In the process of growing in a recycling plant in artificially created conditions, it is necessary to control and regulate the production of vital substances by fish. It is important to take into account the age and type of fish being studied. This paper presents the results of administration of vitamin B12, vitamin E and selenium preparations in the form of injections in order to achieve physiological preparation of sturgeon producers for spawning. The study of fish-biological characteristics of fish revealed an increase in growth indicators in the control variant (by 1.66 % in comparison with the experiment), as the fish of the experimental group showed acceleration of generative metabolism and the number of individuals with gonads at the 4th stage of maturity was higher by 4.6 % in comparison with the control variant.

The paper presents the study results of the various recipes of production trout mixed fodders produced by LLC "RybProm" on the condition of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) during its cultivation in cages in comparison with the feed produced by Coppens. The physiological condition of the studied fish was evaluated, haematological, biochemical studies and pathological and anatomical autopsy were carried out. It was shown that the feed coefficient in the control group was 1.2, and in the experimental feeds from 1.3 to 1.5. Of the three studied feeds, the feed "Recipe #3" is practically not inferior in feed coefficient and growth rate to the control group. The conducted researches at the cage trout farm showed that the feeds of domestic production correspond to imported analogues. All studied feed recipes are safe for the health of rainbow trout and are sufficiently balanced for its cultivation in cages.

This study was conducted in order to investigate of the points of formation of ice particles during cooling of fish sperm. The object of the study was spermatozoa of the Russian sturgeon (Acipenser gueldenstaedtii Brandt, 1833), hybrid Acipenser ruthenus × Huso huso, the spiny-tailed sturgeon Acipenser nudiventris Lovetsky, 1828, and the inconnu Stenodus leucichthys Güldenstädt, 1772. The growth of ice microparticles is formed at the perturbation temperature of the corresponding aqueous suspension, with the concentration of dissolved substances increasing in the non-freezing phase. The process of ice formation and the increase concentration of the remaining liquid continues as it cools to form amorphous (glassy) ice. It is interesting to bring the mass of ice with a further decrease in temperature to (-196) ° C. Cooling causes compression of the formed ice crystals.

The sperm of Russian sturgeon (Acipenser gueldenstaedtii Brandt et Ratzeburg, 1833) was the research object. Acoustic-mechanical influence on sturgeon semen improves fish-biological and reproductive indices of the seminal fluid. The most optimal indices for reproductive cells of male Russian sturgeon are 500 Hz, 90 V with the exposure duration of 1 minute. It has been shown that when a piezo-actuator with a frequency of 500 Hz and an amplitude of 90 V is applied to the sperm mixture with the cryoprotectant, ice crystals are formed later, which may influence the survival of cells after defrosting.

The methods of cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy were used to study the effect of electrolyte redox on the electrochemical characteristics of a composite based on a poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer and multiwalled carbon nanotubes (MWCNTs). To form a uniform thin layer of PEDOT on the surface of nanotubes, an enzymatic polymerization of the monomer was used. The electrochemically active compound sodium 1,2‑naphthoquinone-4-sulfonate (NQS) was a dopant in the main PEDOT chain and, at the same time, a component of the electrolyte. The addition of 12.5 mM NQS to the electrolyte increased the specific capacitance of the PEDOT–NQS/MWCNT composite electrode from 390 to 800 F/g at a potential sweep rate of 10 mV/s. In a 1 M H2SO4 + 12.5 mM NQS redox electrolyte, the composite electrode exhibited higher cyclic stability and lower charge transfer resistance compared to 1 M H2SO4. After 1000 cycles of potential scanning in the range from –0.1 to 0.8 V at a rate of 100 mV/s, the specific capacitance of the composite electrode in a solution of 1 M H2SO4 decreased by 8

The electrochemical characteristics of carbonaceous materials differing in their specific surface area and porosity are studied by the method of cyclic voltammetry in 0.25 М LiClO4/DMSO electrolyte, both in inert and oxygen atmosphere. The value of the electrochemically active surface area that was estimated from cyclic voltammograms as the polarization capacitance was shown to increase with increase in the BET specific surface area. The efficiency in the oxygen reaction, measured in the oxygen atmosphere and expressed as the charge consumed for the formation of Li2O2 (QC) in the oxygen reduction reaction (the cathodic segment), and the process reversibility, expressed as the ratio of the charge consumed for oxygen evolution (QA) (the anodic segment) to QC, are mainly determined by the electrochemically active surface area and the porosity of the carbonaceous material.

Platinum catalysts synthesized at carbon nanotubes with the noble metal content of 20 and 40 wt % are studied under model conditions and in cathodes of membrane-electrode assemblies (MEA) of hydrogen–air fuel cells with proton-conducting polymer electrolyte. The effect of the cathode active layer and MEA overall composition on the activity and operation stability of the synthesized catalytic systems is elucidated. Stability against degradation is studied by using the accelerated stress-testing method by the cathode potential repeated cycling over the 0.6–1.3 V range. The synthesized catalysts were shown to possess higher stability against degradation as compared to the commercial 60Pt/C catalysts (HiSPEC). Contribution of the electrochemical, Ohmic, and transport components into the overall voltage losses depends on the total platinum surface area in the active layers, which determines the polarization current density, and on the Pt mass at the support. The higher Ohmic and transport losses in the case of the catalyst with the Pt content of 40 wt %, as compared to the catalyst containing 20 wt % of platinum, are due to the structural characteristics, namely, a decrease in the carbon nanotubes’ pore volume and size when a greater metal load is applied.

The influence of different temperature regimes (28 ° C and 25 ° C) on the early ontogeny of Clarias gariepinus was studied. Heterochronism in the development of the main systems has been provided: the central nervous system and the digestive system are actively developing, the formation of the cardiovascular, respiratory and genitourinary systems occurs more slowly. The duration of embryonic development within the membranes was 18-22 hours. The initial stages of development changed insignificantly with decreasing temperature. The duration of the larval period was 14 days at 28 ° C and 15 days at 25 ° C. The fry period lasted 30 and 32 days, respectively. In terms of the duration of embryogenesis and the timing of the release of free embryos, the indicators did not go beyond the norm. The percentage of ugly embryos (underdevelopment of the operculum, underdevelopment of the tail, head and fins) was small and amounted to 3.2%, in the first and 4% in the second temperature regime. Incubation at temperatures below the optimum temperature of this species makes it possible to obtain viable offspring, adapted to the change in temperature regime.

In industrial aquaculture, spawning of t*he Clarias catfish (lat. Clarias gariepinus) is complicated by the fact that it is impossible to obtain sperm due to the physiology of the fish. Fish farmers deal with the problem in different ways. They have to expect natural spawning, do a resection of the gonads or kill and dissect the fish (slaughter). We would like to propose a method for collecting sperm through the puncture of the gonads of the fish. The method is intended to save male broodstock. If the weight of the fish does not exceed 2 kg, the procedure can be performed any anesthesia. There is no need for the fish to be separated from the rest of the broodstock after the surgery. 43 of the 65 stimulated one-year-old males with an average weight of 1250 g have given motile sperm with a volume of 1.5 ± 0.1 ml.

Full computer simulation of the cathode structure in hydrogen–oxygen fuel cell with polymer electrolyte is performed. Both transport, support grains (agglomerates of carbon particles onto whose surface Pt-catalyst is deposited), and the current generation in active layer are simulated. The active layer operation in potentiostatic mode is studied. The effect of variations of the active layer and the fuel cell temperature (Ts and Т, respectively) on the cathode overall current I and the support grain flooding with water is calculated. The changes in the temperature difference Ts–Т was shown for the first time, experimentally and by the simulation, to generate variations of I and the degree of the support grain flooding with water. In particular, with the increasing of Ts–Т the current I increased, whereas the support grain flooding with water decreased; and vice versa, with the decreasing of Ts–Т the current I drops down, while, the support grain flooding with water grows. An explanation of the phenomena is presented, which takes account of structure of the support grains in which О2 reduction and Н2О generation occur. There exist intrinsic channels for protons and О2 molecules transportation to the catalyst. Water releasing in the support grains is able to fill partially or even entirely the gas pores through which oxygen is supplied to the platinum. As a result, the current generated in the support grains can drop down significantly; at the same time, the value of I also drops down. The degree of the support grainfilling with water is determined by two processes, namely, the flooding and draining. The source of flooding is the current generation; that of draining, the water saturated vapor diffusion and water filtration in nanopores. The lower cathode potential, the higher the flooding rate, whereas the water removal rate grows or drops down with the increasing of decreasing of the temperature difference Тs–Т, respectively. Thus, the temperature difference variations naturally lead to those of the quantity I.

The characteristics of low-temperature hydrogen–oxygen (air) fuel cell (FC) with cathodes based on the 50 wt % PtCoCr/C and 40 wt % Pt/CNT catalysts synthesized on XC72 carbon black and carbon nanotubes (CNT) are compared with the characteristics of commercial monoplatinum systems 9100 60 wt % Pt/C and 13100 70% Pt/C HiSPEC. It is shown that the synthesized catalysts exhibit a high mass activity, which is not lower than that of commercial Pt/C catalysts, a high selectivity with respect to the oxygen reduction to water, and a significantly higher stability. The characteristics of PtCoCr/C and Pt/CNT were confirmed by testing in the hydrogen—oxygen FCs. However, when air was used at the cathode, especially in the absence of excessive pressure, a voltage of FC with the cathode based on PtCoCr/XC72 is lower as compared with the commercial systems. Probably, this is associated with the transport limitations in the structure of trimetallic catalyst synthesized on XC72 carbon black due to the absence of mesopores. This drawback was eliminated to a large extent by raising the volume of mesopores as a result of application of mixed support (XC72 + CNT) and the use of only CNT for the synthesis of the monoplatinum catalyst. However, this did not eliminate another drawback, namely, a low platinum utilization coefficient in the cathode active layer as compared with that measured under the model conditions in the 0.5 M Н 2 SO 4 solution. Therefore, further research is required to improve the structure of the catalytic systems, which are synthesized both on carbon black and nanotubes, while maintaining their high stability and selectivity.

Pyrolysis of nitrogen-containing complexes of iron and cobalt on the surface of disperse carbon materials was used for synthesis of cathode catalysts for oxyhydrogen fuel cells (FC) with proton-conducting (acidic) and anion-conducting (alkaline) electrolytes. The catalysts were characterized by XPS and tested using a thin-film disc electrode and in oxyhydrogen FC under model conditions. Properties of the CoFe/C system prepared by pyrolysis of macroheterocyclic compounds of iron and cobalt on carbon materials (soot HS-72 and multilayer nanotubes (CNT)) were described for the first time. From XPS data, the surface of the catalytic CoFe/C systems is rich in carbon (95,5 at.%), contains nitrogen (2 at.%), oxygen (2 at.%) and metals (0,5 at.%). The data obtained by electrochemical measurements under model conditions revealed that the catalytic systems CoFe/CNT are close to the commercial platinum catalyst 60%Pt/C (HiSPEC9100) in their activity to oxygen reduction in an alkali medium (0,5 M KOH). Half-wave potentials are 0,85 and 0,88 V for catalysts CoFe/CNT and 60%Pt/C (HiSPEC9100), respectively. The maximal specific capacity of the oxyhydrogen FC with an anion-conducting electrolyte is 210 mW/cm2 (a 60%Pt/C (HiSPEC9100) based cathode) and 180 mW/cm2 (CoFe/CNT based cathode). In its characteristics, MEA with the non-platinum cathode compete well with the best analogues described in literature. The results obtained demonstrated the necessity of the further studies on scaling-up the technology for synthesis of the developed non-platinum cathode catalysts and on optimization of the MEA FC architecture based thereon.

Рассмотрены современные задачи в области электрокатализа токогенерирующих реакций низкотемпературных водородо-воздушных топливных элементов (ТЭ). Эти задачи сформулированы в рамках основных закономерностей электрокатализа и его непосредственной связи с электрохимической кинетикой и адсорбционными процессами на межфазной границе. Анализ опубликованных данных и материалов, представленных на специализированных конференциях по ТЭ в США, Канаде и Англии, показывает, что целью мировой электрохимической науки является снижение расхода платины вплоть до ее полного устранения и решение вопроса об использовании дешевого водорода с примесями СО и СО 2 из различных альтернативных источников. На примере исследований в ИФХЭ РАН продемонстрированы результаты работ в этих направлениях.

Results on the development of new cathodic catalysts (monoplatinum and cobalt-modified platinum) applied on carbon nanotubes are shown. By means of a complex of electrochemical and structural techniques, it is shown that as regards their activity under model conditions and within membrane-electrode assembles, the catalysts synthesized by the polyol method are close to commercial monoplatinum systems with the same mass content of platinum (20 wt %) and their corrosion stability is double that of commercial catalysts. Platinum modified with cobalt is characterized by still higher stability, which allows considering these catalytic systems as the candidates to be used in fuel cells after the corresponding optimization.