Дисертації: "Compression of flexible roll"

1

Марусич, Максим Ігорович. "Чотирьохвалковий каландр з модернізацією механізму прогину валка". Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/27146.

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Знайдено шляхи модернізації механізмів компенсації прогину валка і перехрещення валків. Проведено порівняльні розрахунки базових конструкцій та модернізованої а також параметричні, кінематичні, теплові розрахунки та розрахунки на міцність, які підтверджують працездатність агрегату та доцільність обраної модернізації. Розроблено start-up проект в якому були проаналізовані всі можливості та загрози майбутнього виробництва, визначено сильні та слабкі сторони за рахунок яких є можливість виходу на провідні позиції в виробництві лінолеуму та реліну.
After conducting literature and patent examinations, ways were found to modernize the mechanisms for compensating the roll deflection and the intersection of the rolls. Comparative calculations of basic structures and modernized, as well as parametric, kinematic, thermal calculations and strength calculations, confirming the efficiency of the unit and the feasibility of the selected modernization, are carried out. A start-up project was developed in which all the possibilities and threats of future production were analyzed, strengths and weaknesses were identified due to which it is possible to reach leading positions in the production of linoleum and relien. developed a scheme of automation and measures of labor protection.
Найдены пути модернизации механизмов компенсации прогиба валка и пересечения валков. Проведены сравнительные расчеты базовых конструкций и модернизированной а также параметрические, кинематические, тепловые расчеты и расчеты на прочность, подтверждающие работоспособность агрегата и целесообразность выбранной модернизации. Разработан start-up проект в котором были проанализированы все возможности и угрозы будущего производства, определены сильные и слабые стороны за счет которых есть возможность выхода на ведущие позиции в производстве линолеума и релина.

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Mccracken, David Ivan. "The development of a more flexible roll bending process." Thesis, Ulster University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516523.

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3

Zhang, Jin. "Low-Cost Industrial Manufacturing of CIS-Based Flexible Solar Panels Using Roll-to-Roll Technology." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/244825.

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Harnessing the power of the sun through photovoltaic cells is a new area of research and development and may hold the key to sustainable energy on earth. Currently, solar cells and panels with high efficiencies have been successfully created on a laboratory scale. However, in order for solar panels to be marketable and serve as a realistic replacement for current energy sources, a large-scale, high-throughput, and low-cost production system must be devised that is competitive with very cheap fossil fuels that currently dominate the market. The goal of this project is to mass scale the production and manufacturing of inorganic solar cells using cost-effective, roll-to-roll printing methods. Annually, 676 MW of power will be produced, representing 71% of the total US market share for photovoltaic technology, and sold to market at the price of $1/Watt. The design of the solar cell is based on a CuInS₂ absorber layer, ZnS buffer layer and ZnO and ZnO:Ga window layer. The film is printed on a flexible aluminum substrate, 20 inches wide, at a continuous rate of 100 ft/min and a silver-based metal contact is deposited on top. Over the project lifetime, a net present value assuming a 15% nominal interest of $1.7 billion is anticipated.

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4

Kojimoto, Nigel Costello. "Ultrasonic inspection methods for defect detection and process control in roll-to-roll flexible electronics manufacturing." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101811.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 97-100).
Roll-to-roll flexible electronics manufacturing technologies require new sensing and measurement capabilities for defect detection and process control. This body of work investigates the use of ultrasound, specifically Lamb and longitudinal waves, as a sensing modality and measurement technique for thin film roll-to-roll manufacturing. A variety of custom wedges were designed and machined from multiple materials to test their suitability at launching ultrasonic Lamb waves along Polyethylene Terephthalate (PET) film. Using hydrogel wedges, the fundamental antisymmetric (Ao) Lamb wave mode was successfully propagated a distance of 2 cm. ABS wedges were found to initiate longitudinal waves, which were detected at a distance of 5 cm. InstronTM based extension-tensile experiments revealed that the longitudinal wave is affected by tension in the PET, exhibited by a general increase in attenuation and a decrease in wave speed during plastic deformation; such variation may have process control applications.
by Nigel Costello Kojimoto.
S.M.

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5

Tobin, Vincent. "Roll-to-roll deposition of highly flexible organic-inorganic barrier layers for printed electronics and photovoltaics." Thesis, University of Oxford, 2018. https://ora.ox.ac.uk/objects/uuid:d6ea9bcb-171d-4fc6-95e4-51d0e8d4351a.

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This thesis investigates how to improve transparent flexible water vapour barriers by understanding how water permeates through them. The barriers consisted of a reactively sputtered aluminium oxide coating on an industrial-grade polypropylene substrate. Some also incorporated a di-acrylate smoothing layer. Key deposition conditions were studied and optimised for permeation and visible-light transparency: sputtering power, thickness & sequential deposition rate. One of the main deposition conditions corresponded to increasing coating nitrogen content in order to induce barrier-water interaction. The final investigation consisted of including acrylate layers in different barrier stacking combinations. It was found that thin, high sputter power coatings formed the best barriers to permeation. This was due to denser packing of the oxide and the inclusion of fewer macro-defects (large defects allowing unhindered permeation) and nano-defects (defects small enough to cause the permeant to interact with the coating). No clear benefit to permeation was found from the inclusion of nitrogen, but refractive index was seen to increase and the oxynitride coatings mechanically failed at a greater force than the oxides. This case illustrated the importance of considering the role of permeation through nano-defects: although a high activation energy was achieved for the nitrogen containing films, possibly suggesting greater interaction between the water vapour and the barrier, the amount of permeation was not reduced as the nitrogen gave rise to increased permeation due to nano-defects, thus changing the processing and chemistry can affect both the macro-defect and nano-defect permeation. Smoothing layers were found to reduce the permeation rate by covering large substrate features, thus allowing rough substrates to be used even for high barriers. Although a coating of acrylate on top of a barrier oxide showed no improvement, a 1-2-1-2 stack of smoothing layer (1) and oxide (2) was found to exhibit a large delay in the onset of permeation.

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6

Lindgren, Michael. "Experimental and computational investigation of the roll forming process." Doctoral thesis, Luleå : Division of Material Mechanics, Luleå University of Technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3340038.

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7

Mulder, Aart. "Robust and flexible hardware implementation of ITU-G4." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-24022.

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This project was carried out as thesis work during the last semester of my Master studies Electronics Design at the Mid Sweden University. Firstly, it considers a robust and exible implementation of ITU-G4 in hardware based on earlier work, and secondly, it covers review of related work and investigation in the weaknesses of two published designs. More specically, it is an investigation on the robustness of the previously developed VHDL implementation ofthe ITU-G4 algorithm. This includes designing of a debug interface to track the compression process inside the FPGA. The nal result, when comparing to earlier work and other published designs, the ITU-G4 compression performs without any glitches or crashes at certain patterns. The maximum frame rate the design can run at is 60fps at a frame size of 752x480 and clockrate of 33.3MHz. The design is tested with three sets of images: easy, medium and complexwhich are all successfully compressed. This includes imperfect images of bar-codes and Q-codes without the need of morphological preprocessing when comparing to the published design that needs preprocessing for medium and complex images to remove unexpected transitions.

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8

Guo, Yuanhao. "FUNCTIONAL POLYMER FILM ROLL-TO-ROLL MANUFACTURING BY FIELD ASSISTED ALIGNMENT OF NANOPARTICLES/PHASES IN THICKNESS "Z" DIRECTION." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1480441013340037.

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9

Yepez, Denisse E. "Analysis of a mechanical punching process to create registration holes on a continuous roll-to-roll flexible electronics substrates using SPC techniques." Diss., Online access via UMI:, 2008.

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Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008.
Includes bibliographical references.

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10

Ahmadian, Alireza. "Flexible medical image transmission and compression schemes using multiresolution orthagonal wavelet transform." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300006.

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11

Buffham, Timothy M. D. "Isotropic rubber moulding." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/27907.

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The current work was initiated to develop, understand and optimise a novel computer controlled, automated, flexible compression moulding system primarily for the production of fluid seals. A prototype moulding system was designed and built for the study. It was used to process a range of rubber compounds for process evaluation.

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12

Jong, Jae Ho. "Characteristics of jet impingement, drainage and compression in a forming roll of a twin-wire machine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/NQ41558.pdf.

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13

Chomier, Mickael Thierry. "Effect of Vortex Roll-up and Crevice Mass Flow on Ignition in a Rapid Compression Machine." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1374666527.

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14

Loverich, James S. "Life Prediction of Composite Armor in an Unbonded Flexible Pipe." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35873.

