@incollection{AscheBoeckmannLaueetal.2000,
  author    = {Asche, Hartmut and B{\"o}ckmann, Christine and Laue, Steffen and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Lemke, Matthias and Schober, Lars and Reich, Oliver and L{\"u}ck, Erika and Sch{\"u}tte, Marc and Domsch, Horst and Makower, Alexander and Scheller, Frieder W. and St{\"o}cklein, Wolfgang and Wollenberger, Ursula and Schultze, Rainer and Hengstermann, Theo and Schael, Frank},
  title     = {Umweltforschung f{\"u}r das Land Brandenburg : Projekt Umweltanalytik / Umweltmeßtechnik / Informationssysteme},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-3862},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {176 -- 227},
  year      = {2000},
  language  = {de}
}
@misc{WernerMuenzbergHassetal.2016,
  author    = {Werner, Peter and M{\"u}nzberg, Marvin and Hass, Roland and Reich, Oliver},
  title     = {Process analytical approaches for the coil-to-globule transition of poly(N-isopropylacrylamide) in a concentrated aqueous suspension},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {944},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-43116},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431162},
  pages     = {807 -- 819},
  year      = {2016},
  abstract  = {The coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) microgel particles suspended in water has been investigated in situ as a function of heating and cooling rate with four optical process analytical technologies (PAT), sensitive to structural changes of the polymer. Photon Density Wave (PDW) spectroscopy, Focused Beam Reflectance Measurements (FBRM), turbidity measurements, and Particle Vision Microscope (PVM) measurements are found to be powerful tools for the monitoring of the temperature-dependent transition of such thermo-responsive polymers. These in-line technologies allow for monitoring of either the reduced scattering coefficient and the absorption coefficient, the chord length distribution, the reflected intensities, or the relative backscatter index via in-process imaging, respectively. Varying heating and cooling rates result in rate-dependent lower critical solution temperatures (LCST), with different impact of cooling and heating. Particularly, the data obtained by PDW spectroscopy can be used to estimate the thermodynamic transition temperature of PNIPAM for infinitesimal heating or cooling rates. In addition, an inverse hysteresis and a reversible building of micrometer-sized agglomerates are observed for the PNIPAM transition process.},
  language  = {en}
}
@misc{ReichLoehmannsroebenSchael2003,
  author    = {Reich, Oliver and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Schael, Frank},
  title     = {Optical sensing with photon density waves: investigation of model media},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13147},
  year      = {2003},
  abstract  = {Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies.},
  language  = {en}
}
@misc{LoehmannsroebenKantorKumkeetal.2005,
  author    = {L{\"o}hmannsr{\"o}ben, Hans-Gerd and Kantor, Zoltan and Kumke, Michael Uwe and Schm{\"a}lzlin, Elmar and Reich, Oliver},
  title     = {OPQS - optische Prozess- und Qualit{\"a}ts-Sensorik},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13205},
  year      = {2005},
  abstract  = {Im vorliegenden Beitrag wird an Hand dreier Beispiele der Einsatz von optischer Sensorik zur Produktcharakterisierung dargestellt, n{\"a}mlich Untersuchungen zum O2-Gehalt in Fruchts{\"a}ften, zur Isotopiesignatur von CO2 in Mineralw{\"a}ssern und zu Lichtstreueigenschaften eines Sonnenschutzmittels. Inhalt: Bestimmung von O2 mit Lumineszenzsonden Isotopenselektive Bestimmung von CO2 mit TDLAS Optische Charakterisierung stark streuender Materialien mit Photonendichtewellen},
  language  = {de}
}
@misc{MuenzbergHassKhanhetal.2016,
  author    = {M{\"u}nzberg, Marvin and Hass, Roland and Khanh, Ninh Dinh Duc and Reich, Oliver},
  title     = {Limitations of turbidity process probes and formazine as their calibration standard},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {831},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-42826},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428263},
  pages     = {12},
  year      = {2016},
  abstract  = {Turbidity measurements are frequently implemented for the monitoring of heterogeneous chemical, physical, or biotechnological processes. However, for quantitative measurements, turbidity probes need calibration, as is requested and regulated by the ISO 7027:1999. Accordingly, a formazine suspension has to be produced. Despite this regulatory demand, no scientific publication on the stability and reproducibility of this polymerization process is available. In addition, no characterization of the optical properties of this calibration material with other optical methods had been achieved so far. Thus, in this contribution, process conditions such as temperature and concentration have been systematically investigated by turbidity probe measurements and Photon Density Wave (PDW) spectroscopy, revealing an influence on the temporal formazine formation onset. In contrast, different reaction temperatures do not lead to different scattering properties for the final formazine suspensions, but give an access to the activation energy for this condensation reaction. Based on PDW spectroscopy data, the synthesis of formazine is reproducible. However, very strong influences of the ambient conditions on the measurements of the turbidity probe have been observed, limiting its applicability. The restrictions of the turbidity probe with respect to scatterer concentration are examined on the basis of formazine and polystyrene suspensions. Compared to PDW spectroscopy data, signal saturation is observed at already low reduced scattering coefficients.},
  language  = {en}
}