CHARACTERIZATION AND THERMAL-HYDRAULIC MODELING OF ENGINEERED BARRIERS FOR A CANADIAN DEEP GEOLOGICAL REPOSITORY FOR USED NUCLEAR FUEL

Within Canada there are more than 2.5 million bundles of spent nuclear fuel with another approximately 2 million bundles to be generated in the future. Canada, and every country around the world that has taken a decision on management of spent nuclear fuel, has decided on long-term containment and isolation of the fuel within a deep geological repository. At depth, a deep geological repository consists of a network of placement rooms where the bundles will be located within a multi-layered system that incorporates engineered and natural barriers. The barriers will be placed in a complex thermal-hydraulic-mechanical-chemical-biological (THMCB) environment. A large database of material properties for all components in the repository are required to construct representative models. Within the repository, the sealing materials will experience elevated temperatures due to the thermal gradient produced by radioactive decay heat from the waste inside the container. Furthermore, high porewater pressure due to the depth of repository along with possibility of elevated salinity of groundwater would cause the bentonite-based materials to be under transient hydraulic conditions. Therefore it is crucial to characterize the sealing materials over a wide range of thermal-hydraulic conditions. A comprehensive experimental program has been conducted to measure properties (mainly focused on thermal properties) of all sealing materials involved in Mark II concept at plausible thermal-hydraulic conditions. The thermal response of Canada’s concept for a deep geological repository has been modelled using experimentally measured thermal properties. Plausible scenarios are defined and the effects of these scenarios are examined on the container surface temperature as well as the surrounding geosphere to assess whether they meet design criteria for the cases studied. The thermal response shows that if all the materials even being at dried condition, repository still performs acceptably as long as sealing materials remain in contact.

Sweat Lodges in Iron Age Iberian Peninsula: New Data, Typologies and Interpretations

Three questions on the study of NO Iberian Peninsula sweat lodges are posed. First, the new sauna of Monte Ornedo (Cantabria), the review of the one of Armea (Ourense), and the Cantabrian pedra formosa type are discussed. Second, the known types of sweat lodges are reconsidered underlining the differences between the Cantabrian and the Douro - Minho groups as these differences contribute to a better assessment of the saunas located out of those territories, such as those of Monte Ornedo or Ulaca. Third, a richer record demands a more specific terminology, a larger use of archaeometric analysis and the application of landscape archaeology or art history methodologies. In this way the range of interpretation of the sweat lodges is opened, as an example an essay is proposed that digs on some already known proposals and suggests that the saunas are material metaphors of wombs whose rationale derives from ideologies and ritual practices of Indo-European tradition.

Optimal location of solid waste containers in Alcalá de Henares

The waste’s rise is a problem that affects the environment as a whole and we cannot forget about it. A good waste’s management is the key to improve the future prospect, and the waste collection is key within the management activities. To find out the better way to collect wastes leads to a reduction of the social, economic and environmental cost. With the use of the Geographic Information Systems it has been intended to elaborate a methodology which allowed us to identify the most suitable places for the location of the collection containers of the different sorts of the solid urban wastes. Taking into account that different types of wastes exist, not all of them should be managed in the same way. Therefore we have to differentiate between models where we apply efficiency and models where we apply equity for the collection of wastes, bearing in mind the necessities of each waste.

Free-stretch-blow Investigation of Poly(ethylene terephthalate) over a Large Process Window

This paper highlights for the first time a full comprehension of the deformation procedure during the injection stretch blow moulding (ISBM) process of poly(ethylene terephthalate) (PET) containers, namely thin-walled rigid bottles. The processes required to form PET bottles are complicated and extensive; any development in understanding the nature of material deformation can potentially improve the bottle optimisation process. Removing the bottle mould and performing free-stretch-blow (FSB) experiments revealed insight into the bottle forming characteristics at various preform temperatures and blowing rates. Process outputs cavity pressure and stretch-rod force were recorded using at instrumented stretch-rod and preform surface strain mapping was determined using a combination of a unique patterning procedure and high speed stereoscopic digital image correlation. The unprecedented experimental analysis reveals that the deformation behaviour varies considerably with contrasting process input parameters. Investigation into the effect on deformation mode, strain rate and final bottle shape provide a basis for full understanding of the process optimisation and therefore how the process inputs may aid development of the preferred optimised container.

