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Influence of volatiles (H2O and CO2) on shoshonite phase equilibria
Get PDFExperiments were performed at 500 MPa, 1080 °C and water activities (aH2O) from 0.0 to 1.0, in fluid-present and fluid-absent conditions, with the aim of constraining the effect of volatiles on phase equilibrium assemblages of a shoshonite from Vulcanello (Aeolian Islands, Italy). Experiments were run both under reducing and oxidizing conditions and results show that proportions, shapes and size of crystals vary as a function of the volatile composition (XH2O and XCO2) and volatile content. Clinopyroxene (Cpx) is the main crystallising phase and is compositionally analogous to Cpx crystals found in the natural rock. Plagioclase (Pl) is stable only for water activity lower than 0.1, whereas Fe–Ti oxides are present in all experimental runs, except for those where log fO2 was lower than −9, (∆NNO −0.11) irrespective of the presence of CO2. The addition of CO2 (2.8 wt%) in nominally dry experimental charges substantially reduces the crystallinity by ca. 1/3 compared to volatile free experiments. This result has important consequences upon the physical properties of the magma because it influences its viscosity and, as a consequence, velocity during its travel to the Earth surface. Assuming that the widths of Vulcanello conduits vary from 0.5 to 1.5 m, estimates of the ascent velocity vary in the range 1.5 × 10−4–3.5 × 10−2 m·s−1 for CO2 free systems and from 5.7 × 10−4–1.3 × 10−1 m·s−1 for CO2 bearing systems. Since shoshonitic magmas are common not only in the Italian volcanic provinces (Aeolian Arc, Campi Flegrei, Ischia Island, Pontine Islands, Monti Cimini, Monte Amiata, Capraia Island, Radicofani, Roccamonfina) but also in different volcanoes worldwide (Yellowstone, Mariana Arc, Kurile Arc, Tonga Arc, Andean Arc, Kamchatka Arc), we suggest that the new data will be useful to better understand shoshonitic magma behaviour under relevant geological scenarios. As such, we also suggest that hazard evaluation should incorporate the probability of very rapid ascent of poorly-evolved melts from depth
Identification Of Interdependencies In Socio-Technical Information Systems In Manufacturing Companies For Greater Adaptability
Get PDFDuring the selection and implementation of complex (manufacturing related) IT systems, such as ERP or MES, organizations often mainly focus on meeting current requirements. However, to ensure that these IT systems can also accommodate future, unforeseen requirements, it is essential to design and implement IT systems that are adaptable to change. The adaptability of IT systems is influenced not only by technical but also by human and organizational factors. Furthermore, companies are rarely isolated in their efforts: they often depend on external IT system vendors, introducing additional external forces into the dynamic. This creates a socio-technical information system composed of the implementing organization, an IT vendor, and the IT system itself, each with a variety of underlying elements. Any change in one of these elements can trigger changes in the others, highlighting the importance of understanding the interdependencies among them. Currently, there is no comprehensive framework that outlines these interdependencies, and in practice, potential conflicts are often identified only through the experiences of individual employees or consultants. This paper presents a model that maps the interdependencies between these elements, enabling the identification of both leading and dependent elements. Such model can support strategic planning and risk management in the implementation of new as well as adapting existing IT systems. Future research could explore linking of specific change drivers to these elements, thereby enhancing the understanding of the adaptability of socio-technical information systems in manufacturing companies as a whole
Blueprint for a New Standard - Product Specific Technical Documentation For Open Source Hardware
Get PDFThe reorganisation of value creation structures requires a comprehensive view of all stages of value creation, from the initial idea and development to the use by customers and the end of the product's life. In traditional concepts, a focal company usually drives development and physical production. Open Source Hardware (OSH) offers an alternative approach that has been gaining popularity for years and can contribute to the transformation to a more sustainable production ecosystem. The fair compensation of developers and the free participation of individuals enable the collaborative creation of new value and innovation through the publication of design information. With the increasing number of sources for downloading OSH and the general growing number of designs, a first attempt to develop a standard for OSH was made in 2020 with DIN SPEC 3105. However, significant issues remain with the qualitative technical documentation necessary for the production of OSH in industrially organized units, as the standard only establishes very general documentation requirements. The Product Life Cycle (PLC) according to DIN ISO 15226 provides a globally accepted basis for the organization of technical documentation in the context of the product development process. Based on this model, numerous standards and guidelines are identified and systematically analysed in this research in order to identify objects of technical documentation. These are assigned to the Product Life Cycle (PLC) and linked with existing specialist knowledge to derive a system for the product-specific selection of suitable objects for OSH technical documentation
Entrepreneurship und Social Impact : Forschungsprojekte der Area Strategic Management
Get PDFUm die globalen Herausforderungen wie Klimawandel, Umweltverschmutzung, Verlust von Biodiversität, Armut und Unterversorgung, bewältigen zu können, sind neue Formen des Wirtschaftens und der Zusammenarbeit notwendig. Entrepreneure und Startups nehmen in diesem Prozess eine Vorreiterrolle ein. Dieser Beitrag stellt aktuelle Forschungsprojekte der Area Strategic Management an der Wirtschaftswissenschaftlichen Fakultät aus dem Bereich Entrepreneurship und Social Impact vor
Method For Quantifying The Strategic Value Contribution Of Start-up Investments By Established Companies
Get PDFInvesting in start-ups is a promising source of innovation for established companies. They enable significantly faster access to new technologies, markets and business model innovations compared to internal innovation activities. Various quantitative and qualitative valuation methods already exist for estimating the financial return potential of a start-up investment. However, when established companies invest in start-ups, the focus is usually on strategic returns, in terms of value contribution to the corporate goals of the company. Due to the diversity of the various objectives and the limited information base for an investment, quantifying the potential value contribution represents a major challenge for the investing companies. Therefore, they usually reduce the evaluation to a qualitative assessment of the strategic fit, which limits informed decisions. This paper provides an application-oriented method for quantifying the strategic value contribution of a start-up investment for the investing company. This is a significant contribution to decision support prior to upcoming start-up investments. First, the theoretical background is briefly introduced, existing approaches are reviewed and their deficits are discussed, before model requirements are identified and the methodology and its sub-models are derived
Integration of Base Excitation with nonlinear Coupling within the Multiharmonic Balance Method
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Goal-oriented error control for space-time reduced-order modeling using incremental proper orthogonal decomposition
Get PDFIn this thesis, we explore goal-oriented model order reduction to efficiently solve time-dependent partial differential equations. We introduce a novel, online-adaptive reduced-order modeling approach called MORe DWR (Model Order Reduction with Dual-Weighted Residual error estimates), which combines space-time model order reduction with dual-weighted residual-based error control and on-the-fly basis enrichment through incremental proper orthogonal decomposition. The adaption of the reduced-order model is based on the rational to use local error indicators extracted from the dual-weighted residual error estimates to refine the model. In an iterative process, the error in a goal functional is estimated during the simulation, allowing the reduced basis to be incrementally updated with new high-fidelity snapshots if the estimate exceeds a given threshold. This enables adaptive enrichment of the reduced basis in response to unanticipated changes in the solution behavior. As a result, there is no need for an expensive offline phase to explore the solution manifold, as the MORe DWR method automatically switches between reduced-order and full-order computation as needed. This method reduces the total number of full-order model solves compared to classical reduced-order modeling, provides robust estimation of the quantity of interest, and generates well-suited reduced basis spaces for the problem at hand. We test our novel approach on heat and elastodynamics problems and subsequently extend it to poroelasticity. Finally, we apply the MORe DWR framework to time-dependent and parametrized partial differential equations, where it is used for efficient exploration of the solution manifold
Freiheit zu welchem Zweck? : Aufklärungs- und Fortschrittskritik in Rousseaus Abhandlung über den Ursprung und die Grundlagen der Ungleichheit unter den Menschen (1755)
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Diet quality, nutritional status, and cardiovascular risk factors in a flexitarian cohort
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Background and aim: The popularity of plant-based dietary patterns has been steadily increasing in Western societies, and a growing number of people are adopting a meat-reduced, flexitarian diet. Although vegetarian and vegan diets have been extensively studied, the research on flexitarian diets is still limited. Furthermore, there is no universally accepted definition of flexitarianism, and various studies use different criteria for defining and measuring this dietary pattern. As a result, the current knowledge is incomplete so far. There is a lack of information, for example, regarding the dietary quality of flexitarians (FXs), including the use of plant-based meat alternatives. In addition, there is still not enough data on whether reducing meat and meat product intake is sufficient to achieve an adequate nutritional status and cardiovascular health benefits. Therefore, the objectives of this thesis are to investigate the diet quality (measured by a newly developed Healthy Eating Index – flexible: HEI-flex), nutritional intake, endogenous blood biomarker status, and cardiovascular risk parameters of FXs compared to vegans (Vs) and omnivores (OMNs).
