Bibliografias temáticas / Fil flexible

Literatura científica selecionada sobre o tema "Fil flexible"

Autor: Grafiati

Publicado: 20 de julho de 2024

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Artigos de revistas sobre o assunto "Fil flexible"

Garofalo, Emilia, Luciano Di Maio, Paola Scarfato, Fabrizio Di Gregorio e Loredana Incarnato. "Nanotechnology-Based Strategy to Upgrade the Performances of Plastic Flexible Film Waste". Polymers 11, n.º 5 (8 de maio de 2019): 830. http://dx.doi.org/10.3390/polym11050830.

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The aim of this work was to improve the performances of Fil-s (film-small), a recycled material obtained from plastic flexible film waste that is made of polyethylene and a minor amount of polypropylene, with traces of polar contaminants (polyamides, maleic anhydride, etc.). The idea was to upgrade the material’s mechanical properties by applying a nanotechnology-based strategy that takes advantage of the composition of Fil-s. In particular, different amounts of copolyamide (CoPA) and its masterbatch with an organic-modified nanosilicate were melt compounded with Fil-s in a twin-screw extruder. The good affinity between Fil-s and CoPA, proved by means of spectroscopic and rheological analysis, allowed for the obtaining of a well-refined morphology for the neat and hybrid blends. This resulted in very interesting increments of the strain at break, which was particularly impressive (10 times higher) in the case of the blend with the lower amount of copolyamide masterbatch, but without sacrificing the stiffness and strength of Fil-s.

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Altun, Ali Ozhan, Jun-Ho Jeong, Sung-Un Jung, Ki-Don Kim, Dae-Geun Choi, Jun-Hyuk Choi, Jong-Youp Shim, Dong-II Lee e Eung-Sug Lee. "Stamping-Based Planarization of Flexible Substrate for Low-Pressure UV Nanoimprint Lithography". Journal of Nanoscience and Nanotechnology 8, n.º 11 (1 de novembro de 2008): 5673–77. http://dx.doi.org/10.1166/jnn.2008.254.

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Patterning flexible substrates in nano scale is an important and challenging issue in the fabrication of next-generation devices based on a non-silicon substrate. Step and Flash imprint lithography (S-FIL®) which is a room temperature and low pressure process offers several important advantages, such as the use of a smaller and therefore cheaper stamp or the possibility of the overlay imprinting, as a transparent stamp is utilized. However, it is very difficult to perform S-FIL on a flexible substrate successfully due to the high waviness. The waviness of a flexible substrate is not a constant value in contrast to a rigid substrate. It depends on the imprint pressure applied onto the substrate. In this paper, in section two, the effect of the imprint pressure on the waviness of the surface of the flexible substrate is examined. It is proved that the waviness of the surface of the flexible substrate could not be reduced sufficiently to assure a successful imprint at low imprint pressures. In the third section, a method of patterning polymer substrates using ultra-violet nanoimprint lithography (UV-NIL) is presented. The method consists of two stages, stamping-based planarization and S-FIL. In stamping-based planarization, a planarization layer of transparent polymer is formed onto the flexible substrate. Waviness of the blank stamp (in this study, glass wafer) is transferred to the planarization layer. S-FIL is performed with the nanoimprint tool IMPRIO100 directly onto the planarization layer employing a 1 × 1 in.2 quartz stamp. Optical microscope and SEM images of the successfully imprinted patterns were also presented.

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Garofalo, Emilia, Luciano Di Maio, Paola Scarfato, Arianna Pietrosanto, Antonio Protopapa e Loredana Incarnato. "Study on Improving the Processability and Properties of Mixed Polyolefin Post-Consumer Plastics for Piping Applications". Polymers 13, n.º 1 (27 de dezembro de 2020): 71. http://dx.doi.org/10.3390/polym13010071.

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This study focuses on the upgrading strategies to make Fil-s (acronym for film-small), a polyolefin-based material coming from the mechanical recycling of post-consumer flexible packaging, fit for re-use in the piping sector. The effects of washing treatments (at cold and hot conditions) and the addition of an experimental compatibilizer on the chemical-physical properties of Fil-s were first assessed. The measurements of some key properties (density, melt flow index, flexural modulus, yield strength), for both Fil-s as such and the different developed Fil-s based systems, was also conducted in order to evaluate the suitability of this complex and challenging waste stream to replace virgin PE-based pipe and fitting products, in compliance to ASTM D3350 standard. The outcomes of the present work contributed to define a code, for each Fil-s system investigated, useful for identifying the level of their performance in piping applications. All the recyclates were extruded as pipes by using a pilot scale plant, but the process resulted more stable and continuous with the compatibilized Fil-s, as it was deducible from its flow properties. Moreover, the best mechanical performances were exhibited by the hot-washed Fil-s pipes, with an increase in pipe stiffness equal to 65% respect to the unwashed sample.

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Garofalo, Emilia, Luciano Di Maio, Paola Scarfato, Annalisa Apicella, Antonio Protopapa e Loredana Incarnato. "Nanosilicates in Compatibilized Mixed Recycled Polyolefins: Rheological Behavior and Film Production in a Circular Approach". Nanomaterials 11, n.º 8 (20 de agosto de 2021): 2128. http://dx.doi.org/10.3390/nano11082128.

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Currently, plastic packaging represents a global challenge and has become a key point of attention for governments, media and consumers due to the visibility of the waste it generates. Despite their high resource efficiency, the perceived non-recyclability of polymeric films risks precluding them from being a relevant packaging solution in a circular economy approach. In this regard, the aim of this study was to implement a strategy to try closing the loop, via the mechanical recycling of post-consumer flexible packaging of small size (denoted as Fil-s) to obtain new films. In particular, two lots of Fil-s were used, which are PE/PP blends differing for the PP content and the presence of polar contaminants. The suitability for film blowing extrusion of these recycled materials, as such and after the addition of a compatibilizer and/or a lamellar nanosilicate, was evaluated. It was first evidenced that the difficulty of producing blown films with the pristine recycled materials, due to the frequent bubble breakages, occurring even at low draw ratios. Moreover, the shear and extensional rheological behavior of all Fil-s based systems was usefully correlated with their processability features, evidencing the key roles of the nanofiller to stabilize the bubble and of the compatibilizer to ensure a uniform film deformation, avoiding its premature breakage. Even if the adopted upgrading strategies allowed the production of blown films with both types of Fil-s, the different components of the recycled matrices were proven to significantly affect their processability and final film performances.

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Ruzicka-Rossier, Monique. "Le zonage revisité : l’enseignement de Tokyo". Géo-Regards 6, n.º 1 (2013): 133–45. http://dx.doi.org/10.33055/georegards.2013.006.01.133.

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L’apport de l’article est une contribution à la compréhension du zonage, tout particulièrement dans la marge qu’il peut prendre afin de laisser émerger la ville de la proximité. L’observation nous montre un objet souple, flexible et qui s’hybride lorsqu’il se trouve dans des situations autres que celles qui l’ont vu naître. Au fil de ses déplacements à travers le monde, d’abord le zonage s’articule avec l’existant, le transforme, et à son tour se transforme. Le zonage peut aussi produire un urbanisme fait de combinaisons et de fusionnements entre objets, de mobilisations entre acteurs. Au Japon, le zonage participe étonnamment bien à la ville de la proximité.

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Garofalo, Emilia, Leonardo Taurino, Luciano Di Maio, Heinz C. Neitzert e Loredana Incarnato. "Assessment of Melt Compounding with Zeolites as an Effective Deodorization Strategy for Mixed Plastic Wastes and Comparison with Degassing". Polymers 15, n.º 8 (13 de abril de 2023): 1858. http://dx.doi.org/10.3390/polym15081858.

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The emission of off-odors from mechanically recycled plastics severely limits their re-introduction into the market for the production of new objects, for the same use or even for less demanding applications, thus hindering the implementation of an effective circular economy for plastics. The addition of adsorbing agents during the extrusion of polymers represents one of the most promising strategy to reduce the odorous emissions of plastics, due to its characteristics of cost-effectiveness, flexibility and low energy consumption. The novelty of this work lies in the assessment of zeolites as VOC adsorbents during the extrusion of recycled plastics. They appear more suitable than other types of adsorbents, due to their ability to capture and “hold” the adsorbed substances at the high temperatures of the extrusion process. Moreover, the effectiveness of this deodorization strategy was compared with the traditional degassing technique. Two types of mixed polyolefin wastes, coming from completely different collection and recycling processes, were tested: Fil-S (Film-Small), deriving from post-consumer flexible films of small size, and PW (pulper waste), which is the residual plastic waste obtained from the paper recycling process. The melt compounding of the recycled materials with two micrometric zeolites (zeolite 13X and Z310) resulted as more effective in the off-odors removal with respect to degassing. In particular, the highest reduction (−45%) of the Average Odor Intensity (AOI) was measured for both PW/Z310 and Fil-S/13X systems at 4 wt% of the zeolites’ amount, compared with the corresponding untreated recyclates. Finally, by combining degassing and melt compounding with zeolites, the best result was obtained for the composite Fil-S/13X, whose Average Odor Intensity resulted as quite close (+22%) to the one of the virgin LDPE.

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Derrouiche, Ridha. "Supply Chain 4.0: Improving supply chains with analytics and Industry 4.0 technologies, Emel Aktas, Michael Bourlakis, Ioannis Minis, Vasileios Zeimpekis". Revue Française de Gestion Industrielle 36, n.º 1 (25 de abril de 2022): 124–29. http://dx.doi.org/10.53102/2022.36.01.1111.

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Le concept de la Supply Chain 4.0 est en pleine expansion qui se réfère à l’intégration des nouvelles technologies à l’ensemble des acteurs de la Supply Chain avec l’objectif d’intégrer les flux de matières et de données pour obtenir une Supply Chain plus sûre, plus rapide et plus flexible. Cet ouvrage collectif, a un titre attrayant, est entièrement centré sur la Supply Chain 4.0. Le thème est d'une grande actualité. Bien que très intéressé par le sujet, j'ai eu un peu de mal à terminer les 281 pages car les douze chapitres de cet ouvrage manquent d’un fil directeur et la valeur ajoutée est relativement variable d’un chapitre à un autre. Cependant, cet ouvrage apporte un bon éclairage scientifique sur la façon dont certaines technologies de l'Industrie 4.0 peuvent améliorer les Supply Chains.

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Gaillard, A., M. Roché, S. Lerouge, C. Gay, L. Lebon e L. Limat. "Viscoelastic liquid curtains: experimental results on the flow of a falling sheet of polymer solution". Journal of Fluid Mechanics 873 (24 de junho de 2019): 358–409. http://dx.doi.org/10.1017/jfm.2019.389.

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We experimentally investigate the extensional flow of a sheet – or curtain – of viscoelastic liquid falling freely from a slot at constant flow rate under gravity. Extruded liquids are aqueous solutions of flexible polyethylene oxide (PEO) and of semi-rigid partially hydrolysed polyacrylamide (HPAM) with low shear viscosities. Velocimetry measurements reveal that the mean velocity field $U(z)$ (where $z$ is the distance from the slot exit) does not reduce to a free fall. More precisely, we show that the liquid falls initially with sub-gravitational accelerations up to a distance from the slot which scales as $g\unicode[STIX]{x1D70F}_{fil}^{2}$ (where $g$ is gravity and $\unicode[STIX]{x1D70F}_{fil}$ is the extensional relaxation time of the liquid) due to the stretching of polymer molecules. Beyond this elastic length, inertia dominates and the local acceleration reaches the asymptotic free-fall value $g$. The length of the sub-gravitational part of the curtain is shown to be much larger than the equivalent viscous length $((4\unicode[STIX]{x1D702}/\unicode[STIX]{x1D70C})^{2}/g)^{1/3}$ for Newtonian liquids of density $\unicode[STIX]{x1D70C}$ and dynamic viscosity $\unicode[STIX]{x1D702}$ which is usually small compared to the curtain length. By analogy with Newtonian curtains, we show that the velocity field $U(z)$ rescales on a master curve. Besides, the flow is shown to be only weakly affected by the history of polymer deformations in the die upstream of the curtain. Furthermore, investigations on the curtain stability reveal that polymer addition reduces the minimum flow rate required to maintain a continuous sheet of liquid.

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Ladetto, Marco, Simone Ferrero, Ilaria Del Giudice, Sara Galimberti, Valter Gattei, Luigi Marcheselli, Barbara Mantoan et al. "A Comprehensive and Systematic Analysis of Minimal Residual Disease (MRD) Monitoring in Follicular Lymphoma: Results from the Fondazione Italiana Linfomi (FIL) FOLL12 Trial". Blood 138, Supplement 1 (5 de novembro de 2021): 41. http://dx.doi.org/10.1182/blood-2021-146773.

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Abstract Background. Immunochemotherapy is effective in follicular lymphoma (FL), but most patients (pts) eventually relapse. MRD analysis, based on the detection of Bcl-2/IGH rearrangement by highly sensitive PCR-based tools, is effective in identifying pts at risk of relapse [Ladetto Blood 2012; Pott EHA23]. However, several issues are still unresolved, including: i) which is the best tissue source and the most reliable technique; ii) which are the most predictive time points; iii) which is the role of disease kinetics during the long natural history of FL. The FIL FOLL12 prospective, phase III randomized clinical trial (EudraCT: 2012-003170-60) included a systematic MRD analysis on both peripheral blood (PB) and bone marrow (BM) taken at eight different pre-planned time points, by both nested and real time quantitative (RQ)-PCR. Therefore, it allows addressing these unresolved issues. Methods. The FOLL12 compared conventional rituximab maintenance [Salles et al, Lancet 2010] vs a combined PET/MRD response-based post-induction approach in pts with advanced FL after first line chemo-immunotherapy. Clinical results have been already reported [Luminari et al, ICML16]. PB and BM samples were centralized at four Italian Euro-MRD certified laboratories. MRD was assessed with consensus primers on Bcl-2/IGH rearrangements (MBR, mcr and minor rearrangements) by both nested and RQ-PCR at eight time points: baseline, end of induction (EoI) and every six months thereafter till month 36. MRD data were treated as a time-varying covariate and analyzed by means of flexible parametric survival model (Parmar-Royston) with the log cumulative baseline hazard function. MRD data were modeled with restricted cubic spline as function of time. Effect of fixed covariates and landmark analysis were performed with the Cox PH regression. Any estimation was reported with its 95%CI. Results. Overall, 10,702 analytical results were generated, (3,000 for marker screening and 7,702 for MRD). 780 of 786 eligible pts (99%) were screened at baseline for the presence of a molecular marker. 443/780 (57%) had a detectable Bcl-2/IGH rearrangement, as expected. High rates of MRD negativity were observed at EoI, with similar results by both techniques (87% in BM and 95% in PB by nested-PCR, 90% in BM and 95% in PB with RQ-PCR). Overall, the presence of one MRD positive result was associated during the entire follow-up period with an increased risk of relapse in the subsequent six months interval (HR for PFS 2.82, 95% CI 1.84-4.34, p<0.001), independently from randomization arm (heterogenous test for HR in PFS 0.330), treatment received (HR 0.859) and FLIPI-2 (HR 0.302). Most notably, a sharp increase of HR was observed during follow-up, with time points after 6 and particularly after 12 months or later outperforming the earliest evaluation. Interestingly, very similar results were recorded in BM or PB and using nested or RQ-PCR (Figure 1A). Despite inferior performance compared to later timepoints, MRD positivity in BM at EoI was nevertheless predictive of a shorter 4y-PFS (61% vs 75% by nested-PCR and 54% vs 74% by RQ-PCR, p=0.03 and p=0.003, respectively). Moreover, a kinetic analysis showed that pts scoring MRD+ at EoI but converting to MRD- in the following time points showed superimposable outcome to pts persistently MRD- (HR for PFS 0.66, 95% CI 0.24-1.82, p=0.420), while pts scoring MRD- at EoI but then converting to MRD+ showed a worse outcome (HR for PFS 1.75, 95% CI 1.21-2.53, p=0.003) (Figure 1B). Actually, Kaplan Meier landmark analyses stratified by updated MRD results at each punctual timepoint after EoI were overall highly discriminant in terms of PFS, with PB results (Figure 1C) substantially overlapping BM performances from months 12 after EoI (not shown) and thereafter. Conclusions. This comprehensive MRD study in FL clearly indicates that: i) punctual MRD analysis is predictive of poor outcome at multiple pre-planned time points taken over a 36 months period; ii) both nested and RQ-PCR performed adequately, the latter being preferable as broadly used and internationally standardized; iii) BM allows better prediction at the early time points but, starting from month 12 after EoI PB is superimposable to BM, allowing effective and reliable long-term non-invasive MRD monitoring; iv) the high predictive value of punctual time point analysis is further improved by a kinetic approach to the interpretation of MRD results. Figure 1 Figure 1. Disclosures Ladetto: AbbVie, Jazz, Gentili, Incyte, ADC Therapeutics, Acerta, Pfizer: Honoraria; Roche, J&J, Celgene, Novartis, Amgen, Gilead, Beigene, GSK: Honoraria. Ferrero: Servier: Speakers Bureau; EUSA Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Morphosys: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Gilead: Research Funding, Speakers Bureau; Clinigen: Membership on an entity's Board of Directors or advisory committees. Del Giudice: Tolero: Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Membership on an entity's Board of Directors or advisory committees. Galimberti: Incyte: Speakers Bureau; AbbVie, Janssen: Honoraria, Other: Travel grants. Gattei: abbVie: Research Funding; Janssen: Research Funding; Menarini: Research Funding. Mannina: Janssen,Takeda: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees. Falini: Rasna Therapeutics: Honoraria. Luminari: Roche, Celgene, Teva Pharmaceuticals, Gilead Sciences, and Takeda Pharmaceuticals: Honoraria.

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Chen, Wenling, Chao Liu, Yuqi Zou, Zhihe Ren, Yuanzhuo Xiang, Fanchao Meng, Yinsheng Xu et al. "Flexible omnidirectional reflective film for CO2 laser protection". Chinese Optics Letters 21, n.º 2 (2023): 022201. http://dx.doi.org/10.3788/col202321.022201.

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Teses / dissertações sobre o assunto "Fil flexible"

Maso, Marco. "Flexible Cognitive Small-cells for Next Generation Two-tiered Networks". Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422577.

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In the last decade, cellular networks have been characterized by an ever-growing user data demand that pushed for more and more network capacity to be satisfied. This caused increasing capacity shortfall and coverage issues, aggravated by inefficient fixed spectrum management policies and obsolete network structures. The development of new technologies and spectrum management policies is seen as a necessary step to take, in order to cope with these issues. Concerning the latter aspect, a significant research effort has been made since the beginning of the century, to investigate the advantages brought by flexible management paradigms, such as new dynamic spectrum access (DSA) schemes based on cognitive radio (CR). On the other hand, technological advancements have been proposed by new standards for mobile communications as well, to guarantee capacity enhancements over current networks. From a practical point of view, new approaches to network planning have been proposed together with purely technical solutions, to frame next generation cellular networks capable of meeting the identified target performance to satisfy the user data demands. Accordingly, new hierarchical approaches to network planning, where a tier of macro-cell base stations (MBSs) is underlaid with a tier of massively deployed low-power small-cell base stations (SBSs), are seen as promising candidates to achieve this scope. The resulting two-tiered network layout may improve the capacity of current networks in several ways, thanks to a better average link quality between the devices, a more efficient usage of spectrum resources and a potentially higher spatial reuse. In this thesis, we focus on the challenging problem arising when the two tiers share the transmit band, to capitalize on the available spectrum and avoiding possible inefficiencies. In this case, the coexistence of the two tiers is not feasible, if suitable interference management techniques are not designed to mitigate/cancel the mutual interference generated by the active transmitters in the network. This thesis is divided in three main parts, and proposes a rather exhaustive approach to the development of a new DSA technique, to go from the theoretical basis up to a proof-of-concept development. We first analyze a simplified two-tiered network obtained when deploying an SBS within the coverage area of a pre-existing MBS. We impose that the physical layer strategy adopted in the first tier, i.e., orthogonal frequency division multiplexing (OFDM), must be left untouched. The rationale for this is that we aim the guaranteeing a higher compliance of any proposed solution with the legacy single-tier network structure. Accordingly, we propose a novel technology called cognitive interference alignment (CIA), to be adopted uniquely in the second tier, to allow the two tiers to operate side-by-side in a CR setting. Afterwards, we consider a multi-user extension of the two-tiered network, considering the presence of several SBSs in the second tier. We show how the feasibility of the proposed approach can be extended to such scenarios, designing both a centralized and a distributed approach to manage the multi-user interference in the second tier. The performance of both solutions is evaluated for perfect and imperfect channel state information at the transmitter (CSIT) assumptions, and comparisons with state-of-the-art approaches are provided. Practical implementations issues of both solutions are identified, enlightening main features and drawbacks, and discussing possible solutions. In the last part of the thesis, we gradually take a step forward from the theoretical basis provided in the first two parts, up to a proof-of-concept development of a hybrid transceiver based on the proposed solution. Specifically, we show how the applicability of CIA is not limited to CR settings, and propose an application of this technique to enhance the energy efficiency of a standalone OFDM femto-cell base station (FBS), typical example of new generation low-power device adopted in heterogeneous network deployments. We investigate the enhancements that can be achieved for different channel conditions and statistics and discuss the impact of the power allocation strategy adopted by the FBS on these results. We finally design a working reconfigurable transceiver based on a software defined radio (SDR) approach, to implement devices capable of transmitting/receiving OFDM/CIA signals, or a flexible combination of both. We conclude the thesis by adopting this new tool to validate the theoretical results of the energy efficiency enhancement solution, showing the effectiveness and merit of both CIA and the designed reconfigurable transceiver.
Nell'ultimo decennio, le reti cellulari sono state caratterizzate da una crescita costante della richiesta di dati da parte degli utenti. Unito all'inefficienza delle politiche di gestione dello spettro adottate e all'obsolescenza delle infrastrutture di rete, questo ha generato una crescente necessità di maggiore capacità e copertura di rete. Lo sviluppo di più efficienti politiche di gestione dello spettro radio e di nuove tecnologie è un passo necessario per far fronte a queste problematiche. In questo senso, i vantaggi apportati da nuovi e flessibili schemi di gestione dello spettro, come il cosiddetto dynamic spectrum access (DSA) e gli approcci di tipo cognitive radio (CR), sono stati largamente studiati sin dagli inizi del secolo. Nuove basi per le reti cellulari di prossima generazione sono state poste anche dai più recenti standard, le cui innovazioni tecnologiche promettono un sostanziale aumento di capacità rispetto alle reti esistenti. Oltre alle innovazioni puramente tecniche, le soluzioni proposte per strutturare reti cellulari evolute, in grado di fornire elevate performance e soddisfare le richieste degli utenti, prevedono nuovi paradigmi che ne guidino la progettazione. In questo senso, approcci gerarchici al network planning, risultanti in reti a due livelli, in cui un livello di stazioni di base di tipo macro (MBS) viene affiancato da un livello di stazioni di base di tipo small (SBS), sono considerati estremamente promettenti. Queste nuove reti a due livelli potranno aumentare la capacità delle reti attuali in molti modi, grazie a minori attenuazioni medie nei canali tra i dispositivi, un uso più efficiente della risorsa spettrale e una miglior copertura di rete. Il lavoro presentato in questa tesi è concentrato sulla coesistenza tra i due livelli di rete, quando questi adottano la stessa banda in trasmissione per raggiungere un uso più efficiente della risorsa spettrale. In questo caso, se l'interferenza mutualmente generata dai trasmettitori attivi nei due livelli di rete non viene attenuata o eliminata da adeguati meccanismi per la gestione dell'interferenza, la coesistenza può risultare problematica, quando non impossibile. Questa tesi è suddivisa in tre parti e propone un ampia analisi che porta allo sviluppo di una nuova tecnica di tipo DSA, partendo dalle basi teoriche e arrivando allo sviluppo di un proof-of-concept. Il primo caso studiato è dato da una rete a due livelli semplificata, ottenuta considerando la presenza di una sola SBS all'interno del raggio di copertura di una MBS preesistente. Per garantire la compatibilità delle soluzioni proposte con le operazioni di una classica rete a singolo livello, si impone che la tecnologia di strato fisico adottata dalla MBS, i.e., orthogonal frequency division multiplexing (OFDM), non debba prevedere alcuna modifica. Di conseguenza, le relazioni tra i due livelli di rete vengono strutturate secondo il modello CR, e viene proposta una nuova tecnica per realizzare la coesistenza dei due livelli chiamata cognitive interference alignment (CIA), adottata unicamente dalla SBS. In seguito, l'analisi viene estesa ad una rete multi-utente, considerando la presenza di più di una SBS all'interno del raggio di copertura della MBS preesistente. La fattibilità e l'efficacia di CIA viene analizzata in questo contesto. Di conseguenza, vengono proposte strategie centralizzate e distribuite per la gestione dell'interferenza multi-utente, causata dalla presenza di più SBS all'interno del secondo livello di rete. L'analisi delle prestazioni della rete a due livelli viene effettuata per entrambi gli approcci, in caso di disponibilità di stime di canale al trasmettitore sia perfette sia imperfette (perfect e imperfect CSIT). Questa parte si conclude identificando le problematiche e i meriti principali legati all'implementazione pratica degli approcci proposti, sia centralizzati che distribuiti, e discutendone possibili soluzioni. Nell'ultima parte della tesi, l'analisi si sposta gradualmente da un approccio di tipo teorico ad uno di tipo pratico, portando allo sviluppo di un transceiver ibrido basato sulla tecnica proposta in precedenza, come proof-of-concept. Particolare attenzione viene dedicata nel mostrare come CIA sia applicabile non solo in caso di scenari di tipo CR, ma possa anche essere utilizzata in modo flessibile per incrementare le prestazioni di una generica stazione di base di tipo femto (FBS) utilizzante OFDM, tipico esempio di dispositivo a bassa potenza adottato nelle attuali reti a più livelli. Viene mostrato come un aumento dell'efficienza energetica del dispositivo sia possibile, grazie all'utilizzo di CIA. Inoltre, viene studiato l'impatto dell'allocazione di potenza effettuata dalla FBS su questo risultato viene studiato, considerando la presenza di canali caratterizzati da varie descrizioni statistiche. La tesi si conclude con la progettazione di un transceiver riconfigurabile, realizzato utilizzando un approccio di tipo software defined radio (SDR), al fine di ottenere uno strumento flessibile per realizzare esperimenti pratici che possano convalidare i precedenti risultati teorici. L'architettura proposta, in grado di trasmettere/ricevere segnali di tipo OFDM/CIA (o combinazioni di entrambi), viene infine utilizzata per testare l'efficacia di CIA nell'aumentare l'efficienza energetica di una classica trasmissione OFDM, con risultati positivi.

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Rabobason, Yvon Georges. "Modélisation de système antennaire flexible à bas coût pour objets communicants non planaire". Rouen, 2016. http://www.theses.fr/2016ROUES060.

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L’électronique flexible est actuellement considérée comme une des solutions technologiques face aux contraintes géométriques, baisse de coût et aux exigences technologiques. Cette émergence devra à terme alimenter le marché des vêtements connectés ou l’électronique implantée (in-body electronics). Toutefois, la technologie flexible n’est pas à maturité et présente quelques questions qui restent à soulever comme le choix de substrats à la fois efficace, respectueux de l’environnement et à moindre coûts, la modélisation (numérique ou analytique) d’un système ou sous-système flexible, ou l’analyse des phénomènes Electromagnétiques liés à la forme géométrique non planaire. Ce manuscrit présente le mémoire de mes travaux de thèse qui s’articulent sur la modélisation de système antennaire flexible à bas coût pour objets communicants non planaires. Le premier chapitre introduit les différents paramètres comme le facteur de qualité, les efficacités, le gain ou la polarisation, permettant d’évaluer les performances d’une antenne. Par la suite, des travaux sur différentes structures antennaires, qui se distinguent par l’emploi de substrats flexibles sont présentés et discutés afin de correctement choisir la structure antennaire la plus adéquate aux systèmes flexibles. Ce chapitre se termine par la caractérisation des substrats plastiques souples communément utilisés et qui a vu notre choix s’orienter vers les substrats Kapton HN, qui présentent le meilleur compromis efficacité-coût-robustesse. Les phénomènes EM associés à l’utilisation d’une structure d’antenne patch flexible sont analysés. Des nouvelles formules pour évaluer l’efficacité de rayonnement selon des scénarios de courbures distincts sont établies. Une méthodologie permettant une approche d’analyse et de modélisation des réseaux d’antennes patch 1×2 passif et actif est développée. En dernier lieu, deux nouvelles structures d’antennes souples et performantes en termes de bande passante et efficacités de rayonnement, sont proposées, étudiées et comparées. L’influence de la courbure de ces antennes large bande ont été étudiées en fonction d’un modèle de canal de propagation indoor. L’effet combiné du canal et de la courbure sur le gain effectif moyen des antennes est analysé et discuté
Flexible electronics is currently considered as one of the technological solutions to face up to geometric constraints, lower cost and technological requirements. This emergence will ultimately drive the market for connected clothing, implanted electronics (in-body electronics). However, the flexible technology is not mature and has some issues that remain to lift as the choice of substrates both effective, environmentally friendly and at lower costs, modeling (analytic or digital) of a system or flexible subsystem, or the analysis of electromagnetic phenomena related to non-planar geometry. This manuscript presents the memory of my PhD thesis that focuses on the modeling of flexible antenna system for low-cost non-planar communicating objects. First, the different parameters such as the quality factor, antenna efficiencies, gain or bias, for evaluating the performance of an antenna are introduced. Subsequently, research work on flexible substrate based different antenna structures is presented. The main characteristics of flexible plastic substrates commonly used are addressed. The choice towards the substrates Kapton HN, as the best compromise cost-effectiveness robustness is justified. The influence of the antenna curvature constitutes the main object of the present PhD thesis. In this way, the study on the EM phenomena associated with the use of a flexible patch antenna structure is developed. Novel analytical formulas for assessing the antenna radiation efficiency in discrete curvatures scenarios are established. In addition, a methodology providing an analysis and modeling approach to passive and active 1×2 antenna arrays is presented and validated. Finally, two new structures of flexible high performance antennas in terms of bandwidth and radiation efficiencies are designed and implemented. The Kapton-based broadband structures are based on slots antenna topology with new matching adaptation technique by the use of lumped elements. The influence of the curvature on the slot antenna prototypes are analyzed and discussed

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Maso, Marco. "Flexible Cognitive Small-cells for Next Generation Two-tiered Networks". Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00822415.

