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Dissertations / Theses on the topic 'Concept of surface'

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Published: 9 March 2023
Last updated: 10 March 2023

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1

Cox, Patrick, Christie Jordan, Kate Mangum, John Mitchell, Kevin O'Neill, and Kevin Seraile. "Unmanned surface combatant considerations for concept exploration." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/6962.

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This capstone project explored the operational and design considerations/constraints for an autonomous Unmanned Surface Combatant (USC). Using a USC in selected missions could lead to cost reductions and enhanced capabilities when compared with similar manned combatants by eliminating personnel and automating ship operations. Operations and Support (O&S) costs, which include personnel costs, are a large portion of the Navy's total ownership costs (TOC) for surface combatants, and can be as high as 38 percent of the TOC. Enhanced capabilities for a USC could be derived from performing operational activities manned ships cannot
and automated tasks could be performed more efficiently and effectively by a computer system than a human. A modified waterfall systems engineering process model was used to explore a USC concept. A needs analysis was performed, and mine warfare and anti-submarine warfare were identified as appropriate military missions for an initial USC concept. Top level constraints for a USC concept and support missions were developed. Design considerations, relevant technologies, and concept risks were investigated. This capstone project concluded that a lower cost, higher capability autonomous USC is possible based on the current state of relevant technologies. However there are significant technical challenges to overcome before full autonomy is possible. Further, more rigorous design studies are recommended.
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2

Goggins, David A. "Response surface methods applied to submarine concept exploration." Thesis, Springfield, Va. : Available from National Technical Information Service, 2001. http://handle.dtic.mil/100.2/ADA393310.

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Thesis (M.S. in Naval Architecture and Marine Engineering and M.S. in Mechanical Engineering) Massachusetts Institute of Technology, Sept. 2001.
Includes bibliographical references (leafs 89). Also Available online.
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3

Goggins, David A. (David Alexis) 1966. "Response surface methods applied to submarine concept exploration." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8268.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.
Includes bibliographical references (leaf 89).
It is estimated that 70 to 85 percent of a naval ship's life-cycle cost is determined during the concept exploration phase which places an importance in the methodology used by the designer to select the concept design. But trade-off studies are guided primarily by past experience, rules-of-thumb, and designer preference. This approach is ad hoc, not efficient and may not lead to an optimum concept design. Even worse, once the designer has a "good" concept design, he has no process or methodology to determine whether a better concept design is possible or not. A methodology is required to search the design space for an optimal solution based on the specified preferences from the customer. But the difficultly is the design space, which is non-linear, discontinuous, and bounded by a variety of constraints, goals, and thresholds. Then the design process itself is difficult to optimize because of the coupling among decomposed engineering disciplines and sub-system interactions. These attributes prevent application of mature optimization techniques including Lagrange multipliers, steepest ascent methods, linear programming, non-linear programming, and dynamic programming. To further improve submarine concept exploration, this thesis examines a statistical technique called Response Surface Methods (RSM). The purpose of RSM is to lead to an understanding of the relationship between the input (factors) and output (response) variables, often to further the optimization of the underlying process. The RSM approach allows the designers to find a local optimal and examine how the design factors affect the response in the region around the generated optimal point. RSM can be applied to submarine concept exploration and provide a methodology to: determine the optimal concept design based on customer preference, efficiently perform trade-off studies, determine the feasible design space, and the ability to determine in advance if a specified concept design is feasible and meets all the customer thresholds and constraints.
by David A. Goggins.
S.M.
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4

Schinke, Wolfgang Josef. "A concept for surface reconstruction from digitised data." Thesis, De Montfort University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685931.

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5

Tran, Ich tach. "Vérification de la validité du concept de surface somme par une approche statistique du contact élastique entre deux surfaces rugueuses." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2015. http://www.theses.fr/2015ECAP0010/document.

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Les propriétés de surface, particulièrement microgéométriques, jouent un rôle essentiel dans tous les systèmes tribologiques. L’analyse de la répartition des efforts de contact dans l’interface entre surfaces rugueuses est indispensable à la prédiction du frottement, de l'usure, de l'adhérence, des résistances de contact électrique et thermique… De nombreux modèles ont été proposés ces dernières décennies pour prédire les efforts entre aspérités de surfaces rugueuses. Parmi ces modèles, les modèles statistiques sont majoritairement développés en considérant le contact ente une surface rugueuse équivalente, la surface somme - qui tient compte des microgéométries des deux surfaces en contact ainsi que de leur matériau - et un plan lisse. Cependant la validité de cette modélisation n’a pas été clairement démontrée. L’objectif de notre étude a été de développer un modèle statistique de contact entre deux surfaces rugueuses isotropes aléatoires puis de comparer les résultats obtenus pour ces deux surfaces avec ceux obtenus en considérant la surface somme définie classiquement à partir des deux surfaces rugueuses et un plan lisse. Les différences entre les résultats nous ont amenés à proposer une nouvelle modélisation de la surface somme
Surface properties, particularly micro-geometry, play a key role in all tribological systems. The analysis of the distribution of contact forces in the interface between rough surfaces is essential for the prediction of friction, wear, adhesion, electrical and thermal contact resistance... Many models have been proposed during the last decades to predict the forces between asperities of rough surfaces. Among these models, statistical models are mainly based on the contact between an equivalent rough surface, the sum surface - which combines micro-geometry of the two surfaces in contact and their material - and a smooth plane. However, the validity of this model has not been clearly demonstrated. The aim of our study was to develop a statistical model of the contact between two random isotropic rough surfaces and then compare the results with those obtained by considering the classical sum surface. The differences between the results have led us to propose a new definition for the sum surface
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6

Wood, Nicola Caroline Gwendoline. "Wet on the surface, rethinking the concept of the trailing spouse." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ65062.pdf.

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7

Price, Shelly L. (Shelly Loustaunau) 1974. "Integrating response surface methods and uncertainty analysis into ship concept exploration." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/91361.

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Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.
Includes bibliographical references (p. 60).
by Shelly L. Price.
Nav.E.
S.M.
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8

Franklin, David. "Concept design and market screening of a surface fatigue test rig." Thesis, KTH, Maskinkonstruktion (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185536.

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Swerea KIMAB is one of Europe’s leading institutes for metallic materials and excels in many different areas. KIMAB’s main advantage is its open internal structure where all groups and projects can share information and knowledge between the sections. After moving to new premises it was noted that the surface fatigue test rig that had been used had started to leak oil and was no longer suitable for new projects. Because surface fatigue testing will be of importance in the future for the development of new alloys that will replace existing alloys in for example gears, this thesis was created as a foundation for how a new test rig should be acquired.This thesis goal is to describe KIMAB’s requirements in a test rig and to do a market screening over existing solutions for test rigs. Thereafter a designed concept shall be developed for KIMAB’s specific requirements and describe how it should be made. These different parts will be the ground for how KIMAB should continue in the acquisition of a new rig.The base of the thesis is a literature study in surface fatigue, its mechanics and how these can be affected to give the desired test scenario. This information is used to make a market screening for suitable test rigs that fulfils the requirements. Thereafter a concept generation is made and evaluated during a meeting on KIMAB. The chosen concept will then be designed to be user friendly, robust and as reliable as possible.When the final concept is done and quotes from manufacturers have been gathered for most of the parts in the design, a time and cost estimation was made to give the reader the chance of deciding which alternative is the most suitable for KIMAB. This choice has to be made with regard to future projects and how the market will develop for the ordering of surface fatigue testing.
Swerea KIMAB är ett av Europas ledande institut för metalliska material med spetskompetens inom ett flertal områden. KIMAB’s stora fördel är dess öppna interna struktur där alla grupper och projekt kan dela information och kunskap emellan avdelningarna. Efter att KIMAB flyttade till nya lokaler uppmärksammades det att den kontaktutmattningsrigg de använt under flera år började läcka olja och inte längre var optimal för dagens projekt. Eftersom kontaktutmattning kommer att bli ett viktigare inslag i framtiden då nya legeringar kommer att ersätta befintliga i exempelvis kugghjul, så skapades detta examensjobb som en grund för hur en ny rigg skall införskaffas.Detta examensjobb har som mål att beskriva KIMAB’s behov i en testrigg samt att göra en marknadsundersökning efter befintliga riggar. Därefter skall ett förslag designas på hur en testrigg som är anpassas just för KIMAB’s behov skall kunna byggas. Dessa delar skall sedan ligga som grund för hur KIMAB skall gå vidare i införskaffandet av en ny rigg.Examensarbetets grund ligger i en litteraturstudie i kontaktutmattningsskador samt mekanismerna bakom dessa skador och hur de kan påverkas i ett test scenario. Denna kunskap användes för att undersöka marknaden efter lämpliga riggar som kan uppfylla kraven. Därefter skapades ett antal koncept som utvärderades under ett möte på KIMAB. Det koncept som valdes har därefter designats för att vara så användarvänligt och tillförlitligt som möjligt.När konceptet var färdigställt och prisuppgifter hämtats in på merparten av delarna så har en kostnads och tidskalkyl utförts för att låta läsaren avgöra vilket alternativ som passar bäst för KIMAB. Detta val måste baseras på framtida projekt och hur marknaden ser ut för beställning av kontaktutmattningsprover.
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9

Rangmark, Fredrik. "Concept for an autonomous surface vessel operating in an unknown naval environment." Thesis, KTH, Marina system, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-198517.