Methods: Ninety-four healthy male and female participants aged between 25 and 45 years, with a body mass index between 20 and 28 kg/m2 and non-smokers were enrolled in a cross-sectional study. They were classified into three dietary groups based on their long-term dietary habits of ≥ one year: 32 FXs, 33 Vs, and 29 OMNs. The FXs followed a plant-based diet with the occasional consumption of meat and meat products of ≤ 50 g/d, while the Vs abstained from all animal-based foods. The OMNs consumed a mixed diet, with regular consumption of meat and meat products of ≥ 170 g/d. The participants were matched for both age and sex within each group and across the three groups. A food frequency questionnaire and a health-related activities questionnaire were filled out on the examination day. Fasting blood samples were taken to determine the levels of vitamin B12 and its status markers, vitamin D, iron, iodine, and folic acid, as well as zinc, magnesium, and calcium. Additionally, blood lipids, glucose metabolism parameters, and selected inflammatory markers were analysed. Anthropometric data and bioelectrical impedance analysis (BIA) were performed to determine the body composition of each participant. Moreover, vascular parameters, including pulse wave velocity (PWV), were measured. Nutrient intakes were recorded via three-day food records prior to the study visit.
Results: The study results reveal that the nutritional intake of FXs, Vs, and OMNs was adequate overall. However, critical nutrients, such as vitamin D, vitamin B12, iodine, and iron status markers, were observed for FXs, which are also known to be critical in an exclusively plant-based (vegan) diet. Additionally, the study also unveils differences in the diet quality among the three groups, with Vs having the most favourable food choices, followed by FXs and OMNs with less favourable results. Regarding cardiovascular risk parameters, benefits were observed for FXs in blood lipid parameters compared to OMNs. The flexitarian participants reached the most favourable results across all groups for the severity of metabolic syndrome (MetS) and also in PWV.
Conclusion: A plant-based, meat-reduced flexitarian diet offers benefits in terms of diet quality and cardiovascular risk factors compared to an omnivore diet. However, the nutritional status showed that there were partially critical nutrients which are already known in an exclusively plant-based, vegan diet. In sum, a flexitarian diet represents a beneficial alternative to an omnivore diet. However, further long-term studies with clearly defined flexitarian cohorts are necessary to verify the results of the present study.Hintergrund und Ziel: Pflanzlich-basierte Ernährungsformen werden in der westlichen Industriegesellschaft zunehmend beliebter, und immer mehr Menschen entscheiden sich für eine fleischreduzierte, flexitarische Ernährungsweise. Während vegetarische und vegane Kostformen gut erforscht sind, ist jedoch die Forschungslage zur flexitarischen Ernährung noch begrenzt. Zudem gibt es keine allgemein anerkannte Definition des Flexitarismus, und verschiedene Studien verwenden unterschiedliche Kriterien zur Definition und Erfassung dieser Ernährungsform. Infolgedessen ist das derzeitige Wissen noch lückenhaft. Beispielsweise fehlen Informationen über die Qualität der Ernährung von Flexitariern, einschließlich der Verwendung von Fleischalternativen auf pflanzlicher Basis. Außerdem gibt es nur wenige Daten darüber, ob eine Reduzierung des Verzehrs von Fleisch und Fleischprodukten ausreicht, um einen angemessenen Nährstoffstatus zu erreichen und Vorteile für die kardiovaskuläre Gesundheit zu erzielen. Ziel dieser Arbeit ist es daher, die Ernährungsqualität (gemessen mit dem neu entwickelten Healthy Eating Index - flexible, HEIflex), die Nährstoffzufuhr, den Status endogener Biomarker im Blut und kardiovaskuläre Risikoparameter von Flexitariern im Vergleich zu Veganern und Omnivoren zu untersuchen. Methodik: In einer Querschnittsstudie wurden 94 gesunde Männer und Frauen (Nichtraucher) im Alter von 25 bis 45 Jahren mit einem BMI von 20 bis 28 kg/m² untersucht. Basierend auf ihren langfristigen Ernährungsgewohnheiten (≥ 1 Jahr) wurden sie in drei Gruppen eingeteilt: 32 Flexitarier (FXs), 33 Veganer (Vs) und 29 Omnivore (OMNs). FXs ernährten sich überwiegend pflanzlich mit gelegentlichem Konsum von Fleisch und Fleischprodukten von ≤50 g/Tag, während Vs auf alle tierischen Lebensmittel verzichteten. OMNs konsumierten regelmäßig Fleisch und Fleischprodukte (≥170 g/Tag). Die Teilnehmer der drei Gruppen waren hinsichtlich Alter und Geschlecht vergleichbar. Am Untersuchungstag wurden Fragebögen zu Lebensmittelzufuhr und gesundheitsbezogenen Aktivitäten ausgefüllt und Nüchternblutproben entnommen, um die