Publikationen

2021

• Software-in-the-Loop Simulation of a Gas-Engine for the Design and Testing of a Wind Turbine Emulator

  Rohr, A., & Jauch, C. (2021). Software-in-the-Loop Simulation of a Gas-Engine for the Design and Testing of a Wind Turbine Emulator. Energies, 14. http://doi.org/10.3390/en14102898

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  In order to investigate the grid integration of wind turbines (WT) of various scales and designs, a wind turbine emulator (WTE) is being built in Flensburg within the state-funded project GrinSH. The special feature of this WTE is the use of a large gas engine instead of an electric motor to emulate the behavior of a WT. In order to develop the controls of this innovative WTE and to design the upcoming test runs under safe conditions, a software in the loop model (SILM) was applied. This SILM contained a mathematical model of the wind turbine, mathematical models of the gas engine with an integrated controller, and a model of the generator and frequency converter unit, as well as a preventive modulator of the reference signal (PMRS). The PMRS module converts the reference signal of the emulated WT in such a way that the dynamics of the engine components can be calculated and balanced in advance to enable the required behavior of the entire SILM despite the dynamics of the gas engine. It was found that the PMRS module, developed and tested in this work, increased the ability of the WTE, based on a gas engine, to reproduce the dynamics of a WT.

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    • Rohr, Alexander
    • Jauch, Clemens

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  • 2021
  • Journal Article
  • • Alexander Rohr
    • Prof. Dr. Clemens Jauch

• Capturing shrinkage and neck growth with phase field simulations of the solid state sintering.

  Ivannikov, V., Thomsen, F., Ebel, T., & Willumeit-Römer, R. (2021). Capturing shrinkage and neck growth with phase field simulations of the solid state sintering. Modelling and Simulation in Materials Science and Engineering, 29(7). http://doi.org/10.1088/1361-651X/ac1f87

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    • Thomsen, Fritz

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  • 2021
  • Journal Article
  • • Vladimir Ivannikov
    • Fritz Thomsen
    • Thomas Ebel
    • Regine Willumeit-Römer

• Automizing the manual link in maritime supply chains? An analysis of twistlock handling automation in container terminals

  Kugler, M., Brandenburg, M., & Limant, S. (2021). Automizing the manual link in maritime supply chains? An analysis of twistlock handling automation in container terminals. Maritime Transport Research, 2, 100017. http://doi.org/https://doi.org/10.1016/j.martra.2021.100017

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  The study at hand elaborates on potential barriers, prerequisites and optimization potentials for the automation of the twistlock handling process in container terminals. A case analysis enlightens latest automation developments of this essential task in container transport. Eight experts from different organizations in maritime logistics and seaport operations were interviewed in a qualitative multiple-case research design. The interviews were evaluated by qualitative-quantitative content analysis with MAXQDA software. Automated twistlock handling systems are hardly implemented, although they represent the missing link between other container handling technology in the automated container transport. The study reveals that most implementation barriers consist of technological issues, followed by economic and strategic barriers. The study identifies implementation strategies and their key success and shows that safety improvements and cost reductions are major benefits of this automation. An innovation framework for this field of automation is conceptualized as scientific contribution. Practical implications include recommendations for relevant stakeholders in container logistics.

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    • Brandenburg, Marcus

  • Fachbereich

    • Fachbereich 4: Wirtschaft
    • Fachbereich 1: Maschinenbau, Verfahrenstechnik und Maritime Technologien

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  • 2021
  • Journal Article
  • • Michael Kugler
    • Marcus Brandenburg
    • Sander Limant
  • • Container logistics
    • Maritime logistics
    • Process automation
    • Twistlock handling
    • case study
    • Expert interviews

• Grid Services and Stress Reduction with a Flywheel in the Rotor of a Wind Turbine

  Jauch, C. (2021). Grid Services and Stress Reduction with a Flywheel in the Rotor of a Wind Turbine. Energies, 14. http://doi.org/10.3390/en14092556

