@article{Lahmer, author = {Lahmer, Tom}, title = {FEM-Based determination of real and complex elastic, dielectric, and piezoelectric moduli in piezoceramic materials}, series = {IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control}, journal = {IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control}, doi = {10.25643/bauhaus-universitaet.3608}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20171030-36083}, abstract = {We propose an enhanced iterative scheme for the precise reconstruction of piezoelectric material parameters from electric impedance and mechanical displacement measurements. It is based on finite-element simulations of the full three-dimensional piezoelectric equations, combined with an inexact Newton or nonlinear Landweber iterative inversion scheme. We apply our method to two piezoelectric materials and test its performance. For the first material, the manufacturer provides a full data set; for the second one, no material data set is available. For both cases, our inverse scheme, using electric impedance measurements as input data, performs well.}, subject = {Finite-Elemente-Methode}, language = {en} } @phdthesis{Staeudel, author = {St{\"a}udel, J{\"u}rgen}, title = {Development, Implementation and Operation of Integrated Sanitation Systems Based on Material-Flows - Integrated Sanitation in the City of Darkhan, Mongolia - A Practicable Example}, doi = {10.25643/bauhaus-universitaet.3179}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170512-31794}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The world society faces a huge challenge to implement the human right of "access to sanitation". More and more it is accepted that the conventional approach towards providing sanitation services is not suitable to solve this problem. This dissertation examines the possibility to enhance "access to sanitation" for people who are living in areas with underdeveloped water and wastewater infrastructure systems. The idea hereby is to follow an integrated approach for sanitation, which allows for a mutual completion of existing infrastructure with resource-based sanitation systems. The notion "integrated sanitation system (iSaS)" is defined in this work and guiding principles for iSaS are formulated. Further on the implementation of iSaS is assessed at the example of a case study in the city of Darkhan in Mongolia. More than half of Mongolia's population live in settlements where yurts (tents of Nomadic people) are predominant. In these settlements (or "ger areas") sanitation systems are not existent and the hygienic situation is precarious. An iSaS has been developed for the ger areas in Darkhan and tested over more than two years. Further on a software-based model has been developed with the goal to describe and assess different variations of the iSaS. The results of the assessment of material-flows, monetary-flows and communication-flows within the iSaS are presented in this dissertation. The iSaS model is adaptable and transferable to the socio-economic conditions in other regions and climate zones.}, subject = {Abwasser}, language = {en} } @phdthesis{MeyerKohlstock, author = {Meyer-Kohlstock, Daniel}, title = {Prospects for Biochar in a Bio-Waste Cascade}, doi = {10.25643/bauhaus-universitaet.3631}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20171108-36310}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {118}, abstract = {In the early 2000s the pre-Columbian, anthropologically produced black soil in the Amazon basin, „Terra Preta de {\´I}ndio", received greater scientific attention. Compared to the surrounding poor soils, this very fertile anthrosol contains significantly higher levels of microorganisms and nutrients. The reason for this was determined to be the likewise high levels of charred biomass. This stable carbon, now called biochar, has since been intensively examined as an option to improve soil and to store carbon. Although the creation of Terra Preta was most likely based on a purposeful utilization of organic residues from households and gardens, biochar plays no role in the current recycling of bio-waste. However, the implementation of biochar could lead to many improvements. Results from agricultural research suggest that not only the yield capacity of soils can be increased but also the process performance of composting and biogas plants. The latter is especially relevant since currently about 40\% of all collected bio-waste in Germany is recycled in an energy-material cascade consisting of anaerobic digestion and composting. The use of biochar in this cascade could then sequentially increase biogas yields, reduce greenhouse gas emissions, and improve compost quality. To realize the aforementioned advantages, the concept of biochar has to be integrated into the existing bio-waste cascade as practically as possible. This was done by the development of a theoretical scenario that allowed the analysis of energy and material flows to evaluate biochar's recycling performance. Furthermore, the legal and economic framework were examined to assess the feasibility of the extended cascade and to suggest possible adjustments to the frameworks.