Chitosan, a polycationic polymer and waste product from the sea food processing industry, is an abundant natural resource that has, as yet, not been fully utilized. Advantages of this polymer include availability, low cost, high biocompatibility, biodegradability and ease of chemical modification. In this paper, the physicochemical properties of chitosan, as well as its numerous applications, are reviewed with particular emphasis on its use in water treat ment, pharmaceutics, agriculture and membrane formation.

No abstract

Multiple‐jet cold‐model burners aerodynamically simulating a class of industrial burners were studied. The fields of mean velocity and velocity fluctuation intensity were measured with Pitot probes. The validity of an effective source diameter as a characteristic length scale is demonstrated. Beyond the nearfield, the flows are virtually the same, and similar to a round jet from a single source. In the nearfield, individual structures peculiar to each burner are observed. The results support the mathematical modelling, for some types of simulations, of flows from complex burners as point‐source jets, affording a substantial simplification of the treatment.

Becker, Hottel and Williams have employed marker nephelometry to determine many characteristics of the nozzle fluid concentration field of the round turbulent free jet: the mean concentration, concentration fluctuations, intermittency factor, spectrum and correlation functions, and integral scales. In the present work a much larger jet nozzle was employed, 7.14 cm throat diameter compared to 0.635 cm in the reference, and the Reynolds number was correspondingly greater, around 270,000 compared to 54,000. The results support Becker et al's findings and extend the range of the data. In particular, the spectrum of the concentration fluctuations has been measured into the viscous convective subrange where a (‐1) power mode dependency on wave number is indicated, as expected for the slow diffusing smoke marker. Other new measurements include the skewness, kurtosis, and probability density function of the concentration fluctuations.

No abstract