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- PublikationA novel measurement system for unattended, in situ characterization of carbonaceous aerosols(Copernicus, 22.12.2023) Keller, Alejandro; Specht, Patrick; Steigmeier, Peter; Weingartner, Ernest [in: Aerosol Research]Carbonaceous aerosol is a relevant constituent of the atmosphere in terms of climate and health impacts. Nevertheless, measuring this component poses many challenges. There is currently no simple and sensitive commercial technique that can reliably capture its totality in an unattended manner, with minimal user intervention, for extended periods of time. To address this issue we have developed the fast thermal carbon totalizator (FATCAT). Our system captures an aerosol sample on a rigid metallic filter and subsequently analyses it by rapidly heating the filter directly, through induction, to a temperature around 800°C. The carbon in the filter is oxidized and quantified as CO2 in order to establish the total carbon (TC) content of the sample. The metallic filter is robust, which solves filter displacement or leakage problems, and does not require a frequent replacement like other measurement techniques. The limit of detection of our system using the 3σ criterion is TC =0.19 µg-C (micrograms of carbon). This translates to an average ambient concentration of TC =0.32 µg-C m^−3 and TC =0.16 µg-C m^−3 for sampling interval of 1 or 2 h respectively using a sampling flow rate of 10 L min^−1. We present a series of measurements using a controlled, well-defined propane flame aerosol as well as wood-burning emissions using two different wood-burning stoves. Furthermore, we complement these measurements by coating the particles with secondary organic matter by means of an oxidation flow reactor. Our device shows a good correlation (correlation coefficient, R^2>0.99) with well-established techniques, like mass measurements by means of a tapered element oscillating microbalance and TC measurements by means of thermal–optical transmittance analysis. Furthermore, the homogeneous fast-heating of the filter produces fast thermograms. This is a new feature that, to our knowledge, is exclusive of our system. The fast thermograms contain information regarding the volatility and refractoriness of the sample without imposing an artificial fraction separation like other measurement methods. Different aerosol components, like wood-burning emissions, soot from the propane flame and secondary organic matter, create diverse identifiable patterns.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationQuantum logical controlled-NOT gate in a lithium niobate-on-insulator photonic quantum walk(Institute of Physics Publishing, 17.11.2023) Chapman, Robert J; Häusler, Samuel; Finco, Giovanni; Kaufmann, Fabian; Grange, Rachel [in: Quantum Science and Technology]The two-qubit controlled-NOT gate is one of the central entangling operations in quantum information technology. The controlled-NOT gate for single photon qubits is normally realized as a network of five individual beamsplitters on six optical modes. Quantum walks (QWs) are an alternative photonic architecture involving arrays of coupled waveguides, which have been successful for investigating condensed matter physics, however, have not yet been applied to quantum logical operations. Here, we engineer the tight-binding Hamiltonian of an array of lithium niobate-on-insulator waveguides to experimentally demonstrate the two-qubit controlled-NOT gate in a QW. We measure the two-qubit transfer matrix with 0.938 ± 0.003 fidelity, and we use the gate to generate entangled qubits with 0.945 ± 0.002 fidelity by preparing the control photon in a superposition state. Our results highlight a new application for QWs that use a compact multi-mode interaction region to realize large multi-component quantum circuits.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationMultiscale characterisation of staple carbon fibre-reinforced polymers(MDPI, 06.11.2023) Zweifel, Lucian; Kupski, Julian; Dransfeld, Clemens; Caglar, Baris; Baz, Stephan; Cessario, Damian; Gresser, Götz T.; Brauner, Christian [in: Journal of Composites Science]The aim of this study was to characterise the microstructural organisation of staple carbon fibre-reinforced polymer composites and to investigate their mechanical properties. Conventionally, fibre-reinforced materials are manufactured using continuous fibres. However, discontinuous fibres are crucial for developing sustainable structural second-life applications. Specifically, aligning staple fibres into yarn or tape-like structures enables similar usage to continuous fibre-based products. Understanding the effects of fibre orientation, fibre length, and compaction on mechanical performance can facilitate the fibres’ use as standard engineering