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In the last decade, cellular networks have been characterized by an ever-growing user data demand. This caused increasing capacity shortfall and coverage issues, aggravated by inefficient fixed spectrum management policies and obsolete network structures. From a practical point of view, novel technical and architectural solutions have been proposed to frame next generation cellular networks, capable of meeting the identified target performance to satisfy the user data demands. Specifically, new spectrum management policies based on the so-called dynamic spectrum access (DSA), together with hierarchical approaches to network planning, where a tier of macro base stations is underlaid with a tier of massively deployed low-power small base stations, are seen as promising candidates to achieve this scope. The resulting two-tiered network layout may improve the capacity of current networks in several ways, thanks to a better average link quality between the devices, a more efficient usage of spectrum resources and a potentially higher spatial reuse. In this thesis, we focus on the challenging problem arising when the two tiers share the transmit band, to capitalize on the available spectrum and avoid possible inefficiencies. In this case, the coexistence of the two tiers is not feasible, if suitable interference management techniques are not designed to mitigate/cancel the mutual interference generated by the active transmitters in the network. This thesis is divided in three main parts, and proposes a rather exhaustive approach to the development of new DSA and interference management techniques, to go from the theoretical basis up to a proof-of-concept development.

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Villemaud, Guillaume. "Les communications multi-* : contribution au développement d'architectures radio flexibles pour les réseaux sans fil hétérogènes". Habilitation à diriger des recherches, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00937469.

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Ce document présente une synthèse de mes activités de recherche au cours des 10 dernières années. Recruté en septembre 2003 au laboratoire CITI, je suis venu renforcer les activités dans le domaine des communications radios, particulièrement de ce qui d'un point de vue réseau est dénommée la couche physique. Ces activités étaient jusqu'alors portées par un unique permanent (J.M. Gorce) et une doctorante. Pour être cohérent et complémentaire, j'ai dû opérer une évolution thématique pour m'intéresser aux aspects de traitement du signal et de modélisation niveau système, plus en amont de mes activités antérieures plus proches de l'électromagnétisme (même si les aspects antennes sont encore au cœur des problématiques). Mon rôle a ensuite évolué par la mise en place d'une plateforme de mesure permettant une meilleure prise en compte et validation globale des chaînes de transmissions. Cette évolution vers une vision plus globale des systèmes de transmissions m'a permis désormais de développer mon propre axe de recherche sur les aspects systèmes RF flexibles au sein du laboratoire, tout en poursuivant de multiples collaborations transverses avec mes collègues sur des aspects de radio logicielle ou encore de modélisation du canal radio.

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Wu, Hankai. "Développement de transducteurs piézo-résistifs sur substrat textile pour caractérisation de flux d'air". Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2024. http://www.theses.fr/2024IMTA0405.

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L’objectif de ce travail est le développement de solution de détection de perte de charge d’un filtre à air qui doit être intégré à celui-ci pour un fonctionnement dans une centrale de traitement d’air (CTA). En effet, la perte de charge des filtres augmente avec la durée d’utilisation, et cette évolution a un impact non négligeable sur la consommation énergétique des ventilateurs de la CTA. Un système de mesure a été développé à partir de capteurs commerciaux connectés à un microcontrôleur, cependant ce système n’est pas perméable au flux d’air. Une solution de détection textile, basée sur le phénomène de la piézo-résistivité a été donc proposée et développée. Le substrat de base textile qui a été choisi est l’élasthanne pour ses propriétés d’élasticité, et sa capacité à se déformer sous faible contrainte. Ce matériau a été fonctionnalisé par deux techniques avec un polymère π conjugué, le poly(3,4-éthylènedioxythiophène), possédant des propriétés semi-conductrices et apportant une conductivité exploitable à un fil textile unitaire sur des longueurs de l’ordre du mètre. Ces fils textiles fonctionnalisés ont été caractérisés mécaniquement, morphologiquement, électriquement et électro-mécaniquement. Les résultats ont montré une affinité de la couche conductrice sur le substrat textile, et des procédés d’entraînement ont été établis afin d’améliorer les réponses électromécaniques pour une élongation de 5%. Pour finir, des tests préliminaires de détection sur une gaine de ventilation à l’échelle du laboratoire et sur une CTA à l’échelle industrielle ont permis de conclure que ces fils pouvaient discriminer des vitesses d’air allant de 1 à 3 m/s
The aim of this work is to develop a pressure drop detecting system, which is to be integrated onto an air filter in an air handling unit (AHU). Indeed, filter pressure drop increases with the duration of use, and theevolution has a significant impact on the energy consumption of AHU. A measurement system has been developed using commercial sensors connected to a microcontroller. But this system is not permeable to airflow. A textile sensing solution, based on the piezoresistive phenomenon, was therefore proposed and developed. The textile substrate chosen was elastane, because of its elasticity and ability to deform under low stress. This material was functionalized by two techniques with a π conjugated polymer, poly(3,4-ethylenedioxythiophene), possessing semiconducting properties and bringing exploitable conductivity to a unitary textile yarn over lengths of the order of a meter. These functionalized textile yarns were characterized mechanically, morphologically, electrically and electromechanically. The results demonstrated the affinity of the conductive layer to the textile substrate, and training procedures were established to improve electromechanical responses at 5% elongation. Finally, preliminary detection tests on a laboratory-scale ventilation duct and on an industrial-scale AHU concluded that these yarns could discriminate air velocities ranging from 1 to 3 m/s

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Santamaria, Luca. "Systèmes d'antennes reconfigurables intégrés dédiés aux réseaux IoT sans fil dynamiques". Thesis, Université Côte d'Azur, 2021. http://www.theses.fr/2021COAZ4103.

