Deep Green
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/12328
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Item Open Access Li‐Ion storage and diffusivity in sulfurized polybutadiene containing covalently bound sulfur as a polysulfide shuttle‐free cathode material for Li-S batteries(2024) Muduli, Sadananda; Boecker, Marcel; Prädel, Leon; Neumann, Christof; Du, Qian; Buchmeiser, Michael R.In this work, a new polymer has been explored as a cathode host for lithium‐sulfur batteries (LSBs). Sulfurized polybutadiene materials were synthesized by a single‐step, scalable, and easily tailored heat treatment method. The optimized synthesis process allows for high sulfur loadings of up to 50 wt %. Thermogravimetric analysis‐mass spectrometry (TGA‐MS) and X‐ray photoelectron spectroscopy (XPS) studies confirm that the sulfur is covalently bound to the polymeric backbone, which overcomes the otherwise common capacity‐fading polysulfide shuttle effect of lithium‐sulfur (LSBs) batteries. The absence of free elemental sulfur in the synthesized active materials allows for a stable capacity of up to 1200 mAh g -1 at a rate of C/20. The porous polymer networks reduce the pulverization of the cathode during cycling, resulting in long‐term cycling stability of 1500 continuous galvanostatic charge/discharge (GCD) cycles. Capacity contribution studies depict that at a scan rate of 1 mV s -1 , the sulfurized polybutadiene cathode‐based cells have 65 % capacitive and 35 % diffusive contribution of the total charge stored. A comprehensive study on Li‐ion storage with capacity contribution and diffusion studies of polysulfide shuttle‐free sulfurized polybutadiene cathode material for LSBs is presented.Item Open Access Multi-objective optimization of a folding photovoltaic-integrated light shelf using non-dominated sorting genetic algorithm III for enhanced daylighting and energy savings in office buildings(2025) Cheraghzad, Tanin; Zamani, Zahra; Hakimazari, Mohammad; Norouzi, Masoud; Karimi, AlirezaThis study developed a novel folding light shelf system that integrates reflectors, photovoltaic (PV) modules, and adaptive louvers that adjust based on solar altitude, aiming to improve daylight distribution, minimize glare, and reduce energy consumption in office buildings. The research employed an advanced optimization approach, utilizing Non-dominated Sorting Genetic Algorithm III (NSGA-III) and Latin Hypercube Sampling, a highly effective method suitable for managing complex multi-objective scenarios involving numerous variables, to efficiently identify high-performance configurations with increased precision. Key design variables across all three components of the system included angle, width, distance, and the number of folds in the light shelf, along with the number of louvers. The proposed method successfully integrates PV technology into light shelves without compromising their functionality, enabling both daylight control and energy generation. The optimization results demonstrate that the system achieved up to a 15% improvement in useful daylight illuminance (UDI) and a 16% reduction in cooling energy consumption. Furthermore, the PV modules generated 509.5 kWh/year, ensuring improved efficiency and sustainability in building performance.Item Open Access Biodegradable, antibacterial TCP implant coatings with magnesium phosphate‐based supraparticles(2025) Lanzino, Maria Carolina; Höppel, Anika; Le, Long‐Quan R. V.; Morelli, Stefania; Killinger, Andreas; Rheinheimer, Wolfgang; Mayr, Hermann O.; Dembski, Sofia; Al‐Ahmad, Ali; Mayr, Moritz F.; Gbureck, Uwe; Seidenstuecker, MichaelThis work highlights the potential of porous, bioactive coatings to advance implant technology and address critical clinical challenges. A key issue in implant coatings is to achieve the balance between infection prevention and successful osseointegration. Although titanium implants are widely used due to their mechanical strength and biocompatibility, their bioinert nature limits integration with bone tissue. To address these issues, porous calcium phosphate (CaP) coatings have been developed to enhance cell attachment and bone growth. However, CaP, especially in the widely used form of hydroxyapatite (HAp), has a low resorption rate, which often leads to prolonged coating stability and impairs natural bone remodeling. To overcome this limitation, magnesium phosphate (MgP), an underexplored but promising biomaterial with high biocompatibility and osteogenic potential, can be introduced. Another innovative strategy is the doping of biomaterials with antibacterial ions, among which copper (Cu) has attracted particular attention. The incorporation of Cu into the coating matrix can significantly reduce the risk of post‐operative infection while promoting angiogenesis, a key factor for rapid and stable implant integration. This study presents bone implant coatings composed of tricalcium phosphate (TCP) and Cu‐doped MgP clustered nanoparticles (supraparticles) fabricated via high‐velocity suspension flame spraying (HVSFS). This particle system addresses current challenges in bone tissue regeneration by synergistically combining the high biodegradability of MgP, the bone‐mimicking properties of CaP, and the antibacterial capabilities of Cu. In addition, the HVSFS process enables the creation of thin layers with porous microstructures. Biocompatibility of the prepared coatings was assessed using MG63 osteosarcoma cells, while the antibacterial efficacy was tested against Staphylococcus aureus and Escherichia coli . The incorporation of Cu‐doped MgP supraparticles (MgPCu and MgPCu HT) into TCP coatings resulted in high Cu release and pronounced antibacterial efficacy compared to the TCP reference, while the addition of Cu‐doped FT supraparticles (FTCu) led to high cell proliferation.Item Open Access Co‐doping approach for enhanced electron extraction to TiO2 for stable inorganic perovskite solar cells(2025) Gries, Thomas W.; Regaldo, Davide; Köbler, Hans; Putri Hartono, Noor Titan; Harvey, Steven P.; Simmonds, Maxim; Frasca, Chiara; Härtel, Marlene; Sannino, Gennaro V.; Félix, Roberto; Hüsam, Elif; Saleh, Ahmed; Wilks, Regan G.; Zu, Fengshuo; Gutierrez‐Partida, Emilio; Iqbal, Zafar; Loghman Nia, Zahra; Yang, Fengjiu; Delli Veneri, Paola; Zhu, Kai; Stolterfoht, Martin; Bär, Marcus; Weber, Stefan A.; Schulz, Philip; Puel, Jean‐Baptiste; Kleider, Jean‐Paul; Unger, Eva; Wang, Qiong; Musiienko, Artem; Abate, AntonioInorganic perovskite CsPbI3 solar cells hold great potential for improving the operational stability of perovskite photovoltaics. However, electron extraction is limited by the low conductivity of TiO2, representing a bottleneck for achieving stable performance. In this study, a co‐doping strategy for TiO2 using Nb(V) and Sn(IV), which reduces the material's work function by 80 meV compared to Nb(V) mono‐doped TiO2, is introduced. To gain fundamental understanding of the processes at the interfaces between the perovskite and charge‐selective layer, transient surface photovoltage measurements are applied, revealing the beneficial effect of the energetic and structural modification on electron extraction across the CsPbI3/TiO2 interface. Using 2D drift‐diffusion simulations, it is found that co‐doping reduces the interface hole recombination velocity by two orders of magnitude, increasing the concentration of extracted electrons by 20%. When integrated into n-i-p solar cells, co‐doped TiO2 enhances the projected TS80 lifetimes under continuous AM1.5G illumination by a factor of 25 compared to mono‐doped TiO2. This study provides fundamental insights into interfacial charge extraction and its correlation with operational stability of perovskite solar cells, offering potential applications for other charge‐selective contacts.Item Open Access Physical interpretation of interwell partitioning tracer tests for estimation of remaining oil saturation in layered carbonate reservoirs(2025) Fontalvo, Samuel D.; Yutkin, Maxim P.; Hassanizadeh, S. Majid; Radke, Clayton J.; Patzek, Tadeusz W.Interwell partitioning tracer tests (IPTTs) are conducted in mature oil fields to estimate remaining oil in place, which is crucial for subsequent economic analyses and decisions regarding further field development. An IPTT involves the simultaneous injection of two types of tracers: conservative and partitioning, that probe the aqueous and oil phases, respectively. Although this test requires time, it probes the entire fluid flow path, not just the near-wellbore area, as is the case with other methods such as single-well tests. Accurate interpretation of interwell tracer test data is of critical importance for the oil and gas industry. Published IPTT case studies lack physical justification for the choice of tracer flow models. In this study, we provide such justifications along with guidelines for selecting appropriate tracer flow models. First, we review existing models for the transport of partitioning and conservative tracers and demonstrate their applicability range based on mass conservation analysis. Based on this analysis, we propose a refined model of partitioning tracer flow with Robin boundary conditions that accounts for non-equilibrium partitioning. Such analysis is missing in the literature. Next, we illustrate errors in estimating remaining oil if an inappropriate model is used