TY - JOUR A1 - Mitzkus, Anja A1 - Sahre, Mario A1 - Reinstädt, Philipp A1 - Griepentrog, Michael A1 - Beck, Uwe A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Basedau, Frank A1 - Hofmann, Detlef A1 - Gong, Xin A1 - Schukar, Vivien T1 - Altbekannter Watts-Elektrolyt, junge Hightech-Anwendung, Nickel- und Nickel-Eisen-Schichten als magnetostriktive Aktorschicht auf faseroptischen Sensoren N2 - Durch faseroptische Sensoren können Bauteile im Einsatz kontinuierlich überwacht und frühzeitig Informationen über Materialveränderungen gewonnen werden. Mittels einer magnetostriktiven Aktorschicht, welche den Sensor umhüllt, kann nun auch die korrekte Sensorfunktion jederzeit kontrolliert werden. Als Aktorschicht eignet sich galvanisch abgeschiedenes reines Nickel oder Nickel-Eisen in der Zusammensetzung 50:50. Um diese haftfest mit dem Sensor zu verbinden wurde ein ECD/PVD-Kombinationsschichtsystem entwickelt. Die mechanischen Eigenschaften der ECD-Schicht können sowohl mit einer auf die Fasergeometrie angepassten instrumentierten Eindringprüfung als auch einem 2-Punkt-Biegeversuch bestimmt werden. KW - Faseroptik-Sensoren KW - ECD-Aktorschicht KW - PVD-Haftfestigkeit KW - Nickel-/Nickel-Eisen- Magnetostriktion PY - 2016 SN - 2195-5891 SN - 2195-5905 VL - 12 SP - 1 EP - 4 AN - OPUS4-39129 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann, Michael T1 - Determination of Radon Exhalation Rates from Construction Materials using Emission Test Chambers T2 - BAM PhD Students Day 2015 CY - Berlin, Germany DA - 2015-07-14 PY - 2015 AN - OPUS4-34405 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lay, Vera A1 - Mielentz, Frank A1 - Prabhakara, Prathik A1 - Baensch, Franziska A1 - Johann, Sergej A1 - Hofmann, Detlef A1 - Sturm, Patrick A1 - Stamm, Michael A1 - Niederleithinger, Ernst T1 - Multi-sensory monitoring and ultrasound for quality assurance at underground sealing structures N2 - Within the safety concepts of underground disposal sites of nuclear waste, engineered barriers play an important role. As these sealing structures have high demands concerning integrity, we aim at advancing the available construction materials, monitoring, and inspection techniques within the project SealWasteSafe. A specifically developed alkali-activated material is compared to classical salt concrete. A comprehensive multi-sensory monitoring scheme is used at 150-340 l specimens to monitor setting and hardening of both materials. All sensors are demonstrated to resist the highly alkaline environments. Besides cabled and wireless temperature and humidity of the materials, strain variations using fibre optic sensors and acoustic emissions are recorded over periods of at least 28 days, partly for more than eight months. After hardening of the specimens, further nondestructive evaluations using ultrasonic echo and thermographic measurements are conducted. Preliminary results proof the suitability of the tested sensors and clearly highlight differences between the tested materials. Particularly, the newly developed alkali-activated material shows lower acoustic emission activity indicating less cracking activity. Additionally, unique ultrasonic methods will enable better images of potential internal objects and cracks at in-situ sealing structures. A largescale ultrasonic system is optimised to reliably detect objects at a depth exceeding 9 m while still obtaining a good resolution. Modelling studies show the potential of further increasing the distance between individual transducer arrays. Additionally, a new ultrasonic borehole probe using phased arrays allowing for beam focussing is constructed and tested. Laboratory measurements at a halfcylindrical concrete specimen coincide well with the previous modelling. In total, the presented safe materials, detailed monitoring approaches and ultrasonic quality assurance methods will help to obtain safe sealing structures within salt as a host rock. The concepts can partly be transferred to sealing structures in alternative host rocks and will also be valuable for non-nuclear waste repositories. T2 - NDE NucCon CY - Espoo, Finland DA - 25.01.2023 KW - SealWasteSafe KW - Engineered barriers KW - Monitoring KW - Embedded sensors KW - Ultrasonic imaging PY - 2023 SP - 2 EP - 10 AN - OPUS4-56928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann, Michael A1 - Richter, Matthias A1 - Jann, Oliver T1 - Determination of radon exhalation from building materials in dynamically operated test chambers by use of commercially available measuring devices N2 - The inhalation of radon (222Rn) decay products is the leading cause of lung cancer apart from tobacco smoking. Besides the permeation of radon from the subsoil through the basement as main source of radon in indoor air, also building materials have to be taken into consideration, especially at low air change rates in buildings. The Construction Products Regulation (EC, 2010) gives essential