@inproceedings{WohlschlaegerVersenLanghals2019, author = {Wohlschl{\"a}ger, Maximilian and Versen, Martin and Langhals, H.}, title = {A method for sorting of plastics with an apparatus specific quantum efficiency approach}, series = {2019 IEEE Sensors Applications Symposium (SAS)}, booktitle = {2019 IEEE Sensors Applications Symposium (SAS)}, year = {2019}, abstract = {Today, the automatic separation of polymers from each other in an industrial scale is an unsolved problem. In laboratory environments, two methods are known whereby plastic is sorted either by color or by fluorescence decay time measurements that require fast synchronization and thus expensive equipment. A simple and pragmatic process is proposed to separate plastics from each other: all fluorescent photons are counted in relation to the absorbed photons. A theoretical model and an experimental setup are built in order to determine an apparatus specific quantum efficiency.}, language = {en} } @inproceedings{LeiterWohlschlaegerAueretal.2021, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Auer, Veronika and Versen, Martin and Laforsch, Christian}, title = {A Novel Approach to Identify Wood Species Optically using Fluorescence Lifetime Imaging Microscopy}, series = {SMSI 2021 Conference - Sensor and Measurement Science International}, booktitle = {SMSI 2021 Conference - Sensor and Measurement Science International}, pages = {169 -- 170}, year = {2021}, abstract = {This contribution presents the results obtained with fluorescence lifetime imaging microscopy (FLIM)within the optical identification and differentiation of the four wood species walnut, beech, spruce, and maple. The experimental setup as well as the evaluation algorithm, with which the experiments were carried out, is explained briefly.}, language = {en} } @inproceedings{WohlschlaegerVersenLaforsch2022, author = {Wohlschlaeger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {A novel approach to optically detect microplastic in an environmental matrix with Rapid-FLIM}, series = {Sensors and Measuring Systems; 21th ITG/GMA-Symposium}, booktitle = {Sensors and Measuring Systems; 21th ITG/GMA-Symposium}, pages = {1 -- 6}, year = {2022}, language = {en} } @inproceedings{WohlschlaegerHolstVersen2020, author = {Wohlschl{\"a}ger, Maximilian and Holst, Gerhard and Versen, Martin}, title = {A novel approach to optically distinguish plastics based on fluorescence lifetime measurements}, series = {2020 IEEE Sensors Applications Symposium (SAS)}, booktitle = {2020 IEEE Sensors Applications Symposium (SAS)}, doi = {10.1109/SAS48726.2020.9220084}, pages = {1 -- 6}, year = {2020}, abstract = {In medical and biological research, fluorescence lifetime measurements and fluorescence lifetime imaging is already a part of the standardized analysis procedures. As first investigations have shown, polymers can be identified using fluorescence lifetime imaging and an evaluation algorithm. Thus, this contribution pursues a novel approach for the direct differentiation of four polymers with fluorescence lifetime imaging. Therefore, the evaluation algorithm is extended to compare several fluorescence lifetime images to prove that a distinction is possible.}, language = {en} } @inproceedings{WohlschlaegerHolstVersen2020, author = {Wohlschl{\"a}ger, Maximilian and Holst, G. and Versen, Martin}, title = {A novel approach to optically distinguish plastics based on fluorescence lifetime measurements}, series = {2020 IEEE Sensors Applications Symposium (SAS), Kuala Lumpur, Malaysia}, booktitle = {2020 IEEE Sensors Applications Symposium (SAS), Kuala Lumpur, Malaysia}, pages = {1 -- 6}, year = {2020}, language = {en} } @article{WohlschlaegerVersenLoederetal.2024, author = {Wohlschl{\"a}ger, Maximilian and Versen, Martin and L{\"o}der, Martin G. J. and Laforsch, Christian}, title = {A promising method for fast identification of microplastic particles in environmental samples: A pilot study using fluorescence lifetime imaging microscopy}, series = {Heliyon}, volume = {10}, journal = {Heliyon}, number = {3}, doi = {10.1016/j.heliyon.2024.e25133}, year = {2024}, abstract = {Microplastic pollution of the environment has been extensively studied, with recent studies focusing on the prevalence of microplastics in the environment and their effects on various organisms. Identification methods that simplify the extraction and analysis process to the point where the extraction can be omitted are being investigated, thus enabling the direct identification of microplastic particles. Currently, microplastic samples from environmental matrices can only be identified using time-consuming extraction, sample processing, and