for data interpretation. Notably, the choice of an incorrect model can lead to either underestimation or overestimation of the remaining oil, with the latter being of greater financial concern. Finally, we apply the non-equilibrium partitioning model to a published IPTT dataset from a layered carbonate reservoir and compare our remaining oil estimates with results of the original study. To the best of our knowledge, analysis of such cases with non-equilibrium partitioning has not been documented in the literature.Item Open Access Pressure-temperature-time evolution of a polymetamorphic paragneiss with pseudomorphs after jadeite from the HP-UHP gneiss‐eclogite unit of the Variscan Erzgebirge crystalline complex, Germany(2024) Massonne, Hans‐JoachimA quartz‐rich paragneiss from the Variscan Erzgebirge Crystalline Complex (ECC) was studied in detail because of abundant millimetre‐sized and clearly oriented pseudomorphs after a sodic mineral interpreted to have been jadeite. This mineral, or pseudomorphs after it, is rarely found in extensive high‐pressure (HP)-ultrahigh‐pressure (UHP) terranes worldwide despite reported pressure-temperature (P-T) conditions suitable for the formation of jadeite in common paragneisses and orthogneisses. In the studied rock, which contains abundant large and oriented potassic white mica flakes and minor millimetre‐sized garnet grains, the pseudomorphs consist of clusters of small albite grains with thin phengitic muscovite flakes in between. X‐ray maps for Ca and Mg in garnet demonstrate that an early generation of this mineral (Gt1) was corroded and subsequently overgrown by a Ca‐richer generation (Gt2). White mica is phengite with maximum Si contents of 3.42 atoms per formula unit. P-T conditions of 0.85 GPa and 650°C and 1.7 GPa and 660°C were derived for the formation of Gt1 and Gt2 rim + Si‐rich phengite, respectively, using pseudosection modelling. The latter conditions representing the pressure peak experienced by the paragneiss are compatible with the original presence of jadeite and possibly paragonite as well. This metamorphic peak occurred at 338.4 ± 2.3 (2σ) Ma based on in situ dating of monazite grains with the electron microprobe. A single monazite age of 386.4 ± 10.5 (2σ) Ma is related to the formation of Gt1. Thus, a Late Devonian metamorphism is suggested here for the first time to have occurred in ECC gneisses before the major HP event in the Early Carboniferous. Furthermore, the study demonstrates that the eclogite‐facies gneisses of the Gneiss‐Eclogite Unit of the ECC experienced peak pressures of not more than 2 GPa in contrast to recent proposals of an extensive UHP area in this unit. In addition, it is suggested that the localized occurrence of UHP rocks surrounded by other lithologies otherwise lacking evidence for UHP conditions should be interpreted with caution with respect to their regional extent and significance.Item Open Access Assessing advanced propulsion systems using the impact monitor framework(2025) Gupta, Utkarsh; Riaz, Atif; Brenner, Felix; Lefebvre, Thierry; Ratei, Patrick; Alder, Marko; Prakasha, Prajwal Shiva; Weber, Lukas; Pons-Prats, Jordi; Markatos, DionysiosPresented in this paper is the Impact Monitor framework and interactive Dashboard Application (DA) validated through a use case, focusing on investigating the viability and competitiveness of future propulsion architectures for next-generation aircraft concepts. This paper presents a novel collaborative framework for integrated aircraft-level assessments, focusing on secure, remote workflows that protect intellectual property (IP) while enabling comprehensive and automated analyses. The research addresses a key gap in the aerospace domain: the seamless matching and sizing of aircraft engines within an automated workflow that integrates multiple tools and facilitates real-time data exchanges. Specifically, thrust requirements are iteratively shared between aircraft and engine modeling environments for synchronized sizing. Subsequently, the fully defined aircraft data are transferred to other tools for trajectory analysis and emissions and other assessments. The Impact Monitor framework and Dashboard Application demonstrate improved efficiency and data security, promoting effective collaboration across institutions and industry partners.Item Open Access Exploring Phaeodactylum tricornutum for nutraceuticals : cultivation techniques and neurotoxin risk asssessment(2025) Ebbing, Tobias; Kopp, Lena; Frick, Konstantin; Simon, Tabea; Würtz, Berit; Pfannstiel, Jens; Schmid-Staiger, Ulrike; Bischoff, Stephan C.; Tovar, Günter E. M.This study investigates the potential of the diatom Phaeodactylum