@article{KleinButenwegKlinkel2017, author = {Klein, Michel and Butenweg, Christoph and Klinkel, Sven}, title = {The Influence of Soil-Structure-Interaction on the Fatigue Analysis in the Foundation Design of Onshore Wind Turbines}, series = {Procedia Engineering}, volume = {199}, journal = {Procedia Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1877-7058}, doi = {10.1016/j.proeng.2017.09.325}, pages = {3218 -- 3223}, year = {2017}, language = {en} } @article{MarinkovicButenweg2019, author = {Marinkovic, Marko and Butenweg, Christoph}, title = {Innovative decoupling system for the seismic protection of masonry infill walls in reinforced concrete frames}, series = {Engineering Structures}, volume = {197}, journal = {Engineering Structures}, number = {Article 109435}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0141-0296}, doi = {10.1016/j.engstruct.2019.109435}, year = {2019}, language = {en} } @article{MichelButenwegKinkel2018, author = {Michel, Philipp and Butenweg, Christoph and Kinkel, Sven}, title = {Pile-grid foundations of onshore wind turbines considering soil-structure-interaction under seismic loading}, series = {Soil Dynamics and Earthquake Engineering}, volume = {109}, journal = {Soil Dynamics and Earthquake Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0267-7261}, doi = {10.1016/j.soildyn.2018.03.009}, pages = {299 -- 311}, year = {2018}, abstract = {In recent years, many onshore wind turbines are erected in seismic active regions and on soils with poor load bearing capacity, where pile grids are inevitable to transfer the loads into the ground. In this contribution, a realistic multi pile grid is designed to analyze the dynamics of a wind turbine tower including frequency dependent soil-structure-interaction. It turns out that different foundations on varying soil configurations heavily influence the vibration response. While the vibration amplitude is mostly attenuated, certain unfavorable combinations of structure and soil parameters lead to amplification in the range of the system's natural frequencies. This testifies the need for overall dynamic analysis in the assessment of the dynamic stability and the holistic frequency tuning of the turbines.}, language = {en} } @article{ButenwegMarinkovicKubalskietal.2016, author = {Butenweg, Christoph and Marinkovic, Marko and Kubalski, Thomas and Klinkel, Sven}, title = {Masonry infilled reinforced concrete frames under horizontal loading}, series = {Mauerwerk}, volume = {20}, journal = {Mauerwerk}, number = {4}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-1022}, doi = {10.1002/dama.201600703}, pages = {305 -- 312}, year = {2016}, abstract = {The behaviour of infilled reinforced concrete frames under horizontal load has been widely investigated, both experimentally and numerically. Since experimental tests represent large investments, numerical simulations offer an efficient approach for a more comprehensive analysis. When RC frames with masonry infill walls are subjected to horizontal loading, their behaviour is highly non-linear after a certain limit, which makes their analysis quite difficult. The non-linear behaviour results from the complex inelastic material properties of the concrete, infill wall and conditions at the wall-frame interface. In order to investigate this non-linear behaviour in detail, a finite element model using a micro modelling approach is developed, which is able to predict the complex non-linear behaviour resulting from the different materials and their interaction. Concrete and bricks are represented by a non-linear material model, while each reinforcement bar is represented as an individual part installed in the concrete part and behaving elasto-plastically. Each brick is modelled individually and connected taking into account the non-linearity of a brick mortar interface. The same approach is followed using two finite element software packages and the results are compared with the experimental results. The numerical models show a good agreement with the experiments in predicting the overall behaviour, but also very good matching for strength capacity and drift. The results emphasize the quality and the valuable contribution of the numerical models for use in parametric studies, which are needed for the derivation of design recommendations for infilled frame structures.