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UDC 628.22
Sapoukhin А. А., Kurochkina V. A.
On the calculation of hydraulic radius value
Summary
The effect of the flow cross-sectional shape on the hydraulic resistance through the hydraulic radius – the ratio of the cross- (or hydraulic) flow section to its wetted perimeter is considered. With the help of the given parameter the entire variety of the flow cross sectional shapes is limited to two types: for pressure flows – circular, axially symmetric shape; for gravity flows – rectangular, very wide shape. The refined mathematical model of the correlation between the hydraulic radius and hydraulic flow parameters as well as the relationship for determining hydraulic radius, relationship parameter values for the most frequently occurring interlocking canals is presented.
Key words
hydraulic radius , hydraulic resistance , shear stress , cross-sectional shape , flow geometry
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UDC 504.054
Kofman V. Ya.
«New pollutants» in aquatic environment. Drugs, ultraviolet filters, artificial sugar substitute products (review)
Summary
The data on the concentrations of illegal drugs (cocaine and its metabolites, opioids, marihuana derivatives, amphetamine and ecstasy group compounds), ultraviolet filters found in sun protection creams (titanium dioxide, para-aminobenzoates, cinnamates, benzophenones, dibenzoylmethanes, camphor derivatives, benzimidazoles), and artificial sugar substitute products (sucralose, aspartame, saccharin, acesulfame) in waste, surface, ground and drinking water are presented. As a result of incomplete removal in the processes of physical, chemical and biological treatment at the traditional wastewater treatment facilities the given pollutants get into the natural aquatic environment where can be found in concentrations mainly of nanograms per liter of water. In foreign countries a marked increase of studies in the field of aquatic environment pollution with illegal drugs, UV filters and artificial sugar substitute products dates back to the beginning of the 2000-ies. Herewith the main attention is paid to improving the efficiency of degradation of these substances at the treatment facilities; to the transformation in aquatic environment resulted from the impact of the natural factors with possible formation of products more toxic than the original substances; to the potential role of these substances as precursors of water disinfection byproducts; to the mechanism of toxicological effect and related risks for aquatic organisms and human beings; to the development of analytical methods.
Key words
toxicological effect , drugs , ultraviolet filters , artificial sugar substitute products , aquatic environment , photodegradation
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