Flexible Automatisierung logistischer Prozesse durch modulare Roboter

Die Automatisierung logistischer Prozesse stellt aufgrund dynamischer Prozesseigenschaften und wirtschaftlicher Anforderungen eine große technische Herausforderung dar. Es besteht der Bedarf nach neuartigen hochflexiblen Automatisierungs- und Roboterlösungen, die in der Lage sind, variable Güter zu handhaben oder verschiedene Prozesse bzw. Funktionalitäten auszuführen. Im Rahmen dieses Beitrages wird die Steigerung der Flexibilität anhand von zwei konkreten Beispielen aus den Bereichen Stückguthandhabung und Materialflusstechnik adressiert.

Analisi del ruolo del porto di Ravenna nell’import/export di prodotti ortofrutticoli

L'elaborato tratta il ruolo del porto di Ravenna nell'import/export di prodotti ortofrutticoli. Dopo una accurata analisi dei dati, lo studio delle rotte marittime e l'uso di Dbms per gestire un database complesso, si propone un modello di programmazione lineare intera su un problema di ship routing, ship scheduling e full ship-load balancing. L'obiettivo è di massimizzare il profitto derivante da un prezzo di vendita e soggetto ai vari costi della logistica. Il modello sceglie la rotta ottimale da effettuare, in termini di ordine di visita dei vari porti che hanno un import e un export dei prodotti studiati. Inoltre, è in grado di gestire lo scorrere del tempo, fornendo come soluzione il giorno ottimale di visita dei vari porti considerati. Infine, trova la ripartizione ottima del numero di container a bordo della nave per ogni tipologia di prodotto.

Challenges Facing Long Term Foster Carers: Exploration of the Nature of Psychoanalytic Parent/Carer Support

This research study investigates the role and impact of psychoanalytically-informed short-term parent work with long-term foster carers of looked-after children, in support of the foster placement. The study reflects on the data gathered from four child assessments and five foster families seen by a psychoanalytic child psychotherapist for four sessions each. It draws on psychoanalytic ideas from a range of theoretical traditions, exploring such concepts as trauma, defences, compulsion to repeat, psychological-mindedness, ‘container/contained’ (Bion) and ‘holding environment’ (Winnicott). One distinctive contribution of this research is what it adds to our already existing understanding of the defences (or responses) aroused in the carer when faced with the intense and distressing affect associated with the child’s early trauma; and the impact of this legacy of trauma on the child, on the carer and on the wider Social Services system. Applying Grounded Theory and psychoanalytically-informed clinical case study methodology to the research material, the study breaks down the data analysis into seven stages of coding, from the initial reading of the data to the eventual development of two key hypotheses. One of the predominant themes that emerged from the analysis was the carer’s capacity to remain focused on the child’s emotional needs and how this in turn was linked to the direction of the therapist’s focus. The successive analyses of the data culminated in the hypothesis that the more the therapist focused on the carer and the carer’s emotional states in the course of the parent work, the more the carer was enabled to focus on the child’s emotional needs. As the system of categories emerged according to the themes exemplified in the sessions, a particular focus of analysis became the concept of psychologicalmindedness, considered under several sub-categories: displaying insightful comments; awareness of the child’s bodily states; awareness of the child’s affect; the carer’s ability to recognize the child’s defences; and the carer’s ability to make links between the child’s current difficulties and the child’s past experiences. Through this analysis it became apparent that degree of psychological-mindedness was closely linked to the individual carer’s capacity to metabolize the child’s distressed and distressing communication. This in turn led to a deeper exploration of the situations that were particularly challenging for the carers: i.e., instances when the child was compelled to repeat past traumatic emotional states and as a result was communicating intense distress. This exploration eventually generated the second hypothesis: that in reaction to the child’s distress, the response of each carer could be plotted somewhere along a spectrum, from either distancing themselves from the child’s emotional state to seeking excessive closeness with the child (merging). The next stage of the analysis developed four new categories of carer responses to the distressed child: identification and distancing from the child; identification and merging with the child; the category that describes the carer’s psychologicalmindedness as being ‘impaired’; and ‘good enough’ caring. This then led to an exploration of the carer’s own defences at these most challenging times. This research demonstrates clearly that even within the short space of four sessions of weekly psychoanalytic parent work, it is possible to achieve significant improvement in a carer’s capacity to bear the child’s compulsion to repeat early traumas, and to help the carers become more emotionally available to provide the child with effective psychological parenting at such difficult and challenging times. Key words: looked-after children; long-term foster carers; psychoanalytic short-term parent work; trauma; compulsion to repeat; psychological-mindedness; empathy; defences; psychoanalytically-informed clinical case study research methodology; Grounded Theory research methodology.

