@article{BresselHassReich2013,
  author    = {Bressel, Lena and Hass, Roland and Reich, O.},
  title     = {Particle sizing in highly turbid dispersions by Photon Density Wave spectroscopy},
  series = {JOURNAL OF QUANTITATIVE SPECTROSCOPY \& RADIATIVE TRANSFER},
  volume    = {126},
  journal   = {JOURNAL OF QUANTITATIVE SPECTROSCOPY \& RADIATIVE TRANSFER},
  number    = {1},
  publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
  address   = {OXFORD},
  issn      = {0022-4073},
  doi       = {10.1016/j.jqsrt.2012.11.031},
  pages     = {122 -- 129},
  year      = {2013},
  abstract  = {Photon Density Wave (PDW) spectroscopy is presented as a fascinating technology for the independent determination of scattering (mu(s)\’ and absorption (ita) properties of highly turbid liquid dispersions. The theory is reviewed introducing new expressions for the PDW coefficients k(I) and k(Phi). Furthermore, two models for dependent scattering, namely the hard sphere model in the Percus-Yevick Approximation (HSPYA) and the Yukawa model in the Mean Spherical Approximation (YMSA), are experimentally examined. On the basis of the HSPYA particle sizing is feasible in dispersions of high ionic strength. It is furthermore shown that in dialyzed dispersions or in technical copolymers with high particle charge only the YMSA allows for correct dilution-free particle sizing. (C) 2013 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{SandmannMuenzbergBresseletal.2022,
  author    = {Sandmann, Michael and M{\"u}nzberg, Marvin and Bressel, Lena and Reich, Oliver and Hass, Roland},
  title     = {Inline monitoring of high cell density cultivation of Scenedesmus rubescens in a mesh ultra-thin layer photobioreactor by photon density wave spectroscopy},
  series = {BMC Research Notes / Biomed Central},
  volume    = {15},
  journal   = {BMC Research Notes / Biomed Central},
  number    = {1},
  publisher = {Biomed Central (London)},
  address   = {London},
  issn      = {1756-0500},
  doi       = {10.1186/s13104-022-05943-2},
  pages     = {7},
  year      = {2022},
  abstract  = {Objective Due to multiple light scattering that occurs inside and between cells, quantitative optical spectroscopy in turbid biological suspensions is still a major challenge. This includes also optical inline determination of biomass in bioprocessing. Photon Density Wave (PDW) spectroscopy, a technique based on multiple light scattering, enables the independent and absolute determination of optical key parameters of concentrated cell suspensions, which allow to determine biomass during cultivation. Results A unique reactor type, called "mesh ultra-thin layer photobioreactor" was used to create a highly concentrated algal suspension. PDW spectroscopy measurements were carried out continuously in the reactor without any need of sampling or sample preparation, over 3 weeks, and with 10-min time resolution. Conventional dry matter content and coulter counter measurements have been employed as established offline reference analysis. The PBR allowed peak cell dry weight (CDW) of 33.4 g L-1. It is shown that the reduced scattering coefficient determined by PDW spectroscopy is strongly correlated with the biomass concentration in suspension and is thus suitable for process understanding. The reactor in combination with the fiber-optical measurement approach will lead to a better process management.},
  language  = {en}
}