Academic literature on the topic 'Jeu vidéo actifs'

Pour lutter contre l’inactivité physique des adolescents, des études ont montré que les jeux vidéo actifs (JVA) multi-joueurs proposant un affrontement entre deux équipes ont un impact (psychologique comme physiologique) supérieur à celui des JVA joués en solitaire. Cet impact a cependant été peu étudié dans le cas des JVA permettant un affrontement entre équipes durant la même session, en raison du faible nombre de dispositifs permettant ce mode de pratique. Le récent dispositif Play Lü® propose justement un mode multi-joueurs avec affrontement simultané de deux ou plusieurs équipes. Cette étude vise à rendre compte des effets d’une session Play Lü (15 min ; affrontement de deux équipes de trois joueurs) sur l’intérêt en situation et le degré d’activité physique de 128 adolescents (69 filles ; Mâge = 13.9±1.2 ans), en les comparant à ceux d’une session contrôle (sans Play Lü) utilisant les mêmes modalités de temps et d’équipes. Les résultats montrent que la session Play Lü a généré un intérêt en situation et une activité physique plus élevée.

L’UER EPS au sein de la HEP Vaud a investi depuis 2019 dans un dispositif de jeux vidéo actifs (JVA), la plateforme Lü® et développe différents travaux de recherche et développement afin de mesurer les effets de ce dispositif sur l’activité physique, la motivation et les apprentissages des élèves. Concernant les apprentissages, un premier projet a consisté à développer une séquence interdisciplinaire en éducation physique et en mathématiques avec et sans le dispositif Lü®. Un second projet en cours de développement vise le développement de séquences interdisciplinaires en éducation physique et en langues. Au regard de leurs caractéristiques intrinsèques, les JVA constituent des ressources pédagogiques intéressantes afin d’améliorer les apprentissages en milieu scolaire. Un travail d’ingénierie didactique est nécessaire afin que les apprentissages soient mis au cœur des séquences et que le jeu devienne un moyen au service des apprentissages.

Le jeu vidéo proposerait une nouvelle forme de subjectivation autour de l’action en mouvement, dont le moteur apparait dans l’organisation fantasmatique. L’auto-empathie va s’y déployer : processus par lequel un sujet se met à la place de l’autrui-en-soi, produisant un regard intériorisé sur soi pour représenter son monde subjectif. La médiatisation de ce processus d’auto-empathie dans les mondes virtuels va permettre au sujet de se mettre à la place d’une figure qui le représente, de telle façon que son attention et son empathie pour cette figure sont tournées indirectement vers lui-même. Ce second temps d'empathie virtuelle pour une figure de soi, que nous appelons auto-empathie médiatisée par un avatar ou auto-empathie virtuelle, favoriserait dans un troisième temps le développement d’une empathie pour soi. Enfin dans un quatrième temps, dans les jeux de rôle en ligne multi-joueurs, serait favorisé le développement d’une nouvelle forme de travail du lien intersubjectif : différenciateur plutôt que sexuel, engageant l’action dans des proto-conversations plutôt que les émotions entre joueurs, et ressortant du domaine fantasmatique, l’autre joueur étant toujours représenté par le sujet avant d’être perçu, sollicitant entre les joueurs un désir d’intersubjectivité par lequel il faut entendre le désir d’une rencontre dans le monde réel d’un autre joueur par la mise en jeu d’un fantasme dans lequel les représentations imaginaires sont tournées vers la figuration, imaginaire également, d’un sujet réel derrière un autre avatar
Video games propose a new form of subjectivity concerning action in motion, which motor appears in fantasy organization. Auto-empathy will deploy: process by which a subject puts himself instead of the other-in-self, producing an internalized view of self in order to represent his subjective world. The mediation of self-empathy process in virtual worlds will allow the subject to identify with the figure that represents him in the virtual worlds, so that his attention and empathy for this figure are turned indirectly towards himself. This second stage of virtual empathy for a self-figure, which we call self-empathy mediated by an avatar or virtual self-empathy, favors in a third time the development of empathy for oneself. Finally, in a fourth step in the multi-player online role-playing games, the development of a new form of intersubjective relationship work is favored: differentiating rather than sexual, engaging the action in proto-conversations rather than emotions between players and emerging from fantasy domain, the other player being always represented by the subject before being seen creates between players a desire for intersubjectivity through which the desire for a meeting in the real world of another player by putting in a fantasy in which imaginary representations are turned into figuration, also imaginary, of a real subject behind another avatar

