TY - JOUR A1 - Erwamati, F. U. A1 - Pratapa, S. A1 - Suasmoro, S. A1 - Hübert, Thomas A1 - Banach, Ulrich T1 - Preparation and structural study of Mg1−xZnxTiO3 ceramics and their dielectric properties from 1 Hz to 7.7 GHz N2 - A series of Mg₁₋ₓZnₓTiO₃, x = 0–0.5 (MZT0–MZT0.5) ceramics was synthesised and characterised. The dielectric properties of the samples in the frequency range of 1 Hz – 7.7 GHz were explored using three different methods: a contacting electrode method, a parallel-plate method and a perturbed resonator method. The electrical properties in the space charge and dipolar polarisation frequency ranges are discussed in relation to the phase composition and microstructure data. Differences in the zinc Substitution divided the dielectrics into two groups, namely MZT0-MZT0.2 and MZT0.3–MZT0.5, each with different amount of a main Mg₁₋ₓZnₓTiO₃ solid solution phase and a secondary solid solution phase. Zinc substitution promoted the density of the ceramics, improved the purity of the main phase and increased the permittivity for frequencies up to 10⁸ Hz, but reduced the permittivity in the microwave range. In the MZT0.3–MZT0.5 samples, for frequencies less than 1 MHz the quality (Q x ƒ) factors were lower and log σ ₐ.c, the AC conductivity, was higher than for the MZT0–MZT0.2 samples. Above 10 MHz, the (Q x ƒ) factors and log σ ₐ.c of the two groups were similar. KW - Mg1-xZnxTiO3 KW - Space charge polarisation KW - Dipole polarisation KW - Microwave frequency KW - Dielectric properties PY - 2016 DO - https://doi.org/10.1007/s10854-016-4610-6 SN - 0957-4522 VL - 27 IS - 7 SP - 6637 EP - 6645 PB - Springer CY - Dordrecht, Netherlands AN - OPUS4-36466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Boon-Brett, L. A1 - Bousek, J. A1 - Black, G. A1 - Moretto, P. A1 - Castello, P. A1 - Hübert, Thomas A1 - Banach, Ulrich T1 - Identifiying performance gaps in hydrogen safety sensor technology for automotive and stationary applications N2 - A market survey has been performed of commercially available hydrogen safety sensors, resulting in a total sample size of 53 sensors from 21 manufacturers. The technical specifications, as provided by the manufacturer, have been collated and are displayed herein as a function of sensor working principle. These specifications comprise measuring range, response and recovery times, ambient temperature, pressure and relative humidity, power consumption and lifetime. These are then compared against known performance targets for both automotive and stationary applications in order to establish in how far current technology satisfies current requirements of sensor end users. Gaps in the performance of hydrogen sensing technologies are thus identified and areas recommended for future research and development. KW - Hydrogen sensor KW - Hydrogen detection KW - Safety KW - Sensor performance testing KW - Performance specifications KW - Performance targets PY - 2010 DO - https://doi.org/10.1016/j.ijhydene.2009.10.064 SN - 0360-3199 VL - 35 IS - 1 SP - 373 EP - 384 PB - Elsevier CY - Oxford AN - OPUS4-22893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mosel, Günter A1 - Willfahrt, Manfred A1 - Banach, Ulrich A1 - Hübert, Thomas T1 - An extended X-ray absorption fine structure investigation on the local environment of niobium ions in Nb2O5-doped SrTiO3 glass ceramics PY - 1997 SN - 0022-2461 SN - 1573-4803 VL - 32 SP - 1591 EP - 1597 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-2045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübert, Thomas A1 - Boon-Brett, L. A1 - Black, G. A1 - Banach, Ulrich T1 - Hydrogen sensors - A review N2 - Hydrogen sensors are of increasing importance in connection with the development and expanded use of hydrogen gas as an energy carrier and as a chemical reactant. There are an immense number of sensors reported in the literature for hydrogen detection and in this work these sensors are classified into eight different operating principles. Characteristic performance parameters of these sensor types, such as measuring range, sensitivity, selectivity and response time are reviewed and the latest technology developments are reported. Testing and validation of sensor performance are described in relation to standardisation and use in potentially explosive atmospheres so as to identify the requirements on hydrogen sensors for practical applications. KW - Hydrogen sensors KW - Hydrogen detection KW - Detection technologies KW - Technology developments PY - 2011 DO - https://doi.org/10.1016/j.snb.2011.04.070 SN - 0925-4005 SN - 1873-3077 VL - 157 IS - 2 SP - 329 EP - 352 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-24037 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lang, M. A1 - Banach, Ulrich A1 - Nörthemann, K. A1 - Gerlitzke, A.-K. A1 - Milstrey, M. A1 - Kaufer, R. A1 - Woratz, M. A1 - Hübert, Thomas A1 - Moritz, W. T1 - Long-term stability of a MEIS low energy hydrogen sensor N2 - A hydrogen sensor based on a silicon Metal/Solid Electrolyte/Insulator/Semiconductor (MEIS) structure with thin layers of the super-ionic conductor LaF3 and Pd gate metal was investigated in a hybrid structure on a resistance heater mounted on a ceramic substrate. The sensor was operated at room temperature, however, a short heating impulse once a day ensures a fast and reproducible dynamic behavior. The sensor was characterized in the concentration range typical for alarm levels up to 40% of the lower flammability limit and shows a logarithmic dependency of the sensor signal from the hydrogen concentration and a mean sensitivity of about 140 mV/decade. The response time (t90) is about 8 s. In a long term test for a period of three month, the sensor was exposed to hydrogen every two weeks. The sensor signal was shown to be stable in dynamic behavior, sensitivity and signal difference. KW - Hydrogen detection KW - Long-term measurement KW - MEIS-structure KW - Low energy sensor PY - 2013 DO - https://doi.org/10.1016/j.snb.2012.12.081 SN - 0925-4005 SN - 1873-3077 VL - 187 SP - 395 EP - 400 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-29223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Noske, Reinhard A1 - Banach, Ulrich T1 - Multigassensorik in die Routine? PY - 2002 SN - 0016-3538 VL - 46 IS - 8 SP - 854 EP - 855 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-1605 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Banach, Ulrich A1 - Hübert, Thomas T1 - Prüfen und kalibrieren von Halbleiter-Gassensoren PY - 2001 SN - 0179-9592 VL - 6 SP - 10 EP - 12 PB - Thomas CY - St. Gallen AN - OPUS4-1914 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Banach, Ulrich A1 - Noske, Reinhard T1 - Multigassensorik auf dem Weg in die Routine PY - 2002 UR - http://www.oilgaspublisher.de/de/index.html SN - 0179-3187 VL - 18 IS - 9 SP - 411 EP - 412 PB - Urban-Verl. CY - Hamburg AN - OPUS4-1922 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Detjens, Marc A1 - Hübert, Thomas A1 - Tiebe, Carlo A1 - Banach, Ulrich T1 - Coulometric trace humidity measurement in technical gases N2 - Trace humidity was measured by using miniaturized planar coulometric sensors in technical gases such as hydrogen, nitrogen, helium, nitrous oxide, and synthetic air. Frost point temperatures tf in the gases ranged from −60 °C to −30 °C, which is equivalent to a vapour mole fraction xv from 10 μmol mol−1 to 376 μmol mol−1. In addition, the generated humidity was determined by using a precision dew point hygrometer as reference. Nonlinear calibration functions were calculated that correlated electric current (sensor signal) and reference humidity. Parameters of functions were tested with one-way analysis of variances (ANOVA) to prove if all used sensors had a similar behavior in the same gas during experiments. Results of ANOVA confirmed that averaged functions can be applied for trace humidity measurement in nitrogen, helium, nitrous oxide, and synthetic air. The calculated functions were negligibly different for nitrogen, helium, and synthetic air. In humidified nitrous oxide, a minor change of parameters was observed due to lower electrical currents. In total contrast to that, the measured sensor signals were