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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.
111

Os efeitos sistêmicos de uma reestruturação produtiva: o caso da Lupatech-CSL

Haach, Leandro Francisco January 2010 (has links)
Submitted by Marcia Bacha (marcia.bacha@fgv.br) on 2013-10-24T13:16:59Z No. of bitstreams: 1 Dissertação FGV - Leandro Haach - 2010.pdf: 5449138 bytes, checksum: 58cfd6b86439086caf6e5fb770cebbe2 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2013-10-24T13:17:16Z (GMT) No. of bitstreams: 1 Dissertação FGV - Leandro Haach - 2010.pdf: 5449138 bytes, checksum: 58cfd6b86439086caf6e5fb770cebbe2 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2013-10-24T13:17:32Z (GMT) No. of bitstreams: 1 Dissertação FGV - Leandro Haach - 2010.pdf: 5449138 bytes, checksum: 58cfd6b86439086caf6e5fb770cebbe2 (MD5) / Made available in DSpace on 2013-10-24T13:17:40Z (GMT). No. of bitstreams: 1 Dissertação FGV - Leandro Haach - 2010.pdf: 5449138 bytes, checksum: 58cfd6b86439086caf6e5fb770cebbe2 (MD5) Previous issue date: 2010 / A presente dissertação tem como objetivo estudar o caso da empresa Lupatech CSL no que se refere, fundamentalmente, ao seu processo produtivo. Busca-se também discutir a possibilidade de se promoverem melhorias e mudanças que possam oferecer saídas que oportunizem, através de uma reestruturação produtiva, diferenciações competitivas ao negócio da empresa. Nesse sentido, considerando a análise sistêmica do ambiente, propõe-se a adoção de alguns princípios de gestão do M odelo Toyota de Produção, cujo um dos princípios preconiza uma relação de efetiva parceria com os fornecedores. Para tanto, considerando a permanente necessidade de as empresas buscarem seu equilíbrio e distinção no mercado, procurou-se fazer uma análise do pensamento sistêmico e outras fundamentações de convergência teórica com este trabalho. Além disso, a fim de melhor entender os prós e contras do pensamento toyotista de administração, buscou-se traçar uma investigação desde o antecessor modelo de produção em massa taylorista-fordista até os últimos acontecimentos que abalaram mundialmente a imagem da montadora Toyota. Acredita-se, ao final, que a análise dissertativa do caso da Lupatech poderá fortalecer e auxiliar a empresa em sua tomada de decisão, tanto no campo operacional como na definição de uma proposta estratégica de gestão. / The purpose ofthis dissertation is to study the case ofthe company called Lupatech CSL in matters fundamentally concerning its productive process. The text also discusses the possibility to promote improvements and changes able to provide solutions that will enable competitive differentiation to the company's business through the restructuring of the manufacturing process. Taking into account the systemic analysis of the environment, the paper thus suggests the adoption ofsome principles ofthe Toyota Production M odel, one of which recommends a relationship of effective cooperation and partnership with suppliers. Considering the companies permanent need to seek their equilibrium and distinction in the market, this work tries to establish and analysis of systemic thinking and of other foundations of theoretical convergence. The better grasp the pros and cons of the Toyota¬style management, this dissertation tries to carry out an investigation starting from the early Taylor-Ford mass production model up to the latest events that shook the image ofToyota worldwide. The dissertational analysis ofthe Lupatech case is likely to ultimately strengthen and assist the company in its decision making both in the operational area and in the definition ofstrategic proposition.
112

Multi-Criteria Decision Support for Manufacturing Process Chains

Reichel, Thomas, Rünger, Gudula 28 March 2013 (has links) (PDF)
During the manufacturing planning, multiple variants of process chains for the manufacturing of a product to be developed are generated by engineers. In order to select an optimal variant, multiple decision criteria specifying technical, ecological and economical properties of the process chains as well as multiple assessments of different domain experts have to be taken into account. The contribution of this article is a two-step approach that provides a multi-criteria multi-expert assessment of manufacturing process chains supporting the selection of an optimal process chain. A web-based software tool that implements the multi-criteria assessment of process chains is also presented.
113