Live Work: The Impact of Direct Encounters in Statutory Child and Family Social Wor

The aim of this research project was to examine the impact of direct work on practitioners in the field of statutory child protection. The author’s premise was that this work was anything but straightforward and that surprisingly, given the intense scrutiny on Children’s Services following a child death, there was little research into the day-to-day practice of front line staff. The aim was to explore whether psychoanalytic theory could be useful in understanding and making sense of the social work task. Data was collected through observation and semi-structured interviews in one Local Authority Child in Need team over a period of six months. The findings indicated that practitioners experienced direct work with some individuals and families as profoundly disturbing and that this affected them physiologically as well as psychologically. These effects persisted over time and appeared very difficult for the workers to process or articulate. This could be expressed through embodied or non-verbal communication in the interview. Practitioners appeared to be ‘inhabited’ by particular clients, suggesting phenomena such as projective identification were in operation. The intensity and persistence of the impact on the practitioners appears to be directly related to the quality, nature and intensity of the psychic defences functioning for the particular client. Significantly, the research indicated that when practitioners were dealing with the negative and disturbing projections from the (adult) clients it seemed from the data that the focus on the child would slip so that the child appeared to recede from view. Symptoms experienced by the practitioners were akin to trauma and research and theory on primary and secondary trauma were considered. Other issues raised included shame, which affects the clients, practitioners and the organisation and the meaning and implications of this are explored. Links between neuroscience and projective identification are addressed as well as the role of the organisation, particularly as a container for these toxic and disturbing encounters.

A Mobile High Sensitivity On-field Organophosphorous Compounds Detecting System for IoT Based Food Safety Tracking

Food safety has always been a social issue that draws great public attention. With the rapid development of wireless communication technologies and intelligent devices, more and more Internet of Things (IoT) systems are applied in the food safety tracking field. However, connection between things and information system is usually established by pre-storing information of things into RFID Tag, which is inapplicable for on-field food safety detection. Therefore, considering pesticide residue is one of the severe threaten to food safety, a new portable, high-sensitivity, low-power, on-field organophosphorus (OP) compounds detection system is proposed in this thesis to realize the on-field food safety detection. The system is designed based on optical detection method by using a customized photo-detection sensor. A Micro Controller Unit (MCU) and a Bluetooth Low Energy (BLE) module are used to quantize and transmit detection result. An Android Application (APP) is also developed for the system to processing and display detection result as well as control the detection process. Besides, a quartzose sample container and black system box are also designed and made for the system demonstration. Several optimizations are made in wireless communication, circuit layout, Android APP and industrial design to realize the mobility, low power and intelligence.

As vozes testemunhais em Longe de Manaus

A presente dissertação consiste na análise do romance Longe de Manaus, de Francisco José Viegas, publicado em 2005, em Portugal. O trabalho tem como objetivo responder ao questionamento de quais são as funções dos testemunhos na refiguração do tempo e na narração do passado? No âmbito teórico, analisa os atos de testemunhar e narrar associados ao conceito de memória e à ideia de distância a partir das abordagens de Paul Ricoeur e das contribuições de Carlo Guinzburg, de modo a relacionar a tradição do olhar interior com o exterior. Nos dois casos, a leitura de Agostinho se faz presente, pois o filósofo inaugura a memória como um produto da linguagem e preconiza a busca dos vestígios nos fenômenos mnemônicos. O contexto de produção é introduzido com as proposições de Eduardo Lourenço sobre a identidade nacional portuguesa, com a definição de sul proposta por Boaventura de Souza Santos e pelas colocações de Edgar Morin acerca do marxismo na atualidade, além de retomar a conjuntura da década de 1970 tendo em vista as pesquisas dos historiadores Eric Hobsbawn e Majhemout Diop, que estudaram o neocolonialismo. No âmbito analítico, é interpretada a organização cíclica do romance que entrecruza personagens e vozes narrativas de espaços e temporalidades diferentes, com a finalidade de abordar como a pobreza e a violência podem ser fatores constantes na África da década de 1970, sob o domínio imperial lusitano, ou nas cidades do Porto, São Paulo e Manaus contemporâneas. O narrador apresenta problemas sociais em Portugal, nos anos 2000, atrelados às politicas econômicas e à entrada de imigrantes do sul; concomitantemente, o protagonista Jaime Ramos debate a sua sociedade a partir de dois critérios: o de identidade nacional portuguesa, segundo o critério levantado por ele de solidão, e o de defesa da luta de classes como fator primordial para compreender os assassinatos investigados pela personagem. O estudo articula as noções de memória e literatura com a finalidade de analisar as estratégias narrativas presentes em Longe de Manaus.

Identidades diaspóricas e memória em A luz do Índico, de Francisco José Viegas

O objetivo do presente estudo é verificar como ocorre a representação da diáspora portuguesa no romance A luz do Índico, de Francisco José Viegas, pautando-se na análise de quatro elementos fundamentais nessa narrativa: o retorno, a busca, a identidade e a memória. Deseja-se, assim, identificar a relação do deslocamento físico e do sentimento de exílio com as questões de pertencimento e identidade, bem como apresentar o contraste entre a memória do colonizador e a do colonizado. De igual forma, pretende-se estabelecer conexões entre história, memória e literatura, com ênfase nas especificidades do colonialismo português e como elas se refletem no âmbito da pós-colonialidade.

Functional alkali tantalate 2D structures for microelectronics and related applications

Alkali tantalates and niobates, including K(Ta / Nb)O3, Li(Ta / Nb)O3 and Na(Ta / Nb)O3, are a very promising ferroic family of lead-free compounds with perovskite-like structures. Their versatile properties make them potentially interesting for current and future application in microelectronics, photocatalysis, energy and biomedics. Among them potassium tantalate, KTaO3 (KTO), has been raising interest as an alternative for the well-known strontium titanate, SrTiO3 (STO). KTO is a perovskite oxide with a quantum paraelectric behaviour when electrically stimulated and a highly polarizable lattice, giving opportunity to tailor its properties via external or internal stimuli. However problems related with the fabrication of either bulk or 2D nanostructures makes KTO not yet a viable alternative to STO. Within this context and to contribute scientifically to the leverage tantalate based compounds applications, the main goals of this thesis are: i) to produce and characterise thin films of alkali tantalates by chemical solution deposition on rigid Si based substrates, at reduced temperatures to be compatible with Si technology, ii) to fulfil scientific knowledge gaps in these relevant functional materials related to their energetics and ii) to exploit alternative applications for alkali tantalates, as photocatalysis. In what concerns the synthesis attention was given to the understanding of the phase formation in potassium tantalate synthesized via distinct routes, to control the crystallization of desired perovskite structure and to avoid low temperature pyrochlore or K-deficient phases. The phase formation process in alkali tantalates is far from being deeply analysed, as in the case of Pb-containing perovskites, therefore the work was initially focused on the process-phase relationship to identify the driving forces responsible to regulate the synthesis. Comparison of phase formation paths in conventional solid-state reaction and sol-gel method was conducted. The structural analyses revealed that intermediate pyrochlore K2Ta2O6 structure is not formed at any stage of the reaction using conventional solid-state reaction. On the other hand in the solution based processes, as alkoxide-based route, the crystallization of the perovskite occurs through the intermediate pyrochlore phase; at low temperatures pyrochlore is dominant and it is transformed to perovskite at >800 °C. The kinetic analysis carried out by using Johnson-MehlAvrami-Kolmogorow model and quantitative X-ray diffraction (XRD) demonstrated that in sol-gel derived powders the crystallization occurs in two stages: i) at early stage of the reaction dominated by primary nucleation, the mechanism is phase-boundary controlled, and ii) at the second stage the low value of Avrami exponent, n ~ 0.3, does not follow any reported category, thus not permitting an easy identification of the mechanism. Then, in collaboration with Prof. Alexandra Navrotsky group from the University of California at Davis (USA), thermodynamic studies were conducted, using high temperature oxide melt solution calorimetry. The enthalpies of formation of three structures: pyrochlore, perovskite and tetragonal tungsten bronze K6Ta10.8O30 (TTB) were calculated. The enthalpies of formation from corresponding oxides, ∆Hfox, for KTaO3, KTa2.2O6 and K6Ta10.8O30 are -203.63 ± 2.84 kJ/mol, - 358.02 ± 3.74 kJ/mol, and -1252.34 ± 10.10 kJ/mol, respectively, whereas from elements, ∆Hfel, for KTaO3, KTa2.2O6 and K6Ta10.8O30 are -1408.96 ± 3.73 kJ/mol, -2790.82 ± 6.06 kJ/mol, and -13393.04 ± 31.15 kJ/mol, respectively. The possible decomposition reactions of K-deficient KTa2.2O6 pyrochlore to KTaO3 perovskite and Ta2O5 (reaction 1) or to TTB K6Ta10.8O30 and Ta2O5 (reaction 2) were proposed, and the enthalpies were calculated to be 308.79 ± 4.41 kJ/mol and 895.79 ± 8.64 kJ/mol for reaction 1 and reaction 2, respectively. The reactions are strongly endothermic, indicating