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De par les caractéristiques uniques de l'Internet des objets (IoT), telles qu'un volume massif de données, des contraintes de ressources strictes et des niveaux d'activité hétérogènes, les futures infrastructures IoT sans fil doivent intégrer des solutions d'auto-organisation intelligentes pour fonctionner efficacement dans l'environnement IoT dynamique.Dans ce contexte, cette thèse présente le développement de systèmes d'antennes intégrés reconfigurables innovants capables de s'adapter à de tels réseaux IoT sans fil dynamiques et polyvalents.Dans un premier temps, ce manuscrit de thèse traite de la conception d'antennes adaptées à une intégration dans des terminaux IoT lorsque des propriétés de rayonnement spécifiques ou des opérations multi-bandes sont nécessaires. Les structures d'antennes et les techniques d'intégration sont présentées pour les applications IoT à bande unique et multibande. Dans ce cadre, une méthodologie de conception basée sur une antenne à structure unique multi-accès et une antenne à polarisation circulaire omnidirectionnelle miniaturisée pour les applications IoT sont décrites. Ensuite, une approche basée sur les réseaux de neurones pour estimer les performances de petites antennes compte tenu des contraintes pratiques est présentée. Comme preuve de concept, le cas des antennes imprimées intégrées dans des terminaux compacts est étudié.Dans une seconde partie, la thèse porte sur le développement d'antennes reconfigurables compactes et peu gourmandes en énergie. Afin de permettre de nouvelles applications, telles que les communications portables, et d'offrir des performances supérieures dans une variété d'environnements d'intégration, une antenne flexible et reconfigurable est présentée. Pour garantir un fonctionnement fiable, les antennes flexibles doivent en effet conserver des caractéristiques radioélectriques ou de rayonnement approprié et ceci, malgré la modification de leur structure créée par la flexibilité. Le mécanisme de reconfiguration de l'antenne proposée pour les contraintes évoquées permet le décalage de sa résonance, la rendant ainsi capable de maintenir une adaptation d'impédance acceptable sur toute la bande de fonctionnement même lorsqu’elle est repliée.Une antenne compacte reconfigurable à gain et rapport avant/arrière élevés pour le filtrage spatial dans les réseaux IoT est ensuite proposée. Le mécanisme de reconfiguration est basé sur l'utilisation d'un commutateur SP4T à faible pertes d’insertion et à faible résistance, qui peut être contrôlé numériquement par un microcontrôleur, comme l'exigent les applications IoT. Une antenne à réseau parasite, avec faisceau orientable électroniquement (ESPAR, pour electronically steerable parasitic array radiator), à base d’éléments rayonnants de type fentes adaptée aux applications IoT est ensuite présentée. Le travail décrit en profondeur la procédure de conception de l'antenne, en abordant également la mise en œuvre pratique du mécanisme de reconfiguration, et se concentrant sur la réalisation du prototype et sa caractérisation expérimentale.Enfin, une méthodologie de synthèse de réseaux d'antennes parasites est proposée. Cette méthode est basée sur l'utilisation d'un algorithme de type PSO (Particle Swarm Optimizer), qui optimise de manière itérative les impédances complexes des charges connectées sur les éléments parasites jusqu'à ce que le comportement en rayonnement souhaité soit obtenu. Afin d'évaluer la capacité de la méthode à atteindre les objectifs souhaités, la méthodologie est utilisée pour optimiser la directivité, le rapport avant/arrière et le gain d’antennes à réseau parasite compactes destinées aux appareils IoT. Les valeurs des impédances de charge identifiées avec cette approche sont intégrées dans les structures d'antenne pour réaliser le réseau d'antennes parasites. La reconfiguration peut alors être simplement obtenue en réalisant une permutation circulaire des valeurs de la charge sur les éléments parasites
Because of the unique characteristics of the Internet of things (IoT), such as massive volume of data, stringent resource constraints, and heterogeneous activity levels, future wireless IoT infrastructures must integrate smart self-organizing solutions to efficiently operate in the dynamic IoT environment.Within this context, this thesis presents the development of innovative integrated reconfigurable antenna systems capable of adapting to such dynamic and multi-purposed wireless IoT networks.As a first step, the thesis covers the design of antennas suitable for integration in IoT terminals when specific radiation properties or multi-band operations are needed. Both antenna structures and integration techniques are presented for single and multi-band IoT applications. Next, a design methodology based on a multi-access single structure antenna and a miniaturized omnidirectional circularly polarized antenna for IoT applications are presented. Successively, an approach based on Neural Networks (NN) to estimate the performance of small antennas given practical constraints is presented. As proof of concept, the case of printed antennas integrated into compact terminals is considered.In the second part, the thesis focuses on the development of compact and low-power-consuming reconfigurable antennas. In order to enable new applications, such as wearable communications, and to deliver higher performance in a variety of integration environments, a flexible, reconfigurable antenna is presented. To guarantee reliable operation, flexible antennas must maintain proper electrical or radiation characteristics despite the variation of their structure given by the flexibility. Consequently, the reconfiguration mechanism of the proposed antenna allows the shift of the antenna resonance, making the antenna capable of maintaining an acceptable impedance matching over the operating band even when the antenna is folded.A compact high gain and front-to-back ratio pattern reconfigurable antenna for spatial filtering in IoT networks is then proposed. The reconfiguration mechanism is based on the use of a low-insertion, low-on resistance SP4T switch, which can be numerically controlled by a microcontroller, as required by IoT applications. Successively, a slot-based electronically steerable parasitic array radiator (ESPAR) antenna suitable for IoT applications is presented. The work describes in-depth the design procedure of the antenna, addressing the practical implementation of the reconfiguration mechanism, and focusing on the realization of the prototype and its experimental evaluation.Finally, a methodology for synthesizing parasitic antenna arrays is proposed. The method is based on the use of a Particle Swarm Optimizer (PSO), which iteratively optimizes the parasitic element loads until the desired pattern behavior is obtained. In order to assess the method's ability to address the desired goals, the methodology is used to optimize the directivity, the front-to-back ratio, and the gain of compact parasitic array antennas for IoT devices. The impedance loads values identified with this approach are integrated into the antenna structures to realize the parasitic antenna array. Reconfiguration can then simply be obtained by rotating the load's values over the parasitic elements

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Couillet, Romain. "Application of random matrix theory to future wireless flexible networks". Phd thesis, Supélec, 2010. http://tel.archives-ouvertes.fr/tel-00808022.

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Future cognitive radio networks are expected to come as a disruptive technological advance in the currently saturated field of wireless communications. The idea behind cognitive radios is to think of the wireless channels as a pool of communication resources, which can be accessed on-demand by a primary licensed network or opportunistically preempted (or overlaid) by a secondary network with lower access priority. From a physical layer point of view, the primary network is ideally oblivious of the existence of a co-localized secondary networks. The latter are therefore required to autonomously explore the air in search for resource left-overs, and then to optimally exploit the available resource. The exploration and exploitation procedures, which involve multiple interacting agents, are requested to be highly reliable, fast and efficient. The objective of the thesis is to model, analyse and propose computationally efficient and close-to-optimal solutions to the above operations.Regarding the exploration phase, we first resort to the maximum entropy principle to derive communication models with many unknowns, from which we derive the optimal multi-source multi-sensor Neyman-Pearson signal sensing procedure. The latter allows for a secondary network to detect the presence of spectral left-overs. The computational complexity of the optimal approach however calls for simpler techniques, which are recollected and discussed. We then proceed to the extension of the signal sensing approach to the more advanced blind user localization, which provides further valuable information to overlay occupied spectral resources.The second part of the thesis is dedicaded to the exploitation phase, that is, the optimal sharing of available resources. To this end, we derive an (asymptotically accurate) approximated expression for the uplink ergodic sum rate of a multi-antenna multiple-access channel and propose solutions for cognitive radios to adapt rapidly to the evolution of the primary network at a minimum feedback cost for the secondary networks.

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Nohava, Lena. "Concepts for Wearable Technology in MR : Lightweight Flexible Radio Frequency Coils and Optical Wireless Communication Flexible multi-turn multi-gap coaxial RF coils: design concept and implementation for Magnetic Resonance Imaging at 3 and 7 Tesla Perspectives in Wireless Radio Frequency Coil Development for Magnetic Resonance Imaging". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST069.

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Ce projet doctoral a été réalisé au laboratoire BioMaps de l'Université Paris-Saclay et au CMPBME de l'Université Médicale de Vienne. Afin d’améliorer la valeur diagnostique de l'IRM, il est souhaitable de réduire les durées d’acquisition, d’avoir une prise en charge plus efficace des patients et une meilleure qualité des images. Dans ce but, une instrumentation portable avec un matériel optimisé permettrait de réduire le poids, d’augmenter la flexibilité et de transmettre sans fil les signaux RMN, améliorant ainsi la sensibilité, le confort, la sécurité et la facilité d'utilisation de ces dispositifs.Dans ce contexte, nous avons étudié des antennes RF souples à câbles coaxiaux basées sur le principe des résonateurs à lignes à transmission. Ces résonateurs, pouvant posséder plusieurs tours et/ou plusieurs fentes, permettent d'optimiser la taille de l’antenne RF en fonction de l'application visée. Le concept a d'abord été étudiée in silico. De nombreux prototypes ont été construits et leurs performances ont été testées sur table et en IRM à 3 et 7 T. Les antennes coaxiales ont révélé avoir des performances robustes à la déformation, ne dégradent pas le TAS et peuvent améliorer le RSB et l'efficacité de transmission lorsqu'elles sont conformées au relief de la zone imagée. En parallèle, nous avons mené une étude approfondie des technologies de transmission sans fil en IRM. Un premier prototype de communication optique sans fil pour la transmission de données de capteurs de mouvements a été réalisé et testé. Les antennes coaxiales portables que nous avons étudiées offrent une alternative intéressante aux antennes standard en raison de leur faible poids et de leur flexibilité
This PhD thesis work was conducted at the BioMaps laboratory at the Université Paris-Saclay and the Center for Medical Physics and Biomedical Engineering (CMPBME) at the Medical University of Vienna.To improve diagnostic value in MRI, shorter acquisitions, more efficient patient handling and improved image quality are needed. Wearable technology with optimized hardware reduces weight, increases flexibility, and could be wireless, thereby improving sensitivity, comfort, safety, and usability.In this work, flexible self-resonant coaxial transmission line resonators were investigated. Coaxial coils with multiple turns and gaps enable size optimization depending on the target application. The design was first studied in silico. Numerous prototypes were constructed and their performance was tested on the bench and in 3 and 7 T MRI. Coaxial coils were shown to be robust against bending, have no SAR penalty and improve SNR and transmit efficiency when form-fitted.A review of wireless MR, associated hardware developments and data transmission technology is given.An optical wireless communication module for sensor data transmission was demonstrated experimentally.Wearable coaxial coils offer an attractive alternative to standard coils due to low weight and flexibility. With wireless motion sensors diagnostic value in e.g. breast, knee, or cardiac MRI could be increased

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Gueye, Mouhamadou. "Magnetic thin films on flexible substrates : magnetomechanical study by ferromagnetic resonance". Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCD007/document.

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Les films minces déposés sur des substrats flexibles ont été intensivement étudiés ces dernières années en raison de leur nombreuses applications en électronique flexible. Depuis peu, l'électronique flexible est étendu aux matériaux magnétiques conduisant ainsi au domaine émergeant de la magnéto-électronique flexible actuellement à l'avant garde des sujets de recherche de la spintronique. Ce travail de thèse est dédié à l'étude des propriétés magnéto-mécaniques de films minces magnétiques (Ni, NiFe, Co2FeAl, CoFeB, FeCuNbSi) sur des substrats flexibles. Les analyses structurales ont montré que les films de Ni et de CFA sont polycristallins non-texturés ; le CFB est amorphe. Par conséquent, les propriétés élastiques et magnéto-élastiques de ces films sont considérées comme étant isotropes. Une technique basée sur une utilisation conjointe d'essai mécanique, la résonance ferromagnétique (FMR) et la corrélation d'images numériques (CIN) a été développée pour étudier les propriétés magnéto-mécaniques de films minces sur substrats flexibles. A l'aide de cette méthode, il est possible de suivre l'évolution de l'anisotropie résiduelle omniprésente dans les films magnétiques sur substrats flexibles. Cette anisotropie est liée aux propriétés mécaniques contrastées lorsqu'on dépose un film mince rigide (grand module d'Young) sur un substrat flexible (petit module d'Young). L'effet du recuit sur les propriétés élastiques et magnéto-élastiques a été soigneusement étudié dans le film CFB validant ainsi l'intérêt porté à ses alliages pour des applications en spintronique. Enfin, la résonance ferromagnétique est employé en balayage en fréquence pour suivre la variation de la direction de l'aimantation en fonction des déformations induites par l'application de tension électrique sur l'actionneur piézoélectrique. Un retournement de 90° de la direction de l'aimantation dans le film Co2FeAl sur substrat flexible de Kapton® est observé
Thin films deposited on flexible substrates have been widely studied in the last decades due to the numerous applications in flexible electronics. Recently, flexible electronics have been extended to magnetic materials leading to the so-called emerging feld of flexible magnetoelectronics which is actually at the cutting-edge of spintronics research topics.This thesis is devoted to the study magnetomechanical properties of magnetic thin films (Ni, NiFe, Co2FeAl, CoFeB, FeCuNbSi) on flexible substrates. Structural analysis have 130 Abstracts hown that the Ni and CFA films are found to be polycrystalline with no strong preferred orientations ; the CFB film is amorphous. Consequently, the elastic and magnetoelastic properties are isotropic. For the study of the magnetomechanical properties, a set-up based on a jointly use of deformation test (bending or piezoactuation), ferromagnetic resonance (FMR) and digital image correlation (DIC) have been developped. Thanks to this method, it is possible to follow the evolution of the inescapable residual anisotropy encountered in magnetic thin films on flexible substrates under deformation and to determine the effective coefficient of magnetostriction of the films (sometimes unknown).This residual anisotropy is ascribed to contrasted mechanical strength when a sti thin film is deposited on a compliant substrate. The effect of the annealing temperature on the elastic and magnetoelastic have been studied carefully in CFB validating then theinterest on such alloys for spintronics applications. Finally, we have employed FMR inits sweep frequency mode to study the effective evolution of magnetization direction as function of the voltage-induced strains. A 90-degree magnetization rotation in Co2FeAl thin film on Kapton® polyimide substrate is observed

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Zhang, Irene Y. (Irene Yun). "Efficient file distribution in a flexible,wide-area file system". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53188.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 63-65).
WheelFS is a wide-area distributed file system designed to help applications cope with the challenges of sharing data over the wide-area network. A wide range of applications can use WheelFS as a storage layer because applications can control various trade-offs in WheelFS, such as consistency versus availability, using semantic cues. One key feature that many applications require from any storage system is efficient file distribution. The storage system needs to be able to serve files quickly, even large or popular ones, and allow users and applications to quickly browse files. Wide-area links with high latency and low throughput make achieving these goals difficult for most distributed storage systems. This thesis explores using pre fetching, a traditional file system optimization technique, in wide-area file systems for more efficient file distribution. This thesis focuses on Tread, a pref etcher for WheelFS. Tread includes several types of pre fetching to improve the performance of reading files and directories in WheelFS: read-ahead pre fetching, whole file prefetching, directory prefetching and a prefetching optimization for WheelFS's built-in cooperative caching. To makes the best use of scarce wide-area resources, Tread adaptively rate-limits prefetching and gives applications control over what and how prefetching is done using WheelFS's semantic cues. Experiments show that Tread can reduce the time to read a 10MB file in WheelFS by 40% and the time to list a directory with 100 entries by more than 80%.
(cont.) In addition, experiments on Planetlab show that using prefetching with cooperative caching to distribute a 10MB file to 270 clients reduces the average latency for each client to read the file by almost 45%.
by Irene Y. Zhang.
M.Eng.

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Livros sobre o assunto "Fil flexible"

Siegel, Alexander W. Deceit: A flexible distributed file system. Ithaca, NY: Dept. of Computer Science, Cornell University, 1990.

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Skipidarov, Sergey, e Mikhail Nikitin, eds. Thin Film and Flexible Thermoelectric Generators, Devices and Sensors. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45862-1.

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Vidor, Fábio Fedrizzi, Gilson Inácio Wirth e Ulrich Hilleringmann. ZnO Thin-Film Transistors for Cost-Efficient Flexible Electronics. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-72556-7.

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National Bureau of Standards. Flexible disk cartridge labelling and file structure for information interchange. Gaithersburg, MD: U.S. Dept. of Commerce/National Bureau of Standards, 1986.

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Armstrong, Peter. Flexible Rails: Flex 3 on Rails 2. Greenwich, CT: Manning Publishing, 2007.

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Armstrong, Peter. Flexible Rails: Flex 3 on Rails 2. Greenwich, CT: Manning Publishing, 2007.

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Schwanebeck, Wieland. Der flexible Mr. Ripley: Männlichkeit und Hochstapelei in Literatur und Film. Köln: Böhlau Verlag, 2014.

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F, Hepp Aloysius, e NASA Glenn Research Center, eds. Multi-junction thin-film solar cells on flexible substrates for space power. Cleveland, Ohio: National Aeronautics and Space Administration, Glenn Research Center, 2002.

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Capítulos de livros sobre o assunto "Fil flexible"

Reese, Matthew O., e Teresa M. Barnes. "Flexible Glass in Thin Film Photovoltaics". In Flexible Glass, 211–46. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781118946404.ch7.

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Zhang, Ye, Lie Wang, Yang Zhao e Huisheng Peng. "Flexible Thin-Film Lithium-Ion Batteries". In Flexible Batteries, 9–37. Boca Raton: CRC Press, 2022. http://dx.doi.org/10.1201/9781003273677-2.

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Erlat, Ahmet Gün, Min Yan e Anil R. Duggal. "Substrates and Thin-Film Barrier Technology for Flexible Electronics". In Flexible Electronics, 413–49. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-74363-9_13.

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Junghähnel, Manuela, e John Fahlteich. "Thin-Film Deposition on Flexible Glass by Plasma Processes". In Flexible Glass, 129–79. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781118946404.ch5.

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Huang, YongAn, YeWang Su e Shan Jiang. "Buckling of Film-on-Substrate System in Flexible Electronics". In Flexible Electronics, 27–56. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-6623-1_2.

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McDonald, Paul. "Flexible Stardom". In A Companion to American Indie Film, 493–520. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781118758359.ch22.

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Sazonov, Andrei, Denis Striakhilev e Arokia Nathan. "Low-temperature Amorphous and Nanocrystalline Silicon Materials and Thin-film Transistors". In Flexible Electronics, 53–73. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-74363-9_3.

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Gleskova, Helena, I.-Chun Cheng, Sigurd Wagner e Zhigang Suo. "Mechanical Theory of the Film-on-Substrate-Foil Structure: Curvature and Overlay Alignment in Amorphous Silicon Thin-Film Devices Fabricated on Free-Standing Foil Substrates". In Flexible Electronics, 29–51. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-74363-9_2.

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Hecht, David, e George Grüner. "Solution Cast Films of Carbon Nanotubes for Transparent Conductors and Thin Film Transistors". In Flexible Electronics, 297–328. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-74363-9_10.

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Takenobu, Taishi. "Carbon Nanotube Thin-Film Transistors". In Large Area and Flexible Electronics, 117–32. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2015. http://dx.doi.org/10.1002/9783527679973.ch3.

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Trabalhos de conferências sobre o assunto "Fil flexible"

Rovati, Luigi, Stefano Cattini, Paola Fabbri e Luca Ferrari. "Fluorescence pH Sensor Based on Polymer Film". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8583976.

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Li, Ling. "Surface Potential Based Compact Model for Thin Film Transistor". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8583907.

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Hasan, Md Mehedi, e Jin Jang. "Highly Robust Oxide Thin Film Transistors for Stretchable Electronics". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8583949.

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Kong, Sungwon, Heetaek Lim, Andreas Hoessinger e Eric Guichard. "Mechanical Stress Simulation of Thin Film Transistor on Flexible Substrate". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8583964.

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Myny, Kris. "Flexible Internet-of-Things Circuits Based on Thin-Film Transistors". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8584024.

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Lee, Yongwoo, Jimin Kwon, Woojo Kim e Sungjune Jung. "Flexible Printed Top-Contact Organic Thin-Film Transistors". In 2019 IEEE International Flexible Electronics Technology Conference (IFETC). IEEE, 2019. http://dx.doi.org/10.1109/ifetc46817.2019.9073708.

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Lanthaler, Albert Heinrich, Federica Catania, Hugo De Souza Oliveira, Carlos Beltrami, Alejandro Carrasco-Pena, Michael Haller, Niko Münzenrieder e Giuseppe Cantarella. "Thin-Film Temperature Sensor on Flexible PEEK Fabric". In 2023 IEEE International Flexible Electronics Technology Conference (IFETC). IEEE, 2023. http://dx.doi.org/10.1109/ifetc57334.2023.10254939.

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Cantarella, Giuseppe, Federica Catania, Dianne Corsino e Niko Münzenrieder. "Unobtrusive Thin-Film Devices and Sustainable Green Electronics". In 2023 IEEE International Flexible Electronics Technology Conference (IFETC). IEEE, 2023. http://dx.doi.org/10.1109/ifetc57334.2023.10254853.

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Sappati, Kiran Kumar, e Sharmistha Bhadra. "0–3 Polymer/Barium Titanate Nano Structures Based Flexible Piezoelectric Film". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8583922.

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Tokito, Shizuo. "Flexible Printed Organic Thin-Film Transistor Devices and Integrated Circuit Applications". In 2018 International Flexible Electronics Technology Conference (IFETC). IEEE, 2018. http://dx.doi.org/10.1109/ifetc.2018.8583876.

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Relatórios de organizações sobre o assunto "Fil flexible"

Halevy, B., e T. Haynes. Parallel NFS (pNFS) Flexible File Layout. RFC Editor, agosto de 2018. http://dx.doi.org/10.17487/rfc8435.

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Siegel, Alex, Kenneth Birman e Keith Marzullo. Deceit: A Flexible Distributed File System. Fort Belvoir, VA: Defense Technical Information Center, dezembro de 1989. http://dx.doi.org/10.21236/ada215937.

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Siegel, Alex, Kenneth Birman e Keith Marzullo. Deceit: A Flexible Distributed File System. Fort Belvoir, VA: Defense Technical Information Center, novembro de 1989. http://dx.doi.org/10.21236/ada218620.

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Dean, David M. Flexible Ultra Moisture Barrier Film for Thin-Film Photovoltaic Applications. Office of Scientific and Technical Information (OSTI), outubro de 2012. http://dx.doi.org/10.2172/1057661.

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Kumar, Puneet, e Mahadev Satyanarayanan. Flexible and Safe Resolution of File Conflicts,. Fort Belvoir, VA: Defense Technical Information Center, novembro de 1994. http://dx.doi.org/10.21236/ada289342.

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Culik, J. S., J. A. Rand, Y. Bai, J. R. Bower, J. R. Cummings, I. Goncharovsky, R. Jonczyk, P. E. Sims, R. B. Hall e A. M. Barnett. Silicon-Film{trademark} Solar Cells by a Flexible Manufacturing System. Office of Scientific and Technical Information (OSTI), setembro de 1999. http://dx.doi.org/10.2172/12181.

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Funkenbusch, Arnie, e Charles Ruth. Ultra Barrier Topsheet Film for Flexible Photovoltaics with 3M Company. Office of Scientific and Technical Information (OSTI), dezembro de 2014. http://dx.doi.org/10.2172/1166732.

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Westgate, Sr, e Charles R. Thin Film Photovoltaic Cells on Flexible Substrates Integrated with Energy Storage. Fort Belvoir, VA: Defense Technical Information Center, julho de 2012. http://dx.doi.org/10.21236/ada563841.

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Gursul, Ismet. Interaction of Vortex Breakdown with a Flexible Fin and its Control. Fort Belvoir, VA: Defense Technical Information Center, fevereiro de 2001. http://dx.doi.org/10.21236/ada387213.

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Forrest, Stephen R. Inverted Organic Photovoltaic Cells on Lightweight, and Flexible Metal Foil Substrates. Fort Belvoir, VA: Defense Technical Information Center, março de 2011. http://dx.doi.org/10.21236/ada546867.

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