@article{PangerlMuellerRuecketal., author = {Pangerl, Jonas and M{\"u}ller, Max and R{\"u}ck, Thomas and Weigl, Stefan and Bierl, Rudolf}, title = {Characterizing a sensitive compact mid-infrared photoacoustic sensor for methane, ethane and acetylene detection considering changing ambient parameters and bulk composition (N2, O2 and H2O)}, series = {Sensors and Actuators B: Chemical}, volume = {352,1}, journal = {Sensors and Actuators B: Chemical}, publisher = {Elsevier}, doi = {10.1016/j.snb.2021.130962}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-25868}, pages = {1 -- 12}, abstract = {We present a sensitive and compact interband cascade laser (ICL) based photoacoustic setup for the detection of gaseous hydrocarbons and discuss its applicability towards trace gas analysis. We investigated the performance of the sensor for trace concentrations of methane, ethane and acetylene diluted in nitrogen. The excitation of methane and ethane was accomplished using one tunable diode laser, covering a range from 3360 to 3372 nm, which was replaced by a separate ICL at 3025 nm for acetylene detection. The influence of ambient parameters such as temperature, flow rate and pressure as well as potential cross-sensitivities towards O2 and H2O have been examined in terms of methane and acetylene detection. A series of simulations proved several of these influences to be attributed to relaxation effects. With a 3σ limit of detection (LoD) of 6.8 parts per billion (ppbV) in case of methane, 2.3 ppbV regarding ethane and 3.6 ppbV in terms of acetylene, the sensor demonstrates a great potential for applications in the field of trace gas analysis.}, language = {en} } @article{HerrmannBrunnerLaubmeier, author = {Herrmann, Frank and Brunner, Stephan and Laubmeier, Franz}, title = {Optimierung des Arbeitsablaufes von Lieferantenanfragen unter Entwicklung eines Webportals und weiteren Neuerungen im ERP-System FactWork}, series = {Anwendungen und Konzepte der Wirtschaftsinformatik online}, volume = {13}, journal = {Anwendungen und Konzepte der Wirtschaftsinformatik online}, publisher = {AKWI}, doi = {10.26034/lu.akwi.2021.3304}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-30626}, pages = {19 -- 26}, abstract = {Effiziente Arbeitsabl{\"a}ufe sind f{\"u}r profitable Unternehmen von zentraler Natur. ERP-Systeme k{\"o}nnen betreffenden Firmen dahingehend helfen, besagte Arbeitsabl{\"a}ufe entsprechend abzubilden und nach M{\"o}glichkeit auch zu automatisieren. In dieser Arbeit sollen die notwendigen Schritte zur Bearbeitung einer Lieferantenanfrage prim{\"a}r durch eine Weboberfl{\"a}che zur automatisierten R{\"u}ckf{\"u}hrung eingehender Angebote, sowie weiteren Verbesserungen, optimiert werden, was eine Erh{\"o}hung der Produktivit{\"a}t, eine Verminderung des Zeitaufwandes, und damit auch eine Reduzierung der Personalkosten zur Folge hat.}, language = {de} } @article{HerrmannKirschnerKleinertetal., author = {Herrmann, Frank and Kirschner, Jan Michael and Kleinert, Thomas and Fritzsche, Harald}, title = {Big Data im Bereich der technischen Sauberkeit}, series = {Anwendungen und Konzepte der Wirtschaftsinformatik (AKWI)}, journal = {Anwendungen und Konzepte der Wirtschaftsinformatik (AKWI)}, number = {13}, publisher = {Hochschule}, address = {Luzern}, issn = {2296-4592}, doi = {10.26034/lu.akwi.2021.3296}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-30550}, pages = {34 -- 42}, abstract = {Dieses Projekt befasst sich mit Fragestellungen zur Anwendung von k{\"u}nstlicher Intelligenz im Bereich der Technischen Sauberkeit. Durch Literaturforschungen, die einen Ablauf nach Fettke 2006 haben, werden KI-Anwendungen gesucht, die bereits im Zusammenhang mit der Technischen Sauberkeit verwendet werden. Die Forschungen konnten zw{\"o}lf Literaturquellen ermitteln. Durch diese Literaturanalyse wurde festgestellt, dass 91 Prozent CV (Computer Vision) zur Partikelerkennung verwenden. Aus diesem Grund wurde anschließend ein CV Modell zur Partikelerkennung implementiert. Durch die Konfusionsmatrix konnte eine Treffergenauigkeit von 82 Prozent festgestellt werden. Daraus folgt, dass eine Partikelklassifikation m{\"o}glich ist. Abschließend wurde eine weitere Literaturforschung zu Text Mining Applikationen durchgef{\"u}hrt, da der Bereich der Qualit{\"a}tsanalyse im Monitoring laut Aufgabenstellung eingezogen werden sollte. In dieser konnte kein positives Ergebnis erzielt werden, da speziell nach fertigen Anwendungen gesucht wurde, die Analysetexte im Bereich der technischen Sauberkeit kategorisieren k{\"o}nnen.}, language = {de} } @article{MuellerRueckJobstetal., author = {M{\"u}ller, Max and R{\"u}ck, Thomas and Jobst, Simon and Pangerl, Jonas and Weigl, Stefan and Bierl, Rudolf and Matysik, Frank-Michael}, title = {An Algorithmic Approach to Compute the Effect of Non-Radiative Relaxation Processes in Photoacoustic Spectroscopy}, series = {Photoacoustics}, volume = {26}, journal = {Photoacoustics}, publisher = {Elsevier}, doi = {10.1016/j.pacs.2022.100371}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-39935}, abstract = {Successful transfer of photoacoustic gas sensors from laboratory to real-life applications requires knowledge about potential cross-sensitivities towards environmental and gas matrix changes. Multi-dimensional calibration in case of cross-sensitivities can become very complex or even unfeasible. To address this challenge, we present a novel algorithm to compute the collision based non-radiative efficiency and phase lag of energy relaxation on a molecular level (CoNRad) for photoacoustic signal calculation. This algorithmic approach allows to calculate the entire elaxation cascade of arbitrarily complex systems, yielding a theoretical photoacoustic signal. In this work the influence of varying bulk compositions, i.e. nitrogen (N2), oxygen (O2) and water (H2O) on the photoacoustic signal during methane (CH4) detection is demonstrated. The applicability of the algorithm to other photoacoustic setups is shown exemplary by applying it to the relaxational system investigated in [1]. Hayden et al. examined the effect of water on photoacoustic carbon monoxide (CO) detection.}, language = {en} } @inproceedings{MelekhovAbbLechneretal., author = {Melekhov, Evgeny and Abb, Valerius and Lechner, Alfred and Kammler, Martin}, title = {Development of a glass-fiber-based spectrometer for the determination of drug residues in groundwater}, series = {Tagungsband 2. Symposium Elektronik und Systemintegration ESI 2020 "Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung"}, booktitle = {Tagungsband 2. Symposium Elektronik und Systemintegration ESI 2020 "Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung"}, editor = {Ivanov, Artem and Bicker, Marc and Patzelt, Peter}, isbn = {978-3-9818439-4-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-2174}, pages = {101 -- 109}, abstract = {Within the scope of this project, a portable measuring device has been developed which enables a cost-effective analysis of organic substances from ppm to sub-ppm range, such as drug residues in groundwater. The measurement is carried out by means of a surface-enhanced Raman scattering effect (SERS effect) and an exchangeable sensor head. The sensor head used is a nanostructured optical glass fiber glued into a fiber cannula. The tip of the fiber has been processed to act as a SERS cell. The fiber cannula is connected to a freely movable patch cable by using an adapter. Para-thiocresol is used to characterize the SERS cells.}, language = {en} } @techreport{AndratschkeCeulloDawoudetal., author = {Andratschke, Christin and Ceullo, Laura and Dawoud, Belal and Draeger, Susan and Gerdes, Thorsten and Giebisch, Matthias and Grießhammer, Peter and Haas, Katharina and Haug, Sonja and Helling, Dominik and Kominis, Lena and Lang, Christian and Malz, Sebastian and Melzl, Johannes and Michlbauer, David and M{\"u}hlberger, Thomas and Nagl, Klaus and Preis, Michael and Rechenauer, Christian and Riederer, Michael and R{\"u}ckerl, Alexander and Saller, Tobias and Schnabl, Andreas and Stadler, Michael and Steffens, Oliver and Steininger, Peter and Stelzl, Andr{\´e} and Toutouly, Lovis and Trauner, Matthias and Vetter, Miriam and Walbrunn, Johannes and Weber, Karsten and Zielbauer, Lukas}, title = {MAGGIE: Energetische Modernisierung des genossenschaftlichen Wohnquartiers Margaretenau in Regensburg}, editor = {Steffens, Oliver}, address = {Regensburg}, isbn = {978-3-96256-100-0}, doi = {10.35096/othr/pub-5335}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-53354}, pages = {XVIII, 462 S.