@article{VahidpourOberlaenderSchoening2018,
  author    = {Vahidpour, Farnoosh and Oberl{\"a}nder, Jan and Sch{\"o}ning, Michael Josef},
  title     = {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},
  series = {Phys. Status Solidi A},
  volume    = {215},
  journal   = {Phys. Status Solidi A},
  number    = {15},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  doi       = {10.1002/pssa.201800044},
  pages     = {Artikel 1800044},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{JildehKirchnerOberlaenderetal.2020,
  author    = {Jildeh, Zaid B. and Kirchner, Patrick and Oberl{\"a}nder, Jan and Vahidpour, Farnoosh and Wagner, Patrick H. and Sch{\"o}ning, Michael Josef},
  title     = {Development of a package-sterilization process for aseptic filling machines: A numerical approach and validation for surface treatment with hydrogen peroxide},
  series = {Sensor and Actuators A: Physical},
  volume    = {303},
  journal   = {Sensor and Actuators A: Physical},
  number    = {111691},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0924-4247},
  doi       = {10.1016/j.sna.2019.111691},
  year      = {2020},
  abstract  = {Within the present work a sterilization process by a heated gas mixture that contains hydrogen peroxide (H₂O₂) is validated by experiments and numerical modeling techniques. The operational parameters that affect the sterilization efficacy are described alongside the two modes of sterilization: gaseous and condensed H₂O₂. Measurements with a previously developed H₂O₂ gas sensor are carried out to validate the applied H₂O₂ gas concentration during sterilization. We performed microbiological tests at different H₂O₂ gas concentrations by applying an end-point method to carrier strips, which contain different inoculation loads of Geobacillus stearothermophilus spores. The analysis of the sterilization process of a pharmaceutical glass vial is performed by numerical modeling. The numerical model combines heat- and advection-diffusion mass transfer with vapor-pressure equations to predict the location of condensate formation and the concentration of H₂O₂ at the packaging surfaces by changing the gas temperature. For a sterilization process of 0.7 s, a H₂O₂ gas concentration above 4\% v/v is required to reach a log-count reduction above six. The numerical results showed the location of H₂O₂ condensate formation, which decreases with increasing sterilant-gas temperature. The model can be transferred to different gas nozzle- and packaging geometries to assure the absence of H₂O₂ residues.},
  language  = {en}
}