Cette recherche étudie l‘utilisation du jeu vidéo pour l’apprentissage des langues étrangères en classe. L’étude porte sur l’intégration de ce support issu de pratiques informelles au contexte formel de la classe de langue. A la fois ludique et à visée d’apprentissage, le ‘jeu vidéo d’apprentissage’ incarne un oxymore, point de tension entre deux pôles, celui du scolaire et celui du jeu. Ce travail se concentre plus spécifiquement sur la notion de ludique. Comment, par le jeu vidéo d’apprentissage, activer une attitude ludique hypothétiquement porteuse d’une implication accrue de l’apprenant, celle-ci menant possiblement à une augmentation et une complexification des productions / interactions en langue étrangère ? Cette recherche s’inscrit dans le cadre du projet Eveil-3D et elle analyse l’accueil fait par un échantillon d’apprenants à deux jeux vidéo d’apprentissage partageant le même scénario mais conçus selon deux modèles différents. Elle a pour objectif d’aboutir tant à un modèle de conception qu’à un modèle de scénario, pensés spécifiquement pour l’apprentissage des langues médiatisées par le jeu vidéo
This research examines the use of video games in foreign language classrooms. It investigates the integration of this digital medium, originating as an informal leisure activity, in a formal language learning classroom setting. The ‘learning video game’, which refers to both the act of learning and the act of play, can be seen as an oxymoron encompassing seriousness as well as fun. This work focuses on the fun aspect. This work is motivated by the following research question: how can the use of a learning video game foster a playful attitude, hypothetically conducive to a greater involvement of the learner, while also potentially leading to increaseand complexification in student foreign language production and interaction? As a part of the Eveil 3D-project, this study analyses reception from a sample of learners to two learning games which have the same scenario but were completed according to two different game design models. The findings provide both a game design model and a scenario template in order to support foreign language learning through the use of the video game

Apprendre à lire est une activité complexe qui s'appuie sur différentes capacités cognitives, dont l'attention visuelle. Absente des programmes scolaires, le rôle de l'attention visuelle pour l'apprentissage de la lecture est pourtant largement documenté dans la littérature scientifique. Dans cette thèse, nous avons donc conçu un logiciel éducatif original d'entraînement de l'attention visuelle, Evasion, et évalué l'impact de son utilisation au sein de la classe.Pour ce faire, une revue de littérature a été menée pour identifier plus précisément quelles sont les dimensions de l'attention visuelle impliquées en lecture et comment les entraîner au mieux. Un cadre conceptuel théorique que nous avons développé permet d'interpréter ces éléments et suggère que les dimensions à cibler sont la quantité totale d'attention visuelle et sa dispersion dans l'espace. Ces deux dimensions semblent particulièrement bien entraînées par les jeux vidéo d'action, dont l'effet sur l'attention visuelle a été lui aussi expliqué dans le cadre de notre modèle.Pour les entraîner au mieux au sein d'Evasion, nous avons mêlé les tâches, dont l'effet sur ces dimensions a été validé, avec les propriétés des jeux vidéo d'action. Notre logiciel prend la forme de quatre mini-jeux, dont les propriétés s'ajustent au niveau de l'élève grâce à un algorithme d'adaptation de la difficulté développé par notre équipe. Evasion devait être utilisé en classe pendant 10~h au total, à raison de 3 sessions hebdomadaires de 20 minutes. L'expérimentation a porté sur 730 élèves de CP répartis en deux groupes d’entraînement. Les deux groupes étaient appariés quant à leurs compétences cognitives avant entraînement. En post-entraînement, les performances du groupe Evasion ont été comparées à celles du groupe contrôle, qui recevait un entraînement de la compréhension orale en anglais.Les résultats de cette expérience écologique montrent que les capacités d'attention visuelle et de lecture ne progressent pas davantage suite à l'utilisation d'Evasion que suite à l'utilisation d'un entraînement contrôle. Des analyses supplémentaires révèlent que le protocole a été peu suivi en classe, et que le temps d'entraînement est un facteur expliquant l'amplitude de l'amélioration des dimensions attentionnelles ciblées. Par ailleurs, il semblerait que les entraînements proposés aient été trop faciles. Ces résultats ouvrent de nouvelles perspectives sur les améliorations à apporter à notre logiciel et, plus généralement, sur les conditions de mise en oeuvre d'expériences écologiques dont les besoins sont spécifiques
Learning to read is a complex activity that relies on different cognitive abilities, including visual attention. The role of visual attention in learning to read is widely documented in the scientific literature but absent from school curricula. In this thesis work, we designed an original educational software, called Evasion, for visual attention training in the classroom and we evaluated its impact on beginning readers' performance.A literature review was first conducted to identify the dimensions of visual attention that are involved in reading and how best to train them. We then propose a conceptual framework which allows us to interpret these results. We conclude that the dimensions to be targeted are the total amount of visual attention resources and attention spatial dispersion. These two facets of attention seem to be particularly well driven by action video games, whose effect on visual attention has also been characterized in our model.To train visual attention resources and dispersion as well as possible within Evasion, we have mixed the tasks known to improve these attentional dimensions with the properties of action video games. Our software includes four training mini-games and an adaptive difficulty algorithm developed by our team to adjust the game properties online to the child needs. The training program was provided in classroom over a period of ten weeks at a rate of three 20-minute sessions a week. It was proposed to a large sample of 730 beggining readers for reading difficulty prevention.The impact of Evasion was assessed before and after training as compared to a control group that used an intervention program conceived to improve oral comprehension in English. The results of this ecological experiment show that visual attention and reading did not improve more following Evasion than control training. Additional analyses revealed that training time was poorly respected while this factor relates to the magnitude of improvement in the attentional dimensions we targeted. The analyses further suggest a problem in the level of difficulty of the mini-games. Overall, our work opens up new perspectives on the improvements to be made to our software and, above all, on the conditions for successful implementation of ecological experiments

Nous apprenons très jeunes une quantité de règles nous permettant d'interagir avec d'autres personnes: des conventions sociales. Elles diffèrent des autres types d'apprentissage dans le sens où les premières personnes à les avoir utilisées n'ont fait qu'un choix arbitraire parmi plusieurs alternatives possibles: le côté de la route où conduire, la forme d'une prise électrique, ou inventer de nouveaux mots. À cause de celà, lorsqu'une nouvelle convention se crée au sein d'une population d'individus interagissant entre eux, de nombreuses alternatives peuvent apparaître et conduire à une situation complexe où plusieurs conventions équivalentes coexistent en compétition. Il peut devenir difficile de les retenir toutes, comment faisons-nous pour trouver un accord efficacement ? Nous exerçons communément un contrôle actif sur nos situations d'apprentissage, en par exemple sélectionnant des activités qui ne soient ni trop simples ni trop complexes. Il a été montré que ce type de comportement, dans des cas comme l'apprentissage sensori-moteur, aide à apprendre mieux, plus vite, et avec moins d'exemples. Est-ce que de tels mécanismes pourraient aussi influencer la négociation de conventions sociales? Le lexique est un exemple particulier de convention sociale: quels mots associer avec tel objet ou tel sens? Une classe de modèles computationels, les Language Games, montrent qu'il est possible pour une population d'individus de construire un langage commun via une série d'interactions par paires. En particulier, le modèle appelé Naming Game met l'accent sur la formation du lexique reliant mots et sens, et montre une typique explosion de la complexité avant de commencer à écarter les conventions synonymes ou homonymes et arriver à un consensus. Dans cette thèse, nous introduisons l'idée de l'apprentissage actif et du contrôle actif de la croissance de la complexité dans le Naming Game, sous la forme d'une politique de choix du sujet de conversation, applicable à chaque interaction. Différentes stratégies sont introduites, et ont des impacts différents sur à la fois le temps nécessaire pour converger vers un consensus et la quantité de mémoire nécessaire à chaque individu. Premièrement, nous limitons artificiellement la mémoire des agents pour éviter l'explosion de complexité locale. Quelques stratégies sont présentées, certaines ayant des propriétés similaires au cas standard en termes de temps de convergence. Dans un deuxième temps, nous formalisons ce que les agents doivent optimiser, en se basant sur une représentation de l'état moyen de la population. Deux stratégies inspirées de cette notion permettent de limiter les besoins en mémoire sans avoir à contraindre le système, et en prime permettent de converger plus rapidement. Nous montrons ensuite que la dynamique obtenue est proche d'un comportement théorique optimal, exprimé comme une borne inférieure au temps de convergence. Finalement, nous avons mis en place une expérience utilisateur en ligne sous forme de jeu pour collecter des données sur le comportement d'utilisateurs réels placés dans le cadre du modèle. Les résultats suggèrent qu'ils ont effectivement une politique active de choix de sujet de conversation, en comparaison avec un choix aléatoire.Les contributions de ce travail de thèse incluent aussi une classification des modèles de Naming Games existants, et un cadriciel open-source pour les simuler
Social conventions are learned mostly at a young age, but are quite different from other domains, like for example sensorimotor skills. The first people to define conventions just picked an arbitrary alternative between several options: a side of the road to drive on, the design of an electric plug, or inventing a new word. Because of this, while setting a new convention in a population of interacting individuals, many competing options can arise, and lead to a situation of growing complexity if many parallel inventions happen. How do we deal with this issue?Humans often exhert an active control on their learning situation, by for example selecting activities that are neither too complex nor too simple. This behavior, in cases like sensorimotor learning, has been shown to help learn faster, better, and with fewer examples. Could such mechanisms also have an impact on the negotiation of social conventions ? A particular example of social convention is the lexicon: which words we associated with given meanings. Computational models of language emergence, called the Language Games, showed that it is possible for a population of agents to build a common language through only pairwise interactions. In particular, the Naming Game model focuses on the formation of the lexicon mapping words and meanings, and shows a typical burst of complexity before starting to discard options and find a final consensus. In this thesis, we introduce the idea of active learning and active control of complexity growth in the Naming Game, in the form of a topic choice policy: agents can choose the meaning they want to talk about in each interaction. Several strategies were introduced, and have a different impact on both the time needed to converge to a consensus and the amount of memory needed by individual agents. Firstly, we artificially constrain the memory of agents to avoid the local complexity burst. A few strategies are presented, some of which can have similar convergence speed as in the standard case. Secondly, we formalize what agents need to optimize, based on a representation of the average state of the population. A couple of strategies inspired by this notion help keep the memory usage low without having constraints, but also result in a faster convergence process. We then show that the obtained dynamics are close to an optimal behavior, expressed analytically as a lower bound to convergence time. Eventually, we designed an online user experiment to collect data on how humans would behave in the same model, which shows that they do have an active topic choice policy, and do not choose randomly. Contributions from this thesis also include a classification of the existing Naming Game models and an open-source framework to simulate them

Ce travail propose une approche des drogues et dépendances du point de vue d'une anthropologie par la culture matérielle. Le rapport aux objets est interrogé dans le contexte de la consommation de drogues licites et illicites, « réelles » et métaphoriques. Par un triple travail ethnographique – pauses café-cigarette, cannabis et pratique du jeu vidéo – le processus d'actualisation du sens construit dans l'action est décrit et analysé, au-delà de sa dimension symbolique. La dépendance, en tant que « catégorie » de relation aux objets et à autrui dans la vie quotidienne, est mise en regard avec les notions de routine et de ritualisation. La « drogue » apparaît comme « objet de pouvoirs » : elle cristallise l'idée de puissance de l'objet sur le sujet ; elle exemplifie les effets de domination inhérents à la construction sociale des normes (déviance, légitimité). L'attention ainsi portée au corps en action sur la matière et sur autrui amène à une réflexion plus large sur sa place dans le processus de subjectivation, entendu comme construction d'un sujet agissant sur lui-même en s'inscrivant dans des réseaux de pouvoirs.

Ce mémoire se concentre sur la figure de l’héroïne d’action dans les jeux vidéo. La culture vidéoludique, qui glorifie la masculinité militarisée, tend à sexualiser les personnages féminins et à négliger les préférences des joueuses afin de cibler les hommes et les garçons. La figure de l’héroïne d’action naît du désir d’inclusion des femmes dans la culture du jeu vidéo. Ces protagonistes féminins, bien que souvent objectifiés comme le témoigne le célèbre personnage de Lara Croft, présentent tout de même un potentiel subversif en envahissant l’espace traditionnellement masculin. Ce mémoire analyse quelques protagonistes qui correspondent à la figure de l’héroïne et la remodèlent.
This master thesis focuses on the action heroine trope in video games. The video game culture, which glorifies militarized masculinity, tends to sexualize female characters and to neglect the preferences of female players by targeting men and boys. The action heroine trope is born from the desire to include women in the video game culture. These female protagonists are often sexualized, such as the famous Lara Croft, but they also have a subversive potential by invading a traditional masculine space. This master thesis analyzes a few characters that are modeled and reshaped on the action heroine trope.

Ce mémoire porte sur la culpabilité du joueur pour des actions qu’il pose dans les jeux vidéo. L’objectif est de cibler les situations de jeu et les conditions psychosociologiques à l’émergence de cette émotion. Le premier chapitre compare l’expérience émotionnelle du spectateur et du joueur principalement dans la relation que ces derniers entretiennent avec des personnages. Le deuxième chapitre offre une étude détaillée de la culpabilité telle que vécue ordinairement, particulièrement de son processus cognitif et de ses fonctions sociales. Le troisième chapitre propose un modèle du processus de la culpabilité du joueur qui inclut des variables relatives à l’expérience des jeux vidéo et au design de jeu. Le modèle est mis en application dans l’analyse d’un corpus de jeux vidéo solos et narratifs à différents degrés, qui visent à provoquer des fautes morales chez le joueur et à les lui faire prendre conscience.
This master’s thesis focuses on player’s guilt based on gameplay actions. The objective is to target video games situations and psychosociological conditions leading to this emotion. The first chapter compares the spectator’s emotional experience with that of the player mainly in their relations with characters. The second chapter offers a detailed study of guilt as ordinarily experienced, especially of its cognitive process and its social functions. The third chapter introduces a theoretical model of the player’s guilt process which includes variables related to the experience of video games and game design. The model is applied to the analysis of a corpus of single-player narrative games that intent to provoke the player to commit wrongdoings and to make him aware of them.

Hot-jet ignition of a combustible mixture has application in IC engines, detonation initiation, and wave rotor combustion. Numerical predictions are made for ignition of combustible mixtures using a traversing jet of chemically active gas at one end of a long constant-volume combustor (CVC) with aspect ratio similar to a wave rotor channel. The CVC initially contains a stoichiometric mixture of ethylene or methane at atmospheric conditions. The traversing jet issues from a rotating pre-chamber that generates gaseous combustion products, assumed at chemical equilibrium for estimating major species. Turbulent combustion uses a hybrid eddy-break-up model with detailed finite-rate kinetics and a two-equation k-ω model. The confined jet is observed to behave initially as a wall jet and later as a wall-impinging jet. The jet evolution, vortex structure and mixing behavior are significantly different for traversing jets, stationary centered jets, and near-wall jets. Pressure waves in the CVC chamber affect ignition through flame vorticity generation and compression. The jet and ignition behavior are compared with high-speed video images from a prior experiment. Production of unstable intermediate species like C2H4 and CH3 appears to depend significantly on the initial jet location while relatively stable species like OH are less sensitive.