significantly higher in humidified hydrogen and each sensor required its own calibration function. The reason was a recombination effect that favoured multiple measurements of water molecules. Nevertheless, it was possible to measure continuously trace humidity in all tested gases by using coulometric sensors with an expanded uncertainty below 2 K (k = 2). KW - ANOVA KW - Trace humdity measurement KW - Coulometric sensors KW - Chemical sensors KW - Measurement uncertainty PY - 2018 DO - https://doi.org/10.1063/1.5008463 SN - 0034-6748 SN - 1089-7623 VL - 89 IS - 8 SP - 085004, 1 EP - 8 PB - American Institute of Physics (AIP) CY - Maryland (USA) AN - OPUS4-45956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tiebe, Carlo A1 - Detjens, Marc A1 - Banach, Ulrich A1 - Hübert, Thomas T1 - Measurement uncertainty of coulometric trace humidity sensors N2 - Especially trace amounts of water vapour in gases can be reliably determined by coulometric trace humidity sensors. The principle of these sensors is based on water vapour absorption in a hygroscopic layer and its subsequent electrolytic decomposition. The calibration of sensors was performed in the humidity range, expressed as frost point temperature, from −30°C to −80°C . This range is equivalent to volume fractions smaller than 376 µL·L−1. Generated humidity was measured with coulometric sensors and a chilled dew point hygrometer that was used as reference. An empirical non-linear function was found between sensor signal and measured reference humidity. This function consists of two parameters with a measurement uncertainty. Both calibration parameters were checked by means of one-way analysis of variance. It showed that gas specific function can be used for humidity measurement in nitrogen, hydrogen, dinitrogen monoxide, compressed and synthetic air. It is possible to determine trace humidity in all tested gases with an expanded uncertainty less than 2.1 K (coverage factor k=2 ) regarding frost point temperature. KW - Trace humidity KW - Coulometric sensor KW - Measurement uncertainty KW - ANOVA PY - 2018 DO - https://doi.org/10.1515/teme-2018-0031 SN - 0171-8096 VL - 85 IS - 12 SP - 746 EP - 753 PB - De Gruyter CY - Oldenbourg AN - OPUS4-45959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Banach, Ulrich A1 - Tiebe, Carlo A1 - Hübert, Thomas T1 - Multigas sensors for the quality control of spice mixtures N2 - Spices have an important impact on daily aliment. Changes of their quality resulting in far reaching consequences in different foodstuffs and imply financial losing and even health hazard. In this study it is demonstrated that application of two different portable multi gas sensors (electronic nose and ion mobility spectrometer) supported by multivariate data analysis can contribute to ensure quality control of spice mixtures and to find out product adulteration. Headspace above spice mixtures for sausages and saveloy and product counterfeitings was investigated by a metal oxide based electronic nose (e-nose of KAMINA-type). Linear discriminant analysis (LDA) of sensor resistivity data was performed for differentiation. Simultaneously an ion mobility spectrometer (IMS) was coupled to the emission chamber for detection of gaseous components above spice mixtures. The measured spectra show differences between the two spice mixtures and were discussed using a principal component analysis (PCA). The two multigas sensors permit discrimination between the types of spice mixtures and can indicate product adulteration. Additionally, a headspace gas analysis by gas chromatography was performed to identify the main volatile components and to prove the chemical basis for the observed differences of the multi gas sensors. KW - Spice mixtures KW - Product adulteration KW - Electronic nose KW - Ion mobility spectrometer KW - Gas chromatography KW - Multivariate data analysis PY - 2012 DO - https://doi.org/10.1016/j.foodcont.2012.01.015 SN - 0956-7135 VL - 26 IS - 1 SP - 23 EP - 27 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-25402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -