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A Model-Based System Engineering Approach to Support System Architecting Activities in Early Aircraft Design
Get PDFThe aviation industry aims to reduce its environmental footprint and meet ambitious environmental targets, prompting the exploration of novel aircraft concepts and systems, such as hybrid-electric or distributed propulsion. These emerging technologies introduce complexity to aircraft system architectures, requiring innovative approaches to design, optimization, and safety assessment, particularly for system architecting. Several aspects of system architecting specification and evaluation are typically performed separately, using different people and a mix of manual and model-based processes. Connecting these activities has the potential to make the design process more efficient and effective. This thesis explores how a Model-Based Systems Engineering (MBSE) specification environment can be structured and enriched to enable a better bridge to Multidisciplinary Design Analysis and Optimization (MDAO) and Model-Based Safety Assessment (MBSA) activities. The proposed MBSE approach focuses on enhancing system specifications, particularly for unconventional system architectures, which typically feature greater variability in early design stages. Using the ARCADIA/Capella MBSE environment, a multi-level approach is proposed to structure the system architecture specification and the Property Value Management Tool (PVMT) add-on is used to facilitate the bridge to other system architecting activities. In addition, a catalogue of modeling artifacts is established to facilitate the development of various hybrid-electric system configurations. The MDAO link mechanism is demonstrated with an example from the collaborative AGILE4.0 project. Two test cases demonstrate the implementation of the approach: a hybrid-electric propulsion system and associated sub-systems for the overall approach and the landing gear braking system for the model-based Functional Hazard Analysis (FHA), as an example of an MBSA activity. Overall, this thesis helps improve the integration and collaboration between engineers working on MBSE, MDAO, and MBSA. This better integration will help to reduce the development time and risk. Therefore, the presented thesis contributes to a more efficient aircraft development process, enabling the industry to tackle the emerging needs of unconventional aircraft systems and their integration
From the Traditional Courtyard Houses to Large-Scale Residential Buildings in Beijing - How Modern Development Impacted a Unique Architectural Heritage and Mode of Living A Design Research - Creation Perspective
Get PDFBeijing, a city steeped in history and architectural grandeur, has undergone significant changes due to modernization and globalization. The traditional housing — Siheyuan [courtyard houses], symbolic of its cultural heritage, have witnessed extensive deterioration, gradually changed to Soviet-style residences and later evolved into modern high-rise dwellings.
This thesis aims to conduct a comprehensive analysis of Beijing's housing transformation over the last century and clarify the underlying reasons for this change. Also, this research goes beyond the visual dimension of housing to explore the cultural identity that is intrinsically linked to housing in Beijing. To achieve these objectives, a hermeneutic approach is employed. The research encompasses a literature review, typology study, and interviews. Additionally, a creation proposal is developed to enhance the understanding of the impact of modern development on China's capital city. The creation takes the form of a visually compelling photo montage, aiming to raise awareness among designers and architects about the need to preserve Beijing's unique cultural heritage embedded within its traditional housing.
In conclusion, this study puts forth a series of recommendations and design guidelines that provide valuable tools for future development in Beijing. These proposals emphasize the preservation of cultural heritage within the residential design, ensuring that the city's rich traditions are safeguarded for generations to come.
Keywords: Beijing, housing transformation, courtyard house, Soviet-style compound, modern dwelling, cultural identit
Design for the Art of Learning: Defining Challenges for Maker-Driven Design Activities and Design Education in Secondary Schools
Get PDFThis thesis reflects on strategies used to facilitate didactic interactions between design research-creation and maker experiences in a secondary school. The author uses maker-driven design activity as a hybrid term to define educational activities that integrate critical making, sustainable action, and creative uses of technology. Two projects are described to exemplify the challenges and qualities of this didactic approach. The careful use of design constraints and observations of patterns of concern, such as process avoidance, are essential in understanding the qualities necessary for a meaningful design experience in the context of school. The author uses observations of maker-driven design activity situated in a school Fab Lab to inform guideposts for future research-creation infusing creative-technical learning with design literacy. This thesis is intended for designers, teachers, and researchers interested in creative and interdisciplinary learning experiences in what is broadly labelled as design for the art of learning
Textile as Image: Mediation, Materiality, and the Senses in Textile Research
Get PDFThis research-creation thesis moves between theory and practice to inquire into the mediation and transformation of everyday textile materials into visual images. Central concerns are the image and its connection to increasing textile overproduction. Design techniques informed by handmaking and embodied practices are combined with interdisciplinary approaches from media theory and sensory studies to generate discursive design artifacts. The translation of the tactile senses is explored through image-making, alongside a simultaneous historical investigation of the textile through a variety of its changing representational states. Through three distinctive mediums—rag paper, analog image, and networked digital media image—this project examines the affective relationships between wearer and worn, the textile and the body, and the alteration of their connections through representation and symbolisation.
