This paper presents the results of an ongoing effort to develop a direct solder bumping process for electronics packaging. The proposed process entails delivering molten droplets onto specific locations on electronic devices to form solder bumps. This study is focused on investigating droplet deposition behaviors that affect solder bump characteristics such as final bump volume, shape, and adhesion strength. The occurrence of droplet bouncing has a strong influence on these characteristics. The potential for a droplet to bounce in the absence of solidification was modeled in discrete stages based on energy conservation. Wetting and target surface roughness were identified as the critical parameters affecting bouncing. The experimental results showed that improvements in wetting and decreases in surface roughness retard bouncing. These observations agreed well with the trends predicted by the energy conservation based model. The knowledge acquired in this study is expected to contribute to the development of an efficient solder bumping process. / Singapore-MIT Alliance (SMA)

Introduced in 1991, solid ink color printing technology is widely used in the office printing, prepress proofing, and wide format color printing markets. Ink droplets are first deposited on a rotating drum and then transferred to paper to reproduce images with high print quality. The objective of this thesis is to develop scientific knowledge of ink droplet deposition, which is needed for precise image buildup on the drum surface. The first problem studied in the thesis is droplet formation from the printhead with varied working voltages and jetting frequencies. Attention is paid to the formation of satellite droplets, the contraction of ligaments and the startup of high frequency jetting. The jetting conditions for obtaining consistent droplet generation with satellites are determined. A theoretical model is developed to predict the lifetime of ligaments. The second problem we studied is the deposition of single droplets on solid surfaces. The surface texture and final shape of deposited droplets are correlated with impact conditions, which include printhead temperature, substrate temperature, distance from printhead to substrate, and the type of substrate surface. An analytical model is developed to evaluate the interaction of oscillation and viscous damping in the droplet during impact. The third problem covered in the thesis is the deposition of multiple ink droplets on the drum surface. Interaction between droplets causes drawback effect, which degrades print quality. We define a parameter to quantify the drawback effect with varied deposition conditions. A simple model is provided to predict conditions for making continuous lines based on the results of two ink droplets deposition. To understand the hydrodynamics in causing drawback effect, a series of experiments using large liquid droplets are carried out. Focus is put on the evolution of spread length and dynamics of contact line. Correlations for maximum and minimum spread lengths are developed, which are used to reveal the cause of drawback effect in the deposition of ink droplets.

Introduced in 1991, solid ink color printing technology is widely used in the office printing, prepress proofing, and wide format color printing markets. Ink droplets are first deposited on a rotating drum and then transferred to paper to reproduce images with high print quality. The objective of this thesis is to develop scientific knowledge of ink droplet deposition, which is needed for precise image buildup on the drum surface. The first problem studied in the thesis is droplet formation from the printhead with varied working voltages and jetting frequencies. Attention is paid to the formation of satellite droplets, the contraction of ligaments and the startup of high frequency jetting. The jetting conditions for obtaining consistent droplet generation with satellites are determined. A theoretical model is developed to predict the lifetime of ligaments. The second problem we studied is the deposition of single droplets on solid surfaces. The surface texture and final shape of deposited droplets are correlated with impact conditions, which include printhead temperature, substrate temperature, distance from printhead to substrate, and the type of substrate surface. An analytical model is developed to evaluate the interaction of oscillation and viscous damping in the droplet during impact. The third problem covered in the thesis is the deposition of multiple ink droplets on the drum surface. Interaction between droplets causes drawback effect, which degrades print quality. We define a parameter to quantify the drawback effect with varied deposition conditions. A simple model is provided to predict conditions for making continuous lines based on the results of two ink droplets deposition. To understand the hydrodynamics in causing drawback effect, a series of experiments using large liquid droplets are carried out. Focus is put on the evolution of spread length and dynamics of contact line. Correlations for maximum and minimum spread lengths are developed, which are used to reveal the cause of drawback effect in the deposition of ink droplets.