Tesis sobre el tema "Active interface"
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Powell, Andrew. "On the active guidance of railway vehicles". Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/27142.
Texto completoGruner, Leopold Joachim. "Directed Interface Modifications by Genetically Engineered Surface Active Proteins". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-101569.
Texto completoBaltra, Guillermo P. "Efficient strategies for active interface-level network topology discovery". Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37583.
Texto completoAs a piece of critical infrastructure, the Internet brings both benefits and security concerns. Recent cyber-security episodes such as route hijacks and Denial-of-Service attacks might have been mitigated and prevented with better knowledge of the network_s logical topology; i.e., router nodes and links. Current production public active mapping systems; e.g., Ark, Rocketfuel, and iPlane, produce valuable inferences of the Internet_s topology, as well as facilitating longitudinal analysis. We examine the extent to which the techniques utilized by these existing systems can be improved, in particular by attempting to reduce their high probing load. Our methodology divides the discovery process into three steps: destination selection, monitor assignment, and stop criterion. We implement and evaluate alternative designs for each step. The complete system runs in real-time on a production system to probe 500 randomly selected Internet subnetworks and gather real-world network maps. As compared to datasets from existing measurement platforms, we find that our method is able to generate 80% of the amount of data with 69% less load.
Wahlgren, Marie. "Adsorption of proteins and interactions with surfactants at the solid/liquid interface". [Lund : Dept. of Food Technology, Lund University], 1992. http://books.google.com/books?id=zfxqAAAAMAAJ.
Texto completoGupta, Vaibhav. "A Characterization of Wireless Network Interface Card Active Scanning Algorithms". Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/cs_theses/28.
Texto completoCiobanu, Florentin. "Determination of electrically active traps at the interface of SiC-MIS capacitors". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=977929485.
Texto completoLiu, Chunlei. "Characterisation and modelling of interface reactions between diamond and active brazing alloys /". Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17469.
Texto completoPossinger, Christopher P. (Christopher Paul). "Design of a hand-held user interface for the active joint brace". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32929.
Texto completo"May 2005." Vita.
Includes bibliographical references (p. 23).
The continued development of the Active Joint Brace, a powered orthosis, required that a suitable user interface be designed to control the brace. Since the brace is an electronically-controlled mechanical, medical device, it was important that the user interface (UI) provide both a proper interface to the software that controls the brace, and be in conformance with human factors data. The constraints provided by the existing electronics and software of the brace, combined with suitable ergonomic data, were used to inform the design of a hand-held user interface device, pictured below. The UI features one-handed operation, utilizing an LCD character display and speaker for output devices and a navigation switch for an input device. In preparation for the new UI, the existing menu system was also reorganized for ease-of-use. In preliminary user testing within the development team, the UI has been judged as satisfactory, with only a few minor changes needed to the enclosure.
by Christopher P. Possinger.
S.B.
Kadem, Burak Yahya. "P3HT:PCBM-based organic solar cells : optimisation of active layer nanostructure and interface properties". Thesis, Sheffield Hallam University, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713504.
Texto completoHowar, Falk M. [Verfasser], Bernhard [Akademischer Betreuer] Steffen y Karl [Akademischer Betreuer] Meinke. "Active learning of interface programs / Falk M. Howar. Betreuer: Bernhard Steffen. Gutachter: Karl Meinke". Dortmund : Universitätsbibliothek Dortmund, 2012. http://d-nb.info/1099294959/34.
Texto completoHowar, Falk [Verfasser], Bernhard [Akademischer Betreuer] Steffen y Karl [Akademischer Betreuer] Meinke. "Active learning of interface programs / Falk M. Howar. Betreuer: Bernhard Steffen. Gutachter: Karl Meinke". Dortmund : Universitätsbibliothek Dortmund, 2012. http://nbn-resolving.de/urn:nbn:de:101:1-201605033153.
Texto completoDa, Rocha Sandro Roberto Possatti. "CO₂-water interface : interfacial tension, emulsions, microemulsions, and computer simulations /". Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004246.
Texto completoBlom, Annabelle. "Structure and physical properties of surfactant and mixed surfactant films at the solid-liquid interface". Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/649.
Texto completoBlom, Annabelle. "Structure and physical properties of surfactant and mixed surfactant films at the solid-liquid interface". University of Sydney. Chemistry, 2005. http://hdl.handle.net/2123/649.
Texto completoSuryatriyastuti, Maria Elizabeth. "Numerical study of the thermo-active piles behavior in cohesionless soils". Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10055/document.
Texto completoThe recent technology for the heating/cooling building system, known as thermo-active piles, has effectively reduced the land use area and drilling cost by incorporating the vertical closed-loop heat exchanger pipes into the pile foundations. The heat transfer principle remains the same with the conventional ground heat exchanger system: an extraction of the steady ground temperature during winter and a recharge of the ground thermal energy during summer. Indeed, the energy transfer in the thermo-active pile system is becoming more complex owing to the thermo-hydro-mechanical interaction between the ground, the aquifer, the concrete pile, and the overlying building. Recently in France, the implementation of this novelty faces some difficulties due to the lack of understanding about the potential impact of seasonal temperature cycles on the environmental sustainability and the structural safety. Considering those concerns, this thesis conducts the study of the thermo-active piles behavior and their interaction with the structure and the environment in the intention to optimize the geotechnical design of such piles according to the French design standard for the deep foundations. First of all, a study of the physical phenomena occurring in the entire system under the thermo-hydro-mechanical interactions is conducted. Since the ratio of the pile diameter and the pile length is very small, the temperature variations in the pile affect mainly the pile axial response. Thus, the study interest is narrowed to the impact of temperature cycles on the pile bearing capacity by paying a particular attention on modeling the soil–structure interaction with finite difference method. A set of three-dimensional numerical models is performed to understand the thermo-active piles response located in cohesionless soil with consideration of several loading stages and various restraint conditions. The first model concerns a single thermo-active pile subjected to a single thermal load, the second deals with a single thermo-active pile under combined axial mechanical and cyclic thermal loads, and the third one is related to the thermo-active piles located in a group of piles to observe the influence on the other classical bearing piles. The need to properly render the cyclic plasticity behavior in such piles is provided by modeling the interface elements at the soil–pile contact zone using the laboratory-developed law named ‘Modjoin’ law. Otherwise, the load transfer t–z method in one-dimensional model can be an alternative solution in the practical geotechnical design, but no t–z law that takes into account the cyclic fatigue effects exists yet. This study carries out a development of the existing t–z law by integrating the nonlinearity condition and cyclic hardening rules
Ramo, Keetjie Joy. "Person-environment interface as \"image\" : a new environmental-active conceptual framework for social work practice /". The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262513407472.
Texto completoHassan, Hassan Athab. "A GAN BASED DUAL ACTIVE BRIDGE CONVERTER TO INTERFACE ENERGY STORAGE SYSTEMS WITH PHOTOVOLTAIC PANELS". Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1512161344172419.
Texto completoDegache, Amelie. "Electrical impedance spectroscopy applied to the chronic monitoring of the fibrosis induced by cardiac active implants". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0432.