requirements for construction works regarding the release of dangerous substances such as toxic gases and radiation to which radon can be assigned. The recently adopted Basic Safety Standards Directive (EC, 2013), which has to be ratified by each European member state in between the next three years sets reference levels for indoor radon concentrations for the first time. In research project financed by the German Ministry for the Environment, Nature Conservation, Building and Nuclear Safety a practical, reliable and easily applicable test procedure for the determination of radon exhalation from building materials – based on ISO 16000-9 (ISO, 2006) and CEN/TS 16516 (CEN, 2013) – should be developed. In contrast to the static test procedure published by Richter et al. (2013), dynamically operated test chambers shall be foregrounded. First results of this study are presented, focused on the reliable measurement of radon background concentration and the selection of suitable radon test devices, representing the basic elements of the subsequent work. T2 - Healthy Buildings Europe 2015 CY - Eindhoven, The Netherlands DA - 18.05.2015 KW - Radon exhalation KW - Building material KW - VOC emission test chamber KW - Radon measurement PY - 2015 SN - 978-90-386-3889-8 SP - Paper 552, 1 EP - 3 AN - OPUS4-35011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann, Michael T1 - Determination of Radon Exhalation Rates from Construction Materials using Emission Test Chambers T2 - Healthy Buildings 2015 Europe CY - Eindhoven, Netherlands DA - 2015-05-18 PY - 2015 AN - OPUS4-34406 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann, Michael T1 - Prüfverfahren zur Bestimmung der Radon-Exhalationsrate aus Bauprodukten in VOC-Emissionskammern N2 - Es wurden die wesentlichen Ergebnisse des abgeschlossenen UFOPLAN-Vorschungsvorhabens "Methodische Untersuchungen zur Qualifizierung der VOC-Kammern zur Bestimmung der Radonexhalationsrate von Bauprodukten, Los 1" vorgestellt. Das entwickelte Prüfverfahren eignet sich zur Bestimmung der Radonexhalationsrate von Bauprodukten mittels kommerziell erhältlicher Radon-Messtechnik in dynamisch betriebenen VOC-Emissionsprüfkammern. Es ist robust gegenüber einem weiten Bereich von Parametereinstellungen hinsichtlich der Prüfparameter Prüfkammervolumen, Produktbeladung, Luftwechselrate und flächenspezifische Luftdurchflussrate. Entscheidend für die Messung im Bereich geringer Radonaktivitätskonzentration ist es, die Zuluftkonzentration (Blindwert) der Emissionsprüfkammern auf einem konstant geringen Niveau zu halten oder durch eine – zur eigentlichen Baustoffmessung – parallele Messung der Zuluft zu kompensieren. Die gängige Aufbereitung der Zuluft der VOC-Prüfkammern mittels mehrfacher Filtration und Sorption über Silica-Gel- sowie verhältnismäßig kleinvolumigen Aktivkohle-Filtern ist bezüglich Radon unwirksam. T2 - 11. Radon-Fachgespräch CY - Berlin, Germany DA - 02.03.2017 KW - Radon KW - Exhalationsrate KW - Bauprodukt KW - VOC-Emissionsprüfkammer KW - Prüfverfahren PY - 2017 AN - OPUS4-39334 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hofmann, Michael A1 - Richter, Matthias A1 - Jann, Oliver T1 - Use of commercial radon monitors for low level radon measurements in dynamically operated VOC emission test chambers N2 - Compared to the intended EU reference level of 300 Bq m−3 for indoor radon concentrations, the contribution of building materials appears to be low. Considering the recommended limit of 100 Bq m−3 by WHO, their contribution is supposed to be relevant, especially at low air exchange rates. This study as part of a two-part research project investigated the suitability of direct low level 222Rn measurement under simulated indoor conditions with commercial radon monitors and dynamically operated emission test chambers. Active measuring devices based on ionisation or scintillation chambers with 1-σ uncertainties below 8.6% at 20 Bq m−3 were found to be best suitable for a practical test procedure for the determination of radon exhalation rates of building materials. For the measurement of such low concentrations, the knowledge of the accurate device background level is essential. KW - Radon monitors KW - Radon exhalation KW - Building materials KW - Measurement method PY - 2017 DO - https://doi.org/10.1093/rpd/ncx137 SN - 1742-3406 SN - 0144-8420 VL - 177 IS - 1-2 SP - 16 EP - 20 PB - Oxford Academic AN - OPUS4-41952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hofmann, Michael A1 - Richter, Matthias A1 - Jann, Oliver T1 - Robustness validation of a test procedure for the determination of the radon-222 exhalation rate from construction products in VOC emission test chambers N2 - This study investigated the adaptation of the state-of-the-art test procedure for the determination of emissions of volatile organic compounds (VOC) from materials into indoor air to test for the radon exhalation from stony construction