subject:(info eu repo classification ddc 620)

1. Landig, Andreas. Hybrid Circuit QED with Spin Qubits.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/380415

► Single photons and single electrons can be confined spatially in a solid-state device by using a millimeter-sized superconducting microwave resonator for the photons and nanoscale… (more)

▼ Single photons and single electrons can be confined spatially in a solid-state device by using a millimeter-sized superconducting microwave resonator for the photons and nanoscale electrodes to form quantum dots for the electrons. The confined electrons realize a quantum mechanical two-level system (qubit), whose dipole interaction with single photons in the resonator is studied in the field of hybrid circuit quantum electrodynamics (hybrid circuit QED). These studies aim at investigating fundamental physics of quantum dots and light-matter interaction. They also work towards the realization of a scalable quantum dot based device for quantum information processing, where circuit QED is the main platform for state-of-the-art quantum information devices with superconducting qubits. So far, hybrid circuit QED studies were mainly focused on charge states in double quantum dots. In this thesis we explore hybrid circuit QED with a focus on spin states in gallium arsenide quantum dots, motivated by the potentially longer coherence time of qubits based on quantum dot spin states instead of charge states. These experiments are performed at millikelvin temperatures using an experimental setup that was in large parts designed in this work. We also advance the hybrid circuit QED device technology by developing a resonator that is magnetic field resilient and has a high characteristic impedance of the order of one kiloohm. This increases the qubit-photon coupling strength and allows for experiments in a magnetic field. In our first experiment we investigate spin states in a two-electron double quantum dot. There, the resonator acts as a spin-selective probe since it only couples with the spin-singlet states, which form a charge qubit, but is insensitive to the spin-triplet states. By probing the magnetic-field-dependent resonator transmission, we extract information about the singlet-triplet energy spectrum. In the presence of a double quantum dot voltage bias, we investigate a phenomenon called spin-blockade, which is based on a fundamental symmetry requirement for quantum states of electrons. While the qubit decoherence rate exceeds the qubit-photon coupling strength in the first experiment, the situation is reversed in our second study. There, we report strong coupling between single microwave photons and a three-electron spin-qubit, called resonant exchange (RX) qubit. We resolve the vacuum Rabi mode splitting, which is the experimental signature of strong coupling, with a coupling strength of 31MHz and a qubit decoherence rate of 20MHz. We tune both quantities electrostatically and obtain a minimal decoherence rate of 10MHz for 23MHz of coupling strength. The demonstration of strong spin-photon interaction is an important step towards long-range qubit-qubit interaction that involves spin qubits, which is realized in our third experiment. There, we implement a coherent link that controllably couples a RX qubit and a superconducting transmon qubit on the same device over a distance that is several orders of magnitude… Advisors/Committee Members: Ensslin, Klaus, id_orcid0000-0001-7007-6949, Burkard, Guido, Ihn, Thomas Markus, id_orcid0000-0002-5587-6953, Wallraff, Andreas.

Subjects/Keywords: info:eu-repo/classification/ddc/530; info:eu-repo/classification/ddc/620; Physics; Engineering & allied operations

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APA (6^th Edition):

Landig, A. (2019). Hybrid Circuit QED with Spin Qubits. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/380415

Chicago Manual of Style (16^th Edition):

Landig, Andreas. “Hybrid Circuit QED with Spin Qubits.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/380415.

MLA Handbook (7^th Edition):

Landig, Andreas. “Hybrid Circuit QED with Spin Qubits.” 2019. Web. 04 Mar 2021.

Vancouver:

Landig A. Hybrid Circuit QED with Spin Qubits. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/380415.

Council of Science Editors:

Landig A. Hybrid Circuit QED with Spin Qubits. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/380415

ETH Zürich

2. Bürki, Mathias. Efficient Visual Localization for Ground Vehicles in Outdoor Environments.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/372042

► Visual (self)localization enables Autonomous Ground Vehicles (AGVs) to assess their position and orientation within an environment with up to centimeter level accuracy, using only cost-effective… (more)

▼ Visual (self)localization enables Autonomous Ground Vehicles (AGVs) to assess their position and orientation within an environment with up to centimeter level accuracy, using only cost-effective camera sensors. Especially for high precision maneuvering in GNSS-denied environments, using cameras for localization may be the best suited option for budget- or weight constrained platforms. However, particularly in outdoor environments, camera images are subject to various forms of appearance change. This renders it challenging to reliably localize a vehicle against a map previously built from sensor data recorded under different appearance conditions. A powerful approach to deal with these appearance changes is to enhance the map with visual data from several recordings, each collected under different appearance conditions. The amount of data generated following this approach, however, scales with the number of recordings collected over time, and thus unveils a need for smart algorithms managing this data and ensuring efficient use of computation, storage and network bandwidth resources. The contributions of this thesis are centered around the research questions addressing this need for a resource-efficient and reliable visual localization system for AGVs in outdoor environments. In Part A, we propose an algorithm to dynamically select small amounts of map data matching the current appearance condition, thereby lowering network bandwidth consumption, and reducing computational demands on the vehicle platforms. We show that exploiting co-observability statistics allows for performing this appearance-based map data selection in a highly effective manner, without the need to explicitly model or enumerate the different appearance conditions. Part B is devoted to the development of a practical map management process for a visual localization system targeted at long-term use. Our experiments have revealed that multi-session maps converge to a relatively stable state after several months of collecting recordings under varying appearance conditions. Furthermore, through a tight integration of appearance-based map data selection with offline map summerization, a completely scalable visual localization and mapping framework is reached that can be used for indefinite periods of time. In Part C, we present the visual localization system developed within the UP-Drive project 1 for autonomous cars in urban outdoor environments. Thereby, a special focus has been placed on robustness against outdoor and long-term ap- pearance change, and on a careful evaluation of the localization accuracy. We demonstrate that reliable and accurate visual localization is feasible in structured outdoor environments, even over long time spans, across vastly different seasonal, weather, and lighting conditions including at night-time, and with local point features with binary descriptors on a CPU-only computer architecture. Advisors/Committee Members: Siegwart, Roland, Tardós, Juan.

Subjects/Keywords: info:eu-repo/classification/ddc/621.3; info:eu-repo/classification/ddc/620; Electric engineering; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bürki, M. (2019). Efficient Visual Localization for Ground Vehicles in Outdoor Environments. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/372042

Chicago Manual of Style (16^th Edition):

Bürki, Mathias. “Efficient Visual Localization for Ground Vehicles in Outdoor Environments.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/372042.

MLA Handbook (7^th Edition):

Bürki, Mathias. “Efficient Visual Localization for Ground Vehicles in Outdoor Environments.” 2019. Web. 04 Mar 2021.

Vancouver:

Bürki M. Efficient Visual Localization for Ground Vehicles in Outdoor Environments. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/372042.

Council of Science Editors:

Bürki M. Efficient Visual Localization for Ground Vehicles in Outdoor Environments. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/372042

ETH Zürich

3. Bösch, Patrick M. Autonomous Vehicles - The next Revolution in Mobility.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/296870

► Autonomous vehicles (AVs), also called driverless vehicles, according to SAE International (2016) levels 4 and 5 definitions, are the next revolution in transport. This thesis… (more)

▼ Autonomous vehicles (AVs), also called driverless vehicles, according to SAE International (2016) levels 4 and 5 definitions, are the next revolution in transport. This thesis provides an overview of the technology and the effects of AVs on the future transport system. It results in recommendations on how to maximize the benefits of AVs while minimizing their negative effects. It consolidates work by the author and collaborators done over the past years and therefore approaches the topic from different angles. This work thus not only provides a solid background on the topic for interested readers, but also recommendations relevant for future political discussions and practice. The first part of this thesis (Chapter 2) provides a general and qualitative overview of AVs. It investigates their effects on and potential benefits for the future transport system. This summary covers most aspects that have been topic of discussions on AVs in recent time. It presents the potential benefits of AVs, which are, for example, improved safety, fewer externalities, increased road capacity, productive drive time, and the potential for empty rides, which allow for new services and usage-patterns. But it also shows the remaining challenges for a successful release of the technology, which are, for example, technological problems, safety and security issues, data and privacy questions, as well as ethical and legal discussions. The second part (Chapter 3) approaches the topic from an economic point of view. It focuses on the future cost structure of a transport system with AVs. In a rigorous bottom-up approach, the cost and price of private, shared, and public modes are calculated. The resulting picture indicates that the reign of the private car might not yet end with the automation of transport. Shared AVs (SAVs) will likely be cheaper per passenger kilometer (PKM) and more comfortable to use. But the price difference (urban setting: private car 0.47 Swiss francs (CHF) per PKM versus SAV 0.43 CHF/PKM) might not be enough to offset the luxury of having a private mobility robot at one’s service at all times, the emotional connection to the private car, and its use as an extended part of home. The presented work also indicates that automation represents a challenge for mass transit. In dense urban cores, the limited road capacity will likely prevent alternative solutions to mass transit. Outside, where road capacity is less of an issue, however, SAVs will be a competitive alternative form of public transport. At lower prices (regional setting: SAV 0.34 CHF/PKM versus autonomous bus 0.42 CHF/PKM), SAVs enable direct on-demand door-to-door service without transfers and without strangers in the same vehicle. The third part (Chapter 4 to Chapter 7) combines the qualitative overview with the economic analysis in a simulation study of the future transport system. With a scenario-based approach using a MATSim (Horni et al., 2016) simulation of Zug, Switzerland, it approaches the topic from a policy-oriented angle. By analyzing different… Advisors/Committee Members: Axhausen, Kay W., id_orcid0000-0003-3331-1318, Kockelman, Kara M., Ciari, Francesco.

Subjects/Keywords: info:eu-repo/classification/ddc/624; info:eu-repo/classification/ddc/620; Civil engineering; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bösch, P. M. (2018). Autonomous Vehicles - The next Revolution in Mobility. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/296870

Chicago Manual of Style (16^th Edition):

Bösch, Patrick M. “Autonomous Vehicles - The next Revolution in Mobility.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/296870.

MLA Handbook (7^th Edition):

Bösch, Patrick M. “Autonomous Vehicles - The next Revolution in Mobility.” 2018. Web. 04 Mar 2021.

Vancouver:

Bösch PM. Autonomous Vehicles - The next Revolution in Mobility. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/296870.

Council of Science Editors:

Bösch PM. Autonomous Vehicles - The next Revolution in Mobility. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/296870

ETH Zürich

4. Passiu, Cristiana. XPS and DFT Investigation of the Au-S Interface.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/335671

► Self-assembled monolayers (SAMs) are semi-crystalline 2D-structures that can form spontaneously when organic molecules are adsorbed on solid or liquid substrates. The molecules that form SAMs… (more)

▼ Self-assembled monolayers (SAMs) are semi-crystalline 2D-structures that can form spontaneously when organic molecules are adsorbed on solid or liquid substrates. The molecules that form SAMs are characterized by an “anchoring” functional group, with specific affinity for the substrate, by a carbon chain that is responsible for the long-range ordering of the monolayer, thanks to van der Waals interactions, and by a tail group, which is exposed to the external environment. The relevance of SAMs for technological and industrial applications resides in their ease of preparation combined with the possibility they offer to tailor the properties of a surface in a controlled manner. After SAM formation, indeed, the surface properties will depend on the SAM structure and composition. For example, the surface wettability, adhesion, and protein-affinity will only depend on the chemistry of the functional group of the adsorbed molecules that is exposed to the environment. Electrical properties will depend on the molecular structure and on the way they are bound to the substrate. In the last decades, one of the most studied SAMs systems has been that formed by alkanethiols on gold, due to its ease of preparation and stability. Despite the great knowledge acquired for this system about its formation mechanism, its crystalline structure, and most of its physical-chemical properties, there is still a lack of knowledge about the geometry of its gold/sulfur interface. Being able to determine the interface geometry in a specific system, or to predict such geometry as a function of the employed molecules, would be useful for various applications. However, experimental studies have not yet been able to identify this geometry, due to the interface being not directly observable, nor have theoretical calculations managed to simulate the SAM formation so as to determine the energetically favored structures, due to the system complexity. One objective of this thesis was to develop a method for studying the gold/sulfur interface geometry, by employing density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) measurements. XPS is able to detect small shifts in the energy of core-level electrons of the elements present in the top few nanometers of a sample, while DFT calculations can predict such shifts. In this thesis, it was predicted by DFT that the electrons of gold atoms at the gold/sulfur interface would have slightly different binding energies than bulk atoms, and that such binding-energy shifts would be different for different geometries. This might allow the geometry identification based on the experimentally measured shifts. Another objective was the optimization of the experimental conditions for accurately measuring the binding-energy shifts. To do so, bare gold films of different thickness and surface roughness were prepared and analyzed by XPS, and different measurement parameters were tested. The results were evaluated based on the relative intensity of surface components in the main gold… Advisors/Committee Members: Spencer, Nicholas D., Rossi, Antonella, Tysoe, Wilfred T..

Subjects/Keywords: info:eu-repo/classification/ddc/540; info:eu-repo/classification/ddc/620; Chemistry; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Passiu, C. (2019). XPS and DFT Investigation of the Au-S Interface. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/335671

Chicago Manual of Style (16^th Edition):

Passiu, Cristiana. “XPS and DFT Investigation of the Au-S Interface.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/335671.

MLA Handbook (7^th Edition):

Passiu, Cristiana. “XPS and DFT Investigation of the Au-S Interface.” 2019. Web. 04 Mar 2021.

Vancouver:

Passiu C. XPS and DFT Investigation of the Au-S Interface. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/335671.

Council of Science Editors:

Passiu C. XPS and DFT Investigation of the Au-S Interface. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/335671

ETH Zürich

5. Li, Bing. Assessment of Cascading Failures Risks and Development of Mitigation Strategies.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/268045

► The reliability of electric transmission systems is challenged by the recent deployment of intermittent energy sources and market developments, which have resulted in a large… (more)

▼ The reliability of electric transmission systems is challenged by the recent deployment of intermittent energy sources and market developments, which have resulted in a large amount of power volumes being transmitted over long distance and higher uncertainty in the system operation. Wide-area blackouts and cascading events in the past decades suggest that the system is operating with reduced safety margins. Although such large blackouts are rare events, they have the potential to result in massive disruptions of the electricity service. This dissertation focuses on the estimation and quantification of the vulnerabilities and risk of cascading failures in the power systems and on the interdependent infrastructures. To this aim, the original research activities include the development and validation of computational tools for analyzing and simulating the failure behavior in power systems, the evaluation of protective measures for mitigating the cascading failures and the quantification of the impact of the interdependent infrastructures and of economic operations on the security of the power grid. In the first part of the thesis, we focus on the development of cascading failure analysis models. A DC power flow based cascading failure analysis is introduced, the linear nature of DC power flow leads to efficient computation and applicability to large-scale systems. The model considers the most common failure propagation mechanism, i.e., a cascade of overloaded lines, and the automatic system interventions such as frequency control. The voltage profile of buses and reactive power have significant impacts on the system conditions, and by disregarding their effects, the underlying assumptions in the DC power flow method may provide overly optimistic results and underestimate the risk of cascading failures. To cope with that, an advanced AC power flow cascading failure model is developed. It captures the voltage and reactive power problems in the cascade and implements the remedial actions such as under frequency load shedding. To find a compromise solution between the computationally expensive AC power flow and the approximate DC power flow, a linear implicit AC power flow method is applied in the cascading failure analysis. Statistical comparisons demonstrate that linear AC power flow provides a good approximation of the AC power flow solution and its computational time does not increase significantly compared to the DC power flow. In the cascading failure analysis, many parameters are involved. It is critical that these parameters are calibrated appropriately when the analysis is applied to a specific system. Therefore, an algorithm is developed for the calibration and the validation of the cascading failure analysis based on meta-heuristic optimization. The model parameters are optimized through minimizing the differences between the simulation results and the historical blackout data. The calibrated model is able to capture the important statistical features of cascading failures, e.g., the distribution of blackout… Advisors/Committee Members: Sansavini, Giovanni, Hug, Gabriela, Dobson, Ian.

Subjects/Keywords: info:eu-repo/classification/ddc/621.3; info:eu-repo/classification/ddc/620; Electric engineering; Engineering & allied operations

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APA (6^th Edition):

Li, B. (2018). Assessment of Cascading Failures Risks and Development of Mitigation Strategies. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/268045

Chicago Manual of Style (16^th Edition):

Li, Bing. “Assessment of Cascading Failures Risks and Development of Mitigation Strategies.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/268045.

MLA Handbook (7^th Edition):

Li, Bing. “Assessment of Cascading Failures Risks and Development of Mitigation Strategies.” 2018. Web. 04 Mar 2021.

Vancouver:

Li B. Assessment of Cascading Failures Risks and Development of Mitigation Strategies. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/268045.

Council of Science Editors:

Li B. Assessment of Cascading Failures Risks and Development of Mitigation Strategies. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/268045

6. Donnelly, Claire. Hard X-ray Tomography of Three Dimensional Magnetic Structures.

Degree: 2017, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/213985

► Three dimensional magnetic systems promise significant opportunities for applications, for example providing higher density data storage devices and new functionality associated with complex topology and… (more)

▼ Three dimensional magnetic systems promise significant opportunities for applications, for example providing higher density data storage devices and new functionality associated with complex topology and greater degrees of freedom. The aim of this thesis is to address two main challenges concerning the experimental investigation of three dimensional magnetic structures, namely the fabrication of three dimensional tailored architectures, and the characterisation of three dimensional magnetisation vector fields. The fabrication of three dimensional magnetic structures of arbitrary design was addressed, which provides progress towards achieving three dimensional magnetic systems with controllable properties. In this thesis, a 6 µm diameter artificial buckyball structure, consisting of a polymer scaffold, was fabricated using two photon lithography and subsequently coated with a magnetic material. The coating was first achieved with sputtering, and a full structural and elemental characterisation was performed with hard X-ray resonant phase tomography with a spatial resolution of 25 nm, revealing shadowing of the deposition process, as well as providing information on the electronic state of the magnetic material. An optimised deposition of the magnetic material on the polymer scaffold, with which such shadowing effects could be avoided, was achieved with a combination of atomic layer deposition and electrodeposition. Preliminary measurements of the magnetic properties of the three dimensional magnetic structure gave an indication of the influence of the physical structure on the magnetic properties. For the determination of the magnetic configuration in a three dimensional system, an appropriate imaging technique was required. Up to now, high spatial resolution three dimensional magnetic imaging has been achieved with soft X-ray and electron techniques, which are suitable for the investigation of thin film systems of total thickness up to around 200 nm. However, it has not been possible to determine the internal magnetic nanostructure within larger systems. In this thesis, hard X-rays were chosen for magnetic tomography due to their high penetration depth, which comes at the price of a low magnetic signal. To achieve hard X-ray magnetic tomography, progress was first made in the experimental capabilities required for the imaging of tomographic projections. In particular, two dimensional hard X-ray magnetic imaging at the nanoscale was developed with dichroic ptychography. In a proof of principle measurement, the magnetic configuration of a 1 µm-thick FeGd i multilayer film was imaged with a spatial resolution of 45 nm, and the optimal imaging conditions determined. Next, a reconstruction algorithm was required to obtain the three dimensional magnetic vector field, for which an iterative gradient-based optimisation routine was developed. The validity of the reconstruction was demonstrated with numerical simulations for a variety of magnetic structures. Finally, the high spatial resolution magnetic imaging with… Advisors/Committee Members: Heyderman, Laura J., Fiebig, Manfred, Eisebitt, Stefan.

Subjects/Keywords: info:eu-repo/classification/ddc/620; info:eu-repo/classification/ddc/530; Engineering & allied operations; Physics

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APA (6^th Edition):

Donnelly, C. (2017). Hard X-ray Tomography of Three Dimensional Magnetic Structures. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/213985

Chicago Manual of Style (16^th Edition):

Donnelly, Claire. “Hard X-ray Tomography of Three Dimensional Magnetic Structures.” 2017. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/213985.

MLA Handbook (7^th Edition):

Donnelly, Claire. “Hard X-ray Tomography of Three Dimensional Magnetic Structures.” 2017. Web. 04 Mar 2021.

Vancouver:

Donnelly C. Hard X-ray Tomography of Three Dimensional Magnetic Structures. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/213985.

Council of Science Editors:

Donnelly C. Hard X-ray Tomography of Three Dimensional Magnetic Structures. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/213985

ETH Zürich

7. Harmanci, Yunus Emre. Long-Term Resistance of Gradient Anchorage for Prestressed CFRP Strips in Structural Concrete Retrofitting.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/329987

► The growth in urbanized world population and higher rates of mobilization impose an increased demand on the performance of civil infrastructures such as bridges, that… (more)

▼ The growth in urbanized world population and higher rates of mobilization impose an increased demand on the performance of civil infrastructures such as bridges, that suffer not only from increased traffic loading, but also from age- and environment-related deterioration. Considerable attention was given to strengthening methods for reinforced concrete (RC) infrastructures using externally bonded reinforcements (EBR) such as carbon fiber reinforced polymers (CFRP). Their main advantages such as high strength-to-weight ratio, corrosion resistance and ease of handling have rendered them a popular choice. CFRP strips can be employed in unstressed and prestressed configurations, where recently the latter has gained considerable attention due to higher utilization of the strip's full strength capacity. Prestressing forces at both strip-ends need to be transferred into the concrete, which necessitates the use of an anchorage system. The majority of commercial products currently rely on a mechanical solution. A non-mechanical alternative is the so-called gradient anchorage, developed at Empa. It relies on the accelerated curing property of epoxy under higher temperatures and segment-wise force releasing at both strip-ends. This technique was tested extensively and proven to be suitable for strengthening applications in a short-term horizon. Long-term durability aspects of such a system is of paramount interest due to the fact that the mentioned anchorage technique purely relies on the bond behaviour between its constituents. Knowledge on the long-term behaviour is vital not only to ensure safe design but also for a broader industry acceptance. The aim of this work is to investigate the long-term performance of prestressed EBR, anchored with the gradient method, from an experimental and numerical point-of-view. For this purpose, a series of lap-shear tests were performed on concrete blocks using prestressed CFRP strips, anchored with the non-mechanical gradient technique via prestress force-releasing. Prior to lap-shear testing, specimens were exposed to various accelerated ageing conditions such as concrete carbonation, freeze-thaw-cycles (FTC), constant high humidity and temperature (below the glass transition temperature), as well as their combination. The effect of prestressing on the long-term performance is also investigated by means of exposing unstressed specimens to FTC and subsequently testing them in the identical lap-shear test setup. 3D-digital image correlation measurements were utilized during prestress force-releasing and lap-shear tests in order to obtain full-field displacements. In addition to strengthened blocks, individual material tests were performed in parallel to characterize the isolated deterioration process of concrete and epoxy. For concrete, compression tests on cubes, double punch tests on cylinders and single-edge notched bending tests on prisms were conducted. Direct tensile tests on dog-bone specimens and differential scanning calorimetry on small samples were performed for the epoxy… Advisors/Committee Members: Chatzi, Eleni, id_orcid0000-0002-6870-240X, Michels, Julien, Sena-Cruz, José, Al-Mahaidi, Riadh.

Subjects/Keywords: info:eu-repo/classification/ddc/690; info:eu-repo/classification/ddc/620; Buildings; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Harmanci, Y. E. (2018). Long-Term Resistance of Gradient Anchorage for Prestressed CFRP Strips in Structural Concrete Retrofitting. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/329987

Chicago Manual of Style (16^th Edition):

Harmanci, Yunus Emre. “Long-Term Resistance of Gradient Anchorage for Prestressed CFRP Strips in Structural Concrete Retrofitting.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/329987.

MLA Handbook (7^th Edition):

Harmanci, Yunus Emre. “Long-Term Resistance of Gradient Anchorage for Prestressed CFRP Strips in Structural Concrete Retrofitting.” 2018. Web. 04 Mar 2021.

Vancouver:

Harmanci YE. Long-Term Resistance of Gradient Anchorage for Prestressed CFRP Strips in Structural Concrete Retrofitting. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/329987.

Council of Science Editors:

Harmanci YE. Long-Term Resistance of Gradient Anchorage for Prestressed CFRP Strips in Structural Concrete Retrofitting. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/329987

8. Loiseau, Eve. Magnetically Triggered Release of Active Molecules in Construction Materials Using Capsules Made by Microfluidic Technology.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/334675

► Encapsulation systems for the on-demand release of cargo molecules find applications in several fields, ranging from agricultural and construction to pharmaceuticals, food and materials science.… (more)

▼ Encapsulation systems for the on-demand release of cargo molecules find applications in several fields, ranging from agricultural and construction to pharmaceuticals, food and materials science. In the construction sector, encapsulation systems have been used in the form of phase change materials for smart insulation of buildings and have recently been envisioned as a possible approach to deliberately control the setting reaction of cementitious materials. Controlling the setting of cement in building materials is crucial to prevent losses and high costs associated with early or late hardening of concretes and mortars. Current solutions are not satisfactory because accelerators and retarder molecules cannot be activated on demand in a homogeneous manner throughout the cementitious material. In this thesis, encapsulation systems for the on-demand release of molecules in cementitious materials are designed and investigated. On-demand release is triggered remotely using an external alternating magnetic field to locally heat the microcapsules. Heating leads to capsule bursting and local release of cargo molecules. Microcapsules with such thermally-triggered response were produced from double emulsions templates made in glass capillary microfluidic devices. The middle oil phase of the water-oil-water double emulsion contains a mixture of monomers, photoinitiator and inert liquids, which can be polymerized under UV light to generate monodisperse capsules with microstructured shells. The shell microstructure is determined by the phase separation of the polymer from the inert diluent during conversion of the double emulsion into microcapsules. The composition of the Summary ii oil phase directly impacts the size of polymerized particles formed within the shell, providing a useful control parameter to tune the mechanical properties of the microcapsules. Interestingly, the use of an amphiphilic inert liquid such as undecanol enables the formation of shells with open pores upon removal of the liquid. By contrast, microstructured shells with a polymer skin in the outer and inner walls are generated if the inert liquid displays no surface activity. This leads to the entrapment of the liquid inside the shell. If a volatile inert liquid is used, local heating of the microcapsule in an alternating magnetic field causes bursting and release of the cargo molecules encapsulated in the core. To ensure local heating of the capsules without an undesirable increase of the temperature of the surrounding cementitious paste, millimeter-sized metal spheres are used as inductive heat sources. In this approach, the metal spheres are coated with the thermo-sensitive microcapsules to generate a raspberry-like encapsulation system that can be activated using an external magnetic field. Experimental results obtained using such model raspberry-like system demonstrate that this is a feasible strategy to enable the on-demand release of an accelerator compound in an aqueous medium. The use of metallic fibers already used in concrete formulations as heat… Advisors/Committee Members: Studart, André R., Vermant, Jan, Creton, Costantino.

Subjects/Keywords: microfluidics; info:eu-repo/classification/ddc/690; info:eu-repo/classification/ddc/620; Buildings; Engineering & allied operations

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APA (6^th Edition):

Loiseau, E. (2018). Magnetically Triggered Release of Active Molecules in Construction Materials Using Capsules Made by Microfluidic Technology. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/334675

Chicago Manual of Style (16^th Edition):

Loiseau, Eve. “Magnetically Triggered Release of Active Molecules in Construction Materials Using Capsules Made by Microfluidic Technology.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/334675.

MLA Handbook (7^th Edition):

Loiseau, Eve. “Magnetically Triggered Release of Active Molecules in Construction Materials Using Capsules Made by Microfluidic Technology.” 2018. Web. 04 Mar 2021.

Vancouver:

Loiseau E. Magnetically Triggered Release of Active Molecules in Construction Materials Using Capsules Made by Microfluidic Technology. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/334675.

Council of Science Editors:

Loiseau E. Magnetically Triggered Release of Active Molecules in Construction Materials Using Capsules Made by Microfluidic Technology. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/334675

ETH Zürich

9. Tzschaschel, Christian. Coherent spin dynamics in optically excited antiferromagnets.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/379113

► Antiferromagnetic spintronics emerged in the last decade as a promising approach to overcome limitations of current information technology. Owing to the vanishing net magnetization, antiferromagnetic… (more)

▼ Antiferromagnetic spintronics emerged in the last decade as a promising approach to overcome limitations of current information technology. Owing to the vanishing net magnetization, antiferromagnetic materials exhibit spin dynamics on sub-picosecond timescales potentially allowing not only for data storage and logic circuit applications that are orders of magnitude faster than their established ferromagnetic counterparts, but also the development of new paradigms for device architectures with greater functionality. Due to a tremendous interest in the realization of antiferromagnet-based devices, the tools for the ultrafast control and manipulation of antiferromagnets are currently being explored. In the current thesis, we use time-resolved optical experiments to unravel the coherent spin dynamics in antiferromagnets on their intrinsic timescales. Three consecutive projects form the cornerstones of the present cumulative thesis. In the first project, we achieved for the first time the experimental discrimination of different spin excitation mechanisms. The fundamental understanding of the relevant excitation mechanism constitutes an unprecedented degree of optical control of antiferromagnets. The second project is concerned with probing antiferromagnetic spin dynamics. We show that time-resolved measurements of optical second-harmonic generation provide quantitative access directly to the antiferromagnetic order parameter. In combination with established magneto-optical probes, we track the motion of an antiferromagnetic order parameter in three dimensions. We find that the spin precession during an antiferromagnetic resonance exhibits a pronounced ellipticity, which opens up new routes for the energy efficient control of antiferromagnetic order. Lastly, we show that spin damping during the optical excitation gives rise to an optically induced ferromagnetic spin canting in otherwise fully compensated antiferromagnets. We show that this process, which has so far been neglected for ultrafast optical excitations, can be the dominant spin excitation mechanism in antiferromagnets. The results of this thesis provide new insights into the optical control and manipulation of antiferromagnets. These key findings are crucial for the development of future antiferromagnetic spintronic devices. Beyond academic research, the present thesis also constitutes an educational advancement. In an effort to improve our capabilities of teaching X-ray diffraction techniques to undergraduate students, an intuitive and flexible device is presented in the appendix. Advisors/Committee Members: Fiebig, Manfred, Satoh, Takuya, Johnson, Steven, id_orcid0000-0001-6074-4894.

Subjects/Keywords: info:eu-repo/classification/ddc/530; info:eu-repo/classification/ddc/620; Physics; Engineering & allied operations

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APA (6^th Edition):

Tzschaschel, C. (2019). Coherent spin dynamics in optically excited antiferromagnets. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/379113

Chicago Manual of Style (16^th Edition):

Tzschaschel, Christian. “Coherent spin dynamics in optically excited antiferromagnets.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/379113.

MLA Handbook (7^th Edition):

Tzschaschel, Christian. “Coherent spin dynamics in optically excited antiferromagnets.” 2019. Web. 04 Mar 2021.

Vancouver:

Tzschaschel C. Coherent spin dynamics in optically excited antiferromagnets. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/379113.

Council of Science Editors:

Tzschaschel C. Coherent spin dynamics in optically excited antiferromagnets. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/379113

ETH Zürich

10. Yazdani, Nuri. Carrier Dynamics in Nanocrystals and Nanocrystal Solids: Experiment and Simulation.

Degree: 2017, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/219042

► Films of semiconductor nanocrystals (NC-solids) hold great promise as low-cost, solution-processable semiconductors with electronic and optical properties that can be tuned by varying the size… (more)

▼ Films of semiconductor nanocrystals (NC-solids) hold great promise as low-cost, solution-processable semiconductors with electronic and optical properties that can be tuned by varying the size and composition of the constituent nanocrystals (NCs), as well as their surfaceterminating ligands. Further increase in the performance parameters of devices incorporating NC-solids will require a robust understanding of the effects of the composition, size, and surface termination of the individual NCs, on the charge carrier dynamics resulting from their assembly into densely packed films. Here we investigate the phononic structure of the NCs, the resulting electron-phonon interactions, and their influence on charge carrier transport in NC-solids. We choose lead sulfide (PbS) NCs as a model system, due to the extensive literature and their use in a wide range of applications from LEDs, photodetectors, solar cells, and thermoelectrics. Knowledge of the phononic properties of NCs, and how the phonons couple to the electronic states of the NCs is crucial for understanding energy gain, loss, and transport processes in NC-solids. Using inelastic neutron scattering measurements and Ab-Initio Molecular Dynamics (AIMD) simulations, we quantify the phonon density of states of nano-sized crystallites as a function of crystallite size. We demonstrate that the mechanical softening of the surface of nanocrystalline domains results in low and high energy phonon modes with reduced symmetry and large thermal displacements. Using simulation, we show that these modes couple strongly to the electronic states in NCs, and cause strong thermal broadening of optical transitions and efficient phonon-mediated electronic transitions, effects which have been observed experimentally. We study the impact of thiol versus halide terminations of the NC surface, and demonstrate that the electron-phonon coupling in the NCs can be tuned through the choice of surface termination. To investigate charge carrier transport in NC-solids, we perform Time of Flight (TOF) photocurrent transient measurements on PbS NC-solids. The TOF technique provides a robust approach to probe carrier dynamics in disordered, low-mobility materials. We find that the carrier mobility extracted via TOF in NC-solids is temperature activated, and that both the activation energy and temperature independent prefactor of the carrier mobility scale strongly with NC size. Our analysis indicates that the distribution of carrier hopping times is power-law distributed with divergent mean values. This is characteristic of disordered solids and explains our finding that the extracted carrier mobilities from TOF depend on the device thickness. Indeed, this implies that the series resistance will depend superlinearly on the device thickness. Finally, we motivate a model for charge carrier transport in NCsolids based on phonon-mediated electron transfer. Using AIMD, we calculate the wavefunction overlap between neighboring NC and the reorganization energies… Advisors/Committee Members: Wood, Vanessa, id_orcid0000-0001-6435-0227, Norris, David J., Bona, Gian Luca.

Subjects/Keywords: info:eu-repo/classification/ddc/621.3; info:eu-repo/classification/ddc/620; info:eu-repo/classification/ddc/530; Electric engineering; Engineering & allied operations; Physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yazdani, N. (2017). Carrier Dynamics in Nanocrystals and Nanocrystal Solids: Experiment and Simulation. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/219042

Chicago Manual of Style (16^th Edition):

Yazdani, Nuri. “Carrier Dynamics in Nanocrystals and Nanocrystal Solids: Experiment and Simulation.” 2017. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/219042.

MLA Handbook (7^th Edition):

Yazdani, Nuri. “Carrier Dynamics in Nanocrystals and Nanocrystal Solids: Experiment and Simulation.” 2017. Web. 04 Mar 2021.

Vancouver:

Yazdani N. Carrier Dynamics in Nanocrystals and Nanocrystal Solids: Experiment and Simulation. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/219042.

Council of Science Editors:

Yazdani N. Carrier Dynamics in Nanocrystals and Nanocrystal Solids: Experiment and Simulation. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/219042

ETH Zürich

11. Fontana, Filippo Federico. Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/360777

► Developments in Additive Manufacturing (AM) in the last decades originated a shift from prototyping toward manufacturing applications. Through a small lot-size advantage and a complexity… (more)

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Fontana, F. F. (2019). Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/360777

Chicago Manual of Style (16^th Edition):

Fontana, Filippo Federico. “Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/360777.

MLA Handbook (7^th Edition):

Fontana, Filippo Federico. “Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation.” 2019. Web. 04 Mar 2021.

Vancouver:

Fontana FF. Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/360777.

Council of Science Editors:

Fontana FF. Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/360777

ETH Zürich

12. Chen, Mingyang. Sorption-Induced Deformation of Nanoporous Materials.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/372432

► Sorption-induced deformation is ubiquitous in nanoporous media, but underlying mechanisms are not yet fully understood, and a reliable modeling of this phenomenon is absent. Moreover… (more)

▼ Sorption-induced deformation is ubiquitous in nanoporous media, but underlying mechanisms are not yet fully understood, and a reliable modeling of this phenomenon is absent. Moreover hysteresis in sorption and swelling isotherms is observed but its origin not yet fully understood and not modeled. In this thesis the sorption-induced deformation of nanoporous media is studied systematically with different approaches. Three different nanoporous materials are considered: microporous polymers, microporous polymer-based composites and mesoporous materials. With the help of molecular simulations, the coupling mechanisms between sorption and deformation are revealed and the sorption and strain isotherms, as well as their hysteresis, are quantitatively modeled. With the knowledge gained at molecular level, a macroscopic description of sorption-induced deformation is given with the help of a dependent domain model. Molecular simulations demonstrate that microporous polymers swell upon water sorption as water molecules have a tendency to create more space between the flexible polymer chains for accommodating their presence. Sorption hysteresis is found to be related to deformation: polymers swell to form water–polymer hydrogen bonds upon adsorption but these bonds do not break upon desorption at the same chemical potential, which leads to sorption hysteresis. This hysteresis also manifests itself in other physical properties such as heat of sorption and bulk modulus. The influence of temperature and stress state on the coupled behavior is also examined. It is found that, when relating observable variables to the correct independent variables, hysteresis disappears as such explaining the actual origin of hysteresis. As a statement, hysteresis does not exist when looking at it from the correct driving potential. With the knowledge acquired on the bulk microporous polymer, the sorption-induced deformation of a microporous polymer-based composite, with cellulose nanocrystal (CN) as reinforcement and amorphous cellulose (AC) as matrix, is studied. Two competitive mechanisms are found regarding the coupling between sorption and deformation. The first mechanism is the reinforcing effect through CN-AC mechanical interaction, which constrains the sorption-induced swelling of the matrix and results in a reduction of sorption amount and of hysteresis in both sorption and deformation. The second mechanism is the CN-water interaction, enhancing water sorption in the matrix at the CN-matrix interface, increasing the sorption-induced swelling of the matrix and increasing the resulting hysteresis in sorption and deformation. Sorption-induced deformation in mesoporous materials is studied at single pore level with two atomistic models, a slit pore and a cylindrical pore. Two driving mechanisms are revealed for both slit and cylindrical pore models. At high relative vapor pressure, pore deformation is governed by Laplace pressure as the pore gets filled with liquid due to capillary condensation. At low pressure, when liquid films are… Advisors/Committee Members: Carmeliet, Jan, Vermant, Jan, Coasne, Benoit.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chen, M. (2019). Sorption-Induced Deformation of Nanoporous Materials. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/372432

Chicago Manual of Style (16^th Edition):

Chen, Mingyang. “Sorption-Induced Deformation of Nanoporous Materials.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/372432.

MLA Handbook (7^th Edition):

Chen, Mingyang. “Sorption-Induced Deformation of Nanoporous Materials.” 2019. Web. 04 Mar 2021.

Vancouver:

Chen M. Sorption-Induced Deformation of Nanoporous Materials. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/372432.

Council of Science Editors:

Chen M. Sorption-Induced Deformation of Nanoporous Materials. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/372432

ETH Zürich

13. Spierings, Adriaan Bernardus. Powder Spreadability and Characterization of Sc- and Zr-modified Aluminium Alloys processed by Selective Laser Melting: Quality Management System for additive manufacturing.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/253924

► Additive manufacturing technologies such as Selective Laser Melting have reached a level of maturity, which allows the direct production of functional parts for many industrial… (more)

▼ Additive manufacturing technologies such as Selective Laser Melting have reached a level of maturity, which allows the direct production of functional parts for many industrial applications. For certain industrial sectors such as for instance the Space-, the Aerospace- and the turbine industry, high quality requirements are put on structural parts. These requirements can address aspects of mechanical material properties, material microstructure, part- and surface quality and accuracy, respectively. However, the variety of influencing parameters in the SLM-processing chain makes it difficult to directly qualify parts for such applications, giving the need to qualify each AM-part separately after the additive build process. For this reason, a Quality Management System for Selective Laser Melting, and more generally for additive manufacturing processes, is essential. The implementation of a Statistical process control (SPC) methodology is therefore suggested, enabling the consideration of various different influencing parameters, and giving insights into the dependencies of input and output parameters, as-well as cross-correlations between different parameters. As a contribution to a Quality Management System, two influencing parameters in the SLM-process chain are investigated in more detail. Powder flowabilty is an essential parameter affecting the capability of a SLM-machine to create the thin powder layers required in a repeatable and high quality. As the traditional flowability measurement techniques, such as e.g. the Hall flow meter, are not capable of measuring flowabilty sufficiently close to the SLM-processing conditions, a new quantitative method is developed, which is based on the statistical analysis of avalanches taking place when a powder flows freely in a rotating drum. This measurement approach is closer to the conditions in a SLM-machine when powders are spread across the build platform. Therefore, the flowability measurement technique can also be considered as an assessment of the powder spreadability, and the quantitative results can be correlated with the quality of the generated powder layer. In addition, the alloy system and –composition also affects the quality of the final parts by the various metallurgical phenomena taking place when a small melt-pool cools down. A Sc- and Zr-modified 5xxx aluminium alloy powder is used to develop the basic understanding of the consolidation phenomena taking place during SLM. The evolving SLM-processed unique microstructure consists of a bi-modal grain size distribution, with grain sizes in the range of [200 nm, < 2 um] in the fine-grained area, and about [1 um, 15 um] in the coarser regions, respectively. Hence, such grain sizes are a factor of 5 to 10 smaller compared to traditional SLM-processed Al-alloys. Due to the complete absence of any preferential grain orientation in the fine-grained areas, alongside with the small grains, this alloy system shows almost no mechanical anisotropy. A further advantage of this fine-grained microstructure is a reduced… Advisors/Committee Members: Wegener, Konrad, Levy, Gideon N., Meboldt, Mirko.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Spierings, A. B. (2018). Powder Spreadability and Characterization of Sc- and Zr-modified Aluminium Alloys processed by Selective Laser Melting: Quality Management System for additive manufacturing. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/253924

Chicago Manual of Style (16^th Edition):

Spierings, Adriaan Bernardus. “Powder Spreadability and Characterization of Sc- and Zr-modified Aluminium Alloys processed by Selective Laser Melting: Quality Management System for additive manufacturing.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/253924.

MLA Handbook (7^th Edition):

Spierings, Adriaan Bernardus. “Powder Spreadability and Characterization of Sc- and Zr-modified Aluminium Alloys processed by Selective Laser Melting: Quality Management System for additive manufacturing.” 2018. Web. 04 Mar 2021.

Vancouver:

Spierings AB. Powder Spreadability and Characterization of Sc- and Zr-modified Aluminium Alloys processed by Selective Laser Melting: Quality Management System for additive manufacturing. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/253924.

Council of Science Editors:

Spierings AB. Powder Spreadability and Characterization of Sc- and Zr-modified Aluminium Alloys processed by Selective Laser Melting: Quality Management System for additive manufacturing. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/253924

ETH Zürich

14. Srna, Aleš. Experimental Characterization of Pilot-Fuel Ignition, Combustion, and Soot Formation in Dual-Fuel Combustion Systems.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/309334

► In recent years, many natural gas-fueled engine concepts have emerged for transportation, as well as stationary applications. They seem as an attractive solution to meet… (more)

▼ In recent years, many natural gas-fueled engine concepts have emerged for transportation, as well as stationary applications. They seem as an attractive solution to meet current and upcoming emission legislations at uncompromised efficiency. Furthermore, the application of natural gas is advantageous regarding the associated CO2 reduction, high resistance to auto-ignition (knock), and low sooting propensity. Especially in the large engine applications ranging from heavy-duty to marine and stationary, the lean burn combustion systems with a potential for lower pollutant emission at simultaneously higher than diesel-engine efficiencies are employed. Advanced ignition systems like pilot ignition dual-fuel or pre-chamber spark ignition are utilized to ensure stable and fast combustion. The dual-fuel combustion process is highly complex, involving short transient pilot-fuel injection into the premixed gaseous fuel charge, autoignition, and combustion mode transition into premixed flame propagation. Despite many advantages, the dual-fuel engines in gas operation often exhibit a tradeoff of either (a) higher NOx and soot emissions or (b) high unburnt hydrocarbon emissions at deteriorated thermal efficiency. This clearly elucidates the need for an improved understanding of the combustion process to support the development of advanced engine configurations and control systems, in order to achieve the design goals of fulfilling the present and future emission standards at highest possible thermal efficiency. However, fundamental investigations of the dual-fuel combustion process are scarce. The aim of this thesis was to advance the fundamental understanding of the dual-fuel combustion process. Characteristics of ignition, combustion, and the sooting propensity of a short pilot injection in compressed methane/air charge were investigated. Experiments were performed in an optically accessible Rapid Compression Expansion Machine, featuring quiescent charge throughout the cycle. A single-hole coaxial diesel injector mounted at the cylinder periphery was employed to admit the pilot fuel. The comprehensive measurement matrix includes variations of premixed charge (methane/air) equivalence ratio, pilot-fuel injection pressure and duration, as well as investigations at reduced oxygen charge content. Several cross-variations were performed. The optical diagnostics setup includes advanced laser-based as well as passive optical methods. Pilot-fuel mixing was characterized under non-reactive conditions using simultaneous quantitative high-speed tracer-PLIF, schlieren, and Mie-scattering imaging techniques. In reactive cases, the diagnostic setup featured simultaneous high-speed CH2O-PLIF imaging, OH* chemiluminescence and schlieren imaging for the detection of low-temperature and high-temperature ignition events, as well as to observe the transition into premixed flame propagation. Finally, combustion sooting propensity, as well as the combustion spectral footprint were investigated using the diffuse back-illumination and… Advisors/Committee Members: Boulouchos, Konstantinos, Bruneaux, Gilles, Herrmann, Kai.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Srna, A. (2018). Experimental Characterization of Pilot-Fuel Ignition, Combustion, and Soot Formation in Dual-Fuel Combustion Systems. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/309334

Chicago Manual of Style (16^th Edition):

Srna, Aleš. “Experimental Characterization of Pilot-Fuel Ignition, Combustion, and Soot Formation in Dual-Fuel Combustion Systems.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/309334.

MLA Handbook (7^th Edition):

Srna, Aleš. “Experimental Characterization of Pilot-Fuel Ignition, Combustion, and Soot Formation in Dual-Fuel Combustion Systems.” 2018. Web. 04 Mar 2021.

Vancouver:

Srna A. Experimental Characterization of Pilot-Fuel Ignition, Combustion, and Soot Formation in Dual-Fuel Combustion Systems. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/309334.

Council of Science Editors:

Srna A. Experimental Characterization of Pilot-Fuel Ignition, Combustion, and Soot Formation in Dual-Fuel Combustion Systems. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/309334

ETH Zürich

15. Hutter, Richard. Model-Based Analysis and Control of a Diesel-Ignited Gas Engine.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/371712

► The Diesel-ignited gas engine is a promising concept for reducing the emission of climate-damaging greenhouse gases from passenger cars. The reduction of CO2 emissions that… (more)

▼ The Diesel-ignited gas engine is a promising concept for reducing the emission of climate-damaging greenhouse gases from passenger cars. The reduction of CO2 emissions that becomes possible with this concept is a result of using an alternative fuel with increased efficiency. In the dual-fuel combustion process methane, as the primary fuel, is ignited by a small amount of Diesel. In addition to the dual-fuel combustion process, the Diesel-ignited gas engine can also be operated in pure Diesel combustion mode, like a conventional Diesel engine. While the operating strategies of conventional Diesel or gasoline engines are well known and optimized, the operation of the Diesel-ignited gas engine is still the subject of research. Specifically, the operation at low torque levels is demanding. The contradictory requirements of the two fuels lead to high raw emissions of unburnt methane. In addition, the removal of these raw emissions from the exhaust gas is difficult due to the low exhaust gas temperatures. The Diesel-ignited gas engine is thus not capable of covering low torque requirements using the dual-fuel combustion process, which is why only the transition to the conventional Diesel operation remains possible. The goal of this thesis is to describe the operational limits of the dual-fuel operation and to develop the essential operating strategies. For this purpose, the air path as well as the exhaust aftertreatment system is described by control-oriented models which are then used in numerical optimization methods. Finally, this thesis shows that the dual-fuel operation at low loads is only feasible with a dedicated control strategy that avoids the emission of unburnt methane at the tailpipe. The reaction heat originating from the conversion of carbon monoxide thereby plays an important role in the effective post-oxidation of the methane in the catalyst. Given the limited effectiveness of today’s catalyst, the stoichiometric operation, with its high raw emission of carbon monoxide, is the preferred dual-fuel strategy. For achieving torque levels beyond the operational limit of the dual-fuel combustion process, the transition to Diesel operation is crucial in terms of the practicability of this engine type. However, the transition between the combustion modes is a challenging task as various actuator settings, from both the fuel and air paths, change significantly during the transition. This thesis shows that only the optimal design of the oxygen concentration trajectories in the intake and exhaust manifolds yields a smooth transition with significant reductions of both the torque deviation and the emissions of pollutants. Advisors/Committee Members: Onder, Christopher, Rudolf von Rohr, Philipp, Eichlseder, Helmut.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Hutter, R. (2019). Model-Based Analysis and Control of a Diesel-Ignited Gas Engine. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/371712

Chicago Manual of Style (16^th Edition):

Hutter, Richard. “Model-Based Analysis and Control of a Diesel-Ignited Gas Engine.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/371712.

MLA Handbook (7^th Edition):

Hutter, Richard. “Model-Based Analysis and Control of a Diesel-Ignited Gas Engine.” 2019. Web. 04 Mar 2021.

Vancouver:

Hutter R. Model-Based Analysis and Control of a Diesel-Ignited Gas Engine. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/371712.

Council of Science Editors:

Hutter R. Model-Based Analysis and Control of a Diesel-Ignited Gas Engine. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/371712

ETH Zürich

16. Petrović, Miloš. Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/272502

► The development of the sliding-based modification method for the seismic in-plane behavior of structural unreinforced masonry (URM) walls is the objective of the present research… (more)

▼ The development of the sliding-based modification method for the seismic in-plane behavior of structural unreinforced masonry (URM) walls is the objective of the present research project. This objective is achieved by using engineered deformable (soft) layers, which are already implemented in URM walls, placed at the bottom and/or the top of the wall, however, for the sake of providing a moisture barrier in the form of a damp-proof course membrane, ensuring sound insulation or accommodating the short-term or long-term differential movements between the masonry walls and the floor and ceiling construction. After a comprehensive review of work on response of masonry walls that develop sliding, with a special attention paid to studies on the shear behavior of URM with incorporated soft layers, and after selecting the soft layers from those available on the Swiss market, an experimental investigation was conducted. The first part of the experimental investigation was aimed at providing the information on the in-plane compressive and shear behavior of masonry with a so called multi-layer bed joint, i.e. with a (core) soft layer protected by two layers of elastomer before placed in the middle of the mortar bed joint. The main reason for protecting the core soft layers was to reduce the potential cyclic shear loading-caused damage, i.e. to insure durability of the soft layer bed joint. The second part of the experimental investigation comprised a series of static-cyclic tests on full-scale structural masonry walls with a multi-layer bottom bed joint that were conducted in two phases. The preliminary phase was aimed at determining the most suitable type of core soft layer for the main testing phase. Within the main phase, the influences of the pre-compression level, the aspect ratio and the size effect on the behavior of URM walls with a multi-layer bed joint were investigated. The results obtained indicate that the load-bearing URM walls with a multi-layer bed joint, in spite of the prevailing sliding response, could exhibit a significant shear capacity, which depends on the type of core soft layer material, the applied level of pre-compression and on the loading speed. As compared to the walls without a multi-layer bed joint, URM walls with a multi-layer bed joint have a smaller initial stiffness. Importantly, the multi-layer bed joints provide a significantly large ultimate displacement capacity to the URM walls, thus modifying and improving their seismic response. The ultimate displacement capacity is, however, strongly influenced by the extent of shear cracks that develop in the wall, the occurrence of tensile cracks in the head joints at the bottom block course, and reduction of the effective area of the wall. In general, it can be concluded that multi-layer bed joints in URM walls act to modify the seismic response of URM structures and improve their seismic performance. To support design of URM walls with multi-layer bed joints, a method to construct an idealization of the horizontal force-displacement response… Advisors/Committee Members: Stojadinovic, Bozidar, id_orcid0000-0002-1713-1977, Mojsilović, Nebojša, Magenes, Guido.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Petrović, M. (2018). Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/272502

Chicago Manual of Style (16^th Edition):

Petrović, Miloš. “Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/272502.

MLA Handbook (7^th Edition):

Petrović, Miloš. “Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls.” 2018. Web. 04 Mar 2021.

Vancouver:

Petrović M. Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/272502.

Council of Science Editors:

Petrović M. Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/272502

ETH Zürich

17. Rigger, Eugen. Task Definition for Design Automation.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/382356

► Design automation has been the focus of research for more than five decades. It supports design processes in several aspects by automating design tasks based… (more)

▼ Design automation has been the focus of research for more than five decades. It supports design processes in several aspects by automating design tasks based on computational methods and tools to save time, generate alternative design solutions, explore solution spaces, and reuse engineering knowledge. Yet, the current industrial practice does not reflect the opportunities provided by state-of-the-art design automation methods. The factors contributing to this gap are: first, a lack of knowledge of design automation opportunities and insufficient support for the integration of design automation in design practice including the supporting methods and technological environments. Second, metrics and methods for comprehensive estimation of the impact of design automation implementation on design practice do not exist making it difficult to quantify the value of design automation and justify efforts for implementation. Finally, design automation applications are often perceived as black-box systems since knowledge is hard-coded in design automation applications. This also increases efforts for knowledge formalization. In response to these issues, this thesis proposes a methodology for design automation task definition that features collaborative workshops to account for the different viewpoints of designers. It builds upon a design automation task categorization that is characterized by the knowledge levels required for design automation task definition and consists of four different methods that build on each other. The first method focuses on the identification of design automation use cases. It features detailed analysis of design processes and reuse of design automation task templates to support both the identification of possible use cases and the integration of the corresponding software applications into design practice. The second method introduces a top-down derivation of metrics based on potential failure modes in design. The third method enables estimation of the impact and value of design automation implementation based on design automation task templates enabling reuse and associating metrics to design processes. Finally, design automation task formalization by designers is enabled using graphical modeling. The method supports reuse and modularization of knowledge based on the design automation task categorization. To enable reasoning in the context of the methodology, a meta-model that clarifies the vocabulary is established based on standardized languages. The proposed methodology is evaluated based on three industrial use cases that highlight the necessity to involve multiple designers for design automation task definition to account for different viewpoints for needs identification. Further, the results show the potential for design automation application in the early stages of design as well as the applicability of the proposed approach for design automation task formalization by designers. Thus, the work presented in this thesis contributes by ii introducing and evaluating a novel methodology for… Advisors/Committee Members: Shea, Kristina, Duffy, Alex, Stankovic, Tino.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Rigger, E. (2019). Task Definition for Design Automation. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/382356

Chicago Manual of Style (16^th Edition):

Rigger, Eugen. “Task Definition for Design Automation.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/382356.

MLA Handbook (7^th Edition):

Rigger, Eugen. “Task Definition for Design Automation.” 2019. Web. 04 Mar 2021.

Vancouver:

Rigger E. Task Definition for Design Automation. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/382356.

Council of Science Editors:

Rigger E. Task Definition for Design Automation. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/382356

ETH Zürich

18. Lataniotis, Christos. Data-driven uncertainty quantification for high-dimensional engineering problems.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/377865

► In the context of complex industrial systems and civil infrastructures, taking into account uncertainties during the design process has received much attention in the last… (more)

▼ In the context of complex industrial systems and civil infrastructures, taking into account uncertainties during the design process has received much attention in the last decades. Although there is significant progress in modelling such systems, there are always discrepancies between ideal in-silico designed systems and real-world manufactured ones. Starting from a realistic computational model that reproduces the behaviour of an engineering system, uncertainty quantification aims at modelling the various sources of uncertainty (including natural variability and lack of knowledge) affecting its input parameters as well as propagating these uncertainties to the response quantities of interest (e.g. performance indicators). Due to the high-fidelity and related computational costs of such models, the use of Monte Carlo methods for uncertainty quantification is often not a viable solution. To overcome this limitation, the use of surrogate models has become well established. A surrogate model is an analytical function that provides an accurate approximation of a computational model, based on a limited number of runs of the simulator at selected values of the input parameters and an appropriate learning algorithm. In this thesis, the focus is the application of modern uncertainty quantification techniques in the presence of a large number, up to several thousands, of system parameters. As the dimensionality of the input space increases, the performance of surrogate modelling methods decreases, an issue that is known as curse of dimensionality. Furthermore, we approach the problem from a purely data-driven perspective, the entire analysis needs to be conducted based only a limited number of observations and little to no assumptions about the inner workings of the system. This scenario has high practical relevance, due to complex workflows involving various software packages to simulate a system or real-world applications for which only measurements of the input parameters and model responses are available. However such data-driven approaches introduce additional challenges related to the (unknown) stochastic properties of the input space. To quantify those, one typically resorts to well-known inference techniques (discussed in Chapter 2), but such methodologies also suffer from the curse of dimensionality. To enable data-driven uncertainty quantification in high-dimensional input spaces, we propose a combination of machine learning techniques for data compression and state-of-the-art surrogate modelling introduced by the uncertainty quantification community. The first fundamental ingredient, dimensionality reduction, is discussed in Chapter 3. Through a literature review on the rather broad topic of dimensionality reduction, we highlight the strengths and weaknesses of various techniques as well as their area of application. The second fundamental ingredient, surrogate modelling, is discussed in Chapter 4. Beyond a general formulation, focus is given on two state-of-the-art techniques, namely… Advisors/Committee Members: Sudret, Bruno, id_orcid0000-0002-9501-7395, Marelli, Stefano, id_orcid0000-0002-9268-9014, Chatzi, Eleni, id_orcid0000-0002-6870-240X, Bourinet, Jean-Marc.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Lataniotis, C. (2019). Data-driven uncertainty quantification for high-dimensional engineering problems. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/377865

Chicago Manual of Style (16^th Edition):

Lataniotis, Christos. “Data-driven uncertainty quantification for high-dimensional engineering problems.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/377865.

MLA Handbook (7^th Edition):

Lataniotis, Christos. “Data-driven uncertainty quantification for high-dimensional engineering problems.” 2019. Web. 04 Mar 2021.

Vancouver:

Lataniotis C. Data-driven uncertainty quantification for high-dimensional engineering problems. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/377865.

Council of Science Editors:

Lataniotis C. Data-driven uncertainty quantification for high-dimensional engineering problems. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/377865

ETH Zürich

19. Charreyron, Samuel. Remote Magnetic Navigation and Applications in Ophthalmic Surgery.

Degree: 2020, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/431062

► Magnetism has entertained a close relationship with medicine throughout history, but its ability to navigate therapeutic devices inside the human body has emerged in the… (more)

▼ Magnetism has entertained a close relationship with medicine throughout history, but its ability to navigate therapeutic devices inside the human body has emerged in the last few decades thanks to technological improvements in the fabrication, and control of magnetic devices. Remote magnetic navigation of untethered devices, also known as micro or nanorobots, or tethered surgical devices including catheters, endoscopes, and needles can be achieved by generating magnetic fields from outside the human body, using a magnetic navigation system. This thesis is divided in two parts. The first part discusses the prediction of generated magnetic fields, a fundamental task of remote magnetic navigation that is required for simulating, controlling, and localizing magnetically navigated devices. We first explore interpolation based methods, which create continuous representations of magnetic fields using pre-existing data. Several interpolation methods are compared based on their ability to accurately predict magnetic fields and magnetic field gradients, and how well they respect certain physical constraints obeyed by magnetic fields. Magnetic navigation systems using electromagnets that are large enough to perform magnetic navigation at human scales exhibit nonlinear magnetic saturation. We first propose a strategy that can correct for electromagnet saturation in existing linear models. Machine learning based methods are capable of modeling such complex nonlinear behavior with multiple inputs and outputs from data alone. We show an artificial neural network that achieved superior field prediction accuracy to both linear and corrected methods. This was followed by the application of a generative convolutional neural network that far outperformed all other methods. The second part of the thesis concerns the application of remote magnetic navigation for the control of tethered surgical devices in ophthalmology. Surgery on the retina is exceedingly challenging, involves movements and forces that are at the limits of human ability and perception, and for that reason has long been proposed as a candidate for the application of medical robotics. Differing from existing robots that use mechanical transfer of motion to navigate tools inside the cavity of the eye, this work presents flexible devices that are navigated using magnetic fields. Such devices combine fine position control, extreme miniaturization, and enhanced safety over existing rigid tools. We first describe a magnetically navigated laser probe that could be used for treating advanced forms of diabetic retinopathy, a rapidly growing and already leading cause of vision loss. By tracking the laser position in real-time using computer vision, the probe is navigated in closed-loop, and the procedure, which is repetitive, lengthy, and painful for patients, can be automated. There is active research in the development of new therapies for treating diseases that cause degeneration of the retina, particularly age-related macular degeneration, the leading cause… Advisors/Committee Members: Nelson, Bradley J., Becker, Matthias, Valdastri, Pietro.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Charreyron, S. (2020). Remote Magnetic Navigation and Applications in Ophthalmic Surgery. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/431062

Chicago Manual of Style (16^th Edition):

Charreyron, Samuel. “Remote Magnetic Navigation and Applications in Ophthalmic Surgery.” 2020. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/431062.

MLA Handbook (7^th Edition):

Charreyron, Samuel. “Remote Magnetic Navigation and Applications in Ophthalmic Surgery.” 2020. Web. 04 Mar 2021.

Vancouver:

Charreyron S. Remote Magnetic Navigation and Applications in Ophthalmic Surgery. [Internet] [Doctoral dissertation]. ETH Zürich; 2020. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/431062.

Council of Science Editors:

Charreyron S. Remote Magnetic Navigation and Applications in Ophthalmic Surgery. [Doctoral Dissertation]. ETH Zürich; 2020. Available from: http://hdl.handle.net/20.500.11850/431062

20. Dehghani, Ella S. Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts.

Degree: 2017, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/169422

► Abstract Bio-organic and bioinorganic layers featuring graded composition, structure and mechanical properties have been observed and studied in several biological systems, such as human cartilage,… (more)

▼ Abstract Bio-organic and bioinorganic layers featuring graded composition, structure and mechanical properties have been observed and studied in several biological systems, such as human cartilage, mammalian skin and the nacre of oyster shells. In order to mimic these natural structures and reproduce their properties, polymer chemists and materials scientists have made numerous efforts to synthesize polymer coatings with well-defined composition and tuneable physico-chemical characteristics. This thesis proposes several synthetic strategies to meet these challenging needs, especially focusing on the molecular modification of surface-grafted polymer assemblies. This general objective is accomplished i) by the controlled introduction of crosslinks through the formed films, and ii) by varying polymer parameters, such as grafting density and chain length, across the functionalized surface in a gradient fashion (Scheme 1). Schematic 1 Tuning through and across surface assemblies of polymer grafts (a) brush-hydrogel structure (b) gradient brush structure Surface-initiated controlled radical polymerization (SI-CRP) has been exploited to synthesize polymer brushes and their crosslinked analogues, i.e. brush-hydrogels, presenting well-defined composition and crosslinker concentration. In Chapter 3, the preparation of sub-100 nm-thick poly(hydroxyethyl methacrylate) (PHEMA) brush and brush-hydrogels by surface-initiated atom transfer polymerization (SI-ATRP), complementing the polymerization mixture with various amounts of di(ethylene glycol)- and tetra(ethylene glycol)-dimethacrylate crosslinkers (DEGDMA and TEGDMA, respectively) is reported. Having comprehensively characterized the surface composition and swelling properties of the formed polymer films by a combination of surface-sensitive techniques (such as quartz crystal microbalance, QCM-D, and variable angle spectroscopic ellipsometry, VASE) and X-ray photoelectron spectroscopy (XPS), I investigated the nanomechanical and nanotribological properties of the synthesized films by colloidal-probe atomic force microscopy (CP-AFM). These measurements highlighted how a precise variation of brush architecture can be translated into tunable stiffness and frictional characteristics. In addition, the composition of the PHEMA-based films, and in particular the concentration of EG units within the crosslinked layers, regulated the interaction of the functionalized surfaces with proteins of different types. In Chapter 4, the modification of PHEMA-based brushes and brush-hydrogels with ionizable, succinate groups (yielding PHEMA-SA films) is subsequently described. The swelling, nanomechanical and nanotribological properties of the modified films in response to a variation of pH of the medium were the focus of this study. Under acidic conditions, PHEMA-SA brushes and brush-hydrogels showed lower friction compared to the unmodified, PHEMA films in water. PHEMA-SA layers were found to be particularly compliant and, depending on the crosslinker concentration, either the… Advisors/Committee Members: Spencer Nicholas D., /, Benetti, Edmondo M., Schönherr, Holger.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dehghani, E. S. (2017). Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/169422

Chicago Manual of Style (16^th Edition):

Dehghani, Ella S. “Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts.” 2017. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/169422.

MLA Handbook (7^th Edition):

Dehghani, Ella S. “Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts.” 2017. Web. 04 Mar 2021.

Vancouver:

Dehghani ES. Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/169422.

Council of Science Editors:

Dehghani ES. Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/169422

ETH Zürich

21. Salmanpour, Amir Hosein. Displacement Capacity of Structural Masonry.

Degree: 2017, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/172566

► The development of the basis for the displacement-based seismic design of unreinforced masonry (URM) structures is the ultimate objective of the present research project, which… (more)

▼ The development of the basis for the displacement-based seismic design of unreinforced masonry (URM) structures is the ultimate objective of the present research project, which should be seen as the first step in an initiative to investigate the limits of the displacement capacity of contemporary URM walls. After a thorough survey and assessment of previous experimental and theoretical studies on the area of displacement capacity of URM walls, an experimental programme consisting of 10 static-cyclic shear tests on full-scale unreinforced clay and calcium-silicate masonry walls was carried out. The experimental programme aimed primarily at studying the effects of unit type, pre-compression level, aspect ratio, boundary conditions and size on the displacement capacity of contemporary URM walls. All the specimens (regardless of their failure mode) exhibited limited displacement capacity. The drift ratio capacity of the specimens that failed in shear was particularly small so that the mean value of the drift ratio capacity was 0.27% with a COV of 12%. However, the specimens that failed in flexure and in sliding-flexure combination exhibited larger drift ratio capacity, i.e. 0.32% and 0.62%, respectively. The test results showed that the drift ratio capacity decreases as the pre-compression level increases or as the aspect ratio decreases. Furthermore, they indicated a possible reduction in the drift ratio capacity in the case of an increase in the height (size effect). A direct relation was also found between the drift ratio capacity and the shear span, which is controlled by the boundary conditions. In addition, the calcium-silicate specimens showed slightly higher drift ratio capacity than the clay specimens. A comparison between the displacement capacity values obtained from the tests with those estimated according to current codes and guidelines showed that current codes of practice overestimate the displacement capacity of contemporary URM walls, so they could result in an unsafe design. Finally, based on the obtained test results, an empirical relationship for the force-displacement response of contemporary URM walls was proposed. In the theoretical part of the project, after a critical state-of-the-art review, a new mechanics-based model for the force-displacement response of URM walls failing in flexure was developed. The developed model gives a new insight into the seismic in-plane response of flexure-dominated URM walls. It combines the flexural and shear deformations with a rigid body rotation (a rocking type motion) resulted from the poor tensile strength of unreinforced masonry. A novel approach was developed to relate the rocking response to the strain state within the wall. The rocking response of URM walls has been widely disregarded so far; however, the developed model shows that its contribution to the seismic in-plane response of URM walls with flexural failure mode is substantial. Advisors/Committee Members: Schwartz, Joseph, Mojsilovic, Nebojša, Schultz, Arturo.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Salmanpour, A. H. (2017). Displacement Capacity of Structural Masonry. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/172566

Chicago Manual of Style (16^th Edition):

Salmanpour, Amir Hosein. “Displacement Capacity of Structural Masonry.” 2017. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/172566.

MLA Handbook (7^th Edition):

Salmanpour, Amir Hosein. “Displacement Capacity of Structural Masonry.” 2017. Web. 04 Mar 2021.

Vancouver:

Salmanpour AH. Displacement Capacity of Structural Masonry. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/172566.

Council of Science Editors:

Salmanpour AH. Displacement Capacity of Structural Masonry. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/172566

ETH Zürich

22. Burri, Michael. Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles.

Degree: 2017, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/169095

► With the ability to navigate freely in 3 D space, Micro Aerial Vehicles (MAVs) offer the possibility to reach places that are otherwise inaccessible to… (more)

▼ With the ability to navigate freely in 3 D space, Micro Aerial Vehicles (MAVs) offer the possibility to reach places that are otherwise inaccessible to humans. This is especially important for industrial inspection where the structures are large and need to be checked on a regular basis. However, doing this inspection remotely is difficult for a human pilot due to the fast dynamics of MAVs and how difficult it is to estimate distances to far away objects. In this thesis, we therefore wish to advance the capabilities of such systems through the development of a framework that can generate a 3 D map of the environment, and navigate between any points within this map without human intervention. Since MAVs are heavily restricted in terms of payload, the primary sensors used for navigation in this work are a stereo camera and an IMU. These sensors introduce interesting challenges and need to be considered in the design of each part of the visual navigation framework. The first contribution of this thesis is in state estimation and control. We showed that both parts can strongly benefit from a good model which provides valuable information about possible motions. Including the model in the state estimator combined with a pressure sensor renders the velocity and the two inclination angles observable. This is critical for control. Model Predictive Control (MPC) allows including the future trajectory and constraints given by the actuators and sensors in the optimization. The result is good trajectory tracking performance with smooth motions which in turn improves the vision based state estimation. For fully autonomous navigation state estimation needs to be extended with the capability to build a map of the environment and re-localize with respect to this map. In this thesis, we show how such a global mapping system can be used for visual navigation tasks on-board MAVs and how it can be extended for global planning. We carefully consider the implications of re-localization and possible failures in the mapping process. This consideration has enabled the development of a visual navigation framework that is well suited for industrial inspection. Many aspects of MAV navigation can benefit from an accurate model. Our last contribution is therein how to identify the model parameters. Based on Maximum Likelihood (ML) estimation we developed two approaches for parameter identification. The first provides the parameters that maximize the likelihood of all measurements and is used for off-line identification. In the second approach, we use a similar formulation but directly marginalize out old states and only keep the current mean and covariance. This allows on-line estimation of the parameters and the possibility for direct feedback in the controller. One of our key observations is that the quality of the parameter identification strongly depends on the motion. We validate these findings by developing a planner that generates informative trajectories that improve the identification. This leads to repeatable results and… Advisors/Committee Members: Siegwart, Roland, Alexis, Kostas.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Burri, M. (2017). Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/169095

Chicago Manual of Style (16^th Edition):

Burri, Michael. “Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles.” 2017. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/169095.

MLA Handbook (7^th Edition):

Burri, Michael. “Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles.” 2017. Web. 04 Mar 2021.

Vancouver:

Burri M. Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/169095.

Council of Science Editors:

Burri M. Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/169095

ETH Zürich

23. Schumacher, Christian. Computational Design of Structured Materials.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/341779

► Advances in manufacturing and processing techniques allow us to create objects with ever increasing complexity. This complexity can be used to create not only aesthetic… (more)

▼ Advances in manufacturing and processing techniques allow us to create objects with ever increasing complexity. This complexity can be used to create not only aesthetic forms, but also structured materials, whose geometries determine their deformation behavior. Systematic control over the elastic properties is possible with the right structures, but the relationship between structure and elastic properties is nontrivial. This highlights the need for new computational design approaches that can leverage the geometric complexity provided by advanced fabrication techniques, either by providing feedback about the deformation behavior throughout the design process, or by directly translating high-level functional targets into the appropriate material structure. This thesis introduces a novel set of techniques to characterize and create structured materials with various functional targets. We first introduce a data-driven microstructure synthesis approach. After creating a database of small-scale structures that show a clearly defined macroscopic deformation behavior when tiled, we use an interpolation method to create new structures from this database and design objects with spatially varying elastic properties. We then propose a design method to create surfaces with decorative cutouts that integrates aesthetics and stability into a single design process. We combine a discrete element texture approach with a topology optimization method to automatically optimizes the distribution of cutouts, creating a synergy of structure and function. Finally, we develop an approach to characterize the mechanical properties of tessellation-based networks of rods. We create a compact representation of the elastic behavior of such networks and explore the space of a specific type of tessellation, isohedral tilings, to show that we can create a broad range of mechanical behaviors from combinations of simple shapes. We present the resulting mechanical characterization using an intuitive visual representation that lends itself to an efficient exploration of the underlying space of structures. Advisors/Committee Members: Gross, Markus, Daraio, Chiara, Thomaszewski, Bernhard.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Schumacher, C. (2018). Computational Design of Structured Materials. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/341779

Chicago Manual of Style (16^th Edition):

Schumacher, Christian. “Computational Design of Structured Materials.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/341779.

MLA Handbook (7^th Edition):

Schumacher, Christian. “Computational Design of Structured Materials.” 2018. Web. 04 Mar 2021.

Vancouver:

Schumacher C. Computational Design of Structured Materials. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/341779.

Council of Science Editors:

Schumacher C. Computational Design of Structured Materials. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/341779

ETH Zürich

24. Hedinger, Raffael. Optimal Cold-Start Control Strategies for Gasoline Engines.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/359342

► In the first part of this thesis, generally valid rules for optimal control strategies during the catalyst heating phase at a high value of ignition… (more)

▼ In the first part of this thesis, generally valid rules for optimal control strategies during the catalyst heating phase at a high value of ignition retardation are identified experimentally. To this end, the effects of variations in control strategies are analyzed. Specifically, variations are analyzed in the center of combustion θ_{50}, in the air-to-fuel ratio λ and in maldistributions in both quantities among individual cylinders on the behavior of the engine in idling conditions after a cold start. This behavior includes the fuel consumption, the heat-up behavior of the three-way catalytic converter, and the cumulative tailpipe emission of HC, CO, and NO_x. A dedicated cylinder-individual, model-based, multi-variable controller is developed and used in experiments in order to isolate the effects of the individual control strategy variations as much as possible. An optimal control problem for a gasoline engine at a cold start is formulated which is used to interpret the experimental data obtained. The corresponding goal is to minimize the fuel consumption during an initial idling phase of a fixed duration while guaranteeing that the three-way catalytic converter reaches a sufficiently high final temperature and at the same time ensuring that the cumulative emissions stay below a given limit. The experimental data indicates that the engine should be operated with a maximum ignition retardation and at an air-to-fuel ratio of 5%-10% lean in order to reach any temperature inside the three-way catalytic converter as quickly as possible concurrently with minimum tailpipe emissions and at a minimum possible fuel consumption. In the second part of this thesis, trajectory tracking algorithms for gasoline engines are devised. Specifically, a simultaneous and precise reference tracking in engine speed, air-to-fuel ratio, and center of combustion is enabled. Such a tracking of multiple reference trajectories requires a coordinated control action for the air path, the fuel path, and the ignition timing actuators. Combining a dedicated feedforward and feedback controller structure and multivariable model-based norm-optimal parallel iterative learning control strategies, feedforward control trajectories are generated that enable a precise tracking of desired reference trajectories. Experimental results show the effectiveness of the proposed methodology. Advisors/Committee Members: Onder, Christopher, Eriksson, Lars, Fischer, Wolfgang, Noiray, Nicolas.

Subjects/Keywords: info:eu-repo/classification/ddc/620; Engineering & allied operations

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APA (6^th Edition):

Hedinger, R. (2019). Optimal Cold-Start Control Strategies for Gasoline Engines. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/359342

Chicago Manual of Style (16^th Edition):

Hedinger, Raffael. “Optimal Cold-Start Control Strategies for Gasoline Engines.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/359342.

MLA Handbook (7^th Edition):

Hedinger, Raffael. “Optimal Cold-Start Control Strategies for Gasoline Engines.” 2019. Web. 04 Mar 2021.

Vancouver:

Hedinger R. Optimal Cold-Start Control Strategies for Gasoline Engines. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/359342.

Council of Science Editors:

Hedinger R. Optimal Cold-Start Control Strategies for Gasoline Engines. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/359342

ETH Zürich

25. Pinto Teixeira, Lucas. Real-Time Monocular Dense Mapping and Localisation for Autonomous Aerial Navigation.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/381214

► On the quest of automating the navigation of small Unmanned Aerial Vehicles (UAVs), the research community has focused on developing perception capabilities able to run… (more)

▼ On the quest of automating the navigation of small Unmanned Aerial Vehicles (UAVs), the research community has focused on developing perception capabilities able to run onboard such platforms in real-time. Even though computer vision algorithms have been at the heart of recent advancements, their realistic employment onboard UAVs is still in its infancy. Inspired by challenges in autonomous aerial navigation, this thesis presents a collection of monocular algorithms developed for SLAM, as well as a novel fully autonomous system for aerial inspection. With real-time dense mapping posing an interesting problem onboard UAVs, this thesis begins by introducing three approaches with very distinctive trade-offs, using either visual-only or visual-inertial SLAM to estimate the current UAV pose and the 3D landmarks in the UAV's surroundings. The first mapping approach builds a 3D mesh of the local scene using the SLAM landmarks employing Delaunay Triangulation and a novel approach for geometric-based denoising and smoothing of this mesh. This algorithm is very efficient, consuming seven milliseconds in only one core of the onboard computer's CPU. Interpolated landmarks or a dense depth image of the current UAV's surroundings can be obtained by sampling the resulting mesh. Nevertheless, this mesh is only a rough representation of the underlying structure, working best in mostly planar scenes, while it is not capable of capturing details such small and thin structures (e.g. lampposts and tree leaves). For demonstrating the power of this mapping approach, this thesis also presents a pipeline to enable fully autonomous flights, which employ the mesh-based mapping algorithm and a novel aerial planner for inspection in unknown environments. This system is shown to achieve superior performance in large scale outdoor experiments. Inspired by the downsides of the meshing approach, the second mapping approach presented in this thesis is based on motion stereo, in essence, mimicking the visual output of a stereo camera by using two images from a moving monocular camera mounted on a UAV, informed with their correspondent SLAM camera poses. Employing superpixel-based extrapolation that consults the image intensities to guide the enhancement of the motion-stereo mapping, this real-time approach produces a denser and more accurate map of the environment than the mesh-based one, albeit at the expense of increased computational cost and slightly constrained camera motion to enable stereo-like scene views. Aiming to leverage the substantial body of literature in learning-based techniques for depth estimation, the last mapping approach presented here is based on a deep-learning approach. Similarly to the mesh-based approach, this method extrapolates the scene-depth of the field-of-view of the camera using the current SLAM landmarks and, similarly to the motion-stereo-based approach, it consults the colour values in the image to guide this extrapolation, this time eliminating the need for constraining the camera motion in any way.… Advisors/Committee Members: Chli, Margarita, id_orcid0000-0001-5611-7492, Siegwart, Roland, Civera, Javier.

Subjects/Keywords: Computer Vision; 3D reconstruction; info:eu-repo/classification/ddc/004; info:eu-repo/classification/ddc/620; Data processing, computer science; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Pinto Teixeira, L. (2019). Real-Time Monocular Dense Mapping and Localisation for Autonomous Aerial Navigation. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/381214

Chicago Manual of Style (16^th Edition):

Pinto Teixeira, Lucas. “Real-Time Monocular Dense Mapping and Localisation for Autonomous Aerial Navigation.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/381214.

MLA Handbook (7^th Edition):

Pinto Teixeira, Lucas. “Real-Time Monocular Dense Mapping and Localisation for Autonomous Aerial Navigation.” 2019. Web. 04 Mar 2021.

Vancouver:

Pinto Teixeira L. Real-Time Monocular Dense Mapping and Localisation for Autonomous Aerial Navigation. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/381214.

Council of Science Editors:

Pinto Teixeira L. Real-Time Monocular Dense Mapping and Localisation for Autonomous Aerial Navigation. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/381214

ETH Zürich

26. Hebestreit, Erik. Thermal Properties of Levitated Nanoparticles.

Degree: 2017, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/250832

►

Throughout the last century, scientists have been trying to understand the peculiar behavior of microscopic objects such as electrons, atoms, ions, and molecules. This behavior… (more)

▼

Throughout the last century, scientists have been trying to understand the peculiar behavior of microscopic objects such as electrons, atoms, ions, and molecules. This behavior is predicted by quantum mechanics. Especially surprising is that the laws of the quantum world contradict our expectations from classical mechanics. Therefore, it is a central question in quantum physics how the transition between these two regimes materializes. In this thesis, we address this fundamental question using a dielectric nanoparticle levitated in an optical focus in vacuum. This is a promising system for studying quantum mechanics with mesoscopic objects. We measure the internal temperature of this nanoparticle that fundamentally limits the lifetime of a quantum state of the center-of-mass motion. To do that, we study the dynamics of the particle's center-of-mass motion depending on the internal particle temperature. The second goal of this thesis is to perform a free-fall experiment with a levitated nanoparticle. This is a first step towards time-of-flight state tomography and quantum interferometry experiments with nanoparticles. By switching the optical trap off and back on, we achieve a repeatable free fall of the particle. We use this method to measure the initial energy of the particle motion before the free fall and demonstrate ultra-sensitive detection of static forces in the attonewton regime.

Während des letzten Jahrhunderts haben Wissenschaftler versucht das sonderbare Verhalten von mikroskopischen Objekten, wie Elektronen, Atomen, Ionen und Molekülen zu verstehen. Dieses Verhalten wird durch die Quantenmechanik beschrieben. Besonders überraschend ist, dass die Gesetze der Quantenwelt unseren Erwartungen der klassischen Mechanik widersprechen. Daher ist eine zentrale Frage in der Quantenphysik, wie der Übergang zwischen den zwei Regimen zustande kommt. In dieser Arbeit adressieren wir diese fundamentale Frage unter Verwendung eines dielektrischen Nanopartikels, welches in einem optischen Fokus im Vakuum schwebt. Dies ist ein vielversprechendes System, um Quantenmechanik mit mesoskopischen Objekten zu untersuchen. Wir messen die interne Temperatur dieses Nanopartikels, welche die Lebensdauer eines Quantenzustandes der Schwerpunktsbewegung fundamental limitiert. Dafür studieren wir die Dynamik der Schwerpunktsbewegung des Partikels in Abhängigkeit von der internen Partikeltemperatur. Das zweite Ziel der Arbeit ist es, ein Freifallexperiment mit einem schwebenden Nanopartikel durchzuführen. Dies ist ein erster Schritt hin zu Flugzeit Zustandstomografie und Quanteninterferenzexperimenten mit Nanopartikeln. Durch Aus- und wieder Einschalten der optischen Falle realisieren wir einen wiederholbaren Freifall des Partikels. Wir nutzen diese Methode um die Anfangsenergie der Partikelbewegung zu messen und demonstrieren die ultrasensitive Detektion von statischen Kräften im Attonewton-Bereich.

Advisors/Committee Members: Novotny, Lukas, Romero-Isart, Oriol, Home, Jonathan.

Subjects/Keywords: Optomechanics; Sensing; Nanoparticles; Optical tweezers; info:eu-repo/classification/ddc/530; info:eu-repo/classification/ddc/620; Physics; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hebestreit, E. (2017). Thermal Properties of Levitated Nanoparticles. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/250832

Chicago Manual of Style (16^th Edition):

Hebestreit, Erik. “Thermal Properties of Levitated Nanoparticles.” 2017. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/250832.

MLA Handbook (7^th Edition):

Hebestreit, Erik. “Thermal Properties of Levitated Nanoparticles.” 2017. Web. 04 Mar 2021.

Vancouver:

Hebestreit E. Thermal Properties of Levitated Nanoparticles. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/250832.

Council of Science Editors:

Hebestreit E. Thermal Properties of Levitated Nanoparticles. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/250832

ETH Zürich

27. Hack, Norman Peter. Mesh Mould: A Robotically Fabricated Structural Stay-in-Place Formwork System.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/263345

► Concrete is a highly versatile construction material, not only for the reason that it has excellent properties in terms of structural performance, building physics, availability… (more)

▼ Concrete is a highly versatile construction material, not only for the reason that it has excellent properties in terms of structural performance, building physics, availability and price, but also because it can be moulded into virtually any shape regardless of its geometric complexity. However, even though current digital design tools allow to effortlessly design and calculate structures, which are exploiting these properties, this potential remains all too often unrealized. This is due to the fact that geometrically complex concrete structures require expensive, one-of-a kind formwork, which can often not be reused or even recycled. Consequently, the current practice for producing non-standard curvilinear architecture in reinforced concrete is neither ecologically sustainable nor economically feasible for a broader range of architectural typologies. Additive fabrication processes, like 3D printing with concrete, on the other hand, currently struggle with the integration of structural reinforcement, limiting the technique to predominantly non-loadbearing applications. This research addresses both issues and proposes a robotic fabrication process, which unifies concrete formwork and structural reinforcement, and hence potentially reduces formwork waste and construction costs for non-standard reinforced concrete constructions. The development of a fully automated robotic fabrication process involved various research disciplines, including architecture, material science, mechanical engineering, robotics, civil engineering as well as control and vision engineering, and was conducted in three stages. A first conceptual stage investigated the reciprocal relationship of fresh concrete and the spatially extruded polymer meshes, and was followed by a second stage, investigating the translation of the material system from polymer to structurally superior steel meshes. In a final stage, the construction system was adapted and further developed to meet the challenges of 1:1 construction. The results were demonstrated in a final loadbearing structure, the Mesh Mould Wall of the DFAB HOUSE on NEST. In conclusion, the research presented in this thesis laid the foundation for developing this prototypical robotic fabrication system further into a commercial robotic construction system. Advisors/Committee Members: Kohler, Matthias, Gramazio, Fabio, Willmann, Jan S., Kilian, Axel.

Subjects/Keywords: Digital Fabrication; info:eu-repo/classification/ddc/720; info:eu-repo/classification/ddc/620; Architecture; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hack, N. P. (2018). Mesh Mould: A Robotically Fabricated Structural Stay-in-Place Formwork System. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/263345

Chicago Manual of Style (16^th Edition):

Hack, Norman Peter. “Mesh Mould: A Robotically Fabricated Structural Stay-in-Place Formwork System.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/263345.

MLA Handbook (7^th Edition):

Hack, Norman Peter. “Mesh Mould: A Robotically Fabricated Structural Stay-in-Place Formwork System.” 2018. Web. 04 Mar 2021.

Vancouver:

Hack NP. Mesh Mould: A Robotically Fabricated Structural Stay-in-Place Formwork System. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/263345.

Council of Science Editors:

Hack NP. Mesh Mould: A Robotically Fabricated Structural Stay-in-Place Formwork System. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/263345

ETH Zürich

28. Rentsch, Benedikt. Virtual Design and Adaptive Control of Metal Spinning Processes.

Degree: 2018, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/267320

► Metal spinning is classified as an incremental sheet metal forming process and as such features some unique advantages over conventional stamping operations. Their elevated number… (more)

▼ Metal spinning is classified as an incremental sheet metal forming process and as such features some unique advantages over conventional stamping operations. Their elevated number of degrees of freedom provides great flexibility on one hand, but is cumbersome to translate into standardized procedures on the other. Thus the design of the process layout is a challenging task, which is usually carried out manually by experienced personnel, based on a trial-and-error approach.FEM and meta-modelling are widely used state of the art methodologies for process analysis and optimization, but the application of these on metal spinning is very limited. Due to its highly dynamic and localised forming character, accurate modelling of the process relies on full scale 3D models. In combination with the comparably long process cycles, this mostly results in restrictive computational times, making classical virtual optimization infeasible.This works aims to discover systematic methodologies, which enable automated tool path design for metal spinning processes. In order to do this, the finite element method is employed and optimized in terms of computational time and resources. Based on the models, extensive insight on the deformation characteristics and the failure modes is provided. Subsequently, different concepts for automated tool path design are proposed. These are a closed loop control system, which is integrated into the models, enabling constrained and failure free tool path design, and a simplified model, which approximates the results of the adaptive control strategy, but is not bound to any computational effort.The functionality of the concepts for automated tool path design is verified on two different test geometries and materials. For proof of concept the results are validated with metal spinning tests, in which the computed paths have been applied via CNC machine, demonstrating that the developed methodologies indeed enable failure free production of components. A detailed comparison shows that these generally surpass the manual design in aspect of quality and cycle time. Advisors/Committee Members: Hora, Pavel, van den Boogaard, Ton.

Subjects/Keywords: Incremental sheet forming; Metal spinning; FEM Simulation; info:eu-repo/classification/ddc/620; info:eu-repo/classification/ddc/670; Engineering & allied operations; Manufacturing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rentsch, B. (2018). Virtual Design and Adaptive Control of Metal Spinning Processes. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/267320

Chicago Manual of Style (16^th Edition):

Rentsch, Benedikt. “Virtual Design and Adaptive Control of Metal Spinning Processes.” 2018. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/267320.

MLA Handbook (7^th Edition):

Rentsch, Benedikt. “Virtual Design and Adaptive Control of Metal Spinning Processes.” 2018. Web. 04 Mar 2021.

Vancouver:

Rentsch B. Virtual Design and Adaptive Control of Metal Spinning Processes. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/267320.

Council of Science Editors:

Rentsch B. Virtual Design and Adaptive Control of Metal Spinning Processes. [Doctoral Dissertation]. ETH Zürich; 2018. Available from: http://hdl.handle.net/20.500.11850/267320

ETH Zürich

29. Bützer, Tobias. Fully Wearable Actuated Hand Exoskeleton for Assistance in Daily Life and Therapy.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/358101

► Human hands combine unique dexterity and somatosensory abilities which are exceptional in living organisms and not reached in technology. How important hands are for our… (more)

▼ Human hands combine unique dexterity and somatosensory abilities which are exceptional in living organisms and not reached in technology. How important hands are for our daily living becomes evident when we temporarily or permanently lose the ability to use them and simple tasks like eating or grooming suddenly require assistance from a third person. Worldwide, far more than 50 million individuals suffer from upper limb impairment following neurological diseases or trauma such as stroke or spinal cord injury. Pain, spasticity, contractures, and weakness lead to disabilities ranging from poor finger individuation to complete paralysis of the hand and, consequently, to a major loss of independence and quality of life. In subjects with neuromotor hand impairment, it is well acknowledged that through robotics high dose and intensity in the training and a positive effect on the outcome of the rehabilitation therapy can be reached. However, many individuals remain with persistent hand impairment when they are discharged from the hospital after the typical treatments to restore the hand function have been applied. Whether or not there is potential for further recovery of the nervous system, the use of the hand and the therapy must be continued to at least maintain the residual hand function. The potential of wearable hand exoskeletons for assistance in daily living and continued home rehabilitation therapy has been recognized in research and industry, and numerous devices have been developed. However, the human hand is highly dexterous, powerful, and of leanest design. The emulation of its functions requires complex mechanical systems, and the trade-off between functionality and usability in daily life is challenging. Thus, no device has been presented that successfully combines the required capability for functional grasping tasks, full wearablility for use in daily living, and reliable, intuitive control. The aim of this work is to develop and evaluate a wearable robotic system fusing the concepts of assistance and therapy in the design of RELab tenoexo, a fully wearable actuated hand exoskeleton for assistance in daily life and with the potential for wearable all-day rehabilitation in the clinic or at home for subjects with neuromotor hand impairments. We identify the key design factors and requirements for such a device in continuous discussion with expert clinicians, interviews with users, and various usability studies. We realize that, in a first step, a fully wearable hand exoskeleton for assistance in daily living has to be designed, and only in a second step, through control based on physiological signals, this device can turn into a wearable system for assistance and rehabilitation. Based on the defined requirements and a previously presented hand exoskeleton, we suggest a detailed design concept for RELab tenoexo. We reduce the dexterity of the hand to few basic functions needed to perform the four most frequently used grasp types. With strict attention paid to ease of use, we present various… Advisors/Committee Members: Gassert, Roger, id_orcid0000-0002-6373-8518, Arata, Jumpei, van Hedel, Hubertus J..

Subjects/Keywords: info:eu-repo/classification/ddc/610; info:eu-repo/classification/ddc/620; Medical sciences, medicine; Engineering & allied operations

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bützer, T. (2019). Fully Wearable Actuated Hand Exoskeleton for Assistance in Daily Life and Therapy. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/358101

Chicago Manual of Style (16^th Edition):

Bützer, Tobias. “Fully Wearable Actuated Hand Exoskeleton for Assistance in Daily Life and Therapy.” 2019. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/358101.

MLA Handbook (7^th Edition):

Bützer, Tobias. “Fully Wearable Actuated Hand Exoskeleton for Assistance in Daily Life and Therapy.” 2019. Web. 04 Mar 2021.

Vancouver:

Bützer T. Fully Wearable Actuated Hand Exoskeleton for Assistance in Daily Life and Therapy. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/358101.

Council of Science Editors:

Bützer T. Fully Wearable Actuated Hand Exoskeleton for Assistance in Daily Life and Therapy. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/358101

ETH Zürich

30. Sigrist, Lukas. Design and Instrumentation of Environment-Powered Systems.

Degree: 2020, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/403889

► Energy Harvesting presents a key technology to sustainably supply the billions of devices in the emerging Internet of Things (IoT). Converting physical signals such as… (more)

▼ Energy Harvesting presents a key technology to sustainably supply the billions of devices in the emerging Internet of Things (IoT). Converting physical signals such as radiation, temperature, vibration, etc. into electrical energy promises virtually unlimited energy to supply cyber-physical systems (CPSs) in a long-term and scalable manner. However, with an energy supply depending on a spatially and temporally variable environment significant non-determinism is introduced into the system. In this thesis we explore the potential and limitations of supplying cyber-physical systems (CPSs) from environmental energy using only minimal energy buffering. We introduce novel design methodologies to supply applications reliably and efficiently, explore the energy yield of thermoelectric harvesting, and optimize the utility of data transmissions in infrastructure-less monitoring. Furthermore, we introduce a testbed and measurement support to assist designers in design aspects arising in energy harvesting systems. Specifically, we make the following contributions: - We introduce a novel measurement tool that combines high accuracy and portability. Enabling joint in-situ observations of the ambient, multiple energy flows, and application states, it provides critical insights during the design and verification of energy harvesting systems. - We present a testbed for the emulation of radiation and temperature environments. In combination with a programmable, time- and event-triggered current sink, it enables fast and repeatable exploration, dimensioning and validation of energy harvesting system design aspects. - We introduce the first model for thermoelectric energy harvesting at the ground-to-air boundary that incorporates all components from the physical signal to the application. In combination with a newly proposed rectifier circuit, an optimized harvesting system is implemented. Extensive real-world evaluation attests the accuracy of the model and demonstrates unprecedented output power in the given harvesting scenario. - We propose a novel energy management principle that decouples the energy harvesting and electrical load using a minimal energy buffer to allow each end to operate at is optimal operating point. An energy management unit (EMU) implementing this principle is designed and extensively evaluated. Efficient and reliable operation is demonstrated, even when the input power is significantly lower than the application requirements and exhibiting high variability. - We study the utility of data transmitted in an infrastructure-less communication scenario supplied by energy harvesting. Using a model-based optimization approach, we derive a new data transmission scheme for long-term batteryless monitoring applications. Evaluation using a batteryless sensor nodes demonstrates accurate abstraction of the scenario using our model and significant gain in utility at minimal run-time overhead. The methods and solutions presented are implemented and extensively evaluated under lab and real-world conditions. From these, we… Advisors/Committee Members: Thiele, Lothar, Mottola, Luca, Beutel, Jan, id_orcid0000-0003-0879-2455.

Subjects/Keywords: Energy harvesting; Transient computing; info:eu-repo/classification/ddc/620; info:eu-repo/classification/ddc/621.3; Engineering & allied operations; Electric engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sigrist, L. (2020). Design and Instrumentation of Environment-Powered Systems. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/403889

Chicago Manual of Style (16^th Edition):

Sigrist, Lukas. “Design and Instrumentation of Environment-Powered Systems.” 2020. Doctoral Dissertation, ETH Zürich. Accessed March 04, 2021. http://hdl.handle.net/20.500.11850/403889.

MLA Handbook (7^th Edition):

Sigrist, Lukas. “Design and Instrumentation of Environment-Powered Systems.” 2020. Web. 04 Mar 2021.

Vancouver:

Sigrist L. Design and Instrumentation of Environment-Powered Systems. [Internet] [Doctoral dissertation]. ETH Zürich; 2020. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/20.500.11850/403889.

Council of Science Editors:

Sigrist L. Design and Instrumentation of Environment-Powered Systems. [Doctoral Dissertation]. ETH Zürich; 2020. Available from: http://hdl.handle.net/20.500.11850/403889

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