The Bacteriology of ''clean Rooms'' Final Report

Microbial sampling in industrial clean rooms, hand contact contamination experiments, and evaluation of vertical laminar flow roo

Probabilistic Model-Based Safety Analysis

Model-based safety analysis approaches aim at finding critical failure combinations by analysis of models of the whole system (i.e. software, hardware, failure modes and environment). The advantage of these methods compared to traditional approaches is that the analysis of the whole system gives more precise results. Only few model-based approaches have been applied to answer quantitative questions in safety analysis, often limited to analysis of specific failure propagation models, limited types of failure modes or without system dynamics and behavior, as direct quantitative analysis is uses large amounts of computing resources. New achievements in the domain of (probabilistic) model-checking now allow for overcoming this problem. This paper shows how functional models based on synchronous parallel semantics, which can be used for system design, implementation and qualitative safety analysis, can be directly re-used for (model-based) quantitative safety analysis. Accurate modeling of different types of probabilistic failure occurrence is shown as well as accurate interpretation of the results of the analysis. This allows for reliable and expressive assessment of the safety of a system in early design stages

[Photograph 2012.201.B0343.0045]

Photograph used for a newspaper owned by the Oklahoma Publishing Company. Caption: "Emmett Knight, director of the Cherokee arts and crafts project, shows some bowls and a horse carved by David Russell.

Complications in the Systematic Study of Photochemical Mechanisms

The rate constants for energy transfer have been measured by flash spectroscopic techniques. These results show that 1,3-cyclohexadiene undergoes a nonvertical transition when low energy sensitizers are used. The quantum yields for the high energy sensitized dimerization of 1,3-cyclohexadiene are consistant with the simple mechanism proposed. The use of 1,2-benzanthracene, a low energy sensitizer, to sensitize the dimerization of 1,3-cyclohexadiene has been studied in detail. The results show that in addition to energy transfer from donor to acceptor, other steps such as reversible energy transfer, adduct formation, singlet quenching of aromatic hydrocarbons by dienes and sensitizer-sensitizer interactions are important.</p