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In 2010 about 25% of the Swedish coastal areas had been surveyed with modern bathymetry methods, the rest was surveyed with older methods in the 1800s. By 2015 this portion has increased to 48% and the Swedish Maritime Administration's goal is to have surveyed 75% by 2020. The remaining 25% consists mostly of shallow water with a depth of less than 10 meters. These areas are di-cult to measure with conventional methods; surveying ships equipped with a multi-beam sonar. Of these areas the Swedish Maritime Administration intend to survey 15% by 2022. This is only possible if newer technologies are made available for surveying shallower waters. This thesis is a part of a project developing an autonomous vessel suited for bathymetric surveying in shallow waters. The thesis focuses on the proof of concept as well as the development and testing of a prototype vessel and its systems. The benet of an autonomous vessel like this is that it is supposed to be cheaper and easier to operate than a smaller ship with sonars operated by a crew.
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10

Bucak, Seyda. "The concept of 'driving force' applied to vesicle formation and breakdown in aqueous media." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323215.

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11

Chattot, Raphael, Bacq Oliver Le, Vera Beermann, Stefanie Kühl, Juan Herranz, Sebastian Henning, Laura Kühn, et al. "Surface Distortion as a Unifying Concept and Descriptor in Oxygen Reduction Reaction Electrocatalysis." Nature Publishing Group, 2019. https://tud.qucosa.de/id/qucosa%3A34832.

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Tuning the surface structure at the atomic level is of primary importance to simultaneously meet the electrocatalytic performance and stability criteria required for the development of low-temperature proton-exchange membrane fuel cells (PEMFCs). However, transposing the knowledge acquired on extended, model surfaces to practical nanomaterials remains highly challenging. Here, we propose the ‘Surface Distortion’ as a novel structural descriptor, which is able to reconciliate and unify seemingly opposing notions and contradictory experimental observations in regards to the electrocatalytic oxygen reduction reaction (ORR) reactivity. Beyond its unifying character, we show that surface distortion is pivotal to rationalise the electrocatalytic properties of state-of-art of PtNi/C nanocatalysts with distinct atomic composition, size, shape and degree of surface defectiveness under simulated PEMFC cathode environment. Our study brings fundamental and practical insights into the role of surface defects in electrocatalysis and thus highlights strategies to design more efficient and durable new generation of nanocatalysts
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12

Wieckiewicz, Mieszko, Eric Wolf, Gert Richter, Heike Meissner, and Klaus Boening. "New Concept of Polymethyl Methacrylate (PMMA) and Polyethylene Terephthalate (PET) Surface Coating by Chitosan." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-215855.

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Chitosan is known for its hemostatic and antimicrobial properties and might be useful for temporary coating of removable dentures or intraoral splints to control bleeding after oral surgery or as a supportive treatment in denture stomatitis. This study investigated a new method to adhere chitosan to polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET). There were 70 cylindrical specimens made from PMMA and 70 from PET (13 mm diameter, 6 mm thickness). The materials with ten specimens each were sandblasted at 2.8 or 4.0 bar with aluminum oxide 110 μm or/and aluminum oxide coated with silica. After sandblasting, all specimens were coated with a 2% or 4% acetic chitosan solution with a thickness of 1 mm. Then the specimens were dried for 120 min at 45 °C. The precipitated chitosan was neutralized with 1 mol NaOH. After neutralization, all specimens underwent abrasion tests using the tooth-brushing simulator with soft brushes (load 2N, 2 cycles/s, 32 °C, 3000 and 30,000 cycles). After each run, the specimen surfaces were analyzed for areas of remaining chitosan by digital planimetry under a light microscope. The best chitosan adhesion was found after sandblasting with aluminum oxide coated with silica (U-Test, p < 0.05) in both the PMMA and the PET groups. Hence, with relatively simple technology, a reliable bond of chitosan to PMMA and PET could be achieved.
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13

Wieckiewicz, Mieszko, Eric Wolf, Gert Richter, Heike Meissner, and Klaus Boening. "New Concept of Polymethyl Methacrylate (PMMA) and Polyethylene Terephthalate (PET) Surface Coating by Chitosan." Molecular Diversity Preservation International (MDPI), 2016. https://tud.qucosa.de/id/qucosa%3A30051.

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Chitosan is known for its hemostatic and antimicrobial properties and might be useful for temporary coating of removable dentures or intraoral splints to control bleeding after oral surgery or as a supportive treatment in denture stomatitis. This study investigated a new method to adhere chitosan to polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET). There were 70 cylindrical specimens made from PMMA and 70 from PET (13 mm diameter, 6 mm thickness). The materials with ten specimens each were sandblasted at 2.8 or 4.0 bar with aluminum oxide 110 μm or/and aluminum oxide coated with silica. After sandblasting, all specimens were coated with a 2% or 4% acetic chitosan solution with a thickness of 1 mm. Then the specimens were dried for 120 min at 45 °C. The precipitated chitosan was neutralized with 1 mol NaOH. After neutralization, all specimens underwent abrasion tests using the tooth-brushing simulator with soft brushes (load 2N, 2 cycles/s, 32 °C, 3000 and 30,000 cycles). After each run, the specimen surfaces were analyzed for areas of remaining chitosan by digital planimetry under a light microscope. The best chitosan adhesion was found after sandblasting with aluminum oxide coated with silica (U-Test, p < 0.05) in both the PMMA and the PET groups. Hence, with relatively simple technology, a reliable bond of chitosan to PMMA and PET could be achieved.
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14

Ozdemir, Ali Yucel. "An Inquiry Into The Concept Of." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615034/index.pdf.

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This thesis makes a survey on conception of &ldquo
surface&rdquo
in the works of Peter Eisenman. In doing so, the concept of &ldquo
surface&rdquo
is discussed under three titles: &ldquo
Surface&rdquo
as an element of architectural vocabulary (as a formal element), as an analytical tool (as a grammar), and as a diagrammatic tool. Correspondingly, the thesis is intended to examine how &ldquo
surface&rdquo
is conceptualized and handled through the critical readings of Eisenman&rsquo
s writings, and projects are referred in order to support and visualize the discussions. In this context, Eisenman&rsquo
s dissertation, The Formal Basis of Modern Architecture (1963), reveals the definition of architectural surface in relation to the architectural language that is proposed by him. Through the formal analysis of Giuseppe Terragni&rsquo
s building, Casa Guiliani Frigerio, he utilizes surface as an analytical tool. Considering design processes of his projects, as discussed in the book Diagram Diaries (1999), surface becomes a dominant tool for generating architectural form. As a result, in this thesis, surface is evaluated in various aspects (as a formal, analytical and diagrammatic tool) that are essential for understanding of architectural form. In the case of Eisenman, its significance dominates the way of developing his architecture.
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15

Kinayoglu, Gokhan. "A Reconsideration Of The Concept Of Architectural Space In The Virtual Realm." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608818/index.pdf.

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The discovery of new geometries in the 19th century and the departure from an absolute to a relative understanding of space-time, together with the invention of higher dimensions have caused a shift towards the idealization of space. This new type of ideal space was called hyperspace. The counter-intuitive quality of hyperspace has opened up new formal possibilities and representation techniques in art and architecture. In a similar manner, with the introduction of computers, the virtual and immaterial quality of cyberspace has offered new design techniques and forms to architecture. Algorithmic design tools and the use of surface as the primary architectural element in cyberspace have caused a shift in the conception of space together with the way it is perceived. Taking its departure point from physical space, this thesis investigates the upper and lower dimensions of space in order to understand and analyze the current conception of architectural space in the virtual realm. Three types of spatial qualities are investigated in detail: the ideal characteristic of hyperspace, the visual medium of cyberspace and the algorithmic formation of hypospace.
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16

Lemesle, Charlotte. "Peintures auto-stratifiantes bio-sourcées : concept et mécanisme." Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1R012.

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L’objectif de cette thèse est de développer des revêtements auto-stratifiants biosourcés pour application ferroviaire. L’intérêt du procédé d'auto-stratification est de fournir un revêtement multifonctionnel en une seule étape d’application. Il offre une alternative au procédé conventionnel de revêtement multicouche car il répond aux contraintes environnementales et industrielles actuelles, telles que la diminution de la production de déchets, de la consommation électrique et du coût. Au cours de ces trois années de recherches, des revêtements auto-stratifiants à base de différentes résines époxyde bio-sourcées et de résines silicone ont été mis au point. Dans un premier temps, des modèles théoriques ont été utilisés pour prédire la stratification de différents systèmes résine époxyde/résine silicone. Cependant, aucune corrélation entre les résultats prédictifs et les niveaux de stratification obtenus expérimentalement n'a été établie. En effet, le phénomène d’auto-stratification est influencé par de nombreux facteurs qui ne sont pas pris en compte dans les modèles. L’influence de ces différents paramètres sur la stratification a donc été étudiée expérimentalement au cours de cette étude. Il en résulte que la nature, l’énergie de surface et la polarité des résines, la volatilité des solvants, la température de séchage et la nature du réticulant ont un impact sur le degré de stratification. Par la suite, les revêtements stratifiés en deux couches parfaitement distinctes ont été soumis à des tests de vieillissement accéléré afin de comparer leur résistance à l’humidité et au rayonnement UV à celle des revêtements classiques multicouches. Enfin, une analyse du cycle de vie comparative a été réalisée pour quantifier l'impact environnemental du procédé auto-stratifiant à base de résines bio-sourcées par rapport au procédé multicouche utilisant des résines pétro-sourcées
The goal of this PhD thesis is to design bio-based self-stratifying coatings for railway applications. This process provides a multifunctional coating in a single application step, offering an interesting alternative to conventional multi-layer coating process as it meets current environmental and industrial constraints, such as reduction of waste production, electricity consumption and cost. Over the last three years, self-stratifying coatings based on different bio-based epoxy and silicone resins were set up. As a first step, theoretical models were used to predict the layering of the different binary epoxy/silicon systems. However, the first experimental results obtained were not clearly correlated with the predicted ones in term of stratification level. Indeed, self-stratification phenomenon is influenced by many factors which are usually not taken into account in the theoretical models. The influence of these parameters on the stratification process was therefore investigated during this thesis. It led to the conclusion that the nature, the surface energy and the polarity of the resins, the solvent volatility, the curing temperature and the nature of the cross-linking agent have an impact on the degree of stratification. Thereafter, ageing tests were performed on the coatings showing two perfectly distinct stratified layers, to compare their resistance to humidity and UV radiation to those of conventional multi-layer coatings. Finally, a comparative Life Cycle Assessment was carried out to quantify the environmental impact of the self-stratifying process using bio-based resins compared to the multilayer process using oil-based resins
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17

Ushiama, Taketoshi, and Toyohide Watanabe. "A representation method of time-varying characteristics of entity on the basis of core-surface concept." IEEE, 1996. http://hdl.handle.net/2237/6929.

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18

Goss, Patricia. "THE INFLUENCE OF GRAPHIC ORGANIZERS ON STUDENTS' ABILITY TO SUMMARIZE AND COMPREHEND SCIENCE CONTENT REGARDING THE EARTH'S CHANGING SURFACE." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3786.

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The purpose of this action research project was to determine how my practice of using graphic organizers during instruction influenced my students' ability to summarize and comprehend significant fifth grade Earth Science content regarding the Earth's changing surface. A secondary purpose was to determine the students' perceptions of how concept mapping assisted in making connections to understand the fifth grade Earth Science content regarding the Earth's changing surface. The three processes used to collect data for this research were concept maps, focus groups and the pre- and post-test results. The themes that emerged were the ability to describe, categorize and classify details, the increased accuracy of the use of vocabulary and the memory of the concepts that students' ability to recall information and understand the Earth Science concepts as evidenced through summarization and comprehension through the pre- and post-test.
M.Ed.
Department of Teaching and Learning Principles
Education
K-8 Math and Science MEd
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19

Jeandel, Xavier. "Quelques aspects de la pulvérisation des liquides dans un système annulaire : instabilité de surface - encapsulation - concept LPP." Rouen, 2000. http://www.theses.fr/2000ROUES071.

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La problématique posée par la réduction des polluants et principalement de l'oxyde d'azote émis par les moteurs rencontres dans le secteur aéronautique a motivé ce travail de thèse. Notre intérêt s'est porte sur la formation du mélange comburant carburant et s'est élargi pour répondre à des questions plus fondamentales concernant la formation d'un spray à partir d'un système liquide annulaire bordé par un écoulement d'air d'énergie cinétique plus importante que le liquide. Le premier volet de ce travail porte sur l'étude d'un injecteur réel, dit "injecteur LPP", où la réduction de l'oxyde d'azote repose sur la réalisation d'un mélange comburant carburant en dessous de la stœchiométrie. Le nuage diphasique, forme de gouttelettes de kérosène entraînées par un écoulement d'air, est étudié expérimentalement au moyen de diagnostics optiques utilisant les propriétés de diffraction de la lumière. Plusieurs configurations des écoulements d'air sont étudiées et la structure du nuage à l'intérieur de l'injecteur est identifiée. Le second volet se place dans une problématique amont. Il permet d'approcher plus simplement le système liquide rencontré dans l'injecteur réel. Une nappe liquide de géométrie annulaire bordée par deux écoulements d'air coaxiaux est étudiée expérimentalement. Un schéma d'évolution de la nappe est proposé. L'ensemble des situations rencontrées est répertorié sous la forme d'une cartographie établie en fonction des paramètres du système liquide. Un modèle permet de prédire un temps caractéristique de l'évolution de la nappe. Le troisième et dernier volet aborde le problème d'instabilités de Kelvin-Helmholtz se développant à l'interface d'une nappe annulaire de liquide visqueux.
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20

Girard, Julien. "Validation sur le ciel du concept d'étoile laser polychromatique." Lyon 1, 2005. http://tel.archives-ouvertes.fr/docs/00/10/96/00/PDF/these_girard.pdf.

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La turbulence atmosphérique baisse considérablement la résolution angulaire au foyer des grands télescopes terrestres. L'optique adaptative (OA) corrige les distorsions de front d'onde mesurées à l'aide d'une source de référence brillante à proximité de la ligne de visée. Dans le domaine du visible, la probabilité de disposer d'une étoile naturelle de référence est infime. L'étoile laser remédie à ce problème sauf pour la pente du front d'onde (ou tilt) qui demeure non corrigée. L'étoile laser polychromatique permettra l'utilisation de l'OA avec une couverture totale du ciel. Basée sur le chromaticité du tilt, il s'agit de créer une référence multicolore dans l'atmosphère et de mesurer le tilt différentiel à deux longueurs d'onde distinctes pour remonter au tilt lui-même. Dans cette thèse, je décris l'expérience ATTILA, conçue pour prouver la faisabilité de ce concept en conditions astronomiques. Des observations menées à l'Observatoire de Haute-Provence sur des étoiles naturelles ont permis d'établir la relation de proportionnalité entre le tilt et le tilt différentiel pour la première fois. Un suivi en temps réel montre une bonne corrélation entre les deux signaux. La précision de mesure obtenue sur la pente (environ une tache d'Airy) ouvre la voie pour le futur démonstrateur ELP-OA avec lasers. Ce travail a nécessité une caractérisation approfondie d'un détecteur pourvu de la récente technologie EMCCD ainsi que le développement et les tests de sismomètres pendulaires dédiés à la mesure des vibrations angulaires de télescope
The atmospheric turbulence affects image quality and causes angular resolution losses at the focus of large ground based optical telescopes. Real time adaptive optics (AO) corrects wave front distortions measured with at least one bright reference source located within a tiny isoplanatic angle from the science object. At visible wavelengths, the probability to find one such natural star is ridiculously small. The laser guide star (LGS) solves the problem but the overall wavefront slope (referred here as tilt) remains undetermined. The Polychromatic Laser Guide Star will allow the use of AO with full sky coverage. Based on the tilt chromaticity, a multicolor reference spot is created in the upper atmosphere and the differential tilt is measured between two wavelengths to retrieve the tilt itself. In the present thesis, I describe ATTILA, an experiment designed to prove the feasibility of the concept in astronomical conditions. Observations carried on at Observatoire de HauteProvence on natural stars allowed us to establish the proportionality law that links the tilt and the differential tilt for the first time. A temporal monitoring of the two signals shows a good correlation. The accuracy obtained on the slope (about one Airy disk ) let us be optimistic for the future full ELP-OA demonstrator with lasers. This work required an in-depth characterization of a detector featuring the novel EMCCD technology as well as the implementation and tests of pendular seismometers dedicated to measure telescope angular vibrations
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21

Goss, Patricia A. "The influence of graphic organizers on students' ability to summarize and comprehend science content regarding the Earth's changing surface." Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002595.

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22

Consuegra, Zammit David. "Concept de gestion des eaux de surface : aspects méthodologiques et application au bassin versant de la Broye en Suisse /." [S.l.] : [s.n.], 1992. http://library.epfl.ch/theses/?display=detail&nr=1064.

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23

Girard, Julien. "VALIDATION SUR LE CIEL DU CONCEPT D'ETOILE LASER POLYCHROMATIQUE." Phd thesis, Université Claude Bernard - Lyon I, 2005. http://tel.archives-ouvertes.fr/tel-00106328.

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La turbulence atmosphérique baisse considérablement la résolution angulaire au foyer des grands télescopes terrestres. L'optique adaptative (OA) corrige les distorsions de front d'onde mesurées à l'aide d'une source de référence brillante à proximité de la ligne de visée. Dans le domaine du visible, la probabilité de disposer d'une étoile naturelle de référence est infime. L'étoile laser remédie à ce problème sauf pour la pente du front d'onde (ou tilt) qui demeure non corrigée. L'étoile laser polychromatique permettra l'utilisation de l'OA avec une couverture totale du ciel. Basée sur le chromaticité du tilt, il s'agit de créer une référence multicolore dans l'atmosphère et de mesurer le tilt différentiel à deux longueurs d'onde distinctes pour remonter au tilt lui-même. Dans cette thèse, je décris l'expérience ATTILA, conçue pour prouver la faisabilité de ce concept en conditions astronomiques. Des observations menées à l'Observatoire de Haute-Provence sur des étoiles naturelles ont permis d'établir la relation de proportionnalité entre le tilt et le tilt différentiel pour la première fois. Un suivi en temps réel montre une bonne corrélation entre les deux signaux. La précision de mesure obtenue sur la pente (environ une tache d'Airy) ouvre la voie pour le futur démonstrateur ELP-OA avec lasers. Ce travail a nécessité une caractérisation approfondie d'un détecteur pourvu de la récente technologie EMCCD ainsi que le développement et les tests de sismomètres pendulaires dédiés à la mesure des vibrations angulaires de télescope.
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24

Arora, Neha. "Contribution to the concept of micro factory : design of a flexible electromagnetic conveyor system." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2347.

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L’objectif de la thèse est de réaliser un système de convoyage flexible permettant de déplacer des micro-objets. Ce système pourra être amené à être intégré dans une micro-usine ce qui nécessite une forte reconfigurabilité et une faible consommation d’énergie. Ces deux critères ont donc été considérés lors de la conception du système de convoyage. Ce dernier est basé sur un actionneur planaire électromagnétique, développé au sein du laboratoire Roberval, et sur une surface intelligente composée de 5 × 5 cellules élémentaires permettant chacune de déplacer la partie mobile dans les deux directions du plan et des rotations autour de l'axe perpendiculaire au plan. Un modèle analytique de l’actionneur a été développé afin de calculer les efforts électromagnétiques ainsi que le déplacement de la partie mobile. Ce modèle a été utilisé lors de la phase de conception du système de convoyage. Un prototype expérimental a ensuite été fabriqué et testé ce qui a permis de valider le principe de fonctionnement proposé. Des tests expérimentaux ont montré la possibilité de réaliser des déplacements de grande étendue dans les deux directions du plan. De multiples tests expérimentaux (pilotage en boucle ouverte, caractérisation des performances telles que rectitude de déplacement, répétabilité de positionnement, charge déplaçable, …) a été réalisée afin de qualifier les performances du système de convoyage. Les points sur la réalisation : - Une modélisation statique sous RADIA a été développée afin de concevoir la surface intelligente notamment la zone de transition entre deux cellules voisines. Une modélisation dynamique réalisée sous MATLAB a permis de simuler le comportement d’un moteur en boucle ouverte et en boucle fermée. - Un prototype de surface intelligente, composé d’un circuit imprimé multicouches (4 couches) de dimensions 130 mm x 130 mm, a été conçu sous EAGLE software. L’influence de la distance entre les deux premières couches a été étudiée à l’aide des modèles développés afin d'assurer un déplacement uniforme dans les deux directions. - Un test expérimental avec LABVIEW interface d'une cellule élémentaire de la surface intelligente avec une partie mobile composée de deux moteurs magnétiques orthogonaux a été réalisé et a permis de valider le fonctionnement du système de convoyage dans les deux directions du plan. - Une autre série de tests avec LABVIEW interface a été réalisée afin de valider expérimentalement le déplacement de la partie mobile avec la surface intelligente au niveau des zones de transition entre les cellules élémentaires. Ces tests expérimentaux ont montré des déplacements de grande étendue dans les deux directions du plan et de rotation autour de l'axe perpendiculaire au plan. Des déplacements de grande étendue et des rotations de la partie mobile ont été mesurés à l’aide d’une méthode de traitement d'image réalisée sous MATLAB. - Parallèlement, on a étudié un capteur à déplacement optique à haute résolution qui peut être intégré dans le convoyeur. Un algorithme robuste pour le traitement du signal de capteur à fibres optiques à haute résolution pour mesurer de déplacement est développé. Dans cet algorithme, la position optimale de la partie mobile est déterminée pour obtenir un basculement sans arrêt entre les sondes et l'algorithme est implémenté sous MATLAB et validée par la mise en œuvre des signaux expérimentaux. Ces travaux de thèse ont été publiés dans une revue internationale (Computers in Industry (COMIND)) et présentés dans des congrès internationaux (IEEE Sensors, REM Mechatronics, AIM, IWMF) pendant les années 2011 à 2016
The aim of the thesis is to provide a flexible conveyor system for moving micro-objects. The system may need to be integrated into a micro-factory which requires high reconfigurability and low power consumption. These two criteria have been considered in the design of the conveyor system. The conveyor is based on a planar electromagnetic actuator developed in the Laboratoire Roberval of the UTC, and on smart surface composed of 5 x 5 unit cells; each ceii moves th movable part in the two directions of the plane. An analytical model of the actuator has been developed in order to calculate the electromagnetic forces and the displacement of the mobile part. This modei has been used during the design phase of the conveying system. An experimental prototype is then manufactured and tested which has validated the proposed principle of operation. Experimental tests have shown the ability to perform wide area displacement in both directions of the plane. Numerous experimental tests (control in open loop and closed loop performance characterization as straightness of movement, position repeatability, coupled- decoupled analysis...) have been done to qualify the performance of the conveyor system. Experiments for rotations about the axis perpendicular to the olane have also been performed successfully. Work synthesis: - Static modeling under RADIA was developed in order to design the conveyor surface especially for the transitio zone between two neighboring cells. A dynamic modeling under MATLAB allowed to simulate the behavior of single axis motor in open loop and closed loop control. - A conveyor surface prototype, consisting of a multilayer printed circuit board (4 layers) of dimensions 130 mm x 130 mm, was designed under EAGLE software. The influence of the distance between the first two layers was studied using the developed models to ensure uniform displacement in both the directions. - The experimental tests (with LABVIEW interface) of an elementary cell of the intelligent surface with a moving part composed of two orthogonal magnetic motors has been carried out that allowed to validate the operation of the conveying system in both directions of the plane. - Another series of tests with LABVIEW interface were carried out in order to validate experimentally the displacement of the mobile part with the smart surface at the transition zones between the elementary cells. - These experimental tests showed displacements of great extent in the two directions of the plane and of rotation about the axis perpendicular to the plane. - Long displacements and rotations of the moving part were measured using image processing algorithm developed in MATLAB. - At the same time, a high resolution fiber optic displacement sensor was studied that can be integrated into the conveyor surface locally for the precise positioning. A robust signal processing algorithm for high resolution displacement measurement was developed. In this algorithm, - The optimum position of the movable part is determined in order to obtain a continuous switching betwee the two fiber optic probes ; - The usable parts of the signals obtained from two probes were then filtered to measure the displacement using interpolation method ; The algorithm is implemented under MATLAB and validated by the implementation of the experimental signals. The work have been published in an international journal (Computers in Industry (COMIND)) and presented at international congresses (IEEE Sensors, REM Mechatronics, AIM, IWMF) during the years 2011 to 2016
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25

Huguet, Anne. "Un nouveau concept de séparation actinides-lanthanides en milieu sel fondu : mise en oeuvre d'une cathode liquide à surface renouvelée." Phd thesis, Université Joseph Fourier (Grenoble), 2009. http://tel.archives-ouvertes.fr/tel-00539606.

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Ces travaux s'inscrivent dans le cadre des recherches menées sur l'évaluation des procédés pyrochimiques pour la séparation actinides-lanthanides. Ils concernent plus précisément un coeur de procédé consistant en la réduction, sur cathode liquide, des actinides dissous en milieu sel fondu. Cette technique présente un certain potentiel pour un scénario de « gestion groupée ». L'objectif de ces travaux est de proposer un procédé de séparation électrolytique qui améliorait, à la fois, les performances d'extraction des An, et de séparation An-Ln. L'amélioration de la sélectivité passe par la mise en oeuvre d'autres solvants que ceux explorés jusqu'à présent. Une étude méthodologique et thermodynamique nous a conduits à sélectionner une combinaison solvant/substrat cathodique prometteuse : fluorures fondus et bismuth liquide. Cette étape a été suivie d'une validation expérimentale (sur néodyme), permettant de s'assurer aussi bien de la faisabilité de mise en oeuvre des systèmes, que de la pertinence de nos prévisions. Les performances d'extraction pourraient, quant à elles, se voir améliorées par la mise en oeuvre d'un renouvellement de l'interface sel/cathode liquide. Il s'agit alors de répondre à la faisabilité d'une électrolyse dynamique sur gouttes de métal liquide. L'étude de la transposition de cette technologie aux milieux présélectionnés nous a conduits à mettre au point un petit dispositif dédié aux études d'écoulement, ainsi qu'une méthode de détermination des tensions interfaciales à haute température. Ces travaux démontrent que le principe de séparation sur cathode liquide à surface renouvelée ne présente pas de point rédhibitoire. Néanmoins, une validation en actif et une optimisation de la technologie sont nécessaires pour compléter l'évaluation de cette technique séparative innovante.
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26

Abroug, Foued. "Effet des défauts d’usinage sur la tenue en fatigue de pièces aéronautiques." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0016/document.

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Il été prouvée dans plusieurs études de la littérature que la taille d'un composant affecte sa tenue en fatigue et cette tendance est plus prononcée dans le régime de fatigue à grand nombre de cycles. Plus précisément, une baisse de la limite de fatigue est observée et est souvent expliquée par l’augmentation, avec l’augmentation du volume sollicité, de la probabilité de trouver un défaut critique ou une zone plus faible dans le matériau. Le présent mémoire fait partie d'un projet de recherche français (QUAUSI) regroupant plusieurs partenaires industriels et académiques qui vise à contrôler la qualité d'usinage des composants structuraux d'avions. Un des défis consiste à définir un critère approprié d'acceptabilité de défauts pour la conception en FGNC. Le critère doit être capable de prendre en compte une large gamme de défauts de surface et de composants de tailles et de géométries différentes. L'objectif principal étant de mieux comprendre l'impact des états de surface périodiques (caractéristique du type d'usinage utilisé) sur la limite de fatigue, Il a fallu d'abord vérifier si un effet de taille peut être observé quand un nombre croissant de défauts de surface simples sont introduits à la surface d'échantillons polis. Le matériau d’étude est l’alliage d'aluminium 7050 (Al Zn6CuMgZr). Une grande campagne d'essais de fatigue sous charge de flexion plane à R=-1 est effectuée sur des éprouvettes présentant des défauts hémisphériques, de différents tailles et nombres, et des états de surface usinés. Les résultats des essais ont permis de caractériser à la fois l'effet Kitagawa et l'effet d'échelle sur la tenue fatigue. Une approche probabiliste basée sur le concept du maillon le plus faible associé à un critère d'amorçage de fissure de fatigue approprié est utilisée pour prendre en compte la répartition des contraintes et la taille du volume fortement sollicité. Les prédictions utilisant des simulations EF montrent un bon accord avec les résultats expérimentaux et illustrent l'importance de prendre en compte l'effet d'échelle lors de la conception de composants contenant différents types de défauts de surface ou de motifs de rugosité.Mots-clés : Défaut de surface, fatigue à grand nombre de cycles, diagramme de Kitagawa-Takahashi, Le plus faible concept de lien, alliage AA7050
The size of a component has been proved in several studies of the literature to affect the fatigue strength and this trend is known to be more pronounced in the High Cycle Fatigue regime. More exactly a drop of the fatigue limit is observed and this evolution is very often explained by the probability to find a critical defect or a weakest zone in the material as the stressed volume rises. The present manuscript is part of a French research project gathering several industrial and academic partners that aims to control the machining quality of aircraft structural components. For one part of the project the challenge is to define a proper defect acceptability criterion for HCF design purpose. It must be able to account for a large range of surface defects and of component sizes and geometries. Even though the primary objective was to better understand the impact of periodic surface micro-geometry patterns (characteristic of the type of machining used) on the fatigue limit, we thought that it was first necessary to check if a size effect can be observed when an increasing number of artificial simplified surface defects are introduced at the surface of smooth specimens. The aeronautical material under investigation is a 7050 Aluminum alloy (Al Zn6CuMgZr). A large fatigue testing campaign under fully reversed plane bending loading is undertaken on specimens with artificial surface hemispherical defects. Defect number varies from 1 to 44 per specimen whereas their size ranges from 60 µm to 800 µm. Testing results allow the characterization of both Kitagawa effect and scale effect on the fatigue response. A probabilistic approach based on the weakest link concept together with a proper fatigue crack initiation criterion is used to account for the stress distribution and the size of the highly stressed volume. Predictions using FE simulations show a good agreement with experimental results and illustrate the importance of taking the scale effect into account while designing components containing different types of surface defects or roughness patterns.Keywords : Surface defect, HCF, Kitagawa-Takahashi diagram, Weakest link concept, AA7050 alloy
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27

Taylor, Amy Rebecca. "Students' and Teachers' Conceptions of Surface Area to Volume in Science Contexts: What Factors Influence the Understanding of the Concept of Scale?" NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-03022008-181319/.

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The National Science Education Standards emphasize teaching unifying concepts and processes such as basic functions of living organisms, the living environment, and scale (NRC, 1996). Since the relationship of surface area to volume is a pervasive concept that can be found throughout different sciences, it is important for students to not only understand the association of the two, but to also be able to apply it to various situations. The purpose of this study is to investigate the factors that influence the understanding of the concept of scale involving surface area to volume relationships. The first study reported here describes a pilot study with middle school participants in which the correlation between proportional reasoning ability and a studentâs ability to understand surface area to volume relationships was explored. The results of this study showed there was a statistically significant correlation between proportional reasoning scores and the surface area to volume posttest scores. This correlation was explored further in the second study in which middle school studentsâ, high school studentsâ, and science teachersâ abilities in proportional reasoning, visual-spatial skills, and understanding surface area to volume relationships were assessed. Regression results indicated that all participantsâ proportional reasoning and visual-spatial scores could be a possible predictor for oneâs ability to understand surface area to volume relationships. Discussion of the results is followed by implications for teaching scale concepts such as surface area to volume in the science classroom.
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28

Janati, Idrissi Abderrazak. "Caractérisation physico-chimique des alumines par le concept d'objets fractals." Poitiers, 1988. http://www.theses.fr/1988POIT2305.

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29

Zaïm-Bilheux, Hassina. "Design and initial comparative evaluation studies of conventional "surface" and new concept "volume"-type, all permanent magnet electron cyclotron resonance (ECR) ion sources." Versailles-St Quentin en Yvelines, 2003. http://www.theses.fr/2003VERS0008.

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Les sources d'ions à "Résonance cyclotronique d'électrons"(RCE)constituent, à l'heure actuelle, le meilleur choix parmi les sources existantes en ce qui concerne la production des faisceaux continus d'ions positifs hautement chargés. Ces sources produisent des rapports charge-sur-masse très élevés (jusqu'à 0,35 pour l'uranium) et des intensités par charge du [microampère] au mA, ce qui fait leur succès auprès des accélérateurs d'ions lourds à haute énergie. Depuis la naissance du concept dans les années 1970, leurs performances ont régulièrement progressé (amélioration du confinement du plasma, utilisation d'ondes électromagnétiques à fréquence élevée, amélioration de la qualité du vide, addition d'électrons "froids", disque polarisé, effet Malter et utilisation d'un gaz plus léger). Récemment, il a été suggéré que les performances des sources RCE pouvaient être notablement améliorées en augmentant le volume de résonance soit en étendant la zone d'induction résonante soit en élargissant la bande HF de l'onde. Une source RCE à aimants permanents fonctionnant à la fréquence 6 GHz, avec la possibilité de créer un large volume de plasma résonant, a été dessinée, construite et testée au Laboratoire National d'Oak Ridge (ORNL), en avant-première. Le champ magnétique est flexible, de sorte qu'il peut être configuré en champ plat("volume") ou en champ conventionnel à B minimum ("surface") afin de pouvoir comparer directement les performances des deux types de sources dans des conditions expérimentales équivalentes. Les résultats expérimentaux préliminaires montrent que la source à champ plat surpasse celle en champ conventionnel, en terme de distribution de charge et d'intensité
ECR ion sources are clearly the best choice of existing sources for the generation of CW beams of highly charged ions, and therefore, they are at a premium for high-energy accelerator-based applications. The technology of the source has slowly but steadily advanced over the past several years (improvement in plasma confinement; use of very high frequency microwave radiation; improvement in vacuum quality; supplementing their plasma discharges with cold electrons; biased disks; and gas mixing effect). Recently, it has been suggested that their performances can be significantly further enhanced by incresing the physical sizes of their ECR zones in relation to the sizes of their plasma volumes (spatial and frequency domain methods). A 6 GHz, all-permanent magnet ECR ion source with à large resonant plasma volume has been designed, constructed and initially tested at the Oak Ridge National Laboratory. The conventional minimum-B("surface") resonance conditions so that direct comparaisons of the performances of the two source types can be made under identical operating conditions. According to initial test results, the flat-B source performs better than its conventionnal-B conterpart, in terms of charge-state distribution and intensity within a particular charge-state. This is attributable to the very large ECR zones present in the source and their locations with respect to the launch direction of the RF power
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30

Hanekamp, Patrick [Verfasser], and Frank-Michael [Akademischer Betreuer] Matysik. "Development and application of an experimental concept for surface characterization of semiconductor based substrates using scanning electrochemical microscopy / Patrick Hanekamp ; Betreuer: Frank-Michael Matysik." Regensburg : Universitätsbibliothek Regensburg, 2020. http://d-nb.info/1207153222/34.

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31

Cole, Robert Pierre. "A reality running like a subterranean river under the surface, the place of the Jungian concept of individuation in the non-Deptford writings of Robertson Davies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0002/NQ29026.pdf.

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32

Sang, Shengbo [Verfasser], Hartmut [Akademischer Betreuer] Witte, Klaus [Akademischer Betreuer] Liefeith, and Theodor [Akademischer Betreuer] Doll. "An approach to the design of surface stress-based PDMS micro-membrane biosensors - concept, numerical simulations and prototypes / Shengbo Sang. Gutachter: Klaus Liefeith ; Theodor Doll. Betreuer: Hartmut Witte." Ilmenau : Universitätsbibliothek Ilmenau, 2010. http://d-nb.info/1010814516/34.

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33

Moreira, Baltar Bellemain Paula. "Enseignement et apprentissage de la notion d'aire de surfaces planes : une étude de l'acquisition des relations entre les longueurs et les aires au collège." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10193.

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Cette recherche porte sur la construction du concept d'aire chez les élèves de collège et plus particulièrement sur l'acquisition des relations entre les longueurs et les aires, leur coordination lors de la mise en place des formules d'aire et leur différentiation dans les problèmes d'aire et de périmètre. Dans la première partie on présente les fondements de la recherche du point de vue mathématique, de celui de l'enseignement actuel en France et des travaux antérieurs sur le thème. Ces études préalables permettent de placer la problématique dans le contexte plus large des recherches en didactique. La deuxième partie est consacrée a une étude des situations problème autour du concept d'aire de surfaces planes, développée dans le cadre de la théorie des champs conceptuels. La construction d'une classification des situations, avec mise en évidence des procédures de traitement possibles, ainsi que l'élaboration d'un répertoire de théorèmes en acte, apportent de nouveaux éléments d'analyse des difficultés conceptuelles rencontrées dans l'apprentissage du concept d'aire au collège. La troisième partie est dédiée a la présentation de l'ingénierie didactique réalisée en classe de cinquième. Les résultats confirment la pertinence de l'approche de l'aire en tant que grandeur, adoptée dans le travail. Cette approche favorise en particulier la mise en cause des formules fausses et l'acquisition des formules de l'aire des surfaces usuelles. La prise en compte des situations dans lesquelles le point de vue dynamique intervient, construites dans l'environnement cabri-géomètre, favorise de plus: - la mise en cause du théorème en acte selon lequel l'aire et le périmètre d'un parallélogramme varient forcement dans le même sens, - un début d'utilisation, par les élèves, de la formule d'aire d'un parallélogramme avec une lecture liée au domaine des fonctions - usage plus élabore que celui d'un moyen de calcul
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34

Peltier, Fabienne. "Influence du transport de matière sur la compétition entre la corrosion d'une surface d'un alliage d'aluminium mis à nu et le relâchement de peintures fonctionnalisées par des pigments inhibiteurs : validation d'un concept de capteur de corrosion." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS042/document.

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En aéronautique, les structures en alliage d’aluminium 2024 sont protégées par un primaire anticorrosion fonctionnalisé par des pigments inhibiteurs permettant une cicatrisation rapide de la surface de l’alliage exposée à l’environnement extérieur lors d’un endommagement mécanique superficiel. Compte tenu de la perte de fonctionnalité des primaires par lessivage, il semble nécessaire d’évaluer les risques d’amorçage de la corrosion. En pratique, il a été envisagé de mettre en place des capteurs dits de « corrosion ».L’objectif de ce travail était de comprendre le fonctionnement d’un capteur censé représenter l’endommagement d’une peinture, dont le concept repose sur la compétition entre l’amorçage de la corrosion d’une surface d’un alliage d’aluminium mis à nu et le relâchement d’inhibiteurs (provenant de la peinture). Le comportement de l’alliage 2024 et de solutions solides (constituant le capteur) a été étudié en milieu chloruré en présence ou non d’inhibiteurs à différentes concentrations. En variant la taille d’électrodes peintes exposées sur leur tranche, on a pu quantifier l’efficacité des inhibiteurs sur ces deux types de matériaux, en détectant l’amorçage de la corrosion ou son inhibition, par mesure de pH de surface. Cette analyse chimique couplée à des observations in situ, a permis de déterminer les étapes limitantes qui définissent la compétition entre corrosion et passivation dans le cas de l’alliage 2024. Ces différentes analyses ont montré que, pour quantifier cette compétition, la cinétique d’amorçage de la corrosion microstructurale constitue un élément clé qui ne peut pas être représenté par la réponse des électrodes du capteur constituées d’une solution solide. L’existence d’une distance maximale entre la source d’inhibiteurs et la zone pouvant être passivée a pu être confirmée par la simulation du transport des espèces inhibitrices qui dépend principalement du régime de lessivage du primaire
The conventional aircraft paint scheme for corrosion protection of aluminum structures is partly based on application of a primer containing inhibitors. In such coatings, release of the inhibiting species enables fast healing of a bare metal surface after a mechanical damage of the protective layers. Nevertheless, considering possible depletion of inhibitors by uncontrolled leaching, it appears important to estimate the corrosion risk integrating “corrosion” sensors in the structure. The objective of this work was to understand the operating mode of a sensor simulating a damaged paint coating whose concept is based on the competition between the triggering of localized corrosion and the passivation of a bare 2024 alloy. The behavior of this massive alloy and Al-Cu solid solutions (the active metallic slots of the sensor) was studied in chloride solution in presence or not of inhibitor ions at different concentrations.Varying the size of a cut-edge electrode coated on both sides, the effectiveness of these inhibitors was demonstrated detecting the microstructural corrosion triggering or its inhibition, by mapping surface pH. Combining these chemical probing with in situ observations it was possible to confirm the nature of the limiting steps controlling the competition between corrosion and passivation. These analyzes highlighted that to quantify this competition, the triggering of the microstructural corrosion represents a key factor which is not possible to mimic by the response of the solid solutions.The existence of a threshold value for the distance between the inhibitor source and the area to be passivated has been confirmed by simulating the mass transport of inhibiting species which appear to be dependent of the release rate of inhibitors
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TAKAGI, Kenji, 光夫 野津, Mitsuo NOZU, 利弘 野田, Toshihiro NODA, 敏浩 高稲, Toshihiro TAKAINE, and 健次 高木. "水～土連成計算を用いた砂杭拡径による砂地盤の締固めメカニズムの一考察." 土木学会, 2001. http://hdl.handle.net/2237/8642.

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36

Namutebi, May. "Some Aspects of Foamed Bitumen Technology." Licentiate thesis, KTH, Väg- och banteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32944.

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Although foamed bitumen has been widely applied in pavement construction some of its aspects are still not yet understood. In this study, some of these aspects including: effects of the foaming process on binder chemistry, characterization of foamed bitumen and development of a rational method to optimize foam characteristics, evaluation of aggregate particle coating within foamed bitumen treated materials, and development of a gyratory compaction procedure for laterite gravels treated with foamed bitumen were addressed. The effects of the foaming process on bitumen chemistry were investigated using Fourier transform infrared spectroscopy techniques. Also, foam characteristics of three binders were established and a rational method to optimize foam characteristics proposed. Aggregate particle coating with foamed bitumen was studied using the concepts of surface energy and Rice density. In addition a gyratory laboratory compaction procedure for laterite gravels treated with foamed bitumen was established using the modified locking concept. Infrared techniques have shown that foaming does not cause any changes in the binder chemistry, suggesting that foaming may be a physical process. Further, foam characteristics are greatly influenced by binder viscosity. Also, the equiviscous temperature seems to produce foam with optimum foam characteristics. Rice density results showed that aggregate size fraction, binder expansion ratio and viscosity influenced aggregate particle coating. Surface energy results revealed that foamed bitumen exhibited better coating attributes than neat bitumen. A new compaction procedure for laterite gravels treated with foamed bitumen based on the modified locking point was developed.
QC 20110427
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37

Guest, Simon David. "Deployable structures : concepts and analysis." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336615.

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Dragaš, Milan. "Advanced concepts in vertical cavity surface emitting lasers." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404105.

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39

Hattar, Susan. "Concept de surfaces biomimétiques pour stimuler in vitro l'ostéogenèse." Paris 7, 2004. http://www.theses.fr/2004PA07A001.

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En chirurgie dentaire, le praticien est souvent confronte à des pertes osseuses suite a des extractions dentaires ou des parodontites. Depuis longtemps, des tentatives ont été réalisées pour trouver le substitut idéal de Vos qui ~OUIT3 remplacer non seulement la structure mats aussi la fonction du tissu osseux. Grâce aux progrès de l'ingénierie tissulaire de l'utilisation des surfaces biomimétiques, de nouvelles perspectives thérapeutiques émergent. Parmi ces matériaux. Les matériaux qualifiés de bioactifs ont été proposés pour stimuler l'ostéogenèse. Malgré le fait que ces matériaux soient largement utilisés dans les applications cliniques, le mécanisme exact d'action de ces matériaux reste mal connu. L'objectif de notre travail, a été dans un premier temps, d'essayer d'approfondir nos connaissances sur les effets de tels matériaux sur le comportement des cellules ostéoblastiques in vitro. Plus précisément, nous nous sommes proposés à étudier l'influence des verres bioactifs 45S5 sur l'expression de gènes clés du phénotype ostéoblastique afin de voir l'influence sur la différenciation cellulaire, au niveau génétique Dans un deuxième temps, nous avons voulu tester l'effet de la modification des surfaces de biomatériaux afin de voir si nous pouvions améliorer la bioactivité de ces verres. Une première étude a consisté à étudia l'influence des verres bioactifs seuls ou incubés dans un tampon de tris (pour préfabriquer la couche bioactive) sur les cellules de la lignée humaine MG63. Nos résultats morphologiques elles analyses par RT-PCR montrent un maintien du phénotype ostéoblastique et une expression quasi équivalente dans les cultures bioactives comparés au témoin bioinerte. Dans un deuxième temps nous avons cultivé des cellules murines de la lignée MC3T3. E1 en présence de verres bioactifs seuls ou recouverts de protéines amélaires (Emdogain® ) Nos résultats morphologiques montrent une différenciation cellulaire ainsi qu'une minéralisation plus importante dans les cultures bioactives. D'autre part, le taux de protéines s'est avéré plus important, au 20ème jour, lorsque les granules de verres bioactifs étaient associés à l'Emdogain®. Les résultats par Northern Blot montrent une expression plus importante des gènes clés tels que Runx2, BSP et l'ostéocalcine dans les deux cultures bioactives par rapport au témoin. La dernière partie de ce travail a consisté à évaluer l'effet d'une nouvelle génération de verres bioactifs issues de la technique de solgel sur l'ostéogenèse, à partir de cultures ostéoblastiques primaires murines. Ces verres possèdent une bioactivité plus importante à cause de leur composition et leur structure hautement poreuse. Les résultats démontrent une stimulation des paramètres de différenciation ostéoblastique. Cela a été confirmé par une formation plus précoce et plus importante des nodules osseux dans les cultures solgel par rapport aux verres bioinertes. De plus, l'expression des marqueurs phénotypique principaux, tels que la phosphatase alcaline, la bone sialoprotéine et surtout l'ostéocalcine a été stimulée dans les cultures solgel. L ‘ensemble de ces résultats montre que les verres bioactifs sont capables de stimuler l'ostéogenèse in vitro Cet effet a été démontré plutôt au niveau de l'expression des gènes clés du phénotype ostéoblastiques. Par ailleurs, il semblerait que la combinaison des verres bioactifs à l'Emdogain® stimule davantage les paramètres de différenciation.
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40

Tobgay, Sonam. "Novel concepts for RF surface coils with integrated receivers." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0419104-141545.

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41

Shah, Raza. "Property inference decision-making and decision switching of undergraduate engineers : implications for ideational diversity & fluency through movements in a Cartesian concept design space." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/278700.

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Design fixation is a phenomenon experienced by professional designers and engineering design students that stifles creativity and innovation through discouraging ideational productivity, fluency and diversity. During the design idea and concept generation phase of the design process, a reliance on perceptual surface feature similarities between design artefacts increases the likelihood of design fixation leading to design duplication. Psychologists, educators and designers have become increasingly interested in creative idea generation processes that encourage innovation and entrepreneurial outcomes. However, there is a notable lack of collaborative research between psychology, education and engineering design particularly on inductive reasoning of undergraduate engineering students in higher education. The data gathered and analysed for this study provides an insight into property inference decision-making preferences and decision switching (SWITCH) patterns of engineering undergraduates under similarity-based inductive judgements [SIM] and category-based inductive judgements [CAT]. For this psychology experiment, property induction tasks were devised using abstract shapes in a triad configuration. Participants (N = 180), on an undergraduate engineering programme in London, observed a triad of shapes with a target shape more similar-looking to one of two given shapes. Factors manipulated for this experiment included category alignment, category group, property type and target shape. Despite the cognitive development and maturation stage of undergraduate engineers (adults) in higher education, this study identified similarity-based inductive judgements [SIM] to play a significant role during inductive reasoning relative to the strength of category-based inductive judgements [CAT]. In addition to revealing the property inference decision-making preferences of a sample of undergraduate engineers (N = 180), two types of switch classification and two types of non-switch classification (SWITCH) were found and named SIM_NCC, SIM-Salient, Reverse_CAT and CAT_Switching. These different classifications for property inference switching and non-switching presented a more complex pattern of decision-making driven by the relative strength between similarity-based inductive judgements [SIM] and category-based inductive judgements [CAT]. The conditions that encouraged CAT_Switching is of particular interest to design because it corresponds to inference decision switching that affirms the sharing of properties between dissimilar-looking shapes designated as category members, i.e., in a conflicting category alignment condition (CoC). For CAT_Switching, this study found a significant interaction between a particular set of conditions that significantly increased the likelihood of property inference decisions switching to affirm the sharing of properties between dissimilar-looking shapes. Stimuli conditions that combined a conflicting category alignment condition (where dissimilar-looking shapes belong to the same category) with category specificity, a causal property and a target shape with merged (or blended) perceptual surface features significantly increased the likelihood of a property inference decision switching. CAT_Switching has important implications for greater ideational productivity, fluency and diversity to discourage design fixation within the conceptual design space. CAT_Switching conditions could encourage more creative design transformations with alternative design functions through inductive inferences that generalise between dissimilar artefact designs. The findings from this study led to proposing a Cartesian view of the concept design space to represent the possibilities for greater movements through flexible and expanding category boundaries to encourage conceptual combinations, greater ideational fluency and greater ideational diversity within a configuration design space. This study has also created a platform for further research into property inference decision-making, ideational diversity and category boundary flexibility under stimuli conditions that encourage designers and design students to make inductive generalisations between dissimilar domains of knowledge through a greater emphasis on causal relations and semantic networks.
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42

Wu, Dongping. "Novel concepts for advanced CMOS : Materials, process and device architecture." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3805.

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The continuous and aggressive dimensional miniaturization ofthe conventional complementary-metal-oxide semiconductor (CMOS)architecture has been the main impetus for the vast growth ofIC industry over the past decades. As the CMOS downscalingapproaches the fundamental limits, unconventional materials andnovel device architectures are required in order to guaranteethe ultimate scaling in device dimensions and maintain theperformance gain expected from the scaling. This thesisinvestigates both unconventional materials for the gate stackand the channel and a novel notched-gate device architecture,with the emphasis on the challenging issues in processintegration.

High-κ gate dielectrics will become indispensable forCMOS technology beyond the 65-nm technology node in order toachieve a small equivalent oxide thickness (EOT) whilemaintaining a low gate leakage current. HfO2and Al2O3as well as their mixtures are investigated assubstitutes for the traditionally used SiO2in our MOS transistors. These high-κ filmsare deposited by means of atomic layer deposition (ALD) for anexcellent control of film composition, thickness, uniformityand conformality. Surface treatments prior to ALD are found tohave a crucial influence on the growth of the high-κdielectrics and the performance of the resultant transistors.Alternative gate materials such as TiN and poly-SiGe are alsostudied. The challenging issues encountered in processintegration of the TiN or poly-SiGe with the high-k are furtherelaborated. Transistors with TiN or poly-SiGe/high-k gate stackare successfully fabricated and characterized. Furthermore,proof-of-concept strained-SiGe surface-channel pMOSFETs withALD high-κ dielectrics are demonstrated. The pMOSFETs witha strained SiGe channel exhibit a higher hole mobility than theuniversal hole mobility in Si. A new procedure for extractionof carrier mobility in the presence of a high density ofinterface states found in MOSFETs with high-κ dielectricsis developed.

A notched-gate architecture aiming at reducing the parasiticcapacitance of a MOSFET is studied. The notched gate is usuallyreferred to as a local thickness increase of the gatedielectric at the feet of the gate above the source/drainextensions. Two-dimensional simulations are carried out toinvestigate the influence of the notched gate on the static anddynamic characteristics of MOSFETs. MOSFETs with optimizednotch profile exhibit a substantial enhancement in the dynamiccharacteristics with a negligible effect on the staticcharacteristics. Notched-gate MOSFETs are also experimentallyimplemented with the integration of a high-κ gatedielectric and a poly-SiGe/TiN bi-layer gate electrode.

Key words:CMOS technology, MOSFET, high-κ, gatedielectric, ALD, surface pre-treatment, metal gate, poly-SiGe,strained SiGe, surface-channel, buried-channel, notchedgate.

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43

BARACCO, FLAVIO. "HERMANN WEYL AND HIS PHENOMENOLOGICAL RESEARCHES WITHIN INFINITESIMAL GEOMETRY." Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/638166.

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The present work focuses on the mathematical and philosophical works of Hermann Weyl (1885-1955). Weyl was a leading mathematician at the beginning of the twentieth century and his major contributions have concerned several fields of research, both within pure mathematics and theoretical physics. Many of them were pioneering works at that time and, most of all, they were carried out in the light of his peculiar philosophical view. As few mathematicians of his time, Weyl was able to manage both scientific and philosophical issues with an impressive competence. For this reason he represented a very peculiar figure among scientists and mathematicians of his time. This dissertation aims to clarify these works both from a philosophical and a mathematical perspective. Specifically, I will focus on those works developed through the years 1917-1927. The first chapter aims to shed some light on the philosophical reasons that underlie Weyl's foundational studies during this period. I will explore these works especially with respect his attempt to establish a connection between a descriptive analysis of phenomena and their exact determination. I will focus both on his mathematical formulation of Euclidean space and on his analysis of phenomenal continuum pointing out the main features of these studies. Weyl's investigations on the relations between what is intuitively given and the mathematical concepts through which we seek to construct the given in geometry and physics do not seem to be carried out by chance. These investigations indeed could be better understood within the phenomenological framework of Husserl's philosophy. Husserl's distinction between descriptive and exact concepts delineates the difference between a descriptive analysis of a field of inquiry and its exact determination. Clarifying how they are related is not an easy task. Nevertheless, Husserl points out that a connection might be possible if we were able to establish a connection by means of some idealizing procedure intuitively ascertained. Within this phenomenological framework we should interpret Weyl's investigations on the relation between phenomenal knowledge and theoretical construction. In the second chapter I will focus on Weyl's mathematical account of the continuum within the framework of his pure infinitesimal geometry developed mainly in \emph{Raum-Zeit-Materie}. It deserves a special attention. Weyl indeed seems to make use of infinitesimal quantities and this fact appears to be rather odd at that time. The literature on this issue is rather poor. For this reason I've tried to clarify Weyl's use of infinitesimal quantities considering also Weyl's historical context. I will show that Weyl's approach has not to be understood in the light of modern differential geometry. It has instead to be understood as a sort of algebraic reasoning with infinitesimal quantities. This approach was not so unusual at that time. Many mathematicians, well-known to Weyl, were dealing with kind of mathematics although many of these studies were works in progress. In agreement with that, Weyl's analysis of the continuum has to be understood as a work in progress as well. In the following Weyl's studies in combinatorial topology are proposed. I will then suggest that both these approaches should be understood within the phenomenological framework outlined in the first chapter. The latter, however, attempts to establish a more faithful connection between a descriptive analysis of the continuum and its exact determination and for this reason it can be regarded as an improvement with respect to the former from a phenomenological point of view. Finally, in the third chapter I will attempt a phenomenological clarification of Weyl's view. In the first and second chapter Weyl's studies are clarified showing how they are related with the phenomenological framework of Husserl's philosophy. Despite this, the theoretical proposal revealed by them is not so easy to understand. That issue seems to be shared by many other contemporary studies. The relevant literature on this author dealing with a phenomenological interpretation seems often to be hardly understandable. I'm going to outline the main problems involved in this field of research and how they are related with the peculiarity of Husserl's framework. I will then suggest a way to improve these studies. Specifically, I will attempt a phenomenological clarification of Weyl's writings. To this aim, I will argue for an approach that makes use of Husserl's writings as a sort of ``analytic tools'' so that a sort of phenomenologically-informed reconstruction of Weyl's thought can be achieved. I will finally consider Weyl's notion of surface as a case study to show a concrete example of this kind of reconstruction.
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44

Börner, Robert. "Surface reactions of CO with Nickel :a multiple method approach using newly developed concepts." Doctoral thesis, Universite Libre de Bruxelles, 2002. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211457.

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45

Brumbach, Michael T. "Near Surface Composition and Reactivity of Indium Tin Oxide: An Evaluation Towards Surface Chemical Concepts and Relevance in Titanyl Phthalocyanine Photovoltaic Devices." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195338.

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Photovoltaics manufactured using organic materials as a substitute for inorganic materials may provide for cheaper production of solar cells if their efficiencies can be made comparable to existing technologies. Photovoltaic devices are comprised of layered structures where the electrical, chemical, and physical properties at the multiple interfaces play a significant role in the operation of the completed device. This thesis attempts to establish a relationship between interfacial properties and overall device performance by investigation of both the organic/organic heterojunction interface, as well as the interface between the inorganic substrate and the first organic layer with useful insights towards enhancing the efficiency of organic solar cells.It has been proposed that residual chemical species may act as barriers to charge transfer at the interface between the transparent conductor (TCO) and the first organic layer, possibly causing a large contact resistance and leading to reduced device performance. Previous work has investigated the surface of the TCO but no baseline characterization of carbon-free surfaces has previously been given. In this work clean surfaces are investigated to develop a fundamental understanding of the intrinsic spectra such that further analyses of contaminated surfaces can be presented systematically and reproducibly to develop a chemical model of the TCO surface.The energy level offset at the organic/organic heterojunction has been proposed to relate to the maximum potential achievable for a solar cell under illumination, however, few experimental observations have been made where both the interface characterization and device performance are presented. Photovoltaic properties are examined in this work with titanyl phthalocyanine used as a novel donor material for enhancement of spectral absorption and optimization of the open-circuit potential. Characterization of the interface between TiOPc and C60 coupled with characterization of the interface between copper phthalocyanine and C60 shows that the higher ionization potential of TiOPc does correlate to greater open circuit potentials.Examination of photovoltaic behavior using equivalent circuit modeling relates the importance of series resistance and recombination to the homogeneity of the solar cell structure.
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46

Zaloum, Ronald. "Développement et validation d'un concept de surfaces de réponse pour évaluer la traitabilité des effluents." Metz, 1986. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1986/Zaloum.Ronald.SMZ8628.pdf.

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Nous avons développé et validé un concept d'interprétation et d'évaluation de la traitabilité biologique d'effluents par des surfaces de réponse définies en fonction de l'âge de boues, du temps de séjour hydraulique et de la concentration organique (DCO totale) de l'effluent. Ce concept définit des régions ou des segments d'isoréponse selon le paramètre sélectionné. La superposition de régions d'isoréponse permet de choisir les conditions optimales d'opération pour le paramètre d'intérêt le plus restrictif. Le concept de régions d'isoréponse sert d'outil d'optimisation, de gestion de l'opération et de décisions modifiant ou agrandissant la chaîne de traitement dans le but de se conformer aux normes. Il dévoile des limites de l'influence de l'âge de boues comme paramètre de contrôle et fait ressortir l'influence du temps de rétention hydraulique sur la stabilité et le rendement du système ainsi que sur l'évolution de la biomasse et de son comportement. L'analyse de la traitabilité par des surfaces de réponse a mis en évidence d'importantes lacunes dans les modèles traditionnels. Nous montrons l'inaptitude du rapport F/M comme paramètre de conception et d'opération, la quasi-indépendance de l'âge de boues et du temps de séjour hydraulique dans le contrôle du procédé biologique et l'effet des paramètres de contrôle sur la composition microbiologique durant la traitabilité. Cette étude fut réalisée sur des effluents variables d'un abattoir aux échelles pilotes et réelle
It was demonstrated that biological treatment response to changes in SRT, HRT, and influent total COD could be described by response surfaces for each effleunt parameter under investigation. Iso-response regions or lines could be obtained thus defining the ranges of SRT and organic load combinations which must be maintained in order to ensure a given effluent quality. The response surface for the most restrictive parameter will ensure that operating conditions are chosen in such a way as to maximize the performance of the system as a whole. This concept can assist in optimization, upgrading or retrofitting decision making. This study showed that the effect of SRT is significantly reduced beyond a value of 15 days. In addition, HRT has been shown to be equally important to SRT as a process control parameter with significant impact on system stability, sludge setleability and microbial composition, as well as on the performance. Process control can be achieved by modifying jointly or separately each parameter. The inequacy of the F/M ratio as an operating and design parameter was demonstrated experimentally through its lack of predictive potential. Also the usefulness of ATP as a biological performance indicator was assessed. This concept was developped at pilot scale using settled variable abbatoir waste and successfully applied to the operation of the full scale treatment facility receiving the same wastewater
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47

Zaloum, Ronald. "Développement et validation d'un concept de surfaces de réponse pour évaluer la traitabilité des effluents." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37601964b.

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48

Zaloum, Ronald Block Jean-Claude. "Développement et validation d'un concept de surfaces de réponse pour évaluer la traitabilité des effluents." Metz : Université de Metz, 2008. ftp://ftp.scd.univ-metz.fr/pub/Theses/1986/Zaloum.Ronald.SMZ8628.pdf.

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49

Fournier, Pierre. "Frottement sec de matériaux céramiques monolithiques, composites et réfractaires : analyse à partir du concept "3ème corps"." Limoges, 1997. http://www.theses.fr/1997LIMO0030.

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Le frottement sec de differents materiaux ceramiques est analyse par l'approche du <<<>troisieme corps<>>> en considerant les mecanismes d'accommodation de vitesses et l'efficacite du troisieme corps au sein du contact. Une premiere partie concerne le comportement tribologique de couples de ceramiques monolithiques, essentiellement sic, si#3n#4 et al#2o#3, a differentes temperatures. L'etude de l'amelioration du comportement tribologique de ces couples de materiaux par l'utilisation de lubrifiants solides clot cette premiere partie. Une seconde partie porte sur le comportement tribologique de materiaux composites c-sic. Le comportement tribologique de ces materiaux est etudie en considerant les influences de la nature des fibres, des parametres d'elaboration des composites et des conditions mecaniques de frottement. Une derniere partie est consacree au frottement d'une ceramique refractaire sur un materiau metallique. La connaissance des mecanismes d'accommodation de vitesses et de formation du troisieme corps permet d'identifier les parametres fondamentaux (pression et temperature du contact) qui gouvernent l'usure du materiau refractaire.
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Favrat, Jean-François. "Une expérience sur l'enseignement des surfaces a l'école élémentaire." Paris 7, 1986. http://www.theses.fr/1986PA077072.

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La géométrie à l'école élémentaire est surtout consacrée à la maitrise de la latéralisation, au repérage plan, a la reconnaissance des formes planes et leur trace, puis a l'étude des développements de quelques solides. Quels pourraient être des contenus et des démarches pédagogiques pour des apprentissages les concernant. La première aborde les définitions des surfaces. La seconde est un tour d'horizon des outils mis à la disposition des maitres pour construire un enseignement sur les surfaces. Le troisième rend compte d'activités conduites avec les enfants de cours élémentaire deuxième année (8-9 ans)
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