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  Wind power penetration increases in most grids and the sizes of wind turbines increase. This leads to increasingly tough requirements, which are imposed on wind turbines, both from the grid as well as from economics. Some of these partially contradictory requirements can only be satisfied with additional control mechanisms in the wind turbines. In this paper, such a mechanism, i.e., a hydraulic–pneumatic flywheel system in the rotor of a wind turbine, is discussed. This flywheel system supports a wind turbine in providing grid services such as steadying the power infeed, fast frequency response, continuous inertia provision, power system stabilization, and low voltage ride-through. In addition, it can help mitigate the stress on the mechanical structure of a wind turbine, which results from varying operating points, imbalances in the rotor, gravitation that acts on the blades, in-plane vibrations, and emergency braking. The study presented in this paper is based on simulations of a publicly available reference wind turbine. Both the rotor blade design as well as the design of the flywheel system are as previously published. It is discussed how the aforementioned grid services and the stress reduction mechanisms can be combined. Finally, it is concluded that such a flywheel system broadens the range of control mechanisms of a wind turbine substantially, which is beneficial for the grid as well as for the wind turbine itself.

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    • Jauch, Clemens

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    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Prof. Dr. Clemens Jauch

• Financial performance and firm efficiency of automotive manufacturers and their suppliers A longitudinal data envelopment analysis

  Brandenburg, M., & Hahn, G. J. (2021). Financial performance and firm efficiency of automotive manufacturers and their suppliers A longitudinal data envelopment analysis. Logistics Research, 14(1), 26. http://doi.org/10.23773/2021_01

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  A data envelopment analysis (DEA) is presented to assess evolutions of firm efficiency and financial performance in automotive supply chains. A sample of 32 decision-making units (DMUs), 17 globally operating original equipment manufacturers (OEMs) and 15 key suppliers from the automotive industry, is in focus of this analysis in which cost levels and capital requirements are put into relation to sales growth and profit. Cost of goods sold, operating capital, and net fixed assets represent the financial input of a company while sales growth and earnings before interest and taxes (EBIT) reflect the financial output. The financial performance of a firm is indicated by its efficiency, calculated by an input-oriented variable returns to scale model. A multiple linear regression analysis reveals which operational performance factors are predictors of financial performance. A longitudinal DEA approach that covers the years from 2003 to 2017 is chosen to reveal performance evolutions over time. In order to analyze the stability of relationships between efficient firms (peers) and inefficient ones (followers) over time, changes in the performance relationship network are assessed in a graph-theoretic approach. In this study, geographical and structural specifics of DMU groups are taken into account. The study reveals similarities and differences between OEMs and their suppliers regarding the importance of value drivers and detects periods of performance losses and recovery from the global economic crisis.

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    • Brandenburg, Marcus

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  • 2021
  • Journal Article
  • • Marcus Brandenburg
    • Gerd Hahn
  • • Automotive industry
    • Data Envelopment Analysis
    • Financial performance
    • Supply networks

• Arbeiten Frauen aufgrund des Ehegattensplittings weniger? — Eine empirische Untersuchung für Deutschland

  Chirvi, M. (2021). Arbeiten Frauen aufgrund des Ehegattensplittings weniger? — Eine empirische Untersuchung für Deutschland. Steuer und Wirtschaft, 98(2). http://doi.org/10.9785/stuw-2021-980207

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  Der Beitrag soll zur Klärung der Frage beitragen, ob das Ehegattensplitting, wie vielfach behauptet wird, einen negativen Einfluss auf das Arbeitsverhalten verheirateter Frauen hat. Hierzu kommt für Deutschland erstmals ein von Quasi-Experimenten inspirierter Ansatz zum Einsatz, bei dem anhand des allgemeinen Effekts der Heirat auf das Erwerbsverhalten der heiratenden Frauen die Wirkung des Ehegattensplittings geschätzt wird. Die Veränderung des Arbeitsverhaltens heiratender Frauen wird dabei der Veränderung bei jenen Frauen gegenübergestellt, die im gleichen Zeitraum weiterhin mit ihrem festen Partner zusammenleben, ohne zu heiraten (Kontrollgruppe). Die Ergebnisse sprechen eindeutig gegen einen unmittelbaren negativen Effekt des Ehegattensplittings auf das Erwerbsverhalten von Frauen. Jedoch reduzieren heiratende und zeitgleich ein Kind bekommende Frauen ihre Erwerbstätigkeit stärker als gebärende Frauen in der Kontrollgruppe. In Folge einer lediglich teilweisen Abschaffung des Ehegattensplittings, die in den Entwürfen zu Parteiprogrammen zur Bundestagswahl 2021 teilweise gefordert wird, sind sogar noch geringere Effekte auf das Arbeitsverhalten zu erwarten.

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    • Chirvi, Malte

  • Fachbereich

    • Fachbereich 4: Wirtschaft

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  • 2021
  • Journal Article
  • • Malte Chirvi

• \# Covid-19: An Exploratory Investigation of Hashtag Usage on Twitter

  Petersen, K., & Gerken, J. M. (2021). \# Covid-19: An Exploratory Investigation of Hashtag Usage on Twitter. Health Policy.

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    • Petersen, Kai
    • Gerken, Jan

  • Abteilung/Einrichtung

    • FLAIR - Flensburg Artificial Intelligence Research

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  • 2021
  • Journal Article
  • • Kai Petersen
    • Jan Gerken

• Marine microbial-derived molecules and their potential medical and cosmetic applications )

  Zhang, J., Zeng, R., & Labes, A. (2021). Marine microbial-derived molecules and their potential medical and cosmetic applications ). Frontiers in Microbiology, 12, 1965. http://doi.org/10.3389/FMICB.2021.706152

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  • 2021
  • Journal Article
  • • J. Zhang
    • R. Zeng
    • Antje Labes

• Coupled power plant and geostorage simulations of porous media compressed air energy storage (PM-CAES)

  Pfeiffer, W. T., Witte, F., Tuschy, I., & Bauer, S. (2021). Coupled power plant and geostorage simulations of porous media compressed air energy storage (PM-CAES). Energy Conversion and Management, 249, 114849. http://doi.org/https://doi.org/10.1016/j.enconman.2021.114849

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  Porous media compressed air energy storage (PM-CAES) systems that use porous geological formations such as sandstone may provide large storage capacities in future energy systems based primarily on fluctuating renewable energy sources. In CAES systems, the instantaneous power and stored energy are closely linked to the storage pressure and the mass flow rate achievable in the geological reservoir. Therefore, a coupled simulator that accurately represents the power plant, the geostorage site, and their interactions during all potential PM-CAES system operation modes is presented in this paper. Using adiabatic and diabatic power plant topology test designs, strong feedback between the achievable storage rates and capacities of the chosen power plant design and geostorage site are found, thus confirming the benefit of this integrated modelling approach. Using a generic, highly cyclic load profile for daily peak shaving with charging and discharging rates of 100 MW and an adiabatic power plant topology, it is found that all discharging targets can be met but the achievable charging rates decrease to approximately 95 MW due to increased pressure in the geostorage after approximately 10 cycles. When a diabatic power plant design is considered, a long-term decrease in the geostorage pressure is found. Correspondingly, the charging power always meets the specifications, while the discharging power decreases slowly from the 20th storage cycle onwards to 79 MW in the 31st cycle. The newly developed simulation tool thus allows one to predict achievable power rates and geostorage pressures for PM-CAES systems, enabling the identification of efficient PM-CAES designs.

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  • Personenseiten

    • Witte, Francesco
    • Tuschy, Ilja

  • Profilbereich

    • Erneuerbare Energien und nachhaltige Entwicklung

  • Forschungsfeld

    • Wärme
    • Netzintegration

  • Fachbereich

    • Fachbereich 2: Energy and Life Science

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  • 2021
  • Journal Article
  • • Wolf Pfeiffer
    • Francesco Witte
    • Ilja Tuschy
    • Sebastian Bauer
  • • PM-CAES
    • Compressed air energy storage
    • Geological storage
    • Coupled simulations

• Adapting Behavior Driven Development (BDD) for large-scale software systems

  Irshad, M., Britto, R., & Petersen, K. (2021). Adapting Behavior Driven Development (BDD) for large-scale software systems. Journal of Systems and Software, 177, 110944.

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    • Petersen, Kai

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    • FLAIR - Flensburg Artificial Intelligence Research

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  • 2021
  • Journal Article
  • • Mohsin Irshad
    • Ricardo Britto
    • Kai Petersen