}, abstract = {Im Projekt MAGGIE wurden f{\"u}r das genossenschaftliche historische Stadtquartier „Margaretenau" in Regensburg Musterl{\"o}sungen f{\"u}r energieoptimiertes Wohnen mit innovativen Wandaufbauten aus solaraktiven Baukonstruktionen und einer vorhersagebasierten Versorgungstechnologie erforscht. Dazu wurde ein bestehendes Wohngeb{\"a}ude als Demonstrations- und Versuchsobjekt mit einem neuartigen, besonders effizienten Hybridsystem aus W{\"a}rmepumpentechnologie und Kraft- W{\"a}rme-Kopplung ausgestattet und untersucht, erg{\"a}nzt durch eine dynamische W{\"a}rmelogistik zur Verringerung von Verteilungsverlusten. Das System wurde durch ein neu entwickeltes, allgemein einsetzbares Planungs-, Optimierungs- und Steuerungstool ausgelegt und im Betrieb geregelt. Die in Echtzeit laufende Nachoptimierung des Systems w{\"a}hrend des Betriebs greift dabei auf reale Monitoringdaten zu. Die Einbindung von Nutzerbedarfsprofilen, Stromb{\"o}rse und Wetterdaten in die Steuerung gestattet einen dynamischen und perspektivischen Anlagenbetrieb zur Maximierung der Solar- und Umweltw{\"a}rme-Anteile der Energieversorgung und leistet damit einen wirksamen Beitrag zu einem emissionsarmen, klimafreundlichen Geb{\"a}udebetrieb. F{\"u}r die denkmalgerechte Modernisierung der historischen Fassaden wurde ein solaraktives und solaradaptives Außenputzsystem entwickelt und in der Realit{\"a}t getestet. Am Bestandsgeb{\"a}ude kam anstelle eines W{\"a}rmed{\"a}mmverbundsystems ein innovativer D{\"a}mmputz mit Mikrohohlglaskugeln zum Einsatz. Die Skalierbarkeit erlaubt eine abschnittsweise Modernisierung des gesamten Ensembles {\"u}ber mehrere Jahre. Durch die hohe Energieeffizienz wird die Warmmiete f{\"u}r die Bewohner der genossenschaftlichen Siedlung durch die Modernisierungsmaßnahmen nicht erh{\"o}ht, so dass auch nach der Modernisierung ein bezahlbares Wohnen sichergestellt wird.}, subject = {Altbaumodernisierung}, language = {de} } @inproceedings{SchererVitzthumeckerBierl, author = {Scherer, Leo and Vitzthumecker, Thomas and Bierl, Rudolf}, title = {Capacitive PCB sensor for the detection of insects in intelligent traps}, series = {Applied Research Conference 2022 Conference Proceedings: 4th July 2022, University of Applied Sciences Ansbach (Onsite Conference)}, booktitle = {Applied Research Conference 2022 Conference Proceedings: 4th July 2022, University of Applied Sciences Ansbach (Onsite Conference)}, editor = {Uhl, Christian and Walter, Michael and Stiehl, Annika}, publisher = {Hochschule Ansbach}, address = {Ansbach}, doi = {10.25929/qbwt-zf40}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-55837}, pages = {519 -- 523}, abstract = {Reliable and fast detection of pest in the food processing and pharmaceutical industry is crucial to ensure hygienically safe, pure and healthy products. This is why intelligent traps, that are able to detect insects automatically are needed. For this, a capacitive PCB sensor is developed and tested, which could be a simplistic, low power solution to the problem. This includes design, footprint generation and simulation as well as testing different types of capacitve sensing against noise immunity and sensitivity to Blattella germanica, the German cockroach. It is shown that a single specimen can very well and reliably be detected by the developed sensor.}, language = {en} } @article{SerbunBornmannNavitskietal., author = {Serbun, Pavel and Bornmann, Benjamin and Navitski, Aliaksandr and M{\"u}ller, G{\"u}nter and Prommesberger, Christian and Langer, Christoph and Dams, Florian and Schreiner, Rupert}, title = {Stable field emission of single B-doped Si tips and linear current scaling of uniform tip arrays for integrated vacuum microelectronic devices}, series = {Journal of Vacuum Science \& Technology B Nanotechnology and Microelectronics}, volume = {31}, journal = {Journal of Vacuum Science \& Technology B Nanotechnology and Microelectronics}, number = {2}, publisher = {AIP Publishing}, doi = {10.1116/1.4765088}, abstract = {Advanced Si-based semiconductor technology is most suitable to fabricate uniform nanostructures as integrated field emitter arrays for novel vacuum electronic devices. In order to improve the field emission homogeneity and stability of p-type silicon tip arrays for pulsed sensor applications, the authors have systematically studied the influence of the fabrication parameters on the tip shape and on the specific operating conditions. Based on detailed design calculations of the field enhancement, they have fabricated two series of hexagonal arrays of B-doped Si-tips in a triangular arrangement. The first (second) type contains three (four) patches with different number of tips (1, 91, 547 and 1, 19, 1027, 4447 for the first and second type, respectively) of about 1 (2.5) μm height, ∼20 (20) nm apex radius, and 20 (10) μm pitch. The field emission properties of both individual tips and complete arrays were investigated with a field emission scanning microscope at a pressure of 10-9 mbar. The current plateau of these tips typically occurs at about 10 (3) nA and around 65 (25) V/μm field level. In this carrier saturation range, single tips provide the highest current stability (<5\%) and optical current switching ratio (∼2.5). Fairly homogeneous emission of the tip arrays leads to an undershooting of the expected linear scaling of the mean plateau current as well as to a much improved current stability (<1\%).}, language = {en} } @article{MalzKrenkelSteffens, author = {Malz, Sebastian and Krenkel, Walter and Steffens, Oliver}, title = {Infrared Reflective Wall Paint in Buildings: Energy Saving Potentials and Thermal Comfort}, series = {Energy and Buildings}, volume = {224}, journal = {Energy and Buildings}, number = {October}, publisher = {Elsevier}, issn = {0378-7788}, doi = {10.1016/j.enbuild.2020.110212}, abstract = {The reduction of the energy demand of existing buildings is the main objective of building refurbishment. Managing the heat radiation properties of the wall construction is a possible way to develop highly effective and resource efficient insulation materials and concepts. The application of infrared reflective wall paints and coatings has been studied since the latter half of the 20th century. A brief review of the literature gives an account of the current research status. One has to realise that the conclusions are not uniformly consistent but depend strongly on the specific boundary conditions and investigated parameters. The study presented here discusses the usage of infrared reflective wall paint in conjunction with heat insulation for historic brick masonry. The possible energy savings are linked to the resulting thermal comfort. We identify critical parameters that must be taken into account when using infrared reflective wall paint and derive recommended design rules for the refurbishment of such building types. The findings prove that infrared reflective wall paint can decrease heat losses by 18\% and up to 22\% if comfort conditions are considered. Increasing energy savings can also cause the negative effect of high radiative asymmetry. Thus, each configuration must be observed in detail.}, language = {en} } @misc{MelekhovAbbWeidaueretal., author = {Melekhov, Evgeny and Abb, Valerius and Weidauer, Tobias and Kammler, Martin and Lechner, Alfred}, title = {Tunable Nanopillars as Surface Enhanced Raman Scattering (SERS) Active Structure for Optical Quartz Glass Fiber}, series = {SMSI 2021 - Sensors and Instrumentation}, journal = {SMSI 2021 - Sensors and Instrumentation}, publisher = {AMA Association for Sensors and Measurement}, isbn = {978-3-9819376-4-0}, doi = {10.5162/SMSI2021/B8.2}, pages = {153 -- 154}, abstract = {In this work, a simple cost effective method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas on a tip of an optical quartz glass fiber is described. The structures are prepared using lithography-less dry etching. Gold nanoparticles are used as an etching mask using a thin metal-film thermal dewetting technique. The structures are applied as sensor for label-free analysis of organic substances in ppb range, such as drug residues in groundwater. The measurements are carried out by means of a Surface-enhanced Raman scattering (SERS) effect, an exchangeable sensor head, and a portable Raman device. This method allows in situ applications. Parathiocresol is used as a model substance to characterize the SERS cells. For metallization, gold and silver are compared. Reproducible SERS enhancement factors up to 10 7 are evaluated.