subject:(Engineering allied operations)

1. Riaz, Muhammad. Novel miniature microwave quasi-elliptical function bandpass filters with wideband harmonic suppression.

Degree: PhD, 2017, London Metropolitan University

URL: http://repository.londonmet.ac.uk/1262/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724545

► Filters are integral components in all wireless communication systems, and their function is to permit predefined band of frequencies into the system and reject all… (more)

▼ Filters are integral components in all wireless communication systems, and their function is to permit predefined band of frequencies into the system and reject all other signals. The ever-growing demand in the use of the radio frequency (RF) spectrum for new applications has resulted in the need for high performance microwave filters with strict requirements on both inband and out-of-band characteristics. High selectivity, high rejection, low loss and extremely wide spurious-free performance are required for both transmitter and receiver channels. In addition, these devices need to be highly compact, easy to integrate within transceivers and should be amenable to low cost manufacturing. High selectivity is essential to enable the guard band between adjacent channels to be reduced thus improving the efficiency of the RF spectrum and hence increasing the capacity of the system. A low insertion-loss, high return-loss and small group-delay in the passband are necessary to minimize signal degradation. A wide stopband is necessary to suppress spurious passbands outside the filter’s bandwidth that may allow spurious emissions from modulation process (harmonic, parasitic, intermodulation and frequency conversion products) and interfere with other systems. The EMC Directive 89/336/EEC mandates that all electronic equipment must comply with the applicable EN specification for EMI. This thesis presents the research work that has resulted in the development of innovative and compact microstrip bandpass filters that fulfil the above stringent requirements for wireless communication systems. In fact, the proposed highly compact planar microstrip filters provide an alternative solution for existing and next generation of wireless communications systems. In particular, the proposed filters exhibit a low-loss and quasi-elliptic function response that is normally only possible with filter designs using waveguides and high temperature superconductors. The selectivity of the filters has been improved by inserting a pair of transmission zeros between the passband edges, and implementing notched rejection bands in the filter’s frequency response to widen its stopband performance. The filter structures have been analysed theoretically and modelled by using Keysight Technologies’ Advanced Design System (ADS™) and Momentum® software. The dissertation is essentially composed of four main sections. In the first section, several compact and quasi-elliptic function bandpass filter structures are proposed and theoretically analysed. Selectivity and stopband performance of these filters is enhanced by loading the input and output feed-lines with inductive stubs that introduce transmission zeros at specified frequencies in the filter’s frequency response. This technique is shown to provide a sharp 3-dB roll-off and steep selectivity skirt with high out-of-band rejection over a wide frequency span. In addition, the 3-dB fractional bandwidth of the filters is shown to be controllable by manipulating the filter’s geometric parameters. Traditional…

Subjects/Keywords: 620; 620 Engineering & allied operations

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APA (6^th Edition):

Riaz, M. (2017). Novel miniature microwave quasi-elliptical function bandpass filters with wideband harmonic suppression. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/1262/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724545

Chicago Manual of Style (16^th Edition):

Riaz, Muhammad. “Novel miniature microwave quasi-elliptical function bandpass filters with wideband harmonic suppression.” 2017. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/1262/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724545.

MLA Handbook (7^th Edition):

Riaz, Muhammad. “Novel miniature microwave quasi-elliptical function bandpass filters with wideband harmonic suppression.” 2017. Web. 24 Feb 2021.

Vancouver:

Riaz M. Novel miniature microwave quasi-elliptical function bandpass filters with wideband harmonic suppression. [Internet] [Doctoral dissertation]. London Metropolitan University; 2017. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/1262/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724545.

Council of Science Editors:

Riaz M. Novel miniature microwave quasi-elliptical function bandpass filters with wideband harmonic suppression. [Doctoral Dissertation]. London Metropolitan University; 2017. Available from: http://repository.londonmet.ac.uk/1262/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724545

2. Cullinan, Michael. Equation defined device modelling of floating gate M.O.S.F.E.Ts.

Degree: PhD, 2015, London Metropolitan University

URL: http://repository.londonmet.ac.uk/960/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681356

► This research work covers the development of a novel compact model for a Floating Gate nMOSFET that will be added to the QUCS library. QUCS… (more)