Conception et procédés de fabrication avancés pour l’électronique ultra-basse consommation en technologie CMOS 80 nm avec mémoire non volatile embarquée / Design and advanced manufacturing processes for ultra low-power electronic in CMOS 80 nm technology with embedded non-volatile memory

Innocenti, Jordan 10 December 2015 (has links)
L’accroissement du champ d’application et de la performance des microcontrôleurs s’accompagne d’une augmentation de la puissance consommée limitant l’autonomie des systèmes nomades (smartphones, tablettes, ordinateurs portables, implants biomédicaux, …). L’étude menée dans le cadre de la thèse, consiste à réduire la consommation dynamique des circuits fabriqués en technologie CMOS 80 nm avec mémoire non-volatile embarquée (e-NVM) ; à travers l’amélioration des performances des transistors MOS. Pour augmenter la mobilité des porteurs de charge, des techniques de fabrication utilisées dans les nœuds les plus avancés (40 nm, 32 nm) sont d’abord étudiées en fonction de différents critères (intégration, coût, gain en courant/performance). Celles sélectionnées sont ensuite optimisées et adaptées pour être embarquées sur une plate-forme e-NVM 80 nm. L’étape suivante est d’étudier comment transformer le gain en courant, en gain sur la consommation dynamique, sans dégrader la consommation statique. Les approches utilisées ont été de réduire la tension d’alimentation et la largeur des transistors. Un gain en consommation dynamique supérieur à 20 % est démontré sur des oscillateurs en anneau et sur un circuit numérique conçu avec près de 20 000 cellules logiques. La méthodologie appliquée sur le circuit a permis de réduire automatiquement la taille des transistors (évitant ainsi une étape de conception supplémentaire). Enfin, une dernière étude consiste à optimiser la consommation, les performances et la surface des cellules logiques à travers des améliorations de conception et une solution permettant de réduire l’impact de la contrainte induite par l’oxyde STI. / The increase of the scope of application and the performance of microcontrollers is accompanied by an increase in power consumption reducing the life-time of mobile systems (smartphones, tablets, laptops, biomedical implants, …). Here, the work consists of reducing the dynamic consumption of circuits manufactured in embedded non-volatile memories (e-NVM) CMOS 80 nm technology by improving the performance of MOS transistors. In order to increase the carriers’ mobility, manufacturing techniques used in the most advanced technological nodes (40 nm, 32 nm) are firstly studied according to different criteria (process integration, cost, current/performance gain). Then, selected techniques are optimized and adapted to be used on an e-NVM technological platform. The next step is to study how to transform the current gain into dynamic power gain without impacting the static consumption. To do so, the supply voltage and the transistor widths are reduced. Up to 20 % in dynamic current gain is demonstrated using ring oscillators and a digital circuit designed with 20,000 standard cells. The methodology applied on the circuit allows automatic reduction to all transistor widths without additional design modifications. Finally, a last study is performed in order to optimize the consumption, the performance and the area of digital standard cells through design improvements and by reducing the mechanical stress of STI oxide.
114

Ingénierie de la chaîne numérique d'industrialisation : proposition d'un modèle d'interopérabilité pour la conception-fabrication intégrées / Toward a bidirectional and continuous digital chain from CAD to CNC machine : aeronautical industry application

