@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{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} } @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} } @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} } @inproceedings{KhaledBruhnsReichlingetal., author = {Khaled, W. and Bruhns, Otto T. and Reichling, S. and B{\"o}se, Holger and Baumann, Michael and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and Klein, Dagmar and Freimuth, Herbert and Ermert, Helmut}, title = {A haptic sensor-actuator-system based on ultrasound elastography and electrorheological fluids for virtual reality applications in medicine}, series = {CARS 2003 : computer assisted radiology and surgery ; proceedings of the 17th International Congress and Exhibition London, June 25 - 28, 2003}, booktitle = {CARS 2003 : computer assisted radiology and surgery ; proceedings of the 17th International Congress and Exhibition London, June 25 - 28, 2003}, publisher = {Elsevier}, address = {Amsterdam}, pages = {1354}, abstract = {Mechanical properties of biological tissue represent important diagnostic information and are of histological relevance (hard lesions, "nodes" in organs: tumors; calcifications in vessels: arteriosclerosis). The problem is, that such information is usually obtained by digital palpation only, which is limited with respect to sensitivity. It requires intuitive assessment and does not allow quantitative documentation. A suitable sensor is required for quantitative detection of mechanical tissue properties. On the other hand, there is also some need for a realistic mechanical display of those tissue properties. Suitable actuator arrays with high spatial resolution and real-time capabilities are required operating in a haptic sensor actuator system with different applications. The sensor system uses real time ultrasonic elastography whereas the tactile actuator is based on electrorheological fluids. Due to their small size the actuator array elements have to be manufactured by micro-mechanical production methods. In order to supply the actuator elements with individual high voltages a sophisticated switching and control concept have been designed. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching, space and telecommunication.}, language = {en} } @article{BeckerRaikherStolbovetal., author = {Becker, Tatiana I. and Raikher, Yuriy L. and Stolbov, Oleg V. and B{\"o}hm, Valter and Zimmermann, Klaus}, title = {Magnetoactive elastomers for magnetically tunable vibrating sensor systems}, series = {Physical Sciences Reviews}, volume = {7}, journal = {Physical Sciences Reviews}, number = {10}, publisher = {de Gruyter}, issn = {2365-659X}, doi = {10.1515/psr-2019-0125}, pages = {1 -- 28}, abstract = {Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled "configuration" can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes.}, language = {de} } @misc{PremSindersbergerMonkman, author = {Prem, Nina and Sindersberger, Dirk and Monkman, Gareth J.}, title = {Spectroscopic Analysis of Magneto-Active Polymers (MAP) - Poster}, series = {DFG-Tagung, Benediktbeuern, September 2017}, journal = {DFG-Tagung, Benediktbeuern, September 2017}, language = {en} } @misc{HeinrichKetterl, author = {Heinrich, Tobias and Ketterl, Hermann}, title = {AI to quantify biological diversity}, series = {LANDSUPPORT Final Conference and the Save Our Soils Workshop, 27 -28 APRIL 2022, Portici, Italy}, journal = {LANDSUPPORT Final Conference and the Save Our Soils Workshop, 27 -28 APRIL 2022, Portici, Italy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-50080}, abstract = {The primary consumers of plant exudates - in exact fungi and bacteria, are representative for the soil succession level from bare soil, which is bacterial dominant to old growth forest constitute by fungal dominance. In a specified level of soil succession, a special kind of plant family benefits on the Fungal to Bacteria Ratio. The ability to determine this ratio in situ without complex chemical applications is part of the project Electronical Laboratory for Intelligent Soil Examination (ELISE). Several mechanical and optical tests on soil samples are covered within this Project. To analyze the fungal to bacteria ratio, samples are prepared automatically - in a defined and reproductive procedure - to generate slides for shadowing microscopy. The samples are observed by a camera, which is attached to a transmitted light microscope. The automatic analysis, done with computer vision algorithms, aims to quantify bacterial and fungal biomass in the actual sample view. Moreover, the algorithm can classify organisms according to their color and shape. To get a processable picture, several images from different focal levels must be taken through the sample thickness. Parts of each image, are in focus at the actual layer, are merged to a whole depth of field picture, by focus stacking. This produced picture is used to classify, locate and quantify - in first step filamentous organisms e.g. fungal by image sematic segmentation. The result represents an image sized mask, which indicates the class of fungi with class equivalate values at the pixel positions - covered by the organism. This information is used to calculate the fungal mass per gram soil. To quantify the bacterial biomass two approaches are implemented. For low density of bacterial existence, the individual bacteria is counted for a part of the field of view by an image detection algorithm to be extrapolate afterwards to the mass per gram soil. For high density of bacterial occurrence, specified regions of interest with only bacteria present are chosen. An image classification which has been pretrained by pictures of bacterial density patterns - previously determent by making the sample countable due to preforming sample dilutions, is done. The second option for high density bacterial count is, to automatically preform dilutions until the image detection is confidently countable. To ensure a usable confidence score a statistical approach of many fields of view is taken.}, language = {en} } @misc{KetterlHeinrich, author = {Ketterl, Hermann and Heinrich, Tobias}, title = {Vivid tool for comprehensive biological soil analysis}, series = {LANDSUPPORT Final Conference and the Save Our Soils Workshop, 27 -28 APRIL 2022, Portici, Italy}, journal = {LANDSUPPORT Final Conference and the Save Our Soils Workshop, 27 -28 APRIL 2022, Portici, Italy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-50078}, abstract = {The sample preparation for shadowing microscopy, to examinate biological soil properties, is time consuming, manual work. The outcome depends on subjective skills of the operator, furthermore the results are mostly not quantitative. The database on biological soil properties is mostly not sufficient for an integrated modelling on an multidisciplinary scale. This project combines three progressive approaches to develop a tool that is easy to use and gives in situ results that can be used for many purposes.}, language = {en} }