that these decompositions are energetically unfavourable, since it is unlikely that any entropy term could override such a large positive enthalpy. The energetic studies prove that pyrochlore is energetically more stable phase than perovskite at low temperature. Thus, the local order of the amorphous precipitates drives the crystallization into the most favourable structure that is the pyrochlore one with similar local organization; the distance between nearest neighbours in the amorphous or short-range ordered phase is very close to that in pyrochlore. Taking into account the stoichiometric deviation in KTO system, the selection of the most appropriate fabrication / deposition technique in thin films technology is a key issue, especially concerning complex ferroelectric oxides. Chemical solution deposition has been widely reported as a processing method to growth KTO thin films, but classical alkoxide route allows to crystallize perovskite phase at temperatures >800 °C, while the temperature endurance of platinized Si wafers is ~700 °C. Therefore, alternative diol-based routes, with distinct potassium carboxylate precursors, was developed aiming to stabilize the precursor solution, to avoid using toxic solvents and to decrease the crystallization temperature of the perovskite phase. Studies on powders revealed that in the case of KTOac (solution based on potassium acetate), a mixture of perovskite and pyrochlore phases is detected at temperature as low as 450 °C, and gradual transformation into monophasic perovskite structure occurs as temperature increases up to 750 °C, however the desired monophasic KTaO3 perovskite phase is not achieved. In the case of KTOacac (solution with potassium acetylacetonate), a broad peak is detected at temperatures <650 °C, characteristic of amorphous structures, while at higher temperatures diffraction lines from pyrochlore and perovskite phases are visible and a monophasic perovskite KTaO3 is formed at >700 °C. Infrared analysis indicated that the differences are due to a strong deformation of the carbonate-based structures upon heating. A series of thin films of alkali tantalates were spin-coated onto Si-based substrates using diol-based routes. Interestingly, monophasic perovskite KTaO3 films deposited using KTOacac solution were obtained at temperature as low as 650 °C; films were annealed in rapid thermal furnace in oxygen atmosphere for 5 min with heating rate 30 °C/sec. Other compositions of the tantalum based system as LiTaO3 (LTO) and NaTaO3 (NTO), were successfully derived as well, onto Si substrates at 650 °C as well. The ferroelectric character of LTO at room temperature was proved. Some of dielectric properties of KTO could not be measured in parallel capacitor configuration due to either substrate-film or filmelectrode interfaces. Thus, further studies have to be conducted to overcome this issue. Application-oriented studies have also been conducted; two case studies: i) photocatalytic activity of alkali tantalates and niobates for decomposition of pollutant, and ii) bioactivity of alkali tantalate ferroelectric films as functional coatings for bone regeneration. Much attention has been recently paid to develop new type of photocatalytic materials, and tantalum and niobium oxide based compositions have demonstrated to be active photocatalysts for water splitting due to high potential of the conduction bands. Thus, various powders of alkali tantalates and niobates families were tested as catalysts for methylene blue degradation. Results showed promising activities for some of the tested compounds, and KNbO3 is the most active among them, reaching over 50 % degradation of the dye after 7 h under UVA exposure. However further modifications of powders can improve the performance. In the context of bone regeneration, it is important to have platforms that with appropriate stimuli can support the attachment and direct the growth, proliferation and differentiation of the cells. In lieu of this here we exploited an alternative strategy for bone implants or repairs, based on charged mediating signals for bone regeneration. This strategy includes coating metallic 316L-type stainless steel (316L-SST) substrates with charged, functionalized via electrical charging or UV-light irradiation, ferroelectric LiTaO3 layers. It was demonstrated that the formation of surface calcium phosphates and protein adsorption is considerably enhanced for 316L-SST functionalized ferroelectric coatings. Our approach can be viewed as a set of guidelines for the development of platforms electrically functionalized that can stimulate tissue regeneration promoting direct integration of the implant in the host tissue by bone ingrowth and, hence contributing ultimately to reduce implant failure.

