303 research outputs found

    Applications

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    Volume 3 describes how resource-aware machine learning methods and techniques are used to successfully solve real-world problems. The book provides numerous specific application examples: in health and medicine for risk modelling, diagnosis, and treatment selection for diseases in electronics, steel production and milling for quality control during manufacturing processes in traffic, logistics for smart cities and for mobile communications

    Chapter 34 - Biocompatibility of nanocellulose: Emerging biomedical applications

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    Nanocellulose already proved to be a highly relevant material for biomedical applications, ensued by its outstanding mechanical properties and, more importantly, its biocompatibility. Nevertheless, despite their previous intensive research, a notable number of emerging applications are still being developed. Interestingly, this drive is not solely based on the nanocellulose features, but also heavily dependent on sustainability. The three core nanocelluloses encompass cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial nanocellulose (BNC). All these different types of nanocellulose display highly interesting biomedical properties per se, after modification and when used in composite formulations. Novel applications that use nanocellulose includewell-known areas, namely, wound dressings, implants, indwelling medical devices, scaffolds, and novel printed scaffolds. Their cytotoxicity and biocompatibility using recent methodologies are thoroughly analyzed to reinforce their near future applicability. By analyzing the pristine core nanocellulose, none display cytotoxicity. However, CNF has the highest potential to fail long-term biocompatibility since it tends to trigger inflammation. On the other hand, neverdried BNC displays a remarkable biocompatibility. Despite this, all nanocelluloses clearly represent a flag bearer of future superior biomaterials, being elite materials in the urgent replacement of our petrochemical dependence

    Thermal-Hydraulics in Nuclear Fusion Technology: R&D and Applications

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    In nuclear fusion technology, thermal-hydraulics is a key discipline employed in the design phase of the systems and components to demonstrate performance, and to ensure the reliability and their efficient and economical operation. ITER is in charge of investigating the transients of the engineering systems; this included safety analysis. The thermal-hydraulics is required for the design and analysis of the cooling and ancillary systems such as the blanket, the divertor, the cryogenic, and the balance of plant systems, as well as the tritium carrier, extraction and recovery systems. This Special Issue collects and documents the recent scientific advancements which include, but are not limited to: thermal-hydraulic analyses of systems and components, including magneto-hydrodynamics; safety investigations of systems and components; numerical models and code development and application; codes coupling methodology; code assessment and validation, including benchmarks; experimental infrastructures design and operation; experimental campaigns and investigations; scaling issue in experiments

    International Workshop on Finite Elements for Microwave Engineering

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    When Courant prepared the text of his 1942 address to the American Mathematical Society for publication, he added a two-page Appendix to illustrate how the variational methods first described by Lord Rayleigh could be put to wider use in potential theory. Choosing piecewise-linear approximants on a set of triangles which he called elements, he dashed off a couple of two-dimensional examples and the finite element method was born. … Finite element activity in electrical engineering began in earnest about 1968-1969. A paper on waveguide analysis was published in Alta Frequenza in early 1969, giving the details of a finite element formulation of the classical hollow waveguide problem. It was followed by a rapid succession of papers on magnetic fields in saturable materials, dielectric loaded waveguides, and other well-known boundary value problems of electromagnetics. … In the decade of the eighties, finite element methods spread quickly. In several technical areas, they assumed a dominant role in field problems. P.P. Silvester, San Miniato (PI), Italy, 1992 Early in the nineties the International Workshop on Finite Elements for Microwave Engineering started. This volume contains the history of the Workshop and the Proceedings of the 13th edition, Florence (Italy), 2016 . The 14th Workshop will be in Cartagena (Colombia), 2018

    Advances in Plasma Processes for Polymers

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    Polymerized nanoparticles and nanofibers can be prepared using various processes, such as chemical synthesis, the electrochemical method, electrospinning, ultrasonic irradiation, hard and soft templates, seeding polymerization, interfacial polymerization, and plasma polymerization. Among these processes, plasma polymerization and aerosol-through-plasma (A-T-P) processes have versatile advantages, especially due to them being “dry", for the deposition of plasma polymer films and carbon-based materials with functional properties suitable for a wide range of applications, such as electronic and optical devices, protective coatings, and biomedical materials. Furthermore, it is well known that plasma polymers are highly cross-linked, pinhole free, branched, insoluble, and adhere well to most substrates. In order to synthesize the polymer films using the plasma processes, therefore, it is very important to increase the density and electron temperature of plasma during plasma polymerization

    Aeroelastic instabilities of an airfoil in transitional flow regimes

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    Cette thèse porte sur l'étude de l'instabilité aéroélastique provenant de l'interaction fluide–structure, dans le cas d'une aile rigide montée sur un ressort en torsion. L'étude est centrée sur le phénomène de flottement dû à un décollement laminaire, et plus précisément sur les oscillations (en torsion) auto-entretenues détectées expérimentalement pour un profil NACA0012 à faible incidence, dans la gamme de nombre de Reynolds dits transitionnels (Re in [10^4 – 10^5]), caractérisé par un décollement de la couche limite initialement laminaire, suivi d'une transition et d'un rattachement. L'objectif principal de la thèse est d'expliquer ce phénomène en se basant sur des concepts d'instabilité. Pour ce faire, différentes approches numériques ont été conduites: des simulations numériques bidimensionnelles et des simulations numériques tridimensionnelles (DNS). Ces approches ont en suite servi de base à des analyses de stabilité linéaire (LSA) autour d'un champ moyen ou d'un champ périodique (analyse de Floquet). Le deuxième objectif vise à explorer les différents scénarios non linéaires qui apparaissent dans cette gamme de Reynolds. La première partie de la thèse est consacrée à la caractérisation de l'écoulement autour de l'aile pour des angles d'incidence fixes. Des simulations temporelles bidimensionnelles montrent l'apparition d'oscillations à haute fréquence associées au détachement tourbillonnaire en aval du profil à partir de Re = 8000. Une analyse de stabilité hydrodynamique (Floquet) est réalisée pour caractériser la transition vers un écoulement tridimensionnel. Des simulations tridimensionnelles sont ensuite réalisées pour Re = 50000 afin de caractériser l'écoulement instantané et moyenné. L'analyse des forces moyennes exercées sur l'aile à incidence fixe permettent de détecter une rigidité aérodynamique négative (rapport moment-incidence) pour la gamme |alpha| 0°), où des solutions chaotiques et quasi-périodiques coexistent pour les mêmes paramètres structuraux, et évolue vers un scénario où les oscillations se font autour de alpha = 0°. La dernière partie de la thèse essaie d'expliquer la déstabilisation des positions d'équilibre non nulles conduisant à un comportement quasi-périodique à l'aide d'analyses LSA autour des champs moyens et périodiques à incidence fixe. Même si ces analyses sont incapables de prédire un mode propre instable, nous concluons que l'inclusion du terme des contraintes de Reynolds dans la dynamique de perturbation de l'écoulement moyen a un effet important.This thesis investigates aeroelastic instability phenomena arising in coupled fluid–structure interactions, considering the flow around a rigid airfoil mounted on a torsion spring. The focus is on the laminar separation flutter phenomenon, namely a self-sustained pitch oscillation detected experimentally on a NACA0012 airfoil in the transitional Reynolds number regime (Re in [10^4 – 10^5]) at low incidences, characterised by a detachment of an initially laminar boundary layer followed by its transition and subsequent reattachment. The main objective of the thesis is to explain this phenomenon in terms of instability concepts. For this, a combination of numerical approaches involving two- and three-dimensional Navier–Stokes simulations—the latter refereed to as Direct Numerical Simulations (DNS)—along with linear stability analyses (LSA) around a mean flow or a periodic flow (Floquet analysis) is employed. A second objective is to numerically explore the different nonlinear scenarios appearing in the low-to-moderate Reynolds number regime. The first part of the thesis is devoted to the characterisation of the fluid flow around the airfoil considering fixed incidences. Two-dimensional time-marching simulations are first employed, showing the emergence of high-frequency vortex shedding oscillations for Re = 8000. A hydrodynamic stability analysis (Floquet) is then employed to characterise the transition to a three-dimensional flow and DNS is eventually used to characterise both instantaneous and averaged flow quantities at Re = 50000. An analysis of the mean forces exerted on a fixed-incidence wing allows to detect a negative aerodynamic stiffness (torque-to-incidence ratio) in the range |alpha| < 2°, indicating a static instability. The second part of the thesis is devoted to the characterisation of the primary instability of the coupled fluid–structure system using LSA around the mean and periodic flow fields. Considering the symmetrical equilibrium position alpha = 0°, the analysis shows the presence of an unstable static mode, in accordance with the existence of a negative aerodynamic stiffness. In the third part of the thesis, the emergence of self-sustained flutter oscillations is investigated via two-dimensional aeroelastic simulations. The investigation shows that the system first transitions towards a pitch oscillation around the nonsymmetrical equilibrium position (alpha > 0°), with coexistence of chaotic and quasi-periodic solutions for the same structural parameters, and subsequently transitions towards a pitch oscillation around the symmetrical position (alpha = 0°) as the Reynolds number increases. In the last part of the thesis, an attempt is made to explain the destabilisation of the nonsymmetrical equilibrium positions leading to a quasi-periodic behaviour using LSA around the mean and periodic flow fields at fixed incidences. Even if these analyses are unable to predict an unstable eigenmode, we conclude that the inclusion of the Reynolds stress term in the mean flow perturbation dynamics has an important effect

    Organic Conductors

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    This collection of articles focuses on different aspects of the study of organic conductors. Recent progress in both theoretical and experimental studies is covered in this Special Issue. Papers on a wide variety of studies are categorized into representative topics of chemistry and physics. Besides classical studies on the crystalline organic conductors, applied studies on semiconducting thin films and a number of new topics shared with inorganic materials are also discussed

    System- and Data-Driven Methods and Algorithms

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    An increasing complexity of models used to predict real-world systems leads to the need for algorithms to replace complex models with far simpler ones, while preserving the accuracy of the predictions. This two-volume handbook covers methods as well as applications. This first volume focuses on real-time control theory, data assimilation, real-time visualization, high-dimensional state spaces and interaction of different reduction techniques
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