products. A complete robustness validation including all relevant parameters showed that the procedure can be well applied by testing institutes already holding available the required VOC testing infrastructure that solely needs to be complemented by calibrated commercial radon measurement instrumentation. When measurements of the radon exhalation from construction materials become mandatory by law, test capacity can easily be applied. This work can serve as a recommendation for the European standardisation that still is on hold in this point. KW - Radon exhalation KW - Construction products KW - Emission test chamber KW - Robustness validation KW - Standardisation PY - 2020 DO - https://doi.org/10.1016/j.apradiso.2020.109372 SN - 0969-8043 VL - 166 IS - 109372 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-51145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Genath, A. A1 - Hofmann, Michael A1 - Tiebe, Carlo A1 - Einspanier, R. T1 - Auf dem Weg zum Monitoring der Ameisensäurekonzentration in der Bienenstock-Luft mit einem Multigassensorsystem N2 - Die Varroose gilt weltweit als eine der bedeutendsten Erkrankungen der westlichen Honigbiene, Apis mellifera. Verursacht wird sie durch den Ektoparasiten Varroa destructor, der durch Saugen der Hämolymphe und Virenübertragung sowohl die Bienenbrut als auch die adulten Individuen schädigt. Ohne imkerliche Unterstützung gehen betroffene Bienenvölker in der Regel innerhalb von drei Jahren ein. Als bewährte, häufige Behandlung wird flächendeckend 60%ige Ameisensäure (AS) - im Bienenstock appliziert über verschiedene Verdampfungssysteme - eingesetzt. Sie wirkt als einziger zugelassener Stoff gegen die Varroamilbe auch in die verdeckelte Brut hinein und birgt kein Risiko der Resistenzentwicklung. Allerdings ist das therapeutische Fenster, der Bereich zwischen Milbenabtötung und Bienenschädigung, relativ schmal und die tatsächliche AS-Konzentration im Bienenstock stark abhängig von äußeren Einflussfaktoren, wie Temperatur, Luftfeuchte oder Applikationsart. Eine Bestimmung der exakten AS-Konzentration im Bienenstock ist also notwendig, um einerseits das Wirkungsoptimum zu bestimmen und andererseits bei Übersteigen der Maximalkonzentrationen mit Folge-Schädigung der Bienen, ein rechtzeitiges Eingreifen der Imker zu ermöglichen. T2 - 6. HSN-Fachsymposium „Innovative Sensorik, verteilte Sensorsysteme, neue Technologien und Anwendungsfelder“ CY - Karlsruhe, Germany DA - 06.11.2019 KW - Biene KW - Apis mellifera KW - Varroa destructor KW - Ameisensäure KW - Multigassensorik PY - 2019 AN - OPUS4-49606 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Genath, A. A1 - Hofmann, Michael A1 - Tiebe, Carlo A1 - Einspanier, R. T1 - Proof-of-concept trial of the portable electronic nose PEN3 for detection of formic acid concentration in the beehive N2 - Formic acid (FA) treatment as measure against the ectoparasitic mite, Varroa destructor, which infests the western honey bee, Apis mellifera, is usually performed twice a year. Although the therapeutic index is very narrow and the success of FA-treatment is highly dependent on various external factors, little is known about the local FA concentrations occuring in the hive. In this study we examined whether a commercially available odour measuring device (“electronic nose”) is suitable for measurements of high FA concentrations, as present during treatment. As measuring systems, two different setups were prepared for detection of FA concentrations in gas mixtures: A polymethyl methacrylate (PMMA) box was used to investigate whether the electronic nose is able to distinguish between different FA concentrations and a two-storied Segeberger hive to test under realistic conditions during bee-keeping. In both experimental systems, the signals from the same sensor components (sensor type no. 1, 6, 7, 8 and 9) showed an increased sensitivity towards the presence of FA in the gas mixture. Principle component analysis (PCA) and linear discriminant analysis (LDA) allowed for identification of specific patterns in the measurement signals and showed clear correlations between the signals and the present FA concentration. These results indicate that the introduced commercial multi gas sensor system is suitable for detection of high FA concentrations, and therefore could be a starting point developing a detection method of FA. The future aim is to successfully monitor the efficiency and effectiveness of this anti-varroa-treatment. T2 - 20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019 CY - Nuremberg, Germany DA - 25.06.2019 KW - Apis mellifera KW - Varroa destructor KW - Formic Acid KW - Metal-Oxide Gas Sensor Array PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483812 UR - https://www.ama-science.org/proceedings/details/3430 DO - https://doi.org/10.5162/sensoren2019/P3.10 VL - 2019 SP - 794 EP - 799 AN - OPUS4-48381 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -