02 Fakultät Bau- und Umweltingenieurwissenschaften
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3
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Item Open Access The 10th International Conference on Life Cycle Management 2021 : Stuttgart, Germany, September 05-08, 2021(2021) Fischer, Matthias; Barkmeyer, Mercedes; Albrecht, Stefan; Braune, Anna; Leistner, Philip; Seifert, Rainer; Kreissig, JohannesItem Open Access The 2‐methylpropene degradation pathway in Mycobacteriaceae family strains(2023) Helbich, Steffen; Barrantes, Israel; dos Anjos Borges, Luiz Gustavo; Pieper, Dietmar H.; Vainshtein, Yevhen; Sohn, Kai; Engesser, Karl‐HeinrichMycolicibacterium gadium IBE100 and Mycobacterium paragordonae IBE200 are aerobic, chemoorganoheterotrophic bacteria isolated from activated sludge from a wastewater treatment plant. They use 2‐methylpropene (isobutene, 2‐MP) as the sole source of carbon and energy. Here, we postulate a degradation pathway of 2‐methylpropene derived from whole genome sequencing, differential expression analysis and peptide‐mass fingerprinting. Key genes identified are coding for a 4‐component soluble diiron monooxygenase with epoxidase activity, an epoxide hydrolase, and a 2‐hydroxyisobutyryl‐CoA mutase. In both strains, involved genes are arranged in clusters of 61.0 and 58.5 kbp, respectively, which also contain the genes coding for parts of the aerobic pathway of adenosylcobalamin synthesis. This vitamin is essential for the carbon rearrangement reaction catalysed by the mutase. These findings provide data for the identification of potential 2‐methylpropene degraders.Item Open Access Accuracy of fully coupled and sequential approaches for modeling hydro- and geomechanical processes(2020) Beck, M.; Rinaldi, A. P.; Flemisch, B.; Class, H.Subsurface flow and geomechanics are often modeled with sequential approaches. This can be computationally beneficial compared with fully coupled schemes, while it requires usually compromises in numerical accuracy, at least when the sequential scheme is non-iterative. We discuss the influence of the choice of scheme on the numerical accuracy and the expected computational effort based on a comparison of a fully coupled scheme, a scheme employing a one-way coupling, and an iterative scheme using a fixed-stress split for two subsurface injection scenarios. All these schemes were implemented in the numerical simulator DuMux. This study identifies conditions of problem settings where differences due to the choice of the model approach are as important as differences in geologic features. It is shown that in particular transient and multiphase flow, effects can be causing significant deviations between non-iterative and iterative sequential schemes, which might be in the same order of magnitude as geologic uncertainty. An iterated fixed-stress split has the same numerical accuracy as a fully coupled scheme but only for a certain number of iterations which might use up the computational advantage of solving two smaller systems of equations rather than a big monolithical one.Item Open Access Adapting Santiago method to determine appropriate and resource efficient sanitation systems for an urban settlement in Lima Peru(2021) Nisaa, Ainul Firdatun; Krauss, Manuel; Spuhler, DorotheeThe pre-selection of locally appropriate sanitation technologies and systems is crucial for strategic sanitation planning as any decision is only as good as the options presented. One approach that allows us to systematically consider the local conditions and a diverse range of conventional and novel technologies and systems is the Santiago method. In this paper, we discuss whether the Santiago method can be applied to the case of Latin America and what we would gain from this application. We do so by expanding the Santiago technology library with technologies that have been shown to be promising in metropolitan areas of Latin America, such as condominial sewer, container-based sanitation, and activated sludge. We then apply Santiago to the semi-informal settlement Quebrada Verde (QV) in Lima, Peru. Using Santiago, we were able to generate 265,185 sanitation system options from 42 technologies and 18 appropriateness criteria. A set of 17 appropriate and divers are then selected. The diversity is defined by 17 system templates. To further evaluate these 17 systems, resource recovery and loss potentials are quantified. Higher nutrients (nitrogen and phosphorus) and total solids recovery are observed for systems that combine urine diversion and biofuel production. The case of QV shows that the Santiago method is applicable in the Latin American context.Item Open Access An adaptive hybrid vertical equilibrium/full‐dimensional model for compositional multiphase flow(2022) Becker, Beatrix; Guo, Bo; Buntic, Ivan; Flemisch, Bernd; Helmig, RainerEfficient compositional models are required to simulate underground gas storage in porous formations where, for example, gas quality (such as purity) and loss of gas due to dissolution are of interest. We first extend the concept of vertical equilibrium (VE) to compositional flow, and derive a compositional VE model by vertical integration. Second, we present a hybrid model that couples the efficient compositional VE model to a compositional full‐dimensional model. Subdomains, where the compositional VE model is valid, are identified during simulation based on a VE criterion that compares the vertical profiles of relative permeability at equilibrium to the ones simulated by the full‐dimensional model. We demonstrate the applicability of the hybrid model by simulating hydrogen storage in a radially symmetric, heterogeneous porous aquifer. The hybrid model shows excellent adaptivity over space and time for different permeability values in the heterogeneous region, and compares well to the full‐dimensional model while being computationally efficient, resulting in a runtime of roughly one‐third of the full‐dimensional model. Based on the results, we assume that for larger simulation scales, the efficiency of this new model will increase even more.Item Open Access Adjustment of the life cycle inventory in life cycle assessment for the flexible integration into energy systems analysis(2020) Betten, Thomas; Shammugam, Shivenes; Graf, RobertaItem Open Access Adsorption of metals to particles in urban stormwater runoff : does size really matter?(2021) Baum, Philipp; Kuch, Bertram; Dittmer, UlrichThe parameter total suspended solids (TSS) is often used to evaluate the need for stormwater treatment or to assess the effectiveness of treatment measures. The purpose of this study is to analyze the value and the limitations of this approach using metals as an example. They are of major concern due to their accumulating effects in the environment. Data of a monitoring campaign at a stormwater treatment facility is evaluated. TSS, organic matter and the associated metals (Cr, Cu, Zn, Cd, and Pb) were analyzed in four different particle size fractions (<63 µm, 63-125 µm, 125-250 µm, and 250-2000 µm). While the highest event meant concentrations for all metals were found in the smallest fraction, a rather uniform particulate bound metal concentration (mass of metal per mass of particulate matter) over the first three particle size fractions was detected. Total metal loads correlated well with TSS even better with TSS < 63 µm. However, the removal efficiency in terms of the reduction of the total metal load was not reflected sufficiently by the TSS or TSS < 63 µm removal efficiency.Item Open Access Advanced methods to investigate hydro‐morphological processes in open‐water environments(2021) Haun, Stefan; Dietrich, StephanHydro‐morphology describes the interactions between water and sediments in fluvial systems and the corresponding processes across all spatial and temporal scales. The results are natural and anthropogenically influenced bed structures and fluvial landforms. However, many of these hydro‐morphological processes cannot be described analytically yet, as a result of their stochastic behaviour and the multitude of processes involved across spatial and temporal scales. Deeper knowledge of these processes is essential, not only for understanding the system itself, but also for practical applications, which rely on correct and reliable investigations of these processes. During the European Geoscience Union (EGU) General Assembly (GA) 2018 in Vienna, Austria, the conveners of the session on “Measurements, monitoring and numerical modelling of sedimentary and hydro‐morphological processes in open‐water environments” had the idea of initiating a special issue, containing a collection of recent achievements in this research field. The aim of this extended introduction is twofold. First, an overview on research needs in investigating hydro‐morphological processes in open‐water environments is given in this article. Second, recently published studies that aim to improve the understanding of hydro‐morphological processes in rivers, lakes and reservoirs by innovative measurement approaches are discussed. In addition to submitted papers collected from the EGU GA in 2017, 2018 and 2019, related studies published in Earth Surface Processes and Landforms (ESPL) over the last two years are also incorporated into this special issue. The