}, language = {en} } @misc{Steffens, author = {Steffens, Oliver}, title = {Solares Bauen in der Margaretenau}, series = {Symposium Klimaneutrale Stadt, OTH Regensburg / Stadt Regensburg und Baugenossenschaft Margaretenau e.G., 09.02.2019, Regensburg}, journal = {Symposium Klimaneutrale Stadt, OTH Regensburg / Stadt Regensburg und Baugenossenschaft Margaretenau e.G., 09.02.2019, Regensburg}, language = {de} } @misc{vanderWeerdBierlMatysik, author = {van der Weerd, Bastiaan and Bierl, Rudolf and Matysik, Frank-Michael}, title = {A Conductivity Probe for Determination of the Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO)}, series = {Proceedings of the 9th ISC Modern Analytical Chemistry 2013, Prag}, journal = {Proceedings of the 9th ISC Modern Analytical Chemistry 2013, Prag}, language = {en} } @misc{RueckHofmannBierl, author = {R{\"u}ck, Thomas and Hofmann, Matthias and Bierl, Rudolf}, title = {Development of a miniaturized photoacoustic multigas sensing system for trace gas measurement}, series = {17th International Conference on Photoacoustic and Photothermal Phenomena, Oct. 20-24, 2013, Suzhou China}, journal = {17th International Conference on Photoacoustic and Photothermal Phenomena, Oct. 20-24, 2013, Suzhou China}, language = {en} } @misc{RueckMatysikBierl, author = {R{\"u}ck, Thomas and Matysik, Frank-Michael and Bierl, Rudolf}, title = {Development of a miniaturized photoacoustic multigas sensing system for trace gas measurement}, series = {analytica conference 2014, 1. bis 4. April, M{\"u}nchen}, journal = {analytica conference 2014, 1. bis 4. April, M{\"u}nchen}, language = {en} } @misc{RueckMatysikBierl, author = {R{\"u}ck, Thomas and Matysik, Frank-Michael and Bierl, Rudolf}, title = {Comparison of acoustic detectors for use in miniaturized photoacoustic devices designed for nitrogen dioxide trace gas measurement}, series = {ANAKON, 23.-26.3.2015, Graz}, journal = {ANAKON, 23.-26.3.2015, Graz}, language = {en} } @techreport{AndratschkeCeulloDawoudetal., author = {Andratschke, Christin and Ceullo, Laura and Dawoud, Belal and Draeger, Susan and Gerdes, Thorsten and Giebisch, Matthias and Grießhammer, Peter and Haas, Katharina and Haug, Sonja and Helling, Dominik and Kominis, Lena and Lang, Christian and Malz, Sebastian and Melzl, Johannes and Michlbauer, David and M{\"u}hlberger, Thomas and Nagl, Klaus and Preis, Michael and Rechenauer, Christian and Riederer, Michael and R{\"u}ckerl, Alexander and Saller, Tobias and Schnabl, Andreas and Stadler, Michael and Steffens, Oliver and Steininger, Peter and Stelzl, Andr{\´e} and Toutouly, Lovis and Trauner, Matthias and Vetter, Miriam and Walbrunn, Johannes and Weber, Karsten and Zielbauer, Lukas}, title = {MAGGIE: Energetische Modernisierung des genossenschaftlichen Wohnquartiers Margaretenau in Regensburg}, editor = {Steffens, Oliver}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-96256-100-0}, doi = {10.35096/othr/pub-5901}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-59011}, pages = {XVIII, 462 S.}, abstract = {Im Projekt MAGGIE wurden f{\"u}r das genossenschaftliche historische Stadtquartier „Margaretenau" in Regensburg Musterl{\"o}sungen f{\"u}r energieoptimiertes Wohnen mit innovativen Wandaufbauten aus solaraktiven Baukonstruktionen und einer vorhersagebasierten Versorgungstechnologie erforscht. Dazu wurde ein bestehendes Wohngeb{\"a}ude als Demonstrations- und Versuchsobjekt mit einem neuartigen, besonders effizienten Hybridsystem aus W{\"a}rmepumpentechnologie und Kraft- W{\"a}rme-Kopplung ausgestattet und untersucht, erg{\"a}nzt durch eine dynamische W{\"a}rmelogistik zur Verringerung von Verteilungsverlusten. Das System wurde durch ein neu entwickeltes, allgemein einsetzbares Planungs-, Optimierungs- und Steuerungstool ausgelegt und im Betrieb geregelt. Die in Echtzeit laufende Nachoptimierung des Systems w{\"a}hrend des Betriebs greift dabei auf reale Monitoringdaten zu. Die Einbindung von Nutzerbedarfsprofilen, Stromb{\"o}rse und Wetterdaten in die Steuerung gestattet einen dynamischen und perspektivischen Anlagenbetrieb zur Maximierung der Solar- und Umweltw{\"a}rme-Anteile der Energieversorgung und leistet damit einen wirksamen Beitrag zu einem emissionsarmen, klimafreundlichen Geb{\"a}udebetrieb. F{\"u}r die denkmalgerechte Modernisierung der historischen Fassaden wurde ein solaraktives und solaradaptives Außenputzsystem entwickelt und in der Realit{\"a}t getestet. Am Bestandsgeb{\"a}ude kam anstelle eines W{\"a}rmed{\"a}mmverbundsystems ein innovativer D{\"a}mmputz mit Mikrohohlglaskugeln zum Einsatz. Die Skalierbarkeit erlaubt eine abschnittsweise Modernisierung des gesamten Ensembles {\"u}ber mehrere Jahre. Durch die hohe Energieeffizienz wird die Warmmiete f{\"u}r die Bewohner der genossenschaftlichen Siedlung durch die Modernisierungsmaßnahmen nicht erh{\"o}ht, so dass auch nach der Modernisierung ein bezahlbares Wohnen sichergestellt wird.}, subject = {Altbaumodernisierung}, language = {de} } @book{Steffens, author = {Steffens, Oliver}, title = {On Media, typewriters, logic and truth: Essays}, address = {Regensburg}, doi = {10.35096/othr/pub-5838}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58380}, publisher = {Ostbayerische Technische Hochschule Regensburg}, pages = {77}, abstract = {Essays on the Media Revolution in the 19th Century, when sound recording, film and typewriter changed the way of communication, literature, and arts; on the societal impact and role models that came along with the invention and success of the typewriting machine; on early mathematical and mechanistic ways of reasoning the medieval philosopher Ram{\´o}n Llull, Leibniz's idea of binary numbers and the advent of artificial intelligence.}, language = {en} } @unpublished{Steffens, author = {Steffens, Oliver}, title = {The Media Revolution in the 19th Century: How Sound Recording, Motion Pictures and Writing Machines affected human perception, thinking, and our society until today}, address = {Regensburg}, doi = {10.13140/RG.2.2.29059.53283}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58376}, pages = {17}, abstract = {Which influence had the sudden appearance of sound recording, film, and typewriters at the end of the 19th century on the human perception of and our thinking about what we consider "reality"? How did our society change with these technological innovations? After millennia of speech and the culture of writing, a fundamental disruption occurred when Thomas Alva Edison introduced his "phonograph" in 1877. In his book "Grammophon, Film, Typewriter" (Brinkmann \& Bose, Berlin 1986), Friedrich Kittler (1943-2011) discusses this question from his perspective as literary scholar and media theorist, reviewing contemporary authors to let them bear witness to their experiences and impressions of the then-new media. This essay intends to be a short extract of Kittler's book, meandering between additional sources of historians, writers, commentators, yet always coming back to Kittler's fascinating panopticon.}, language = {en} } @unpublished{Steffens, author = {Steffens, Oliver}, title = {Leibniz, Llull and the Logic of Truth: Precursors of Artificial Intelligence}, address = {Regensburg}, doi = {10.13140/RG.2.2.28425.06243}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58399}, pages = {10}, abstract = {Mankind has always been confronted with limited knowledge about Nature and many people devoted their lives and intellects to the very question: How to gain knowledge, confirm ideas and theories, and understand the world we live in? Religion was one fundamental base for explanations and existential questions. Philosophy and Science were the other. Nowadays, science and technology dominate our daily lives, religion and metaphysics have lost their former dominance, while our thoughts and factual knowledge are increasingly governed by the digitised versions of conversation and discussion, filtered and guided by the algorithms of social networks. Today, "artificial intelligence" is a phenomenon in information technology which takes over everyday routines. A new ideal, a new promise, and at the same time used as a stratagem by political and economic systems to guide and manipulate our thinking, values, and behaviour. But nothing is so new that one could not find its precursors in earlier times. Science and mathematics has kindled many brilliant ideas. Can we describe the world by numbers, find truth and explanation in mathematical structures? This essay is devoted to early ideas by the medieval philosopher Ram{\´o}n Llull, the great rationalist G.W. Leibniz, and early approaches to combinations, number theory. and information processing. Llull's thinking machine and subsequent endeavours to find methods of mechanical reasoning and inference paved the way to modern-day concepts of artificial intelligence.}, language = {en} } @techreport{Steffens, author = {Steffens, Oliver}, title = {Report on a Vernier (Nonius Rule) for Non-Linear Scales}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58926}, pages = {7}, abstract = {The vernier or nonius (in other languages) goes back to a measuring tool used in navigation and astronomy named after its inventor Pedro Nunes (1502-1578; Latin: Petrus Nonius), a Portuguese mathematician and navigator. The nonius was created in 1542 to take finer measurements on circular instruments such as the astrolabe. In 1631 the French mathematician Pierre Vernier (1580-1637) adapted and simplified the system which was later denoted "vernier". We present a method to construct a vernier-like scale for logarithmic scales (as used for typical slide rules), which results in variable tick spacings. The idea is to put the non-linear scale on a spiral. The method can be applied to any non-linear scale, not only logarithmic scales.}, language = {en} } @techreport{Steffens, type = {Working Paper}, author = {Steffens, Oliver}, title = {A Perpetual Calendar Slide Rule}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58935}, abstract = {We present a method and demonstrate the construction of an analog (mechanical/graphical) perpetual calendar device for the Gregorian calendar system. It allows to calculate the weekdays of a day in any year (and vice versa).}, language = {en} } @book{Steffens, author = {Steffens, Oliver}, title = {K{\"u}nstliche Atome im Magnetfeld}, publisher = {Mainz}, address = {Aachen}, isbn = {3-89653-526-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20740}, publisher = {Ostbayerische Technische Hochschule Regensburg}, abstract = {Halbleiter-Quantenpunkte sind interessante Objekte, um die Elektron-Elektron-Wechselwirkung eines endlichen Systems im Magnetfeld zu studieren. Aufgrund der Analogie zu nat{\"u}rlichen Atomen werden Quantenpunkte h{\"a}ufig als 'k{\"u}nstliche Atome' bezeichnet. Die {\"A}hnlichkeit zu nat{\"u}rlichen Atomen resultiert aus der Schalenstruktur eines harmonischen Einschlußpotentials, wodurch 'magische' Elektronenzahlen (analog zu Edelgasen) mit vollst{\"a}ndig besetzten (geschlossenen) Schalen und folglich geringer Elektronenaffinit{\"a}t ausgezeichnet werden. Die St{\"a}rke des Einschlußpotentials entspricht einer effektiven 'Kernladung', die mit einer bestimmten Elektronenzahl im System verkn{\"u}pft ist. Infolge der geringen Bindungsenergie (einige meV) sowie weiterer Materialparameter kann man in Quantenpunkten magnetfeldabh{\"a}ngige Effekte untersuchen, die mit Niveaukreuzungen im Energiespektrum verbunden sind. Derartige Effekte treten bereits bei experimentell realisierbaren Magnetfeldern von einigen Tesla auf, im Gegensatz zu nat{\"u}rlichen Atomen. Im ersten Teil meiner Arbeit werden die Grundzustandseigenschaften von 2D-Halbleiter-Quantenpunkten auf GaAs-Basis mit wenigen Elektronen (N < 20) untersucht. Die Behandlung der Coulomb-Wechselwirkung mit dem Konzept der Strom-Spin-Dichtefunktional-Theorie von Vignale und Rasolt (1988) erlaubt die Ber{\"u}cksichtigung des Spinfreiheitsgrades sowie magnetfeldabh{\"a}ngiger Korrelationen. In die dazu ben{\"o}tigte Austausch-Korrelations-Energie gehen geeignete lokale N{\"a}herungen ein (Lokale Spindichte- und Vortizit{\"a}ts-N{\"a}herung). Durch Abbildung des Vielteilchenproblems auf ein Kohn-Sham-System mit effektiven Einteilchen-Potentialen, die außer dem Hartree-Potential spinabh{\"a}ngige Austausch-Korrelations-Potentiale und ein Austausch-Korrelations-Vektorpotential umfassen, k{\"o}nnen neben der N-Teilchen-Grundzustandsenergie auch die Ladungs- und Spindichte sowie die Stromdichte berechnet werden.}, language = {de} } @inproceedings{LangSteinbornSteffensetal., author = {Lang, Christian and Steinborn, Florian and Steffens, Oliver and Lang, Elmar Wolfgang}, title = {Electricity Load Forecasting - An Evaluation of Simple 1D-CNN Network Structures}, series = {International Conference on Time Series and Forecasting (ITISE 2019), Proceedings of Papers Vol. 2, 25-27 September 2019, Granada (Spain)}, booktitle = {International Conference on Time Series and Forecasting (ITISE 2019), Proceedings of Papers Vol. 2, 25-27 September 2019, Granada (Spain)}, isbn = {978-84-17970-78-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-16649}, pages = {797 -- 806}, abstract = {This paper presents a convolutional neural network (CNN)which can be used for forecasting electricity load profiles 36 hours intothe future. In contrast to well established CNN architectures, the inputdata is one-dimensional. A parameter scanning of network parameters isconducted in order to gain information about the influence of the kernelsize, number of filters, and dense size. The results show that a goodforecast quality can already be achieved with basic CNN architectures.The method works not only for smooth sum loads of many hundredconsumers, but also for the load of apartment buildings}, language = {en} } @article{HaugSteffens, author = {Haug, Sonja and Steffens, Oliver}, title = {Die Akzeptanz von Baumaßnahmen im Planungsstadium}, series = {Deutsches Ingenieurblatt}, journal = {Deutsches Ingenieurblatt}, number = {3}, publisher = {Schiele \& Sch{\"o}n}, address = {Berlin}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-16499}, pages = {20 -- 27}, abstract = {Der kontinuierliche Sanierungs- und Modernisierungsprozess im Geb{\"a}udebestand in Deutschland, verst{\"a}rkt durch den Mangel an bezahlbarem Wohnraum, l{\"a}sst das gesellschaftliche Interesse an klimafreundlichen und ressourcenschonenden Technologien stetig wachsen. Modernisierungsmaßnahmen betreffen h{\"a}ufig Geb{\"a}ude (auch aus der j{\"u}ngeren Vergangenheit), deren historischer und architektonischer Wert oft {\"u}bersehen wird und der unter einer modernen W{\"a}rmed{\"a}mmverbundfassade zu verschwinden droht. Infolge einer intensiven bauhistorischen Besch{\"a}ftigung mit dem genossenschaftlichen Wohnungsbestand der Zwischenkriegszeit in der Stadt Regensburg hat sich ein interdisziplin{\"a}res Team aus Bauforschung, Architektur, Planung, Bauphysik und Geb{\"a}udetechnik zusammengefunden, um nachhaltige L{\"o}sungskonzepte f{\"u}r die energetische Modernisierung und Restaurierung historischer Quartiere zu erforschen. Dieser Beitrag widmet sich den Erkenntnissen einer sozialwissenschaftliche Studie, die als Erg{\"a}nzung und Hintergrundinformation zu den technischen und bauhistorischen Untersuchungen durchgef{\"u}hrt wurde.}, subject = {Altbaumodernisierung}, language = {de} } @inproceedings{MalzSteffensKrenkel, author = {Malz, Sebastian and Steffens, Oliver and Krenkel, Walter}, title = {Solaraktive Fassaden im Bestandsbau}, series = {Bauphysiktage 2019 in Weimar - Bauphysik in Forschung und Praxis, 25. und 26. September 2019, Bauhaus-Universit{\"a}t Weimar}, booktitle = {Bauphysiktage 2019 in Weimar - Bauphysik in Forschung und Praxis, 25. und 26. September 2019, Bauhaus-Universit{\"a}t Weimar}, editor = {V{\"o}lker, Conrad and Kornadt, Oliver and Jentsch, Mark and Vogel, Albert}, isbn = {978-3-00-063821-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20464}, pages = {127 -- 129}, abstract = {Im Rahmen des Forschungsprojektes MAGGIE, das am Beispiel des historischen Quartiers Margaretenau in Regensburg innovative L{\"o}sungen f{\"u}r modernes und bezahlbares Wohnen erforscht, soll {\"u}ber eine solaraktive Fassade Sonnenw{\"a}rme im Bestandsmauerwerk eingespeichert werden, um so den Energiebedarf des Geb{\"a}udes zu reduzieren.}, language = {de} } @book{SteffensBergmannHaugetal., author = {Steffens, Oliver and Bergmann, Anja and Haug, Sonja and Rechenauer, Christian and Saller, Tobias and Schaubeck, Simon and Schr{\"o}ter, Sonja and Vernim, Matthias and Wittmann, Matthias and Zeitler, Annika}, title = {RENARHIS - Nachhaltige energetische Modernisierung und Restaurierung historischer Stadtquartiere}, edition = {Stand Januar 2016}, address = {Bonn}, organization = {Bundesinstitut f{\"u}r Bau-, Stadt- und Raumforschung -BBSR, Bonn}, isbn = {9783879942817}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201707124087}, pages = {286}, abstract = {Die Lebensqualit{\"a}t in einem Stadtquartier l{\"a}sst sich steigern, wenn Baukunst, Energieeffizienz, regenerative Energieversorgung und kosteng{\"u}nstiges Wohnen zusammenkommen. All das braucht umfassendes Know-how von Architekten, Planern und Betreibern. Forscher der Ostbayerischen Technischen Hochschule Regensburg (OTH) zeigen, wie ein historisches Stadtquartier behutsam modernisiert werden kann und gleichzeitig die Mieten bezahlbar bleiben. Das Bundesinstitut f{\"u}r Bau-, Stadt- und Raumforschung (BBSR) hat die Forschungsarbeit kostenlos herausgegeben. Die Handlungsempfehlungen des Leitfadens richten sich an Planer, Architekten und Eigent{\"u}mer. Wie l{\"a}sst sich eine Geb{\"a}udesanierung erfolgreich zum Zwecke des Klimaschutzes und der nachhaltigen Wohnqualit{\"a}t umsetzen? Strategien hierf{\"u}r entwickelten Professor Oliver Steffens und sein Forschungsteam der OTH am Beispiel des Plato-Wild-Ensembles, einem genossenschaftlichen Wohnquartier aus den 1920er-Jahren im Regensburger Osten. Das Besondere an dem Sanierungskonzept ist sein fach{\"u}bergreifender Ansatz: 30 Projektbeteiligte aus den technischen sowie wirtschafts- und sozialwissenschaftlichen Disziplinen erarbeiteten f{\"u}r das Plato-Wild-Ensemble mehrere L{\"o}sungsans{\"a}tze: Das Projektteam verfolgte nach einer eingehenden Bestandsaufnahme das Konzept der Nachverdichtung sowie der energetischen Ert{\"u}chtigung der Geb{\"a}udeh{\"u}lle. Ziel war dabei, die historische Fassade zu bewahren. Das Projektteam unterlegte die Ans{\"a}tze der architektonischen Modernisierung sowie der regenerativen Energieversorgung mit zahlreichen Entw{\"u}rfen, Berechnungen und Simulationen. Bauphysikalische Betrachtungen zum W{\"a}rme-, Feuchte- und Schallschutz waren ein weiterer wichtiger Baustein.