▼ This research work covers the development of a novel compact model for a Floating Gate nMOSFET that will be added to the QUCS library. QUCS (Quite Universal Circuit Simulator) is a GPL simulation software package that was created in 2006 and is continuing to develop and evolve, and there is already a substantial library of components, devices and circuits. Fundamentally, a floating gate device is an analogue device, even though modern technology uses it mainly as a non-volatile memory element there are numerous uses for it as an analogue device. A study has been carried out with regards to the principles of the physical phenomenon of charge transfer through silicon dioxide to a floating gate. The study has concentrated on the physical properties of the fabricated device and the principles of charge transfer through an oxide layer by Fowler–Nordheim principles. The EKV2.6 MOSFET was used as the fundamental device for the model that has been adapted by the addition of the floating gate. An equivalent circuit of an FGMOSFET was developed and analysed theoretically. This was then formulated into the QUCs environment and created as a compact model. Simulations were carried out and the results analysed to compare with the theoretical expectations and previous research works. It is well documented that the creation of equivalent circuits for floating gate devices is complicated by the fact that the floating gate is isolated as a node and as such cannot be directly analysed by simulators. For the equivalent circuit created, circuit analysis was achieved by the introduction of high value resistances connected in parallel with the capacitive elements that are representative of the incursion of the floating gate that is intrinsic to a floating gate device. The resistance elements were of such value that the time constants were of the order of 10000s and did not interfere with the simulation. The equations from the analysis were formulated and the anticipated responses were shown. The analytical equations developed were then used within the QUCS environment with explicit use of EDDs(Equation Defined Devices) to create a novel model of a FGMOSFET. Simulations of the model created were carried out with a range of voltage pulses being applied to the tunnelling terminal to affect a charge transfer to the floating gate by means of Fowler-Nordheim principles. The changes of the charge stored on the floating gate were clearly shown by the measured anticipated associated shift in the Threshold voltage. Simulated results have been compared with previous research and development work and the new model is considered effective. Also because of the ability of the QUCS software to allow the variation of the multiplicity of the parameters associated with the fabrication process, it is considered to be adaptable to a range of modern floating gate device structures and materials.

Subjects/Keywords: 621.3815; 620 Engineering & allied operations

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APA (6^th Edition):

Cullinan, M. (2015). Equation defined device modelling of floating gate M.O.S.F.E.Ts. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/960/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681356

Chicago Manual of Style (16^th Edition):

Cullinan, Michael. “Equation defined device modelling of floating gate M.O.S.F.E.Ts.” 2015. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/960/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681356.

MLA Handbook (7^th Edition):

Cullinan, Michael. “Equation defined device modelling of floating gate M.O.S.F.E.Ts.” 2015. Web. 24 Feb 2021.

Vancouver:

Cullinan M. Equation defined device modelling of floating gate M.O.S.F.E.Ts. [Internet] [Doctoral dissertation]. London Metropolitan University; 2015. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/960/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681356.

Council of Science Editors:

Cullinan M. Equation defined device modelling of floating gate M.O.S.F.E.Ts. [Doctoral Dissertation]. London Metropolitan University; 2015. Available from: http://repository.londonmet.ac.uk/960/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681356

ETH Zürich

3. 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 February 24, 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. 24 Feb 2021.

Vancouver:

Fontana FF. Additive Manufacturing: Tools and Methods Supporting Early Adopters in a Focused Implementation. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

4. 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 February 24, 2021. http://hdl.handle.net/20.500.11850/372432.

MLA Handbook (7^th Edition):

Chen, Mingyang. “Sorption-Induced Deformation of Nanoporous Materials.” 2019. Web. 24 Feb 2021.

Vancouver:

Chen M. Sorption-Induced Deformation of Nanoporous Materials. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

5. 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 February 24, 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. 24 Feb 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 Feb 24]. 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

6. 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 February 24, 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. 24 Feb 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 Feb 24]. 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

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

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 February 24, 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. 24 Feb 2021.

Vancouver:

Hutter R. Model-Based Analysis and Control of a Diesel-Ignited Gas Engine. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

8. 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 (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 February 24, 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. 24 Feb 2021.

Vancouver:

Petrović M. Use of Soft Layers for Seismic Response Modification of Structural Masonry Walls. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Feb 24]. 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

9. 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 February 24, 2021. http://hdl.handle.net/20.500.11850/382356.

