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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biomimicry and the low carbon vehicle : generation of innovative bio-inspired concepts using the C-K theory / Biomimétisme et véhicule décarboné : génération de concepts innovants bio-inspirés à partir de la théorie C-K

Freitas Salgueiredo, Camila 25 October 2016 (has links)
Le biomimétisme ou conception bio-inspirée est une approche qui propose l'utilisation du vivant en tant que source d'inspiration pour améliorer ou concevoir de nouvelles technologies. Intégrer la conception bio-inspirée au processus d'innovation des entreprises pourrait ainsi permettre la génération de concepts à la fois innovants et durables.Cette thèse, réalisée au sein de Renault avait deux objectifs: comprendre les mécanismes de la conception bio-inspirée et les appliquer à un cas concret dans l'automobile pour stimuler la génération de concepts en rupture.Pour comprendre les mécanismes de la bio-inspiration, nous nous sommes appuyés sur la littérature scientifique ainsi que sur les inventions et concepts bio-inspirés. Pour analyser le raisonnement de conception de ces exemples, nous avons choisi une théorie de la conception, la théorie C-K. Le cadre issu de la théorie C-K nous a permis de proposer un modèle général pour la conception bio-inspirée.Nous avons appliqué ce modèle au champ d'innovation du véhicule décarboné. Ce champ traite des questions liées au développement d'innovations permettant aux véhicules de réduire leur empreinte environnementale, principalement par la réduction des émissions de dioxyde de carbone (CO2), un puissant gaz à effet de serre qui contribue également au phénomène du changement climatique. L'identification des voies où la rupture serait nécessaire a débuté par la réalisation d'un arbre des concepts, à l'aide des connaissances internes disponibles en entreprise auprès des experts leaders. Un travail de réorganisation de ces concepts et la création d'une base de connaissances rassemblant articles scientifiques et expertises sur le sujet des émissions de gaz à effet de serre ont été effectués. Ce travail a permis de cartographier le champ d'innovation du véhicule décarboné. Les véhicules multi-énergies ont été la voie choisie pour la recherche de concepts bio-inspirés.Une recherche générale sur l'énergie dans le vivant nous a conduits à identifier l'énergie dans les cellules animales et particulièrement chez les humains comme une base de connaissances biologiques particulièrement intéressante. L'énergétique humaine possède un certain nombre de propriétés qui pourraient permettre une révision des connaissances sur les véhicules multi-énergie, notamment sur le stockage et la transformation d’énergie. La performance sportive humaine s'est aussi révélée être une base de connaissances intéressante par les différentes techniques utilisées pour les entrainements et en course afin de mieux mobiliser des sources d'énergie.L'application du modèle du processus de bio-inspiration avec C-K nous a conduit à formuler un concept inspiré des observations réalisées sur des coureurs pendant des courses supérieures à 1 500m. En effet, les profils de vitesse enregistrés pour des athlètes indiquent qu'une variation de vitesse est choisie par le coureur pour lui permettre de mieux utiliser ses réserves anaérobies limitées. Pour un véhicule, ceci pourrait impliquer qu'une variation de vitesse pourrait conduire à des meilleurs résultats en termes de consommation de carburant qu'une vitesse stabilisée. Ce concept a été exploré dans cette thèse à l’aide de la réalisation d'essais sur piste et des simulations avec des modèles numériques. Ces explorations montrent le potentiel de ce concept pour des véhicules conventionnels et aussi ses limitations.Ces travaux ouvrent des perspectives pour la gestion d'énergie des véhicules considérant la façon dont l'énergie est produite, stockée et utilisée chez le vivant. Les systèmes énergétiques étudiés par la physiologie humaine représentent un terrain intéressant pour le développement de véhicules adaptables à différents cas d'utilisation. De plus, l'étude du processus de la bio-inspiration a permis d'éclairer les raisons de faire appel à cette démarche et les conditions qui permettraient son application plus systématique dans les processus d'innovation en entreprise. / Biologically inspired design, also called bioinspired design, biomimetics or biomimicryproposes the use of Nature, or biological knowledge, as a source of inspiration to improve orconceive new designs. Integrating the biologically inspired design approach into theinnovation process of companies could then allow the generation of more innovative and sustainable concepts.This thesis, realized during three years at a French automaker (Renault) research and development department had two objectives: to understand the mechanisms of the biologically inspired design and to apply this approach to a case belonging to an innovation field of the automotive sector.In order to understand the mechanisms of biologically inspired design we studied theliterature about bio-inspired concepts and inventions.We have chosen a design theory, the C-K theory, to analyse the design process of these literature examples. This allowed us to propose a model for bio-inspiration.We applied this model inspired by the C-K theory to the low carbon vehicle innovation field.This field includes the development of innovations allowing passenger cars to reduce theirenvironmental footprint, mainly the reduction of carbon dioxide (CO2) emissions. Thecarbon dioxide is a greenhouse gas that contributes to the climate change phenomena. Theidentification of the path where concept partitioning is required in this field began with theconstruction of a concepts space, using knowledge of company experts on the subject.Reorganizing these concepts and building a knowledge base on the strategies for CO2 emissions allowed us to map this innovation field. The vehicles with more than oneenergy source, such as electrified internal combustion engine vehicles and hybrid vehicleswere the path chosen for the research of bio-inspired concepts.A research about energy in nature led us to identify the energy in animal cells, particularlythose in humans as an interesting biological knowledge base. Human energy properties suchas cells with more than one kind of energy storage, with at least two metabolic pathways torecharge these stores are interesting to revise the knowledge about energy store andconversion in multi-energy vehicles. Besides, the human sportive performance has appearedto be an interesting knowledge base, as the training techniques and the running techniquesduring a race can influence the way athletes use their energy.These two biological bases have led us to formulate a bio-inspired concept based on therunning patterns observed in runners during races superior to 1500~m. The speed profilesrecorded show a spontaneous speed variation chosen by the runner, in order to better use itslimited anaerobic energy stores. For a vehicle, this could mean that varying its speed couldallow a lower fuel consumption than using a constant speed. This bio-inspired concept wasexplored in this thesis with the realization of tests in a dedicated test track and simulations. These tests show the potential of this concept for conventional vehicles and its limitations.This work opens the way for analysing the vehicle energetics in the light of human energetics.The versatility of human activities could help on the development of vehicles adapting todifferent use cases. Further research could also use the knowledge about the dynamic modelling of energy in vehicles to complete the empirical approaches used to model the human energy management, allowing a betteroptimization of running strategies. The study of the bio-inspiration process using a designtheory also allowed a better comprehension of the reasons for using this approach and of theconditions for successfully applying it in the innovative process of a company.
2

Distribuição de tensões e probabilidade de falha de coroas totais em zircônia tradicional, graduada e bioinspirada / Stress distribution and failure probability of all ceramic crowns in traditional, graded and bioinspired zirconia

Ramos, Gabriela Freitas 08 June 2018 (has links)
Submitted by Gabriela Freitas Ramos (gabrieladsfreitas@gmail.com) on 2018-08-08T01:12:25Z No. of bitstreams: 1 Gabriela F R.pdf: 2402001 bytes, checksum: 25f255b66f5d6d03803d8caedbfb8205 (MD5) / Approved for entry into archive by Silvana Alvarez null (silvana@ict.unesp.br) on 2018-08-16T15:30:22Z (GMT) No. of bitstreams: 1 Gabriela F R.pdf: 2402001 bytes, checksum: 25f255b66f5d6d03803d8caedbfb8205 (MD5) / Made available in DSpace on 2018-08-16T15:30:22Z (GMT). No. of bitstreams: 1 Gabriela F R.pdf: 2402001 bytes, checksum: 25f255b66f5d6d03803d8caedbfb8205 (MD5) Previous issue date: 2018-06-08 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O objetivo foi avaliar a probabilidade de falha de coroas de zircônia-porcelana com e sem infiltração de sílica (gradação) da zircônia, em disposição tradicional, graduada e bioinspirada, através da análise de Weibull e de elementos finitos pelo critério de Tensão Máxima Principal. Foram utilizados cem preparos anatômicos de primeiro molar superior (26) confeccionados em resina epóxi- Nema G10, que foram divididos em quatro grupos: Tradicional: infraestrutura em zircônia (Zircônia Convencional-Incoris ZI, Sirona, Brasil) e cobertura de porcelana (Cerâmica Feldspática-Cerec Blocs); Graduada: infraestrutura em zircônia infiltrada por sílica e cobertura de porcelana; Bioinspirada: infraestrutura em porcelana e cobertura com zircônia (Zircônia translúcida-Incoris TZI, Sirona, Brasil); e Bioinspirada Graduada: infraestrutura em porcelana e cobertura com zircônia infiltrada por sílica. A porção mais externa de todas as coroas foi revestida com uma camada glaze. A carga para fadiga deslizante foi de 100 N. Então os espécimes foram ciclados mecanicamente em um simulador de ciclos mastigatórios no qual uma ponta aplicadora fez 2.106 ciclos a uma frequência de 4 Hz. A cada 500.000 ciclos as coroas foram avaliadas quanto à presença de falhas (trincas, lascamentos ou descolamento entre porcelana e zircônia, fraturas catastróficas), em estereomicroscópio. Os tipos de falhas predominantes para as coroas Tradicional e Graduada foram delaminação e trincas, respectivamente. Os parâmetros de Weibull (beta e eta), com intervalo de confiança bilateral de 95% foram respectivamente: Tradicional - 1,29 e 0,23 E+07 ciclos; Graduada - 1,95 e 0,23 E+07 ciclos; Bioinspirada - 1,00 e 1,67 E+07 ciclos e Bioinspirada graduada - 1,00 1,67 E+07 ciclos. As coroas Tradicionais e Graduadas apresentaram maior susceptibilidade à falha por fadiga e as Bioinspiradas e Bioinspiradas graduadas não demonstraram susceptibilidade à fadiga. Ainda, através da Análise de elementos finitos, pôde-se verificar que as coroas bioinspiradas e bioinspiradas graduadas apresentaram a melhor distribuição de tensões tanto sobre a coroa quanto para a estrutura dentária. As diferentes configurações de restauração apresentaram diferentes probabilidades de falha após o ensaio de fadiga deslizante, sendo que as coroas Bioinspirada e Bioinspirada Graduada apresentam a menor probabilidade de falha e melhor distribuição de tensões, podendo ser consideradas restaurações mais duradouras em longo prazo. / The objective was to evaluate the failure probability of zirconia-porcelain crowns with and without silica infiltration (graded material) of the zirconia, using traditional, graded and bio-inspired design, through Weibull and finite element analysis by maximum principal stress. One hundred anatomical preparations of first upper molar were made of epoxy resin Nema G10 and divided into four groups: Traditional- zirconia (Conventional zirconia -Incoris ZI, Sirona, Brazil) and porcelain cover (Feldsphatic ceramic-Cerec Blocks); Graded- infrastructure in zirconia silica infiltrated and porcelain cover; Bioinspired- porcelain infrastructure and zirconia cover (Trasnlucent zirconia-Incoris TZI, Sirona, Brazil); and Graded Bioinspired- porcelain infrastructure and zirconia infiltrated by silica cover. The outermost portion of all crowns was coated with a glaze layer. The load for sliding fatigue was 100 N. Then the specimens were mechanically cycled in a masticatory cycle simulator for 2 x 106 cycles at 4 Hz of frequency. Every 500k cycles the crowns were evaluated in stereomicroscope for failures presence (cracks, chipping or detachment between porcelain and zirconia, or catastrophic fractures). The predominant failure types for the Traditional and Graded crowns were delamination and cracking, respectively. The Weibull parameters (beta and eta) with 95% bilateral confidence interval were respectively: Traditional - 1.29 and 0.23 E + 07 cycles; Graded - 1.95 and 0.23 E + 07 cycles; Bioinspired - 1,00 and 1,67 E + 07 cycles and Graded Bioinspired - 1,00 1,67 E + 07 cycles. The Traditional and Graded crowns presented greater susceptibility to failure due to fatigue and the Bioinspired and Graded Bioinspired crowns showed no susceptibility to fatigue. Also, through the finite elements analysis, it was verified that the Bioinspired and Graded Bioinspired crowns presented the best stress distribution on both crown and dental structure. The different restoration configurations presented different failure probabilities after the sliding fatigue test. Bioinspired and Graded Bioinspired crowns had the lowest failure probability and better stress distribution, which may be considered lasting restorations in the long term. / 2015/110013
3

Location Finding in Natural Environments with Biomimetic Sonar and Deep Learning

Zhang, Liujun 24 October 2022 (has links)
Bats are famous for their capability of navigating in dense forests for hundreds of kilometers within one night by using their sonar system. Airborne sonar hasn't been heavily used in the industrial world compared to other sensors such as lidar, radar, and cameras. In this study, we applied a biosonar robot to navigate in a dense forest with bat-like FM-CF ultrasonic signals with deep learning. The results presented show that airborne biosonar can classify different areas' plants, in addition to achieving a similar level of navigation granularity compared to GPS, which is about 6 meters of radius resolution. The time- frequency representations of echoes from the forest are used as input data to explore the biosonar navigation ability, and the state-of-the-art CNN deep network (Resnet 152) is used as the brain to do the echolocation in the dense forest. The navigation ability can be improved significantly by combining multiple 10 ms long echoes, however, the data size of the reflected waves is much smaller than the other popularly used sensors, as echo can be collected at a rate of 40 echoes per second. The results can prove that airborne sonar can be used to navigate in GPS-denied environments, and can be an important sensor used in a scenario when other sensors meet constraints, like in the sensor fusion applications. / Doctor of Philosophy / The ability to identify natural landmarks could contribute to the navigation skills of echolo- cating bats and also advance the quest for autonomy in natural environments with man- made systems. The critical sensors used in autonomous robot navigation are camera array, radar, and lidar, airborne sonar hasn't been verified for its navigation efficiency. However, recognizing natural landmarks based on biosonar echoes has to deal with the unpredictable nature of echoes that are typically superpositions of contributions from many different reflec- tors with unknown properties. This dissertation intends to explore the bioinspired airborne sonar navigation ability in dense natural forests. The first part of this project is to use reflected echoes to navigate on a large scale, data was collected from different mountains which are dozens of kilometers away from each other, and we achieved the use of one single navigator in those locations. The second part is to explore the navigation granularity of airborne sonar sensors, data were collected from a small dense forest area, we try to classify which part of the foliage was based on the echo, and in the end, we achieved GPS accuracy for navigation. The finding in this work proves that the sonar sensor can play an important role in the sensing system, with the help of a deep neural network, with a 10 ms long echo, it can have a similar navigation ability to GPS.
4

Force Measurement of Basilisk Lizard Running on Water

January 2019 (has links)
abstract: Basilisk lizards are often studied for their unique ability to run across the surface of water. Due to the complicated fluid dynamics of this process, the forces applied on the water’s surface cannot be measured using traditional methods. This thesis presents a novel technique of measuring the forces using a fluid dynamic force platform (FDFP), a light, rigid box immersed in water. This platform, along with a motion capture system, can be used to characterize the kinematics and dynamics of a basilisk lizard running on water. This could ultimately lead to robots that can run on water in a similar manner. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2019
5

Chitin nanofibers, networks and composites : Preparation, structure and mechanical properties

