284 research outputs found
The Portrayal of Magdalene Laundries in the Novels of V. S. Alexander and Lisa M. Odgaard
No full textTáto bakalárska práca analyzuje fakty o Magdaléniných práčovniach a porovnáva ich s vybranými literárnymi dielami zaoberajúcimi sa danou témou: The Magdalen Laundries: A Novel Inspired by True Events od Lisy M. Odgaard a The Magdalen Girls od V. S. Alexandera. Práca skúma, aké praktiky osvojené práčovňami a spoločnosťou si autori vybrali a hodnotí ich správnosť. Môžeme vyvodiť záver, že oba romány uvádzajú veľa opisov odzrkadľujúcich realitu, no zároveň do určitej miery idealizujú niektoré situácie.This bachelor's thesis analyses the facts about the Magdalene laundries and compares them with the selected works of literature dealing with the topic: The Magdalen Laundries: A Novel Inspired by True Events by Lisa M. Odgaard and The Magdalen Girls by V. S. Alexander. The work scrutinises the authors' choice of practices adopted by the laundries and society and examines their accuracy. It can be concluded that both novels present many descriptions reflecting the reality but also, to some extent, idealise some situations.Ústav moderních jazyků a literatu
Local durability optimization of a large-scale direct methanol fuel cell: catalyst layer tuning for homogeneous operation and in-operando detection of localized hydrogen evolution
No full textLifetime limitations are still penalizing direct methanol fuel cell technology, otherwise outstandingly promising for sustainable portable power generation. Strong heterogeneous performance fading, related to uneven operating conditions, is known to be exacerbated in the upscaling process towards commercial applications, especially at local level. This work applies a localized optimization strategy, previously developed on lab-scale samples, on a commercial 180 cm2 membrane electrode assembly, analysing both current and potential distribution by means of a custom macro-segmented fuel cell provided with array of reference electrodes. Analysis based on local polarization curves and impedance spectroscopy demonstrates that water distribution, leading to local dehydration as well flooded areas, drives uneven operation and fading. Consequently, platinum loading at cathode electrode has been redistributed, sensibly improving current density heterogeneity and stability (voltage decay rate decreased from 148 to 53.8 μV h−1) over a 600 h degradation tests. Then, residual fading identified at outlet regions has been investigated by means of local electrodes potential analysis, demonstrating a highly uneven operation of both electrodes. This phenomenon is discussed as the evidence of localized hydrogen evolution, which is identified for the first time during nominal galvanostatic operation and suspected to contribute to uneven fading of components
Local optimization of PEMFC and DMFC catalyst layers components for improved durability
No full textBoth proton exchange membrane (PEMFC) and direct methanol fuel cells (DMFC) technologies are limited in durability by a severe performance degradation determining a strongly localized heterogeneous components fading. Avoiding such localized early aging in critical areas could lead to improved durability for the overall device.
A custom macro-Segmented fuel cell hardware, provided with local reference electrodes, has been developed to perform a detailed local investigation of performance and durability. The analysis revealed uneven current distribution during operation, most likely due to uneven reactants and products distribution, particularly related to components localized flooding or dehydration. Inhomogeneous performance distribution showed a strong impact on MEA heterogeneous fading, revealing analogies between the two technologies. Local optimization of catalyst layers formulation and operating protocol have been developed, assisted by modeling simulations, aiming to an homogeneous operation. Important improvements have been obtained on durability, demonstrated by local degradation testing and by post-mortem analysis of samples, confirming the validity of the methodology and the large scope for improvements still available
Analysis of the effect of catalyst layer thickness on the performance and durability of platinum group metal-free catalysts for polymer electrolyte membrane fuel cells
No full textDevelopment of platinum group metal-free catalysts for polymer electrolyte membrane fuel cells is a critical target to obtain a high market share of fuel cell electric vehicles in the long term. Recent studies have proved the feasibility of new materials with high catalytic activity towards the oxygen reduction reaction, which are based on Earth-abundant and low-cost elements. The stability of these materials is now the major concern at the current state of the art: In the initial hundreds of hours of operation, in fact, a significant loss of catalyst activity is observed. In the present work, the analysis of performance and degradation of cathode catalyst layers based on metal-nitrogen-carbon materials is carried out for 150 hours. The effects of catalyst loading and ionomer content are being analyzed. Electrochemical impedance spectroscopy is adopted to gain insight into the ageing and the results are interpreted by means of a 1D physics-based model. A regime is reported to occur, in which ion, electron and oxygen transport limitations interplay and the effect of each phenomenon is distinguished on the impedance spectra and polarization curves. Degradation is shown to mainly affect the catalyst activity or the density of active sites, but also a loss of electrical and ionic conductivity is observed
Investigation of cathode catalyst layer interfaces evolution during accelerated stress tests for polymer electrolyte fuel cells