Otimização da recolha de resíduos urbanos : caso de estudo de Aveiro

O elevado custo da operação de recolha de resíduos urbanos e a necessidade de cumprir metas dispostas em instrumentos legais são duas motivações que conduzem à necessidade de otimizar o serviço da recolha de resíduos. A otimização da recolha de resíduos é um problema de elevada complexidade de resolução que envolve a análise de redes de transporte. O presente trabalho propõe soluções de otimização da recolha de resíduos urbanos indiferenciados, a partir de um caso de estudo: o percurso RSU I 06 do município de Aveiro. Para este efeito, recorreu-se a uma aplicação informática de representação e análise geográfica: software ArcGIS denominada ArcMap e sua extensão Network Analyst, desenvolvida para calcular circuitos otimizados entre pontos de interesse. O trabalho realizado de aplicação do Network Analyst inclui a apresentação de duas das suas funcionalidades (Route e Vehicle Routing Problem). Em relação ao atual circuito de recolha e com base nos ensaios efetuados, foi possível concluir que esta aplicação permite obter circuitos de recolha otimizados mais curtos ou com menor duração. Contudo, ao nível da gestão permitiu concluir que, com a atual capacidade de contentorização, seria viável reduzir a frequência de recolha de seis vezes por semana para metade, dividindo a área de recolha em duas áreas, de acordo com as necessidades de cada local, reduzindo ainda mais o esforço de recolha. A aplicação do Network Analyst ao caso de estudo, permitiu concluir que é um software com muito interesse no processo de gestão da recolha de resíduos urbanos, apesar de apresentar algumas restrições de aplicação e que a qualidade/eficácia do procedimento de otimização depende da qualidade dos dados de entrada, em particular do descritivo geográfico disponível para os arruamentos e, em larga medida, também depende do modelo de gestão considerado.

O problema de alocação de berços: um estudo das heurísticas simulated annealing e algoritmo genético

Este trabalho apresenta um estudo de caso das heurísticas Simulated Annealing e Algoritmo Genético para um problema de grande relevância encontrado no sistema portuário, o Problema de Alocação em Berços. Esse problema aborda a programação e a alocação de navios às áreas de atracação ao longo de um cais. A modelagem utilizada nesta pesquisa é apresentada por Mauri (2008) [28] que trata do problema como uma Problema de Roteamento de Veículos com Múltiplas Garagens e sem Janelas de Tempo. Foi desenvolvido um ambiente apropriado para testes de simulação, onde o cenário de análise foi constituido a partir de situações reais encontradas na programação de navios de um terminal de contêineres. Os testes computacionais realizados mostram a performance das heurísticas em relação a função objetivo e o tempo computacional, a m de avaliar qual das técnicas apresenta melhores resultados.

A Binary Classifier for Test Case Feasibility Applied to Automatically Generated Tests of Event-Driven Software

Modern software application testing, such as the testing of software driven by graphical user interfaces (GUIs) or leveraging event-driven architectures in general, requires paying careful attention to context. Model-based testing (MBT) approaches first acquire a model of an application, then use the model to construct test cases covering relevant contexts. A major shortcoming of state-of-the-art automated model-based testing is that many test cases proposed by the model are not actually executable. These \textit{infeasible} test cases threaten the integrity of the entire model-based suite, and any coverage of contexts the suite aims to provide. In this research, I develop and evaluate a novel approach for classifying the feasibility of test cases. I identify a set of pertinent features for the classifier, and develop novel methods for extracting these features from the outputs of MBT tools. I use a supervised logistic regression approach to obtain a model of test case feasibility from a randomly selected training suite of test cases. I evaluate this approach with a set of experiments. The outcomes of this investigation are as follows: I confirm that infeasibility is prevalent in MBT, even for test suites designed to cover a relatively small number of unique contexts. I confirm that the frequency of infeasibility varies widely across applications. I develop and train a binary classifier for feasibility with average overall error, false positive, and false negative rates under 5\%. I find that unique event IDs are key features of the feasibility classifier, while model-specific event types are not. I construct three types of features from the event IDs associated with test cases, and evaluate the relative effectiveness of each within the classifier. To support this study, I also develop a number of tools and infrastructure components for scalable execution of automated jobs, which use state-of-the-art container and continuous integration technologies to enable parallel test execution and the persistence of all experimental artifacts.