48 research outputs found
The effect of silica fume on early hydration of white Portland cement via fast field cycling-NMR relaxometry
No full textDesign and evaluation of neuroregenerative properties of 4D hydrogel scaffolds
No full textUnderstanding and controlling the interactions that occur between cells and engineered materials (i.e. attachment-detachment, or that influence cell development, function or fate) are central challenges towards progress in the development of biomedical devices and regenerative medicine therapies. A particularly complex system to translate in vitro is that of the dorsal root ganglion (DRG), an interesting research target due to its relevance in peripheral nerve repair, and to its connection to the non-regenerative central nervous system (CNS). Severe peripheral nerve injuries have a limited regenerative capacity, with interventions typically not leading to full functional recovery. Ways to improve functional recovery include engineering devices that connect to both injured sides, having both cell growth guiding properties and a gradient contour to control the extent of cell-scaffold interactions. Direct ink writing (DIW) is prominent among fabrication techniques relevant to tissue engineering due to its versatility in terms of the range of materials that can be used and the limitless geometries that are easily programmed. This thesis describes three different in vitro systems, representing increasing functionality towards next generation 4D scaffolds for nerve reconstruction in vitro or nerve regeneration in vivo. The first takes advantage of cell-extracellular matrix interactions and presents an extracellular matrix (ECM)-mimetic surface treatment which, combined with DIW scaffolds of a wide range of geometries and a “blank-slate” hydrogel (pHEMA), leads to a means to exert control on the degree of cell-scaffold interactions, and manipulate cell culture development in 4D. The second explores a different class of scaffolds, compressively buckled mesostructures, which can be used as high-strain cellular frameworks leading to interesting cell behavior depending on scaffold strain and geometric aspect ratio. Further, this approach allows for the incorporation of increased functionality into these mesostructures, as they can function as electronic scaffolds for stimulation and recording of action potentials from DRG cells. Finally, the third approach combines efforts of the first two projects, building upon the ink and surface chemistries explored in the first, and the geometries explored in the second, adding a bioactive inorganic composite to create selectively growth compliant scaffolds that generate a hierarchal reorganization of DRG cells in culture mimicking that of a nerve. With the possibility of extending the complexity of these scaffolds by including controlled degradation, this last approach provides important guidelines to developing effective 4D scaffolds for nerve regeneration.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2019-12-01The student, Adina Badea, accepted the attached license on 2017-12-04 at 16:17.The student, Adina Badea, submitted this Dissertation for approval on 2017-12-04 at 16:38.This Dissertation was approved for publication on 2017-12-08 at 12:29.DSpace SAF Submission Ingestion Package generated from Vireo submission #11838 on 2019-08-22 at 16:17:41Made available in DSpace on 2019-08-23T20:44:17Z (GMT). No. of bitstreams: 6
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B.1 Programming mechanical and physicochemical properties of 3D hydrogel cellular microcultures via direct ink writing.pdf: 7230067 bytes, checksum: 0d564f61b0ffc65a1ee5ba0500c6a4eb (MD5)
B.2 Quantitative reflection imaging for the morphology and dynamics of live Aplysia californica pedal ganglion neurons cultured on nanostructured plasmonic crystals.pdf: 1232215 bytes, checksum: 42fd3a0f4b98ccc9affdea3e7bd18bc8 (MD5)
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Previous issue date: 2017-12-08Embargo set by: Seth Robbins for item 112232
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Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112232
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La traduction n’est pas qu’une traduction. Quelques propos sur la traduction d’une écriture fragmentaire bilingue: <i>Cuvântul nisiparniţă</i> (<i>Le Mot sablier</i>) de Dumitru Tsepeneag
No full textAbstract
Translation is not mere translation. A few remarks on the translation of a fragmentary bilingual text: Cuvântul nisiparniță (Le Mot sablier/The Hourglass Word) by Dumitru Tsepeneag
The present paper will focus on the translation of a fragmentary bilingual writing. Interested both in his own monolingualism and in the monolingualism of the other (see Derrida 1996, and here mainly the monolingualism of the French reader who should constitute a kind of pseudo-source-audience3), Dumitru Tsepeneag turns his own bilingualism into a topic in his book Cuvîntul nisiparniță (published first in translation as Le Mot sablier in 1984). “This (im)possible appropriation becomes the generating reason of the creation and in the creation, then in the self-translation”; a “writing experience” where the writer cultivates his bilingualism and his biculturalism, and sheds light on the process of translation from a perspective that is at least double: that of the translated42 and self-translated writer, but also that of the translator-writer” (Lungu-Badea 2008, 20). What translation strategy would be appropriate for a book that begins in Romanian and ends in French? We could claim that its destiny is to show how one language replaces another and, consequently, renders translation useless for bilingual users. If this is but an argument for the counter-translation, the French translation, published by the P.O.L. publishing house, does not challenge it. It could respect neither “the psychological intention of the author” (Ladmiral 2006, 140), nor the “semantic intention of the text” (Ladmiral and Lipiansky 1995, 53).</jats:p
Author Correction: WDR1 is a novel EYA3 substrate and its dephosphorylation induces modifications of the cellular actin cytoskeleton
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper
Gamification: Improving Supervisory Control Performance in Highly Automated Air Traffic Control
No full textThe use of automated conflict detection and resolution tools for air traffic control seems inevitable. Air traffic controllers will then take the role of automation supervisors, a role which is generally unsuitable for humans. Gamification, the use of game elements in non-gaming contexts, shows promising results in mitigating the effects of boredom. This project presents and experimentally tests a proposed implementation of gamification within an air traffic control work environment. Fictional aircraft are superimposed among automatically controlled real traffic, thus creating fictional conflicts that need resolving. System supervisors are given the task of supervising the behaviour of a fully automated conflict detection and resolution system while routing fictional aircraft safely and efficiently through the sector, avoiding conflicts with other aircraft (both real and fictional). Experiment results show that the presence of fictional aircraft increased reported concentration levels among participants, as well as improved supervisory control performance.Aerospace Engineerin
Conflict Prevention, Detection, and Resolution in Constrained Very Low-Level Urban Airspace
No full textThe interest for using small aircraft for missions in urban airspace is growing for applications like parcel deliveries. Research shows that conventional airspace structure and conflict detection and resolution techniques are not suitable for main- taining a high level of safety in constrained urban environments, especially when aircraft are restricted to flying within the limits of the road network. The problem at hand becomes even more complex when factoring in cities with topologically organic street networks, thus increasing the probability of crossing and merging traffic flows. Preliminary results show that such networks induce the detection of false-positive conflicts when using classical state- based conflict detection, decreasing the effectiveness of conflict resolution. Velocity-obstacle based conflict resolution methods were able to improve airspace safety, but require further de- velopment in order to handle conflicts in such an unpredictable and constrained environment. Thus, the doctoral project at hand seeks to develop and research improved methods for conflict prevention, detection and resolution in constrained, urban, very low-level urban airspace.Control & Simulatio
Metropolis II: Benefits of Centralised Separation Management in High-Density Urban Airspace
No full textThe Metropolis II project aimed to study the impact of centralised separation management for urban aerial mobility. Three concepts were developed in this study: a fully centralised, strategically separated concept, a hybrid concept featuring cen- tralised strategic separation and distributed tactical separation, and a fully distributed tactical concept. A comparative simu- lation study was performed, using traffic scenarios based on predicted demand in an urban airspace in the city of Vienna. Simulations were performed with varying traffic densities and situations. Results show that the purely strategic and purely tactical strategies perform comparably in terms of safety, and that further improvements can be achieved with a combination of those strategies.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Control & Simulatio
A Tactical Conflict Resolution Method for UAVs in Geovectored Airspace
No full textIn order to enable the safe and efficient integration of Unmanned Aerial Vehicles into very low level airspace, current day research focuses on the development of new traffic services and procedures. One of these is the geovectoring protocol, which aims to reduce traffic complexity by setting limits on the allowed ground speed, course, and vertical speed. A geovector can be used to increase the capacity of an airspace by lowering the conflict rate. However, problems emerge when performing avoidance maneuvers in geovectored airspace, as the limits are ignored in this process. A powerful conflict resolution algorithm is the Modified Voltage Potential (MVP). This paper proposes an extension to the MVP algorithm, based on Velocity Obstacle theory. Making use of an alternative horizontal conflict resolution maneuver which respects the geovector, five resolution strategies are defined with different priority settings for the separate limits. The performance of these strategies is compared to pure MVP on geovector, safety, and stability measures, making use of fast-time simulations in a corridor airspace. All geovector resolution strategies show improvements on the ability to perform conflict resolution maneuvers within the geovector limits, while having marginal effects on the overall airspace safety level. It is recommended to further investigate the performance of the geovector resolution strategies for other types of airspace, to verify whether the observed reduction in conflict rate from the geovectors can be reinforced by the resolution strategies.Control & Simulatio
The role of hydrogen as a future solution to energetic and environmental problems for residential buildings
No full textMetropolis II: Investigating the Future Shape of Air Traffic Control in Highly Dense Urban Airspace
No full textMetropolis II aims to provide insights in what is needed to enable high-density urban air operations. It does this by investigating the foundation for U-space U3/U4 services. The final goal is to provide a unified approach for strategic deconfliction, tactical deconfliction, and dynamic capacity management. Highly-dense operations in constrained urban airspace will likely require a degree of complexity that does not exist in modern-day air traffic management. The expected high traffic demand will require a shared use of the airspace instead of assigning exclusive use of blocks of the airspace to some flights. A unified approach for traffic management is needed because at high-densities, airspace design, flight planning, and separation management become increasingly interdependent. Metropolis II builds upon the results of the first Metropolis project. Three concepts with a varying degree of centralisation will be compared using simulations. (1) The centralised concept will take a global approach for separation management. (2) The decentralised concept aims to give the individual agents separation responsibility. (3) The hybrid concept tries to combine a centralised strategic planning agent with a robust tactical separation strategy. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Control & Simulatio