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Composite materials are under consideration for the replacement of steel helical tendons in unbonded flexible pipes utilized by the offshore oil industry. Higher strength to weight ratios and increased corrosion resistance are the primary advantages of a composite material for this application. The current study focuses on the life prediction of a PPS/AS-4 carbon fiber composite proposed for the above employment. In order to accomplish this task, the properties of the material were experimentally characterized at varying temperatures, aging times and loadings. An analytic technique was developed to predict tensile rupture behavior from bend-compression rupture data. In comparison to tensile rupture tests, bend-compression rupture data collection are uncomplicated and efficient; thus, this technique effectively simplifies and accelerates the material characterization process. The service life model for the flexible pipe composite armor was constructed with MRLife, a well established performance simulation code for material systems developed by the Materials Response Group at Virginia Tech. In order to validate MRLife for the current material, experimental data are compared to life prediction results produced by the code. MRLife was then applied to predict the life of the flexible pipe composite armor in an ocean environment. This analysis takes into account the flexible pipe structure and the environmental and mechanical loading history of an ocean service location. Several parameter studies of a flexible pipe in a hypothetical environment were conducted. These analyses highlight certain loadings and conditions which are particularly detrimental to the life of the material.
Master of Science

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15

Thiesse, Jean-Marc. "Codage vidéo flexible par association d'un décodeur intelligent et d'un encodeur basé optimisation débit-distorsion." Nice, 2012. http://www.theses.fr/2012NICE4058.

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Cette thèse est dédiée à l’amélioration des performances de compression vidéo. Deux types d’approches, conventionnelle et en rupture, sont explorées afin de proposer des méthodes efficaces de codage Intra et Inter pour les futurs standards de compression. Deux outils sont étudiés pour la première approche. Tout d’abord, des indices de signalisations sont habilement traités par une technique issue du tatouage permettant de les masquer dans les résiduels de luminance et de chrominance de façon optimale selon le compromis débit-distorsion. La forte redondance dans le mouvement est ensuite exploitée pour améliorer le codage des vecteurs de mouvement. Après observation des précédents vecteurs utilisés, un fin pronostic permet de déterminer les vecteurs résiduels à privilégier lors d’une troisième étape de modification de la distribution des résiduels. 90% des vecteurs codés sont ainsi pronostiqués, ce qui permet une nette réduction de leur coût. L’approche en rupture vient de la constatation que H. 264/AVC et son successeur HEVC sont basés sur un schéma prédictif multipliant les choix de codage, les améliorations passent alors par un meilleur codage de la texture à l’aide d’une compétition accrue. De tels schémas étant bornés par la signalisation engendrée, il est alors nécessaire de transférer des décisions au niveau du décodeur. Une approche basée sur la détermination conjointe au codeur et au décodeur de paramètres de codage à l’aide de partitions causales et ainsi proposée et appliquée aux modes de prédiction Intra et à la théorie émergente de l’échantillonnage compressé. Des performances encourageantes sont reportées et confirment l’intérêt d’une telle solution innovante
This Ph. D. Thesis deals with the improvement of video compression efficiency. Both conventional and breakthrough approaches are investigated in order to propose efficient methods for Intra and Inter coding dedicated to next generations video coding standards. Two tools are studied for the conventional approach. First, syntax elements are cleverly transmitted using a data hiding based method which allows embedding indices into the luminance and chrominance residuals in an optimal way, rate-distortion wise. Secondly, the large motion redundancies are exploited to improve the motion vectors coding. After a statistical analysis of the previously used vectors, an accurate forecast is performed to favor some vector residuals during a last step which modifies the original residual distribution. 90% of the coded vectors are efficiently forecasted by this method which helps to significantly reduce their coding cost. The breakthrough approach comes from the observation of the H. 264/AVC standard and its successor HEVC which are based on a predictive scheme with multiple coding choices, consequently future improvements shall improve texture by extensively using the competition between many coding modes. However, such schemes are bounded by the cost generated by the signaling flags and therefore it is required to transfer some decisions to the decoder side. A framework based on the determination of encoding parameters at both encoder and decoder side is consequently proposed and applied to Intra prediction modes on the one hand, and to the emerging theory of compressed sensing on the other hand. Promising results are reported and confirm the potential of such an innovative solution

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Mazor, Alon. "Modelling of roll compaction process by finiite element method." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2017. http://www.theses.fr/2017EMAC0009/document.

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Dans l’industrie pharmaceutique, la granulation sèche par compactage à rouleaux est un procédé d’agglomération de poudres en granulés pour améliorer les propriétés d’écoulement nécessaire pour le procédé de compression en matrice. Comprendre le procédé de compactage à rouleaux et optimiser l’efficacité de production est limitée par l’utilisation de l’approche expérimentale à cause du coût élevé des poudres, le temps des essais et la complexité du procédé. Dans ce travail, une méthode d’éléments finis en 3D, est développée dans le but d’identifier les paramètres critiques du matériau et du procédé pour le contrôle de la qualité de la production. Le modèle de comportement de Drucker-Prager Cap est utilisé pour décrire le comportement en compression de poudres et sa calibration est déterminée à partir des essais standard. Pour surmonter la complexité liée à l’existence de deux mécanismes différents, l’alimentation en poudre par une vis sans fin et le compactage entre les rouleaux, une nouvelle méthode d’interfaçage entre la méthode des éléments discrets (DEM) employée pour décrire l’écoulement dans l’alimentation et la méthode des éléments finis (FEM) utilisée pour le compactage entre les rouleaux est développée. Enfin, pour une modélisation de compactage de rouleaux plus réaliste, prenant en compte la variation de l’entrefer entre les rouleaux, une nouvelle approche de couplage Euler-Lagrange est proposée. Les résultats de simulations par éléments finis montrent clairement l’effet des différents paramètres du procédé sur les distributions de pression et de densité dans la zone de compactage. En outre, les résultats montrent que l'utilisation de plaques de confinement de la poudre entre les rouleaux, développe une distribution de pression et de densité non homogène dans le compact, avec une densité plus élevée au centre et plus faible aux bords. D'autre part, l’utilisation de rouleaux dont l’un est surmonté d’une jante de confinement, a montré une distribution de propriétés globalement plus uniforme sur la largeur du compact avec des valeurs légèrement plus élevées aux bords qu’au centre. La méthodologie combinant les méthodes DEM & FEM montre clairement une corrélation directe entre la vitesse des particules entraînées par la vis dans la zone d’alimentation et la pression du rouleau. Tous les deux oscillent avec la même période. Cela se traduit par un compact anisotrope avec un profile de densité variant de manière sinusoïdale le long de sa largeur. Afin d'étudier la capacité du modèle à prédire les propriétés des compacts produits par compactage à rouleaux, les prédictions par simulations numériques sont comparées aux données de la littérature et validées par des mesures spécifiques
In the pharmaceutical industry, dry granulation by roll compaction is a process of size enlargement of powder into granules with good flowability for subsequent die compaction process. Understanding the roll compaction process and optimizing manufacturing efficiency is limited using the experimental approach due to the high cost of powder, time-consuming and the complexity of the process. In this work, a 3D Finite Element Method (FEM) model was developed to identify the critical material properties, roll press designs and process parameters controlling the quality of the product. The Drucker-Prager Cap (DPC) model was used to describe the powder compaction behavior and was determined based on standard calibration method. To overcome the complexity involving two different mechanisms of powder feeding by the screw and powder compaction between rolls, a novel combined approach of Discrete Element Method (DEM), used to predict the granular material flow in the feed zone and the Finite Elements Method (FEM) employed for roll compaction, was developed. Lastly, for a more realistic roll compaction modelling, allowing the fluctuation of the gap between rolls, a Coupled-Eulerian Lagrangian (CEL) approach was developed. FEM simulation results clearly show the effect of different process parameters on roll pressure and density distribution in the compaction zone of powder between the rolls. Moreover, results show that using a cheek-plates sealing system causes a nonuniform roll pressure and density distribution with the highest values in the middle and the lowest at the edges. On the other hand, the resultant pressure and density distributions with the rimmed-roll obtained higher values in the edges than in the middle and overall a more uniform distribution. The combined DEM-FEM methodology clearly shows a direct correlation between the particle velocity driven by the screw conveyor to the feed zone and the roll pressure, both oscillating in the same period. This translates into an anisotropic ribbon with a density profile varying sinusoidally along its length. To validate the results, the simulations are compared with literature and experimentally measured values in order to assess the ability of the model to predict the properties of the produced ribbons

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17

Amarante, Rodrigo de Almeida. "Compressão dinâmica em risers." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-11082015-154505/.

