierie. L'exigence du faible coût de calcul exige de limiter le modèle à une seule dimension. Nous avons d'abord élaboré un modèle des tubes de gaz et des canaux pour les systèmes multi-espèces, puis, nous avons procédé à la modélisation des couches de diffusion de gaz, de la couche de réaction et de la membrane. A ce stade, nous avons obtenu un nouveau modèle de type circuit équivalent d'une monocellule de pile à combustible. Pour le modèle de pile n-cellule, la façon la plus simple qui peut être trouvé dans la plupart des ouvrages est de multiplier la tension de sortie d'une cellule par n. Toutefois, nous avons choisi de développer le modèle réel d'un stack comprenant 3 cellules, autrement dit, de modéliser 3 cellules indépendantes et donc de tenir compte de l'effet du canal commun de gaz qui assure la distribution de chacune des cellules d'un stack. Nous avons décidé de mettre en ?uvre le modèle sous Matlab / Simulink, logiciel très utilisé en génie électrique. Les résultats des simulations ont montré que le modèle fonctionne bien. Les phénomènes internes de la cellule sous conditions opératoires spécifiées ont été illustrés. La tension de sortie de cellule à partir du modèle est bien en accord avec les résultats expérimentaux. L'effet du réseau de canal entre chaque cellule de la pile a été exploré. Bien que le résultat escompté ait été obtenu, nous avons remarqué que l'effet du réseau de distribution de gaz, d'une cellule à l'autre d'un stack de 3 cellules était moindre. Ceci est dû aux paramètres géométriques du canal que nous avons implanté dans notre modèle qui correspondent à la structure réelle de la cellule, et qui est bien conçu. Néanmoins, cet effet devrait être fortement accentué dans le cas de stack comprenant de nombreuses cellules. Afin de vérifier que notre modèle atteint bien les objectifs visés, l'association d'un stack de 3 cellules et d'un convertisseur est simulée. Nous avons constaté que la simulation se fait sans difficulté et que le modèle autorise l'analyse de l'interaction entre la pile à combustible et le circuit convertisseur; l'objectif de la thèse est donc accompli / This work is an effort to create a more proper model for electrical engineers. The resultant model should be able to incorporate with power electronic circuits and give more insight information than the empirical circuit models. The mechanic of the fuel cell has been studied. The analogies of cell mechanics to electrical circuits were used in this work. We introduced the principle of energy port to our model. This guaranties the proper analogy between two different engineering domains. The requirement of the low computational cost suggested us to limit the model to only one dimension. We first developed a model of gas tubes and channels for multi-species systems, then, proceeded to the gas diffusion layers, the catalysts and the membrane. At this level we obtained a new equivalent circuit model of the single cell system. For the n-cell stack model, the simplest way which can be found in most literature is to multiply the single cell output voltage by n. However, we chose to develop the real 3-cell stack model, i.e., there was 3 independent cells in the system and the effect of common channels between each cell was incorporated. We decided to implement the model in Matlab/Simulink because it is common to most electrical engineers. The simulation results showed that the model is working weil. The internaI phenomena of the cell at the specified condition were illustrated. The cell output voltage from the model is weil agreed with the experimental result. The effect of the channel network between each cell in the stack had been explored. Although the expected result was obtained, we noticed that the channel network effect to the 3-cell stack operation was very small. This is because the channel parameters that we gave to the model are from the real cell structure, which is weil designed. Nevertheless, this effect should be more observable in a stack system which has higher cell number. To prove that the model can fulfill the ultimate thesis goal, the 3-cell stack model was connected to boost converter. We found that the simulation can be done without problem. The interaction between the fuel cell and the converter circuit is revealed; the objective of the thesis is accomplished

No description available.