MLA Handbook (7^th Edition):

Rigger, Eugen. “Task Definition for Design Automation.” 2019. Web. 24 Feb 2021.

Vancouver:

Rigger E. Task Definition for Design Automation. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

10. 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 February 24, 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. 24 Feb 2021.

Vancouver:

Lataniotis C. Data-driven uncertainty quantification for high-dimensional engineering problems. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

11. 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 (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 February 24, 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. 24 Feb 2021.

Vancouver:

Charreyron S. Remote Magnetic Navigation and Applications in Ophthalmic Surgery. [Internet] [Doctoral dissertation]. ETH Zürich; 2020. [cited 2021 Feb 24]. 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

12. 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

10 more images…

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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 February 24, 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. 24 Feb 2021.

Vancouver:

Dehghani ES. Molecular Tuning Through and Across Surface Assemblies of Polymer Grafts. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Feb 24]. 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

13. 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 February 24, 2021. http://hdl.handle.net/20.500.11850/172566.

MLA Handbook (7^th Edition):

Salmanpour, Amir Hosein. “Displacement Capacity of Structural Masonry.” 2017. Web. 24 Feb 2021.

Vancouver:

Salmanpour AH. Displacement Capacity of Structural Masonry. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Feb 24]. 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

14. Patel, Prakash Shashikant. Diffusion problems and degradation of bearing overlays.

Degree: PhD, 1989, London Metropolitan University

URL: http://repository.londonmet.ac.uk/3192/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293788

The corrosion and degradation of Pb-Sn bearing overlays Is a bilateral process . During service, the lubricant becomes corrosive due to the breakdown of inhibitors with subsequent oxidation occurring at operating temperatures (120-170[degrees]). ...

Subjects/Keywords: 620.11223; 620 Engineering & allied operations

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APA (6^th Edition):

Patel, P. S. (1989). Diffusion problems and degradation of bearing overlays. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/3192/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293788

Chicago Manual of Style (16^th Edition):

Patel, Prakash Shashikant. “Diffusion problems and degradation of bearing overlays.” 1989. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/3192/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293788.

MLA Handbook (7^th Edition):

Patel, Prakash Shashikant. “Diffusion problems and degradation of bearing overlays.” 1989. Web. 24 Feb 2021.

Vancouver:

Patel PS. Diffusion problems and degradation of bearing overlays. [Internet] [Doctoral dissertation]. London Metropolitan University; 1989. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/3192/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293788.

Council of Science Editors:

Patel PS. Diffusion problems and degradation of bearing overlays. [Doctoral Dissertation]. London Metropolitan University; 1989. Available from: http://repository.londonmet.ac.uk/3192/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293788

15. Wood, David John. Complex boundary integral techniques for turbomachinery blading.

Degree: PhD, 1981, London Metropolitan University

URL: http://repository.londonmet.ac.uk/3154/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291927

► Integral equation techniques are used to solve interior and exterior (including cascade) Neumann problems. The equations are in terms of the boundary values of the… (more)

Subjects/Keywords: 621; 620 Engineering & allied operations

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APA (6^th Edition):

Wood, D. J. (1981). Complex boundary integral techniques for turbomachinery blading. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/3154/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291927

Chicago Manual of Style (16^th Edition):

Wood, David John. “Complex boundary integral techniques for turbomachinery blading.” 1981. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/3154/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291927.

MLA Handbook (7^th Edition):

Wood, David John. “Complex boundary integral techniques for turbomachinery blading.” 1981. Web. 24 Feb 2021.

Vancouver:

Wood DJ. Complex boundary integral techniques for turbomachinery blading. [Internet] [Doctoral dissertation]. London Metropolitan University; 1981. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/3154/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291927.

Council of Science Editors:

Wood DJ. Complex boundary integral techniques for turbomachinery blading. [Doctoral Dissertation]. London Metropolitan University; 1981. Available from: http://repository.londonmet.ac.uk/3154/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291927

16. Bougas, Vassilis. The development of a crystal modulator using a multipath reflection technique.

Degree: PhD, 1993, London Metropolitan University

URL: http://repository.londonmet.ac.uk/3301/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358141

► An AOP lumped crystal transverse modulator has been developed, based upon a novel crystal cut, which operates at much lower driving voltages than presently available… (more)

Subjects/Keywords: 620; 620 Engineering & allied operations

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APA (6^th Edition):

Bougas, V. (1993). The development of a crystal modulator using a multipath reflection technique. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/3301/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358141

Chicago Manual of Style (16^th Edition):

Bougas, Vassilis. “The development of a crystal modulator using a multipath reflection technique.” 1993. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/3301/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358141.

