@incollection{DachwaldBoehnhardtBrojetal.2014, author = {Dachwald, Bernd and Boehnhardt, Herrmann and Broj, Ulrich and Geppert, Ulrich R. M. E. and Grundmann, Jan-Thimo and Seboldt, Wolfgang and Seefeldt, Patric and Spietz, Peter and Johnson, Les and K{\"u}hrt, Ekkehard and Mottola, Stefano and Macdonald, Malcolm and McInnes, Colin R. and Vasile, Massimiliano and Reinhard, Ruedeger}, title = {Gossamer roadmap technology reference study for a multiple NEO Rendezvous Mission}, series = {Advances in solar sailing}, booktitle = {Advances in solar sailing}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-642-34906-5 (Print) ; 978-3-642-34907-2 (E-Book)}, pages = {211 -- 226}, year = {2014}, abstract = {A technology reference study for a multiple near-Earth object (NEO) rendezvous mission with solar sailcraft is currently carried out by the authors of this paper. The investigated mission builds on previous concepts, but adopts a strong micro-spacecraft philosophy based on the DLR/ESA Gossamer technology. The main scientific objective of the mission is to explore the diversity of NEOs. After direct interplanetary insertion, the solar sailcraft should—within less than 10 years—rendezvous three NEOs that are not only scientifically interesting, but also from the point of human spaceight and planetary defense. In this paper, the objectives of the study are outlined and a preliminary potential mission profile is presented.}, language = {en} } @inproceedings{BurgethKleefeldZhangetal.2022, author = {Burgeth, Bernhard and Kleefeld, Andreas and Zhang, Eugene and Zhang, Yue}, title = {Towards Topological Analysis of Non-symmetric Tensor Fields via Complexification}, series = {Discrete Geometry and Mathematical Morphology}, booktitle = {Discrete Geometry and Mathematical Morphology}, editor = {Baudrier, {\´E}tienne and Naegel, Beno{\^i}t and Kr{\"a}henb{\"u}hl, Adrien and Tajine, Mohamed}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-19897-7}, doi = {10.1007/978-3-031-19897-7_5}, pages = {48 -- 59}, year = {2022}, abstract = {Fields of asymmetric tensors play an important role in many applications such as medical imaging (diffusion tensor magnetic resonance imaging), physics, and civil engineering (for example Cauchy-Green-deformation tensor, strain tensor with local rotations, etc.). However, such asymmetric tensors are usually symmetrized and then further processed. Using this procedure results in a loss of information. A new method for the processing of asymmetric tensor fields is proposed restricting our attention to tensors of second-order given by a 2x2 array or matrix with real entries. This is achieved by a transformation resulting in Hermitian matrices that have an eigendecomposition similar to symmetric matrices. With this new idea numerical results for real-world data arising from a deformation of an object by external forces are given. It is shown that the asymmetric part indeed contains valuable information.}, language = {en} } @incollection{BraunBouckeBallmann2005, author = {Braun, Carsten and Boucke, Alexander and Ballmann, Josef}, title = {Numerical study of the influence of dynamic pressure and deflected ailerons on the deformation of a high speed wing model}, series = {High performance computing in science and engineering '04. Transactions of the High Performance Computing Center Stuttgart (HLRS) 2004 / Eds.: Egon Krause ...}, booktitle = {High performance computing in science and engineering '04. Transactions of the High Performance Computing Center Stuttgart (HLRS) 2004 / Eds.: Egon Krause ...}, publisher = {Springer}, address = {Berlin}, isbn = {3-540-22943-4}, pages = {225 -- 236}, year = {2005}, language = {en} } @incollection{NiemuellerEwertReuteretal.2014, author = {Niem{\"u}ller, Tim and Ewert, Daniel and Reuter, Sebastian and Ferrein, Alexander and Jeschke, Sabina and Lakemeyer, Gerhard}, title = {RoboCup logistics league sponsored by festo: A competitive factory automation testbed}, series = {RoboCup 2013: Robot World Cup XVII : Eindhoven; Netherlands; 1 July 2013 through 1 July 2013. (Lecture notes in computer science ; 8371)}, booktitle = {RoboCup 2013: Robot World Cup XVII : Eindhoven; Netherlands; 1 July 2013 through 1 July 2013. (Lecture notes in computer science ; 8371)}, publisher = {Springer}, address = {Berlin}, organization = {RoboCup International Symposium <17, 2013, Eindhoven>}, isbn = {978-3-662-44467-2 (Print) 978-3-662-44468-9 (Online)}, pages = {336 -- 347}, year = {2014}, abstract = {A new trend in automation is to deploy so-called cyber-physical systems (CPS) which combine computation with physical processes. The novel RoboCup Logistics League Sponsored by Festo (LLSF) aims at such CPS logistic scenarios in an automation setting. A team of robots has to produce products from a number of semi-finished products which they have to machine during the game. Different production plans are possible and the robots need to recycle scrap byproducts. This way, the LLSF is a very interesting league offering a number of challenging research questions for planning, coordination, or communication in an application-driven scenario. In this paper, we outline the objectives of the LLSF and present steps for developing the league further towards a benchmark for logistics scenarios for CPS. As a major milestone we present the new automated referee system which helps in governing the game play as well as keeping track of the scored points in a very complex factory scenario.