}, language = {en} } @article{RosinButenwegKlinkel2016, author = {Rosin, Julia and Butenweg, Christoph and Klinkel, Sven}, title = {Stabilit{\"a}tsnachweis f{\"u}r seismisch beanspruchte Tankbauwerke nach dem LBA/MNA-Konzept}, series = {Bauingenieur}, volume = {91}, journal = {Bauingenieur}, number = {12}, publisher = {VDI Fachmedien}, address = {D{\"u}sseldorf}, issn = {0005-6650}, doi = {10.37544/0005-6650-2016-12-74}, pages = {518 -- 526}, year = {2016}, abstract = {Eine seismische Anregung verursacht in einem Fl{\"u}ssigkeitstank einen kombinierten Spannungszustand, was zu einem Stabilit{\"a}tsversagen der h{\"a}ufig sehr d{\"u}nnwandigen Konstruktionen f{\"u}hren kann. F{\"u}r die Durchf{\"u}hrung von Stabilit{\"a}tsnachweisen stehen verschiedene Verfahren zur Verf{\"u}gung. {\"U}blicherweise werden aus Gr{\"u}nden der Einfachheit spannungsbasierte Verfahren angewendet. Diese sind f{\"u}r Einheitslastf{\"a}lle experimentell abgesichert, wobei eine {\"U}bertragung auf kombinierte Spannungszust{\"a}nde wie im Erdbebenfall nur begrenzt m{\"o}glich ist. Alternativ kann ein globales, numerisches Konzept, das LBA/MNA-Verfahren, angewendet werden. Das Verfahren kombiniert eine materiell nichtlineare Berechnung (MNA) mit einer linearen Beulanalyse (LBA) und erfasst die Interaktion verschiedener gleichzeitig auftretender Beanspruchungen implizit im Nachweis. Dieser Beitrag demonstriert die Anwendung der Verfahren am Beispiel verschiedener Tankgeometrien mit H{\"o}he/Radius-Verh{\"a}ltnissen zwischen 1 ≤ H/R ≤ 2 und Radius/Tankwand-Verh{\"a}ltnissen zwischen 500 ≤ R/t ≤ 1000 und diskutiert zus{\"a}tzlich die Defizite der spannungsbasierten Nachweisverfahren.}, language = {de} } @article{ButenwegSchmittRosen2014, author = {Butenweg, Christoph and Schmitt, T. and Rosen, B.}, title = {Seismische Einwirkungen auf erdverlegte Rohrleitungen}, series = {Bauingenieur}, volume = {89}, journal = {Bauingenieur}, publisher = {VDI Fachmedien}, address = {D{\"u}sseldorf}, issn = {0005-6650}, pages = {316 -- 324}, year = {2014}, abstract = {Die erdbebensichere Auslegung von erdverlegten Rohrleitungssystemen ist von wesentlicher Bedeutung zur Sicherstellung der Funktionalit{\"a}t der Versorgungsinfrastruktur nach einem Erdbebenereignis. Zur Vermeidung von Netzausf{\"a}llen ist es erforderlich, die r{\"a}umlich weit ausgedehnten Leitungssysteme mit geeigneten rechnerischen Modellen seismisch zu bemessen. Der vorliegende Beitrag behandelt die Beanspruchung von Rohrleitungssystemen durch seismische Welleneinwirkung und stellt geeignete N{\"a}herungsans{\"a}tze und ein detailliertes Rechenmodell f{\"u}r seismische Leitungsanalysen vor. Mit den Ans{\"a}tzen wird in Berechnungsbeispielen der Einfluss wesentlicher Parameter auf die seismisch induzierten Dehnungen in Rohrleitungssystemen untersucht.}, language = {de} } @article{RossiHoltschoppenButenweg2019, author = {Rossi, Leonardo and Holtschoppen, Britta and Butenweg, Christoph}, title = {Official data on the economic consequences of the 2012 Emilia-Romagna earthquake: a first analysis of database SFINGE}, series = {Bulletin of Earthquake Engineering}, volume = {17}, journal = {Bulletin of Earthquake Engineering}, number = {9}, publisher = {Springer}, address = {Berlin}, doi = {10.1007\%2Fs10518-019-00655-8}, pages = {4855 -- 4884}, year = {2019}, language = {en} } @article{RossiStupazziniParisietal.2019, author = {Rossi, Leonardo and Stupazzini, Marco and Parisi, Davide and Holtschoppen, Britta and Ruggieri, Gabriella and Butenweg, Christoph}, title = {Empirical fragility functions and loss curves for long-span-beam buildings based on the 2012 Emilia-Romagna earthquake official database}, series = {Bulletin of Earthquake Engineering}, volume = {18}, journal = {Bulletin of Earthquake Engineering}, publisher = {Springer Nature}, issn = {1573-1456}, doi = {10.1007/s10518-019-00759-1}, pages = {1693 -- 1721}, year = {2019}, abstract = {The 2012 Emilia-Romagna earthquake, that mainly struck the homonymous Italian region provoking 28 casualties and damage to thousands of structures and infrastructures, is an exceptional source of information to question, investigate, and challenge the validity of seismic fragility functions and loss curves from an empirical standpoint. Among the most recent seismic events taking place in Europe, that of Emilia-Romagna is quite likely one of the best documented, not only in terms of experienced damages, but also for what concerns occurred losses and necessary reconstruction costs. In fact, in order to manage the compensations in a fair way both to citizens and business owners, soon after the seismic sequence, the regional administrative authority started (1) collecting damage and consequence-related data, (2) evaluating information sources and (3) taking care of the cross-checking of various reports. A specific database—so-called Sistema Informativo Gestione Europa (SFINGE)—was devoted to damaged business activities. As a result, 7 years after the seismic events, scientists can rely on a one-of-a-kind, vast and consistent database, containing information about (among other things): (1) buildings' location and dimensions, (2) occurred structural damages, (3) experienced direct economic losses and (4) related reconstruction costs. The present work is focused on a specific data subset of SFINGE, whose elements are Long-Span-Beam buildings (mostly precast) deployed for business activities in industry, trade or agriculture. With the available set of data, empirical fragility functions, cost and loss ratio curves are elaborated, that may be included within existing Performance Based Earthquake Engineering assessment toolkits.}, language = {en} } @article{MichelButenwegKlinkel2020, author = {Michel, P. and Butenweg, Christoph and Klinkel, S.}, title = {Einfluss der dynamischen Steifigkeit von Flach-und Pfahlgr{\"u}ndungen auf die Dynamik von Onshore-Windenergieanlagen}, series = {Bauingenieur}, volume = {95}, journal = {Bauingenieur}, number = {4}, publisher = {VDI Fachmedien}, address = {D{\"u}sseldorf}, issn = {0005-6650}, pages = {139 -- 146}, year = {2020}, language = {de} } @article{MarinkovicButenweg2020, author = {Marinkovic, Marko and Butenweg, Christoph}, title = {Earthquake-proof system for masonry infills in RC frame structures}, series = {International Journal of Masonry Research and Innovation}, volume = {5}, journal = {International Journal of Masonry Research and Innovation}, number = {2}, publisher = {Inderscience Enterprises}, address = {Olney, Bucks}, issn = {2056-9467}, doi = {10.1504/IJMRI.2020.106328}, pages = {185 -- 208}, year = {2020}, language = {de} } @article{MarinkovicButenweg2020, author = {Marinkovic, Marko and Butenweg, Christoph}, title = {Ausfachungen aus Ziegelmauerwerk in Stahlbetonrahmentragwerken unter Erdbebenbeanspruchung}, series = {Mauerwerk}, volume = {24}, journal = {Mauerwerk}, number = {4}, publisher = {Wiley}, address = {Weinheim}, issn = {1437-1022}, doi = {10.1002/dama.202000011}, pages = {194 -- 205}, year = {2020}, abstract = {Stahlbetonrahmentragwerke mit Ausfachungen aus Mauerwerk weisen nach Erdbeben h{\"a}ufig schwere Sch{\"a}den auf. Gr{\"u}nde hierf{\"u}r sind die Beanspruchungen der Ausfachungsw{\"a}nde durch die aufgezwungenen Rahmenverformungen in Wandebene und die gleichzeitig auftretenden Tr{\"a}gheitskr{\"a}fte senkrecht zur Wandebene in Kombination mit der konstruktiven Ausf{\"u}hrung des Ausfachungsmauerwerks. Die Ausfachung wird in der Regel knirsch gegen die Rahmenst{\"u}tzen gemauert, wobei der Verschluss der oberen Fuge mit M{\"o}rtel oder Montageschaum erfolgt. Dadurch kommt es im Erdbebenfall zu lokalen Interaktionen zwischen Ausfachung und Rahmen, die in der Folge zu einem Versagen einzelner Ausfachungsw{\"a}nde oder zu einem sukzessiven Versagen des Gesamtgeb{\"a}udes f{\"u}hren k{\"o}nnen. Die beobachteten Sch{\"a}den waren die Motivation daf{\"u}r, in dem europ{\"a}ischen Forschungsprojekt INSYSME f{\"u}r Stahlbetonrahmentragwerke mit Ausfachungen aus hochw{\"a}rmed{\"a}mmenden Ziegelmauerwerk innovative L{\"o}sungen zur Verbesserung des seismischen Verhaltens zu entwickeln. Der vorliegende Beitrag stellt die im Rahmen des Projekts von den deutschen Projektpartnern (Universit{\"a}t Kassel, SDA-engineering GmbH) entwickelten L{\"o}sungen vor und vergleicht deren seismisches Verhalten mit der traditionellen Ausf{\"u}hrung der Ausfachungsw{\"a}nde. Grundlage f{\"u}r den Vergleich sind statisch-zyklische Wandversuche und Simulationen auf Wandebene. Aus den Ergebnissen werden Empfehlungen f{\"u}r die erdbebensichere Auslegung von Stahlbetonrahmentragwerken mit Ausfachungen aus Ziegelmauerwerk abgeleitet.}, language = {de} } @article{ButenwegRosin2020, author = {Butenweg, Christoph and Rosin, Julia}, title = {Seismischer Nachweis von Mauerwerksbauten in deutschen Erdbebengebieten}, series = {Mauerwerk}, volume = {24}, journal = {Mauerwerk}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {1437-1022}, doi = {10.1002/dama.202000006}, pages = {108 -- 113}, year = {2020}, abstract = {Mit finanzieller Unterst{\"u}tzung der Deutschen Gesellschaft f{\"u}r Mauerwerks- und Wohnungsbau e.V. (DGfM) und des Deutschen Instituts f{\"u}r Bautechnik in Berlin (DIBt) wurden zwei aufeinander aufbauende Forschungsvorhaben zur Verbesserung der seismischen Nachweise von Mauerwerksbauten in deutschen Erdbebengebieten durchgef{\"u}hrt. Zun{\"a}chst wurde das seismische Verhalten von drei modernen unbewehrten Mauerwerksgeb{\"a}uden in der Region Emilia Romagna in Italien w{\"a}hrend der Erdbebenserie im Jahr 2012 in Kooperation mit der Universit{\"a}t Pavia eingehend untersucht. Aufbauend auf den Erkenntnissen dieser Untersuchungen wurde ein verbessertes seismisches Bemessungskonzept f{\"u}r unbewehrte Mauerwerksbauten erarbeitet. Der Beitrag stellt die wesentlichen Ergebnisse dieser Forschungsarbeiten und deren Eingang in die Normung vor.}, language = {de} } @article{ElDeibButenwegKlinkel2020, author = {El-Deib, Khaled and Butenweg, Christoph and Klinkel, Sven}, title = {Erdbebennachweis von Mauerwerksbauten mit realistischen Modellen und erh{\"o}hten Verhaltensbeiwerten}, series = {Bautechnik}, volume = {97}, journal = {Bautechnik}, number = {11}, publisher = {Ernst \& Sohn}, address = {Berlin}, doi = {10.1002/bate.202000016}, pages = {756 -- 765}, year = {2020}, abstract = {Die Anwendung des linearen Nachweiskonzepts auf Mauerwerksbauten f{\"u}hrt dazu, dass bereits heute Standsicherheitsnachweise f{\"u}r Geb{\"a}ude mit {\"u}blichen Grundrissen in Gebieten mit moderaten Erdbebeneinwirkungen nicht mehr gef{\"u}hrt werden k{\"o}nnen. Diese Problematik wird sich in Deutschland mit der Einf{\"u}hrung kontinuierlicher probabilistischer Erdbebenkarten weiter versch{\"a}rfen. Aufgrund der Erh{\"o}hung der seismischen Einwirkungen, die sich vielerorts ergibt, ist es erforderlich, die vorhandenen, bislang nicht ber{\"u}cksichtigten Tragf{\"a}higkeitsreserven in nachvollziehbaren Nachweiskonzepten in der Baupraxis verf{\"u}gbar zu machen. Der vorliegende Beitrag stellt ein Konzept f{\"u}r die geb{\"a}udespezifische Ermittlung von erh{\"o}hten Verhaltensbeiwerten vor. Die Verhaltensbeiwerte setzen sich aus drei Anteilen zusammen, mit denen die Lastumverteilung im Grundriss, die Verformungsf{\"a}higkeit und Energiedissipation sowie die {\"U}berfestigkeiten ber{\"u}cksichtigt werden. F{\"u}r die rechnerische Ermittlung dieser drei Anteile wird ein nichtlineares Nachweiskonzept auf Grundlage von Pushover-Analysen vorgeschlagen, in denen die Interaktionen von W{\"a}nden und Geschossdecken durch einen Einspanngrad beschrieben werden. F{\"u}r die Bestimmung der Einspanngrade wird ein nichtlinearer Modellierungsansatz eingef{\"u}hrt, mit dem die Interaktion von W{\"a}nden und Decken abgebildet werden kann. Die Anwendung des Konzepts mit erh{\"o}hten geb{\"a}udespezifischen Verhaltensbeiwerten wird am Beispiel eines Mehrfamilienhauses aus Kalksandsteinen demonstriert. Die Ergebnisse der linearen Nachweise mit erh{\"o}hten Verhaltensbeiwerten f{\"u}r dieses Geb{\"a}ude liegen deutlich n{\"a}her an den Ergebnissen nichtlinearer Nachweise und somit bleiben {\"u}bliche Grundrisse in Erdbebengebieten mit den traditionellen linearen Rechenans{\"a}tzen nachweisbar.}, language = {de} } @article{VargaDavinsonGloriusetal.2020, author = {Varga, Laszlo and Davinson, Thomas and Glorius, Jan and Jurado, Beatrix and Langer, Christoph and Lederer-Woods, Claudia and Litvinov, Yuri A. and Reifarth, Rene and Slavkovska, Zuzana and St{\"o}hlker, Thomas and Woods, Phil J. and Xing, Yuan Ming}, title = {Towards background-free studies of capture reaction in a heavy-ion storage ring}, series = {Journal of Physics: Conference Series}, volume = {1668}, journal = {Journal of Physics: Conference Series}, number = {Art 012046}, publisher = {IOP}, address = {Bristol}, year = {2020}, abstract = {Stored and cooled, highly-charged ions offer unprecedented capabilities for precision studies in the realm of atomic, nuclear structure and astrophysics[1]. After the successful investigation of the 96Ru(p,7)97Rh reaction cross section in 2009[2], the first measurement of the 124Xe(p,7)125Cs reaction cross section has been performed with decelerated, fully-ionized 124Xe ions in 2016 at the Experimental Storage Ring (ESR) of GSI[3]. Using a Double Sided Silicon Strip Detector, introduced directly into the ultra-high vacuum environment of a storage ring, the 125Cs proton-capture products have been successfully detected. The cross section has been measured at 5 different energies between 5.5AMeV and 8AMeV, on the high energy tail of the Gamow-window for hot, explosive scenarios such as supernovae and X-ray binaries. The elastic scattering on the H2 gas jet target is the major source of background to count the (p,7) events. Monte Carlo simulations show that an additional slit system in the ESR in combination with the energy information of the Si detector will enable background free measurements of the proton-capture products. The corresponding hardware is being prepared and will increase the sensitivity of the method tremendously.}, language = {en} } @article{HenriquesJuradoGrieseretal.2020, author = {Henriques, A. and Jurado, B. and Grieser, M. and Denis-Petit, D. and Chiron, T. and Gaudefroy, L. and Glorius, J. and Langer, Christoph and Litvinov, Yu. A. and Mathieu, L. and Meot, V. and Perez-Sanchez, R. and Pibernat, J. and Reifarth, R. and Roig, O. and Thomas, B. and Thomas, B. A. and Thomas, J. C. and Tsekhanovich, I.}, title = {Indirect measurements of neutron cross-secti at heavy-ion storage rings}, series = {Journal of Physics: Conference Series}, volume = {1668}, journal = {Journal of Physics: Conference Series}, number = {Art. 012019}, publisher = {IOP}, address = {Bristol}, doi = {10.1088/1742-6596/1668/1/012019}, year = {2020}, abstract = {Cross sections for neutron-induced reactions of short-lived nuclei are essential for nuclear astrophysics since these reactions in the stars are responsible for the production of most heavy elements in the universe. These reactions are also key in applied domains like energy production and medicine. Nevertheless, neutron-induced cross-section measurements can be extremely challenging or even impossible to perform due to the radioactivity of the targets involved. Indirect measurements through the surrogate-reaction method can help to overcome these difficulties. The surrogate-reaction method relies on the use of an alternative reaction that will lead to the formation of the same excited nucleus as in the neutron-induced reaction of interest. The decay probabilities (for fission, neutron and gamma-ray emission) of the nucleus produced via the surrogate reaction allow one to constrain models and the prediction of the desired neutron cross sections. We propose to perform surrogate reaction measurements in inverse kinematics at heavy-ion storage rings, in particular at the CRYRING@ESR of the GSI/FAIR facility. We present the conceptual idea of the most promising setup to measure for the first time simultaneously the fission, neutron and gamma-ray emission probabilities. The results of the first simulations considering the 238U(d,d') reaction are shown, as well as new technical developments that are being carried out towards this set-up.}, 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{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{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{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{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} }