Texto completoCardiac arrhythmias represent about 50% of the cardiovascular diseases which are the first cause of mortality in the world. Implantable medical devices play a major role for treating these cardiac arrhythmias. In France, about 250.000 patients are equipped with an implanted device for arrhythmia treatment and need a regular monitoring. These devices use the latest technology of micro-nano-electronics and integrate a subcutaneous pulse generator connected to electrodes placed into the heart via intravenous leads. One of the main weaknesses of every implantable device lies in the electrode-tissue interface due to a sustained inflammatory response called fibrosis. This phenomenon jeopardizes the device biocompatibility, because it encapsulates the stimulation lead with an “insulating” tissue, creating adherences along the lead and often leading to an increase of the stimulation threshold over time and a larger electrical consumption. This response is well-known and minimized during the implantation surgery thanks the use of steroid-elution electrodes, however fibrosis still remains an impediment even for the most recent devices, enhancing the interest of studying long-term biocompatibility of cardiac implanted devices.The understanding of fibrosis mechanisms is essential for this work. It consists in some cardiac cells activation and differentiation under a mechanical stress, inducing fibrosis initiation and modifying locally the active cardiac tissue. To characterize this modification, we use electrical impedance measurements, consisting in sending a sinusoidal electrical current I and then measuring the resulting voltage U in the tissue; the impedance Z is the U/I ratio. Depending on the frequency of the measurement signal, we can explore the tissue from the microscopic to the macroscopic scales. As a patient is already equipped with cardiac leads connected to a stimulation device which can also record the cardiac electrical activity, the main idea of this work is to investigate the use of an electrical measurement that could characterize the fibrotic lead encapsulation, with the final objective to embed this characterization method in the implanted circuit. This brings us to the main question of our project: does the fibrosis developing around the cardiac leads have an electrical signature?My thesis work is organized along three axes. Two experimental axes are conducted at cellular and tissue levels, on in vitro or ex vivo models. In addition, an axis studying the feasibility of embedded impedance measurement for in vivo mimicking conditions is also discussed. The ex vivo part presents the characterization of tissue of different natures, healthy or collagenous, it was developed with the IHU LIRYC laboratory, on porcine or ovine cardiac tissue (ventricles mainly), with stimulation electrodes used on patients The impedance spectra are analyzed using a known electrical model from which characteristic parameters of the two tissue types are extracted. After statistical analysis, these parameters are found to be significantly different allowing us to distinguish both tissue types. The in vitro part presents the electrical characterization, using impedance measurements, in parallel to the biological characterization, using immunocytochemistry, of a cellular fibrosis model. It consists in culturing human cardiac cells, activated or not by a growth factor. After a statistical analysis, the impedance values show a significantly different signature for cultures with growth factor, with respect to sham cultures, while the biological characterization confirmed the presence of more activated and differentiated cells over time. The last axis gives preliminary results of embedded impedance measurements in custom circuits
Krinninger, Philip [Verfasser] y Matthias [Akademischer Betreuer] Schmidt. "Effective Equilibrium, Power Functional, and Interface Structure for Phase-Separating Active Brownian Particles / Philip Krinninger ; Betreuer: Matthias Schmidt". Bayreuth : Universität Bayreuth, 2019. http://d-nb.info/1177143070/34.
Texto completoGruner, Leopold Joachim [Verfasser], Gerhard [Akademischer Betreuer] Rödel y Malte [Gutachter] Gather. "Directed Interface Modifications by Genetically Engineered Surface Active Proteins / Leopold Joachim Gruner ; Gutachter: Malte Gather ; Betreuer: Gerhard Rödel". Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/1150309350/34.
Texto completoWang, Xiaolu. "Janus Colloids Surfing at the Surface of Water". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS272/document.
Texto completoAt the single-particle level, the main difference between active colloids and passive ones is the time scale over which the motion crosses over from ballistic to diffusive regime. In both cases, friction coefficients or equivalently diffusion coefficients determine this time scale. For instance, the motion of a passive colloid of 1m radius is diffusive when observed over lag times longer than a microsecond, once the direction of its momentum has been randomized by collisions with solvent molecules. At the macroscopic scale these collisions are accounted for by the translational friction coefficient. For an active colloid the effective diffusive behavior observed over lag times larger than few seconds results from the randomization of the direction of self-propulsion by rotational diffusion. In this thesis we investigated the motion of an active Janus colloid trapped at air-water interface. Spherical catalytic Janus colloids have been prepared through the deposition of platinum metal at the surface of silica particles. Immersion depth of the Janus colloid as well as their orientation with respect to the water surface, has been characterized and interpreted in terms of the non-uniform wetting properties of the Janus particles. The motion of the active Janus colloids in the presence of various concentration of hydrogen peroxide H2O2 as fuel was characterized by video microscopy and the trajectories analyzed through the mean square displacement and the velocity autocorrelation function. The types of trajectories, directional and circular ones that we observed in our experiments, revealed the effective force and torque induced by the catalytic decomposition of H2O2. At the water surface, active colloids perform more persistent directional motions as compared to the motions performed in the bulk. This has been interpreted as due to the loss of degrees of freedom resulting from the confinement at interface and also to the partial wetting conditions that possibly bring new contributions to the rotational friction at interface
Sykes, Kayla Paris. "Human Factors Evaluation of an In-Vehicle Active Traffic and Demand Management (ATDM) System". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/65003.
Texto completoMaster of Science
Marth, Wieland. "Hydrodynamic Diffuse Interface Models for Cell Morphology and Motility". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-204651.
Texto completoDiese Dissertation beschäftigt sich mit mathematischen Modellen zur Beschreibung von Gleichgewichts- und dynamischen Zuständen von verallgemeinerten biologischen Zellen. Die Zellen werden dabei als thermodynamisches System aufgefasst, bei dem Strömungseffekte innerhalb und außerhalb der Zelle zusammen mit einem Helfrich-Modell für Zellmembranen kombiniert werden. Schließlich werden durch einen Energie-Variations-Ansatz die Evolutionsgleichungen für die Zelle hergeleitet. Es ergeben sie dabei Mehrphasen-Systeme, die Strömungseffekte mit einem freien Randwertproblem, das zusätzlich physikalischen Einflüssen wie Biegung und Oberflächenspannung unterliegt, vereinen. Um solche Probleme effizient zu lösen, wird in dieser Arbeit die Diffuse-Interface-Methode verwendet. Ein Vorteil dieser Methode ist, dass es sehr einfach möglich ist, Modelle, die verschiedenste Prozesse beschreiben, miteinander zu vereinen. Dies erlaubt es, komplexe biologische Phänomene, wie zum Beispiel Zellmotilität oder auch die kollektive Bewegung von Zellen, zu beschreiben. In den Modellen für Zellmotilität wird ein biologisches Netzwerk-Modell für GTPasen oder auch ein Active-Polar-Gel-Modell, das die Aktinfilamente im Inneren der Zellen als Flüssigkristall auffasst, mit dem Multi-Phasen-Modell kombiniert. Beide Modelle erlauben es, komplexe Vorgänge bei der selbst hervorgerufenen Bewegung von Zellen, wie das Vorantreiben der Zellmembran durch Aktinpolymerisierung oder auch die Kontraktionsbewegung des Zellkörpers durch kontraktile Spannungen innerhalb des Zytoskelets der Zelle, zu verstehen. Weiterhin ist die kollektive Bewegung von vielen Zellen von großem Interesse, da sich hier viele nichtlineare Phänomene zeigen. Um das Diffuse-Interface-Modell für eine Zelle auf die Beschreibung mehrerer Zellen zu übertragen, werden mehrere Phasenfelder eingeführt, die die Zellen jeweils kennzeichnen. Schließlich werden die Zellen durch ein lokales Abstoßungspotential gekoppelt. Das Modell wird angewendet, um White blood cell margination, das die Annäherung von Leukozyten an die Blutgefäßwand bezeichnet, zu verstehen. Dieser Prozess wird dabei bestimmt durch den komplexen Zusammenhang zwischen Kollisionen, den jeweiligen mechanischen Eigenschaften der Zellen, sowie deren Auftriebskraft innerhalb der Adern. Die Simulationen zeigen, dass diese Annäherung sich in bestimmten Gebieten des kardiovaskulären Systems stark vermindert, in denen die Blutströmung das Stokes-Regime verlässt. Schließlich wird das Active-Polar-Gel-Modell mit dem Modell für die kollektive Bewegung vom Zellen kombiniert. Dies macht es möglich, die kollektive Bewegung der Zellen und den Einfluss von Hydrodynamik auf diese Bewegung zu untersuchen. Es zeigt sich dabei, dass der Zustand der kollektiven gerichteten Bewegung sich spontan aus der Neuausrichtung der jeweiligen Zellen durch inelastische Kollisionen ergibt. Obwohl die Hydrodynamik einen großen Einfluss auf solche Systeme hat, deuten die Simulationen nicht daraufhin, dass Hydrodynamik die kollektive Bewegung vollständig unterdrückt. Weiterhin wird in dieser Arbeit gezeigt, wie die stark gekoppelten Systeme numerisch gelöst werden können mit Hilfe der Finiten-Elemente-Methode und wie die Effizienz der Methode gesteigert werden kann durch die Anwendung von Operator-Splitting-Techniken und Problemparallelisierung mittels OPENMP
MANCA, NICOLO'. "Functional modelling and prototyping of electronic integrated kinetic energy harvesters". Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2675157.
Texto completoKwak, Sangshin. "Design and analysis of modern three-phase AC/AC power converters for AC drives and utility interface". Texas A&M University, 2005. http://hdl.handle.net/1969.1/2336.
Texto completoLargeot, Céline. "Développement de supercondensateurs carbone/carbone : relation entre la taille des ions de l'électrolyte et la taille des pores de la matière active". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/529/.
Texto completoThe aim of this work is to study ion/porous carbon interactions in supercapacitor electrodes to improve their electrochemical performances. Titanium Carbide Derived Carbon (TiC-CDC) are microporous carbon with monodisperse porosity. They allowed us to finely study the interactions between electrolyte's ion size and active material pore size during the electrochemical double layer formation in two different kind of electrolyte (organic and ionic liquid). Unlike to traditional views, in order to maximise capacitance, carbon pore size must be close to electrolyte ions size. It was demonstrated that ions adsorbed on carbon's surface are at least partially desolvated. As carbon porosity is well adapted to electrolyte ions size, the capacity is improved of 40 % in acetonitrile and 60 % in ionic liquid. This corresponds respectively to an enhancement by two and by three of the energy of supercapacitors
Castagnola, Valentina. "Implantable microelectrodes on soft substrate with nanostructured active surface for stimulation and recording of brain activities". Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2646/.
Texto completoImplantable neural prosthetics devices offer, nowadays, a promising opportunity for the restoration of lost functions in patients affected by brain or spinal cord injury, by providing the brain with a non-muscular channel able to link machines to the nervous system. The long term reliability of these devices constituted by implantable electrodes has emerged as a crucial factor in view of the application in the "brain-machine interface" domain. However, current electrodes for recording or stimulation still fail within months or even weeks. This lack of long-term reliability, mainly related to the chronic foreign body reaction, is induced, at the beginning, by insertion trauma, and then exacerbated as a result of mechanical mismatch between the electrode and the tissue during brain motion. All these inflammatory factors lead, over the time, to the encapsulation of the electrode by an insulating layer of reactive cells thus impacting the quality of the interface between the implanted device and the brain tissue. To overcome this phenomenon, both the biocompatibility of materials and processes, and the mechanical properties of the electrodes have to be considered. During this PhD, we have addressed both issues by developing a simple process to fabricate soft implantable devices fully made of parylene. The resulting flexible electrodes are fully biocompatible and more compliant with the brain tissue thus limiting the inflammatory reaction during brain motions. Once the fabrication process has been completed, our study has been focused on the device performances and stability. The use of high density micrometer electrodes with a diameter ranging from 10 to 50 µm, on one hand, provides more localized recordings and allows converting a series of electrophysiological signals into, for instance, a movement command. On the other hand, as the electrode dimensions decrease, the impedance increases affecting the quality of signal recordings. Here, an organic conductive polymer, the poly(3,4-ethylenedioxythiophene), PEDOT, has been used to improve the recording characteristics of small electrodes. PEDOT was deposited on electrode surfaces by electrochemical deposition with a high reproducibility. Homogeneous coatings with a high electrical conductivity were obtained using various electrochemical routes. Thanks to the increase of the surface to volume ratio provided by the PEDOT coating, a significant lowering of the electrode impedance (up to 3 orders of magnitude) has been obtained over a wide range of frequencies. Thermal accelerated ageing tests were also performed without any significant impact on the electrical properties demonstrating the stability of the PEDOT coatings over several months. The resulting devices, made of parylene with a PEDOT coating on the active surface of electrodes, have been tested in vitro and in vivo in mice brain. An improved signal to noise ratio during neural recording has been measured in comparison to results obtained with commercially available electrodes. In conclusion, the technology described here, combining long-term stability and low impedance, make these implantable electrodes suitable candidates for the development of chronic neural interfaces
Minotto, Alessandro. "Characterization of CdSe-CdxZn1-xS core-shell QDs as active materials for compact micro-cavity lasers". Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3424089.
Texto completoIl progresso in svariati settori tecnologici, a partire dai dispositivi emettitori di luce, passando per le aree delle telecomunicazioni e delle energie rinnovabili, fino alla diagnostica medica e alla terapia, è favorito dalla ricerca e dallo sviluppo nel campo della nanofotonica. Tra le diverse classi di nanomateriali che stanno contribuendo a questo avanzamento, i nanocristalli di materiale semiconduttore, alias Quantum Dots (QDs) o Punti Quantici, presentano le proprietà ottiche più versatili. I QDs sono nanostrutture inorganiche di materiale semiconduttore le cui eccezionali prestazioni in termini di emissione di luce li rendono diretti concorrenti dei materiali a stato solido più "convenzionali" in molte applicazioni commerciali. L'interesse a sviluppare dispositivi basati su QDs si è diffuso su larga scala con lo sviluppo di metodi di sintesi di tipo colloidale. L'approccio colloidale facilita la processabilità e l'integrazione in dispositivi emittitori di luce con dimensioni che vanno dal micron a pochi nanometri. In particolare, i QDs colloidali si prestano alla realizzazione di sorgenti laser a stato solido compatte e su substrati flessibili. Le proprietà ottiche dei QDs sono regolate dal confinamento quantistico (QC). Questo regime si instaura quando la dimensioni del materiale sono comparabili con il raggio eccitonico di Bohr. Il QC, in quanto effetto di taglia, rende le proprietà di assorbimento e di emissione di luce dipendenti dalle dimensioni. Grazie al QC, i QDs possiedono livelli elettronici ben definiti e interagiscono con la luce in maniera simile ai sistemi molecolari. Allo stesso tempo, i QDs dimostrano elevate sezioni d’urto di assorbimento e stabilità al danneggiamento, proprietà tipiche dei semiconduttori inorganici. Questo lavoro di tesi è incentrato su una classe emergente di QDs colloidali, ossia QDs “core-shell” composti da CdSe-CdXZn1-XS, aventi cioè un nucleo (“core”) di CdSe, ricoperto da un guscio (“shell”) di CdXZn1-XS. L'attenzione è focalizzata principalmente sulle proprietà di guadagno ottico il quale rappresenta per i QDs una delle applicazioni più promettenti e maggiormente studiate. Attraverso la caratterizzazione dell'Emissione Spontanea Amplificata (ASE) di diverse serie di QDs di CdSe-CdXZn1-XS, questo lavoro dimostra che proprietà chiave come la soglia di attivazione ASE, nonché la stabilità all’irragiamento, possono essere ottimizzate mediante un’attenta progettazione dell’eterostruttura core-shell. Mediante diverse tecniche di spettrocopia ottica è possibile ricavare alcune linee guida per la sintesi di QDs con proprietà di guadagno ottico ottimali. Con queste tecniche è quindi possibile identificare la correlazione tra le dinamiche di eccitazione/rilassamento e la composizione, spessore e, in ultima analisi, struttura del materiale di shell. Parametri di base come le dimensioni medie dei QDs, la dispersione di taglia e la resa quantica di luminescenza (QY) possono essere facilmente estratti dalle tecniche di assorbimento ed emissione in stato stazionario. Queste ultime sono state impiegate come strumenti preliminari per dimostrare che, variando la composizione e lo spessore del guscio esterno di CdXZn1-XS, si altera il grado di confinamento degli eccitoni nel nucleo di CdSe, la dispersione in dimensioni e la QY. In una seconda fase, la tecnica SERS (Surface-Enhanced Raman Scattering o Scattering Raman amplificato da superfici) è stata impiegata per la prima volta come sonda locale per lo studio dell’interfaccia tra core e shell. La tecnica SERS permette la caratterizzazione dei nanocristalli nelle stesse condizioni strutturali e di dinamica reticolare presenti nei QDs quando impiegati come mezzi attivi in dispositivi fotonici. I risultati di questo studio hanno rivelato che la composizione del guscio di CdXZn1-XS comporta delle significative differenze strutturali all'interfaccia core-shell. Questa variazione strutturale modifica la struttura elettronica nei QDs in quanto influenza il grado di confinamento degli elettroni e delle lacune nel core. L'effetto dell'interfaccia core-shell sulle proprietà ottiche è stato inequivocabilmente rilevato mediante l'uso di tecniche di spettroscopia ottica transiente. In particolare, in questo lavoro di tesi sono stati studiati sia l’assorbimento transiente (TA) sia la luminescenza transiente (tPL) ai fini di esaminare le dinamiche di generazione e di ricombinazione degli eccitoni. L’evoluzione della densità eccitonica è stata quindi confrontata con dei modelli cinetici. A differenza delle tecniche a regime stazionario, le tecniche transienti sono sensibili alla natura e ai tempi caratteristici relativi ai diversi percorsi di rilassamento, radiativi e non radiativi, il cui controllo è fondamentale ai fini dell’ingegnerizzazione dell’eterostruttura. I parametri cinetici ottenuti hanno rivelato una chiara dipendenza dall'interfaccia core-shell e la correlazione con i risultati ottenuti mediante SERS sono stati discussi. La correlazione tra struttura e dinamica è stata rilevata a partire dalla scala temporale del nanosecondo (tPL) fino alla scala dei picosecondi (TA). Uno scopo secondario di questa tesi è anche quello di elaborare un'interpretazione globale delle dinamiche di tutti i segnali presenti negli spettri transienti per diverse serie di QDs CdSe-CdXZn1-XS. La densità di eccitazione, lo spessore del guscio e la sua composizione sono le coordinate lungo le quali si è sviluppata tale analisi globale. Questo passo è di cruciale importanza ai fini di identificare i parametri legati al processo di guadagno ottico, i cui tempi caratteristici in sistemi a base di QDs variano dai picosecondi fino a pochi nanosecondi. Dalla discussione dei risultati ottenuti dalle diverse tecniche di caratterizzazione, emerge che il modo più efficace per aumentare le proprietà ottiche dei QDs di CdSe è la realizzazione di un guscio CdXZn1-XS a composizione graduale, in cui la concentrazione di Zn (e di conseguenza il potenziale di confinamento) aumenta gradualmente lungo la direzione radiale. In una sola entità, questa soluzione è in grado di fornire un adeguato confinamento dei portatori di carica dalla superficie esterna, limitare la formazione di difetti all'interfaccia e infine ridurre le dimensioni globali dei QDs. La minimizzazione delle dimensioni permette di aumentare la densità d’impaccamento e limita le perdite dovute allo scattering quando i QDs sono inclusi in una matrice solida e/o depositati come film sottile. Tali aspetti sono di fondamentale importanza ai fini di migliorare l’efficienza di un amplificatore ottico a quantum dots. Infine, la validità delle ipotesi formulate è stata verificata sperimentalmente caratterizzando la ricombinazione radiativa bi-eccitonica, la quale rappresenta l’origine fotofisica dell’ASE e quindi definisce le prestazioni di guadagno ottico delle diverse nano-eterostrutture opportunamente ingegnerizzate. Come previsto, dalle misure di ASE le migliori performance dal punto di vista del guadagno ottico sono state raggiunte utilizzando QDs di CdSe ricoperti con uno shell a composizione graduata di CdS-Cd0.5Zn0.5S-ZnS. I risultati ottenuti mediante la caratterizzazione spettroscopica forniscono dunque una linea guida per la progettazione di nuove strategie di sintesi che siano orientate alla preparazione di QDs altamente foto-stabili e con una soglia di attivazione ASE minimale. In aggiunta, la razionalizzazione delle dinamiche coinvolte nella generazione e ricombinazione eccitonica e multi-eccitonica in QDs core-shell può accelerare la loro applicazione in tutti i tipi di dispositivi emettitori di luce.
Humphreys, Heather Celeste. "Modeling and compensation for biodynamic feedthrough in backhoe operation". Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37254.
Texto completoSavioli, Livia /. LS. "Analysis of innovative scenarios and key technologies to perform active debris removal with satellite modules". Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424289.
Texto completoSarà sicuramente capitato qualche volta di guardare il cielo stellato e di scorgere un piccolo puntino luminoso che si muoveva come un aeroplano, ma senza lampeggiare come di solito fanno le luci degli aerei: si trattava di un satellite. E' sempre affascinante pensare che ci sono oggetti che orbitano continuamente attorno alla Terra, così distanti da noi. Forse, non è così noto che ce ne sono davvero tanti...migliaia...17,000 quelli più vicini alla Terra, per la precisione. E' diffcile immaginare come così tanti oggetti possano orbitare senza toccarsi o scontrarsi tra loro. Fin dall'inizio delle attività spaziali nel 1957, un'enorme quantità di oggetti è stata lanciata o rilasciata in orbita, e pensando che lo spazio sia così illimitato da poter contenere ogni cosa, tutti questi oggetti sono stati abbandonati in orbita. Il risultato è stato la creazione di un gran numero di detriti che hanno iniziato a rappresentare una minaccia per le future missione spaziali. Recenti studi hanno rivelato che se proprie contromisure non saranno adottate per ridurre la creazione di ulteriori detriti in orbita, come per esempio satelliti non operativi e stadi orbitali, l'ambiente spaziale potrebbe rimanere stabile solo per i prossimi 20 o 30 anni. Oltre tale termine, potrebbero verificarsi eventi di collisioni in cascata tra gli oggetti attualmente in orbita causando un rapido aumento del numero di detriti, anche nel caso irrealistico di un completo arresto dei lanci. Questo fenomeno autosostenuto, noto come Sindrome di Kessler, potrebbe impedire qualsiasi altra missione nello spazio. Nonostante a partire dagli anni '90 siano state proposte misure di mitigazione per limitare la generazione di detriti in orbita, esse si sono rivelate insufficienti per garantire una stabilità a lungo termine dell'ambiente spaziale. L'unico modo di intervenire è l'implementazione, in parallelo, di missioni di rimozione attive dei detriti spaziali (in inglese Active Debris Removal - ADR). L'efficacia di tali missioni è stata dimostrata, ma ci sono ancora numerose questioni che devono essere affrontate per poterle applicare nella realtà. Da un lato, l'efficienza dei possibili scenari di missione deve essere investigata in modo da individuare le soluzioni migliori. Dall'altro lato ci sono ancora diverse questioni tecnologiche particolarmente critiche, specialmente riguardo la cattura dei detriti, che sono essenzialmente oggetti non cooperativi e quindi non predisposti per essere catturati. La ricerca sviluppata nel presente lavoro di tesi è stata focalizzata su due degli aspetti principali legati all'ADR: I) analisi di missione di ADR e II) sviluppo di una tecnologia chiave per l'ADR; nel caso specifico, di un'interfaccia deformabile adesiva per la cattura di oggetti non-cooperativi. E stato considerato uno scenario di missione basato sull'impiego di veicoli distinti per l'esecuzione dei trasferimenti orbitali e delle manovre di de-orbiting. In particolare, un veicolo di grandi dimensioni per i primi e propri kits di de-orbiting per le seconde. La soluzione innovativa sviluppata è stata l'adozione di strutture modulari per la realizzazione dei kits di de-orbiting: esse consistono nell'assemblare un certo numero di unità base di microsatelliti, equipaggiate con specifici sistemi di de-orbiting; il numero di unità assemblate dipende dalle caratteristiche del detrito, in termini di massa e altezza iniziale, e dalla particolare tecnologia di de-orbiting. Uno scenario di questo tipo comporta una maggiore efficienza, adattabilità e flessibilità. Sono inoltre previsti vantaggi in termini di costo e di massa, con la possibilità di impiegare economie di scala grazie alla standardizzazione delle unità impiegate. Nello studio sono state considerate quattro soluzioni di de-orbiting: vele per l'aumento del drag, propulsione elettrica, filo elettrodinamico (electrodynamic tether) e propulsione ibrida. Diversi scenari di missione sono stati analizzati per determinare le caratteristiche delle soluzioni adottate, in termini di massa del sistema di de-orbiting e di tempo totale di manovra. Per ogni tecnologia è stata dimensionata una unità microsatellite elementare. Inoltre, è stata anche implementata una procedure di ottimizzazione di trasferimenti orbitali multipli per minimizzare la massa del sistema propulsive richiesto. Sono state poi individuate cinque bande orbitali in cui attuare l'ADR, caratterizzate da detriti con masse tra 800 kg e 11 tonnellate, e altezze tra gli 800 km e i 1000 km. Le analisi hanno rivelato che le vele per incrementare il drag atmosferico, pur essendo soluzioni a basso costo e semplici, non sono adeguate per la rimozione di detriti massivi in orbite elevate perchè richiederebbero dimensioni troppo elevate con un aumento della possibilità di collisioni durante la fase di de-orbiting. La propulsione elettrica e il filo elettrodinamico sono entrambe soluzioni promettenti per l'ADR: per detriti con massa minore di 2000 kg le due tecnologie sono comparabili, sia in termini di massa del sistema di rimozione, sia di tempo di de-orbiting. Per detriti più massivi, con massa maggiore di 2000 kg, il filo elettrodinamico è più vantaggioso in termini di massa, ma richiede tempi di de-orbiting molto maggiori rispetto alla propulsione elettrica. La probabilità di avere impatti con detriti fino a 10 cm di diametro è risultata maggiore del limite suggerito nel NASA-STD-8719.14 di 0.001. Nel caso della propulsione elettrica invece, si è ottenuto un rischio di collisioni catastrofiche trascurabile. La propulsione ibrida è risultata la soluzione più svantaggiosa in termini di massa, ma è quella che consente il de-orbiting in tempi più ridotti. La seconda parte dell'attività di ricerca è focalizzata sullo sviluppo di un'interfaccia deformabile adesive che potrebbe essere impiegata come end-effector di un meccanismo robotico per la cattura di oggetti non-cooperativi. Due diverse tecnologie sono state considerate per lo studio: polimeri a memorie di forma, per la capacità di adattarsi a forme differenti, e l'elettroadesione per l'adesione mediante forze elettrostatiche. Due prototipi sono stati realizzati e testati. Dai test è emerso che sia un precarico meccanico che le forze elettrostatiche contribuiscono ad aumentare l'adesione. Si sono ottenuti livelli di pressione normale di adesione dell'ordine di 0.55 kPa - 1.4 kPa senza forze elettrostatiche, con variazione del precarico meccanico tra 1.5N e 10 N. L'adesione aumenta in presenza di forze elettrostatiche, variando tra 1.4 kPa e 1.8 kPa per diverse condizioni di precarico meccanico e voltaggio applicato per generare le forze elettrostatiche. Le forze di adesione ottenute variano tra 3.5 N e 11.5 N. Sono stati eseguiti anche dei test che prevedevano la deformazione del supporto per vericare la capacità di deformazione e adesione in presenza di irregolarità macroscopiche sulla superficie dell'oggetto da catturare. Tali test hanno dimostrato che la presenza di un supporto polimerico tipo schiuma può essere vantaggioso nel caso di cattura di oggetti irregolari, in quanto consente di adeguarsi alla forma della superficie dell'oggetto e aderire anche in presenza di irregolarità. In questo modo l'efficacia della soluzione proposta è stata confermata.
Taylor, Jennyfer Lawrence. "Ngana Wubulku Junkurr-Jiku Balkaway-Ka: The intergenerational co-design of a tangible technology to keep active use of the Kuku Yalanji Aboriginal language strong". Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/206447/1/Jennyfer_Taylor_Thesis.pdf.
Texto completoArrotéia, Aline Valverde. "Gestão do projeto e sua interface com o canteiro de obras sob a ótica da preparação da execução de obras (PEO)". Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3299.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
During the last twenty years the construction field in Brazil has evolved significantly in response to its market growing and competitiveness. However this evolving path has faced many obstacles such as cultural barriers and the lack of efforts to achieve quality at the Brazilian construction site. As one of the causes of this facts the lack of integration between construction and the designing process generates waste, pathologies, work redone and improvised changes originated by incompatible projects which were taken by incapacitated personnel at an inconvenient moment. At the same time, the great amount of information generated on the designing or construction phases is lost due to the lack of an effective coordination of these activities. From this scenario Souza (2001), has developed two management methods in her doctorate thesis named Preparation for the Execution of Buildings (known as PEO) and the Pro-active Coordination (known as CPA), these methods are based on the application of the processes adopted by the French construction industry on Brazilian construction sites. These methodologies aim to establish the integration of the project phases by a set of actions and activities implemented by a system of meetings where the main objective is to discuss the projects and the planning of the construction site seeking to obtain a better quality and better outcome on the productive process. These methodologies aim to bring expressive improvements on the productivity, as well as on the lowering of waste, on the settlement of goals, on planning actions in accordance with all the agents involved and mainly on the reduction of costs allied to higher quality standards. Thus is an objective of this research to implement the Preparation on the Execution of Buildings (PEO) seeking to understand the management of the designing process and its interface with the construction site. The methodology applied on the development of the analysis is classified as qualitative and it will be carried by the practical application of the research and the evaluation of its results. Thus, the study was divided into two stages, one of them intended for a pilot study of PEO in Company A, and the other to the implementation of PEO on the company B. This way, the method was developed from a system meetings entitled structured in three different stages: the release of PEO; the development of PEO and the completion of the intensive phase of PEO, which were performed over a period from two to three months. The data analysis was structured upon five main aspects which were evaluated during the implementation of the method on the studied companies. These aspects were: the actions taken during the PEO phase, the development of the actions and the participation of the agents; the internal structure of the companies analyzed; The management and design coordination and the contract form of the contractors, architects and engineers. The results obtained demonstrated the PEO method's effectiveness and viability while a booster on the improvement of project management. Therefore, it can be concluded that the PEO is feasible to be applied in building construction companies, since this method can contribute to the integration of the design phases and construction, as well as to the improvement of the communication between the agents involved in the building construction field.
Nos últimos 20 anos, o setor da construção civil no Brasil evoluiu significativamente em resposta ao crescimento da competitividade no mercado. Entretanto, nesse processo de evolução ainda têm sido encontradas barreiras culturais e organizacionais, e, sobretudo, dificuldades nos esforços à qualidade nos canteiros de obras brasileiros. Aliada a este quadro, a falta de integração entre as atividades de construir e projetar provoca uma série de desperdícios, patologias, retrabalhos e alterações improvisadas decorrentes de projetos não compatibilizados, ora por ausência de detalhes nos projetos, ora por decisões tomadas por pessoas não capacitadas em momentos inadequados. A partir dessa realidade, Souza (2001) desenvolveu dois métodos de gestão nomeados Preparação da Execução de Obras (PEO) e Coordenação Pró-Ativa (CPA) em sua tese de doutoramento, por meio da transposição desses métodos adotados na gestão da interface projeto-execução de obras na França para a realidade dos canteiros de obras brasileiros. Esses métodos visam à integração das etapas de projeto e obra a partir de um conjunto de ações e atividades realizadas por meio de reuniões sistematizadas voltadas à discussão do projeto, ao planejamento e à organização do futuro canteiro de obras, a fim de obter melhor qualidade e desempenho no processo produtivo. Dessa forma, este trabalho tem como objetivo geral implementar o método da preparação da execução de obras (PEO) a fim de avaliar a interface entre a gestão do processo de projeto e a execução do canteiro de obras. A metodologia adotada para o desenvolvimento deste trabalho é classificada como qualitativa, a qual foi realizada por meio de uma pesquisa-ação, e dividida em duas etapas diferentes, sendo uma destinada ao estudo piloto da PEO na empresa A, e a outra à implementação da PEO na empresa B. Deste modo, a aplicação do método foi desenvolvida a partir de um sistema de reuniões em três fases intituladas: lançamento da PEO; desenvolvimento da PEO e finalização da fase intensiva de PEO, as quais foram realizadas em um período entre dois e três meses. A análise de dados foi estruturada a partir de cinco aspectos principais, os quais foram avaliados durante a aplicação do método nas empresas estudadas, sendo eles: quanto às ações desenvolvidas na fase de PEO, quanto ao desenvolvimento das reuniões e a participação dos agentes; quanto à estrutura organizacional e departamental das empresas; quanto à gestão e a coordenação de projetos; e quanto ao formato de contratação dos projetistas e subempreiteiros. Os resultados obtidos com a realização deste trabalho comprovaram a eficácia do método da PEO e a sua viabilidade enquanto potencializador na melhoria da gestão da interface projeto-execução de obras. Portanto, pode-se concluir que a PEO é viável de ser aplicada em empresas de construção e incorporação de edifícios, uma vez que este método pode contribuir para a integração das etapas de projeto e execução, bem como na melhoria da comunicação e na interação entre os agentes envolvidos na produção de edifícios.
Real, Hernandez Luis M. "Preparation of Non-Surface-Active Solutions from Bovine Milk and Dairy-Based Beverages to Improve Langmuir Trough Model Systems of Dairy Fluids". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534510214734083.
Texto completoPoncin-Epaillard, Fabienne. "Etude de la polymerisation induite par plasma froid : interface plasma-polymere, greffage, degradation et modification chimique". Le Mans, 1987. http://www.theses.fr/1987LEMA1028.
Texto completoWidmark, Jörgen. "Social Agent: Facial Expression Driver for an e-Nose". Thesis, Linköping University, Department of Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1863.
Texto completoThis thesis describes that it is possible to drive synthetic emotions of an interface agent with an electronic nose system developed at AASS. The e-Nose can be used for quality control, and the detected distortion from a known smell sensation prototype is interpreted to a 3D-representation of emotional states, which in turn points to a set of pre-defined muscle contractions. This extension of a rule based motivation system, which we call Facial Expression Driver, is incorporated to a model for sensor fusion with active perception, to provide a general design for a more complex system with additional senses. To be consistent with the biologically inspired sensor fusion model a muscle based animated facial model was chosen as a test bed for the expression of current emotion. The social agent’s facial expressions demonstrate its tolerance to the detected distortion in order to manipulate the user to restore the system to functional balance. Only a few of the known projects use chemically based sensing to drive a face in real-time, whether they are virtual characters or animatronics. This work may inspire a future android implementation of a head with electro active polymers as synthetic facial muscles.
Turgut, Can. "Prise en compte de la liaison acier béton dans le comportement d’éléments de structure en béton armé". Thesis, Paris 10, 2018. http://www.theses.fr/2018PA100170/document.
Texto completoIn numerical applications of reinforced concrete structures, the steel-concrete interface behavior has a vital importance when the cracking properties are investigated. A finite element approach for the steel-concrete interface to be used in large-scale simulations was proposed by (Torre-Casanova, 2013) and (Mang, 2016). It enables to calculate the slip between the steel and concrete in the tangential direction of the interface element representation. The aim is here to improve the initial bond-slip model to be more efficient and more representative. The document is divided into three parts: 1) The existing bond-slip model is evaluated. The bond-slip model is then improved by considering transversal and irreversible bond behaviors under alternative loads. The new bond-slip model is validated with several numerical applications. 2) Confinement effect is implemented in the bond-slip model to capture the effect of external lateral pressure. According to the performed numerical applications, it is demonstrated how the active confinement can play a role, through the steel-concrete bond, during monotonic and cyclic loading cases. 3) Dowel action is finally investigated with the new bond-slip model. Two different experimental campaigns (Push-off tests and four-point bending tests) are reproduced with different reinforcement (1D truss and beam) and interface (new bonds-slip and perfect bond) models. The results show that the proposed simulation strategy including the bond slip model enables to reproduce experimental results by predicting global (force-displacement relation) and local behaviors (crack properties) of the reinforced concrete structures under shear loading better than the perfect bond assumption which is commonly used in the industrial applications
Ranft, Jonas M. "Mechanics of Growing Tissues: A Continuum Description Approach". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105479.
Texto completoDie Entwicklung höherer Organismen beginnt mit einer einzelnen befruchteten Eizelle und endet beim erwachsenen Tier. Die vielen Prozesse, die zur endgültigen Form des entwickelten Organismus führen, werden als Morphogenese zusammengefasst; diese umfasst insbesondere das Wachstum von Geweben durch wiederholte Zellteilungszyklen. Während koordiniertes Gewebewachstum eine Voraussetzung normaler Entwicklung ist, führt übermäßige, unkontrollierte Zellteilung letztlich zu Krebs. In dieser Arbeit untersuchen wir den Einfluss von Zellteilung und Zelltod auf die Organisation von Zellen in Geweben. Die Dynamik wachsender Gewebe wird durch mechanische Bedingungen beeinflusst, die u.a.~Anlass zu Zellbewegungen sein können. Wir entwickeln eine Kontinuumsbeschreibung der Gewebedynamik, die die mechanischen Spannungen und das Zellströmungsfeld auf großen Skalen beschreibt. Zellteilung und Apoptose wirken als Spannungsquellen, die in der Regel anisotrop sind. Indem wir die Erhaltungsgleichung für die Zellanzahldichte mit dynamischen Gleichungen für die Spannungsquellen kombinieren, zeigen wir, dass sich das Gewebe effektiv wie eine viskoelastische Flüssigkeit verhält, deren Relaxationszeit von Zellteilungs- und Apoptose-Raten abhängt. Wenn das Gewebe in einem gegebenen Volumen eingeschlossen ist, erreicht es einen homöostatischen Zustand, in dem Zellteilung und der Apoptose im Gleichgewicht sind. In diesem Zustand unterliegen die Zellen einer diffusiven Bewegung aufgrund der Stochastizität von Zellteilung und Apoptose. Wir berechnen den effektiven Diffusionskoeffizienten als Funktion der Gewebeparameter und vergleichen unsere Ergebnisse sowohl hinsichtlich der Diffusion und als auch der Viskosität mit numerischen Simulationen solcher vielzelliger Systeme. Die Berücksichtigung der extrazellulären Flüssigkeit als einer zweiten Materialkomponente erlaubt uns zu zeigen, dass eine endliche Permeabilität des Gewebes zusätzliche mechanische Effekte bedingt. Auf langer Zeitskalen bleibt die mechanische Reaktion des Gewebes auf externe Störungen auf einen Bereich beschränkt, dessen Größe vom Verhältnis der Gewebeviskosität zum Permeabilitätskoeffizienten abhängt. Die Zweikomponenten-Beschreibung erlaubt darüber hinaus eine klare Unterscheidung der verschiedenen Beiträge zum isotropen Teil der mechanischen Spannung, d.h., des hydrodynamischen und des von Zellen ausgeübten Drucks. Zuletzt untersuchen wir die Dynamik einer Grenzfläche zwischen zwei verschiedenen Zellpopulationen innerhalb eines Gewebes, die durch Unterschiede in der mechanischen Kontrolle der effektiven Zellteilungsraten angetrieben wird. Mithilfe der Kombination einfacher analytischer Grenzfälle und numerischer Simulationen zeigen wir, dass zwei unterschiedliche Ausbreitungsmodi unterschieden werden können: ein diffusives Regime, in dem relative Flüsse die Expansion der stärker wachsenden Zellpopulation dominieren, sowie ein Regime, in dem die Grenzfläche durch konvektive Strömungen angetrieben wird
Les organismes supérieurs se développent à partir d\'une seule cellule fécondée jusqu\'à l\'animal adulte. Les nombreux processus qui conduisent à la forme finale de l\'organisme sont connus sous le nom de morphogenèse, qui comprend notamment la croissance des tissus par des cycles répétés de division cellulaire. Alors que la croissance coordonnée des tissus est une condition nécessaire au développement des animaux, la division cellulaire excessive chez les animaux adultes est l\'ingrédient clé du cancer. Dans cette thèse, nous étudions l\'organisation collective des cellules par division et mort cellulaire. La dynamique multicellulaire des tissus en croissance est influencée par des conditions mécaniques et peut donner lieu à des réarrangements ainsi qu\'à des mouvements cellulaires. Nous élaborons une description continue de la dynamique des tissus qui décrit la distribution des contraintes et le champ d\'écoulement des cellules sur de grandes échelles. La division cellulaire et l\'apoptose introduisent des sources de contraintes qui, en général, sont anisotropes. En combinant l\'équation de conservation du nombre de cellules avec des équations dynamiques des sources de contraintes, nous montrons que le tissu se comporte de manière effective comme un fluide viscoélastique avec un temps de relaxation fixé par les taux de division et d\'apoptose. Si le tissu est confiné dans un volume donné, il atteint un état homéostatique dans lequel division et apoptose s\'équilibrent. Dans cet état, les cellules subissent un mouvement diffusif aléatoire dû à la stochasticité de la division et de l\'apoptose. Nous calculons le coefficient de diffusion effectif en fonction des paramètres du tissu et comparons nos résultats concernant à la fois la diffusion et la viscosité à des simulations numériques de tels systèmes multicellulaires. En introduisant un deuxième composant qui représente le liquide extracellulaire, nous montrons qu\'une perméabilité finie du tissu donne lieu à des effets mécaniques supplémentaires. Dans la limite des temps longs, la réponse mécanique du tissu à des perturbations extérieures est confinée à une région dont la taille dépend du rapport entre la viscosité tissulaire et le coefficient de frottement entre les cellules et le liquide extracellulaire. La description à deux composants permet en outre de distinguer clairement les différentes contributions à la partie isotrope de la contrainte mécanique, c\'est-à-dire la pression du fluide et la contrainte exercée par les cellules. Finalement, nous étudions la propagation d\'une interface entre deux populations de cellules différentes, due à des différences dans le contrôle mécanique des taux de division et de mort cellulaire. En combinant de simples limites analytiques et des simulations numériques, nous distinguons deux modes de propagation différents de la population cellulaire la plus proliférante : un régime diffusif dans lequel les flux relatifs dominent l\'expansion, et un régime de propulsion dans lequel la prolifération domine et entraine des flux convectifs
Ben, Hamida Malek. "Analyse et validation du comportement directionnel des outils de forage couplés aux systèmes de forage dirigé". Thesis, Paris, ENMP, 2013. http://www.theses.fr/2013ENMP0054/document.
Texto completoThis work deals with the formulation of global relationships between kinematic variables describing the penetration of a PDC bit into the rock and drilling forces acting on it. This allows us determine the bit directional properties in terms of steerability, which corresponds to the bit lateral aggressiveness, and walk, which describes the bit azimuth displacement with respect to the side force. The bit kinematic quantities are divided into a three-axis penetration vector and a two-axis angular penetration vector. The bit tilt, which describes the angle between the bit revolution axis and the borehole tangent, is used to compute the effective interaction surface between the bit's different components (cutting structure, active gauge and passive gauge) and the rock. A new cutter-rock interface law is set up and experimentally validated in order to compute elementary forces acting on all parts of a drill bit. Bit directional properties are computed after the integration of these elementary forces. The bit-rock interaction model is experimentally validated with directional drilling tests held on a full-scale drilling bench developed to reproduce Rotary Steerable Systems (RSS) directional behavior. Tests and theoretical results enabled us to fully understand the roles of tilt angle, bit design, operating parameters and rock properties in the deviation process of a PDC bit. The bit-rock interaction model is a decision support tool for optimal drill bit selection according to the RSS being used. It could also be embedded in a real-time Closed-Loop Guided Directional Drilling controller in order to correct the drilling direction or follow a planned borehole trajectory
Lombardi, Giulia. "Unified nonlinear electrical interfaces for hybrid piezoelectric-electromagnetic small-scale harvesting systems". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI101.
Texto completoIn this research work, electronic nonlinear interfaces for hybrid energy harvesting systems combining piezoelectric and electromagnetic transducers are presented. Such systems have received great attention due to their ability to detect mechanical vibrations and convert them into electrical energy sufficient to power low-power sensors. In order to supply these microelectronic devices the generated sinusoidal signal needs to be rectified into a constant DC voltage. In other words, once the energy is converted, a proper and smart extraction of such energy needs to be implemented with a dedicated unit. The proposed nonlinear hybrid interfaces developed in this work, aimed at incorporating as much as electroactive parts as possible in the circuit, not only increase the final output power of the involved transducers but also provide a solution for obtaining a common optimal load value, despite dealing with elements singularly presenting different working principles and values of optimal load, without the use of additional load adaptation stages. A first solution is derived from the previously developed SSHI (Synchronized Switch Harvesting on Inductor) and based on the Synchronized Switching technique. This method aims at replacing the passive inductor in the SSHI interface with an active electromagnetic system, leading to an all-active microgenerators interface and increasing the final output power. A second solution is derived from a combination of the SECE (Synchronous Electric Charge Extraction) and SMFE (Synchronous Magnetic Flux Extraction) techniques. Its main principle consists of transferring the energy from the piezoelectric to the electromagnetic transducer and then extracting the boosted energy from the electromagnetic system. The strategy of including as much as electroactive parts within the same electrical interface open many different possibilities of interfacing more than one electroactive system, constituting hybrid energy harvesters, without including extra circuit stages, thus maintaining a relative simplicity without high power losses
Shahid, Zafar. "Protection des Vidéos Hiérarchiques par Cryptage et Tatouage". Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2010. http://tel.archives-ouvertes.fr/tel-00558849.
