[Dolphin's flukes: A mathematical model of rigid wing].

New analytical method is used to estimate hydrodynamic forces produced by dolphin's flukes. A mathematical model is proposed that describes dolphin's flukes as a flat rigid rectangular wing whose pitch axis location varies, heaving and pitching amplitudes are sufficiently large, and the phase angle shift for the combined oscillations can change arbitrarily. The dolphin's flukes kinematic parameters are obtained and used to estimate hydrodynamic forces.

[Effect of mineral suspended matter on the productive characteristics of bacterioplankton and the degradation of labile organic materials]. / Vliianie mineral'noi vzvesi na funktsional'nye kharakteristiki bakterioplanktona i destruktsiiu labil'nogo organicheskogo veshchestva.

The effect of mineral particulate matter on the population of bacterioplankton, its aggregation, and productive characteristics was studied in model experiments with different concentrations of particulate kaolin and the same concentration of organic substance (sodium humate). It was found that the presence of mineral particulate matter stimulated the aggregation of bacterioplankton, improved bacterial production, and extended the productive period of bacterioplankton. The integral specific production of aggregated bacterioplankton was higher than that of free-swimming bacterioplankton. The energy metabolic coefficient K2 of bacterioplankton in the presence of mineral particulate matter was higher than in its absence.

[Functional characteristics of bacterioplankton with reference to its aggregation in water bodies of different types]. / Funktsional'nye kharakteristiki bakterioplanktona v sviazi s ego agregirovannost'iu v vodoemakh raznogo tipa.

The functional characteristics of bacterioplankton have been studied with reference to its aggregation in water bodies of different types. Several methods were used for calculation of the total numbers of bacteria and proportion of aggregated cells. Analysis of the experimental data has shown a relationship between the functional characteristics of bacterioplankton, such as bacterial production, destruction of organic matter, and energy coefficient, and the proportion of aggregated bacteria. It has been shown that as this proportion increases, the production per cell and energy coefficients also increase.

[Effect or preliminary filtration on the functional characteristics of bacterioplankton from Lake Khanka]. / Vliianie predvaritel'noi fil'tratsii na funktsional'nye kharakteristiki bakterioplankton ozera Khanka.

The dependence of the functional characteristics of bacterioplankton from the loess of Lake Khanka on the pore size of filtering materials was investigated. Soluble organic matter (SOM), bacteria, and bacterial consumers adsorbed on particles suspended in the lake water were found to filter differently depending on the pore size of the filtering material. Filters with pore size 4.5 microns (filters II) retained up to 20% of SOM and 20-30% of bacterial cells. Filters III with pore size 2.87 microns retained almost 50% SOM and about 40% of bacteria. The double layer of gauze no. 72 (referred to as filter I) with pores size 40 microns was unable to completely retain bacterial consumers. In the case of filtrates I and II, the generation time of bacterioplankton decreased with its increasing average daily concentration. In the case of filtrate III, the generation time of bacterioplankton was minimum and did not depend on its concentration. Oxygen consumption rates per one bacterial cell and per unit biomass in filtrates increased with decreasing pore size of the filters through which they had passed. The bacterial biomass and oxygen consumption rate increased exponentially in filtrates III and logarithmically in filtrates I.

[Characteristics of bacterioplankton in the Loess-containing Lake Khanka]. / Issledovanie kharakteristik bakterioplankton ozera Khanka v sviazi s lessovost'iu vodoema.

Some characteristics of bacterioplankton--generation time, daily (P) and specific (P/B) bacterioplankton production, and bacterial metabolic coefficient K2--in the loess-containing Lake Khanka were determined using five modifications of the bacterial-count procedure with the fluorescent dyes fluorescamin and erythrosin. Experiments showed that the organomineral complex (OMC) in this lake is broken down by chemoorganoheterotrophic bacteria. The increase in the loess content of the lake water intensified bacterial growth and the cycles of potassium, silicon, and other biogenic elements. The addition of starch to a loess suspension activated the breakdown of OMC due to the adsorption of starch on the OMC/water interface and stimulation of the metabolism of attached bacteria.

Parametric solution of the inverse light-scattering problem for individual spherical particles.

We analyze the relation between spherical particle parameters (size parameter ? and relative refractive index m ) and light-scattering indicatrix parameters (fringe pitch and visibility) for ?and m ranging from 7 to 88 and from 1.025 to 1.2, respectively. We consider formation of the indicatrix structure under variation of size parameter ? and phase-shift parameter ? =2 ?(m - 1). We show that indicatrix visibility depends basically on the phase-shift parameter whereas fringe pitch depends on the size parameter. An analysis of these dependencies allows us to determine the region in the ? x ? map where particle parameters can be derived unambiguously from indicatrix parameters. We clarify errors in determination of particle characteristics on the basis of the approximating equations that relate particle size and phase shift to indicatrix parameters.

[Refractive index and thickness of the outer layer of particles of dispersed perfluorochemical-based blood substitutes]. / Opredelenie pokazatelia prelomleniia i tolshchiny obolochki chastits dispersnogo krovezamenitelia na osnove perftorsoedinenii.

A calculation of the refractive index of particles of a disperse perfluorochemical-based (PFC-based) blood substitute has been made taking into account particular features of the structure of PFC emulsion particles and the equations earlier obtained by one of the authors in the studies on light interaction with optically inhomogeneous 2- and 3-layer spheres. The possibility of averaging by volume the refractive index of 2-layer emulsion particles has been shown. The refractive index of PFC particles has been experimentally determined using independent optical methods, and the thickness of the particle shell formed by a surfactant has been evaluated.