Thesis (M. Sc.)--Carleton University, 2001. / Includes bibliographical references (p. 84-90). Also available in electronic format on the Internet.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Systems Science and Industrial Engineering, 2007. / Includes bibliographical references (leaves 203-208).

The wetting of a rough material is controlled by surface chemistry and morphology, the liquid phase, solutes, and surfactants that affect the surface tension with the gas phase, and environmental conditions such as temperature and pressure. Materials with high (>150˚) apparent contact angles are known as superhydrophobic and are very resistant to wetting. However, in complex biological mixtures eventually protein adsorbs, fouling the surface and facilitating wetting on time scales from seconds to months. The work here uses the partially-wetted (Cassie-Baxter) to fully-wetted (Wenzel) state transition to control drug delivery and to perform surfactant detection via surface tension using hydrophobic and superhydrophobic materials. First there is an overview of the physics of the non-wetting state and the transition to wetting. Then there is a review of how wetting can be controlled by outside stimuli and applications of these materials. Next there is work presented on controlling drug release using superhydrophobic materials with controlled wetting rates, with both in vitro and in vivo results. Then there is work on developing a sensor based on this wetting state transition and its applications toward detecting solute levels in biological fluids for point-of-care diagnosis. Finally, there is work presented on using these sensors for detecting the alcohol content in wine and spirits.

Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-07-28T13:57:52Z No. of bitstreams: 1 texto completo.PDF: 1092273 bytes, checksum: 61189e2f9ff1c859ecd3bbb9a9959c9a (MD5) / Made available in DSpace on 2017-07-28T13:57:52Z (GMT). No. of bitstreams: 1 texto completo.PDF: 1092273 bytes, checksum: 61189e2f9ff1c859ecd3bbb9a9959c9a (MD5) Previous issue date: 2002-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Um sistema de medição e controle foi desenvolvido para o estudo de respostas fisiológicas de aves sujeitas a mudanças térmicas como meio de alívio de estresse térmico. O sistema faz o controle automático da temperatura (t a,SP ±0,2 oC) e da umidade relativa do ar (RH SP ±2 %); sendo que a velocidade do ar foi controlada manualmente (V SP ±0,1 m· s -1 ); e contínuo armazenamento das termografias (ex., temperatura superficial, t surf ) e da temperatura corporais (t b ) dos animais. As condições térmicas controladas na zona de ocupação animal (AZO) são atingidas pela operação de um pequeno túnel de vento (V = 0 to 1,5 m· s -1 ) colocado no interior de uma sala ambiental com t a e RH controlados (5,0 m comprimento × 3,5 m largura × 3,0 m altura). Os valores desejados de t a e RH foram alcançados por meio de aquecedores e umidificadores controlados em dois estágios via um módulo de controle e medição programável, e periféricos. Termografias (discernabilidade de 0.06°C) são adquiridas com uma camera infravermelho cuja operação é controlada remotamente por um PC. t b (±0.1°C) é armazenado em uma unidade de telemetria, sem a necessidade de intervenção cirurgica, que também é conectado a um PC. Em adição, um sistema de video tem sido usado para observar e arquivar os comportamentos do animal. A instrumentação desenvolvida foi usada em um experimento para ajustar equações empíricas para descrever as necessidades de molhamento parcial da superfície em galinhas poedeiras (Hy-Line W98, com 34 ± 1 semanas) sujeitas a condições de estresse térmico. A água necessária para limitar o aumento da temperatura superficial das galinhas foi expressada em termos de intervalo de aspersão (SI 10 , min) para uma dosagem constante (10 ml· aspersão -1 ) ou para uma taxa de evaporação (ER, ml.min -1 ) de água aspergida. As exposições térmicas consistiram de uma combinação fatorial de 3 temperaturas de bulbo seco (t db ) (35, 38 e 41 °C) x 2 temperaturas de ponto de orvalho (t dp ) (21,1 e 26,7 °C) x 3 velocidades do ar (V) (0,2, 0,7 e 1,2 m· s -1 ). As condições ambientais foram expressas como 18 