Dissertations / Theses on the topic 'Born analyticals'

This study aspired to gain a more a nuanced understanding of the emerging analytics technologies and the vital capabilities that ultimately drive evidence-based decision making. Big data technology is widely discussed by varying groups in society and believed to revolutionize corporate decision making. In spite of big data's promising possibilities only a trivial fraction of firms deploying big data analytics (BDA) have gained significant benefits from their initiatives. Trying to explain this inability we leaned back on prior IT literature suggesting that IT resources can only be successfully deployed when combined with organizational capabilities. We identified key theoretical components at an organizational, relational, and human level. The data collection included 20 interviews with decision makers and data scientist from four analytical leaders. Early on we distinguished the companies into two categories based on their empirical characteristics. The terms “Born analyticals” and “Big intelligent firms” were coined. The analysis concluded that social, non-technical elements play a crucial role in building BDA abilities. These capabilities differ among companies but can still enable BDA in different ways, indicating that organizations´ history and context seem to influence how firms deploy capabilities. Some capabilities have proven to be more important than others. The individual mindset towards data is seemingly the most determining capability in building BDA ability. Varying mindsets foster different BDA-environments in which other capabilities behave accordingly. Born analyticals seemed to display an environment benefitting evidence based decisions.

The fully quantum mechanical 'direct-potential-fit' (DPF) method has become increasingly widely used in the reduction of diatomic spectra. The central problem of this method is the representation of the potential energy and Born-Oppenheimer breakdown (BOB) correction functions. There are a number of problems associated with the existing method and potential forms. This thesis delineates these problems and finds solutions to some of them. In particular, it is shown that use of a different expansion variable and a new treatment of some of the expansions resolves most of the problems. These techniques have been successfully tested on the ground electronic states of the coinage metal hydrides and the Rb2 molecule. To address the problem of representing 'barrier' potential curves, a flexible new functional form, the 'double-exponential long-range' (DELR) potential function, is introduced and applied to the B barrier state of Li2. In addition, the Lambda-doubling level splitting which occurs for singlet Pi electronic states has been taken into account by extending the effective Schrodinger equation. The computer program DSPotFit developed in our laboratory for performing DPF analyses has been extended to incorporate the ability to fit the analytical potential energy functions to tunneling predissociation line widths for quasibound levels. Finally, an attempt is made to investigate whether there exists a hump in the ground state rotationless potential curve of beryllium hydride.

Boron (B) is a rare element on Earth crust with a natural abundance of 0.001%. However, boron content of water and soils may be significantly high in the regions with rich boron reserves. In addition, extensive use of agrochemicals in soils as well as various natural processes increases the boron concentration in water. Despite B is an essential element for all living creatures, it may pose risks at high level exposures. World Health Organization (WHO) has recommended a daily intake of 1 to 13 mg B for adults. Turkey has almost 70% of world boron reserves principally in four regions: K&uuml<br>tahya, Emet<br>Balikesir, Bigadi&ccedil<br>Eskisehir, Kirka and Bursa, Kemalpasa. The boron content of water in these regions may go up to significant levels. Therefore, it is important to determine B in drinking water from these regions. Electrothermal atomic absorption spectrometry (ETAAS) is a relatively sensitive technique for determination of boron. However, the technique suffers from formation of molecular boron compounds. Therefore, use of chemical modifiers and pyrolytically coated graphite tubes modified with refractory carbide forming elements (Ta, W, Zr, Pd, Ru, Os) were utilized to develop a reliable and sensitive method. Based on optimization studies, Tantalum (Ta) coated tube and co-injection of 5.0 &micro<br>L 0.01 mol/L Ca(NO3)2, 5.0 &micro<br>L 0.05 mol/L citric acid together with 15.0 &micro<br>L sample solution prepared in 1000 mg/L Mg(NO3)2 have been chosen as optimum conditions. Optimum temperatures for pyrolysis and atomization temperatures were determined as 1100 and 2700 &deg<br>C, respectively. Under these conditions, a detection limit of 0.088 mg/L and a characteristic mass of 186 pg for 15.0 &micro<br>L sample volume were obtained. The accuracy of the method was checked by EnviroMAT-Waste Water EU-L-1 CRM and NIST 1573a Tomato Leaves SRM analyses. Drinking water samples were collected from Balikesir, Bigadi&ccedil<br>and K&uuml<br>tahya, Emet and analyzed by the developed method. Samples were also analyzed by more sensitive techniques<br>ICP-OES and ICP-MS for a comparison study. The results are compatible with each other.

Ce travail s’inscrit dans une problématique générale de l’analytique de l’apprentissage numérique et particulièrement dans le contexte du projet ANR HUBBLE, un observatoire national permettant le dépôt de processus d’analyse de haut niveau. Nous nous intéressons principalement à la communication des données d’analyse aux utilisateurs en mettant à leur disposition des tableaux de bord d'apprentissage (TBA). Notre problématique porte sur l’identification de structures génériques dans le but de générer dynamiquement des TBA sur mesure. Ces structures doivent être à la fois génériques et adaptables aux besoins d’utilisateurs. Les travaux existants proposent le plus souvent des TBA trop généraux ou développés de manière adhoc. Au travers du projet HUBBLE, nous souhaitons exploiter les décisions des utilisateurs pour générer dynamiquement des TBA. Nous nous sommes intéressés au domaine de l’informatique décisionnelle en raison de la place des tableaux de bord dans leur processus. La prise de décision exige une compréhension explicite des besoins des utilisateurs. C'est pourquoi nous avons adopté une approche de conception centrée sur l'utilisateur dans le but de lui fournir des TBA adaptés. Nous proposons aussi un processus de capture des besoins qui a permis l’élaboration de nos modèles (indicateur, moyens de visualisation, utilisateur, …). Ces derniers sont utilisés par un processus de génération implémenté dans un prototype de générateur dynamique. Nous avons procédé à une phase d'évaluation itérative dont l’objectif est d'affiner nos modèles et de valider l'efficacité de notre processus de génération ainsi que de démontrer l'impact de la décision sur la génération des TBA<br>This work is part of a broader issue of Learning Analytics (LA). It is particularly carried out within the context of the HUBBLE project, a national observatory for the design and sharing of data analysis processes. We are interested in communicating data analysis results to users by providing LA dashboards (LAD). Our main issue is the identification of generic LAD structures in order to generate dynamically tailored LAD. These structures must be generic to ensure their reuse, and adaptable to users’ needs. Existing works proposed LAD which remains too general or developed in an adhoc way. According to the HUBBLE project, we want to use identified decisions of end-users to generate dynamically our LAD. We were interested in the business intelligence area because of the place of dashboards in the decision-making process. Decision-making requires an explicit understanding of user needs. That's why we have adopted a user-centered design (UCD) approach to generate adapted LAD. We propose a new process for capturing end-users’ needs, in order to elaborate some models (Indicator, visualization means, user, pattern, …). These models are used by a generation process implemented in a LAD dynamic generator prototype. We conducted an iterative evaluation phase. The objective is to refine our models and validate the efficiency of our generation process. The second iteration demonstrates the impact of the decision on the LAD generation. Thus, we can confirm that the decision is considered as a central element for the generation of LADs

