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Silicon photonic micro-ring resonators (MRR) developed on the silicon-on-insulator (SOI) platform, owing to their high sensitivity and small footprint, show great potential for many chemical and biological sensing applications such as label-free detection in environmental monitoring, biomedical engineering, and food analysis. In this tutorial, we provide the theoretical background and give design guidelines for SOI-based MRR as well as examples of surface functionalization procedures for label-free detection of molecules.
After introducing the advantages and perspectives of MRR, fundamentals of MRR are described in detail, followed by an introduction to the fabrication methods, which are based on a complementary metal-oxide semiconductor (CMOS) technology. Optimization of MRR for chemical and biological sensing is provided, with special emphasis on the optimization of waveguide geometry. At this point, the difference between chemical bulk sensing and label-free surface sensing is explained, and definitions like waveguide sensitivity, ring sensitivity, overall sensitivity as well as the limit of detection (LoD) of MRR are introduced. Further, we show and explain chemical bulk sensing of sodium chloride (NaCl) in water and provide a recipe for label-free surface sensing.
Three building blocks have been designed to chemically link to a gold surface and vertically self-assemble through thymine–adenine hydrogen bonds. Starting from these building blocks, two different films were engineered on gold surface. Film 1 consists of adenine linked to lipoic acid (Lipo–A) to covalently bind to the gold surface, and ZnTPP linked to a thymine (T–ZnTPP). Film 2 has an additional noncovalently linked layer: a helical undecapeptide analogue of the trichogin GA IV peptide, in which four glycines were replaced by four lysines to favor a helical conformation and reduce flexibility and the two extremities were functionalized with thymine and adenine to enable Lipo–A and T–ZnTPP binding, respectively. These films were characterized by electrochemical and spectroscopic techniques, and were very stable over time and when in contact with solution. Under illumination, they could generate current with higher efficiency than similar previously described systems.
Both, from an environmental perspective and with respect to road traffic flow quality, planning so-called green waves along major road axes is a well-established target for traffic engineers. For one-way road axes (e.g. the Avenues in Manhattan), this is a trivial downstream task. For bidirectional arterials, the well-known necessary condition for establishing a green wave in both direction is that the driving times between two subsequent crossings must be an integer multiple of half of the cycle time of the signal programs at the nodes.
In this paper, we propose an integer linear optimization model to establish fixed-time green waves in both directions that are as long and as wide as possible, even in the situation where the driving time condition is not fulfilled. In particular, we are considering an arterial along whose nodes separate left-turn signal groups are realized.
In our computational results, we provide examples which illustrate that allowing for selecting among different strategies for the left-turn phases is beneficial. Moreover, we show that there is always a solution with green waves in both directions that are as long and as wide as possible, where absolute priority is put on just one direction. Only when considering prioritized parts of a green band (e.g. some first few seconds), then an ideal green wave into one direction can provide suboptimal quality compared to optimizing both directions together.
The Ring Never Relieves
(2021)
Regarding the disposition of metro lines in order to recover from delays, in the literature there can be found two branches of contributions: On the one hand, there are descriptions of response rules such as expressing (also referred to as skip stop), holding and short-turning together with studies in what situation to apply which of them. On the other hand, there are fully-automated optimization models which make use of any possible driving and routing options, according to some specified objective function.
To the best of our knowledge, we are not aware of any study that puts its focus specifically on ring lines (also known as circle or loop lines). Yet, in the absence in particular of more or less 'natural' time buffers in turnaround activities in the endpoints, the operation of a circle line is particularly challenging.
In this spirit, we are collecting response rules that are applicable especially for circle lines. We sketch their impacts on the passengers’ travel experience as well as on the resource schedules for the rolling stock and staff (train drivers). For selected response rules, we provide illustrative drawings.
Moreover, we present the answers that experts of eleven metro networks that are operating circle lines were pointing to us during interviews. It turns out that despite the limited possibilities along circle lines there is a broad repertoire of response action that is taken on a regular basis – but also that some standard general response rule (expressing) is almost never applied in practice.
Today, academic researchers benefit from the changes driven by digital technologies and the enormous growth of knowledge and data, on globalisation, enlargement of the scientific community, and the linkage between different scientific communities and the society. To fully benefit from this development, however, information needs to be shared openly and transparently. Digitalisation plays a major role here because it permeates all areas of business, science and society and is one of the key drivers for innovation and international cooperation. To address the resulting opportunities, the EU promotes the development and use of collaborative ways to produce and share knowledge and data as early as possible in the research process, but also to appropriately secure results with the European strategy for Open Science (OS). It is now widely recognised that making research results more accessible to all societal actors contributes to more effective and efficient science; it also serves as a boost for innovation in the public and private sectors. However for research data to be findable, accessible, interoperable and reusable the use of standards is essential. At the metadata level, considerable efforts in standardisation have already been made (e.g. Data Management Plan and FAIR Principle etc.), whereas in context with the raw data these fundamental efforts are still fragmented and in some cases completely missing. The CHARME consortium, funded by the European Cooperation in Science and Technology (COST) Agency, has identified needs and gaps in the field of standardisation in the life sciences and also discussed potential hurdles for implementation of standards in current practice. Here, the authors suggest four measures in response to current challenges to ensure a high quality of life science research data and their re-usability for research and innovation.
