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Eingeladener Vortrag
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The combination of Radio-frequency identification (RFID) and low energy sensors offers promising chances to implement cost effective, easy to apply, and easy to handle sensor systems for a variety of applications. The RFID technology is already well established in logistics. Enhanced processing and interface capabilities enable the integration of various sensors for control, diagnostics, and monitoring tasks. In the scope of research projects carried out at the Federal Institute for Materials Research and Testing (BAM), RFID sensor systems were developed and validated with regard to two different application scenarios: the Identification and diagnosis of concrete components for road bridges and the monitoring of dangerous goods transportation. This contribution presents selected research results and reflects the practical experiences on future chances and limitations of RFID sensor systems.
Completely embedded sensor systems for long-term operation offer innovative possibilities for structural health monitoring of concrete structures. Measuring of relevant parameters, e.g., temperature, humidity, or indication of corrosion can be performed with low energy sensors. This allows to implement passive RFID sensor systems without cable connection and battery, which are power supplied exclusively by the electromagnetic field from the external reader device. To evaluate characteristics and conditions of this concept, a systematical investigation of the transmission characteristics with variation of relevant parameters, as communication frequency, installation depth, type of concrete, moisture content, etc. is currently carried out in an interdisciplinary Research project at BAM. First results are presented in this paper.
BAM is the German Federal Institute for Materials Research and Testing and the competent authority for mechanical and thermal safety assessment of transport packages for spent fuel and high level waste. In context with safety assessment of RAM packages BAM performed numerous drop tests in the last decades. The tests were mostly accompanied by extensive and various measurement techniques especially by instrumented measurements with strain gages and accelerometers. The procedure of drop testing and the resulting measurement analysis are the main methods to evaluate the safety against mechanical test conditions. Measurement techniques are dedicated to answer questions in regard to the structural integrity of a RAM package, the mechanical behavior of the prototype as well as of its content under impact conditions.
Test results like deceleration-time functions constitute a main basis for the validation of assumptions in the safety analysis and for the evaluation of numerical calculations. In this context the adequate selection of accelerometers and measurement systems for the performance of drop tests is important. Therefore it is not only necessary to find suitable positions for the accelerometers at the test specimens, but also to consider technical boundary conditions as e.g. temperature.
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.
Insect behavior is a common source of inspiration for roboticists and computer scientists when designing gas-sensitive mobile robots. More specifically, tracking airborne odor plumes and localization of distant gas sources are abilities that suit practical applications such as leak localization and emission monitoring. Gas sensing with mobile robots has been mostly addressed with ground-based platforms and under simplified conditions and thus, there exist a significant gap between the outstanding insect abilities and state of the art robotics systems. As a step towards practical applications, we evaluated the performance of three biologically inspired plume tracking algorithms. The evaluation is carried out not only with computer simulations, but also with real-world experiments in which, a quadrocopter-based micro Unmanned Aerial Vehicle autonomously follows a methane trail towards the emitting source. Compared to ground robots, micro UAVs bring several advantages such as their superior steering capabilities and fewer mobility restrictions in complex terrains. The experimental evaluation shows that, under certain environmental conditions, insect like behavior in gas-sensitive UAVs is feasible in real world environments.
Es wird ein vereinfachtes Verfahren für die Bestimmung und Implementierung der Maschinennachgiebigkeit bei der Verwendung eines sphärischen Indenters dargestellt. Die Maschinennachgiebigkeit wird bei deutlicher Kraftabhängigkeit als Funktion der Kraft in die Auswertung implementiert. Als sensitiver Kennwert dient der aus der instrumentierten Eindringprüfung an Härtevergleichsplatten ermittelte Eindringmodul.
Temperature characteristics of a piezoresistive accelerometer for high impact shock application
(2018)
This study presents the characterization of a piezoresistive accelerometer damped with silicon oil for the application in drop tests carried out at BAM. Experiments were performed with the Hopkinson Bar method in close correlation to the real-world application conditions. The results point out certain limitations regarding the temperature influence and the frequency response. Additional experiments were performed with a gas damped type of piezoresistive accelerometer, which has superior specifications, particularly for low temperatures. The results allow for a comparison.