A espectrometria de massas com ionização por electrospray (ES-MS) foi proposta para medidas da razão isotópica de alguns metais de transição e boro através de complexos com carga simples e ligantes monoisotópicos. Vários experimentos combinando estes elementos com iodeto e fluoreto são apresentados. Cloreto e cianeto foram utilizados em estudos sobre o comportamento destes complexos. De um modo geral, os metais geraram picos mais intensos com cloreto e iodeto, já o boro forneceu um cluster abundante como BF4&#175;. A principal tendência é a formação de espécies com carga simples pela associação dos íons metálicos com os ânions presentes na solução ou pela perda de um ou mais ligantes. Em alguns casos, esta tendência é mais forte que a manutenção do estado de oxidação do metal na fase líquida. Para cobre e ferro, a variação dos estados de oxidação depende do solvente, de outras espécies em solução e das tensões aplicadas ao cone de amostragem. Estes e outros resultados mostram que a quantificação e especiação não são tarefas muito fáceis, mas há a possibilidade de usar a técnica para medidas isotópicas com os complexos formados com os ligantes monoisotópicos. As principais vantagens neste caso seriam a mudança de m/z para região de massa alta, o que diminui as chances de interferência isobárica, e a ausência de hidretos, comumente observados no modo de íons positivos e sem ligantes. O tetrafluoroborato foi proposto para determinações de razão isotópica do boro (10B/11B). Os espectros obtidos em condições brandas mostram-se livres de interferência isobárica e com resolução de linha base na região de m/z 86 e 87, que corresponde a 10BF4&#175; e 11BF4&#175;. Soluções predominantemente aquosas em meio ácido não devem ser armazenadas, pois ocorre a hidrólise BF4&#175;. Para minimizar o efeito de memória na fonte de íons, um novo contra eletrodo, tipo cross-flow, foi manufaturado e substituiu o contra-eletrodo original do tipo pepper-pot. Além disto, foram feitos estudos sobre a ação de algumas substâncias que formam complexos não voláteis com boro, como manitol, Triton X-100 e amônia. Estas substâncias são comumente usadas para auxiliar na minimização do efeito de memória em ICP-MS. Observou-se uma diminuição no tempo necessário para limpar a fonte de electrospray, mas o resultado não foi satisfatório. Um procedimento alternativo - e bem mais eficaz - é provocar a hidrólise do BF4&#175; residual, o que pode ser feito com um spray de ácido sulfúrico 1mmol/L. Descarga corona é um evento raro, mas que altera drasticamente o espectro. Assim, a mediana e o desvio absoluto da mediana (MAD) foram usados como avaliadores da tendência central e do desvio, respectivamente. A influência das tensões da fonte, do detector, e os fluxos dos gases sobre a razão isotópica foram investigados. Nenhum efeito sistemático foi observado, mas existe discriminação de massas que pode ser corrigida por calibração com padrão certificado do National Institute of Standards and Technology (NIST) de ácido bórico SRM 951. Foram realizados estudos de interferência isobárica e supressão da espécie de interesse. Íons comuns como K+, Na+, Mg2+, Ca2+, SO42&#175;, Br&#175; e Cl&#175; não causaram interferência isobárica e fracionamento isotópico. A precisão obtida para a medida da razão isotópica para injeções de 5 min de solução 100 &#181;mol/L de B foi tipicamente 0,4 %, que é comparável àquela obtida por ICP-MS e TIMS. O método proposto também permite a quantificação através da diluição isotópica. Como a técnica de electrospray exige uma concentração do analito superior a 10-6 mol/L para obter um pico detectável e não sofrer supressão pelos eletrólitos em solução, um passo importante na análise de amostras é a pré-concentração. Procedimentos de abertura, pré-concentração e eliminação de interferentes catiônicos foram propostos para amostras de solo, sabão em pó e folhas de algodoeiro. Além destes, duas amostras de plantas certificadas para concentração de boro, pelo National Institute of Standards and Technology, foram avaliadas - folhas de pessegueiro e folhas de macieira. Os resultados obtidos foram excelentes, mostrando que o procedimento desenvolvido para a abertura da amostra, pode vir a ser um método bastante simples e eficaz para análise de boro em amostras reais. É claro que dependendo da amostra a matriz será diferente e outros procedimentos precisarão ser tomados.<br>A negative-mode electrospray ionization mass spectrometry was proposed to study of isotopic measurements some transition metal ions and boron through of complexes with monoisotopoic ligands. Several experiments combining these elements with iodide, fluoride, chloride, and cyanide are presented. Methanol/water was mainly used as the solvent in order to reduce the surface tension and, thus, the voltage at the capillary tip. Some common behaviors could be observed. Metals give more abundant peaks with iodide and chloride, while boron gives an abundant cluster for BF4&#175;. In general, the complexes are singly charged formed by association of the metal ions with the anions present in the solution or by loss of one or more ligands from species previously present in solution. In some cases, this tendency surpasses the maintenance of the oxidation state of the metal in liquid phase. The interconversion of low and high oxidation states of copper and iron ions depends on the solvent and other species from the solution, but in the gas phase the high oxidation state species can be reduced by collision induced dissociation at low sampling cone voltages. Surprisingly, ferricyanide and ferrocyanide anions render almost the same spectrum. The results suggest that [Fe(CN)6]4&#175; lose one electron to a leaving solvent molecule to form [Fe(CN)6]3&#175; in the final steps of desolvation. These and other results suggest that, for the ligands studied in this work, quantitation and speciation are not easy tasks, but there is the possibility of to perform isotope ratio measurements with the complexes formed with monoisotopic anions. The main advantages in this case would be the shift of the m/z to high mass region, which diminishes the chance of isobaric interference, and the inexistence of hydrides, commonly observed in the positive mode ES/MS spectra of metal ions and that cause isobaric interference. The use of electrospray mass spectrometry (ES-MS) of tetrafluoroborate solutions was proposed for the determination of the boron isotopic ratio (10B/11B). When a mixture of methanol and water is used as the solvent and neutral to alkaline medium is kept, spectra obtained at mild electrospray conditions show free-of-interference peaks with base-line resolution in the region of m/z 86 and 87, which corresponds to 10BF4&#175; and 11BF4&#175;. The study was carried out on a quadrupolar mass spectrometer Platform II (Micromass, UK). To minimize the memory effect in the ion source, the original pepper pot counter electrode was substituted by a crossflow counter electrode. This geometry reduces the memory effect, but a cleaning process based on mannitol injection assures a suitable background level. Another procedure to eliminate the memory effect could be the hydrolyze of BF4&#175; ion using a sulfuric acid spray. Occasional corona discharge corrupts the numerical results, thus median and median of absolute deviations were used as central tendency and dispersion estimators, respectively, because spikes and outliers do not affect them. The influence of the source and detector voltages and the gas flows over the isotopic ratio was investigated. No systematic effect was observed, but there are mass discrimination and drift that were corrected by successive injection of solution of boric acid NIST 951 converted to sodium tetrafluoroborate. Common ions such as K+, Na+, Mg2+, Ca2+, SO42&#175;, Br&#175; and Cl&#175; do not cause significant isobaric interference and isotopic fractionation. The isotopic ratio precision obtained for 5-min injection of 100-&#181;mol/L boron solution at 10-&#181;L/min was typically 0.4%, which is comparable to those from induced coupled plasma (ICP-MS) and thermal ionization mass spectrometry (TIMS). Besides, through of isotope dilution it is possible quantitative analysis of boron. Electrospray needs a minimal concentration of analyte, above of 10-6 mol/L, to obtain a detectable peak and it do not suffer suppression of other electrolytes presents in solution. Therefore, an important step in the analyses of real samples is the pre-concentration and elimination of cationic interference. Procedures of dissolution and digestion to soil, washing powder and plants were proposed. Besides, two certified samples of plants from National Institute of Standards and Technology were evaluated- peach leaves and apple leaves. The results obtained were excellent, showing that the procedure developing can be an alternative method to boron analyses.

Boron element plays an important role for our country since approximately 70% of the world&rsquo<br>s reserves are in Turkey. It is widely used in different areas of industry. Besides being vital for the plants, it is important also for human health. It has been shown that high boron exposure does not affect fertility negatively and also with an increasing boron exposure, risk of prostate and cervical cancers decreases. There are different opinions regarding health effects of boron. There are both positive and negative findings. Therefore, determination of boron in body fluids such as urine and blood is necessary to monitor exposed concentration level and its relation with diseases. Furthermore, these studies may contribute to define a reference value for safe maximum daily boron intake. In this study, a method previously developed by our research group was applied for the determination of boron in urine samples. Urine and blood samples were collected from human subjects living or working in different regions of Balikesir where boron reserves are located. While urine analysis was done by using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), due to lower concentrations of boron in blood, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for blood analysis. A sensitive method was developed using ICP-MS. Samples were digested in microwave oven by applying optimized digestion procedures. Indium (In) and Beryllium (Be) internal standards were spiked into the urine and blood samples, respectively. A sample introduction system containing no glass or silica surfaces was used in ICP-MS to eliminate boron memory effect. Two isotopes of the boron, 10B and 11B, were monitored during the study. Space charge effect due to Na+ ion and carbon interference on B and Be signals was investigated in detail. Limit of Detection was 0.021 mg/L for ICP-OES and it was 2.2 &micro<br>g/L for ICP-MS. The accuracies of the methods were checked by using NIST 1573a Tomato Leaves and BCR Human Hair certified reference materials for urine and blood, respectively.

