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Instantaneous images of the smoke released to the unstable surface boundary layer from a chimney are simulated numerically.The characteristic patterns of instantaneous images are formed by introducing spatial correlation of velocity. Trajectories correlated spatially are obtained by use of random variables correlated spatially in a Markov chain equation. In order to generate the field of random variables correlated spatially, a random number is given for each region divided by a length corresponding to the scale of turbulence.Empirical profiles of the mean and fluctuation of wind velocity are used in the Markov chain. The scale of turbulence is estimated from these profiles. Numerical simulations of the diffusion released from a source of 60 m height were carried out. Under certain atmospheric conditions, some samples of image are formed. The results with irregular patterns seem to be realistic. The spatial correlation of velocity was detected from the results of simulation, which is smaller than that of the given random variable.

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In application of micropumps to new fields in chemistry, biology, medical science and others, smaller sizes are supposed to be important rather than higher pump performance. In this study, considering from such a view point, micropumps using rotational and reciprocating motions of magnetic material balls were proposed and studied experimentally. The pump performance, i.e. the relation between flow rate and pump head are measured from liquid level changes in two containers connected to the inlet and outlet of the micropump. For the rotational motion micropump, while the maximum flow rate obtained, ~2 mL/min, is large enough as a micropump, the maximum pump head achieved, ~15 mm, is small even for a micropump. It is desirable to increase the pump head furthermore for this micropump. For the reciprocating motion micropump, the maximum flow rate obtained and the maximum pump head achieved are ~7.5 mL/min and ~625 mm, respectively. These values of the pump performance are sufficient as a micropump. Both the micropumps can be incorporated into microfluidic devices (tips) and can pump arbitrary kind of liquid.