For the safety design of the Fast Breeder Reactor (FBR), it is strongly required that the Post Accident Heat Removal (PAHR) is achieved after a hypothetical Core Disruptive Accident (CDA). In the PAHR, it is important that the molten material is fragmented to be solidified by the sodium coolant with high boiling point and thermal conductivity. Furthermore, in order to estimate whether the molten material jet is completely solidified in sodium coolant or not, it is necessary to evaluate the jet breakup length. Although there are many previous studies on the jet breakup length, the tendency of jet breakup length is different for the previous studies. To estimate jet breakup length, it is necessary to understand the interaction between molten core material and coolant. The objective of the present study is to clarify the influence of the interfacial behavior of the jet on the fragmentation behavior on the jet surface. The experiments are conducted to obtain the interfacial behavior and the fragmentation behavior on the jet surface by injecting transparent Fluorinert™ (FC-3283) into water. The jet breakup behavior of the Fluorinert and the fragmentation behavior on the jet surface in pool are observed by using high speed video camera. To clarify the influence of interfacial behavior on jet surface fragmentation, it is necessary to clarify the effect of the internal flow of the jet and the surrounding flow structure on the interfacial behavior. The internal and the external velocity distribution of the jet are obtained by Particle Image Velocimetry (PIV) technique from the visual data. Shear stress is evaluated from the velocity data obtained by PIV technique. Reynolds stress and turbulent energy are also evaluated from the velocity data. As the results, shear stress becomes large along the interfacial wave. The maximum value of shear stress is decreased toward downstream. Reynolds stress becomes large at the jet surface. The vortex around the interfacial wave is observed by PIV measurement. The local shear stress acts on the interfacial wave. It is suggested that the local shear stress on the jet surface causes the fragmentation. From the experimental results, the interaction between the interfacial behavior of the jet and flow structure of the jet and surrounding fluid are discussed. The dominant mechanism of the fragmentation behavior and the influence of local shear stress at the interface on the fragementation are also discussed.

Steam injector (SI) is a passive jet pump which is driven by high-performance steam condensation onto water jet and it is expected to be active at severe accident of nuclear power plant with no electricity. SI is mainly consists of convergent-divergent nozzle. Supersonic steam flow condenses onto water jet in the mixing nozzle and mass, momentum, and energy of steam is transferred to water in the mixing nozzle. Condensed water jet is accelerated at the throat and kinetic energy is converted into pressure in the diffuser, which produces higher pressure than inlet steam pressure. It is easy to apply the SI to nuclear power plant since SI has quite simple and compact structures. The objectives of the present study are to clarify the mechanism of heat and momentum transfer in the mixing nozzle and to determine operating range of SI for practical use. A transparent test section is adopted to conduct visualization of the flow structure with a high-speed video camera as well as measurement of pressure distribution in mixing nozzle, throat, and diffuser with changing back pressure. Fundamental parameters change between operative and inoperative state of the injector were evaluated by measuring pressure and temperature distribution along axial direction of the test section. Discharge pressure as one of operating characteristics of the injector was also measured in changing back pressure by decreasing the opening ratio of the back pressure valve attached downstream of the test section. It was confirmed that discharge pressure increased and the injector became inoperative unsteadily with decreasing opening ratio of the back pressure valve just after it produced the maximum discharge pressure. In the present investigation, this maximum discharge pressure is evaluated as the operation limit of the injector. Furthermore, discharge pressure from diffuser, which is one of the indicators of operating performance as well as operating limit is predicted from inlet condition adopting one-dimensional analysis model proposed previously. By comparing analytical result with experimental data, as well as visualization of flow structure in throat and diffuser, physics model including two-phase flow structure with shock wave which was observed at throat and diffuser are discussed in order to predict injector’s operation with high accuracy.

The Jet Propulsion Laboratory at the Berlin University of Technology has recently introduced a multimedia aeroengine design project under the working title “Project Jet Propulsion”. The seminar, in which the German aeroengine industry is actively involved, is directed at students who have successfully finished their basic engineering training course. The objective of the course is to provide experience of all stages of the complete design process of an engine component in a genuine industrial working environment. The component is selected to ensure that a wide range of design requirements, including customer requirements, aero-thermodynamic and mechanical design, costing and certification, have to be taken into consideration. An experiment supporting the design completes the course. The course is attended by a fixed number of students and lasts for one year. It involves fortnightly working sessions, which are organized the same way as they would be in the industry, with minutes being kept and action lists checked. The students are encouraged to work on their own initiative, identify the necessary tasks and set up a schedule to accomplish the work within the given time limit of the course duration. Industry participates in a variety of ways. At the end of each working session experts from the companies involved join in a telephone conference, giving their comments on the work of the group and answering questions. A video conference supported by one of the industrial partners is also on the agenda. During the course, both companies involved are visited and progress is reviewed in an intermediate and a final design review respectively. No scripts are handed out during the course. Communication is done by e-mail and progress reports, memoranda and minutes of the meetings are made available on the internet.