combinações de déficit de vapor de pressão do ar (VPD air ) x V. ER foi diretamente proporcional ao produto VPD air · V . As relações podem servir como a base para a otimizar o sistema de resfriamento superficial intermitente para alívio de estresse térmico em galinhas criadas em gaiolas. Ademais, um índice de desconforto térmico (TDI) foi derivado com base nas respostas fisiológicas, temperatura superficial (t surf ) e temperatura corporal (t b ), de galinhas sujeitas a exposições térmicas. Com base no aumento da t b aos 50 min de exposição térmica (Δt b,50 ), um TDI foi relacionado ao VPD air e a V da seguinte forma: TDI = -15.17 + 18.62 (t db ) n – 0.92 · (VPD air · V ) n . Usando TDI, quatro zonas de desconforto térmico (segura, alerta, perigo e fatal) foram definidas para as várias combinações de condições térmicas. Um modelo teórico de transferência de calor e massa em regime transiente também foi proposto para predizer Δt b,50 em função das condições ambientais, das condições fisiológicas das aves e do nível de molhamento (β). O modelo proporciona uma ferramenta conveniente e interativa para determinar Δt b,50 nas galinhas submetidas ou não ao molhamento superficial para t db variando de 35 a 38 °C. / A control and measurement system was developed for studying physiological responses of poultry to thermal challenges and means of thermal stress relief. The system features automatic control of air temperature (t a,SP ±0.2 oC) and relative humidity (RH SP ± 2 %); manual setting of air velocity (V SP ± 0.1 m· s -1 ); and continuous recording of thermographs (i.e., core body temperature (t b ) of the animal. surface temperature, t surf ) and The controlled thermal conditions in the animal-occupied zone (AOZ) are achieved through operation of a small wind tunnel (V = 0 to 1.5 m· s -1 ) inside a t a - and RH-controlled environmental room (5 m L × 3.5 m W × 3.0 m H). Target t a and RH values are achieved by controlling auxiliary heaters and humidifiers in two stages via a programmable measurement and control module and peripherals. Thermographs (0.06°C discernability) are acquired with an infrared (IR) imager whose operation is remotely controlled by a PC. Core body temperature (t b , ±0.1°C) is recorded with a surgery-free telemetric sensing unit that is also interfaced with a PC. In addition, a video monitoring system is used to observe and archive animal behaviors. The instrumentation developed was used in an experiment to establish empirical equations to describe the need of partial surface wetting for cooling laying hens (Hy-Line W-98, 34 ±1 wk old) subjected to a range of thermal stress conditions. The thermal exposures consisted of a factorial combination of 3 dry bulb temperatures (t db ) (35, 38 and 41 °C) × 2 dew point temperatures (t dp ) (21.1 and 26.7 ° C) × 3 air velocities (V) (0.2, 0.7 and 1.2 m· s - ). The environmental conditions were expressed as 18 combinations of air vapor pressure deficit (VPD air ) × V. The water necessary to limit hen surface temperature from rising was expressed in terms of sprinkle interval (SI 10 , min) for a constant spray dosage (10 ml· spray -1 ) or evaporation rate (ER, ml· min -1 ) of the sprayed water. ER was directly proportional to VPD air · V . The relationships may serve as the basis for optimizing an intermittent partial surface cooling system for thermal stress relief of caged layers. Also from the study, a thermal discomfort index (TDI) was derived based on physiological responses, surface temperature (t surf ) and core body temperature (t b ) of the control (non-cooled) hens. Based on t b rise after 50 min of thermal exposure (Δt b,50 ), TDI related to VPD air and V as: TDI = -15.17 + 18.62 (t db ) n – 0.92· (VPD air · was V ) n . Using TDI, four zones of thermal discomfort (safe, alert, danger, and fatal) were defined for various combinations of thermal conditions. Furthermore, theoretical transient heat and mass transfer model was proposed to predict Δt b,50 as a function of environmental conditions, physiological responses of the hens and surface wetness level (β). The model provides a convenient, interactive tool for determining Δt b,50 on wetted and non-wetted hens for t db ranging from 35 to 38 °C.