Konzentrationen von Vitamin B12 und seiner Statusmarker, Vitamin D, Parameter des Eisenstatus, Jod, Folsäure, Zink, Magnesium und Kalzium sowie Blutfette, Glukosestoffwechselparameter und weitere Entzündungsmarker zu analysieren. Zur Bestimmung der Körperzusammensetzung wurden anthropometrische Messungen und eine bioelektrische Impedanzanalyse (BIA) durchgeführt. Zusätzlich wurden vaskuläre Parameter, einschließlich der Pulswellengeschwindigkeit (PWV), gemessen. Die Nährstoffzufuhr wurde mittels dreitägiger Ernährungsprotokolle im Vorfeld des Studientags erfasst. Ergebnisse: Die Ergebnisse der Studie zeigen, dass die Nährstoffzufuhr von allen drei Ernährungsformen (FXs, Vs und OMNs) insgesamt ausreichend war. Allerdings wurden bei den FXs kritische Werte bei Vitamin D, Vitamin B12, Jod und Eisenstatusmarkern beobachtet, die auch bei einer rein pflanzlichen (veganen) Ernährung als kritisch gelten. Darüber hinaus zeigte die Studie auch Unterschiede in der Ernährungsqualität zwischen den drei Gruppen, wobei die Vs die günstigste Lebensmittelauswahl hatten, gefolgt von den FXs und den OMNs
mit weniger günstigen Ergebnissen. Hinsichtlich der kardiovaskulären Risikoparameter
wurden bei den FXs im Vergleich zu den OMNs Vorteile bei den Blutfettwerten festgestellt. Beim Schweregrad des Metabolischen Syndroms (MetS) und auch bei der PWV schnitten die FXs von allen drei Gruppen am vorteilhaftesten ab. Schlussfolgerung: Eine pflanzenbasierte, fleischreduzierte flexitarische Ernährungsweise bietet im Vergleich zu einer omnivoren Kost Vorteile hinsichtlich der Ernährungsqualität und
kardiovaskulärer Risikofaktoren. Die Untersuchung des Ernährungsstatus zeigte jedoch, dass es bei vielen FXs kritische Nährstoffe gibt, die ebenfalls bei einer rein pflanzlichen, veganen Ernährung als potentiell kritisch bekannt sind. Zusammenfassend lässt sich sagen, dass eine flexitarische Ernährungsform eine vorteilhafte Alternative zu einer omnivoren Ernährung darstellt. Allerdings sind weitere Langzeitstudien mit klar definierten Flexitarier-Kohorten notwendig, um die Ergebnisse der vorliegenden Studie zu untermauern. Studienregistrierung: Deutsches Register Klinischer Studien DRKS0001988
Conceptual Design and Dynamic Modeling of Large-Scale Hydrogen Energy Storage Systems
Get PDFWith the growing demand for sustainable and renewable energy sources, the need for efficient and reliable energy storage solutions becomes increasingly crucial. Due to their high achievable energy capacities in the range of GWh, hydrogen energy storage systems (HESS) present a promising option for addressing the intermittency and variability of renewable energy generation. The thesis at hand helps to develop a comprehensive understanding of the operational behavior of such systems.
First, a conceptual design is developed since no HESS is currently under operation and it is not possible to refer to real-world data. Thereby, the current state of the art of the individual components and existing design concepts from the literature are taken into account. Next, this thesis proposes a flexible system model to gain insights into the operating behavior of the designed system at nominal and off-design conditions.
This model comprises a proton-exchange membrane (PEM) electrolysis system, a compression line, an underground salt cavern, a PEM fuel cell system, and further balance of plant components (BOP) such as transformers or heat exchangers.
The model’s results show that the system’s behavior changes substantially during partial loads due to the varying performance of the individual components. While the BOP components like transformers and compressors are of minor relevance to the overall performance at nominal loads, they become increasingly relevant at lower part-loads both during the charging and discharging phase. Reducing the load compared to the nominal load first leads to an increase in efficiency due to decreasing losses in the electrolysis and fuel cell systems. However, because of the increasing BOP losses, the efficiency drops again at low relative loads after reaching their maximum of 68.24% during the charging phase and 54.20% during the discharging phases. At nominal load, a round-trip efficiency of 28.05% was obtained. In addition to this evaluation of the system’s operational behavior, possible improvements regarding the system design are proposed and discussed, thereby facilitating the modular character of the built model.
Overall, the thesis at hand provides a conceptual design and the first in-depth model of a HESS, which is characterized by its flexibility and modular design. This model can be utilized for further research like a techno-economic analysis or to optimize the overall system by evaluating different configuration possibilities