materials. This study employed methods ranging from microscale to macroscale, such as image analysis, X-ray computed tomography, and mechanical testing, to quantify the microstructural organisations resulting from different alignment processing methods. These results were compared with the results of mechanical tests to validate and comprehend the relationship between fibre alignment and strength. The results show a significant influence of alignment on fibre orientation distribution, fibre volume fraction, tortuosity, and mechanical properties. Furthermore, different characteristics of the staple fibre tapes were identified and attributed to kinematic effects during movement of the sliver alignment unit, resulting in varying tape thicknesses and fuzzy surfaces.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationInteractive use-case generation tool for functional REST API testing(Hochschule für Technik FHNW, 18.08.2023) Volken, Jonas; Leu, Benjamin; Kropp, Martin; Affolter, Fabian; Tesitifi GmbHSoftware is an integral part of any business, which makes the significance of high-quality software in today’s digital age undeniable. However, despite the advancements in software testing, challenges persist in efficiently planning, generating, and executing test cases, particularly for REST API-based applications. This project addresses the issue by developing a sequence generator tool that enables testers to effortlessly create and execute sequences of requests, streamlining the creation of comprehensive test scenarios. By simplifying the process of connecting response values to subsequent request values, the software seeks to maximize test coverage, improve test quality, and enable testers to focus more on software quality enhancement than the efforts of test construction. The client for this project is Testifi GmbH, a company dedicated to enhancing software delivery processes through DevOps integrations and AI-automated quality assurance solutions. The main focus of the project was to find out if the test quality increased by using the sequence generator tool due to more edge cases and more complex scenarios being tested compared to manual API testing, as well as showing if the efficiency improvement can be measured in reduced amount of time necessary for creation sequences. To answer these questions and develop an application that offers value for Testifi GmbH, a literature review was conducted on the subjects of basic user interface design and user experience concepts for advanced users. Based on the findings, the user interface of the application was outlined and the software implemented. During development and with the finished product, multiple sets of user tests were conducted with users experienced in working with APIs, to improve the design and software during development, and to gain insights about the effectiveness of the final product. Those tests showed that the main goals of the project could be reached by demonstrating a considerable amount of time saved by using the application, while also outperforming manual testing methods in efficiency and ease of use. Key features like the linking of response values to subsequent request values and the suggestion of such links based on Testifi’s Pulse Artificial intelligence (AI) as well as previously created sequences were well received by testers and customer. The literature review also proved to be very valuable as users praised the straightforward design, while never missing any important data. When Testifi GmbH integrates the end product in their pulse workflow, its ability to create sequences easily and intuitively as well as the potential of the additional link suggestions created by the tool to be used in improving the Pulse AI will be indispensable.11 - Studentische Arbeit
- PublikationTailored flexibility in inherently brittle epoxy-based composites through gradient interphase formation with bio-based thermoplastic elastomer grades(Elsevier, 05.07.2023) Zweifel, Lucian; Kupski, Julian; Brauner, Christian [in: Composites Part A: Applied Science and Manufacturing]This study focuses on tailoring elastic behaviour in an inherently brittle epoxy-based fibre-reinforced composite material formed through a gradient interphase with a bio-based thermoplastic elastomer. The fast-curing epoxy Araldite LY3585/Aradur 3475 was tested with two bio-based Pebax block copolymer grades. First, the interphase was characterised via optical hot-stage microscopy and Raman spectroscopy. The analysis unveiled pronounced diffusion followed by a reaction-induced phase separation, which led to the formation of an interphase with a thickness exceeding 200 μm at the temperatures associated with the curing process. Second, composite laminates were fabricated through a combined process of fused filament fabrication and vacuum infusion, incorporating a flexible domain with variable stiffness properties. The material architecture exhibited brittle-to-ductile behaviour at the micrometre scale, with tailored flexible response under bending and stiff behaviour in tension. Consequently, the study anticipates using multi-scale toughened material structures for more efficient generative design concepts.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationTätigkeitsbericht 2022(Institut für Automation, Hochschule für Technik FHNW, 04/2023) Isler, Rolf; Gabrys, JadwigaTätigkeitsberichte über aktuelle Forschungsobjekte, die im Institut im Jahr 2022 bearbeitet wurden05 - Forschungs- oder Arbeitsbericht
- PublikationMaintenance and evolution of large scale software systems – Business, dev & ops challenges(10.02.2023) Rüegger, Janick; Kropp, MartinEven in the time of agile software development and devOps, maintenance and evolution of large-scale software systems remain challenging. This is not only caused by technical debt, but is heavily caused by lost knowledge, high complexity of micro-service architectures, difficult requirements management, not available documentation, and the complexity of communication among and coordination of the many stakeholders. In our session we will talk about the challenges we identified in our study and present new approaches to address these challenges.06 - Präsentation
- PublikationWaste self-reporting for software development productivity improvement(Springer, 2023) Sallin, Marc; Kropp, Martin; Anslow, Craig; Biddle, Robert; Stettina, Christoph J.; Garbajosa, Juan; Kruchten, Philippe [in: Agile processes in software engineering and extreme programming]Little research has been done on enabling software development teams to self-report waste to assist in productivity improvement. This study created a waste categorization and survey for teams to identify and quantify wasteful activities. Developers from a Swiss company used the survey for three weeks. Participants found the survey helpful for identifying waste but there was little evidence that self-reported waste correlated with improved performance.04B - Beitrag Konferenzschrift
- PublikationWaveguide based passively demodulated photothermal interferometer for light absorption measurements of trace substances(Optica Publishing Group, 2023) Visser, Bradley; Bilal, Jonas; Flöry, Nikolaus; Wipf, Manuela; Steigmeier, Peter; Rüggeberg, Tobias; Betschon, Felix; Weingartner, Ernest [in: Applied Optics]01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationFused filament fabrication of bio-based polyether-block-amide polymers (PEBAX) and their related properties(MDPI, 23.11.2022) Schär, Matthias; Zweifel, Lucian; Arslan, Delal; Grieder, Stefan; Maurer, Christoph; Brauner, Christian [in: Polymers]This paper describes the application of poly(ether-block-amide) polymers, so-called Pebax, in fused filament fabrication (FFF). Pebax® is a thermoplastic elastomer (TPE), a copolymer based on rigid polyamide and soft polyether blocks. By variation of the blocks, unique properties such as soft or rigid behaviour are tailored without additional additives and plasticisers. Pebax®Rnew® polyamide blocks are bio-based and made from castor beans that allow the design of sustainable applications. In this study, two types of Pebax were selected, processing parameters were characterised, filaments were extruded and applied to FFF printing, and the final mechanical characteristics were determined. Both types were suitable for FFF processing with improved process stability due to less shear thinning and good mechanical performance. The connection strength between the grades was also described in the design context for complex parts with tailored soft or hard regions. Combining the two materials in one design is a promising concept, and the adhesion strength is close to the strength in the Z-direction of the flexible Pebax®Rnew®35R53 grade.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationMeasurement methods for RWB Emissions: what should be considered for a future standard?(09.11.2022) Keller, Alejandro06 - Präsentation
- PublikationEinblick. Nach mehr als zwei Jahren Forschung gibt es Neuigkeiten zur Wirkung prismatischer Korrekturen beim Lesen(Galledia, 10/2022) Joss, Joëlle; Jainta, Stephanie [in: Schweizer Optiker]01B - Beitrag in Magazin oder Zeitung
- PublikationMakro- und Mikrokunststoffuntersuchungen in Kompost mittels hyperspektraler Bildgebung(Hochschule für Technik FHNW, 15.09.2022) Mandaliev, Petar; Schreiber, Raffael Michael; Mandaliev, Petar; Epyxs GmbHIm vorhergehenden Projekt EUT-P5bb-RS-HS20 wurde die Tauglichkeit von hyperspektraler Bildgebung zur Identifikation von Mikro- und Makroplastik in Kompost untersucht. Dafür wurde ein neuronales Netzwerk mit hyperspektralen Daten von Referenzkunststoffen der Typen Polyethylen (PE), Polystyrol (PS), Polypropylen (PP) und Polyethylenterephthalat (PET) trainiert. Mit diesem Netzwerk konnten Körner der Referenzkunststoffe erfolgreich in Kompostproben erkannt werden. Das Netzwerk konnte die meisten Alltagskunststoffe aber nicht korrekt identifizieren. Ziel dieser Arbeit war es also zu untersuchen, ob sich die Methode aus dem vorhergehenden Projekt auch zur Erkennung von Alltagskunststoffen aus der Kompostanlage eignet. Daher wurden solche Kunststoffe analysiert, um die Auswirkungen von Umwelteinflüssen auf die hyperspektrale Bildgebung zu untersuchen und mögliche Preprocessing-Schritte zur Kompensation zu definieren.11 - Studentische Arbeit
- PublikationThe organic coating unit, an all-in-one system for reproducible generation of secondary organic aerosol(06.09.2022) Keller, Alejandro; Kalbermatter, Daniel; Specht, Patrick; Steigmeier, Peter; Wolfer, Katherin; Resch, Julian; Kalberer, Markus; Hammer, Tobias; Vasilatou, Konstantina06 - Präsentation
- PublikationThe organic coating unit, an all-in-one system for reproducible generation of secondary organic matter aerosol(Taylor & Francis, 18.08.2022) Keller, Alejandro; Kalbermatter, Daniel M.; Wolfer, Kate; Specht, Patrick; Steigmeier, Peter; Resch, Julian; Kalberer, Markus; Hammer, Tobias; Vasilatou, Konstantina [in: Aerosol Science and Technology]We report on a novel automated oxidation flow reactor to generate a wide variety of organic aerosol samples. The instrument is equipped with a humidifier, a dosing system for volatile organic precursors and an oxidation flow reactor (OFR) for generation of secondary organic matter (SOM). The instrument, known as organic coating unit (OCU), can produce homogeneously nucleated SOM particles or, used in combination with a standard combustion generator (e.g., a diffusion flame soot generator or any other seed particle), particles coated with a controlled amount of SOM. The physical and chemical properties of the generated particles can be controlled in a simple manner by selecting through a touch-screen target values for parameters, such as organic gaseous precursor concentration, humidity, and UV (ultraviolet) light intensity. Parameters and measured quantities are automatically stored in text files for easy export and analysis. Furthermore, we provide stable operation conditions and characterize the physicochemical properties of the generated aerosols with an array of methods, including transmission electron microscopy (TEM), thermal-optical analysis and liquid chromatography coupled with mass spectrometry (LC-MS). This all-in-one instrument is robust, compact, portable, and user-friendly, making it ideal for laboratory or field-based aerosol studies.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationResponses of reconstituted human bronchial epithelia from normal and health-compromised donors to non-volatile particulate matter emissions from an aircraft turbofan engine(Elsevier, 15.08.2022) Delaval, Mathilde N.; Jonsdottir, Hulda R.; Leni, Zaira; Keller, Alejandro; Brem, Benjamin T.; Siegerist, Frithjof; Schönenberger, David; Durdina, Lukas; Elser, Miriam; Salathe, Matthias; Baumlin, Nathalie; Lobo, Prem; Burtscher, Heinz; Liati, Anthi; Geiser, Marianne [in: Environmental Pollution]Health effects of particulate matter (PM) from aircraft engines have not been adequately studied since controlled laboratory studies reflecting realistic conditions regarding aerosols, target tissue, particle exposure and deposited particle dose are logistically challenging. Due to the important contributions of aircraft engine emissions to air pollution, we employed a unique experimental setup to deposit exhaust particles directly from an aircraft engine onto reconstituted human bronchial epithelia (HBE) at air-liquid interface under conditions similar to in vivo airways to mimic realistic human exposure. The toxicity of non-volatile PM (nvPM) from a CFM56-7B26 aircraft engine was evaluated under realistic engine conditions by sampling and exposing HBE derived from donors of normal and compromised health status to exhaust for 1 h followed by biomarker analysis 24 h post exposure. Particle deposition varied depending on the engine thrust levels with 85% thrust producing the highest nvPM mass and number emissions with estimated surface deposition of 3.17 × 109 particles cm−2 or 337.1 ng cm−2. Transient increase in cytotoxicity was observed after exposure to nvPM in epithelia derived from a normal donor as well as a decrease in the secretion of interleukin 6 and monocyte chemotactic protein 1. Non-replicated multiple exposures of epithelia derived from a normal donor to nvPM primarily led to a pro-inflammatory response, while both cytotoxicity and oxidative stress induction remained unaffected. This raises concerns for the long-term implications of aircraft nvPM for human pulmonary health, especially in occupational settings.01A - Beitrag in wissenschaftlicher Zeitschrift