Danjou, Christophe 03 December 2015 (has links)
Ce travail s'intéresse à la gestion d'information techniques et connaissances métiers issues de la production pour assurer l'interopérabilité et la continuité de la chaîne numérique. Dans un contexte d'entreprise étendue et de développement des technologies de l’information pour l'usine du futur, l'industrie aéronautique s'oriente vers une intégration flexible et agile des phases de conception et fabrication pour l'obtention de pièces bonnes du premier coup. C'est pour assurer la maîtrise des processus et la capitalisation des savoir-faire métier issus de la fabrication que ces travaux adressent la problématique suivante : comment élaborer un modèle d'interopérabilité de la chaîne numérique d'industrialisation, pour assurer une intégration agile de la conception et de la fabrication ? Pour ce faire, nous définissons deux propositions : OntoSTEP-NC pour permettre l'extraction et la structuration des données issues de la fabrication et Closed-Loop Manufacturing pour permettre l'intégration et la réutilisation des connaissances métiers capitalisées au niveau de l'industrialisation. Les apports de ces propositions se retrouvent dans la définition d'un cadre d'interopérabilité pour l'usine du futur mais également dans les enjeux tels que la définition de bonnes pratiques pour l'entreprise étendue en vue d'une harmonisation des processus de fabrication. Ces travaux ont été validés au travers d'un démonstrateur sur un cas d'étude industriel comportant plusieurs scénarii. / This work focuses on the knowledge and the data management extracted from the manufacturing to ensure the interoperability in the digital chain. According to the extended enterprise and the factory of the future context, the aeronautics manufacturers tend to a design and manufacturing integrated platform in order to get a right part the first time.This work focus on manufacturing process control and capitalization of know-how from the manufacturing aiming at answering the following issue : How to enable interoperability for the digital production process in order to ensure an integrated and agile design and manufacturing ? This issue is addressed with two proposals : OntoSTEP-NC which focuses on how to model and structure the manufacturing knowledge from the CNC machine and Closed-Loop Manufacturing which focuses on how to re-use and integrate the information feedback from manufacturing to process engineering. Both combined those two proposals address the main issue of this work defining an interoperability framework for the factory of the future and address trends like the definition of guidelines for manufacturing in extended enterprise context. This work has been validated through a demonstrator and an industrial case study with various scenarios.
115

Investigation of FEM numerical simulation for the process of metal additive manufacturing in macro scale / Investigation des simulations macroscopiques en utilisant la méthode MEF pour le procédé de la fabrication additive métallique

Chen, Shuai 05 July 2019 (has links)
La fabrication additive (FA) est devenue une nouvelle alternative pour la fabrication des pièces dans l'industrie. Cependant, il existe encore des limites pour ce procédé, en particulier la forme finale défavorable et les propriétés macroscopiques indésirables des pièces métalliques construites dans les systèmes de FA. La distorsion ou la fissure due à la contrainte résiduelle de ces pièces pose généralement de graves problèmes pour certains types de technologie de la FA métallique. Dans un système de FA, la qualité finale d'une pièce métallique dépend de nombreux paramètres de procédé, qui sont normalement optimisés par une série d'expériences sur des machines de FA. La simulation macroscopique dédiée au procédé de FA est une alternative potentielle pour les pièces métalliques fabriquées par la fabrication additive. Dans cette thèse, nous étudions d'abord le pré-processing de la simulation de FA par la méthode des éléments finis (FEM). Le procédé de fabrication additive est un phénomène multi-physique des champs couplés (champs thermique, mécanique et métallurgique). La simulation macroscopique est réalisée à deux niveaux différents. Au niveau de la couche, la reconstruction du modèle 3D est effectuée à partir du fichier de chemin de balayage de la machine de FA, basée sur la manipulation inverse de l'algorithme d'offsetting-clipping. Au niveau de la pièce, le modèle 3D de CAO est reconstruit dans un maillage des voxels, ce qui est pratique pour une pièce avec une géométrie complexe. Avec les températures de préchauffage différentes et les paramètres du procédé différents, la contrainte résiduelle d'une pièce est analysée. Ces simulations impliquent la technique potentielle pour réduire la contrainte résiduelle par l'optimisation des paramètres du procédé, au lieu de moyens traditionnels par augmenter la température de préchauffage. Basées sur la plateforme de simulation de FEM ci-dessus, deux simulations au niveau de ligne sont également étudiées dans cette thèse, visant à la relation entre le procédé de FA et la qualité finale de la pièce. Ces exemples démontrent la possibilité d'utiliser des simulations macroscopiques pour améliorer le contrôle de la qualité pendant le procédé de FA. Dans la première tâche, l'ensemble de données des paramètres de chauffage et la contrainte résiduelle sont générés par la simulation de FA. La corrélation entre eux est étudiée en utilisant des algorithmes de régression, tel que le réseau neuronal artificiel. Dans la deuxième tâche, un contrôleur de PID pour la boucle de rétroaction puissance-température est intégré dans la simulation de procédé de FA et l'auto-réglage de PID est numériquement étudié au lieu d'utiliser la machine de FA. Les deux tâches montrent le rôle important de la simulation de procédé macroscopique de FA, qui peut remplacer ou combiner les nombreuses expériences essai-erreur dans la fabrication additive métallique. / Additive manufacturing (AM) has become a new option for the fabrication of metallic parts in industry. However, there are still some limitations for this application, especially the unfavourable final shape and undesired macroscopic properties of metallic parts built in AM systems. The distortion or crack due to the residual stress of these parts leads usually to severe problems for some kinds of metal AM technology. In an AM system, the final quality of a metallic part depends on many process parameters, which are normally optimized by a series of experiments on AM machines. In order to reduce the considerable time consumption and financial expense of AM experiments, the numerical simulation dedicated to AM process is a prospective alternative for metallic part fabricated by additive manufacturing. Because of the multi-scale character in AM process and the complex geometrical structures of parts, most of the academic researches in AM simulation concentrated on the microscopic melting pool. Consequently, the macroscopic simulation for the AM process of a metallic part becomes a current focus in this domain. In this thesis, we first study the pre-processing of AM simulation on Finite Element Method (FEM). The process of additive manufacturing is a multi-physics problem of coupled fields (thermal, mechanical, and metallurgical fields). The macroscopic simulation is conducted in two different levels with some special pre-processing work. For the layer level, the reconstruction of 3D model is conducted from the scan path file of AM machine, based on the inverse manipulation of offsetting-clipping algorithm. For the part level, the 3D model from CAD is reconstructed into a voxel-based mesh, which is convenient for a part with complex geometry. The residual stress of a part is analysed under different preheat temperatures and different process parameters. These simulations imply the potential technique of reducing residual stress by the optimisation of process parameters, instead of the traditional way by increasing preheat temperature. Based on the FEM simulation platform above, two simulations at line level are also studied in this thesis, aiming at the relation between the AM process and part's final quality. These examples demonstrate the feasibility of using macroscopic simulations to improve the quality control during the AM process. In the first task, dataset of heating parameters and residual stress are generated by AM simulation. The correlation between them is studied by using some regression algorithm, such as artificial neural network. In the second task, a PID controller for power-temperature feedback loop is integrated into AM process simulation and the PID auto-tuning is numerically investigated instead of using AM machine. Both of the two tasks show the important role of AM macroscopic process simulation, which may replace or combine with the numerous trial and error of experiments in metal additive manufacturing.
116