}, subject = {Kompost}, language = {en} } @phdthesis{Habtemariam, author = {Habtemariam, Abinet Kifle}, title = {Generalized Beam Theory for the analysis of thin-walled circular pipe members}, doi = {10.25643/bauhaus-universitaet.4572}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220127-45723}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {188}, abstract = {The detailed structural analysis of thin-walled circular pipe members often requires the use of a shell or solid-based finite element method. Although these methods provide a very good approximation of the deformations, they require a higher degree of discretization which causes high computational costs. On the other hand, the analysis of thin-walled circular pipe members based on classical beam theories is easy to implement and needs much less computation time, however, they are limited in their ability to approximate the deformations as they cannot consider the deformation of the cross-section. This dissertation focuses on the study of the Generalized Beam Theory (GBT) which is both accurate and efficient in analyzing thin-walled members. This theory is based on the separation of variables in which the displacement field is expressed as a combination of predetermined deformation modes related to the cross-section, and unknown amplitude functions defined on the beam's longitudinal axis. Although the GBT was initially developed for long straight members, through the consideration of complementary deformation modes, which amend the null transverse and shear membrane strain assumptions of the classical GBT, problems involving short members, pipe bends, and geometrical nonlinearity can also be analyzed using GBT. In this dissertation, the GBT formulation for the analysis of these problems is developed and the application and capabilities of the method are illustrated using several numerical examples. Furthermore, the displacement and stress field results of these examples are verified using an equivalent refined shell-based finite element model. The developed static and dynamic GBT formulations for curved thin-walled circular pipes are based on the linear kinematic description of the curved shell theory. In these formulations, the complex problem in pipe bends due to the strong coupling effect of the longitudinal bending, warping and the cross-sectional ovalization is handled precisely through the derivation of the coupling tensors between the considered GBT deformation modes. Similarly, the geometrically nonlinear GBT analysis is formulated for thin-walled circular pipes based on the nonlinear membrane kinematic equations. Here, the initial linear and quadratic stress and displacement tangent stiffness matrices are built using the third and fourth-order GBT deformation mode coupling tensors. Longitudinally, the formulation of the coupled GBT element stiffness and mass matrices are presented using a beam-based finite element formulation. Furthermore, the formulated GBT elements are tested for shear and membrane locking problems and the limitations of the formulations regarding the membrane locking problem are discussed.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{AlaladeNguyenTuanWuttkeetal., author = {Alalade, Muyiwa and Nguyen-Tuan, Long and Wuttke, Frank and Lahmer, Tom}, title = {Damage identification in gravity dams using dynamic coupled hydro-mechanical XFEM}, series = {International Journal of Mechanics and Materials in Design}, journal = {International Journal of Mechanics and Materials in Design}, doi = {10.25643/bauhaus-universitaet.3596}, pages = {1 -- 19}, abstract = {Damage identification in gravity dams using dynamic coupled hydro-mechanical XFEM.