}, language = {de} } @masterthesis{OberhoferGruber, type = {Bachelor Thesis}, author = {Oberhofer, Marika and Gruber, Ramona}, title = {Feuchte in Tunnelinnenschalen. Eine Literaturstudie}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20635}, school = {Ostbayerische Technische Hochschule Regensburg}, language = {de} } @misc{Hoeflich, type = {Master Thesis}, author = {H{\"o}flich, Daniel}, title = {Thermische Berechnungen und hygrothermische Detail-Simulationen f{\"u}r eine Geb{\"a}udemodernisierung mit kapillaraktiver Innend{\"a}mmung}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20514}, school = {Ostbayerische Technische Hochschule Regensburg}, language = {de} } @article{StierstorferWellnitzSteffens, author = {Stierstorfer, Johannes and Wellnitz, Felix and Steffens, Oliver}, title = {Integrale Bauforschung und simulationsgest{\"u}tzte Analysen zur Wahrung historischer Bausubstanz am Beispiel der Asamkirche St. Georg zu Weltenburg}, series = {Bauphysik}, volume = {39}, journal = {Bauphysik}, number = {2}, issn = {0171-5445}, doi = {10.1002/bapi.201710016}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20540}, pages = {135 -- 143}, abstract = {Die Klosterkirche St. Georg zu Weltenburg an der Donau, sp{\"a}tbarockes Hauptwerk der Br{\"u}der Asam und bayerische Welterbest{\"a}tte, musste sich aufgrund ihrer topographisch, geologisch und klimatisch exponierten Lage in der Vergangenheit tiefgreifenden Instandsetzungsmaßnahmen unterziehen. Um der hygrischen Problematik im Inneren des Kirchenraumes zu begegnen, wurde ein außergew{\"o}hnlicher Sanierungsansatz verfolgt, dessen bauphysikalische und raumklimatische Verifizierung im Rahmen dieses Forschungsprojektes durchgef{\"u}hrt wird. Dabei steht die Optimierung des Raumklimas im Zentrum der Untersuchungen. Ganzheitlich betrachtet stellt sich die Frage: Welche Maßnahmen d{\"u}rfen - bei Bewahrung der denkmalgesch{\"u}tzten Bausubstanz - ergriffen werden, um eine nachhaltige Nutzung historischer Bauwerke zu erm{\"o}glichen und dabei die Anforderungen der heutigen Zeit zu erf{\"u}llen?}, language = {de} } @techreport{BergmannHaugRechenaueretal., author = {Bergmann, Anja and Haug, Sonja and Rechenauer, Christian and Saller, Tobias and Schaubeck, Simon and Scheuerer (Scheuerer-Lenzen), Birgit and Schr{\"o}ter, Sonja and Schulz-Brize, Thekla and Steffens, Oliver and Vernim, Matthias and Matthias, Wittmann and Zeitler, Annika and Zimmermann, Patrick}, title = {Nachhaltige energetische Modernisierung und Restaurierung historisch wertvoller Stadtquartiere. Forschungsprojekt RENARHIS - Endbericht und Leitfaden. Zukunft Bau Projekt Nr. II 3-F20-11-1-038 (BBSR)}, editor = {Steffens, Oliver}, address = {Regensburg}, organization = {Ostbayerische Technische Hochschule Regensburg}, doi = {10.13140/RG.2.1.2465.7364}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-20766}, pages = {338}, abstract = {Dieser Bericht in Gestalt eines Leitfadens f{\"u}r eine nachhaltige energetische Modernisierung von historischen Stadtquartieren mit besonderem architektonischen Wert ist das Ergebnis eines Forschungsprojekts an der Ostbayerischen Technischen Hochschule Regensburg, das vom Bundesinstitut f{\"u}r Bau-, Stadt- und Raumforschung im Rahmen der F{\"o}rderinitiative „Zukunft Bau" (Projekt Nr. II 3-F20-11-1-038 / SWD-10.08.18.7-12.21) in den Jahren 2012 bis 2014 gef{\"o}rdert wurde. Im Projekt RENARHIS („Regenerative Energieversorgung als Schwerpunkt einer nachhaltigen Modernisierung historischer Stadtquartiere") wurden am Modell eines genossenschaftlichen Wohnquartiers aus den 1920er Jahren Restaurierungs- und Modernisierungsstrategien erarbeitet. Das „Plato-Wild-Ensemble" liegt im Regensburger Stadtosten, außerhalb der mittelalterlichen Altstadt. Es steht nicht unter Denkmalschutz, kann aber gleichwohl aus architektonischen und sozialgeschichtlichen Gr{\"u}nden als Beispiel f{\"u}r musterg{\"u}ltigen und sch{\"a}tzenswerten genossenschaftlichen Wohnungsbau gelten. In diesem Leitfaden sollen aus den Erfahrungen und L{\"o}sungsans{\"a}tzen des Projekts allgemeine Handlungsgrund Orientierungshilfen geboten werden, die den Horizont des eigentlichen Projekts erweitern auf eine Vielzahl {\"a}hnlicher Bestandssituationen.}, language = {de} } @incollection{FalterGoldbergGuentheretal., author = {Falter, Thomas and Goldberg, Boris and G{\"u}nther, Swen and Steffens, Oliver}, title = {Transfererfolg messbar machen}, series = {Erfolgreicher Transfer in der Arbeitsgestaltung}, booktitle = {Erfolgreicher Transfer in der Arbeitsgestaltung}, editor = {Borowski, Esther and Cernavin, Oleg and Hees, Frank and Joerißen, Theresa}, publisher = {Waxmann}, address = {M{\"u}nster}, doi = {10.31244/9783830998082}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-67568}, publisher = {Ostbayerische Technische Hochschule Regensburg}, pages = {173 -- 187}, abstract = {Hochschulen f{\"u}r angewandte Wissenschaften (HAW) kommt als regionalen Innovationstreibern eine gesellschaftliche Verantwortung durch ihre Zusammenarbeit mit Unternehmen und Gesellschaft zu. Diese Zusammenarbeit geschieht im Rahmen von Aktivit{\"a}ten des Wissens- und Technologietransfers. Die Beurteilung des Erfolgs dieser Transferaktivit{\"a}ten verursacht jedoch regelm{\"a}ßig Schwierigkeiten, da geeignete Indikatoren zur Erfolgsmessung fehlen. Im Rahmen des vom Bundesministerium f{\"u}r Bildung und Forschung (BMBF) gef{\"o}rderten Verbundforschungsprojektes Transfer_i wurde ein Modell zur Objektivierung und Messung von Forschungsleistung, forschungsbasiertem Transfer sowie dessen Umsetzung am Markt in Form von Innovationen erarbeitet. Mit dem Forschungsprojekt wurden kausale Zusammenh{\"a}nge f{\"u}r das Gelingen von Transfer identifiziert und daraufhin entsprechende Indikatoren definiert, um auf dieser Basis die Steuerung von Transferprozessen zu erm{\"o}glichen. In diesem Beitrag werden zwei im Projekt Transfer_i entwickelte Modelle und Indikatoren vorgestellt, die die Voraussetzungen f{\"u}r einen erfolgreichen Transferprozess abbilden k{\"o}nnen. Auf dieser Grundlage zeigen wir anhand eines Projekts (MAGGIE) der Ostbayerischen Technischen Hochschule (OTH) Regensburg mit mehreren regionalen Partnern, wie die vorher definierten Modelle und Indikatoren in einem konkreten Anwendungsfall verwendet werden k{\"o}nnen. Abschließend beschreiben wir die erforderlichen Rahmenbedingungen f{\"u}r die erfolgreiche Umsetzung von Transfer an Hochschulen und wie darauf bezogene Indikatoren effektiv eingef{\"u}hrt werden k{\"o}nnen.}, subject = {Angewandte Forschung}, language = {de} } @article{PangerlSukulRuecketal., author = {Pangerl, Jonas and Sukul, Pritam and R{\"u}ck, Thomas and Fuchs, Patricia and Weigl, Stefan and Miekisch, Wolfram and Bierl, Rudolf and Matysik, Frank-Michael}, title = {An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone}, series = {Photoacoustics}, volume = {38}, journal = {Photoacoustics}, publisher = {Elsevier}, issn = {2213-5979}, doi = {10.1016/j.pacs.2024.100604}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-71279}, pages = {12}, abstract = {n this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) - providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 8.3 ppbV and an NNEA of 1.4E-9 Wcm 1Hz 0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field.