tricornutum (PT) as a sustainable and nutritionally valuable food source, focusing on its ability to produce bioactive compounds such as eicosapentaenoic acid, fucoxanthin, chrysolaminarin (CRY) and proteins. PT was cultivated in a flat-plate airlift photobioreactor (FPA-PBR) illuminated with LEDs from two sides. The study aimed to monitor and minimize β-methylamino-L-alanine (BMAA) levels to address safety concerns. The data showed that the selected FPA-PBR setup was superior in biomass and EPA productivity, and CRY production was reduced. No BMAA was detected in any biomass sample during cultivation. By adjusting the cultivation conditions, PT biomass with different compositional profiles could be produced, enabling various applications in the food and health industries. Biomass from nutrient-repleted conditions is rich in EPA and Fx, with nutritional and health benefits. Biomass from nutrient-depleted conditions accumulated CRY, which can be used as dietary fiber. These results highlight the potential of PT as a versatile ingredient for human consumption and the effectiveness of FPA-PBRs with artificial lighting in producing high-quality biomass. This study also provides the basis for future research to optimize photobioreactor conditions to increase production efficiency and to tailor the biomass profiles of PT for targeted health-promoting applications.Item Open Access Controlling grain boundary segregation to tune the conductivity of ceramic proton conductors(2024) Kindelmann, Moritz; Povstugar, Ivan; Kuffer, Severin; Jennings, Dylan; Ebert, Julian N.; Weber, Moritz Lukas; Zahler, Pascal; Escolastico, Sonia; Almar, Laura; Serra, Jose M.; Kaghazchi, Payam; Bram, Martin; Rheinheimer, Wolfgang; Mayer, Joachim; Guillon, OlivierAcceptor‐doped barium zirconates are of major interest as proton‐conducting ceramics for electrochemical applications at intermediate operating temperatures. However, the proton transport through polycrystalline microstructures is hindered by the presence of a positive space charge potential at grain boundaries. During high‐temperature sintering, the positive charge acts as a driving force for acceptor dopant segregation to the grain boundary. Acceptor segregation to grain boundaries has been observed in sintered ceramics, but the fundamental relationship between the segregation kinetics and the protonic conductivity is poorly understood. Here, a comprehensive study of the influence of acceptor dopant segregation on the electrochemical properties of grain boundaries in barium zirconate ceramics is presented. An out‐of‐equilibrium model material that displays no detectable Y segregation at its grain boundaries is explicitly designed. This model material serves as a starting point to measure the kinetics of segregation and the induced changes in grain boundary conductivity upon varying thermal histories. Furthermore, the electrochemical results from impedance spectroscopy to atomic resolution transmission electron microscopy, atom probe tomography, and DFT simulations are correlated. It is discovered that acceptor dopant segregation drastically increases the proton conductivity in both the model system and several other application‐relevant compositions.Item Open Access The impact of donor‐orientation on the emission properties of chlorinated trityl radicals(2025) Arnold, Mona E.; Toews, Robert; Schneider, Lars; Schmid, Jonas; Putra, Miftahussurur Hamidi; Busch, Michael; Groß, Axel; Deschler, Felix; Köhn, Andreas; Kuehne, Alexander J. C.Chlorinated trityl radicals functionalized with electron‐donating groups are promising red‐emitting materials for optoelectronic and spintronic applications, overcoming the spin‐statistical limit of conventional emitters. Donor functionalization induces charge transfer character, enhancing photoluminescence quantum yield, which depends on the donor strength and its orientation. However, donor‐functionalized tris(trichlorophenyl)methyl radicals often show lower quantum yield than their perchlorinated derivatives, likely due to weaker donor‐acceptor electronic coupling and enhanced non‐radiative decay. A novel trityl derivative is presented with two additional chlorines that restrict the orientation of the donor to a nearly perpendicular arrangement toward the trityl plane, minimizing vibronic coupling and non‐radiative losses. Spectroscopic and computational studies reveal that this steric constraint improves the photoluminescence quantum yield compared to the tris(trichlorophenyl)methyl analogs. These findings highlight the potential of donor‐acceptor decoupling to enable efficient, redshifted emission, offering a design strategy for high‐performance radical emitters.