@article{Kern2016, author = {Kern, Alexander}, title = {Blitz- und {\"U}berspannungsschutz von Kernkraftwerken - Nachweisf{\"u}hrung der ausreichenden Sicherheit f{\"u}r leittechnische Einrichtungen auch bei Blitzeinschl{\"a}gen mit extremen Parametern}, series = {Atw. International Journal for Nuclear Power}, volume = {61}, journal = {Atw. International Journal for Nuclear Power}, number = {8/9}, publisher = {Inforum}, address = {Berlin}, issn = {1431-5254}, pages = {534 -- 543}, year = {2016}, abstract = {F{\"u}r das Auftreten extremer Wetterereignisse werden f{\"u}r Kernkraftwerke Eintrittsh{\"a}ufigkeiten f{\"u}r nicht mehr beherrschbare Zust{\"a}nde von unter 10⁻⁴/a gefordert. Dies gilt auch f{\"u}r die Einwirkung von Blitzeinschl{\"a}gen. Die bisherige Nachweisf{\"u}hrung zu Blitz- und {\"U}berspannungsschutz eines KKW in Deutschland ist deterministisch. In diesem Bericht werden das Vorgehen f{\"u}r einen entsprechenden Nachweis f{\"u}r leittechnische Einrichtungen der Sicherheitstechnik von KKW, der zur geforderten Zielgr{\"o}ße der Eintrittsh{\"a}ufigkeit f{\"u}hrt. Die Ergebnisse werden zusammenfassend bewertet.}, language = {de} } @article{AlexopoulosHoffschmidt2017, author = {Alexopoulos, Spiros and Hoffschmidt, Bernhard}, title = {Advances in solar tower technology}, series = {Wiley interdisciplinary reviews : Energy and Environment : WIREs}, volume = {6}, journal = {Wiley interdisciplinary reviews : Energy and Environment : WIREs}, number = {1}, publisher = {Wiley}, address = {Weinheim}, issn = {2041-840X}, doi = {10.1002/wene.217}, pages = {1 -- 19}, year = {2017}, language = {en} } @article{SrivastavaChaharSharmaetal.2017, author = {Srivastava, A. and Chahar, V. and Sharma, V. and Sun, Y. and Bol, R. and Knolle, F. and Schnug, E. and Hoyler, Friedrich and Naskar, N. and Lahiri, S. and Patnaik, R.}, title = {Study of uranium toxicity using low-background gamma-ray spectrometry}, series = {Journal of Radioanalytical and Nuclear Chemistry}, journal = {Journal of Radioanalytical and Nuclear Chemistry}, number = {Online first}, publisher = {Springer}, address = {Berlin}, issn = {1588-2780}, doi = {10.1007/s10967-017-5466-9}, pages = {1 -- 7}, year = {2017}, language = {en} } @article{RiekeStollenwerkDahmenetal.2018, author = {Rieke, Christian and Stollenwerk, Dominik and Dahmen, Markus and Pieper, Martin}, title = {Modeling and optimization of a biogas plant for a demand-driven energy supply}, series = {Energy}, volume = {145}, journal = {Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0360-5442}, doi = {10.1016/j.energy.2017.12.073}, pages = {657 -- 664}, year = {2018}, abstract = {Due to the Renewable Energy Act, in Germany it is planned to increase the amount of renewable energy carriers up to 60\%. One of the main problems is the fluctuating supply of wind and solar energy. Here biogas plants provide a solution, because a demand-driven supply is possible. Before running such a plant, it is necessary to simulate and optimize the process. This paper provides a new model of a biogas plant, which is as accurate as the standard ADM1 model. The advantage compared to ADM1 is that it is based on only four parameters compared to 28. Applying this model, an optimization was installed, which allows a demand-driven supply by biogas plants. Finally the results are confirmed by several experiments and measurements with a real test plant.}, language = {en} } @article{RuppHandschuhRiekeetal.2019, author = {Rupp, Matthias and Handschuh, Nils and Rieke, Christian and Kuperjans, Isabel}, title = {Contribution of country-specific electricity mix and charging time to environmental impact of battery electric vehicles: A case study of electric buses in Germany}, series = {Applied Energy}, volume = {237}, journal = {Applied Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0306-2619}, doi = {10.1016/j.apenergy.2019.01.059}, pages = {618 -- 634}, year = {2019}, language = {en} } @article{DotzauerPfeifferLaueretal.2019, author = {Dotzauer, Martin and Pfeiffer, Diana and Lauer, Markus and Pohl, Marcel and Mauky, Eric and B{\"a}r, Katharina and Sonnleitner, Matthias and Z{\"o}rner, Wilfried and Hudde, Jessica and Schwarz, Bj{\"o}rn and Faßauer, Burkhardt and Dahmen, Markus and Rieke, Christian and Herbert, Johannes and Thr{\"a}n, Daniela}, title = {How to measure flexibility - Performance indicators for demand driven power generation from biogas plants}, series = {Renewable Energy}, journal = {Renewable Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0960-1481}, doi = {10.1016/j.renene.2018.10.021}, pages = {135 -- 146}, year = {2019}, language = {en} } @article{RegerKuhnhenneHachuletal.2019, author = {Reger, Vitali and Kuhnhenne, Markus and Hachul, Helmut and D{\"o}ring, Bernd and Blanke, Tobias and G{\"o}ttsche, Joachim}, title = {Plusenergiegeb{\"a}ude 2.0 in Stahlleichtbauweise}, series = {Stahlbau}, volume = {88}, journal = {Stahlbau}, number = {6}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-1049 (E-journal), 0038-9145 (print)}, doi = {10.1002/stab.201900034}, pages = {522 -- 528}, year = {2019}, language = {de} } @article{HerrmannSchwarzenbartDittmannGabriel2019, author = {Herrmann, Ulf and Schwarzenbart, Marc and Dittmann-Gabriel, S{\"o}ren}, title = {Speicher statt Kohle. Integration thermischer Stromspeicher in vorhandene Kraftwerksstandorte}, series = {BWK : Das Energie-Fachmagazin}, volume = {71}, journal = {BWK : Das Energie-Fachmagazin}, number = {4}, publisher = {Springer-VDI-Verl.}, address = {D{\"u}sseldorf}, issn = {1436-4883}, pages = {42 -- 45}, year = {2019}, language = {de} } @article{BirklDiendorferKernetal.2018, author = {Birkl, Josef and Diendorfer, Gerhard and Kern, Alexander and Thern, Stephan}, title = {Extrem hohe Blitzstr{\"o}me}, series = {Elektropraktiker}, volume = {72}, journal = {Elektropraktiker}, number = {3}, publisher = {Huss Medien}, address = {Berlin}, pages = {217 -- 225}, year = {2018}, abstract = {Blitze sind nach wie vor eine enorme Schadensquelle f{\"u}r Personensch{\"a}den, Br{\"a}nde, mechanische Zerst{\"o}rungen und insbesondere auch {\"U}berspannungen. Das zeigen nicht zuletzt aktuelle Statistiken der Schadensversicherer. Immer wieder gibt es Meldungen {\"u}ber extrem hohe Blitzstr{\"o}me, die nat{\"u}rlich auch zu großen Sch{\"a}den und Zerst{\"o}rungen f{\"u}hren k{\"o}nnen. Dabei werden Scheitelwerte von teilweise deutlich {\"u}ber 300 kA genannt. Dies wirft Fragen auf, da die „klassische" Blitzstatistik (z. B. nach CIGRE und IEC [8][10]) bisher solche Werte nicht kennt. Diese extremen Blitzstr{\"o}me werden meist aus den Daten von Blitzortungssystemen ermittelt.}, language = {de} } @article{KellerRathBruckmannetal.2020, author = {Keller, Johannes and Rath, Volker and Bruckmann, Johanna and Mottaghy, Darius and Clauser, Christoph and Wolf, Andreas and Seidler, Ralf and B{\"u}cker, H. Martin and Klitzsch, Norbert}, title = {SHEMAT-Suite: An open-source code for simulating flow, heat and species transport in porous media}, series = {SoftwareX}, volume = {12}, journal = {SoftwareX}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-7110}, doi = {10.1016/j.softx.2020.100533}, pages = {9}, year = {2020}, abstract = {SHEMAT-Suite is a finite-difference open-source code for simulating coupled flow, heat and species transport in porous media. The code, written in Fortran-95, originates from geoscientific research in the fields of geothermics and hydrogeology. It comprises: (1) a versatile handling of input and output, (2) a modular framework for subsurface parameter modeling, (3) a multi-level OpenMP parallelization, (4) parameter estimation and data assimilation by stochastic approaches (Monte Carlo, Ensemble Kalman filter) and by deterministic Bayesian approaches based on automatic differentiation for calculating exact (truncation error-free) derivatives of the forward code.}, language = {en} } @article{NobisSchmittSchemmetal.2020, author = {Nobis, Moritz and Schmitt, Carlo and Schemm, Ralf and Schnettler, Armin}, title = {Pan-European CVAR-constrained stochastic unit commitment in day-ahead and intraday electricity markets}, series = {Energies}, volume = {13}, journal = {Energies}, number = {Art. 2339}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {10.3390/en13092339}, pages = {1 -- 35}, year = {2020}, abstract = {The fundamental modeling of energy systems through individual unit commitment decisions is crucial for energy system planning. However, current large-scale models are not capable of including uncertainties or even risk-averse behavior arising from forecasting errors of variable renewable energies. However, risks associated with uncertain forecasting errors have become increasingly relevant within the process of decarbonization. The intraday market serves to compensate for these forecasting errors. Thus, the uncertainty of forecasting errors results in uncertain intraday prices and quantities. Therefore, this paper proposes a two-stage risk-constrained stochastic optimization approach to fundamentally model unit commitment decisions facing an uncertain intraday market. By the nesting of Lagrangian relaxation and an extended Benders decomposition, this model can be applied to large-scale, e.g., pan-European, power systems. The approach is applied to scenarios for 2023—considering a full nuclear phase-out in Germany—and 2035—considering a full coal phase-out in Germany. First, the influence of the risk factors is evaluated. Furthermore, an evaluation of the market prices shows an increase in price levels as well as an increasing day-ahead-intraday spread in 2023 and in 2035. Finally, it is shown that intraday cross-border trading has a significant influence on trading volumes and prices and ensures a more efficient allocation of resources.}, language = {en} } @article{SattlerRoegerSchwarzboezletal.2020, author = {Sattler, Johannes, Christoph and R{\"o}ger, Marc and Schwarzb{\"o}zl, Peter and Buck, Reiner and Macke, Ansgar and Raeder, Christian and G{\"o}ttsche, Joachim}, title = {Review of heliostat calibration and tracking control methods}, series = {Solar Energy}, volume = {207}, journal = {Solar Energy}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.solener.2020.06.030}, pages = {110 -- 132}, year = {2020}, abstract = {Large scale central receiver systems typically deploy between thousands to more than a hundred thousand heliostats. During solar operation, each heliostat is aligned individually in such a way that the overall surface normal bisects the angle between the sun's position and the aim point coordinate on the receiver. Due to various tracking error sources, achieving accurate alignment ≤1 mrad for all the heliostats with respect to the aim points on the receiver without a calibration system can be regarded as unrealistic. Therefore, a calibration system is necessary not only to improve the aiming accuracy for achieving desired flux distributions but also to reduce or eliminate spillage. An overview of current larger-scale central receiver systems (CRS), tracking error sources and the basic requirements of an ideal calibration system is presented. Leading up to the main topic, a description of general and specific terms on the topics heliostat calibration and tracking control clarifies the terminology used in this work. Various figures illustrate the signal flows along various typical components as well as the corresponding monitoring or measuring devices that indicate or measure along the signal (or effect) chain. The numerous calibration systems are described in detail and classified in groups. Two tables allow the juxtaposition of the calibration methods for a better comparison. In an assessment, the advantages and disadvantages of individual calibration methods are presented.}, language = {en} } @article{HoffstadtPohenDickeetal.2020, author = {Hoffstadt, Kevin and Pohen, Gino D. and Dicke, Max D. and Paulsen, Svea and Krafft, Simone and Zang, Joachim W. and Fonseca-Zang, Warde A. da and Leite, Athaydes and Kuperjans, Isabel}, title = {Challenges and prospects of biogas from energy cane as supplement to bioethanol production}, series = {Agronomy}, volume = {10}, journal = {Agronomy}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2073-4395}, doi = {10.3390/agronomy10060821}, year = {2020}, abstract = {Innovative breeds of sugar cane yield up to 2.5 times as much organic matter as conventional breeds, resulting in a great potential for biogas production. The use of biogas production as a complementary solution to conventional and second-generation ethanol production in Brazil may increase the energy produced per hectare in the sugarcane sector. Herein, it was demonstrated that through ensiling, energy cane can be conserved for six months; the stored cane can then be fed into a continuous biogas process. This approach is necessary to achieve year-round biogas production at an industrial scale. Batch tests revealed specific biogas potentials between 400 and 600 LN/kgVS for both the ensiled and non-ensiled energy cane, and the specific biogas potential of a continuous biogas process fed with ensiled energy cane was in the same range. Peak biogas losses through ensiling of up to 27\% after six months were observed. Finally, compared with second-generation ethanol production using energy cane, the results indicated that biogas production from energy cane may lead to higher energy yields per hectare, with an average energy yield of up to 162 MWh/ha. Finally, the Farm²CBG concept is introduced, showing an approach for decentralized biogas production.}, language = {en} } @article{HeelDiktaBraekers2021, author = {Heel, Mareike van and Dikta, Gerhard and Braekers, Roel}, title = {Bootstrap based goodness‑of‑fit tests for binary multivariate regression models}, series = {Journal of the Korean Statistical Society}, volume = {51}, journal = {Journal of the Korean Statistical Society}, publisher = {Springer Nature}, address = {Singapur}, issn = {2005-2863 (Online)}, doi = {10.1007/s42952-021-00142-4}, pages = {28 Seiten}, year = {2021}, abstract = {We consider a binary multivariate regression model where the conditional expectation of a binary variable given a higher-dimensional input variable belongs to a parametric family. Based on this, we introduce a model-based bootstrap (MBB) for higher-dimensional input variables. This test can be used to check whether a sequence of independent and identically distributed observations belongs to such a parametric family. The approach is based on the empirical residual process introduced by Stute (Ann Statist 25:613-641, 1997). In contrast to Stute and Zhu's approach (2002) Stute \& Zhu (Scandinavian J Statist 29:535-545, 2002), a transformation is not required. Thus, any problems associated with non-parametric regression estimation are avoided. As a result, the MBB method is much easier for users to implement. To illustrate the power of the MBB based tests, a small simulation study is performed. Compared to the approach of Stute \& Zhu (Scandinavian J Statist 29:535-545, 2002), the simulations indicate a slightly improved power of the MBB based method. Finally, both methods are applied to a real data set.}, 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} } @article{SteuerDankertSharmaBlecketal.2017, author = {Steuer-Dankert, Linda and Sharma, Mamta Rameshwarlal and Bleck, Wolfgang and Leicht-Scholten, Carmen}, title = {Diversity and innovation management in large research groups}, series = {International Journal of Innovation Management}, volume = {5}, journal = {International Journal of Innovation Management}, number = {2}, issn = {1757-5877}, pages = {49 -- 72}, year = {2017}, abstract = {Contemporary research appreciates a diverse workforce as a potential source of innovation. Researchers explore the fine details of why diversity management is central for generating innovations in heterogeneous research groups and how it could be effectively implemented into organizations. Complex research associations that discuss topics with a high impact on society increasingly address the necessity of establishing a diverse workforce to confront the challenges of tomorrow. Characterized by complex management structures as well as hierarchies, research associations have not been a subject of investigation until now. For this reason, the presented research project aims to develop a diversity and innovation management strategy with the ultimate goal of inducing change in the corporate culture. The proposed approach consisted of six phases; the first two phases investigated the status quo of diversity in the existing organizational structures of member institutes and the variety of particular working cultures within the research association. The third and the fourth phases utilized qualitative and quantitative studies. The third phase focused on the connection of management level to diversity and innovation, and the need for diversity and innovation management, and tailor-made methods of implementing them. The first three phases have been accomplished successfully; preliminary results are already available. The fourth phase will mainly focus on exploring the mind-set of the employees. The fifth phase will consolidate the findings in the first four phases into an implementable strategy. The final phase will address the implementation of this strategy into the organization. Phases 4 to 6 have not yet been undertaken}, language = {en} } @article{SteuerDankertGilmartinMulleretal.2019, author = {Steuer-Dankert, Linda and Gilmartin, Shannon K. and Muller, Carol B. and Dungs, Carolin and Sheppard, Sheri and Leicht-Scholten, Carmen}, title = {Expanding engineering limits : a concept for socially responsible education of engineers}, series = {The international journal of engineering education}, volume = {35}, journal = {The international journal of engineering education}, number = {2}, isbn = {0949-149X}, pages = {658 -- 673}, year = {2019}, language = {en} } @article{KahmannRauschPluemeretal.2022, author = {Kahmann, Stephanie L. and Rausch, Valentin and Pl{\"u}mer, Jonathan and M{\"u}ller, Lars P. and Pieper, Martin and Wegmann, Kilian}, title = {The automized fracture edge detection and generation of three-dimensional fracture probability heat maps}, series = {Medical Engineering \& Physics}, volume = {2022}, journal = {Medical Engineering \& Physics}, number = {110}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1350-4533}, pages = {7 Seiten}, year = {2022}, abstract = {With proven impact of statistical fracture analysis on fracture classifications, it is desirable to minimize the manual work and to maximize repeatability of this approach. We address this with an algorithm that reduces the manual effort to segmentation, fragment identification and reduction. The fracture edge detection and heat map generation are performed automatically. With the same input, the algorithm always delivers the same output. The tool transforms one intact template consecutively onto each fractured specimen by linear least square optimization, detects the fragment edges in the template and then superimposes them to generate a fracture probability heat map. We hypothesized that the algorithm runs faster than the manual evaluation and with low (< 5 mm) deviation. We tested the hypothesis in 10 fractured proximal humeri and found that it performs with good accuracy (2.5 mm ± 2.4 mm averaged Euclidean distance) and speed (23 times faster). When applied to a distal humerus, a tibia plateau, and a scaphoid fracture, the run times were low (1-2 min), and the detected edges correct by visual judgement. In the geometrically complex acetabulum, at a run time of 78 min some outliers were considered acceptable. An automatically generated fracture probability heat map based on 50 proximal humerus fractures matches the areas of high risk of fracture reported in medical literature. Such automation of the fracture analysis method is advantageous and could be extended to reduce the manual effort even further.}, language = {en} } @article{SchwagerFleschSchwarzboezletal.2022, author = {Schwager, Christian and Flesch, Robert and Schwarzb{\"o}zl, Peter and Herrmann, Ulf and Teixeira Boura, Cristiano Jos{\´e}}, title = {Advanced two phase flow model for transient molten salt receiver system simulation}, series = {Solar Energy}, volume = {232}, journal = {Solar Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0038-092X (print)}, doi = {10.1016/j.solener.2021.12.065}, pages = {362 -- 375}, year = {2022}, abstract = {In order to realistically predict and optimize the actual performance of a concentrating solar power (CSP) plant sophisticated simulation models and methods are required. This paper presents a detailed dynamic simulation model for a Molten Salt Solar Tower (MST) system, which is capable of simulating transient operation including detailed startup and shutdown procedures including drainage and refill. For appropriate representation of the transient behavior of the receiver as well as replication of local bulk and surface temperatures a discretized receiver model based on a novel homogeneous two-phase (2P) flow modelling approach is implemented in Modelica Dymola®. This allows for reasonable representation of the very different hydraulic and thermal properties of molten salt versus air as well as the transition between both. This dynamic 2P receiver model is embedded in a comprehensive one-dimensional model of a commercial scale MST system and coupled with a transient receiver flux density distribution from raytracing based heliostat field simulation. This enables for detailed process prediction with reasonable computational effort, while providing data such as local salt film and wall temperatures, realistic control behavior as well as net performance of the overall system. Besides a model description, this paper presents some results of a validation as well as the simulation of a complete startup procedure. Finally, a study on numerical simulation performance and grid dependencies is presented and discussed.}, language = {en} } @article{EdipSesovButenwegetal.2018, author = {Edip, K. and Sesov, V. and Butenweg, Christoph and Bojadjieva, J.}, title = {Development of coupled numerical model for simulation of multiphase soil}, series = {Computers and Geotechnics}, volume = {96}, journal = {Computers and Geotechnics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0266-352X}, doi = {10.1016/j.compgeo.2017.08.016}, pages = {118 -- 131}, year = {2018}, abstract = {In this paper, a coupled multiphase model considering both non-linearities of water retention curves and solid state modeling is proposed. The solid displacements and the pressures of both water and air phases are unknowns of the proposed model. The finite element method is used to solve the governing differential equations. The proposed method is demonstrated through simulation of seepage test and partially consolidation problem. Then, implementation of the model is done by using hypoplasticity for the solid phase and analyzing the fully saturated triaxial experiments. In integration of the constitutive law error controlling is improved and comparisons done accordingly. In this work, the advantages and limitations of the numerical model are discussed.}, language = {en} }