A series of studies that re-imagine everyday textiles and garments through image are presented. Through this practice-based inquiry the potential of research-creation to contribute towards alternative and more holistic ways of making and sharing fashion and textile materials is explored
Methodology for the Design and Predictive Control of Active Solar Windows with Radiant Floor Heating in Perimeter Zones
Get PDFThis study presents a model for designing and controlling energy-positive facades with radiant floor heating in perimeter zones of commercial buildings. The model integrates bifacial semi-transparent photovoltaic windows, motorized venetian blinds, and hydronic radiant floor heating systems. These components are modeled to optimize energy performance within occupant comfort constraints during the heating season. By implementing near-optimal control strategies for room air temperature setpoints, blind tilt angles, and controlled lighting loads, the perimeter zones achieve improved energy flexibility, efficiency, and thermal and visual comfort. Key design variables such as slab thickness, window-to-wall ratio, and packing factor were analyzed parametrically to determine optimal ranges when subjected to near-optimal control strategies. To evaluate the effectiveness of different control strategies, a specially designed and instrumented test-room at the Future Buildings’ Lab (FBL) was used as a case study. Balancing energy performance with occupant comfort is crucial, as prioritizing one aspect may compromise the other. The combined control of these systems demonstrates enhancements in both energy performance and occupant comfort across various design scenarios. By implementing near-optimal control of the room air setpoint and the blind tilt angle the heating efficiency can improve by 39.6%, the BEFIP was 94.8% and 96.8% in the morning and evening peak periods, all while maintaining occupant comfort on a cloudy and mild day in the heating season. The addition of active solar windows further improves the energy flexibility of the zone. Similarly, in limiting
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weather conditions, such as very cold and cloudy days, the system may achieve significant energy flexibility, reduce energy costs, while maintaining thermal comfort
Poromechanical Analysis of Deeply Drilled Wellbores for Geo-energy Production
Get PDFGeo-mechanical analysis and ensuring wellbore stability are paramount for the success of deep geo-energy production projects. The present study addresses the complex challenges arising from geological formations comprising laumontite-rich rocks, fault zones, and fractured rock formations, which significantly influence the mechanical behavior and stability of wellbores.
Tight glutenite reservoir formations containing laumontite minerals pose challenges for geo-energy production due to their complex stress-sensitive mechanical behaviors. With an increase in the confining pressure, there is a transition from the shear dilation to the consolidated compaction in laumontite-rich formations. This study presents the finite element modeling of constitutive behaviors of laumontite-rich rocks using a thermodynamic-consistent plasticity model. Poromechanical analysis is performed to investigate plastic zone development around a borehole in an overpressured reservoir along with a comparison to traditional plastic constitutive models. The findings contribute to understanding and addressing the challenges of wellbore stability in laumontite-rich formations for geo-energy projects.
The wellbore stability of deeply buried petroleum wells in fault zones is another major concern of deep drilling projects. This study also focuses on a super-deep petroleum well drilled into an Ordovician limestone reservoir formation with a buried depth of about 8000 meters located in the Tarim Basin, China. Laboratory tests and dual-porosity theories of poromechanics are employed to derive stress and pore pressure distributions in a limestone formation surrounding the wellbore. The analysis highlights the significance of borehole azimuth and the selection of an optimal well trajectory, considering the strength properties of both the rock matrix and fractures.
Geological formations in the Canadian Shield with natural fractures in fault zones offer enhanced permeability for geothermal development. However, ensuring wellbore stability during drilling and energy production is crucial. The Finite Element modeling is employed to assess the performance of boreholes in fractured rock formations under non-isothermal conditions at a potential deep geothermal site in northern Canada. The analysis considers plastic yielding in the rock matrix and sliding potential along fractures, accounting for the cooling effect. Findings highlight the importance of managing the cooling effect to avoid excess pore pressure build-up and sliding along tilted fractures.
Collectively, this research provides a comprehensive understanding of wellbore stability and geomechanical behaviors in diverse geological formations. The findings contribute to the development of strategies and guidelines for safe and efficient geo-energy production in challenging geological environments
Integer and Fractional Charge Transfer in the Doping of Poly- and Oligothiophenes
Get PDFIn the p-doping of organic semiconductors with small molecular dopants integer-charge transfer forming ion-pairs (IPAs) and fractional charge transfer through the formation of ground state charge-transfer complexes (CPXs) have been identified as competing fundamental processes. IPAs and CPXs differently affect the performance of doped organic electronic devices, however, the conditions leading to either phenomenon are still to be fully understood. This thesis focuses on the conjugated polymer poly(3-hexylthiophene) (P3HT) p-doped with the strong molecular electron acceptor tetrafluorotetracyanoquinodimethane (F4TCNQ) and its derivatives of lower electron affinity (F2TCNQ, FTCNQ, TCNQ). Under consideration of their different dopant strengths, the role of the critical dopant concentration promoting the one phenomenon over the other is investigated. Cyclic voltammetry is used to determine ionization energy and electron affinity values of the materials involved to gauge their influence on IPA and CPX occurrence, as identified through optical and vibrational spectroscopy. Supported by electrostatic modeling taking into account the width of the Gaussian density of states (DOS) related to the highest occupied molecular orbital in P3HT, DOS broadening upon doping is considered to explain IPA formation with weaker dopants. Grazing incidence x-ray diffraction is employed toassess the interplay between the supramolecular structure and the two doping phenomena, supporting the hypothesis that a CPX polymorph can occurs that effectively prevents IPA formation for a given host-dopant stoichiometry. Conductivity data on doped films highlights the application-related impacts of these findings. Finally, for a series of custom thiophene oligomers of different lengths, instead of P3HT, the common observation of CPX formation being promoted in the molecular doping of (small) conjugated molecules is investigated. The threshold of transition into the doping phenomenology of the polymer limit is observed at a chain length of 10 thiophene units - a parameter to be considered when employing oligothiophene semiconductors in applications demanding molecular doping. Overall, due the multi-technique approach targeting doping phenomena and mechanisms of a prototypical polymer and oligomer equivalents doped with a systematic series of p-dopants, the database presented here provides a consistent and coherent point of reference for assessing the performance and phenomenology encountered with novel dopants
Molecular Dynamics Simulations of the Water-Soluble Chlorophyll-binding Protein : Identifying Structural Features Responsible for Spectral Dynamics
Get PDFPhotosynthesis is the process responsible for nearly all life on Earth. Pigment-protein complexes, fundamental components of photosynthesis, are the subject of many studies to better understand this process and develop novel approaches to harvesting light energy. Observations of line shifts in the single-molecule optical spectra of such complexes through optical spectroscopy indicate structural changes in the chlorophyll environment. Nonetheless, the specific molecular elements responsible for the observed spectral dynamics remain largely unknown. In this project, we have studied the Water-Soluble Chlorophyll-binding Protein to elucidate some of these molecular-level mechanisms. Molecular Dynamics simulations of the complex were conducted at T1 = 300 K and T2= 165 K for 1 μs. The vicinity of the chlorophylls was determined by computing the pigments contact map. At 300 K, small conformational changes were discovered, involving side chain rotations of certain residues, primarily the non-polar Leucine and Valine. From those observations, the protein free energy landscape associated with this generalized coordinate was mapped, and the heights of the energy barriers were determined at around 1000-1500 cm−1. This range of values agrees with experimental results. To gain a deeper understanding of these residues dynamics, we performed Dynamical Network Analysis. It revealed high motion correlations between residues located in close proximity, suggesting a similar rate of conformational change among these residues. Through network connectivity analysis, we found a similar side chain rotation in the same residue in each monomer located farther from the pigments. The energy barrier height associated with this residue is also consistent with experimental results
Mixed Reality and Force Feedback Haptic Tools for Improved Surgical Planning
No full textPreoperative evaluation of patient-specific anatomical data is a preliminary step in any surgical
procedure. Medical imaging and visualization of patient-specific anatomical data are critical com�ponents of this step and can be presented as 2D images or 3D objects. While 2D images have been
used in traditional systems, 3D visualization of this data provides more comprehensive information
about the organ under treatment, so it is important to note that exploration and comprehension of the
data may be improved when intuitive interaction and visualization methods are used. Meanwhile,
haptic tools and augmented reality in different medical systems have shown promising improve�ments to the overall system performance in terms of enhancing the sense of touch, providing 3D
perspectives, and, allowing for more intuitive interaction techniques.
In this study, we explore the use of 3D visualization of anatomy on screen and in AR and
different interaction techniques in the context of pre-operative planning. Specifically, we compare
planning using the traditional 2D monitor and mouse, a monitor with the 3D Systems Touch X
force feedback haptic device, and an augmented reality head-mounted display (using the HoloLens
2) which uses gesture-based interaction.We performed two user studies, one with novices and one
with experts. The user studies involved interacting with 3D anatomical data in the context of three
surgical planning scenarios: (1) heart valve repair, (2) hip tumor resection, and (3) pedicle screw
placement. Our findings suggest that our users preferred the AR system for the pedicle screw
placement and for the other two cases, and reported that AR provides the best depth perception
compared to the other two platforms. Our novices preferred the haptic system for hip tumor planning
while experts preferred the mouse and keyboard (2D) system
A Dance of Neural Rhythms: Coupling of Slow Oscillations and Spindle Activity During Sleep, in Relation to Memory and Ageing
Get PDFSleep undergoes both quantitative and qualitative changes across the lifespan, which accompanies age-related declines in memory. Contemporary research suggests that synchronized cross-frequency coupling (CFC) of slow oscillations (SO) and spindles during sleep is a neural mechanism of overnight memory consolidation, and it has been hypothesized that an age-related “de-coupling” may contribute to memory impairments in older adults. However, evidence for this ageing hypothesis is currently lacking, as most available studies of SO-spindle CFC and memory focus on young adults, with few studies available to directly compare younger and older groups.
The goal of my dissertation is to enhance current thinking about SO-spindle CFC and its relations with ageing and overnight memory consolidation. This work includes two interrelated studies, both examining SO-spindle CFC during sleep in relation to performance on a sleep-dependent declarative memory task. The first study, with 25 healthy seniors, showed that SO-spindle CFC was stable across two recording nights, and that a slow spindle coupling phase closer to the SO up-state predicted better memory consolidation. An exploratory analysis also highlighted potential interactive effects between distinct CFC measures in predicting memory. My second study builds on the analyses from Study 1 with a new sample of 16 older adults compared to 16 young adults, all who completed an expanded 3-night protocol that included a similar memory task and a cognitive control task. This second study showcased age-group differences in coupling during sleep but did not find similarly strong evidence for relations between CFC and memory.
Overall, this work demonstrates 1) a preserved association between certain measures of CFC during sleep and memory in older adults; 2) that coupling dynamics may differ between younger and older adults, but the overall magnitude of coupling may not; and 3) how relations between CFC, ageing, and memory can vary across distinct analytic contexts. Results are discussed in reference to the impact of ageing on brain oscillations and CFC, distinctions in the methods between my two studies as compared to the extant literature, and the impact of even small changes in signal processing decisions on coupling metrics and their association with memory and ageing