}, language = {en} } @article{HauslerHolznerEhrnspergeretal., author = {Hausler, Peter and Holzner, Lukas and Ehrnsperger, Matthias and Bierl, Rudolf}, title = {Evaluation of the creep strength of samples produced by fused deposition modeling}, series = {Open Engineering}, volume = {14}, journal = {Open Engineering}, number = {1}, publisher = {de Gruyter}, doi = {10.1515/eng-2024-0084}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-79760}, pages = {10}, abstract = {Data sheets for 3D printing materials typically include softening temperature, impact strength, tensile strength, and stiffness. However, creep strength, an important parameter for components used over an extended period, is usually not included. Nevertheless, this parameter is of significant importance for components that are used over an extended period of time.This study compares the long-term creep behavior of a selection of materials that are commonly used in fused deposition modeling 3D printing. The materials under investigation are acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polylactic acid, and polycarbonate. In addition, the influence of fiber reinforcements on these materials is also examined. A simple, reproducible test procedure is proposed for users to determine and compare creep resistance of materials. This enables developers to select materials suitable for their own requirements on creep resistance and allows 3D-printing users to compare different materials. Results suggest that fiber reinforcement generally improves creep stability in 3D-printing materials, with GreenTEC Pro Carbon and add:north PC Blend HT LCF showing the most promise in this study.}, language = {en} } @article{SchelsEdlerHerdletal., author = {Schels, Andreas and Edler, Simon and Herdl, Florian and Hansch, Walter and Bachmann, Michael and Ritter, Daniela and Dudeck, Markus and Duesberg, Felix and Meyer, Manuel and Pahlke, Andreas and Hausladen, Matthias and Buchner, Philipp and Schreiner, Rupert}, title = {In situ quantitative field emission imaging using a low-cost CMOS imaging sensor}, series = {Journal of Vacuum Science \& Technology B}, volume = {40}, journal = {Journal of Vacuum Science \& Technology B}, number = {1}, publisher = {AIP Publishing}, doi = {10.1116/6.0001551}, abstract = {Spatially resolved field emission measurements represent an important factor in further development of existing field emitter concepts. In this work, we present a novel approach that allows quantitative analysis of individual emission spots from integral current-voltage measurements using a low-cost and commercially available CMOS camera. By combining different exposure times to extrapolate oversaturated and underexposed pixels, a near congruence of integral current and image brightness is shown. The extrapolation also allows parallel investigation of all individual tips participating in the total current with currents ranging from a few nanoampere to one microampere per tip. The sensitivity, which is determined by the integral brightness-to-current ratio, remains unchanged within the measurement accuracy even after ten full measurement cycles. Using a point detection algorithm, the proportional current load of each individual tip of the field emitter array is analyzed and compared at different times during the initial measurement cycle. Together with the extracted I-V curves of single emission spots from the integral measurement, the results indicate the effect of premature burnout of particularly sharp tips during conditioning of the emitter.}, language = {en} } @article{EdlerSchelsHerdletal., author = {Edler, Simon and Schels, Andreas and Herdl, Florian and Hansch, Walter and Bachmann, Michael and Dudeck, Markus and Duesberg, Felix and Pahlke, Andreas and Hausladen, Matthias and Buchner Philipp, and Schreiner, Rupert}, title = {Origin of the current saturation level of p-doped silicon field emitters}, series = {Journal of Vacuum Science \& Technology B}, volume = {40}, journal = {Journal of Vacuum Science \& Technology B}, number = {1}, publisher = {AIP Publishing}, doi = {10.1116/6.0001554}, abstract = {Using p-type semiconductors for field emitters is one simple way to realize an integrated current limiter to improve the lifetime of the cathode. In this work, the origin of the current saturation of p-type silicon emitters is investigated in detail. Single emitters are electrically characterized and compared to simulation results. With a simulation model considering a high surface generation rate and elevated tip temperature, a good agreement to the measured data is found. This observation is supported further by alteration of the surface experimentally. Electrical measurements after different treatments in hydrofluoric acid as well as heated and subsequent operation at room temperature are well explained by the influence of surface generation. Furthermore, it is shown that the field penetration leads to a small voltage drop and a strong geometry-dependent reduction of the field enhancement factor.}, language = {en} } @article{MilewskiHaug, author = {Milewski, Nadja and Haug, Sonja}, title = {At risk of reproductive disadvantage? Exploring fertility awareness among migrant women in Germany}, series = {Reproductive Biomedicine \& Society Online}, volume = {14}, journal = {Reproductive Biomedicine \& Society Online}, publisher = {Elsevier}, doi = {10.1016/j.rbms.2021.11.007}, pages = {226 -- 238}, abstract = {This study examined awareness about fertility among immigrant women and non-migrants in Germany. The social relevance of infertility and fertility treatment is increasing in Western countries due to continually low overall birth rates, a high rate of childlessness, and a gap between the desired and actual numbers of children. While there is growing interest in infertility and reproductive medicine in general, previous studies have rarely included immigrant or ethnic minorities in Europe. This study investigated whether knowledge on the age-related fertility decline (ARFD) varies between migrant groups and the majority group, and the role of education. Working hypotheses were drawn from theoretical considerations on frameworks of migrant assimilation. The analysis was based on data collected in a social science pilot study on reproductive medicine, representative of the general population ('NeWiRe' 2014-2015). The sample included 962 women aged 18-50 years living in Germany. Approximately 81\% of the sample were immigrants who originated from Turkey, Poland, the Balkan countries or countries of the (post-Soviet) Commonwealth of Independent States. While rather poor overall, knowledge on ARFD was found to be significantly lower in the migrant groups compared with the majority group. This minority-group disadvantage cannot be explained by sociodemographic or cultural variables. Future research should include minority groups in empirical studies on awareness about fertility in order to better understand the causes of this disadvantage, and the potential reproductive needs of migrants.}, language = {en} } @inproceedings{Hoeller, author = {H{\"o}ller, Christoph}, title = {Review and Comparison of ASTM and ISO Standards on Sound Transmission in Buildings}, series = {Impact of noise control engineering : 47th International Congress and Exposition on Noise Control Engineering (INTERNOISE 2018) : Chicago, Illinois, USA, 26-29 August 2018}, booktitle = {Impact of noise control engineering : 47th International Congress and Exposition on Noise Control Engineering (INTERNOISE 2018) : Chicago, Illinois, USA, 26-29 August 2018}, publisher = {Curran Associates, Inc.}, address = {Red Hook, NY}, language = {en} } @misc{Hartmann, author = {Hartmann, Julia}, title = {Developing future competencies by combining case-based learning, knowledge nuggets and gamification}, language = {en} } @article{ReinkerBlaesingBierletal., author = {Reinker, Lukas and Bl{\"a}sing, Dominic and Bierl, Rudolf and Ulbricht, Sabina and Dendorfer, Sebastian}, title = {Correlation of Acceleration Curves in Gravitational Direction for Different Body Segments during High-Impact Jumping Exercises}, series = {sensors}, volume = {23}, journal = {sensors}, number = {4}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s23042276}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-58217}, abstract = {Osteoporosis is a common disease of old age. However, in many cases, it can be very well prevented and counteracted with physical activity, especially high-impact exercises. Wearables have the potential to provide data that can help with continuous monitoring of patients during therapy phases or preventive exercise programs in everyday life. This study aimed to determine the accuracy and reliability of measured acceleration data at different body positions compared to accelerations at the pelvis during different jumping exercises. Accelerations at the hips have been investigated in previous studies with regard to osteoporosis prevention. Data were collected using an IMU-based motion capture system (Xsens) consisting of 17 sensors. Forty-nine subjects were included in this study. The analysis shows the correlation between impacts and the corresponding drop height, which are dependent on the respective exercise. Very high correlations (0.83-0.94) were found between accelerations at the pelvis and the other measured segments at the upper body. The foot sensors provided very weak correlations (0.20-0.27). Accelerations measured at the pelvis during jumping exercises can be tracked very well on the upper body and upper extremities, including locations where smart devices are typically worn, which gives possibilities for remote and continuous monitoring of programs.