http://hdl.handle.net/10900/42133 Thu, 02 Jul 2026 18:38:51 GMT 2026-07-02T18:38:51Z http://hdl.handle.net/10900/181230 Haptify: A Measurement-Based System for Quantifying the Quality of Haptic Interfaces Fazlollahi, Farimah Die Dissertation ist gesperrt bis zum 05. März 2028 !; Grounded force-feedback (GFF) devices, exoskeletons, and other haptic robots modulate human movement through carefully engineered mechanical, electrical, and computational designs. Given their significant societal potential and often high cost, it is essential to fairly and efficiently assess the quality of these intimate cyber-physical interfaces. However, existing device specifications and low-level performance metrics often fail to capture the nuanced qualities that expert users perceive during hands-on experimentation. To address this gap, this thesis introduces Haptify, a comprehensive benchmarking system that can thoroughly, fairly, and noninvasively evaluate GFF haptic devices. Haptify integrates multiple sensing modalities---a seven-camera optical motion-capt\-ure system, a custom-built 60-cm-square force plate, and an instrumented end-effector that can be adapted to different devices---to record the interaction between the human hand, the device, and the ground during both passive and active experiments. With this setup, users hold the device end-effector and move it through a series of carefully designed tasks while Haptify measures kinematic and kinetic responses. From this process, we establish six key ways to assess GFF device performance: workspace shape, global free-space forces, global free-space vibrations, local dynamic forces and torques, frictionless surface rendering, and stiffness rendering. These benchmarks enable systematic evaluation and comparison across devices. We first apply Haptify to benchmark two GFF devices produced by 3D Systems: the widely used Touch and the more expensive Touch X. Results reveal that the Touch X offers a slightly smaller workspace than the Touch, but it produces smaller and more predictable free-space forces, reduced vibrations, more consistent dynamic forces and torques, and higher-quality rendering of both frictionless surfaces and stiff virtual objects. To further validate and extend our approach, we conducted a user study with sixteen expert hapticians who used Haptify to evaluate four commercial GFF devices: Novint Falcon, Force Dimension Omega.3, Touch, and Touch X. Experts tested the devices in unpowered mode and across five representative virtual benchmark environments, providing extensive quantitative ratings and qualitative feedback. We distilled recurring themes from their input and analyzed correlations between expert opinions and sensor-based measurements. Our findings show that expert judgments of fundamental haptic quality indicators align closely with the metrics derived from Haptify. Moreover, device performance both unpowered and in active benchmarks can be used to predict its suitability for more complex applications, such as teleoperated surgery. By linking expert assessments with external measurement data, this thesis establishes a combined qualitative--quantitative framework for benchmarking haptic robots. This approach not only enables fair comparison across diverse devices but also establishes a direct connection between objective measurements and the subjective expertise of experienced hapticians. In doing so, it lays the foundation for more rigorous, transparent, and application-relevant evaluation of haptic technologies. Sun, 05 Mar 2028 00:00:00 GMT http://hdl.handle.net/10900/181230 2028-03-05T00:00:00Z http://hdl.handle.net/10900/181222 Analysis and Identification of Per- and Polyfluoroalkyl Substances (PFAS) from Aqueous Film Forming Foams (AFFF) and their Products of Incomplete Destruction using High Resolution Mass Spectrometry Schüßler, Melanie Per- and polyfluoroalkyl substances (PFAS) are a large group of anthropogenic chemicals, produced since the 1940s, which are characterized by unique properties such as high stability, hydrophobicity as well as oleophobicity and surface activity, that make them attractive for a wide range of industrial applications. Their high stability results from the strength of the C-F bond which makes them also very persistent in environmental matrices. For some PFAS, such as perfluoroalkyl acids (PFAAs), toxic effects have been reported, leading to their ban and restriction. Although PFAAs are no longer used in industry, they can still be formed as terminal products of biotransformation of polyfluorinated, non-restricted PFAS precursor compounds. Extensive use of PFAS led to their world-wide distribution in all environmental compartments, and through their use in aqueous film forming foams (AFFF) they can be discharged directly into the environment, resulting in heavily contaminated hot-spots. PFAS used in AFFF do not have to be disclosed by the manufacturers, can show diverse chemical structures, be of anionic, zwitterionic and cationic nature and may be also transformed to PFAAs under environmental conditions. To prevent and manage threats for drinking water resources, AFFF contaminated sites should be efficiently remediated. A prerequisite for effective remediation is a well-characterized extent of the contamination. Since analytical standards are often unavailable for many PFAS, non-target screening (NTS) by high-resolution mass spectrometry (HRMS) can reveal the contamination, and, through semi-quantification (quantitative NTS, qNTS), even estimate its magnitude. Thermal remediation techniques have been discussed as viable options for