La thèse se base sur la recherche des possibilités de caractérisation du son aérien de sources sonores arbitraires. A cette fin, une approche particulière est étudiée à l’endroit où la caractérisation de la source est faite via une surface d’interface qui enveloppe totalement ou partiellement la source physique. Deux descripteurs qui dépendent de la fréquence sont definis au travers d’une telle surface: la pression sonore bloquée et l’impédance de la source. Le précédent représente la pression sonore créée par le système d’exploitation source qui agit sur la surface enveloppante quand elle est rendue immobile. Cette dernière représente le rapport des amplitudes de réponse de pression et les amplitudes de vitesse d’excitation normales au travers de la surface. La surface enveloppante définit un volume d’air qui contient la source physique appelée l’espace source. Les deux descripteurs définis sur l’espace source, la pression bloquée et l’impédance de la source sont montrés comme étant intrinsèques à la source, c’est-à-dire indépendants de l’espace acoustique environnant. Une fois définis, ces descripteurs permettent de trouver la pression sonore et la vitesse particulaire normale à la surface de l’interface quand l’espace source est couplé à un espace récepteur arbitraire, c’est-à-dire une pièce. Cela permet alors la prédiction du son dans l’espace récepteur. Les conditions de couplage nécessitent que l’espace récepteur soit caractérisé en utilisant la même surface enveloppante telle que l’espace source. En acceptant de garder à l’esprit la simplicité de la mesure, la surface enveloppante a été conçue vu qu’elle comporte une ou plusieurs surfaces rectangulaires planes. Le défi de la recherche était alors d’obtenir une impédance significative de la surface au travers de la surface plane rectangulaire (continue) ainsi que celle de la pression bloquée compatible avec la formulation de l’impédance. Cela a conduit à une décomposition dans l’espace de la pression sonore et de la vitesse des particules au sein du nombre fini des composants, chacun défini par une amplitude complexe et une distribution dans l’espace particulière. De cette façon, la pression bloquée se réduit à un vecteur d’amplitude de pression complexe, tandis que l’impédance devient une matrice de pression et des rapports d’amplitudes complexes de la vitesse de défauts de de décompositions ont été recherchés dans le détail: la méthode harmonique de surface et la méthode du patch. Le premier se rapproche de la pression de surface et de la vitesse normale par des combinaisons de fonctions de surface trigonométriques en 2D tandis que ce dernier partage la surface en petites parcelles et intervient sur chaque parcelle de façon discrète en utilisant les valeurs moyennes du patch<br>The thesis investigates possibilities of air-borne sound characterisation of arbitrary sound sources. To this end a particular approach is studied where the source characterisation is done via an interface surface which fully or partially envelopes the physical source. Two frequency dependent descriptors are defined across such a surface: the blocked sound pressure and the source impedance. The former represents the sound pressure created by the operating source which acts on the enveloping surface when this is made immobile. The latter represents the ratio of pressure response amplitudes and normal velocity excitation amplitudes across the surface. The enveloping surface defines an air volume containing the physical source, called the source space. The two source descriptors defined on the source space, the blocked pressure and the source impedance, are shown to be intrinsic to the source, i.e. independent of the surrounding acoustical space. Once defined, these descriptors allow one to find the sound pressure and normal particle velocity at the interface surface when the source space is coupled to an arbitrary receiver space, i.e. a room. This in turn allows for sound prediction in the receiver space. The coupling conditions require that the receiver space is characterised using the same enveloping surface as the source space. Bearing the measurement simplicity in mind, the enveloping surface has been conceived as consisting of one or several rectangular plane surfaces. The research challenge was then to obtain meaningful surface impedance across a (continuous) rectangular plane surface as well as the blocked pressure compatible with impedance formulation. This has led to a spatial decomposition of sound pressure and particle velocity into finite number of components, each defined by a complex amplitude and a particular spatial distribution. In this way the blocked pressure reduces to a vector of complex pressure amplitudes while the impedance becomes a matrix of pressure and velocity complex amplitude ratios. Two decomposition methods have been investigated in detail: the surface harmonic method and the patch method. The former approximates the surface pressure and normal velocity by combinations of 2D trigonometric surface functions while the latter splits the surface into small patches and treats each patch in a discrete way, using patch-averaged values

Ce mémoire présente l’étude du comportement d’un flotteur bord à quai. Ce flotteur est constituéd’une bouée de section rectangulaire située à proximité d’une digue verticale. Un modèle analytique linéaire basé sur la théorie de l’écoulement potentiel est réalisé en profondeur d’eau intermédiaire. Un modèle numérique résolvant les équations de Navier-Stockes est développé. Des essais expérimentaux sont également mis au point pour des flotteurs de différentes dimensions et servent de références aux deux autres modèles. La comparaison de ces trois modèles permet de déduire le domaine de validité du modèle analytique, ainsi que la présence d’effets non-linéaires agissant sur le comportement du flotteur.Dans un premier temps, l’impact des dimensions du système sur le comportement du flotteur est quantifié. Les effets non-linéaires sont quantifiés en fonction des grandeurs du système puis une correction du modèle analytique est proposée. Par la suite, la correction du modèle est appliquée au comportement du système incluant un récupérateur d’énergie.Dans un second temps, l’effet du flotteur sur les franchissements de digue est étudié. Les franchissements de digue sont exprimés grâce à la hauteur de houle entre la digue et le flotteur (exprimée par le modèle analytique) et à la formule de Van Der Meer (2002). Ces franchissements sont également estimés de manière expérimentale. Il est montré que lorsque la longueur d’onde de la houle est importante et que le dégagement entre la digue et le flotteur est faible, les franchissements de digue sont réduits par la présence du flotteur<br>The study of a quayside wave energy converter is proposed. A simplified model composed ofa rectangular buoy oscillating in heave motion and installed close to a vertical dike is developedusing three different models. An analytical model based on potential flow theory is developed inintermediate water depth. A numerical model resolving the Navier-Stokes equation is developed.Experimental tests are performed for different floater dimensions and are used as references for the two other models. The comparison between the three models presents the validity domain of the analytical model. The existence of non-linear effects acting on the floater behaviour is shown.At first, the impact of the system dimensions on the floater behaviour are highlighted and quantified. According to these results a correction of the analytical model is proposed. Moreover, the corrected analytical model is applied to the wave energy converter behaviour. Secondly, the overtoppings are expressed using the wave height between the dike and the floater (provided by analytical model) and the Van Der Meer formula (2002). These overtoppings are also estimated using experimental tests. The comparison of these two models shows the presence of strong load losses when the floater is close to the dike. In those cases the analytical model needs a correction taking into account these load losses. It is also shown that when at the same time the wave length is high and the toe clearance between the dike and the floater is small, the dike overtopping are reduced by the presence of the floater

A la différence de l'apprentissage par mémorisation (rote learning), l'apprentissage significatif (meaningful learning) vise à associer de nouvelles connaissances à des connaissances déjà acquises. La construction de cartes mentales exige et supporte la mise en place de stratégies d'apprentissage significatif, et permet de rendre visible la structure de connaissances de l'apprenant. Cependant, les enseignants qui intègrent la construction de cartes mentales dans leurs activités pédagogiques doivent se contenter du rendu final des cartes mentales, et risquent de faire de mauvaises interprétations et évaluations de celles-ci par manque d'information sur leur processus de construction. Dans cette thèse, nous nous intéressons à l'observation a posteriori de l'engagement de l'apprenant dans ses dimensions comportementale et cognitive, afin de proposer des indicateurs orientés processus qui permettent de comprendre ses actions et ses choix de construction de carte mentale. Nous avons suivi la méthodologie de recherche orientée par la conception (Design Based Research), qui nous a permis de proposer 3 niveaux de contributions : 1) un modèle théorique d'engagement (comportemental et cognitive) pour les activités de construction de cartes mentales, 2) un ensemble d'indicateurs d'engagement de l'apprenant à partir de traces capturées automatiquement lors de la construction de cartes mentales, et 3) un tableau de bord appelé MindMap Monitor présentant différents indicateurs à l'enseignant pour le suivi de la classe et des apprenants. Le modèle a été obtenu à partir d'une étude de littérature sur les théories de l'engagement de l'apprenant issues notamment de la recherche en psychologie de l'éducation. Les indicateurs ont été définis en croisant le modèle avec les résultats de plusieurs études de terrain avec les enseignants. Le tableau de bord implémentant les indicateurs a été construit en trois itérations. Son interface présente des vues synthétiques permettant de comparer les élèves de la classe et d'identifier ceux en difficulté lors de la construction de leur carte, et des vues détaillées décrivant l'activité de construction d'une carte pour chaque élève. Notre tableau de bord a été évalué au cours d'une expérimentation avec 12 enseignants en comparant son utilisation avec celle des cartes mentales finales associées aux vidéos de leur processus de construction. Les résultats montrent que nos indicateurs sur MindMap Monitor permettent de mieux identifier les élèves en difficulté, les difficultés partagées, ainsi que les difficultés pour un élève. Les résultats concernant la compréhension du processus de construction de la carte mentale sont plus nuancés. Nous avons également pu identifier plusieurs pistes d'amélioration sur le contenu du tableau de bord et sa présentation. Les perspectives de notre travail concernent principalement le suivi de l'engagement des apprenants en temps réel pour l'intervention et l'adaptation de la stratégie pédagogique<br>In contrast to rote learning, meaningful learning aims to associate new knowledge with knowledge already acquired. Mind mapping activities require and support the implementation of meaningful learning strategies and enlighten the knowledge structure of the learner. However, teachers who integrate mind mapping into their educational activities have to deal with the final rendering of maps, and risk to misinterpret and wrongly evaluate them due to the lack of information about their construction process. In this thesis, we are interested in a posteriori observation of the engagement of learners along its behavioral and cognitive dimensions, in order to propose processoriented indicators that help to understand actions and construction choices of mind maps. We followed the Design Based Research methodology, that allowed us to propose three levels of contributions : 1) a theoretical model of engagement (behavioral and cognitive) for mind mapping activities, 2) a set of indicators of learner engagement constructed from automatically captured map building traces, and 3) a dashboard called MindMap Monitor presenting various indicators to teachers for class and learners monitoring. The model was obtained from a literature review on theories of engagement, including research in educational psychology. The indicators have been defined by comparing the model with the results of several field studies with teachers. The dashboard implementing the indicators was developed following three iterations. Its interface presents synthetic views allowing the comparison of students in the class, the identification of those in difficulty, and detailed views describing the mind mapping activity for each student. Our dashboard was evaluated with an experiment involving 12 teachers. We compared its use with that of final mind maps associated with videos of their construction process. Results show that our indicators on MindMap Monitor are useful to better identify students in difficulty, shared difficulties, as well as difficulties for individual students. Results concerning the understanding of the mind maps construction process are more balanced. We were also able to identify several ways to improve both the content and the visualizations of the dashboard. The perspectives of our work are mainly related to monitoring learners’ engagement in real time for the intervention and adaptation of the teachers’ educational strategies

