<p>Prior to the mid-20th century, the idea of electric propulsion had been all but a foreign one that manifested itself in the topic of science fiction. It was around this time when companies and agencies like NASA began to take interest in the topic of space propulsion, as most famously seen in the landing of the Apollo 11 mission on the moon. It was not until the early-1960s where the idea of a pulsed plasma thruster was first realized, with its first test being in 1964 aboard the Russian Zond-2 satellite which contained 6 ablative Polytetrafluoroethylene (PTFE, or “Teflon”) pulsed plasma thrusters.</p> <p>In this paper, a new low-voltage, liquid-fed pulsed plasma thruster was developed, tested, and characterized. This project took influence from the previous low-voltage, liquid-fed pulsed plasma thruster in Purdue’s EPPL and desired to transition it from a current gas-fed system to its intended liquid-fed system. The two main objectives for this project included conducting direct studies of the cathode’s erosion rate using a simple weighing method after simulating a lifetime of discharging the thruster, and completing the initial design of the liquid-fed pulsed plasma thruster using AF-M315E as its propellant while gathering data on its required breakdown voltage, exhaust velocity, and specific impulse.</p> <p>Both objectives were successfully completed, with the following parameters being measured or calculated. The required breakdown voltage was seen to be less than 26kV to keep the ignition spark inside the chamber. For the subsequent results measured however, the breakdown voltage was kept between 10-16kV for all successive tests. The peak current measured for all discharges was an average of 11kA, far exceeding similar geometries such as MPD thrusters. The operational voltage was less than 200V, although an operational voltage closer to 100V is expected after further optimization of the system is completed. The erosion rate of the tungsten cathode at this operational setting was found to be 15.4046 +/- 0.592 microgram/Coulomb which is much less than the cathode spot erosion rate reported for tungsten in literature of about 60 microgram/Coulomb and is beneficial for extending system lifetime. The exhaust velocity was calculated to be 30.6 +/- 4.8km/s which is typical of state-of-the-art PPT electric propulsion devices. The specific impulse was also extrapolated from the ion’s exhaust velocity, calculating to be 3,119 +/- 489 seconds. Future work would require optimization of the propellant injection mechanism to minimize propellant loss.</p>

[ES] Las arritmias cardíacas son un problema importante para los sistemas de salud en el mundo desarrollado debido a su alta incidencia y prevalencia a medida que la población envejece. La fibrilación auricular (FA) y la fibrilación ventricular (FV) se encuentran entre las arritmias más complejas observadas en la práctica clínica. Las consecuencias clínicas de tales alteraciones arrítmicas incluyen el desarrollo de eventos cardioembólicos complejos en la FA, y repercusiones dramáticas debido a procesos fibrilatorios sostenidos que amenazan la vida infringiendo daño neurológico tras paro cardíaco por FV, y que pueden provocar la muerte súbita cardíaca (MSC). Sin embargo, a pesar de los avances tecnológicos de las últimas décadas, sus mecanismos intrínsecos se comprenden de forma incompleta y, hasta la fecha, las estrategias terapéuticas carecen de una base mecanicista suficiente y poseen bajas tasas de éxito. Entre los mecanismos implicados en la inducción y perpetuación de arritmias cardíacas, como la FA, se cree que las dinámicas de las fuentes focales y reentrantes de alta frecuencia, en sus diferentes modalidades, son las fuentes primarias que mantienen la arritmia. Sin embargo, se sabe poco sobre los atractores, así como, de la dinámica espacio-temporal de tales fuentes fibrilatorias primarias, específicamente, las fuentes focales o rotacionales dominantes que mantienen la arritmia. Por ello, se ha desarrollado una plataforma computacional, para comprender los factores (activos, pasivos y estructurales) determinantes, y moduladores de dicha dinámica. Esto ha permitido establecer un marco para comprender la compleja dinámica de los rotores con énfasis en sus propiedades deterministas para desarrollar herramientas basadas en los mecanismos para ayuda diagnóstica y terapéutica. Comprender los procesos fibrilatorios es clave para desarrollar marcadores y herramientas fisiológica- y clínicamente relevantes para la ayuda de diagnóstico temprano. Específicamente, las propiedades espectrales y de tiempo-frecuencia de los procesos fibrilatorios han demostrado resaltar el comportamiento determinista principal de los mecanismos intrínsecos subyacentes a las arritmias y el impacto de tales eventos arrítmicos. Esto es especialmente relevante para determinar el pronóstico temprano de los supervivientes comatosos después de un paro cardíaco debido a fibrilación ventricular (FV). Las técnicas de mapeo electrofisiológico, el mapeo eléctrico y óptico cardíaco, han demostrado ser recursos muy valiosos para dar forma a nuevas hipótesis y desarrollar nuevos enfoques mecanicistas y estrategias terapéuticas mejoradas. Esta tecnología permite además el trabajo multidisciplinar entre clínicos y bioingenieros, para el desarrollo y validación de dispositivos y metodologías para identificar biomarcadores multi-dominio que permitan rastrear con precisión la dinámica de las arritmias identificando fuentes dominantes y atractores con alta precisión para ser dianas de estrategias terapeúticas innovadoras. Es por ello que uno de los objetivos fundamentales ha sido la implantación y validación de nuevos sistemas de mapeo en distintas configuraciones que sirvan de plataforma de desarrollo de nuevas estrategias terapeúticas. Aunque el mapeo panorámico es el método principal y más completo para rastrear simultáneamente biomarcadores electrofisiológicos, su adopción por la comunidad científica es limitada principalmente debido al coste elevado de la tecnología. Aprovechando los avances tecnológicos recientes, nos hemos enfocado en desarrollar, y validar, sistemas de mapeo óptico de alta resolución para registro panorámico cardíaco, utilizando modelos clínicamente relevantes para la investigación básica y la bioingeniería. / [CA] Les arítmies cardíaques són un problema important per als sistemes de salut del món desenvolupat a causa de la seva alta incidència i prevalença a mesura que la població envelleix. La fibril·lació auricular (FA) i la fibril·lació ventricular (FV), es troben entre les arítmies més complexes observades a la pràctica clínica. Les conseqüències clíniques d'aquests trastorns arítmics inclouen el desenvolupament d'esdeveniments cardioembòlics complexos en FA i repercussions dramàtiques a causa de processos fibril·latoris sostinguts que posen en perill la vida amb danys neurològics posteriors a la FV, que condueixen a una aturada cardíaca i a la mort cardíaca sobtada (SCD). Tanmateix, malgrat els avanços tecnològics de les darreres dècades, els seus mecanismes intrínsecs s'entenen de forma incompleta i, fins a la data, les estratègies terapèutiques no tenen una base mecanicista suficient i tenen baixes taxes d'èxit. La majoria dels avenços en el desenvolupament de biomarcadors òptims i noves estratègies terapèutiques en aquest camp provenen de tècniques valuoses en la investigació de mecanismes d'arítmia. Entre els mecanismes implicats en la inducció i perpetuació de les arítmies cardíaques, es creu que les fonts primàries subjacents a l'arítmia són les fonts focals reingressants d'alta freqüència dinàmica i AF, en les seves diferents modalitats. Tot i això, se sap poc sobre els atractors i la dinàmica espaciotemporal d'aquestes fonts primàries fibril·ladores, específicament les fonts rotacionals o focals dominants que mantenen l'arítmia. Per tant, s'ha desenvolupat una plataforma computacional per entendre determinants actius, passius, estructurals i moduladors d'aquestes dinàmiques. Això va permetre establir un marc per entendre la complexa dinàmica multidomini dels rotors amb ènfasi en les seves propietats deterministes per desenvolupar enfocaments mecanicistes per a l'ajuda i la teràpia diagnòstiques. La comprensió dels processos fibril·latoris és clau per desenvolupar puntuacions i eines rellevants fisiològicament i clínicament per ajudar al diagnòstic precoç. Concretament, les propietats espectrals i de temps-freqüència dels processos fibril·latoris han demostrat destacar un comportament determinista important dels mecanismes intrínsecs subjacents a les arítmies i l'impacte d'aquests esdeveniments arítmics. Mitjançant coneixements previs, processament de senyals, tècniques d'aprenentatge automàtic i anàlisi de dades, es va desenvolupar una puntuació de risc mecanicista a la aturada cardíaca per FV. Les tècniques de cartografia òptica cardíaca i electrofisiològica han demostrat ser recursos inestimables per donar forma a noves hipòtesis i desenvolupar nous enfocaments mecanicistes i estratègies terapèutiques. Aquesta tecnologia ha permès durant molts anys provar noves estratègies terapèutiques farmacològiques o ablatives i desenvolupar mètodes multidominis per fer un seguiment precís de la dinàmica d'arrímies que identifica fonts i atractors dominants. Tot i que el mapatge panoràmic és el mètode principal per al seguiment simultani de paràmetres electrofisiològics, la seva adopció per part de la comunitat multidisciplinària d'investigació cardiovascular està limitada principalment pel cost de la tecnologia. Aprofitant els avenços tecnològics recents, ens centrem en el desenvolupament i la validació de sistemes de mapes òptics de baix cost per a imatges panoràmiques mitjançant models clínicament rellevants per a la investigació bàsica i la bioenginyeria. / [EN] Cardiac arrhythmias are a major problem for health systems in the developed world due to their high incidence and prevalence as the population ages. Atrial fibrillation (AF) and ventricular fibrillation (VF), are amongst the most complex arrhythmias seen in the clinical practice. Clinical consequences of such arrhythmic disturbances include developing complex cardio-embolic events in AF, and dramatic repercussions due to sustained life-threatening fibrillatory processes with subsequent neurological damage under VF, leading to cardiac arrest and sudden cardiac death (SCD). However, despite the technological advances in the last decades, their intrinsic mechanisms are incompletely understood, and, to date, therapeutic strategies lack of sufficient mechanistic basis and have low success rates. Most of the progress for developing optimal biomarkers and novel therapeutic strategies in this field has come from valuable techniques in the research of arrhythmia mechanisms. Amongst the mechanisms involved in the induction and perpetuation of cardiac arrhythmias such AF, dynamic high-frequency re-entrant and focal sources, in its different modalities, are thought to be the primary sources underlying the arrhythmia. However, little is known about the attractors and spatiotemporal dynamics of such fibrillatory primary sources, specifically dominant rotational or focal sources maintaining the arrhythmia. Therefore, a computational platform for understanding active, passive and structural determinants, and modulators of such dynamics was developed. This allowed stablishing a framework for understanding the complex multidomain dynamics of rotors with enphasis in their deterministic properties to develop mechanistic approaches for diagnostic aid and therapy. Understanding fibrillatory processes is key to develop physiologically and clinically relevant scores and tools for early diagnostic aid. Specifically, spectral and time-frequency properties of fibrillatory processes have shown to highlight major deterministic behaviour of intrinsic mechanisms underlying the arrhythmias and the impact of such arrhythmic events. Using prior knowledge, signal processing, machine learning techniques and data analytics, we aimed at developing a reliable mechanistic risk-score for comatose survivors of cardiac arrest due to VF. Cardiac optical mapping and electrophysiological mapping techniques have shown to be unvaluable resources to shape new hypotheses and develop novel mechanistic approaches and therapeutic strategies. This technology has allowed for many years testing new pharmacological or ablative therapeutic strategies, and developing multidomain methods to accurately track arrhymia dynamics identigying dominant sources and attractors. Even though, panoramic mapping is the primary method for simultaneously tracking electrophysiological parameters, its adoption by the multidisciplinary cardiovascular research community is limited mainly due to the cost of the technology. Taking advantage of recent technological advances, we focus on developing and validating low-cost optical mapping systems for panoramic imaging using clinically relevant models for basic research and bioengineering. / Calvo Saiz, CJ. (2022). Novel Cardiac Mapping Approaches and Multimodal Techniques to Unravel Multidomain Dynamics of Complex Arrhythmias Towards a Framework for Translational Mechanistic-Based Therapeutic Strategies [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182329

<p>The dissertation describes a crucial step in the development of a modern writer's identity in Sweden. It applies the French sociologist Pierre Bourdieu’s theories of the autonomous ”literary field” to the development in eighteen-eighties, one of the most important periods in Swedish literary history.</p><p>During this decade a large group of authors appeared, with August Strindberg in the front. In accordance with the dominating esthetical view of the nineteenth century, ”ideal realism”, the writers had an ethical responsibility. But they differed from their predecessors by not being loyal to the bourgeois society and its values, as codified in the concept of ”decency”, that contained, among other things, rules for what could be said in public. On the contrary, the new generation of authors attacked the bourgeoisie in novels, dramas and articles, especially in the singularly most controversial area, the regulation of sexuality and the ideals of bourgeois women.</p><p>This study argues that the new authors in their radical criticism aimed at the position of power in society traditionally upheld by the State church, which supervised education and ethical values. They did this by creating a role for themselves as young and oppressed, something that made it possible to deny any responsibility for the present state and furthermore to speak up, despite their own bourgeois background, for other oppressed groups like the working classes, the poor and women. But this also meant that they could not be successful in their ambitions to gain influence without loosing their identity. This was especially the consequence of the fact that an autonomous ”literary field” did not yet exist. That is, there were no internal literary institutions that, seemingly independent of the rest of society, decided what was ”good literature.” Instead, the singularly most important judge of interesting literature was the bourgeois public. Strindberg seems to have realised this early, and achieved an identity as ”uncontrolled”. He thereby lost his intellectual credibility, but gained a much bigger freedom to write and also got the attention of the large audience. At the same time, his writing undermined the values of decency by breaking the bourgeois society’s fundamental wall between the private and the public sphere, not least by writing what was regarded as facts about his own private life. </p><p>The conservative reaction accelerated towards the end of the decade while the authors grew more and more bitter about the public’s lack of understanding. At this point the author Verner von Heidenstam took the opportunity to declare a new literary era, dissociating his aesthetics from the one of the Eighties and proclaiming the necessity of an aristocratic, ethically indifferent literature (with himself as its leader). </p><p>Confronted with the new concept of what ought to be regarded as “modern”, the established male authors were generally quick to separate themselves from the female authors, and to identify the attacked literature solely with the one that critically discussed the situation of women in society - a description that has been largely adopted in the history of literature. A number of male authors also wrote novels separating themselves from the Eighties. Thus, they could continue into the new period, while female authors in general were silenced or forced to write in less esteemed genres (”popular literature”, children’s books). </p><p>Ultimately the result was a more distinct male domination coupled with a growing contempt for the large audience. This, in turn, created a need for internal institutions that could interpret, value and support literature - scholarships, elitist critics, and a writers’ union. These institutions subsequently were founded or developed during the nineties – all of them steps towards autonomy.</p>

The dissertation describes a crucial step in the development of a modern writer's identity in Sweden. It applies the French sociologist Pierre Bourdieu’s theories of the autonomous ”literary field” to the development in eighteen-eighties, one of the most important periods in Swedish literary history. During this decade a large group of authors appeared, with August Strindberg in the front. In accordance with the dominating esthetical view of the nineteenth century, ”ideal realism”, the writers had an ethical responsibility. But they differed from their predecessors by not being loyal to the bourgeois society and its values, as codified in the concept of ”decency”, that contained, among other things, rules for what could be said in public. On the contrary, the new generation of authors attacked the bourgeoisie in novels, dramas and articles, especially in the singularly most controversial area, the regulation of sexuality and the ideals of bourgeois women. This study argues that the new authors in their radical criticism aimed at the position of power in society traditionally upheld by the State church, which supervised education and ethical values. They did this by creating a role for themselves as young and oppressed, something that made it possible to deny any responsibility for the present state and furthermore to speak up, despite their own bourgeois background, for other oppressed groups like the working classes, the poor and women. But this also meant that they could not be successful in their ambitions to gain influence without loosing their identity. This was especially the consequence of the fact that an autonomous ”literary field” did not yet exist. That is, there were no internal literary institutions that, seemingly independent of the rest of society, decided what was ”good literature.” Instead, the singularly most important judge of interesting literature was the bourgeois public. Strindberg seems to have realised this early, and achieved an identity as ”uncontrolled”. He thereby lost his intellectual credibility, but gained a much bigger freedom to write and also got the attention of the large audience. At the same time, his writing undermined the values of decency by breaking the bourgeois society’s fundamental wall between the private and the public sphere, not least by writing what was regarded as facts about his own private life. The conservative reaction accelerated towards the end of the decade while the authors grew more and more bitter about the public’s lack of understanding. At this point the author Verner von Heidenstam took the opportunity to declare a new literary era, dissociating his aesthetics from the one of the Eighties and proclaiming the necessity of an aristocratic, ethically indifferent literature (with himself as its leader). Confronted with the new concept of what ought to be regarded as “modern”, the established male authors were generally quick to separate themselves from the female authors, and to identify the attacked literature solely with the one that critically discussed the situation of women in society - a description that has been largely adopted in the history of literature. A number of male authors also wrote novels separating themselves from the Eighties. Thus, they could continue into the new period, while female authors in general were silenced or forced to write in less esteemed genres (”popular literature”, children’s books). Ultimately the result was a more distinct male domination coupled with a growing contempt for the large audience. This, in turn, created a need for internal institutions that could interpret, value and support literature - scholarships, elitist critics, and a writers’ union. These institutions subsequently were founded or developed during the nineties – all of them steps towards autonomy.