papers selected cover a wide range of studies with differing spatial and temporal resolutions. This broad spectrum of different scales clearly indicates the challenges associated with the development and use of advanced methods for investigating hydro‐morphological processes in open‐water environments.Item Open Access Analysing the bone cement flow in the injection apparatus during vertebroplasty(2023) Trivedi, Zubin; Gehweiler, Dominic; Wychowaniec, Jacek K.; Ricken, Tim; Gueorguiev-Rüegg, Boyko; Wagner, Arndt; Röhrle, OliverVertebroplasty, a medical procedure for treating vertebral fractures, requires medical practitioners to inject bone cement inside the vertebra using a cannula attached to a syringe. The required injection force must be small enough for the practitioner to apply it by hand while remaining stable for a controlled injection. Several factors could make the injection force unintuitive for the practitioners, one of them being the non‐Newtonian nature of the bone cement. The viscosity of the bone cement varies as it flows through the different parts of the injection apparatus and the porous cancellous interior of the vertebra. Therefore, it is important to study the flow of bone cement through these parts. This work is a preliminary study on the flow of bone cement through the injection apparatus. Firstly, we obtained the rheological parameters for the power law model of bone cement using experiments using standard clinical equipment. These parameters were then used to obtain the shear rate, viscosity, and velocity profiles of the bone cement flow through the cannula. Lastly, an analysis was carried out to understand the influence of various geometrical parameters of the injection apparatus, in which the radius of the cannula was found to be the most influential parameter.Item Open Access Analysis of experimental and simulation data of evaporation‐driven isotopic fractionation in unsaturated porous media(2024) Schneider, Jana; Kiemle, Stefanie; Heck, Katharina; Rothfuss, Youri; Braud, Isabelle; Helmig, Rainer; Vanderborght, JanStable water isotopologs can add valuable information to the understanding of evaporation processes. The identification of the evaporation front from isotopolog concentration depth profiles under very dry soil conditions is of particular interest. We compared two different models that describe isotopolog transport in a drying unsaturated porous medium: SiSPAT‐Isotope and DuMu x . In DuMu x , the medium can dry out completely whereas in SiSPAT‐Isotope, drying is limited to the residual water saturation. We evaluated the impact of residual water saturation on simulated isotopic concentration. For a low residual water saturation, both models simulated similar isotopolog concentrations. For high residual water saturation, SiSPAT‐Isotope simulated considerably lower concentrations than DuMu x . This is attributed to the buffering of changes in isotopolog concentrations by the residual water in SiSPAT‐Isotope and an additional enrichment due to evaporation of residual water in DuMu x . Additionally, we present a comparison between high‐frequency experimental data and model simulations. We found that diffusive transport processes in the laminar boundary layer and in the dried‐out surface soil layer need to be represented correctly to reproduce the observed downward movement of the evaporation front and the associated peak of isotopolog enrichment. Artificially increasing the boundary layer thickness to reproduce a decrease in evaporation rate leads to incorrect simulation of the location of the evaporation front and isotopolog concentration profile.Item Open Access Analysis of fatigue test data to reassess EN 1993‐1‐9 detail categories(2020) Bartsch, Helen; Drebenstedt, Karl; Seyfried, Benjamin; Feldmann, Markus; Kuhlmann, Ulrike; Ummenhofer, ThomasThis paper addresses the assessment of fatigue details according to EN 1993‐1‐9, which form the basis of the most important fatigue verification, the nominal stress approach. First of all, a suitable statistical methodology had to be defined for consistent detail classification. A structured database on the MySQL platform serves as a basis for the evaluation of the detail categories. In addition to fatigue test data documented in the background document to EN 1993‐1‐9, this database also includes new test data provided by the authors. After selecting the most meaningful test data, important details, such as longitudinal welds, were reassessed. In addition, the authors carried out fatigue tests in connection with numerical simulations in order to be able to evaluate the fatigue strength with better accuracy. The results so far show that the details analysed often prove to have a higher fatigue strength than currently documented in EN 1993‐1‐9.Item Open Access Ansprüche an die Siedlungswasserwirtschaft - Kernaufgaben versus weitergehende Anforderungen(Essen : Vulkan-Verlag GmbH, 2019) Eberlein, Joachim; Baumann, Peter; Kreuzinger, Norbert; Anders, Gereon; Böhm, Bernhard; Marthaler, Roland; Dittmer, Ulrich; Alt, Klaus; Barnscheidt, Inge; Reichert, Andreas; Vossler, Johann; Schönberger, Harald; Meyer, Carsten; Krauß, ManuelDie Herausforderungen an die Kommunalabwasserbehandlung steigen immer weiter: Mikroschadstoffeliminierung, Nährstoffrückgewinnung, Abwasserdesinfektion, Energieeffizienzsteigerung und vielleicht auch in naher Zukunft die Mikroplastikentfernung. Daneben besteht nach wie vor die klassische Aufgabe der Eliminierung von Kohlenstoff- und Nährstoffverbindungen, an die auch immer höhere Ansprüche gestellt werden. Wie können die Abwasseranlagenbetreiber all diese Aufgaben meistern? Müssen aus Sicht des Gewässerschutzes Prioritäten gesetzt werden? Welche Betriebserfahrungen gibt es mit neuartigen Technologien? Stehen die weitergehenden Anforderungen in Konkurrenz zu den bisherigen Kernaufgaben oder können Synergien sowohl bei der Technologie als auch im Betrieb entstehen?Item Open Access Application of super absorbent polymers (SAP) in concrete construction : update of RILEM state-of-the-art report(2021) Mechtcherine, Viktor; Wyrzykowski, Mateusz; Schröfl, Christof; Snoeck, Didier; Lura, Pietro; De Belie, Nele; Mignon, Arn; Vlierberghe, Sandra van; Klemm, Agnieszka J.; Almeida, Fernando C. R.; Tenório Filho, José Roberto; Boshoff, William Peter; Reinhardt, Hans-Wolf; Igarashi, Shin-IchiSuperabsorbent polymers (SAP) are a new, promising class of chemical admixtures which offer new possibilities in respect of influencing the properties of cement-based materials in the fresh, hardening, and hardened states. Much research work has been done in the last two decades to set the stage for introducing this truly multipurpose agent into the practice of construction. In particular, three RILEM Technical Committees: 196-ICC, 225-SAP and 260-RSC contributed considerably to the related progress by coordinating and combining the efforts of international experts in the field. The major product of the RILEM TC 225-SAP work was the State-of-the-Art Report published in 2012. This comprehensive document covered all topics relevant to the application of SAP as a concrete admixture. Since then further important progress has been made in understanding the working mechanisms of SAP in concrete and the effects of SAP-addition on various concrete properties. The article at hand presents an update on the state-of-the-art and is the concluding document delivered by the RILEM TC 260-RSC.Item Open Access Artificial instabilities of finite elements for nonlinear elasticity : analysis and remedies(2023) Bieber, Simon; Auricchio, Ferdinando; Reali, Alessandro; Bischoff, ManfredWithin the framework of plane strain nonlinear elasticity, we present a discussion on the stability properties of various Enhanced Assumed Strain (EAS) finite element formulations with respect to physical and artificial (hourglassing) instabilities. By means of a linearized buckling analysis we analyze the influence of element formulations on the geometric stiffness and provide new mechanical insights into the hourglassing phenomenon. Based on these findings, a simple strategy to avoid hourglassing for compression problems is proposed. It is based on a modification of the discrete Green-Lagrange strain, simple to implement and generally applicable. The stabilization concept is tested for various popular element formulations (namely EAS elements and the assumed stress element by Pian and Sumihara). A further aspect of the present contribution is a discussion on proper benchmarking of finite elements in the context of hourglassing. We propose a simple bifurcation problem for which analytical solutions are readily available in the literature. It is tailored for an in-depth stability analysis of finite elements and allows a reliable assessment of its stability properties.Item Open Access Assessing data in the informal e-waste sector: The Agbogbloshie Scrapyard(2021) Owusu-Sekyere, Karoline; Batteiger, Alexander; Afoblikame, Richard; Hafner, Gerold; Kranert, MartinItem Open Access Assessing land use efficiencies and land quality impacts of renewable transportation energy systems for passenger cars using the LANCA method(2022) Uusitalo, Ville; Horn, Rafael; Maier, Stephanie D.Targets to reduce global warming impacts of the transportation sector may lead to