}, subject = {Angewandte Mathematik}, language = {en} } @article{MehlingSchnabelLondong, author = {Mehling, Simon and Schnabel, Tobias and Londong, J{\"o}rg}, title = {Investigation on Energetic Efficiency of Reactor Systems for Oxidation of Micro-Pollutants by Immobilized Active Titanium Dioxide Photocatalysis}, series = {Water}, volume = {2022}, journal = {Water}, number = {Volume 14, issue 7, article 2681}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/w14172681}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220912-47130}, pages = {1 -- 15}, abstract = {In this work, the degradation performance for the photocatalytic oxidation of eight micropollutants (amisulpride, benzotriazole, candesartan, carbamazepine, diclofenac, gabapentin, methlybenzotriazole, and metoprolol) within real secondary effluent was investigated using three different reactor designs. For all reactor types, the influence of irradiation power on its reaction rate and energetic efficiency was investigated. Flat cell and batch reactor showed almost similar substance specific degradation behavior. Within the immersion rotary body reactor, benzotriazole and methylbenzotriazole showed a significantly lower degradation affinity. The flat cell reactor achieved the highest mean degradation rate, with half time values ranging from 5 to 64 min with a mean of 18 min, due to its high catalysts surface to hydraulic volume ratio. The EE/O values were calculated for all micro-pollutants as well as the mean degradation rate constant of each experimental step. The lowest substance specific energy per order (EE/O) values of 5 kWh/m3 were measured for benzotriazole within the batch reactor. The batch reactor also reached the lowest mean values (11.8-15.9 kWh/m3) followed by the flat cell reactor (21.0-37.0 kWh/m3) and immersion rotary body reactor (23.9-41.0 kWh/m3). Catalyst arrangement and irradiation power were identified as major influences on the energetic performance of the reactors. Low radiation intensities as well as the use of submerged catalyst arrangement allowed a reduction in energy demand by a factor of 3-4. A treatment according to existing treatment goals of wastewater treatment plants (80\% total degradation) was achieved using the batch reactor with a calculated energy demand of 7000 Wh/m3.}, subject = {Fotokatalyse}, language = {en} } @article{SoebkeLueck, author = {S{\"o}bke, Heinrich and L{\"u}ck, Andrea}, title = {Framing Algorithm-Driven Development of Sets of Objectives Using Elementary Interactions}, series = {Applied System Innovation}, volume = {2022}, journal = {Applied System Innovation}, number = {Volume 5, issue 3, article 49}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/asi5030049}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20220713-46624}, pages = {1 -- 20}, abstract = {Multi-criteria decision analysis (MCDA) is an established methodology to support the decision-making of multi-objective problems. For conducting an MCDA, in most cases, a set of objectives (SOO) is required, which consists of a hierarchical structure comprised of objectives, criteria, and indicators. The development of an SOO is usually based on moderated development processes requiring high organizational and cognitive effort from all stakeholders involved. This article proposes elementary interactions as a key paradigm of an algorithm-driven development process for an SOO that requires little moderation efforts. Elementary interactions are self-contained information requests that may be answered with little cognitive effort. The pairwise comparison of elements in the well-known analytical hierarchical process (AHP) is an example of an elementary interaction. Each elementary interaction in the development process presented contributes to the stepwise development of an SOO. Based on the hypothesis that an SOO may be developed exclusively using elementary interactions (EIs), a concept for a multi-user platform is proposed. Essential components of the platform are a Model Aggregator, an Elementary Interaction Stream Generator, a Participant Manager, and a Discussion Forum. While the latter component serves the professional exchange of the participants, the first three components are intended to be automatable by algorithms. The platform concept proposed has been evaluated partly in an explorative validation study demonstrating the general functionality of the algorithms outlined. In summary, the platform concept suggested demonstrates the potential to ease SOO development processes as the platform concept does not restrict the application domain; it is intended to work with little administration moderation efforts, and it supports the further development of an existing SOO in the event of changes in external conditions. The algorithm-driven development of SOOs proposed in this article may ease the development of MCDA applications and, thus, may have a positive effect on the spread of MCDA applications.}, subject = {Multikriteria-Entscheidung}, language = {en} } @inproceedings{FediorHamel, author = {Fedior, Marco and Hamel, Wido}, title = {Simulationsumgebung zur Evaluation von umweltorientierten Verkehrsmanagement-Strategien}, series = {30. Forum Bauinformatik}, booktitle = {30. Forum Bauinformatik}, editor = {Steiner, Maria and Theiler, Michael and Mirboland, Mahsa}, organization = {Bauhaus-Universit{\"a}t Weimar}, doi = {10.25643/bauhaus-universitaet.3867}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20190328-38678}, pages = {6}, abstract = {Der vorliegende Beitrag beschreibt die Problematik bei der Prognose verkehrsbedingter Schadstoff-Immissionen. Im Mittelpunkt steht die Entwicklung und der Aufbau einer Simulationsumgebung zur Evaluation von umweltorientierten Verkehrsmanagement-Strategien. Die Simulationsumgebung wird {\"u}ber die drei Felder Verkehr, Emission, Immission entwickelt und findet zun{\"a}chst Anwendung in der Evaluation verkehrlicher Maßnahmen f{\"u}r die Friedberger Landstraße in Frankfurt am Main.}, subject = {Verkehr}, language = {de} } @phdthesis{Weitze, author = {Weitze, Laura Katharina}, title = {Erweiterte Prozessbewertung von Biogasanlagen unter Ber{\"u}cksichtigung organoleptischer Parameter und Erfahrungswissen}, doi = {10.25643/bauhaus-universitaet.3849}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20190129-38499}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {308}, abstract = {Landwirtschaftliche Biogasanlagen leisten mit ca. 9.300 Anlagen und einem Anteil von 5,3\% an der Stromerzeugung, einen Beitrag zur Erzeugung Erneuer-barer Energien in Deutschland. Die Optimierung dieser Anlagen f{\"o}rdert die nachhaltige Bereitstellung von Strom, W{\"a}rme und BioErdgas. Das Ergebnis dieser Forschungsarbeit ist die Entwicklung eines mehrmethodi-schen Bewertungsansatzes zur Beschreibung der Qualit{\"a}t der Eingangs-substrate als Teil einer ganzheitlichen Prozessoptimierung. Dies gelingt durch die kombinierte Nutzung klassischer Analyses{\"a}tze, der Nutzung organolepti-scher Parameter - der humansensorischen Sinnenpr{\"u}fung - und der Integration von prozess- und substratspezifischem Erfahrungswissen. Anhand von halbtechnischen Versuchen werden Korrelationen und Kausalit{\"a}ten zwi-schen chemisch-physikalischen, biologischen, organoleptischen und erfahrungsbezogenen Parametern erforscht. Die Entwicklung einer Fallbasis mit Hilfe des Fallbasierten Schließens, einer Form K{\"u}nstlicher Intelligenz, zeigt das Entwicklungs- und Integrationspotenzial der Automatisierung auf, insbesondere auch im Hinblick auf neue Ans{\"a}tze z.B. Industrie 4.0. Erste L{\"o}sungen zur Bew{\"a}ltigung der identifizierten Herausforderungen der mehrmethodischen Prozessbewertung werden vorgestellt. Abschließend wird ein Ausblick auf den weiteren Forschungsbedarf gegeben und die {\"U}bertragbarkeit des mehrmethodischen Bewertungsansatzes auf andere Anwendungsfelder z.B. Bioabfallbehandlung, Kl{\"a}ranlagen angeregt.}, subject = {Biogasanlage}, language = {de} } @article{LondongBarthSoebke, author = {Londong, J{\"o}rg and Barth, Marcus and S{\"o}bke, Heinrich}, title = {Modeling and Simulation of Source Separation in Sanitation Systems for Reducing Emissions of Antimicrobial Resistances}, series = {Water}, volume = {2021}, journal = {Water}, number = {Volume 13, issue 23, article 3342}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/w13233342}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20211202-45338}, pages = {1 -- 19}, abstract = {Antimicrobial resistance (AMR) is identified by the World Health Organization (WHO) as one of the top ten threats to public health worldwide. In addition to public health, AMR also poses a major threat to food security and economic development. Current sanitation systems contribute to the emergence and spread of AMR and lack effective AMR mitigation measures. This study assesses source separation of blackwater as a mitigation measure against AMR. A source-separation-modified combined sanitation system with separate collection of blackwater and graywater is conceptually described. Measures taken at the source, such as the separate collection and discharge of material flows, were not considered so far on a load balance basis, i.e., they have not yet been evaluated for their effectiveness. The sanitation system described is compared with a combined system and a separate system regarding AMR emissions by means of simulation. AMR is represented in the simulation model by one proxy parameter each for antibiotics (sulfamethoxa-zole), antibiotic-resistant bacteria (extended-spectrum beta-lactamase E. Coli), and antibiotic re-sistance genes (blaTEM). The simulation results suggest that the source-separation-based sanitation system reduces emissions of antibiotic-resistant bacteria and antibiotic resistance genes into the aquatic environment by more than six logarithm steps compared to combined systems. Sulfa-methoxazole emissions can be reduced by 75.5\% by keeping blackwater separate from graywater and treating it sufficiently. In summary, sanitation systems incorporating source separation are, to date, among the most effective means of preventing the emission of AMR into the aquatic envi-ronment.}, subject = {Abwasser}, language = {en} }