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Carbon nanofiber nonwovens represent a powerful class of materials with prospective application in filtration technology or as electrodes with high surface area in batteries, fuel cells, and supercapacitors. While new precursor-to-carbon conversion processes have been explored to overcome productivity restrictions for carbon fiber tows, alternatives for the two-step thermal conversion of polyacrylonitrile precursors into carbon fiber nonwovens are absent. In this work, we develop a continuous roll-to-roll stabilization process using an atmospheric pressure microwave plasma jet. We explore the influence of various plasma-jet parameters on the morphology of the nonwoven and compare the stabilized nonwoven to thermally stabilized samples using scanning electron microscopy, differential scanning calorimetry, and infrared spectroscopy. We show that stabilization with a non-equilibrium plasma-jet can be twice as productive as the conventional thermal stabilization in a convection furnace, while producing electrodes of comparable electrochemical performance.
Atmospheric pressure plasma-jet treatment of PAN-nonwovens—carbonization of nanofiber electrodes
(2022)
Carbon nanofibers are produced from dielectric polymer precursors such as polyacrylonitrile (PAN). Carbonized nanofiber nonwovens show high surface area and good electrical conductivity, rendering these fiber materials interesting for application as electrodes in batteries, fuel cells, and supercapacitors. However, thermal processing is slow and costly, which is why new processing techniques have been explored for carbon fiber tows. Alternatives for the conversion of PAN-precursors into carbon fiber nonwovens are scarce. Here, we utilize an atmospheric pressure plasma jet to conduct carbonization of stabilized PAN nanofiber nonwovens. We explore the influence of various processing parameters on the conductivity and degree of carbonization of the converted nanofiber material. The precursor fibers are converted by plasma-jet treatment to carbon fiber nonwovens within seconds, by which they develop a rough surface making subsequent surface activation processes obsolete. The resulting carbon nanofiber nonwovens are applied as supercapacitor electrodes and examined by cyclic voltammetry and impedance spectroscopy. Nonwovens that are carbonized within 60 s show capacitances of up to 5 F g⁻¹.
In this study, an online multi-sensing platform was engineered to simultaneously evaluate various process parameters of food package sterilization using gaseous hydrogen peroxide (H₂O₂). The platform enabled the validation of critical aseptic parameters. In parallel, one series of microbiological count reduction tests was performed using highly resistant spores of B. atrophaeus DSM 675 to act as the reference method for sterility validation. By means of the multi-sensing platform together with microbiological tests, we examined sterilization process parameters to define the most effective conditions with regards to the highest spore kill rate necessary for aseptic packaging. As these parameters are mutually associated, a correlation between different factors was elaborated. The resulting correlation indicated the need for specific conditions regarding the applied H₂O₂ gas temperature, the gas flow and concentration, the relative humidity and the exposure time. Finally, the novel multi-sensing platform together with the mobile electronic readout setup allowed for the online and on-site monitoring of the sterilization process, selecting the best conditions for sterility and, at the same time, reducing the use of the time-consuming and costly microbiological tests that are currently used in the food package industry.
Alte, geschichtsrelevante und thematisch angeordnete Objekte, welche man in den Vitrinen der Museen betrachten kann, das kennt sicher jeder. Doch wie kommen diese Artefakte eigentlich in die Vitrinen? Welche Menschen sind dafür verantwortlich, dass wir diese Kulturgüter bestaunen können? In diesem temporären Ausstellungskonzept für das Römisch-Germanische Museum Köln geht es darum, die sonst verborgene Arbeit der Restauratoren des Museums für die Besucher:innen sichtbar zu machen, ihnen genauere Einblicke in die Arbeit mit ihren Anforderungen zu geben und Restaurierungsprozesse auf zu zeigen. Diese Arbeit demonstriert, wie es abseits der Öffentlichkeit aussieht und wer dafür verantwortlich ist, dass wir einen Einblick in die vergangenen Zeit erhalten können. Das Projekt zeigt eine mögliche Bespielung des Museums, wie das Berufsbild der Restauratoren in die Dauerausstellung integriert werden könnte.
We present a concise mini overview on the approaches to the disposal of nuclear waste currently used or deployed. The disposal of nuclear waste is the end point of nuclear waste management (NWM) activities and is the emplacement of waste in an appropriate facility without the intention to retrieve it. The IAEA has developed an internationally accepted classification scheme based on the end points of NWM, which is used as guidance. Retention times needed for safe isolation of waste radionuclides are estimated based on the radiotoxicity of nuclear waste. Disposal facilities usually rely on a multi-barrier defence system to isolate the waste from the biosphere, which comprises the natural geological barrier and the engineered barrier system. Disposal facilities could be of a trench type, vaults, tunnels, shafts, boreholes, or mined repositories. A graded approach relates the depth of the disposal facilities’ location with the level of hazard. Disposal practices demonstrate the reliability of nuclear waste disposal with minimal expected impacts on the environment and humans.
Process mining gets more and more attention even outside large enterprises and can be a major benefit for small and medium sized enterprises (SMEs) to gain competitive advantages. Applying process mining is challenging, particularly for SMEs because they have less resources and process maturity. So far, IS researchers analyzed process mining challenges with a focus on larger companies. This paper investigates the application of process mining by means of a case study and sheds light into the particular challenges of an IT SME. The results reveal 13 SME process mining challenges and seven guidelines to address them. In this way, the paper contributes to the understanding of process mining application in SME and shows similarities and differences to larger companies.
Non-intrusive measuring techniques have attained a lot of interest in relation to both hydraulic modeling and prototype applications. Complimenting acoustic techniques, significant progress has been made for the development of new optical methods. Computer vision techniques can help to extract new information, e. g. high-resolution velocity and depth data, from videos captured with relatively inexpensive, consumer-grade cameras. Depth cameras are sensors providing information on the distance between the camera and observed features. Currently, sensors with different working principles are available. Stereoscopic systems reference physical image features (passive system) from two perspectives; in order to enhance the number of features and improve the results, a sensor may also estimate the disparity from a detected light to its original projection (active stereo system). In the current study, the RGB-D camera Intel RealSense D435, working on such stereo vision principle, is used in different, typical hydraulic modeling applications. All tests have been conducted at the Utah Water Research Laboratory. This paper will demonstrate the performance and limitations of the RGB-D sensor, installed as a single camera and as camera arrays, applied to 1) detect the free surface for highly turbulent, aerated hydraulic jumps, for free-falling jets and for an energy dissipation basin downstream of a labyrinth weir and 2) to monitor local scours upstream and downstream of a Piano Key Weir. It is intended to share the authors’ experiences with respect to camera settings, calibration, lightning conditions and other requirements in order to promote this useful, easily accessible device. Results will be compared to data from classical instrumentation and the literature. It will be shown that even in difficult application, e. g. the detection of a highly turbulent, fluctuating free-surface, the RGB-D sensor may yield similar accuracy as classical, intrusive probes.
Der Personalmangel in der Pflege ist vor allem durch die Pandemie in den Fokus der Öffentlichkeit gerückt. Diese Situation wird sich in den nächsten Jahren aufgrund der steigenden Pflegequote in Folge des demografischen Wandels weiter zuspitzen. Das Dokumentieren der durchgeführten Tätigkeiten nimmt dabei viel Zeit in Anspruch, die nicht den Bewohner:innen zugutekommt. Das Dokumentationssystem „Applause“ soll Pflege- und Betreuungskräfte in ihrer Arbeit unterstützen und durch die einfache Nutzerführung den Schulungsaufwand reduzieren. Durch die Integration von modernen medizinischen Sensoren kann innerhalb des Systems der aktuelle Gesundheitsstatus der Bewohner:innen eingesehen werden. Zusätzlich wird die interne sowie externe Kommunikation innerhalb des Dokumentationssystems abgebildet. Bei Letzterer wird mittels einer datenschutzkonformen Software die auf Fax basierende Kommunikation abgelöst.
Auch in der allgemeinen Luftfahrt wäre es wünschenswert, die bereits vorhandenen Verbrennungsmotoren mit weniger CO₂-trächtigen Kraftstoffen als dem heute weit verbreiteten Avgas 100LL betreiben zu können. Es ist anzunehmen, dass im Vergleich die unter Normalbedingungen gasförmigen Kraftstoffe CNG, LPG oder LNG deutlich weniger Emissionen produzieren. Erforderliche Antriebssystemanpassungen wurden im Rahmen eines Forschungsprojekts an der FH Aachen untersucht.
In the past, CSP and PV have been seen as competing technologies. Despite massive reductions in the electricity generation costs of CSP plants, PV power generation is - at least during sunshine hours - significantly cheaper. If electricity is required not only during the daytime, but around the clock, CSP with its inherent thermal energy storage gets an advantage in terms of LEC. There are a few examples of projects in which CSP plants and PV plants have been co-located, meaning that they feed into the same grid connection point and ideally optimize their operation strategy to yield an overall benefit. In the past eight years, TSK Flagsol has developed a plant concept, which merges both solar technologies into one highly Integrated CSP-PV-Hybrid (ICPH) power plant. Here, unlike in simply co-located concepts, as analyzed e.g. in [1] – [4], excess PV power that would have to be dumped is used in electric molten salt heaters to increase the storage temperature, improving storage and conversion efficiency. The authors demonstrate the electricity cost sensitivity to subsystem sizing for various market scenarios, and compare the resulting optimized ICPH plants with co-located hybrid plants. Independent of the three feed-in tariffs that have been assumed, the ICPH plant shows an electricity cost advantage of almost 20% while maintaining a high degree of flexibility in power dispatch as it is characteristic for CSP power plants. As all components of such an innovative concept are well proven, the system is ready for commercial market implementation. A first project is already contracted and in early engineering execution.