PINHEIRO, Daniel Gurgel. Molhamento da carga como método de atenuação do estresse térmico durante o transporte de frangos vivos. 2015. 107 f. Dissertação (Mestrado em Engenharia Agrícola)-Universidade Federal do Ceará, Fortaleza, 2015. / Submitted by Vitor Campos (vitband@gmail.com) on 2016-10-13T22:57:28Z No. of bitstreams: 1 2015_dis_dgpinheiro.pdf: 3175606 bytes, checksum: e7e9eee6e7d0b1cb4f4cf57119909cca (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-10-13T23:14:57Z (GMT) No. of bitstreams: 1 2015_dis_dgpinheiro.pdf: 3175606 bytes, checksum: e7e9eee6e7d0b1cb4f4cf57119909cca (MD5) / Made available in DSpace on 2016-10-13T23:14:57Z (GMT). No. of bitstreams: 1 2015_dis_dgpinheiro.pdf: 3175606 bytes, checksum: e7e9eee6e7d0b1cb4f4cf57119909cca (MD5) Previous issue date: 2015 / The load wetting is a widely practice used in poultry production during the pre-slaughter loading and carrying operations. According to most producers, the practice of wetting is a way to release the stress of the chickens and minimize production losses. Several studies developed in the ambience of the area have focused their attention on pre-slaughter fasting operations, capture, loading, transportation and waiting. The wetting, however, is only mentioned as a widespread practice and it was not found, however, any analysis that proves its benefit. Thus, the aim of this study was to evaluate the efficiency of cargo wetting to reduce thermal stress. For this aim, they were measured the temperature and the relative humidity, with the help of meteorological mini-stations (Data Logger), and it was calculated the enthalpy of Comfort Index (IEC), to characterize the environments where there were pre-slaughter operations. For the bioclimatic characterization (microclimate) of the load, it was carried out the analysis of the temperature distribution of the boxes located in the outer parts (right, left, top and back) by thermography (thermal imagers). Concerning the boxes located in the center of the load, where it was not possible to use the Imager, they were used eighteen data loggers, thus distributed in strategic boxes, as a record, at every minute, of the temperature and relative humidity for subsequent calculation of the IEC. It as also performed, with the help of geostatistical techniques (kriging maps), the spatial determination of temperature, relative humidity and IEC during observations with and without load wetting. There was also an attempt to determine the thermal sensation of the load during the trip of the chickens located on the right side, on the left side and on the top of the load, with the help of three thermoanemometers to record, at every minute, the temperature and wind speed and, to calculate the real comfort sensation, we used the equation of equivalent temperature Wind Chill. The approach of this work emphasizes the use of IEC and enthalpy tables, and the use of the t hypothesis testing to verify the claim that there would be no difference between the means of the IEC load of wet and dry cargo in the region with the worst heat dissipation situation (central row) during transport. The results have shown that the load wetting was not effective in alleviating the thermal stress during transportation. It can also be perceived that the use of thermography as a thermal diagnostic tool, as well as studies for modeling an equation that might represent the wind chill of the chickens, depending on the temperature and wind speed, is of great importance for the design of vehicles to transport live load. / O molhamento da carga é uma prática muito utilizada na avicultura de corte, durante as operações pré-abate de carregamento e transporte. Segundo a maioria dos produtores, a prática do molhamento é uma forma de amenizar o estresse das aves e minimizar as perdas produtivas. Vários trabalhos desenvolvidos na área de ambiência focaram suas atenções nas operações pré-abate de jejum, captura, carregamento, transporte e espera. O molhamento, porém, é apenas citado como uma prática muito difundida, não constando, no entanto, nenhuma análise que comprove o seu benefício. Sendo assim, o objetivo deste trabalho foi avaliar a eficiência do molhamento da carga na redução do estresse térmico. Para isso, foram medidas a temperatura e a umidade relativa, com o auxílio de miniestações meteorológicas (Data Logger), e calculado o Índice Entalpia de Conforto (IEC), para a caracterização dos ambientes onde ocorreram as operações pré-abate. Para a caracterização bioclimática (microclima) da carga, foi realizada a análise da distribuição da temperatura das caixas localizadas nas partes externas (lateral direita, esquerda, topo e traseira) através da termografia (termovisores). As caixas localizadas no centro da carga, onde não foi possível o usar o termovisor, foram utilizados dezoito Data Loggers, distribuídos em caixas estratégicas para o registro, a cada minuto, da temperatura e umidade relativa, para posterior cálculo do IEC. Procedeu-se, ainda, com a ajuda de técnicas de geoestatística (mapas de Krigagem), a determinação espacial da temperatura, umidade relativa