Scholars from various disciplines have demonstrated that popular culture factored significantly in Cold War contestation. As a pervasive form of cultural content and unifying medium for baby boomers worldwide, pop music played an important part in the power struggle between the era’s two adversarial camps. Historical studies of the past thirty years have identified initiatives of cultural diplomacy, from radio broadcasting to live concert tours, as key to disseminating Western music in Eastern Bloc societies. This project explains how cultural commerce across the divide of the Iron Curtain familiarized millions of music fans in the German Democratic Republic (GDR) with popular sounds from the United States, the United Kingdom, and other Western democracies. Detailing a process that affected all Bloc states in similar ways, it seeks to enrich the scholarly discourse on the role of pop culture in the twentieth century’s defining ideological conflict. Through analysis of previously unavailable or inaccessible sources, the dissertation reconstructs the economic development of a communist culture industry and measures the commercial significance of Western commodities in one Eastern Bloc marketplace. Drawing on untapped archival files, it traces the evolution of Deutsche Schallplatten (German Records) from a small private firm into a flagship enterprise on the GDR’s cultural circuit. It illuminates how dependency on technology and resources from capitalist countries prompted East Germany’s managers to prioritize the westward export of classical recordings for the purpose of earning hard currencies. Based on oral histories of contemporary witnesses, it documents how the Amiga label through the parent company’s business ties to capitalist partners advanced the import of Western jazz, blues, rock, pop, and dance music to exhaust the purchasing power of the home audience. Empirically evaluating formerly classified production data for a total of 143 million records, it reveals how the state-owned monopolist engineered a de facto takeover of the domestic marketplace by American, British, and West German performers to achieve high profitability. The dissertation argues that intensifying Westernization of its walled-in music market exemplified the GDR’s decision to concede the Cold War battle over cultural preferences and political loyalties of its citizens out of economic necessity.

Nous proposons dans ce mémoire une méthode analytique et expérimentale pour étudier l'interaction fluide-structure dans un réservoir rectangulaire avec une surface libre en présence de gravité lorsque son influence est importante. Plus particulièrement nous nous attacherons au calcul des fréquences et modes propres du système couplé dans le cas particulier d'un problème bidimensionnel, où les mouvements de structure sont perpendiculaires à la direction de la pesanteur. Un potentiel de vitesse du fluide qui satisfait les équations et les conditions aux limites linéarisées est utilisé dans deux configurations pour un solide rigide en mouvement et pour une structure déformable. Dans le cas du solide en mouvement, le couplage avec les ondes de gravité, permet de généraliser le concept de la masse ajoutée classique, et d'étudier les influences de confinement et de la gravité à l'aide de nombre de Froude. Lorsque la paroi verticale du réservoir est modélisée par une poutre, l'évolution des fréquences et modes propres avec le Froude, le niveau de remplissage sont étudiés. Une expérience a été réalisée dans le cas d'une structure souple, et a montré la validité des résultats théoriques. La solution analytique obtenue permettra de valider les codes numériques

A Comparison of Solvent and Water-Borne Alkyd Coatings Abstract Conventional solvent based alkyd coatings have gone out of favor due to concerns over volatile organic compound (VOC) content. However, due to recent focus on renewable raw materials, alkyds are making a comeback in waterborne form. Water based alkyd coatings are known to have poor shelf stability and corrosion resistance, as well as other problems during the formulation process. This project focused on comparing solvent borne to two types of water-borne alkyds, water reducible alkyds and alkyds emulsions. The purpose was to understand the differences between the three types of alkyds in terms of their production and final properties. It was ultimately hoped that the formulations used for this project would prove to solve the problems normally experienced by waterborne alkyds. After testing several chemical and physical properties, it was determined that the solvent borne alkyd coatings performed better than both water based systems in corrosion resistance, accelerated weathering, and shelf stability but the water reducible and emulsion alkyd coatings performed similarly to the solvent borne alkyd in gloss, contrast ratio, and durability. The VOC emissions for all three alkyd types were as expected; the solvent borne had the highest emission at 253 g/L, followed by water reducible with 166 g/L, and emulsion with 34 g/L. The History of VOC Regulations in the United States Abstract In another solvent based alkyd coating focused project within my research group, the question of the how volatile organic compound (VOC) regulation in the United States (U.S.) evolved came up. It quickly became apparent that no comprehensive answer to this question existed. Part two of this project is an attempt to answer this question in a comprehensive manner. VOC regulations started in California in the late 1970s, and paints and coatings became a nationally regulated emission source by the 1990s. The U.S. government limited harmful emissions, such as smog and compounds contributing to ozone depletion, through Clean Air Acts. The first Clean Air Act was enacted in 1965, but it wasn’t until the Clean Air Act of 1990 that VOC emissions became a focus. VOCs are not inherently hazardous but are a source of concern because they serve as a precursor to the formation of damaging ground level ozone. The Environmental Protection Agency (EPA) has established the minimum VOC emission limits in the Architectural and Industrial Maintenance (AIM) federal rule, but each state or state subdivision can enforce stricter limits within their borders. The strictest limits are set by the South Coast Air Quality Management District (SCAQMD) in Southern California, but other entities exist. This report thoroughly documents the history of VOC regulation in the United States by collecting, combining, organizing, and summarizing information gathered from various industries and government publications, agency members, and industrial and academic professionals.

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No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Bruno_Regis_Lyrio_Ferraz.PDF: 3015137 bytes, checksum: d479e9335e2f200939b52075f9b84382 (MD5) Previous issue date: 2016<br>Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)<br>Funda??o de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)<br>RESUMO Etionamida e pirazinamida s?o antibi?ticos ?teis no tratamento da tuberculose multirresistente. O presente trabalho descreve o desenvolvimento e valida??o de metodologias eletroanal?ticas para determina??o de etionamida e pirazinamida em formula??es farmac?uticas e em urina humana empregando um eletrodo de diamante dopado com boro e um eletrodo de carbono v?treo modificado comum filme de poli glicina. Durante o desenvolvimento de ambas as metodologias, a voltametria c?clica foi empregada para verificar a influ?ncia do pH, da velocidade de varredura e do eletr?lito suporte no comportamento eletroqu?mico de ambos os analitos, bem como foram calculados os n?meros de pr?tons e el?trons envolvidos em cada uma das rea??es eletroqu?micas. A voltametria de onda quadrada com os par?metros otimizados foi utilizada para construir curvas anal?ticas para a ETO e PZA. Para a ETO foi obtido um intervalo linear de 1,0 a 80,0 ?mol L?1, com LOD e LOQ iguais a 0,294 e 0,980 ?mol L?1, respectivamente. Para a PZA foi obtido um intervalo linear de 0,47 a 6,16 ?mol L?1, com LOD e LOQ iguais a 0,035 e 0,12 ?mol L?1, respectivamente. A precis?o foi avaliada pelo registro de voltamogramas no mesmo dia e em dias diferentes, obtendo-se desvios padr?es relativos, inferiores a 5,0% em ambos os m?todos. Os resultados dos estudos de interferentes mostraram que nenhuma das subst?ncias testadas interferiu de maneira significativa na determina??o de ambos os f?rmacos. Os m?todos desenvolvidos foram comparados estatisticamente com os protocolos oficiais da farmacopeia atrav?s do teste-t e do teste-F, e os resultados mostraram que os valores de t e F calculados foram menores do que os valores de t e F cr?ticos, indicando que n?o houve diferen?a estat?stica entre as m?dias. A exatid?o de ambos os m?todos foi avaliada tamb?m por estudos de adi??o e recupera??o, obtendo-se como resultados percentuais de recupera??o pr?ximos a 100% para ambos os m?todos. A valida??o das metodologias desenvolvidas foi realizada pela avalia??o dos par?metros anal?ticos como sensibilidade, seletividade, limite de detec??o, limite de quantifica??o, faixa linear, exatid?o e precis?o e os resultados obtidos foram satisfat?rios. Portanto, os m?todos desenvolvidos podem ser aplicados com sucesso na determina??o dos f?rmacos ETO e PZA em medicamentos e urina humana.<br>Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Ci?ncias Farmac?uticas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.<br>ABSTRACT Ethionamide and pyrazinamide antibiotics are useful in the treatment of multidrugresistant tuberculosis. This work describes the development and validation of electroanalytical methodologies for determination of ethionamide and pyrazinamide in pharmaceutical formulation and human urine using boron-doped diamond electrode and poly glycine modified glassy carbon electrode, respectively. During the development of both methodologies, cyclic voltammetry was used to investigate the influence of pH, scan rate and the supporting electrolyte on the electrochemical behavior of both analytes, as well as the numbers of protons and electrons involved in each of the electrochemical reactions were calculated. Square wave voltammetry with optimized parameters were used to construct standard curves for ETO and PZA. For ETO a linear range from 1.0 to 80.0 ?mol L?1 was obtained with LOD and LOQ equal to 0.294 and 0.980 ?mol L?1, respectively. For PZA a linear range from 0.47 to 6.16 ?mol L?1was obtained with LOD and LOQ equal to 0.035 and 0.12 ?mol L?1, respectively. The precision was evaluated by voltammograms record on the same day and on different days, obtaining relative standard deviation less than 5.0% in both methods. The results of interfering studies showed that none of the tested substance interferes significantly in the determination of both drugs. The developed methods were statistically compared with the pharmacopoeia official protocols through the t-test and F-test, and the results showed that the calculated t and F values were lower than the critical t and F values indicating that there was no statistical difference between the averages. The accuracy of both methods was also evaluated by addition and recovery studies, obtaining results as percentage recovery close to 100% for both methods. The validation of the developed methodologies was carried out by the evaluation of analytical parameters such as sensitivity, selectivity, detection limit, quantification limit, linear range, accuracy and precision and the obtained results were satisfactory. Therefore, the developed methods can be applied successfully in the determination of ETO and PZA drugs in pharmaceuticals and human urine.