Analysis and computation of the transmission eigenvalues with a conductive boundary condition
(2022)
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.
This study investigated the anaerobic digestion of an algal–bacterial biofilm grown in artificial wastewater in an Algal Turf Scrubber (ATS). The ATS system was located in a greenhouse (50°54′19ʺN, 6°24′55ʺE, Germany) and was exposed to seasonal conditions during the experiment period. The methane (CH4) potential of untreated algal–bacterial biofilm (UAB) and thermally pretreated biofilm (PAB) using different microbial inocula was determined by anaerobic batch fermentation. Methane productivity of UAB differed significantly between microbial inocula of digested wastepaper, a mixture of manure and maize silage, anaerobic sewage sludge, and percolated green waste. UAB using sewage sludge as inoculum showed the highest methane productivity. The share of methane in biogas was dependent on inoculum. Using PAB, a strong positive impact on methane productivity was identified for the digested wastepaper (116.4%) and a mixture of manure and maize silage (107.4%) inocula. By contrast, the methane yield was significantly reduced for the digested anaerobic sewage sludge (50.6%) and percolated green waste (43.5%) inocula. To further evaluate the potential of algal–bacterial biofilm for biogas production in wastewater treatment and biogas plants in a circular bioeconomy, scale-up calculations were conducted. It was found that a 0.116 km2 ATS would be required in an average municipal wastewater treatment plant which can be viewed as problematic in terms of space consumption. However, a substantial amount of energy surplus (4.7–12.5 MWh a−1) can be gained through the addition of algal–bacterial biomass to the anaerobic digester of a municipal wastewater treatment plant. Wastewater treatment and subsequent energy production through algae show dominancy over conventional technologies.
An interdisciplinary view on humane interfaces for digital shadows in the internet of production
(2022)
Digital shadows play a central role for the next generation industrial internet, also known as Internet of Production (IoP). However, prior research has not considered systematically how human actors interact with digital shadows, shaping their potential for success. To address this research gap, we assembled an interdisciplinary team of authors from diverse areas of human-centered research to propose and discuss design and research recommendations for the implementation of industrial user interfaces for digital shadows, as they are currently conceptualized for the IoP. Based on the four use cases of decision support systems, knowledge sharing in global production networks, human-robot collaboration, and monitoring employee workload, we derive recommendations for interface design and enhancing workers’ capabilities. This analysis is extended by introducing requirements from the higher-level perspectives of governance and organization.
Cybersecurity of Industrial Control Systems (ICS) is an important issue, as ICS incidents may have a direct impact on safety of people or the environment. At the same time the awareness and knowledge about cybersecurity, particularly in the context of ICS, is alarmingly low. Industrial honeypots offer a cheap and easy to implement way to raise cybersecurity awareness and to educate ICS staff about typical attack patterns. When integrated in a productive network, industrial honeypots may not only reveal attackers early but may also distract them from the actual important systems of the network. Implementing multiple honeypots as a honeynet, the systems can be used to emulate or simulate a whole Industrial Control System. This paper describes a network of honeypots emulating HTTP, SNMP, S7communication and the Modbus protocol using Conpot, IMUNES and SNAP7. The nodes mimic SIMATIC S7 programmable logic controllers (PLCs) which are widely used across the globe. The deployed honeypots' features will be compared with the features of real SIMATIC S7 PLCs. Furthermore, the honeynet has been made publicly available for ten days and occurring cyberattacks have been analyzed
This work introduces a novel method for the detection of H₂O₂ vapor/aerosol of low concentrations, which is mainly applied in the sterilization of equipment in medical industry. Interdigitated electrode (IDE) structures have been fabricated by means of microfabrication techniques. A differential setup of IDEs was prepared, containing an active sensor element (active IDE) and a passive sensor element (passive IDE), where the former was immobilized with an enzymatic membrane of horseradish peroxidase that is selective towards H₂O₂. Changes in the IDEs’ capacitance values (active sensor element versus passive sensor element) under H₂O₂ vapor/aerosol atmosphere proved the detection in the concentration range up to 630 ppm with a fast response time (<60 s). The influence of relative humidity was also tested with regard to the sensor signal, showing no cross-sensitivity. The repeatability assessment of the IDE biosensors confirmed their stable capacitive signal in eight subsequent cycles of exposure to H₂O₂ vapor/aerosol. Room-temperature detection of H₂O₂ vapor/aerosol with such miniaturized biosensors will allow a future three-dimensional, flexible mapping of aseptic chambers and help to evaluate sterilization assurance in medical industry.