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O presente trabalho foi realizado por meio de uma abordagem tríplice do problema de compressão dinâmica em risers, fundamentado em ensaios em um Calibrador Hidrodinâmico, com posterior confrontação dos resultados com formulações analíticas e o uso de programas comerciais dedicados ao estudo da estática e dinâmica de linhas flexíveis. O principal objetivo foi a determinação acurada, a partir de uma instrumentação pouco invasiva, dos comprimentos das ondas de flexão geradas no TDP, durante a compressão dinâmica. Esse objetivo, de per si, encerra o caráter de ineditismo da presente tese. Os ensaios consistiram na realização de movimentos circulares no topo de um modelo flexível lançado em catenária, sob diversas configurações, totalizando um total de 72 experimentos: foram utilizados três frequências de movimento, três amplitudes, quatro ângulos de topo e dois sentidos de rotação. Um sistema de monitoramento óptico foi utilizado como principal instrumentação. Além desse equipamento, foi utilizada uma célula de carga, posicionada entre o equipamento que prescrevia os movimentos ao modelo flexível e uma rótula, que permitia que a célula de cargas e movimentasse solidariamente ao sistema. Rotinas numérica próprias foram utilizadas para o pós-processamento dos dados obtidos. Os resultados foram, então, comparados com formulações analíticas constantes da literatura, bem como a adaptação da equação para a carga crítica de flambagem de vigas curvas, para as condições de contorno dos ensaios realizados. Como resultado principal, é possível citar a confirmação experimental da suposição corrente com relação ao número de onda associado às ondas de flexão geradas na compressão dinâmica, até então assumida como uma hipótese ad hoc. Além disso, o procedimento adotado, embasado teoricamente, foi utilizado desde o estabelecimento do material com que o modelo foi construído, passando pela elaboração racional da matriz de ensaios e finalizando com as análises realizadas, quando os resultados experimentais foram confrontados com as previsões analíticas.
This work was carried out through a threefold approach to dynamic compression in risers, based on tests in a Hydrodynamic Calibrator, with subsequent comparison of results with analytical formulations and the use of commercial softwares dedicated to the study of static and dynamic flexible lines. The main aim was an accurate determination, from a minimally invasive instrumentation, the lengths of flexural waves generated in the TDP, during dynamic compression. This goal, in itself, is the novelty of this thesis. The tests consisted in performing circular motion on top of a flexible catenary model launched under several conditions, amounting to a total of 72 experiments: three motion frequencies, three imposed amplitudes , four top angles and clockwise and counter-clockwise rotation. A tracking monitoring system was used as main instrumentation. In such equipment, a load cell was used, positioned between rotor used to prescribe top movements at the top of a flexible model, allowing the load cell jointly move around a bar conected to the shaft motor. Numerical routines, made by author, were used for data post-processing. The results were then confronted with analytical formulations from specialized literature, as well as the adaptation of the equation for the buckling critical load for curved beams under the boundary conditions of the tests. As a main result, it is possible to mention the experimental confirmation of the current assumption with respect to the wave number associated with bending waves generated during the dynamic compression, hitherto assumed as an ad hoc hypothesis. In addition, the procedure adopted, based in analytical theories, was used since the establishment of the material with which the model is built, through the rational development of the test matrix and ending with the analyzes carried out when the experimental results were compared with analytical predictions.

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Nugay, Isik Isil. "POLYURETHANES in RIGID and FLEXIBLE ELECTRONICSNOVEL HYBRID PROCESSING TECHNIQUES and REAL-TIME MONITORING OF MATERIAL PROPERTIES." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1406633847.

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19

Vanzella, Leonardo Antonio. "Formatação de pulso em sistemas coerentes Nyquist-WDM." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18155/tde-02082017-164818/.

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Анотація:

A necessidade de transmissão de canais modulados a taxas a partir de 400 Gb/s tem motivado a pesquisa e os esforços relativos às tecnologias de camada física habilitadores desta alta capacidade. A atenção se volta, principalmente, aos frontends (transmissores e receptores), aliados aos processadores digitais de sinal (Digital Signal Processors, DSPs), às técnicas de amplificação óptica e a novos tipos de fibra óptica. Em particular a técnica baseada no emprego de filtros de Nyquist combinados à multiplexação de comprimentos de onda (Wavelength Division Multiplexing, DWM), conhecida como Nyquist-WDM, ou N-WDM, tem atraído grande interesse para geração de supercanais ópticos, hoje um dos elementos chave nos sistemas de redes ópticas. O estudo dos fundamentos e casos particulares dos filtros de Nyquist são aprofundados nesta dissertação para o controle de seus parâmetros, em especial o parâmetro conhecido como fator de roll-off, em aplicações que requerem flexibilidade na ocupação espectral e até o reaproveitamento das limitações do filtro para atenuar alguns efeitos lineares e não lineares na fibra. A técnica utiliza um tipo de formatação geométrica de pulso e é limitada pelo ajuste grosso do fator de roll-off, mas como abordagem inicial, permite estabelecer uma série de compromissos na concepção do circuito eletrônico de um transponder sintonizável. Uma investigação teórica foi feita em um sistema PM-16QAM de 21x256 Gb/s, a partir de dados experimentais obtidos com roll-off igual 0,1, para análise do efeito no desempenho sistêmico do ajuste do excesso de largura de banda (em relação à banda de Nyquist) de um filtro formatador de pulso. O fator de roll-off foi ajustado e seu impacto no desempenho do sistema, em termos de alcance, foi verificado. A partir dos resultados, foi observado que, desde que a taxa de erro de bit, BER, esteja dentro do limite do código corretor de erro (forward error corrector, FEC), o valor de roll-off pode ser ajustado para um valor ótimo de acordo com a configuração do sistema e as metas requeridas. Uma vez encontrada a relação entre a BER e o fator de roll-off, foi possível determinar um fator de mérito que relaciona a resolução do filtro de Nyquist, em função do número de taps que ele emprega, o consumo de energia da DSP e, consequentemente, a BER. O compromisso assim estabelecido entre o desempenho sistêmico, o consumo de energia e o fator de roll-off representa a principal contribuição desta dissertação.
The need for transmission of channels modulated at rates greater than 400 Gb/s has motivated the research and efforts related to the physical layer technologies that will enable this high capacity. The attention turns mainly to the frontends (transmitters and receivers), allied to digital signal processors (DSPs), optical amplification techniques and new types of optical fiber. The technique based on the use of Nyquist filters combined withWavelength Division Multiplexing (WDM), known as Nyquist-WDM, or N-WDM, has attracted great interest for the generation of optical super-channels, today one of the key elements in optical network systems. The study of the fundamentals and particular cases of the Nyquist filters are detailed in this dissertation for mastering the control of the parameters, especially the parameter known as roll-off factor, for applications that require flexibility in the spectral occupation and even the reutilization of the limitations of the filter to attenuate some linear and non-linear effects on the fiber. The technique uses a geometric type of pulse-shaping, and is limited by the roll-off factor tunning, but as an initial approach, it allows to establish a series of compensations in the design of the electronic circuit of a tunable transponder. A theoretical investigation was made on a 21x256 Gb/s PM-16QAM system, taken as reference the experimental data obtained with roll-off equal to 0.1, to analyze the effects of adjusting the excess bandwidth (relative to the Nyquist band) of a pulse-shaping filter. The roll-off factor was tunned and its impact on the system performance in terms of range effects was verified. From the results, it was observed that, as long as the bit error ratio, BER, is within the FEC limit, the roll-off parameter can be set to an optimum value according to the system configuration and required targets. Once the relationship between the BER and the roll-off factor was found, it was possible to determine a merit factor that relates the resolution of the Nyquist filter, as a function of the number of taps it uses, the energy consumption of the DSP and, consequently, the BER. The compromise thus established between system performance, energy consumption and roll off represents the main contribution of this work.

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20

Zhang, Jie. "Contribution aux développements des technologies de compression polymères chargés pour la réalisation d'inserts métalliques micro-structurés." Thesis, Besançon, 2013. http://www.theses.fr/2013BESA2044/document.

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Les travaux menés dans le cadre de cette thèse sont focalisés sur les procédés deréplication permettant la transformation des mélanges en composants par les technologiesen séquentiel ou bien en continu, selon les applications visées. Les développementsconcernent la mise en place et l’hybridation de différents procédés de micro-réplication(estampage à chaud de polymère thermoplastique et par laminage circulaire entre deuxrouleaux). Ces deux procédés sont développés et optimisés pour l’élaboration decomposants micro-structurés ou de microcomposants possédant des propriétésfonctionnelles mécaniques ou thermo-physiques requises à partir de différents mélangeschargés en poudres métalliques ou en nanotubes de carbone. Des exemples de réalisationde composants structurés, à base d’un système micro-fluidique possédant plusieurs canauxde 200 microns par 200 microns et des réservoirs de diamètre de 2 mm, sont prises commeexemple tout au long de ces travaux de cette thèse. Différents travaux de caractérisationsont été entrepris pour optimiser les procédés de micro-réplication par estampage à chaud etpar laminage circulaire entre deux rouleaux
The Ph.D subject concerns the study of two micro-replication processes by hotembossing and roll to roll processes for thermoplastic polymers and loaded polymers withpowders or carbon nanotubes. The micro-replication processes, realized in sequential orcontinuous ways, use some different elaborated loaded feedstocks in order to obtainstructural components or micro-component with high aspect ratio and mechanical orthermo-physical properties.A chain combining hot embossing and roll embossing and powder metallurgy have beendeveloped in our lab and investigated. The different micro mould die cavities have beenrealized with different micro-manufacturing process, elastomeric mould has been obtainedby casting process. Finally, a metallic structured die cavity has been obtained by combininghot embossing and debinding and sintering stages. The second topic is the comparison ofmetallic die cavity mould obtained by roll embossing or rolls embossing. Two demonstratorshave been developed during the preparation of this Ph.D period: first a metallic micro-fluidicsystem with micro-structuration with diameter of 1 mm for the reservoir and 200 microns by200 microns for the channel have been realized and characterized by different methods.Secondly, some functional micro-component has been obtained with carbon nanotube andsome specific properties in terms of mechanic and thermo-physical properties have beencharacterized

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21

Martz, Yannick. "Modélisation et commande de systèmes d'entraînement de bandes flexibles : nouvelles approches à l'aide des éléments finis." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAD016.