Σκοπός της παρούσας διπλωματικής εργασίας είναι η μελέτη ενός υβριδικού συστήματος, το οποίο αποτελείται από μια κυψέλη καυσίμου και μπαταρίες, για την τροφοδοσία ενός μεταβαλλόμενου AC φορτίου. Επίσης, μελετώνται οι διατάξεις των ηλεκτρονικών ισχύος που απαιτούνται για να γίνει εφικτή η διασύνδεση της κυψέλης καυσίμου και των μπαταριών με το AC φορτίο. Αρχικά, γίνεται αναφορά στα βασικά χαρακτηριστικά του υδρογόνου και τους λογους που οδήγησαν στην αύξηση της χρήσης του τα τελευταία κυρίως χρόνια. Ακόμα, παρουσιάζονται οι διάφορες μέθοδοι παράγωγης του υδρογόνου, το οποίο αποτελεί το καύσιμο των περισοστέρων τύπων κυψελών καυσίμου. Στη συνέχεια, ακολουθεί η δομή και η ανάλυση του τρόπου λειτουργίας των διάφορων τύπων κυψελών καυσίμου. Έπειτα, παρουσιάζονται συνοπτικά οι διακοπτικοί μετατροπείς συνεχούς ρεύματος, διατάξεις των ηλεκτρονικών ισχύος, τις οποίες χρειαζόμαστε για την εξομάλυνση και τη σταθεροποίηση σε μια επιθυμητή τιμή της τάσης εξόδου των κυψελών καυσίμου, καθώς και τη μετατροπή της συνεχούς τάσης σε εναλλασσόμενη. Ακόμα, γίνεται περιγραφή της πειραματικής διάταξης κυψελών καυσίμου 1.2kW της εταιρίας Ballard Power Systems. Η διάταξη αυτή χρησιμοποιήθηκε για τη λήψη μετρήσεων και την εξαγωγή συμπερασμάτων σχετικά με τη λειτουργία μίας κυψέλης καυσίμου τύπου PEM, τόσο στη μόνιμη όσο και τη μεταβατική κατάσταση. Επίσης, αναπτύσσεται ένα μοντέλο του υβριδικού συστήματος στο Simulink, όπου προσομοιώνονται η κυψέλη καυσίμου 1.2kW της εταιρίας Nexa και οι μπαταρίες WP18-12I της εταιρίας LONG, ως πηγές τάσης. Ως μεταβλητό AC φορτίο χρησιμοποιείται μια θερμάστρα αλογόνου, με κατανάλωση ισχύος από 450W έως 1800W. Μελετάται η συμπεριφορά τόσο της κυψέλης καυσίμου όσο και των μπαταριών στις διάφορες αυξομειώσεις του φορτίου, καθώς και η απόκριση των μετατροπέων συνεχούς ρεύματος και του αντιστροφέα. Τέλος, παρουσιάζονται τα αποτελέσματα που προέκυψαν από την προσομοίωση στο Simulink. Από τα αποτελέσματα εξάγονται συμπεράσματα για τη λειτουργία του μοντέλου και προκύπτουν πιθανές προτάσεις για τη βελτίωση της απόδοσης του συστήματος. / The purpose of the present thesis is the study of a hybrid system, that consists of a fuel cell and batteries, in order to supply a changing AC load with power. The power electronics, that are required to make possible the interconnection of the fuel cell and the batteries with the AC load, are also being studied. To begin with, there is a reference to the essential features of hydrogen and the reasons that led to its increased use, mainly in recent years. In addition to this, the different methods for hydrogen production are being displayed. Hydrogen is the fuel for most fuel cell types. Moreover, the structure and the analysis on how the various types of fuel cells operate is considered. Furthermore, there is a brief presentation on DC-DC converters, power electronic devices, that are necessary in order to normalize and stabilize at a desired value the output of the fuel cell and convert DC voltage into AC. What is more, there is a description of the experimental arrangement of the fuel cell 1.2kW of the Ballard Power Systems company. The aforementioned device was used for taking measurements and draw conclusions on the operation of a PEM type fuel cell, in both the permanent and the transitory state. Afterwards, a model of the hybrid system is being developed in Simulink. As far as the voltage sources are concerned, the 1.2kW fuel cell of the Ballard Power Systems company along with the batteries WP18-12I of the LONG company are being simulated. A halogen stove with power consumption varying from 450W to 1800W is being used as the variable AC load. The behavior of both the fuel cell and the batteries to the various load fluctuations is being studied, as well as the response of the DC converters and the inverter. Finally, the results obtained from the simulation in Simulink are being presented. From them, conclusions are drawn on the functioning of the model and possible proposals arise to improve the overall performance of the system.