}, language = {en} } @incollection{TranStaat2014, author = {Tran, Thanh Ngoc and Staat, Manfred}, title = {Shakedown analysis of Reissner-Mindlin plates using the edge-based smoothed finite element method}, series = {Direct methods for limit states in structures and materials / Dieter Weichert ; Alan Ponter, ed.}, booktitle = {Direct methods for limit states in structures and materials / Dieter Weichert ; Alan Ponter, ed.}, publisher = {Springer}, address = {Dordrecht [u.a.]}, isbn = {978-94-007-6826-0 (Print) 978-94-007-6827-7 (Online)}, doi = {10.1007/978-94-007-6827-7_5}, pages = {101 -- 117}, year = {2014}, abstract = {This paper concerns the development of a primal-dual algorithm for limit and shakedown analysis of Reissner-Mindlin plates made of von Mises material. At each optimization iteration, the lower bound of the shakedown load multiplier is calculated simultaneously with the upper bound using the duality theory. An edge-based smoothed finite element method (ES-FEM) combined with the discrete shear gap (DSG) technique is used to improve the accuracy of the solutions and to avoid the transverse shear locking behaviour. The method not only possesses all inherent features of convergence and accuracy from ES-FEM, but also ensures that the total number of variables in the optimization problem is kept to a minimum compared with the standard finite element formulation. Numerical examples are presented to demonstrate the effectiveness of the present method.}, language = {en} } @article{GoettenFingerHavermannetal.2021, author = {G{\"o}tten, Falk and Finger, Felix and Havermann, Marc and Braun, Carsten and Marino, M. and Bil, C.}, title = {Full configuration drag estimation of short-to-medium range fixed-wing UAVs and its impact on initial sizing optimization}, series = {CEAS Aeronautical Journal}, volume = {12}, journal = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Berlin}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-021-00522-w}, pages = {589 -- 603}, year = {2021}, abstract = {The paper presents the derivation of a new equivalent skin friction coefficient for estimating the parasitic drag of short-to-medium range fixed-wing unmanned aircraft. The new coefficient is derived from an aerodynamic analysis of ten different unmanned aircraft used for surveillance, reconnaissance, and search and rescue missions. The aircraft is simulated using a validated unsteady Reynolds-averaged Navier Stokes approach. The UAV's parasitic drag is significantly influenced by the presence of miscellaneous components like fixed landing gears or electro-optical sensor turrets. These components are responsible for almost half of an unmanned aircraft's total parasitic drag. The new equivalent skin friction coefficient accounts for these effects and is significantly higher compared to other aircraft categories. It is used to initially size an unmanned aircraft for a typical reconnaissance mission. The improved parasitic drag estimation yields a much heavier unmanned aircraft when compared to the sizing results using available drag data of manned aircraft.}, language = {en} } @inproceedings{GoettenFingerHavermannetal.2020, author = {G{\"o}tten, Falk and Finger, Felix and Havermann, Marc and Braun, Carsten and Marino, Matthew and Bil, Cees}, title = {Full Configuration Drag Estimation of Small-to-Medium Range UAVs and its Impact on Initial Sizing Optimization}, series = {CEAS Aeronautical Journal}, volume = {12}, booktitle = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Wien}, issn = {1869-5590}, doi = {10.1007/s13272-021-00522-w}, pages = {589 -- 603}, year = {2020}, abstract = {The paper presents the derivation of a new equivalent skin friction coefficient for estimating the parasitic drag of short-to-medium range fixed-wing unmanned aircraft. The new coefficient is derived from an aerodynamic analysis of ten different unmanned aircraft used on surveillance, reconnaissance, and search and rescue missions. The aircraft are simulated using a validated unsteady Reynolds-averaged Navier Stokes approach. The UAV's parasitic drag is significantly influenced by the presence of miscellaneous components like fixed landing gears or electro-optical sensor turrets. These components are responsible for almost half of an unmanned aircraft's total parasitic drag. The new equivalent skin friction coefficient accounts for these effects and is significantly higher compared to other aircraft categories. It is used to initially size an unmanned aircraft for a typical reconnaissance mission. The improved parasitic drag estimation yields a much heavier unmanned aircraft when compared to the sizing results using available drag data of manned aircraft.