@article{LuftBalcBremen2024, author = {Luft, Angela and Balc, Nicolae and Bremen, Sebastian}, title = {Experts' perspectives on the adoption of additive manufacturing in the industry and its interrelated implications in production structures}, series = {Acta Technica Napocensis}, volume = {67}, journal = {Acta Technica Napocensis}, number = {1s}, publisher = {Technical University of Cluj-Napoca}, address = {Cluj-Napoca}, issn = {1221-5872}, pages = {159 -- 168}, year = {2024}, abstract = {Additive Manufacturing (AM) is a topic that is becoming more relevant to many companies globally. With AM's progressive development and use for series production, integrating the technology into existing production structures is becoming an important criterion for businesses. This study qualitatively examines the actual state and different perspectives on the integration of AM in production structures. Seven semi-structured interviews were conducted and analyzed. The interview partners were high-level experts in Additive Manufacturing and production systems from industry and science. Four main themes were identified. Key findings are the far-reaching interrelationships and implications of AM within production structures. Specific AM-related aspects were identified. Those can be used to increase the knowledge and practical application of the technology in the industry and as a foundation for economic considerations.}, language = {en} } @article{LuftArntz2024, author = {Luft, Nils and Arntz, Kristian}, title = {The impact and challenges of Industry 4.0 on factory design, organization and management}, series = {Acta Technica Napocensis}, volume = {67}, journal = {Acta Technica Napocensis}, number = {1s}, publisher = {Technical University of Cluj-Napoca}, address = {Cluj-Napoca}, issn = {1221-5872}, pages = {151 -- 158}, year = {2024}, abstract = {The fourth industrial revolution is on its way to reshape manufacturing and value creation in a profound way. The underlying technologies like cyber-physical systems (CPS), big data, collaborative robotics, additive manufacturing or artificial intelligence offer huge potentials for the optimization and evolution of production systems. However, many manufacturing companies struggle to implement these technologies. This can only in part be attributed to the lack of skilled personal within these companies or a missing digitalization strategy. Rather, there is a fundamental incompatibility between the way current production systems and companies (Industry 3.0) are structured across multiple dimensions compared to what is necessary for industry 4.0. This is especially true in manufacturing systems and their transition towards flexible, decentralized and autonomous value creation networks. This paper shows across various dimensions these incompatibilities within manufacturing systems, explores their reasons and discusses a different approach to create a foundation for Industry 4.0 in manufacturing companies.}, language = {en} } @article{AbbasBalcBremenetal.2024, author = {Abbas, Karim and Balc, Nicolae and Bremen, Sebastian and Hedwig, Lukas}, title = {Polyetheretherketone (PEEK) in rapid tooling: advancements and applications for fused filament fabrication of rubber molds}, series = {Acta Technica Napocensis}, volume = {67}, journal = {Acta Technica Napocensis}, number = {1s}, publisher = {Technical University of Cluj-Napoca}, address = {Cluj-Napoca}, issn = {1221-5872}, pages = {13 -- 22}, year = {2024}, abstract = {Establishing high-performance polymers in additive manufacturing opens up new industrial applications. Polyetheretherketone (PEEK) was initially used in aerospace but is now widely applied in automotive, electronics, and medical industries. This study focuses on developing applications using PEEK and Fused Filament Fabrication for cost-efficient vulcanization injection mold production. A proof of concept confirms PEEK's suitability for AM mold making, withstanding vulcanization conditions. Printing PEEK above its glass transition temperature of 145 °C is preferable due to its narrow process window. A new process strategy at room temperature is discussed, with micrographs showing improved inter-layer bonding at 410°C nozzle temperature and 0.1 mm layer thickness. Minimizing the layer thickness from 0.15 mm to 0.1 mm improves tensile strength by 16\%.}, language = {en} } @article{EichlerBalcBremenetal.2024, author = {Eichler, Fabian and Balc, Nicolae and Bremen, Sebastian and Schleser, Markus and Schwarz, Alexander}, title = {Research on reducing residual stresses of SLM parts made for downstream welding process}, series = {Acta Technica Napocensis}, volume = {67}, journal = {Acta Technica Napocensis}, number = {1s}, publisher = {Technical University of Cluj-Napoca}, address = {Cluj-Napoca}, issn = {1221-5872}, pages = {69 -- 78}, year = {2024}, abstract = {In the face of the current trend towards larger and more complex production tasks in the SLM process and the current limitations in terms of maximum build space, the welding of SLM components to each other or to conventionally manufactured parts is becoming increasingly relevant. The fusion welding of SLM components made of 316L has so far been rarely investigated and if so, then for highly specialised laser welding processes. When welding with industrial gas welding processes such as MIG/MAG or TIG welding, distortions occur which are associated with the resulting residual stresses in the components. This paper investigates process-side influencing factors to avoid resulting residual stresses in SLM components made of 316L. The aim is to develop a strategy to build up SLM components as stress-free as possible in order to join them as profitably as possible with a downstream welding process. For this purpose, influencing parameters such as laser power, scan speed, but also scan vector length and different scan patterns are investigated with regard to their influence on residual stresses.}, language = {en} } @article{ValeroFelderKrameretal.2024, author = {Valero, Daniel and Felder, Stefan and Kramer, Matthias and Wang, Hang and Carrillo, Jos{\´e} M. and Pfister, Michael and Bung, Daniel}, title = {Air-water flows}, series = {Journal of Hydraulic Research}, volume = {62}, journal = {Journal of Hydraulic Research}, number = {4}, publisher = {Taylor \& Francis}, issn = {0022-1686 (Print)}, doi = {10.1080/00221686.2024.2379482}, pages = {319 -- 339}, year = {2024}, abstract = {High Froude-number open-channel flows can entrain significant volumes of air, a phenomenon that occurs continuously in spillways, in free-falling jets and in hydraulic jumps, or as localized events, notably at the toe of hydraulic jumps or in plunging jets. Within these flows, turbulence generates millions of bubbles and droplets as well as highly distorted wavy air-water interfaces. This phenomenon is crucial from a design perspective, as it influences the behaviour of high-velocity flows, potentially impairing the safety of dam operations. This review examines recent scientific and engineering progress, highlighting foundational studies and emerging developments. Notable advances have been achieved in the past decades through improved sampling of flows and the development of physics-based models. Current challenges are also identified for instrumentation, numerical modelling and (up)scaling that hinder the formulation of fundamental theories, which are instrumental for improving predictive models, able to offer robust support for the design of large hydraulic structures at prototype scale.}, language = {en} } @article{MyburghJacobszBothaLeRouxKotliaretal.2024, author = {Myburgh-Jacobsz, Catharina Elizabeth and Botha-Le Roux, Shani and Kotliar, Konstantin and Wentzel, Annemarie and Jacobs, Adriaan and De Boever, Patrick and Goswami, Nandu and Strijdom, Hans and Smith, Wayne}, title = {Retinal vessel functional responses in South Africans living with and without HIV: the EndoAfrica-NWU study}, series = {Microcirculation}, journal = {Microcirculation}, number = {Early View}, publisher = {Wiley}, address = {Malden, MA}, issn = {1073-9688 (Print)}, doi = {10.1111/micc.12878}, pages = {11 Seiten}, year = {2024}, language = {en} } @article{FreyerKemptKloeser2024, author = {Freyer, Nils and Kempt, Hendrik and Kl{\"o}ser, Lars}, title = {Easy-read and large language models: on the ethical dimensions of LLM-based text simplification}, series = {Ethics and Information Technology}, volume = {26}, journal = {Ethics and Information Technology}, publisher = {Springer}, address = {Dortrecht}, issn = {1388-1957 (Print)}, doi = {10.1007/s10676-024-09792-4}, pages = {10 Seiten}, year = {2024}, abstract = {The production of easy-read and plain language is a challenging task, requiring well-educated experts to write context-dependent simplifications of texts. Therefore, the domain of easy-read and plain language is currently restricted to the bare minimum of necessary information. Thus, even though there is a tendency to broaden the domain of easy-read and plain language, the inaccessibility of a significant amount of textual information excludes the target audience from partaking or entertainment and restricts their ability to live life autonomously. Large language models can solve a vast variety of natural language tasks, including the simplification of standard language texts to easy-read or plain language. Moreover, with the rise of generative models like GPT, easy-read and plain language may be applicable to all kinds of natural language texts, making formerly inaccessible information accessible to marginalized groups like, a.o., non-native speakers, and people with mental disabilities. In this paper, we argue for the feasibility of text simplification and generation in that context, outline the ethical dimensions, and discuss the implications for researchers in the field of ethics and computer science.}, language = {en} } @article{AkimbekovDigelZhubanovaetal.2024, author = {Akimbekov, Nuraly and Digel, Ilya and Zhubanova, Azhar and Tastambek, Kuanysh T. and Tepecik, Atakan and Sherelkhan, Dinara}, title = {Biotechnological potentials of surfactants in coal utilization: a review}, series = {Environmental Science and Pollution Research}, volume = {31}, journal = {Environmental Science and Pollution Research}, publisher = {Springer}, address = {Berlin}, issn = {1614-7499}, doi = {10.1007/s11356-024-34892-5}, pages = {55099 -- 55118}, year = {2024}, abstract = {The quest for scientifically advanced and sustainable solutions is driven by growing environmental and economic issues associated with coal mining, processing, and utilization. Consequently, within the coal industry, there is a growing recognition of the potential of microbial applications in fostering innovative technologies. Microbial-based coal solubilization, coal beneficiation, and coal dust suppression are green alternatives to traditional thermochemical and leaching technologies and better meet the need for ecologically sound and economically viable choices. Surfactant-mediated approaches have emerged as powerful tools for modeling, simulation, and optimization of coal-microbial systems and continue to gain prominence in clean coal fuel production, particularly in microbiological co-processing, conversion, and beneficiation. Surfactants (surface-active agents) are amphiphilic compounds that can reduce surface tension and enhance the solubility of hydrophobic molecules. A wide range of surfactant properties can be achieved by either directly influencing microbial growth factors, stimulants, and substrates or indirectly serving as frothers, collectors, and modifiers in the processing and utilization of coal. This review highlights the significant biotechnological potential of surfactants by providing a thorough overview of their involvement in coal biodegradation, bioprocessing, and biobeneficiation, acknowledging their importance as crucial steps in coal consumption.}, language = {en} } @article{AdelsThoennessenMonakhova2024, author = {Adels, Klaudia and Th{\"o}nnessen, Vera and Monakhova, Yulia}, title = {Complementary instrumental techniques applied to pain relieving tablets in an undergraduate laboratory experiment}, series = {Journal of Chemical Education}, journal = {Journal of Chemical Education}, publisher = {ACS}, issn = {0021-9584 (Print)}, doi = {10.1021/acs.jchemed.4c00681}, pages = {11 Seiten}, year = {2024}, abstract = {Several unconnected laboratory experiments are usually offered for students in instrumental analysis lab. To give the students a more rational overview of the most common instrumental techniques, a new laboratory experiment was developed. Marketed pain relief drugs, familiar consumer products with one to three active components, namely, acetaminophen (paracetamol), acetylsalicylic acid (ASA), and caffeine, were selected. Common analytical methods were compared regarding the performance of qualitative and quantitative analysis of unknown tablets: UV-visible (UV-vis), infrared (IR), and nuclear magnetic resonance (NMR) spectroscopies, as well as high-performance liquid chromatography (HPLC). The students successfully uncovered the composition of formulations, which were divided into three difficulty categories. Students were shown that in addition to simple mixtures handled in theoretical classes, the composition of complex drug products can also be uncovered. By comparing the performance of different techniques, students deepen their understanding and compare the efficiency of analytical methods in the context of complex mixtures. The laboratory experiment can be adjusted for graduate level by including extra tasks such as method optimization, validation, and 2D spectroscopic techniques.}, language = {en} } @article{SanchezCespedesLeasureTejedorGaravitoetal.2023, author = {Sanchez-Cespedes, Lina Maria and Leasure, Douglas Ryan and Tejedor-Garavito, Natalia and Amaya Cruz, Glenn Harry and Garcia Velez, Gustavo Adolfo and Mendoza Beltr{\´a}n, Andryu Enrique and Mar{\´i}n-Salazar, Yenny Andrea and Esch, Thomas and Tatem, Andrew J. and Ospina Boh{\´o}rquez, Mariana Francisca}, title = {Social cartography and satellite-derived building coverage for post-census population estimates in difficult-to-access regions of Colombia}, series = {Population studies : a Journal of Demography}, volume = {78}, journal = {Population studies : a Journal of Demography}, number = {1}, publisher = {Taylor \& Francis}, address = {London}, issn = {1477-4747}, doi = {10.1080/00324728.2023.2190151}, pages = {3 -- 20}, year = {2023}, abstract = {Effective government services rely on accurate population numbers to allocate resources. In Colombia and globally, census enumeration is challenging in remote regions and where armed conflict is occurring. During census preparations, the Colombian National Administrative Department of Statistics conducted social cartography workshops, where community representatives estimated numbers of dwellings and people throughout their regions. We repurposed this information, combining it with remotely sensed buildings data and other geospatial data. To estimate building counts and population sizes, we developed hierarchical Bayesian models, trained using nearby full-coverage census enumerations and assessed using 10-fold cross-validation. We compared models to assess the relative contributions of community knowledge, remotely sensed buildings, and their combination to model fit. The Community model was unbiased but imprecise; the Satellite model was more precise but biased; and the Combination model was best for overall accuracy. Results reaffirmed the power of remotely sensed buildings data for population estimation and highlighted the value of incorporating local knowledge.}, language = {en} } @article{VarrialeHengsbachGuoetal.2024, author = {Varriale, Ludovica and Hengsbach, Jan-Niklas and Guo, Tianyi and Kuka, Katrin and Tippk{\"o}tter, Nils and Ulber, Roland}, title = {Sustainable production of lactic acid using a perennial ryegrass as feedstock—a comparative study of fermentation at the bench- and reactor-scale, and ensiling}, series = {Sustainability}, volume = {16}, journal = {Sustainability}, number = {18}, publisher = {MDPI}, address = {Basel}, issn = {2071-1050}, doi = {10.3390/su16188054}, year = {2024}, abstract = {Perennial ryegrass (Lolium perenne) is an underutilized lignocellulosic biomass that has several benefits such as high availability, renewability, and biomass yield. The grass press-juice obtained from the mechanical pretreatment can be used for the bio-based production of chemicals. Lactic acid is a platform chemical that has attracted consideration due to its broad area of applications. For this reason, the more sustainable production of lactic acid is expected to increase. In this work, lactic acid was produced using complex medium at the bench- and reactor scale, and the results were compared to those obtained using an optimized press-juice medium. Bench-scale fermentations were carried out in a pH-control system and lactic acid production reached approximately 21.84 ± 0.95 g/L in complex medium, and 26.61 ± 1.2 g/L in press-juice medium. In the bioreactor, the production yield was 0.91 ± 0.07 g/g, corresponding to a 1.4-fold increase with respect to the complex medium with fructose. As a comparison to the traditional ensiling process, the ensiling of whole grass fractions of different varieties harvested in summer and autumn was performed. Ensiling showed variations in lactic acid yields, with a yield up to 15.2\% dry mass for the late-harvested samples, surpassing typical silage yields of 6-10\% dry mass.}, language = {en} } @article{OrtnerHauserSchmadereretal.2019, author = {Ortner, Marion and Hauser, Christine and Schmaderer, Christoph and Muggenthaler, Claudia and Hapfelmeier, Alexander and Sorg, Christian and Diehl-Schmid, Janine and Kurz, Alexander and F{\"o}rstl, Hans and Ikenberg, Benno and Kotliar, Konstantin and Holger, Poppert and Grimmer, Timo}, title = {Decreased vascular pulsatility in Alzheimer's disease dementia measured by transcranial color-coded duplex sonography}, series = {Neuropsychiatric disease and treatment}, journal = {Neuropsychiatric disease and treatment}, number = {15}, publisher = {Dove Medical Press}, address = {Albany, Auckland}, issn = {1178-2021}, doi = {10.2147/NDT.S225754}, pages = {3487 -- 3499}, year = {2019}, abstract = {Purpose: Impaired paravascular drainage of β-Amyloid (Aβ) has been proposed as a contributing cause for sporadic Alzheimer's disease (AD), as decreased cerebral blood vessel pulsatility and subsequently reduced propulsion in this pathway could lead to the accumulation and deposition of Aβ in the brain. Therefore, we hypothesized that there is an increased impairment in pulsatility across AD spectrum. Patients and Methods: Using transcranial color-coded duplex sonography (TCCS) the resistance and pulsatility index (RI; PI) of the middle cerebral artery (MCA) in healthy controls (HC, n=14) and patients with AD dementia (ADD, n=12) were measured. In a second step, we extended the sample by adding patients with mild cognitive impairment (MCI) stratified by the presence (MCI-AD, n=8) or absence of biomarkers (MCI-nonAD, n=8) indicative for underlying AD pathology, and compared RI and PI across the groups. To control for atherosclerosis as a confounder, we measured the arteriolar-venular-ratio of retinal vessels. Results: Left and right RI (p=0.020; p=0.027) and left PI (p=0.034) differed between HC and ADD controlled for atherosclerosis with AUCs of 0.776, 0.763, and 0.718, respectively. The RI and PI of MCI-AD tended towards ADD, of MCI-nonAD towards HC, respectively. RIs and PIs were associated with disease severity (p=0.010, p=0.023). Conclusion: Our results strengthen the hypothesis that impaired pulsatility could cause impaired amyloid clearance from the brain and thereby might contribute to the development of AD. However, further studies considering other factors possibly influencing amyloid clearance as well as larger sample sizes are needed.}, language = {en} } @article{BandlitzNakhoulKotliar2022, author = {Bandlitz, Stefan and Nakhoul, Makram and Kotliar, Konstantin}, title = {Daily variations of corneal white-to-white diameter measured with different methods}, series = {Clinical and experimental optometry}, journal = {Clinical and experimental optometry}, number = {14}, publisher = {Taylor \& Francis}, address = {London}, issn = {0816-4622}, doi = {10.2147/OPTO.S360651}, pages = {173 -- 181}, year = {2022}, abstract = {Purpose: A precise determination of the corneal diameter is essential for the diagnosis of various ocular diseases, cataract and refractive surgery as well as for the selection and fitting of contact lenses. The aim of this study was to investigate the agreement between two automatic and one manual method for corneal diameter determination and to evaluate possible diurnal variations in corneal diameter. Patients and Methods: Horizontal white-to-white corneal diameter of 20 volunteers was measured at three different fixed times of a day with three methods: Scheimpflug method (Pentacam HR, Oculus), placido based topography (Keratograph 5M, Oculus) and manual method using an image analysis software at a slitlamp (BQ900, Haag-Streit). Results: The two-factorial analysis of variance could not show a significant effect of the different instruments (p = 0.117), the different time points (p = 0.506) and the interaction between instrument and time point (p = 0.182). Very good repeatability (intraclass correlation coefficient ICC, quartile coefficient of dispersion QCD) was found for all three devices. However, manual slitlamp measurements showed a higher QCD than the automatic measurements with the Keratograph 5M and the Pentacam HR at all measurement times. Conclusion: The manual and automated methods used in the study to determine corneal diameter showed good agreement and repeatability. No significant diurnal variations of corneal diameter were observed during the period of time studied.