This thesis serves as proof of concept for the tensile strength simulation-based nonwoven material design. Objective is the adjustment of the parameters of an underlying production process with regard to a desired tensile strength behavior (optimization). As an example, we focus on the nonwoven airlay production and consider a thermobonding procedure for the consolidation of the nonwoven fabrics. To be able to map production parameters to the associated tensile strength behavior, we present a model-simulation framework composed of a model for the nonwoven fiber structure generation and a model for the nonwovens’ mechanical behavior under vertical load. The model for the fiber structure generation replicates the stochastic fiber lay-down of the airlay production and results in a random three-dimensional fiber web. This web is consolidated using a virtual bonding procedure that mimics the thermobonding of the nonwoven material. The topology of the resulting adhered fiber structure can be described by a graph, which serves as basis for the subsequent tensile strength simulation. The model used for this purpose describes the mechanical behavior of the material at fiber network level. Therefore, the considered fiber structure sample is interpreted as truss and the fiber connections are equipped with a nonlinear material law, which allows to describe the elastic phase of the nonwovens’ tensile strength behavior. The existence and uniqueness of a solution to the model as well as its numerical treatment are discussed. Moreover, we present data reduction strategies that enable more efficient simulations by removing fiber structure parts that do not contribute to the tensile strength behavior. As it becomes evident from the numerical experiments, a single tensile strength simulation for a production-like virtual sample is already computational demanding. Costs accumulate further, since Monte-Carlo simulations are required to account for the randomness in the fiber structure generation. Thus, direct simulations provide an infeasible basis for the nonwoven material design. This motivates the use of a predictive surrogate for optimization. Therefore, we consider regression-based approaches at different levels of information within the simulation framework. It turns out that the coupling of a polynomial model, for the fiber structure feature inference, with a linear one, for the stress-strain curve inference, yields accurate predictions. Once trained, the regression models allow for efficient evaluations and thus represent a suitable surrogate for the nonwoven material design. In this context, we discuss two exemplary problems of interest for the application: First, a tracking-type problem that aims to find the production parameters that result in a desired tensile strength behavior, expressed in terms of stress-strain curves. Second, an in-corridor maximization problem, which aims to identify the production parameters that maximize the probability of ending up in a specified stress-strain corridor.

Transnational protest movements continue to expose the enduring legacies of colonial exploitation and institutionalised racism within and beyond European cities. They foreground the systemic conditions under which Black lives are rendered disproportionately vulnerable to premature death. In doing so, they expose the enduring entanglements of racial capitalism, state violence and spatial exclusion. Through their ongoing political agitation these movements highlight the need for spatio-temporally situated and relationally embedded engagements with Black urban lives. My thesis responds to that call by examining place-making practices of enclosure and refusal throughout Black London’s post-World War II development. Grounded in the ethnographic narrative of “being halfway while shooting”, I explore how Black lives are enclosed by institutional racism, how this enclosure is spatialised and how Black and differently racialised Londoners refuse these spatial enclosures through everyday and collective place-making practices. At the intersection of structural constraint and the desire to enact Black freedom in London, I specifically foreground the emergence of fugitive place-making practices. Conceptually, I bring (critical) urban geography scholarship, Black studies and Black (British)Geographies scholarship into conversation. I develop “being halfway while shooting” as a relational concept that foregrounds the production of racialised urban knowledges, the multiplicity of Black enclosures, and the plurality of place-based strategies committed to refusal. I do so by stressing the relevance of Black fugitive thinking to account for the ongoing refusals that mark the relationship between Blackness and the British city. Methodologically, I adopt a research-activist ethnographic approach, grounded in my long-term engagement with a housing campaign in East London that organises around the housing needs of London’s racialised and gendered urban poor. Using qualitative methods - archival research, interviews, (non-)participant observations, document and media analysis - I embed contemporary struggles into long and ongoing histories of racial-capitalist urban development as well as Black and multi-ethnic refusal. The empirical chapters trace place-making practices of enclosure and refusal across London’s post-World War II urban development. By examining the aftermath of urban revolts and changing urban welfare regimes, I explore how racialised urban governance has been historically materialised in and through the city. At the same time, I foreground how within this racialised construction of the British city, Black and differently racialised Londoners continue to hold open the possibility of refusal through places in which communal care and self-determination can be enacted. I then turn to the struggle over housing in East London, showing how contemporary processes of racialised dehumanisation and ongoing displacement are both historically rooted and actively contested. In the final empirical chapter I accentuate the relevance of these findings for German-speaking critical urban geography debates. The research shows that racial capitalist urbanism reproduces enclosures through practices of value extraction, spatial displacement, and the policing of Black subjectivities. In response, Black and differently racialised Londoners engage in fugitive place-making. Rooted in communal care, political organisation, collective education and cultural affirmation, these practices reassert Black presence and belonging. They offer an enduring mode of place-based refusal and the ongoing possibility to stay in the city differently. These findings not only demonstrate the academic significance of my research but also underscore the urgent need to support the place-making practices of Black and differently racialised urban communities, who continue to refuse the racialised enclosure of the British city from within. From these empirical insights, I propose the concept of a fugitive sense of place - a theoretical lens that accounts for the racialised reproduction of urban space and the transformative place-making practices of those who refuse its logics. Rather than offering prescriptive policy recommendations, I call for a reorientation of urban geographical enquiry by centring Black spatial practices, knowledges and imaginations. Through the lens of “being halfway while shooting”, I argue for a rethinking of human habitation and urban theory through the lived experiences of Black survival and refusal. Attending to a fugitive sense of place, I propose new avenues for human geography research to explore how fugitive place-making practices reshape the meanings, conditions, and possibilities of urban life.

The role of implicit motives for affective, cognitive and behavioral processes has been a focal part of psychological research for decades. Yet, the majority of research in this field has been concentrated on processes involving implicit motives in adulthood. The systematic investigation of developmental correlates of implicit motives remains largely uncharted. The studies cumulated in this thesis aim to add to the sparse research on implicit motives in childhood and adolescence. Specifically, the development of the implicit power motive in the transition of middle to late childhood as a function of parenting behavior (Chapter 4), the predictive value of the implicit achievement motive for objective swimming performance in children and adolescents (Chapter 5) and the role of motive congruence for successful goal realization in adolescent samples across two cultures (Chapter 6) were investigated. Results of Study 1 (Chapter 4) indicate a negative longitudinal association of authoritarian parenting with the implicit power motive in children that is moderated by children’s perception of psychologically controlling parenting. Study 2 (Chapter 5) extends existing research on the assumed positive association of the implicit achievement motive and sports performance and demonstrates the moderating role of competitive anxiety on this association. Finally, Study 3 (Chapter 6) illustrates a moderating effect of implicit motives on the association of goal commitment and successful goal realization in German and Zambian adolescents, however, this effect was only observed in the domain of power motivation. Findings from all three studies are discussed in the context of the significance of implicit motives for psychological research.

This dissertation examines how individuals unlock their personal power by investigating individual differences in self-regulation, in particular, how situational conditions interact with the personality dispositions of action versus state orientation. Action-oriented individuals are well able to regulate their affective states and to bridge the intention–behavior gap, showing initiative, implementing demanding intentions, and resisting temptations. State-oriented individuals, by contrast, often struggle to regulate affect and experience difficulties enacting intentions, especially under demanding conditions, tending to hesitate and ruminate. While extensive research has highlighted the advantages of action orientation across various domains such as education and health, this thesis challenges the prevailing one-sided perspective that presents action orientation as inherently superior and frames state orientation negatively. Drawing on Personality Systems Interactions theory, the dissertation adopts a dynamic view that understands these dispositions as context-sensitive rather than fixed. The central assumption is that action and state orientation each require different kinds of situational conditions to fully unlock their potential. Across six empirical studies (overall N = 1,067) using a multimethod approach that combines experimental and survey-based research in diverse populations and contextual settings, this dissertation examines (1) action and state orientation as distinct dispositions, (2) their dynamic interaction with situational factors, and (3) ways to support each in mobilizing personal power. Overall, the findings show that each disposition offers unique advantages - they simply require different situational conditions for their potential to unfold.

Bilevel problems are optimization problems for which parts of the variables are constrained to be an optimal solution to another nested optimization problem. This structure renders bilevel problems particularly well-suited for modeling hierarchical decision-making processes. They are widely applicable in areas such as energy markets, transportation systems, security planning, and pricing. However, the hierarchical nature of these problems also makes them inherently challenging to solve, both in theory and in practice. In this thesis, we study different nonlinear problem settings for the nested optimization problem. First, we focus on nonlinear but convex bilevel problems with purely integer variables. We propose a solution algorithm that uses a branch-and-cut framework with tailored cutting planes. We prove correctness and finite termination of the method under suitable assumptions and put it into context of existing literature. Moreover, we provide an extensive numerical study to showcase the applicability of our method and we compare it to the state-of-the-art approach for a less general setting on suitable instances from the literature. Furthermore, we discuss challenges that arise when we try to generalize our approach to the mixed-integer setting. Next, we study mixed-integer bilevel problems for which the nested problem has a nonconvex and quadratic objective function, linear constraints, and continuous variables. We state and prove a complexity-theoretical hardness result for this problem class and develop a lower and upper bounding scheme to solve these problems. We prove correctness and finite termination of the proposed method under suitable assumptions and test its applicability in a numerical study. Finally, we consider bilevel problems with continuous variables, where the nested problem has a convex-quadratic objective function and linear constraints. We reformulate them as single-level optimization problems using necessary and sufficient optimality conditions for the nested problem. Then, we explore the family of so-called P-split reformulations for this single-level problem and test their applicability in a preliminary numerical study.