e IEC durante as observações com e sem o molhamento da carga. Também se tentou determinar a sensação térmica durante a viagem dos frangos localizados nas laterais direita, esquerda e topo da carga, com a ajuda de três termoanemômetros para registro, a cada minuto, da temperatura e velocidade do vento e, para o cálculo da real sensação de conforto, foi utilizada a equação da temperatura equivalente de Wind Chill. A abordagem deste trabalho dá ênfase ao uso do IEC e das tabelas de Entalpia, além do uso do teste de hipóteses t para verificar a afirmação de que não haveria diferença entre as médias do IEC da carga molhada e da carga seca, na região que apresenta a pior situação de dissipação do calor (fileira central) durante o transporte. Os resultados mostraram que o molhamento da carga não se mostrou eficiente em amenizar o estresse térmico durante o transporte. Pode-se ainda constatar que o uso da termografia como ferramenta de diagnóstico térmico, assim como estudos para a modelagem de uma equação que retrate a sensação térmica da ave em função da temperatura e velocidade do vento, é de suma importância para o projeto de veículos de transporte de carga viva.

Les mécanismes d'interaction entre une interface fluide et une paroi solide en situation de mouillage sont encore des problèmes ouverts. Parmi les nombreuses interrogations traitées dans la littérature, le "problème de la ligne de contact en mouvement" est très étudié depuis les années 1970, lorsque le paradoxe lié au mouvement de la ligne de contact a été identifié. En quelques mots ce paradoxe est le suivant : les modèles hydrodynamiques macroscopiques utilisant une condition de non-glissement à la paroi prédisent un cisaillement infini au niveau de la ligne de contact. Des études prometteuses pour aborder ce problème se sont appuyées sur des résultats fournis par les simulations dynamiques moléculaires. Elles confirment la présence de glissement au niveau de la ligne de contact. Malheureusement, les simulations de type dynamique moléculaire sont limitées à de très petites échelles à la fois temporelles et spatiales de sorte que les modèles hydrodynamiques et les simulations numériques des équations de Navier-Stokes restent nécessaires. Dans ce type de simulation, la méthode Continuum Surface Force pour traiter le terme capillaire entraine une vitesse et un cisaillement au niveau de la ligne de contact dépendant de la résolution, problème qui est abordé dans ce travail. L'écoulement au voisinage de la ligne de contact est analysé théoriquement dans la limite des écoulements de Stokes et l'effet des conditions limites à la paroi est exploré. Une des conditions proposées dans la littérature permet de lever la divergence du cisaillement et rend possible l'observation de tourbillons de Moffatt au voisinage de la ligne de contact ce qui reste encore à observer que ce soit expérimentalement ou numériquement. Cette possibilité est explorée de manière théorique puis numérique à l'aide du code JADIM. Sur le plan numérique, la présence de courants parasites est apparue comme limitante si la méthode VoF est utilisée. Pour remédier à cet obstacle numérique, une version très prometteuse de la méthode front-tracking utilisant des markers Lagrangien a été implémentée et améliorée pour permettre de traiter des distributions nonuniformes de markers sans perdre les performance de réduction significative des courants parasites. De nombreux tests ont été réalisés pour valider la méthode développée et montre la réduction à la précision machine des courants parasites. La méthode est également validée pour la simulation des lignes de contact statiques et dynamiques avant d'être utilisée pour l'étude de tourbillons induits par la mise en mouvement d'une ligne de contact. Finalement, s'appuyant sur les développements théoriques de ce travail, un nouveau modèle de sous maille est proposé pour permettre la simulation de lignes de contact aux échelles macroscopiques. Il est implémenté dans la nouvelle méthode front-tracking introduite dans JADIM. Les premiers résultats montrent une amélioration partielle de l'effet du maillage sur la vitesse de la ligne de contact mais une maitrise totale du cisaillement. Les simulations de l'étalement de gouttes permet de retrouver de manière très satisfaisante les résultats théoriques et expérimentaux de référence. / The exact mechanism with which a fluid interface interacts dynamically with a solid surface during wetting is still open to research. Among the many subjects addressed in this field in the literature, the "moving contact line problem" is one that has been ubiquitous since at least the 1970s, where a paradox in the description of the contact line was found to exist. The paradox in a few words is the next: macroscopic hydrodynamic models using the no-slip boundary condition will predict infinite shear stress close to the contact line. The most promising studies to tackle the problem come from information provided by molecular dynamics simulations. They have confirmed that close to the contact line, the no-slip boundary condition is relaxed to some form