Discrete frequency downshifting in wave spectra on shallow water

Wind waves propagating in the coastal zone, are subject to various changes associated primarily with the impact of nonlinear and dissipative processes. Wave transformation leads to change in the shape of wave spectrum. Sometimes, the major peak frequency shifts to the low-frequency region and so-called “frequency downshifting” are observed. It is not completely understood in details how this process occurs and the detailed mechanism is still not known. For example, on deep water frequency downshifting occurs discretely with a frequency step equal to the difference between the peak frequency and the most unstable low-frequency mode (Saprykina, Kuznetsov, 2016). In moststudies, it is assumed that this is the result of wave breaking and dissipation of wave energy in the high-frequency part of the spectrum (Tulin, Waseda, 1999). As shown by modern theoretical and experimental studies, the nonlinear processes are dominant for wave evolution both in deep and shallow water. In particular, additional frequency peaks can be formed due to spectrum broadening as a result of the backward transfer of energy from higher frequencies (Saprykina et al., 2009) and infragravity frequencies to the main peak (de Bakkeret al.,Tissier, Ruessink, 2016). The main aim of this study is to find out relative contribution of nonlinear and dissipative processes in low-frequency spectral peak formation and the frequency downshifting process

Basic Principles of Comprehensive Biotesting of Drinking Water and Point System Classification of Water Quality

Basic principles of forming test systems for biotesting of natural and drinking waters, and the factors affecting test-systems during the biotesting procedure have been studied. New directions of selecting sensitive test reactions of organisms and test criteria for the quality assessment of natural and drinking waters based on the results of comprehensive biotesting are proposed. The universal point system for drinking water quality estimation was developed. It is based on summation of biotesting results using 4-5 species of animal and plant test-organisms of different systematic and trophic levels. In addition, the total toxicity index of water samples under investigation was also developed. The findings were used in the preparation of the State Standard of Ukraine "Quality of water. Comprehensive biotesting of natural water. Requirements to the selection and cultivation of test organisms. Water quality classification based on the point system"

Genetically Safe Drinking Water. Requirements and Methods of Its Quality Control

The article contains a substantiation of a necessity of a new standard for assessment of the quality of genetically safe drinking water designed for consumption by man. Requirements to the quality of such water include 76 indices and are presented by 10 individual groups; extended is the number of indices of drinking waters of the level of toxicity (biotesting in 7 test objects), normative references to the methods of their control

Genetically Safe Drinking Water. Requirements and Methods of Its Quality Control

The article contains a substantiation of a necessity of a new standard for assessment of the quality of genetically safe drinking water designed for consumption by man. Requirements to the quality of such water include 76 indices and are presented by 10 individual groups; extended is the number of indices of drinking waters of the level of toxicity (biotesting in 7 test objects), normative references to the methods of their control

Basic Principles of Comprehensive Biotesting of Drinking Water and Point System Classification of Water Quality

Basic principles of forming test systems for biotesting of natural and drinking waters, and the factors affecting test-systems during the biotesting procedure have been studied. New directions of selecting sensitive test reactions of organisms and test criteria for the quality assessment of natural and drinking waters based on the results of comprehensive biotesting are proposed. The universal point system for drinking water quality estimation was developed. It is based on summation of biotesting results using 4-5 species of animal and plant test-organisms of different systematic and trophic levels. In addition, the total toxicity index of water samples under investigation was also developed. The findings were used in the preparation of the State Standard of Ukraine "Quality of water. Comprehensive biotesting of natural water. Requirements to the selection and cultivation of test organisms. Water quality classification based on the point system"

Determination of Biological Activity of Water Having a Different Isotope Ratio of Protium and Deuterium

Peculiarities of the vital activity of organisms at different concentrations of the D/H isotope ratio in water have been studied. It was established that many organisms react in different ways to both high and low concentrations of deuterium in water resulting in the reduction or enhancement of the activity of metabolic processes. However, the majority of test organisms have optimal indicators within the limits of natural D/H isotope ratio in water. The experiments with human cells in vitro revealed that the reduced deuterium concentrations significantly changed the vital activity indicators of cultures in deuterium-depleted water media. It was found out that not all taxonomic groups of organisms could be sensitive to changes of the D/H isotope ratio in water

Determination of Biological Activity of Water Having a Different Isotope Ratio of Protium and Deuterium

Peculiarities of the vital activity of organisms at different concentrations of the D/H isotope ratio in water have been studied. It was established that many organisms react in different ways to both high and low concentrations of deuterium in water resulting in the reduction or enhancement of the activity of metabolic processes. However, the majority of test organisms have optimal indicators within the limits of natural D/H isotope ratio in water. The experiments with human cells in vitro revealed that the reduced deuterium concentrations significantly changed the vital activity indicators of cultures in deuterium-depleted water media. It was found out that not all taxonomic groups of organisms could be sensitive to changes of the D/H isotope ratio in water