analytical methods. Various spectroscopic methods are currently employed, such as micro Fourier-transform infrared, attenuated total reflectance, and micro Raman spectroscopy. However, microplastics in environmental matrices cannot be directly identified using these spectroscopic methods. Investigations using frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) to identify and differentiate plastics from environmental materials have yielded promising results for directly identifying microplastics in an environmental matrix. Herein, two artificially prepared environmental matrices that included natural soil, grass, wood, and high-density polyethylene were investigated using FD-FLIM. Our first results showed that we successfully identified one plastic type in the two artificially prepared matrices using FD-FLIM. However, further research must be conducted to improve the FD-FLIM method and explore its limitations for directly identifying microplastics in environmental samples.}, language = {en} } @article{VersenErnstGulati2017, author = {Versen, Martin and Ernst, W. and Gulati, P.}, title = {A row hammer pattern analysis of DDR2 SDRAM}, series = {Microelectronics Reliability}, volume = {76-77}, journal = {Microelectronics Reliability}, pages = {64 -- 67}, year = {2017}, abstract = {A DDR2 SDRAM test setup implemented on the Griffin III ATE test system from HILEVEL Technologies is used to analyse the row hammer bug. Row hammer pattern experiments are compared to standard retention tests. The analysis confirms that the row hammer effect is caused by a charge excitation process depending on the number of stress activation cycles. The stress has to occur in the local neighborhood of the cells under test. Shallow impurity levels support the responsible charge carrier transport process in the used DDR2 SDRAM technology}, language = {en} } @article{LeiterWohlschlaegerVersenetal.2022, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Versen, Martin and Laforsch, Christian}, title = {An algorithmic method for the identification of wood species and the classification of post-consumer wood using fluorescence lifetime imaging microscopy}, series = {Journal of Sensors and Sensor Systems}, volume = {11}, journal = {Journal of Sensors and Sensor Systems}, number = {1}, doi = {10.5194/jsss-11-129-2022}, pages = {129 -- 136}, year = {2022}, abstract = {In this contribution the frequency domain fluorescence lifetime imaging microscopy (FD-FLIM) technique is evaluated for post-consumer wood sorting. The fluorescence characteristics of several wood samples were determined, whereby two excitation wavelengths (405 and 488 nm) were used. The measured data were processed using algorithmic methods to identify the wood species and post-consumer wood category. With the excitation wavelength of 405 nm, 16 out of 19 samples could be correctly assigned to the corresponding post-consumer wood category by means of the fluorescence lifetimes. Thus, the experimental results revealed the high potential of the FD-FLIM technique for automated post-consumer wood sorting.}, language = {en} } @inproceedings{LeiterWohlschlaegerAueretal.2021, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Auer, Veronika and Versen, Martin and Laforsch, Christian}, title = {An algorithmic method to identify multiple wood species in a single image by their specific fluorescence lifetimes}, series = {OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP) (2021), paper CF2B.3}, booktitle = {OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP) (2021), paper CF2B.3}, doi = {10.1364/COSI.2021.CF2B.3}, pages = {CF2B.3}, year = {2021}, abstract = {Fluorescence lifetime imaging microscopy (FLIM) combined with an image processing algorithm is successfully used for the optical identification and areal separation of three wood species of maple, larch and nut in a single taken image.}, language = {en} } @inproceedings{LeiterWohlschlaegerAueretal.2021, author = {Leiter, Nina and Wohlschl{\"a}ger, Maximilian and Auer, Veronika and Versen, Martin and Laforsch, Christian}, title = {An algorithmic method to identify multiple wood species in a single image by their specific fluorescence lifetimes}, series = {OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP)}, booktitle = {OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP)}, doi = {10.1364/COSI.2021.CF2B.3}, pages = {CF2B.3}, year = {2021}, abstract = {Fluorescence lifetime imaging microscopy (FLIM) combined with an image processing algorithm is successfully used for the optical identification and areal separation of three wood species of maple, larch and nut in a single taken image.}, language = {en} }