}, language = {en} } @article{SteffensSuhrke, author = {Steffens, Oliver and Suhrke, Michael}, title = {Novel spin features in Raman spectra of few-electron quantum dots}, series = {Physical Review Letters}, volume = {82}, journal = {Physical Review Letters}, number = {19}, publisher = {American Physical Society}, doi = {10.1103/PhysRevLett.82.3891}, pages = {3891 -- 3894}, abstract = {We employ a self-consistent, dynamic spin-density functional concept beyond the dipole approximation in order to calculate the collective modes of few-electron quantum dots with partial spin polarization. Because of Hund's rule in a magnetic field the mode energies exhibit characteristic discontinuities in their magnetic-field dependence, which is a manifestation of ground-state transitions between different spin configurations. A finite ground-state spin density couples collective charge- and spin-density excitations. We predict their observability in state-of-the-art Raman experiments.}, language = {en} } @inproceedings{TschurtschenthalerKrenkelSchreiner, author = {Tschurtschenthaler, Karl and Krenkel, Lars and Schreiner, Rupert}, title = {Mechano-optical micro pillar sensor for biofluidmechanic wall shear stress measurements}, series = {25th Congress of the European Society of Biomechanics (ESB), July 7-10, 2019, Vienna, Austria}, booktitle = {25th Congress of the European Society of Biomechanics (ESB), July 7-10, 2019, Vienna, Austria}, language = {en} } @incollection{SteffensSuhrkeRoessler, author = {Steffens, Oliver and Suhrke, Michael and R{\"o}ssler, Ulrich}, title = {Ground state and collective excitations of quantum dots: Correlation effects and Hund's rule in magnetic field}, series = {Advances in Solid State Physics}, volume = {39}, booktitle = {Advances in Solid State Physics}, editor = {Kramer, Bernhard}, publisher = {Friedr. Vieweg \& Sohn}, address = {Braunschweig}, isbn = {978-3-540-44553-1}, doi = {10.1007/BFb0107469}, pages = {111 -- 120}, abstract = {We review ground-state properties and collective excitations of semiconductor quantum dots in a magnetic field obtained from current-spin density-functional theory. Due to exchange-correlation, a generalized Hund's rule in magnetic field can be established which leads to spin alignment in partially occupied energy shells at the Fermi energy. This results, in distinct spin structures in single-electron addition spectra. Current-dependent exchange-correlation modifies the magnetic-field dependence of the ground state configuration and leads to deviations from plain spin-density calculations. Moreover it gives rise to spontaneous current textures at zero magnetic field. Collective excitation spectra, explicitly calculated for inelastic light scattering, exhibit novel features in their magnetic field dependence due to a finite ground-state spin density.}, language = {en} } @misc{SteffensSaller, author = {Steffens, Oliver and Saller, Tobias}, title = {Restaurierungskonzepte f{\"u}r St. Oswald in Regensburg}, language = {de} } @unpublished{MenzelYehKammleretal., author = {Menzel, Andreas and Yeh, Wang-Chi Vincent and Kammler, Martin and Hupalo, Myron and Conrad, E. H. and Tringides, Michael C.}, title = {Measurements of the kinetic barriers controlling the formation of the uniform height islands in Pb/Si(111)}, abstract = {As demonstrated with SPA-LEED and STM uniform height islands of preferred thickness form during the growth of Pb on Si(111). The islands form at temperatures T<250K and for fluxes F 1/60ML/sec which requires fast kinetics and balance between several atomic processes: diffusion towards the islands , diffusion to higher layers and preference for the atoms to remain on top of the preferred height islands. We have carried out SPA-LEED experiments to measure the barriers of the processes: we prepare an initial predominantly 5-step island height distribution and we deposit an additional 0.5ML Pb at different growth temperatures Tg to determine the transition to the next preferred height of 7-step islands (i.e. 2-step islands on top of the 5-step islands) with Spot Profile Analysis(SPA-LEED). We observe that 7-step island formation is possible above a minimum temperature Tg*=175K which indicates that the transfer of atoms from the surrounding region to the top of the islands is the main controlling process.}, language = {en} } @unpublished{CavalleriSidersTothetal., author = {Cavalleri, Andrea and Siders, Craig and Toth, Csaba and Squier, Jeff A. and Barty, C. P. J. and Wilson, K. R. and Sokolowski-Tinten, Klaus and von der Linde, Dietrich and Kammler, Martin and Horn- von Hoegen, Michael}, title = {Measurement of harmonic and anharmonic semi-conductor-lattice dynamics with ultrafast x-ray diffraction}, abstract = {Many fundamental processes in solids, such as heat transport and phase transitions involve atomic movement on ultrafast time-scales, but cannot be directly measured with visible light. Using ultrafast x-ray diffraction, atomic motion can be measured on its natural time-scale. Photo-excitation of bulk and layered semiconductors was achieved with 800-nm wavelength femtosecond laser pulses. Optical excitation triggers a chain of relaxation processes, causing rapid lattice heating, generation and propagation of stress/strain waves into the bulk and eventual anharmonic decay of coherent acoustic phonons into the thermal bath of the solid. While the first steps of carrier relaxation, excitation and decay of Raman-active optical phonons have been in the past characterized optically at surfaces, the bulk acoustic dynamics at longer times has not. We measure length scales of lattice excitation, thereby detecting ultrafast heat diffusion via fast electrons, coherent acoustic pulse propagation into the bulk or across buried interfaces and anharmonic damping of non-equilibrium acoustic phonons. The measurement is performed with sensitivity on lattice spacing of 10 femtometers (i.e., 3 nuclear diameters).}, language = {en} } @article{BiekerRoustaieSchlaaketal., author = {Bieker, Johannes and Roustaie, Farough and Schlaak, Helmut F. and Langer, Christoph and Schreiner, Rupert and Lotz, Marcel and Wilfert, Stefan}, title = {Field emission characterization of in situ deposited gold nanocones with variable cone densities}, series = {Journal of Vacuum Science and Technology B}, volume = {36}, journal = {Journal of Vacuum Science and Technology B}, number = {2}, publisher = {AIP Publishing}, doi = {10.1116/1.5009504}, abstract = {For the fabrication of field emitter cathodes with metallic nanocones, an in situ fabrication technique based on electrodeposition in an ion track etched polymer template was used. Three samples with nanocones made of gold and different cone densities were deposited on a circular electrode with a diameter of 2.5 mm, using templates with pore density of 6 × 104, 4 × 105, and 1 × 106 cones/cm2. The cones had a height of 24 μm, a base diameter between 3 and 3.75 μm, and a tip diameter below 500 nm. Integral field emission measurements revealed onset fields of down to 3.1 V/μm and average field enhancement factors of up to 1240. For one sample, the maximum emission current from the cathode reached 142.2 μA at an applied voltage of 338 V between cathode and extraction grid, which had a distance of 50 μm. To investigate the stability of the field emission current, cumulative long-term measurements were performed for over 50 h. A stable emission current of (31.0 ± 1.3) μA at an average applied voltage of 290 V (E = 5.8 V/μm) was observed. For currents above 100 μA, a decrease of the current and therefore a degradation of the emitter structures occurred.}, language = {en} } @inproceedings{DamsSchreiner, author = {Dams, Florian and Schreiner, Rupert}, title = {A high thermal resistance MEMS-based Pirani vacuum sensor chip}, series = {Smart sensors, actuators and MEMS VI : 24 - 26 April 2013, Grenoble, France / [part of SPIE microtechnologies]}, booktitle = {Smart sensors, actuators and MEMS VI : 24 - 26 April 2013, Grenoble, France / [part of SPIE microtechnologies]}, publisher = {SPIE}, address = {Bellingham, Wash.