Dans le cadre de la pulvérisation agricole, la diminution de la quantité des intrants est devenue une étape cruciale, et ce notamment en viticulture. La pulvérisation de précision en viticulture implique cependant une maitrise conjointe du matériel utilisé, des produits et de la répartition de ces produits sur le feuillage. Dans ce contexte, nombreuses sont les recherches menées sur l’optimisation d’utilisation des produits phytosanitaires, leur objectif final étant de réduire de manière significative la quantité d’intrants dans la culture. Cependant, peu de travaux ont été effectués sur l’étude du comportement des produits directement sur le feuillage, ce qui constitue donc l’objectif de cette thèse. La première partie de ce travail est consacrée particulièrement à l’analyse de l’état de la surface foliaire, en se focalisant spécifiquement sur l’étude de la rugosité de surface de la feuille qui constitue un paramètre essentiel dans le processus d’adhésion du produit pulvérisé sur la feuille. L’analyse de la surface de la feuille est réalisée en déterminant les caractéristiques texturales extraites d’images microscopiques. Un nouvel indicateur de rugosité est proposé ainsi que, des paramètres spatiaux et fréquentiels sont utilisés pour estimer et la rugosité de la feuille. Ces paramètres permettent ensuite la caractérisation de l’homogénéité de la surface et la détection des nervures/poils au niveau de la surface de la feuille. Cette partie représente une base fondamentale pour mieux comprendre le comportement des gouttelettes pulvérisées sur la feuille de vigne. La deuxième partie de ce travail de thèse est consacrée à des études expérimentales, qui ont pour but de définir et construire des modèles statistiques permettant d’estimer la quantité de produit restant sur la feuille ou la surface occupée par les gouttes. Ces modèles prennent en considération différents paramètres de pulvérisation, tels que la taille de la goutte et sa vitesse, la tension superficielle du produit, l’angle d’inclinaison et la rugosité de la surface de la feuille. Ces modèlespourraient être vus comme des outils de décision communs pour optimiser la quantité du produit pulvérisé et l’estimation du produit restant sur la feuille, et comme un outil d’aide pour optimiser les bancs d’essais et de tests de la qualité de la pulvérisation. / In the context of agricultural spraying, reducing the amount of input became a crucial step particularly in viticulture. The development of spraying precision in this domain needs the mastery of the use of spray equipment, product and distribution of these products on the foliage. In this area, many research have been done, their main goal being to optimize the use of plant product protection and to reduce significantly the input quantity inside the culture. However, few research has been done on the behavior of the product directly on the foliage which constitutes finally the main goal of this thesis. The first part of this report deals particularly with the analysis of leaf surface state by focusing precisely on the leaf surface roughness, one of the main parameters in product adhesion process. A leaf surface analysis is performed by determining the textural features extracted from microscopic images. A new roughness indicator is proposed and, spatial and frequency parameters were used to estimate and characterize the leaf roughness. These parameters allow both the characterization of surface homogeneity and the detection of the presence of rib/hair on the leaf surface. Indeed, this part represents a fundamental basis for understanding the spray droplet behavior on the vine leaf. The second part of this thesis deals with experimental studies which aim to define and to create statistical models to estimate the amount of product remaining on the leaf surface or the surface occupied by droplets. These models consider different spray parameters, such as droplet size and velocity, surface tension of the product, slope angle and roughness of the leaf. These models could be seen as aid-decision tools to optimize the amount of spray and the estimated product remaining on the leaf.

This thesis is an investigation of surface morphology and electronic structure of self-assembled monolayers (SAMs) and solid water films deposited on these SAMs using metastable impact electron spectroscopy (MIES) and infrared reflection-absorption spectroscopy (IRRAS). MIES uses electronically excited slow helium atoms which interact exclusively with the outermost surface layer. The results suggested that in the SAMs containing an odd number of carbon atoms the molecular orbitals localized on the terminal methyl groups are more exposed at the surface compared to those with an even number of carbon atoms. It was also established that solid water films are more uniform on a SAM substrate containing an odd number of carbon atoms. Thermal transformation of amorphous solid water to polycrystalline ice was also observed. MIES suggested that the molecular orbital of water attributed to the lone pair on the oxygen atom became less accessible at the surface upon the transformation.

The discovery and subsequent synthesis of metal containing fullerenes- IFS (Inorganic Fullerene-like Structures) by R. Tenne et al. has generated considerable scientific interest with great potential impact in many industrial application areas such as lubrication. The lubrication mechanism (tribofilm formation) via exfoliation and deposition of the atomic layers from this cage-like IF-particles was revealed and demonstrated first by this research group. The incorporation of the nanoparticles into lubricants (oils, greases) is however not straightforward. When two surfaces are sliding against each other and a lubricant is used, a thin layer (tribofilm) is formed on the contact area. The friction reducing effects of the nanoparticles can be altered or hindered by certain additives that are used in lubricative oils. The effects of such additives on the tribological behavior of the nanoparticles are investigated by analyzing the tribofilms formed on the worn surfaces using energy-dispersive X-ray spectroscopy in a scanning electron microscope. Another challenge of nanoparticles in lubricants is the penetration of the nanoparticles into the contact zone. A possible solution of this problem is briefly discussed. A modified burnishing technique can be used to coat sliding metallic surfaces with a friction reducing tribofilm. The morphology and composition of these tribofilms was investigated with analytical electron microscopy techniques. In the second part of the thesis electron microscopy was used to investigate the material transfer. Titanium is an elements with high adhesive ability to the counter surface, it displays poor tribological properties in sliding metallic contacts. This can lead to material transfer and consequently severe surface damage. The cold formation and machining of titanium, thus can lead rapid tool wear and poor surface finish. Electron microscopy techniques were used to study the mechanism of titanium transfer to different counter surfaces.

No description available.

Orientador: Rubens Maciel Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T18:46:56Z (GMT). No. of bitstreams: 1 Oliveira_PatriciaCandiotoMigliari_D.pdf: 1584587 bytes, checksum: 8622cb86aacfe987908422e98c40d2c8 (MD5) Previous issue date: 2007 / Resumo: O trabalho envolveu modelo estruturado adaptado de um modelo estruturado de crescimento para processo de fermentação contínua realizado em um bioreator do tipo torre com células imobilizadas para produção de etanol. O modelo estruturado utilizado inclui equações de balanço para as rotas metabólicas fermentativa e respiratória, assim como termos cinéticos para o efeito de inibição pelo etanol, substrato e saturação celular no pellet. Os parâmetros cinético do modelo estruturado foram otimizados através da metodologia desenvolvida por Rivera (2005) onde envolve a aplicação de Algoritmo Genético, Planejamento Fatorial Fracionário proposto por Plackett Burman (1946) e Algoritmo Quasy Newton. Os resultados obtidos na simulação do modelo utilizando os parâmetros otimizados por esta metodologia representou de forma efetiva o modelo. A otimização do processo teve inicio com a Análise de Superfície de Resposta, que consistiu em um planejamento fatorial em estrela de dois níveis (-1 e +1) com um ponto central. A metodologia por Superfície de Resposta mostrou-se uma ferramenta poderosa para otimização preliminar das variáveis operacionais no sentido de que seus resultados foram usados como estimativas iniciais para o procedimento formal de otimização, SQP (Programação Quadrática Sucessiva). Esta metodologia de Superfície de resposta possibilita visualização do comportamento das variáveis que se quer otimizar, identificando a região do ponto ótimo, o que não é possível pelo método SQP. A metodologia SQP foi implementada com sucesso no modelo determinístico, obtendo as melhores condições de operação para as variáveis manipuláveis / Abstract: The work involved adapted of a structured model of growth structured model for process of continuous fermentation accomplished in a bioreator of the type tower with immobilized cells for etanol production. The used structured model includes reaction rate equations for the respiratory and glicolitic metabolic pathways, as well as kinetic terms for the inhibition effect for the etanol, substrate and cellular saturation in the pellet. The kinetic of the structured model parameters went optimized through to methodology developed by Rivera (2005) where it involves the application of Genetic Algorithm, methodology of Plackett¿Burman (1946) and Algorithm Quasi Newton. The results obtained in the simulation of the model using the parameters optimized for this methodology represented in an effective way the model. The optimization of the process had I begin with the Analysis of Surface of Answer, that consisted of a planning fatorial in star of two levels (-1 and +1) with a central point. The methodology for Surface of Answer a powerful tool was shown for preliminary optimization of the operational variables in the sense that its results were used as initial estimates for the formal procedure of optimization, SQP. This methodology of answer Surface facilitates visualization of the behavior of the variables that if that otimizar, identifying the area of the great point, what is not possible for the method SQP. The methodology SQP was implemented with success in the model deterministic, obtaining the best operation conditions for the variables manipulated. / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

This dissertation is concerned with three-dimensional (3D) sensing and 3D scan representation. Three-dimensional records are important tools in several disciplines; such as medical imaging, archaeology, and mobile robotics. This dissertation proposes the normal-distributions transform, NDT, as a general 3D surface representation with applications in scan registration, localisation, loop detection, and surface-structure analysis. After applying NDT, the surface is represented by a smooth function with analytic derivatives. This representation has several attractive properties. The smooth function representation makes it possible to use standard numerical optimisation methods, such as Newton’s method, for 3D registration. This dissertation extends the original two-dimensional NDT registration algorithm of Biber and Straßer to 3D and introduces a number of improvements. The 3D-NDT scan-registration algorithm is compared to current de facto standard registration algorithms. 3D-NDT scan registration with the proposed extensions is shown to be more robust, more accurate, and faster than the popular ICP algorithm. An additional benefit is that 3D-NDT registration provides a confidence measure of the result with little additional effort. Furthermore, a kernel-based extension to 3D-NDT for registering coloured data is proposed. Approaches based on local visual features typically use only a small fraction of the available 3D points for registration. In contrast, Colour-NDT uses all of the available 3D data. The dissertation proposes to use a combination of local visual features and Colour-NDT for robust registration of coloured 3D scans. Also building on NDT, a novel approach using 3D laser scans to perform appearance-based loop detection for mobile robots is proposed. Loop detection is an importantproblem in the SLAM (simultaneous localisation and mapping) domain. The proposed approach uses only the appearance of 3D point clouds to detect loops and requires nopose information. It exploits the NDT surface representation to create histograms based on local surface orientation and smoothness. The surface-shape histograms compress the input data by two to three orders of magnitude. Because of the high compression rate, the histograms can be matched efficiently to compare the appearance of two scans. Rotation invariance is achieved by aligning scans with respect to dominant surface orientations. In order to automatically determine the threshold that separates scans at loop closures from nonoverlapping ones, the proposed approach uses expectation maximisation to fit a Gamma mixture model to the output similarity measures. In order to enable more high-level tasks, it is desirable to extract semantic information from 3D models. One important task where such 3D surface analysis is useful is boulder detection for mining vehicles. This dissertation presents a method, also inspired by NDT, that provides clues as to where the pile is, where the bucket should be placed for loading, and where there are obstacles. The points of 3D point clouds are classified based on the surrounding surface roughness and orientation. Other potential applications include extraction of drivable paths over uneven surfaces.

Secondary Ion Mass Spectrometry (SIMS) is a powerful technique for high spatial resolution chemical mapping and characterization of native surfaces. The use of massive cluster projectiles has been shown to extend the applicable mass range of SIMS and improve secondary ion yields 100 fold or beyond. These large projectiles however, present a challenge in terms of focusing due to the initial spatial and kinetic energy spreads inherent to their generation. In the present work, we describe the development and construction of a novel primary ion (PI) column employing a gold nanoparticle – liquid metal ion source (AuNP-LMIS) and the coupling to ultrahigh resolution mass spectrometers (e.g., Fourier Transform Ion Cyclotron Resonance Mass Spectrometer, FT-ICR MS) for accurate chemical characterization of complex biological surfaces. This work describes the ion dynamics, development and the experimental characterization of the AuNP-LMIS.

This diploma thesis deals with the final quality of the surface under variable working conditions during milling. The first part deals with the definition of qualitative parameters describing surface properties. This is followed by a brief description of the cutting resistance measurements. The thesis is complemented by experimental verification using front milling and its evaluation. The aim of the experiment is to determine the dependence of the surface quality and the size of cutting resistors under the variable working conditions of the machine that do not make a common part of the manufacturing processes.