Návrh robotické linky pro svařování ocelového rámu / Design of a Robotic Cell for a Steel Frame Welding

Kysela, Martin January 2021 (has links)
The aim of this diploma thesis is to design a cell for robotic arc welding of steel frame. Three possible solutions are provided and one of them is to be chosen to work out. Construction designs of fixture, machine guarding and material racks were created and devices and components required for cell functionality were chosen. All of that with regard to the safety of workplace operators.The result is 3D model of welding cell, it´s implementation and virtual commissioning in the simulation software Process simulate. We will verify the weldability of assigned part, find out the production cycle, eliminate error and lastly the technical and economic evaluation will be work out.
117

Archéologie des métallurgies anciennes du cuivre dans le bassin du Niari, République du Congo

Nikis, Nicolas 04 September 2018 (has links) (PDF)
Le cuivre occupe une place importante en Afrique centrale tout au long du second millénaire, notamment dans les échanges. Les gisements du bassin du Niari au sud de la République du Congo, mentionnés dès le 16e siècle dans les sources européennes, ont ainsi joué un rôle économique d’envergure. Ils auraient contribué au développement de plusieurs entités politiques de la zone dont, notamment, le royaume Kongo.Les données directes sur la métallurgie primaire du cuivre dans cette zone restaient cependant limitées à cause du laconisme des sources historiques et de l’insuffisance des données archéologiques. Cette thèse avait donc pour but d’identifier, de dater et de caractériser les différentes productions de cuivre que le bassin du Niari a pu connaître, d’en comprendre le contexte technique, mais aussi sociétal et d’appréhender le rôle que ces productions ont pu jouer à l’échelle régionale, dans les échanges et au niveau sociopolitique. L’étude du matériel céramique et métallurgique récolté lors de trois campagnes de fouilles et de prospections a permis d’identifier plusieurs types de productions métallurgiques différentes rattachées à quatre grandes périodes d’activité entre le 9e et le 19e siècle. La diversité des pratiques métallurgiques et des assemblages céramiques associés suggère une occupation de la zone par des groupes distincts au cours du second millénaire. Ces groupes entretiennent des liens avec d’autres entités culturelles et politiques régionales et leurs productions s’insèrent dans des réseaux d’échanges dont les ramifications sont complexes et multiples. Si l’insertion des zones cuprifères dans ces réseaux varie au cours du temps, certains axes de commerce interrégionaux bien documentés au 19e siècle semblent déjà être bien établis au 14e siècle, attestant ainsi l’ancienneté des échanges sur de longues distances à l’ouest de l’Afrique centrale. / Doctorat en Histoire, histoire de l'art et archéologie / info:eu-repo/semantics/nonPublished
118

Podnikatelský záměr / Entrepreneurial Project

Bartoň, Jan January 2012 (has links)
The theoretical part of this master’s thesis introduces to the reader problems of production management tools, and optimization of the manufacturing process. It explains basic concepts, principles and methods that has aim to clarify systems and methods used in the practical part to the reader. The practical part describes the implementation of these methods and optimization of specific part of the manufacturing process. The result of optimization is evaluated from the perspective of time and finance.
119

Multi-Criteria Decision Support for Manufacturing Process Chains

Reichel, Thomas, Rünger, Gudula 28 March 2013 (has links)
During the manufacturing planning, multiple variants of process chains for the manufacturing of a product to be developed are generated by engineers. In order to select an optimal variant, multiple decision criteria specifying technical, ecological and economical properties of the process chains as well as multiple assessments of different domain experts have to be taken into account. The contribution of this article is a two-step approach that provides a multi-criteria multi-expert assessment of manufacturing process chains supporting the selection of an optimal process chain. A web-based software tool that implements the multi-criteria assessment of process chains is also presented.
120

Field Assisted Roll-to-Roll Manufacturing of Novel Multifunctional Piezoelectric Composites

Armen Yildirim (9148748) 10 September 2022 (has links)
<p>The recent advances in flexible piezoelectric technologies have sparked a great interest in developing multifunctional next-generation transducers and actuators that are increasingly becoming high demand for a range of challenging applications, including self-powered structural and personal health monitoring systems to flexible loudspeaker devices. </p><p>In this research, novel <i>quasi </i>1–3 piezoelectric nanocomposites are introduced with record-high piezoelectric voltage coefficients (g<sub>33</sub>), reaching up to 0.709 Vm N<sup>−1</sup> (approximately 20 percent greater than the recently reported highest g<sub>33</sub> value in the literature). These materials are produced via dielectrophoretic process where both piezoelectric lead zirconate titanate (PZT) nanoparticles and graphene nanoplatelets (GNPs) are simultaneously aligned in a silicone-based polymer matrix (polydimethylsiloxane—PDMS) at a range of concentrations up to 13 vol%, leading to densely structured cone-shaped "nanocolumn forests" in the thickness direction. It is shown that the electric field induced alignment of particles not only improves the overall piezoelectric properties of the composite at relatively low filler concentrations, but also increases the transparency of the system by enabling the light to travel with little scattering or absorption in the “Z” direction through the particle depleted zones created between micro- and nano-sized columns. The details of these unique column morphologies are investigated by various off-line and on-line characterization techniques such as microcomputed tomography—microCT and real-time light transmission measurements to better understand the effect of both material (i.e., concentration) and process-based parameters (e.g., electric field, frequency) on pearl-chain formation. </p><p>To show its versatility and high-performance, the applications comprising both direct (e.g., force sensing, energy harvesting, structural and personal health monitoring) and inverse (e.g., loudspeaker) piezoelectric effect are also demonstrated and extensively characterized. </p><p>Additionally, to demonstrate the scalability of the process, large-area samples are also produced via the continuous dielectrophoretic process (utilizing a novel 44 ft long custom designed multifunctional roll-to-roll (R2R) manufacturing line), resulting in the largest single piece piezoelectric films ever reported in the literature. </p>

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