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Les systèmes d'entraînement de bandes flexibles sont utilisés dans la production d'une très grande variété de produits du quotidien mais également dans la métallurgie et dorénavant pour la production des nouvelles technologies. L'amélioration des systèmes industriels d'entraînement de bandes est un problème difficile car ils sont de grande dimension, non-linéaires, à paramètres variant et incertains. Ils possèdent un fort couplage entre les différentes parties (mécanique et commande) à cause de la bande qui relie les éléments. Il faut donc améliorer la chaîne de production par une approche pluridisciplinaire. Les objectifs sont de maîtriser les paramètres clés de ces systèmes afin de garantir les cadences de production et les précisions demandées de plus en plus importantes. Il faut également réduire les défauts les plus récurrents, notamment les plis de bande. Or jusqu'à présent seuls des modèles 1D étaient utilisés. Ils sont indispensables pour la synthèse de commande et les études fréquentielles mais ne permettent pas d'étudier des phénomènes complexes tels que les plis de bande. Une nouvelle approche d'étude de ces systèmes est développée. Dans un premier temps, des améliorations de structures de commandes sont proposées. Dans un second temps un modèle 3D par éléments finis utilisant un algorithme de dynamique multicorps flexibles est développé et utilisé pour étudier les plis de bande par comparaison à la théorie classique de prédiction de ces défauts. Dans un troisième temps un simulateur complet est développé comprenant le modèle 3D mécanique par élément finis couplé à la partie commande (co-simulation)
Roll-to-Roll systems are used in the manufacturing of a wide variety of everyday products as well as in metallurgy and for the manufacturing of new technologies. The improvement of Roll-to-Roll systems is a difficult problem because they are large, non-linear, with varying and uncertain parameters. They have a coupling between the different parts (mechanical and control) with the help of the web connecting the elements. It is therefore necessary to improve the process line through a multidisciplinary approach. The objectives are to master the key parameters of these systems in order to guarantee the manufacturing rates and the more important accuracies requested. It is also necessary to reduce or remove the most recurring defects such as web wrinkles. Until now, only 1D models were used. They are essential for control synthesis and frequency studies but they do not allow to study complex phenomena such as web wrinkles. A new approach for studying these systems is developed. First, improvements of control structures are proposed. Secondly, a 3D finite element model using a flexible multibody dynamics algorithm is developed, used in this work to study web wrinkles and compared to the classical prediction theory of these defects. Finally, a complete simulator is developed including the mechanical 3D model by finite element coupled to the control part (co-simulation)

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22

Neto, Rogerio Silveira Bezerra. "Análise comparativa de pavimentos dimensionados através dos métodos empírico do DNER e mecanístico e proposta de um catálogo simplificado de pavimentos para a região de Campo Grande (MS)." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-03052004-153504/.

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Este estudo tem como objetivo principal comparar estruturas de pavimentos flexíveis projetadas através dos métodos empírico do DNER e mecanístico, considerando-se alguns materiais de pavimentação utilizados na região de Campo Grande, estado do Mato Grosso do Sul. Como objetivos decorrentes, pode-se destacar a obtenção das características resilientes e de fadiga destes materiais e a proposta de um catálogo simplificado de estruturas de pavimentos para a referida região. Para a efetivação da pesquisa, foram coletados materiais típicos do subleito da região e daqueles mais utilizados na composição de bases e capas dos pavimentos locais. Após as suas caracterizações, realizaram-se ensaios de compactação, CBR, triaxiais cíclicos e compressão diametral estática e dinâmica. As análises mecanísticas foram realizadas utilizando-se o programa computacional FEPAVE, que leva em conta o comportamento elástico não-linear dos materiais, considerando-se o critério de confiabilidade. A partir da análise comparativa dos métodos de dimensionamento, observou-se que, ora as estruturas estabelecidas pelo método mecanístico são idênticas às determinadas pelo método do DNER, ora são mais esbeltas, ora são menos esbeltas, dependendo do tipo de material que constitui as camadas e do nível de confiabilidade adotado. Verificou-se ainda que a caracterização dos materiais através dos ensaios de módulo de resiliência, vida de fadiga e deformação permanente é imprescindível quando se deseja projetar um pavimento empregando-se o método mecanístico. Por fim, elaborou-se um catálogo simplificado de pavimentos flexíveis para a região de Campo Grande MS, com as intenções de contemplar o uso de materiais locais e auxiliar os engenheiros na concepção de seus projetos
This study has as main objective to compare structures of flexible pavements designed by two different methods, the DNER empirical method and the mechanistic method, being considered some paving materials used in the area of Campo Grande, state of Mato Grosso do Sul. As secondary objectives, it can stand out the obtaining of the mechanical properties of these materials and the proposal of a simplified catalog of flexible pavements for the referred area. For the accomplishment of the research, typical materials of subgrade, base course and surface layer were collected. After their characterizations, tests of compaction, CBR and repeated load were executed. The mechanistic analyses were accomplished being used the software FEPAVE, that takes into account the non-linear resilient modulus of the materials, being considered the reliability criterion. Starting from the comparative analysis of the design methods, it was observed that the structures established by the mechanistic method can be identical, more slender or less slender to the ones obtained by the empirical method, depending on the type of the material that constitutes the layers and the reliability level adopted. It was also verified that the characterization of the materials by repeated load tests (resilient modulus, fatigues life and permanent deformation) is indispensable when one want to project a pavement being used the mechanistic method. Finally, a simplified catalog of flexible pavements was elaborated for the area of Campo Grande MS, with the intentions of to contemplate the use of local materials and to aid the engineers in the conception of their projects

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23

Xin, Hao. "Toward roll-to-roll transfer of large-scale graphene for flexible electronics fabrication." Thesis, 2013. http://hdl.handle.net/2152/28500.

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Graphene is a promising material for flexible electronics due to its extraordinary electrical, mechanical, and optical properties. One of the biggest challenges today is to transfer large-scale graphene sheet to flexible substrates with minimal quality degradation. In this thesis, a bilayer polymer support for graphene transfer is proposed. Liquid PDMS (polydimethylsiloxane) is first coated on graphene to conform to its surface morphology. A flexible plastic substrate is then pressed on PDMS as a durable support. After PDMS is cured, electrochemical delamination is used to separate graphene from the copper foil. Due to the extremely low work of adhesion between graphene and PDMS, the graphene film on PDMS can be further transferred onto silicon wafer or other flexible substrates by simple adhesion. An added benefit of the PDMS layer is its strain isolation effect, which could protect graphene-based devices from breaking under external loads applied on the flexible substrate. The strain isolation effect of PDMS is verified with an analytical model and finite element analysis. The design of a prototype roll-to-roll graphene transfer machine is also presented.
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24

Riza, Mehdi. "Mechanical Design and Analysis: High-Precision Microcontact Printhead for Roll-to-Roll Printing of Flexible Electronics." 2021. https://scholarworks.umass.edu/masters_theses_2/1022.

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Flexible electronics have demonstrated potential in a wide range of applications including wearable sensors, photovoltaics, medical devices and more, due to their properties of extreme adaptability while also being lightweight and highly robust. The main challenge standing in the way of progress in this field is the difficulty of large-scale manufacturing of these flexible electronics compared to their rigid counterparts. Microcontact printing is a form of soft lithography in which an elastomeric stamp is used to transfer sub-micron scale surface patterns onto a flexible substrate via ink monolayers. The integration of microcontact printing into a roll-to-roll (R2R) system will enable continuous printing of flexible electronics and scale it up for massive manufacturing. The proposed thesis outlines a novel mechanical design for a microcontact printer which utilizes flexural motion stages with integrated position and force sensors to control the print process on a R2R system. The printhead is designed to fit the available space on the pre-installed UMass Amherst Intelligent Sensing Laboratory test table and breadboard. The R2R system includes motorized rollers for winding/unwinding the PET (polyethylene terephthalate) web substrate, and idler rollers for guiding a web through the print system. As the central element to this design, two matching plate flexures are designed on the two ends of the printer roller to control the tilting and positioning of the print roller. Flexure mechanisms rely on bending and torsion of flexible elements: this allows them to achieve much higher precision in positioning compared to conventional mechanisms which rely on surface interaction between multiple moving parts. The print resolution target for this design is 500 nm (linewidth), based on current state-of-the-art designs [1, 2]. In the initial version of the printhead design, a total of 33 parts are custom fabricated for assembly and installation in the R2R system lab setup. These include everything from the components of the print roller, specially adapted air-bearing mounts, support structures, and connectors. The design and 4 fabrication process for every component is outlined here along with the functionality, as every component was designed with the system objectives and constraints in mind. Using SolidWorks simulation, FEA (finite element analysis) is performed for every part of the assembly that is subjected to stress in the real system, so that predictions can be made about the displacement of the motion stages and the frequency of vibration. These predictions are evaluated by comparation with the experimental results from tests conducted on the real system hardware and used to assess the quality of the fabricated assembly. The work performed in this thesis enables advancements in the assembly of an updated, optimized R2R system and has led to an experimentally functioning lab setup that is ripe for further improvements. Completion and calibration of this augmented R2R system will, in future, enable UMass Amherst in-house production of large-area flexible electronics which may be used in a wide range of applications, including medical sensors, solar cells, displays, and more. In addition to microcontact printing, this R2R system may also be applied to nanoimprint lithography, another contact-based print method, or integrated with inkjet printing, a non-contact method.

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25

Chen, Yen-Gu, and 陳彥谷. "Dynamics and Control of Maglev Flexible Rotors under Axial Compression." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/83072298829597016374.

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Анотація:

碩士
國立成功大學
機械工程學系碩博士班
95
The analysis of the dynamics and stability of vertical flexible rotors under axial forces is studied in this thesis. In order to keep flexible rotors asymptotically stable, the technology of magnetic bearing and design of sliding mode control/fuzzy sliding mode control loop are incorporated to practically stabilize flexible rotors. The two phenomena, buckling and whirling, are caused as the rotor is spinning at high speed. Take the rotary inertia and gyroscope effect into account, the motion of the flexible rotors is analyzed on the basis of the Rayleigh beam theory. Depending on the whirling frequency equation and mode shape of the flexible rotors, the dynamics and stability of the flexible rotors is investigated, and the critical speed and critical load of the buckling and whirling of rotors system can be obtained. The governing equation of the maglev rotors is derived via the mathematical model of the magnetic bearing and the motion of the flexible rotors. By singular perturbation technology, the system model can be transformed into reduced order model which is the basis of the controller design. For overcoming the uncertainty of system parameter and reducing the effect due to mass eccentricity, the fuzzy sliding mode controller (FSMC) is employed in this thesis. The simulation results show that FSMC has good performance, satisfying the specification of the system response which is designated what users normally expect.

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26

JI, HUNG-RU, and 紀宏儒. "Flexible roll forming process design for variable width U-shape product." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/5eqep3.

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碩士
國立高雄應用科技大學
模具工程系
104
This thesis investigates the geometrical precision of a three-dimensional flexible roll forming products with respect to the process parameters. The geometrical parameters such as height of rib, bending radius of the cross section, variation of with were studied for the forming process design of a U-shaped panel with variable width in the longitudinal direction. The study of the flexible roll forming process include the mathematical model of neutral line, the blank development, the forming pass determination, the roll design, the forming path calculation，and the control of roll forming machine. The Taguchi method with L18(21X37) orthogonal array was adopted to do the process parameter study and the better forming condition design. Calculation model of the neutral line of the sheet metal was established using the V-Bending test and the FEM simulations. The difference of the experimental test and the FEM simulation was 0.87%. The confidences of the fitted curves of the neutral lines are more than 98.5%. The designed forming path was verified using CAD simulation. The track of the forming path was in good agreement with the longitudinal profile of the product. The results of the Taguchi method revealed the most significant factors for the flatness of product are the rib height and the curvature of forming path. On the other hand, the most significant factors for the springback control of rib are the number of forming pass and bending radius. The confirmation test of the optimum prediction for flatness was 1.56mm which has 7.1% variation compares to the FEM simulation. The confirmation test of the optimum prediction for springback control was 1.6 degrees which has 1.6% variation compares to the FEM simulation.

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27

(10723848), Dan Feng. "MECHANICS, VIBRATIONS, AND TENSION MEASUREMENT OF THIN WEBS IN ROLL-TO-ROLL MANUFACTURING FOR FLEXIBLE AND PRINTED ELECTRONICS." Thesis, 2021.

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Анотація:

Roll-to-roll processes provide a low-cost and high-throughput scheme for scalable flexible devices manufacturing. Multiple processes are used in roll-to-roll manufacturing, such as functional printing, evaporation/drying, UV curing, hot embossing, laser/heat annealing, laser ablation, plasma/ chemical growth, and sputtering. These processes change the web temperature field and/ or local properties. In addition, residual stresses by the process and web tension can destabilize the process and lead to wrinkling or undesirable performance of the products.

This dissertation investigates three different multi-physics problems relevant to the roll-to-roll processes, which are web thermomechanics, air-coupled web vibrations, and the measuring of nonuniform web tension. First, a mathematical model for predicting the in-plane temperature and heat induced stress distributions in a flexible, axially moving web under arbitrary shape of heat flux is presented. The computational approach is validated on experiments performed on moving paper and PET webs with infrared laser heating source. Second, a closed-form, semi-analytical, universal hydrodynamic functions is developed to accurately predict the lowest symmetric and anti-symmetric transverse frequency responses for any uniaxially tensioned web of arbitrary material and aspect ratio used in roll-to-roll processes with the surrounding air acting as distributed added mass. Experimental validation is carried out by using pointwise laser measurements of acoustically excited webs with different pre-tensions, web materials, and aspect ratios. Finally, we develop and test a non-contact resonance method and a gentle contact stiffness mapping method based on the first principles mechanical models of a tensioned plate to accurately measure the average web tension and its linear variation for a wide range of web properties, web path, web tension, measurement configurations, and environmental conditions. The two methods are cross-validated on a stationary test stand and the non-contact resonance method is used to study the web tension distribution within a commercial roll-to-roll system.

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28

Tsao, Chih-pin, and 曹志平. "DESING AND FABRICATION OF A FLEXIBLE LIGHT GUIDE PLATE BY ROLL PROCESS." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/04946931328548489834.

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Анотація:

碩士
大同大學
機械工程學系(所)
99
In recent years, it makes emphasis on flexible displays, such as: electronic paper (E-Paper), but when you want to show the display screen must be light, so this study Backlight unit of the light principle, applied to electronic paper, the image presented. LGP (Light guide plate) has been very widely used in optical display related products, LGP made of non-Flexible in PMMA. Therefore, this study has put forward a highly flexible, high light transmittance of the thermoplastic polyurethane (Thermoplastic Polyurethane; TPU) polymer material to do the study of soft light guide material. And to rolling (Rolling) continuous production methods to produce LGP, this method can accelerate the speed of production and mass production, can effectively lower the cost of production. Produced by the LGP rolling production, the transfer rate can be 87%, the use of BM-7 optical measurement system for measuring the soft LGP, when the flat uniformity of up to 80%. LGP bending 15-degree the light decline rate was only 20%. Therefore, this study successfully used to produce flexible displays of the light guide.

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29

Lin, Yu-Kai, and 林鈺凱. "Flexible roll forming machine design for structural parts with variable profile sections." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/vxt725.

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Анотація:

碩士
國立高雄應用科技大學
模具工程系
104
Flexible roll forming is able to make products with variable width in the longitudinal direction instead of fixed section profile products made by conventional roll forming process. This paper surveyed the exist patents of flexible roll forming machines and proposed a design around machine design. The design methods of the major mechanisms and structures of a flexible roll forming machine was established. A U-shaped product with variable width in the longitudinal direction was adopted to demonstrate the forming path design of the flexible roll forming process. The maximum loads of each station were obtained via the FEM simulation. The dimensions of structure components and the specifications of the motion units were determined using the established design method. The results of forming simulation showed the springback angles varied with respect to the different section locations. The compensation must be made to get the product satisfy with the requirement of geometry precision. The Solidworks software was adopted to analyze the motion path of the designed roll forming machine. The exported path of the roll motion was in good agreement with the profile variation of the product. This verification showed the feasibility of the proposed machine design method. The flexible roll forming machine was designed and built according to the calculation of component strength using the forming loads of the process simulations. The experiment tests of the one station machine showed the forming path design and the motion control model were as good as respect.

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30

Cantrill, David Lee. "Static Pressure Loss in 12”, 14”, and 16” Non-metallic Flexible Duct." Thesis, 2013. http://hdl.handle.net/1969.1/151218.

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This study was conducted to determine the effects of compression on pressure drops in non-metallic flexible duct. Duct sizes of 12”, 14” and 16” diameters were tested at a five different compression ratios (maximum stretch, 4%, 15%, 30% and 45%) following the draw through methodology in ASHRAE Standard 120 -1999 – Methods of Testing to Determine Flow Resistance of Air Ducts and Fittings. With the pressure drop data gathered, equations were developed to approximate the pressure loss at a given air flow rate for a given duct size. The data gathered showed general agreement with previous studies showing an increase in compression ratio leads to an increase in static pressure loss through the duct. It was determined that pressure losses for compression ratios greater than 4% were over four times greater than maximum stretched flexible duct of corresponding duct size. The increased static pressure losses can lead to decreased performance in HVAC systems. The findings of this study add to the existing ASHRAE and industry data for flexible duct with varying compression ratios.

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31

JIAN, ZIH-WUN, and 簡子文. "A Simulation Analysis of Aluminum Alloy A6061 on T-section Compression by Roll Forming." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/89965533774288345076.

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Анотація:

碩士
國立高雄應用科技大學
模具工程系
104
For the purpose of simulated the process of plate on T-section compression by roll forming, the finite element software Deform 3D was used. The main selected material was A6061 aluminum which was most usually used for industry, setting up the reduction as fixed 10 percent on the protrusion at middle of the plate, and gradually increased the reduction on the side of plate by 15 percent, 20 percent, 25 percent and 30 percent. By the way of symmetric compression of same rollers radius roll forming when A6061 aluminum was used, investigated the influences during roll forming including the load on roller, width spread ratio and curvature of product by changing up parameters including thickness ratio of plate, gap width ratio of top roller, width of plate and coulomb friction coefficient, then according these results, then comparing with different materials including Brass-CDA-110 and SUS304 stainless steel that had different strength coefficient and hardening exponent. By the way of asymmetric compression of different radius rollers roll forming, investigate the influences during roll forming by changing up diameter ratio of rollers and coulomb friction on the plate contacting both top and bottom rollers. Finally, set reductions of plate fixed on middle for 10 percent and side for 20 percent, and investigated the influences of different coulomb friction coefficient and roller diameter for SUS304 stainless steel plate which had relatively highest strength coefficient and hardening exponent was between A6061 and Brass-CDA-110 on T-section compression by symmetric of same rollers radius roll forming. According to results from simulations of A6061 aluminum on T-section com-pression by symmetric of same rollers radius roll forming, when thickness ratio of plate and gap width ratio of the top roller increases, the curvature of product decreases, when coulomb friction coefficient and width of plate increases, the width spread ratio of product decreases. By the way of asymmetric of different rollers radius roll forming, when roller diameter ratio increased, the curvature of product trended to be flat. According to results from simulations of SUS304 stainless steel on T-section compression by symmetric of same rollers radius roll forming, when smaller diameter of roller was used and decreased coulomb friction coefficient, the product would adhere to bottom roller, even caused damages during the roll forming process.

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32

HSU, WEI-CHUNG, and 許維中. "Flexible roll forming process design and product manufacturability analysis for ultra high strength steel." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ak9c9w.

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Анотація:

碩士
國立高雄應用科技大學
模具工程系
105
This thesis aims at the process design and the manufacturability analysis of the ultra-high strength steel flexible roll forming. The considerations of the manufacturability analysis including the geometry features, dimensions, and precisions of the product, and the established machine configuration. Three-dimensional CAD of the forming machine was created to do the analysis of working volume. FEM simulations were carried out to evaluate the geometry and dimensions of the product, and the forming load. Ultra-high strength materials JAC590R and JSC1180Y were used to do the forming analysis and the experiments. Error control system was established to cope with the machine configuration and the roll design and to improve the accuracy of products. A three-stand flexible roll forming machine was built with 6 degrees of freedom for each stand( 3 degrees of freedom for each roll, including rotation of upper and lower rolls, rotation of the roll support axis, and the linear motion of the roll support base). The accumulated errors for the 150 mm forward and backward linear motion and the 30 degrees clockwise and counter clockwise rotation tests were 0.027 mm and 0.006 degrees, respectively. The experimental results of the car B pillar forming had revealed that changing the configuration of roll arrangement and adding the guiding roll design were able to reduce the Y-direction deflection up to 24.4%, and 97.1% at the areas of the flat web, the web with convex rib, and the web with concave rib, respectively. The error control system was able to reduce the Z-direction forming speed variation up to 2.36%. Under conditions of the same forming rolls, the established flexible roll forming machine was able to make the A-Pillar, the B-Pillar, The anti-collision beam, and the floor panel of car. The forming tests had demonstrated the flexibility of the built roll forming machine.

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33

Chen, Hsin-Wei, and 陳信偉. "Fabrication of Flexible Dye-Sensitized Solar Cells by the Electrophoretic Deposition and Compression Method." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/92304951375239733860.

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博士
國立臺灣大學
化學工程學研究所
101
There are three parts in this dissertation, with particular attention paid to the low-temperature process for the fabrication of the plastic based dye-sensitized solar cells (DSSCs). It is mainly focused on the photoanode, counter electrode, and gel-electrolyte. For the first part, we focus on the fabrication of photoanode on the conductive plastic substrate using commercially available ZnO and TiO2 nanoparticles by the electrophoretic deposition with compression method. We use the sonication to uniformly disperse the commercial ZnO (20 nm) nanoparticles (NPs) in isopropyl alcohol (IPA), followed by electrophoretic deposition (EPD) at a constant voltage. To control the thickness of the film, we control the deposition period during the EPD process. After the EPD process we then use the compression post-treatment to further strengthen the connection among the particles. Besides, we observe the surface difference of the thin film before and after the compression post-treatment by the scanning electron microscope (SEM) and optimize the film thickness, the compression pressure and the UV ozone treatment, finally reaching a photoelectric conversion efficiency of 4%. In most literatures, the photoelectric conversion efficiency of TiO2 based DSSCs is higher than ZnO based; therefore, we further replace the ZnO NPs by commercial TiO2 NPs (P25, 25 nm, Degussa). By using the same fabrication process to prepare TiO2 thin film electrodes, we further exam the relationship between the compressed particles connection and the photoelectric conversion efficiency by using the pulse laser open-circuit voltage (VOC) decay method and the electrochemical impedance spectroscopy (EIS). Finally we reach the photoelectric conversion efficiency of 4.4%. Due to the conductive plastic substrate, all the process must be carried out below 150 oC to prevent the damage or deformation of the substrates. Therefore, we further introduce the metal titanium (Ti) sheets to replace the conductive plastic substrates, and the Ti sheet can endure the high temperature calcination process after the electrophoretic deposition and the compression post-treatment. We further optimize the calcination temperature, and it then further reduce the grain boundaries in the TiO2 film results in increasing the conduction and making the electrons transport more smoothly. In addition, it reduces the reactions of the electrons recombination resulting in increasing the photoelectric conversion efficiency. However, the illumination of the devices should come from the platinum counter electrode (CE) side due to the opacity of the Ti sheets results in the back-illuminated devices. In addition, the conductivity of the Ti is much higher than the conductive plastic; therefore, we also optimize the EPD and explore the mechanism and principle of the EPD process. Finally, we get the photoelectric conversion efficiency of 6.5%. For the second part, we use the synthesized mesoporous titanium dioxide nanoparticles (MTNs) to replace the commercial TiO2 NPs. The MTNs is composed of 20 nm TiO2 NPs and approximately 200 nm in diameter, and it has a large specific surface area with the large particles (> 150 nm) scattering property. Therefore, the MTNs based photoanodes can not only absorb more dye molecules on the TiO2 surface, but it can also enhance the light absorption in the film. Besides, the crystal phase of the MTNs are all anatase and the grain boundaries are less than the commercial TiO2 NPs, which is beneficial for the transportation of the electrons in the TiO2 film resulting in effective increasing the photocurrent density of the devices. Therefore, we fabricate the MTNs based photoanodes by electrophoretic deposition and compression post-treatment technique on the conductive plastic substrate. In addition, we also examine the parameters of EPD, analyzing the devices by EIS and the incident photon to current conversion efficiency (IPCE) at different wavelengths. Finally, we reach the photoelectric conversion efficiency of 5.5%. Since, to further increase the conversion efficiency of the MTNs based DSSCs, we combine the Au NPs with the MTNs (Au@MTNs), and we fabricate the MTNs based photoanodes with different wt% of gold NPs. The Au@MTNs have plasmonic effects due to the nanometer size gold NPs in the MTNs, we further analyze the Au@MTNs based photoanode by UV-vis absorption/reflection spectra and the IPCE of the devices. The photoelectric conversion efficiency of 5.62% is obtained. For the third part, we use the doctor-blade coating technique with the commercial binder-free low temperature sintering TiO2 paste to prepare the plastic based TiO2 photoanodes. In this part, we focus on the silica based gel-electrolyte containing the mesoporous silica nanoparticles (MSNs), as well as the one-dimensional (1D) hollow acicular cobalt sulfide plastic based CEs. For the silica based gel-electrolyte part, we uniformly mix the MSNs with the commonly used organic liquid electrolyte containing iodine redox couples. We use the EIS and the cyclic voltammetry (CV) to analyze the electrolyte, and we also use the UV-Vis reflection spectra and the IPCE to observe the scattering effect of the MSNs in the electrolyte. For the 1D hollow acicular cobalt sulfide plastic based CEs, we use the chemical bath deposition (CBD) with an anion exchanging method to fabricate the CEs. Besides, we use the X-ray deflection spectra (XRD), the photoelectron spectroscopy (XPS), the scanning electron microscopy (SEM) and the tunneling electron microscopy (TEM) to analyze and identify the cobalt sulfide CEs. In addition, we also use the CV and EIS analysis to exam the 1-D hollow acicular cobalt sulfide CEs.

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34

Zhan, Cheng-Shiun, and 詹承勳. "Analysis of Microstructure on Flexible Substrate Produced by Roll-to-Plane Processes with UV Curing." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/21002374133089430199.

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Анотація:

碩士
國立雲林科技大學
光學電子工程研究所
100
In this study, we use a roller mold to imprint different type of microstructure and it will apply in antireflection for solar cell. Firstly, use optical simulation software to design surface structure with triangle array, pyramid array, cylinder array and hemisphere array. Next, simulate the optical performance and choice the suitable pattern for roller mold. Lastly, triangle array was selected to simulate the top angle and depth. Then, the best result of antireflection was got with top angle of 80 degree and structure depth of 29.79μm. A reflective compare with no texture surface was down 3.793%. However the 80 degree triangular structure was the best geometry shape for roll-to-plane processes in micro imprint antireflection structure. The roller mold uses no gap technology for manufacture, so it has many advantages such as continuity, high efficiency and wide area…etc. Anyway, the suitable UV glue and flexible substrate could easy to control the processes parameters. A good and full micro imprint pattern was got after mold release. At last, the replication calculation of imprint products was 91.52% with micro imprint. From the optical simulation and experimental test, the fabrication of the technology of roll-to-plane imprint was workable.

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35

LIANG, CANG-FU, and 梁倉輔. "Preliminary design of flexible roll forming machine and process planning for advanced high strength steel." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/wm6t64.

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Анотація:

碩士
國立高雄應用科技大學
模具工程系
105
Technologies of the flexible roll forming process simulation and the forming machine design were developed and verified using an example of the U-section 1180Y high strength steel product with variable width profile. The flexible roll forming process was developed according to the cross section geometry and the longitudinal profile of the product. The structure and the motion mechanism of the forming machine was designed with three degree of freedom for each roll and controlled using the Ethernet based control system. The flexible roll forming machine was composed of the modules of guiding, forming roll rotation, forming stand rotation and linear motion, and the Ethernet based control system. The roll forming path was designed to cope with the longitudinal profile of the product and checked with the motion simulation of CAD software. The CAE simulation results predicted the maximum dimension deviation 0.93mm occurs at the web of the arc profile segment. The averaged springback angle was 2.74 degrees at the arc profile segment connected to the previous inclined line segment. Side movement of blank was occurred during the forming experiment and resulted in the product profile shift. The maximum deviation of the sideward shift of the blank is 4.04 because of the guiding rolls after the forming stand was not installed in this one-stand forming machine. The blank was not well-controlled at the exit of the forming stand.

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36

Bonaciu, M. "Flexible and Scalable Algorithm/Architecture Platform for MP-SoC Design of High Definition Video Compression Algorithms." Phd thesis, 2006. http://tel.archives-ouvertes.fr/tel-00086779.

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Ces dernières années, la complexité des puces a augmenté exponentiellement. La possibilité d'intégrer plusieurs processeurs sur la même puce représente un gain important, et amène au concept du système multiprocesseur hétérogène sur puce (MP-SoC). Cet aspect a permis d'amplifier de manière significative la puissance de calcule fourni par ce type de puce. Il est même devenu possible d'intégrer des applications complexes sur une seule puce, applications qui nécessitent beaucoup de calculs, de communications et de mémoires. Dans cette catégorie, on peut trouver les applications de traitement vidéo MPEG4. Pour obtenir de bonnes implémentations en termes de performances, (1) un algorithme de l'encodeur MPEG4 flexible a été réalisé, pouvant être facilement adapté pour différents types de paramètres d'algorithme, mais également différents niveaux de parallélisme/pipeline. Puis, (2) une modélisation flexible a été utilisée, pour représenter différents models d'algorithme et d'architecture contenant 2 SMP. Utilisant ces models, (3) une exploration d'algorithme et d'architecture à un haut niveau d'abstraction a été proposé, en vue de trouver les configurations correctes d'algorithme et d'architectures, nécessaires pour différents applications. A partir de ces configurations, (4) un flot automatique d'implémentation d'architectures RTL a été utilisé. En utilisant ces aspects, l'encodeur MPEG4 a été implémenté avec succès dans plusieurs architectures spécifiques MP-SoC au niveau RTL. La même approche a été utilisée pour l'implémentation de l'encodeur MPEG4 sur une architecture quadri-processeurs existante, pour différentes résolutions, frame-rate, bitrates, etc.

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37

Kasaei, Mohammad Mehdi. "Analytical, numerical and experimental investigation of wrinkling in flexible roll forming of variable cross-sectional channel profiles." Doctoral thesis, 2016. http://hdl.handle.net/10316/87757.

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Анотація:

Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeiros
Flexible roll forming is an advanced sheet metal forming process for cost-effective innovative manufacturing of 3D profiles for automotive lightweight structures. In contrast to roll forming, the flexible roll forming process employs rolls that are not fixed in their position and can be moved along a path in order to describe the desired bend line of the profile. One of the most important defect in flexible roll forming is wrinkling that leads to an undesirable produc. This research work presents a new understanding on the deformation mechanics of the flexible roll forming and is focused on the occurrence of flange wrinkling. A new analytical-numerical model combining the energy method and the finite element simulation is developed to predict wrinkling. In this model, unlike previous models, the purpose is not the calculation of a critical stress assumed to be uniform over the compressive region, but that is the calculation of a factor to indicate the possibility of wrinkling considering the real distribution of stress in the compressive region. Thus, a wave function is assumed in accordance with the boundary conditions of the region under compression in the finite element simulation and the wrinkling factor is obtained as the ratio of the external work done by the in-plane membrane forces and the internal energy of the buckled sheet at each increment. The wrinkling factor depends on mechanical properties, geometry parameters, and current strain and stress field In this thesis, a new theoretical and experimental methodology based on the utilization of rectangular test specimens loaded in axial compression is developed to determine the wrinkling limit curve in the principal strain space. The wrinkling limit curve is then transformed into the space of effective strain versus stress triaxiality and checked against the finite element–predicted evolutions of effective strain with stress triaxiality of the deformed strip in the flexible roll forming process. Another wrinkling factor is proposed based on the wrinkling limit curve. This factor is defined in ABAQUS software by means of a subroutine and applied to determine the possibility of wrinkling during the simulation. A flexible roll forming setup is designed and built to perform the experiments. This setup has three major parts: Forming stand, Feeding mechanism and Control unit. Forming stand consists of two pairs of rolls that are integrated in a parallel kinematic system that allows following the varying contours of the profiles. The experiments were performed on the flexible roll forming setup and the history of longitudinal strain, the warping defect and the geometry of the variable cross-sectional profiles are measured by strain gauge, dial indicator and 3D scanner, respectively. The experimental observations and measurements give support to the numerical results and show that the proposed wrinkling criteria can correctly predict wrinkling in the flexible roll forming. Two proposed wrinkling criteria are applied to determine effects of the geometric parameters (Flange length, radius of bending line, width of transition zone and thickness) of the variable cross-sectional channel profiles and material properties (yield stress and hardening exponent) on the critical forming angle in the flexible roll forming. The results show that flange length, sheet thickness and yield stress have the greatest influence on the critical forming angle.

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38

Chen, Yu-Wen, and 陳裕紋. "The Properties of Flexible Copper Clad LaminateAfter Thermal Compression Process and Control of Process Capability Index Cpk." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/rnx5dr.