Old wine into old wineskins
(2021)
Wildau ist für über einhundert Jahren als Industriestandort vor den Toren Berlins entstanden. Der Südzipfel dieses industriellen Areals, auf dem Lokomotiven hergestellt und später der Schwermaschinenbau die Anlagen nachnutzte, bildet heute den Hochschulcampus der TH Wildau. Nach der politischen Wende wurden aus ehemaligen Fabrikhallen Lehr- und Forschungsgebäude mit Hörsälen, Büros, Laboren und einer Bibliothek. Mit der Umwidmung einer ehemaligen Verladehalle in eine Bibliothek geht ein besonderer qualitativer Schritt einher, sowohl in der Architekur als auch im Service. Die Einbettung der Bibliothek in dieses denkmalgeschützte Ensemble liefert auf besondere Weise Identität und Nachhaltigkeit.
Hauptaufgabe der staatlichen Hochschulen ist es, Wissen zu schaffen und nutzbringend in die Gesellschaft, insb. in Wirtschaft und Verwaltung zu transferieren. Dies geschieht traditionell durch Forschung und ihre Publikation sowie durch Lehre und den Ausstoß von Absolventen. In den letzten Jahren wird von der Politik zunehmend auch die sog. „Dritte Mission“ (Kooperation, Technologietransfer etc.) von der Wissenschaft eingefordert. Alle drei Transferwege werden jedoch gleichzeitig auch von der Politik behindert. Der Artikel greift drei Beispiele hierfür heraus: Die Untätigkeit gegenüber dem Aufbau einer privatwirtschaftlichen Bezahlschranke für die öffentliche Nutzung staatlich finanzierter digitaler Publikationen, die aktive Förderung des Aufbaus einer Sprachbarriere zwischen Landessprache und Wissenschaftsbetrieb und das Versäumnis, die freie online-Publikation aller Abschlussarbeiten zur Erlangung wissenschaftlicher Grade sicherzustellen
Ridepooling stellt eine viel diskutierte Mobilitätsform dar. Ad-hoc und in der Regel von mobilen Endgeräten übermittelte Fahrtwünsche einzelner Fahrgäste werden bedarfsgesteuert, fahrplanfrei und vollflexibel zu möglichst effizienten, geteilten Fahrten gebündelt, welche im Regelfall mit Vans oder Kleinbussen durchgeführt werden. Sowohl aus Betreibersicht als auch insbesondere aus der Sicht von Genehmigungsbehörden stellt sich dabei die Frage nach der betrieblichen Effizienz von Ridepooling-Systemen, welche nicht zuletzt für die Bewertung der Konformität zu öffentlichen Verkehrsinteressen, speziell einer effizienten Nutzung öffentlicher Verkehrsinfrastruktur, relevant sein können. In diesem Zuge werden teilweise auch bereits Aspekte wie Umwegfaktor, Besetzungsgrad und Leerkilometeranteil diskutiert. Im vorliegenden Beitrag werden diese Aspekte als ein Teilergebnis der Arbeit des FGSV-Arbeitskreises 1.6.1 "Verkehrliche Anforderungen an Ridepooling-Systeme" zu einem Kennzahlensystem zusammengefügt, die vollständigen Ausführungen finden sich dabei in Liebchen et al. (2020).
Konventionelle Fertigungsstrategien werden künftig zunehmend durch komplexe cyberphysische Produktionssysteme (CPPS) ersetzt. Es entstehen durchgehend verbundene Wertschöpfungsnetzwerke mit großer Informationsdichte, die den Menschen mit einer signifikant gestiegenen Datenmenge konfrontieren, auf deren Basis er agieren muss. Daher nimmt die Mensch-Maschine-Schnittstelle einen wichtigen Stellenwert innerhalb des Produktionsprozesses ein, wobei sich neuartige Visualisierungsverfahren wie Augmented Reality (AR) vielversprechend zeigen. Für entsprechende Anwendungen bedarf es einer durchgängigen Kommunikation aus dem Feld bis hin zur Applikation. Der Artikel beschreibt, wie existierende Kommunikationsstandards dafür nutzbar gemacht werden können und zeigt eine beispielhafte Umsetzung. Zudem wird eine Kommunikationsarchitektur vorgeschlagen, die auf Grundlage der Verwaltungsschale den interoperablen Informationsaustausch zwischen physischen und virtuellen Entitäten ermöglicht.
Helium implanted tungsten-titanium ODS alloys are investigated using positron annihilation spectroscopy and nanoindentation. Titanium reduces the brittleness of the tungsten alloy, which is manufactured by mechanical alloying. The addition of Y2O3 nanoparticles increases the mechanical properties at elevated temperature and enhances irradiation resistance. Helium ion implantation was applied to simulate irradiation effects on these materials. The irradiation was performed using a 500 kV He ion implanter at fluences around 5 × 1015 cm−2 for a series of samples both at room temperature and at 600 °C. The microstructure and mechanical properties of the pristine and irradiated W-Ti-ODS alloy are compared with respect to the titanium and Y2O3 content. Radiation damage is studied by positron annihilation spectroscopy analyzing the lifetime and the Doppler broadening. Three types of helium-vacancy defects were detected after helium irradiation in the W-Ti-ODS alloy: small defects with high helium-to-vacancy ratio (low S parameter) for room temperature irradiation, larger open volume defects with low helium-to-vacancy ratio (high S parameter) at the surface and He-vacancy complexes pinned at nanoparticles deeper in the material for implantation at 600 °C. Defect induced hardness was studied by nanoindentation. A drastic hardness increase is observed after He ion irradiation both for room temperature and elevated irradiation temperature of 600 °C. The Ti alloyed tungsten-ODS is more affected by the hardness increase after irradiation compared to the pure W-ODS alloy.