Edge-based and face-based smoothed finite element methods (ES-FEM and FS-FEM, respectively) are modified versions of the finite element method allowing to achieve more accurate results and to reduce sensitivity to mesh distortion, at least for linear elements. These properties make the two methods very attractive. However, their implementation in a standard finite element code is nontrivial because it requires heavy and extensive modifications to the code architecture. In this article, we present an element-based formulation of ES-FEM and FS-FEM methods allowing to implement the two methods in a standard finite element code with no modifications to its architecture. Moreover, the element-based formulation permits to easily manage any type of element, especially in 3D models where, to the best of the authors' knowledge, only tetrahedral elements are used in FS-FEM applications found in the literature. Shape functions for non-simplex 3D elements are proposed in order to apply FS-FEM to any standard finite element.
In der Arbeit »An den Rand gedrängt–Die Marginalisierung unserer Städte« wird anhand des Flächenverbrauchs des ruhenden Verkehrs erörtert, inwieweit der private Pkw die Entwicklung unserer Städte bestimmt. Die Zusammenstellung verschiedener Texte, Raumbeobachtungen und fotografischer Zeitdokumente soll die Problematik und Aktualität des Themas verstärken. Schritt für Schritt sollen die Leser:innen einen neuen Blick auf die eigene Stadt gewinnen und für das Problem der akuten Flächenknappheit sensibilisiert werden. Das Werk versteht sich als Aufruf, unseren Straßenraum zu entkarbonisieren, ihn neu zu entdecken und die möglichen Chancen im Wandel zu erkennen. Dabei geht es zunächst nicht um die Aufzählung von Klimaschäden, die Abschaffung von Parkplätzen oder gar des Autos, sondern um die Auswirkungen, die Parkplätze auf unser Leben haben und vor allem um ihr Potenzial für die Zukunft.
Retinal vessels are similar to cerebral vessels in their structure and function. Moderately low oscillation frequencies of around 0.1 Hz have been reported as the driving force for paravascular drainage in gray matter in mice and are known as the frequencies of lymphatic vessels in humans. We aimed to elucidate whether retinal vessel oscillations are altered in Alzheimer's disease (AD) at the stage of dementia or mild cognitive impairment (MCI). Seventeen patients with mild-to-moderate dementia due to AD (ADD); 23 patients with MCI due to AD, and 18 cognitively healthy controls (HC) were examined using Dynamic Retinal Vessel Analyzer. Oscillatory temporal changes of retinal vessel diameters were evaluated using mathematical signal analysis. Especially at moderately low frequencies around 0.1 Hz, arterial oscillations in ADD and MCI significantly prevailed over HC oscillations and correlated with disease severity. The pronounced retinal arterial vasomotion at moderately low frequencies in the ADD and MCI groups would be compatible with the view of a compensatory upregulation of paravascular drainage in AD and strengthen the amyloid clearance hypothesis.
Altered gastrocnemius contractile behavior in former achilles tendon rupture patients during walking
(2022)
Achilles tendon rupture (ATR) remains associated with functional limitations years after injury. Architectural remodeling of the gastrocnemius medialis (GM) muscle is typically observed in the affected leg and may compensate force deficits caused by a longer tendon. Yet patients seem to retain functional limitations during—low-force—walking gait. To explore the potential limits imposed by the remodeled GM muscle-tendon unit (MTU) on walking gait, we examined the contractile behavior of muscle fascicles during the stance phase. In a cross-sectional design, we studied nine former patients (males; age: 45 ± 9 years; height: 180 ± 7 cm; weight: 83 ± 6 kg) with a history of complete unilateral ATR, approximately 4 years post-surgery. Using ultrasonography, GM tendon morphology, muscle architecture at rest, and fascicular behavior were assessed during walking at 1.5 m⋅s–1 on a treadmill. Walking patterns were recorded with a motion capture system. The unaffected leg served as control. Lower limbs kinematics were largely similar between legs during walking. Typical features of ATR-related MTU remodeling were observed during the stance sub-phases corresponding to series elastic element (SEE) lengthening (energy storage) and SEE shortening (energy release), with shorter GM fascicles (36 and 36%, respectively) and greater pennation angles (8° and 12°, respectively). However, relative to the optimal fascicle length for force production, fascicles operated at comparable length in both legs. Similarly, when expressed relative to optimal fascicle length, fascicle contraction velocity was not different between sides, except at the time-point of peak series elastic element (SEE) length, where it was 39 ± 49% lower in the affected leg. Concomitantly, fascicles rotation during contraction was greater in the affected leg during the whole stance-phase, and architectural gear ratios (AGR) was larger during SEE lengthening. Under the present testing conditions, former ATR patients had recovered a relatively symmetrical walking gait pattern. Differences in seen AGR seem to accommodate the profound changes in MTU architecture, limiting the required fascicle shortening velocity. Overall, the contractile behavior of the GM fascicles does not restrict length- or velocity-dependent force potentials during this locomotor task.
Aeroux
(2022)
Aeroux ist eine Formstudie über die Gestalt einer Luftschiffgondel. Luftschiffe bzw. Zeppeline werden oft mit dem Unglück der Hindenburg in Lakehurst in Verbindung gebracht. Aeroux versucht diese Assoziation zu überwinden und Luftschiffe in der Gegenwart zu verankern.
Durch die gezielte, psychologisch inspirierte Gestaltung soll Sicherheit und Ruhe vermittelt werden, sollen spezifische Assoziationen geweckt werden, die weg führen von Bildern vergangener Tage eines brennenden Luftschiffs, um so Zeppeline als klimafreundlichere Alternative zum Flugzeug wieder ins Spiel zu bringen.
Aeroux ist ein hybrides Verkehrsmittel, dass in der Lage ist, sowohl Güter als auch Personen in verschiedenen Szenarien zu transportieren. Zeppeline bauchen keine befestigten Landebahnen oder Pisten. Regionen, die über Straßen schwer zugänglich sind, können so in den Warenhandel integriert werden. Gleichermaßen können aber auch Meschen in Regionen befördert werden, die durch Straßen oder Landebahnen nicht oder unzureichend erschlossen sind. Darüber hinaus kann Aeroux ein Ansatz sein die Unverträglichkeit von Fliegen und Klimaschutz aufzulösen.
Nicht zuletzt liegt in der gemächlichen Art der Bewegung ein besonderer Zauber. Reisen könnten einen neuen Charakter erhalten: durch die großen Fensterfronten und die geringe Flughöhe können Landschaften auf der Reise neu wahrgenommen werden, der Weg wird wieder Teil des Reisens.
Die Arbeit ist in erster Linie eine Auseinandersetzung mit der Form. Wie wirkt Form, wie lassen sich Assoziationen wecken, lenken, leiten. Wie kann technischer Anspruch, gesellschaftliche Bedingung, ökologisches Bewusstsein und nicht zuletzt Genuss in einem Objekt resultieren.
Digitale und analoge Fertigung spielen im Zuge der Arbeit ineinander. So entstand das Design der Gondel, nach ersten händischen Skizzen, digital. Das Model der Gondel wurde aus diesen Daten 3D gedruckt und die Darstellung der Traghülle ebenfalls auf Grundlage dieser Daten gelasert.
Aeroux möchte Lust auf alternatives Sehen, Denken und Handeln machen. Es gilt viel zu bewegen.
Wearable EEG has gained popularity in recent years driven by promising uses outside of clinics and research. The ubiquitous application of continuous EEG requires unobtrusive form-factors that are easily acceptable by the end-users. In this progression, wearable EEG systems have been moving from full scalp to forehead and recently to the ear. The aim of this study is to demonstrate that emerging ear-EEG provides similar impedance and signal properties as established forehead EEG. EEG data using eyes-open and closed alpha paradigm were acquired from ten healthy subjects using generic earpieces fitted with three custom-made electrodes and a forehead electrode (at Fpx) after impedance analysis. Inter-subject variability in in-ear electrode impedance ranged from 20 kΩ to 25 kΩ at 10 Hz. Signal quality was comparable with an SNR of 6 for in-ear and 8 for forehead electrodes. Alpha attenuation was significant during the eyes-open condition in all in-ear electrodes, and it followed the structure of power spectral density plots of forehead electrodes, with the Pearson correlation coefficient of 0.92 between in-ear locations ELE (Left Ear Superior) and ERE (Right Ear Superior) and forehead locations, Fp1 and Fp2, respectively. The results indicate that in-ear EEG is an unobtrusive alternative in terms of impedance, signal properties and information content to established forehead EEG.
Bacterial cellulose (BC) is a biopolymer produced by different microorganisms, but in biotechnological practice, Komagataeibacter xylinus is used. The micro- and nanofibrillar structure of BC, which forms many different-sized pores, creates prerequisites for the introduction of other polymers into it, including those synthesized by other microorganisms. The study aims to develop a cocultivation system of BC and prebiotic producers to obtain BC-based composite material with prebiotic activity. In this study, pullulan (PUL) was found to stimulate the growth of the probiotic strain Lactobacillus rhamnosus GG better than the other microbial polysaccharides gellan and xanthan. BC/PUL biocomposite with prebiotic properties was obtained by cocultivation of Komagataeibacter xylinus and Aureobasidium pullulans, BC and PUL producers respectively, on molasses medium. The inclusion of PUL in BC is proved gravimetrically by scanning electron microscopy and by Fourier transformed infrared spectroscopy. Cocultivation demonstrated a composite effect on the aggregation and binding of BC fibers, which led to a significant improvement in mechanical properties. The developed approach for “grafting” of prebiotic activity on BC allows preparation of environmentally friendly composites of better quality.
In order to realistically predict and optimize the actual performance of a concentrating solar power (CSP) plant sophisticated simulation models and methods are required. This paper presents a detailed dynamic simulation model for a Molten Salt Solar Tower (MST) system, which is capable of simulating transient operation including detailed startup and shutdown procedures including drainage and refill. For appropriate representation of the transient behavior of the receiver as well as replication of local bulk and surface temperatures a discretized receiver model based on a novel homogeneous two-phase (2P) flow modelling approach is implemented in Modelica Dymola®. This allows for reasonable representation of the very different hydraulic and thermal properties of molten salt versus air as well as the transition between both. This dynamic 2P receiver model is embedded in a comprehensive one-dimensional model of a commercial scale MST system and coupled with a transient receiver flux density distribution from raytracing based heliostat field simulation. This enables for detailed process prediction with reasonable computational effort, while providing data such as local salt film and wall temperatures, realistic control behavior as well as net performance of the overall system. Besides a model description, this paper presents some results of a validation as well as the simulation of a complete startup procedure. Finally, a study on numerical simulation performance and grid dependencies is presented and discussed.
Sleep spindles are neurophysiological phenomena that appear to be linked to memory formation and other functions of the central nervous system, and that can be observed in electroencephalographic recordings (EEG) during sleep. Manually identified spindle annotations in EEG recordings suffer from substantial intra- and inter-rater variability, even if raters have been highly trained, which reduces the reliability of spindle measures as a research and diagnostic tool. The Massive Online Data Annotation (MODA) project has recently addressed this problem by forming a consensus from multiple such rating experts, thus providing a corpus of spindle annotations of enhanced quality. Based on this dataset, we present a U-Net-type deep neural network model to automatically detect sleep spindles. Our model’s performance exceeds that of the state-of-the-art detector and of most experts in the MODA dataset. We observed improved detection accuracy in subjects of all ages, including older individuals whose spindles are particularly challenging to detect reliably. Our results underline the potential of automated methods to do repetitive cumbersome tasks with super-human performance.
Wo einst fast lückenlos Laubwälder wuchsen, steht heute nur noch ein Drittel der ursprünglichen Waldfläche. Echte Urwälder gibt es hier schon lange nicht mehr: Die Rede ist vom deutschen Wald.
Unsere Welt ist im Wandel. Auch in unseren heimischen Wäldern lassen sich die Einflüsse von Mensch und Klimawandel auf die Biodiversität beobachten.
Die illustrierte Publikation „Adapt or die“ lädt mit mehr als 80 großformatigen Artenportraits, Habitat-Kartierungen und gestalteten Themenklappenseiten zur Auseinandersetzung mit dem Wandel unserer heimischen Wälder ein. Dabei sensibilisiert sie für einen bewussteren Umgang mit Umwelt und Natur. Erweiterungen durch Augmented Reality bieten vereinzelt neben dem Printprodukt aktualisierbare Prognosen, digital und ressourcenschonend.
Das komplexe Ökosystem des Waldes reagiert empfindlich auf Veränderungen: Wer sich nicht anpassen kann, wird verschwinden.
aco : eine digitale Anwendung zur Verbesserung der Lebensqualität
von Neurodermitis-Patient:innen
(2022)
Neurodermitis hat in den letzten Jahrzehnten deutlich zugenommen. Etwa 10 bis 15 Prozent der Kinder und 2,5 bis 3,5 Prozent der Erwachsenen sind davon betroffen. Für sie stellen Auswirkungen der Hautkrankheit auf Körper und Psyche eine enorme Einschränkung der Lebensqualität dar.
Die App „aco“ möchte Neurodermitis-Patient:Innen dabei unterstützen, ihre Behandlung selbst in die Hand zu nehmen. Eine ganzheitliche Therapie umfasst eben nicht nur Fachpersonen, sondern auch Patient:Innen selbst. Durch eine regelmäßige Dokumentation ermöglicht die Anwendung eine aktive Auseinandersetzung mit der Krankheit. Triggerfaktoren werden ausgewertet und es wird Wissen über Behandlungsmöglichkeiten vermittelt. Zudem wird ein Austausch ermöglicht, der emotionale und praktische Unterstützung bieten soll. Damit möchte „aco“ Betroffenen eine Möglichkeit geben, das Ruder selbst in die Hand zu nehmen und leistet damit einen wichtigen Beitrag zur Therapie von Neurodermitis.
The fourth industrial revolution presents a multitude of challenges for industries, one of which being the increased flexibility required of manufacturing lines as a result of increased consumer demand for individualised products. One solution to tackle this challenge is the digital twin, more specifically the standardised model of a digital twin also known as the asset administration shell. The standardisation of an industry wide communications tool is a critical step in enabling inter-company operations. This paper discusses the current state of asset administration shells, the frameworks used to host them and their problems that need to be addressed. To tackle these issues, we propose an event-based server capable of drastically reducing response times between assets and asset administration shells and a multi-agent system used for the orchestration and deployment of the shells in the field.
Inhaltsverzeichnis - Bachelorarbeiten
1. Testamentsgestaltung bei Patchworkfamilien – Lösungsansätze für typische
Praxisprobleme unter Berücksichtigung der Interessenlagen der Parteien
- Ronja Bundrock 4 - 58
2. Die Haftung des AG-Vorstands gegenüber der Gesellschaft in unterneh-
mensinternen und -externen Krisen
- Nico Kremers 59 - 122
3. The Relationship of the Ex-Ante Uncertainty about the Value of a Stock
and its IPO Underpricing – An Analysis of the German Market
- Lennard Pankok 123 - 179
4. Attractiveness Bias in Venture Capital – An Analysis of Investor Decision
Making in “Die Höhle der Löwen”
- Theresa Maria Weisheit 180 - 242
Inhaltsverzeichnis – Masterarbeiten
Erhöhung der Energieautarkie in der Backbranche – Anwendung von bidi-
rektionalem Laden und dessen Auswirkungen auf die Geschäftsprozesse
und Informationssysteme
- Jasper Spoede 243 - 355
Inhaltsverzeichnis - Bachelorarbeiten
1. The impact of the EU non-financial reporting directive on sustainability reporting practices of DAX 30 companies
- Lene Christin Blöcker 4 - 29
2. Kurzarbeit als Krisenbewältigungsinstrument – Die arbeitsrechtlichen Voraussetzungen für die wirksame Einführung von Kurzarbeit
- Julia Esser 30 - 87
3. Die virtuelle Hauptversammlung der Aktiengesellschaft – Notlösung während der Corona-Pandemie oder dauerhafte Alternative?
- Pauline Hengstebeck 88 - 152
4. Die psychische Gesundheit am Arbeitsplatz – Aktuelle Problematik, Ursachenforschung, Folgen, rechtliche Rahmenbedingungen und geeignete Präventionsmaßnahmen aus Arbeitgebersicht
- Carolin Venrath 153 - 224
Inhaltsverzeichnis – Masterarbeiten
The influence of religion on the representation of women in politics
- Eva Scholtes 225 - 345
This study reviews the practice of brake tests in freight railways, which is time consuming and not suitable to detect certain failure types. Public incident reports are analysed to derive a reasonable brake test hardware and communication architecture, which aims to provide automatic brake tests at lower cost than current solutions. The proposed solutions relies exclusively on brake pipe and brake cylinder pressure sensors, a brake release position switch as well as radio communication via standard protocols. The approach is embedded in the Wagon 4.0 concept, which is a holistic approach to a smart freight wagon. The reduction of manual processes yields a strong incentive due to high savings in manual
labour and increased productivity.
Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here.
On the basis of bivariate data, assumed to be observations of independent copies of a random vector (S,N), we consider testing the hypothesis that the distribution of (S,N) belongs to the parametric class of distributions that arise with the compound Poisson exponential model. Typically, this model is used in stochastic hydrology, with N as the number of raindays, and S as total rainfall amount during a certain time period, or in actuarial science, with N as the number of losses, and S as total loss expenditure during a certain time period. The compound Poisson exponential model is characterized in the way that a specific transform associated with the distribution of (S,N) satisfies a certain differential equation. Mimicking the function part of this equation by substituting the empirical counterparts of the transform we obtain an expression the weighted integral of the square of which is used as test statistic. We deal with two variants of the latter, one of which being invariant under scale transformations of the S-part by fixed positive constants. Critical values are obtained by using a parametric bootstrap procedure. The asymptotic behavior of the tests is discussed. A simulation study demonstrates the performance of the tests in the finite sample case. The procedure is applied to rainfall data and to an actuarial dataset. A multivariate extension is also discussed.
A generalized shear-lag theory for fibres with variable radius is developed to analyse elastic fibre/matrix stress transfer. The theory accounts for the reinforcement of biological composites, such as soft tissue and bone tissue, as well as for the reinforcement of technical composite materials, such as fibre-reinforced polymers (FRP). The original shear-lag theory proposed by Cox in 1952 is generalized for fibres with variable radius and with symmetric and asymmetric ends. Analytical solutions are derived for the distribution of axial and interfacial shear stress in cylindrical and elliptical fibres, as well as conical and paraboloidal fibres with asymmetric ends. Additionally, the distribution of axial and interfacial shear stress for conical and paraboloidal fibres with symmetric ends are numerically predicted. The results are compared with solutions from axisymmetric finite element models. A parameter study is performed, to investigate the suitability of alternative fibre geometries for use in FRP.
An improved and convenient ninhydrin assay for aminoacylase activity measurements was developed using the commercial EZ Nin™ reagent. Alternative reagents from literature were also evaluated and compared. The addition of DMSO to the reagent enhanced the solubility of Ruhemann's purple (RP). Furthermore, we found that the use of a basic, aqueous buffer enhances stability of RP. An acidic protocol for the quantification of lysine was developed by addition of glacial acetic acid. The assay allows for parallel processing in a 96-well format with measurements microtiter plates.
[NON]HUMAN
(2022)
"[NON]HUMAN“ ist ein 3D-animierter Kurzfilm, der in einer Zombieapokalypse spielt und sich mit dem Thema der Menschlichkeit befasst. Welche Taten können gerechtfertigt werden und welche nicht? Die Handlungsmöglichkeiten der Menschen im Zuge des Ausbruchs eines neuen Virus werfen viele moralische Fragen auf, mit denen zwischen den Zeilen gerungen wird. Denn in diesem Film bestimmen sie Leben und Tod.
Das Ziel dieser Arbeit war es, eine simple Geschichte spannend zu erzählen, indem das Publikum durch eindrucksstarke Bilder gefesselt wird. Dabei eröffnen 3D-Animationen neue Möglichkeiten, die insbesondere in den Aufnahmen der zerstörten Stadt zur Geltung kommen. Diese Arbeit zeigt spielerisch, wie sich mit etwas technischem Know-How auch ohne großem Budget hochwertige Filme drehen lässt, indem man das Potential smart ausschöpft.
The recent amendment to the Ethernet physical layer known as the IEEE 802.3cg specification, allows to connect devices up to a distance of one kilometer and delivers a maximum of 60 watts of power over a twisted pair of wires. This new standard, also known as 10BASE-TIL, promises to overcome the limits of current physical layers used for field devices and bring them a step closer to Ethernet-based applications. The main advantage of 10BASE- TIL is that it can deliver power and data over the same line over a long distance, where traditional solutions (e.g., CAN, IO-Link, HART) fall short and cannot match its 10 Mbps bandwidth. Due to its recentness, IOBASE- TIL is still not integrated into field devices and it has been less than two years since silicon manufacturers released the first Ethernet-PHY chips. In this paper, we present a design proposal on how field devices could be integrated into a IOBASE-TIL smart switch that allows plug-and-play connectivity for sensors and actuators and is compliant with the Industry 4.0 vision. Instead of presenting a new field-level protocol for this work, we have decided to adopt the IO-Link specification which already includes a plug-and-play approach with features such as diagnosis and device configuration. The main objective of this work is to explore how field devices could be integrated into 10BASE-TIL Ethernet, its adaption with a well-known protocol, and its integration with Industry 4.0 technologies.
"I Was Here!"
(2022)
Die Menschheit erlebt aktuell Zeiten drastischen Wandels. Deswegen könnte es wohltun, einen Blick in die Vergangenheit zu werfen und sich darauf zu besinnen, wo die Menschen herkommen, wer sie waren und was seitdem bereits erreicht wurde.
In dieser Grafiknovelle wird ein kleiner Steinzeitjunge namens Muami begleitet, der vor 35.000 Jahren die Vergänglichkeit des Lebens kennenlernt. Im Verlauf des folgenden Jahres erfindet er die Selbstverewigung in der Höhlenmalerei.
Mit seiner Figur soll aufgezeigt werden, dass die frühen Europäer eben keine primitiven Halbaffen, sondern intelligente und außerdem zutiefst kreative Menschen waren. Trotz ihrer rauen Umwelt waren ihre Sorgen und Freuden den unseren gar nicht so unähnlich. „I Was Here!“ ist ein Versuch, ein authentisches Porträt jener Menschen zu schaffen und dabei ihrer Welt, ihrem Leben und ihrer Kunst gerecht zu werden.