@article{BernauKnoedlerEmontsetal.2022, author = {Bernau, C. R. and Kn{\"o}dler, Matthias and Emonts, Jessica and J{\"a}pel, Ronald Colin and Buyel, Johannes Felix}, title = {The use of predictive models to develop chromatography-based purification processes}, series = {Frontiers in Bioengineering and Biotechnology}, journal = {Frontiers in Bioengineering and Biotechnology}, number = {10}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2296-4185 (online-ressource)}, doi = {10.3389/fbioe.2022.1009102}, pages = {25 Seiten}, year = {2022}, abstract = {Chromatography is the workhorse of biopharmaceutical downstream processing because it can selectively enrich a target product while removing impurities from complex feed streams. This is achieved by exploiting differences in molecular properties, such as size, charge and hydrophobicity (alone or in different combinations). Accordingly, many parameters must be tested during process development in order to maximize product purity and recovery, including resin and ligand types, conductivity, pH, gradient profiles, and the sequence of separation operations. The number of possible experimental conditions quickly becomes unmanageable. Although the range of suitable conditions can be narrowed based on experience, the time and cost of the work remain high even when using high-throughput laboratory automation. In contrast, chromatography modeling using inexpensive, parallelized computer hardware can provide expert knowledge, predicting conditions that achieve high purity and efficient recovery. The prediction of suitable conditions in silico reduces the number of empirical tests required and provides in-depth process understanding, which is recommended by regulatory authorities. In this article, we discuss the benefits and specific challenges of chromatography modeling. We describe the experimental characterization of chromatography devices and settings prior to modeling, such as the determination of column porosity. We also consider the challenges that must be overcome when models are set up and calibrated, including the cross-validation and verification of data-driven and hybrid (combined data-driven and mechanistic) models. This review will therefore support researchers intending to establish a chromatography modeling workflow in their laboratory.}, language = {en} } @article{EmontsBuyel2023, author = {Emonts, Jessica and Buyel, Johannes Felix}, title = {An overview of descriptors to capture protein properties - Tools and perspectives in the context of QSAR modeling}, series = {Computational and Structural Biotechnology Journal}, journal = {Computational and Structural Biotechnology Journal}, number = {21}, publisher = {Research Network of Computational and Structural Biotechnology}, address = {Gotenburg}, issn = {2001-0370 (online-ressource)}, doi = {10.1016/j.csbj.2023.05.022}, pages = {3234 -- 3247}, year = {2023}, abstract = {Proteins are important ingredients in food and feed, they are the active components of many pharmaceutical products, and they are necessary, in the form of enzymes, for the success of many technical processes. However, production can be challenging, especially when using heterologous host cells such as bacteria to express and assemble recombinant mammalian proteins. The manufacturability of proteins can be hindered by low solubility, a tendency to aggregate, or inefficient purification. Tools such as in silico protein engineering and models that predict separation criteria can overcome these issues but usually require the complex shape and surface properties of proteins to be represented by a small number of quantitative numeric values known as descriptors, as similarly used to capture the features of small molecules. Here, we review the current status of protein descriptors, especially for application in quantitative structure activity relationship (QSAR) models. First, we describe the complexity of proteins and the properties that descriptors must accommodate. Then we introduce descriptors of shape and surface properties that quantify the global and local features of proteins. Finally, we highlight the current limitations of protein descriptors and propose strategies for the derivation of novel protein descriptors that are more informative.}, language = {en} } @phdthesis{Emonts2013, author = {Emonts, Jessica}, title = {Searching for many defective edges in hypergraphs}, publisher = {Rheinisch-Westf{\"a}lischen Technischen Hochschule Aachen}, address = {Aachen}, pages = {VIII, 104 Seiten : Ill.}, year = {2013}, language = {en} } @article{KnoedlerRuehlEmontsetal.2019, author = {Kn{\"o}dler, Matthias and R{\"u}hl, Clemens and Emonts, Jessica and Buyel, Johannes Felix}, title = {Seasonal weather changes affect the yield and quality of recombinant proteins produced in transgenic tobacco plants in a greenhouse setting}, series = {Frontiers in Plant Science}, journal = {Frontiers in Plant Science}, number = {10}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1664-462X (online-ressource)}, doi = {10.3389/fpls.2019.01245}, pages = {13 Seiten}, year = {2019}, abstract = {Transgenic plants have the potential to produce recombinant proteins on an agricultural scale, with yields of several tons per year. The cost-effectiveness of transgenic plants increases if simple cultivation facilities such as greenhouses can be used for production. In such a setting, we expressed a novel affinity ligand based on the fluorescent protein DsRed, which we used as a carrier for the linear epitope ELDKWA from the HIV-neutralizing antibody 2F5. The DsRed-2F5-epitope (DFE) fusion protein was produced in 12 consecutive batches of transgenic tobacco (Nicotiana tabacum) plants over the course of 2 years and was purified using a combination of blanching and immobilized metal-ion affinity chromatography (IMAC). The average purity after IMAC was 57 ± 26\% (n = 24) in terms of total soluble protein, but the average yield of pure DFE (12 mg kg-1) showed substantial variation (± 97 mg kg-1, n = 24) which correlated with seasonal changes. Specifically, we found that temperature peaks (>28°C) and intense illuminance (>45 klx h-1) were associated with lower DFE yields after purification, reflecting the loss of the epitope-containing C-terminus in up to 90\% of the product. Whereas the weather factors were of limited use to predict product yields of individual harvests conducted for each batch (spaced by 1 week), the average batch yields were well approximated by simple linear regression models using two independent variables for prediction (illuminance and plant age). Interestingly, accumulation levels determined by fluorescence analysis were not affected by weather conditions but positively correlated with plant age, suggesting that the product was still expressed at high levels, but the extreme conditions affected its stability, albeit still preserving the fluorophore function. The efficient production of intact recombinant proteins in plants may therefore require adequate climate control and shading in greenhouses or even cultivation in fully controlled indoor farms.}, language = {en} } @article{KaemperBergBegemannetal.1998, author = {K{\"a}mper, Klaus-Peter and Berg, U. and Begemann, M. and Hagemann, B.}, title = {Series production and testing of a micro motor. Serienfertigung und Pr{\"u}fung eines Mikromotors}, series = {Actuator 98 : 6th International Conference on New Actuators ; 17 - 19 June, 1998, Bremen, Germany ; conference proceedings / ed.: Hubert Borgmann ...}, journal = {Actuator 98 : 6th International Conference on New Actuators ; 17 - 19 June, 1998, Bremen, Germany ; conference proceedings / ed.: Hubert Borgmann ...}, publisher = {Messe Bremen}, address = {Bremen}, isbn = {3-933339-00-6}, pages = {552 -- 555}, year = {1998}, language = {en} } @incollection{FranzenSteckenPfaffetal.2019, author = {Franzen, Julian and Stecken, Jannis and Pfaff, Raphael and Kuhlenk{\"o}tter, Bernd}, title = {Using the Digital Shadow for a Prescriptive Optimization of Maintenance and Operation : The Locomotive in the Context of the Cyber-Physical System}, series = {Advances in Production, Logistics and Traffic}, booktitle = {Advances in Production, Logistics and Traffic}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-13535-5}, doi = {10.1007/978-3-030-13535-5_19}, pages = {265 -- 276}, year = {2019}, abstract = {In competition with other modes of transport, rail freight transport is looking for solutions to become more attractive. Short-term success can be achieved through the data-driven optimization of operations and maintenance as well as the application of novel strategies such as prescriptive maintenance. After introducing the concept of prescriptive maintenance, this paper aims to prove that vehicle-focused applications of this approach indeed have the potential to increase attractiveness. However, even greater advantages can be activated if data from the horizontal network of the vehicle is available. Drawing on the state of the art in research and technology in the field of cyber-physical systems (CPS) as well as digital twins and shadows, our work serves to design a system of systems for the horizontal interconnection of a rail vehicle and to conceptualize a draft for a digital twin of a locomotive.}, language = {en} } @article{PfaffSchmidtPinders2015, author = {Pfaff, Raphael and Schmidt, Bernd and Pinders, Udo}, title = {Energieeffizienz steigern durch Rekuperationseinrichtungen}, series = {Deine Bahn}, journal = {Deine Bahn}, number = {5}, publisher = {Eisenbahn-Fachverlag}, address = {Mainz}, issn = {0172-4479}, pages = {50 -- 53}, year = {2015}, language = {de} } @article{PfaffEnning2017, author = {Pfaff, Raphael and Enning, Manfred}, title = {Die nachhaltige Alternative zum autonomen Lastwagen}, series = {Deine Bahn}, journal = {Deine Bahn}, number = {10}, pages = {22 -- 26}, year = {2017}, language = {de} } @techreport{PfaffGeorgeSeileretal.2005, author = {Pfaff, Raphael and George, Alfred and Seiler, Friedrich and Srulijes, Julio}, title = {Dopplerbild-Verfahren : Entwicklung einer neuen Auswertemethode. (Bericht / ISL / AGARD ; R 124/2005)}, publisher = {ISL}, address = {Saint Louis, France}, pages = {X, 26 S. : Ill., graph. Darst.}, year = {2005}, language = {de} } @phdthesis{Pfaff2013, author = {Pfaff, Raphael}, title = {Evaluation and extension of the potential for application of the behavioural framework to practical engineering problems}, pages = {XVI, 231 S.}, year = {2013}, language = {en} } @article{Pfaff2023, author = {Pfaff, Raphael}, title = {Braking distance prediction for vehicle consist in low-speed on-sight operation: a Monte Carlo approach}, series = {Railway Engineering Science}, volume = {31}, journal = {Railway Engineering Science}, number = {2}, publisher = {SpringerOpen}, issn = {2662-4753 (eISSN)}, doi = {10.1007/s40534-023-00303-7}, pages = {135 -- 144}, year = {2023}, abstract = {The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive (e.g. in the case of depot operations) or highly inefficient (e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for low-speed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.}, language = {en} } @inproceedings{WilbringEnningPfaffetal.2019, author = {Wilbring, Daniela and Enning, Manfred and Pfaff, Raphael and Schmidt, Bernd}, title = {Neue Perspektiven f{\"u}r die Bahn in der Produktions- und Distributionslogistik durch Prozessautomation}, series = {IRSA 2019: Tagungsband, Proceedings}, booktitle = {IRSA 2019: Tagungsband, Proceedings}, editor = {de Doncker, Rik W. and Nießen, Nils and Schindler, Christian}, publisher = {RWTH Aachen}, address = {Aachen}, doi = {10.18154/RWTH-2020-00014}, pages = {128 -- 142}, year = {2019}, abstract = {Deutschland braucht mehr Eisenbahn um CO2-Emissionen aus dem Verkehr zu reduzieren. Sie muss zum R{\"u}ckgrat aktueller Logistikprozesse, z.B. bei Kaufmannsg{\"u}tern und E-Commerce, werden. Dies geht nicht ohne neuartige betriebliche Konzepte und eine Transformation des G{\"u}terwagens von einem „dummen St{\"u}ck Stahl" zu einem modernen Werkzeug der Logistik. Als „G{\"u}terwagen 4.0" wird ein kommunikativer und kooperativer G{\"u}terwagen verstanden, der die Voraussetzung zur Automatisierung aller Prozesse der Zugvorbereitung bereitstellt, sich aber ansonsten vollkommen kompatibel mit heutigen Betriebsverfahren im Hauptlauf pr{\"a}sentiert. Durch Kommunikation zwischen G{\"u}terwagen und umgebenden intelligenten Systemen im Sinne eines „Internet der Dinge" gelingt damit unter Anderem die Realisierung hoch effizienter Gleisanschlussverkehre, die der G{\"u}terbahn neue M{\"a}rkte abseits der klassisch bahn-affinen Verkehre erschließen und letztlich den Wandel zu einer nachhaltigen G{\"u}termobilit{\"a}t f{\"o}rdern.}, language = {de} } @article{WilbringEnningPfaffetal.2020, author = {Wilbring, Daniela and Enning, Manfred and Pfaff, Raphael and Schmidt, Bernd}, title = {Neue Perspektiven f{\"u}r die Bahn in der Produktions- und Distributionslogistik durch Prozessautomation}, series = {ETR - Eisenbahntechnische Rundschau}, volume = {69}, journal = {ETR - Eisenbahntechnische Rundschau}, number = {3}, publisher = {DVV Mediagroup}, address = {Hamburg}, issn = {0013-2845}, pages = {15 -- 19}, year = {2020}, language = {de} } @inproceedings{PfaffShahidiEnning2017, author = {Pfaff, Raphael and Shahidi, Parham and Enning, Manfred}, title = {Connected freight rail rolling stock: a modular approach integrating sensors, actors and cyber physical systems for operational advantages and condition based maintenance}, series = {Asia-Pacific Conference of the Prognostics and Health Management Society}, booktitle = {Asia-Pacific Conference of the Prognostics and Health Management Society}, pages = {1 -- 7}, year = {2017}, language = {en} } @inproceedings{SeilerGeorgePfaffetal.2005, author = {Seiler, Friedrich and George, Alfred and Pfaff, Raphael and Srulijes, Julio}, title = {Stand der Entwicklung des ISL Dopplerbildverfahrens}, series = {GALA : 13. Fachtagung Lasermethoden in der Str{\"o}mungsmesstechnik : 6. - 8. September 2005, Cottbus}, booktitle = {GALA : 13. Fachtagung Lasermethoden in der Str{\"o}mungsmesstechnik : 6. - 8. September 2005, Cottbus}, publisher = {Techn. Univ.}, address = {Cottbus}, organization = {Fachtagung Lasermethoden in der Str{\"o}mungsmesstechnik <13, 2005, Cottbus>}, isbn = {3-9805613-2-1}, pages = {24-1 -- 24-8}, year = {2005}, language = {de} } @inproceedings{PfaffPichlerGeorgeetal.2007, author = {Pfaff, Raphael and Pichler, Alexander and George, Alfred and Seiler, Friedrich}, title = {Model based image processing for flow visualisation : 16th International Conference on Systems Science, Wroclaw, Poland, September 04 - 06, 2007}, series = {PU / Institut Franco-Allemand de Recherches de Saint-Louis ; 2007, 620}, booktitle = {PU / Institut Franco-Allemand de Recherches de Saint-Louis ; 2007, 620}, publisher = {ISL}, address = {Saint Louis, France}, organization = {International Conference on Systems Science <16, 2007, Wroclaw>}, pages = {1 -- 10}, year = {2007}, language = {en} } @inproceedings{Pfaff2017, author = {Pfaff, Raphael}, title = {Analysis of Big Data Streams to obtain Braking Reliability Information for Train Protection systems}, series = {Asia-Pacific Conference of the Prognostics and Health Management Society}, booktitle = {Asia-Pacific Conference of the Prognostics and Health Management Society}, pages = {1 -- 7}, year = {2017}, language = {en} } @inproceedings{GaoBabilonPfaffetal.2018, author = {Gao, H. and Babilon, Katharina and Pfaff, Raphael and Gan, F. and Reich, A.}, title = {Model of wheel-rail contact for sanding and adhesion enhancement}, series = {Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018}, booktitle = {Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018}, isbn = {978-946186963-0}, pages = {314 -- 321}, year = {2018}, language = {en} } @inproceedings{SeilerPichlerPfaffetal.2008, author = {Seiler, Friedrich and Pichler, Alexander and Pfaff, Raphael and George, Alfred and Srulijes, Julio}, title = {Improved Doppler picture velocimetry and new automated processing}, series = {14th International Symposium on Applications of Laser Techniques to Fluid Mechanics : Lisbon, Portugal, 7 - 10 July 2008}, booktitle = {14th International Symposium on Applications of Laser Techniques to Fluid Mechanics : Lisbon, Portugal, 7 - 10 July 2008}, organization = {International Symposium on Applications of Laser Techniques to Fluid Mechanics <14, 2008, Lisboa>}, pages = {1 -- 12}, year = {2008}, language = {en} } @article{EnningPfaff2017, author = {Enning, Manfred and Pfaff, Raphael}, title = {G{\"u}terwagen 4.0 - Der G{\"u}terwagen f{\"u}r das Internet der Dinge. Teil 1: Gesamtsystembetrachtung und grundlegendes Konzept}, series = {ETR - Eisenbahntechnische Rundschau}, volume = {66}, journal = {ETR - Eisenbahntechnische Rundschau}, number = {1/2}, publisher = {DVV Media Group}, address = {Hamburg}, issn = {0013-2845}, pages = {12 -- 16}, year = {2017}, language = {de} }