In order to decommission nuclear reactors and to improve the safety of BWR, it is important to estimate the falling behavior of molten core jet in the reactor vessel of BWR when an accident occurred as can be seen from Fukushima Daiichi nuclear power plant accident. Since the BWR lower plenum is consisted with various complicated structures, it is suggested that the jet falling behavior is affected by these structures. Thus we are developing the numerical simulation method to estimate the molten core falling behavior in BWR. To verify the code for the case of the BWR core melt accident, it is necessary to obtain the experimental data and validate the code by comparing the numerical results with the experimental results. The purpose of this study is to investigate the influence of these structures on behavior of jet breakup and fragmentation, and to construct the benchmarks of the numerical simulation experimentally. We used molten core simulant material and simulate the molten core falling behavior, focusing on the hydrodynamic behavior. The 1/10 planar type test section simulated the arrangement of complicated structures in the BWR lower plenum is used. Jet injection experiments were conducted under some conditions that experimental parameters were flow rate and nozzle diameter. To clarify the influence of complicated structures on the jet behavior, experiments were performed in the conditions with and without structures. Jet falling behaviors were recorded by a high speed video camera. The fragment diameters were measured from image by means of image processing techniques. Visual measurement is usually used to measure fragment diameter, but it will contain the arbitrariness and the amount of fragments are small. Since the outline of fragment is easy to recognize by the difference of refractive index between gas and liquid, image processing for measuring the diameters is used in gas liquid flow. On the other hand, it is difficult to recognize the interface in liquid-liquid flow. We developed the new image processing filter for detecting the outline of fragments precisely and established the image processing method including this filter. We measured about ten thousand fragments precisely and automatically. The measurement of fragment diameter was implemented by the image processing method mentioned above. The histogram of fragment diameter distribution shows that it can be fitted by the lognormal distribution in condition with and without structures. We calculated the volume median diameters in all conditions. The diameters were smaller that depended on the increasing injection velocity. Comparing between condition with and without structures, the fragment diameters became small in condition with structures than without structures. Since the velocity of tip of the jet was larger in condition with structures (Saito et al., J. Nucl. Sci. Tech, 2015), the velocity gradient between the jet and ambient fluid also would be larger. The shear force strongly acting on the interface made the diameter small.

Existing thermal barrier coatings (TBC) can be adapted enhancing their functionalities such that they not only protect critical components from hot gases, but also can sense their own material temperature or other physical properties. The self-sensing capability is introduced by embedding optically active rare earth ions into the thermal barrier ceramic. When illuminated by light the material starts to phosphoresce and the phosphorescence can provide in-situ information on temperature, phase changes, corrosion or erosion of the coating subject to the coating design. The integration of an on-line temperature detection system enables the full potential of TBCs to be realised due to improved accuracy in temperature measurement and early warning of degradation. This in turn will increase fuel efficiency and will reduce CO2 emissions. This paper reviews the previous implementation of such a measurement system into a Rolls-Royce jet engine using dysprosium doped yttrium-stabilised-zirconia as a single layer and a dual layer sensor coating material. The temperature measurements were carried out on cooled and uncooled components on a combustion chamber liner and on nozzle guide vanes respectively. The paper investigates the interpretation of those results looking at coating thickness effects and temperature gradients across the TBC. For the study a specialised cyclic thermal gradient burner test rig was operated and instrumented using equivalent instrumentation to that used for the engine test. This unique rig enables the controlled heating of the coatings at different temperature regimes. A long-wavelength pyrometer was employed detecting the surface temperature of the coating in combination with the phosphorescence detector. A correction was applied to compensate for changes in emissivity using two methods. A thermocouple was used continuously measuring the substrate temperature of the sample. Typical gradients across the coating are less than 1K/μm. As the excitation laser penetrates the coating it generates phosphorescence from several locations throughout the coating and hence provides an integrated signal. The study successfully proved that the temperature indication from the phosphorescence coating remains between the surface and substrate temperature for all operating conditions. This demonstrates the possibility to measure inside the coating closer to the bond coat. The knowledge of the bond coat temperature is relevant to the growth of the thermally grown oxide which is linked to the delamination of the coating and hence determines its life. Further, the data is related to a one dimensional phosphorescence model determining the penetration depth of the laser and the emission. Note: a video of the measurement system can be watched under: [http://www.youtube.com/watch?v=T6uXN1__Z7I].