PFAS remediation, however little is known about thermal behaviour of PFAS and formation of potentially toxic products of incomplete destruction (PIDs), especially for AFFF PFAS. Therefore, in the first part of this dissertation, soil and groundwater from an AFFF contaminated field site in Germany were subjected to a newly developed qNTS workflow, revealing the presence of 124 individual PFAS from 42 subclasses in the soil. The analysis showed that the contamination was diverse and from potentially different AFFF formulations due to fire-fighting acitvities. Semi-quantification revealed that more than 50% of the identified contamination would have been missed without the qNTS approach. Also, most of the contamination was still present in the top meter of the soil, which was attributed to the presence of zwitter- and cationic- precursors which have strong retention in soil due to electrostatic effects. Nevertheless, mostly short-chained, mobile PFAAs were identified in deeper soil layers and groundwater, highlighting the threat to drinking water resources. In the second part of this work, thermal transformation and desorption behaviour of 6:2 FTSAm-Pr-B, the most abundant compound in the soil from the Reilingen field site, was investigated to evaluate the potential of thermal remediation methods to AFFF contaminated soil. Results demonstrated, that 6:2 FTSAm-Pr-B can produce a variety of PIDs in both a closed and open system-setup and that its transformation can be initiated at temperatures ≥ 150 °C. However, a mass balance (MB) approach revealed a gap in the mass balance at temperatures > 150 °C, indicating the presence of additional PIDs that were not detectable with the applied methods. In an open system, no thermal desorption (TD) of 6:2 FTSAm-Pr-B was observed. Instead, transformation was the dominant process. Temperatures, at which transformation was initiated as well as reaction kinetics were found to be strongly dependent on the sorbent material. Reaction kinetics were fastest with granular activated carbon (GAC) and slowest with organic carbon (OC) rich soil, indicating that GAC may facilitate and OC may hinder the reaction. It was further shown that some PIDs of FTSAm-Pr-B were more stable than their precursors and may also be able to thermally desorb. In conclusion, this work demonstrates the importance of quantitative NTS workflows for the characterization of complex contaminations, such as the Reilingen field site. Furthermore, the evaluation of the thermal transformation of 6:2 FTSAm-Pr-B revealed that the application of thermal remediation strategies to contaminated soils is possible, but not straightforward, as a variety of PIDs must be considered and monitored, even in low-temperature applications, aiming for thermal desorption.; Die Dissertation ist gesperrt bis zum 31. Dezember 2026 ! Thu, 31 Dec 2026 00:00:00 GMT http://hdl.handle.net/10900/181222 2026-12-31T00:00:00Z http://hdl.handle.net/10900/181205 Functional Lateralization of Number Processing: from magnitude, individual and cultural perspective Bahreini, Narjes Die Dissertation ist gesperrt bis zum 27. Mai 2026 !; Abstrakt Das Verständnis von und der Umgang mit Zahlen ist eine der am weitesten entwickelten kognitiven Fähigkeiten. Während die numerische Kognition umfassend untersucht wurde, bleibt die Frage nach ihrer funktionellen Lateralisierung unbeantwortet. Führende Modelle, wie das Triple-Code-Modell der Zahlenverarbeitung, gehen von einer bilateralen Repräsentation der Zahlenverarbeitung im intraparietalen Sulcus (IPS) aus. Infolgedessen hat die Forschung die Frage der funktionellen Lateralisierung der Zahlenverarbeitung weitgehend vernachlässigt. Die vorliegende Dissertation befasst sich mit diesem Thema, indem sie die funktionelle Lateralisierung der Zahlenverarbeitung aus drei Perspektiven untersucht: numerisch, individuell und kulturell. Die Dissertation umfasst eine Stichprobe von N = 162 Erwachsenen, um das Größenverständnis bei 54 deutschen Rechtshändern, die Händigkeit im Vergleich zu 54 deutschen Linkshändern und die Leserichtung im Vergleich zu 54 iranischen Rechtshändern zu untersuchen. In einem Messwiederholungsdesign wurde anodale transkranielle Gleichstromstimulation (tDCS) auf den rechten IPS, auf den linken IPS und in einer Scheinbedingung angewendet. Die Aufgabe bestand in dem Vergleich einstelliger und zweistelliger Zahlen. Die Studien wurden präregistriert und konfirmatorische Analysen lieferten keine Evidenz für eine funktionelle Lateralisierung aus numerischer, individueller und kultureller Sicht. Explorative Analysen hingegen lieferten Einblicke in numerische, individuelle und kulturelle Einflüsse auf die Repräsentation von Zahlen im IPS. Studie 1 untersuchte, ob das Größenverständnis bei Zahlen die hemisphärische Lateralisierung beeinflusst. Konfirmatorische Analysen zeigten keinen direkten Lateralisierungseffekt von tDCS auf die Zahlenverarbeitung. Explorative Analysen deuten jedoch darauf hin, dass die Stimulation des rechten IPS die Verarbeitung einstelliger Zahlen verlangsamte, was auf eine wichtigere Rolle des linken IPS für einstellige Zahlen hinweist. Studie 2 untersuchte die Rolle individueller Unterschiede, insbesondere der Händigkeit, bei der Zahlenverarbeitung. Unsere konfirmatorischen Analysen ergaben keine 4 signifikanten Unterschiede in der Zahlenverarbeitung zwischen Rechts- und Linkshändern, was die Annahme des Triple-Code-Modells einer bilateralen Repräsentation im IPS bestätigt. Explorative Analysen ergaben jedoch, dass die Stimulation des linken IPS die Zahlenverarbeitung bei Linkshändern begünstigt, während die