Texto completoMorin, Juliette. "Coordination des moyens de réglage de la tension à l'interface réseau de distribution et de transport; et évolution du réglage temps réel de la tension dans les réseaux de distribution". Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0020/document.
Texto completoVoltage and reactive power control are of paramount importance to ensure safe and reliable operation of the power system. Distribution grids are undergoing major changes, namely the insertion of distributed generation and the replacement of overhead lines. Along with these physical evolutions, new distribution networks should comply with the requirements of the European Grid Codes on the reactive power exchange at the HV/MV interface. To handle these new operational concerns, alternative solutions to the traditional voltage and reactive power control can be found. In our work, a scheme based on the evolution of the real-time Volt Var Control (VVC) of distribution networks and a joint coordination for the reactive power management of a HV system has been proposed. The real-time VVC of MV grids is based on a predictive control method. This control uses in a coordinated manner the on load tap changer, the distributed generation and the capacitor banks to enforce a suitable MV voltage profile and an appropriate HV/MV reactive power exchange. The reactive power targets at the HV/MV interface are determined by the Transmission System Operator for its own requirements but considering the true MV reactive power reserve. Compared to the literature, the novelty of our approach consists in considering the concerns at the HV/MV system interface. Next our works have shown the relevance of performing joint transmission and distribution system operators analysis
Purcell, Isabella Pauline. "Specular reflection from interfaces". Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386624.
Texto completoGuillamat, Bassedas Pau. "Control of active flows through soft interfaces". Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/404355.
Texto completoSistemes compostos per grups d’animals, colònies de bacteris, teixits de cèl·lules o assemblatges d’extractes cel·lulars, mostren comportaments dinàmics complexos significativament similars tot i que, evidentment, es desenvolupen a escales espai-temps molt diverses. Aquests sistemes, anomenats sistemes actius, estan generalment formats per unitats individuals auto-propulsades que consumeixen energia de l’ambient, a partir de la qual generen forces i treball mecànic. La interacció entre els constituents d’aquests sistemes propicia moviments col·lectius i cooperatius, així com patrons de flux que no s’observen en sistemes similars en equilibri termodinàmic. Tot i que les característiques morfològiques i dinàmiques d’aquests sistemes s’estan estudiant amb detall, manquen encara estratègies per controlar els fluxos actius que se’n deriven. L’habilitat de controlar sistemes actius, no només en facilita la seva caracterització sinó que possibilita l’aplicació dels fluxos que se’n deriven, per exemple, en dispositius. Amb aquest objectiu, aquesta tesi se centra en el desenvolupament d’estratègies per al condicionament i control de fluxos actius mitjançant constriccions que procuren ser no invasives per als materials implicats. El material estudiat consisteix en un gel actiu aquós format per agregats de microtúbuls, reticulats per complexos de motors moleculars. En presència d’Adenosina trifosfat (ATP), els complexos motors exerceixen forces de cisalla locals entre els microtúbuls que, globalment, provoquen contínuament l’extensió, flexió i trencament dels agregats filamentosos. La interacció entre els constituents actius genera fluxos turbulents a escales molt més grans que les pròpies de les unitats constitutives del material. D’altra banda, en presència d’una interfície aigua/oli correctament funcionalitzada, el gel es pot densificar, desenvolupant els seus fluxos en contacte amb la fase oliosa. D’aquesta manera, s’obté un material actiu quasi-bidimensional molt dens, en el qual els filaments interaccionen entre si i s’organitzen en el pla donant lloc a un gel actiu amb ordre orientational. En particular, en aquesta tesi, s’estudiarà l’efecte de l’acoblament hidrodinàmic d’aquest material amb fluids viscosos isotròpics, amb patrons reològics imposats per cristalls líquids i en confinament, com a eines per al control dels fluxos, fins ara, aparentment caòtics i impredictibles d’aquests sistemes actius.
NGUYEN, Ngoc Trung. "Study and development of innovative measurement methods and systems for anti-islanding protection in smart grids". Doctoral thesis, Università degli Studi di Palermo, 2014. http://hdl.handle.net/10447/90786.
Texto completoSu, Tsueu-Ju. "Neutron and X-ray scattering from interfaces". Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319060.
Texto completoMocellin, Françoise. "Gestion de données et de présentations multimédias par un SGBD à objets". Phd thesis, Université Joseph Fourier (Grenoble), 1997. http://tel.archives-ouvertes.fr/tel-00004956.
Texto completoMadhusudan, Seegapalya. "A Literature study on Factors that enables Communication between R&D and Manufacturing". Thesis, Linköping University, Linköping University, Department of Management and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19260.
Texto completoCommunication, coordination and cooperation are critical for a successful organization. This master's thesis work presents a literature study of the factors that influence the interface between Research & development and manufacturing functions. Research & development and manufacturing functions rarely share information among each other and rarely combine their skills and knowledge to produce effective and efficient work within organization. This is due to lack of mutual understanding improper communication and coordination among members in the teams. In the late 1990's, competition, Information Technology proliferation, increasing customer demands for better products at shorter lead times emphasized increased need for effective product development. Each function has its specialization and is effective in their domain. Each department has roles and responsibilities to complete given tasks. But they neglect the organizational and management issues and lack the focus where they are a part of a bigger process (i.e. delivering value to customer and making the company successful at the end of the day). The main focus of the thesis is to give deeper knowledge on communication and coordination between Research and Development and manufacturing. This is achieved by review of the articles, analysis and finally synthesis of literature to develop constructs and analysis models. This will help to understand the factors and its interaction. The factors identified are individual responsibilities, artefacts and system or domain understanding, communication idea, control and role distribution, teams, accessibility and arena for personal meetings and finally overall leadership.
Each factor has its own and unique contribution to success with in the organization. These factors are interrelated and dependent on one another. Artefacts understanding deals with some actions and steps has to be taken in order to executive the give tasks, individual role plays an important role in what sense he\she will contribute to the team as well as to the organization. Even active responsibilities must understand the system or domain and quickly adjust to the environment and get practice on it. Teams are essential tool in any organization, working together creates creative problem solving, improves effective of communication, improves development skills and ability of an individual, mutual understanding and cooperation among group members all will constitute to the teams. Finally teams are the critical building blocks of an organization. The model developed needs further testing through empirical evidence to increase its validity.
Madhusudan, Seegapalya Chikkagangaiah. "A Literature study on Factors that enables Communication between R&D and Manufacturing". Thesis, Linköpings universitet, Kvalitetsteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19260.
Texto completoTournebize, Aurélien. "Structure électronique et stabilité de matériaux pour le photovoltaïque organique". Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22654/document.
Texto completoThis word was devoted to the stability in various conditions of materials used in the active layer of organic solar cells. The main goals of this work were first to provide deeper understanding about complex mechanisms occurring in the active layer and second to investigate interfacial degradation pathways involving the active layer. A first part was dedicated to the photo and thermal stability of the polymer blend materials which constitute the active layer of the solar cells. A second section focused on the role of the third component of the active layer which can be undesired residual additives coming from the processing or the desired insertion of a stabilizer additive. A third part concerned the delamination issue which takes place at the active layer / hole transporting layer interface. Finally, a last section was devoted to the energy level alignment between the C60 molecules and various electron transporting substrates. The photo and thermal stability of the active layer / electron transporting layer interface was also studied in this section
Teixeira, Francisco José. "Polymer-modified oligonucleotide sequences : towards biologically active self-assembled interfaces /". Basel : [s.n.], 2009. http://edoc.unibas.ch/diss/DissB_8936.
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