A next generation, pilot-scale continuous sterilization system for fermentation media

A new continuous sterilization system was designed, constructed, started up, and qualified for media sterilization for secondary metabolite cultivations, bioconversions, and enzyme production. An existing Honeywell Total Distributed Control 3000-based control system was extended using redundant High performance Process Manager controllers for 98 I/O (input/output) points. This new equipment was retrofitted into an industrial research fermentation pilot plant, designed and constructed in the early 1980s. Design strategies of this new continuous sterilizer system and the expanded control system are described and compared with the literature (including dairy and bio-waste inactivation applications) and the weaknesses of the prior installation for expected effectiveness. In addition, the reasoning behind selection of some of these improved features has been incorporated. Examples of enhancements adopted include sanitary heat exchanger (HEX) design, incorporation of a “flash” cooling HEX, on-line calculation of F(o) and R(o), and use of field I/O modules located near the vessel to permit low-cost addition of new instrumentation. Sterilizer performance also was characterized over the expected range of operating conditions. Differences between design and observed temperature, pressure, and other profiles were quantified and investigated

Estimation of α-particle induced hot spot size in Nb film using Abrikosov vortices

A new experimental method for estimation of α-particle induced hot spot size in Nb films is proposed. The method is based on the jump-like motion of Abrikosov vortices induced by the impact of a single α-particle (241Am 5.5 MeV) on a superconducting film. Preliminary experiments were carried out on a high quality “small” Nb−AlOx−Nb Josephson tunnel junction with circular geometry and area 2500 μm2 (length smaller than λj) at T=4.2 K. A preliminary value ofd *=2.5 μm is obtained for the dimension of the hot spot region