Mushi, Ngesa Ezekiel January 2014 (has links)
Chitin is an important reinforcing component in load-bearing structures in many organisms such as insects and crustaceans (i.e. shrimps, lobsters, crabs etc.). It is of increasing interest for use in packaging materials as well as in biomedical applications. Furthermore, biological materials may inspire the development of new man-made material concepts. Chitinmolecules are crystallized in extended chain conformations to form nanoscale fibrils of about 3 nm in diameter. In the present study, novel materialshave been developed based on a new type of chitin nanofibers prepared from the lobster exoskeleton. Improved understanding about effects of chitin from crustaceans and chitin material preparation on structure is provided through Atomic Force Microscopy(AFM) (paper I&amp;II), Scanning Transmission Electron Microscopy(STEM) (paper I&amp;II), X-Ray Diffraction (XRD), Intrinsic Viscosity, solid state 13C Nuclear Magnetic Resonance (NMR) (paper II), Field Emission Scanning Electron Microscopy(FE-SEM) (paper I, II, III, IV &amp; V), Ultraviolet-Visible Spectrophotometryand Dynamic Light Scattering (DLS) (paper III). The presence of protein was confirmed through colorimetric method(paper I &amp; II). An interesting result from the thesis is the new features of chitin nanofiber including small diameter, high molar mass or nanofiber length,and high purity. The structure and composition of the nanofibers confirms this (paper I &amp; II). Furthermore, the structure and properties of the corresponding materials confirm the uniqueness of the present nanofibers: chitin membrane (I &amp; II), polymer matrix composites (III),and hydrogels (paper IV). Improved mechanical properties compared with typical data from the literature were confirmed for chitin nanofiber membranes in paper II, chitin-chitosan polymer matrix composites in paper III, and chitin hydrogel in paper IV. Mechanical tests included dynamic mechanical analysis and uniaxial tensile tests. Mechanical properties of chitin hydrogels were evaluated based onrheological and compression properties (paper IV). The values were the highest reported for this kind of chitin material. Furthermore, the relationships between materials structure and properties were analyzed. For membranes and polymer matrix nanocomposites, the degree of dispersion is an important parameter. For the hydrogels, the preparation procedure is very simple and has interesting practical potential. Chitin-binding characteristics of cuticular proteins areinteresting fornovel bio-inspired material development. In the present work(paper V), chitin nanofibers with newfeaturesincluding high surface area and low protein content were combined with resilin-like protein possessing the chitin-binding characteristics. Hydrated chitin-resilin nanocomposites with similar composition as in rubber-like insect cuticles were prepared. The main objective was to improve understanding on the role of chitin-binding domain on mechanical properties. Resilin is a rubber-like protein present in insects. The exon I (comprising 18 N-terminal elastic repeat units) together with or without the exon II (a typical cuticular chitin-binding domain) from the resilin gene CG15920 found in Drosophila melanogasterwere cloned and the encoded proteins were expressed as soluble products in Escherichia coli.Resilin-like protein with chitin-binding domain (designated as ResChBD) adsorbedin significant amount to chitin nanofiber surface andprotein-bound cuticle-like soft nanocomposites were formed. Although chitin bindingwas taking place only in proteinswith chitin-binding domain, the global mechanical behavior of the hydrated chitin-resilin nanocomposites was not so sensitive to this chitin-resilin interaction. In summary, chitin is an interesting material component with high potential as mechanical reinforcement in a variety of nanomaterials. The present study reports the genesisof novel chitin nanofibers and outlines the basic relationships between structure and properties for materials based on chitin. Future work should be directed towards both bio-inspired studies of the nanocomposite chitin structures in organisms, as well as the industrial applications of chitin waste from the food industry. Chitin nanofibers can strengthen the properties of materials, andprovide optical transparency as well as biological activities such as antimicrobial properties. / <p>QC 20141110</p>
6

Tree-Inspired Water Harvesting

Shi, Weiwei 13 April 2020 (has links)
In this work, we were motivated to develop novel devices for water harvesting inspired by natural trees, and to understand their collection efficiency and working principles. We accomplished that with scale-model and large-scale fog harps, floating leaves, and synthetic trees. Fluids mechanics, physics, and thermodynamics were applied to solve the problems and rationalize the results. Redwood-inspired fog harps were designed with stainless steel vertical wires, using 3D-printing and laser-cutting techniques. Fog harps always harvested more water than any of the meshes, tested both under heavy fog and light fog conditions. The aerodynamic efficiency, deposition efficiency, and sliding efficiency were calculated to compare the fog harvesting performance. These findings provide insight into the new design of fog harvesters with high-efficiency fog harvesting performance, and future development of large fog harps, applied into regions even with light fog conditions, as an economically viable means. synthetic trees were fabricated with a nanoporous ceramic disk and silicone tubes. This tree system was tested in an environmental chamber (6 cm short trees) or a plant growth chamber (3m tall trees), both with controlled ambient humidities. The system pressure was calculated with Darcy's equation, Poiseuille equation and Laplace equation. The stable transpiration can happen to any scalable tree, which pumps water up an array of large tubes. Our synthetic trees, like natural trees, have the ability to lift water across a wide range of water temperatures and ambient humidities. They can be used as the large-scale evaporation-driven hydraulic pump, for example, pumped storage hydropower, filtration, underground water extraction. / Doctor of Philosophy / The purpose of this work is to investigate and characterize novel techniques for water harvesting that are inspired by natural trees. We are interested in two modes of water harvesting in particular: fog harps and synthetic trees. Fog harps were comprised of only vertical wires, inspired by the parallel structures of redwoods, which can capture and shed off fog droplets efficiently. Fog harps harvested more water than the traditional mesh nets, both under heavy fog and light fog conditions. Redwood-inspired fog harps have the high-efficient fog harvesting performance. They can be set up at coastal deserts to collect water from fog, where there is scarce rainfall but plenty of fog, like Chile, Peru and South Africa. Synthetic trees were designed with nanoporous disk (leaf) and tubes (xylem conduits), inspired by the transpiration process in natural trees. This transpiration-powered pump can lift water against the gravity at large scales, driven by the water evaporating from the nanopores. They can be used as the large-scale evaporation-driven hydraulic pump, for example, pumped storage hydropower, filtration, underground water extraction.
7

Prototypage d'un objet volant mimant l'insecte / Prototyping of a Nano air vehicle mimicking flying insect

Bontemps, Alexandre 09 December 2013 (has links)
Ce travail de thèse s'inscrit dans le contexte des drones vise à réaliser à terme un Nano-dispositif volant (Nano Aerial Vehicle) capable d'imiter le vol des insectes. Ce mode de locomotion est privilégié car il présente des caractéristiques très adaptées au vol en milieu confiné. La solution proposée consiste à développer un drone de la taille d'un insecte s'appuyant sur des ailes vibrantes pour se mouvoir et à utiliser les technologies MEMS pour répondre aux problématiques de fabrication et de réduction d'échelle. La réussite d'un tel projet soulève néanmoins de nombreux défis scientifiques et technologiques, en particulier, les aspects aéro-élastiques des ailes et l'autonomie du drone. Pour répondre à ces défis, nous proposons dans un premier temps de mettre en œuvre des concepts comme la résonance et la torsion passive sur des prototypes en polymère (SU-8) réalisés par photolithographie. Dans un second temps, les différents composants de la chaîne de puissance sont optimisés, notamment l'actionneur électromagnétique, la liaison et les ailes de manière à maximiser la force de portance générée. Suite à ces améliorations, nous démontrons de façon expérimentale que le prototype était capable non seulement de reproduire une cinématique complexe mais également de compenser 75% de son poids. / This manuscript reports a work which aims to develop a tiny flying robots inspired by natural flyers. Our main objective is to devise a flying robot mimicking insects in terms of kinematics and scale using MEMS technologies in order to answer the scale challenges: the large-scale manufacturing and the system's small scale. The success this project faces different challenges such as aeroelastic aspects of wings and drone autonomy.In this work we propose the use of original concepts like resonance and passive torsion of the wings which are implemented on all-polymer prototypes obtained using a micromachining SU-8 photoresist process. In order to achieve a better efficiency of the prototype, each element of the energy transduction has been carefully examined and optimized. Especially, the actuation, the transmission and the wings in order to increase the lift. These improvements demonstrate experimentally that the prototype is able to produce a complex kinematic and compensate 75 % of its weight.
8

Conception et synthèse bioinspirées de nucléolipides pour l'élaboration de biomatériaux / Bioinspired design and synthesis of nucleolipids for biomaterials conception

Hamoud, Aladin 06 December 2018 (has links)
Les nucléolipides sont des molécules hybrides amphiphiles de faible poids moléculaire composées de deux parties liées de façon covalente : la première est un acide nucléique, un nucléotide, un nucléoside ou une nucléobase et la seconde un lipide. En combinant les propriétés physicochimiques de deux des biomolécules parmi les plus représentées dans le vivant, les nucléolipides présentent la capacité à former des auto-assemblages supramoléculaires d’intérêt pour la conception de biomatériaux. L'étude des capacités d’auto-assemblage des GlycoNucléoLipides, qui possèdent un lien aromatique de type triazole, a démontré que la nature du lien covalent qui unit les deux parties du nucléolipide a un effet déterminant sur l’assemblage. Ce travail a porté sur l'utilisation et le développement d'une réaction de Stetter, organocatalysée par des carbènes N-hétérocycliques et bioinspirée, pour obtenir un lien de type dicétone-1,4 entre la thymidine et différents lipides. Ce motif, précurseur de cycles hétéroaromatiques, a notamment conduit à la formation de liens de type pyrrole par une réaction de type Paal-Knorr. Les propriétés gélatrices de ces nucléolipides originaux ont été comparées à celles de ceux portant un motif triazole. Parmi les nucléolipides obtenus, un composé particulièrement lipophile, porteur du lien 1,4- dicétone, a montré la capacité de former un gel dans des huiles (soit un oléogel). Une étude structurepropriétés a été effectuée pour comprendre le rôle de chaque partie de la molécule. Ce type de formulation présentant un intérêt tout particulier pour le développement de systèmes de délivrance contrôlée de substances actives lipophiles, les propriétés physicochimiques de cet oléogel ont par ailleurs été étudiées. La réaction de Stetter présentant la plupart des caractéristiques d'une réaction dite de "chimie click", des conditions de réaction plus éco-compatibles et adaptées à la fonctionnalisation d’autres biomolécules ont ensuite été développées en milieu aqueux. / Nucleolipids are hybrid amphiphilic low molecular weight molecules composed of two parts covalently linked: the first one being a nucleic acid, a nucleotide, a nucleoside or a nucleobase and the second a lipid. Combining the physico-chemical properties of two of the most widespread biomolecules, nucleolipids are capable of self-assemble as supramolecular structures of interest for application in the field of biomaterials. The study of the self-assembling properties of GlycoNucleoLipids, bearing a triazole moiety as a linker, demonstrated the crucial influence of the nature of the covalent linker bringing together the two parts of the nucleolipid onto the self-assembly. In this work, the synthesis of nucleolipids bearing a 1,4-diketone linker between thymidine and various lipids via the bioinspired and N-Heterocyclic Carbene organocatalyzed Stetter reaction is described. As an heteroaromatic cycle precursor, this moiety led to the formation of pyrrole skeletons via the classical Paal-Knorr reaction. The gelating properties of these original nucleolipids were evaluated and compared with the ones bearing a triazole link. Among these original synthetic nucleolipids, a lipophilic compound bearing a 1,4-diketone link exhibited the ability to form gels in oils (i.e. oleogels). A structure-properties study was realized to understand the role of each part of the molecule. This type of formulation being of particular interest for the development of lipophilic drug delivery systems, the physico-chemical properties of the oleogel were also extensively studied. The Stetter reaction exhibiting most of the « click chemistry » characteristics, eco-friendly reaction conditions were developed in aqueous media and applied to other biomolecules conjugation.
9

Couplage modal pour la reproduction de la cinématique d'une aile d'insecte et la génération de portance d'un nano-drone bio-inspiré / Modes coupling to reproduce insect wing kinematics and generate lift with a bio inspired nano-air vehicle

Faux, Damien 19 February 2018 (has links)
Cette recherche dans le domaine des nano-drones a pour ambition de concevoir un objet volant de taille réduite s’inspirant directement de la nature.Dans ce but, un état de l’art a été fait sur les mécanismes de vol des insectes ainsi que sur l’ensemble des solutions à ailes battantes artificielles développées à ce jour. Il ressort de cette analyse d’une part, que les insectes ont une cinématique des ailes singulière reposant sur un mouvement de battement et de torsion en quadrature de phase et d’autre part, que les nano-drones actuels ne s’appuient pas ou très peu sur le comportement dynamique de leurs ailes artificielles pour générer de la portance. Le concept proposé dans le cadre de ce travail se veut en rupture avec ces approches. Il consiste en un couplage vibratoire en quadrature de phase de modes de battement et de torsion appliqué sur des ailes artificielles flexibles afin de reproduire une cinématique proche de celles des insectes avec un unique actionneur. La méthodologie employée s’est traduite par l’élaboration d’un modèle analytique négligeant les efforts aérodynamiques afin de calculer le comportement dynamique et de dimensionner la structure du nano-drone. Les simulations ont mis en évidence l’existence de modes propres de la structure des ailes dont les déformées correspondent aux mouvements de battement et de torsion recherchés. Fait remarquable, une optimisation a permis de rapprocher les fréquences de ces modes tout en conservant une amplitude suffisante de façon à réaliser leur couplage et donc à reproduire la cinématique souhaitée. La portance produite a été ensuite estimée à l’aide d’un modèle aéroélastique qui a montré que le maximum de portance était obtenu pour deux fréquences coïncidant avec une quadrature de phase entre les deux modes. Ces résultats ont par la suite été confirmés à l’aide de mesures expérimentales effectuées sur un banc de mesure spécifique répondant aux contraintes imposées par les prototypes en termes de sensibilité et de comportement dynamique. Les différentes générations de prototypes testées ont été fabriquées au moyen des procédés de microfabrication, ce qui a permis l’intégration d’une membrane d’aile en parylène d’une épaisseur tout à fait comparable à celle existant chez les insectes. La conclusion de cette étude est que nous disposons dorénavant d’un prototype capable de compenser son poids. / This work in the Nano-Air Vehicle field aims to design a small flying object directly inspired by the nature. For this purpose, a state of the art has been performed on insects flight mecanisms and has reviewed the overall artificial flapping wings solutions developped until today. The result of this analysis is on one hand, that insects use a specific wing kinematics which relies on a flapping motion and a twisting motion coupled in a quadrature phase shift and on the other hand, that the existing Nano-Air Vehicles do not exploit the dynamic behavior of their artificial wings to produce lift. The proposed concept in this research is a departure from those other works. It consists of a vibratory coupling in a quadrature phase shift of a flapping and a twisting mode applied on flexible artificial wings in order to reproduce a kinematics close to the insects ones with a single actuator. The used methodology resulted in the development of an analytic modeling which neglects the aerodynamic forces to calculate the dynamic behavior and dimension the prototype structure. Simulations highlighted the existence of eigen modes of the wings structure whose modal shapes match with the wanted flapping and twisting motion. Noteworthy fact, an optimization allowed to get those modes close in frequency while keeping a non-neglectible amplitude in such a way as to couple them and obtain the expected kinematics. The produced lift force is then estimated with an aeroelastic modeling which has shown that the maximum lift is obtained for two frequencies which provide a quadrature phase shift between the two modes. Those results are then validated by experimental measurements performed on a specific bench made according to the constraints due to the prototype in terms of sensitivity and dynamic behavior. The different generations of prototypes tested are produced with microfabrication process, allowing to integrate a wing membrane in parylene with a thickness comparable to the one existing in insects. The conclusion of this study is that we now have a prototype able to compensate its weight.
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Creative eco-effectiveness

Rios Velasco Urrutia, Clara Cecilia 22 November 2010 (has links)
My research is focused upon what industrial designers can contribute in order to mitigate environmental problems often caused by their designs. The intent is to propose a procedure to integrate eco-effectiveness at the beginning of the design process, to consider it at each stage of the product’s lifecycle, and to measure that product’s environmental performance in order to make informed design decisions. At each stage the designer can follow this flexible process, which is intended to work in conjunction with individual creative methods while prioritizing the need for eco-effectiveness. The goal is to develop a procedure that is simple enough for designers to use every day and that could also provide means of verification, rather than relying on assumptions and good intentions. I acknowledge that efforts from a single discipline are not enough. In order to address the environmental challenges we face today, collaboration among disciplines will be necessary, as well as a change of behavior and attitudes towards consumption. This is my contribution. / text

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