Tesis sobre el tema "Interface Force"
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Borg, Malin, Elias Ghattas y Ardian Syla. "Graphical User Interface for Intermodulation Atomic Force Microscopyok". Thesis, KTH, Tillämpad fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105518.
Texto completoVid atomic force microscopy (AFM) fors en skarp spets, placerad pa den fria anden av en kantilever, over en yta. Krafterna fran ytan pa spetsen orsakar avvikelser i kantileverns beteende, vilket registreras av en detektor. Denna information utnyttjas sedan for att skapa en topogrask bild av ytan i nanoskala. Vi var involverarde i ett projekt dar det utvecklas en ny typ av AFM, intermodulation atomic force microscopy (IMAFM). Denna grundar sig pa dynamisk AFM, men istallet for en drivfrekvens utnyttjas tva eller era. Vilket i sin tur genererar mer information fran samma matning. Var uppgift i projektet var att utveckla mjukvaran som anvands vid experimenten. Detta for att underlatta framtida experiment samt utnyttja den tillgangliga informationen pa ett nytt satt.
Okunribido, Olanrewaju Olusegun. "Effect of handle configuration in force exertion". Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367802.
Texto completoHafizović, Sadik. "Neural interface and atomic-force microscope in CMOS technology /". Zürich : Physical Electronics Laboratory, ETH Zürich, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16806.
Texto completoMcGee, Marilyn Rose. "Investigating a multimodal solution for improving force feedback generated textures". Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274183.
Texto completoIarikov, Dmitri. "Molecular thin films and their role in controlling interface properties". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51675.
Texto completoPh. D.
Massie, Thomas Harold. "Design of a three degree of freedom force-reflecting haptic interface". Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/11281.
Texto completoLee, Jung-Hyun. "Interface engineering in zeolite-polymer and metal-polymer hybrid materials". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37120.
Texto completoStaheli, Kimberlie. "Jacking Force Prediction: An Interface Friction Approach based on Pipe Surface Roughness". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-07052006-203035/.
Texto completoDr. J. David Frost, Committee Chair ; Dr. G. Wayne Clough, Committee Co-Chair ; Dr. William F. Marcuson III, Committee Member ; Dr. Paul W. Mayne, Committee Member ; Dr. Susan Burns, Committee Member.
Haschke, Heiko. "Force spectroscopy and microscopy of single molecules at the solid-liquid interface". Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288334.
Texto completoLabuda, Aleksander. "Adventures in atomic force microscopy towards the study of the solid-liquid interface". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110355.
Texto completoCette thèse présente la conception et le développement d'un microscope électrochimique à force atomique (AFM) équipé d'excitation photothermique pour l'actionnement du levier pour l'étude de l'interface solide-liquide. Une analyse rigoureuse de bruit dans la méthode de déviation du faisceau optique est présentée et conduit à des nouvelles techniques pour la réduction du bruit de détection à des niveaux en dessous du bruit thermique du levier. Une simulation stochastique d'AFM démontre que le bruit thermique limite fondamentalement la mesure des structures d'hydratation à l'interface mica/eau, tandis que les vibrations méchaniques peuvent dominer la mesure des deux dernières couches d'hydratation au dessus de la surface. Des problèmes couramment négligés associés à l'excitation piezoacoustique traditionnellement utilisée sont décrits et quantifiés par rapport à la modulation de fréquence (FM) et à la modulation d'amplitude (AM) des méthodes de l'AFM en mode dynamique. Après une description de la mécanique statistique de la double couche électrique (EDL) de solutions aqueuses, des measures de spectroscopie de force de l'interface mica-eau acquises en mode FM-AFM en trois dimensions sont présentées à côté d'une analyse détaillée des profils d'amortissement et de la force utilisée pour la détermination d'une distance absolue entre la pointe et l'échantillon par comparaison à des simulations. Enfin, la mécanique statistique de l'électrochimie ionique moderne est vulgarisée, suivie d'une enquête approfondie de la voltampérométrie cyclique du 1-butyl-3-méthylimidazolium hexafluorophosphate près de l'interface du Au(111) avec comparaison avec les résultats publiés de spectroscopie d'impédance électrochimique. Les observations électrochimiques sont complétées par des mesures de spectroscopie de force réalisée à l'aide d'AM-AFM à différents potentiels électrochimiques d'électrodes à travers une fenêtre de 2 V - aucune relation entre la structure et le potentiel EDL n'a été observée.
Jurečka, Jaroslav. "Konstrukce hmatového rozhraní pro výstupní zařízení virtuální reality". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227887.
Texto completoZane, Lisa. "Force measures at the hand-stick interface during ice hockey slap and wrist shots". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110526.
Texto completoLe but de cette étude était d'examiner les forces de contact entre les mains et le baton de hockey pendant l'exécution de lancers frappés et de tirs du poignet. Quatre cohortes (homme/femme x haut / bas calibre; HC, LC) de joueurs de hockey sur glace ont été testés en utilisant trois bâtons de rigidités différentes (77, 87, 102). Quarante et un sujets (21 hommes, 20 femmes) ont effectué sept lancers frappés et sept tirs du poignet avec chacun des trois types de bâton. La force de pression a été enregistrée à 1000 Hz en utilisant 32 capteurs piézorésistifs aux interfaces entre la main et le bâton. Les résultats ont démontré la faisabilité de la mesure directe des forces à l'interface main-bâton lors de l'exécution de tirs au hockey sur glace. Les forces de pointe atteintes au cours de lancers frappés et de tirs du poignet différaient en fonction du calibre et du sexe, les hommes présentant des forces supérieures comparativement aux femmes. De plus, les joueurs de HC ont démontré des forces supérieures par rapport aux joueurs LC. Par contre, le type de bâton ne représentait pas un facteurs significatif pour la production de force qui plus est, chaque joueur a affiché une 'signature' de force reproductible et constante. En général, les modèles de forces pour les lancers frappés et les tirs des poignets ont démontré des pattrons de coordination bimanuelle à la compréhension du contrôle mécanique dynamique du bâton et possiblement a l'évaluation de la performance.
Hjalmarsson, Nicklas. "Ionic liquids : The solid-liquid interface and surface forces". Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186267.
Texto completoJonvätskor möjliggör nya tillvägagångssätt för att kontrollera interaktioner vid gränsskiktet mellan fasta ytor och vätskor. Jonvätskor definieras som vätskor som består av stora och asymmetriska joner med en smältpunkt under 373 K. På grund av sin amfifila karaktär är de starka lösningsmedel men har också andra intressanta egenskaper. Jonvätskor kan till exempel självorganisera sig och attraheras till ytor på grund av sin laddning. En följd av detta är att de bildar nanostrukturer både i bulk och på ytor. Denna avhandling beskriver hur gränsskiktet mellan fasta ytor och jonvätskor svarar på yttre påverkan såsom en ökning i temperatur, tillsättning av ett salt samt polarisering. En ökad förståelse för hur dessa faktorer styr ytkompositionen av jonvätskor kan bidra med verktyg för att kontrollera system till specifika applikationer såsom friktion. Normala- och friktionskrafter mäts för etylammonium nitrat (EAN) mellan en glimmeryta och en kolloidprob vid olika temperaturer eller saltkoncentrationer. Resultaten visar att en ökning av temperatur eller låga koncentrationer av tillsatt salt bara marginellt framkallar ändringar i strukturen på gränsytan och att det adsorberade lagret förblir intakt. När saltkoncentrationen emellertid var tillräckligt hög får den mindre litiumjonen överhanden och ytsammansättningen ändras. Ytlagret av en liknande jonvätska undersöks också vid tillsättning av salt och resultaten avslöjar att litiumjoner påverkar ytsammansättningen annorlunda beroende på jonstrukturen av jonvätskan. Detta visar att ytselektiviteten starkt beror på jonkemin. En repulsiv dubbellagerkraft yttrar sig anmärkningsvärt för EAN vid 393 K vilket inte observeras vid lägre temperaturer. Detta indikerar en ändring i EANs mikroskopiska sammansättningsbeteende och har generella återverkningar för hur jonvätskor uppfattas. En ny metod har utvecklats baserad på en kvartskristall mikrovåg för att undersöka hur ytsammansättningen av jonvätskor reagerar på polarisering. Denna metod visar att det adsorberade lagret av både en ren jonvätska och en jonvätska löst i olja kan kontrolleras genom att applicera spänningar med olika tecken och storlekar. Dessutom möjliggör metoden två oberoende tillvägagångssätt för att övervaka laddningarna under polarisering vilket kan användas för att kvantifiera ytsammansättningen. Tekniken ger också information om jonkinetik och ytselektivitet. Detta arbete bidrar till den grundläggande förståelsen av gränsskiktet mellan fasta ytor och jonvätskor och visar att ytsammansättningen av jonvätskor kan kontrolleras och övervakas med olika tillvägagångssätt.
QC 20160518
CHANDER, DIVYAKSH SUBHASH. "Modelling the Physical Human-Exoskeleton Interface". Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2928614.
Texto completoPetit, Julien. "Déformations et instabilités d’interfaces liquides pilotées par la diffusion d’une onde laser en milieux turbides". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14454/document.
Texto completoThis thesis work is dedicated to liquid interface deformations from a continuous laser wave. We demonstrate that elastic scattering of the incident wave in turbid medium induces a scattering force density giving birth to permanent bulk flows in the fluid. Near a soft interface, viscous stresses associated to these flows can deform the interface up to instability and produce a liquid jet. In this manuscript, we report an experimental study dedicated to this new light-fluid coupling in combination with numerical simulations. We also study interface deformations and instability induced by radiation pressure, due to refractive index contrast between the two liquid phases in coexistence, in transparent fluids. We finally analyzed the combination of both couplings in turbid media, scattering force and radiation pressure which differently operate for the interface deformation. To do this, we used different turbid and transparent fluids systems, which have the main particularity to present very low interfacial tension
Thoreson, Erik J. "Apparatus to deliver light to the tip-sample interface of an atomic force microscope (AFM)". Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-1003102-092130.
Texto completoKeywords: purple membrane; photomechanics; photoinduced conformation change; photocycle; photoactive; photoinduced; bimetallic bending; bacteriorhodopsin; atomic force microscope; tip-sample interface; molecular conformation; PLDS; photoreactive; AFM. Includes bibliographical references (p. E-1-E-4).
Rigsby, Benjamin. "Force Compensation and Recreation Accuracy in Humans". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6938.
Texto completoTsagarakis, N. G. "Integrated haptic interface : tactile and force feedback for improved realism in VR and telepresence applications". Thesis, University of Salford, 2000. http://usir.salford.ac.uk/26946/.
Texto completoLevesque, Laurent De B. "Experimental Evaluation and Characterization of a Mobility Assist Device Physical Interface". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37365.
Texto completoLundqvist, Rasmus y Tobias Söreling. "New Interface for Rapid Feedback Control on ABB-Robots". Thesis, Linköping University, Department of Mechanical Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2762.
Texto completoAutomation in manufacturing has come far by using industrial robots. However, industrial robots require tremendous efforts in static calibration due to their lack of senses. Force and vision are the most useful sensing capabilities for a robot system operating in an unknown or uncalibrated environment [4]and by integrating sensors in real-time with industrial robot controllers, dynamic processes need far less calibration which leads to reduced lead time. By using robot systems which are more dynamic and can perform complex tasks with simple instructions, the production efficiency will rise and hence also the profit for companies using them.
Although much research has been presented within the research community, current industrial robot systems have very limited support for external sensor feedback, and the state-of-the-art robots today have generally no feedback loop that can handle external force- or position controlled feedback. Where it exists, feedback at the rate of 10 Hz is considered to berare and is far from real-time control.
A new system where the feedback control can be possible within a real-time behavior, developed at Lund Institute of Technology, has been implemented and deployed at Linköping Institute of Technology.
The new system for rapid feedback control is a highly complex system, possible to install in existing robot cells, and enables real-time (250 Hz) sensor feedback to the robot controller. However, the system is not yet fully developed, and a lot of issues need to be considered before it can reach the market in other than specific applications.
The implementation and deployment of the new interface at LiTH shows that the potential for this system is large, since it makes production with robots exceedingly flexible and dynamic, and the fact that the system works with real- time feedback makes industrial robots more useful in tasks for manufacturing.
Weill-Duflos, Antoine. "Interfaces et capteurs pour une chaine de micro-téléopération". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066147/document.
Texto completoTeleoperation opens up new possibilities for interaction with the micro-world. Adequate systems make it possible for human to manipulate elements on microscopic scales. An added haptic feedback provides information crucial for a natural interaction. A bilateral coupling between the subsystems offers the best haptic transparency. This thesis addresses the design of a complete haptic teleoperation chain by focusing on its key elements. Three parts are detailed: The first part describes improvements of the high fidelity one degree of freedom haptic interface designed previously. First, the precision of the forces produced is improved. This improvement is related to the measurement of the motor velocity at high sampling frequencies. Then, the device is precisely caracterized. The second part describes the design of two new force sensors designed specifically for interactions with the micro-world. The forces are measured by compensation. Two approach are observed to expand the frequencies of forces measurable by the sensors. First approach try to reduce the mass, a new sensor on a micrometric scale is built with MEMS technologies. The second approach offer a new design of the sensor. In particular, the stiffness in the guidance is removed. The third part describes the design of a new haptic interface with multiple degrees of freedom. This interface combines the performances of the one degree of freedom interface with a 2D configuration. The key elements of its design are the an air bearing for frictionless guidance and linear induction motors for reduced inertia
Blom, 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 completoHashimoto, Kota. "Inverse analysis of the structures of the liquid molecules and colloidal particles near the solid-liquid interfaces: the relation between the number density distribution and the experimental force curve". Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263678.
Texto completoPouvreau, Maxime. "Amélioration d'un champ de force pour la description des bordures de particules argileuses". Thesis, Nantes, Ecole des Mines, 2016. http://www.theses.fr/2016EMNA0291/document.
Texto completoThe CLAYFF force field is widely used to model the interfaces of clay minerals – and related layered materials – with an aqueous phase. In the simulations, clay particles are typically represented by semi-infinite layers, i.e. only surfaces parallel to the layer plane (basal surfaces) are considered. This simplification is acceptable to a certain extent, but clay layers are really nanosized and terminated by lateral surfaces or edges. These surfaces can not only adsorb solvated species but are also subject to proton transfers, and all physico-chemical processes related to the aqueous phase acidity predominantly occur at the edges. By adding to the CLAYFF force field a Metal-O‑H angle bending term whose parameters are correctly adjusted, the simulations of edge interfaces become possible.The parameters of Al-O‑H and Mg-O‑H terms were obtained from DFT calculations on bulk, basal surface and edge structural models of gibbsite Al(OH)3 and brucite Mg(OH)2, whose layers can be considered as the backbones of clay minerals and related materials. In addition, the Si-O‑H term was parametrized from an edge model of kaolinite Al2Si2O5(OH)4 . Molecular dynamics simulations based on DFT and on CLAYFF with and without Metal-O‑H term were performed. The modified force field clearly improves the description of hydroxylated surfaces : the orientation and the librational dynamics of the hydroxyl groups, the hydrogen bonding, and the coordination of metal atoms belonging to the edge are all closer to reality
Rastogi, Anisha. "NEURAL REPRESENTATION OF FORCE, GRASP, AND VOLITIONAL STATE IN INTRACORTICAL BRAIN-COMPUTER INTERFACE UERS WITH TETRAPLEGIA". Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1599484170191229.
Texto completoEster, Guy R. "An atomic force microscopy study of the crystal growth interface of solution grown potassium hydrogen phthalate". Thesis, University of Bath, 1999. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299809.
Texto completoRaymand, David. "Surface and Interface Studies of ZnO using Reactive Dynamics Simulation". Doctoral thesis, Uppsala universitet, Strukturkemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-129304.
Texto completoChia, Chung Lim. "Classical and ReaxFF molecular dynamics simulations of fuel additives at the solid-fluid interface". Thesis, University of Manchester, 2019. https://www.research.manchester.ac.uk/portal/en/theses/classical-and-reaxff-molecular-dynamics-simulations-of-fuel-additives-at-the-solidfluid-interface(a1a5cb5d-3283-4ebc-9ef1-b44aac16821b).html.
Texto completoMarutschke, Christoph Peter [Verfasser]. "Three-dimensional imaging of the solid-liquid interface with high-resolution atomic force microscopy / Christoph Peter Marutschke". Mainz : Universitätsbibliothek Mainz, 2016. http://d-nb.info/1121241832/34.
Texto completoJoshi, Swapneel. "A study of pressure and shear force at the foot/shoe interface- a review of the literature". Thesis, University of Strathclyde, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502333.
Texto completoMahmoud, Ahmad. "Implant-Abutment Interface: A Comparison of the Ultimate Force to Cause Failure between Small Diameter Implant Systems". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354197449.
Texto completoKao-Walter, Sharon. "On the Fracture of Thin Laminates". Doctoral thesis, Karlskrona : Blekinge Institute of Technology, 2004. http://www.bth.se/fou/forskinfo.nsf/01f1d3898cbbd490c12568160037fb62/8234b0fbc62f096ac1256f9500478384!OpenDocument.
Texto completoGonzález, García Cristina. "BIOLOGICAL ACTIVITY OF FIBRONECTIN AT THE CELL-MATERIAL INTERFACE". Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/17701.
Texto completoGonzález García, C. (2012). BIOLOGICAL ACTIVITY OF FIBRONECTIN AT THE CELL-MATERIAL INTERFACE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17701
Palancia
Bhoot, Satbinder Singh. "A problem at the manufacturing marketing interface : customer scheduling for a sales force in the industrial market sector". Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247060.
Texto completoWang, Junfang. "Efficient Positioning Technique for Multi-Interface Multi-Rate Wireless Mesh Networks". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1289937715.
Texto completoTreps, Laureline. "Définition à l'échelle atomique de la surface externe de la zéolithe ZSM-5 et de son interface avec le liant". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN040.
Texto completoZeolites are nanoporous aluminosilicates crystals of prominent fundamental and industrial importance. Among these, ZSM-5 is one of the most investigated solid, with paramount industrial use, that can be obtained in various forms. Some of these (hierarchical forms, nanoslabs, nanosheets and nanocrystals) exhibit a very high surface over volume ratio which make them useful for multiple industrial processes. The shaping is used to adapt ZSM-5 (and zeolites in general) to the needs of the industrial reactors. Empirically, preparing a technical zeolite is a strong industrial know-how, but with limited physic-chemical understanding of the zeolite-binder interface. Periodic Density Functional Theory (DFT, VASP, PAW, PBE dDsC) calculations of the relative stability of relevant surface orientations for silicalite and ZSM-5 crystals ((100), (010) and (101)) were performed at different hydration levels thanks to ab initio thermodynamics. Their relative acidities (pyridine and di-tertbutylpyridine adsorption) and spectral features (vibration modes, NMR chemical shifts) are determined. The interaction of the most relevant ones with binders (alumina, silica) is simulated ab initio, and an empirical reactive force field (ReaxFF) is built on purpose to model larger scales. Several kinds of surface sites have been identified. Bridging Al-OH-Si are present at the pore mouth, of similar or higher stability with respect to bulk sites. These are not stable at the outermost surface, where the following groups prevail: Si-OH, Al-OH and most importantly water adsorbed on aluminum Al-(H2O)(OH)n. Models of pyridine and 2,6-ditertbutylpyridine adsorption show that the acidity of the bridging groups is stronger than the other, and more particularly with a strong confinement. Al-(H2O)(OH)n surface site are shown to be the most stable at the external surface of ZSM-5 and are studied upon the hydration and dehydration of the ZSM-5 external surfaces. The results issue from these DFT simulations are compared to FT-IR, 1H NMR, and pyridine/2,6-ditertbutylpyridine adsorption experiments conducted at IFPEN. The interaction between zeolite and binders (silica, alumina) is first modeled by the interaction of the zeolite with small components like Si(OH)4, Na+ - present in some silica sources - and Al(OH)3(H2O). The results show that alumina components are more strongly attracted by the aluminum of the zeolitic network than silicic species. Na+ binds more strongly with the zeolite rather than silica and these results are once more compared to experimental data. The reactive force field parameters optimization is allowing to model larger external zeolite surfaces that are in contact with more realistic binder surfaces. All these results provide a rational understanding of a large set of experimental observations from the literature, that remained so far poorly understood. These findings are likely not limited to the case of the MFI framework (some of them already appeared to be valid for zeolite Beta), as our conclusions are mainly dictated by local topology aspects. The zeolite we investigate and the reactive sites we reveal are of both fundamental and industrial importance
Paluszek, Matthew Alan. "Methods and Applications of Controlling Biomimetic Robotic Hands". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/25335.
Texto completoMaster of Science
Okubo, Hitoshi, Masafumi Takei, Yoshikazu Hoshina, Masahiro Hanai, Katsumi Kato y Muneaki Kurimoto. "Application of Functionally Graded Material for Reducing Electric Field on Electrode and Spacer Interface". IEEE, 2010. http://hdl.handle.net/2237/14528.
Texto completoCisotto, Giulia. "Movement-Related Desynchronization in EEG-based Brain-Computer Interface applications for stroke motor rehabilitation". Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423860.
Texto completoL'identificazione e la quantificazione in tempo reale dei correlati cerebrali del movimento e' uno degli aspetti piu' critici nell'ambito delle cosiddette Brain-Computer Interface (BCI), ovvero quelle applicazioni in cui un individuo, dopo uno specifico percorso di apprendimento, impara a controllare un computer (o un altro dispositivo) tramite la modulazione volontaria della sua attivita' cerebrale, con lo scopo finale di trarre vantaggio dall'utilizzo dell'apparecchiatura cosi' controllata. La BCI e' solo uno delle molteplici tecniche di riabilitazione motoria oggigiorno disponibili. Indipendentemente dalla specifica tecnica scelta, il metodo riabilitativo mira a recuperare le funzionalita' del cosiddetto sistema sensorimotorio, quel complesso di aree corticali e strutture sotto-corticali che permette ad un individuo di ricevere impulsi somatosensoriali dal mondo esterno, di elaborare la risposta motoria piu' opportuna e realizzarla grazie agli attuatori finali del movimento rappresentati dai muscoli. Per perseguire questo obbiettivo, la maggior parte delle tecniche riabilitative, ivi compresa la BCI, pongono grande attenzione alla promozione e sfruttamento di quei processi spontanei che il cervello costantemente impiega per svolgere le sue attivita', adattarsi a nuove condizioni ambientali e anche cercare di recuperare le abilita' perse a seguito di un evento dannoso quale un ictus. Questi fenomeni vengono generalmente riassunti nel termine neuroplasticita' e sono stati paradossalmente sfruttati per anni nella pratica clinica, ma solo recentemente sono diventati materia di rigorosi e approfonditi studi scientici portati avanti da neuroscienziati provenienti da ogni tipo di formazione (neurologi, neurofisiologi, biologi, ingegneri, neuropsicologi, ...). Nel particolare contesto della riabilitazione motoria che ambisce essenzialmente a promuovere fenomeni di (ri-)apprendimento motorio da parte del paziente colpito da ictus, la letteratura ha fermamente indicato il condizionamento operante come la strategia piu' efficace per favorire i processi di plasticita' corticale e, di conseguenza, il recupero, seppur parziale, della motricita'. Il condizionamento operante si applica tramite la ripetitiva associazione di un comportamento corretto (scorretto) effettuato dal soggetto e uno stimolo gratificante (penalizzante) dato contestualmente o in un tempo appena successivo all'esecuzione del comportamento. Sfruttando il fondamentale meccanismo di apprendimento del cervello per prove ed errori, esso impara a utilizzare il comportamento corretto per svolgere il compito richiesto. Tale comportamento corretto e', in questo caso, lo sfruttamento di risorse ridondanti prima dell'ictus ma ancora sane dopo l'evento per controllare le funzioni motorie rimaste indebolite o completamente perse a seguito del danno cerebrale. Data la fondamentale importanza della contingenza tra l'attivita' cerebrale del paziente coinvolto nell'esperimento e lo stimolo di feedback, un robusto algoritmo di elaborazione del segnale cerebrale si rende fortemente necessario. In questo lavoro di tesi e' stata analizzata una particolare applicazione BCI per la riabilitazione motoria di pazienti lievemente o moderatamente aetti da emiparesi dovuta a ictus e sono stati proposti degli algoritmi con la relativa soluzione software per la realizzazione ottimale della strategia di apprendimento operante durante il recupero di un movimento di raggiungimento. Il vincolo principale da considerare per ottenere questo tipo di risultato e' la possibilita' di identificare e quanticare il correlato neurofisiologico legato al movimento, la cosiddetta desincronizzazione movimento correlata, in tempo reale durante l'esecuzione del movimento da parte del soggetto. Nell'ottica del condizionamento operante, un dispositivo haptico inserito nel sistema funge da feedback positivo che aiuta il paziente a completare il movimento nel solo caso in cui venga riconosciuta la desincronizzazione. In caso contrario, il soggetto non riceve alcun feedback o il suo movimento viene reso piu' difficile. Dopo un primo capitolo introduttivo sul sistema sensorimotorio arricchito con alcune informazioni riguardanti la particolare patologia in questione, il secondo capitolo introduce gli elementi fondamentali della piattaforma sperimentale utilizzata, ovvero l'elettroencefalogramma (EEG) e la BCI nella sua accezione generale, accennando anche ai maggiori successi in questo ambito delle ICT applicate alla medicina riabilitativa. Nel capitolo 3 viene descritta la particolare piattaforma BCI basata su EEG menzionata sopra e nei capitoli 4 e 5 vengono presentate ampiamente le analisi, le procedure e i risultati sviluppati ed ottenuti in questi anni di studio. In particolare, nella prima parte del capitolo 4 viene illustrato l'algoritmo con cui e' possibile identificare e rimuovere in tempo reale un particolare evento di disturbo che puo' verificarsi durante la registrazione EEG, il cosiddetto artefatto electrode pop dovuto al temporaneo sollevamento di un elettrodo che causa abnormi valori negativi nelle tracce EEG. Una volta rimosso questo tipo di eventp, il segnale viene filtrato e nella seconda parte del capitolo 4 viene presentata un'esaustiva analisi dell'energia delle tracce EEG acquisite durante la registrazione dell'esperimento di cui sopra in soggetti sani di controllo e in alcuni pazienti reduci da ictus. Inoltre, viene suggerita una versione modificata del piu' noto metodo di quantificazione della desincronizzazione fornito da Pfurtscheller e colleghi a partire dagli anni '70 i cui risultati promettenti sono forniti e discussi nel capitolo finale della tesi. La tesi si conclude con una breve sezione dedicata alle prospettive future di applicazione della piattaforma con l'integrazione delle soluzioni software apportate da questa tesi e alle questioni ancora aperte da risolvere al fine di ottimizzare il sistema BCI in tutti i suoi aspetti in modo da realizzare nel modo piu efficace il condizionamento operante e promuovere quei processi spontanei che sottostanno al recupero funzionale della motricita'.