La thèse a été réalisée dans le cadre d’un partenariat entre le laboratoire d’accueil (C2MA, IMT Mines d’Alès), l’entreprise Renault et un contrat Cifre. La prise de conscience de la dégradation de la qualité de l’air s’étend à tous les environnements, que ce soit à l’intérieur ou à l’extérieur. En Asie, cette prise de conscience se traduit par de très strictes réglementations de la qualité de l’air dans l’habitacle automobile. Les constructeurs se doivent de respecter ces nouvelles réglementations afin de pouvoir vendre leurs véhicules dans ces pays où le marché automobile est en pleine croissance (principalement en Chine). C’est dans ce contexte que Renault a décidé d’améliorer la prise en compte de la qualité de l’air habitacle dans le développement de ses véhicules. Les contraintes techniques et la numérisation des outils de travail ont orienté le travail de thèse vers la modélisation de cette qualité de l’air habitacle. Afin de pouvoir tendre vers cet objectif, plusieurs points ont été traités. Tout d’abord, l’émission des matériaux d’habitacle a été caractérisée afin de comprendre quels composés organiques volatils et quels matériaux étaient responsables de la dégradation de la qualité de l’air dans le véhicule. Ensuite, une nouvelle approche expérimentale a été développée permettant une caractérisation plus représentative de l’émission des matériaux dans l’habitacle. Ces travaux ont permis de confirmer l’importance de l’impact des conditions environnementales sur l’émission des matériaux qui avait été observé dans la littérature. L’étude de ces paramètres environnementaux a été traitée tant dans l’application de modèles présentées dans la littérature que de détermination de facteurs expérimentaux permettant une extrapolation maitrisée de la mesure de l’émission des matériaux à la qualité de l’air dans l’habitacle du véhicule. Enfin, une première méthodologie de modélisation a pu être proposée et appliquée à des systèmes simplifiés permettant de montrer la cohérence de la démarche empruntée<br>The thesis is the result of a partnership between the C2MA (IMT Mines Alès) laboratory and Renault, a car manufacturer, as part of a Cifre contract. The awareness of air quality pollution spread among all indoor or outdoor environments. In Asia, strict regulations about vehicle interior air quality have been released to answer this social realisation. The car manufacturers must fulfil these requirements to be able to market their products in these countries (mainly in China). In these circumstances, Renault decided to improve the way they consider the vehicle interior air quality during the design of the vehicles. The thesis work concerns the modelling of vehicle interior air quality because of the technical obligations and the digitalisation. Different research question came up to follow this objective. First of all, the emission of passenger compartment’s materials has been characterised to understand what Volatile Organic Compounds (VOC) are responsible of the degradation of air quality inside a car and what are the sources. Then, a new characterisation approach of emission has been developed allowing to get a better toughness and representativeness of the results. These studies showed the significance of environmental conditions on the emission ofmaterials that had been studied in the scientific literature. The study of the impact of these environmental factors on the material’s emission was the next step and two different research axes has been explored: the study and development of the modelling available in the literature and the establishment of experimental factors leading to a mastered extrapolation of the characterisation of material’s emission to vehicle interior air quality. Finally, a first methodology has been proposed and applied to simplified systems showing the consistency of the developed process

Le développement de systèmes de propulsion alternatifs aux turboréacteurs actuels constitue un axe de recherche important dans le contexte aéronautique. L’open-rotor, moteur à hélices contrarotatives, constitue une piste sérieuse car il permet à la fois de réduire fortement la consommation de carburant et les émissions de gaz. Toutefois, les émissions sonores restent un défi pour ce type d’architecture, notamment du fait de l’absence de carénage. La compréhension des sources acoustiques et leur prévision est nécessaire afin de pouvoir, par la suite, réduire le bruit de ces moteurs. Les écoulements d’un doublet d’hélices contrarotatives sont complexes, en particulier pour l’hélice aval qui constitue l’axe d’étude de la thèse. Le travail présenté est dédié à une étude numérique, expérimentale et analytique et intervient dans le cadre de la chaire industrielle ADOPSYS entre Safran Aircraft Engines et l’Ecole Centrale de Lyon. L’objectif de ce travail est double. Il s’agit d’une part de réaliser une campagne expérimentale afin d’observer et de mieux comprendre le comportement de l’écoulement et de l’acoustique d’une pale en flèche, notamment en réponse à la présence d’un tourbillon de bord d’attaque. Un second objectif de la thèse était de constituer une base de données afin de comparer les prévisions obtenues avec un modèle analytique. Une méthode de calcul semi-analytique de la réponse aéroacoustique d’une pale aval en réponse à une excitation provenant de l’amont et prenant en compte les effets de charge et de géométrie a été développée. Une étude numérique d’un doublet d’hélices contrarotatives a servi de base à la définition de la géométrie de pale utilisée pendant l’étude. Celle-ci a été définie de façon à observer un tourbillon de bord d’attaque pour certains angles d’incidence. La maquette a ensuite été placée dans une soufflerie anéchoïque de l’Ecole Centrale de Lyon afin de réaliser une étude paramétrique. Des visualisations par enduit visqueux et des mesures de pression pariétale permettent de rendre compte de la présence du tourbillon de bord d’attaque à certains angles d’incidence. L’étude des spectres en champ lointain permet de distinguer un comportement en trois régimes, associés aux trois comportements du tourbillon de bord d’attaque. Des mesures de localisation de sources permettent de corroborer ces observations. Des prévisions analytiques du bruit émis par la pale et se basant sur le modèle d’Amiet ont également été réalisées. Dans un premier temps, les effets de la flèche sont pris en compte dans le modèle et celui-ci est alors appliqué à la pale de l’étude. Une meilleure adéquation des résultats est alors trouvée quand les effets de flèche sont pris en compte, en particulier dans les directions perpendiculaires à la pale. Le modèle est ensuite étendu afin de prendre en compte les effets de la jonction en pied de pale. Cette partie est exploratoire et le développement reste à approfondir. Un complément à l’expérience a consisté en l’étude de l’impact de sillages défilants sur la pale. Un système de barreaux rotatifs permet de générer des sillages périodiques représentatifs d’une interaction de sillages rotor-rotor. Les mesures réalisées montrent le comportement quasi-stationnaire du tourbillon<br>The development of alternative propeller systems to turbojets is a main issue for research in the current context of aeronautical transport. Counter rotating open rotors are a candidate solution because they allow reduction of fuel consumption and gas emission. However, noise emissions are still a challenge for these types of configuration, in particular because they cannot benefit from the nacelle and the liners currently used in turbojet. The understanding of acoustic sources and their prediction is necessary in order to be able to reduce noise emission in the near future. Flows in an open-rotor are complex, in particular for the downstream propeller which is the subject of this approach.This work based on a numerical, experimental and analytical study and takes part in the ADOPSYS chair between Safran Aircraft Engines and l’Ecole Centrale de Lyon. This PhD has two main goals. The first one is to complete an experimental study in order to elucidate the behavior of the flow on a swept airfoil and the resulting acoustics, with a possibly developing leading-edge vortex. The measurements will be a data base for further comparison with analytical prediction. The second objective of the PhD consists in developing a semi-analytical modeling of the noise emitted by an airfoil in response to an incoming perturbation, taking into account the loading and geometry effects. A numerical study of a full counter-rotating system was used as a basis for designing the investigated airfoil. The latter was designed so that a leading-edge vortex could be formed on the surface for some angles of attack. The mock-up was then tested in an anechoic wind tunnel of Ecole Centrale de Lyon for various sets of parameters. Flow visualization and wall-pressure measurements indicated the presence of the leading-edge vortex for some angles of attack. The far-field measurements indicated three acoustic regimes, which can be associated with three behaviors of the leading-edge vortex. Source localization measurements corroborate these observations. Analytical predictions of the noise emitted by the airfoil and based on Amiet’s model were also performed. Firstly, the sweep angle is taken into account in the model. Secondly it is applied to the studied airfoil. A better match of the results is found when the sweep is considered, in particular in the perpendicular directions. The model in then extended in order to include the wall-junction. This part is exploratory and should be further developed. Finally, a complementary experimental investigation of the impingement of periodic wakes on the airfoil has been performed, using a system made of rotating bars, mimics true wake interactions. The measurements suggest that the leading-edge vortex has a quasi-steady behavior

We focused on a non-cooling room temperature microbolometer infrared imaging array device which includes a sensing layer of p-type a-Si:H component layers doped with boron. Boron incorporation and bonding configuration were investigated for a-Si:H films grown by plasma enhanced chemical deposition (PECVD) at varying substrate temperatures, hydrogen dilution of the silane precursor, and dopant to silane ratio using multiple internal reflection infrared spectroscopy (MIR-IR). This study was then confirmed from collaborators via Raman spectroscopy. MIR-IR analyses reveal an interesting counter-balance relationship between boron-doping and hydrogen-dilution growth parameters in PECVD-grown a-Si:H. Specifically, an increase in the hydrogen dilution ratio (H2/SiH4) or substrate temperature was found to increase organization of the silicon lattice in the amorphous films. It resulted in the decrease of the most stable SiH bonding configuration and thus decrease the organization of the film. The new chemical bonding information of a-Si:H thin film was correlated with the various boron doping mechanisms proposed by theoretical calculations. The study revealed the corrosion morphology progression on aluminum alloy (Al, 0.5% Cu) under acidic chloride solution. This is due to defects and a higher copper content at the grain boundary. Direct galvanic current measurement, linear sweep voltammetry (LSV), and Tafel plots are used to measure corrosion current and potential. Hydrogen gas evolution was also observed (for the first time) in Cu/Al bimetallic interface in areas of active corrosion. Mechanistic insight that leads to effective prevention of aluminum bond pad corrosion is explored and discussed. (Chapter 4) Aluminum bond pad corrosion activity and mechanistic insight at a Cu/Al bimetallic interface typically used in microelectronic packages for automotive applications were investigated by means of optical and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electrochemistry. Screening of corrosion variables (temperature, moisture, chloride ion concentration, pH) have been investigated to find their effect on corrosion rate and to better understand the Al/Cu bimetallic corrosion mechanism. The study revealed the corrosion morphology progression on aluminum alloy (Al, 0.5% Cu) under acidic chloride solution. The corrosion starts as surface roughening which evolves into a dendrite structure and later continues to grow into a mud-crack type corrosion. SEM showed the early stage of corrosion with dendritic formation usually occurs at the grain boundary. This is due to defects and a higher copper content at the grain boundary. The impact of copper bimetallic contact on aluminum corrosion was explored by sputtering copper microdots on aluminum substrate. Copper micropattern screening revealed that the corrosion is activated on the Al/Cu interface area and driven by the large potential difference; it was also seen to proceed at much higher rates than those observed with bare aluminum. Direct galvanic current measurement, linear sweep voltammetry (LSV), and Tafel plots are used to measure corrosion current and potential. Hydrogen gas evolution was also observed (for the first time) in Cu/Al bimetallic interface in areas of active corrosion. Mechanistic insight that leads to effective prevention of aluminum bond pad corrosion is explored and discussed. Micropattern corrosion screening identified hydrogen evolution and bimetallic interface as the root cause of Al pad corrosion that leads to Cu ball lift-off, a fatal defect, in Cu wire bonded device. Complete corrosion inhibition can be achieved by strategically disabling the mutually coupled cathodic and anodic reaction cycles.

Deposition of solid state materials span a wide variety of methods and often utilize high energy sources such as plasmas and ultra-violet light resulting in a wide variety of characteristics and applications. A fundamental understanding is essential for furthering the applications of these materials which include catalysis, molecular filtration, electronics, sensing devices, and energy storage among others. A combination of experimental and theoretical work is presented here on several materials including 2D silicates on Pd, boron oxide, and vanadium oxynitride. Silicate formation under low energy electron microscopy demonstrate film permeability to oxygen, while ab initio molecular dynamics simulations reveal the possible initial mechanisms associated with the formation of boron oxide films during atomic layer deposition. Lastly, vanadium oxynitrides have shown preferential sputtering of N over O sites and theoretical binding energies serve as a guide for assigning experimental x-ray photoelectron spectra.

De par leur excellente résolution spatiale et leurs propriétés particulières, les ultramicroélectrodes (UME) constituent des outils de choix pour l'étude de mécanismes biologiques de sécrétion à l'échelle de la cellule unique. En configuration " synapse semi-artificielle ", du fait de la faible distance qui sépare la cellule émettrice de l'UME, les molécules sont libérées dans un faible volume, induisant alors des concentrations suffisamment élevées pour être détectables par électrochimie. Ainsi, les UME offrent la possibiIité de mesurer des flux, même infimes, de molécules électroactives en temps réel. Cette technique analytique a été utilisée, complétée ou adaptée afin d'étudier deux phénomènes biologiques : l'exocytose vésiculaire et le stress oxydant cellulaire. L'analyse ampérométrique de l'exocytose, mécanisme impliqué dans la communication cellulaire, permet l'étude quantitative de la cinétique de libération des molécules intravésiculaires libérées dans le milieu extracellulaire. L'UME, placée dans le milieu extérieur, n'apporte pas d'information quant au statut des vésicules avant la fusion. Pour compléter ces informations, nous avons développé, par des techniques de microfabrication, un microsystème constitué d'électrodes conductrices et transparentes d'ITO permettant un couplage des détections ampérométrique et optique (microscopie TIRF) pour l'étude de la sécrétion des cellules BON BC21. L'ampérométrie à quatre potentiels constants, utilisée au laboratoire pour la détection des ROS/RNS libérées par les macrophages, cellules du système immunitaire, nécessite un grand nombre d'expériences pour s'affranchir de la variabilité cellulaire et des différences de sensibilité des UME. Afin de réduire considérablement le temps d'expérience, nous avons développé un microsystème constitué de quatre chambres de mesure, chacune contenant un jeu de trois électrodes. Ces quatre chambres permettront, à terme, le suivi et la détection simultanée en temps réel des variations de production de H2O2, ONOO-, NO* et NO2- libérées par une cellule.

Le bruit de bord de fuite à large bande est l'un des contributeurs principaux du bruit des soufflantes de turboréacteurs modernes. La double nécessité de mieux comprendre sa génération et de le réduire a suscité le présent travail, essentiellement expérimental. L'étude se focalise sur l'effet de grille provoqué par la diffraction des ondes acoustiques sur les aubes adjacentes. Une grille d'aubes linéaire de solidité 1,43 est instrumentée et adaptée à la mesure acoustique dans le secteur aval pour plusieurs vitesses d'écoulement et plusieurs angles d'attaque. Le bruit de bord de fuite de la grille d'aubes prédomine ainsi sur une large gamme de fréquence. L'effet de grille se manifeste à travers des résonances dans la grille, des interférences dans le champ lointain et à travers la dépendance en vitesse des spectres acoustiques. Les données d'entrée de modèles analytiques décrivant statistiquement la turbulence des couches limites sont directement mesurées sur les aubages. Le modèle de bruit de profil isolé d'Amiet fournit une estimation convenable des niveaux de bruit suggérant que la déformation des spectres par l'effet de grille est de faible amplitude. Nous avons ensuite adapté à la configuration expérimentale le modèle de Glegg qui tient compte des interactions entre pales. Il fournit des estimations de spectres acoustiques s'écartant de 3 dB de la prédiction de profil isolé, confirmant la conclusion précédente. Cependant ce dernier modèle décrit mieux les interférences observées en champ lointain. La réduction du bruit de bord de fuite est ensuite abordée, dans un premier temps sur profil isolé au moyen de brosses insérées au bord de fuite. Une réduction de 4,5 dB est ainsi obtenue sur une large gamme de fréquences. Une étude de corrélation aérodynamique aux fils chauds dans le sillage des brosses montre qu'elles décorrèlent les structures turbulentes dans la direction de l'envergure ce qui peut expliquer partiellement la réduction du bruit observée. Dans un deuxième temps, des chevrons dessinant des dents de scie dans la direction de l'envergure sont appliqués aux bords de fuite de la grille d'aubes. Nous retrouvons alors les observations faites avec ces dispositifs sur les profils isolés. Aucun effet de couplage entre la réduction du bruit et l'effet de grille n'est observé. Des mesures de vélocimétrie par images de particules dans le sillage des chevrons montrent que la couche limite de l'extrados est éloignée de la surface du profil fournissant un mécanisme admissible de réduction du bruit. Un deuxième mécanisme crédible est la décorrélation dans la direction de l'envergure de la nappe de vorticité lâchée dans le sillage suite à la condition de Kutta. Enfin, nous étudions l'effet de l'inclinaison du bord de fuite par rapport 'a l'écoulement et montrons par une prise en compte de cette géométrie dans le modèle d'Amiet qu'il peut également aboutir à une réduction acoustique.

We focused on a non-cooling room temperature microbolometer infrared imaging array device which includes a sensing layer of p-type a-Si:H component layers doped with boron. Boron incorporation and bonding configuration were investigated for a-Si:H films grown by plasma enhanced chemical deposition (PECVD) at varying substrate temperatures, hydrogen dilution of the silane precursor, and dopant to silane ratio using multiple internal reflection infrared spectroscopy (MIR-IR). This study was then confirmed from collaborators via Raman spectroscopy. MIR-IR analyses reveal an interesting counter-balance relationship between boron-doping and hydrogen-dilution growth parameters in PECVD-grown a-Si:H. Specifically, an increase in the hydrogen dilution ratio (H2/SiH4) or substrate temperature was found to increase organization of the silicon lattice in the amorphous films. It resulted in the decrease of the most stable SiH bonding configuration and thus decrease the organization of the film. The new chemical bonding information of a-Si:H thin film was correlated with the various boron doping mechanisms proposed by theoretical calculations. The study revealed the corrosion morphology progression on aluminum alloy (Al, 0.5% Cu) under acidic chloride solution. This is due to defects and a higher copper content at the grain boundary. Direct galvanic current measurement, linear sweep voltammetry (LSV), and Tafel plots are used to measure corrosion current and potential. Hydrogen gas evolution was also observed (for the first time) in Cu/Al bimetallic interface in areas of active corrosion. Mechanistic insight that leads to effective prevention of aluminum bond pad corrosion is explored and discussed. (Chapter 4) Aluminum bond pad corrosion activity and mechanistic insight at a Cu/Al bimetallic interface typically used in microelectronic packages for automotive applications were investigated by means of optical and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electrochemistry. Screening of corrosion variables (temperature, moisture, chloride ion concentration, pH) have been investigated to find their effect on corrosion rate and to better understand the Al/Cu bimetallic corrosion mechanism. The study revealed the corrosion morphology progression on aluminum alloy (Al, 0.5% Cu) under acidic chloride solution. The corrosion starts as surface roughening which evolves into a dendrite structure and later continues to grow into a mud-crack type corrosion. SEM showed the early stage of corrosion with dendritic formation usually occurs at the grain boundary. This is due to defects and a higher copper content at the grain boundary. The impact of copper bimetallic contact on aluminum corrosion was explored by sputtering copper microdots on aluminum substrate. Copper micropattern screening revealed that the corrosion is activated on the Al/Cu interface area and driven by the large potential difference; it was also seen to proceed at much higher rates than those observed with bare aluminum. Direct galvanic current measurement, linear sweep voltammetry (LSV), and Tafel plots are used to measure corrosion current and potential. Hydrogen gas evolution was also observed (for the first time) in Cu/Al bimetallic interface in areas of active corrosion. Mechanistic insight that leads to effective prevention of aluminum bond pad corrosion is explored and discussed. Micropattern corrosion screening identified hydrogen evolution and bimetallic interface as the root cause of Al pad corrosion that leads to Cu ball lift-off, a fatal defect, in Cu wire bonded device. Complete corrosion inhibition can be achieved by strategically disabling the mutually coupled cathodic and anodic reaction cycles.

O ion Co2+, quando coordenado com ligante bipiridina (bipy), pode ser reduzido por ataque químico de redutores fortes, como NaBH4 (boroidreto de sódio), formando [Co(I) (bipy)3]+, azul. Este complexo pode ser determinado espectrofotometricamente por conferir um espectro na região do visível com &#955;max = 600 nm (&#949; = 5,8x103 L.mol-1 .cm-1). Somente cobalto estabiliza-se na forma de [M(i)(bipy)3]+, enquanto que outros metais como Mn, Ni e Zn reduzem-se ao estado metálico. A estabilização do NaBH4 foi conseguida em DMF (N,N´-dimetilformamida). Foi utilizado o método da adição de padrão, condicionando-se o sistema ao meio H20:DMF na proporção de 2:1 (v/v) , T = 25&#176;C, excesso de ligante e excesso de 240 vezes de NaBH4. Níquel interfere acima de 2,5x10-5 mol.L-1 , manganês acima de 5,0x10-5 mol.L-1 e zinco acima de 1,0x10-4 mol.L-1, quando CCO2+ = 5,0x10-5 mol.L-1. Este procedimento foi realizado em amostra NBS167, encontrando-se valores 1% menores que o valor certificado.<br>The cobalt (II) ion complexed with bipyridine (bipy) can be reduced chemically by reductant like sodium boronhydride yelding blue [Co(I)(bipy) 3]+. This complex can be determined spectrophotometrically using visible spectra at &#955; = 600 nm (&#949; = 5,8x103 L.mol-1 . cm-1). When Mn, Ni and Zn are present togheter with cobalt (II) and the mixture is complexed by bipyridine and furtherly treated by boronhydride, the ions of niekel, manganese and zinc are reduced to fundamental state remaining [Co(I)(bipy)3]+ soluble complex. The stabilization of NaBH4 was achieved in N,N\'-dimetilformamide (DMF). Interference studies showed for [Co2+] = 5,0x10-5 mol.L-1, 2:1 of H20:DMF, t = 25&#176;C, excess presence of bipyridine ligand and 240 times excess of NaBH4 : nickel start interfere at 2,5x10-5 mol.L-1, manganese at 5,0x10-5 mol.L-1 and zinc at 1,0x10-4 mol.L-1. The procedure was apllied at a cobalt alloy NBS167 using standard addition method and the recovery was 1% less than certificated value.

