Fakultät Maschinenbau und Verfahrenstechnik (M+V)
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Peptidyl-lys metalloendopeptidases (PKMs) are enzymes that selectively cleave peptide bonds at the N-terminus of lysine residues present in the P1′ position, making them valuable tools in proteomics. This mini-review presents an overview of PKMs, covering their traditional production from native sources, recent advances in recombinant production, and the current limitations in availability. The historical and current applications of PKMs in proteomics are discussed, highlighting their role in protein sequencing, peptide mapping, and mass spectrometry-based studies. Advances in recombinant technology now enable tailored modifications to PKM, allowing it to function not only as a sister enzyme to LysC but also to trypsin, thereby enhancing its suitability for specific analytical applications. The mini-review concludes with a forward-looking statement on PKM research, emphasizing the potential to broaden its use in novel proteomic methods and other applications.
This thesis investigates the use of Artificial Intelligence (AI) models for predicting the performance characteristics of compressors, with a focus on centrifugal configurations. Using a dataset of 27 compressor samples manually extracted from academic literature, and further expanded through data augmentation. The study evaluates the predictive capabilities of three regression models: Random Forest, XGBoost, and Multi-Layer Perceptron (MLP). The models were trained to predict multiple compressor attributes, including choke and surge points for pressure ratio and mass flow rates and other geometric features, based on input design parameters.
Advanced data preprocessing techniques, such as multiple imputation and feature scaling, were applied to improve model performance. A data augmentation strategy was also implemented to address the dataset’s limited size. Model evaluation was conducted using Mean Absolute Error (MAE) and R-squared (R²) metrics.
The results indicate that XGBoost consistently outperformed the other models across most target features, especially after data augmentation, achieving R² scores above 0.9 for several outputs. Random Forest also delivered robust results, particularly in predicting isentropic efficiency and blade geometry. MLP showed poor performance across all scenarios, highlighting the challenges of applying deep learning to small, structured datasets.
The study concludes that tree-based ensemble methods, particularly XGBoost, are well-suited for compressor performance prediction. The work also emphasizes the importance of data augmentation and preprocessing in enhancing model generalization. Despite limitations due to data scarcity, the findings demonstrate the viability of AI models as effective tools for compressor analysis and design optimization.
Redox-active biochars can enhance contaminant transformation in persulfate-based Fenton-like water treatment by facilitating Fe(III) reduction to Fe(II). However, biochar properties vary greatly depending on both feedstock selection and pyrolysis conditions. Best suited biochars for Fe(III) reduction and persulfate activation have yet to be identified. Here, we investigated eight biochars for their ability to activate persulfate with Fe(III) to transform N,N-diethyl-m-toluamide (DEET) in water. Four of the biochars were produced from beech wood under different pyrolysis conditions (450–750 °C, high and low nitrogen flow rate in the reactor) and four biochars were produced from softwood amended with 0 – 43 weight percent (wt%) wood ash prior to pyrolysis at 500 °C. Beech wood biochar produced at 450 °C transformed DEET most efficiently with a half-life time of 39 ± 4 min, likely due to the high concentration of surface oxygen functional groups and persistent free radicals that accelerated Fe(III) reduction and formation of reactive species. Among the ash-amended biochars, biochar with 16 wt% ash amendment showed the most efficient DEET transformation with a half-life time of 27 ± 0.6 min, which is 10-times faster compared to a non-ash-amended biochar produced from the same biomass under similar pyrolysis conditions. Ash amendment led to the formation of crystalline iron minerals in biochars, which likely promoted Fe(III) reduction and persulfate activation. Our results highlight the potential for fine-tuning the redox properties of biochar, e.g., by ash amendment to a woody feedstock, enabling tailored performance for specific water treatment applications.
4D-Druck bezeichnet das Verfahren der Herstellung von Bauteilen, die als Reaktion auf äußere Reize ihre Struktur verändern. Diese Reaktion wird als Ausgangssignal als Folge auf ein Eingangssignal betrachtet. Ein mögliches Eingangssignal ist ein Magnetfeld mit einer bestimmten Orientierung und einem bestimmten Betrag. Ein solches Verhalten zeigen magnetresponsive Werkstoffe. Auf diese Weise lassen sich Handhabungsaufgaben, wie das Greifen von Objekten, lösen. Die Neuheit daran ist der Verzicht auf konventionelle Antriebe wie elektromechanische oder hydraulische Motoren.
