Das Aequivalentgewicht des Thalliums

Ohne Zusammenfassung     

Experimental study of jet structure and pressurisation upon liquid nitrogen injection into water

The rapid phase change and heat transfer obtained by direct contact heat exchange between a cryogen and water can generate high rates of pressurisation, which is of interest to a number of applications. A visualization study of liquid nitrogen injection into water is conducted in this work, with synchronized pressure and temperature measurement, to obtain insight into this complex phenomenon. High speed imaging reveals a four-stage evolution of liquid nitrogen jet structure upon injection into water, with a thick vapour blanket forming around a liquid nitrogen core and break-up brought on predominantly through impact with the vessel wall. Maximum pressurisation rate occurs in the third stage of injection due to a combination of heat and mass transfer. Pressurisation rates in excess of 350 bar/s are recorded and found to vary proportionally with injection pressure. The scenario of gaseous nitrogen injection is also investigated, and compared with liquid nitrogen injection. A clear advantage of liquid nitrogen injection is elucidated from the point of heat transfer and pressurisation, and implications for use in a cryogenic engine are discussed.     

Simulation in 1981

This paper considers the position of simulation modelling techniques in 1980 and reviews different developments that contribute to the current position.     

Cellular Simulation

Cellular simulation, a method of organizing simulation models to improve experimental efficiency, is described and shown to have the further advantages of reconciling the event based approach with the activity approach to simulation modelling and to have implication for modelling large systems.     

Generators,Generic Models and Methodology

A brief, personal view of methodological aspects of the design of computer programs appropriate for practical OR projects, with particular reference to simulation projects.     

Oxyde des Thalliums

Analytical and Bioanalytical Chemistry -     

Replacement Strategies

Components of a system function for a time and then fail. A central problem is to decide whether a strategy of scheduled replacement is preferable to the running of all components until failure. This is considered by comparing some simple strategies for component replacement. Considerations from probability theory and renewal theory are used to obtain expressions for the average cost of replacements per unit time for each strategy. After obtaining some general conditions for one strategy to be preferable to another, a detailed comparison is made when the interfailure times are independent samples from a gamma distribution.