Το αντικείμενο της παρούσας διατριβής ήταν η σύνθεση και ο χαρακτηρισμός νανοσύνθετων πολυμερικών μεμβρανών για την εφαρμογή τους σε κυψελίδες καυσίμου. Τα κελιά καυσίμου είναι ηλεκτροχημικές διατάξεις που μετατρέπουν με συνεχή τρόπο τη χημική ενέργεια ενός καυσίμου και ενός οξειδωτικού σε ηλεκτρική με ταυτόχρονη παραγωγή νερού. Μια πολύ σημαντική κατηγορία κελίων, είναι τα κελιά καυσίμου μεμβράνης πολυμερούς (PEMFC, Polymer Exchange Membrane Fuel Cell) τα οποία χρησιμοποιούν ως ηλεκτρολύτη μια πολυμερική μεμβράνη. Ανάλογα με τη θερμοκρασία λειτουργίας τα PEMFCs χωρίζονται σε αυτά που λειτουργούν σε θερμοκρασίες μέχρι 80ºC και στα υψηλής θερμοκρασίας που λειτουργούν στους 120-200ºC. Λειτουργία σε θερμοκρασίες πάνω από 100ºC έχει διάφορα πλεονεκτήματα, όπως αύξηση της κινητικής των αντιδράσεων, δυνατότητα χρησιμοποίησης άλλων καυσίμων εκτός από υδρογόνο, η χρήση όχι υψηλής καθαρότητας υδρογόνου και/ή χαμηλότερης ποσότητας του ακριβού καταλύτη Pt στα ηλεκτρόδια. Ένας από τους ηλεκτρολύτες για εφαρμογές σε PEMFC υψηλών θερμοκρασιών είναι το συμπολυμερές αρωματικού πολυαιθέρα με ομάδες πυριδίνης Advent TPS. Το συμπολυμερές Advent TPS έχει εξαιρετική ικανότητα σχηματισμού φιλμ, υψηλό Tg (>280ºC), υψηλή θερμική σταθερότητα (Τd>400ºC), υψηλή οξειδωτική σταθερότητα, ενώ μετά από εμποτισμό με Η3ΡΟ4 85% η ιοντική αγωγιμότητα είναι επίσης της τάξης του 10-2 S/cm. Στη παρούσα εργασία παρασκευάστηκαν νανοσύνθετες μεμβράνες, με την εισαγωγή υδρόφιλων, ανοργάνων προσθέτων στην υδρόφοβη πολυμερική μήτρα του Advent TPS με απώτερο σκοπό τη παρασκευή ενός νανοσύνθετου πολυμερικού ηλεκτρολύτη ο οποίος έχει την ικανότητα να εμποτίζεται με νερό βελτιώνοντας έτσι την αγωγιμότητα του συστήματος TPS/H3PO4.Τα ανόργανα εγκλείσματα που χρησιμοποιήθηκαν ήταν ο τροποποιημένος μοντμοριλλονίτης (H+-MMT), το οξείδιο του τιτανίου (ΤiΟ2) και το TiO2-P2O5. Οι νανοσύνθετες μεμβράνες εμφάνισαν ικανότητα εμποτισμού στο Η2Ο, οξειδωτική σταθερότητα και η ιοντική τους αγωγιμότητα ύστερα από τον εμποτισμό τους με Η3ΡΟ4 πλησίασε τη τιμή του Advent TPS. Επιπλέον στη περίπτωση των μεμβρανών με τον Η+-ΜΜΤ το H3PO4 συγκρατείται ισχυρότερα στη μεμβράνη, λόγω της μορφολογίας του ΜΜΤ, μειώνοντας έτσι το πρόβλημα διάχυσης του H3PO4 από τον ηλεκτρολύτη κατά τη διαδικασία της ψύξης του κελιού. / The objective of this thesis was the synthesis and characterization of nanocomposite membranes for use in fuel cells. Fuel cells are devices that convert the chemical energy of a fuel and an oxidant to electrical with simultaneous production of water. Polymer Exchange Membrane Fuel Cell (PEMFC) represents an important class of fuel cells, which uses a polymer membrane as its electrolyte. Operating above 150ºC has many advantages such as increased reaction rate, flexibility to use not so pure hydrogen as fuel and/or lower loading of the expensive metal (Pt) on the electrode. Advent TPS is an electrolyte for high temperature PEMFC that exhibits excellent film-forming properties, mechanical integrity, high glass transition temperature (2800C) as well as high thermal stability up to 4000 C. In addition to the above properties, Advent TPS shows high oxidative stability and acid doping ability, enabling proton conductivity in the range of 10-2 S/cm. The main goal of this thesis was to synthesize a nanocomposite electrolyte by adding inorganic, hydrophilic fillers in Advent TPS polymer matrix in order to fabricate a membrane that reveals ability to absorb water. The hydration of electrolyte can increase the proton conductivity. Inorganic fillers such as modified montmorillonite (H+-MMT), TiO2, TiO2-P2O5 were used. The nanocomposite membranes showed doping water ability, oxidative stability and proton conductivity in the range of 10-2 S/cm. Furthermore, the nanocomposite membranes with H+-MMT can retain the acid into the membrane, reducing the leaching problem during the cooling process of the cell. Finally the hybrid membranes were characterized with conventional techniques and showed thermal and mechanical stability.