Stimulation des rechten IPS divergierende Effekte hatte: Begünstigung bei Rechtshändern (für einstellige Zahlen), aber Beeinträchtigung bei Linkshändern (für zweistellige Zahlen). Diese Ergebnisse legen nahe, dass die dominante Hemisphäre die Zahlenverarbeitung modulieren kann. Studie 3 untersuchte kulturelle Einflüsse auf die Zahlenverarbeitung und konzentrierte sich dabei auf die Leserichtung und die Gewohnheiten des Fingerzählens bei Iranern (von rechts nach links) und Deutschen (von links nach rechts). Konfirmatorische Analysen ergaben keinen signifikanten Effekt der kulturellen Leserichtung oder Fingerzählgewohnheiten auf die Lateralisierung. Explorative Analysen zeigten jedoch, dass die tDCS-Stimulation die Zahlenverarbeitung bei Iranern stärker begünstigte als bei Deutschen, was darauf hindeutet, dass kulturelle Faktoren die numerische Kognition auf neuronaler Ebene modulieren können. Diese Dissertation verfeinert theoretische Modelle der numerischen Kognition und unterstreicht die Notwendigkeit eines differenzierten Verständnisses der funktionellen Lateralisierung, wobei vor einer Übergeneralisierung der Ergebnisse über verschiedene numerische Aufgaben, individuelle Unterschiede und kulturelle Kontexte hinweg gewarnt wird. Die Ergebnisse zeigen, dass spezifische Faktoren wie Größenverständnis, Händigkeit und Kultur die Zahlenverarbeitung auf komplexe Weise modulieren können.; 1 Abstract Understanding and manipulating numbers is one of the most advanced cognitive abilities. While numerical cognition has been extensively studied, the question of its functional lateralization remains unresolved. Leading models, such as the triple code model of number processing, propose a bilateral representation of number processing in the intraparietal sulcus (IPS). As a result, research has largely neglected the question of functional lateralization in number processing. The current dissertation addresses this issue by exploring functional lateralization in number processing from three perspectives: numerical, individual, and cultural. The dissertation involves a sample of N = 162 adults, to study magnitude in 54 German right-handers, to study handedness in comparison to 54 German left-handers, and to study reading direction in comparison to 54 Iranian right-handers. In a within-subject design, anodal transcranial direct current stimulation (tDCS) was applied to the right IPS, to the left IPS, and in a sham condition. The task consisted of single-digit and two-digit number comparison. The studies were preregistered, and confirmatory analyses did not reveal evidence for functional lateralization from the numerical, individual, and cultural perspectives. However, exploratory analyses provided insights into numerical, individual and cultural influences on the representation of numbers in the IPS. Study 1 investigated whether magnitude size influences hemispheric lateralization. Confirmatory analyses showed no direct lateralization effect of tDCS on number processing. However, exploratory analyses suggested that right IPS stimulation slowed single-digit number processing, indicating a more prominent role of the left IPS for single-digit numbers. Study 2 examined the role of individual differences, specifically handedness, in number processing. Our confirmatory analyses found no significant differences in number processing between right- and left-handers, supporting the triple code model’s assumption of bilateral IPS involvement. However, exploratory analyses revealed that left IPS stimulation facilitated number processing in left-handers, while right IPS stimulation had divergent effects: facilitation in right-handers (for single-digit numbers) 2 but impairment in left-handers (for two-digit numbers). These findings suggest that the dominant hemisphere may modulate number processing. Study 3 explored cultural influences on number processing, focusing on reading direction and finger counting habits in Iranians (right-to-left) and Germans (left-to-right). Confirmatory analyses found no significant effect of cultural reading direction or finger counting habits on lateralization. However, exploratory analyses revealed that tDCS stimulation facilitated number processing more in Iranians than Germans, suggesting that cultural factors may modulate numerical cognition at a neural level. This dissertation refines theoretical models of numerical cognition and emphasizes the need for a nuanced understanding of functional lateralization, cautioning against overgeneralizing results across different numerical tasks, individual differences, and cultural contexts. The findings highlight that specific factors such as magnitude, handedness, and culture can modulate number processing in complex ways. Thu, 27 May 2027 00:00:00 GMT http://hdl.handle.net/10900/181205 2027-05-27T00:00:00Z http://hdl.handle.net/10900/181105 Finite Element Analysis for bulk–surface Partial Differential Equations in evolving Domains Edelmann, Dominik This dissertation studies the numerical approximation of various partial bulk–surface differential equations in time-dependent domains. The main interest is an application to a model of tissue growth which is a slight modification of a model presented by Eyles, King & Styles [2019]. The model couples a Poisson equation in the time-dependent domain with a forced mean curvature flow of the free boundary surface, with nontrivial bulk–surface coupling in both the velocity law of the evolving boundary surface and the boundary condition of the Poisson equation. Thu, 25 Jun 2026 00:00:00 GMT http://hdl.handle.net/10900/181105 2026-06-25T00:00:00Z