The Counter-Rotating Open Rotors (CROR) are identified as a possible alternative to turbofan engines for middle-range aircrafts. Providing significant fuel savings and reducing the green-house gas emissions, they may lead however to an increased noise radiation due to the absence of nacelle shielding. To properly predict the acoustic radiation of such systems is then mandatory both to reduce the source mechanisms of the isolated engine and to offer an optimal noise installation solution. Such an objective is tackled in the present thesis in two steps. In a first part, the research aims at predicting the tonal noise radiated from the first propeller of CROR mounted on the rear fuselage by means of a pylon (pusher configuration), considering both the pylon-wake and the uniform ow effects. From the Ffowcs Williams &amp; Hawkings' formalism, three noise sources are identified. First the unsteady loading is computed using a similar procedure to the one used for the rotor-rotor wake interaction noise prediction. The velocity deficit in the pylon wake is locally expanded in two-dimensional Fourier gusts in a reference frame attached to the front rotor. The unsteady lift induced by each gust on a blade segment is calculated using a linearized analytical response function that accounts for a realistic geometry. The steady loading is the second source contribution and is evaluated using both a software based on the lifting-line theory and some numerical simulations for different reference source surfaces. Finally the thickness noise due to the blade volume displacement is included in the analysis using Isom's formulation. From the linear acoustic assumptions, all these sources modelled as equivalent acoustic dipoles rotating in a uniformly moving atmosphere are then summed to calculate the far-field noise. The whole methodology is assessed against wind-tunnel test data and reference software predictions. A parametric study considering several pylon positionings and pylon-wake configurations with blowing is performed in order to emphasize the relative contribution of the three noise sources. Secondly, the rotor- rotor wake interaction noise being recognized as the most significant contribution in isolated configuration, its modelling is completed by introducing the dynamics of the vortex occurring near the rear-rotor leading edge. A semi-analytical methodology is developed to determine a vortex attached over a at plate embedded in a uniform ow with incidence. Applied to the case of a rear blade going through a front-rotor wake, it provides a first estimate of the noise contribution of the vortex<br>Les hélices contrarotatives constituent une alternative possible aux turboréacteurs pour les avions moyens- courriers. Réduisant significativement la consommation de carburant et les émissions de gaz à effet de serre, ils peuvent néanmoins conduire à un rayonnement sonore accru de par l'absence de carénage. Prédire correctement le rayonnement sonore de telles motorisations est donc indispensable pour réduire les mécanismes sources propres au moteur isolé ou assurer une solution d'installation acoustique optimale. Un tel objectif est abordé dans cette thèse en deux temps. Dans un premier temps, l’étude vise à prédire le bruit tonal rayonné par la première hélice d'un moteur monté à l'arrière du fuselage (configuration dite en pousseur), en considérant les effets du sillage du pylône supportant le moteur et de l'écoulement moyen. Partant du formalisme de Ffowcs Williams &amp; Hawkings, trois sources sonores sont identifiées à cet effet. La charge instationnaire, tout d'abord, est calculée en s'appuyant sur une méthodologie similaire à celle utilisée pour la prédiction du bruit d'interaction de sillages entre les deux rotors. Le déficit de vitesse dans le sillage du mât est décomposé localement en rafales bidimensionnelles dans un repère attaché au rotor amont. La portance instationnaire induite par chaque rafale sur un segment de pale est calculée en utilisant une fonction de réponse analytique linéarisée considérant une géométrie réaliste. Deuxième contribution, la charge stationnaire est évaluée au moyen d'un logiciel s'appuyant sur la théorie de la ligne portante mais également via des simulations numériques pour différentes surfaces sources de référence. Enfin, le bruit d'épaisseur associé au déplacement du volume de la pale est inclus dans l'analyse à partir de la formulation d'Isom. D'après les hypothèses de l'acoustique linéaire, toutes ces sources modélisées comme des dipôles acoustiques tournant dans une atmosphère uniforme en mouvement sont ensuite sommées pour calculer le bruit en champ lointain. L'ensemble de la méthodologie est comparé à des données d'essai et des prédictions d'un logiciel de référence. Une étude paramétrique considérant plusieurs positionnements du pylône et des configurations avec soufflage est effectuée afin de bien mettre en évidence les contributions relatives des trois sources sonores. Dans un deuxième temps, le bruit d'interaction de sillages étant reconnu comme la contribution majoritaire en configuration isolée, sa modélisation est complétée en introduisant la dynamique du tourbillon se développant au voisinage du bord d'attaque du rotor aval. Une méthodologie semi-analytique est développée pour déterminer un tourbillon attaché au-dessus d'une plaque plane plongée dans un écoulement uniforme avec incidence. Appliquée au cas d'une pale aval traversant le sillage du rotor amont, elle fournit une première estimation de la contribution sonore du tourbillon

Les formations à distance en ligne, en particulier les MOOC, voient leurs effectifs augmenter depuis la démocratisation d'Internet. Malgré leur popularité croissante ces cours manquent encore d'outils permettant aux instructeurs et aux chercheurs de guider et d'analyser finement les apprentissages qui s'y passent. Des tableaux de bord récapitulant l'activité des étudiants sont régulièrement proposés aux instructeurs, mais ils ne leur permettent pas d'appréhender les activités collectives, or du point vue socio-constructiviste, les échanges et les interactions que les instructeurs cherchent généralement dans les forums sont essentiels pour les apprentissages (Stephens, 2014). Jusqu'à présent, les études ont analysé les interactions soit sémantiquement mais à petite échelle, soit statistiquement et à grande échelle mais en ignorant la qualité des interactions. La proposition de cette thèse est une nouvelle approche de détection interactive des activités collectives qui prend en compte à la fois leurs dimensions temporelles, sémantiques et sociales. Nous cherchons un moyen de permettre aux instructeurs d'intervenir et d'encourager les dynamiques collectives qui sont favorables pour les apprentissages. Ce que nous entendons par "dynamique collective", c'est l'évolution des interactions à la fois qualitatives et quantitatives, des apprenants dans des forums. Nous nous appuyons sur des études (Boroujeni 2017, Dascalu 2017) qui proposent d'associer l'analyse statistique des interactions et le traitement automatique de la langue, pour étudier les flux d'informations dans les forums. Mais, à la différence des études précédentes, notre approche ne se limite pas à une analyse globale ou centrée sur un individu. Nous proposons une méthode de conception d’indicateurs et de tableaux de bord permettant les changements d'échelles et la personnalisation des vues afin de soutenir les instructeurs et les chercheurs dans leur tâche de détection, d'observation et d'analyse des dynamiques collectives de sous-groupes d'apprenants<br>Massive Open Online Courses (MOOCs) have seen their numbers increase significantly since the democratization of the Internet. In addition, recently with the COVID-19 pandemic, the trend has intensified. If communication devices such as discussion forums are an integral part of the learning activities of MOOCs, there is still a lack of tools allowing instructors and researchers to guide and finely analyze the learning that takes place there. Dashboards summarizing students' activites are regularly offered to instructors, but they do not allow them to understand collective activities in the forums. From a socio-constructivist point of view, the exchanges and interactions sought by instructors in forums are essential for learning (Stephens, 2014). So far, studies have analyzed interactions in two ways: semantically but on a small scale or statistically and on a large scale but ignoring the quality of the interactions. The scientific contribution of this thesis relates to the proposal of an interactive detection approach of collective activities which takes into account their temporal, semantic and social dimensions. We seek to answer the problem of detecting and observing the collective dynamics that take place in MOOC forums. By collective dynamic, we mean all the qualitative and quantitative interactions of learners in the forums and their temporal changes. We want to allow instructors to intervene to encourage these activities favorable to learning. We rely on studies (Boroujeni 2017, Dascalu 2017) which propose to combine statistical analysis of interactions and automatic language processing to study the flow of information in forums. But, unlike previous studies, our approach is not limited to global or individual-centered analysis. We propose a method of designing indicators and dashboards allowing changes of scales and customization of views in order to support instructors and researchers in their task of detecting, observing and analyzing collective dynamics. To support our approach, we set up questionnaires and conducted semi-structured interviews with the instructors. As for the evaluation of the first indicators built at each iteration of our approach, we used various data sources and formats: Coursera (CSV), Hangout (JSON), Moodle (SQL)

Le sol présente une variabilité spatiale des propriétés physiques et mécaniques dont les effets sur des structures légères avec semelles filantes et sur les conduites enterrées ne sont pas bien pris en compte dans leur dimensionnement. Cette variabilité naturelle peut être très importante dans le cas de ces ouvrages car elle induit des tassements différentiels, dont les conséquences peuvent être dommageables : fissures dans les murs, les poutres ou encore des fuites dans les réseaux d'assainissement. La variabilité naturelle du sol et l'incertitude liée à la connaissance imparfaite des propriétés du sol et/ou du béton ou de l'acier de la structure sont les principales sources d'incertitude dans le choix des paramètres de calcul pour le dimensionnement de ces structures. Dans cette thèse, une approche analytique avec les méthodes probabilistes (FOSM et SOSM) et le modèle de Winkler, puis numérique avec le couplage de la méthode des éléments finis avec des approches géostatistiques ont été successivement menées pour modéliser le comportement des semelles filantes et des conduites enterrés lorsque les incertitudes sur les propriétés mécaniques du sol et de la structure sont prises en compte dans leur dimensionnement. Il apparait ainsi, l'importance du comportement longitudinal de ces ouvrages et du poids des incertitudes dans leur dimensionnement.

In forensic chemistry, a quicker and more accurate analysis of a sample is always being pursued. Speedy analyses allow the analyst to provide quick turn-around times and potentially decrease back-logs that are known to be a problem in the field. Accurate analyses are paramount with the futures and lives of the accused potentially on the line. One of the most common methods of analysis in forensic chemistry laboratories is gas chromatography, chosen for the relative speed and efficiency afforded by this method. Two major routes were attempted to further improve on gas chromatography applications in forensic chemistry.<br> The first route was to decrease separation times for analysis of ignitable liquid residues by using micro-bore wall coated open-tubular columns. Micro-bore columns are much shorter and have higher separation efficiencies than the standard columns used in forensic chemistry, allowing for faster analysis times while maintaining the expected peak separation. Typical separation times for fire debris samples are between thirty minutes and one hour, the micro-bore columns were able to achieve equivalent performance in three minutes. The reduction in analysis time was demonstrated by analysis of ignitable liquid residues from simulated fire debris exemplars.<br> The second route looked at a relatively new detector for gas chromatography known as a vacuum ultraviolet (VUV) spectrophotometer. The VUV detector uses traditional UV and far-ultraviolet light to probe the pi and sigma bonds of the gas phase analytes as well as Rydberg traditions to produce spectra that are nearly unique to a compound. Thus far, the only spectra that were not discernable were from enantiomers, otherwise even diastereomers have been differentiated. The specificity attained with the VUV detector has achieved differentiation of compounds that mass spectrometry, the most common detection method for chromatography in forensic chemistry labs, has difficulty distinguishing. This specificity has been demonstrated herein by analyzing various classes of drugs of abuse and applicability to “real world” samples has been demonstrated by analysis of de-identified seized samples.<br>