}, 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{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} } @article{RieplPettrakFaulstichetal.2010, author = {Riepl, Herbert Matthias and Pettrak, J{\"u}rgen and Faulstich, Martin and Herrmann, Wolfgang Anton}, title = {Self metathesis of fatty alcohols and amines to provide monomers for polyester and polyamide products}, series = {Macromolecular Symposia}, volume = {293}, journal = {Macromolecular Symposia}, number = {1}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-3900 (eISSN)}, doi = {10.1002/masy.200900041}, pages = {39 -- 42}, year = {2010}, abstract = {Self metathesis of oleochemicals offers a variety of bifunctional compounds, that can be used as monomer for polymer production. Many precursors are in huge scales available, like oleic acid ester (biodiesel), oleyl alcohol (tensides), oleyl amines (tensides, lubricants). We show several ways to produce and separate and purify C18-α,ω-bifunctional compounds, using Grubbs 2nd Generation catalysts, starting from technical grade educts.}, language = {en} } @article{GrosshauserPettrak2023, author = {Großhauser, Christian and Pettrak, J{\"u}rgen}, title = {Die Rolle des Wasserstoffs in der Abwasserbehandlung}, series = {Wasser und Abfall}, journal = {Wasser und Abfall}, number = {7/8}, publisher = {Springer Fachmedien}, address = {Wiesbaden}, issn = {1436-9095}, doi = {10.1007/s35152-023-1444-4}, year = {2023}, abstract = {Die Bereitstellung von nachhaltig erzeugtem Wasserstoff als Energietr{\"a}ger und Rohstoff ist eine wichtige Schl{\"u}sseltechnologie sowohl als Ersatz f{\"u}r fossile Energietr{\"a}ger, aber auch als Produkt im Zusammenhang mit Kreislaufprozessen. In der Abwasserbehandlung bestehen verschiedene M{\"o}glichkeiten Wasserstoff herzustellen. Mehrere Wege, m{\"o}gliche Synergien, aber auch deren Nachteile werden vorgestellt.}, language = {de} } @article{RakeEnningKurthetal.1994, author = {Rake, Heinrich and Enning, Manfred and Kurth, Johannes and Schr{\"o}der, Walter}, title = {Automatic uncoupler completes automation at the hump}, series = {RGI - Railway Gazette International}, volume = {150}, journal = {RGI - Railway Gazette International}, number = {6}, publisher = {Reed Business}, address = {Sutton}, issn = {0373-5346}, pages = {371 -- 374}, year = {1994}, language = {en} } @article{RakeSchwanhaeusserFrederichetal.1993, author = {Rake, Heinrich and Schwanh{\"a}ußer, Wulf and Frederich, Fritz and Enning, Manfred}, title = {Automatisierung von Ablaufanlagen mit dem Kupplungsroboter}, series = {ETR - Eisenbahntechnische Rundschau}, journal = {ETR - Eisenbahntechnische Rundschau}, number = {4}, publisher = {DVV Media Group}, address = {Hamburg}, issn = {0013-2845}, pages = {249 -- 254}, year = {1993}, language = {de} } @article{ManfredMaySutter2020, author = {Manfred, Enning and May, J{\"o}rg and Sutter, Stefan}, title = {Innovation am G{\"u}terwagen am Beispiel der Automatischen Bremsprobe}, series = {ETR - Eisenbahntechnische Rundschau}, journal = {ETR - Eisenbahntechnische Rundschau}, number = {12}, publisher = {DVV Media Group}, address = {Hamburg}, issn = {0013-2845}, pages = {14 -- 19}, year = {2020}, abstract = {Mit der Digitalen Automatischen Kupplung beginnt ein neues Kapitel des Schieneng{\"u}terverkehrs, in dem zusammengestellte Wagen sich automatisch in wenigen Minuten abfahrbereit machen, ohne dass der Mensch eingreifen muss. Eines des gr{\"o}ßten Hemmnisse der umweltfreundlichen Schiene wird dann entfallen. Notwendig ist jetzt eine Diskussion {\"u}ber den Umfang und die Systemgrenzen der Automatischen Bremsprobe.}, language = {de} } @article{EnningSchmidtWilbring2019, author = {Enning, Manfred and Schmidt, Bernd and Wilbring, Daniela}, title = {Auf dem Weg zur autonomen Anschlussbedienung}, series = {Privatbahn-Magazin}, journal = {Privatbahn-Magazin}, number = {3}, publisher = {Bahn Media}, address = {Suhlendorf}, issn = {1865-0163}, pages = {40 -- 43}, year = {2019}, language = {de} } @article{EnningPfaff2017, author = {Enning, Manfred and Pfaff, Raphael}, title = {G{\"u}terwagen 4.0 - Mehr als nur technischer Fortschritt}, series = {Privatbahn-Magazin}, journal = {Privatbahn-Magazin}, number = {2}, publisher = {Bahn Media}, address = {Suhlendorf}, issn = {1865-0163}, pages = {21 -- 25}, year = {2017}, abstract = {Lokomotiven sind dank modernster Konzepte der Antriebstechnik heute energiesparend und umweltfreundlich. Eine Ausr{\"u}stung mit Telematik und Assistenzfunktionen ist Standard. Auf der Strecke zeigt sich moderne Technik in Form elektronischer Stellwerke und Zugsicherungssysteme und in Rangier- und Abstellanlagen als EOW-Technik. Am G{\"u}terwagen hingegen ist der technische Fortschritt komplett vorbeigegangen. Auch beim modernsten Wagen (Abb. 1) ist die einzige „Automatik"-Funktion die zentral {\"u}ber die Hauptluftleitung (HL) versorgte und bet{\"a}tigte Luftbremse.}, language = {de} } @article{EnningPfaff2016, author = {Enning, Manfred and Pfaff, Raphael}, title = {Digitalisierung bringt mehr G{\"u}ter auf die Schiene}, series = {Sonderprojekte ATM/MTZ}, volume = {21}, journal = {Sonderprojekte ATM/MTZ}, number = {6 (suppl.)}, publisher = {Springer Fachmedien}, address = {Wiesbaden}, issn = {2509-4610}, doi = {10.1007/s41491-016-0570-7}, pages = {34 -- 37}, year = {2016}, language = {de} } @article{AsarStapenhorst2020, author = {Asar, Hande and Stapenhorst, Carolin}, title = {Zvi Hecker: Drawing on drawing}, series = {Archives of Design Research}, volume = {33}, journal = {Archives of Design Research}, number = {3}, publisher = {Korean Society of Design Science}, address = {Seongnam}, issn = {1226-8046}, doi = {10.15187/adr.2020.08.33.3.45}, pages = {45 -- 53}, year = {2020}, abstract = {Background: Architectural representation, nurtured by the interaction between design thinking and design action, is inherently multi-layered. However, the representation object cannot always reflect these layers. Therefore, it is claimed that these reflections and layerings can gain visibility through 'performativity in personal knowledge', which basically has a performative character. The specific layers of representation produced during the performativity in personal knowledge permit insights about the 'personal way of designing' [1]. Therefore, the question, 'how can these layered drawings be decomposed to understand the personal way of designing', can be defined as the beginning of the study. On the other hand, performativity in personal knowledge in architectural design is handled through the relationship between explicit and tacit knowledge and representational and non-representational theory. To discuss the practical dimension of these theoretical relations, Zvi Hecker's drawing of the Heinz-Galinski-School is examined as an example. The study aims to understand the relationships between the layers by decomposing a layered drawing analytically in order to exemplify personal ways of designing. Methods: The study is based on qualitative research methodologies. First, a model has been formed through theoretical readings to discuss the performativity in personal knowledge. This model is used to understand the layered representations and to research the personal way of designing. Thus, one drawing of Hecker's Heinz-Galinski-School project is chosen. Second, its layers are decomposed to detect and analyze diverse objects, which hint to different types of design tools and their application. Third, Zvi Hecker's statements of the design process are explained through the interview data [2] and other sources. The obtained data are compared with each other. Results: By decomposing the drawing, eleven layers are defined. These layers are used to understand the relation between the design idea and its representation. They can also be thought of as a reading system. In other words, a method to discuss Hecker's performativity in personal knowledge is developed. Furthermore, the layers and their interconnections are described in relation to Zvi Hecker's personal way of designing. Conclusions: It can be said that layered representations, which are associated with the multilayered structure of performativity in personal knowledge, form the personal way of designing.}, language = {en} } @article{StapenhorstZabekHildebrand2018, author = {Stapenhorst, Carolin and Zabek, Magdalena and Hildebrand, Linda}, title = {Communication process and information flow in the architectural planning context}, series = {Creativity game : theory and practice of spatial planning}, journal = {Creativity game : theory and practice of spatial planning}, number = {6}, publisher = {University of Ljubljana}, address = {Ljubljana}, doi = {10.15292/IU-CG.2018.06.066-073}, pages = {66 -- 73}, year = {2018}, abstract = {Against the background of growing data in everyday life, data processing tools become more powerful to deal with the increasing complexity in building design. The architectural planning process is offered a variety of new instruments to design, plan and communicate planning decisions. Ideally the access to information serves to secure and document the quality of the building and in the worst case, the increased data absorbs time by collection and processing without any benefit for the building and its user. Process models can illustrate the impact of information on the design- and planning process so that architect and planner can steer the process. This paper provides historic and contemporary models to visualize the architectural planning process and introduces means to describe today's situation consisting of stakeholders, events and instruments. It explains conceptions during Renaissance in contrast to models used in the second half of the 20th century. Contemporary models are discussed regarding their value against the background of increasing computation in the building process.}, language = {en} } @article{StapenhorstMotta2018, author = {Stapenhorst, Carolin and Motta, Luciano}, title = {Citt{\`a} Olivettiana in Ivrea, Italien}, series = {Bauwelt}, volume = {109}, journal = {Bauwelt}, number = {22}, publisher = {Bauverlag BV}, address = {G{\"u}tersloh}, issn = {0005-6855}, pages = {20 -- 31}, year = {2018}, language = {de} } @article{StapenhorstDutto2016, author = {Stapenhorst, Carolin and Dutto, Andrea Alberto}, title = {Notes on conceptual learning in architecture}, series = {Cartha - The Form of Form}, journal = {Cartha - The Form of Form}, address = {Basel}, year = {2016}, language = {en} } @article{KohlKraemerFohryetal.2024, author = {Kohl, Philipp and Kr{\"a}mer, Yoka and Fohry, Claudia and Kraft, Bodo}, title = {Scoping review of active learning strategies and their evaluation environments for entity recognition tasks}, series = {Deep learning theory and applications}, journal = {Deep learning theory and applications}, editor = {Fred, Ana and Hadjali, Allel and Gusikhin, Oleg and Sansone, Carlo}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-66694-0 (online ISBN)}, doi = {10.1007/978-3-031-66694-0_6}, pages = {84 -- 106}, year = {2024}, abstract = {We conducted a scoping review for active learning in the domain of natural language processing (NLP), which we summarize in accordance with the PRISMA-ScR guidelines as follows: Objective: Identify active learning strategies that were proposed for entity recognition and their evaluation environments (datasets, metrics, hardware, execution time). Design: We used Scopus and ACM as our search engines. We compared the results with two literature surveys to assess the search quality. We included peer-reviewed English publications introducing or comparing active learning strategies for entity recognition. Results: We analyzed 62 relevant papers and identified 106 active learning strategies. We grouped them into three categories: exploitation-based (60x), exploration-based (14x), and hybrid strategies (32x). We found that all studies used the F1-score as an evaluation metric. Information about hardware (6x) and execution time (13x) was only occasionally included. The 62 papers used 57 different datasets to evaluate their respective strategies. Most datasets contained newspaper articles or biomedical/medical data. Our analysis revealed that 26 out of 57 datasets are publicly accessible. Conclusion: Numerous active learning strategies have been identified, along with significant open questions that still need to be addressed. Researchers and practitioners face difficulties when making data-driven decisions about which active learning strategy to adopt. Conducting comprehensive empirical comparisons using the evaluation environment proposed in this study could help establish best practices in the domain.}, language = {en} } @article{StapenhorstDutto2020, author = {Stapenhorst, Carolin and Dutto, Andrea Alberto}, title = {Turin: Industriedenkmal wird Kulturzentrum wird Lazarett}, series = {Bauwelt}, volume = {111}, journal = {Bauwelt}, number = {13}, publisher = {Bauverlag BV}, address = {G{\"u}tersloh}, issn = {0005-6855}, pages = {56 -- 59}, year = {2020}, language = {de} } @article{MikuckiSchulerDigeletal.2023, author = {Mikucki, Jill Ann and Schuler, C. G. and Digel, Ilya and Kowalski, Julia and Tuttle, M. J. and Chua, Michelle and Davis, R. and Purcell, Alicia and Ghosh, D. and Francke, G. and Feldmann, Marco and Espe, C. and Heinen, Dirk and Dachwald, Bernd and Clemens, Joachim and Lyons, W. B. and Tulaczyk, S.}, title = {Field-Based planetary protection operations for melt probes: validation of clean access into the blood falls, antarctica, englacial ecosystem}, series = {Astrobiology}, volume = {23}, journal = {Astrobiology}, number = {11}, publisher = {Liebert}, address = {New York, NY}, issn = {1557-8070 (online)}, doi = {10.1089/ast.2021.0102}, pages = {1165 -- 1178}, year = {2023}, abstract = {Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063\% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.}, language = {en} } @article{AkimbekovDigelTastambeketal.2024, author = {Akimbekov, Nuraly S. and Digel, Ilya and Tastambek, Kuanysh T. and Kozhahmetova, Marzhan and Sherelkhan, Dinara K. and Tauanov, Zhandos}, title = {Hydrogenotrophic methanogenesis in coal-bearing environments: Methane production, carbon sequestration, and hydrogen availability}, series = {International Journal of Hydrogen Energy}, volume = {52}, journal = {International Journal of Hydrogen Energy}, number = {Part D}, publisher = {Elsevier}, address = {New York}, issn = {1879-3487 (online)}, doi = {10.1016/j.ijhydene.2023.09.223}, pages = {1264 -- 1277}, year = {2024}, abstract = {Methane is a valuable energy source helping to mitigate the growing energy demand worldwide. However, as a potent greenhouse gas, it has also gained additional attention due to its environmental impacts. The biological production of methane is performed primarily hydrogenotrophically from H2 and CO2 by methanogenic archaea. Hydrogenotrophic methanogenesis also represents a great interest with respect to carbon re-cycling and H2 storage. The most significant carbon source, extremely rich in complex organic matter for microbial degradation and biogenic methane production, is coal. Although interest in enhanced microbial coalbed methane production is continuously increasing globally, limited knowledge exists regarding the exact origins of the coalbed methane and the associated microbial communities, including hydrogenotrophic methanogens. Here, we give an overview of hydrogenotrophic methanogens in coal beds and related environments in terms of their energy production mechanisms, unique metabolic pathways, and associated ecological functions.}, language = {en} } @article{WindmuellerSchapsZantisetal.2024, author = {Windm{\"u}ller, Anna and Schaps, Kristian and Zantis, Frederik and Domgans, Anna and Taklu, Bereket Woldegbreal and Yang, Tingting and Tsai, Chih-Long and Schierholz, Roland and Yu, Shicheng and Kungl, Hans and Tempel, Hermann and Dunin-Borkowski, Rafal E. and H{\"u}ning, Felix and Hwang, Bing Joe and Eichel, R{\"u}diger-A.}, title = {Electrochemical activation of LiGaO2: implications for ga-doped garnet solid electrolytes in li-metal batteries}, series = {ACS Applied Materials \& Interfaces}, volume = {16}, journal = {ACS Applied Materials \& Interfaces}, number = {30}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {39181-3919}, doi = {10.1021/acsami.4c03729}, pages = {14 Seiten}, year = {2024}, abstract = {Ga-doped Li7La3Zr2O12 garnet solid electrolytes exhibit the highest Li-ion conductivities among the oxide-type garnet-structured solid electrolytes, but instabilities toward Li metal hamper their practical application. The instabilities have been assigned to direct chemical reactions between LiGaO2 coexisting phases and Li metal by several groups previously. Yet, the understanding of the role of LiGaO2 in the electrochemical cell and its electrochemical properties is still lacking. Here, we are investigating the electrochemical properties of LiGaO2 through electrochemical tests in galvanostatic cells versus Li metal and complementary ex situ studies via confocal Raman microscopy, quantitative phase analysis based on powder X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electron energy loss spectroscopy. The results demonstrate considerable and surprising electrochemical activity, with high reversibility. A three-stage reaction mechanism is derived, including reversible electrochemical reactions that lead to the formation of highly electronically conducting products. The results have considerable implications for the use of Ga-doped Li7La3Zr2O12 electrolytes in all-solid-state Li-metal battery applications and raise the need for advanced materials engineering to realize Ga-doped Li7La3Zr2O12for practical use.}, language = {en} } @article{EichlerBalcBremenetal.2024, author = {Eichler, Fabian and Balc, Nicolae and Bremen, Sebastian and Nink, Philipp}, title = {Investigation of laser powder bed fusion parameters with respect to their influence on the thermal conductivity of 316L samples}, series = {Journal of Manufacturing and Materials Processing}, volume = {8}, journal = {Journal of Manufacturing and Materials Processing}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2504-4494}, doi = {10.3390/jmmp8040166}, pages = {12 Seiten}, year = {2024}, abstract = {The thermal conductivity of components manufactured using Laser Powder Bed Fusion (LPBF), also called Selective Laser Melting (SLM), plays an important role in their processing. Not only does a reduced thermal conductivity cause residual stresses during the process, but it also makes subsequent processes such as the welding of LPBF components more difficult. This article uses 316L stainless steel samples to investigate whether and to what extent the thermal conductivity of specimens can be influenced by different LPBF parameters. To this end, samples are set up using different parameters, orientations, and powder conditions and measured by a heat flow meter using stationary analysis. The heat flow meter set-up used in this study achieves good reproducibility and high measurement accuracy, so that comparative measurements between the various LPBF influencing factors to be tested are possible. In summary, the series of measurements show that the residual porosity of the components has the greatest influence on conductivity. The degradation of the powder due to increased recycling also appears to be detectable. The build-up direction shows no detectable effect in the measurement series.}, language = {en} } @article{ZhantlessovaSavitskayaKistaubayevaetal.2024, author = {Zhantlessova, Sirina and Savitskaya, Irina and Kistaubayeva, Aida and Ignatova, Ludmila and Talipova, Aizhan and Pogrebnjak, Alexander and Digel, Ilya}, title = {Correction: Zhantlessova et al. advanced "Green" prebiotic composite of bacterial cellulose/pullulan based on synthetic biology-powered microbial coculture strategy. Polymers 2022, 14, 3224}, series = {Polymers}, volume = {16}, journal = {Polymers}, number = {13}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {10.3390/polym16131802}, pages = {2 Seiten}, year = {2024}, language = {en} } @article{SchopenNarayanBeckmannetal.2024, author = {Schopen, Oliver and Narayan, Sriram and Beckmann, Marvin and Najmi, Aezid-Ul-Hassan and Esch, Thomas and Shabani, Bahman}, title = {An EIS approach to quantify the effects of inlet air relative humidity on the performance of proton exchange membrane fuel cells: a pathway to developing a novel fault diagnostic method}, series = {International Journal of Hydrogen Energy}, volume = {58}, journal = {International Journal of Hydrogen Energy}, number = {8}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0360-3199 (print)}, issn = {1879-3487 (online)}, doi = {10.1016/j.ijhydene.2024.01.218}, pages = {1302 -- 1315}, year = {2024}, abstract = {In this work, the effect of low air relative humidity on the operation of a polymer electrolyte membrane fuel cell is investigated. An innovative method through performing in situ electrochemical impedance spectroscopy is utilised to quantify the effect of inlet air relative humidity at the cathode side on internal ionic resistances and output voltage of the fuel cell. In addition, algorithms are developed to analyse the electrochemical characteristics of the fuel cell. For the specific fuel cell stack used in this study, the membrane resistance drops by over 39 \% and the cathode side charge transfer resistance decreases by 23 \% after increasing the humidity from 30 \% to 85 \%, while the results of static operation also show an increase of ∼2.2 \% in the voltage output after increasing the relative humidity from 30 \% to 85 \%. In dynamic operation, visible drying effects occur at < 50 \% relative humidity, whereby the increase of the air side stoichiometry increases the drying effects. Furthermore, other parameters, such as hydrogen humidification, internal stack structure, and operating parameters like stoichiometry, pressure, and temperature affect the overall water balance. Therefore, the optimal humidification range must be determined by considering all these parameters to maximise the fuel cell performance and durability. The results of this study are used to develop a health management system to ensure sufficient humidification by continuously monitoring the fuel cell polarisation data and electrochemical impedance spectroscopy indicators.}, language = {en} } @article{SchopenShahEschetal.2024, author = {Schopen, Oliver and Shah, Neel and Esch, Thomas and Shabani, Bahman}, title = {Critical quantitative evaluation of integrated health management methods for fuel cell applications}, series = {International Journal of Hydrogen Energy}, volume = {70}, journal = {International Journal of Hydrogen Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2024.05.156}, pages = {370 -- 388}, year = {2024}, abstract = {Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system.}, language = {en} } @article{DroopChenRadfordetal.2023, author = {Droop, Philipp and Chen, Shaohuang and Radford, Melissa J. and Paulßen, Elisabeth and Gates, Byron D. and Reilly, Raymond M. and Radchenko, Valery and Hoehr, Cornelia}, title = {Synthesis of 197m/gHg labelled gold nanoparticles for targeted radionuclide therapy}, series = {Radiochimica Acta}, volume = {111}, journal = {Radiochimica Acta}, number = {10}, publisher = {De Gruyter}, address = {Berlin [u.a.]}, issn = {2193-3405}, doi = {10.1515/ract-2023-0144}, pages = {773 -- 779}, year = {2023}, abstract = {Meitner-Auger-electron emitters have a promising potential for targeted radionuclide therapy of cancer because of their short range and the high linear energy transfer of Meitner-Auger-electrons (MAE). One promising MAE candidate is 197m/gHg with its half-life of 23.8 h and 64.1 h, respectively, and high MAE yield. Gold nanoparticles (AuNPs) that are labelled with 197m/gHg could be a helpful tool for radiation treatment of glioblastoma multiforme when infused into the surgical cavity after resection to prevent recurrence. To produce such AuNPs, 197m/gHg was embedded into pristine AuNPs. Two different syntheses were tested starting from irradiated gold containing trace amounts of 197m/gHg. When sodium citrate was used as reducing agent, no 197m/gHg labelled AuNPs were formed, but with tannic acid, 197m/gHg labeled AuNPs were produced. The method was optimized by neutralizing the pH (pH = 7) of the Au/197m/gHg solution, which led to labelled AuNPs with a size of 12.3 ± 2.0 nm as measured by transmission electron microscopy. The labelled AuNPs had a concentration of 50 μg (gold)/mL with an activity of 151 ± 93 kBq/mL (197gHg, time corrected to the end of bombardment).}, language = {en} } @article{MuesgenanntKoersMcNeilRadchenkoetal.2023, author = {Mues genannt Koers, Lucas and McNeil, S. W. and Radchenko, V. and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Production of Co-58m in a siphon-style liquid target on a medical cyclotron}, volume = {195}, number = {Art. 110734}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0969-8043}, doi = {10.1016/j.apradiso.2023.110734}, year = {2023}, abstract = {We present the production of 58mCo on a small, 13 MeV medical cyclotron utilizing a siphon style liquid target system. Different concentrated iron(III)-nitrate solutions of natural isotopic distribution were irradiated at varying initial pressures and subsequently separated by solid phase extraction chromatography. The radio cobalt (58m/gCo and 56Co) was successfully produced with saturation activities of (0.35 ± 0.03) MBq μA-1 for 58mCo with a separation recovery of (75 ± 2) \% of cobalt after one separation step utilizing LN-resin.}, language = {en} } @article{MuesgenanntKoersPrevostPaulssenetal.2023, author = {Mues genannt Koers, Lucas and Prevost, David and Paulßen, Elisabeth and Hoehr, Cornelia}, title = {Density reduction effects on the production of [11C]CO2 in Nb-body targets on a medical cyclotron}, volume = {199}, number = {Art. 110911}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.apradiso.2023.110911}, year = {2023}, abstract = {Medical isotope production of 11C is commonly performed in gaseous targets. The power deposition of the proton beam during the irradiation decreases the target density due to thermodynamic mixing and can cause an increase of penetration depth and divergence of the proton beam. In order to investigate the difference how the target-body length influences the operation conditions and the production yield, a 12 cm and a 22 cm Nb-target body containing N2/O2 gas were irradiated using a 13 MeV proton cyclotron. It was found that the density reduction has a large influence on the pressure rise during irradiation and the achievable radioactive yield. The saturation activity of [11C]CO2 for the long target (0.083 Ci/μA) is about 10\% higher than in the short target geometry (0.075 Ci/μA).}, language = {en} } @article{KleefeldPieronek2020, author = {Kleefeld, Andreas and Pieronek, J.}, title = {Elastic transmission eigenvalues and their computation via the method of fundamental solutions}, series = {Applicable Analysis}, volume = {100}, journal = {Applicable Analysis}, number = {16}, publisher = {Taylore \& Francis}, address = {London}, issn = {1563-504X}, doi = {10.1080/00036811.2020.1721473}, pages = {3445 -- 3462}, year = {2020}, abstract = {A stabilized version of the fundamental solution method to catch ill-conditioning effects is investigated with focus on the computation of complex-valued elastic interior transmission eigenvalues in two dimensions for homogeneous and isotropic media. Its algorithm can be implemented very shortly and adopts to many similar partial differential equation-based eigenproblems as long as the underlying fundamental solution function can be easily generated. We develop a corroborative approximation analysis which also implicates new basic results for transmission eigenfunctions and present some numerical examples which together prove successful feasibility of our eigenvalue recovery approach.}, language = {en} } @article{SaretzkiBergmannDahmannetal.2021, author = {Saretzki, Charlotte and Bergmann, Ole and Dahmann, Peter and Janser, Frank and Keimer, Jona and Machado, Patricia and Morrison, Audry and Page, Henry and Pluta, Emil and St{\"u}bing, Felix and K{\"u}pper, Thomas}, title = {Are small airplanes safe with regards to COVID-19 transmission?}, series = {Journal of Travel Medicine}, volume = {28}, journal = {Journal of Travel Medicine}, number = {7}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1708-8305}, doi = {10.1093/jtm/taab105}, year = {2021}, language = {en} } @article{Bung2024, author = {Bung, Daniel Bernhard}, title = {Kamerabasierte Fließtiefen- und Geschwindigkeitsmessungen}, series = {Wasserwirtschaft}, volume = {114}, journal = {Wasserwirtschaft}, number = {4}, publisher = {Springer Vieweg}, address = {Wiesbaden}, issn = {0043-0978}, pages = {47 -- 53}, year = {2024}, abstract = {In der wasserbaulichen Forschung werden neben klassischen Messinstrumenten zunehmend kamerabasierte Verfahren genutzt. Diese erlauben neben der Bestimmung von Fließgeschwindigkeiten auch die Detektion der freien Wasseroberfl{\"a}che oder zeitliche Vermessung von Kolken. Durch die hohen r{\"a}umlichen und zeitlichen Aufl{\"o}sungen, welche neueste Kamerasensoren liefern, k{\"o}nnen neue Erkenntnisse in turbulenten, komplexen Str{\"o}mungen gewonnen werden. Auch in der Praxis k{\"o}nnen diese Verfahren mit geringem Aufwand wichtige Daten liefern.}, language = {de} } @article{OertelBung2021, author = {Oertel, Mario and Bung, Daniel Bernhard}, title = {Hochwasserschutz - eine Aufgabe f{\"u}r eine nachhaltige Wasserwirtschaft}, series = {Wasserwirtschaft}, volume = {111}, journal = {Wasserwirtschaft}, number = {9-10}, publisher = {Springer Vieweg}, address = {Wiesbaden}, issn = {0043-0978}, pages = {3 -- 19}, year = {2021}, language = {de} } @article{Bung2021, author = {Bung, Daniel Bernhard}, title = {Extreme flooding in Western Germany: some thoughts on hazards, return periods and risk}, series = {Hydrolink}, journal = {Hydrolink}, number = {4}, publisher = {International Association for Hydro-Environment Engineering and Research (IAHR)}, address = {Madrid}, pages = {108 -- 113}, year = {2021}, abstract = {The low-pressure system Bernd involved extreme rainfalls in the Western part of Germany in July 2021, resulting in major floods, severe damages and a tremendous number of casualties. Such extreme events are rare and full flood protection can never be ensured with reasonable financial means. But still, this event must be starting point to reconsider current design concepts. This article aims at sharing some thoughts on potential hazards, the selection of return periods and remaining risk with the focus on Germany.}, language = {en} } @article{AyalaHarrisKleefeld2024, author = {Ayala, Rafael Ceja and Harris, Isaac and Kleefeld, Andreas}, title = {Direct sampling method via Landweber iteration for an absorbing scatterer with a conductive boundary}, series = {Inverse Problems and Imaging}, volume = {18}, journal = {Inverse Problems and Imaging}, number = {3}, publisher = {AIMS}, address = {Springfield}, issn = {1930-8337}, doi = {10.3934/ipi.2023051}, pages = {708 -- 729}, year = {2024}, abstract = {In this paper, we consider the inverse shape problem of recovering isotropic scatterers with a conductive boundary condition. Here, we assume that the measured far-field data is known at a fixed wave number. Motivated by recent work, we study a new direct sampling indicator based on the Landweber iteration and the factorization method. Therefore, we prove the connection between these reconstruction methods. The method studied here falls under the category of qualitative reconstruction methods where an imaging function is used to recover the absorbing scatterer. We prove stability of our new imaging function as well as derive a discrepancy principle for recovering the regularization parameter. The theoretical results are verified with numerical examples to show how the reconstruction performs by the new Landweber direct sampling method.}, language = {en} } @article{ClausnitzerKleefeld2024, author = {Clausnitzer, Julian and Kleefeld, Andreas}, title = {A spectral Galerkin exponential Euler time-stepping scheme for parabolic SPDEs on two-dimensional domains with a C² boundary}, series = {Discrete and Continuous Dynamical Systems - Series B}, volume = {29}, journal = {Discrete and Continuous Dynamical Systems - Series B}, number = {4}, publisher = {AIMS}, address = {Springfield}, issn = {1531-3492}, doi = {10.3934/dcdsb.2023148}, pages = {1624 -- 1651}, year = {2024}, abstract = {We consider the numerical approximation of second-order semi-linear parabolic stochastic partial differential equations interpreted in the mild sense which we solve on general two-dimensional domains with a C² boundary with homogeneous Dirichlet boundary conditions. The equations are driven by Gaussian additive noise, and several Lipschitz-like conditions are imposed on the nonlinear function. We discretize in space with a spectral Galerkin method and in time using an explicit Euler-like scheme. For irregular shapes, the necessary Dirichlet eigenvalues and eigenfunctions are obtained from a boundary integral equation method. This yields a nonlinear eigenvalue problem, which is discretized using a boundary element collocation method and is solved with the Beyn contour integral algorithm. We present an error analysis as well as numerical results on an exemplary asymmetric shape, and point out limitations of the approach.}, language = {en} } @article{HarrisKleefeld2022, author = {Harris, Isaac and Kleefeld, Andreas}, title = {Analysis and computation of the transmission eigenvalues with a conductive boundary condition}, series = {Applicable Analysis}, volume = {101}, journal = {Applicable Analysis}, number = {6}, publisher = {Taylor \& Francis}, address = {London}, issn = {1563-504X}, doi = {10.1080/00036811.2020.1789598}, pages = {1880 -- 1895}, year = {2022}, abstract = {We provide a new analytical and computational study of the transmission eigenvalues with a conductive boundary condition. These eigenvalues are derived from the scalar inverse scattering problem for an inhomogeneous material with a conductive boundary condition. The goal is to study how these eigenvalues depend on the material parameters in order to estimate the refractive index. The analytical questions we study are: deriving Faber-Krahn type lower bounds, the discreteness and limiting behavior of the transmission eigenvalues as the conductivity tends to infinity for a sign changing contrast. We also provide a numerical study of a new boundary integral equation for computing the eigenvalues. Lastly, using the limiting behavior we will numerically estimate the refractive index from the eigenvalues provided the conductivity is sufficiently large but unknown.}, language = {en} } @article{ChwallekNawrathKrastinaetal.2024, author = {Chwallek, Constanze and Nawrath, Lara and Krastina, Anzelika and Bruksle, Ieva}, title = {Supportive research on sustainable entrepreneurship and business practices}, series = {SECA Sustainable Entrepreneurship for Climate Action}, journal = {SECA Sustainable Entrepreneurship for Climate Action}, number = {3}, publisher = {Lapland University of Applied Sciences Ltd}, address = {Rovaniemi}, isbn = {978-952-316-514-4 (pdf)}, issn = {2954-1654 (on-line publication)}, pages = {67 Seiten}, year = {2024}, language = {en} } @article{KleefeldZimmermann2022, author = {Kleefeld, Andreas and Zimmermann, M.}, title = {Computing Elastic Interior Transmission Eigenvalues}, series = {Integral Methods in Science and Engineering}, journal = {Integral Methods in Science and Engineering}, editor = {Constanda, Christian and Bodmann, Bardo E.J. and Harris, Paul J.}, publisher = {Birkh{\"a}user}, address = {Cham}, isbn = {978-3-031-07171-3}, doi = {10.1007/978-3-031-07171-3_10}, pages = {139 -- 155}, year = {2022}, abstract = {An alternative method is presented to numerically compute interior elastic transmission eigenvalues for various domains in two dimensions. This is achieved by discretizing the resulting system of boundary integral equations in combination with a nonlinear eigenvalue solver. Numerical results are given to show that this new approach can provide better results than the finite element method when dealing with general domains.}, language = {en} }