}, doi = {10.1117/12.2017345}, abstract = {The performance of thermal conductivity vacuum gauges can be improved by a well-designed geometry. The lower measurement range limit is determined by the size of the active sensing area and the thermal conduction heat losses through the supporting structures. The upper measurement range is limited by the distance between the heated element and the cold reference plane. Silicon based MEMS-technology gives the possibility to fabricate both sensing structures with suitable areas out of low thermal conductive materials and narrow gaps in order to extend the measurement range in both directions. In this work we present a MEMS-process to fabricate high thermal resistance sensor structures. The rectangular sensitive areas are anchored by four beams and are structured out of low thermal conductive PECVD-siliconnitride films with 1 µm in thickness. The metallic heating structure is completely embedded in the SiN-layer. Both sensitive area and its support beams were released from the silicon bulk material by anisotropic underetching. In this way a free-supporting structure with a gap of 150 μm to the silicon substrate was formed. The influence of the filament geometry and temperature was systematically investigated to determine the properties of the chips as thermal conductivity vacuum gauges. The temperature of the sensitive area was held constant by a self-balancing bridge circuit and the heating power was measured by a Δ-Σ-ADC. The average solid state thermal conductivity is in the order of 106WK1. The measuring range of the most sensitive structures covers 8 orders of magnitude from 105 mbar to 1000mbar.}, language = {en} } @article{KoenigGuertler, author = {Koenig, Eric and Guertler, Katherine}, title = {One Size Does Not Fit All: Individuality and Perceptions of Improvement and Satisfaction Among TE Students}, series = {English Teaching \& Learning}, volume = {45}, journal = {English Teaching \& Learning}, number = {3}, publisher = {Springer Science and Business Media}, issn = {1023-7267}, doi = {10.1007/s42321-021-00076-4}, pages = {303 -- 324}, abstract = {Academic self-regulation is a key factor for motivation and learning achievement. Yet with the large range of individual factors, this is not a one-size-fits-all proposition. This study of L2 Technical English students at two German universities explored learners' expectations and motivations, in particular regarding self-regulation and self-efficacy via the individual's time investment in self-led study. In an initial survey, learners (N=1646) reported on their English skill levels and anticipated learning habits. Complementarily, the retrospective survey investigated learners' (N=796) actual behavior during the course, their perceptions of language skill improvement, and their satisfaction. The initial survey indicates a clear understanding that time investment in self-regulated study will lead to greater improvement, an outcome confirmed in the retrospective survey. Additionally, students who invested more time in their coursework were more satisfied with their achievement, although most learners acknowledge they should have studied more. The results verify that learners recognize the nexus between self-regulation and language skill improvement, yet university students are not satisfied with their capacity to self-regulate their language learning strategies. While differences in students' skill levels and academic self-efficacy result in divergent degrees of progress, students of all types report benefits to their language skills when motivated to self-regulated study.}, language = {en} } @article{StierstorferWellnitzSteffens, author = {Stierstorfer, Johannes and Wellnitz, Felix and Steffens, Oliver}, title = {Conservation of historic building fabric through integrated building research and digital simulation}, series = {Bauphysik}, volume = {39}, journal = {Bauphysik}, number = {2}, publisher = {ERNST \& SOHN}, doi = {10.1002/bapi.201710016}, pages = {135 -- 143}, abstract = {The abbey of Weltenburg monastery, a late baroque icon, designed by the Asam brothers and today's world heritage, has been subject to a constant need for repair and restoration due to its geological, climatological, and exposed location on the banks of the river Danube. To solve the hygric problems within the church, an exceptional restoration concept has been executed in the last decade. This research project analyses and verifies the building-physical and indoor climatic effects of the restoration measures with focus on the improvement of the central space climate. With this case study the question is raised whether appropriate measures exist that allow a contemporary and sustainable usage of historic buildings with respect to the preservation of the historic building fabric.}, language = {en} } @misc{DuesbergBachmannEdleretal., author = {D{\"u}sberg, Felix and Bachmann, Michael and Edler, Simon and Pahlke, Andreas and Langer, Christoph and Prommesberger, Christian and Schreiner, Rupert and Bunert, Erik and Wendt, Cornelius and Zimmermann, Stefan}, title = {Novel Non-Radiative Electron Source}, series = {43rd International Symposium of Capillary Chromatography \& 16h GC x GC Symposium 2019}, journal = {43rd International Symposium of Capillary Chromatography \& 16h GC x GC Symposium 2019}, abstract = {Recently a non-radioactive electron capture detector based on a thermionic electron emitter has been demonstrated [1]. Using field emitter arrays (FEAs) would yield non-radioactive portable low power devices with fast switching capability. By combining FEAs with a vacuum-sealed housing and an electron transparent membrane window, such electron sources can be operated in an ambient pressure environment.}, language = {en} } @inproceedings{BerndtLindnerSchreineretal., author = {Berndt, Dominik and Lindner, Matthias and Schreiner, Rupert and Pipa, Andrei V. and Hink, R{\"u}diger and Brandenburg, Ronny and Foest, R{\"u}diger and Geils, Judith and Sander, Aljoscha and Hoffmann, Florian and Matz, Daniel and Baars, Albert and Kesel, Antonia and Max, Alexander and Caspari, Ralf}, title = {Realization of Multifunctional Surfaces Containing MEMS-based DBD Plasma Actuators and Biomimetic Structures for Flow Manipulation}, series = {AIAA Aviation 2019 Forum, 2019, Dallas}, booktitle = {AIAA Aviation 2019 Forum, 2019, Dallas}, publisher = {American Institute of Aeronautics and Astronautics, Inc}, doi = {10.2514/6.2019-2999}, language = {en} } @inproceedings{PrommesbergerLangerSchreiner, author = {Prommesberger, Christian and Langer, Christoph and Schreiner, Rupert}, title = {Stable and low noise field emission from single p-type Si-tips}, series = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, booktitle = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, publisher = {IEEE}, doi = {10.1109/IVNC.2018.8520018}, pages = {1-2}, abstract = {Single gated p-type Si-tips with two different tip radii were fabricated. An emission current of 2.40 μA was measured for the sharp-edged tip at a voltage of 170 V. In contrast, a stable and reproducible emission behavior was observed with an increased tip radius resulting in a pronounced saturation region between 90 V and 150 V, but merely an emission current of 0.55 μA at 150 V. More remarkable is the stable emission behavior with fluctuation of ± 4 \% during a measurement period of 30 minutes. The integral emission current in a homogeneous tip array (16 emitters) showed nearly the same I-V characteristics compared to the single tip and is therefore, most dominated by only a stable single tip in the array.}, language = {en} } @inproceedings{LindnerBerndtPrommesbergeretal., author = {Lindner, Matthias and Berndt, Dominik and Prommesberger, Christian and Langer, Christoph and Schreiner, Rupert}, title = {Field emission assisted micro plasma discharges at vacuum and atmospheric pressures}, series = {31st International Vacuum Nanoelectronics Conference (IVNC), 2018, Kyoto, Japan}, booktitle = {31st International Vacuum Nanoelectronics Conference (IVNC), 2018, Kyoto, Japan}, doi = {10.1109/IVNC.2018.8520181}, pages = {2}, abstract = {Spatially confined non-equilibrium plasmas at vacuum and atmospheric pressure in the dimensions from a few microns to one millimeter are a promising approach to the generation and maintenance of stable glow discharges. The realization of these micro-discharges or micro-plasmas enable more accurate investigations in the field of micro plasma research. We report on field emission assisted micro plasmas excited by an alternating current with frequencies up to 1 kHz. Due to the field enhancement caused by an array of Si nano-tip structures the ignition voltage of stable plasma discharges can be reduced by 30\%.}, language = {en} }