La synthèse de catalyseurs sans métaux nobles est une voie prometteuse pour rendre accessible à l’échelle mondiale les piles à combustible. L’analyse électrochimique de ces matériaux n’est pas aisée que ce soit pour comparer les propriétés électro catalytiques ou pour comprendre le fonctionnement de ces catalyseurs. Ceci provient du fait que la communauté scientifique évalue les performances catalytiques à l’échelle du matériau, donc sur un très grand nombre d’objets dont la réponse est moyennée. Les travaux présentés dans ce mémoire ont mis en place une méthode d’analyse de l’activité électrocatalytique de matériaux sans métaux nobles pour la réduction de l’oxygène en milieu acide par microscopie électrochimique à balayage. Cette approche permet d’étudier aussi bien macroscopiquement que microscopiquement les catalyseurs et d’étudier simultanément plusieurs catalyseurs, ce qui rend plus fiable la comparaison des résultats. Le dispositif présenté dans ce travail a permis de comparer différents catalyseurs avec des compositions proches ainsi que d’étudier l’influence de différentes paramètres sur un catalyseur : le chargement, la surface, la masse déposée et la quantité de Nafion ajoutée. Il a aussi été montré qu’il était possible d’étudier la stabilité des catalyseurs via ce dispositif. Ces différents résultats suggèrent que la méthode mise en place est polyvalente et permettra de nombreuses autres études. / The decrease of fuel cells cost is necessary to provide a worldwide access to the technology. Synthesis of noble metal-free catalysts is a promising way to achieve this goal. The electrochemical analysis of these materials is however not easy either to compare the electrocatalytic properties or to understand the performances of these catalysts. The scientific community generally studies catalysts at a macroscale, where the recorded response is averaged on a very large number of catalytic objects. The works presented here shows the setup of a method to analyze the electrocatalytic activity of noble metal-free catalyst for the oxygen reduction reaction in acidic media by scanning electrochemical microscopy. This method brings several advantages such as the possibility to study and compare multiple catalysts on the same sample at a macro- or a microscale. The comparison of several catalysts with this setup is then. A catalyst has been studied under various conditions of: loading, surface area, weight of catalyst and quantity of additives such as Nafion. The investigation of the material stability is also illustrated. These results suggest large range of application of the technique and many possibilities in the future are now open to investigated noble metal-free electrocatalytic materials.

Ce travail s’intéresse à la modélisation de la variabilité des surfaces frottantesde garnitures de freins automobile et a pour objectif principal d’améliorer lesmodèles éléments finis de prédiction d’instabilités dynamiques conduisant au crissement. La variabilité est étudiée au sens de la description et de l’évolution des surfaces en contact. Une analyse statistique expérimentale de plusieurs plaquettes, soumises à quatre programmes d’usure différents, permet de construire une description non déterministe des surfaces en contact. Cette description fait intervenir soit des champs aléatoires pour la représentation de la topographie des surfaces, soit des paramètres aléatoires dans les lois de contact, pour tenir compte de la variabilité au niveau structurel et tribologique. Un modèle de frottementlocal intégrant la dépendance à la pression, la température et la vitesse de glissement est proposé. Une première simulation montre que la modélisation permet d’obtenir des distributions de pression réalistes. La méthodologie proposée est ensuite évaluée sur deux systèmes de freinage industriels présentant des comportements au crissement différents. Les résultats de campagnes d’essais vibratoires et acoustiques préalables, par vibrométrie Laser et holographie acoustique, permettent de vérifier et d’ajuster la qualité des modèles éléments finis de ces systèmes. L’impact de la variabilité des surfaces sur le crissement est observé sur banc d’essais puis simulé par l’analyse fréquentielle. Les comparaisons confirment que la méthodologie permet de vérifier l’impact de l’évolution de l’interface plaquette-disque sur le comportement crissant de systèmes de freinage complexes. / This work concerns the modelling of the variability of automotive brake liningsurfaces, and has for main purpose the improvement of the predictive aspect of finite element model dealing with the study of dynamic instabilities leading to squeal. The study of the variability is done considering the description and the evolution of the surfaces in contact. An experimental statistical analysis of several brake pads, following four different wear programs, allows the development of a non-deterministic description of the surfaces in contact. This description brings into play either random fields for the modelling of the surfaces topography modelling, or random parameters for the modelling of contact laws, lining structure and tribological behaviour. A local rubbing model considering pressure, temperature and slipping velocity is suggested. Moreover, realistic pressure distributions are achieved. Afterwards, the method given is assessed for two different industrial braking systems, with two different squeal behaviours. The results of a preliminary vibratory and acoustic series of tests, by means of Laser vibrometry and acoustic holography, allow to check and to adjust the quality of the finite element models. The consequences of the surfaces variability on the squeal is examined on test benches, and then simulated with the frequency analysis method. Comparisons with experimental results confirm the capacity of the methodology to analysis the impact of the pad-to-disc interface evolutions on the squealing behaviour of complex brake systems. The methodology capacity for checking the impact of the pad-disc interface evolution on the squeal behaviour of complex braking systems is confirmed by comparisons.