No abstract

A new technique is presented which allows the use of a front-end sensor head for in situ and on-line characterization of cell concentration and cell size during fermentation. An epifluorescence microscope is mounted in a port of a bioreactor viewing directly into the agitated broth. Still images from cells are generated using pulsed illumination. They are directly visualized on a monitor and used for automatic image analysis. The cell concentration and morphological information are determined by counting and evaluating the cell images with respect to their depth from focus characteristic. An in situ microscope was successfully tested during yeast fermentations and yielded results which correlated well with results from a hemocytometer. (c) 1995 John Wiley & Sons, Inc.

Natural plant fibers represent a sustainable alternative to conventional fiber reinforcement materials in cementitious materials due to their suitable mechanical properties, cost-effective availability and principle carbon neutrality. Due to its high tensile strength and stiffness as well as its worldwide distribution along with rapid growth, bamboo offers itself in particular as a plant fiber source. In experimental studies on concrete beams reinforced with plant fibers, a positive influence of the fibers on the flexural behavior was observed. However, the load-bearing effect of the fibers was limited by the poor bond, which can be attributed, among other things, to the swelling behavior of the fibers. In addition, the plant fibers degrade in the alkaline environment of many cementitious building materials. In order to improve the bond and to limit the alkalinity and to increase the durability, the use of ultra-high performance concrete (UHPC) offers itself. Since no tests have been carried out, investigations on the flexural behavior of UHPC with bamboo fibers were carried out at the Institute of Concrete Construction of Leibniz University Hannover. The test results show a significantly improved load-bearing behavior of the fibers and the enormous potential of the combination of UHPC and bamboo fibers.

No abstract

No abstract