Temperature characteristics of a piezoresistive accelerometer for high impact shock application
(2018)
This study presents the characterization of a piezoresistive accelerometer damped with silicon oil for the application in drop tests carried out at BAM. Experiments were performed with the Hopkinson Bar method in close correlation to the real-world application conditions. The results point out certain limitations regarding the temperature influence and the frequency response. Additional experiments were performed with a gas damped type of piezoresistive accelerometer, which has superior specifications, particularly for low temperatures. The results allow for a comparison.
Leaking methane (CH4) from infrastructures, such as pipelines and landfills, is critical for the environment but can also pose a safety risk. To enable a fast detection and localization of these kind of leaks, we developed a novel robotic platform for aerial remote gas sensing. Spectroscopic measurement methods for remote sensing of selected gases lend themselves for use on mini-copters, which offer a number of advantages for inspection and surveillance over traditional methods. No direct contact with the target gas is needed and thus the influence of the aerial platform on the measured gas plume can be kept to a minimum. This allows to overcome one of the major issues with gas-sensitive mini-copters. On the other hand, remote gas sensors, most prominently Tunable Diode Laser Absorption Spectroscopy (TDLAS) sensors have been too bulky given the payload and energy restrictions of mini-copters. Here, we present the Unmanned Aerial Vehicle for Remote Gas Sensing (UAV-REGAS), which combines a novel lightweight TDLAS sensor with a 3-axis aerial stabilization gimbal for aiming on a versatile hexacopter. The proposed system can be deployed in scenarios that cannot be addressed by currently available robots and thus constitutes a significant step forward for the field of Mobile Robot Olfaction (MRO). It enables tomographic reconstruction of gas plumes and a localization of gas sources. We also present first results showing its performance under realistic conditions.
Pollution through emission of toxic gases is an increasing problem for the environment. It affects similarly agricultural, industrial and urban areas. In future, environmental emissions in ambient air must be monitored at even lower concentrations as nowadays. One environmental relevant compound is ammonia and its conversion product ammonium that have strong negative impact on human health and ecosystems. Most ammonia measurements in ambient air are performed in the range below 1000 nmol·mol 1 and thus there is a need for reliable traceable ammonia gas standards and in addition in situ analytical procedures for monitoring (in ambient air to avoid that thresholds are exceeded). Therefore, the use of reference materials is necessary for development accompanying test or for calibration, e. g. of structure-integrated sensors and mobile multi-gas sensors.
The developed gas standard generator produces gas mixtures that comply with the metrological traceability for ammonia gas standards in the desired environmentally relevant measurement range. The method is based on the permeation of ammonia through a membrane at constant temperature and pressure. The resulting ammonia penetrant gas flow is then mixed with a carrier gas flow to generate a gas standard flow of known concentration. The dynamic rage is enlarged by using a two dilution steps. Depending on the permeation rate, generable molar fractions are possible in the range nmol·mol-1 to a few µmol·mol-1. We present the design of an ammonia gas standard generator and first results of the characterisation of its individual components supporting the uncertainty assessment according to GUM for stable gas concentrations in this range. The relative uncertainty of the generated ammonia gas standard is smaller than 4 % (k = 2).
Sensor network deployment
(2018)
Im Projekt KonSens werden für die Anwendungsbei-
spiele bauteilintegrierte Sensorik für Betonkomponen-
ten und mobile Multigassensorik Sensorsysteme in
Form von Funktionsmustern entwickelt, validiert und
angewendet. Schwerpunkte liegen einerseits in der
Detektion und Bewertung von Korrosionsprozessen in
Beton und andererseits in der Detektion und Quantifi-
zierung sehr geringer Konzentrationen toxischer Gase
in der Luft. Dabei ist die Adaption der sensorischen
Methoden aus dem Labor in reale Messumgebungen
inklusive geeigneter Kommunikationstechnik ein
wichtiger Aspekt.
Innovation is the catalyst for the technology of the future. It is important to develop new and better technologies that can continuously monitor the environmental impact, e.g., for air Quality control or emission detection. In the recently at BAM developed Universal Pump Sensor Control (UPSC3) module, different components and sensors are fused. The combination of the individual components makes the UPSC3 module an excellent monitoring and reference system for the development and characterization of gas specific sensors. Measurements over long periods are possible, for mixed gas loads or for certain gas measurements. The System is part of a mobile sensor network of several sensor units, which can also be used as standalone systems.
BAM is the German Federal Institute for Materials Research and Testing and the competent authority for mechanical and thermal safety assessment of transport packages for spent fuel and high level waste. In context with safety assessment of RAM packages BAM performed numerous drop tests in the last decades. The tests were mostly accompanied by extensive and various measurement techniques especially by instrumented measurements with strain gages and accelerometers.
The procedure of drop testing and the resulting measurement analysis are the main methods to evaluate the safety against mechanical test conditions. Measurement techniques are dedicated to answer questions in regard to the structural integrity of a RAM package, the mechanical behavior of the prototype as well as of its content under impact conditions.
Test results like deceleration-time functions constitute a main basis for the validation of assumptions in the safety analysis and for the evaluation of numerical calculations. In this context the adequate selection of accelerometers and measurement systems for the performance of drop tests is important. Therefore it is not only necessary to find suitable positions for the accelerometers at the test specimens, but also to consider technical boundary conditions as e.g. temperature.
Over decades, the German Federal Institute for Materials Research and Testing (BAM) has established a sophisticated calibration laboratory for force, temperature and electrical quantities. Since more than 15 years it is accredited, currently by the national accreditation body (DAkkS), and offers its service also to external entities on a global scale. As a public provider, we are furthermore committed to research and development activities that demand measurements with highest quality and low level of uncertainties. Two R&D examples are highlighted within this contribution.
In this paper, we introduce a nano aerial robot swarm for indoor air quality monitoring applications such as occupational health and safety of (industrial) workplaces. The concept combines a robotic swarm composing of nano Unmanned Aerial Vehicles (nano UAVs), based on the Crazyflie 2.0 quadrocopter, and small lightweight metal oxide gas sensors for measuring the Total Volatile Organic Compound (TVOC) in ppb and estimating the eCO2 (equivalent calculated carbon-dioxide) concentration in ppm. TVOC is a measure for the indoor air quality. An indoor localization and positioning system will be used to estimate the absolute 3D position of the swarm like GPS. Based on this novel indoor air quality monitoring concept, the development and validation of new algorithms in the field of Mobile Robot Olfaction (MRO) are planned, namely gas source localization and gas distribution mapping. A test scenario will be built up to validate and optimize the gas-sensitive nano aerial robot swarm for the intended applications.
In this paper, we introduce a nano aerial robot swarm for Indoor Air Quality (IAQ) monitoring applications such as occupational health and safety of (industrial) workplaces. The robotic swarm is composed of nano Unmanned Aerial Vehicles (UAVs), based on the Crazyflie 2.0 quadrocopter, and small lightweight Metal Oxide (MOX) gas sensors for measuring the Total Volatile Organic Compound (TVOC), which is a measure for IAQ. An indoor localization and positioning system is used to estimate the absolute 3D position of the swarm similar to GPS. A test scenario was built up to validate and optimize the swarm for the intended applications. Besides calibration of the IAQ sensors, we performed experiments to investigate the influence of the rotor downwash on the gas measurements at different altitudes and compared them with stationary measurements. Moreover, we did a first evaluation of the gas distribution mapping performance. Based on this novel IAQ monitoring concept, new algorithms in the field of Mobile Robot Olfaction (MRO) are planned to be developed exploiting the abilities of an aerial robotic swarm.
The presence of wastewater and air pollution has become an important risk factor for citizens, not only in terms of problems related to health risks, but also because of its negative impact on the country's image. For this reason, malodorous emission monitoring and control techniques are in high demand in urban areas and industries. The aim of this work is first to build an electronic nose (e-nose) and a Voltammetric Electronic tongue (VE-tongue) in order to study their ability to discriminate between polluted and clean environmental samples. Secondly, Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS), and Solid Phase Micro Extraction-Gas Chromatography–Mass Spectrometry (SPME-GC-MS) are utilized to explain this discrimination by identifying specific compounds from these samples. Indeed, the e-nose, consisted of metal oxide semiconductor gas sensors, is used for the assessment of the studied odorous air and headspace samples from water and wastewater sites. Moreover, the VE-tongue, based on metal electrodes, is utilized to determine the patterns of the sensor array responses, which serve as fingerprints profiles of the analyzed liquid samples. Chemometric tools, such as Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Support Vector Machines (SVMs) are operated for the processing of data from the e-nose and the VE-tongue. By using the both systems, the analyses of headspace and liquid samples from the seven sites allow better discrimination. To explain the cause of the obtained discrimination, TD-GC-MS and SPME-GC-MS analyses are well performed to identify compounds related sites. According to these outcomes, the proposed e-nose and VE-tongue are proved to be rapid and valuable tools for analysis of environmental polluted matrices.
IMS trägt zur Luftfrachtsicherheit bei
Geltende Luftsicherheitsgesetze verpflichten Luftsicherheitsbehörden, Flughafenbetreiber und Fluggesellschaften umfassende Sicherheitsmaßnahmen auf den Flughäfen zu ergreifen, um die Gefahr möglicher terroristischer Bedrohungen zu erkennen und zu verhindern. Wenn ein verdächtiges Objekt durch Röntgenstrahlen identifiziert wurde, kann die IMS als schnelles Analyseverfahren vor Ort orthogonal zur Radiologie eingesetzt werden, um chemische Informationen über Gefahrstoffe wie Sprengstoffe oder Drogen vor dem Abflug zu erhalten.
Vor der Detektion von Sprengstoffen beginnt die Untersuchung eines verdächtigen Objekts mit der Probenahme mittels Wischprobensammlern. Eine Luftsicherheitskontrollkraft wischt dabei Oberflächen des Objekts mit einem Probensammler ab, um Partikel von Gefahrstoffen zu sammeln. Der beladene Probensammler wird anschließend in einen Probeneinlass eingeführt. Nach thermischer Desorption der gesammelten Stoffe erhält der Bediener (z. B. Luftsicherheitskontrollkraft) ein boolesches Ergebnis - "Alarm" oder "Kein Alarm".
Verfahren und Ergebnisse
In dieser Studie wurden drei Verfahren mit vier ECAC-zertifizierten ETD-Geräten zur Entwicklung eines Unsicherheitskonzeptes bezüglich der Probenahme (PN) angewandt:
I) direkte Probenaufnahme durch lösemittelbasierten Auftrag einer bekannten Sprengstoffmenge auf einem Probensammler,
II) Auftragung einer bekannten Menge eines gelösten Sprengstoffs auf einem 10 cm × 10 cm Substrat (Aluminium, Papier, Eisen und Polyvinylchlorid) und manuelle PN nach Lösemittelverdampfung,
III) lösemittelbasierter Sprengstoffauftrag auf eine PTFE- oder PTFE-beschichtete Glasfaseroberfläche, nach Lösemittelverdunstung trockene Übertragung auf das zu beprobende Substrat zur PN.
Nach dem binären Regressionsverfahren wurde die funktionale Abhängigkeit der Detektionswahrscheinlichkeit von einer bekannten Sprengstoffmasse mit einer Logit-Funktion beschrieben:
POD=1/(1+e^(-A·(m-B))).
Dabei ist POD die Wahrscheinlichkeit der Detektion für eine bekannte Sprengstoff-Masse, die Parameter A (logistische Wachstumsrate der Kurve) und B (m-Wert des Mittelpunktes des Sigmoids) sind geschätzte Parameter nach der Methode der kleinsten Quadrate, und m ist die Sprengstoffmasse.
Das entwickelte Messunsicherheitsmodell kombiniert quantitative Ergebnisse aus Wägen, Lösen und Pipettieren sowie qualitative Ergebnisse - "Alarm" oder "Kein Alarm" und die Unsicherheit der PN. Identifizierte Unsicherheitsursachen sind die Durchführung der Wischprobenahme, Staub, Lösemitteleffekte und die Unsicherheit bei der Herstellung von Testlösungen.
The present paper describes the development of a sensor material that changes its fluorescence in the presence of gaseous ammonia in a relevant concentration range. The implementation into a semi-automatic gas measurement device enables low-cost, precise, simple and fast monitoring of low con-centrations of harmful gases, like ammonia, and hence can help to improve the climate monitoring in livestock housing, barns or stables.