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The research described in this dissertation focuses on developing a process to remove oligomers and suppress their formation by intercepting the aging procedure's precursors using adsorbents when biodiesel and its blends are used as fuel. So far, there has been no attempt to cause the stabilization of biodiesel and its blends using adsorbents from open literature. This investigation is one of the first studies on the use of adsorbents to mitigate biodiesel and diesel fuel's stability behavior–biodiesel blends and the removal of oligomers or suppressing the formation of high molecular mass species in aging oil. This study's primary aim has been achieved by several experimental measurements that provided results on adsorbents' effecton fuel oxidative stability, especially ester-based fuel like biodiesel and its blends. The chemical composition and some critical rheological analyses of the samples have been measured to understand their role in the oxidation of the sample by comparing the presence and absence of the adsorbents during the aging process. Furthermore, it aims to use adsorbents to suppress oligomers' formation and remove them in aging oil due to the influence of biodiesel and its blends. The research project also seeks to stabilize fuel, especially ester-based fuel like biodiesel, and its blends using the adsorbents. The adsorbents' application will enhance biodiesel's oxidative stability and its blends during long-term storage or application, focusing on its use in plug-in hybrid vehicles, emergency power plants,and generators. The combustion engine only starts in plug-in hybrid vehicles if the battery cannot supply energy on longer journeys. As a result, the fuel remains longer in plug-in hybrid vehicles. Fuels that are exposed to heat and oxygen over anextendedperiod can form aging products. These aging products lead to the formation of deposits, especially in the case of diesel fuels mixed with biodiesel content,and can, therefore, endanger the operational safety of the vehicle in critical components such as injectors or filter units.
In dieser Masterarbeit wird die Online-Befragung von Berufsschullehrern in Hamburg als explorative Methode gewählt, um Einblicke in die aktuelle Situation an Berufsschulen zur Förderung von "Kompetenzen in der digitalen Welt" bei Auszubildenden zu Kaufleuten für Büromanagement zu erhalten. Das Hauptziel ist es, die vorhandenen Chancen und Herausforderungen bei der Förderung genannter Kompetenzen bei den Schülern zu identifizieren und zu analysieren. Diese Arbeit interessiert sich außerdem für einen umfassenden Einblick in die Praktiken, Herausforderungen und Bedarfe an der Berufsschule im Zusammenhang mit der Förderung von digitalen Kompetenzen. Dafür werden verschiedene Theorien aus der Medienpädagogik zusammengefasst und deren Relevanz für die gegenwärtige Berufliche Bildung herausgestellt. Es wird sich mit verschiedenen Einflussfaktoren der digitalen Welt auf den (Berufs-)Schulunterricht auseinandergesetzt. Des Weiteren wird die Entstehungshistorie der Kultusministerkonferenz (KMK)-Strategie "Bildung in der digitalen Welt" nachvollzogen. Damit soll die theoretische Basis zur Beantwortung der Frage gelegt werden, inwiefern "Kompetenzen in der digitalen Welt" in der Beruflichen Bildung in Hamburg gefördert werden. Diese grundsätzliche Fragestellung wird anhand von empirischen Datenmaterial hinsichtlich der Förderungsabsichten beantwortet. Gerade vor dem Hintergrund der technologischen Entwicklungen der letzten Jahrzehnte mit "Kompetenzen in der digitalen Welt" als entscheidenden Schlüsselqualifikationen möchte die vorliegende Arbeit durch die erzielten empirischen Ergebnisse zur aktuellen Diskussion über die Förderung digitaler Kompetenzen bei Auszubildenden beitragen und bietet Handlungsempfehlungen für die Praxis. Indem mit dieser Arbeit das Verständnis für die bestehenden Chancen und Herausforderungen erweitert wird, können bildungspolitische Maßnahmen entwickelt werden, um den Anforderungen der digitalen (Arbeits-)Welt gerecht zu werden.
In past digital health interventions, an issue has been that participants drop out over time which is referred to as the "law of attrition" (Eysenbach, 2005). Based on this, the study proposes that though initially, participants respond to the intervention, there is a hypothesized second diminishing effect of an intervention. However, the study suggests that on top, there is a third effect. Independent of the individual notification or nudge, people could build the knowledge, skills and practice needed to independently engage in the behavior themselves (schraefel and Hekler, 2020). Using behavioral theory and inspired by prior animal computational models of behavior, the thesis proposes a dynamical computational model to allow for a separation of intervention and internalization. It is targeted towards the specific case of the HeartSteps intervention that could not explain a diminishing immediate effect of the intervention, second hypothesized effect, while a person’s overall steps remained constant, third effect (Klasnja et al., 2019). The study incorporates a habituation mechanism from learning theory that can account for the immediate diminishing effect. At the same time, a reinforcement mechanism allows participants to internalize the message and engage in behavior independently. The simulation shows the importance of a participant’s responsiveness to the intervention and a sufficient recovery period after each notification. To estimate the model, the study uses data from the HeartSteps intervention (Klasnja et al., 2019; Liao et al., 2020), a just-in-time adaptive intervention that sent two to five walking suggestions per day. The study runs a Bayesian estimation with Stan in R. Additional validation tests are needed to estimate the accuracy of the model for different individuals. It could however serve as a template for future just-intime adaptive interventions due to its generic structure. In addition, this model is of high practical relevance as its derived dynamics can be used to improve future walking suggestions and ultimately optimize notification-based digital health interventions.
This thesis aims to contribute to a better understanding of the actual implementation of transdisciplinary research in sustainability science. Following three aims, this work likes to (1) contribute to the measurability of transdisciplinary research processes as well as their societal and academic outputs and impacts, to (2) demarcate transdisciplinary research from other modes of research in sustainability science and to (3) identify and examine the determinants that shape the contribution of transdisciplinary research to societal action for sustainable development and to scientific knowledge production. To serve these aims a mixed methods approach is applied that combines strong quantitative elements with in-depth qualitative analyses that integrate the perspectives of practitioners. This thesis provides a broad set of indicators to describe and assess transdisciplinary research that translate theoretical concepts form transdisciplinarity theory into observable variables. The indicators offer a holistic perspective on transdisciplinary research by representing research mode characteristics, societal as well as scientific outcomes of research projects and their specific context. To theoretically demarcate transdisciplinary research from other forms of research, a narrative literature review first elaborates the differences between "normal science", political use of scientific knowledge and transdisciplinarity in their underlying logics of problem definition, knowledge production and research utilization. Subsequently, these concepts were compared with perspectives and expectations of practitioners in the forest sector on integrative research settings. Moreover, a cluster analysis of data from 59 research projects identified five research modes that empirically demarcate ideal-typical transdisciplinary research from other research modes within sustainability science: (1) purely academic research, (2) practice consultation, (3) selective practitioner involvement, (4) ideal-typical transdisciplinary research and (5) practice-oriented research. Based on this finding, transdisciplinary research can be characterized as an intensive, but balanced involvement of practitioners. It incorporates not only the needs and goals of the practitioners but also their norms and values. Ideal-typical transdisciplinary research goes beyond mere consultatory research approaches and must be distinguished from what is conceptualized as applied research. Regression analysis of 81 research projects and statistical group comparisons of the five research mode clusters show that societal and academic outputs and impacts vary with specific project characteristics and combinations of project characteristics defined as research modes. The findings indicate that more interactive research modes reach more societal impacts. In particular, the involvement of practitioners in early project phases and the targeted dissemination of the research results positively affect societal impacts. This finding also aligns with practitioner expectations on integrative research and research utilization, provided by qualitative analysis. Moreover, the quantitative results show that scientific outputs and impacts decrease with the intensity of interactions, indicating a trade-off between societal and scientific outcomes and impacts. Overall, the empirical results of this thesis support the claimed effectiveness of transdisciplinary research in providing societally relevant, applicable knowledge and encourage further funding of transdisciplinary research by funding agencies.
The computational analysis and the optimization of transport and mixing processes in fluid flows are of ongoing scientific interest. Transfer operator methods are powerful tools for the study of these processes in dynamical systems. The focus in this context has been mostly on closed dynamical systems and the main applications have been geophysical flows. In this thesis, the authors consider transport and mixing in closed flow systems and in open flow systems that mimic technical mixing devices. Via transfer operator methods, They study the coherent behavior in closed example systems including a turbulent Rayleigh-Bénard convection flow and consider the finite-time mixing of two fluids. They extend the transfer operator framework to specific open flows. In particular, they study time-periodic open flow systems with constant inflow and outflow of fluid particles and consider several example systems. In this case, the transfer operator is represented by a transition matrix of a time-homogeneous absorbing Markov chain restricted to finite transient states. The chaotic saddle and its stable and unstable manifolds organize the transport processes in open systems. The authors extract these structures directly from leading eigenvectors of the transition matrix. For a constant source of two fluids in different colors, the mass distribution in the mixer and its outlet region converges to an invariant mixing pattern. In parameter studies, they quantify the degree of mixing of the resulting patterns by several mixing measures. More recently, network-based methods that construct graphs on trajectories of fluid particles have been developed to study coherent behavior in fluid flow. They use a method based on diffusion maps to extract organizing structures in open example systems directly from trajectories of fluid particles and extend this method to describe the mixing of two types of fluids.
In this chapter, we aim to present how shame, vulnerability, self-care and community care interrelate to one another and how they help build the necessary foundation for mutual care in interdependent communities, and thus for community-supported projects (CSX). Furthermore, we argue that by looking at the role of shame and vulnerability within our personal life, as we simultaneously learn to take care of ourselves, we then lay a solid foundation for learning how to support others. We then suggest that at the birthplace between healthy sustainable self-care and community care, people and communities are able to shift from a hyper-individualized lifestyle (isolation, disconnection) to a more collective community-centered approach (belonging and connection) that finally creates the perfect recipe for the creation of CSX Projects and a more inclusive and kinder economy for all.
In this framework the editor describes the intention, background and structure of the publication "Community Supported Economy - CSX - New entrepreneurial narratives in words, deeds, and pictures". In addition, this chapter introduces the readers to the concept of community-supported economy (CSX) and opens the space for their own reflection.
How can CSX be applied to different industries in the cultural field? The following three subchapters discuss general problems of the cultural sector (the past), current practice examples of CSX (the present) and visions about new possibilities in this sector (the future), envisioning the progress of the sector through the implementation of CSX as an alternative economic model. This chapter explores this by using creative writing styles. While all the characters are fictional, the characterizations and the outline of the story draw from our scientific research. Our main protagonist is Quinn who studies Cultural Studies, is a volunteer in several cultural initiatives and works at a podcast studio. Planning to be done
with the Master's program in about a year, questions about possibilities of a future employment in the cultural sector are becoming more present for Quinn and their fellow students.
The concept of CSX allows us to envision how the idea of collaborative problem-solving and non-competitive change-making could be brought to life. The participation at the CSX meets Lüneburg event fueled the vision to find out more about how the CSX framework could be transferable and applicable to the consulting industry and sustainability consulting in particular. The encouraging kick-off led to the research question of: “Can sustainability consulting better fulfill its purpose in a CSX context as opposed to the conventional way?” The aims connected to this research question were to determine the status quo of community-supported approaches in sustainability consulting and to increase the visibility of existing organisations. Goals were also to find out how community-based work can lead to fruitful results in sustainability consulting. This was ought to be done by assessing the embodiment of CSX aspects in existing examples from practice.
This chapter is structured into two sub chapters, studied and written by two research-groups, titled: (1) Tales of Challenge (2) Tales of Success. The chapter concludes with a common summary of all findings. In both sub chapters the same approach was applied. Semi-structured interviews were conducted and analyzed according to Mayring (2000) to collect perspectives from practice and research. Some interviews were conducted by each research group separately and some together. Also, a method inspired by Photovoice was used to gain a deeper understanding of specific challenges and drivers in the respective projects. Inspired by the Photovoice method (Wang and Burris, 1997), interviewees were asked to share a picture and short description answering a question posed by the researchers to gain a deeper understanding of specific challenges and drivers in the respective projects. Our shared main character, Joice, will keep popping up during this chapter to share her experience.