Schonjahn, Cornelia. "Surface treatment in a cathodic arc plasma : key step for interface engineering". Thesis, Sheffield Hallam University, 2001. http://shura.shu.ac.uk/20336/.
Texto completoNita, Sorin. "Insights into the solvation and selectivity of chiral stationary phases using molecular dynamics simulations and chemical force microscopy". Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1348.
Texto completoMarques, Daniel Filipe da Ponte. "Development of training tools for haptic teleoperation of a humanoid robot". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16450.
Texto completoIn robotics, the teleoperation of biped humanoids is one of the most exciting topics. It has the possibility to bypass complex dynamic models with learning demonstration algorithms using human interaction. For this procedure, the Humanoid Project at the University of Aveiro - PHUA, ingrained in the production of a 27 degree-of-freedom full body humanoid platform teleoperated by means of haptic devices. The current project also comprises a robot model that has be imported into the Virtual Robot Experimentation Platform: V-REP. The usage of the simulator allows multiple exercises with greater speed and shorted setup times, when compared to the teleoperation of the real robot, besides providing more safety for the platform and the operator during the tests. By using the simulator, the user can perform tests and make achievements towards the reproduction of human movement with the interaction of two haptic devices providing force feedback to the operator. The performed maneuvers have their kinematic and dynamic data stored for later application in learning by demonstration algorithms. However, the production of more complex and detailed movements requires large amounts of motor skill from the operator. Due to the continuous change of users in the PHUA, an adaptation period is required for the newly arrived operators to develop an a nity with the complex control system. This work is focused on developing methodologies to lower the required time for the training process. Thanks to the versatility of customization provided by V-REP, it was possible to implement interfaces which utilized visual and haptic guidance to enhance the learning capabilities of the operator. A dedicate workstation, new formulations and support tools that control the simulation were developed in order to create a more intuitive control over the humanoid platform. Operators were instructed to reproduce complex 3D movements under several training conditions (with visual and haptic feedback, only haptic feedback, only visual feedback, with guidance tools and without guidance). Performance was measured in terms of speed, drift from intended trajectory, response to the drift and amplitude of the movement. Findings of this study indicate that, with the newly implemented mechanisms, operators are able to gain control over the humanoid platform within a relatively short period of training. Operators subjected to the guidance programs present an even shorter period of training needed, exhibiting high performance in the overall system. These facts support the role of haptic guidance in acquiring kinesthetic memory in high DOFs systems.
Em robótica, a teleoperação de robôs bípede humanóides é um dos tópicos mais emocionante. Tem a possibilidade de contornar modelos dinâmicos rígidos, com algoritmos de aprendizagem por demonstração utilizando interação humana. Para este procedimento, o Projeto Humanóide da Universidade de Aveiro - PHUA, empanha-se na produção de uma plataforma humanóide de corpo inteiro teleoperado com dispositivos hapticos. O estado presente do projeto apresenta um robô humanóide com 27 graus de liberdade. O projeto actual apresenta um modelo do robô importado para a Virtual Robot Exper- imentation Platform: V-REP. O uso do simulador permite vários exercícios com maior velocidade e tempos de preparação curtos, quando comparado com a teleoperação do robô real, além de proporcionar mais segurança para a plataforma e do operador durante os ensaios. Ao utilizar o simulador, o utilizador pode realizar testes à reprodução de movimento humano com a interacção de dois dispositivos de meios hápticos que fornecem força de retorno para o operador. As manobras realizadas têm os seus dados cinemáticos e dinâmicos armazenados para posterior aplicação na aprendizagem por algoritmos de demonstração. No entanto, a produção de movimentos mais complexos e detalhados requer grandes quantidades de habilidade motora do operador. Devido à mudança contínua de usuários no PHUA, um período de adaptação é necessário para os operadores recém-chegados a desenvolver uma a nidade com o complexo sistema de controlo. Este trabalho é focado no desenvolvimento de metodologias para diminuir o tempo necessário para o processo de formação dos utilizadores. Graças à versatilidade de personalização fornecidos pela V-REP, foi possível implementar interfaces que utilizaram orientação visual e haptica para melhorar as capacidades de aprendizagem do operador. Uma estação de trabalho, novas formulações e ferramentas de apoio que controlam a simulação foram desenvolvidos a m de criar um controle mais intuitivo sobre a plataforma humanóide. Os operadores foram instruídos a reproduzir movimentos complexos em 3D sob diversas condições de treino (com feedback visual e haptico, apenas feedback haptico, apenas feedback visual, com ferramentas de orientação e sem orientação). O desempenho foi medido em termos de velocidade, a desvio de trajectória pretendida, a resposta à desvio e o tempo gasto para a criação do movimento. Os resultados deste estudo indicam que, com os mecanismos recém-implementadas, os operadores são capazes de ganhar o controlo sobre a plataforma humanóide dentro de um período relativamente curto de treino. Operadores submetidos a programas de orientação apresentam um período ainda mais curto de formação necessária, exibindo alto desempenho no sistema global. Estes fatos justi cam o papel da orientação haptica em adquirir memória cinestésica em sistemas DOFs elevados.
Telfer, Samantha Anne. "Fundamental study of growth of (Zn,Cd)Se on GaAs (211)B from hetero-interface to nanostructures". Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/515.
Texto completoChen, Yenan. "Advanced Multi-modal User Interfaces in 3D Computer Graphics and Virtual Reality". Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-75889.
Texto completoCoyer, Sean R. "Modulation of cell adhesion strengthening by nanoscale geometries at the adhesive interface". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34763.
Texto completoGuardingo, Melian Mireia. "Interfacial chemistry of catechol-based nanostructures". Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/317962.
Texto completoCatechols are aromatic derivatives present in a variety of environments in nature. Due to their broad physicochemical versatility, they play pivotal roles in multiple natural processes. Probably their most popular appearance is in the adhesive proteins of mussels in the form of the rare aminoacid L-DOPA, which is considered to be essential for the strong adhesion of mussels to surfaces under high humidity conditions. This phenomenon has fascinated scientists for decades and intensive research has been carried out in order to understand and mimic these systems. Furthermore, other chemical properties of catechols, such as their metal-chelating and redox behaviour have also been addressed for both fundamental understanding and practical application. In this thesis we were interested in the obtention of nanoscale catechol-based systems and the study of their properties. For that, a multidisciplinary work was carried out which included the synthesis of new organic compounds, the preparation of nanostructures and the use of advanced microscopies and lithographic techniques. The role of packing density and orientation of catechol moieties in the interfacial properties of catechol-terminated SAMs was studied at the local scale using an AFM tip or, alternatively, magnetic nanoparticles. The influence that the presence of the catechol ring has on the formation and final structure of SAMs was also addressed. On the other hand, the synthesis of catechol-based polymers in confined volumes was performed using direct-write AFM-assisted lithography. Polydopamine and coordination polymer particles were fabricated directly on surfaces by controlled delivery of their molecular precursors in the shape of femtolitre-sized droplets. With that, we demonstrated the viability of using this technique to place functional amorphous materials on specific areas of surfaces.
Dang, Quoc-Viet. "Conception et commande d'une interface haptique à retour d'effort pour la CAO". Phd thesis, Université de Valenciennes et du Hainaut-Cambresis, 2013. http://tel.archives-ouvertes.fr/tel-00985356.
Texto completoMiller, Adam Charles. "Assessment of Alternate Viscoelastic Contact Models for a Bearing Interface between an Axial Piston Pump Swash Plate and Housing". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1403274866.
Texto completoCosta, Luca. "The Force Feedback Microscope : an AFM for soft condensed matter". Phd thesis, Université de Grenoble, 2014. http://tel.archives-ouvertes.fr/tel-01063820.
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