TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Artificial Neural Networks and pattern recognition for air-water flow velocity estimation using a single-tip optical fibre probe JF - Journal of Hydro-environment Research Y1 - 2017 U6 - http://dx.doi.org/10.1016/j.jher.2017.08.004 SN - 1570-6443 VL - 19 IS - 3 SP - 150 EP - 159 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Valero, Daniel A1 - Bung, Daniel B. T1 - Vectrino profiler spatial filtering for shear flows based on the mean velocity gradient equation JF - Journal of Hydraulic Engineering N2 - A new methodology is proposed to spatially filter acoustic Doppler velocimetry data from a Vectrino profiler based on the differential mean velocity equation. Lower and upper bounds are formulated in terms of physically based flow constraints. Practical implementation is discussed, and its application is tested against data gathered from an open-channel flow over a stepped macroroughness surface. The method has proven to detect outliers occurring all over the distance range sampled by the Vectrino profiler and has shown to remain applicable out of the region of validity of the velocity gradient equation. Finally, a statistical analysis suggests that physically obtained bounds are asymptotically representative. Y1 - 2018 U6 - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001485 SN - 0733-9429 N1 - Article number 04018037 VL - 144 IS - 7 PB - ASCE CY - Reston, Va. ER - TY - JOUR A1 - Valero, D. A1 - Bung, Daniel B. A1 - Crookston, B. M. T1 - Closure to “Energy Dissipation of a Type III Basin under Design and Adverse Conditions for Stepped and Smooth Spillways” JF - Journal of Hydraulic Engineering Y1 - 2019 U6 - http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0001669 VL - 146 IS - 2 PB - ASCE CY - Reston, Va. ER - TY - JOUR A1 - Vahidpour, Farnoosh A1 - Oberländer, Jan A1 - Schöning, Michael Josef T1 - Flexible Calorimetric Gas Sensors for Detection of a Broad Concentration Range of Gaseous Hydrogen Peroxide: A Step Forward to Online Monitoring of Food-Package Sterilization Processes JF - Phys. Status Solidi A N2 - In this study, flexible calorimetric gas sensors are developed for specificdetection of gaseous hydrogen peroxide (H₂O₂) over a wide concentrationrange, which is used in sterilization processes for aseptic packaging industry.The flexibility of these sensors is an advantage for identifying the chemical components of the sterilant on the corners of the food boxes, so-called “coldspots”, as critical locations in aseptic packaging, which are of great importance. These sensors are fabricated on flexible polyimide films by means of thin-film technique. Thin layers of titanium and platinum have been deposited on polyimide to define the conductive structures of the sensors. To detect the high-temperature evaporated H₂O₂, a differential temperature set-up is proposed. The sensors are evaluated in a laboratory-scaled sterilizationsystem to simulate the sterilization process. The concentration range of the evaporated H₂O₂ from 0 to 7.7% v/v was defined and the sensors have successfully detected high as well as low H₂O₂ concentrations with a sensitivity of 5.04 °C/% v/v. The characterizations of the sensors confirm their precise fabrication, high sensitivity and the novelty of low H₂O₂ concentration detections for future inline monitoring of food-package sterilization. Y1 - 2018 U6 - http://dx.doi.org/10.1002/pssa.201800044 VL - 215 IS - 15 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Vahidpour, Farnoosh A1 - Guthman, Eric A1 - Arreola, Julia A1 - Alghazali, Yousef H. M. A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Assessment of Various Process Parameters for Optimized Sterilization Conditions Using a Multi-Sensing Platform JF - Foods N2 - In this study, an online multi-sensing platform was engineered to simultaneously evaluate various process parameters of food package sterilization using gaseous hydrogen peroxide (H₂O₂). The platform enabled the validation of critical aseptic parameters. In parallel, one series of microbiological count reduction tests was performed using highly resistant spores of B. atrophaeus DSM 675 to act as the reference method for sterility validation. By means of the multi-sensing platform together with microbiological tests, we examined sterilization process parameters to define the most effective conditions with regards to the highest spore kill rate necessary for aseptic packaging. As these parameters are mutually associated, a correlation between different factors was elaborated. The resulting correlation indicated the need for specific conditions regarding the applied H₂O₂ gas temperature, the gas flow and concentration, the relative humidity and the exposure time. Finally, the novel multi-sensing platform together with the mobile electronic readout setup allowed for the online and on-site monitoring of the sterilization process, selecting the best conditions for sterility and, at the same time, reducing the use of the time-consuming and costly microbiological tests that are currently used in the food package industry. KW - spore kill rate KW - sterility KW - aseptic parameters KW - multi-sensing platform KW - gaseous hydrogen peroxide Y1 - 2022 U6 - http://dx.doi.org/10.3390/foods11050660 SN - 2304-8158 N1 - This article belongs to the Special Issue "Sensors and Biosensors Application for Food Industries" VL - 11 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Vahidpour, Farnoosh A1 - Alghazali, Yousef A1 - Akca, Sevilay A1 - Hommes, Gregor A1 - Schöning, Michael Josef T1 - An Enzyme-Based Interdigitated Electrode-Type Biosensor for Detecting Low Concentrations of H₂O₂ Vapor/Aerosol JF - Chemosensors N2 - This work introduces a novel method for the detection of H₂O₂ vapor/aerosol of low concentrations, which is mainly applied in the sterilization of equipment in medical industry. Interdigitated electrode (IDE) structures have been fabricated by means of microfabrication techniques. A differential setup of IDEs was prepared, containing an active sensor element (active IDE) and a passive sensor element (passive IDE), where the former was immobilized with an enzymatic membrane of horseradish peroxidase that is selective towards H₂O₂. Changes in the IDEs’ capacitance values (active sensor element versus passive sensor element) under H₂O₂ vapor/aerosol atmosphere proved the detection in the concentration range up to 630 ppm with a fast response time (<60 s). The influence of relative humidity was also tested with regard to the sensor signal, showing no cross-sensitivity. The repeatability assessment of the IDE biosensors confirmed their stable capacitive signal in eight subsequent cycles of exposure to H₂O₂ vapor/aerosol. Room-temperature detection of H₂O₂ vapor/aerosol with such miniaturized biosensors will allow a future three-dimensional, flexible mapping of aseptic chambers and help to evaluate sterilization assurance in medical industry. Y1 - 2022 U6 - http://dx.doi.org/10.3390/chemosensors10060202 SN - 2227-9040 N1 - This article belongs to the Special Issue "Bioinspired Chemical Sensors and Micro-Nano Devices" VL - 10 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Uysal, Karya A1 - Firat, Ipek Serat A1 - Creutz, Till A1 - Aydin, Inci Cansu A1 - Artmann, Gerhard A1 - Teusch, Nicole A1 - Temiz Artmann, Aysegül T1 - A novel in vitro wound healing assay using free-standing, ultra-thin PDMS membranes JF - membranes N2 - Advances in polymer science have significantly increased polymer applications in life sciences. We report the use of free-standing, ultra-thin polydimethylsiloxane (PDMS) membranes, called CellDrum, as cell culture substrates for an in vitro wound model. Dermal fibroblast monolayers from 28- and 88-year-old donors were cultured on CellDrums. By using stainless steel balls, circular cell-free areas were created in the cell layer (wounding). Sinusoidal strain of 1 Hz, 5% strain, was applied to membranes for 30 min in 4 sessions. The gap circumference and closure rate of un-stretched samples (controls) and stretched samples were monitored over 4 days to investigate the effects of donor age and mechanical strain on wound closure. A significant decrease in gap circumference and an increase in gap closure rate were observed in trained samples from younger donors and control samples from older donors. In contrast, a significant decrease in gap closure rate and an increase in wound circumference were observed in the trained samples from older donors. Through these results, we propose the model of a cell monolayer on stretchable CellDrums as a practical tool for wound healing research. The combination of biomechanical cell loading in conjunction with analyses such as gene/protein expression seems promising beyond the scope published here. Y1 - 2022 U6 - http://dx.doi.org/10.3390/membranes13010022 N1 - This article belongs to the Special Issue "Latest Scientific Discoveries in Polymer Membranes" VL - 2023 IS - 13(1) PB - MDPI CY - Basel ER - TY - JOUR A1 - Uysal, Karya A1 - Creutz, Till A1 - Firat, Ipek Seda A1 - Artmann, Gerhard A1 - Teusch, Nicole A1 - Temiz Artmann, Aysegül T1 - Bio-functionalized ultra-thin, large-area and waterproof silicone membranes for biomechanical cellular loading and compliance experiments JF - Polymers N2 - Biocompatibility, flexibility and durability make polydimethylsiloxane (PDMS) membranes top candidates in biomedical applications. CellDrum technology uses large area, <10 µm thin membranes as mechanical stress sensors of thin cell layers. For this to be successful, the properties (thickness, temperature, dust, wrinkles, etc.) must be precisely controlled. The following parameters of membrane fabrication by means of the Floating-on-Water (FoW) method were investigated: (1) PDMS volume, (2) ambient temperature, (3) membrane deflection and (4) membrane mechanical compliance. Significant differences were found between all PDMS volumes and thicknesses tested (p < 0.01). They also differed from the calculated values. At room temperatures between 22 and 26 °C, significant differences in average thickness values were found, as well as a continuous decrease in thicknesses within a 4 °C temperature elevation. No correlation was found between the membrane thickness groups (between 3–4 µm) in terms of deflection and compliance. We successfully present a fabrication method for thin bio-functionalized membranes in conjunction with a four-step quality management system. The results highlight the importance of tight regulation of production parameters through quality control. The use of membranes described here could also become the basis for material testing on thin, viscous layers such as polymers, dyes and adhesives, which goes far beyond biological applications. Y1 - 2022 SN - 2073-4360 VL - 14 IS - 11 SP - 2213 PB - MDPI CY - Basel ER - TY - CHAP A1 - Usai, Pierpaolo A1 - Corucci, Alessandro A1 - Gligorevic, Snjezana A1 - Monorchio, Agostino T1 - Estimation of airport surface propagation channel: ray tracing model and measurements T2 - Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP) : 11 - 15 April 2011, Rome, Italy Y1 - 2011 SN - 978-1-4577-0250-1 SP - 1634 EP - 1638 ER - TY - JOUR A1 - Ungermanns, C. A1 - Ahe, M. v. d. A1 - Carius, Reinhard A1 - Förster, Arnold T1 - Optimization of III/V binary growth with RHEED in MOMBE / C. Ungermanns ; M. v. d. Ahe ; R. Carius ; A. Förster ... JF - Fresenius' Journal of Analytical Chemistry. 358 (1997), H. 1-2 Y1 - 1997 SN - 0937-0633 N1 - ISSN der E-Ausg.: 1432-1130 SP - 101 EP - 104 ER -