- PublikationRelevanz verschiedener Einflussfaktoren auf den Fremdstoffgehalt von Grüngut aus Haushalten(Hochschule für Technik FHNW, 06.08.2022) Mandaliev, Petar; Dietiker, Raphael; Mandaliev, Petar; Biomasse SuisseDer Grundgedanke der Kreislaufwirtschaft fördert die getrennte Sammlung von biogenen Ab-fällen. In der Schweiz ist es gesetzlich gefordert, diese Abfälle zu sammeln und zu verwerten. Vergärungs- und Kompostieranlagen produzieren organischen Recyclingdünger, der in der Landwirtschaft und im Gartenbau eingesetzt werden kann. Bei der Vergärung kann zusätzlich erneuerbare Energie in Form von Gas oder Strom hergestellt werden. Als grösster Input für die Verwertungsanlagen sind national die kommunalen Sammeldienste verantwortlich. Die bi-ogenen Abfälle aus privaten Haushalten machen dabei einen Grossteil aus. Der Fremdstoff-anteil in den Produkten aus Vergärungs- und Kompostierprozessen stellt ein Problem für An-lagenbetreiber und Natur dar. Ein Teil der Abfallentsorgerinnen und Abfallentsorger versteht nicht, dass mit der Fremdstoffentfernung im Grüngut grosse manuelle und technischen Her-ausforderungen einher gehen. Sie entsorgen anstelle von biogenem Material Fremdstoffe wie Kunststoffe etc. im grünen Kübel. Trotz der Entwicklung der Digitalisierung und Automatisie-rung werden im Alltag der Anlagenbetreiber nach wie vor Fremdstoffe in biogenen Abfällen von Hand aussortiert. Auf diese Weise kann ein Weiterleiten von Fremdstoffanteilen in die nachfolgenden Prozesse nicht absolut ausgeschlossen werden. Kompostier- sowie Vergä-rungsanlagen sind daher auf einen möglichst sauberen Input angewiesen.11 - Studentische Arbeit
- PublikationRelating asthenopic symptoms to optometric measures and parameters of binocular vision(08/2022) Joss, Joëlle; Jainta, StephanieAsthenopic symptoms are related to heterophoria and problems of binocular vision. In a recent paper, we showed that vergence drift and fixation durations are related to symptoms (CISS-questionnaire), but optometric measures such as heterophoria, vergence or accommodative facility, AC/A-ratio or NPC did not significantly add to the explained variance of asthenopia. We re-analysed our data, in which binocular eye movements were recorded (EyeLink II) for 64 participants, and linear regression analyses related all parameters of binocular coordination (objective heterophoria, vergence drift, saccade disconjugacy, fixation disparity and fixation duration), and the above-mentioned optometric tests to 4 symptoms factors (eye comfort, reading process, image quality and fatigue), which we identified by a factor analysis of the CISS-questionnaire. Objective heterophoria and fixation duration predicted 20% of the variance in symptoms concerning the reading process (factor 2). Furthermore, fixation duration seems to be slightly, but not significantly, related to symptoms addressing fatigue (factor 4), whereas optometric tests are not significantly related to any asthenopia factor. Overall, objective measures during reading relate to asthenopic symptoms, however the lack of asthenopic symptoms prediction by daily optometric parameters is still unexplained. Therefore, further research is needed to find out suited optometric parameters to infer asthenopic symptoms.06 - Präsentation
- PublikationFirst demonstration of a post-quantum key-exchange with a nanosatellite(08/2022) Burkhardt, Simon Martin; Meier, Willi; Wildfeuer, Christoph; Reezwana, Ayesha; Islam, Tanvirul; Ling, Alexander [in: Proceedings of the Small Satellite Conference]We demonstrate a post-quantum key-exchange with the nanosatellite SpooQy-1 in low Earth orbit using Kyber-512, a lattice-based key-encapsulation mechanism and a round three finalist in the NIST PQC standardization process. Our firmware solution runs on an on-board computer that is based on the Atmel AVR32 RISC microcontroller, a widely used platform for nanosatellites. We uploaded the new firmware with a 436.2 MHz UHF link using the CubeSat Space Protocol (CSP) and performed the steps of the key exchange in several passes over Switzerland. The shared secret key generated in this experiment could potentially be used to encrypt RF links with AES-256. This implementation demonstrates the feasibility of a quantum-safe authenticated key-exchange and encryption system on SWaP constrained nanosatellites.04B - Beitrag Konferenzschrift
- PublikationThe organic coating unit, an all-in-one system for reproducible generation of secondary organic aerosol(22.06.2022) Keller, Alejandro; Specht, Patrick; Steigmeier, Peter; Kalbermatter, Daniel; Hammer, Tobias; Vasilatou, Konstantina; Wolfer, Kate; Resch, Julian; Kalberer, Markus06 - Präsentation