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The efficiency of a fungicide is the result of the combination of a variety of factors including: time of application, environmental conditions, physiological condition of plant and application technology used. Already to the latter the proper the deposition and distribution of the active ingredient in the target is decisive for efficiency. The objective of this study was to evaluate the optimal droplet spectrum depending on the characteristics of plant architecture of soybean varieties. Two trails were conducted in the experimental area Phytus Institute in the city of Itaara, central region of Rio Grande do Sul in 2009/2010. The trial consisted of comparison of eight cultivars with different architectural characteristics of the plant with fungicide application using fine droplet spectrum. In Experiment 2, four cultivars were tested with application of fungicide using four spectra drops (very fine, fine, medium and coarse). To evaluate the effect of the treatments were assessed the following parameters: number of drops.cm-2, volume median diameter, Leaf Area Index, plant height, number of branches.plant-1, AUCPD, percentage of incident light in the canopy, yield soybean and yield components. The data of trial 1 showed that the architecture of plants (plant height, number of branches.plant-1 and LAI) significantly affected the deposition of droplets in the bottom and middle of the cultivars. It can also be inferred that the soybean cultivars are grouped due to their architectural characteristics allowing coverage similar drops. In trial 2, the application of fungicides with different droplet spectra allowed significant variations in disease control and on soybean yield. The fine droplet spectrum was more control and consistency in droplet deposition between the four cultivars. / A eficiência de um fungicida é o resultado da associação de uma série de fatores como: momento da aplicação, condições ambientais, condição fisiológica da planta e tecnologia de aplicação utilizada. Já para esta última a adequada deposição e distribuição do ingrediente ativo no alvo é determinante para eficiência do processo. O objetivo deste trabalho foi determinar o espectro de gotas ideal em função das características de arquitetura de planta de cultivares de soja. Foram conduzidos dois experimentos na área experimental do Instituto Phytus, no município de Itaara, região central do Rio Grande do Sul na safra 2009/2010. O experimento 1 consistiu do comparativo de oito cultivares com características variadas de arquitetura de planta com aplicação de fungicida utilizando espectro de gotas fino. No Experimento 2, foram testadas quatro cultivares com aplicação de fungicida utilizando quatro espectros de gotas (muito fino, fino, médio e grosso). Para avaliar o efeito dos tratamentos foram determinados os seguintes parâmetros: número de gotas.cm-2, diâmentro mediano volumétrico, Índice de Área Foliar, estatura de plantas, número de ramos.planta-1, AACPFa, percentual de luz incidente no dossel produtividade da soja e componentes do rendimento. Os dados do experimento 1 indicaram que a arquitetura de plantas (estatura de plantas, número de ramos.planta-1 e IAF) influenciou significativamente a deposição de gotas no terço inferior e médio das cultivares. Também pode-se inferir que as cultivares de soja se agrupam em função de suas características de arquitetura permitindo cobertura de gotas semelhante. No experimento 2 a aplicação de fungicida com diferentes espectros de gotas possibilitaram variações significativas no controle da doença bem como na produtividade da soja. O espectro de gotas fino teve maior consistência no controle e deposição de gotas entre as quatro cultivares.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The suitability of application technology, particularly with regard to spray nozzles and spray rates to the target characteristics, mainly related to plant architecture, can improve the quality of the deposition of fungicides, which in turn can maximize efficiency of asian rust control and soybean yield. This study aimed to evaluate the control of the asian rust and yield of soybean due to the application of fungicides with different spray nozzles and spray rates on cultivars with different plant architectures. For this purpose an experiment was conducted in Itaara - RS, in a randomized block design with split plots and two of the factors arranged in bands. The first factor (cultivars) were arranged in bands on the main plots. The second factor (nozzles) was placed in bands in the subplots and the third factor (spray rates) were randomized within subsubplots. Were used four replications (blocks). Were used soybean cultivars A 6411 RG, BMX Apollo RR, TMG 4001 RR, A 7636 RG and BMX Potência RR. As a second factor, were used the spray nozzles XR11001, TJ-6011002 and TXA800067 and as the third factor application rates 70, 100 and 130 L.ha-1, plus a control without application. There were two applications of fungicides. The parameters evaluated were leaf area index (LAI) stratified by thirds of the canopy, the percentage of luminance within the lower and middle thirds of the canopy, the percentage of canopy closure, the number of branches.m-2, height plant, the shape of leaves, the relative chlorophyll content in the three thirds of the canopy, the density, DMV, homogeneity and relative amplitude of the drops, the severity of the asian rust and yield and thousand grain weight stratified in three thirds canopy. The results indicate the need for parameters spray nozzles and spray rates are adjusted to the plant architecture of the cultivars, especially the leaf area index (LAI) and plant height. / A adequação da tecnologia de aplicação, principalmente no que se refere a pontas de pulverização e taxas de aplicação,às características do alvo, relacionadas principalmente a arquitetura de plantas, pode melhorar a qualidade da deposição dos fungicidas, que por sua vez pode maximizar da eficácia de controle da ferrugem asiática e a produtividade da soja.O presente trabalho objetivou avaliar o controle da ferrugem asiática e a produtividade da cultura da soja em função da aplicação de fungicidascom diferentes pontas de pulverização etaxas de aplicação em cultivares com diferentes arquiteturas de planta. Para isso foi conduzido um experimento em Itaara RS, no delineamento blocos ao acaso com parcelas subsubdivididas e com dois dos fatores dispostos em faixas. O primeiro fator (cultivares) foi disposto em faixas sobre as parcelas principais. O segundo fator (pontas) foi disposto em faixas nas subparcelas e o terceiro fator (taxas de aplicação) foi casualizado dentro das subsubparcelas. Foram utilizadas quatro repetições (blocos). Foram utilizadas as cultivares de soja A 6411 RG, BMX Apolo RR, TMG 4001 RR, A 7636 RG e BMX Potência RR. Como segundo fator, foram utilizadas as pontas de pulverização XR11001, TJ-6011002 e TXA800067 e, como terceiro fator as taxas de aplicação 70, 100 e 130 L.ha-1, mais um tratamento testemunha sem aplicação. Foram realizadas duas aplicações de fungicidas. Os parâmetros avaliados foram o índice de área foliar (IAF) estratificado por terços do dossel, o percentual de iluminância no interior dos terços inferior e médio do dossel, o percentual de fechamento do dossel, o número de ramos.m-2, a estatura das plantas, o formato das folhas, o teor relativo de clorofila nos três terços do dossel, densidade, DMV, homogeneidade e amplitude relativa das gotas nos três terços do dossel, a severidade da ferrugem asiática, a produtividade e a massa de mil grãos estratificada nos terços do dossel. Os resultados obtidos indicam a necessidade de os parâmetros de aplicação pontas de pulverização e taxas de aplicação serem ajustados em função da arquitetura das cultivares, principalmente ao índice de área foliar (IAF) e estatura de plantas.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nowadays there is a trend of become the operational of agrochemicals spray faster. Then, it may cause a direct impact on the spray quality of a given product, influencing even directly the effectiveness of it control. The present study investigated the feature of application as reduced spray rates in combination with different spray nozzles in two wheat cultivars. Field experiment was conducted in the winter of 2011 at Institute Phytus experimental field, on Itaara, central region of Rio Grande do Sul. It was test rates of 180, 140, 100 and 60 L/ha applied with the nozzles XR 11001, TT 11001 and TT 110015 on Fundacep 52 and Quartzo wheat cultivars, on three times: during the stem elongation, in head emission and in full flowering. For collection of drops of dye was used application on Contact paper cards, which were placed in exactly the same position and with the same format that the leaves if desired look. In each application was performed to characterize the quality as this: volume median diameter (VMD), SPAN (RA), number of droplets per square centimeters and percentage of coverage. Common to both cultivars, the DMV was conditioned only by the nozzles, being always smaller for XR 11001, and AR did not vary in any situation. The interaction between spray rates and spray nozzles was more decisive in droplet deposition on the cultivar Fundacep 52 than cultivar Quartzo, and on number of droplet per square centimeters than percentage of coverage. The nozzle XR 11001 tended to result in the greatest number of droplets per square centimeter, while the TT 11001 tended to generate the highest percentage of coverage. Reductions in spray rate normally produce more regular decreases in deposits when were used the TT nozzles regarding XR nozzle. / Em um cenário onde o aumento do ritmo operacional da aplicação de agroquímicos é uma das prioridades, podendo atrelar impactos diretos na qualidade da aplicação de determinado produto, influenciando, inclusive, diretamente a eficácia de controle deste, o presente trabalho objetivou estudar as características da aplicação conforme redução das taxas de aplicação em associação com diferentes pontas de pulverização em duas cultivares de trigo. Foi conduzido experimento de campo no inverno de 2011 em área experimental do Instituto Phytus, município de Itaara, região central do Rio Grande do Sul, testando as taxas de 180, 140, 100 e 60 L/ha aplicadas com as pontas XR 11001, TT 11001 e TT 110015 sobre as cultivares Fundacep 52 e Quartzo em três momentos. Para coleta das gotas foi utilizada aplicação de corante sobre cartões de papel Contact, os quais foram alocados exatamente na mesma posição e com mesmo formato das folhas que se desejou analisar. Em cada aplicação foram avaliados: área foliar, diâmetro mediano volumétrico (DMV), amplitude relativa (AR), número de gotas/cm2 e percentual de cobertura. O DMV foi condicionado apenas pelas pontas, sendo sempre menor para XR 11001, e a AR não apresentou variação em nenhuma situação. A interação entre taxas de aplicação e pontas de pulverização foi mais determinante na deposição de gotas sobre a cultivar Fundacep 52, em relação a cultivar Quartzo, e sobre número de gotas/cm2, comparativamente ao percentual de cobertura. A ponta XR 11001 tendeu a originar os maiores número de gotas/cm2, enquanto que a ponta XR 11001 tendeu a gerar os maiores percentuais de cobertura. Reduções na taxa de aplicação tenderam a gerar decréscimos mais regulares nos depósitos provenientes das pontas TT do que da ponta XR.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Leaf rust and leaf spots caused by Bipolaris sorokiniana and Drechslera tritici-repentis, are diseases that dramatically reduce the productivity of wheat. Depending on the difficulty in having cultivars resistant to all diseases, chemical control is an alternative, technically and economically viable. To maximize the residual of fungicides is necessary to optimize the factors related with spray minimizing the losses due to disease incidence. The goal of the work was to determine the influence of the number of drops in the penetration of fungicides and its control efficacy at various stages of application. The experimental design used was randomized block in Split plot design, totaling 20 treatments and four replications. The treatments were two wheat cultivars (Fundacep Cristallino and Fundacep Nova Era); three spray tips (XR 11002, TJ 60-11002 and TX 8002); 3 fungicides: Pyraclostrobin + Epoxiconazol; Epoxiconazol and Pyraclostrobin, and a control without any application. It was evaluated the density of drops per square centimeter, DMV, DMN, severity of disease, weight of hectoliter and productivity of the crop. The use of fungicides pyraclostrobin and epoxiconazol + piraclostrobia, respectively, provided the better control of diseases, higher productivity and greater weight of hectoliter in Nova Era cultivar. On the other hand, Cristalino cultivar with lower impact of the diseases did not show difference on efficacy of the fungicides used. The control of diseases was influenced by the DMV/DMN ratio due to the use of different spray tips. Tips with thin/medium drop spectrum performed better coverage at the lower part of the canopy, providing fewer establishments of the diseases. The correlation between the variables showed that the second application of fungicides was the one that crashed in the calculation of the area under the curve of progress of diseases (AACPD), hectoliter weight and yield. The greater disease pressure at flowering can explain this result. / A Ferrugem da folha e as manchas foliares causadas por Bipolaris sorokiniana e Drechslera tritici-repentis, são doenças capazes de reduzir drasticamente a produtividade da cultura do trigo. Em função da dificuldade em dispor de cultivares resistentes a todas as doenças, o controle químico é uma alternativa viável, técnica e economicamente. Para maximizar o residual dos fungicidas é necessário otimizar os fatores relacionados à tecnologia de aplicação minimizando os danos em função da incidência das doenças. O objetivo do trabalho foi determinar a influência do número de gotas na penetração dos fungicidas e na sua eficácia de controle em diferentes momentos de aplicação. O delineamento experimental utilizado foi de Blocos ao acaso em parcelas subsubdivididas, totalizando 20 tratamentos em quatro repetições. Os tratamentos foram constituídos por duas cultivares de trigo (Fundacep Cristalino e Fundacep Nova Era); três pontas de pulverização (XR 11002, TJ 60-11002 e TX 8002); 3 fungicidas: Piraclostrobina + Epoxiconazol; Epoxiconazol e Piraclostrobina, mais uma testemunha sem aplicação. Foi avaliada a densidade de gotas por centímetro quadrado, diâmetro mediano volumétrico (DMV), diâmetro mediano numérico (DMN), severidade das doenças, peso do hectolitro e produtividade da cultura. A utilização dos fungicidas epoxiconazol+ piraclostrobina e piraclostrobina, respectivamente, proporcionaram o melhor controle de doenças, melhor produtividade e maior peso do hectolitro na cultivar Nova Era. Por outro lado, na cultivar Cristalino submetida a um menor impacto das doenças, não houve diferença com relação aos fungicidas utilizados. O controle de doenças foi influenciado pelo espectro de gotas proporcionado devido a utilização das diferentes pontas de pulverização. Pontas com espectro fino/médio apresentaram melhor cobertura do terço inferior do dossel, proporcionando menor estabelecimento das doenças. A correlação entre as variáveis mostrou que a segunda aplicação dos fungicidas foi a que mais impactou no calculo da área abaixo da curva de progresso das doenças (AACPD), produtividade de grão e peso do hectolitro. Esse resultado pode ser explicado pela maior pressão de doença no estádio de florescimento.

Dans la production d'électricité, un des leviers centraux pour réduire les détériorations et les pertes causées par l'humidité dans les turbines à vapeur est l'étude des films liquides. Ces films minces, sont créés par la déposition de gouttes et sont fortement cisaillés. Des gouttes peuvent ensuite être arrachées du film. A l'heure actuelle, aucun modèle complet et valide n'existe pour décrire ce phénomène. Un modèle 2D à formulation intégrale associé à des lois de fermetures a été dérivé pour représenter ce film. Comparé aux équations classiques de Saint-Venant, le modèle prend en compte davantage d'effets : le transfert de masse, l'impact des gouttes, le cisaillement à la surface libre, la tension de surface, le gradient de pression et la rotation. Une analyse des propriétés du modèle (hyperbolicité, entropie, conservativité, analyse de stabilité linéaire, invariance par translation et par rotation) est réalisée pour juger de la pertinence du modèle. Un nouveau code 2D est implémenté dans un module de développement libre du code EDF Code Saturne et une méthode de volumes finis pour un maillage non-structure a été développée. La vérification du code est ensuite effectuée avec des solutions analytiques dont un problème de Riemann. Le modèle, qui dégénère en modèle classique de Saint-Venant pour le cas d'un film tombant sur un plan inclinée, est validé par l'expérience de Liu and Gollub, 1994, PoF et comparé à des modèles de références (Ruyer-Quil and Manneville, 2000, EPJ-B et Lavalle, 2014, PhD thesis). Un autre cas d'étude met en scène un film cisaillé en condition basse-pression de turbine à vapeur et, est validé par l'expérience de Hammitt et al., 1981, I. Enfin, le code film est couplé aux données 3D du champ de vapeur autour d'un stator d'une turbine basse-pression du parc EDF, issues de Blondel, 2014, PhD thesis. Cette application industrielle montre la faisabilité d'une simulation d'un film en condition réelle du turbine à vapeur. / In the electricity production, one central key to reduce damages and losses due to wetness in steam turbines is the study of liquid films. These thin films are created by the deposition of droplets and are highly sheared. This film may then be atomized into coarse water. At the moment, no comprehensive and validated model exists to describe this phenomenon. A 2D model based on a integral formulation associated with closure laws is developed to represent this film. Compared to classical Shallow-Water equation, the model takes into account additional effect : mass transfer, droplet impact, shearing at the free surface, surface tension, pressure gradient and the rotation. The model properties (hyperbolicity, entropy, conservativity, linear stability, Galilean invariance and rotational invariance) has been analyzed to judge the pertinence of the model. A new 2D code is implemented in a free module of the code EDF Code Saturne and a finite volume method for unstructured mesh has been developed. The verification of the code is then carried out with analytical solutions including a Riemann problem. The model, which degenerates into classical Shallow-Water equations for the case of a falling liquid film on a inclined plane, is validated by the experiment of Liu and Gollub, 1994, PoF and compared to reference models (Ruyer-Quil and Manneville, 2000, EPJ-B et Lavalle, 2014, PhD thesis). Another study depicts a sheared film under low-pressure steam turbine conditions and is validated by the experiment of Hammitt et al., 1981, FiI. Lastly, the code film is coupled to 3D steam data around a fixed blade of a BP100 turbine, from Blondel, 2014, PhD thesis. This industrial application shows the feasibility of liquid film's simulation in real steam turbine condition.