}, language = {en} } @incollection{TranTranMatthiesetal.2017, author = {Tran, N. T. and Tran, Thanh Ngoc and Matthies, M. G. and Stavroulakis, G. E. and Staat, Manfred}, title = {Shakedown Analysis Under Stochastic Uncertainty by Chance Constrained Programming}, series = {Advances in Direct Methods for Materials and Structures}, booktitle = {Advances in Direct Methods for Materials and Structures}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-59810-9}, doi = {10.1007/978-3-319-59810-9_6}, pages = {85 -- 103}, year = {2017}, abstract = {In this paper we propose a stochastic programming method to analyse limit and shakedown of structures under uncertainty condition of strength. Based on the duality theory, the shakedown load multiplier formulated by the kinematic theorem is proved actually to be the dual form of the shakedown load multiplier formulated by static theorem. In this investigation a dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit and the shakedown limit. The edge-based smoothed finite element method (ES-FEM) with three-node linear triangular elements is used for structural analysis.}, language = {en} } @incollection{DuweTippkoetterUlber2018, author = {Duwe, A. and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Lignocellulose-Biorefinery: Ethanol-Focused}, series = {Biorefineries}, booktitle = {Biorefineries}, publisher = {Springer}, address = {Cham}, doi = {10.1007/10_2016_72}, pages = {177 -- 215}, year = {2018}, abstract = {The development prospects of the world markets for petroleum and other liquid fuels are diverse and partly contradictory. However, comprehensive changes for the energy supply of the future are essential. Notwithstanding the fact that there are still very large deposits of energy resources from a geological point of view, the finite nature of conventional oil reserves is indisputable. To reduce our dependence on oil, the EU, the USA, and other major economic zones rely on energy diversification. For this purpose, alternative materials and technologies are being sought, and is most obvious in the transport sector. The objective is to progressively replace fossil fuels with renewable and more sustainable fuels. In this respect, biofuels have a pre-eminent position in terms of their capability of blending with fossil fuels and being usable in existing cars without substantial modification. Ethanol can be considered as the primary renewable liquid fuel. In this chapter enzymes, micro-organisms, and processes for ethanol production based on renewable resources are described.}, language = {en} } @article{CheenakulaHoffstadtKrafftetal.2022, author = {Cheenakula, Dheeraja and Hoffstadt, Kevin and Krafft, Simone and Reinecke, Diana and Klose, Holger and Kuperjans, Isabel and Gr{\"o}mping, Markus}, title = {Anaerobic digestion of algal-bacterial biomass of an Algal Turf Scrubber system}, series = {Biomass Conversion and Biorefinery}, volume = {13}, journal = {Biomass Conversion and Biorefinery}, publisher = {Springer}, address = {Berlin}, issn = {2190-6823}, doi = {10.1007/s13399-022-03236-z}, pages = {15 Seiten}, year = {2022}, abstract = {This study investigated the anaerobic digestion of an algal-bacterial biofilm grown in artificial wastewater in an Algal Turf Scrubber (ATS). The ATS system was located in a greenhouse (50°54′19ʺN, 6°24′55ʺE, Germany) and was exposed to seasonal conditions during the experiment period. The methane (CH4) potential of untreated algal-bacterial biofilm (UAB) and thermally pretreated biofilm (PAB) using different microbial inocula was determined by anaerobic batch fermentation. Methane productivity of UAB differed significantly between microbial inocula of digested wastepaper, a mixture of manure and maize silage, anaerobic sewage sludge, and percolated green waste. UAB using sewage sludge as inoculum showed the highest methane productivity. The share of methane in biogas was dependent on inoculum. Using PAB, a strong positive impact on methane productivity was identified for the digested wastepaper (116.4\%) and a mixture of manure and maize silage (107.4\%) inocula. By contrast, the methane yield was significantly reduced for the digested anaerobic sewage sludge (50.6\%) and percolated green waste (43.5\%) inocula. To further evaluate the potential of algal-bacterial biofilm for biogas production in wastewater treatment and biogas plants in a circular bioeconomy, scale-up calculations were conducted. It was found that a 0.116 km2 ATS would be required in an average municipal wastewater treatment plant which can be viewed as problematic in terms of space consumption. However, a substantial amount of energy surplus (4.7-12.5 MWh a-1) can be gained through the addition of algal-bacterial biomass to the anaerobic digester of a municipal wastewater treatment plant. Wastewater treatment and subsequent energy production through algae show dominancy over conventional technologies.}, language = {en} }