Diese Arbeit erschließt das nötige Hintergrundwissen zu Magnetismus und soft robots. Der experimentelle Teil befasst sich mit der Herstellung eines magnetresponsiven Werkstoffes und der Entwicklung eines soft grippers. Es werden die 3D-Druckverfahren FDM und PAM mit magnetresponsivem Material verglichen. Ersteres ermöglicht ein Verarbeiten von Filament und letzteres von Granulat. Es zeigt sich, dass sich die Resultate in Hinblick auf Maßtreue und Elastizität unterscheiden, wobei das FDM-Verfahren besser abschneidet.
Die strukturierte Formgebung eines Greifers (soft gripper) wird erforscht. Dabei wird die Herstellbarkeit und die Bionik des Greifens vereint. Die externe Manipulierbarkeit ermöglicht einen Einsatz von soft grippern in kleinen Anwendungsgebieten wie minimal-invasiven Operationen mit einer Steuerung des Werkzeuges von außen.
Weiter wird ein Vorgehen zur Programmierung und Aktivierung der 4D-Druckteile entwickelt und vorgeschlagen. Dabei wird das Programmieren mittels zweier Permanentmagnete und das Aktivieren über eine Helmholtzspule realisiert. Die Helmholtzspule erzeugt ein homogenes steuerbares Magnetfeld.
Eine Verfahren zur analytischen Berechnung des benötigten magnetischen Feldes zur Aktivierung wird entwickelt und im letzten Kapitel vorgestellt.
The research for plastic alternatives is one of the most important recent fields in organic and polymer chemistry, aiming to develop novel materials for a more sustainable future. As humans impact even the most remote places on earth, pollution due to the accumulation of synthetic polymers is the witness of this devastating dynamic. However, promising biomass derived polymers have been discovered, showing the potential to replace fossil-based plastics efficiently. Nevertheless, only a small number of bio-based materials having comparable properties with their petrol-based counterparts are available nowadays. Intending to enlarge the knowledge on the possible renewable, recyclable, and/or biodegradable polymer materials, developing alternative methods and synthetic routes are indispensable. The chemo-enzymatic synthesis of polymers derived from itaconic acid (IA) represents a novel route amongst the various possible alternative paths of polymer synthesis and production. IA and its diester, dimethyl itaconate (DMI), have received a lot of interest as a new chemical building block since it is biotechnologically generated from carbohydrates on a large scale. Their trifunctional structures enable the production of novel polymers such as poly(itaconates), related copolymers, and derived monomers for polycondensation such as the herein described bispyrrolidone (BP) structures, dimethyl 2-((diethylamino)methyl)succinate (DAMS) and dimethyl 2-((octylthio)methyl)succinate (DOMS). This thesis elucidates, for the first time, the use of BP and DOMS as monomers for enzymatically catalyzed polymerization reactions. Novel BP monomers were prepared from reactions between renewable DMI and various aliphatic diamines. These BP monomers were synthesized with high conversions and purity showing versatility as monomer for polycondensation and as plasticizing additives in polymer blends with poly(lactic acid) (PLA). In particular, the monomers and new polyesters obtained by their polycondensation demonstrated remarkable thermal stability. Being a rather new field of research, polyesters generated from unsaturated acids like IA have only just begun to receive attention, despite a wide range of possible uses, including UV-curing resins for coatings, inks or adhesives, and thermally curing compositions, to mention a few. Establishing ecofriendly synthesis routes, combining the various tools available and theoretical organic chemistry, is an important step to allow the development of more sustainable synthesis and work-up procedures in the polymer industry. Within this project, further investigation into the synthesis and the potential of itaconate-based polyesters is described. The BP monomers synthesis and polymerization (using an immobilized enzyme) creating novel bio-based polyesters is particularly highlighted.
The focus of the present work was the investigation of dimensional stability in 3D printing with mycelium-based materials. This material composite is made of wood fibers that are bound by mycelium growth. Hemp and coconut fibers were examined as materials for 3D-printing in order to evaluate their suitability for this purpose. In order for the material to be used for 3D-printing, binders and water must be added to make the ink extrudable. Different compositions of the printing paste were produced and the loss of shape after 3D-printing and after heat inactivation was compared. The results of the study showed that, compared to hemp fibers, coconut fibers effectively regulate moisture during cultivation. However, increased shrinkage was observed during heat inactivation due to the higher water content.