No full textTo elucidate the evolution of ionomer-Pt and ionomer-carbon interfaces during life cycle of polymer electrolyte fuel cells (PEFCs), electrodes with high surface area (HSA) and durable carbon supports underwent catalyst and carbon corrosion accelerated stress tests (ASTs) under stoichiometric and sub-stoichiometric gas flow conditions. Electrochemical characterizations, as well as X-ray photoelectron spectroscopy (XPS) were utilized to assess degree of components degradation. Catalyst AST results revealed that Pt nanoparticles dispersed within the micro- and meso-pores and not in contact with ionomer are the main contributor to the 50% electrochemical surface area (ECSA) loss observed after 30k cycles resulting in significant polarization loss, which is much more notable in the case of sub-stoichiometric operating condition. Support AST results for HSA carbon showed severe ionomer degradation and 55% ECSA loss within the first 100 cycles, while cell with durable support exhibited negligible polarization and ECSA decay during the first 2500 cycles attributed to higher ionomer coverage, preservation of proton pathways preventing Pt from detachment
Worldviews Of The Greenlanders: An Inuit Arctic Perspective. By Birgitte Sonne
No full textIn this book the author brings together all the relevant sources about the cosmology of the Greenlandic Inuit, comparing Alaskan, Eastern Inuit, and Siberian sources.This work allows access to material that is, for most people, otherwise difficult to access, and it provides valuable new insights. If anybody thought that the Greenlandic pre-colonial religion was in any way poor or simple, their view will be thoroughly shaken after reading this book.The author states that one purpose of this work was to provide a Greenland companion to the fairly recent publications about the cosmologies of Canadian and Alaskan Inuit/Yupiit, and all themes are discussed with references to the works of her counterparts in Alaska and Canada and to many other researchers.<br/
Lavanderías de magdalenas irlandesas: reclamando los cuerpos de las madres solteras en the magdalene girls (2016) de v.s Alexander y the magdalene laundries (2017) de Michelle Odgaard
No full textIf some ecofeminists defend the innate connection between women and nature we well
as the patriarchal domination of women, this article discredits, following Biehl, that
reductionist view of social relations proving that power and violence are also executed
by women over other inferior women and arguing that this approach contributes to a
greater gender division. Following Butler’s gender performativity theory, we will analyse
V.S. Alexander’s The Magdalen Girls (2016) and Lisa Michelle Odgaard’s The Magdalen
Laundries (2017), to prove that gender divisions and moral requirements have contributed
to the subjugation of Magdalene women through violence and to the negation of their role
as mothers, and yet, how that vulnerable condition could have been challenged by growing
resistant.Si algunas ecofeministas defienden la conexión innata entre la mujer y la naturaleza, así
como la dominación patriarcal, este artículo desacredita, siguiendo a Biehl, esa visión
reduccionista de las relaciones sociales probando que el poder y la violencia son también
llevados a cabo por mujeres y argumentando que este enfoque contribuye a una división
de género mayor. De acuerdo con la teoría de la perfomatividad del género de Butler,
analizaremos The Magdalen Girls (2016) de V.S. Alexander y The Magdalen Laundries
(2017) de Lisa Michelle Odgaard para probar que las divisiones de género y los requisitos
morales han contribuido a la subyugación de las Magdalenas a través de la violencia y de la
negación de su rol como madres, y, sin embargo, cómo esa condición de vulnerabilidad ha
sido desafiada al mostrar una actitud de resistencia
Repetitive Control of Individual Pitch to Reduce Wake Effect on Wind Turbines
No full textEfterhånden som windmøller bliver større, med rotordiametre over 100 m, vil vingerne dække et større vindfelt som indeholder en række forskellige vindfænomener, såsom wakes, vindforskydning, tårnskygge, hvilket vil påføre store strukturelle laster på vindmøllen.I denne these er en løftet repetitive regulator udviklet, som reducere de strukturelle laster ved brug af individuel pitching. Til dette formål er en dynamisk model af en vindmølle udledt. Modellen indeholder en aerodynamiskmodel, mekaniskmodel, en strukturelmodel og en model af pitchingsystemet. Modellen er blevet lineariseret og valideret i forhold til simulerings koden FAST.Fra modellen er en løftet repetitive regulator blevet udviklet, ved at lave en løftet system beskrivelse, og herfra blev en reduceret output-feedback formulering fundet, hvilken lagde grunden til LQR designet af regulatoren.I en accepttest blev den løftede repetitive regulator samlignet med regulatoren fra FAST som var implementeret i Matlab. Resultatet herfra var at accepttesten ikke blev godkendt, selvom bøjningen af tårn og vinger blev reduceret. Det formodes at dette skyldes en forskel mellem implementeringen i Matlab og modellen.As wind turbines get larger, with rotor diameters above 100 m, the blades will sweep a large wind field, containing different wind phenomenas such as, wakes, wind shear and tower shadow; applying a big structural load upon the wind turbine.In this thesis, a lifted repetitive controller is developed which reduces the structural loads by the use of individual pitching. For this purpose a dynamic model of a wind turbine has been developed. The model contains an aerodynamic model, mechanical model, a structural model and a model of the pitch system. The model has been linearized and validated in accordance with simulation code FAST.From the model a lifted repetitive controller was design, by making a lifted system description where made, and from this a reduced output-feedback formulation was found, making it possible to use LQR design to calculate the controller gain.In an acceptance test, the lifted repetitive controller was compared to the controller from FAST which was implemented in Matlab. The results from this were, that the controller designed did not pass, even though the deflection of tower and blades were reduced. It is assumed that it is caused by a mismatch between the model and the implementation in Matlab
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