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Анотація:

碩士
國立高雄應用科技大學
機械與精密工程研究所
102
This study After Roll to Roll hot Thermal Compression Process produce for Flexible Copper Clad Laminate and Coverlay. while completing Pre Lamination and Hot Press Lamination process needs and explore the finished influence aspect of different parameters. Process the parameter and process properties and having direct influence to Flexible Copper Clad Laminate in hot pressing condition,etc., for example roll for speed, time, temperature and degree of consistency,etc. that heat is distributed of rolling to press while processing when press and is processed. This experiment sets up the value range of the parameter and processes and looks for the optimization in advance; Go on, heat, preheat gyro wheel at first, it preheat 10~15mins temperature reach, set up the temperature 135℃ promptly behind the time, and is reaching the setting up value, heating and laminating to roll to press from 240 ℃ to 250℃ gyro wheel, and roll and press rotational speed and set up time 1~10rpm, press and shut the pressure as 50~70 kgf/cm2 range. Test Flexible Copper Clad Laminate used makes the feasibility which tests the parameter in experiment, and look for the optimization parameter out with the field mouth law form. Roll in heat after pressing and laminating the experiment to finish, and the sample finished with the parameter of the optimization takes a sample, try one scene of superficial attitudes and observe reliability test of analyzing with properties etc., for example strip the intensity, electricity property, is able to bear experiment test of physical property such as medicine properties, heat-resisting properties, hydroscopicity and just property, can get the structure characteristic experimental result after the whole hot pressing gyro wheel is processed.

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39

(9006635), Debkalpa Goswami. "Design and Manufacturing of Flexible Optical and Mechanical Metamaterials." Thesis, 2020.

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Metamaterials are artificially structured materials which attain their unconventional macroscopic properties from their cellular configuration rather than their constituent chemical composition. The judicious design of this cellular structure opens the possibility to program and control the optical, mechanical, acoustic, or thermal responses of metamaterials. This Ph.D. dissertation focuses on scalable design and manufacturing strategies for optical and mechanical metamaterials.

The fabrication of optical metamaterials still relies heavily on low-throughput process such as electron beam lithography, which is a serial technique. Thus, there is a growing need for the development of high-throughput, parallel processes to make the fabrication of optical metamaterials more accessible and cost-effective. The first part of this dissertation presents a scalable manufacturing method, termed “roll-to-roll laser induced superplasticity” (R2RLIS), for the production of flexible optical metamaterials, specifically metallic near-perfect absorbers. R2RLIS enables the rapid and inexpensive fabrication of ultra-smooth metallic nanostructures over large areas using conventional CO₂ engravers or inexpensive diode lasers. Using low-cost metal/epoxy nanomolds, the minimum feature size obtained by R2RLIS was <40 nm, facilitating the rapid fabrication of flexible near-perfect absorbers at visible frequencies with the capability to wrap around non-planar surfaces.

The existing approaches for designing mechanical metamaterials are mostly ad hoc, and rely heavily on intuition and trial-and-error. A rational and systematic approach to create functional and programmable mechanical metamaterials is therefore desirable to unlock the vast design space of mechanical properties. The second part of this dissertation introduces a systematic, algorithmic design strategy based on Voronoi tessellation to create architected soft machines (ASMs) and twisting mechanical metamaterials (TMMs) with programmable motion and properties. ASMs are a new class of soft machines that benefit from their 3D-architected structure to expand the range of mechanical properties and behaviors achievable by 3D printed soft robots. On tendon-based actuation, ASMs deform according to the topologically encoded buckling of their structure to produce a wide range of motions such as contraction, twisting, bending, and cyclic motion. TMMs are a new class of chiral mechanical metamaterials which exhibit compression-twist coupling, a property absent in isotropic materials. This property manifests macroscopically and is independent of the flexible material chosen to fabricate the TMM. The nature of this compression-twist coupling can be programmed by simply tuning two design parameters, giving access to distinct twisting regimes and tunable onset of auxetic (negative Poisson’s ratio) behavior. Taking a metamaterial approach toward the design of soft machines substantially increases their number of degrees of freedom in deformation, thus blurring the boundary between materials and machines.

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40

Krim, Ahmed Omar Ali. "Comparison of coronal minimum intensity projection CT reconstructions with flexible bronchoscopy for airway compression in children with Lymphobronchial TB." Thesis, 2018. https://hdl.handle.net/10539/25386.

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A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine in Diagnostic Radiology Johannesburg 2017.
INTRODUCTION Tuberculosis (TB) remains one of the most important causes of morbidity and mortality in children in Africa, as well as the rest of the world. Lymphobronchial TB (LBTB) occurs when tuberculous adenopathy affects the airways, either by direct involvement (inflammation and erosion) or by indirect involvement (compression and stenosis). Endobronchial TB (EBTB) is the inflammation of the tracheobronchial tree, which is caused by tuberculosis, and is secondary to the rupture of lymph nodes into the bronchi, or the extension thereof to the peribronchial region, by lymphatic drainage. Identification of airway compromise due to any of these processes can be performed invasively using flexible bronchoscopy or non-invasively with CT scanning, including post processing techniques such as minimum intensity projections (MinIP). AIM This retrospective study aimed to generate standardised coronal minimum intensity projection (MinIP) CT reconstructions, and compare these with fibreoptic bronchoscopy in children with LBTB. METHOD Standardised coronal MinIP reconstructions were performed from CT scans in children with LBTB and the findings of three readers were compared with flexible bronchoscopy (FB), regarding airway abnormalities. Intraluminal lesions, the site of the stenosis, and the degree of stenosis were evaluated. The length of stenosis was evaluated by CT MinIP only, and no comparison to FB has been made. RESULTS 65 children with LBTB met the inclusion criteria (38 males; 58.5% and 27 females; 41.5%), with ages ranging from 2.5 to 144 months. Coronal CT MinIP demonstrated a sensitivity of 96% and specificity of 89% against FB. The most common site of stenosis was the bronchus intermedius (91%), followed by the left main bronchus (85%), the right upper lobe bronchus RUL (66%), and the trachea (60%). Agreement between coronal CT MinIP and FB ranged from 36.9% at the carina to 84.6% at the RLL in normal and abnormal airways. CONCLUSION This study has proven that a standardised coronal CT MinIP reconstruction is useful in demonstrating airway stenosis in children with lymphobronchial TB, with sensitivity of up to 96% and specificity up to 89%. The most common sites of stenosis found by the coronal MinIP CT reconstruction were the BI (91%), followed by the LMB (85%), the RUL (66%), and the trachea (60%). The coronal CT MinIP had additional advantages over FB in that it allowed objective measurement of the diameter of the stenosis, measurement of the length of the stenosis as well as visualisation of the post-stenotic segments of the airways. CT MinIP was also able to provide information about lung parenchymal abnormalities. Standardised coronal MinIP reconstructions are easily performed, as described in our paper, and should be provided with each set of cross sectional MDCT images in children with LBTB. This one single image can provide easily appreciable and useful airway information and additional information not available from FB.
LG2018

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41

Singhal, Shrawan. "Jet and coat of adaptive sustainable thin films." 2012. http://hdl.handle.net/2152/22157.

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Deposition of nanoscale thickness films is ubiquitous in micro- and nano-scale device manufacturing. Current techniques such as spin-coating and chemical vapor deposition are designed to create only uniform thin films, and can be wasteful in material consumption. They lack the ability to adaptively prescribe desired film thickness profiles. This dissertation presents a novel inkjet-based zero-waste polymer deposition process referred to as Jet and Coat of Adaptive Sustainable Thin Films or J-CAST. The core of this process is built on an experimentally validated multi-scale fluid evolution model, based on extensions of lubrication theory. This model involves a nano-scale fluid film sandwiched between two flat plates: a compliant superstrate and a rigid substrate, with spatial topography on both surfaces. Accounting for the flexural elasticity of the compliant superstrate, and describing the temporal evolution of the fluid film in the presence of different boundary conditions reveals that instead of seeking process equilibrium, non-equilibrium transients should be exploited to guide film deposition. This forms the first core concept behind the process. This concept also enables robust full-wafer processes for creation of uniform films as well as nanoscale films with prescribed variation of thickness at mm-scale spatial wavelengths. The use of inkjets enables zero-waste adaptive material deposition with the preferred drop volumes and locations obtained from an inverse optimization formulation. This forms the second core concept behind the process. The optimization is based on the prescribed film thickness profile and typically involves >100,000 integer parameters. Using simplifying approximations for the same, three specific applications have been discussed - gradient surfaces in combinatorial materials science and research, elliptical profiles with ~10km radius of curvature for X-ray nanoscopy applications and polishing of starting wafer surfaces for mitigation of existing nanotopography. In addition, the potential of extending the demonstrated process to high throughput roll-roll systems has also been mentioned by modifying the model to incorporate the compliance of the substrate along with that of the superstrate.
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