Facial Artery Musculomucosal Flap in Skull Base Reconstruction Xie L. MD, Lavigne F. MD, Rahal A. MD, Moubayed SP MD, Ayad T. MD Introduction: Failure in skull base defects reconstruction can have serious consequences such as meningitis and pneumocephalus. The nasoseptal flap is usually the first choice but alternatives are necessary when this flap is not available. The facial artery musculomucosal (FAMM) flap has proven to be successful in head and neck reconstruction but it has never been reported in skull base reconstruction. Objective: To show that the FAMM flap can reach some key areas of the skull base and be considered as a new alternative in skull base defects reconstruction. Methods: We conducted a cadaveric study with harvest of modified FAMM flaps, endoscopic skull base dissection and maxillectomies in 13 specimens. Measures were taken for each harvested FAMM flap. Results: The approximate mean area for reconstruction from the combination of the distal FAMM and the extension flaps is 15.90 cm2. The flaps successfully covered the simulated defects of the frontal sinus, the ethmoid areas, the planum sphenoidale, and the sella turcica. Conclusion: The FAMM flap can be considered as a new alternative in the reconstruction of skull base defects. Modifications add extra length to the traditional FAMM flap and can contribute to a tighter seal of the defect as opposed to the FAMM flap alone. / Le lambeau musculomuqueux de la joue dans la reconstruction de la base du crâne Xie L. MD, Lavigne F. MD, Rahal A. MD, Moubayed SP MD, Ayad T. MD Introduction: Un échec dans la reconstruction de la base du crâne peut avoir des conséquences graves telles que la méningite ou la pneumocéphalie. Le premier choix de la reconstruction est le lambeau nasoseptal. Lorsque ce dernier n’est pas disponible, d’autres alternatives sont nécessaires. Le lambeau musculomuqueux de la joue (FAMM) a une place établie dans la reconstruction des déficits de la tête et du cou, mais il n’a pas jamais été décrit dans la reconstruction de la base du crâne. Objectif: Démontrer que le lambeau de FAMM peut atteindre des zones clés de la base du crâne et être considéré comme une nouvelle option de reconstruction de cette région. Méthode: Nous avons entrepris une étude cadavérique avec prélèvement de lambeaux de FAMM modifiés et une dissection endoscopique de la base du crâne sur 13 spécimens. Des mesures ont été prises pour chaque lambeau prélevé. Résultats: L’aire de reconstruction moyenne du lambeau de FAMM et des extensions est de 15.90 cm2. Les lambeaux couvrent totalement les déficits simulés du sinus frontal, des ethmoïdes, le toit du sphénoïde et la selle turcique. Conclusion: Le lambeau de FAMM peut être considéré comme une nouvelle alternative dans la reconstruction des déficits de la base du crâne. Les modifications apportent une longueur additionnelle et contribuent à une couverture plus étanche du déficit que le lambeau de FAMM seul.

The main theme of the diploma thesis is simulated accident of a truck transporting pressure barrels with chlorine.The study is focused on evaluating the effects of the accident on the lives and health of the local population and assessing the risks (and the level of hazards) with the use of selected methods.In this study, the truck accident is described in detail and the risks are evaluated through using the IAEA-TECDOC-727 method, which is based on quantitative risk assessment of sources according to the level of hazard to lives.

Made available in DSpace on 2015-03-03T13:59:44Z (GMT). No. of bitstreams: 1 GabriellJMA_DISSERT.pdf: 1371633 bytes, checksum: 92e16086f0ca63a45223381e044469ad (MD5) Previous issue date: 2012-03-05 / In February 2011, the National Agency of Petroleum, Natural Gas and Biofuels (ANP) has published a new Technical Rules for Handling Land Pipeline Petroleum and Natural Gas Derivatives (RTDT). Among other things, the RTDT made compulsory the use of monitoring systems and leak detection in all onshore pipelines in the country. This document provides a study on the method for detection of transient pressure. The study was conducted on a industrial duct 16" diameter and 9.8 km long. The pipeline is fully pressurized and carries a multiphase mixture of crude oil, water and natural gas. For the study, was built an infrastructure for data acquisition and validation of detection algorithms. The system was designed with SCADA architecture. Piezoresistive sensors were installed at the ends of the duct and Digital Signal Processors (DSPs) were used for sampling, storage and processing of data. The study was based on simulations of leaks through valves and search for patterns that characterize the occurrence of such phenomena / Em fevereiro de 2011, a Ag?ncia Nacional de Petr?leo, G?s Natural e Biocombust?veis (ANP) publicou o novo Regulamento Tecnico de Dutos Terrestres para Movimenta??o de Petr?leo, Derivados e Gas Natural (RTDT). Entre outros aspectos, o RTDT tornou obrigat?rio o emprego de sistemas de monitoramento e detec??o de vazamentos em todos os dutos terrestres do pa?s. Este documento traz um estudo sobre o m?todo de detec??o por transiente de press?o. O estudo foi realizado num duto industrial de 16" de di?metro e 9,8 Km de extens?o. O duto e totalmente pressurizado e transporta uma mistura multif?sica de ?leo bruto, ?gua e g?s natural. Para a realiza??o do estudo, foi constru?da uma infraestrutura de aquisi??o de dados e valida??o de algoritmos de detec??o. O sistema foi concebido com arquitetura SCADA. Sensores piezoresistivos foram instalados nas extremidades do duto e Processadores Digitais de Sinais (DSPs) foram usados para a amostragem, armazenamento e processamento dos dados. O estudo se baseou na realiza??o de simula??es de vazamentos por meio de valvulas e busca por padr?es que caracterizassem a ocorr?ncia de tais fen?menos

Introdução. A Aprotinina parece reduzir o uso de transfusões, o processo inflamatório e o dano miocárdico, pós-CEC. Material e Métodos. Estudo prospectivo randomizado em crianças de 30 dias a 4 anos de idade, submetidas à correção de cardiopatia congênita acianogênica, com CEC e divididas em dois grupos, um denominado Controle (n=9) e o outro, Aprotinina (n=10). Neste, a droga foi administrada imediatamente antes da CEC. A resposta inflamatória sistêmica e disfunções hemostáticas e multiorgânicas foram analisadas por marcadores clínicos e bioquímicos. Foram consideradas significantes as diferenças com p<0,05. Resultados. Os grupos foram semelhantes quanto às variáveis demográficas e intra-operatórias, exceto por maior hemodiluição no Grupo Aprotinina. Não houve benefício quanto aos tempos de ventilação pulmonar mecânica, permanência no CTIP e hospitalar, nem quanto ao uso de inotrópicos e função renal. A relação PaO2/FiO2 (pressão parcial de oxigênio arterial/fração inspirada de oxigênio) apresentou queda significativa com 24 h PO, no Grupo Controle. Ocorreu preservação da concentração plaquetária com a Aprotinina enquanto no grupo Controle houve plaquetopenia desde o início da CEC. As perdas sangüíneas foram semelhantes nos dois grupos. No grupo Aprotinina surgiu leucopenia significativa, em CEC, seguida de leucocitose. Fator de necrose tumoral alfa (TNF-) , Interleucinas (IL)-6, IL-8, IL-10, proporção IL-6/IL-10, troponina I cardíaca (cTnI), fração MB da creatinofosfoquinase (CKMB), transaminase glutâmico-oxalacética (TGO) e fração amino-terminal do peptídio natriurético tipo B (NT-proBNP) não apresentaram diferenças marcantes intergrupos. A proporção IL-6/IL-10 PO aumentou no grupo Controle. A lactatemia e acidose metabólica pós-CEC foi mais intensa no grupo Aprotinina. Não houve complicações com o uso da Aprotinina. Conclusão. A Aprotinina não minimizou as manifestações clínicas e os marcadores séricos de resposta inflamatória sistêmica e miocárdicos, mas preservou quantitativamente as plaquetas. / Introduction. Aprotinin seems to reduce the need for transfusion, the inflammatory process and myocardial damage after extracorporeal circulation (ECC). Material and Methods. A prospective randomized study was conducted on children aged 30 days to 4 years submitted to correction of acyanogenic congenital heart disease with ECC and divided into two groups: Control (n=9) and Aprotinin (n=10). In the Aprotinin Group the drug was administered immediately before ECC and the systemic inflammatory response and hemostatic and multiorgan dysfunctions were analyzed on the basis of clinical and biochemical markers. Differences were considered to be significant when P<0.05. Results. The groups were similar regarding demographic and intraoperative variables, except for a greater hemodilution in the Aprotinin Group. The drug had no benefit regarding time of mechanical pulmonary ventilation, permanence in the postoperative ICU and length of hospitalization, or regarding the use of inotropic drugs and renal function. The partial arterial oxygen pressure/inspired oxygen fraction ratio (PaO2/FiO2) was significantly reduced 24 h after surgery in the Control Group. Platelet concentration was preserved with the use of Aprotinin, whereas thrombocytopenia occurred in the Control Group since the beginning of ECC. Blood loss was similar for both groups. Significant leukopenia was observed in the Aprotinin Group during ECC, followed by leukocytosis. Tumor necrosis factor alpha (TNF-), interleukins (IL)-6, IL-8, IL-10, IL-6/IL-10 ratio, cardiac troponin I (cTnI), creatine kinase MB fraction (CKMB), glutamic-oxaloacetic transaminase (GOT) and the aminoterminal fraction of natriuretic peptide type B (NT-proBNP) ndid not differ significantly between groups.The postoperative IL-6/IL-10 fraction increased significantly in the Control Group. Post-ECC blood lactate concentration and metabolic acidosis was more intense in the Aprotinin Group. There were no complications with the use of Aprotinin. Conclusion. Aprotinin did not minimize the clinical manifestations or serum markers of the inflammatory, systemic and myocardial response, but quantitatively preserved the platelets.

Orientador: Edevar Luvizotto Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-05T20:04:30Z (GMT). No. of bitstreams: 1 Palhares_JulianaBarbosa_M.pdf: 1136611 bytes, checksum: 85a62466425d6655acb5af5bcc414c66 (MD5) Previous issue date: 2005 / Resumo: Nos sistemas de transporte de fluido líquido, têm-se a preocupação em combater às fugas ou vazamentos. Dessa fonna, este trabalho tem como objetivo aperfeiçoar o método de detecção de fugas em tubulações pelo método de resposta nos domínios fteqüência e tempo, utilizando como ferramentas matemáticas o Método da Matriz Transferência / Resposta em Freqüência e o Método das Características / Transfonnada Rápida de Fourier, sendo demonstradas as vantagens e desvantagens de cada método. E, como contribuição original, propõe um método de detecção de fugas através da análise de pulso de Alta Freqüência, localizando as fugas através da detenninação do tempo que um pulso emitido pela válvula leva para percorrer toda a tubulação e retomar à esta, denominado como Pulso Refletido / Abstract: In liquid fluid transport systems, there is a concem about avoiding leaks. Thus, this work has as objective to improve the leak detection method in pipes by úequency and time domains response method, being used as mathematical tools the method ofTransfer-Matrix / by úequency response and the Method of Characteristics / the Fast Fourier Transform, being demonstrated the advantages and disadvantages of each method. And, as new contribution, propose a leak detection method through the analysis of high frequency pulse, detecting the leaks through determination of time that a pulse produced by the valve takes to go through all pipe and come back, is denominated as a reflected pulse / Mestrado / Recursos Hidricos / Mestre em Engenharia Civil

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2017-05-02T11:34:44Z No. of bitstreams: 0 / Made available in DSpace on 2017-05-02T11:34:44Z (GMT). No. of bitstreams: 0 / Dentre as diversas aplicações dos radioisótopos, a utilização dos radiotraçadores é considerada uma das mais importantes, no diagnóstico de funcionamento dos equipamentos de processos, em plantas de indústrias químicas e petroquímicas. Os radiotraçadores são utilizados em procedimentos analíticos para obtenção de dados qualitativos e quantitativos de sistemas, em estudos de transferências físicas e físico-químicas. Na produção de radioisótopos gasosos utilizados como traçadores em processos industriais, destacam-se o 41Ar e 79Kr, gases nobres (inertes) que possuem baixa reatividade com os demais elementos químicos. O 41Ar é um emissor gama de alta energia (1,29 MeV) e apresenta elevada porcentagem de transformações com essa energia, o que resulta em quantidades relativamente pequenas necessárias em relação a outras para uma detecção eficaz, mesmo em componentes com grandes espessuras. Atualmente, a produção de radioisótopos gasosos em reatores nucleares de pesquisa é realizada em pequenas quantidades (bateladas), por meio de ampolas de quartzo contendo o gás natural 40Ar ou 78Kr. Nesse sentido, o objetivo desse estudo é desenvolver um sistema de irradiação capaz de produzir em escala contínua, o radioisótopo gasoso 41Ar, dentre outros, com atividade de 7,4x1011 Bq (20 Ci) por ciclo de irradiação, por meio do Reator IEA-R1 de 4,5 MW, fluxo de nêutrons térmicos médio de 4,71 x 1013 ncm-2s-1, para suprir uma demanda existente em empresas de END e inspeções, e pelo próprio Centro de Tecnologia das Radiações, no IPEN/CNEN-SP. O sistema de irradiação (SI) é constituído por uma cápsula de irradiação em alumínio, linhas de transferência, válvulas agulhas, conexões anilhadas, conectores rápidos, manovacuômetro, sistema de vácuo, dewar de liquefação, blindagem em chumbo, cilindros de armazenamento e transporte (CAT), dentre outros. O SI foi aprovado nos testes de estanqueidade e estabilidade (testes de formação de bolhas, pressurização, evacuação e com equipamento leak detector SPECTRON 600 T). Na produção experimental para obtenção de 1,07x1011 Bq (2,9 Ci) de 41Ar, distribuíram-se dosímetros de alanina em diversos componentes e dispositivos do SI. Além disso, determinaram-se as taxas de exposição na parede da blindagem em chumbo, ao concentrar o gás radioativo liquefeito e no CAT, após a transferência do 41Ar, pelo medidor de radiação portátil Teletector ® Probe 6150 AD-t/H. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

L'Electrolyse de la Vapeur d'eau à Haute Température (EVHT) est l'un des procédésde production d'hydrogène les plus prometteurs. Dans l'optique d'une économie del'hydrogène produit par EVHT, de nombreux verrous restent à lever. L'un d'entre euxporte sur l'étanchéité. En effet, dans un EVHT, la gestion des gaz est primordiale. Ilfaut pouvoir gérer et prévoir dans le temps le comportement des joints afin d'éviter unedégradation des performances. Or, en EVHT, les températures de fonctionnement sontélevées (classiquement autour de 800 °C), des phénomènes de fluage ou de relaxationapparaissent, le différentiel de dilatation thermique entre les cellules électrochimiques encéramique et les interconnecteurs métalliques doit être pris en compte. Enfin, il convientde maintenir l'étanchéité de l'empilement à faible niveau d'effort pour ne pas risquerd'endommager la partie céramique.L'objet du travail de cette thèse démarre par un constat simple : nous ne disposons pasd'outils de prédimensionnement des joints à haute température permettant de prévoirun débit de fuite. Dès lors que l'on est amené à changer un paramètre de fonctionnement,comme la température, la pression, la stratégie de chargement, la géométrie ou la naturedu joint, une nouvelle expérience doit être menée.A partir d'essais d'étanchéité et de simulations numériques aux éléments finis, un modèleoriginal est proposé. Ce modèle qui a été validé en fonction de différents paramètresexpérimentaux permet d'estimer le débit de fuite associé à un joint en Fecralloy (Fe-CrAl) selon sa forme, ses conditions de serrage et du temps de maintien. Offrant ainsila possibilité de concevoir à moindre coût des joints spécifiques pour l'application visée. / High Temperature Steam Electrolysis (HTSE), is one of the most promising processfor hydrogen production. In a hydrogen economy produced via HTSE, many problemshave to be overcome. One of them is related to sealing. Actually, in a HTSE, gasmanagement is very important. The behavior of the seal has to be predicted in time toavoid a deterioration of the performances. But, in a HTSE, the fuctioning temperaturesare important (typically around 800 °C), creep or relaxation may occur, the differencebetween the thermal expansion of the ceramic cells and the metallic interconnectorsmust be taken into account. Finally, the sealing has to be maintain with low effortsprotect the ceramic.This thesis started from the noticing that we don't have any designing tool for hightemperature seals that may help to foresee a leak rate. Since we have to change anyexperimental parameter, such as the temperature, the pressure, the loading strategy, thegeometry or the material of the seal, another experiment has to be done.From sealing tests and finite element modelisation, an original model is presented.This model that has been validated for different experimental parameters allows toestimate the leak rate of a Fecralloy (FeCrAl) seal depending on its shape, the loadingconditions and tightening time. This may help to design specific low cost seals for thedesired applications.

Early administration of broad-spectrum antibiotics is the first goal in sepsis treatment. Besides from bacteriostatic/bactericidal effects, some antibiotics may also modify the host´s response to infection. The novel antibiotic tigecycline may exert such properties; however, this property has not been evaluated in large-animal trials. We compared tigecycline with doxycycline and placebo in relation to anti-inflammatory, circulatory and organ dysfunction effects in a sterile pig model of sepsis. Doxycycline, but not tigecycline, reduced the inflammatory response as manifested by tumor necrosis factor alpha levels in plasma. Tigecycline, however, had a stabilizing effect on the circulation not exerted by doxycycline or placebo. To achieve rapid restoration of the circulating blood volume - another major goal in sepsis treatment - fluid bolus administration of is some-times practiced. In addition to crystalloids, albumin-containing solutions are suggested. Yet, some animal-experimental data suggests that rapid bolus administration of albumin reduces albumin’s plasma-expanding effect. We compared a rapid intravenous bolus of radiolabeled albumin with a slow infusion in a sterile pig model of sepsis. Rapid bolus of administration did not reduce plasma levels of albumin following administration and did not increase the amount of albumin that left the circulation. Inadequate oxygen delivery (DO2) by the circulation to the tissues may cause increased plasma lactate, which is the most striking effect of sepsis on the metabolism. However, experimental data and clinical trials refute this link, instead, suggesting other mechanisms, including impaired oxygen extraction, mitochondrial dysfunction and accelerated aerobic glycolysis. We investigated the impact of DO2, oxygen consumption (VO2), hemodynamic parameters and inflammatory response on plasma lactate and organ dysfunction in two experimental sepsis models. In the most severe cases of shock, with DO2, there was an increase in plasma lactate, but without a decrease in VO2, invalidating the assumption that the increase in lactate is due to anaerobic metabolism. To identify critical steps in the sepsis-induced increase in lactate, we inhibited the major energy-producing step in the electron transport chain (ETC). The combination of sepsis and ETC inhibition led to a cellular energy crisis. This finding suggests that early sepsis induces a partial mitochondrial dysfunction.

As the world transitions to intermittent renewable energy sources like solar and wind, the need for long-duration energy storage technologies is becoming more and more prominent. In this regard, flow batteries are seen as a promising solution, owing to their inherent advantages like decoupling of power and energy, extremely high cycle life and negligible self-discharge. However, there are multiple engineering challenges to overcome before the widespread application of flow batteries.   This study, carried out at a leading manufacturer of vanadium-based flow batteries, VoltStorage GmbH, addresses one of those challenges related to the hydraulic sealing of the endplate assembly of the battery. The endplate assembly is prone to losing its structural integrity over the continuous operation, thus failing to achieve its intended purpose of hydraulic sealing. Additionally, it is susceptible to enhanced contact resistance during operation, thus harming the battery performance. Therefore, the primary objective of this study was to develop a modular test rig that could evaluate the endplate assembly's performance in an accelerated manner but without using electrolytes to eliminate the complications of dealing with the sulfuric acid solution (i.e. electrolyte). So, air was chosen as the working fluid to offer clean and highly repeatable testing.   The study began with a literature review of the flow batteries. It was found that the literature concerning the engineering aspects of a flow battery was limited. Therefore, it was followed by an in-depth analysis of the stack design of VoltStorage and the engineering challenges linked to the endplate assembly. Importantly, the root cause of the problem of hydraulic sealing was identified, which was the pressure cycling of the monopole. After that, the test rig was designed and developed based on the understanding of the engineering challenge and to realize the objective of a modular design. The design modularity was desirable to test multiple assemblies simultaneously without increasing the floor footprint. Three parameters were chosen to characterize the assembly: monopole deflection, internal resistance and air leak rate. Due to the system's complexity, experiments to monitor these parameters were divided into two phases, i.e., rig qualification and full-scale testing. The first phase aimed to characterize their baseline behaviour and evaluate the rig's robustness; the next phase aimed at monitoring their behaviour evolution with continuous operation.   The monopole deflection measurements during the first phase indicated a maximum deflection of 0.3 mm. The air-electrolyte equivalence was also established by making the deflection behaviour similar during air and electrolyte operation. Much higher pressure had to be applied with air (~1.6 bar gauge) than water (~0.8 bar gauge) to achieve this equivalence. Moreover, the internal resistance and air leak rate measurements conducted during the first phase provided baseline values (6.341 ± 0.731 mΩ and 1.241 ± 0.091 Pa∙l/s, respectively, with a 95% confidence level) against which any change during continuous operation could be differentiated. However, the full-scale testing could not be performed due to the global supply chain disruptions and the limited time frame of the project. Nevertheless, a vital objective of the design, to modularize the rig so that it could be scaled up quickly and test multiple assemblies simultaneously to facilitate the rapid prototyping of different designs, was realized in the project.   Flow batteries are a promising technology for long-duration energy storage, although there are some challenges to overcome. In addition, to be defined as a truly sustainable solution, the problems linked with vanadium mining and the high capital costs of the system have to be eliminated. With the rapidly expanding development and deployment of these systems, it is expected that they will be an essential part of our future grids.   To conclude, in this project, a testing system was developed which could perform a dry mechanical and electrical integrity check of the endplate assembly of a flow battery in an accelerated manner. The system could prove to be vital in enhancing the reliability of stack-based systems and hence foster their widespread applicability. The future work that can benefit this system is assembling the set of 5 short stacks and performing a continuous operation to monitor the behaviour evolution of the stacks. This step would help assess the testing system's shortcomings and subsequently make the required modifications. / I takt med att världen övergår till intermittenta förnybara energikällor som sol- och vindkraft blir behovet av teknik för energilagring med lång varaktighet alltmer framträdande. Flödesbatterier ses i detta avseende som en lovande lösning på grund av deras inneboende fördelar, t.ex. frikoppling av kraft och energi, extremt lång livslängd och försumbar självurladdning. Det finns dock flera tekniska utmaningar som måste övervinnas innan flödesbatterier kan användas på bred front.  Den här studien, som utfördes hos VoltStorage GmbH, en ledande tillverkare av vanadiumbaserade flödesbatterier, tar upp en av dessa utmaningar som rör den hydrauliska tätningen av batteriets ändplatta. Ändtplattan är benägen att förlora sin strukturella integritet under kontinuerlig drift, vilket innebär att den inte uppnår sitt avsedda syfte, nämligen hydraulisk tätning. Dessutom är den känslig för ökat kontaktmotstånd under drift, vilket skadar batteriets prestanda. Det primära målet med denna studie var därför att utveckla en modulär testrigg som kan utvärdera ändplattans prestanda på ett påskyndat sätt, men utan att använda elektrolyter för att eliminera komplikationerna med att hantera svavelsyralösningen (dvs. elektrolyten). Därför valdes luft som arbetsvätska för att erbjuda rena och mycket repeterbara tester.   Studien inleddes med en litteraturgenomgång av flödesbatterier. Det konstaterades att litteraturen om de tekniska aspekterna av ett flödesbatteri var begränsad. Därför följdes den av en djupgående analys av VoltStorages stapelkonstruktion och de tekniska utmaningarna i samband med ändplattans montering. Det var viktigt att identifiera grundorsaken till problemet med hydraulisk tätning, vilket var tryckcykling av monopolen. Därefter utformades och utvecklades testriggen utifrån förståelsen av den tekniska utmaningen och för att förverkliga målet med en modulär konstruktion. Modulariteten i konstruktionen var önskvärd för att testa flera enheter samtidigt utan att öka golvytan. Tre parametrar valdes ut för att karakterisera enheten: monopolens avböjning, inre motstånd och luftläckagehastighet. På grund av systemets komplexitet delades experimenten för att övervaka dessa parametrar upp i två faser, dvs. kvalificering av riggen och provning i full skala. Den första fasen syftade till att karakterisera deras grundbeteende och utvärdera riggens robusthet, medan nästa fas syftade till att övervaka deras funktionella respons utveckling vid kontinuerlig drift.   Mätningarna av monopolens nedböjning under den första fasen visade på en maximal nedböjning på 0,3 mm. Likvärdigheten mellan luft och elektrolyt fastställdes också genom att utböjningsbeteendet var likartat under drift med luft och elektrolyt. Ett mycket högre tryck måste tillämpas med luft (~1,6 bar gauge) än med vatten (~0,8 bar gauge) för att uppnå denna likvärdighet. Dessutom gav de mätningar av det inre motståndet och luftläckaget som utfördes under den första fasen basvärden (6,341 ± 0,731 mΩ respektive 1,241 ± 0,091 Pa∙l/s, med en konfidensnivå på 95 %) mot vilka eventuella förändringar under kontinuerlig drift kunde särskiljas. Den fullskaliga testningen kunde dock inte genomföras på grund av störningar i den globala leveranskedjan och projektets begränsade tidsram. Ett viktigt mål med konstruktionen, att modularisera riggen så att den snabbt kan skalas upp och testa flera enheter samtidigt för att underlätta snabb prototypframställning av olika konstruktioner, förverkligades dock i projektet.  Flödesbatterier är en lovande teknik för energilagring under lång tid, även om det finns vissa utmaningar att övervinna. För att kunna definieras som en verkligt hållbar lösning måste dessutom de problem som är kopplade till vanadinbrytning och systemets höga kapitalkostnader undanröjas. Med den snabbt ökande utvecklingen och spridningen av dessa system förväntas de bli en viktig del av våra framtida nät.   Sammanfattningsvis utvecklades i detta projekt ett testsystem som kan utföra en torr mekanisk och elektrisk integritetskontroll av ändplattan i ett flödesbatteri på ett påskyndat sätt. Systemet kan visa sig vara avgörande för att öka tillförlitligheten hos stapelbaserade system och därmed främja deras utbredda användbarhet. Det framtida arbete som kan gynna detta system är att montera en uppsättning av fem korta staplar och utföra en kontinuerlig operation för att övervaka staplarnas funktionella responsutveckling. Detta steg skulle hjälpa till att bedöma testsystemets brister och därefter göra de ändringar som krävs.

Three testing methods are proposed to characterize properties of fuel cell materials that affect the mechanical durability of proton exchange membranes (PEMs). The first two methods involved measuring the in-plane biaxial strength of PEMs and the biaxial hygrothermal stresses that occur in PEMs during hygrothermal cycles. The third method investigated the nonuniform thickness and compressibility of gas diffusion media which can lead to concentrated compressive stresses in the PEM in the through-plane direction. Fatigue and creep to leak tests using multi-cell pressure-loaded blister fixtures were conducted to obtain the lifetimes of PEMs before reaching a threshold value of gas leakage. These tests are believed to be more relevant than quasi-static uniaxial tensile to rupture tests because of the introduction of biaxial cyclic and sustained loading and the use of gas leakage as the failure criterion. They also have advantages over relative humidity cycling test because of the controllable mechanical loading. Nafion® NRE-211 membrane was tested at three different temperatures and the time-temperature superposition principle was used to construct a stress-lifetime master curve. Tested at 90°C, extruded Ion Power® N111-IP membrane was found to have longer lifetime than Gore™-Select® 57 and Nafion NRE-211 membranes under the same blister pressure profiles. Bimaterial specimens fabricated by bonding a piece of PEM to a substrate material were used to measure the hygral stresses, compressive and tensile, in the PEM during relative humidity cycles. The substrate material and its thickness were carefully chosen so that stresses in the PEM could be obtained directly from the curvature of the bimaterial specimen without knowing the constitutive properties of the PEM. Three commercial PEMs were tested at 80°C by cycling the relative humidity between 90% and 0% and by drying the membrane to 0%RH after submersion in liquid water. Stress histories for all three membranes show strong time-dependencies and Nafion® NRE-211 exhibited the largest tensile stress upon drying. Besides in-plane stresses, hard spots in gas diffusion media (GDM) can locally overcompress PEMs in the out-of-plane direction and cause electrical shorting. In this study, GDM samples sealed with an impermeable Kapton® film on the surface were compressed with uniform air pressure and the nonuniform displacement field was measured with a three-dimensional digital image correlation technique. Hard spots as a result of the nonuniform thickness and compressibility of the GDM were found and their severities as stress risers are evident. Locally, a nominal platen compression (similar to bipolar plate land compression) of 0.68 MPa can lead to compressive stress as large as 2.30 MPa in various hard spots that are in the order of 100s µm to 1 mm in size. / Ph. D.