increased land use and negative land quality changes. The aim of this paper is to implement the Land Use Indicator Calculation in Life Cycle Assessment (LANCA®) model to assess land quality impacts and land use efficiencies (concerning occupation and transformation) of different example renewable transport energy systems for passenger cars. In addition, the land use impacts are normalized according to the Soil Quality Index building on LANCA® and included in the environmental footprint. The assessment is based on information from GaBi life cycle assessment software databases and on literature. Functional unit of the model is to provide annual drive of 18,600 km for a passenger car in the EU. The analysis includes examples of biomass, electricity, electricity to fuels and fossil-based energy systems. Our findings confirm previous research that biomass-based transport energy systems have risks to lead to significantly higher land occupation and transformation impacts than do fossil oil or electricity-based ones. According to the LANCA® model, methane from Finnish wood and German corn has the highest impacts on filtration and the physicochemical filtration reduction potential. Sugarcane ethanol and palm oil diesel systems, on the other hand, lead to the highest erosion potential. Electricity-based transportation energy systems appear to be superior to biomass-based ones from the perspectives of land occupation, land transformation, and soil quality impacts for the selected examples. Land quality impacts should be taken into account when developing and expanding renewable transportation energy systems. The paper shows that the LANCA® method is applicable for the assessment of transport systems in order to provide extended information on environmental sustainability, which should be included more often in future analysis. However, it can be challenging to interpret underlaying assumptions, especially when aggregated information is used from databases.Item Open Access Assessing rainfall radar errors with an inverse stochastic modelling framework(2024) Green, Amy C.; Kilsby, Chris; Bárdossy, AndrásWeather radar is a crucial tool for rainfall observation and forecasting, providing high-resolution estimates in both space and time. Despite this, radar rainfall estimates are subject to many error sources - including attenuation, ground clutter, beam blockage and drop-size distribution - with the true rainfall field unknown. A flexible stochastic model for simulating errors relating to the radar rainfall estimation process is implemented, inverting standard weather radar processing methods and imposing path-integrated attenuation effects, a stochastic drop-size-distribution field, and sampling and random errors. This can provide realistic weather radar images, of which we know the true rainfall field and the corrected “best-guess” rainfall field which would be obtained if they were observed in a real-world case. The structure of these errors is then investigated, with a focus on the frequency and behaviour of “rainfall shadows”. Half of the simulated weather radar images have at least 3 % of their significant rainfall rates shadowed, and 25 % have at least 45 km 2 containing rainfall shadows, resulting in underestimation of the potential impacts of flooding. A model framework for investigating the behaviour of errors relating to the radar rainfall estimation process is demonstrated, with the flexible and efficient tool performing well in generating realistic weather radar images visually for a large range of event types.Item Open Access Assessment of uncertainties in a complex modeling chain for predicting reservoir sedimentation under changing climate(2023) Pesci, María Herminia; Mouris, Kilian; Haun, Stefan; Förster, KristianLong-term predictions of reservoir sedimentation require an objective consideration of the preceding catchment processes. In this study, we apply a complex modeling chain to predict sedimentation processes in the Banja reservoir (Albania). The modeling chain consists of the water balance model WaSiM, the soil erosion and sediment transport model combination RUSLE-SEDD, and the 3d hydro-morphodynamic reservoir model SSIIM2 to accurately represent all relevant physical processes. Furthermore, an ensemble of climate models is used to analyze future scenarios. Although the capabilities of each model enable us to obtain satisfying results, the propagation of uncertainties in the modeling chain cannot be neglected. Hence, approximate model parameter uncertainties are quantified with the First-Order Second-Moment (FOSM) method. Another source of uncertainty for long-term predictions is the spread of climate projections. Thus, we compared both sources of uncertainties and found that the uncertainties generated by climate projections are 408% (for runoff), 539% (for sediment yield), and 272% (for bed elevation in the reservoir) larger than the model parameter uncertainties. We conclude that (i) FOSM is a suitable method for quantifying approximate parameter uncertainties in a complex modeling chain, (ii) the model parameter uncertainties are smaller than the spread of climate projections, and (iii) these uncertainties are of the same order of magnitude as the change signal for the investigated low-emission scenario. Thus, the proposed method might support modelers to communicate different sources of uncertainty in complex modeling chains, including climate impact models.Item Open Access An automated modular heating solution for experimental flow‐through stream mesocosm systems(2023) Madge Pimentel, Iris; Rehsen, Philipp M.; Beermann, Arne J.; Leese, Florian; Piggott, Jeremy J.; Schmuck, SebastianWater temperature is a key environmental variable in stream ecosystems determining species distribution ranges, community composition, and ecological processes. In addition to global warming, direct anthropogenic impacts, for example through the influx of power plant cooling water or due to sun exposure after the removal of riparian vegetation, result in elevated water temperatures. However, temperature effects in stream ecosystems have mostly been tested in recirculating experimental systems, which can neither capture diurnal and seasonal variability in other environmental variables nor allow for entrainment of stream organisms. In contrast, open flow‐through systems, which are constantly supplied with stream water, offer a more realistic setting for stream ecological experiments, yet are difficult to implement. Here, we outline a heating module for the purpose of differential temperature regulation in a flow‐through mesocosm system by automatic control of warm water supply. We validated the functionality of the module in indoor trials as well as in an outdoor ExStream experimental mesocosm system. Furthermore, we tested the implications of different warm water temperatures for the survival of invertebrates drifting through the heating module to derive recommendations for the maximum warm water temperature for mixing with the natural water inflow. The module allows for controlled open flow‐through experiments in the field and the key components are flexible and scalable. Therefore, the module can be easily integrated into existing experimental flow‐through setups.Item Open Access Bayesian calibration and validation of a large‐scale and time‐demanding sediment transport model(2020) Beckers, Felix; Heredia, Andrés; Noack, Markus; Nowak, Wolfgang; Wieprecht, Silke; Oladyshkin, SergeyThis study suggests a stochastic Bayesian approach for calibrating and validating morphodynamic sediment transport models and for quantifying parametric uncertainties in order to alleviate limitations of conventional (manual, deterministic) calibration procedures. The applicability of our method is shown for a large‐scale (11.0 km) and time‐demanding (9.14 hr for the period 2002-2013) 2‐D morphodynamic sediment transport model of the Lower River Salzach and for three most sensitive input parameters (critical Shields parameter, grain roughness, and grain size distribution). Since Bayesian methods require a significant number of simulation runs, this work proposes to construct a surrogate model, here with the arbitrary polynomial chaos technique. The surrogate model is constructed from a limited set of runs (n=20) of the full complex sediment transport model. Then, Monte Carlo‐based techniques for Bayesian calibration are used with the surrogate model (105 realizations in 4 hr). The results demonstrate that following Bayesian principles and iterative Bayesian updating of the surrogate model (10 iterations) enables to identify the most probable ranges of the three calibration parameters. Model verification based on the maximum a posteriori parameter combination indicates that the surrogate model accurately replicates the morphodynamic behavior of the sediment transport model for both calibration (RMSE = 0.31 m) and validation (RMSE = 0.42 m). Furthermore, it is shown that the surrogate model is highly effective in lowering the total computational time for Bayesian calibration, validation, and uncertainty analysis. As a whole, this provides more realistic calibration and validation of morphodynamic sediment transport models with quantified uncertainty in less time compared to conventional calibration procedures.