of slip. Unfortunately, molecular simulations are still limited to very small scales in space and time, so hydrodynamic models and numerical simulations based on Navier-Stokes equations are still needed. In these simulations, the Continuum Surface Force model CSF for the calculation of the capillary contribution introduces a grid dependent contact line velocity and shear at the wall, which is a problem we proposed to solve here. In this work, we analyze the flow close to the moving contact line in the context of corner stokes-flow and explore the effects of the boundary conditions at the wall. One of these conditions offered in the literature, provides relief to the shear divergence and also opens the possibility to observe Moffatt vortices in the vicinity of the contact line, not yet seen in experiments or numerical simulations. We explore this possibility analytically and then numerically using the code JADIM. The latter task is constrained by the contamination of the velocity field by the so-called spurious velocities if the VOF method is used. To solved this inconvenient, a very promising version of the front-tracking method with lagrangian markers is implemented and enhanced to handle non-uniform distribution of markers without losing its spurious velocities elimination features. Numerical tests are conducted to validate the implementation, spurious velocities are reduce close to machine precision and comparison to benchmark data is performed obtaining good agreement. Tests including contact lines are then compared with exact solutions for shape analyzing the effect of the Bond number, showing remarkable results. Numerical experiments with this implementation close to a contact line show the existence of vortical patterns during of spreading. Finally, and based on the theoretical background developed in this work, a new sub-grid model method is proposed for macroscopic numerical simulations and implemented in the new front-tracking method of JADIM. Quantitative data is obtained and compared to numerical and experimental spreading cases revealing improvement of grid convergence and excellent agreement.

Les mécanismes dynamiques et de transport mis en jeu dans le plasma d'arc et le bain de fusion d'une opération de soudage à l'arc sont nombreux et fortement couplés. Ils produisent un milieu dont les grandeurs présentent des variations temporelles rapides et des gradients très marqués qui rendent toute analyse expérimentale complexe dans cet environnement fortement perturbé. Dans ce travail, on s'intéresse aux procédés TIG et MIG. Une plateforme expérimentale a été développée pour permettre la mesure synchronisée de différentes grandeurs physiques associées au soudage (paramètres procédé, températures, efforts de bridages, transferts métalliques, etc.). Des librairies numériques dédiées aux études appliquées au soudage à l'arc sont également développées. Elles permettent le traitement de flux important de données (signaux, images) de manière systématique et globalisée. L'intérêt de cette approche pour l'enrichissement de la simulation numérique et le contrôle des procédés à l'arc est illustré dans différentes situations. Enfin, cette approche expérimentale est utilisée, dans le cadre de l'application choisie, pour obtenir des mesures suffisamment riches pour décrire le comportement dynamique du bain de fusion en P-GMAW. Une analyse dimensionnelle de ces mesures expérimentales permet d'identifier les mécanismes prépondérants qui interviennent et de déterminer expérimentalement les temps caractéristiques associés. Ce type d'approche permet notamment de mieux décrire le comportement d'une macro-goutte de métal fondu ou les phénomènes intervenant dans les problèmes de humping. / The dynamic and transport mechanisms involved in the arc plasma and the weld pool of arc welding operationsare numerous and strongly coupled. They produce a medium whose magnitudes exhibit rapid time variations and gradients very marked which make any experimental analysis complex in this disrupted environment. In this work, we study the TIG and MIG processes. An experimental platform was developed to allow synchronized measurement of various physical quantities associated with welding (process parameters, temperatures, clamping forces, metal transfer, etc.). Numerical libraries dedicated to applied studies in arc welding are developed. They allow to treat large flow of data (signals, images) in a systematic and global method. The advantages of this approach for the enrichment of numerical simulation and arc process control are shown in different situations. Finally, this experimental approach is used in the context of the chosen application, to obtain rich measurements to describe the dynamic behavior of the weld pool in P-GMAW. Dimensional analysis of these experimental measurements allows to identify the predominant mechanisms involved and determine experimentally the characteristic times associated. This type of approach includes better describe for the behavior of a macro-drop of molten metal or the phenomena occurring in the humping instabilities.

