Measurement of bubble size distribution in fermentors
SummaryThe “photoelectric probe method” for measuring bubble size distributions was adapted for application in turbid liquids. It can now be used for investigations of the influence of hydrodynamics and liquid phase properties on bubble formation, dispersion, and coalescence in submersed fermentation systems. With cultures of Candida utilis, cell concentrations showed little effect on bubble size and gas-liquid interface.
Blasengrößenverteilung in technischen Begasungsapparaten
Zur Berechnung der Austauschprozesse in Gas/Flussigkeits-Gemischen ist die Kenntnis der Phasengrenzflache erforderlich, die sich uber die Blasengrosenverteilung bestimmen last. Es wurde daher ein Mesverfahren zur Bestimmung der Blasengrosenverteilung eines beliebig erzeugten Gas/Flussigkeits-Gemisches entwickelt. Die Blasen werden uber einen Trichter in eine Kapillare geleitet und dort mit Hilfe einer photoelektrischen Sonde ausgemessen. Die Verteilungskurven wurden fur verschiedene technische Begasungsapparate ermittelt und uber diese Kurven auch der Einflus mehrerer Versuchsgrosen wie Gaszerteiler, Apparatetyp usw., wobei zur Beurteilung Mittelwert und Breite der Verteilung herangezogen wurden.
Preparation and performance evaluation of swine manure bio-oil modified rubber asphalt binder
Abstract In order to study the effect of the preparation process of swine manure bio-oil modified rubber asphalt binder on the rheological properties of the binder, the matrix asphalt and asphalt rubber were used as the control group, and swine manure bio-oil modified rubber asphalt binders were obtained by three preparation processes. Then the rheological properties of five binders were evaluated by rotational viscosity, DSR, MSCR and BBR tests. The results show that the addition of swine manure bio-oil to asphalt rubber is beneficial to the workability, but cause negative effect on its high temperature performance, fatigue performance and low temperature crack resistance. The preparation method of premixing bio-oil and rubber powder can reduce the degradation of high-temperature performance of asphalt rubber caused by addition of swine manure bio-oil to a certain extent. The fatigue properties of the three bio-binders are close, and the critical temperature is less than 25 °C. The process of premixing bio-oil and rubber powder will increase the creep stiffness and reduce the low-temperature performance. However, the low-temperature performance of the binder obtained by this process is still better than that of the matrix asphalt and can meet the requirements of use. Therefore, it is recommended to use the preparation process of premixing bio-oil and rubber powder to prepare swine manure bio-oil modified asphalt rubber.