MLA Handbook (7^th Edition):

Bougas, Vassilis. “The development of a crystal modulator using a multipath reflection technique.” 1993. Web. 24 Feb 2021.

Vancouver:

Bougas V. The development of a crystal modulator using a multipath reflection technique. [Internet] [Doctoral dissertation]. London Metropolitan University; 1993. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/3301/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358141.

Council of Science Editors:

Bougas V. The development of a crystal modulator using a multipath reflection technique. [Doctoral Dissertation]. London Metropolitan University; 1993. Available from: http://repository.londonmet.ac.uk/3301/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358141

17. Ray, G. P. Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment.

Degree: PhD, 1983, London Metropolitan University

URL: http://repository.londonmet.ac.uk/3426/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344180

► Some aspects of the corrosion fatigue crack initiation in EN1 type mild steel have been studied. Results of the electrochemical investigations show that the application… (more)

Subjects/Keywords: 669; 620 Engineering & allied operations

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APA (6^th Edition):

Ray, G. P. (1983). Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/3426/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344180

Chicago Manual of Style (16^th Edition):

Ray, G P. “Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment.” 1983. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/3426/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344180.

MLA Handbook (7^th Edition):

Ray, G P. “Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment.” 1983. Web. 24 Feb 2021.

Vancouver:

Ray GP. Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment. [Internet] [Doctoral dissertation]. London Metropolitan University; 1983. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/3426/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344180.

Council of Science Editors:

Ray GP. Some aspects of crack initiation in mild steel subjected to fatigue stressing in a corrosive environment. [Doctoral Dissertation]. London Metropolitan University; 1983. Available from: http://repository.londonmet.ac.uk/3426/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344180

18. Konyn, Mark. Collision avoidance at sea and on a marine radar simulator using automatic encounter detection techniques.

Degree: PhD, 1986, London Metropolitan University

URL: http://repository.londonmet.ac.uk/3212/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375091

► Considerable interest has recently been shown in the field of marine traffic engineering. Real life data sources made available for maritime studies are often expensive… (more)

Subjects/Keywords: 629.045; 620 Engineering & allied operations

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APA (6^th Edition):

Konyn, M. (1986). Collision avoidance at sea and on a marine radar simulator using automatic encounter detection techniques. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/3212/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375091

Chicago Manual of Style (16^th Edition):

Konyn, Mark. “Collision avoidance at sea and on a marine radar simulator using automatic encounter detection techniques.” 1986. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/3212/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375091.

MLA Handbook (7^th Edition):

Konyn, Mark. “Collision avoidance at sea and on a marine radar simulator using automatic encounter detection techniques.” 1986. Web. 24 Feb 2021.

Vancouver:

Konyn M. Collision avoidance at sea and on a marine radar simulator using automatic encounter detection techniques. [Internet] [Doctoral dissertation]. London Metropolitan University; 1986. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/3212/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375091.

Council of Science Editors:

Konyn M. Collision avoidance at sea and on a marine radar simulator using automatic encounter detection techniques. [Doctoral Dissertation]. London Metropolitan University; 1986. Available from: http://repository.londonmet.ac.uk/3212/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375091

19. Strange, J. L. An investigation of navigational decisions.

Degree: PhD, 1984, London Metropolitan University

URL: http://repository.londonmet.ac.uk/3370/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.349668

► This work is concerned with an examination of how the Merchant Navy Navigators use the information provided by the different aids. It is divided into… (more)

Subjects/Keywords: 629.045; 620 Engineering & allied operations

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

APA (6^th Edition):

Strange, J. L. (1984). An investigation of navigational decisions. (Doctoral Dissertation). London Metropolitan University. Retrieved from http://repository.londonmet.ac.uk/3370/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.349668

Chicago Manual of Style (16^th Edition):

Strange, J L. “An investigation of navigational decisions.” 1984. Doctoral Dissertation, London Metropolitan University. Accessed February 24, 2021. http://repository.londonmet.ac.uk/3370/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.349668.

MLA Handbook (7^th Edition):

Strange, J L. “An investigation of navigational decisions.” 1984. Web. 24 Feb 2021.

Vancouver:

Strange JL. An investigation of navigational decisions. [Internet] [Doctoral dissertation]. London Metropolitan University; 1984. [cited 2021 Feb 24]. Available from: http://repository.londonmet.ac.uk/3370/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.349668.

Council of Science Editors:

Strange JL. An investigation of navigational decisions. [Doctoral Dissertation]. London Metropolitan University; 1984. Available from: http://repository.londonmet.ac.uk/3370/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.349668

ETH Zürich

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

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 February 24, 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. 24 Feb 2021.

Vancouver:

Burri M. Vision-Based Navigation and Parameter Identification for Unmanned Aerial Vehicles. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2021 Feb 24]. 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

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

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 February 24, 2021. http://hdl.handle.net/20.500.11850/341779.

MLA Handbook (7^th Edition):

Schumacher, Christian. “Computational Design of Structured Materials.” 2018. Web. 24 Feb 2021.

Vancouver:

Schumacher C. Computational Design of Structured Materials. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Feb 24]. 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

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

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 February 24, 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. 24 Feb 2021.

Vancouver:

Hedinger R. Optimal Cold-Start Control Strategies for Gasoline Engines. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

23. 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 February 24, 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. 24 Feb 2021.

Vancouver:

Bürki M. Efficient Visual Localization for Ground Vehicles in Outdoor Environments. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

24. 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 February 24, 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. 24 Feb 2021.

Vancouver:

Bösch PM. Autonomous Vehicles - The next Revolution in Mobility. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Feb 24]. 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

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

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 February 24, 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. 24 Feb 2021.

Vancouver:

Li B. Assessment of Cascading Failures Risks and Development of Mitigation Strategies. [Internet] [Doctoral dissertation]. ETH Zürich; 2018. [cited 2021 Feb 24]. 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

ETH Zürich

26. Roh, Philip. Methoden zur datengetriebenen Lokalisierung des Verbesserungspotentials in Produktionsabläufen.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/370352

► The aim of this scientific treatise is to support manufacturing companies in increas-ing the productivity of their production processes, one of their classic challenges. The… (more)

▼ The aim of this scientific treatise is to support manufacturing companies in increas-ing the productivity of their production processes, one of their classic challenges. The methods presented in this thesis are developed to localize the potential for im-provement in production processes. On this basis, appropriate measures can be tak-en to improve the production process, for example through targeted financial in-vestments. The work presented is at the cutting edge of current developments: On the one hand, today's production is a complex and dynamic system that is comprehensively influenced by its environment. Such a production contains production processes, which are characterized by the demand for an increased number of product variants to be produced at the same time in combination with strongly fluctuating demand loads. This increases both, the dependencies and the fluctuations, within the production processes, which ultimately leads to increased dynamics. On the other hand, the changes that accompany the digitization and interconnection of production processes show new possibilities to counteract this complexity with the help of data-based methods and algorithms. By digitizing the relevant production data, it is possible to interconnect production processes internally and thus capture the production process as a whole. This enables the localization of improvement potentials in dynamic pro-duction processes. Three data-driven methods are developed to localize the potential for improvement in production processes that master the increased complexity and utilize the potential of the production data. The first method localizes the potential for productivity improvement by detecting bottlenecks with a data-driven algorithm. For the first time, productvariant-specific and time-variant bottlenecks can be localized. This is of particular importance for modern production lines, where a large number of product variants are produced simultaneously and in a changing mix. In addition, the method has the advantage over existing procedures that no model assumptions and no simulation models are necessary. The presented method for the localization of bottlenecks answers the question "where" the problem occurs in a production process. However, it makes no statement about "what" the problem is. The second method - the information stream mapping - localizes the improvement potential in information streams and thus provides the methodical tool for visualization, analysis and evaluation of information streams. Similar to value stream map-ping, an information stream map is created, which is then evaluated using five newly developed parameters for information streams (level of automation, media disruption rate, real-time capability, centrality index and first pass yield for information). Based on this evaluation, information streams in production processes can be ana-lysed and optimized. The method opens the possibility of increasing productivity in an area of production to which little attention has been paid so far. Information… Advisors/Committee Members: Kunz, Andreas, id_orcid0000-0002-6495-4327, Netland, Torbjørn H., Wegener, Konrad.

Subjects/Keywords: PRODUCTION MANAGEMENT (PRODUCTION); Information Stream Mapping; Bottleneck Detection; info:eu-repo/classification/ddc/620; info:eu-repo/classification/ddc/620; Engineering & allied operations; Engineering & allied operations

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

APA (6^th Edition):

Roh, P. (2019). Methoden zur datengetriebenen Lokalisierung des Verbesserungspotentials in Produktionsabläufen. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/370352

Chicago Manual of Style (16^th Edition):

Roh, Philip. “Methoden zur datengetriebenen Lokalisierung des Verbesserungspotentials in Produktionsabläufen.” 2019. Doctoral Dissertation, ETH Zürich. Accessed February 24, 2021. http://hdl.handle.net/20.500.11850/370352.

MLA Handbook (7^th Edition):

Roh, Philip. “Methoden zur datengetriebenen Lokalisierung des Verbesserungspotentials in Produktionsabläufen.” 2019. Web. 24 Feb 2021.

Vancouver:

Roh P. Methoden zur datengetriebenen Lokalisierung des Verbesserungspotentials in Produktionsabläufen. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. Available from: http://hdl.handle.net/20.500.11850/370352.

Council of Science Editors:

Roh P. Methoden zur datengetriebenen Lokalisierung des Verbesserungspotentials in Produktionsabläufen. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/370352

27. 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 February 24, 2021. http://hdl.handle.net/20.500.11850/380415.

MLA Handbook (7^th Edition):

Landig, Andreas. “Hybrid Circuit QED with Spin Qubits.” 2019. Web. 24 Feb 2021.

Vancouver:

Landig A. Hybrid Circuit QED with Spin Qubits. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. 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

28. Danzi, Mario. Consolidation Problems in Composite Processes.

Degree: 2020, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/431361

► The use of composite materials in structural applications is limited by the high costs associated with the production of the components. The research of cost-effective… (more)

▼ The use of composite materials in structural applications is limited by the high costs associated with the production of the components. The research of cost-effective solutions leads to the exploration of innovative manufacturing approaches. One of those is the combined prepreg / liquid composite molding (LCM) process. This manufacturing technique consists in the combination of prepreg materials with dry fabrics, subsequently impregnated by the injection of a liquid resin. The main ad-vantage of the combined process is the possibility to exploit the characteristics of the two manufacturing approaches in different regions of the same component. This shall enable the manufacturing of structures with a high level of integration and increase the effectiveness of the production. New challenges arise when combining different manufacturing techniques. A characteristic phenomenon of the combined prepreg/LCM process is the bleeding of the prepreg resin into the dry fabric. Such consolidation problem has a relevant influence on the properties of the cured laminate and needs to be understood to guarantee a good reliability of the process. The main objective of this thesis is the description and study of the mechanisms driving the consolidation of a stack of reinforcement plies. The first part of the work aims at establishing the manufacturing procedures for the combined out-of-autoclave (OOA) prepreg / vacuum assisted resin transfer molding (VARTM) process. Following an experimental approach, the main characteristics of the process are described and the influence of the process parameters on the composite quality is assessed. The derived procedures are then validated with the production of a representative aerospace demonstrator component. In the second part of the thesis, the material properties sup-porting the modeling of the consolidation process, i.e. fiber bed through-thickness compaction and permeability, are investigated. A new approach for the characterization of the quasi-static and dynamic (time-dependent) compaction response of fiber beds is proposed and validated for different conditions. Furthermore, an experimental setup and procedure for the derivation of the “true” fiber bed through-thickness saturated permeability is established. The characterization method is validated exploiting a numerical model to assess the deformation the fiber bed sample during the experiment. Finally, the derived material properties are implemented in coupled finite element models describing the consolidation of reinforcement plies and the resin flow in composite manufacturing processes. The simulation of a saturated consolidation is validated against experimental data measured in a dedicated setup. The observations made in this thesis contribute to a better understanding of consolidation phenomena in composite manufacturing processes. The insight shall support the definition of manufacturing and design guidelines, aiming at increasing the reliability and robustness of the production of composite components. Advisors/Committee Members: Ermanni, Paolo A., Advani, Suresh G., Klunker, Florian.

Subjects/Keywords: Composite; Consolidation model; Permeability; 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):

Danzi, M. (2020). Consolidation Problems in Composite Processes. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/431361

Chicago Manual of Style (16^th Edition):

Danzi, Mario. “Consolidation Problems in Composite Processes.” 2020. Doctoral Dissertation, ETH Zürich. Accessed February 24, 2021. http://hdl.handle.net/20.500.11850/431361.

MLA Handbook (7^th Edition):

Danzi, Mario. “Consolidation Problems in Composite Processes.” 2020. Web. 24 Feb 2021.

Vancouver:

Danzi M. Consolidation Problems in Composite Processes. [Internet] [Doctoral dissertation]. ETH Zürich; 2020. [cited 2021 Feb 24]. Available from: http://hdl.handle.net/20.500.11850/431361.

Council of Science Editors:

Danzi M. Consolidation Problems in Composite Processes. [Doctoral Dissertation]. ETH Zürich; 2020. Available from: http://hdl.handle.net/20.500.11850/431361

ETH Zürich

29. Maamari, Nadim. Smart Active Aerostatic Bearing.

Degree: 2019, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/431500

► Bearings and guideways are critical components in precision positioning machines. Among diverse types of bearing technologies, passive aerostatic bearings offer excellent precision to cost ratio,… (more)

▼ Bearings and guideways are critical components in precision positioning machines. Among diverse types of bearing technologies, passive aerostatic bearings offer excellent precision to cost ratio, yet have limited performance due to the inherent compromise between stiffness and damping, hindering the performance of the machine. Active bearing solutions based on either magnetic or aerostatic levitation rely heavily on the positioning feedback measurements needed for disturbance rejection, and are sensitive to electronic noises, which requires a compromise between system bandwidth and positioning stability. This thesis deals with the development of a disruptive technology involving a smart active aerostatic bearing. The concept is based on a centrally fed orifice compensation air bearing that features a compliance in the bearing back plate rendering it deformable to the air pressure distribution. The novel design based on integrated leaf springs ensures a linear gap deformation along the radial direction, represented by a conicity angle. The featured variation in the conicity angle is optimized to mechanically amplify the response of the pad to external loading, resulting in ultra-high passive stiffness. To ensure positioning capabilities, a Lorentz based actuator having the magnets mounted on the outer radius of the pad’s back plate and a coil attached to the center, induces a torque altering the conicity angle, resulting in servo actuation and positioning functionality. The linear gap deformation overcomes the dilemma’s between high passive stiffness and servo compliance. A novel nonlinear numerical model encapsulating the interaction between, the inlet orifice, the thin-film and the structural domains is used to illustrate the static performances of the proposed bearing. Based on the modeling method, the first generation of active bearing is realized using integrated leaf spring and a voice coil actuation. Finite element analysis validated the mechanical design, and experimental results showed a quasi-infinite passive static stiffness in open loop operation. In addition, the actuation ensured servo compliance of 3.4 μm/A. To investigate the dynamic performance namely stiffness, damping and actuation reactivity, this work presents a novel dynamic model encapsulating the fluid-structure interaction based on linear perturbation around a static operating point. A comprehensive sensitivity analysis illustrated the impact of the design variables on the dynamic response. Based on the numerical model and the requirement for proper actuation bandwidth, the 2nd generation pads are designed and tested. Experimental results validated the dynamic model, and the pad’s performance in terms of stiffness and damping. The active pads exhibit ultra-high stiffnesses, however, due to the compressibility of the air, negative damping is encountered. To overcome the negative damping leading to unstable system poles, a novel control architecture based on active inertial damping is illustrated using commercially available geophones. The… Advisors/Committee Members: Wegener, Konrad, Dual, J..

Subjects/Keywords: Aerostatic bearing; precision mechatronics; 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):

Maamari, N. (2019). Smart Active Aerostatic Bearing. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/431500

Chicago Manual of Style (16^th Edition):

Maamari, Nadim. “Smart Active Aerostatic Bearing.” 2019. Doctoral Dissertation, ETH Zürich. Accessed February 24, 2021. http://hdl.handle.net/20.500.11850/431500.

MLA Handbook (7^th Edition):

Maamari, Nadim. “Smart Active Aerostatic Bearing.” 2019. Web. 24 Feb 2021.

Vancouver:

Maamari N. Smart Active Aerostatic Bearing. [Internet] [Doctoral dissertation]. ETH Zürich; 2019. [cited 2021 Feb 24]. Available from: http://hdl.handle.net/20.500.11850/431500.

Council of Science Editors:

Maamari N. Smart Active Aerostatic Bearing. [Doctoral Dissertation]. ETH Zürich; 2019. Available from: http://hdl.handle.net/20.500.11850/431500

ETH Zürich

30. Marini, Marcello. Agent-Based Assessment of Future Demographics and Impact on Infrastructure Transition Needs.

Degree: 2020, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/432970

► Most World countries are currently facing an important transformation in demographic structure due to the overall ageing of the population, additionally in the recent years… (more)

▼ Most World countries are currently facing an important transformation in demographic structure due to the overall ageing of the population, additionally in the recent years an extreme increase of mobility, both physical and economical, has been observed, drastically increasing migration flows and accelerating the transformation of demographics. The changes in demographics are one of the primary sources of uncertainty for infrastructure developers and policy makers; different demographics have different behaviours and requirements, affecting the demand for infrastructure, services, housing, and impacting differently the social security system. Thus it is essential to understand the mechanisms and quantitatively assess the future evolution of demographics, accounting for the sensitivity to multiple interdependent factors in a holistic way. Typically the impact of demographics on infrastructure is assessed based on projections of past trends. This approach is not sufficient to predict effects of demographic change on infrastructure, since not accounting for changes in behaviour, due for example to ageing or changes in household structure. Recently, agent-based simulations are being used, but being computationally demanding are often limited to the observation of individual elements of behaviour at small scale. In the course of this work for the first time ever, a fully-coupled, high-resolution (1 meter), continental-scale agent-based model for population, dwellings, and jobs has been developed. The interlinked models are designed to run on a GPU framework, allowing for fast computations, making it possible to simulate the whole EU in less than 1 hour per simulated year. The results show how in Switzerland and EU migration is the primary driver for changes in demographics. Difference in demographics strongly affect development of housing within urban agglomerations, while young immigrant population contributes to the support of social security for Switzerland: if the annual immigration rates are limited to 50% of today’s rate, the social security system will become insolvent by 2027. Impact of different population densities are also observed in relation to public transport and disease transmission, the studies show also the effect of densification on commuting patterns and time, increasing up to 20% where new urban centres are established. Finally the simulations of the whole European population in the context of Brexit shows the re-distribution of migration flows towards UK, France, and Germany, while simultaneously future migration will decrease by 38%, posing important challenges in terms of infrastructure, support for social security and availability of workforce. In general, it is clear why today’s concerns related to immigration revolves towards overcrowding, but in future migrants will become a valuable asset to provide for social security support and workforce for most European countries. Thus, it is important to focus on the typology of migrants and favour the creation and growth of new families, to make the… Advisors/Committee Members: Abhari, Reza S., Mestras, Juan P., Chokani, Ndaona.

Subjects/Keywords: Agent-based modeling; simulation; 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):

Marini, M. (2020). Agent-Based Assessment of Future Demographics and Impact on Infrastructure Transition Needs. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/432970

Chicago Manual of Style (16^th Edition):

Marini, Marcello. “Agent-Based Assessment of Future Demographics and Impact on Infrastructure Transition Needs.” 2020. Doctoral Dissertation, ETH Zürich. Accessed February 24, 2021. http://hdl.handle.net/20.500.11850/432970.

MLA Handbook (7^th Edition):

Marini, Marcello. “Agent-Based Assessment of Future Demographics and Impact on Infrastructure Transition Needs.” 2020. Web. 24 Feb 2021.

Vancouver:

Marini M. Agent-Based Assessment of Future Demographics and Impact on Infrastructure Transition Needs. [Internet] [Doctoral dissertation]. ETH Zürich; 2020. [cited 2021 Feb 24]. Available from: http://hdl.handle.net/20.500.11850/432970.

Council of Science Editors:

Marini M. Agent-Based Assessment of Future Demographics and Impact on Infrastructure Transition Needs. [Doctoral Dissertation]. ETH Zürich; 2020. Available from: http://hdl.handle.net/20.500.11850/432970

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Open Access Theses and Dissertations