abstract: Gallium-based liquid metals are of interest for a variety of applications including flexible electronics, soft robotics, and biomedical devices. Still, nano- to microscale device fabrication with these materials is challenging because of their strong adhesion to a majority of substrates. This unusual high adhesion is attributed to the formation of a thin oxide shell; however, its role in the adhesion process has not yet been established. In the first part of the thesis, we described a multiscale study aiming at understanding the fundamental mechanisms governing wetting and adhesion of gallium-based liquid metals. In particular, macroscale dynamic contact angle measurements were coupled with Scanning Electron Microscope (SEM) imaging to relate macroscopic drop adhesion to morphology of the liquid metal-surface interface. In addition, room temperature liquid-metal microfluidic devices are also attractive systems for hyperelastic strain sensing. Currently two types of liquid metal-based strain sensors exist for inplane measurements: single-microchannel resistive and two-microchannel capacitive devices. However, with a winding serpentine channel geometry, these sensors typically have a footprint of about a square centimeter, limiting the number of sensors that can be embedded into. In the second part of the thesis, firstly, simulations and an experimental setup consisting of two GaInSn filled tubes submerged within a dielectric liquid bath are used to quantify the effects of the cylindrical electrode geometry including diameter, spacing, and meniscus shape as well as dielectric constant of the insulating liquid and the presence of tubing on the overall system's capacitance. Furthermore, a procedure for fabricating the two-liquid capacitor within a single straight polydiemethylsiloxane channel is developed. Lastly, capacitance and response of this compact device to strain and operational issues arising from complex hydrodynamics near liquid-liquid and liquid-elastomer interfaces are described. / Dissertation/Thesis / Masters Thesis Materials Science and Engineering 2015

abstract: Design and mitigation of infrastructure on expansive soils requires an understanding of unsaturated soil mechanics and consideration of two stress variables (net normal stress and matric suction). Although numerous breakthroughs have allowed geotechnical engineers to study expansive soil response to varying suction-based stress scenarios (i.e. partial wetting), such studies are not practical on typical projects due to the difficulties and duration needed for equilibration associated with the necessary laboratory testing. The current practice encompasses saturated “conventional” soil mechanics testing, with the implementation of numerous empirical correlations and approximations to obtain an estimate of true field response. However, it has been observed that full wetting rarely occurs in the field, leading to an over-conservatism within a given design when partial wetting conditions are ignored. Many researchers have sought to improve ways of estimation of soil heave/shrinkage through intense studies of the suction-based response of reconstituted clay soils. However, the natural behavior of an undisturbed clay soil sample tends to differ significantly from a remolded sample of the same material. In this study, laboratory techniques for the determination of soil suction were evaluated, a methodology for determination of the in-situ matric suction of a soil specimen was explored, and the mechanical response to changes in matric suction of natural clay specimens were measured. Suction-controlled laboratory oedometer devices were used to impose partial wetting conditions, similar to those experienced in a natural setting. The undisturbed natural soils tested in the study were obtained from Denver, CO and San Antonio, TX. Key differences between the soil water characteristic curves of the undisturbed specimen test compared to the conventional reconstituted specimen test are highlighted. The Perko et al. (2000) and the PTI (2008) methods for estimating the relationship between volume and changes in matric suction (i.e. suction compression index) were evaluated by comparison to the directly measured values. Lastly, the directly measured partial wetting swell strain was compared to the fully saturated, one-dimensional, oedometer test (ASTM D4546) and the Surrogate Path Method (Singhal, 2010) to evaluate the estimation of partial wetting heave. / Dissertation/Thesis / Masters Thesis Engineering 2017

Dans ce travail, nous avons étudié certains aspects fondamentaux (i) du mouillage, (ii) de germination aux interfaces réactives et au sein de la brasure et (iii) de la cinétique de croissance de couches intermétalliques au cours de l'assemblage par brasage en électronique (système Cu/liquide Sn).Le mouillage de Cu, Ag et de leurs composés avec Sn (Cu3Sn, Cu6Sn5 et Ag3Sn) par les brasures liquide Sn-Cu a été étudié par la technique de la goutte déposée dans un four à vide et suivi d'une caméra rapide. Dans la gamme de températures 300-6000C, la première étape de mouillage a lieu en moins de 10 ms et la vitesse d'étalement est d'environ 0.25 m.s-1. Au cours de cette étape (étalement non réactif) la cinétique d'étalement est pratiquement indépendante de T et similaire à celui non réactif du Pb liquide sur Cu. L'angle de contact d'équilibre de Sn liquide sur une surface non-réagi de Cu est inférieur à 300. Les angles de contact non réactifs sur Cu3Sn, atteints en moins de 10 ms, diminuent de 23 à 100 lorsque T augmente de 300 à 5000C. Au cours du mouillage sur Cu6Sn5 à 3900C, de faibles angles de contact (200) sont atteints en moins de 10 ms. Les résultats des expériences de mouillage sur Ag et Ag3Sn ont permis de proposer un mécanisme d'étalement en deux étapes: une première étape de mouillage non réactif très rapide et une seconde de mouillage réactif lente.En mettant en œuvre un dispositif expérimental d'immersion rapide et les techniques de TEM et SEM-FEG, nous avons réussi à étudier, pour la première fois, la séquence de formation des intermétalliques à l'interface Cu/alliage liquide au début de la réaction (1 ms à 1 s) à 2500C. Ces expériences donnent, pour la première fois, la réponse à une des questions les plus ouvertes et intéressantes concernant le brasage en électronique: la première phase qui se forme à l'interface Cu/Sn liquide est Cu6Sn5. Ensuite, nous avons développé une approche théorique sur les critères de suppression de la seconde phase (Cu3Sn) en supposant que Cu6Sn5 est la première qui se développe à l'interface sous forme d'une couche continue. Par ailleurs une modélisation théorique des étapes antérieures, lorsque la germination d'un embryon isolé de Cu3Sn se développe, est proposé.La cristallisation de l'alliage eutectique Sn-Cu a été étudiée par DSC en appliquant des cycles thermiques de fusion complète et partielle. Différentes catégories de degrés de surfusion ont été obtenues. En particulier, des degrés de surfusion faibles (1-7K) ont été détectés pour la première fois dans le cas de la fusion partielle. Une approche théorique sur la nucléation hétérogène est développée et les sites responsables de la germination ont été proposés.La comparaison directe de la cinétique de croissance dans le couple standard Cu/Sn liquide et celui incrémental Cu3Sn5/Sn liquide nous a permis de proposer un mécanisme de croissance de Cu6Sn à l'interface de Cu/Sn liquide. Les résultats obtenus sont compatibles avec le modèle FDR.Des expériences spécifiques de réactions interfaciales entre Cu et l'alliage liquide métastable Sn-0.7wt.%Cu à 2220C et pour des temps de réaction aussi long que 32 h ont été effectuées pour la première fois. Ceci est réalisé par des expériences spécifiques de DSC afin de contrôler l'état physique de l'alliage et la température. La comparaison directe des cinétiques de croissance et de la morphologie des couches réactionnelles formées entre les couples Cu/liquide et Cu/solide, à la même température, a conduit à la conclusion suivante: la grande différence de cinétique de croissance est due à la diffusion à l'état liquide par l'intermédiaire des canaux liquide de largeur nanométrique formés entre les joints de grains de Cu6Sn5 et/ou par des canaux cylindriques de rayon de quelques dizaines de nm formées aux joints triples des grains de Cu6Sn5. Une évaluation théorique de la largeur de ces canaux est effectuée pour la première fois et son évaluation est cohérente avec le modèle FDR. / In this work we have studied some fundamental aspects of (i) wetting, (ii) nucleation at reactive interfaces as well as inside the solder bulk and (iii) growth kinetics of intermetallic layers during a soldering process in electronic industry (Cu/liquid Sn system).Wetting of metallic substrates Cu, Ag and their intermetallics with Sn (Cu3Sn, Cu6Sn5 and Ag3Sn) by liquid Sn-Cu solders was studied by the dispensed drop technique in a high-vacuum furnace and using a rapid camera for recording the spreading process. In temperature range 300-600C, the first stage of wetting of Cu by liquid alloy occurs in less than 10ms and the spreading rate is about 0.25 m.s-1. During this stage (non reactive spreading) the spreading kinetics is practically temperature independent and similar to that of the non-reactive liquid Pb on Cu. The equilibrium contact angle of liquid Sn on a non-reacted and clean surface of Cu is lower than 300. The non-reactive contact angles on Cu3Sn, attained in less than 10 ms, decrease from 23 to 100 when T increases from 300 to 500C. During wetting of Cu6Sn5 at 390C, low contact angle of about 20 are attained in less than 10 ms. Results of wetting experiments of Ag and Ag3Sn substrates allowed to propose a mechanism of the spreading kinetics in two stages: a very rapid non reactive wetting and a slow reactive wetting stage.By implementing a fast dipping experimental set-up and SEM-FEG and TEM techniques, we succeed to study for the first time the sequence of formation of intermetallics at the Cu/liquid alloy interface at the very beginning of reaction (1 ms to 1 s) at 250C. These experiments give, for the first time, the answer to one of the most challenging questions in soldering: the first phase that appears at Cu/liquid Sn interface is the Cu6Sn5 phase. Afterwards, we developed a theoretical approach on the suppression criteria of the second phase formation (Cu3Sn) by assuming that Cu6Sn5 is the first phase that grows at the interface in form of a continuous layer. Moreover, a theoretical modeling of even earlier stages of the isolated nucleus of Cu3Sn phase nucleation is developed.Crystallization of eutectic Sn-Cu alloy was studied by performing specific DSC experiment by applying thermal cycles of complete and partial melting of the solder. Different categories of the undercooling degrees are obtained. In particular, low undercooling degrees (1-7K) are detected for the first time in the case of partial melting. A theoretical approach on heterogeneous nucleation is developed and the responsible sites of nucleation in the case of low undercooling degrees are proposed.Direct comparison of Cu6Sn5 growth kinetics in standard Cu/liquid Sn and in incremental Cu3Sn/liquid Sn couple gave a link with the operating mechanism of the Cu6Sn5 phase growth at solid Cu/liquid Sn interface. The obtained results are also consistent with the FDR model.Specific experiments dealing with interfacial reactions between Cu substrate and metastable liquid Sn-0.7wt.%Cu alloy at 222°C for reaction times as long as 32 h were performed for the first time. This is achieved by performing specific DSC experiments in order to monitor and control the physical state of the alloy as well as to set the accurate reaction temperature. Direct comparison of Cu/liquid and Cu/solid solder growth reaction kinetics and layer morphology at the same temperature lead to the conclusion that the large difference in the growth kinetics between the two couples can be explained if the growth occurs by the liquid state diffusion via the liquid channels of nanometric width formed between grain boundaries of Cu6Sn5 phase and/or by cylindrical channels of radius of some tens of nanometers formed at the triple line junctions of Cu6Sn5 scallops. A theoretical evaluation of the liquid channel width is performed for the first time. Evaluation is consistent with the FDR model.